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The aim of this study was to assess local response to radiotherapy (RT) in a quantitative manner by evaluating the bone density of metastases. Spinal and pelvic bone metastases in 44 patients with breast cancer who were treated between May 2010 and December 2016 were retrospectively assessed. Bone density values of irradiated and unirradiated bone metastases before, 1–3 months after, 4–6 months after, and 7–9 months after RT were compared. At each time point, mean bone density ± standard deviation values were measured in Hounsfield units (HU) from computed tomography (CT) scans. Student’s t-test was used for statistical analyses of the differences in bone density and for univariate analysis of the prognostic factors for differences in bone density at various time points after RT. Mean bone densities in irradiated and unirradiated bone metastases before RT were 297.31 ± 211.93 HU and 326.29 ± 228.61 HU, respectively. At the subsequent three time points examined, the mean bone density values in the irradiated and unirradiated bone metastases were: 61.97 ± 78.58 HU (P = 0.000) and 36.93 ± 52.49 HU (P = 0.001); 149.07 ± 133.27 HU (P = 0.000) and 68.40 ± 101.10 HU (P = 0.000); and 183.94 ± 168.30 HU (P = 0.000) and 88.21 ± 159.49 HU (P = 0.004), respectively, in each case. Patients receiving bisphosphonates exhibited greater increases in bone density in their metastases 1–3 months after RT (83.04 ± 82.18 HU vs 26.86 ± 60.55 HU, respectively; P = 0.044), whereas chemotherapy before RT was associated with significantly lower increases in bone density at the subsequent three time points [(37.53 ± 67.66 HU vs 93.63 ± 80.36 HU, P = 0.027), (99.30 ± 107.92 HU vs 180.24 ± 127.85 HU, P = 0.030), and (126.07 ± 141.77 HU vs 236.28 ± 158.22 HU, P = 0.024), respectively, in each case]. Comparing bone density values determined from CT scans appears to be a practicable and reproducible method for assessing local response to RT for bone metastasis of breast cancer. Increased bone density was also observed in the irradiated bone metastases.

International audience; More than 35% of lung adenocarcinoma patients have bone metastases at diagnosis and have a poor survival. Periostin, a carboxylated matrix protein, mediates lung cancer cell dissemination by promoting epithelial-mesenchymal transition, and is involved in bone response to mechanical stress and bone formation regulation. This suggests that periostin may be used as a biomarker to predict survival in lung cancer patients.Serum periostin was assessed at diagnosis in a prospective cohort of 133 patients with lung adenocarcinoma of all stages. Patients were divided into localized and bone metastatic groups. Both groups were matched to healthy controls. Survival analysis and Cox proportional hazards models were conducted in the total population and in bone metastatic group.The median serum periostin level was higher in bone metastatic (n = 67; median: 1752 pmol/L) than in the localized group (n = 66; 861 pmol/L; p median) had a poorer overall survival in the whole population (33.3 weeks vs. NR; p

Highlights • Retrospective clinical review of 167 patients with breast cancer bone metastases. • Comprehensive study of clinical characteristics, prognostic factors, and survival. • First study to assess outcomes associated with operative vs. nonoperative treatment. • Utilizing surgical treatment involves a complex, personalized care decision., Introduction Bone is the most common distant site of breast cancer metastasis. Skeletal lesions can cause significant morbidity due to pain, pathologic fracture, and electrolyte abnormalities. Current treatment for patients with bone metastases (BoM) from breast cancer is highly personalized and often involves a multidisciplinary approach with chemotherapy, hormone therapy, bone-targeted antiresorptive agents, radiation therapy, and surgery. We have retrospectively collected clinical data from a series of patients with bone metastases to evaluate the clinical characteristics, prognostic factors, and survival patterns of patients with breast cancer BoM receiving standard multimodal therapy. Methods A consecutive series of 167 patients with breast cancer BoM treated at a single institution between August 2013 and March 2020 were identified. Clinical information was obtained from the medical record and survival analyses were performed to evaluate patient outcomes and identify prognostic factors. Results Thirty-seven patients (22%) presented with de novo BoM – bone metastases at the time of breast cancer diagnosis – and were 2.6 times more likely to die within the study period than those with asynchronous BoM (HR = 2.62, p =

Background: In the current study we evaluated 68Ga PSMA PET/ CT to measure local control of bone metastasis in oligometastatic prostate cancer patients treated with SBRT. Materials and methods: After the institutional review board approval, a retrospective review of medical records of consecutive prostate cancer patients treated between 2014 and 2018 was conducted. Only medical records of patients that were treated with SBRT for bone metastasis and had pre-and post-SBRT 68Ga PSMA PET/CT scans were included in our study. Data extracted from the medical files included patient-related (age), disease-related (Gleason score, site of metastasis), and treatment-related factors and outcomes. Results: During the study period, a total of 12 patients (15 lesions) were included, with a median age of 73 years. The median follow-up was 26.5 months (range 13–45 months). Median time of 68Ga PSMA PET/ CT follow up was 17.0 months (range 3–39 months). The median pre-treatment PSA was 2 ng/mL (range 0.56–44 ng/mL) vs. post treatment PSA nadir of 0.01 ng/mL (0.01–4.32) with a median time to nadir of 7 months (range, 2–12). Local control was 93% during the follow up period and there was correlation with PSMA avidity on PET. None patients developed recurrences in the treated bone. None of the patients had grade 3 or more toxicities during follow-up. Conclusions: SBRT is a highly effective and safe method for treatment of prostate cancer bone metastases. More studies are required to determine if SBRT provides greater clinical benefit than standard fractionation for oligometastatic prostate cancer patients. 68Ga PSMA PET/CT should be further investigated for delineation and follow-up.

Objective: Lung cancer patients exhibit spinal metastases from a specific population, and with this study, we aimed to develop a model that can predict this particular group's survival. Methods: Data were retrospectively collected from 83 lung cancer patients who underwent spinal metastasis surgery at our center from 2009 to 2021. After the initial assessment of treatment and scoring effects, a nomogram for survival prediction was created by identifying and integrating critical prognostic factors, followed by a consistency index (C-index) to measure consistency, and finally, a subject working characteristic curve (ROC) to compare the predictive accuracy of the three existing models. Results: The mean postoperative survival was 14.7 months. Surgical treatment significantly improved the VAS and Frankel scores in lung cancer patients with spinal metastases. The revised Tokuhashi score underestimated the life expectancy of these patients. Six independent prognostic factors, including age, extraspinal bone metastasis foci, visceral metastasis, Frankel score, targeted therapy, and radiotherapy, were identified and incorporated into the model. Calibration curves for 3-, 6-, and 12-month overall survival showed a good concordance between predicted and actual risk. The nomogram C-index for the cohort study was 0.800 (95% confidence interval [CI]: 0.757-0.843). Model comparisons showed that the nomogram's prediction accuracy was better than revised Tokuhashi and Bauer's scoring systems. Conclusions: Spine surgery offered patients the possibility of regaining neurological function. Having identified shortcomings in existing scoring systems, we have recreated and validated a new nomogram that can be used to predict survival outcomes in patients with spinal metastases from lung cancer, thereby assisting spinal surgeons in making surgical decisions and personalizing treatment for these patients.

Medication-related osteonecrosis of the jaw (MRONJ) is an adverse event associated with antiresorptive and antiangiogenic drugs. The use of these drugs in the treatment of cancer patients with bone metastasis is necessary and standardized in the literature. A multidisciplinary approach for the patient’s management is strongly recommended. Therefore, it should be necessary to integrate the path of these subjects with a dedicated dental screening in order to first assess the individual risk of developing a MRONJ, and then to plan dental treatments and oral hygiene sessions, and finally to schedule a follow-up to intercept and treat early osteonecrosis. The aim of this manuscript is to propose a new simple medical report to evaluate patients affected by metastatic bone cancer in order to reduce the risk of developing MRONJ.

Optimum management of patients with cancer during the COVID-19 pandemic has proved extremely challenging. Patients, clinicians and hospital authorities have had to balance the risks to patients of attending hospital, many of whom are especially vulnerable, with the risks of delaying or modifying cancer treatment. Those whose care has been significantly impacted include patients suffering from the effects of cancer on bone, where delivering the usual standard of care for bone support has often not been possible and clinicians have been forced to seek alternative options for adequate management.\ud \ud \ud \ud At a virtual meeting of the Cancer and Bone Society in July 2020, an expert group shared experiences and solutions to this challenge, following which a questionnaire was sent internationally to the symposium’s participants, to explore the issues faced and solutions offered. 70 respondents, from 9 countries (majority USA, 39%, followed by UK, 19%) included 50 clinicians, spread across a diverse range of specialties (but with a high proportion, 64%, of medical oncologists) and 20 who classified themselves as non-clinical (solely lab-based). Spread of clinician specialty across tumour types was breast (65%), prostate (27%), followed by renal, myeloma and melanoma.\ud \ud \ud \ud Analysis showed that management of metastatic bone disease in all solid tumour types and myeloma, adjuvant bisphosphonate breast cancer therapy and cancer treatment induced bone loss, was substantially impacted. Respondents reported delays to routine CT scans (58%), standard bone scans (48%) and MRI scans (46%), though emergency scans were less affected. Delays in palliative radiotherapy for bone pain were reported by 31% of respondents with treatments often involving only a single dose without fractionation. Delays to, or cancellation of, prophylactic surgery for bone pain were reported by 35% of respondents. Access to treatments with intravenous bisphosphonates and subcutaneous denosumab was a major problem, mitigated by provision of drug administration at home or in a local clinic, reduced frequency of administration or switching to oral bisphosphonates taken at home. The questionnaire also revealed damaging delays or complete stopping of both clinical and laboratory research.\ud \ud \ud \ud In addition to an analysis of the questionnaire, this paper presents a rationale and recommendations for adaptation of the normal guidelines for protection of bone health during the pandemic.

Background: Advanced breast cancer metastasizes to many organs including bone, but few effective treatments are available. Here we report that induced tumor-suppressing (iTS) MSCs protected bone from metastases while un-induced MSCs did not. Methods: iTS MSCs were generated by overexpressing Lrp5, β-catenin, Snail, or Akt. Their tumor-suppressing capability was tested using a mouse model of mammary tumors and bone metastasis, human breast cancer tissues and cancer cell lines. Results: In a mouse model, the induced MSC-derived conditioned medium (MSC CM) reduced mammary tumors and suppressed tumor-induced osteolysis. Tumor-promoting genes such as CXCL2 and LIF, as well as PDL1, a blocker of T-cell-based immune responses were downregulated. Proteomics analysis revealed that heat shock protein 90 (Hsp90ab1), calreticulin (Calr) and peptidylprolyl isomerase B (Ppib), which are highly expressed intracellular proteins in many cancers, were enriched in MSC CM as atypical tumor suppressors. Thus, overexpressing selected genes that were otherwise tumorigenic rendered MSCs the tumor-suppressing capability through the atypical suppressors, as well as p53 and Trail. Notably, the inhibitory effect of Lrp5- and Akt-overexpressing MSC CMs, Hsp90ab1 and Calr presented selective inhibition to tumor cells than non-tumor cells. The development of bone-resorbing osteoclasts was also suppressed by MSC CMs. Conclusion: Collectively, the results showed an anti-tumor effect of iTS MSCs and suggested novel therapeutic approaches to suppress the progression of tumors into the bone.

Approximately 90% of cancer-related deaths result from cancer metastasis. In prostate and breast cancers, bone is the most common site of cancer cell dissemination. Key steps in the metastatic cascade are promoted through upregulation of critical cell signaling pathways in neoplastic cells. The present study assessed the role of the receptor tyrosine kinase Axl in prostate and breast cancer cell metastasis to bones using (i) Axl knockdown neoplastic cells and osteoclast progenitor cells in vitro, (ii) intracardiac injection of Axl knockdown tumor cells in vivo, and (iii) selective Axl inhibitor BGB324. Axl inhibition in neoplastic cells significantly decreased their metastatic potential, and suppression of Axl signaling in osteoclast precursor cells also reduced the formation of mature osteoclasts. In vivo, Axl knockdown in prostate and breast cancer cells significantly suppressed the formation and progression of bone metastases. Hence, therapeutic targeting of Axl may impair tumor metastasis to the bones through neoplastic and host cell signaling axes.

Background:CTCs have extensively used for the monitoring and characterization of metastatic prostate cancer, but their use in the clinic is still very scarce. Besides, the resistance mechanisms linked to prostate cancer treatment remain unclear. Liquid biopsies represent the most promising alternative due to the complexity of biopsying bone metastasis and the duration of the disease. Prostate cancer can last from a few months to many years, where the primary tumour does not represent the molecular features of the advanced stage. Methods:We performed a prospective longitudinal study in CTCs from 20 castration-resistant prostate cancer patients treated with docetaxel. For that, we used CellSearch® technology and a custom gene expression panel with qRT-PCR using a CTCs negative enrichment approach.Results:We found that CTCs showed a hybrid phenotype during the disease, where epithelial features were associated with the presence of ≥ 5 CTCs/7.5 mL of blood, while high relative expression of the gene MYCL was observed preferentially in the set of samples with < 5 CTCs/7.5 mL of blood. At baseline, patients whose CTCs had epithelial features showed an early progression. After 1 cycle of docetaxel, high relative expression of ZEB1 indicated worse outcome, while KRT19 and KLK3 high expression predisposed the patients to a worse prognosis at clinical progression.Conclusions:In the present work we describe biomarkers with clinical relevance for the prediction of early response or resistance in castration-resistant prostate cancer patients. Besides, we question the utility of targeted isolated CTCs and the use of a limited number of markers to define the CTCs population.

Cancer-associated bone disease is a frequent occurrence in cancer patients and is associated with pain, bone fragility, loss, and fractures. However, whether primary or non-bone metastatic gastric cancer induces bone loss remains unclear. Here, we collected clinical evidence of bone loss by analyzing serum and X-rays of 25 non-bone metastatic gastric cancer patients. In addition, C57BL mice were injected with the human gastric cancer cell line HGC27 and its effect on bone mass was analyzed by Micro-CT, immunoblotting, and immunohistochemistry. Furthermore, the degree of the proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) co-cultured with HGC-27 or SGC-7901 cells was analyzed by colony-formation assay, alizarin red staining, immunofluorescence, qPCR, immunoblotting, and alkaline phosphatase activity assay. These indicated that gastric cancer could damage bone tissue before the occurrence of bone metastases. We also found that cilia formation of MSCs was increased in the presence of HGC27 cells, which was associated with abnormal activation of the Wnt/β-catenin pathway. Expression of DKK1 inhibited the Wnt/β-catenin signaling pathway and partially rescued osteogenic differentiation of MSCs. In summary, our results suggest that gastric cancer cells might cause bone damage prior to the occurrence of bone metastasis via cilia-dependent activation of the Wnt/β-catenin signaling pathway.

Background: Ovarian cancer (OC) is one of the most common malignancies in women. Advanced bone metastases (BM) commonly result in the poor prognosis. We aim to evaluate the prevalence and associated factors for the de novo BM development and prognosis in OC. Materials and methods: The present study was a cohort study that used the United States based National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database. SEER documented OC patients, diagnosed between 2010 and 2015, were included in the present study. Univariable and multivariable logistic regression analyses were employed to identify associated factors for BM development. Kaplan-Meier analysis was used to estimate the overall survival and multivariable proportional hazard regression was used to identify the prognostic factors for OC patients with BM. Results: A total of 32,178 eligible OC patients were included in the present study, the prevalence of de novo BM was 1.09% (N=352). Non-serous histology [Odds Ratio (OR)=3.05; 95% CI: 1.63-5.72; P=0.001], T2/T1 stage (OR=3.39; 95% CI: 1.11-10.33; P=0.03), N1/N0 stage (OR=3.17; 95% CI: 1.72-5.84; P

Background and Aims: Prostate specific membrane antigen (PSMA) is specifically expressed on prostate epithelial cells and markedly overexpressed in almost all prostate cancers. TRIM24 is also up-regulated from localized prostate cancer to metastatic castration-resistant prostate cancer (CRPC). Because of the high relevance of TRIM24 for cancer development and the universal expression of PSMA in CPRC, we investigated the efficacy of human monoclonal PSMA antibody (PSMAb)-based platform for the targeted TRIM24 siRNA delivery and its therapeutic efficacy in CRPC in vivo and in vitro. Methods: The therapeutic complexes were constructed by conjugating PSMAb and sulfo-SMCC-protamine, and encapsulating TRIM24 siRNA. Flow cytometry, immunofluorescence, and fluorescence imaging were performed to detect the receptor-binding, internalization, and targeted delivery of PSMAb-sulfo-SMCC-protamine (PSP)-FAM-siRNA complex (PSPS) in vitro and in vivo. CCK-8, plate-colony formation, apoptosis, cell cycle, and Transwell assays were performed to evaluate the therapeutic potential of the PSP-TRIM24 siRNA complex in vitro, whereas the in vivo therapeutic efficacy was monitored by small animal imaging, radiography, and micro CT. Results: We confirmed that PSP could efficiently protect siRNA from enzymatic digestion, enable targeted delivery of siRNA, and internalize and release siRNA into PSMA-positive (PSMA+) prostate cancer cells in vitro and in vivo. Silencing TRIM24 expression by the PSP-TRIM24 siRNA complex could dramatically suppress proliferation, colony-formation, and invasion of PSMA+ CRPC cells in vitro, and inhibit tumor growth of PSMA+ CRPC xenografts and bone loss in PSMA+ CRPC bone metastasis model without obvious toxicity at therapeutic doses in vivo. Conclusion: PSMAb mediated TRIM24 siRNA delivery platform could significantly inhibit cell proliferation, colony-formation, and invasion in PSMA+ CRPC in vitro and suppressed tumor growth and bone loss in PSMA+ CRPC xenograft and bone metastasis model.

Purpose Breast-conserving treatment (BCT) have emerged as an alternative to mastectomy in patients with ipsilateral breast tumor recurrence (IBTR). We evaluated survival outcomes and treatment-related toxicity in a series of 40 patients with IBTR, who underwent tumorectomy plus interstitial brachytherapy (APBI) as a salvage treatment. Material and methods Retrospective analysis included 40 patients diagnosed with IBTR and treated with intraoperative (26 patients) or post-operative (14 patients) multicatheter brachytherapy for APBI at our institution between June 2002 and October 2017. We assessed cosmesis, toxicity, overall survival (OS), and cancer-specific survival (CSS). Results Tumorectomy was performed in all cases, including intraoperative tumor margin assessment and sentinel node biopsy. Median age was 65 years (range, 41-92). The total prescribed dose was 32 Gy (8 fractions) in 19 patients and 34 Gy (10 fractions) in 20 patients. One elderly patient (age 92) received a single fraction of 16 Gy. Median follow-up was 61.5 months (range, 6-153). A median of 14 tubes were inserted. Mean treated V100 was 115 cc. Two patients developed a second relapse at 3 and 5 years after salvage treatment: one patient underwent salvage mastectomy and remains alive 10 years after brachytherapy, and the second one developed both local relapse and bone metastasis. The disease is stable at present. Five-year OS and CSS rates were 85.3% and 97.5%, respectively. Two patients died from cancer-related causes. Acute and late toxicity rates were low; seven patients developed acute infectious mastitis. Late fibrosis > grade 3 and late mastitis were observed in 14 and 6 cases, respectively. Conclusions Second BCT with APBI as a salvage treatment in ipsilateral breast recurrence achieves good local disease control, with a satisfactory toxicity profile compared to mastectomy. This approach seems to be safe and effective, although more data from randomized trials are needed.

Background/Aim: In the era of immunotherapy, treatment-related lymphopenia (TRL) is gaining attention. In this study, TRL was investigated in patients with bone metastasis from hepatocellular carcinoma (HCC) treated with radiotherapy (RT). Methods: Clinical data of 302 patients receiving RT for 511 bone metastases from HCC between 2005 and 2018 were reviewed. Data on absolute lymphocyte count (ALC) from pre-RT to 12 months post-RT were collected. Severe TRL was defined as ALC 3 and evaluated using ALC 2 months after initiating RT. Factors associated with TRL were analyzed, which include the amount of active bone marrow within the RT field. The amount of active bone marrow included in the RT field was calculated as the product of the percentage of the bone compartment included in the RT field and the active bone marrow percentage of the bone compartment. Results: Overall, 33.4% of patients developed TRL 2 months after initiating RT. The mean ALC decreased after initiating RT and remained persistently low during 12 months of observation. Overall survival (OS) was significantly worse in patients with TRL than in those without (median OS: 3.7 vs. 6.5 months, p < 0.001). In the prognostic factor analysis, TRL was an independent prognostic factor of OS (p = 0.036), along with known prognostic factors of HCC. The percentage of active bone marrow within the RT field was the only significant factor associated with TRL (p < 0.001). Conclusion: TRL was observed in patients receiving RT for bone metastasis from HCC, and it was associated with poor survival. The percentage of active bone marrow within the RT field significantly affected TRL development. The results suggest that a new strategy is required to prevent TRL.

Background: Once prostate cancer developed bone metastasis, the quality of life and prognosis of patients are seriously affected as no effective treatment is currently available. It is necessary to explore the mechanism of bone metastasis and new therapeutic targets. Purpose: To find out the differentially expressed serum proteins in prostate cancer patients with bone metastasis and analyze the expression of key proteins in prostate cancer tissues, serum and prostate cancer cell lines. So as to provide a basis for revealing the mechanism of bone metastasis and designing new therapeutic targets. Methods: iTRAQ-based proteomics method was used to compare serum differential proteins in prostate cancer patients with and without bone metastasis. Three key proteins (CD59, haptoglobin and tetranectin) which had significant fold changes were selected to validate the results of mass spectrometry. Immunohistochemistry and ELISA were applied to tissues and serum samples from prostate cancer patients, respectively, for validation. Finally, western blot, flow cytometry, and immunocytochemistry were used to analyze the expression of the three differentially expressed proteins in the prostate cancer cell lines PC3, LNCap, and Du145. Results: Thirty-two differentially expressed proteins related to bone metastasis of prostate cancer were identified, of which 11 were up-regulated and 21 were down-regulated. CD59 and haptoglobin were up-regulated in prostate cancer with bone metastasis while tetranectin was down-regulated. Tetranectin showed differential expression in epithelial and stromal cells of prostate cancer and hyperplasia tissues.The expression of CD59 was highest in PC3 and lowest in LNCap, while the expression of haptoglobin and tetranectin was the highest in DU145 and lowest in PC3. Conclusion: Mass spectrometry analysis showed that there were more differentially expressed proteins in the serum of patients with bone metastasis than those without metastasis. It has been verified that CD59, haptoglobin and tetranectin are prostate cancer bone metastasis related proteins.

Background: The reciprocal repressive loop between ZEB1 and miRNAs has been extensively reported to play an important role in tumor progression and metastasis of various human tumor types. The aim of this study was to elucidate the role and the underlying mechanism of the double-negative feedback loop between ZEB1and miR-33a-5p in bone metastasis of prostate cancer (PCa). Methods: miR-33a-5p expression was examined in 40 bone metastatic and 165 non-bone metastatic PCa tissues by real-time PCR. Statistical analysis was performed to evaluate the clinical correlation between miR-33a-5p expression and clinicopathological characteristics, and overall and bone metastasis-free survival in PCa patients. The biological roles of miR-33a-5p in bone metastasis of PCa were investigated both by EMT and the Transwell assay in vitro, and by a mouse model of left cardiac ventricle inoculation in vivo. siRNA library, real-time PCR and chromatin immunoprecipitation (ChIP) were used to identify the underlying mechanism responsible for the decreased expression of miR-33a-5p in PCa. Bioinformatics analysis, Western blotting and luciferase reporter analysis were employed to examine the relationship between miR-33a-5p and its potential targets. Clinical correlation of miR-33a-5p with its targets was examined in human PCa tissues and primary PCa cells. Results: miR-33a-5p expression was downregulated in PCa tissues with bone metastasis and bone-derived cells, and low expression of miR-33a-5p strongly and positively correlated with advanced clinicopathological characteristics, and shorter overall and bone metastasis-free survival in PCa patients. Upregulating miR-33a-5p inhibited, while silencing miR-33a-5p promoted EMT, invasion and migration of PCa cells. Importantly, upregulating miR-33a-5p significantly repressed bone metastasis of PC-3 cells in vivo. Our results further revealed that recurrent ZEB1 upregulation induced by copy number gains transcriptionally inhibited miR-33a-5p expression, contributing to the reduced expression of miR-33a-5p in bone metastatic PCa tissues. In turn, miR-33a-5p formed a double negative feedback loop with ZEB1 in target-independent manner, which was dependent on TGF-β signaling. Finally, the clinical negative correlations of miR-33a-5p with ZEB1 expression and TGF-β signaling activity were demonstrated in PCa tissues and primary PCa cells. Conclusion: Our findings elucidated that copy number gains of ZEB1-triggered a TGF-β signaling-dependent miR-33a-5p-mediated negative feedback loop was highly relevant to the bone metastasis of PCa.

Bone metastases are a frequent complication of breast cancer, and there has been little progress in the treatment of breast cancer patients with bone metastases. The cytotoxicity of selenium donors, including organic selenium and selenium nanoparticles (SeNPs), to cancer cells has been reported previously, but their relationship with bone metastases progression is not fully clear yet. In this study, multicenter clinical exploration was conducted to obtain dietary selenium intakes of breast cancer patients with or without bone metastasis, to study the relationship between selenium and breast cancer prognosis and bone metastasis. We found that dietary selenium intakes were significantly lower in breast cancer patients with bone metastasis, comparing with the non-bone metastasis cases. Selenium lower group of bone metastasis breast cancer patients had worse prognosis, whereas the daily selenium intakes could not predict the prognosis of breast cancer patients without bone metastasis. Subsequently, we study the regulatory role of selenium donors on bone metastasis at the cellular level, by challenging the cells with SeNPs. SeNPs showed potent cytotoxicity in breast cancer cells, no matter whether they were primary or bone-metastatic. SeNPs treated cancer cell inhibited the survival and differentiation of osteoclast progenitor cells. At the molecular level, we demonstrated that IL-6 partially mediated osteoclastogenesis suppression by SeNPs. These results provide a new way for biomarkers or drug development to treat and even prevent bone metastases of breast cancer by using selenium donors.

Background: Cancer stem cells (CSCs) are biologically characterized by self-renewal, multi-directional differentiation and infinite proliferation, inducing anti-tumor drug resistance and metastasis. In the present study, we attempted to depict the baseline landscape of CSC-mediated biological properties, knowing that it is vital for tumor evolution, anti-tumor drug selection and drug resistance against fatal malignancy. Methods: We performed single-cell RNA sequencing (scRNA-seq) analysis in 15208 cells from a pair of primary and metastatic sites of collecting duct renal cell carcinoma (CDRCC). Cell subpopulations were identified and characterized by t-SNE, RNA velocity, monocle and other computational methods. Statistical analysis of all single-cell sequencing data was performed in R and Python. Results: A CSC population of 1068 cells was identified and characterized, showing excellent differentiation and self-renewal properties. These CSCs positioned as a center of the differentiation process and transformed into CDRCC primary and metastatic cells in spatial and temporal order, and played a pivotal role in promoting the bone destruction process with a positive feedback loop in the bone metastasis microenvironment. In addition, CSC-specific marker genes BIRC5, PTTG1, CENPF and CDKN3 were observed to be correlated with poor prognosis of CDRCC. Finally, we pinpointed that PARP, PIGF, HDAC2, and FGFR inhibitors for effectively targeting CSCs may be the potential therapeutic strategies for CDRCC. Conclusion: The results of the present study may shed new light on the identification of CSCs, and help further understand the mechanism underlying drug resistance, differentiation and metastasis in human CDRCC.

Purpose: We evaluated the imaging and clinical features for discriminating the possibility of metastasis among FDG-avid bone lesions in 18F-FDG PET/CT in patients who have received bone biopsy. Methods: The retrospective study included patients who underwent both 18F-FDG PET/CT and bone biopsy for FDG-avid bone lesions. Bone lesions maximum standardized uptake value (SUVmax), CT findings, alongside with common clinical features were analyzed. Results: From the 338 patients enrolled in the final study, all of them were received bone biopsy. Biopsies confirm metastasis in 256 cases (75.74%) and benign tissue in 82 cases (24.26%). Metastasis group had higher bone SUVmax than benign group (median 7.9 vs 4.5, p

// Satoshi Tamada 1 , Taro Iguchi 1 , Minoru Kato 1 , Jumpei Asakawa 1 , Kazuaki Kita 1 , Sayaka Yasuda 1 , Takeshi Yamasaki 1 , Yudai Matsuoka 2 , Kazuyuki Yamaguchi 2 , Kentaro Matsumura 2 , Ishun Go 2 , Tetsuji Ohmachi 2 and Tatsuya Nakatani 1 1 Department of Urology, Osaka City University Graduate School of Medicine, Abeno-ku, Osaka 545–8585, Japan 2 Department of Urology, Bell Land General Hospital, Naka-ku, Sakai City, Osaka 599–8247, Japan Correspondence to: Satoshi Tamada, email: s-tamada@med.osaka-cu.ac.jp Keywords: castration-resistant prostate cancer; combined androgen blockade; hormone-sensitive prostate cancer; progression; survival Received: September 19, 2018 Accepted: November 26, 2018 Published: December 11, 2018 ABSTRACT Purpose: The aim of our retrospective study was to determine the time to progression to castration-resistant prostate cancer (CRPC) in prostate cancer patients who undergo combined androgen blockade (CAB), as well as their prognoses. Materials and Methods: We examined the overall survival (OS) and disease-specific survival rates, as well as the time to CRPC development, in 387 patients who were treated with CAB for prostate cancer. The disease-specific survival rate and time to CRPC were stratified by prostate-specific antigen (PSA) levels, Gleason score (GS), and presence of metastasis at diagnosis. We designated high-risk patients as those satisfying at least two of the following three criteria: extent of disease of bone metastasis grade ≥2, presence of metastasis at diagnosis, and a GS ≥8. Results: The 10- and 15-year OS rates were 74.0% and 50.4%, respectively, while the corresponding disease-specific survival rates were both 86.8%. Metastasis at diagnosis was an independent prognostic factor for disease-specific survival. The median time to CRPC development was 140.7 months. A PSA level ≥20 ng/mL, a GS ≥8, and the presence of metastasis at diagnosis were independent predictors of a shorter time to CRPC development. The 10-year disease-specific survival rate in the high-risk group was significantly lower than that in the low-risk group (approximately 74% vs. 98%), and the time to CRPC development was significantly shorter (median: 20.5 months vs. not reached). Conclusions: The time to CRPC development was shorter in high-risk prostate cancer patients with metastases. Such patients require alternative novel treatment modalities.

Emerging studies have shown that the expression of AR splice variants (ARv) lacking ligand-binding domain is associated with castrate-resistant prostate cancer (CRPC) and higher risk of tumor metastasis and recurrence. Nuclear export protein XPO1 regulates the nuclear localization of many proteins including tumor suppressor proteins. Increased XPO1 in prostate cancer is associated with a high Gleason score and bone metastasis. In this study, we found that high expression of AR splice variant 7 (AR-v7) was correlated with increased XPO1 expression. Silencing of XPO1 by RNAi or treatment with Selective Inhibitor of Nuclear Export (SINE) compounds selinexor and eltanexor (KPT-8602) down-regulated the expression of AR, AR-v7 and ARv567es at mRNA and protein levels. XPO1 silencing also inhibited the expression of AR and ARv regulators including FOXA1, Src, Vav3, MED1 and Sam68, leading to the suppression of ARv and AR target genes, UBE2C and PSA. By targeting XPO1/ARv signaling, SINE suppressed prostate cancer (PCa) growth in vitro and in vivo and potentiated the anti-cancer activity of anti-AR agents, enzalutamide and abiraterone. Therefore, XPO1 inhibition could be a novel promising agent used in combination with conventional chemotherapeutics and AR-targeted therapy for the better treatment of PCa, especially CRPC. ispartof: Oncotarget vol:9 issue:82 pages:35327-35342 ispartof: location:United States status: Published online

Objective: To evaluate the clinicopathologic characteristics of the long-time survivals and construct a clinical nomogram using the Surveilance, Epidemiology, and End Results (SEER) database. Materials and Methods: Information of patients diagnosed with M1 stage esophageal cancer from 2010-2014 was retrieved from SEER database. Patients with unknown information of AJCC TNM stage or metastatic sites or marital status or surgery or survival were excluded. Demographic and clinicopathologic characteristics were compared between LTS (long time survivals: patients who have survived for no less than 2 years) and STS (shorter time survivals: patients who have survived for less than 2 years). Cox regression analysis was performed to evaluate prognostic factors. A nomogram comprising demographic and clinicopathologic factors was established to predict 1-year survival and 2-year survival for patients with M1 diseases. Results: A total of 2981 patients from the SEER database were included for analysis. Compared with the STS, married people and patients with well differentiated tumors or oligometastatic site were more likely to be LTS. Also, LTS were associated with significantly less bone metastasis and more surgery. The OS nomogram, which had a c-index of 0.633, was based on the eleven variables: gender, age, marital status, T stage, N stage, histology, grade, number of important metastatic organs and primary surgery. Conclusions: Married patients, patients with well differentiated tumors, patients with oligometastatic site, patients without bone metastasis or liver metastasis and those who underwent surgery are associated with long time survivals. We developed a nomogram predicting 1- and 2-year OS and CSS for M1 stage esophageal cancer. The prognostic model may improve clinicians' abilities to predict individualized survival and to make treatment recommendations.

NFκB is implicated in breast cancer bone metastasis and skeletal remodelling. However, the role of IKKβ, a key component of the canonical NFκB pathway, in the regulation of breast cancer osteolytic metastasis has not been investigated. Here, we describe the cancer-specific contribution of IKKβ to bone metastasis, skeletal tumour growth and osteolysis associated with breast cancer. IKKβ is highly expressed in invasive breast tumours and its level of expression was higher in patients with bone metastasis. IKKβ overexpression in parental MDA-MD-231 breast cancer cells, promoted mammary tumour growth but failed to convey osteolytic potential to these cells in mice. In contrast, IKKβ overexpression in osteotropic sub-clones of MDA-MB-231 cells with differing osteolytic phenotypes increased incidence of bone metastasis, exacerbated osteolysis and enhanced skeletal tumour growth, whereas its knockdown was inhibitory. Functional and mechanistic studies revealed that IKKβ enhanced the ability of osteotropic MDA-MB-231 cells to migrate, increase osteoclastogenesis, and to inhibit osteoblast differentiation via a mechanism mediated, at least in part, by cytoplasmic sequestering of FoxO3a and VEGFA production. Thus, tumour-selective manipulation of IKKβ and its interaction with FoxO3a may represent a novel strategy to reduce the development of secondary breast cancer in the skeleton.

DNA damage response plays a critical role in tumor growth, but little is known about its potential role in bone metabolism. We employed selective inhibitors of Chk1 and examined their effects on the proliferation and migration of mammary tumor cells as well as the development of osteoblasts and osteoclasts. Further, using a mouse model of bone metastasis we evaluated the effects of Chk1 inhibitors on bone quality. Chk1 inhibitors blocked the proliferation, survival, and migration of tumor cells in vitro and suppressed the development of bone-resorbing osteoclasts by downregulating NFATc1. In the mouse model, Chk1 inhibitor reduced osteolytic lesions and prevented mechanical weakening of the femur and tibia. Analysis of RNA-seq expression data indicated that the observed effects were mediated through the regulation of eukaryotic translation initiation factor 2 alpha, stress to the endoplasmic reticulum, S100 proteins, and bone remodeling-linked genes. Our findings suggest that targeting Chk1 signaling without adding DNA damaging agents may protect bone from degradation while suppressing tumor growth and migration.

Highlights • Musculoskeletal sarcoma surgery involving the lower limb is associated with significant intraoperative blood loss, with more than 500 ml in 96% of patients. • Salvaged blood was processed and re-infused in 94% of patients. • An estimated one-fourth of intraoperative blood loss was returned to the patient through (Intraoperative cell salvage) ICS. • Cytological analysis of imprints from leucodepletion filters(LDF) and reinfused blood did not reveal evidence of tumour cells., Background The efficacy and safety of cell salvage for musculoskeletal sarcoma surgery have not been reported, and concerns over re-infusion of tumour cells remain. This study aims to i) describe the intra-operative blood loss and cell salvage reinfusion volumes for lower limb sarcoma and pelvic sarcoma procedures ii) and explore whether there is evidence of tumour cells in reinfused blood. Methods Retrospective analysis of 109 consecutive surgical procedures for biopsy-proven sarcoma or bone metastasis performed between 1 July 2015 and 30 October 2019. Salvaged blood was processed and reinfused when intraoperative blood loss exceeded 500 ml. Primary bone tumour (n = 86(79%)) and metastasis (n = 23(21%) constituted the study group and surgeries were classified under hemipelvectomy (n = 43(39%)), lower limb endoprosthesis replacement (LLE) (n = 50(46%)) and wide excision surgery (WE) (n = 16(15%)). Microscopic examination of imprint cytology of leuco-depletion(LD) filters, and peripheral smear examination was performed for reinfused blood. Results Median (IQR) intra-operative blood loss was 1750 (600–3000) ml for hemipelvectomy, 850 (600–1200) ml for LLE, and 1000 (550–2000) ml for WE. Salvaged blood was re-infused in 102 of 109 (94%) patients. The mean (SD) volume of re-infusion was 445(4 2 5) ml for hemipelvectomy, 206(1 3 1) ml for LLE, and 184(1 0 6) ml for WE. In total, 64 of 109 (59%) patients received an allogeneic red blood transfusion within 72 h of surgery. Cytology analysis of imprints taken from the filtered blood available in 95(87%) patients and peripheral smear examination of reinfused blood available in 32(29%) patients did not reveal evidence of tumour cells on microscopic examination of any samples. Conclusion Our study demonstrates that musculoskeletal sarcoma surgery is associated with significant blood loss, and cell salvage permits reinfusion of autologous blood in most patients. The cytological analysis did not reveal evidence of tumour cells in reinfused blood, consistent with other studies where cell salvage is used for cancer surgery.

Highlights • The incidence of ES of the bone is very low, reaching a peak in adolescence. • We assessed the patterns of DM and the prognostic factors in this patient subset. • Lung and bone are the most frequently distant metastatic sites. • Bone metastasis is an independent risk factor for inferior survival., Background Ewing sarcoma (ES) of bone is accounting for the second most common type of primary bone cancer in children and adolescents. However, the patterns of distant metastasis (DM) and the effect of the sites of DM on survival outcomes were not investigated. Aims This study aimed to investigate the patterns of DM and the prognostic factors related to outcomes in primary metastatic ES of the bone. Methods Patients who were diagnosed with primary metastatic ES between 2010 and 2018 were identified from the Surveillance, Epidemiology, and End Results database. Kaplan–Meier analysis, log-rank tests, and Cox proportional-hazards regression models were used for statistical analyses. Results We identified 277 patients in this study and 95.3% of them (n = 264) receiving chemotherapy. A total of 371 sites of DM were observed. Lung was the most common distant metastatic site (n = 182, 49.1%), followed by bone (n = 139, 37.5%), distant lymph node (n = 26, 7.0%), liver (n = 14, 3.8%), and brain (n = 10, 2.7%). Three-year cause-specific survival (CSS) was 56.1% in the entire cohort. Older age (hazard ratio [HR] 2.210, P

Highlights • BoM was prone to multiple organs metastases and had more complex aberrations. • BoM was associated with worse prognosis which cannot be salvaged by Osimertinib. • BoM was an independent prognostic factor for EGFR-TKI treatment in PFS and OS., Background Targeted therapy has been established as the standard-of-care for patients with advanced non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. Among patients with advanced lung cancer, 30–40% have bone metastases (BoM) at first diagnosis. However, little is known on the clinical characteristics and prognostic factors of BoM in patients with NSCLC harboring EGFR mutations. Methods Treatment-naive patients with advanced NSCLC harboring EGFR mutations who were prescribed tyrosine kinase inhibitors (TKIs) were screened and enrolled between June 2009 and April 2019 from West China Hospital. Patients were dichotomized according to whether they had BoM. The demographic characteristics, gene mutation status and therapeutic efficacy, including objective response rate (ORR), progression-free survival (PFS) and overall survival (OS), were collected. Results A cohort of 604 patients were enrolled. The BoM group had worse PFS (11.7 vs. 14.0 months, HR = 0.73, p = 0.00013) and OS (32.8 vs. 46.1 months, HR = 0.54, p

Bone is the most common target organ of metastasis of breast cancers. This produces considerable morbidity due to skeletal-related events, and severely reduces the quality of life. Increased osteoclast activity is implicated in breast cancer outgrowth in the bone microenvironment. Our previous observation of an anti-osteoclastic activity of hypericin, a natural plant compound, led us to investigate whether hypericin could inhibit bone metastasis and osteolysis caused by breast cancer. We find that hypericin inhibited the upregulation of osteoclasts stimulated by breast cancer cells. The activity of hypericin on osteoclasts and breast cancer-mediated osteoclastogenesis was associated with the inhibition of NFATc1 signaling pathway and attenuation of Ca2+ oscillation. Furthermore, hypericin suppresses invasion and migration in breast cancer cells, but has little effect on breast cancer-cell induced RANKL/OPG ratio in osteoblast or the expression of osteoclast-activating factors. Administration of hypericin could reduce tumor burden, osteolysis induced by direct inoculation of MDA-MB-231 cells into the bone marrow cavity of the tibia as well as metastasis of bone and improve survival in an experimental metastasis model by intracardiac injection of MDA-MB-231 breast cancer cells. Taken together, these results suggest that hypericin may be a potential natural agent for preventing and treating bone destruction in patients with bone metastasis due to breast cancer.

This study analyzed 99Tcm-MDP bone scans and investigated factors influencing early-stage castration resistance in prostate cancer (CRPC) patients with bone metastasis. We retrospectively analyzed clinical data from 92 patients with bone metastatic prostate cancer treated with maximal androgen blockade. Patients were imaged with 99Tcm-MDP bone scan to detect metastases, and prostate specific antigen (PSA) values were measured regularly. Before treatment, 464 total bone metastases were detected in the 92 patients, with pelvic bone metastases accounting for about 30.6% of the total. After combined androgen blockade treatment, median CRPC occurrence time was 23 months. A longer time to reach the lowest PSA value was an independent predictor of early-onset CRPC (occurrence 8, higher PSA values after treatment, and shorter times to reach the lowest PSA value had poorer responses to combined androgen blockade treatment.

// Yun Ye 1, 2, * , Su-Liang Li 2, * , Yue-Yun Ma 1 , Yan-Jun Diao 1 , Liu Yang 1 , Ming-Quan Su 1 , Zhuo Li 2 , Yang Ji 3 , Juan Wang 1 , Lin Lei 1 , Wei-Xiao Fan 1 , La-Xiu Li 1 , Yi Xu 1 and Xiao-Ke Hao 1 1 Department of Laboratory Medicine, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi 710032, China 2 Department of Clinical Laboratory, The First Affiliated Hospital of Xi’an Medical University, Xi’an, Shaanxi 710077, China 3 Department of Radiology, The First Affiliated Hospital of Xi’an Medical University, Xi’an, Shaanxi 710077, China * These authors have contributed equally to this study Correspondence to: Xiao-Ke Hao, email: haoxkg@126.com Keywords: exosome; miR-141-3p; DLC1; p38MAPK; osteoblast activity Received: May 07, 2017 Accepted: September 05, 2017 Published: October 24, 2017 ABSTRACT Exosomes from cancer cells, which contain microRNA and reach metastasis loci prior to cancer cells, stimulate the formation of a metastatic microenvironment. Previous studies have shown that exosomal miR-141-3p is associated with metastatic prostate cancer (PCa). However, the role and regulatory mechanism of miR-141-3p in the microenvironment of bone metastases require further study. In this study, we performed a series of experiments in vivo and in vitro to determine whether exosomal miR-141-3p from MDA PCa 2b cells regulates osteoblast activity to promote osteoblastic metastasis. We demonstrate that extracts obtained from cell culture supernatants contained exosomes and that miR-141-3p levels were significantly higher in MDA PCa 2b cell exosomes. Via confocal imaging, numerous MDA PCa 2b exosomes were observed to enter osteoblasts, and miR-141-3p was transferred to osteoblasts through MDA PCa 2b exosomes in vitro . Exosomal miR-141-3p from MDA PCa 2b promoted osteoblast activity and increased osteoprotegerin OPG expression. miR-141-3p suppressed the protein levels of the target gene DLC1, indicating its functional significance in activating the p38MAPK pathway. In animal experiments, exosomal miR-141-3p had bone-target specificity and promoted osteoblast activity. Mice injected with miR-141-3p-mimics exosomes developed apparent osteoblastic bone metastasis. Exosomal miR-141-3p from MDA PCa 2b cells promoted osteoblast activity and regulated the microenvironment of bone metastases, which plays an important role in the formation of bone metastases and osteogenesis damage in PCa. Clarifying the specific mechanism of bone metastasis will help generate new possibilities for the treatment of PCa.

// Patricia Juarez 1, 2 , Pierrick G.J. Fournier 1, 2 , Khalid S. Mohammad 1 , Ryan C. McKenna 3 , Holly W. Davis 3 , Xiang H. Peng 1 , Maria Niewolna 1 , Alain Mauviel 4, 5, 6, 7 John M. Chirgwin 1 and Theresa A. Guise 1 1 Division of Endocrinology, Department of Medicine, Indiana University Purdue University at Indianapolis, Indiana, USA 2 Ensenada Center for Scientific Research and Higher Education, Ensenada, Mexico 3 University of Virginia, Charlottesville, Virginia, USA 4 Institute Curie, Orsay, France 5 INSERM U1021, Orsay, France 6 CNRS UMR3347, Orsay, France 7 Universite Paris XI, Orsay, France Correspondence to: Theresa A. Guise, email: tguise@iu.edu Keywords: halofuginone, zoledronic acid, bone metastases, TGF-β, BMP Received: June 21, 2017 Accepted: August 04, 2017 Published: September 23, 2017 ABSTRACT More efficient therapies that target multiple molecular mechanisms are needed for the treatment of incurable bone metastases. Halofuginone is a plant alkaloid-derivative with antiangiogenic and antiproliferative effects. Here we demonstrate that halofuginone is an effective therapy for the treatment of bone metastases, through multiple actions that include inhibition of TGFβ and BMP-signaling. Halofuginone blocked TGF-β-signaling in MDA-MB-231 and PC3 cells showed by inhibition of TGF-β-induced Smad-reporter, phosphorylation of Smad-proteins, and expression of TGF-β-regulated metastatic genes. Halofuginone increased inhibitory Smad7-mRNA and reduced TGF-β-receptor II protein. Proline supplementation but not Smad7-knockdown reversed halofuginone-inhibition of TGF-β-signaling. Halofuginone also decreased BMP-signaling. Treatment of MDA-MB-231 and PC3 cells with halofuginone reduced the BMP-Smad-reporter (BRE) 4 , Smad1/5/8-phosphorylation and mRNA of the BMP-regulated gene Id-1. Halofuginone decreased immunostaining of phospho-Smad2/3 and phospho-Smad1/5/8 in cancer cells in vivo . Furthermore, halofuginone decreased tumor-take and growth of orthotopic-tumors. Mice with breast or prostate bone metastases treated with halofuginone had significantly less osteolysis than control mice. Combined treatment with halofuginone and zoledronic-acid significantly reduced osteolytic area more than either treatment alone. Thus, halofuginone reduces breast and prostate cancer bone metastases in mice and combined with treatment currently approved by the FDA is an effective treatment for this devastating complication of breast and prostate-cancer.

Background: Bone represents one of the most common sites to which breast cancer cells metastasize. Patients experience skeletal related adverse events (pathological fractures, spinal cord compressions, and irradiation for deteriorated pain on bone) even during treatment with zoledronic acid (ZA). Therefore, we conducted a retrospective cohort study to investigate the predictive factors for symptomatic skeletal events (SSEs) in bone-metastasized breast cancer (b-MBC) patients. Methods: We retrospectively collected data on b-MBC patients treated with ZA. Patient characteristics, including age, subtype, the presence of non-bone lesions, the presence of multiple bone metastases at the commencement of ZA therapy, duration of ZA therapy, the time interval between breast cancer diagnosis and the initiation of ZA therapy, and type of systemic therapy, presence of previous SSE were analyzed using multivariable logistic regression analysis. Results: The medical records of 183 patients were reviewed and 176 eligible patients were analyzed. The median age was 59 (range, 30–87) years. Eighty-seven patients were aged ≥60 years and 89 patients were aged < 60 years. The proportions of patients with estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2-positive disease were 81.8%, 63.1%, and 17.6%, respectively. Fifty-three patients had bone-only MBC at the commencement of ZA therapy. SSEs were observed in 42 patients. In the multivariable logistic regression analysis, bone-only MBC but not a breast cancer subtype was an independent risk factor for an SSE during ZA therapy (odds ratio: 3.878, 95% confidence interval: 1.647–9.481; p = 0.002). Conclusions: Bone-only MBC patients are more likely to experience an SSE even after treatment with ZA.

// Kai-Jie Yu 1, 5, 6, * , Jeffrey K. Li 1, * , Yu-Chen Lee 1, * , Guoyu Yu 1 , Song-Chang Lin 1 , Tianhong Pan 7 , Robert L. Satcher 7 , Mark A. Titus 2 , Li-Yuan Yu-Lee 4 , Wen Hui Weng 6 , Gary E. Gallick 2, 3 and Sue-Hwa Lin 1, 2, 3 1 Department of Translational Molecular Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA 2 Department of Genitourinary Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA 3 The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas, USA 4 Department of Medicine, Baylor College of Medicine, Houston, Texas, USA 5 Division of Urology, Department of Surgery, Chang Gung Memorial Hospital at Linkou, Chang Gung University College of Medicine, Taoyuan, Taiwan 6 Department of Chemical Engineering and Biotechnology and Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of Technology, Taipei, Taiwan 7 Department of Orthopedic Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA * Authors have contributed equally to this work Correspondence to: Sue-Hwa Lin, email: slin@mdanderson.org Keywords: cabozantinib, osteoblast, secretome, anchorage-independent growth, migration Abbreviations: CM: conditioned medium; PCa: prostate cancer; PMOs: primary mouse osteoblasts; real-time RT-PCR: reverse transcription followed with real-time polymerase chain reaction; ELISA: enzyme-linked immunosorbent assay Received: May 25, 2017 Accepted: July 14, 2017 Published: August 24, 2017 ABSTRACT Therapies that target cancer cells may have unexpected effects on the tumor microenvironment that affects therapy outcomes or render therapy resistance. Prostate cancer (PCa) bone metastasis is uniquely associated with osteoblastic bone lesions and treatment with cabozantinib, a VEGFR-2 and MET inhibitor, leads to a reduction in number and/or intensity of lesions on bone scans. However, resistance to cabozantinib therapy inevitably occurs. We examined the effect of cabozantinib on osteoblast differentiation and secretion in the context of therapy resistance. We showed that primary mouse osteoblasts express VEGFR2 and MET and cabozantinib treatment decreased osteoblast proliferation but enhanced their differentiation. A genome-wide analysis of transcriptional responses of osteoblasts to cabozantinib identified a set of genes accounting for inhibition of proliferation and stimulation of differentiation, and a spectrum of secreted proteins induced by cabozantinib, including pappalysin, IGFBP2, WNT 16, and DKK1. We determined that these proteins were upregulated in the conditioned medium of cabozantinib-treated osteoblasts (CBZ-CM) compared to control CM. Treatment of C4-2B4 or PC3-mm2 PCa cells with CBZ-CM increased the anchorage-independent growth and migration of these PCa cells compared to cells treated with control CM. These results suggest that the effect of cabozantinib on the tumor microenvironment may increase tumor cell survival and cause therapy resistance.

We analyzed 428 femoral metastases initially treated with radiotherapy between 2002 and 2011 to clarify the clinical details of post-irradiation fractures of femoral metastasis. Patients included 161 men and 167 women, with a mean age of 62 years. Fracture incidence, fracture site, fracture risk based on X-ray images before radiotherapy, and interval from completion of radiotherapy to fracture occurrence were assessed. In addition, 24 pathological specimens obtained during 27 surgeries for these fractures were examined. Fractures occurred in 7.7% of 428 femoral metastases (total 33: 28 actual fractures and five virtual fractures with progressive pain and bone destruction). The fracture rate was 7.8% in the proximal femur and 1.5% in the shaft (P = 0.001). Fractures occurred a median of 4.4 months after radiotherapy, with 39.4% occurring within 3 months and 63.6% within 6 months. Among femurs with high fracture risk according to Harrington’s criteria or Mirels’ score, the fracture rate was 13.9% and 11.8%, respectively. Viable tumor cells were detected in all five patients with painful virtual fracture, in 85.7% of femurs with actual fractures that occurred within 3 months, and in only 25.0% of actual fractures occurring after 3 months. Post-irradiation fractures of femoral metastasis most frequently occurred within 3 months after radiotherapy, and were more common in the peritrochanteric area than in the shaft. Radiological evidence of impending fracture did not correlate with a high fracture rate. Actual fractures occurring after more than 3 months were likely caused by post-irradiation fragility of the femur, without viable tumor cells.

18F-Fluciclovine (trans-1-amino-3-18F-fluorocyclobutanecarboxylic acid; anti-18F-FACBC) is a positron emission tomography (PET) tracer for diagnosing cancers (e.g., prostate and breast cancer). The most frequent metastatic organ of these cancers is bone. Fluciclovine-PET can visualize bony lesions in clinical practice; however, such lesions have not been described histologically. Methods: We investigated the potential of 14C-fluciclovine in aiding the visualization of osteolytic and osteoblastic bone metastases (with histological analyses), compared with 3H-2-deoxy-2-fluoro-D-glucose (3H-FDG), 3H-choline chloride (3H-choline), and 99mTc-hydroxymethylene diphosphonate (99mTc-HMDP) by using triple-tracer autoradiography in rat breast cancer osteolytic (on day 12 ± 1 postinjection of MRMT-1) and prostate cancer osteoblastic (on day 20 ± 3 postinjection of AT6.1) metastatic models. Results: The distribution patterns of 14C-fluciclovine, 3H-FDG, and 3H-choline, but not 99mTc-HMDP, were similar in both models, and the lesions where these tracers accumulated were, histologically, typical osteolytic and osteoblastic lesions. 99mTc-HMDP accumulated mostly in osteoblastic lesions. 14C-fluciclovine could visualize the osteolytic lesions as early as day 6 postinjection of MRMT-1. However, differential distributions in 14C-fluciclovine and 3H-FDG existed, based on histological differences: low 14C-fluciclovine and high 3H-FDG accumulation in osteolytic lesions with inflammation. In the osteoblastic metastatic model, visualization of osteoblastic lesions with 14C-fluciclovine was not clear, yet clearer than with 3H-FDG. Although half of the osteoblastic lesions with 14C-fluciclovine accumulation showed negligible 3H-choline accumulation in comparison, they were histologically similar to lesions with marked 14C-fluciclovine and 3H-choline accumulation. Conclusion: These results suggest that fluciclovine-PET can visualize true osteolytic and osteoblastic bone metastatic lesions.

// Juanjuan Li 1, * , Yue Xia 2, * , Qi Wu 1 , Shan Zhu 1 , Chuang Chen 1 , Wen Yang 1 , Wen Wei 1 and Shengrong Sun 1 1 Department of Breast and Thyroid Surgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, P. R. China 2 Department of Urology, Renmin Hospital of Wuhan University, Wuhan, Hubei, P. R. China * These authors have contributed equally to this work Correspondence to: Shengrong Sun, email: sun137@sina.com Keywords: outcomes, inflammatory breast cancer, molecular subtypes, SEER program Received: January 20, 2017 Accepted: March 24, 2017 Published: April 19, 2017 ABSTRACT Background: The aim of this study was to evaluate the outcomes of patients with inflammatory breast cancer (IBC), with emphasis on the role of molecular subtypes and radiotherapy. Methods: A retrospective cohort study to investigate overall survival (OS) and breast cancer-specific mortality (BCSM) in patients with IBC was conducted using data obtained by the Surveillance, Epidemiology, and End Results (SEER) program from 2010–2013. Cox multivariate regression was used to calculate the adjusted Hazard Ratios (aHR). Results: 403 patients were eligible for this study. Patients in the group with hormone receptors (HR)+/HER2- subtype had an OS of 79.6% compared with 89.0 % in the group with (HR)+/HER2+ subtype and 76.8% in the HR-/HER2+ group and 62.9% in the triple-negative (TN) group. BCSM was 16.3% for the HR+/HER2- group, 9.8% for the HR+/HER2+ group, 21.7% for the HR-/HER2+ group, and 30.5% for the TN group. For distant metastases, the results showed that there was a high probability of bone metastasis in HR-positive groups, brain and liver metastasis in HER2-positive groups, and lung metastasis in the TN group. Multivariate analysis demonstrated that estrogen receptor and HER2 positivity were associated with better survival and that the TN subtype had a poorer OS and BCSM compared with other subtypes (P

// Paul A. Stewart 1, * , Zahraa I. Khamis 1, 4, * , Haiyen E. Zhau 2, * , Peng Duan 2 , Quanlin Li 2 , Leland W.K. Chung 2 and Qing-Xiang Amy Sang 1, 3 1 Department of Chemistry & Biochemistry, Florida State University, Tallahassee, FL, United States of America 2 Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States of America 3 Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, United States of America 4 Laboratory of Cancer Biology and Molecular Immunology, Department of Biochemistry, Faculty of Sciences, Lebanese University, Beirut, Lebanon * These authors have contributed equally to this work Correspondence to: Qing-Xiang Amy Sang, email: qxsang@chem.fsu.edu Haiyen E. Zhau, email: haiyen.zhau@cshs.org Keywords: epithelial-to-mesenchymal transition, minichromosome maintenance complex proteins, metastasis, androgen receptor, proteomics Received: September 06, 2016 Accepted: March 08, 2017 Published: April 05, 2017 ABSTRACT Metastasis is often associated with epithelial-to-mesenchymal transition (EMT). To understand the molecular mechanisms of this process, we conducted proteomic analysis of androgen-repressed cancer of the prostate (ARCaP), an experimental model of metastatic human prostate cancer. The protein signatures of epithelial (ARCaP E ) and mesenchymal (ARCaP M ) cells were consistent with their phenotypes. Importantly, the expression of mini-chromosome maintenance 3 (MCM3) protein, a crucial subunit of DNA helicase, was significantly higher in ARCaP M cells than that of ARCaP E cells. This increased MCM3 protein expression level was verified using Western blot analysis of the ARCaP cell lineages. Furthermore, immunohistochemical analysis of MCM3 protein levels in human prostate tissue specimens showed elevated expression in bone metastasis and advanced human prostate cancer tissue samples. Subcutaneous injection experiments using ARCaP E and ARCaP M cells in a mouse model also revealed increased MCM3 protein levels in mesenchymal-derived tumors. This study identifies MCM3 as an upregulated molecule in mesenchymal phenotype of human prostate cancer cells and advanced human prostate cancer specimens, suggesting MCM3 may be a new potential drug target for prostate cancer treatment.

Bone is one of the most preferred sites of metastasis in lung cancer. Currently, bisphosphonates and denosumab are major agents for controlling tumor-associated skeletal-related events (SREs). However, both bisphosphonates and denosumab significantly increase the risk for jaw osteonecrosis. Statins, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors and the most frequently prescribed cholesterol-lowering agents, have been reported to inhibit tumor progression and induce autophagy in cancer cells. However, the effects of statin and role of autophagy by statin on bone metastasis are unknown. In this study, we report that fluvastatin effectively prevented lung adenocarcinoma bone metastasis in a nude mouse model. We further reveal that fluvastatin-induced anti-bone metastatic property was largely dependent on its ability to induce autophagy in lung adenocarcinoma cells. Atg5 or Atg7 deletion, or 3-methyadenine (3-MA) or Bafilomycin A1 (Baf A1) treatment prevented the fluvastatin-induced suppression of bone metastasis. Furthermore, we reveal that fluvastatin stimulation increased the nuclear p53 expression, and fluvastatin-induced autophagy and anti-bone metastatic activity were mostly dependent on p53., Highlights • Fluvastatin effectively prevents lung adenocarcinoma bone metastasis in a nude mouse model. • Fluvastatin-induced anti-bone metastatic property was largely dependent on its ability to induce autophagy. • Fluvastatin-induced autophagy and anti-bone metastatic activity are mediated by p53. Statins, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, are most frequently prescribed cholesterol-lowering agent with minimal side effects. In this study, we present a novel function of statins in suppressing lung adenocarcinoma bone metastasis, and this function is dependent on statin-induced autophagy. Currently, there is no cure for bone metastasis, and the current treatment options using anti-bone metastatic agents have negative side effects. For example, bisphosphonates or denosumab treatments reduce tumor-associated skeletal-related events, but simultaneously increase the risk of the osteonecrosis in the jaw. As a possible therapeutic treatment option, fluvastatin is promising to cancer patients with a high risk of bone metastasis.

// Cedric Boudot 1, * , Lucie Henaut 1, * , Ursula Thiem 1 , Sandra Geraci 2 , Mariangela Galante 1 , Paulo Saldanha 1 , Zuzana Saidak 1 , Isabelle Six 1 , Philippe Clezardin 2 , Said Kamel 1 and Romuald Mentaverri 1 1 Inserm U1088, Centre Universitaire de Recherche en Sante, Universite de Picardie Jules Verne, Amiens, France 2 Inserm UMR 1033, LYOS, Lyon, France * These authors have contributed equally to this work Correspondence to: Said Kamel, email: said.kamel@u-picardie.fr Keywords: bone metastasis, breast cancer, calcium-sensing receptor, epiregulin, osteolysis Received: July 15, 2016 Accepted: March 14, 2017 Published: April 10, 2017 ABSTRACT Introduction and Aims: Osteolytic bone metastases are observed in advanced cases of breast cancer. In vitro data suggest that the activity of the calcium-sensing receptor (CaSR) expressed by metastatic cells could potentiate their osteolytic potential. This study aimed to demonstrate in vivo the involvement of the CaSR in breast cancer cells osteolytic potential and to identify potential targets linked to CaSR activity. Methods and Results: MDA-MB-231 stably transfected with plasmids containing either a full-length wild-type CaSR (CaSR-WT), or a functionally inactive dominant negative mutant (CaSR-DN) or an empty vector (EV) were intratibially injected into Balb/c-Nude mice. X-ray analysis performed 19 days after injection showed a dramatic increase of osteolytic lesions in mice injected with CaSR-WT-transfected cells as compared to mice injected with EV- or CaSR-DN-transfected cells. This was associated with decreased BV/TV ratio and increased tumor burden. Epiregulin, an EGF-like ligand, was identified by a DNA microarray as a possible candidate involved in CaSR-mediated osteolysis. Indeed, in vitro , CaSR overexpression increased both epiregulin expression and secretion as compared to EV- or CaSR-DN-transfected cells. Increased epiregulin expression was also detected in osteolytic bone lesions from mice injected with CaSR-WT-transfected MDA-MB-231. In vitro , exposure of osteoblastic cells (HOB and SaOS2) to exogenous epiregulin significantly decreased OPG mRNA expression. Exposure of osteoblastic cells to conditioned media prepared from CaSR-WT-transfected cells also decreased OPG expression. This effect was partially blocked after addition of an anti-epiregulin antibody. Conclusions: Overexpression of a functional CaSR in metastatic breast cancer cells dramatically amplifies their osteolytic potential through epiregulin-mediated OPG downregulation.

// Qi Wu 1, * , Juanjuan Li 1, * , Shan Zhu 1 , Juan Wu 2 , Chuang Chen 1 , Qian Liu 1 , Wen Wei 1 , Yimin Zhang 1 , Shengrong Sun 1 1 Department of Breast and Thyroid Surgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, P. R. China 2 Department of Pathology, Renmin Hospital of Wuhan University, Wuhan, Hubei, P. R. China * These authors contributed equally to this work Correspondence to: Shengrong Sun, email: sun137@sina.com Yimin Zhang, email: dryiminzhang@163.com Keywords: breast cancer subtypes, distant metastases, SEER Received: November 01, 2016 Accepted: February 20, 2017 Published: March 02, 2017 ABSTRACT Background and Aims: This study aimed to access possible relationships between breast cancer subtypes and sites of distant metastasis in breast cancer. Results: A total of 243,896 patients, including 226,451 cases in control groups were identified. Bone metastasis was found in 8848 cases, compared with 1,000 brain metastasis cases, 3434 liver metastasis cases and 4167 lung metastasis cases. Patients with all subtypes were most prone to bone metastases, the incidence of bone metastasis in HR+/HER2+ subtype was up to 5.1 %. Further, HR−/HER2+ subtype patients had a higher probability of brain (OR = 1.978) metastasis compared to HR+/HER2− subtype patients. In addition, liver metastasis was more frequently observed in the HER2 positive subtypes compared with HER2 negative subtypes. Patients with TN primarily presented lung metastasis, but it made no difference in the probability of lung metastases of all subtypes. Materials and Methods: Using the 2010–2013 Surveillance, Epidemiology, and End Results Program(SEER) data, a retrospective, population-based cohort study to investigate tumor subtypes-specific differences in the sites of distant metastasis. Metastatic patterns information was provided for bone, brain, liver and lung. The breast cancer was classified into four subtypes: hormone receptor (HR) +/ human epidermal growth factor receptor 2 (HER2) −, HR+/HER2+, HR−/HER2+ and triple negative (TN). Conclusions: The pathological subtypes of breast cancer are clearly different in metastatic behavior with regard to the sites of distant metastasis, emphasizing that this knowledge may help to determine the appropriate strategy for follow-up and guide personalized medicine.

// Trupti Trivedi 1, 2 , Yu Zheng 1 , Pierrick G.J. Fournier 2, 5 , Sreemala Murthy 2 , Sutha John 2 , Suzanne Schillo 1 , Colin R. Dunstan 3 , Khalid S. Mohammad 2 , Hong Zhou 1 , Markus J. Seibel 1, 4 , Theresa A. Guise 2 1 Bone Research Program, ANZAC Research Institute, University of Sydney, Sydney, Australia 2 Division of Endocrinology, Department of Medicine, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana, USA 3 Department of Biomedical Engineering, University of Sydney, Sydney, Australia 4 Department of Endocrinology and Metabolism, Concord Hospital, Concord, Sydney, Australia 5 Biomedical Innovation Department, Scientific Research and High Education Center from Ensenada (CICESE), Ensenada, Baja California, Mexico Correspondence to: Theresa A. Guise, email: tguise@iu.edu Markus J. Seibel, email: markus.seibel@sydney.edu.au Keywords: breast cancer, vitamin D, vitamin D receptor, ligand independent, bone metastasis Received: November 04, 2016 Accepted: February 15, 2017 Published: March 01, 2017 ABSTRACT Vitamin D has pleiotropic effects on multiple tissues, including malignant tumors. Vitamin D inhibits breast cancer growth through activation of the vitamin D receptor (VDR) and via classical nuclear signaling pathways. Here, we demonstrate that the VDR can also function in the absence of its ligand to control behaviour of human breast cancer cells both outside and within the bone microenvironment. Stable shRNA expression was used to knock down VDR expression in MCF-7 cells, generating two VDR knockdown clonal lines. In ligand-free culture, knockdown of VDR in MCF-7 cells significantly reduced proliferation and increased apoptosis, suggesting that the VDR plays a ligand-independent role in cancer cell growth. Implantation of these VDR knockdown cells into the mammary fat pad of nude mice resulted in reduced tumor growth in vivo compared with controls. In the intra-tibial xenograft model, VDR knockdown greatly reduced the ability of the cells to form tumors in the bone microenvironment. The in vitro growth of VDR knockdown cells was rescued by the expression of a mutant form of VDR which is unable to translocate to the nucleus and hence accumulates in the cytoplasm. Thus, our data indicate that in the absence of ligand, the VDR promotes breast cancer growth both in vitro and in vivo and that cytoplasmic accumulation of VDR is sufficient to produce this effect in vitro . This new mechanism of VDR action in breast cancer cells contrasts the known anti-proliferative nuclear actions of the VDR-vitamin D ligand complex.

// Jiang Wang 1 , Hongbo You 1 , Jun Qi 1 , Caihong Yang 1 , Ye Ren 1 , Hao Cheng 1 1 Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, P.R.China Correspondence to: Ye Ren, email: renye007@qq.com Hao Cheng, email: hcheng77@yahoo.com Keywords: RCC bone metastasis, stress-induced phosphoprotein 1(STIP1), STIP1-ALK2-SMAD1/5 signaling, STIP1-prion-ERK1/2 signaling, tumor microenvironment Received: May 07, 2016 Accepted: January 04, 2017 Published: February 09, 2017 ABSTRACT Bone metastases are responsible for some of the most devastating complications of renal cell carcinoma (RCC). However, pro-metastatic factors leading to the highly osteolytic characteristics of RCC bone metastasis have barely been explored. We previously developed novel bone-seeking RCC cell lines by the in vivo selection strategy and performed a comparative proteome analysis on their total cell lysate. Here, we focused on STIP1 (stress-induced phosphoprotein 1), the high up-regulated protein in the bone-seeking cells, and explored its clinical relevance and functions in RCC bone metastasis. We observed high levels of both intracellular and extracellular STIP1 protein in bone metastatic tissue samples. Elevated STIP1 mRNA in the primary RCC tumors remarkably correlated with worse clinical outcomes. Furthermore, both human recombinant STIP1 protein and anti-STIP1 neutralizing antibody were used in the functional studies. We found that 1) STIP1 protein on the extracellular surface of tumor cells promoted the proliferation and migration/invasion of RCC tumor cells through the autocrine STIP1-ALK2-SMAD1/5 pathway; and 2) STIP1 protein secreted into the extracellular tumor stromal area, promoted the differentiation of osteoclasts through the paracrine STIP1-PrPc-ERK1/2 pathway. Increased cathepsin K (CTSK), the key enzyme secreted by osteoclasts to degrade collagen and other matrix proteins during bone resorption was further detected in the differentiated osteoclasts. These results provide evidence of the great potential of STIP1 as a novel biomarker and therapeutic target in RCC bone metastasis.

Background : The bones are the most common site of distant metastasis in nasopharyngeal carcinoma (NPC). Few prognostic markers are available to guide treatment and sub-classify patients with bone metastasis. We aimed to identify the prognostic value of pretreatment serum alkaline phosphatase (ALP) and plasma Epstein-Barr virus DNA (EBV DNA) in patients with bone-only metastasis. Methods : A total of 272 patients who developed bone-only metastases after therapy were retrospectively analyzed. Patients were categorized according to pretreatment serum ALP (< or ≥ 110 U/L) and pretreatment plasma EBV DNA (< or ≥ 6,750 copies ml-1). Univariate and multivariate analyses of clinical variables were performed using Cox proportional hazards regression models. Overall survival (OS) was analyzed using the Kaplan-Meier method and compared using the log-rank test. Results : Median OS for the cohort was 34.06 months (range, 2.53-143.87 months). Multivariate Cox proportional hazard analysis verified pretreatment serum ALP and pretreatment plasma EBV DNA were independent prognostic factors for OS. In stratified survival analysis of patients with elevated pretreatment serum ALP and/or plasma EBV DNA, delivery of radiotherapy (RT) to bone metastases provided a significant OS benefit compared to other therapeutic methods (P < 0.05). Conclusions : This study demonstrates two important points: firstly, pretreatment serum ALP and plasma EBV DNA have prognostic value at the first diagnosis of bone-only metastasis in NPC. Secondly, radiotherapy of bone metastasis improves the prognosis of patients with elevated pretreatment serum ALP and plasma EBV DNA.

Purpose : To evaluate the outcomes of high-risk prostate cancer patients treated with biologically effective dose (BED) ≥ 220 Gy of high-dose radiotherapy, using low-dose-rate (LDR) brachytherapy in combination with external beam radiotherapy (EBRT) and short-term androgen deprivation therapy (ADT). Material and methods : From 2005 to 2013, a total of 143 patients with high-risk prostate cancer were treated by radiotherapy of BED ≥ 220 Gy with a combination of LDR brachytherapy, EBRT, and androgen deprivation therapy (ADT). The high-risk patients in the present study included both high-risk and very high-risk prostate cancer. The number of high-risk features were: 60 patients with 1 high-risk factor (42%), 61 patients with 2 high-risk factors (43%), and 22 patients with 3 high-risk factors (15%) including five N1 disease. External beam radiotherapy fields included prostate and seminal vesicles only or whole pelvis depending on the extension of the disease. Biochemical failure was defined by the Phoenix definition. Results : Six patients developed biochemical failure, thus providing a 5-year actual biochemical failure-free survival (BFFS) rate of 95.2%. Biochemical failure was observed exclusively in cases with distant metastasis in the present study. All six patients with biochemical relapse had clinical failure due to bone metastasis, thus yielding a 5-year freedom from clinical failure (FFCF) rate of 93.0%. None of the cases with N1 disease experienced biochemical failure. We observed four deaths, including one death from prostate cancer, therefore yielding a cause-specific survival (CSS) rate of 97.2%, and an overall survival (OS) rate of 95.5%. Conclusions : High-dose (BED ≥ 220 Gy) radiotherapy by LDR in combination with EBRT has shown an excellent outcome on BFFS in high-risk and very high-risk cancer, although causal relationship between BED and BFFS remain to be explained further.

Background Bone metastases are common and devastating to cancer patients. Existing treatments do not specifically target the disease sites and are therefore ineffective and systemically toxic. Here we present a new strategy to treat bone metastasis by targeting both the cancer cells (“the seed”), and their surrounding niche (“the soil”), using stem cells engineered to home to the bone metastatic niche and to maximise local delivery of multiple therapeutic factors. Methods We used mesenchymal stem cells engineered using mRNA to simultaneously express P-selectin glycoprotein ligand-1 (PSGL-1)/Sialyl-Lewis X (SLEX) (homing factors), and modified versions of cytosine deaminase (CD) and osteoprotegerin (OPG) (therapeutic factors) to target and treat breast cancer bone metastases in two mouse models, a xenograft intratibial model and a syngeneic model of spontaneous bone metastasis. Findings We first confirmed that MSC engineered using mRNA produced functional proteins (PSGL-1/SLEX, CD and OPG) using various in vitro assays. We then demonstrated that mRNA-engineered MSC exhibit enhanced homing to the bone metastatic niche likely through interactions between PSGL-1/SLEX and P-selectin expressed on tumour vasculature. In both the xenograft intratibial model and syngeneic model of spontaneous bone metastasis, engineered MSC can effectively kill tumour cells and preserve bone integrity. The engineered MSC also exhibited minimal toxicity in vivo, compared to its non-targeted chemotherapy counterpart (5-fluorouracil). Interpretation Our combinatorial targeting of both the cancer cells and the niche represents a simple, safe and effective way to treat metastatic bone diseases, otherwise difficult to manage with existing strategies. It can also be applied to other cell types (e.g., T cells) and cargos (e.g., genome editing components) to treat a broad range of cancer and other complex diseases. Fund National Institutes of Health, National Cancer Institute of the National Institutes of Health, Department of Defense, California Institute of Regenerative Medicine, National Science Foundation, Baylx Inc., and Fondation ARC pour la recherche sur le cancer.