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Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can selectively induce apoptosis in cancer cells without causing damage to normal cells. However, some tumors are resistant to TRAIL monotherapy and clinical studies assessing targeted agents towards the TRAIL receptor have failed to show robust therapeutic activity. Evidence has shown that standard anti-mitotic drugs can induce synergistic apoptosis upon combination with TRAIL via cell cycle arrest. Polo like kinase-1 (PLK1) plays a critical role in different stages of cell cycle progression and mitosis. A number of investigations have demonstrated that PLK1 inhibition causes cell cycle arrest and mitotic catastrophe in non-small cell lung cancer (NSCLC), and we thus postulated that PLK1 inhibition could enhance TRAIL-induced apoptosis. We demonstrate that the combination of a TRAIL receptor agonist and a PLK1 inhibitor synergistically reduces cell viability, and strongly increases apoptosis in NSCLC cellular models. Consistent with our in vitro observations, this drug combination also significantly reduces tumor growth in vivo. Our data additionally reveal that G2/M cell cycle arrest and downregulation of Mcl-1 and signal transducer and activator of transcription 3 (STAT3) activity following PLK1 inhibition may contribute to the sensitization of TRAIL-induced apoptosis in NSCLC. Together, these data support the further exploration of combined TRAIL and PLK1 inhibition in the treatment of NSCLC.

Preoperative radiotherapy (RT) is a mainstay in the management of rectal cancer, a tumor characterized by desmoplastic stroma containing cancer-associated fibroblasts (CAF). Although CAFs are abundantly present, the effects of RT to CAF and its impact on cancer cells are unknown. We evaluated the damage responses of CAF to RT and investigated changes in colorectal cancer cell growth, transcriptome, metabolome, and kinome in response to paracrine signals emerging from irradiated CAF. RT to CAF induced DNA damage, p53 activation, cell-cycle arrest, and secretion of paracrine mediators, including insulin-like growth factor-1 (IGF1). Subsequently, RT-activated CAFs promoted survival of colorectal cancer cells, as well as a metabolic switch favoring glutamine consumption through IGF1 receptor (IGF1R) activation. RT followed by IGF1R neutralization in orthotopic colorectal cancer models reduced the number of mice with organ metastases. Activation of the downstream IGF1R mediator mTOR was significantly higher in matched (intrapatient) samples and in unmatched (interpatient) samples from rectal cancer patients after neoadjuvant chemoradiotherapy. Taken together, our data support the notion that paracrine IGF1/IGF1R signaling initiated by RT-activated CAF worsens colorectal cancer progression, establishing a preclinical rationale to target this activation loop to further improve clinical responses and patient survival. Significance: These findings reveal that paracrine IGF1/IGF1R signaling promotes colorectal cancer progression, establishing a preclinical rationale to target this activation loop. Cancer Res; 78(3); 659–70. ©2017 AACR.

The present study aimed to investigate the orthotopic growth potential of two generally available esophageal adenocarcinoma cell lines, OE33 and OACM5 1.C, and a third in vivo selected subpopulation, OACM5 1.C SC1. One group of mice was subcutaneously injected in the hind legs. Tumor growth was measured with calipers. Another group was injected orthotopically in the distal esophageal wall through median laparotomy. Tumor development was evaluated macroscopically and confirmed microscopically. A subset of mice was evaluated with magnetic resonance imaging (MRI) to follow tumor progression. Additionally, functional cell line characteristics were evaluated in vitro (clonogenic, collagen invasion and sphere formation assays, and protein analysis of cell-cell adhesion and cytoskeletal proteins) to better understand xenograft behavior. OE33 cells were shown to be epithelial-like, whereas OACM5 1.C and OACM5 1.C SC1 were more mesenchymal-like. The three cell lines were non-invasive into native type I collagen gels. In vivo, OE33 cells led to 63.6 and 100% tumor nodules after orthotopic (n=12) and subcutaneous (n=8) injection, respectively. Adversely, OACM5 1.C cells did not lead to tumor formation after orthotopic injection (n=6) and only 50% of subcutaneous injections led to tumor nodules (n=8). However, the newly established cell line OACM5 1.C SC1 resulted in 33% tumor formation when orthotopically injected (n=6) and in 100% tumors when injected subcutaneously (n=8). The higher xenograft rate of OACM5 1.C SC1 (P

In patients with rectal prolapse is the prevalence of colorectal cancer increased, suggesting that a colorectal tumor may induce rectal prolapse. Establishment of tumor xenografts in immunodeficient mice after orthotopic inoculations of human colorectal cancer cells into the caecal wall is a widely used approach for the study of human colorectal cancer progression and preclinical evaluation of therapeutics. Remarkably, 70% of young mice carrying a COLO320DM caecal tumor showed symptoms of intussusception of the large bowel associated with intestinal lumen obstruction and rectal prolapse. The quantity of the COLO320DM bioluminescent signal of the first three weeks post-inoculation predicts prolapse in young mice. Rectal prolapse was not observed in adult mice carrying a COLO320DM caecal tumor or young mice carrying a HT29 caecal tumor. In contrast to HT29 tumors, which showed local invasion and metastasis, COLO320DM tumors demonstrated a non-invasive tumor with pushing borders without presence of metastasis. In conclusion, rectal prolapse can be linked to a non-invasive, space-occupying COLO320DM tumor in the gastrointestinal tract of young immunodeficient mice. These data reveal a model that can clarify the association of patients showing rectal prolapse with colorectal cancer., SCOPUS: ar.j, info:eu-repo/semantics/published

Background Esophageal cancer is an aggressive disease with poor survival rates. A more patient-tailored approach based on predictive biomarkers could improve outcome. We aimed to predict radiotherapy (RT) response by imaging tumor hypoxia with 18F-FAZA PET/CT in an esophageal adenocarcinoma (EAC) mouse model. Additionally, we investigated the radiosensitizing effect of the hypoxia modifier nimorazole in vitro and in vivo. Methods In vitro MTS cell proliferation assays (OACM5 1.C SC1, human EAC cell line) were performed under normoxic and hypoxic (

FHL2 is a multifunctional scaffolding protein; its expression is associated with poor prognosis in colorectal cancer. ADAM-17 is a metalloprotease implicated in ectodomain shedding. FHL2 regulates ADAM-17 plasma membrane localisation, and FHL2 deficiency leads to decreased activity of ADAM-17 in mouse macrophages. Presence and relationship of the ADAM-17/FHL2 complex with colorectal cancer progression is unknown. We studied FHL2 and ADAM-17 expression in several colon cancer cell lines by immunocytochemistry and western blot. To highlight the interaction between both molecules, we used the Duolink® kit for proximity ligation assay on SW480 cells. We also performed proximity ligation assay on biopsies and surgical specimens of colorectal adenocarcinoma and on matched normal mucosa. Furthermore, biopsies of colorectal adenoma with matched normal mucosa were selected. For quantification, pictures of the malignant, adenomatous and normal tissues were taken. Proximity ligation assay signals were quantified. Mean numbers of proximity ligation assay signals and of proximity ligation assay signals/nucleus were calculated. All cell lines showed FHL2 immunoreactivity; strongest positivity was observed in SW480 cells. ADAM-17 was expressed in all cell lines. Proximity ligation assay signals were present in SW480 cells. Quantitative analysis revealed that the interaction between FHL2 and ADAM-17 is more frequent in malignant than in normal tissue (p = 0.005). The mean number of ADAM-17/FHL2 proximity ligation assay signals was higher in colorectal adenocarcinoma than in adenoma with low-grade dysplasia (p = 0.0004). FHL2 interacts with ADAM-17 in normal, dysplastic and malignant colon epithelial cells. Colocalisation of these proteins is more frequent in malignant than in normal and dysplastic cells, suggesting a role for ADAM-17/FHL2 complex in the development of colorectal cancer.

Ovarian cancer carries a significant mortality. Since symptoms tend to be minimal, the disease is often diagnosed when peritoneal metastases are already present. The standard of care in advanced ovarian cancer consists of platinum-based chemotherapy combined with cytoreductive surgery. Unfortunately, even after optimal cytoreduction and adjuvant chemotherapy, most patients with stage III disease will develop a recurrence. Intraperitoneal administration of chemotherapy is an alternative treatment for patients with localized disease. The pharmacological and physiochemical properties of melflufen, a peptidase potentiated alkylator, raised the hypothesis that this drug could be useful in ovarian cancer and particularily against peritoneal carcinomatosis. In this study the preclinical effects of melflufen were investigated in different ovarian cancer models. Melflufen was active against ovarian cancer cell lines, primary cultures of patient-derived ovarian cancer cells, and inhibited the growth of subcutaneous A2780 ovarian cancer xenografts alone and when combined with gemcitabine or liposomal doxorubicin when administered intravenously. In addition, an intra- and subperitoneal xenograft model showed activity of intraperitoneal administered melflufen for peritoneal carcinomatosis, with minimal side effects and modest systemic exposure. In conclusion, results from this study support further investigations of melflufen for the treatment of peritoneal carcinomatosis from ovarian cancer, both for intravenous and intraperitoneal administration.

Peritoneal metastases cause cancer mortality and preclinical models are urgently needed to boost therapeutic progress. This study reports on a hybrid hydrogel-polylactic acid (PLA) scaffold that mimics the architecture of peritoneal metastases at the qualitative, quantitative and spatial level. Porous PLA scaffolds with controllable pore size, shape, and surface properties are functionalized by type I collagen hydrogel and co-seeding of cancer-associated fibroblast (CAF) increases cancer cell adhesion, recovery, and exponential growth by in situ heterocellular spheroid formation. Scaffold implantation at the peritoneal wall allows long-term follow-up (>14 weeks) and results in a time-dependent increase in vascularization, which correlates with cancer cell colonization in vivo. CAF, endothelial cells, macrophages and cancer cells show spatial and quantitative aspects as similarly observed in patient-derived peritoneal metastases. CAF provide long-term secretion of complementary paracrine factors implicated in spheroid formation in vitro as well as in recruitment and organization of host cells in vivo. In conclusion, the multifaceted heterocellular interactions that occur within peritoneal metastases are reproduced in this tissue-engineered implantable scaffold model. Citation Format: Olivier De Wever, Emiel Dejaeghere, Elly De Vlieghere. Heterocellular 3D scaffolds as biomimetic to recapitulate the tumor microenvironment of peritoneal metastases in vitro and in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5027.

Background and purpose Cancer-associated fibroblasts (CAFs) are increasingly recognised as promoters of tumour progression. It is poorly investigated whether cancer management protocols, such as neoadjuvant radio(chemo)therapy, have an impact on CAFs and, by consequence, on tumour progression. This prompted us to study the impact of neoadjuvant radio(chemo)therapy on the α-SMA/epithelial area ratio in rectal cancer, and the impact of this ratio on recurrence-free survival. Material and methods Immunohistochemistry for the CAF marker α-SMA and the proliferation marker Ki67 was performed on sections from 98 rectal cancers of which 62 had undergone neoadjuvant radio(chemo)therapy. Results Computer-assisted quantitative analysis showed that the α-SMA/neoplastic epithelial area ratio was higher after neoadjuvant therapy, and that rectal cancers with high α-SMA/epithelial area ratio had low proliferation rates. Interestingly, the α-SMA/epithelial area ratio was an adverse prognostic factor with regard to recurrence-free survival in univariate analysis. In addition, multivariate analysis showed that an α-SMA/epithelial area ratio above 1 provides an independent prognostic value associated with a poor recurrence-free survival. Conclusion These results suggest that neoadjuvant treatment has an impact on CAFs in rectal cancer. The correlation of CAFs with decreased recurrence-free survival and abundant experimental data in the literature suggest that under certain circumstances, not yet very well understood, CAFs may favour tumour progression.

Cancer progression is characterized by a complex reciprocity between neoplastic epithelium and adjacent stromal cells. In ductal carcinoma in situ (DCIS) of the breast, both reduced stromal decorin expression and myxoid stroma are correlated with increased recurrence risk. In this study, we aimed to investigate paracrine regulation of expression of decorin and related extracellular matrix (ECM) proteins in cancer-associated fibroblasts (CAFs). Transforming growth factor-β1 (TGF-β1) was identified as a competent ECM modulator, as it reduced decorin and strongly enhanced versican, biglycan and type I collagen expression. Similar but less pronounced effects were observed when fibroblasts were treated with basic fibroblast growth factor (bFGF). Despite this concerted ECM modulation, TGF-β1 and bFGF differentially regulated alpha-smooth muscle actin (α-SMA) expression, which is often proposed as a CAF-marker. Cancer cell-derived secretomes induced versican and biglycan expression in fibroblasts. Immunohistochemistry on twenty DCIS specimens showed a trend toward periductal versican overexpression in DCIS with myxoid stroma. Cancer cell adhesion was inhibited by decorin, but not by CAF-derived matrices. Cancer cells presented significantly enhanced spreading when seeded on matrices derived from TGF-β1-treated CAF. Altogether these data indicate that preinvasive cancerous lesions might modulate the composition of surrounding stroma through TGF-β1 release to obtain an invasion-permissive microenvironment.