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Epithelial‐to‐mesenchymal transition (EMT) contributes to the poor prognosis of patients with cancer by promoting distant metastasis and anti‐cancer drug resistance. Several distinct metabolic alterations have been identified as key EMT phenotypes. In the present study, we further characterize the role of transforming growth factor‐β (TGF‐β)‐induced EMT in non‐small‐cell lung cancer. Our study revealed that TGF‐β plays a role in EMT functions by upregulation of cytidine 5′‐triphosphate synthetase 1 (CTPS), a vital enzyme for CTP biosynthesis in the pyrimidine metabolic pathway. Both knockdown and enzymatic inhibition of CTPS reduced TGF‐β‐induced changes in EMT marker expression, chemoresistance and migration in vitro. Moreover, CTPS knockdown counteracted the TGF‐β‐mediated downregulation of UDP‐glucuronate, glutarate, creatine, taurine and nicotinamide. These findings indicate that CTPS plays a multifaceted role in EMT metabolism, which is crucial for the malignant transformation of cancer through EMT, and underline its potential as a promising therapeutic target for preventing drug resistance and metastasis in non‐small‐cell lung cancer.

Abstract Precision medicine has drastically changed cancer treatment strategies including KRAS-mutant cancers which have been undruggable for decades. While intrinsic or acquired treatment resistance remains unresolved in many cases, epigenome-targeted therapy may be an option to overcome. We recently discovered the effectiveness of blocking small ubiquitin-like modifier (SUMO) signaling cascade (SUMOylation) in MYC-expressing KRAS-mutant cancer cells using a SUMO-activating enzyme E inhibitor TAK-981 that results in SUMOylation inhibition. Interestingly, TAK-981 promoted the degradation of MYC via the ubiquitin–proteasome system. Moreover, combination therapy with TAK-981 and MEK inhibitor trametinib remarkably regressed xenografted KRAS-mutant tumors by accumulating DNA damage and inducing apoptosis. Whereas our recent study revealed immune-independent antitumor efficacy, we evaluated the immune responses of cancer cells and immune cells in this study. We found that TAK-981-induced MYC downregulation promoted the activation of STING followed by Stat1 and MHC class I in KRAS-mutant cancer cells. Activation of dendritic cells or T cells treated with TAK-981 was also verified by upregulated activation markers in dendritic cells or skew-toward effector-like phenotypes in T cells. Furthermore, the enhanced immune-dependent antitumor efficacy of the combination therapy with TAK-981 and trametinib was confirmed by infiltration of immune cells into tumor tissues and immunodepleting-test using immunodepleting antibodies in syngeneic immunocompetent mouse models. Together with our recent study and here, the findings support that combination inhibition of SUMOylation and MEK comprehensively conquers MYC-expressing KRAS-mutant cancers by both immune-dependent and immune-independent antitumor responses.

Abstract Background KRAS mutations frequently occur in cancers, particularly pancreatic ductal adenocarcinoma, colorectal cancer, and non-small cell lung cancer. Although KRAS G12C inhibitors have recently been approved, effective precision therapies have not yet been established for all KRAS-mutant cancers. Many treatments for KRAS-mutant cancers, including epigenome-targeted drugs, are currently under investigation. Small ubiquitin-like modifier (SUMO) proteins are a family of small proteins covalently attached to and detached from other proteins in cells via the processes called SUMOylation and de-SUMOylation. We assessed whether SUMOylation inhibition was effective in KRAS-mutant cancer cells. Methods The efficacy of the first-in-class SUMO-activating enzyme E inhibitor TAK-981 (subasumstat) was assessed in multiple human and mouse KRAS-mutated cancer cell lines. A gene expression assay using a TaqMan array was used to identify biomarkers of TAK-981 efficacy. The biological roles of SUMOylation inhibition and subsequent regulatory mechanisms were investigated using immunoblot analysis, immunofluorescence assays, and mouse models. Results We discovered that TAK-981 downregulated the expression of the currently undruggable MYC and effectively suppressed the growth of MYC-expressing KRAS-mutant cancers across different tissue types. Moreover, TAK-981-resistant cells were sensitized to SUMOylation inhibition via MYC-overexpression. TAK-981 induced proteasomal degradation of MYC by altering the balance between SUMOylation and ubiquitination and promoting the binding of MYC and Fbxw7, a key factor in the ubiquitin–proteasome system. The efficacy of TAK-981 monotherapy in immunocompetent and immunodeficient mouse models using a mouse-derived CMT167 cell line was significant but modest. Since MAPK inhibition of the KRAS downstream pathway is crucial in KRAS-mutant cancer, we expected that co-inhibition of SUMOylation and MEK might be a good option. Surprisingly, combination treatment with TAK-981 and trametinib dramatically induced apoptosis in multiple cell lines and gene-engineered mouse-derived organoids. Moreover, combination therapy resulted in long-term tumor regression in mouse models using cell lines of different tissue types. Finally, we revealed that combination therapy complementally inhibited Rad51 and BRCA1 and accumulated DNA damage. Conclusions We found that MYC downregulation occurred via SUMOylation inhibition in KRAS-mutant cancer cells. Our findings indicate that dual inhibition of SUMOylation and MEK may be a promising treatment for MYC-expressing KRAS-mutant cancers by enhancing DNA damage accumulation.

Abstract Cerebrospinal fluid tumor-derived DNA (CSF-tDNA) analysis is a promising approach for monitoring the neoplastic processes of the central nervous system. We applied a lung cancer-specific sequencing panel (CAPP-Seq) to 81 CSF, blood, and tissue samples from 24 lung cancer patients who underwent lumbar puncture (LP) for suspected leptomeningeal disease (LMD). A subset of the cohort (N = 12) participated in a prospective trial of osimertinib for refractory LMD in which serial LPs were performed before and during treatment. CSF-tDNA variant allele fractions (VAFs) were significantly higher than plasma circulating tumor DNA (ctDNA) VAFs (median CSF-tDNA, 32.7%; median plasma ctDNA, 1.8%; P

Abstract Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) is crucial for patients with lung cancer harboring EGFR mutations. However, almost all patients experience disease progression, regardless of their response to the targeted therapy, necessitating the development of additional treatment options. Two patients with lung cancer harboring EGFR‐L858R mutations in exon 21 were treated by surgical resection during successful osimertinib treatment. Because the pathological diagnosis was suspected to be pleural metastasis, osimertinib treatment was continued until disease progression. We analyzed the evolution of genomic alterations and the levels of AXL using tumor specimens obtained by repeated biopsies during the course of treatment: initial diagnosis, operation, and disease progression. Genetic alterations detected at the three time points were dramatically changed and showed reductions in numbers, while EGFR‐L858R mutations were detected in all samples tested in both patients. Immunohistochemical expression of AXL remained positive from the beginning of analysis to disease progression. Clonal evolution under oncogenesis is related to gradual accumulation of genomic alterations during tumor growth. However, our case series revealed that volume reduction procedures may cause this phenomenon. Therefore, identification of intrinsic drug‐resistant cells in tumors may be as important as detection of acquired genetic alterations.

We report a case of limited effectiveness of dabrafenib and trametinib in a 59-year-old man with poorly differentiated lung carcinoma and a rare BRAF K601E mutation. The patient, unresponsive to chemotherapy and immunotherapy, received these targeted agents as second-line treatment. Despite a notable initial response, tumor regression lasted only 52 days. A subsequent liquid biopsy revealed additional alterations (BRAF amplification, KIT amplification, TP53 S241F), indicating a complex resistance mechanism. This case underscores the challenges in treating BRAF K601E-mutant lung carcinoma, emphasizing the need for advanced molecular diagnostics, personalized approaches, and further research into more effective therapies for unique genetic profiles.

Abstract Objective This study was performed to validate the epidemiology, initial treatment, and clinical practice of lung cancer patients in the Hokushin region, Japan. Methods We retrospectively surveyed data of 5503 newly diagnosed and registered lung cancer patients in 22 principal hospital-based cancer registries in Hokushin region linked with health insurance claims data for registered patients between 2016 and 2017. Results The patients consisted of 3677 (66.8%) men and 1826 (33.2%) women with a mean (range) age of 72.2 (27–103) years). Diagnoses were small cell lung cancer (n = 512, 9.4%), squamous cell carcinoma (n = 1083, 19.7%), and non-squamous non-small cell lung cancer (NSCLC; n = 3906, 70.9%). The population with stage I disease in Toyama prefecture (41.1%) was smaller than in the other three prefectures associated with reduced selection of initial surgical therapy and increased frequencies of stage IV disease (33.2%) and best supportive care (18.6%). Initial chemotherapy for stage IV non-squamous NSCLC consisted of tyrosine kinase inhibitors in 39.3% of cases for EGFR and 4% of cases for ALK-positive non-squamous NSCLC, followed by platinum compounds (25.9%) non-platinum compounds (12.9%), and immune checkpoint inhibitors (10.2%). Carboplatin was the commonly prescribed first-line cytotoxic chemotherapeutic agent (65.4% of patients under 75 years and in 96.7% of patients over 75 years). Conclusion This study revealed real-world data on epidemiological and treatment status in lung cancer in four prefectures in Hokushin region, Japan. Simultaneous analysis of nationwide registry and insurance data could provide valuable insights for the development of lung cancer screening and medical treatment strategies. In addition, the comparative data analysis with other lesions or countries will be useful for evaluating the differences in clinical practice of cancer managements.

Abstract Objective Appropriate monitoring and management of chemotherapy-induced nausea and vomiting (CINV) with prophylactic antiemetics is important for cancer patients. This study was performed to validate the clinical practice of antiemetic use with carboplatin-based chemotherapy in lung cancer patients in the Hokushin region (Toyama, Ishikawa, Fukui, and Nagano prefectures), Japan. Methods We surveyed retrospective data of newly diagnosed and registered lung cancer patients initially treated with carboplatin-based chemotherapy in 21 principal hospitals in the Hokushin region linked with health insurance claims data between 2016 and 2017. Results A total of 1082 lung cancer patients (861 [79.6%] men, 221 [20.4%] women; median age 69.4 years [range, 33–89 years]). All patients received antiemetic therapy, with 613 (56.7%) and 469 patients (43.3%) receiving 5-hydroxytryptamine-3 receptor antagonist/dexamethasone double regimen and 5-hydroxytryptamine-3 receptor antagonist/dexamethasone/neurokinin-1 receptor antagonist triple regimen, respectively. However, the rates of double regimen and use of palonosetron were higher in Toyama and Fukui prefectures. Thirty-nine patients (3.6%) changed from double to triple regimen, while 41 patients (3.8%) changed from triple to double regimen after the second cycle, but six of these returned to triple antiemetics in subsequent cycles. Conclusion Adherence to antiemetic guidelines in clinical practice was high in Hokushin region. However, rates of double and triple antiemetic regimens differed between the four prefectures. Simultaneous analysis of nationwide registry and insurance data was valuable for evaluating and comparing the differences in the status of antiemesis and management.

Abstract Backgrounds Immune checkpoint inhibitors (ICIs) can significantly prolong the survival of patients with advanced non‐small‐cell lung cancer (NSCLC); however, few studies on the therapeutic effects of ICIs on bone metastases were performed. Methods This retrospective study aimed to investigate the therapeutic effects of ICIs and determine predictors of favorable ICI response and prognosis in 55 advanced NSCLC patients with bone metastases who initiated ICI treatment between 2016 and 2019, with a mean follow‐up period of 23.2 months. Patients were classified into responders (complete or partial response) and non‐responders (stable or progressive disease) according to the MD Anderson Cancer Center (MDA) criteria, and the predictors of therapeutic response were identified using multivariate logistic regression analysis. Furthermore, overall survival from the time of ICI administration to the final follow‐up or death was evaluated, and prognostic predictors were identified using Cox proportional hazards regression analysis. Results ICI response rate was 30.9% (complete in three cases, partial in 14). Median survival time was 9.3 months, with 1‐year and 2‐year survival rates of 40.6% and 19.3%, respectively. Responders survived significantly longer than non‐responders (p = 0.03). Based on the receiver operating characteristic curve, the predictive cutoff value of the pretreatment neutrophil‐to‐lymphocyte ratio (NLR) was 2.1. Multivariate analysis identified female sex (p = 0.03), use of ICIs as first‐line therapy (p

Abstract Background Entrectinib is an effective drug for treating solid tumors with NTRK gene rearrangement and non‐small cell lung cancer (NSCLC) with ROS1 gene rearrangement. However, its efficacy is limited by tolerance and acquired resistance, the mechanisms of which are not fully understood. The growth factors produced by the tumor microenvironment, including hepatocyte growth factor (HGF) produced by tumor‐associated fibroblasts, critically affect the sensitivity to targeted drugs. Methods We investigated whether growth factors that can be produced by the microenvironment affect sensitivity of NTRK1‐rearranged colon cancer KM12SM cells and ROS1‐rearranged NSCLC HCC78 cells to entrectinib both in vitro and in vivo. Results Among the growth factors assessed, HGF most potently induced entrectinib resistance in KM12SM and HCC78 cells by activating its receptor MET. HGF‐induced entrectinib resistance was reversed by the active‐HGF‐specific macrocyclic peptide HiP‐8 and the MET kinase inhibitor capmatinib in vitro. In addition, HGF‐producing fibroblasts promoted entrectinib resistance in vitro (culture model) and in vivo (subcutaneous tumor model). The use of capmatinib circumvented entrectinib resistance in a subcutaneous tumor model inoculated with KM12SM and HGF‐producing fibroblasts. Conclusion Our findings suggest that growth factors in the tumor microenvironment, such as HGF, may induce resistance to entrectinib in tumors with NTRK1 or ROS1 rearrangements. Our results further suggest that optimally co‐administering inhibitors of resistance‐inducing growth factors may maximize the therapeutic efficacy of entrectinib.

Abstract Background Gefitinib and erlotinib, are epidermal growth factor receptor tyrosine kinase inhibitors, and are currently recommended for non-small cell lung cancer stage IV in the elderly and in patients with decreased performance status in the Japanese Lung Cancer Society Guideline, but they occasionally caused severe hepatotoxicity requiring postponement or modification of treatment. However, little is known about the risk factors for hepatotoxicity in patients receiving gefitinib and erlotinib. In this study, we investigated the factors influencing hepatotoxicity in Japanese non-small cell lung cancer (NSCLC) patients treated with gefitinib or erlotinib monotherapy. Methods Japanese patients with NSCLC who started gefitinib or erlotinib monotherapy from January 2005 to December 2017 at Kanazawa University Hospital or Kanazawa Medical University Hospital were included in this study. Factors affecting hepatotoxicity were retrospectively investigated by multiple logistic regression analysis. Results A total of 102 patients who received gefitinib and 95 patients who received erlotinib were included in the analysis. In the gefitinib group, a body mass index (BMI) ≥ 25 was associated with an increased risk of hepatotoxicity (OR = 4.571, 95% CI = 1.486–14.056, P = 0.008). In the erlotinib group, concomitant use of acid-suppressing medications (AS), namely proton pump inhibitors or histamine-2 receptor antagonists, was associated with a reduced risk of hepatotoxicity (OR = 0.341, 95% CI = 0.129–0.900, P = 0.030). Conclusions BMI ≥ 25 in patients treated with gefitinib increased the risk of hepatotoxicity. In contrast, AS combination with erlotinib reduced the risk of hepatotoxicity. Thus, because different factors influence the risk of hepatotoxicity, monitoring for adverse events should take into account patient background factors and concomitant medications.

Abstract EGFR‐T790M mutation is a major mechanism underlying acquired resistance to first‐ and second‐generation EGFR tyrosine kinase inhibitors (EGFR‐TKIs) in lung cancer with mutated EGFR. However, differences in the biological characteristics of T790M tumors based on treatment regimens with each generation of EGFR‐TKI are not fully understood. We established cell lines with acquired resistance harboring EGFR‐T790M mutation derived from xenograft tumors treated with each generation of EGFR‐TKI and examined their biological characteristics with respect to third‐generation EGFR‐TKI osimertinib sensitivity. Second‐generation EGFR‐TKI dacomitinib‐resistant cells with T790M‐exhibited higher sensitivity to osimertinib than first‐generation EGFR‐TKI gefitinib‐resistant cells with T790M via inhibition of AKT and ERK signaling and promotion of apoptosis. Furthermore, gefitinib‐resistant cells showed enhanced intratumor heterogeneity accompanied by genomic instability and activation of alternative resistance mechanisms compared with dacomitinib‐resistant cells; this suggests that the maintenance of EGFR dependency after acquiring resistance might depend on the type of EGFR‐TKI. Our results demonstrate that the progression of tumor heterogeneity via both genetic and non‐genetic mechanisms might affect osimertinib sensitivity in tumors with acquired resistance harboring EGFR‐T790M mutation.

Abstract Patients with advanced anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer who are prescribed ALK-tyrosine kinase inhibitors (ALK-TKIs) rarely have complete responses, with residual tumors relapsing as heterogeneous resistant phenotypes. Herein, we investigated new therapeutic strategies to reduce and eliminate residual tumors in the early treatment phase. Functional genomic screening using small guide RNA libraries showed that treatment-induced adaptive survival of ALK-rearranged lung cancer cells was predominantly dependent on STAT3 activity upon ALK inhibition. STAT3 inhibition effectively suppressed the adaptive survival of ALK-rearranged lung cancer cells by enhancing ALK inhibition-induced apoptosis. The combined effects were characterized by treatment-induced STAT3 dependence and transcriptional regulation of anti-apoptotic factor BCL-XL. In xenograft study, the combination of YHO-1701 (STAT3 inhibitor) and alectinib significantly suppressed tumor regrowth after treatment cessation with near tumor remission compared with alectinib alone. Hence, this study provides new insights into combined therapeutic strategies for patients with ALK-rearranged lung cancer.

Abstract Anaplastic lymphoma kinase-tyrosine kinase inhibitors (ALK-TKIs) have shown dramatic efficacy in patients with ALK-rearranged lung cancer; however, complete response in these patients is rare. Here, we investigated the molecular mechanisms underlying the emergence and maintenance of drug-tolerant cells in ALK-rearranged lung cancer. Cell based-assays demonstrated that HER3 activation and mesenchymal-to-epithelial transition, mediated through ZEB1 proteins, help maintain cell survival and induce the emergence of ALK-TKI-tolerant cells. Compared with ALK-TKIs alone, cotreatment with pan-HER inhibitor afatinib and ALK-TKIs prevented tumor regrowth, leading to the eradication of tumors in ALK-rearranged tumors with mesenchymal features. Moreover, pre-treatment vimentin expression in clinical specimens obtained from patients with ALK-rearranged lung cancer was associated with poor ALK-TKI treatment outcomes. These results demonstrated that HER3 activation plays a pivotal role in the emergence of ALK-TKI-tolerant cells. Furthermore, the inhibition of HER3 signals combined with ALK-TKIs dramatically improves treatment outcomes for ALK-rearranged lung cancer with mesenchymal features.

Abstract A 69‐year‐old male patient presented with bloody pleural fluid effusion and elevated beta‐human chorionic gonadotropin (β‐hCG) levels obtained by thoracentesis. The patient's condition rapidly deteriorated, and he died. The autopsy revealed primary pulmonary choriocarcinoma. Early diagnosis of choriocarcinoma based on β‐hCG levels in the pleural fluid may be possible.

Abstract Background Hypogonadism associated with cancer is reported to cause cachexia and a variety of physical and psychological symptoms. This study aims to evaluate whether androgen replacement therapy can improve cancer‐related symptoms in male advanced cancer patients. Methods An investigator‐initiated, prospective, and randomized controlled study was conducted. Patients with low serum testosterone levels (total or free testosterone levels were

Through metabolome and transcriptome analyses, Nakasuka et al find that TGF-β-induced epithelial–mesenchymal transition (EMT) in non-small cell lung cancer cells is associated with reprogramming of amino acid metabolism. They also identify P4HA3 as a key enzyme involved in these changes altogether providing insights into potential mechanisms of metastasis.

Molecularly targeted cancer therapy has improved outcomes for patients with cancer with targetable oncoproteins, such as mutant EGFR in lung cancer. Yet, the long-term survival of these patients remains limited, because treatment responses are typically incomplete. One potential explanation for the lack of complete and durable responses is that oncogene-driven cancers with activating mutations of EGFR often harbor additional co-occurring genetic alterations. This hypothesis remains untested for most genetic alterations that co-occur with mutant EGFR. Here, we report the functional impact of inactivating genetic alterations of the mRNA splicing factor RNA-binding motif 10 (RBM10) that co-occur with mutant EGFR. RBM10 deficiency decreased EGFR inhibitor efficacy in patient-derived EGFR-mutant tumor models. RBM10 modulated mRNA alternative splicing of the mitochondrial apoptotic regulator Bcl-x to regulate tumor cell apoptosis during treatment. Genetic inactivation of RBM10 diminished EGFR inhibitor–mediated apoptosis by decreasing the ratio of (proapoptotic) Bcl-xS to (antiapoptotic) Bcl-xL isoforms of Bcl-x. RBM10 deficiency was a biomarker of poor response to EGFR inhibitor treatment in clinical samples. Coinhibition of Bcl-xL and mutant EGFR overcame the resistance induced by RBM10 deficiency. This study sheds light on the role of co-occurring genetic alterations and on the effect of splicing factor deficiency on the modulation of sensitivity to targeted kinase inhibitor cancer therapy.

Cancer cells develop resistance to tyrosine kinase inhibitors targeting EGFR. Here, the authors explore the mechanism of resistance to one such inhibitor - osimertinib - and find that resistance is caused by increased expression and activation of the IGF1 receptor and subsequent activation of the donwstream signalling pathway.

Abstract Background MET-deregulated non-small cell lung cancer represents an urgent clinical need because of the lack of specific therapies. Although recent studies have suggested a potential role for crizotinib in patients harboring MET gene alterations, no conclusive data are currently available. Therefore, we designed the Co-MET study, a single-arm phase II study to assess the efficacy and safety of crizotinib in patients with advanced non-small cell lung cancers harboring MET gene alterations. Methods Co-MET is an open-label, multi-center, single-arm, phase II trial to assess the safety and efficacy of oral crizotinib in patients with advanced non-small cell lung cancer harboring MET exon 14 skipping mutation (cohort 1) or a high MET gene copy number of ≥ 7 (cohort 2). We will identify MET gene alterations using RT-PCR and/or next-generation sequencing. Oral crizotinib 250 mg BID will be administered until disease progression or unacceptable toxicity. A radiology committee will review tumor scans according to the RECIST criteria. The primary endpoint is the objective response rate. Assuming a null hypothesis of 20% objective response rate and an alternative hypothesis of 50% objective response rate for cohort 1, and a one-sided alpha error of 0.05 and 80% power based on the exact binomial distribution, the required number of evaluable patients is 19. We set the exploratory sample size for cohort 2 at 10 patients. Discussion The results of this study are expected to provide evidence regarding the usefulness of oral crizotinib for advanced MET exon 14 skipping mutation-positive or MET high gene copy number-positive non-small cell lung cancer. Trial registration This study was registered with the University Hospital Medical Information Network Clinical Trials Registry as UMIN000031623 on 3 March 2018.

Abstract Background A BRAF V600E mutation is found as driver oncogene in patients with non-small cell lung cancer. Although combined treatment with dabrafenib and trametinib is highly effective, the efficacy of reduced doses of the drugs in combination therapy has not yet been reported. Case presentation A Japanese man in his mid-sixties was diagnosed with unresectable lung adenocarcinoma and was unresponsive to cytotoxic chemotherapy and immune checkpoint inhibitors. The BRAF V600E mutation was detected by next generation sequencing, and the patient was subjected to treatment with dabrafenib and trametinib in combination. Although the treatment reduced the tumor size, he experienced myalgia and muscle weakness with elevated serum creatine kinase and was diagnosed with rhabdomyolysis induced by dabrafenib and trametinib. After the patient recovered from rhabdomyolysis, the treatment doses of dabrafenib and trametinib were reduced, which prevented further rhabdomyolysis and maintained tumor shrinkage. Conclusion The reduction of the doses of dabrafenib and trametinib was effective in the treatment of BRAF V600E-mutant NSCLC, and also prevented the incidence of rhabdomyolysis.

Abstract Background The ATLANTIC trial reported that higher PD-L1 expression in tumors was involved in a higher objective response in patients with EGFR + /ALK + non-small cell lung cancer (NSCLC), indicating the possibility of anti-PD-1/PD-L1 therapy as a third-line (or later) treatment for advanced NSCLC. Therefore, the determination of status and regulatory mechanisms of PD-L1 in EGFR mutant NSCLC before and after acquired EGFR-TKIs resistance are meaningful. Methods The correlation among PD-L1, c-MET, and HGF was analyzed based on TCGA datasheets and paired NSCLC specimens before and after acquired EGFR-TKI resistance. EGFR-TKI resistant NSCLC cells with three well-known mechanisms, c-MET amplification, hepatocyte growth factor (HGF), and EGFR-T790M, were investigated to determinate PD-L1 expression status and immune escape ability. PD-L1-deleted EGFR-TKIs sensitive and resistant cells were used to evaluate the immune escape ability of tumors in mice xenograft models. Results Positive correlations were found among PD-L1, c-MET, and HGF, based on TCGA datasheets and paired NSCLC specimens. Moreover, the above three resistant mechanisms increased PD-L1 expression and attenuated activation and cytotoxicity of lymphocytes in vitro and in vivo, and downregulation of PD-L1 partially restored the cytotoxicity of lymphocytes. Both MAPK and PI3K pathways were involved in the three types of resistance mechanism-induced PD-L1 overexpression, whereas the NF-kappa B pathway was only involved in T790M-induced PD-L1 expression. Conclusions HGF, MET-amplification, and EGFR-T790M upregulate PD-L1 expression in NSCLC and promote the immune escape of tumor cells through different mechanisms.

Resistance to the new generation EGFR-TKI, Osimertinib, can emerge in patients with EGFR-mutated lung cancer. Here, the authors show that AXL, which is activated by osimertinib, can promote the emergence of tolerant lung cancer cell thus conferring resistance to osimertinib and propose the combination of Osimertinib with AXL inhibitor as a potential therapeutic approach in such resistant cancers.

Abstract Background Pulmonary carcinosarcoma (PCS) is a rare primary lung malignancy and has a poor prognosis among lung tumor histological subtypes. However, an appropriate treatment strategy has not been developed for unresectable PCS. Case presentation A 65-year-old man who was diagnosed with PCS was treated by surgical removal of the primary lung lesion, followed by six cycles of adjuvant chemotherapy with cisplatin plus irinotecan. Following the chemotherapy, he experienced a relapse with brain metastasis, which induced the rapid onset of left leg paralysis. Radical surgical resection and stereotactic radiosurgery to the resection cavity were performed. However, meningeal dissemination and new lung metastases occurred after a year and half. To control these multiple metastatic lesions, the patient was treated with the multiple kinase inhibitor pazopanib. No change was observed in the meningeal dissemination, while the metastatic lung lesions were prominently reduced in size following treatment with pazopanib. Consequently, the patient showed a partial response to pazopanib treatment, although the dose of pazopanib was reduced by half as a result of thrombocytopenia. Conclusion This is the first report of metastatic PCS showing an evident therapeutic response to tumor-targeted therapy. We suggest that pazopanib may be a therapeutic option for patients with metastatic PCS.

Summary: Brain metastasis is an ineffective process, and many cancer cells enter into an indolent state following extravasation in the brain. Single cell RNA sequencing of melanoma brain metastases reveals that non-proliferating brain metastatic melanoma cells exhibit a pattern of gene expression associated with inhibition of DNA methyltransferase 1 (DNMT1). The brain microenvironment, specifically the combination of reactive astrocytes and mechanically soft surroundings, suppressed DNMT1 expression in various cancer types and caused cell cycle delay. Somewhat unexpectedly, we find that DNMT1 suppression not only induces cell cycle delay but also activates pro-survival signals in brain metastatic cancer cells, including L1CAM and CRYAB. Our results demonstrate that transcriptional changes triggered by DNMT1 suppression is a key step for cancer cells to survive in the brain microenvironment and that they also restrict cancer cell proliferation. The dual consequences of DNMT1 suppression can explain the persistence of indolent cancer cells in the brain microenvironment.

Treatment of EGFR mutant non-small cell lung cancer (NSCLC) often develops resistance to EGFR TKIs. In this study, the authors discover a non-canonical activation of β-catenin signaling through Notch3 as a mechanism of adaptation to and resistance to EGFR TKI treatment in NSCLC.

RNAi technology has significant potential as a future therapeutic and could theoretically be used to knock down disease-specific RNAs. However, due to frequent off-target effects, low efficiency, and limited accessibility of nuclear transcripts, the clinical application of the technology remains challenging. In this study, we first assessed the stability of Cas13a mRNA and guide RNA. Next, we titrated Cas13a and guide RNA vectors to achieve effective knockdown of firefly luciferase (FLuc) RNA, used as a target transcript. The interference specificity of Cas13a on guide RNA design was next explored. Subsequently, we targeted the EML4-ALK v1 transcript in H3122 lung cancer cells. As determined by FLuc assay, Cas13a exhibited activity only toward the orientation of the crRNA–guide RNA complex residing at the 5′ of the crRNA. The activity of Cas13a was maximal for guide RNAs 24–30 bp in length, with relatively low mismatch tolerance. After knockdown of the EML4-ALK transcript, cell viability was decreased up to 50%. Cas13a could effectively knock down FLuc luminescence (70–76%), mCherry fluorescence (72%), and EML4-ALK at the protein (>80%) and transcript levels (26%). Thus, Cas13a has strong potential for use in RNA regulation and therapeutics, and could contribute to the development of personalized medicine.

Hepatocyte growth factor (HGF) is secreted as an inactive single-chain HGF (scHGF); however, only proteolytically processed two-chain HGF (tcHGF) can activate the MET receptor. We investigated the localization of tcHGF and activated/phosphorylated MET (pMET) using a tcHGF-specific antibody. In day 16.5 mouse embryos, total HGF (scHGF + tcHGF) was mainly localized in smooth muscle cells close to, but separate from, MET-positive epithelial cells in endodermal organs, including the stomach. In the adult stomach, total HGF was localized in smooth muscle cells, and tcHGF was mainly localized in the glandular base region. Immunostaining for pMET and Lgr5-driven green fluorescent protein (GFP) indicated that pMET localization overlapped with Lgr5+ gastric stem cells. HGF promoted organoid formation similar to EGF, indicating the potential for HGF to promote the survival and growth of gastric stem cells. pMET and tcHGF localizations changed during regeneration following gastric injury. These results indicate that MET is constantly activated in gastric stem cells and that the localization of pMET differs from the primary localization of precursor HGF but has a close relationship to tcHGF. Our results suggest the importance of the microenvironmental generation of tcHGF in the regulation of development, regeneration, and stem cell behavior.

We report a case of giant urachal cyst in a neonate presenting characteristic features on fetal ultrasonography. A 28-year-old woman of 21 weeks gestation was referred to our hospital for evaluation of a cystic mass in the lower portion of the fetal abdomen. On fetal ultrasonography, at 23 weeks gestation, the two umbilical arteries in the base of the umbilical cord became separated from each other due to the fetal cyst. On fetal MRI, at 25 weeks gestation, the cyst was depicted as a unilocular serous cyst, independent of the surrounding organs such as the kidney, gallbladder and intestines. The cyst had no communication with the bladder or umbilical cord. A male infant was delivered at term. Although the infant was thriving and remained asymptomatic, an enhanced CT examination 13 days after birth showed the cyst was still present without any decrease in size. The infant underwent surgery to make a definite diagnosis and to prevent future complications. The cyst was excised without any complication and finally diagnosed as a urachal cyst based on morphological and pathological findings.

M475271, 4-quinazolinamine, N-(2-chloro-5-methoxyphenyl)-6-methoxy-7-[(1-methyl-4-piperidinyl) methoxy]-(9Cl), is a new anilinoquinazoline derivative that displays selective inhibition of Src kinase activity and tumor growth in vivo. Vascular endothelial growth factor (VEGF)-induced angiogenesis plays a pivotal role in tumor growth and metastasis. Vascular endothelial (VE)-cadherin is an endothelial cell-specific adhesion molecule that can interact with the cytoskeleton via several anchoring molecules such as β-catenin. Here, we examined the effect of M475271 on VE-cadherin and β-catenin phosphorylation and association. We also examined its effect on VEGF-induced human umbilical vein endothelial cell (HUVEC) proliferation, migration, and tube formation. The findings reveal pretreatment with M475271 significantly inhibits VEGF-induced VE-cadherin and β-catenin phosphorylation. However, M475271 significantly increases VE-cadherin and β-catenin association compared to the VEGF-treated group. Confocal laser microscopic examination confirmed the augmentation effect of M475271 on VE-cadherin and β-catenin association. Finally, M475271 was shown to have inhibitory effects comparable to those of PP2 and Herbimycin A on VEGF-induced HUVEC proliferation, migration, and tube formation. These findings suggest that M475271 attenuates VEGF-induced angiogenesis by maintaining cell-cell junction stability. Although the involvement of other signaling molecules cannot be ruled out, M475271 has potential as a drug for the inhibition of the angiogenesis needed for tumor growth and metastasis. Keywords:: M475271, vascular endothelial growth factor, vascular endothelial-cadherin, β-catenin, angiogenesis

Vascular endothelial growth factor (VEGF) was reported to be a potent proangiogenic factor that plays a pivotal role in both physiological and pathological angiogenesis. M475271, 4-quinazolinamine, N-(2-chloro-5-methoxyphenyl)-6-methoxy-7-[(1-methyl-4-piperidinyl) methoxy]-(9Cl), is a new anilinoquinazoline derivative that showed selective inhibition of Src kinase activity and tumor growth in vivo. Here, we examined the effect of M475271 on VEGF-induced human umbilical vein endothelial cell (HUVEC) proliferation and migration and their intracellular mechanisms. Our findings showed that M475271 pretreatment resulted in a significant inhibition of VEGF-induced HUVEC proliferation, [3H]thymidine incorporation, and migration. M475271 inhibited VEGF-induced Flk-1 and Src phosphorylation and their association. Confocal laser microscopic examination confirmed the inhibitory effect of M475271 on VEGF-induced Flk-1/Src association. M475271 inhibited VEGF-induced extracellular signal-regulated kinase1/2 (ERK1/2) and p38 but not Akt activation in a concentration-dependent manner. M475271, PI3-K inhibitor, and p38 inhibitor inhibited VEGF-induced HUVEC proliferation and migration. However, a MEK1/2 inhibitor inhibited VEGF-induced proliferation but not migration. These findings suggest that M475271 attenuates VEGF-induced HUVEC proliferation and migration through the inhibition of signaling pathways involving Src, ERK1/2, and/or p38. Taken together, these data indicate that M475271 may be a useful candidate for inhibition of endothelial cell proliferation and migration relevant to angiogenesis. Keywords:: M475271, vascular endothelial growth factor, human umbilical vein endothelial cell proliferation and migration, angiogenesis

Resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), gefitinib and erlotinib, is a critical problem in the treatment of EGFR mutant lung cancer. Several mechanisms, including bypass signaling by hepatocyte growth factor (HGF)-triggered Met activation, are implicated as mediators of resistance. The mammalian target of rapamycin (mTOR), is a downstream conduit of EGFR and MET signaling, and is thus considered a therapeutically attractive target in the treatment of various types of cancers. The purpose of this study was to examine whether 2 clinically approved mTOR inhibitors, temsirolimus and everolimus, overcome HGF-dependent resistance to EGFR-TKIs in EGFR mutant lung cancer cells. Both temsirolimus and everolimus inhibited the phosphorylation of p70S6K and 4E-BP1, which are downstream targets of the mTOR pathway, and reduced the viability of EGFR mutant lung cancer cells, PC-9, and HCC827, even in the presence of HGF in vitro. In a xenograft model, temsirolimus suppressed the growth of PC-9 cells overexpressing the HGF-gene; this was associated with suppression of the mTOR signaling pathway and tumor angiogenesis. In contrast, erlotinib did not suppress this signaling pathway or tumor growth. Multiple mechanisms, including the inhibition of vascular endothelial growth factor production by tumor cells and suppression of endothelial cell viability, contribute to the anti-angiogenic effect of temsirolimus. These findings indicate that mTOR inhibitors may be useful for controlling HGF-triggered EGFR-TKI resistance in EGFR mutant lung cancer, and they provide the rationale for clinical trials of mTOR inhibitors in patients stratified by EGFR mutation and HGF expression status.

Although EGF receptor tyrosine kinase inhibitors (EGFR-TKI) have shown dramatic effects against EGFR mutant lung cancer, patients ultimately develop resistance by multiple mechanisms. We therefore assessed the ability of combined treatment with the Met inhibitor crizotinib and new generation EGFR-TKIs to overcome resistance to first-generation EGFR-TKIs.Lung cancer cell lines made resistant to EGFR-TKIs by the gatekeeper EGFR-T790M mutation, Met amplification, and HGF overexpression and mice with tumors induced by these cells were treated with crizotinib and a new generation EGFR-TKI.The new generation EGFR-TKI inhibited the growth of lung cancer cells containing the gatekeeper EGFR-T790M mutation, but did not inhibit the growth of cells with Met amplification or HGF overexpression. In contrast, combined therapy with crizotinib plus afatinib or WZ4002 was effective against all three types of cells, inhibiting EGFR and Met phosphorylation and their downstream molecules. Crizotinib combined with afatinib or WZ4002 potently inhibited the growth of mouse tumors induced by these lung cancer cell lines. However, the combination of high dose crizotinib and afatinib, but not WZ4002, triggered severe adverse events.Our results suggest that the dual blockade of mutant EGFR and Met by crizotinib and a new generation EGFR-TKI may be promising for overcoming resistance to reversible EGFR-TKIs but careful assessment is warranted clinically.