Cellular stress induces non-canonical activation of the receptor tyrosine kinase EphA2 through the p38-MK2-RSK signaling pathway.

The receptor tyrosine kinase ephrin type-A receptor 2 (EphA2) is overexpressed in malignant tumors. We previously reported that non-canonical EphA2 phosphorylation at Ser-897 was catalyzed by p90 ribosomal S6 kinase (RSK) via the MEK-ERK pathway in ligand- and tyrosine kinase-independent manners. Non-canonical EphA2 activation plays a key role in tumor progression; however, its activation mechanism remains unclear. In the present study, we focused on cellular stress signaling as a novel inducer of non-canonical EphA2 activation. p38, instead of ERK in the case of epidermal growth factor signaling, activated RSK-EphA2 under cellular stress conditions, including anisomycin, cisplatin, and high osmotic stress. Notably, p38 activated the RSK-EphA2 axis via downstream MAPK-activated protein kinase 2 (MK2). Furthermore, MK2 directly phosphorylated both RSK1 Ser-380 and RSK2 Ser-386, critical residues for the activation of their N-terminal kinases, which is consistent with the result showing that the C-terminal kinase domain of RSK1 was dispensable for MK2-mediated EphA2 phosphorylation. Moreover, the p38-MK2-RSK-EphA2 axis promoted glioblastoma cell migration induced by temozolomide, a chemotherapeutic agent for the treatment of glioblastoma patients. Collectively, the present results reveal a novel molecular mechanism for non-canonical EphA2 activation under stress conditions in the tumor microenvironment.

Dual inhibition of SUMOylation and MEK conquers MYC-expressing KRAS-mutant cancers by accumulating DNA damage.

BACKGROUND: KRAS mutations frequently occur in cancers, particularly pancreatic ductal adenocarcinoma, colorectal cancer, and non-small cell lung cancer. Although KRASG12C 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.

Drug-drug conjugates of MEK and Akt inhibitors for RAS-mutant cancers.

Controlling RAS mutant cancer progression remains a significant challenge in developing anticancer drugs. Whereas Ras G12C-covalent binders have received clinical approval, the emergence of further mutations, along with the activation of Ras-related proteins and signals, has led to resistance to Ras binders. To discover novel compounds to overcome this bottleneck, we focused on the concurrent and sustained blocking of two major signaling pathways downstream of Ras. To this end, we synthesized 25 drug-drug conjugates (DDCs) by combining the MEK inhibitor trametinib with Akt inhibitors using seven types of linkers with structural diversity. The DDCs were evaluated for their cell permeability/accumulation and ability to inhibit proliferation in RAS-mutant cell lines. A representative DDC was further evaluated for its effects on signaling proteins, induction of apoptosis-related proteins, and the stability of hepatic metabolic enzymes. These in vitro studies identified a series of DDCs, especially those containing a furan-based linker, with promising properties as agents for treating RAS-mutant cancers. Additionally, in vivo experiments in mice using the two selected DDCs revealed prolonged half-lives and anticancer efficacies comparable to those of trametinib. The PK profiles of trametinib and the Akt inhibitor were unified through the DDC formation. The DDCs developed in this study have potential as drug candidates for the broad inhibition of RAS-mutant cancers.

Phase 2 trial of crizotinib in Japanese patients with advanced NSCLC harboring a MET gene alteration: a Co-MET study.

BACKGROUND: MET exon 14 skipping mutations occur in 3-4% and MET high amplifications occur in < 1% of patients with non-small-cell lung cancer (NSCLC). Crizotinib, a selective ATP-competitive small-molecule inhibitor of c-Met, ALK, and ROS1 tyrosine kinases, has shown activity in cancer models with various types of MET activation. METHODS: The Co-MET study is a single-arm phase 2 trial to assess the safety and efficacy of crizotinib in MET inhibitor-naïve patients with advanced NSCLC harboring MET exon 14 skipping mutation (cohort 1) or high MET gene copy number of ≥ 7 (cohort 2). The primary endpoint was the objective response rate (ORR) per RECIST v1.1 by independent radiology review in cohort 1. The key secondary endpoints were the duration of response (DoR), progression-free survival (PFS), overall survival (OS), and safety. RESULTS: A total of 28 patients (23 in cohort 1 and 5 in cohort 2) were enrolled between March 2018 and February 2020. The primary endpoint was met as the ORR (90% confidence interval: CI) in cohort 1 was 38.1% (20.6-58.3). Median DoR, PFS, and OS (95% CI) were 7.6 (1.9-NE), 5.7 (2.1-11.3), 9.1 (4.0-19.9) months, respectively, in cohort 1. ORR in cohort 2 was 40.0% (18.9-92.4). The safety signals were generally consistent with the known safety profile of crizotinib. CONCLUSIONS: Crizotinib showed a clinical activity similar to that of tepotinib and capmatinib in patients with NSCLC harboring MET exon 14 skipping mutations. CLINICAL TRIAL INFORMATION: UMIN000031623.

Pan-HER inhibitors overcome lorlatinib resistance caused by NRG1/HER3 activation in ALK-rearranged lung cancer.

Lorlatinib, a third-generation anaplastic lymphoma kinase (ALK)-tyrosine kinase inhibitor (TKI) with a broad coverage against ALK mutations, has demonstrated dramatic effects in patients with ALK-rearranged lung cancer. The mechanisms of acquired resistance to lorlatinib by secondary ALK compound mutations have recently been reported; however, resistance mechanisms other than secondary mutations remain unclear. Here, we investigated the molecular mechanisms of the acquired resistance in ALK-rearranged lung cancer cells in vitro. We established two different lorlatinib-resistant ALK-rearranged lung cancer cell lines (H3122LR and A925LLR) via long-term administration of lorlatinib. These resistant cells did not harbor the secondary ALK mutations and showed cross-resistance to the other kinds of ALK-TKIs (crizotinib or alectinib) compared with the parental cells; however, these resistant cells overexpressed the phosphorylated human epidermal growth factor receptor 3 (HER3) protein and the ligand of HER3 (neuregulin 1; NRG1). Pharmacological inhibition of HER3 with pan-HER inhibitors or genetic knockdown of HER3 with siRNA resensitized H3122LR and A925LLR cells to lorlatinib in vitro, indicating that H3122LR and A925LLR acquired resistance by NRG1/HER3 activation. These findings demonstrated that targeting NRG1/HER3 is a potential novel therapeutic option for lorlatinib-resistant ALK-rearranged lung cancer.

High levels of AXL expression in untreated EGFR-mutated non-small cell lung cancer negatively impacts the use of osimertinib.

For non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations, the initial therapeutic interventions will have crucial impacts on their clinical outcomes. Drug tolerant factors reportedly have an impact on EGFR-tyrosine kinase inhibitor sensitivity. This prospective study investigated the impacts of drug tolerant-related protein expression in tumors based on the efficacy of osimertinib in the first-setting of EGFR-mutated advanced NSCLC patients. A total of 92 patients with EGFR-mutated advanced or postoperative recurrent NSCLC were analyzed and treated with osimertinib at 14 institutions in Japan. AXL, p53, and programmed death-ligand 1 (PD-L1) expression in patient tumors was determined using immunohistochemistry. The AXL signaling pathway was investigated using a cell line-based assay and AXL-related gene expression in The Cancer Genome Atlas (TCGA) database. High levels of AXL and positive-p53 expression were detected in 26.1% and 53.3% of the pretreatment EGFR-mutated NSCLC tumors, respectively. High AXL expression levels were significantly associated with a shorter progression-free survival compared with low AXL expression levels, irrespective of the EGFR activating mutation status (p = 0.026). Cell line-based assays indicated that the overexpression of AXL protein accelerated PD-L1 expression, which induced insensitivity to osimertinib. In the TCGA database, AXL RNA levels were positively correlated with PD-L1 expression in the lung adenocarcinoma cohort. The results show that high AXL expression levels in tumors impact clinical predictions when using osimertinib to treat EGFR-mutated NSCLC patients. Trial Registration: UMIN000043942.

Multi-institutional survey of antiemetic therapy in lung cancer patients treated with carboplatin in Hokushin region.

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.

Epidemiological and therapeutic profiles of lung cancer patients in the Hokushin Region Japan: a retrospective hospital administrative database study.

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.

Inhibition of EGFR and MEK surmounts entrectinib resistance in a brain metastasis model of NTRK1-rearranged tumor cells.

Tropomyosin receptor kinase (TRK) inhibitors have demonstrated histology-agnostic efficacy in patients with neurotrophic receptor tyrosine kinase (NTRK) gene fusion. Although responses to TRK inhibitors can be dramatic and durable, duration of response may eventually be limited by acquired resistance via several mechanisms, including resistance mutations such as NTRK1-G595R. Repotrectinib is a second-generation TRK inhibitor, which is active against NTRK1-G595R. However, its efficacy against entrectinib-resistant tumors has not been fully elucidated. In the present study, we established entrectinib-resistant tumor cells (M3B) in a brain metastasis model inoculated with NTRK1-rearranged KM12SM cells and examined the sensitivity of M3B cells to repotrectinib. While M3B cells harbored the NTRK1-G595R mutation, they were unexpectedly resistant to repotrectinib. The resistance was due to extracellular signal-regulated kinase (ERK) reactivation partially mediated by epidermal growth factor receptor (EGFR) activation. We further demonstrate that the triplet combination of repotrectinib, EGFR inhibitor, and MEK inhibitor could sensitize M3B cells in vitro as well as in a brain metastasis model. These results indicate that resistant mutations, such as NTRK1-G595R, and alternative pathway activation, such as ERK activation, could simultaneously occur in entrectinib-resistant tumors, thereby causing resistance to second-generation inhibitor repotrectinib. These findings highlight the importance of intensive examinations to identify resistance mechanisms and application of the appropriate combination treatment to circumvent the resistance.

Dual blockade of MET and VEGFR2 signaling pathways as a potential therapeutic maneuver for peritoneal carcinomatosis in scirrhous gastric cancer.

Scirrhous gastric cancer frequently develops into peritoneal carcinomatosis with malignant ascites, leading to an extremely poor prognosis. We had demonstrated that paracrine hepatocyte growth factor (HGF)-induced MET activation promotes peritoneal carcinomatosis with ascites formation. The vascular endothelial growth factor (VEGF) receptor (VEGFR)/VEGF axis facilitates tumor progression and formation of malignant ascites. This study investigated the role of MET and VEGFR2 in the development of peritoneal carcinomatosis with malignant ascites. Cabozantinib is a dual inhibitor of MET and VEGFR2. We examined the effects of cabozantinib on MET- and VEGFR2-mediated progression of peritoneal carcinomatosis in human scirrhous gastric cancer in vitro and in vivo. Cabozantinib inhibited HGF-stimulated proliferation of scirrhous cancer cell lines NUGC4 and GCIY, with a high potential to generate peritoneal carcinomatosis with ascites fluid, as well as the constitutive proliferation of MKN45 cells with MET amplification. Cabozantinib also inhibited the phosphorylation of both MET and VEGFR2 in scirrhous cancer cells and HGF- or VEGF-stimulated HUVECs. It effectively reduced ascitic fluid and prolonged the survival of NUGC4-inoculated nude mice. In clinical specimens, malignant ascites fluid from patients with peritoneal carcinomatosis contained high levels of HGF and VEGF. Our results strongly suggest that MET- and VEGFR2-mediated signaling pathways play pivotal roles in the pathogenesis of peritoneal carcinomatosis in scirrhous gastric cancer. Thus, the dual blockade of MET and VEGFR2 signaling may be a potential therapeutic maneuver for peritoneal carcinomatosis in scirrhous gastric cancer.

Treatment of Retinoblastoma 1-Intact Hepatocellular Carcinoma With Cyclin-Dependent Kinase 4/6 Inhibitor Combination Therapy.

BACKGROUND AND AIMS: Synthetic cyclin-dependent kinase (CDK) 4/6 inhibitors exert antitumor effects by forcing RB1 in unphosphorylated status, causing not only cell cycle arrest but also cellular senescence, apoptosis, and increased immunogenicity. These agents currently have an indication in advanced breast cancers and are in clinical trials for many other solid tumors. HCC is one of promising targets of CDK4/6 inhibitors. RB family dysfunction is often associated with the initiation of HCC; however, this is revivable, as RB family members are not frequently mutated or deleted in this malignancy. APPROACH AND RESULTS: Loss of all Rb family members in transformation related protein 53 (Trp53)-/- mouse liver resulted in liver tumor reminiscent of human HCC, and re-expression of RB1 sensitized these tumors to a CDK4/6 inhibitor, palbociclib. Introduction of an unphosphorylatable form of RB1 (RB7LP) into multiple liver tumor cell lines induced effects similar to palbociclib. By screening for compounds that enhance the efficacy of RB7LP, we identified an I kappa B kinase (IKK)ß inhibitor Bay 11-7082. Consistently, RB7LP expression and treatment with palbociclib enhanced IKKα/ß phosphorylation and NF-κB activation. Combination therapy using palbociclib with Bay 11-7082 was significantly more effective in hepatoblastoma and HCC treatment than single administration. Moreover, blockade of IKK-NF-κB or AKT pathway enhanced effects of palbociclib on RB1-intact KRAS Kirsten rat sarcoma viral oncogene homolog mutated lung and colon cancers. CONCLUSIONS: In conclusion, CDK4/6 inhibitors have a potential to treat a wide variety of RB1-intact cancers including HCC when combined with an appropriate kinase inhibitor.

Cancer among children, adolescents and young adults in the Hokushin region, Japan, between 2010 and 2015.

Adolescents and young adults with cancer encounter age-related challenges. Cancer treatment and support are not always tailored to the needs of each patient due to difficulty in the collection of accurate data. The present study aimed to investigate cancer among children and adolescents and young adults in the four adjacent prefectures of Japan (Toyama, Ishikawa, Fukui and Nagano) by analyzing data from a unique regional cancer database. We retrieved and analyzed the data of pediatric and adolescent and young adult patients aged between 0 and 39 years at cancer diagnosis (including carcinoma in situ), which was registered in the Hokushin Ganpro database between 2010 and 2015. A total of 5718 cases (1571 males and 4147 females) were identified during this period. The overall male-to-female ratio was 1:2.6. There was no distinct difference in the number of cancer cases per 100 000 population between males and females until 19 years of age. The difference became more pronounced after 20 years of age. The number of cancer cases (per 100 000 population) in the 0-14-, 15-19-, 20-29- and 30-39-year age groups was estimated to be 13.4, 14.5, 44.0 and 101.5, respectively. Carcinomas were the most common type of cancer in the adolescents and young adults (15-39 years) population (74%), whereas they were not the predominant cancer type in the pediatric (0-14 years) population. Although further research is needed to understand the needs of adolescents and young adults with cancer, we believe that our findings will help guide efforts to improve the management strategy for adolescents and young adults with cancer.

[Cancer Professional Training Program in Hokushin Region].

The Hokushin-Gan-pro, consists of Kanazawa University, Shinshu University, Toyama University, Fukui University, Kanazawa Medical University, Ishikawa Prefectural Nursing University, located in Nagano, Toyama, Ishikawa and Fukui prefectures( Hokushin region), conducts educational program to train professionals for management of cancer patients. We have launched 10 graduate student courses and 11 medical staff courses, and are accepting students who exceed our expectation. We give lectures using e-learning system and hold multidisciplinary seminars that utilize the Web conference system. As an overseas staff training, participants learned cancer genomic medicine and cancer palliative care at medical facilities in 3 countries. The regional cancer database project that utilizes cancer registration data from 22 principal hospitals to clarify the characteristics of cancer patients with disabilities, pleural mesothelioma, pleural adenocarcinoma, and pediatric/ adolescents and young adults(AYA)generation cancer patients in Hokushin region. In addition, public lectures were held to provide cancer information to the citizens in Hokushin region.

Trametinib overcomes KRAS-G12V-induced osimertinib resistance in a leptomeningeal carcinomatosis model of EGFR-mutant lung cancer.

Leptomeningeal carcinomatosis (LMC) occurs frequently in non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations and is associated with acquired resistance to EGFR tyrosine kinase inhibitors (EGFR-TKIs). However, the mechanism by which LMC acquires resistance to osimertinib, a third-generation EGFR-TKI, is unclear. In this study, we elucidated the resistance mechanism and searched for a novel therapeutic strategy. We induced osimertinib resistance in a mouse model of LMC using an EGFR-mutant NSCLC cell line (PC9) via continuous oral osimertinib treatment and administration of established resistant cells and examined the resistance mechanism using next-generation sequencing. We detected the Kirsten rat sarcoma (KRAS)-G12V mutation in resistant cells, which retained the EGFR exon 19 deletion. Experiments involving KRAS knockdown in resistant cells and KRAS-G12V overexpression in parental cells revealed the involvement of KRAS-G12V in osimertinib resistance. Cotreatment with trametinib (a MEK inhibitor) and osimertinib resensitized the cells to osimertinib. Furthermore, in the mouse model of LMC with resistant cells, combined osimertinib and trametinib treatment successfully controlled LMC progression. These findings suggest a potential novel therapy against KRAS-G12V-harboring osimertinib-resistant LMC in EGFR-mutant NSCLC.

Enhanced anti-tumor efficacy of IL-7/CCL19-producing human CAR-T cells in orthotopic and patient-derived xenograft tumor models.

Chimeric antigen receptor (CAR)-T cell therapy has impressive efficacy in hematological malignancies, but its application in solid tumors remains a challenge. Multiple hurdles associated with the biological and immunological features of solid tumors currently limit the application of CAR-T cells in the treatment of solid tumors. Using syngeneic mouse models, we recently reported that CAR-T cells engineered to concomitantly produce interleukin (IL)-7 and chemokine (C-C motif) ligand 19 (CCL19)-induced potent anti-tumor efficacy against solid tumors through an improved ability of migration and proliferation even in an immunosuppressive tumor microenvironment. In this study, for a preclinical evaluation preceding clinical application, we further explored the potential of IL-7/CCL19-producing human CAR-T cells using models that mimic the clinical features of solid tumors. Human anti-mesothelin CAR-T cells producing human IL-7/CCL19 achieved complete eradication of orthotopic pre-established malignant mesothelioma and prevented a relapse of tumors with downregulated antigen expression. Moreover, mice with patient-derived xenograft of mesothelin-positive pancreatic cancers exhibited significant inhibition of tumor growth and prolonged survival following treatment with IL-7/CCL19-producing CAR-T cells, compared to treatment with conventional CAR-T cells. Transfer of IL-7/CCL19-producing CAR-T cells resulted in an increase in not only CAR-T cells but also non-CAR-T cells within the tumor tissues and downregulated the expression of exhaustion markers, including PD-1 and TIGIT, on the T cells. Taken together, our current study elucidated the exceptional anti-tumor efficacy of IL-7/CCL19-producing human CAR-T cells and their potential for clinical application in the treatment of patients with solid tumors.

Macrocyclic peptide-based inhibition and imaging of hepatocyte growth factor.

Activation of hepatocyte growth factor (HGF) by proteolytic processing is triggered in cancer microenvironments, and subsequent signaling through the MET receptor is involved in cancer progression. However, the structure of HGF remains elusive, and few small/medium-sized molecules can modulate HGF. Here, we identified HiP-8, a macrocyclic peptide consisting of 12 amino acids, which selectively recognizes active HGF. Biochemical analysis and real-time single-molecule imaging by high-speed atomic force microscopy demonstrated that HiP-8 restricted the dynamic domains of HGF into static closed conformations, resulting in allosteric inhibition. Positron emission tomography using HiP-8 as a radiotracer enabled noninvasive visualization and simultaneous inhibition of HGF-MET activation status in tumors in a mouse model. Our results illustrate the conformational change in proteolytic activation of HGF and its detection and inhibition by a macrocyclic peptide, which may be useful for diagnosis and treatment of cancers.

Multi-institutional survey of cancer disparities in disabled patients in the region of northwestern Japan.

BACKGROUND: Potential disparities between cancer patients with and without disabilities remained to be validate in Japan. METHODS: We surveyed retrospective data on hospital cancer registration as well as information on disability certificates obtained through the Hokushin Ganpro database. In total, 93,545 cancer patients in 10 principal hospitals covering the region of northwestern Japan were registered with the Hokushin Ganpro database between 2010 and 2015. The database included the following data: diagnosis date, cancer type, staging, treatment, cancer detection process, and possession of a disability certificate. RESULTS: We found that 2983 patients, which accounted for 3.2% of the total patients, had disabilities. No significant differences in gender, age at diagnosis, cancer stage distribution, and cancer incidence rates were observed between the disabled and non-disabled patients. Even though the proportion of early-stage cancer among disabled patients differed only slightly from that in non-disabled patients, early-stage cancer was more frequently diagnosed in patients with disabilities during their regular hospital visits than in those without disabilities, who had more opportunity for early cancer detection during cancer screening. According to in-house data reflecting treatment period and process from a single hospital, all 16 disabled patients treated with chemotherapy completed the treatment until disease progression or end of predetermined cycles. CONCLUSION: These results indicate that deep disparities between cancer patients with and without disabilities are not apparent and that the disabled patients in the region of northwestern Japan receive appropriate hospital follow-up.

High-Speed AFM Reveals Molecular Dynamics of Human Influenza A Hemagglutinin and Its Interaction with Exosomes.

Influenza A hemagglutinin (HA) is one of the crucial virulence factors that mediate host tropism and viral infectivity. Presently, the mechanism of the fusogenic transition of HA remains elusive. Here, we used high-speed atomic force microscopy (HS-AFM) to decipher the molecular dynamics of HA and its interaction with exosomes. Our data reveal that the native conformation of HA in the neutral buffer is ellipsoidal, and HA undergoes a conformational change in an acidic buffer. Real-time visualization of the fusogenic transition by HS-AFM suggests that the mechanism is possibly fit to the "uncaging" model, and HA intermediate appears as Y-shaped. A firm interaction between the HA and exosome in an acidic buffer indicates the insertion of a fusion peptide into the exosomal layer and subsequently destabilizes the layer, resulting in the deformation or rupture of exosomes, releasing exosomal contents. In contrast, the HA-exosome interaction is weak in a neutral buffer because the interaction is mediated by weak bonds between the HA receptor-binding site and receptors on the exosome.

Glycogen synthase kinase-3 inhibition overcomes epithelial-mesenchymal transition-associated resistance to osimertinib in EGFR-mutant lung cancer.

A novel epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor, osimertinib, has marked efficacy in patients with EGFR-mutant lung cancer. While epithelial-mesenchymal transition (EMT) plays a role in the resistance to various targeted drugs, its involvement in EGFR-inhibitor resistance remains largely unknown. Preclinical experiments with osimertinib-resistant lung cancer cells showed that EMT was associated with decreased microRNA-200c and increased ZEB1 expression. In several resistant clone cells, pretreatment with the histone deacetylase inhibitor quisinostat helped overcome the resistance by reverting EMT. Furthermore, drug screening from a library of 100 kinase inhibitors indicated that Glycogen synthase kinase-3 (GSK-3) inhibitors, such as LY2090314, markedly inhibited the growth and induced apoptosis of resistant cells, specifically those with a mesenchymal phenotype. These results suggest that GSK-3 inhibition could be useful to circumvent EMT-associated resistance to osimertinib in EGFR-mutant lung cancer.

MET amplification results in heterogeneous responses to osimertinib in EGFR-mutant lung cancer treated with erlotinib.

The third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) osimertinib is approved for untreated, or previously EGFR-TKI-treated T790M-positive EGFR-mutated non-small cell lung carcinoma (NSCLC). We investigated the heterogeneity of responses to osimertinib and its underlying mechanisms. A patient with EGFR-L858R-mutated NSCLC was treated with erlotinib. Following treatment, he developed brain and multiple bone metastases and was eventually diagnosed with NSCLC with EGFR-T790M mutation. The responses of various tumor specimens to osimertinib were heterogeneous. We investigated EGFR-T790M and MET amplification using PCR and FISH in autopsy specimens of the cervical spine, lumbar spine, and brain. We established the KNZ osimertinib-resistant (KNZ_OR) tumor cell line with MET amplification using a cervical spine lesion that was intrinsically resistant to osimertinib. We evaluated the effects of MET knockdown and MET inhibitor on KNZ_OR cell sensitivity to osimertinib in vitro and in vivo. Osimertinib-resistant lesions (cervical spine and brain) showed EGFR-L858R and MET amplification, but not EGFR-T790M, whereas osimertinib-sensitive lesions (lumbar spine) showed EGFR-L858R and -T790, but not MET amplification. Osimertinib decreased the association of amplified MET with L858R-mutated EGFR but increased that with human epidermal growth factor receptor 3 in KNZ_OR cells. MET knockdown or MET inhibitor sensitized KNZ_OR cells to osimertinib in vitro, indicating that MET amplification induced osimertinib resistance. Combination with osimertinib plus crizotinib induced tumor shrinkage in the KNZ_OR xenograft model. Hence, MET amplification might induce heterogeneous responses to osimertinib in EGFR-mutated NSCLC. Further investigations on mutated EGFR and amplified MET might lead to the development of effective therapies.