c-Met Levels Research Articles

Abstract 810: Anti-tumor effects of Sym015 in HGF overexpressing gastric cancer cell lines

Abstract MET, hepatocyte growth factor receptor (HGFR), has received considerable attention as a potential target for cancer therapy. MET and its ligand, HGF are associated with poor outcomes and significantly shorter overall survival in various cancer types including gastric cancer (GC). Although MET inhibitors have been shown to be sensitive to tumors with MET amplification, it is relatively rare that incidence is 4-5 % in GC and no MET inhibitor has succeeded in clinical trials so far. Therefore, development of better MET inhibitors and new biomarkers to identify proper patients to benefit from MET inhibitors is needed. We previously analyzed the sensitivity of a novel MET inhibitor, Sym015, a mixture of two human monoclonal antibodies directed at MET, according to MET/HGF status in 49 GC cell lines. Interestingly, two HGF overexpressing cell lines, IM95m and SNU484 were sensitive to 100 nM Sym015 with inhibition rate 52.3 and 23.4 %, respectively. HGF expression in lysate was 7,970 and 2,908 pg/ml and both cell lines had low levels of c-MET and p-MET. To evaluate the influence of HGF overexpression on the antitumor effect of Sym015, sensitivity was measured by CCK-8 assay and cell proliferation was determined by counting cells. Invasiveness was assessed through Transwell assay. Cell viability, invasiveness and related downstream molecules were assessed after HGF silencing by siRNA. In vivo, both cell lines were injected into BALB/c nude mice and Sym015 was applied (50mg/kg, 3qw) and tumor volume and weight were measured every other day. As a result, median inhibition rate of Sym015 in the two HGF overexpressing cell lines was 37.9 %, which was similar to the 44.9 % seen with MET amplified cell lines. The cell proliferation was delayed about 1.6 times and 1.2 times and also invasiveness was decreased by 12.9 and 29.5 % in IM95m and SNU484, respectively. After HGF silencing, inhibition rate at 100 nM Sym015 was significantly decreased (p=0.007) from 50.9 to 15.1 % due to AKT pathway activation in IM95m. There was no change in inhibition rate (from 12.2 to 14.8 %) and downstream pathway molecules in SNU484. Also, after silencing HGF expression, the inhibition effect of Sym015 on invasiveness was reduced from 29.8 % to no inhibition in SNU484 and there was no HGF silencing effect of Sym015 in invasiveness in IM95m. In vivo, xenograft models of IM95m and SNU484 both showed a significant reduction of 53.4 and 30.7 % in tumor volume at time of sacrifice, respectively (p<0.0001). Especially Sym015 effectively inhibited the growth of tumor in IM95m than SNU484. Downstream molecular changes are under evaluation. Consequently, Sym015 was effective in HGF overexpressing cell lines and HGF overexpression induced Sym015 sensitivity was shown in IM95m and the inhibitory effect of invasiveness was shown in SNU484. We suggest that HGF overexpression influences the sensitivity of MET inhibitor and could be a potential predictive marker in GC. Citation Format: Hyun Jeong Kim, Sun Kyoung Kang, Michael Kragh, Ivan D. Horak, Woo Sun Kwon, Tae Soo Kim, Inhye Jeong, Joong Bae Ahn, Hyun Cheol Chung, Sun Young Rha. Anti-tumor effects of Sym015 in HGF overexpressing gastric cancer cell lines [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 810.

Therapeutic Effect of HGF on NASH Mice Through HGF/c-Met and JAK2-STAT3 Signalling Pathway

Introduction and aim. Hepatocyte growth factor (HGF) has been shown to ameliorate liver inflammation and fibrosis; however, the mechanism underlying its effects in non-alcoholic steatohepatitis (NASH) is unclear. This study aimed to analyse the relationship between the JAK2-STAT3 signalling pathway and the ameliorating effect of HGF on NASH.Material and methods. Mice were fed a high-fat diet (HFD) for 16 weeks, and then plasma and hepatic tissues were collected. Histological and clinical chemistry assays were performed to assess liver disease. The mRNA and protein levels of JAK2, STAT3, and c-Met were assessed by realtime PCR and western blotting, respectively.Results. Serum ALT, AST, and TG levels were increased in NASH mice. Histological analysis showed different degrees of steatosis, inflammatory infiltrates, and fibrosis in HFD animals. Exogenous administration of recombinant human (rh) HGF via the tail vein for 14 days markedly decreased ALT and AST to levels lower than those in the control group. Compared with the levels in HFD mice, c-Met, p-c-Met, JAK2, p-JAK2, and p-STAT3 levels were increased in mice that were administered HGF (P < 0.05). Furthermore, silencing of HGF or blocking of its receptor c-Met affected JAK2 and STAT3 protein phosphorylation.Conclusions. Excess HGF highly probable improved NASH liver function. Combined with its ligand, c-Met, HGF may promote the phosphorylation of JAK2-STAT3 and inhibit inflammation in NASH. Therefore, it may be potentially useful treatment for NASH.

Identification of Differential Transcriptional Patterns in Primary and Secondary Hyperparathyroidism.

Hyperparathyroidism is associated with hypercalcemia and the excess of parathyroid hormone secretion; however, the alterations in molecular pattern of functional genes during parathyroid tumorigenesis have not been unraveled. We aimed at establishing transcriptional patterns of normal and pathological parathyroid glands (PGs) in sporadic primary (HPT1) and secondary hyperparathyroidism (HPT2). To evaluate dynamic alterations in molecular patterns as a function of the type of PG pathology, a comparative transcript analysis was conducted in subgroups of healthy samples, sporadic HPT1 adenoma and hyperplasia, and HPT2. Normal, adenomatous, HPT1, and HPT2 hyperplastic PG formalin-fixed paraffin-embedded samples were subjected to NanoString analysis. In silico microRNA (miRNA) analyses and messenger RNA-miRNA network in PG pathologies were conducted. Individual messenger RNA and miRNA levels were assessed in snap-frozen PG samples. The expression levels of c-MET, MYC, TIMP1, and clock genes NFIL3 and PER1 were significantly altered in HPT1 adenoma compared with normal PG tissue when assessed by NanoString and quantitative reverse transcription polymerase chain reaction. RET was affected in HPT1 hyperplasia, whereas CaSR and VDR transcripts were downregulated in HPT2 hyperplastic PG tissue. CDH1, c-MET, MYC, and CaSR were altered in adenoma compared with hyperplasia. Correlation analyses suggest that c-MET, MYC, and NFIL3 exhibit collective expression level changes associated with HPT1 adenoma development. miRNAs, predicted in silico to target these genes, did not exhibit a clear tendency upon experimental validation. The presented gene expression analysis provides a differential molecular characterization of PG adenoma and hyperplasia pathologies, advancing our understanding of their etiology.

The irreversible ERBB1/2/4 inhibitor neratinib interacts with the PARP1 inhibitor niraparib to kill ovarian cancer cells

ABSTRACTThe irreversible ERBB1/2/4 inhibitor neratinib has been shown to rapidly down-regulate the expression of ERBB1/2/4 as well as the levels of c-MET, PDGFRα and mutant RAS proteins via autophagic degradation. Neratinib interacted in an additive to synergistic fashion with the approved PARP1 inhibitor niraparib to kill ovarian cancer cells. Neratinib and niraparib caused the ATM-dependent activation of AMPK which in turn was required to cause mTOR inactivation, ULK-1 activation and ATG13 phosphorylation. The drug combination initially increased autophagosome levels followed later by autolysosome levels. Preventing autophagosome formation by expressing activated mTOR or knocking down of Beclin1, or knock down of the autolysosome protein cathepsin B, reduced drug combination lethality. The drug combination caused an endoplasmic reticulum stress response as judged by enhanced eIF2α phosphorylation that was responsible for reducing MCL-1 and BCL-XL levels and increasing ATG5 and Beclin1 expression. Knock down of BIM, but not of BAX or BAK, reduced cell killing. Expression of activated MEK1 prevented the drug combination increasing BIM expression and reduced cell killing. Downstream of the mitochondrion, drug lethality was partially reduced by knock down of AIF, but expression of dominant negative caspase 9 was not protective. Our data demonstrate that neratinib and niraparib interact to kill ovarian cancer cells through convergent DNA damage and endoplasmic reticulum stress signaling. Cell killing required the induction of autophagy and was cathepsin B and AIF -dependent, and effector caspase independent.

Biomarker expression in rectal cancer tissue before and after neoadjuvant therapy.

PurposeIntraoperative identification of rectal cancer (RC) can be challenging, especially because of fibrosis after treatment with preoperative chemo- and radiotherapy (CRT). Tumor-targeted fluorescence imaging can enhance the contrast between tumor and normal tissue during surgery. Promising targets for RC imaging are carcinoembryonic antigen (CEA), epithelial cell adhesion molecule (EpCAM) and the tyrosine-kinase receptor Met (c-Met). The effect of CRT on their expression determines their applicability for imaging. Therefore, we investigated whether CRT modifies expression patterns in tumors, lymph node (LN) metastases and adjacent normal rectal tissues.Patients and methodsPreoperative biopsies, primary tumor specimens and metastatic LNs were collected from 38 RC patients who did not receive CRT (cohort 1) and 34 patients who did (cohort 2). CEA, EpCAM and c-Met expression was determined using immunohistochemical staining and was semiquantified by a total immunostaining score (TIS), consisting of the percentage and intensity of stained tumor cells (0–12).ResultsIn both cohorts CEA, EpCAM and c-Met were significantly highly expressed in >60% of tumor tissues compared with adjacent normal epithelium (T/N ratio, P<0.01). EpCAM showed the most homogenous expression in tumors, whereas CEA showed the highest T/N ratio. Most importantly, CEA and EpCAM expression did not significantly change in normal or neoplastic RC tissue after CRT, whereas levels of c-Met changed (P=0.02). Tissues of eight patients with a pathological complete response after CRT showed expression of all biomarkers with TIS close to normal epithelium.ConclusionHistological evaluation shows that CEA, EpCAM and c-Met are suitable targets for RC imaging, because all three are significantly enhanced in cancer tissue from primary tumors or LN metastases compared with normal adjacent tissue. Furthermore, the expression of CEA and EpCAM is not significantly changed after CRT. These data underscore the applicability of c-Met and especially, CEA and EpCAM as targets for image-guided RC surgery, both before and after CRT.

FoxM1 promotes epithelial-mesenchymal transition, invasion, and migration of tongue squamous cell carcinoma cells through a c-Met/AKT-dependent positive feedback loop.

Forkhead box protein M1 (FoxM1) has been associated with cancer progression and metastasis. However, the function of FoxM1 in tongue squamous cell carcinoma (TSCC) remains largely unknown. The purpose of this study was to determine the role of FoxM1 in regulation of epithelial-mesenchymal transition (EMT) and migration of TSCC cells. We found that FoxM1 induced EMT and increased invasion/migration capacity in SCC9 and SCC25 cells. FoxM1 stimulation increased c-Met, pAKT, and vimentin levels but decreased E-cadherin level. Chromatin immunoprecipitation assay established that FoxM1 is bound to the promoter of c-Met to activate its transcription. In turn, c-Met promoted the expression of FoxM1 and pAKT. Blocking AKT signaling attenuated the invasion and migration of SCC9 and SCC25 cells stimulated by FoxM1 or c-Met. These results indicate that a positive feedback loop controls the EMT and migration of TSCC cells induced by FoxM1 and c-Met through AKT. Furthermore, the expression levels of FoxM1, pAKT, and c-Met were found to significantly increase in TSCC tissues compared with normal tissues, and these three biomarkers were concomitantly expressed in TSCC tissues. Clinical association analyses indicated that the expression of FoxM1, c-Met, and pAKT was associated with clinicopathological characteristics of patients with TSCC including tumor stage, tumor size, and lymph node metastasis. Taken together, our findings suggest that FoxM1 promotes the EMT, invasion and migration of TSCC cells, and cross-talks with c-Met/AKT signaling to form a positive feedback loop to promote TSCC development.

Expression of the hepatocyte growth factor and c-Met in colon cancer: correlation with clinicopathological features and overall survival.

The hepatocyte growth factor (HGF)/c-Met signaling system has been implicated in the development and progression of colon cancer, but the relationship between the expression of HGF or c-MET and clinicopathologic features remains controversial. In the study, we analyzed the expression of HGF and c-Met in colon cancer and assessed the influence of the expression of this growth factor and its receptor on clinical and histological parameters and patient survival. We investigated the mRNA expression of HGF and c-Met with real-time PCR in 90 unselected colon carcinomas and the corresponding normal mucosa. Furthermore, HGF and c-Met protein expression was investigated with immunohistochemistry in all the samples. The mRNA and protein expression levels of HGF and c-Met were significantly higher in colon cancer than in matched normal mucosa. The protein level in most of the cases investigated was correlated with the mRNA level. Overexpression of HGF and c-Met, at both protein and mRNA levels, was correlated with depth of invasion, lymph node metastases and overall AJCC stage. According to univariate analysis, the mean survival time was shorter in the HGF-positive and c-Met-positive groups. Multivariate Cox analysis showed that high M stage and the expression of c-Met independently had a negative impact on overall survival. The HGF/c-Met signaling pathway may be involved in the pathogenesis and progression of colon cancer. C-Met overexpression can be used as a useful parameter to evaluate the prognosis of colon cancer.

C-Met-Activated Mesenchymal Stem Cells Rescue Ischemic Damage via Interaction with Cellular Prion Protein

Background/Aims: Stem cell transplantation has emerged as a promising therapeutic strategy, but the exact mechanisms by which stem cells exposed to hypoxic conditions increase the survival rate and rescue ischemic injury at the graft site are not well known. In this study, we aimed to determine if c-Met-activated mesenchymal stem cells (MSCs) pre-exposed to hypoxia promote therapeutic efficacy when transplanted to ischemic models, and whether c-Met interacts with cellular prion protein (PrP^C) present in the ischemic tissue. Methods: Western blot analysis was performed to determine the expression levels of PrP^C, C-caspase-3, and C-PARP-1, as well as the phosphorylation of Akt, p38, JNK, and BAX. A co-immunoprecipitation assay was performed to show that PrP^C binds with c-Met in vitro. An adhesion assay was performed to explore the alterations in MSCs attached to myoblasts (in vitro), and an invasion assay was performed to determine the effect on MSC invasion capacity upon interaction with myoblast-induced c-Met and PrP^C. CD31-positive capillaries and αSMA-positive arterioles in in vivo hindlimb ischemic tissue were quantified by immunofluorescence staining. The level of apoptosis in the tissue of each group was assessed by quantifying the number of C-caspase-3-positive cells. Finally, laser Doppler technology was utilized to detect the enhanced angiogenic effects in vivo. Results: We showed that hypoxic conditions increased PrP^C levels in vivo (hindlimb ischemic tissue) and in vitro (myoblasts) and increased c-Met levels in MSCs. To identify the relationship between c-Met from MSCs and PrP^C from myoblasts, we used a co-culturing system with myoblasts and MSCs pre-exposed to hypoxia. Hypoxia increased the phosphorylation of mitogen-activated protein kinases. Transplantation of hypoxia-pre-exposed MSCs to the ischemic site increased anti-apoptosis and enhanced the survival and proliferation of transplanted MSCs in a murine hindlimb model, resulting in improved functional recovery of the ischemic tissue. All the aforementioned effects were inhibited by the pretreatment of MSCs with the c-Met-neutralizing antibody Conclusion: c-Met-activated MSCs pre-exposed to hypoxia interact with PrP^C at the site of ischemic injury to increase the efficiency of MSC transplantation. Hence, our study demonstrated that c-Met is a potential target for MSC-based therapies.

The levels of mutant K-RAS and mutant N-RAS are rapidly reduced in a Beclin1 / ATG5 -dependent fashion by the irreversible ERBB1/2/4 inhibitor neratinib

ABSTRACTThe FDA approved irreversible inhibitor of ERBB1/2/4, neratinib, was recently shown to rapidly down-regulate the expression of ERBB1/2/4 as well as the levels of c-MET and mutant K-RAS via autophagic degradation. In the present studies, in a dose-dependent fashion, neratinib reduced the expression levels of mutant K-RAS or of mutant N-RAS, which was augmented in an additive to greater than additive fashion by the HDAC inhibitors sodium valproate and AR42. Neratinib could reduce PDGFRα levels in GBM cells, that was enhanced by sodium valproate. Knock down of Beclin1 or of ATG5 prevented neratinib and neratinib combined with sodium valproate / AR42 from reducing the expression of mutant N-RAS in established PDX and fresh PDX models of ovarian cancer and melanoma, respectively. Neratinib and the drug combinations caused the co-localization of mutant RAS proteins and ERBB2 with Beclin1 and cathepsin B. The drug combination activated the AMP-dependent protein kinase that was causal in enhancing HMG Co A reductase phosphorylation. Collectively, our data reinforce the concept that the irreversible ERBB1/2/4 inhibitor neratinib has the potential for use in the treatment of tumors expressing mutant RAS proteins.

NFE2L2/NRF2 silencing-inducible miR-206 targets c-MET/EGFR and suppresses BCRP/ABCG2 in cancer cells.

The nuclear factor (erythroid-derived 2)-like 2 (NFE2L2/NRF2) plays a critical role in the expression of multiple antioxidant and detoxifying enzymes. Herein, we provide evidence of the molecular links between NRF2 and oncogenic signaling hepatocyte growth factor receptor (HGFR/c-MET) and epidermal growth factor receptor (EGFR). Interfering RNA-induced stable inhibition of NRF2 in ovarian carcinoma SKOV3 and renal carcinoma A498 reduced the levels of c-MET and EGFR. MicroRNA-206 (miR-206) that was increased in both NRF2-silenced cells was predicted as a dual regulator of c-MET and EGFR. As experimental evidence, miR-206 decreased c-MET and EGFR levels through a direct binding to the 3′-untranslated region of the c-MET and EGFR genes. The treatment of NRF2-knockdown cells with the miR-206 inhibitor could restore c-MET and EGFR levels. The miR-206-mediated c-MET/EGFR repression resulted in two outcomes. First, presumably through the inhibition of c-MET/EGFR-dependent cell proliferation, overexpression of miR-206 inhibited tumor growth in SKOV3-inoculated nude mice. Second, reduced c-MET/EGFR in NRF2-silenced cells affected breast cancer resistance protein (BCRP/ABCG2) levels. The pharmacological and genetic inhibition of c-MET or EGFR, as well as the miR-206 mimic treatment, repressed BCRP levels and increased cellular accumulation of doxorubicin. In line with these, treatment of NRF2-silenced SKOV3 with the miR-206 inhibitor elevated BCRP levels and consequently made these cells more resistant to doxorubicin treatment. Collectively, our results demonstrated that the NRF2 silencing-inducible miR-206 targeted both c-MET and EGFR, and subsequently suppressed the BCRP level in cancer cells.

MiR-146a targets c-met and abolishes colorectal cancer liver metastasis

A major complication of colorectal cancer (CRC), one of the most frequent and deadly types of cancer, is disease progression via liver metastases. At this stage, very few treatment options are available for patients, and the disease remains incurable. Herein, we used a well-established mouse model of CRC liver metastasis (CLM) to identify new regulators of this process. Using serial transplantation of murine MC38 adenocarcinoma cells, we obtained liver metastatic variants that displayed extremely strong colonization abilities. Using these newly established cell lines, we performed gene expression arrays and microRNA (miR) profiling. Comparative and predictive analyses between the two arrays showed higher expression of c-met and concomitant reduction of miR-146a in the mestastatic variants. In CRC patients, expression levels of both c-met and miR-146a were similar between primary tumors and liver metastases. Interestingly, we identified c-met as a new target for miR-146a, as miR-146a was able to impede c-met translation. Of relevance, overexpression of miR-146a in metastatic clones showed reduced in vitro malignancy and abolished the development of primary tumor and liver metastases. Our results document a new mechanism for c-met regulation in CLM and highlight the crucial role of miR-146a in suppressing tumorigenesis.

Overexpression of miR-101 promotes TRAIL-induced mitochondrial apoptosis in papillary thyroid carcinoma by targeting c-met and MCL-1.

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) induces apoptosis in malignant cells, but not in normal cells. As papillary thyroid carcinoma cells broadly expressed TRAIL receptors (death receptor 4 and death receptor 5) on their surface, TRAIL is considered as a promising drug for treatment of papillary thyroid carcinoma. However, resistance to TRAIL still be a big obstacle to achieve a satisfactory effect for cancer therapy. Here, we found that overexpression of miR-101 was able to sensitize papillary thyroid carcinoma cells to TRAIL treatment in vitro and in vivo. Mechanically, we found that genes of c-met and MCL-1 were the targets of miR-101. Overexpression of miR-101 in TPC-1 significantly decreased the cellular protein levels of c-met and MCL-1, and thus inhibiting the PI3K/AKT pathway and reducing the resistance to TRAIL-induced mitochondrial apoptosis. Enforced expression of either c-met or MCL-1 could partially inhibit the miR-101 promoted apoptosis in TRAIL-treated TPC-1 cells. These results indicated that miR-101-c-met/MCL-1 axis determined the sensitivity of TRAIL to thyroid cancer in some extent. Combination with TRAIL and miR-101 may represent a novel approach to kill papillary thyroid carcinoma cells efficiently.

Abstract 4149: Increased migration ability of osimertinib-resistant EGFR-T790M mutant non-small-cell lung cancer cells

Abstract Background: A third generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) osimertinib is effective against gefitinib/erlotinib-resistant non-small-cell lung cancer (NSCLC) harboring EGFR T790M mutation. Although the majority of these patients initially responds to osimertinib, they eventually develop resistance. Acquired mutations such as EGFR C797S mutation have been reported to confer resistance to osimertinib, but mechanisms of resistance to osimertinib or biological behaviors of osimertinib-resistant NSCLC have not been fully elucidated. Materials and methods: Osimertinib-resistant PC-9/ZD/OR1 and PC-9/ZD/OR3 cells were generated after continuous exposure of gefitinib-resistant PC-9/ZD cells harboring both EGFR exon 19 deletion and T790M mutations to increasing concentrations of osimertinib. Growth-inhibitory effect of inhibitors gefitinib and osimertinib was evaluated by MTT assay. Common EGFR mutational status was examined by RainDrop Digital PCR System (RainDance Technologies). Immunoblot analysis was performed to investigate the modulation of molecules relevant to EGFR signaling pathways. Cell-adhesion assay, wound closure assay and transwell assay were performed to evaluate the ability of cell adhesion and migration. Results: Both PC-9/ZD/OR1 and PC-9/ZD/OR3 cells showed 50- to 120-fold more resistant to osimertinib than parental PC-9/ZD cells, and maintained resistance to gefitinib as well. PC-9/ZD/OR cells maintain EGFR exon 19 deletion and T790M mutations and C797S mutation was not detected. Although phosphorylation of EGFR and ERK1/2 were inhibited by osimertinib treatment in PC-9/ZD/OR cells, phosphorylation of Akt was not inhibited. PC-9/ZD/OR cells express the elevated level of c-MET and its phosphorylated form, suggesting that bypass signaling is activated to evade EGFR pathway blockade. PC-9/ZD/OR cells also express marked level of E-cadherin which parental PC-9/ZD cells do not express. PC-9/ZD/OR cells exhibited enhanced adherent activity, cell motility and migration ability compared to PC-9/ZD cells. Notably, osimertinib treatment significantly reduced the number of migrated cells not only in PC-9/ZD cells but also in PC-9/ZD/OR cells. These results suggest that osimertinib-resistant PC-9/ZD/OR cells acquired enhanced migration ability through c-MET pathway activation and/or induction of E-cadherin. Osimertinib treatment may be still effective to inhibit cell migration, suggesting that cell migration and cell growth are driven by different signaling pathways in PC-9/ZD/OR cells. Conclusion: c-MET overexpression was suggested to confer resistance to osimertinib and the resistant cells exhibited enhanced cell migration. Continuative osimertinib treatment may be beneficial in preventing metastasis even after the failure and involvement of c-MET and E-cadherin in osimertinib resistance should be further investigated. Citation Format: Satoshi Kambayashi, Yasuhiro Koh, Maiha Ohyama, Ayaka Tanaka, Hiroaki Akamatsu, Nahomi Tokudome, Hiroki Ueda, Nobuyuki Yamamoto. Increased migration ability of osimertinib-resistant EGFR-T790M mutant non-small-cell lung cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4149. doi:10.1158/1538-7445.AM2017-4149

Abstract 45: In vitro and in vivo activity of a novel c-Met-targeting antibody-drug conjugate using a DNA-alkylating, indolinobenzodiazepine payload

Abstract Purpose: c-Met dysregulation and/or overexpression are associated with tumor progression, metastasis and poor prognosis in numerous cancers. Despite strong pre-clinical evidence that blocking c-Met activity inhibits tumor cell growth and metastasis, targeted therapies have thus far failed to deliver an effective treatment option to the majority of patients. To address patients with both c-Met over-expressing and MET amplified tumors, we designed an antibody-drug conjugate (ADC) comprised of a humanized anti-c-Met monoclonal antibody linked to a highly potent indolinobenzodiazepine DNA-alkylating payload (DGN549) to enable activity against not only MET amplified but also c-Met over-expressing tumors. Experimental Design: Panels of monoclonal antibodies (Abs) against c-Met were generated and screened for antagonistic and agonistic activity in the presence or absence of the c-Met ligand, HGF. Lead Abs were humanized and conjugated to DGN549 either through lysine (Drug-to-Ab ratio (DAR) = 2.5) or engineered cysteine residues (DAR 2.0). Abs were also conjugated via lysine residues to the potent anti-microtubule maytansine derivative, DM4, using a sulfo-SPDB linker (DAR 3.5). Binding and cytotoxicity of ADCs were tested in vitro on normal and cancer cell lines with varying c-Met levels. Expression of c-Met was evaluated in patient tumors and xenografts along with normal human tissues using the CONFIRM immunohistochemistry assay. In vivo efficacy of anti-c-Met-DGN549 and anti-c-Met-DM4 ADCs was tested in both MET amplified and c-Met over-expressed (but non-amplified) xenograft tumor models. Results: A humanized anti-c-Met antibody, hucMet27, was identified which exhibits low c-Met agonist activity. Conjugates of hucMet27 were prepared with two different payloads, DGN549 and DM4, and in vitro and in vivo activity were determined. Both DGN549 and DM4 conjugates of hucMet27 bound with similar sub-nanomolar affinity to c-Met-expressing cells. hucMet27-DGN549 conjugates exhibited potent cytotoxicity against a large panel of c-Met expressing cell lines. By contrast, the potency of the hucMet27-DM4 conjugate was restricted mainly to cell lines harboring MET amplification, despite all cell lines demonstrating sensitivity to the unconjugated payload. When tested in mice bearing human xenograft tumors, both hucMet27-DGN549 and hucMet-DM4 conjugates were highly active in a MET amplified model, whereas hucMet27-DGN549 was more potent in inducing regressions in a model with c-Met over-expression without MET amplification. Conclusion: hucMet27-DGN549 exhibits compelling c-Met targeted anti-cancer activity in vitro and in vivo, and represents a promising therapeutic strategy to deliver a potent cytotoxic agent to tumor cells bearing a wide range of c-Met expression. Citation Format: Katharine C. Lai, Asli Muvaffak, Min Li, Marian Themeles, Surina Sikka, Kerry Donahue, Stuart W. Hicks, Angela Romanelli, Thomas Chittenden. In vitro and in vivo activity of a novel c-Met-targeting antibody-drug conjugate using a DNA-alkylating, indolinobenzodiazepine payload [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 45. doi:10.1158/1538-7445.AM2017-45

PD-L1 and c-MET expression and survival in patients with small cell lung cancer.

BackgroundBlocking the binding between the PD-1 and PD-L1 has been reported to produce antitumor responses. The MET/HGF axis appears to be another signaling pathway frequently altered in small cell lung cancer (SCLC). Our study was aimed to investigate the expression and prognostic roles of PD-L1 and c-MET in SCLC.MethodsThe expression levels of PD-L1 and c-MET were evaluated by immunohistochemical analysis in 83 SCLC specimens. Survival analysis was performed using the Kaplan-Meier method.ResultsOf the SCLC specimens, 51.8% and 25.3% exhibited positivity for PD-L1 and c-MET, respectively. Higher PD-L1 expression in tumor specimens was significantly correlated with a limited disease (LD) stage, normal levels of serum lactate dehydrogenase (LDH) and neuron-specific enolase (NSE). No association was found between the levels of c-MET and PD-L1 expression or between c-MET expression and other clinical characteristics. SCLC patients with PD-L1-positive tumors showed significantly longer overall survival (OS) than patients with PD-L1-negative tumors (17.0 vs 9.0, p=0.018). Conversely, those with positive c-MET expression exhibited a shorter OS trend (12.0 vs 15.0, p=0.186). However, sub-analysis of LD-stage patients revealed longer OS among the c-MET-negative group (25.0 vs 14.0; p=0.011). The OS of patients with positivity for both PD-L1 and c-MET showed no significant difference compared with other patients (p=0.17). According to multivariate analyses, neither PD-L1 nor c-MET immunoreactivity was a prognostic factor.ConclusionExpression of PD-L1 was correlated with LD stage and might serve as a prognostic for better OS in SCLC patients. In LD-stage patients, high c-MET expression might be predictive of a poor outcome.

The role of the HGF/c-Met signaling pathway in crizotinib-induced apoptosis in lung cancer with c-Met amplification ⁎

Abstract Objective This study aimed to study the role of the HGF/c-Met signaling pathway in crizotinib-induced apoptosis of various lung adenocarcinoma cell lines and xenograft tumor models. Methods In vitro, H2228, H1993, and A549 cells were treated with crizotinib. The inhibition of proliferation was quantitated by a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was quantified by flow cytometry. Expression of key proteins of the HGF/c-Met signaling pathway was examined by western blotting. In vivo, H1993 and A549 tumor cell xenograft models were established. Immunohistochemical analysis was used to determine protein expression of HGF and c-MET and the amount of phospho-c-MET (p-c-Met). Real-time quantitative polymerase chain reaction (PCR) was applied to examine the messenger RNA (mRNA) expression of c-MET and serine/ threonine protein kinase (AKT). The expression and activation of the key proteins were evaluated by western blotting. Results In vitro, the growth of H1993, H2228, and A549 cells was inhibited after crizotinib treatment for 72 h. Apoptotic rates of H1993 and H2228 cells increased with the crizotinib concentration and exposure time. In vivo, the growth-inhibitory rate of crizotinib for H1993 xenografts was 72.3%. Positive expression rates of HGF and c-MET in H1993 xenografts were higher than those in A549 xenografts; the p-c-MET amount was the largest in H1993 xenograft control but the lowest in the H1993 xenograft with crizotinib treatment. The mRNA expression levels of c-MET and AKT in H1993 xenografts were higher than those of A549 xenografts. The protein levels of c-MET, AKT, and extracellular regulated protein kinases (ERK) in H1993 xenografts were higher than those in A549 xenografts; the p-AKT amount was higher in H1993 xenograft control than in A549 xenografts; the largest amount of p-c-MET was detected in H1993 xenograft control; the amount of p-ERK was the lowest in the H1993 xenograft with crizotinib treatment. Conclusion The HGF/c-Met signaling pathway may mediate crizotinib-induced apoptosis and inhibition of proliferation of lung adenocarcinoma cells.

Hepatocyte growth factor/c-Met signaling pathway decreases doxorubicin sensitivity in hepatocellular carcinoma in vitro

Objective To explore the effect of hepatocyte growth factor (HGF)/c-Met signaling in doxorubicin (DOX) treatment of hepatocellular carcinoma (HCC). Methods Different biologic and genetic characteristics human HCC cell lines, Huh7, HepG2, MHCC97-L and MHCC97H were used in this experiment. Variation in c-Met mRNA expression level among different HCC cell lines was analyzed by RT-PCR. Western blot analysis was performed to detect c-Met and p-Met expression levels in these cell lines. CCK-8 experiment was carried to analyze the DOX sensitivity in various cell lines. t test and repeated measure analysis of variance were used for statistical analysis. Results Both c-Met and p-Met were overexpressed in MHCC97-L and MHCC97-H cell lines and these cell lines were resistant to DOX compared to Huh7 and HepG2. However, treatment of HGF in Huh7 and HepG2 cells activated c-Met signaling pathway and decreased the sensitivity of these two cell lines to DOX [inhibition rate: Huh7 (34.848±5.370) vs. (66.409±5.792) %, HepG2 (34.351±3.305) % vs. (62.308±5.453) %, both P = 0.002]. Whereas administration of c-Met inhibitor in MHCC97-L and MHCC97-H cell lines significantly increased the sensitivity to DOX [inhibition rate: MHCC97-L (73.106±3.472) % vs. (13.636±4.097) %; MHCC97-H (64.444±4.006) % vs. (6.296±2.796) %, both P < 0.001]. Conclusion HGF/c-Met signaling pathway is related the treatment efficacy of DOX in HCC. Key words: Carcinoma, hepatocellular; Hepatocyte growth factor; Doxorubicin; Signal transduction

Efficacy of regorafenib (REG) in patients with hepatocellular carcinoma (HCC) in the phase III RESORCE trial according to alpha-fetoprotein (AFP) and c-Met levels as predictors of poor prognosis.

4078 Background: REG is a multikinase inhibitor which improved overall survival (OS; HR 0.63, 95% CI 0.50, 0.79; P&lt;0.0001) and time to progression (TTP; HR 0.44, 95% CI 0.36, 0.55; P&lt;0.0001) compared with placebo in patients with HCC who progressed during prior sorafenib treatment in the RESORCE trial. This exploratory analysis evaluated the impact of baseline AFP and c-Met on REG treatment benefit (OS and TTP) in the RESORCE trial. Methods: Circulating AFP and c-Met protein (shed ectodomain) levels were quantified by a Luminex assay (Myriad RBM) in plasma samples collected at baseline from patients enrolled in the RESORCE trial. Valid biomarker data were available from 497 (AFP) and 499 (c-Met) out of 573 patients. Patients were subgrouped according to the median protein concentration (high vs low), and the treatment effect HR and its 95% CI were evaluated using a Cox proportional hazards model. The predictive effect was modeledas a protein–treatment interaction effect and subjected to Akaike information criterion (AIC)-based selection to assess its association with OS and TTP. Results: Baseline characteristics of patients were balanced across protein subgroups. While increased levels of both AFP (HR 1.09, 95% CI 1.07, 1.12; P&lt;0.001) and c-Met (HR 1.32, CI 95% 1.06, 1.63; P=0.011) were associated with a worse prognosis for OS, increased AFP levels were also associated with poor prognosis for TTP (HR 1.05, 95% CI 1.03, 1.07; P&lt;0.001). REG treatment benefit for both OS and TTP was independent of AFP and c-Met protein expression (Table). The protein–treatment interaction effect was not statistically significant. Conclusions: The treatment benefit of REG in patients with HCC was independent of AFP and c-MET protein expression at baseline. So far, no single protein has been associated with REG clinical benefit. Clinical trial information: NCT01774344. [Table: see text]

Migration of oral squamous cell carcinoma cells are induced by HGF/c-Met signalling via lamellipodia and filopodia formation.

The activation of receptor tyrosine kinases (RTKs) results in cellular effects including cell proliferation, survival, migration and invasion; RTKs also play an important role in tumourigenesis. It has been reported that EGFR signalling controls the migration of oral squamous cell carcinoma (OSCC) SAS and HSC3 cells but not of HSC4 cells, although the proliferation of HSC4 cells is regulated by EGF/EGFR. In the present study, we investigated the roles of EGFR and the c-Met signalling pathway in cell migration via filopodia and lamellipodia formation, which may be prerequisites for migration. To explore the role of c-Met in cell migration, we inhibited c-Met RTK activity using the c-Met inhibitor SU11274 and activated c-Met using hepatocyte growth factor (HGF) in three OSCC cell lines HSC4, SAS and Ca9-22 and investigated migration potency using a wound healing assay. We showed that inhibition of c-Met significantly suppressed, and activation of c-Met significantly promoted, the migration of OSCC cells. Additionally, the migration of SAS and Ca9-22 cells was inhibited by the EGFR inhibitors AG1478 and cetuximab and promoted by EGF treatment. Moreover, migration potency was correlated with lamellipodia formation. Furthermore, western blot analyses demonstrated that SU11274 decreased and HGF increased lamellipodin protein levels as well as phosphorylated c-Met levels. Collectively, we demonstrated that c-Met signalling induced lamellipodia formation by upregulating lamellipodin, thereby promoting the migration of OSCC cells.

The role of c-Met in prognosis and clinicopathology of renal cell carcinoma: Results from a single-centre study and systematic review

Background and objectivesThe c-Met proto-oncogene pathway plays an important role in the progression of various cancers. However, the effect of the c-Met pathway on renal cell carcinoma (RCC) remains controversial. We decided to clarify the role of c-Met in prognosis and clinicopathology of RCC. MethodsA total of 10 pairs of tumour and adjacent tissues were obtained from patients with primary RCC between 2013 and 2014 and tissue microarrays to assess c-Met expression in tumour tissues from 90 patients with RCC by Western blot and immunohistochemical staining. We also presented a meta-analysis to explore the correlation between c-Met and pathological grade and stage of RCC. The two-tailed Pearson’s χ2 and Fischer exact tests were used to compare categorical variables. Multivariate analysis was performed using the multivariate Cox proportional hazards model. ResultsC-Met protein levels were increased in 8 of 10 RCC tissue samples compared with their adjacent normal tissue and c-Met expression levels were positively associated with a high nuclear grade (P = 0.008) and pT stage (P = 0.002). Multivariate analysis showed that a high expression of c-Met was an independent predictor of disease-specific survival (P = 0.017). A meta-analysis found that increased c-Met expression in RCC tissues was closely correlated with high tumour grade (P<0.001) and high pT stage (P = 0.001). Most importantly, c-Met expression was significantly correlated with disease-specific survival (P<0.001). ConclusionsBecause c-Met is strongly associated with pathological grade, stage and disease-specific survival, c-Met levels may have potential to predict patient prognosis and to guide clinical diagnosis and treatment.