c-Met Overexpression Research Articles

C-MET Overexpression in Colorectal Cancer: A Poor Prognostic Factor for Survival

IntroductionIncreased mesenchymal-epithelial transition factor gene (c-MET) expression in several human malignancies is related to increased tumor progression and is a new potential drug target for several types of cancers. In the present study, we investigated the incidence of c-MET overexpression and its prognostic significance in patients with colorectal cancer (CRC). Patients and MethodsWe retrospectively reviewed the data from 255 stage IV CRC patients who had results from a c-MET immunohistochemical test at Samsung Medical Center. We explored the relationships between c-MET overexpression and clinicopathological features and survival. ResultsPrimary tumor sites were 67 right-sided colon, 98 left-sided colon, and 90 rectum. Forty-two patients (16.7%) had poorly differentiated or mucinous carcinoma. Among the 255 patients, 39 (15.3%) exhibited c-MET overexpression. There was no significant difference in the prevalence of c-MET overexpression according to primary site, histologic differentiation, molecular markers, or metastatic sites. In a comparison of the tumor response to first-line chemotherapy according to the level of c-MET expression, we found no significant difference in either partial response or disease control rate. In the survival analysis, patients with c-MET overexpression had significantly shorter overall survival (39 vs. 27 months; P = .018) and progression-free survival (PFS) during bevacizumab treatment (10 vs. 7 months; P = .024). Conclusionc-MET overexpression, which was detected in 39 CRC patients (15.3%) irrespective of primary sites or molecular markers, indicated a poor survival prognosis and predicted shorter PFS during bevacizumab treatment in patients with CRC. Further studies are warranted to elucidate the value of c–MET-targeted therapy in CRC patients.

A Prospective Observational Study Evaluating the Correlation of c-MET Expression and EGFR Gene Mutation with Response to Erlotinib as Second-Line Treatment for Patients with Advanced/Metastatic Non-Small-Cell Lung Cancer

Objectives: We aimed to evaluate the prevalence and predictive role of c-MET expression and EGFR mutation in the efficacy of erlotinib in non-small-cell lung cancer (NSCLC). Methods: We prospectively recruited 196 patients with stage IV or recurrent NSCLC treated with erlotinib after failure of first-line chemotherapy. Immunohistochemistry was used to evaluate c-MET overexpression, silver in situ hybridization (SISH) to assess gene copy number, and real-time polymerase chain reaction to detect EGFR mutations, respectively, in tumor tissue. Results: The major histologic type was adenocarcinoma (66.8%). c-MET was overexpressed in 55.8% (87/156) and dominant in females as well as non-squamous histology. Although c-MET gene amplification and high polysomy were observed in 2.0% (3/152) and 11.2% (17/152), they did not correlate with any characteristics. EGFR mutation was detected in 13.1% (20/153). The objective response rate of erlotinib was higher (61.1 vs. 3.7%, p < 0.001) and the median progression-free survival (PFS) was longer (10.2 vs. 1.9 months, p < 0.001) in EGFR-sensitizing mutations. However, c-MET positivity did not show a significant correlation with response to erlotinib or PFS. Conclusion: We reconfirmed EGFR mutation as a strong predictive marker of NSCLC. However, c-MET positivity was not associated with response or PFS, although c-MET overexpression correlated with some clinical characteristics.

Forty-nine gastric cancer cell lines with integrative genomic profiling for development of c-MET inhibitor.

Receptor tyrosine kinase MET (c-MET) has received considerable attention as a potential target for gastric cancer (GC) therapy and a number of c-MET inhibitors have been developed. For successful drug development, proper preclinical studies especially using patient derived cancer cell lines are very important. We profiled MET and MET-related characteristics in 49 GC cell lines to utilize them as models in preclinical studies of GC. Forty-nine cell lines were analyzed for genetic, biological, and molecular status to characterize MET and MET-related molecules. Four c-MET inhibitors were tested to elucidate the dependency on MET pathway in the 49 GC cell lines. Six of 49 cell lines were MET amplified with overexpression of c-MET and p-MET. The variants of MET were not associated with c-MET expression or amplification. Hs746T showed an exon 14 deletion in conjunction with MET amplification. The cell lines were divided into 6 MET amplified, 2 c-MET overexpressed, 2 hepatocyte growth factor (HGF) overexpressed, and 39 MET-negative subgroups. Except tivantinib, the c-MET inhibitors showed higher inhibition (%) in MET amplified than in MET nonamplified cell lines that MET amplified cell lines showed MET pathway dependency. However, the c-MET overexpressed and HGF overexpressed cell lines showed moderate dependency on MET pathway. Well-characterized cell lines are very important in studying drug development. Our 49 GC cell lines had various characteristics of MET and MET-related molecules and MET pathway dependency. These provide a promising platform for development of various RTK inhibitors including c-MET inhibitors.

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.

Synergistic antitumor effects of cMet inhibitor in combination with anti-VEGF in colorectal cancer patient-derived xenograft models.

cMet signaling pathway is involved in the resistance to anti-VEGF therapy and cMet overexpression is associated with tumor progression and poor prognosis. In this study, the expression of cMet in 146 Chinese colorectal cancer (CRC) patients was examined by immunohistochemistry staining. Our data demonstrated that cMet overexpression rate was 42.5% (62/146) and cMet overexpression was closely correlated with distant metastasis of CRC. Using CRC patient-derived xenograft (PDX) mouse models we investigated antitumor activity of a novel selective cMet inhibitor volitinib alone or in combination with anti-VEGF inhibitor apatinib in vivo. Our results showed that combination treatment significantly inhibited tumor growth in two PDX models. While volitinib treatment alone induced moderate improvement in tumor growth inhibition, combination treatment synergistically reduced microvessel density, suppressed proliferation, and increased apoptosis in PDX models. Further analysis showed synergistic inhibition of MAPK and PI3K/Akt pathways by volitinib and apatinib. Taken together, our data provide a rationale to targeting both cMet and VEGF in the treatment of cMet overexpressing CRC in clinical trials.

Prognostic impact of high c-Met expression in ovarian cancer: a meta-analysis.

High c-Met expression has been observed in epithelial ovarian cancer (EOC). However, its clinicopathological impacts remain controversial. We conducted this meta-analysis to evaluate the pathologic and prognostic significance of c-Met overexpression in patients with EOC. A systematic computerized search of the electronic databases PubMed, PMC, EMBASE, and Google scholar (up to April 2018) was carried out. From seven studies, 568 patients with EOC were included in the meta-analysis. Although there was no statistical significance, EOCs with c-Met overexpression tended to show higher FIGO stage (III-IV) (odds ratio = 2.18, 95% confidence interval: 0.86-5.53, p = 0.10) and higher rate of lymph node metastasis (odds ratio = 3.05, 95% confidence interval: 0.85-10.98, p = 0.09), compared with tumors with low c-Met expression. In terms of prognosis, patients with c-Met-high EOC showed significantly worse survival than those with c-Met-low tumor (hazard ratio = 2.11, 95% confidence interval: 1.51-2.94, p < 0.0001). In conclusion, this meta-analysis indicates that high c-Met expression represents an adverse prognostic marker for patients with EOC.

Human epidermal growth factor receptor 2, epidermal growth factor receptor, and c-MET overexpression and survival in biliary tract cancer: A meta-analysis.

Tyrosine kinase growth factor receptors (TKGFRs) play an important role in the progression of cancer. A variety of studies have investigated the clinicopathologic correlation of these receptors and their influences on patient survival in different types of cancer. As the members of TKGFRs, the biomarkers c-MET, epidermal growth factor receptor (EGFR), and human epidermal growth factor receptor 2 (HER-2) have been extensively investigated in biliary tract cancer (BTC). However, their prognostic value is still controversial. Our study aimed to evaluate the prognostic significance of the three markers in BTC patients based on the published studies. The correlation between high expression of these markers and clinical parameters or overall survival (OS) has been assumed in this paper. Including PubMed, EMBASE, China National Knowledge Infrastructure, and Springer, a comprehensive search for the related literature published in Chinese and English has been done. Finally, 31 studies were selected in our research. Surprisingly, the meta-analysis indicated that HER-2 high expression was not correlated with age, gender, primary tumor, tumor node metastasis (TNM) stage, lymph node status, and differentiation. We also found that EGFR high expression was not associated with the parameters, such as age, gender, TNM stage, differentiation, or lymph node status. c-MET high-expression was not associated with age, differentiation, gender, TNM stage, or lymph node status. In addition, our study showed that HER-2, EGFR, and c-MET high expression had an adverse influence on OS in BTC, the pooled hazard ratio for HER-2, EGFR, and c-MET was statistically significant. The present meta-analysis indicated that EGFR and HER-2 high expression have little impact on OS in patients with BTC while c-MET high expression influenced OS in patients with BTC to a large extent. However, c-MET, EGFR, and HER-2 expression did not show any correlation with those clinical parameters. c-MET may be a potential therapeutic target for BTC.

Loss of Pten synergizes with c-Met to promote hepatocellular carcinoma development via mTORC2 pathway

Hepatocellular carcinoma (HCC) is a deadly malignancy with limited treatment options. Activation of the AKT/mTOR cascade is one of the most frequent events along hepatocarcinogenesis. mTOR is a serine/threonine kinase and presents in two distinct complexes: mTORC1 and mTORC2. While mTORC1 has been extensively studied in HCC, the functional contribution of mTORC2 during hepatocarcinogenesis has not been well characterized, especially in vivo. Pten expression is one of the major mechanisms leading to the aberrant activation of the AKT/mTOR signaling. Here, we show that concomitant downregulation of Pten and upregulation of c-Met occurs in a subset of human HCC, mainly characterized by poor prognosis. Using CRISPR-based gene editing in combination with hydrodynamic injection, Pten was deleted in a subset of mouse hepatocytes (sgPten). We found that loss of Pten synergizes with overexpression of c-Met to promote HCC development in mice (sgPten/c-Met). At the molecular level, sgPten/c-Met liver tumor tissues display increased AKT and mTOR signaling. Using Rictor conditional knockout mice, we demonstrate that sgPten/c-Met-driven HCC development strictly depends on an intact mTORC2 complex. Our findings therefore support the critical role of mTORC2 in hepatocarcinogenesis. sgPten/c-Met mouse model represents a novel valuable system that can be used for the development of targeted therapy against this deadly malignancy.

C-Met Overexpression in Cervical Cancer, a Prognostic Factor and a Potential Molecular Therapeutic Target.

This study aimed to assess the association between pretreatment c-Met overexpression in local-regional advanced cervical cancer patients treated definitively with concurrent chemoradiation therapy (CRT) and treatment outcomes including overall survival (OS), progression-free survival (PFS), distant metastases (DM) control, and local-regional control (LC). This Institutional Review Board-approved study included cervical cancer patients treated definitively and consecutively with CRT. Evaluation of cytoplasmic immunoreactivity for c-Met was performed and scored semiquantitatively by 3 pathologists, blinded to the treatment outcomes, and incorporated both the intensity and percentage of immunoreactivity in invasive carcinoma (H score). Treatment outcomes were reviewed and reported. Outcomes were stratified by c-Met overexpression and tumor characteristics. OS, PFS, LC, and DC rates were obtained via the Kaplan-Meier method and differences between groups were evaluated by the log-rank test. Hazard ratios were obtained via Cox regression for both univariate and multivariate analyses. The 5-year OS, PFS, LC, and DC were 57.18%, 48.07%, 72.11%, and 62.85%, respectively. Ten (35.7%) and 18 patients (64.3%) had c-Met H index >30 and<30, respectively. c-Met overexpression was significantly associated with worse 3- and 5-year OS (P=0.003), PFS (P=0.002), LC (P=0.01), and DC (P=0.0003). Patients with c-Met overexpression had a hazard ratio of 6.297, 5.782, 6.28, and 18.173 for the risks of death, disease progression, local recurrence, and DM, respectively. c-Met overexpression could be a potential predictive marker and therapeutic target for local-regional advanced cervical cancer patients treated definitively with CRT.

The Prognostic Significance of c-MET and EGFR Overexpression in Resected Gastric Adenocarcinomas.

Epidermal growth factor receptor (EGFR) and c-MET are tyrosine kinase growth factor receptors implicated in gastric cancer (GC), and their pathways appear to be interdependent. The aim of this study was to investigate the prognostic value of EGFR and c-MET protein overexpression by immunohistochemistry in Canadian patients with resected GC and correlate it with clinicopathologic characteristics and overall survival (OS). Tissue microarray blocks were constructed from 120 resected GCs stained with EGFR and c-MET and scored semiquantitatively (0 to 3+). Each receptor's expression was compared with clinicopathologic characteristics and survival. Descriptive statistics, Kaplan-Meyer, and Cox regression were used for statistical analyses. Of the 113 interpretable cases, overexpression of EGFR and c-MET was noted in 17 (15%) and 65 (57%), respectively; coexpression of EGFR and c-MET was observed in 12 (10%) of GC. EGFR and c-MET overexpression correlated with poor OS: median 13 versus 30 months in EGFR positive versus negative GC (hazard ratio [HR]=1.67, P=0.11); 27 versus 49 months in c-MET positive versus negative GC (HR=1.17, P=0.49), respectively. GC coexpressing EGFR and c-MET was significantly correlated with poor survival: 12 versus 29 months in double-positive versus rest of tumors both in univariate (HR=2.62, P=0.003) and multivariate analyses (HR=2.58, P=0.01). This study describes the prevalence and prognostic value of EGFR and c-MET in a Canadian population of patients undergoing curative intent resection for GC. Both c-MET and EGFR overexpression trended toward poor OS, but only the group with EGFR+/c-MET+ GC reached statistical significance on multivariate analysis.

Clinical and prognostic value of the C-Met/HGF signaling pathway in cervical cancer.

Aberrant activation of the HGF/c-Met signalling pathway is reported to be associated with cell proliferation, progression, and metastasis features of several tumor types, including cervical cancer, suggesting that it may be of potential value as a novel therapeutic target. Furthermore, HPV-positive patients had a higher serum level of HGF or c-Met protein, compared with HPV-negative patients. c-Met or HGF overexpression in lesions of cervical cancer is reported to be related to a poorer prognosis, and hence this may be of value as a prognostic and predictive biomarker. Several approaches have been developed for targeting HGF and/or c-Met. One of these is crizotinib (a dual c-Met/ALK inhibitor). This has been approved by FDA for the treatment of lung-cancer. Further investigations are required to evaluate and optimize the use of c-Met inhibitors in cervical cancer or parallel targeting signalling pathway associated/activated via MET/HGF pathway. The main aim of current review was to give an overview of the potential of the c-Met/HGF pathway as a prognostic, or predictive biomarker in cervical cancer.

Primary Amine-Clustered DNA Aptamer for DNA-Protein Conjugation Catalyzed by Microbial Transglutaminase.

DNA-protein conjugates are promising biomolecules for use in areas ranging from therapeutics to analysis because of the dual functionalities of DNA and protein. Conjugation requires site-specific and efficient covalent bond formation without impairing the activity of both biomolecules. Herein, we have focused on the use of a microbial transglutaminase (MTG) that catalyzes the cross-linking reaction between a glutamine residue and a primary amine. In a model bioconjugation, a highly MTG-reactive Gln (Q)-donor peptide (FYPLQMRG, FQ) was fused to enhanced green fluorescent protein (FQ-EGFP) and a primary amine-clustered DNA aptamer was enzymatically synthesized as a novel acyl-acceptor substrate of MTG, whose combination leads to efficient and convenient preparation of DNA-protein conjugates with high purity. Dual functionality of the obtained DNA-EGFP conjugate was evaluated by discrimination of cancer cells via c-Met receptor recognition ability of the DNA aptamer. The DNA aptamer-EGFP conjugate only showed fluorescence toward cells with c-Met overexpression, indicating the retention of the biochemical properties of the DNA and EGFP in the conjugated form.

P3.03-031 Response to Crizotinib Can Occur in C-MET Overexpression NSCLC Independent of MET exon14 Alterations After First-Line EGFR-TKI Resistance

Although non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations are responsive to EGFR-tyrosine kinase inhibitors (EGFR-TKIs), drug resistances are always inevitable. Concurrent multiple mutations and bypass mechanisms both can contribute to development of resistance to EGFR-TKIs. Preclinical and clinical evidences suggest a role for MET activation as a secondary driver of resistance to targeted therapy. Activation of the MET pathway can occur through a diverse set of mechanisms including MET amplification, MET exon 14 alterations, MET overexpression.

Clinicopathological impacts of high c-Met expression in head and neck squamous cell carcinoma: a meta-analysis and review.

High c-Met expression has been observed in head and neck squamous cell carcinoma (HNSCC). However, its clinicopathological impact remains controversial. We performed this meta-analysis to evaluate the pathologic and prognostic impacts of c-Met overexpression in patients with HNSCC. A systematic computerized search of the electronic databases was carried out. From 16 studies, 1,948 patients with HNSCC were included in the meta-analysis. Compared with HNSCCs showing low c-Met expression, tumors with high c-Met expression were significantly associated with higher rate of lymph node metastasis (odds ratio = 3.26, 95% CI: 2.27–4.69, P < 0.00001) and higher T stage (odds ratio = 1.33, 95% CI: 1.03–1.71, P = 0.03). In addition, patients with c-Met-high HNSCC showed significantly worse disease-free survival (hazard ratio = 1.49, 95% CI: 1.04–2.14, P = 0.03) and overall survival (hazard ratio = 1.83, 95% CI: 1.29–2.60, P = 0.0007) than those with c-Met-low tumor. In conclusion, this meta-analysis demonstrates that high c-Met expression is significantly associated with worse pathological features and prognosis, indicating c-Met overexpression is an adverse prognostic marker for patients with HNSCC.

Clinicopathological impacts of high c-Met expression in renal cell carcinoma: a meta-analysis and review.

c-Met overexpression has been observed in renal cell carcinoma (RCC). However, its clinicopathological impacts remain uncertain. We performed this meta-analysis to evaluate the pathologic and prognostic impacts of high c-Met expression in patients with RCC. A systematic computerized search of the electronic databases PubMed and Embase was performed. From 12 studies, 1,724 patients with RCC were included in the meta-analysis. Compared with RCCs showing low c-Met expression, tumors with high c-Met expression showed significantly higher nuclear grade (odds ratio = 2.45 [95% CI: 1.43–4.19], P = 0.001) and pT stage (odds ratio = 2.18 [95% CI: 1.27–3.72], P = 0.005). In addition, patients with c-Met-high RCC showed significantly worse overall survival than those with c-Met-low tumor (hazard ratio = 1.32 [95% CI: 1.12–1.56], P = 0.0009). In conclusion, this meta-analysis demonstrates that high c-Met expression correlate with significantly worse pathological features and overall survival, indicating c-Met overexpression is a potential adverse prognostic marker for patients with RCC.

Preclinical rationale for combination of crizotinib with mitomycin C for the treatment of advanced colorectal cancer

ABSTRACTColorectal cancer (CRC) is a leading cause of cancer-related deaths in the United States. We analyzed 26 MSI-High and 558 non-MSI-High CRC tumors. BRCA2 mutations were highly enriched (50%) in MSI-High CRC. Immunohistochemistry showed that BRCA2-mutated MSI-High CRC had high c-MET (64%) expression compared with BRCA-WT (17%). We hypothesized a mechanistic link between BRCA2-deficiency and c-MET overexpression and synergistic interaction between drugs that treat BRCA-deficient tumors (mitomycin C (MMC) or PARP inhibitors) and c-MET inhibitors (crizotinib). We tested CRC cell lines for sensitivity to MMC plus crizotinib or other drug combinations including PARP-inhibitors. Combined treatment of tumor cells with crizotinib and MMC led to increased apoptosis as compared with each drug alone. Additionally, combination treatment with increasing concentrations of both drugs demonstrated a synergistic anti-cancer effect (CI = 0.006–0.74). However, we found no evidence for c-MET upregulation upon effective BRCA2 knockdown in tumor cells −/+DNA damage. Although we found no mechanistic link between BRCA2 deficiency and c-MET overexpression, c-MET is frequently overexpressed in CRC and BRCA2 is mutated especially in MSI-H CRC. The combination of crizotinib with MMC appeared synergistic regardless of MSI or BRCA2 status. Using an in-vivo CRC xenograft model we found reduced tumor growth with combined crizotinib and MMC therapy (p = 0.0088). Our preclinical results support clinical testing of the combination of MMC and crizotinib in advanced CRC. Targeting cell survival mediated by c-MET in combination with targeting DNA repair may be a reasonable strategy for therapy development in CRC or other cancers.

Prognostic value of c-Met overexpression in pancreatic adenocarcinoma: a meta-analysis

The overexpression of c-Met protein has been detected in pancreatic adenocarcinoma (PAC). However, its prognostic impact remains unclear. We performed this meta-analysis to evaluate the prognostic value of c-Met overexpression in PAC. A systematic computerized search of the electronic databases such as PubMed, Embase, and Google Scholar was carried out. From 5 studies, 423 patients who underwent surgical resection for PAC were included in the meta-analysis. Compared with patients with PAC showing low c-Met expression, patients with c-Met-high tumor had significantly worse disease-free survival (hazard ratio = 1.94 [95% confidence interval, 1.46–2.56], P = 0.00001) and overall survival (hazard ratio = 1.86 [95% confidence interval, 1.19–2.91], P = 0.006). In conclusion, this meta-analysis demonstrates that c-Met overexpression is a significant prognostic marker for poor survival in patients who underwent surgical resection for PAC.

Prognostic value of c-Met overexpression in hepatocellular carcinoma: a meta-analysis and review.

The overexpression of c-Met protein has been detected in hepatocellular carcinoma (HCC). However, its prognostic impact remains uncertain. We performed this meta-analysis to evaluate the prognostic value of c-Met overexpression in patients who underwent curative surgical resection for HCC. A systematic computerized search of the electronic databases was carried out. From 5 studies, 1,408 patients who underwent surgical resection for HCC were included in the meta-analysis. Compared with patients with HCC having low c-Met expression, patients with c-Met-high tumor showed significantly worse relapse-free survival (hazard ratio = 1.26 [95% confidence interval, 1.02–1.56], P = 0.03) and overall survival (hazard ratio = 1.16 [95% confidence interval, 1.03–1.31], P = 0.01). In conclusion, our meta-analysis indicates that c-Met overexpression is a significant adverse prognostic factor for recurrence and survival in patients who underwent surgical resection for HCC.

Overexpression of c-Met in bone marrow mesenchymal stem cells improves their effectiveness in homing and repair of acute liver failure

BackgroundTransplantation of bone marrow-derived mesenchymal stem cells (BMSCs) has emerged as a novel therapy for acute liver failure (ALF). However, the homing efficiency of BMSCs to the injured liver sites appears to be poor. In this study, we aimed to determine if overexpression of c-Met in BMSCs could promote the homing ability of BMSCs to rat livers affected by ALF.MethodsOverexpression of c-Met in BMSCs (c-Met-BMSCs) was attained by transfection of naive BMSCs with the lenti-c-Met-GFP. The impact of transplanted c-Met-BMSCs on both homing and repair of ALF was evaluated and compared with lenti-GFP empty vector transfected BMSCs (control BMSCs).ResultsAfter cells were transfected with the lenti-c-Met-GFP vector, the BMSCs displayed very high expression of c-Met protein as demonstrated by Western blot. In addition, in vitro transwell migration assays showed that the migration ability of c-Met-BMSCs was significantly increased in comparison with that of control BMSCs (P < 0.05), and was dependent on hepatocyte growth factor (HGF). Furthermore, rats with ALF that received transplanted c-Met-BMSCs showed significantly improved homing ability to the injured liver; this was accompanied by elevated survival rates and liver function in the ALF rats. Parallel pathological examination further confirmed that transplantation of c-Met-BMSCs ameliorated liver injury with reduced hepatic activity index (HAI) scores, and that the effects of c-Met-BMSCs were more profound than those of control BMSCs.ConclusionsOverexpression of c-Met promotes the homing of BMSCs to injured hepatic sites in a rat model of ALF, thereby improving the efficacy of BMSC therapy for ALF repair.

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