Search

Aberrant hepatocyte growth factor (HGF)/MET signaling has been implicated in hepatocarcinogenesis, suggesting that MET may serve as an attractive therapeutic target in hepatocellular carcinoma. We sought to investigate the in vitro and in vivo antitumor activity of AMG 337, a potent and highly selective small molecule MET kinase inhibitor, in preclinical models of hepatocellular carcinoma. The antiproliferative activity of AMG 337 was evaluated across a panel of hepatocellular carcinoma cell lines in a viability assay. Daily oral administration was used to evaluate the in vivo antitumor activity of AMG 337 in two patient-derived xenograft (PDX) models of hepatocellular carcinoma (LI0612 and LI1078). AMG 337 exerted potent antiproliferative activity against 2 of 40 hepatocellular carcinoma cell lines, namely, MHCC97H (IC50, 0.015 μmol/L) and HCCLM3 (IC50, 0.025 μmol/L). Both sensitive cell lines showed MET amplification (MET/CEN-7 >2.0) assessed by FISH, and high MET expression (3+ IHC) assessed by IHC. AMG 337 potently inhibited p-MET in all cell lines with detectable levels of total MET. However, the dose-dependent inhibition of downstream effectors of HGF/MET signaling, including p-GAB1, p-AKT, and p-ERK, was limited to those cell lines sensitive to AMG 337 in a viability assay (MHCC97H and HCCLM3). AMG 337 significantly inhibited tumor growth at all doses tested in the MET-amplified and MET-high–expressing hepatocellular carcinoma PDX model LI0612 and had no effect on tumor growth in the non-MET–amplified and MET-low–expressing hepatocellular carcinoma PDX model LI1078. AMG 337 represents a promising and novel therapeutic strategy for targeting hepatocellular carcinomas with a dependence on HGF/MET signaling. Mol Cancer Ther; 15(6); 1227–37. ©2016 AACR.

MET and its sole ligand, hepatocyte growth factor (HGF), are promising targets in gastric and gastroesophageal junction cancer. We evaluated whether MET protein expression or MET gene amplification is prognostic for overall survival (OS) in Chinese patients with advanced gastric or gastroesophageal junction cancer. Archival formalin-fixed, paraffin-embedded tumor samples from patients with unresectable locally advanced or metastatic gastric or gastroesophageal junction cancer enrolled in clinical trials at Peking University Cancer Hospital from 2008 to 2010 were assessed for MET and phospho-MET (p-MET) expression by immunohistochemistry and MET amplification by FISH. MET-positive expression was defined as membrane protein staining in ≥25% of tumor cells. MET amplification was defined as MET:centromere 7 ratio >2.0. We tested the association of MET status with clinical characteristics and OS, and also evaluated the association between expression and amplification. One hundred sixty-eight patients were eligible. Of the evaluable samples, 53 of 137 (39%) were MET positive, eight of 134 (6%) were p-MET positive, and eight of 113 (7%) were MET amplified. Neither MET expression nor MET amplification were associated with clinical characteristics, except Lauren classification (P = 0.04); MET amplification was associated with diffuse type. No significant OS difference was observed between MET-positive and MET-negative populations, regardless of first-line chemotherapy received. In 95 evaluable patients, MET expression was significantly associated with MET amplification (P < 0.001); all MET-amplified tumor samples showed some MET expression. In 96 evaluable patients, p-MET positivity was significantly associated with MET amplification (P < 0.001). Further evaluation in larger and independent sample sets is warranted to confirm our findings. Mol Cancer Ther; 14(11); 2634–41. ©2015 AACR.

Introduction B cell acute lymphoblastic leukemia (B-ALL) is a severe disease caused by malignant transformation and uncontrolled proliferation of immature B lymphocytes. Blinatumomab, a Bi-specific T cell engager (BiTE®) combining the VH and VL domains of two antibodies against human CD19 and CD3, has been approved by U.S. Food and Drug Administration (FDA) for the treatment of Philadelphia chromosome negative (Ph-) relapsed or refractory B-ALL in 2014, and recently Philadelphia chromosome-positive (Ph+) B-ALL. Blinatumomab brings killer T and target B cells into close proximity, activating patients' autologous T cells to kill both normal and malignant B cells via mechanisms such as cytolytic immune synapse formation and inflammatory cytokine production. Clinical trials have shown that there are still patients refractory to blinatumomab. It is thus of great importance to understand the resistance mechanisms and search for biomarkers for patient selection. Methods and Results In this study, we used Mass cytometry-based immunophenotyping and Luminex based multiple protein quantitation, to search for biomarkers correlated with the killing capacity of blinatumomab. First, we collected PBMCs from 12 B-ALL patients for an in vitro killing assay, focusing on the quantity and quality profiling of T cells. PBMCs were used as the effector cells and NALM-6 as the target cells. The final effector to target (E/T) ratio is 10:1. Blinatumomab were added to the co-cultured cells (final concentration 10 ng/mL) for 18hrs. A 5% specific lysis of NALM-6 was used as cut-off threshold. Samples with specific killing above 5% were classified as "positive" for blinatumomab response, and below 5% as "negative". Among the patients analyzed, 4 out of 12 patients (33.3%) showed apparent and specific lysis of NALM6 leukemia cells, while the remaining samples showed no obvious effect. This divergent killing effect of blinatumomab with the presence of PBMCs from different donors may reflect the differentiated treatment response in B-ALL patients. Concurrently we immunophenotyped each patient's PBMCs by Mass cytometry with a panel of antibodies for surface lineage markers and intracellular effector molecules and cytokines /chemokines. Unsupervised clustering showed that a panel of T-cell associated biomarkers highly significantly correlated with B-ALL cell response to blinatumomab (p=0.001, R=0.839). This panel of biomarkers included T cell markers of CD45, CD3 and CD4; cytolytic proteins of Perforin and GranzymeB; cytokines of IL-2, INFγ and TNFα; and chemokine CCL4 (also known as MIP-1b). In a Luminex analysis examining multiple proteins accumulating in the culture supernatant from the in vitro killing assay, the top biomarkers identified by Mass cytometry also showed significant response to blinatumomab at different time points (12, 24 and 48 hrs). They included TNF-α, CCL4, IL-2, INFγ and Granzyme B. Furthermore, released CCL4 at 24 and 48 hrs and INFγ at 48 hrs significantly correlated with blinatumomab mediated cytotoxicity. Conclusion In summary, the immunophenotyping and multiplexed protein measurement by Mass cytometry and Luminex assay identified key biomarkers that may correlate with blinatumomab-mediated killing of B-ALL leukemia cells. The biomarker panel reflected the importance of primed T cell activation, associated key cytokine/chemokine as well as the consequent cytolytic protein release in the overall response to blinatumomab. Thus, in vitro biomarker profiling focusing on T cell status with these key molecules may facilitate patient selection and predict the response to the immunotherapy. Disclosures Fu: Amgen: Research Funding.

e15538Background: Gastric cancer is a heterogeneous disease. Whether the expression and amplification of c-Met/HER2 differ between the primary and metastatic lesion and their impacts on prognosis r...

Purpose: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. Aberrant hepatocyte growth factor / MET signaling has been implicated in hepatocarcinogenesis, suggesting that MET may serve as an attractive therapeutic target in HCC. The purpose of this study was to investigate the anti-tumor activity in vitro and in vivo of AMG 337, a potent and highly selective small molecule MET kinase inhibitor, in preclinical models of HCC. Experimental Design: The anti-proliferative activity of AMG 337 was evaluated across a panel of 40 HCC cell lines in a 72-hour viability assay. Daily oral administration of AMG 337 at doses of 3, 10 and 30 mg/kg was used to evaluate the in vivo anti-tumor activity of AMG 337 in two patient-derived mouse xenograft (PDX) models of HCC, LI0612 and LI1078. Effects on MET signaling were assessed by western blot analysis of downstream effector proteins including p-GAB1, p-AKT and p-ERK. MET protein levels and gene copy number for both PDX models and a subset of HCC cell lines were assessed by immunohistochemistry (IHC; Dako) and fluorescence in situ hybridization (FISH; Dako), respectively. High MET expression was defined as the presence of any tumor cells with membrane staining at 3+ intensity. MET amplification was defined as MET:CEN-7 ratio >2.0 or MET SNP array log2 copy number >2.5. Results: AMG 337 displayed potent anti-proliferative activity in two of 40 HCC cell lines (MHCC97H and HCCLM3) (IC50 0.015 μM and 0.025 μM, respectively); both cell lines were amplified for MET (MET/CEN-7 >2.0) and showed high MET expression (3+ IHC). AMG 337 potently inhibited p-MET in all cell lines with detectable levels of total MET. However, dose-dependent inhibition of p-GAB1, p-AKT and p-ERK was limited to those cell lines that were sensitive to AMG 337 in viability assays. AMG 337 significantly inhibited tumor growth at all doses tested (p < 0.001) in the MET-amplified and MET-high expressing HCC PDX model LI0612. However, AMG 337 had no effect on tumor growth in the non-MET-amplified and MET-low expressing HCC PDX model LI1078. Analysis of The Cancer Genome Atlas (TCGA) data identified four of 164 (2.4%) HCC tumor samples with MET amplification (https://tcga-data.nci.nih.gov/tcga), representing a patient population with potential to derive clinical benefit from AMG 337. Conclusions: These preclinical studies show that the efficacy of AMG 337 in HCC was highly associated with MET amplification. AMG 337 represents a promising, novel clinical therapeutic strategy for targeting HCC with a dependence on the MET pathway. Citation Format: Zhiqiang Du, Sean Caenepeel, Yuqing Shen, Karen Rex, Yanni Zhang, En-Tzu Tang, Ouhong Wang, Wenge Zhong, Hui Zhou, Jacqueline Huang, Eric Huang, Liaoyuan Hu, Angela Coxon, Mingqiang Zhang. Preclinical evaluation of AMG 337, a highly selective small molecule MET inhibitor, in hepatocellular carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5391. doi:10.1158/1538-7445.AM2015-5391

4048 Background: Gastric cancer is a disease with high unmet medical needs in China. MET and its ligand, hepatocyte growth factor, are potential targets in G/GEJ cancer. This study evaluated overal...