The Role of cMET in Gastric Cancer—A Review of the Literature

Emerging Therapeutic Targets and Future Directions in Advanced Gastric Cancer: A Comprehensive Review

Metastatic gastric cancer (GC) still represents a critical clinical challenge, with limited treatment options and a poor prognosis. Most patients are diagnosed at advanced stages, limiting the chances of surgery and cure. The identification of molecular targets and the possibility of combining immune checkpoint inhibitors with chemotherapy have recently reshaped the therapeutic landscape of metastatic gastric cancer. The new classification of gastric cancer, mainly based on immunologic and molecular criteria such as programmed cell death 1 (PD-1), microsatellite instability (MSI), and human epidermal growth factor receptor 2 (HER2), has made it possible to identify and differentiate patients who may benefit from immunotherapy, targeted therapy, or chemotherapy alone. All relevant and available molecular and immunological targets in clinical practice for the systemic treatment of this disease are presented. Particular attention is given to possible future approaches, including circulating tumor DNA (ctDNA) for therapeutic monitoring, new targeting agents against molecular pathways such as fibroblast growth factor receptor (FGFR) and MET, chimeric antigen receptor (CAR)-T cells, and cancer vaccines. This review aims to provide a comprehensive understanding of current targets in advanced gastric cancer and to offer valuable insights into future directions of research and clinical practice in this challenging disease.

Better safe than sorry: dual targeting antibodies for cancer immunotherapy

Antibody-based therapies are revolutionizing cancer treatment and experience a steady increase from preclinical and clinical pipelines to market share. While the clinical success of monoclonal antibodies is frequently limited by low response rates, treatment resistance and various other factors, multispecific antibodies open up new prospects by addressing tumor complexity as well as immune response actuation potently improving safety and efficacy. Novel antibody approaches involve simultaneous binding of two antigens on one cell implying increased specificity and reduced tumor escape for dual tumor-associated antigen targeting and enhanced and durable cytotoxic effects for dual immune cell-related antigen targeting. This article reviews antibody and cell-based therapeutics for oncology with intrinsic dual targeting of either tumor cells or immune cells. As revealed in various preclinical studies and clinical trials, dual targeting molecules are promising candidates constituting the next generation of antibody drugs for fighting cancer.

Functional genomics reveals an off-target dependency of drug synergy in gastric cancer therapy

BACKGROUND

Integrating molecular-targeted agents into combination chemotherapy is transformative for enhancing treatment outcomes in cancer. However, realizing the full potential of this approach requires a clear comprehension of the genetic dependencies underlying drug synergy. While the interactions between conventional chemotherapeutics are well-explored, the interplay of molecular-targeted agents with conventional chemotherapeutics remains a frontier in cancer treatment. Hence, we leveraged a powerful functional genomics approach to decode genomic dependencies that drive synergy in molecular-targeted agent/chemotherapeutic combinations in gastric adenocarcinoma, addressing a critical need in gastric cancer therapy.

METHODS

We screened pharmacological interactions between fifteen molecular-targeted agent/conventional chemotherapeutic pairs in gastric adenocarcinoma cells, and examined the genome-scale genetic dependencies of synergy integrating genome-wide CRISPR screening with the shRNA-based signature assay. We validated the synergy in cell death using fluorescence-based and lysis-dependent inference of cell death kinetics assay, and validated the genetic dependencies by single-gene knockout experiments.

RESULTS

Our combination screen identified SN-38/erlotinib as the drug pair with the strongest synergism. Functional genomics assays unveiled a genetic dependency signature of SN-38/erlotinib identical to SN-38. Remarkably, the enhanced cell death with improved kinetics induced by SN-38/erlotinib was attributed to erlotinib's off-target effect, inhibiting ABCG2, rather than its on-target effect on EGFR.

CONCLUSION

In the era of precision medicine, where emphasis on primary drug targets prevails, our research challenges this paradigm by showcasing a robust synergy underpinned by an off-target dependency. Further dissection of the intricate genetic dependencies that underlie synergy can pave the way to developing more effective combination strategies in gastric cancer therapy.

Characterization of MET Alterations in 37 Gastroesophageal Cancer Cell Lines for MET-Targeted Therapy

Capmatinib and savolitinib, selective MET inhibitors, are widely used to treat various MET-positive cancers. In this study, we aimed to determine the effects of these inhibitors on MET-amplified gastric cancer (GC) cells. Methods: After screening 37 GC cell lines, the following cell lines were found to be MET-positive with copy number variation >10: SNU-620, ESO51, MKN-45, SNU-5, and OE33 cell lines. Next, we assessed the cytotoxic response of these cell lines to capmatinib or savolitinib alone using cell counting kit-8 and clonogenic cell survival assays. Western blotting was performed to assess the effects of capmatinib and savolitinib on the MET signaling pathway. Xenograft studies were performed to evaluate the in vivo therapeutic efficacy of savolitinib in MKN-45 cells. Savolitinib and capmatinib exerted anti-proliferative effects on MET-amplified GC cell lines in a dose-dependent manner. Savolitinib inhibited the phosphorylation of MET and downstream signaling pathways, such as the protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) pathways, in MET-amplified GC cells. Additionally, savolitinib significantly decreased the number of colonies formed on the soft agar and exerted dose-dependent anti-tumor effects in an MKN-45 GC cell xenograft model. Furthermore, a combination of trastuzumab and capmatinib exhibited enhanced inhibition of AKT and ERK activation in human epidermal growth factor receptor-2 (HER2)- and MET-positive OE33 cells. Targeting MET with savolitinib and capmatinib efficiently suppressed the growth of MET-amplified GC cells. Moreover, these MET inhibitors exerted synergistic effects with trastuzumab on HER2- and MET-amplified GC cells.

Advances in MET tyrosine kinase inhibitors in gastric cancer

Gastric cancer is among the most frequently occurring cancers and a leading cause of cancer-related deaths globally. Because gastric cancer is highly heterogenous and comprised of different subtypes with distinct molecular and clinical characteristics, the management of gastric cancer calls for better-defined, biomarker-guided, molecular-based treatment strategies. MET is a receptor tyrosine kinase mediating important physiologic processes, such as embryogenesis, tissue regeneration, and wound healing. However, mounting evidence suggests that aberrant MET pathway activation contributes to tumour proliferation and metastasis in multiple cancer types, including gastric cancer, and is associated with poor patient outcomes. As such, MET-targeting therapies are being actively developed and promising progress has been demonstrated, especially with MET tyrosine kinase inhibitors. This review aims to briefly introduce the role of MET alterations in gastric cancer and summarize in detail the current progress of MET tyrosine kinase inhibitors in this disease area with a focus on savolitinib, tepotinib, capmatinib, and crizotinib. Building on current knowledge, this review further discusses existing challenges in MET alterations testing, possible resistance mechanisms to MET inhibitors, and future directions of MET-targeting therapies.

Functional genomics reveals an off-target dependency of drug synergy in gastric cancer therapy

The rational combination of anticancer agents is critical to improving patient outcomes in cancer. Nonetheless, most combination regimens in the clinic result from empirical methodologies disregarding insight into the mechanism of action and missing the opportunity to improve therapy outcomes incrementally. Deciphering the genetic dependencies and vulnerabilities responsible for synergistic interactions is crucial for rationally developing effective anticancer drug combinations. Hence, we screened pairwise pharmacological interactions between molecular-targeted agents and conventional chemotherapeutics and examined the genome-scale genetic dependencies in gastric adenocarcinoma cell models. Since this type of cancer is mainly chemoresistant and incurable, clinical situations demand effective combination strategies. Our pairwise combination screen revealed SN38/erlotinib as the drug pair with the most robust synergism. Genome-wide CRISPR screening and a shRNA-based signature assay indicated that the genetic dependency/vulnerability signature of SN38/erlotinib is the same as SN38 alone. Additional investigation revealed that the enhanced cell death with improved death kinetics caused by the SN38/erlotinib combination is surprisingly due to erlotinib's off-target effect that inhibits ABCG2 but not its on-target effect on EGFR. Our results confirm that a genetic dependency signature different from the single-drug application may not be necessary for the synergistic interaction of molecular-targeted agents with conventional chemotherapeutics in gastric adenocarcinoma. The findings also demonstrated the efficacy of functional genomics approaches in unveiling biologically validated mechanisms of pharmacological interactions.

The Different Roles of MET in the Development and Treatment of Cancer

This Special Issue features contributions from leading international researchers in the field of MET (hepatocyte growth factor (HGF) receptor) biology and therapeutics [...].

Unveiling the role of GAS41 in cancer progression

GAS41, a member of the human YEATS domain family, plays a pivotal role in human cancer development. It serves as a highly promising epigenetic reader, facilitating precise regulation of cell growth and development by recognizing essential histone modifications, including histone acetylation, benzoylation, succinylation, and crotonylation. Functional readouts of these histone modifications often coincide with cancer progression. In addition, GAS41 functions as a novel oncogene, participating in numerous signaling pathways. Here, we summarize the epigenetic functions of GAS41 and its role in the carcinoma progression. Moving forward, elucidating the downstream target oncogenes regulated by GAS41 and the developing small molecule inhibitors based on the distinctive YEATS recognition properties will be pivotal in advancing this research field.