Positive Phospho-Focal Adhesion Kinase in Gastric Cancer Associates With Poor Prognosis After Curative Resection

CSE1L in enhancing the effect of defactinib on gastric cancer cells via the inhibition of FAK phosphorylation

Background

Chromosome segregation 1 like (CSE1L) overexpression can promote proliferation and migration in cancer. In previous study, we found that CSE1L expression was higher in gastric cancer (GC) tissues compared to normal tissues. However, the biological function and molecular mechanism of CSE1L in GC remains unclear. In this study, we investigate the function of CSE1L in GC biology and its related molecular mechanisms and therapeutic potentials.

Methods

Transcriptome data from public databases were used to assess CSE1L messenger RNA (mRNA) expression levels in GC. A total of 83 pairs of GC surgical samples were evaluated to determine CSE1L protein expression levels. CSE1L was knocked out in MGC-803 and overexpressed in BGC-823 to evaluate its biological function in GC cells. RNA sequencing (RNA-seq) was used to identify the signaling pathways regulated by CSE1L and the underlying molecular mechanisms, and the transcriptome data were validated. Western blotting and immunofluorescence were used to clarify the regulatory effect of CSE1L on phosphorylated focal adhesion kinase (p-FAK).

Results

CSE1L mRNA was increased in patients with GC, and the high expression of CSE1L was associated with poor prognosis in these patients. Protein levels of CSE1L were also increased in GC surgical samples. CSE1L promoted cell proliferation, cell migration, cell invasion, clone formation, and adhesion ability in GC cells. RNA-seq results suggested that CSE1L upregulated the focal adhesion pathway, which was verified at the mRNA level and protein level. Moreover, CSE1L upregulated p-FAK tyrosine 397 [p-FAK (Y397)] and enhanced the efficacy of defactinib. After the knockout of CSE1L, the killing effect of defactinib on GC cells was intensified.

Conclusions

CSE1L is a potential biomarker for evaluating the prognosis of patients with GC. Knockdown of CSE1L can enhance the efficacy of defactinib by inhibiting p-FAK (Y397), which may be a synergistic target of defactinib.

Diffuse Gastric Cancer: A Comprehensive Review of Molecular Features and Emerging Therapeutics

Diffuse-type gastric cancer (DGC) accounts for approximately one-third of gastric cancer diagnoses but is a more clinically aggressive disease with peritoneal metastases and inferior survival compared with intestinal-type gastric cancer (IGC). The understanding of the pathogenesis of DGC has been relatively limited until recently. Multiomic studies, particularly by The Cancer Genome Atlas, have better characterized gastric adenocarcinoma into molecular subtypes. DGC has unique molecular features, including alterations in CDH1, RHOA, and CLDN18-ARHGAP26 fusions. Preclinical models of DGC characterized by these molecular alterations have generated insight into mechanisms of pathogenesis and signaling pathway abnormalities. The currently approved therapies for treatment of gastric cancer generally provide less clinical benefit in patients with DGC. Based on recent phase II/III clinical trials, there is excitement surrounding Claudin 18.2-based and FGFR2b-directed therapies, which capitalize on unique biomarkers that are enriched in the DGC populations. There are numerous therapies targeting Claudin 18.2 and FGFR2b in various stages of preclinical and clinical development. Additionally, there have been preclinical advancements in exploiting unique therapeutic vulnerabilities in several models of DGC through targeting of the focal adhesion kinase (FAK) and Hippo pathways. These preclinical and clinical advancements represent a promising future for the treatment of DGC.

Focal adhesion kinase as a new player in the biology of onco-hematological diseases: the starting evidence

Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase mainly found in the focal adhesion regions of the plasma membrane and it has a crucial role in migration and the remodeling of cellular morphology. FAK is also linked to several aspects of cancer biology, from cytokine production to angiogenesis, drug resistance, invasion, and metastasis, as well as epithelial-to-mesenchymal transition. The gene locus of FAK is frequently amplified in several human tumors, thus causing FAK overexpression in several cancers. Furthermore, FAK can influence extracellular matrix production and exosome secretion through cancer-associated fibroblasts, thus it has an important role in tumor microenvironment regulation. Although the role of FAK in solid tumors is well known, its importance in onco-hematological diseases remains poorly explored. This review collects studies related to FAK significance in onco-hematological diseases and their microenvironments. Overall, the importance of FAK in blood tumors is increasingly evident, but further research is required to confirm it as a new therapeutic target in hematological contexts.

Identification of Key Genes Associated with Tumor Microenvironment Infiltration and Survival in Gastric Adenocarcinoma via Bioinformatics Analysis

OBJECTIVE

Gastric carcinoma (GC) is the fifth most commonly diagnosed cancer and the third leading cause of cancer-related deaths globally. The tumor microenvironment plays a significant role in the pathogenesis, prognosis, and response to immunotherapy. However, the immune-related molecular mechanisms underlying GC remain elusive. Bioinformatics analysis of the gene expression of GC and paracancerous healthy tissues from the same patient was performed to identify the key genes and signaling pathways, as well as their correlation to the infiltration of the tumor microenvironment (TME) by various immune cells related to GC development.

METHODS

We employed GSE19826, a gene expression profile from the Gene Expression Omnibus (GEO), for our analysis. Functional enrichment analysis of Differentially Expressed Genes (DEGs) was conducted using the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes database.

RESULTS

Cytoscape software facilitated the identification of nine hub DEGs, namely, FN1, COL1A1, COL1A2, THBS2, COL3A1, COL5A1, APOE, SPP1, and BGN. Various network analysis algorithms were applied to determine their high connectivity. Among these hub genes, FN1, COL1A2, THBS2, COL3A1, COL5A1, and BGN were found to be associated with a poor prognosis for GC patients. Subsequent analysis using the TIMER database revealed the infiltration status of the TME concerning the overexpression of these six genes. Specifically, the abovementioned genes demonstrated direct correlations with cancer-associated fibroblasts, M1 and M2 macrophages, myeloid-derived suppressor cells, and activated dendritic cells.

CONCLUSION

Our findings suggest that the identified hub genes, particularly BGN, FN1, COL1A2, THBS2, COL3A1, and COL5A1, play crucial roles in GC prognosis and TME cell infiltration. This comprehensive analysis enhances our understanding of the molecular mechanisms underlying GC development and may contribute to the identification of potential therapeutic targets and prognostic markers for GC patients.

Synergism of FAK and ROS1 inhibitors in the treatment of CDH1-deficient cancers mediated by FAK-YAP signaling

CDH1 deficiency is common in diffuse gastric cancer and triple negative breast cancer patients, both of which still lack effective therapeutics. ROS1 inhibition results in synthetic lethality in CDH1-deficient cancers, but often leads to adaptive resistance. Here, we demonstrate that upregulation of the FAK activity accompanies the emergence of resistance to ROS1 inhibitor therapy in gastric and breast CDH1-deficient cancers. FAK inhibition, either by FAK inhibitors or by knocking down its expression, resulted in higher cytotoxicity potency of the ROS1 inhibitor in CDH1-deficient cancer cell lines. Co-treatment of mice with the FAK inhibitor and ROS1 inhibitors also showed synergistic effects against CDH1-deficient cancers. Mechanistically, ROS1 inhibitors induce the FAK-YAP-TRX signaling, decreasing oxidative stress-related DNA damage and consequently reducing their anti-cancer effects. The FAK inhibitor suppresses the aberrant FAK-YAP-TRX signaling, reinforcing ROS1 inhibitor's cytotoxicity towards cancer cells. These findings support the use of FAK and ROS1 inhibitors as a combination therapeutic strategy in CDH1-deficient triple negative breast cancer and diffuse gastric cancer patients.