In colon cancer cells fascin1 regulates adherens junction remodeling

Calpain 8 as a potential biomarker regulates the progression of pancreatic cancer via EMT and AKT/ERK pathway

Calpain is a non-lysozyme, calcium-dependent intracellular cysteine protease that has been shown to play a role in tumor proliferation, survival, migration, invasion, and apoptosis. Dysregulation of calpain expression is closely related to tumorigenesis. However, the role of calpain-8 (CAPN8), as a member of the calpain family, in pancreatic cancer (PC) is remains unclear. In elucidating the mechanism of CAPN8 in PC, a comprehensive bioinformatics analysis and in vitro experiments were conducted. The TCGA database was used to explore the expression level of CAPN8, and the results in PC tissues and cell lines were verified. Then, the correlation between CAPN8 and clinicopathological features was analyzed. Additionaly, promoter methylation, immune infiltration, and GO/KEGG enrichment analyses were performed. Lastly, the molecular mechanism of CAPN8 in PC was investigated by using cell counting kit (CCK) 8, transwell, wound healing, Western blot assays, and so on. Results indicate that CAPN8 was highly expressed in PC and correlated with poor prognosis and advanced TNM stage. In addition, a low level of immune infiltration was closely associated with the high expression level of CAPN8. Based on these findings, we hypothesized that CAPN8 is a potential biomarker that regulates progression of PC via EMT and the AKT/ERK pathway. SIGNIFICANCE: Through comprehensive biological information and in vitro experiments, CAPN8 has been confirmed to play an important role in regulating pancreatic cancer (PC) proliferation, migration and invasion. CAPN8 is found to be closely related to the diagnosis, survival and prognosis of PC. Above all, CAPN8 may be a potential biomarker for the diagnosis and prognosis of PC.

Claudin-4 modulates autophagy via SLC1A5/LAT1 as a tolerance mechanism for genomic instability in ovarian cancer

Genome instability is key for tumor heterogeneity and derives from defects in cell division and DNA damage repair. Tumors show tolerance for this characteristic, but its accumulation is regulated somehow to avoid catastrophic chromosomal alterations and cell death. Claudin-4 is upregulated and closely associated with genome instability and worse patient outcome in ovarian cancer. This protein is commonly described as a junctional protein participating in processes such as cell proliferation and DNA repair. However, its biological association with genomic instability is still poorly-understood. Here, we used CRISPRi and a claudin mimic peptide (CMP) to modulate the cladudin-4 expression and its function, respectively in in-vitro (high-grade serous carcinoma cells) and in-vivo (patient-derived xenograft in a humanized-mice model) systems. We found that claudin-4 promotes a protective cellular-mechanism that links cell-cell junctions to genome integrity. Disruption of this axis leads to irregular cellular connections and cell cycle that results in chromosomal alterations, a phenomenon associated with a novel functional link between claudin-4 and SLC1A5/LAT1 in regulating autophagy. Consequently, claudin-4's disruption increased autophagy and associated with engulfment of cytoplasm-localized DNA. Furthermore, the claudin-4/SLC1A5/LAT1 biological axis correlates with decrease ovarian cancer patient survival and targeting claudin-4 in-vivo with CMP resulted in increased niraparib (PARPi) efficacy, correlating with increased tumoral infiltration of T CD8+ lymphocytes. Our results show that the upregulation of claudin-4 enables a mechanism that promotes tolerance to genomic instability and immune evasion in ovarian cancer; thus, suggesting the potential of claudin-4 as a translational target for enhancing ovarian cancer treatment.