Comprehensive analysis of prognostic value and immune infiltration of calpains in pancreatic cancer

Whole-genome Sequencing Analysis of Bile Tract Cancer Reveals Mutation Characteristics and Potential Biomarkers

BACKGROUND/AIM

Bile tract cancer (BTC) is a malignant tumor with a poor prognosis. Recent studies have reported the heterogeneity of the genomic background and gene alterations in BTC, but its genetic heterogeneity and molecular profiles remain poorly understood. Whole-genome sequencing may enable the identification of novel actionable gene mutations involved in BTC carcinogenesis, malignant progression, and treatment resistance.

PATIENTS AND METHODS

We performed whole-genome sequencing of six BTC samples to elucidate its genetic heterogeneity and identify novel actionable gene mutations. Somatic mutations, structural variations, copy number alterations, and their associations with clinical factors were analyzed.

RESULTS

The average number of somatic mutations detected in each case was 53,705, with SNVs accounting for most of these mutations (85.02%). None of the 331 mutations related to BTC in The Cancer Genome Atlas (TCGA) database were found in the mutations identified in our study. A higher prevalence of gene mutations was observed in samples without vascular invasion than in those with vascular invasion. Several genes with differences in mutation accumulation between groups were identified, including ADAMTS7, AHNAK2, and CAPN10.

CONCLUSION

Our study provides novel insights into the genomic landscape of BTC and highlights the potential of whole-genome sequencing analysis to identify actionable gene mutations and understand the molecular mechanisms underlying this malignancy. The high mutational burden, structural variations, and copy number alterations observed in BTC samples in this study underscore the genetic complexity and heterogeneity of this disease.

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.

Structural Polymorphism of Guanine Quadruplex-Containing Regions in Human Promoters

Intramolecular guanine quadruplexes (G4s) are non-canonical nucleic acid structures formed by four guanine (G)-rich tracts that assemble into a core of stacked planar tetrads. G4-forming DNA sequences are enriched in gene promoters and are implicated in the control of gene expression. Most G4-forming DNA contains more G residues than can simultaneously be incorporated into the core resulting in a variety of different possible G4 structures. Although this kind of structural polymorphism is well recognized in the literature, there remain unanswered questions regarding possible connections between G4 polymorphism and biological function. Here we report a detailed bioinformatic survey of G4 polymorphism in human gene promoter regions. Our analysis is based on identifying G4-containing regions (G4CRs), which we define as stretches of DNA in which every residue can form part of a G4. We found that G4CRs with higher degrees of polymorphism are more tightly clustered near transcription sites and tend to contain G4s with shorter loops and bulges. Furthermore, we found that G4CRs with well-characterized biological functions tended to be longer and more polymorphic than genome-wide averages. These results represent new evidence linking G4 polymorphism to biological function and provide new criteria for identifying biologically relevant G4-forming regions from genomic data.