Kashyap, D. | bioRxiv Science

bioRxiv2025

Deciphering Functional Heterogeneity of Cancer-Associated Fibroblasts Across Molecular Subtypes of Breast Cancer

Breast cancer heterogeneity has been well understood based solely on tumor components. However, the tumor microenvironment, which plays a crucial role in cancer by regulating tumor cells differentiation, maturation, and malignant potential, remains under-explored. This study conducted high-throughput RNA-Seq analysis on fresh breast cancer tissues from each molecular subtype and a pure population of cancer-associated fibroblasts (CAFs) isolated from cancer tissue and adjacent normal parts. Based on their functions, we identified three populations of CAFs: a) immune response-related, b) ECM remodeling, and c) calcium/protein binding. Validation of differentially expressed genes among these CAF populations revealed subtype-specific correlations. For instance, CAFs expressing immune response-related genes were significantly enriched in Luminal A/B and TNBC (log +1-fold; p =0.00047), compared to Her-2 positive (log -2.3-fold; p =0.0026). ECM remodeling genes exhibited greater expression in Her-2 positive and TNBC (log +4 to +11-fold; p =7.87E-08) when compared to Luminal subtypes (log +1.5-fold to +6-fold; p =8.66E-05). Calcium binding genes displayed overall similar expression across breast cancer subtypes. Thus, this study identified and underscored the functional heterogeneity of CAFs within the tumor microenvironment across the molecular subtypes of breast cancer.

cancer biology↗

bioRxiv2020

Helicobacter pylori and Epstein-Barr virus coinfection stimulates the aggressiveness in gastric cancer through the regulation of gankyrin

Persistent coinfection of Helicobacter pylori (H. pylori) and Epstein-Barr virus (EBV) promotes aggressive gastric carcinoma. The molecular mechanisms underlying the aggressiveness in H. pylori and EBV coinfected gastric cancer is not well characterized. In the current study, we investigated the molecular mechanism involved in the cooperation of H. pylori and EBV-driven proliferation of gastric epithelial cells. Results showed that the coinfections are significantly more advantageous to the pathogens to create a microenvironment that favors the higher pathogen-associated gene expression. The EBV latent genes EBNA1 and EBNA3C are highly overexpressed in the coinfections compared to individual EBV infection at different time points (12 and 24 hrs). The H. pylori-associated genes 16s rRNA, CagA, and BabA has also been highly overexpressed in coinfections compared to H. pylori alone. Gankyrin is a small protein of 25 KDa involved in multiple biological and physiological processes. The upregulation of gankyrin modulates the various cell signaling pathways, leading to oncogenesis. The gankyrin shows a similar expression pattern as EBNA3C at both transcript and protein levels, suggesting a possible correlation. Further EBV and H. pylori create microenvironments that induce cell transformation and oncogenesis by dysregulation of the cell-cycle regulator, GC marker, cell migration, DNA response, and antiapoptotic genes in infected gastric epithelial cells by enhancing the expression of gankyrin. Our study provides new insights into the molecular mechanism where the interplay between two oncogenic agents (H. pylori and EBV) leads to the enhanced carcinogenic activity of gastric epithelial cells through overexpression of oncoprotein gankyrin. ImportanceIn the present study, we have evaluated the synergistic effect of EBV and H. pylori infection on gastric epithelial cells in various coinfection models. These coinfection models depict the first exposures of gastric epithelial cells with EBV and then the H. pylori. While other coinfection models narrated the first exposures of H. pylori followed by the infection of EBV. This led to an enhanced oncogenic phenotype in gastric epithelial cells. We determined the coinfection of EBV and H. pylori enhanced the expression of oncogenic protein gankyrin. The interplay between EBV and H. pylori promotes the oncogenic properties of AGS cells through the newly discovered oncoprotein gankyrin. EBV and H. pylori mediated upregulation of gankyrin further dysregulates various cancer-associated hallmarks of genes such as cell-migratory, gastric cancer marker, tumor suppressor, DNA damage response, and proapoptotic genes.

microbiology↗