The role of SWI/SNF complexes in digestive system neoplasms.

Chromatin remodeling is a critical step in the DNA damage response, and the ATP-dependent chromatin remodelers are a group of epigenetic regulators that alter nucleosome assembly and regulate transcription factor accessibility to DNA, preventing genomic instability and tumorigenesis caused by DNA damage. The SWI/SNF chromatin remodeling complex is one of them, and mutations in the gene encoding the SWI/SNF subunit are frequently found in digestive tumors. We review the most recent literature on the role of SWI/SNF complexes in digestive tumorigenesis, with different SWI/SNF subunits playing different roles. They regulate the biological behavior of tumor cells, participate in multiple signaling pathways, interact with multiple genes, and have some correlation with the prognosis of patients. Their carcinogenic properties may help discover new therapeutic targets. Understanding the mutations and defects of SWI/SNF complexes, as well as the underlying functional mechanisms, may lead to new strategies for treating the digestive system by targeting relevant genes or modulating the tumor microenvironment.

Exosomal microRNAs mediating crosstalk between cancer cells and cancer-associated fibroblasts in the tumor microenvironment.

PURPOSE: Cancer-associated fibroblasts (CAFs) play an important role in tumor formation and development by serving as the most influential stromal cells within the tumor microenvironment (TME). The communication between tumor cells and CAFs, along with the resulting impact, is more important than originally anticipated. Numerous studies have demonstrated that microRNAs (miRNAs) play an essential role in this crosstalk, and related evidence continues to emerge and advance. In addition, exosomes containing miRNAs have been found as a crucial mode of interaction between these two types of cells, with a more direct and precise role. Under the influence of exosomal miRNAs, normal fibroblasts are converted into CAFs. By doing so, CAFs can greatly promote tumor progression. Additionally, through exosomal miRNAs, activated CAFs may alter the genetic expression in tumor cells, affecting the TME and promoting malignant biological processes. Learning more about exosomal miRNAs in tumor cells and CAFs, and the intricate molecular networks that link CAFs to cancer cells, may help researchers develop more sensitive and effective cancer treatments targeting miRNAs, exosomes and CAFs, thereby giving hope to cancer patients. METHODS: A comprehensive search of the literature was conducted through PubMed databases. The keywords entered for the search included: exosomes, cancer-associated fibroblasts, microRNA and cancer. This search provided information about articles published in peer-reviewed journals until 2022. Information from these articles was collected and analyzed in this review. RESULTS: Exosomal miRNAs can act as tumor inhibitors or tumor inducers by affecting several targets and molecular signaling pathways. MiRNAs and exosomes involved in crosstalk could have promising applications in cancer diagnosis, prognosis, and therapy. CONCLUSION: This finding about the crosstalk can help find and develop innovative miRNA-based approaches towards diagnosis, prognosis, and anti-cancer treatments.