Evaluation of the citotoxic and molecular response of the cultural filtrates and proteins of various bacteria isolates on human fibroblast cells

Colorectal cancer is a type of cancer that begins with the formation of polyps in epithelial cells of the colon and rectum. Polyps formed are considered as precursors for many colorectal cancers. Colorectal cancer is the third cause of death in women after lung and breast cancer, fourth in men, after lung and prostate cancer. The possible risk factors for the disease have been investigated, but the relationship between colorectal cancer pathogenesis and microorganisms has not been fully elucidated. Therefore, in our study, bacterial isolation was made from cancerous tissues of patients with colorectal cancer. Bacterial culture filtrates and total proteins were isolated and their effects on healthy fibroblast cell line were determined by WST-8, hemolysis test, Caspase-3, JC-1 and Annexin- V analysis methods; changes in gene level were analyzed by qRT-PCR method. As a result of isolation, 3 Klebsiella pneumoniae, 1 Escherichia coli and 1 Acinetobacter baumannii were isolated from biopsy samples. As a result of the analysis, it was concluded that culture filtrate and proteins of microorganisms lead to death of healthy cells especially inflammation and necrosis. When the effects on gene level were examined, it was observed that they caused a decrease in expression of tumor suppressor genes such as TP53, SMAD and APC and an increase in expression of KRAS oncogene compared to control. It is believed that the findings of this study will contribute to the development of microorganism-based treatment approaches for the treatment of colorectal cancer.