Apoptosis-Inducing Factor (AIF) content in tumor cell mitochondria from colorectal cancer patients

Purpose of the study . To investigate the level of protein AIF in the mitochondria of tumor cells and visually unchanged tissues of the colon in male and female patients with colorectal cancer. Materials and methods. The study included results, obtained from 132 patients with stage T2–3N0M0 colon cancer, comprising 52 women and 80 men. Mitochondria were isolated from human colon and tumor tissue cells using differential centrifugation in a high-speed refrigerated centrifuge. The concentration of protein AIF (pg/mg protein) in mitochondria was determined using ELISA «Human AIF Elisa Kit» (Cloud-CloneCorp., China). Results. It was established that in males, the AIF level in the mitochondria of rectal, sigmoid colon and ascending colon tumor cells was 2.4 times, 1.9 times ( p < 0.05) and 3.1 times higher, respectively, than in the mitochondria of the corresponding tissues not affected by the tumor. In the mitochondria of the intestinal tissue not affected by the tumor, significant differences in the AIF content were observed, with levels varying depending on the anatomical location. In the sigmoid colon, the level of this factor was found to be 1.9 ( p < 0.05) and 2.6 times higher than in the rectum and ascending colon, respectively. Concurrently, no notable discrepancies in the AIF concentration within the mitochondria of conditionally unimpaired tissues were observed in the female subjects. The AIF content was found to be higher in the mitochondria of tumor cells in women than in conditionally intact tissues. Specifically, it was observed to be 2.1 times higher in rectal tumors, 4.4 times higher in sigmoid colon tumors and 1.7 times ( p < 0.05) higher in ascending colon tumors. Significant discrepancies in the AIF content between men and women, as well as between the mitochondria of tumor sample cells, were identified. In the rectal and ascending colon tumor, the AIF level in women was found to be markedly elevated in comparison to men, exhibiting a ratio of 1.3 ( p < 0.05) and 2.4, respectively. Conclusion. In patients with colorectal cancer, the content of AIF in tumor mitochondria is observed to increase. This can be considered to represent stimulation mechanism of tumor proliferative activity due to its NADH/NADPH oxidase function, which promotes the survival of malignant cells.