Mitochondrial size as a potential factor in colorectal cancer metastasis.

Abstract

e15546 Background: The accelerated progression of colorectal cancer, with frequent recurrences and distant metastases, highlights the need for targeted attention to endogenous structures such as mitochondria. Their ability to actively translocate within environments and tissues is combined with powerful signaling regulation of structural and metabolic processes during tumor growth. Modern technologies make it possible to determine some physical characteristics of mitochondria to understand their role in metastasis processes. The aim of the study was to investigate the perimeter size of mitochondria isolated from rectal adenocarcinoma tissue and conditionally healthy tissue along the tumor resection line in patients of both sexes, depending on the presence or absence of metastases. Methods: Samples were obtained from 44 patients (median age: 66 years; range: 58–73) who underwent surgery for stage T2-3N0M0, G2-grade rectal adenocarcinoma. Tumor fragments and intestinal tissue from the resection margin were fixed in a formaldehyde/glutaraldehyde solution. Standard tissue processing methods were used, and ultrathin sections were examined using a Jeol JEM-1011 transmission electron microscope (TEM). Mitochondrial perimeter was measured on electron micrographs using FiJi software. Statistical analysis of the results was performed using the Statistica 10.0 software package. Results: A comprehensive ultrastructural study and statistical analysis of the perimeter size of mitochondria isolated from rectal adenocarcinoma in patients of both sexes was conducted. The results indicated that there were no statistically significant intergroup differences in mitochondrial size, categorized as conditionally small (0-1 μm), medium (1-2 μm) and large ( > 2 μm), depending on the presence or absence of metastases. In contrast to the tumor, in conditionally healthy tissue along the rectal resection line, the proportion of mitochondria with a perimeter of ˃2 μm, which were characterized by the most pronounced signs of dysfunction, increased by 3.6 times in women and 4.8 times in men with metastases compared to the indicators in all patients without metastases (p < 0.05). Conclusions: The significance of differences in the perimeter indices of mitochondria isolated from conditionally healthy tissue at the resection line of rectal adenocarcinoma, regardless of the gender differences of patients, indicated the possibility of a morphofunctional relationship between processes occurring at the ultrastructural mitochondrial level and the metastasis of rectal cancer. Translocation of mitochondria from rectal adenocarcinoma into layers of conditionally healthy submucosal tissue at the level of the tumor resection line indicates the dangerous potential of the motor and regulatory activity of mitochondria of malignant neoplasms in tumor progression.