Matrix metalloproteinases and heat shock proteins on extracellular vesicles in colorectal cancer patients: association with metabolic status

Introduction. In most patients with colorectal cancer (CRC), the tumor develops against the background of metabolically healthy obesity or metabolic syndrome (more than 60 % of patients), the key pathogenetic moment of which is developing hyperinsulinemia. Metabolic changes are also characteristic of patients with colon polyps (CP), which are currently considered as the most significant precancerous diseases. It has been shown that fractions of small extracellular vesicles (EVs) of adipocyte origin are specifically enriched in extracellular matrix proteins, including matrix metalloproteinases (MMPs), chaperones, and some metabolic enzymes involved in the synthesis of lipids and carbohydrates. This was the reason for choosing exosomal markers in our study. Comparison of protein expression on CD9- and FABP-4 positive vesicles will be useful to explain some clinical issues, such as the effectiveness of thermoradiotherapy or radiotherapy in obese CRC patients; for a more substantiated search for vesicular prognostic markers in obese cancer patients. However, taking into account the lack of data in the literature on the level of MMPs and HSPs expression in the composition of the total pool of EVs and in the composition of FABP4-positive EVs in patients with PTC and CRC patients, the aim of the work was formulated.

Aim. Study of the level of MMPs and heat shock proteins (HSPs) on CD9- and FABP4-positive EVs in patients with CP and CRC in relation to metabolic status.

Materials and methods. The study included 12 patients with CRC (T2-4N0-2M0; mean age 59.6 ± 1.6 years) who were treated at the Department of Abdominal Oncology of the Cancer Research Institute of the Tomsk National Research Medical Center from 2019 to 2021. The comparison group included 10 patients with CP. The level of proteins on the surface of CD9- and FABP4-positive EVs was studied using flow cytometry.

Results. MMP9-positive EVs were detected more often in CRC patients than in CP patients, however, MMP9+MMP2+TIMP-positive EVs were significantly more frequently detected in CP patients. Among the studied heat shock proteins, HSP60 was most often expressed on the surface of EVs, and HSP60-positive EVs were detected on the surface of CD9-positive exosomes in patients with PTC much more often than in CRC. In patients with CRC, compared with patients with СP, among FABP4-positive EVs, the proportion of triple-positive EVs and EVs with the MMP9+MMP2-TIMP1+ phenotype significantly increases, which in general may indicate overexpression of MMP9 and TIMP1 by adipocytes or marcrophages of adipose tissue in patients with CRC. Correlation analysis revealed multiple correlations of individual phenotypes of CD9-positive EVs in patients with CRC with body mass index and serum high density lipoprotein cholesterol levels, while the phenotypes of FABP4-positive EVs were associated mainly with triglyceride levels.

Conclusions. The phenotypes of CD9-positive and FABP4-positive circulating EVs are promising as predictors for clarifying cancer risk in patients with colon polyps, as well as in terms of explaining the effectiveness of the treatment of CRC patients with obesity or metabolic syndrome.