Heterogeneous collagen-containing composition: effect on HeLa cervical cancer cells and assessment of prospects for use in oncological practice

Abstract

Understanding the effects on tumor cells underlies possible practical use of collagen- containing composition (HCCC) for the treatment of radiation therapy related complications. Purpose of the study. Is to investigate the effects of heterogeneous HCCC on growth, viability, proliferative activity and stem cell pool of cervical cancer in vitro. Materials and methods. HeLa cells were incubated with commercially available HССC (trademark Sphero®GEL in two versions: Medium and Light) for 24–72 h. We determined the total number of tumor cells, their viability by MTT assay, the total proportion of cells in S + G2 + M phases by flow cytometry, as well as the relative and absolute number of cancer stem cells (CSCs) identified by the ability to remove the fluorescent dye Hoechst 33342 from cells (SP method) and CD133 expression, after incubation with HCCC in two dilutions and in control samples. Results. When using HCCC–Medium in a dilution of 1/5 (the lowest of the studied dilutions), decrease in the total number of tumor cells by 13 % from the control level was recorded during the entire observation period (p < 0.05). This effect was accompanied by parallel decrease in cell viability and decrease in proliferative activity in the first time after the onset of exposure compared to control (p < 0.05). The tendency towards decreases in the absolute number of CSCs, which were independently detected by SP and CD133 immunophenotyping methods after 72-hour incubation with HCCC–Medium 1/5, was observed. The number of SP and CD133+ cells decreased by 1.3 times compared to control. Similar, but short-term or less pronounced effects were shown for HCCC–Medium in a higher dilution of 1/20 and HCCC–Light in all dilutions in relation to the total number of tumor cells and the size of CSC pool. Conclusion. The obtained results prove the absence of stimulating effect of HCCC–Medium and HCCC–Light on both the total mass of HeLa tumor cells and the CSC subpopulation in vitro and show the prospects for further preclinical and clinical studies on the use of HCCC in rehabilitation programs for treatment of atrophic and/or radiation vaginitis of varying severity in cancer patients.