EFFECTS OF SARS-COV-2 SPIKE PROTEIN ON THE GROWTH AND PHENOTYPE OF MDA-MB-231 AND MCF-7 BREAST CANCER CELLS AND THEIR SENSITIVITY TO RADIATION-INDUCED APOPTOSIS.

Abstract

Background: The coronavirus infection caused by SARS-Cov-2 virus, in addition to the development of severe acute respiratory syndrome, is responsible for the development of a multiple organ dysfunction syndrome. An important aspect is its relationship with cancer. The data from clinical and experimental studies are contradictory. Thus, further studies are needed to elaborate on the potential effects of SARS-Cov-2 on cancer cells.

Aim: To study the effect of SARS-Cov-2 spike protein (SP) on the survival, phenotype, and sensitivity to radiation-induced apoptosis of breast cancer (BC) cell lines of different molecular subtype (MDA-MB-231 and MCF-7).

Materials and methods: The effects of SARS-Cov-2 SP on MDA-MB-231 and MCF-7 cells were assessed using the cell proliferation assay and flow cytometry (Ki-67, CD44, CD133, CD105, CD90, CD10, CD5, CD19, and p53). The sensitivity to radiationinduced apoptosis was evaluated by 7-amino-actinomycin D and propidium iodide staining.

Results: We did not find any significant short-term effect of SP on the proliferative activity of both studied cell lines. The phenotype of MDA-MB-231 cells cultured with SP changed toward a decrease in CD105+CD90+ and CD105+CD90- subpopulations (p < 0.0001). The p53 expression increased both in SP-treated MDA-MB-231 and MCF-7 cells. The sensitivity of SP-treated MDA-MB-231 and MCF-7 cells to radiation-induced apoptosis, although insignificantly, increased. Apoptosis in irradiated MDA-MB-231 cells was accompanied by a two-fold increase in the fluorescence intensity of p53 in SP-treated MDA-MB-231 cells. In both irradiated cultures, a significant increase in the percent of cells in S-phase after SP treatment was observed compared to SP-untreated cells.

Conclusion: Since most vaccines are based on SP expression, the obtained data might have a certain significance in the study of the effect of anti-SARS-Cov-2 vaccination on tumor growth and the sensitivity of cancer cells to cytoreduction therapies.