SPIKE PROTEIN OF SARS-COV-2 INCREASES CXCR4 EXPRESSION AND MIGRATION OF BREAST CANCER CELLS IN VITRO.

BACKGROUND There are some data that viral respiratory infections facilitate metastasis of breast cancer (BC). However, whether the coronavirus SARS-CoV-2 is a trigger for BC progression is not yet clear, as well as the possible mechanisms of its involvement. AIM The work aimed to study the effect of the SARS-Cov-2 spike protein (SP) on the expression profile of components of the CXCL12/CXCR4 key signaling аxis of BC, cell adhesion markers CD326, CD54, epithelial cells cytokeratin-18 and b-catenin, and migratory activity in in vitro model system. MATERIALS AND METHODS The expression profile of the studied markers was detected by flow cytometry after 48 h of incubation of MCF-7 and MDA-MB-231 cells with SP. Marker expression was assessed by the number of positive cells (%) and the level of its expression (the relative index of mean fluorescence intensity of cells, iMFI). Cell migration was analyzed by the scratch assay. RESULTS After SP treatment, a significant increase in CXCR4 expression was detected in the cytoplasm of both MCF-7 and MDA-MB-231 cells. SP caused opposite effects on CXCL12 expression - an increase in the MDA-MB-231 cells and decrease in the MCF-7 cells. In addition, in MCF-7 cells, SP treatment resulted in a decrease in the number of CD54-positive cells, the iMFI of CD326, cytokeratin-18, and a slight increase in the iMFI of b-catenin, while in the MDA-MB-231 cell line, a significant decrease in the iMFI of CD54 was observed. SP accelerated the migration activity of MDA-MB-231 and MCF-7 cells, the effect being more pronounced in MDA-MB-231 cells. CONCLUSION The immunophenotypic changes in the expression profile of several markers under the influence of SP may indicate the induction of the epithelial-mesenchymal transition in the MCF-7 cells and increased migration activity in both cell lines.