RETINOBLASTOMA CELLS OVEREXPRESSING THE MRPS18-2 PROTEIN COULD BE DIFFERENTIATED in vitro

The mitochondrial ribosomal protein MRPS18-2 is involved in cell cycle regulation through its interaction with the retinoblastoma-associated protein, RB. Earlier we have shown that this protein plays an important role in homeostasis of normal and tumor cells, embryogenesis, and in the maintenance of cell stemness. We also found that the MRPS18-2 protein is transactivated by a transcription factor KLF4, one of the Yamanaka factors, inducing cell pluripotency. The aim of the present work was to study the functional consequences of overexpression of the MRPS18-2 and RB proteins in the retinoblastoma cell line (WERI RB 27), concerning putative directed differentiation in vitro. Methods. Direct multipotent differentiation was conducted with cocktails of chemicals for osteogenic, chondrogenic, and adipogenic lineages. Ca+2 ions were stained with Alizarin Red, triglycerides – with Oil Red O, and glycosaminoglycans - with Alcian blue. Results. Parental cells WERI RB-27 did not differentiate upon treatment with any of chemical cocktails, cells remained in suspension and did not change morphology. At the same time, cells that overexpressed MRPS18-2 have demonstrated their differentiation ability into osteo-, chondro-, and adipo-lineages. Conclusions. Thus, we have shown that overexpression of the MRPS18-2 protein in WERI RB 27 cells leads to changes in cell morphology and to ability of the directed multipotent differentiation in vitro. Hence, the MRPS18-2 protein plays a significant role in cancerogenesis and cell stemness.