Effect of Rapamycin on Nucleostemin Expression in Osteosarcoma MG63 Cells

Objective To investigate the regulation and possible mechanisms of rapamycin (RAPA) on nucleostemin (NS) expression in osteosarcoma MG63 cells. Methods After treatment with RAPA or in combination with various kinase inhibitors pre-treatment, the mRNA and protein expression of NS were determined by reverse transcription polymerase chine reaction (RT-PCR) and Western blot respectively. Effect of RAPA on the selected kinase was analysed by Western blot. Results RAPA up-regulated NS mRNA and protein expression and the protein kinase B (Akt) inhibitor prevented the effects of RAPA. RAPA did not affect the total Akt activity. However, the nuclear translocation of phosphorylated Akt at Ser473 (pAkt) was enhanced by RAPA. Conclusion RAPA possibly increases the expression of NS in MG63 cells through enhancing the nuclear translocation of pAkt.