Induction of G2/M Arrest by Berberine via Activation of PI3K/Akt and p38 in Human Chondrosarcoma Cell Line

Berberine is a clinically important natural isoquinoline alkaloid found in many medicinal herbs. Berberine has been shown to have many pharmacological effects including antimicrobial, antitumor, and anti-inflammatory activities. However, the effects and mechanism of action of berberine have not been studied in chondrosarcoma. Therefore, the effects of berberine on proliferation in a human chondrosarcoma cell line (HTB-94) were investigated. Berberine inhibited cell proliferation in a concentration-dependent manner. We also determined that inhibition of cell proliferation by berberine occurred via G(2)/M phase arrest in HTB-94 cells. Berberine induced cell cycle arrest at the G(2)/M phase by upregulation of p53 and p21 expression and suppressed cyclin B1, cyclin-dependent kinase 1 (cdc2), cdc25c, and phosphorylated retinoblastoma tumor-suppressor protein (pRb) expression. In addition, berberine stimulated phosphorylation of protein kinase B (Akt) and p38 kinase. Inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt with LY294002 (LY) and p38 kinase with SB203580 (SB), respectively, decreased berberine-induced p53 and p21 expression and restored cell proliferation and expression of cyclin B1, cdc2, cdc25c, and pRb cell cycle progression proteins. These results suggest that berberine-induced inhibition of cell proliferation by cell cycle arrest at the G(2)/M phases was regulated through PI3K/Akt and p38 kinase pathways in HTB-94 chondrosarcoma cells.