Inhibition of osteosarcoma cell proliferation in vitro and tumor growth in vivo in mice model by alstonine through AMPK-activation and PGC-1α/TFAM up-regulation

Abstract

Osteosarcoma, a leading malignant tumor of bones is diagnosed mostly in adolescents and young adults worldwide. The present study investigated alstonine as anti-osteosarcoma agent in vitro as well as in vivo and evaluated the underlying mechanism. Treatment with alstonine led to a significant (P<0.05) reduction in MG63 and U-2OS cell viability. Alstonine treatment of MG63 and U-2OS cells caused a significant reduction in colony formation compared to the control cells. Viability of osteoblasts was not affected by alstonine treatment in 1.25 to 20 µM concentration range. In alstonine treated MG63 and U-2OS cells apoptotic cells increased significantly (P<0.05) compared to the control cells. Moreover, in MG63 and U-2OS cells treatment with alstonine caused a prominent increase in expression of cleaved caspase-9, caspase-3, and PARP. Treatment of MG63 and U-2OS cells with alstonine caused a prominent increase in AMPKα (Thr172) phosphorylation and elevated the count of mtDNA copies compared to the untreated cells. Alstonine treatment of the cells caused a remarkable increase in expression of PGC-1α and TFAM proteins. Treatment of the mice with alstonine at 5 and 10 mg/kg doses for 30 days caused a significant (P<0.05) reduction in xenograft growth. Expression of PGC-1α and TFAM proteins in tumor tissues of the mice treated with alstonine was significantly (P<0.05) raised compared to the control group. Thus, alstonine inhibits osteosarcoma cell growth and activates apoptosis through AMPK dependent pathway. Therefore, alstonine may be considered for treatment of osteosarcoma as it effectively arrests tumor growth in mice.

Defining the most potent osteoinductive culture conditions for MC3T3-E1 cells reveals no implication of oxidative stress or energy metabolism

“…We first examined the gene and/or protein expression levels of Pgc1a and Tfam, as important factors of mitochondrial biogenesis in bone cells [24]. It is known that the AMPK/PGC1α axis is activated during osteoblast differentiation in C3H10T1/2 and Tfam is also up-regulated in osteoblast-like MG63 osteosarcoma cells [55,56]. On the other hand, osteoblast-specific Sod2 deficient mice develop an osteoporotic phenotype [21], while Nox2 increase leads to osteocyte apoptosis [57] and glucocorticoid-induced pre-osteoblast death [58] (41).…”

Defining the Most Potent Osteoinductive Culture Conditions for MC3T3-E1 Cells Reveals No Implication of Oxidative Stress or Energy Metabolism

“…We first examined the gene and/or protein expression levels of Pgc1a and Tfam, important factors of mitochondrial biogenesis in bone cells [24]. It is known that the AMPK/PGC1α axis is activated during osteoblast differentiation in C3H10T1/2, and Tfam is also up-regulated in osteoblast-like MG63 osteosarcoma cells [75,76]. However, we found that Pgc1a was reduced on day 14 compared to day 7 in most of the conditions, suggesting a suppression of mitochondrial activity on a transcriptional level, which was not accompanied by the respective protein levels.…”