Effects of Pinus massoniana bark extract on the size of HeLa cells via Nesprin-2 pathway

Proanthocyanidins (PAs) is the main constituent of Pinus massoniana bark extract (PMBE). PMBE was reported to induce cell cycle arrest and apoptosis in HeLa cells. During cell division, cells synthesize protein in G1 and G2 phases and replicate chromatin in S phase during interphase, which increases cell mass. Nesprins, a kind of protein encoded by syne gene, is a vital part of cytoskeleton and plays a role in cell cycle progress and cell division. HeLa cells were used as a model to examine effects of PMBE on cell growth and Nesprins expression with MTT assay and RT- PCR analysis, respectively. The cell size was evaluated by counting the cell number in a fixed area under microscope. The results showed that the size of survival HeLa cells in PMBE-treated group was obviously larger than that of those in control group (p = 0.00223, < 0.01), whilethe mRNA expression level of Nesprin-2 decreased significantly in PMBE-treated group (p = 0.0201, < 0.05). On this account, we put forward a hypothesis that PMBE inhibits the expression of syne-2, which leads to the decrease of Nesprin-2 and further results in the size increase of HeLa cells.