Abstract
Betulin (BT) has been identified to exhibit potential benefits for treating hepatocellular carcinoma (HCC). The results of the present study demonstrated that a new semisynthetic derivative of BT, 3,28-di-(2-nitroxy-acetyl)-oxy-BT, may effectively decrease the viability of Huh7 cells. Mechanistic studies revealed that 3,28-di-(2-nitroxy-acetyl)-oxy-BT inhibited the transition between G2 and M phase of the cell cycle by regulating cell cycle regulatory proteins. Additional study revealed that 3,28-di-(2-nitroxy-acetyl)-oxy-BT may trigger Huh7 cells to undergo caspase-dependent apoptosis as an increased proportion of cells were identified in the sub-G1 phase, which may be a result of poly(ADP-ribose) polymerase cleavage and caspase activation. Furthermore, 3,28-di-(2-nitroxy-acetyl)-oxy-BT-induced apoptosis was mitochondrion-mediated. The results of the present study demonstrated that Bcl-2-associated X protein translocated to the mitochondria from the cytosol following 3,28-di-(2-nitroxy-acetyl)-oxy-BT treatment. Notably, the phosphoinositide 3-kinase/protein kinase B signaling pathway was involved in 3,28-di-(2-nitroxy-acetyl)-oxy-BT-treated Huh7 cells. Therefore, the results of the present study demonstrated that 3,28-di-(2-nitroxy-acetyl)-oxy-BT may inhibit HCC, which may be a possible application to treat HCC.