Nitidine chloride induces apoptosis in human hepatocellular carcinoma cells through a pathway involving p53, p21, Bax and Bcl-2

Abstract

Nitidine chloride (NC), a novel benzo[c]phenanthridine alkaloid, induces the growth inhibition of cancer cells. Previously it was demonstrated that SMMC-7721 human hepatocellular carcinoma (HCC) cells are highly susceptible to the antiproliferative effects of NC. However, the specific mechanisms remained unclear. In the present study the pathways of growth inhibition induced by NC in SMMC-7721 cells were investigated. The effects of NC on SMMC-7721 cell proliferation were characterized by MTT and colony formation assays. Additionally, BALB/c nude mice were transplanted with SMMC-7721 cells to verify the inhibition of HCC by NC in vivo. The results showed that NC inhibited the proliferation of SMMC-7721 cells in vitro in a time- and dose-dependent manner and identified efficacy in vivo in a mouse model of HCC. Acridine orange (AO) staining, transmission electron microscopy, Annexin V/PI staining, TUNEL assay and caspase-3 activation assays were used to investigate apoptosis and the cell cycle distribution. Inhibition was mediated in part by cell cycle arrest in G2/M, leading to chromatin condensation, DNA fragmentation and the formation of apoptotic bodies. Apoptosis was also verified by Annexin V/PI staining, TUNEL assay and caspase-3 activation. To assess the levels of the cell cycle and apoptotic regulators, immunohistochemical staining, ELISA, real-time PCR and RNA interference (RNAi) were employed. The apoptotic process triggered by NC involved the upregulation of p53, p21 and Bax, and the downregulation of Bcl-2. These data elucidate a pathway of apoptosis in SMMC‑7721 cells that involves G2/M arrest, upregulation of p53, Bax, caspase-3 and p21, and downregulation of Bcl-2.

Nitidine chloride inhibits the malignant behavior of human glioblastoma cells by targeting the PI3K/AKT/mTOR signaling pathway

“…Cytochrome c release and increases in Bax protein levels were observed in the NC-treated GBM cells. These results corroborate previous studies, that NC induces apoptosis in various cancer cells (7,9,20,21,25,26). Apoptosis is thus an additional attribute that may contribute to the efficacy of NC in the treatment of human cancer.…”

“…Therapeutic compounds are desperately needed to improve the dismal survival outcome for glioblastoma multiforme (GBM) patients. Multiple studies have provided compelling evidence that nitidine chloride (NC) plays an anticancer role in various aggressive malignancies (7)(8)(9)(19)(20)(21). In the present study, we demonstrated that NC has anticancer properties affecting many critical cellular processes by targeting the PI3K/Akt/ mTOR pathway in GBM cells.…”

Effects of harmaline on cell growth of human liver cancer through the p53/p21 and Fas/FasL signaling pathways

“…Overexpression of p21 leads to the arrest of cells in G 1 /G 2 or S phase (24). However, cells lacking p21 cannot mediate the effects of p53 upregulation following DNA damage (25). In addition, the consistent expression of p21 and p53 is important in G 2 following DNA injury.…”

PDCD5 regulates cell proliferation, cell cycle progression and apoptosi

“…p53 activates Bax to mediate mitochondrial membrane permeabilization and apoptosis (74), and inhibits Bcl-2 in some conditions such as apoptotic response to DNA damage (75). Activation of p53 signaling pathway, including upregulation of p53, Bax, caspase-3 and downregulation of Bcl-2, was accompanied with G2/M cell cycle arrest in different cell types when treated with different drugs (76)(77)(78). These lines of evidences are in line with our observations in the PDCD5 stably overexpressing A431 cells.…”