p38α MAPK-mediated induction and interaction of FOXO3a and p53 contribute to the inhibited-growth and induced-apoptosis of human lung adenocarcinoma cells by berberine

Abstract

BackgroundBerberine (BBR), a component from traditional Chinese medicine, has been shown to possess anti-tumor activity against a wide spectrum of cancer cells including human lung cancer, but the detailed mechanism underlining this has not been well elucidated.MethodsIn this study, the effect of berberine on cell growth and apoptosis were assessed by MTT, flow cytometry and Hoechst 33258 staining assays. The phosphorylation of p38 MAPK and ERK1/2, and expressions of p38 MAPK isoforms α and β, total ERK1/2, p53, FOXO3a and p21 protein were evaluated by Western Blot analysis. Silencing of p38 MAPK isoform α and β, p53, FOXO3a and p21 were performed by siRNA methods. Exogenous expression of FOXO3a was carried out by electroporated transfection assays.ResultsWe showed that BBR significantly inhibited growth and induced cell cycle arrest of non small cell lung cancer (NSCLC) cells in the G0/G1 phase in a dose-dependent manner. Furthermore, we found that BBR increased phosphorylation of p38 MAPK and ERK1/2 in a time-dependent and induced protein expression of tumor suppressor p53 and transcription factor FOXO3a in a dose-dependent fashion. The specific inhibitor of p38 MAPK (SB203580), and silencing of p38α MAPK by small interfering RNAs (siRNAs), but not ERK1/2 inhibitor (PD98059) blocked the stimulatory effects of BBR on protein expression of p53 and FOXO3a. Interestingly, inhibition of p53 using one specific inhibitor (Pifithrin-α) and silencing of p53 using siRNAs overcome the inhibitory effect of BBR on cell growth. Silencing of FOXO3a appeared to attenuate the effect of BBR on p53 expression, cell proliferation and apoptosis. Furthermore, BBR induces the protein expression of cell cycle inhibitor p21 (CIP1/WAF1), which was not observed in cells silencing of p53 or FOXO3α gene. Intriguingly, exogenous expression of FOXO3a enhanced the expression of p21 (CIP1/WAF1) and strengthened BBR-induced apoptosis.ConclusionOur results show that BBR inhibits proliferation and induces apoptosis of NSCLC cells through activation of p38α MAPK signaling pathway, followed by induction of the protein expression of p53 and FOXO3a. The latter contribute to the BBR-increased p21 (CIP1/WAF1) protein expression. The exogenous FOXO3a, interaction and mutually exclusive events of p53 and FOXO3a augment the overall response of BBR.

Emodin Increases Expression of Insulin-Like Growth Factor Binding Protein 1 through Activation of MEK/ERK/AMPKα and Interaction of PPARγ and Sp1 in Lung Cancer

“…Cell viability was measured using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay as reported previously [25]. In brief, NSCLC cells were counted and seeded into a 96-well microtiterplate.…”

“…The detailed procedure was reported previously [25]. Briefly, equal amounts of protein from whole cell lysates were separated on SDS polyacrylamide gels.…”

“…The detailed procedure was reported previously [25]. For the transfection procedure, cells were seeded in 6-well or 96-well culture plates in RPMI 1640 medium containing 10% FBS (no antibodies), grown to 60% confluence, and PPARγ, IGFBP1 and control siRNAs purchased from Life Technologies (Carlsbad, CA, USA), were transfected using Lipofectamine 3000 Transfection Reagent.…”

A map describing the association between effective components of traditional Chinese medicine and signaling pathways in cancer cells in vitro and in vivo

“…In vivo, it also inhibits mTOR and activates caspase-3 cleavage (13). In A549 (human lung adenocarcinoma cell line), berberine inhibits proliferation and induces apoptosis of adenocarcinoma cells by activating the p38α MAPK signaling pathway followed by inducing p53 and FOXO3α (14).…”

Mitogen-activated protein kinase signaling pathway in oral cancer (Review)

“…Among these is the mitogen activated protein kinase (MAPK) signaling pathway, which regulates the expression of a large number of proteins involved in the control of cell proliferation, differentiation and apoptosis (6,7), and remains a focus of investigation for therapeutic targeting, along with the development of appropriate inhibitors (8). These inhibitors have been demonstrated to be effective for the treatment of oral cancer and other malignancies, including human colon cancer, breast cancer and lung cancer (9)(10)(11)(12). Certain inhibitors, which have been examined in various clinical trials, are being used to treat patients with oral cancer and are eliciting promising results.…”