Kang-Ai Injection Inhibits Gastric Cancer Cells Proliferation through IL-6/STAT3 Pathway / 中国结合医学杂志

OBJECTIVE@#To explore the mechanisms underlying the proliferative inhibition of Chinese herbal medicine Kang-Ai injection (KAI) in gastric cancer cells.@*METHODS@#Gastric cancer cell lines MGC803 and BGC823 were treated by 0, 0.3%, 1%, 3% and 10% KAI for 24, 48 and 72 h, respectively. The cell proliferation was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The apoptosis and cell cycle were evaluated by flow cytometry. Interleukin (IL)-6 mRNA and protein expression levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immune sorbent assay (ELISA), respectively. The protein expression levels of cyclin A, cyclin E, cyclin B1, cyclin D1, p21, retinoblastoma (RB), protein kinase B (AKT), extracellular regulated protein kinases (ERK), signal transducer and activator of transcription (STAT) 1 and STAT3 were detected by Western blot.@*RESULTS@#KAI inhibited the proliferation of MGC803 and BGC823 gastric cancer cells in dose- and time-dependent manner. After treated with KAI for 48 h, the proportion of G1 phase was increased, expression level of cyclin D1 and phosphorylation-RB were down-regulated, whereas the expression of p21 was up-regulated (all P<0.01). Furthermore, 48-h treatment with KAI decreased the phosphorylation level of STAT3, inhibited the mRNA and protein expressions of IL-6 (all P<0.01). IL-6 at dose of 10 ng/mL significantly attenuated the proliferative effect of both 3% and 10% KAI, and recovered KAI-inhibited STAT3 phosphorylation and cyclin D1 expression level (all P<0.01).@*CONCLUSION@#KAI exerted an anti-proliferative function by inhibiting IL-6/STAT3 signaling pathway followed by the induction of G1 phase arrest in gastric cancer cells.

Effect of bufalin-inducing apoptosis on Bcl-2 and PKC in HL-60 cells / 中国实验血液学杂志

Previous study revealed that bufalin can inhibit proliferation, and induce apoptosis in some human cancer cell lines. However, the mechanism of its anticancer effect has not been fully understood. The present study was designed to investigate the effects of bufalin-induced apoptosis on Bcl-2 and PKC in human leukemic HL-60 cells. The cell viability was determined by trypan blue dye exclusion. The apoptosis was detected by morphology, flow cytometry and DNA agarose gel electrophoresis. The expressions of Bcl-2 and PKC were analyzed by Western blot, and activity of PKC was assayed by [gamma-(32)P] isotope incorporation method. The results showed as follows: (1) proliferation of HL-60 cells was inhibited by bufalin and the IC(50) at 24, 48, 72 hours were (25.8 +/- 2.1), (8.0 +/- 1.2) and (2.3 +/- 0.3) nmol/L, respectively. (2) apoptosis of HL-60 cells was induced when the cells were treated with bufalin at concentration of 50 nmol/L for 24 hours. (3) compared with control, treatment with bufalin at concentration of 50 nmol/L for 6 - 24 hours resulted in downregulation of protein expression, decrease of phosphorylation, and cleavage of Bcl-2, simultaneously. (4) the activity of total PKC was unchanged when HL-60 cells were exposed to 1 - 100 nmol/L bufalin for 30 minutes, but PKCbetaII underwent translocation from cytosol to membrane. It is concluded that apoptosis induced by bufalin is associated with downregulation of protein expression, dephosphorylation, and cleavage of Bcl-2 in HL-60 cells.