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The aim of this study was to investigate the antitumor effect of zoledronic acid (ZOL) in the NB4 human acute promyelocytic leukemia (APL) cell line and explore the potential mechanism of action of this compound. NB4 cells were exposed to various concentrations (0-200μM) of ZOL. Cell viability was measured by MTS assay. The extent of cell apoptosis and distribution of cells in the different phases of the cell cycle were analyzed with flow cytometry. The expression of apoptosis- and cell cycle-related proteins was assayed by Western blot. The combined effect of ZOL and arsenic trioxide (ATO) on the proliferation of NB4 cells was also determined. The results of this study indicate that ZOL inhibits cell proliferation in a time- and dose-dependent fashion and also induces apoptosis and S phase arrest in a dose-dependent manner. The Western blot analysis confirmed the induction of apoptosis and S phase arrest, revealing that the pro-apoptosis proteins Bax, Puma and activated caspase-9 were upregulated and the anti-apoptosis proteins Bcl-2 and Bcl-xL were downregulated. ZOL at a concentration of 50μM synergized with 0.5μM ATO on the growth inhibition of NB4 cells. Taken together, our data indicate that ZOL exerts a potent antitumor effect on NB4 cells by inducing apoptosis and cell cycle arrest, and that ZOL can synergize with the traditional chemotherapy drug ATO., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Aim: To investigate the influence of peroxisome proliferator-activated receptor gamma (PPARgamma) ligand, 15-deoxy-12, 14-prostaglandin J2 (15dPGJ2) on the proliferation and apoptosis of MCG-803 human gastric cancer cell lines., Methods: Cell proliferation was measured by 3H-TdR assay. Apoptosis was determined by ELISA and TUNEL staining. Protein and mRNA level of bcl-2 family and COXs were measured by Western blotting and Northern blotting respectively. PGE2 production was examined by RIA., Results: 15dPGJ2 inhibited cell growth and induced apoptosis of MCG-803 cells. The COX-2 and bcl-2/bax ratios were decreased following 15dPGJ2 treatment. The PGE2 production in supernatants was also decreased. These changes were in a dose-dependent manner., Conclusion: 15dPGJ2 may be a useful therapeutic agent for the treatment of gastric cancer.

Aim: To illustrate the possible role of cell differential agent-II (CDA-II) in the apoptosis of hepatoma cells induced by arsenic trioxide (As(2)O(3))., Methods: Hepatoma cell lines BEL-7402 and HepG2 were treated with As(2)O(3) together with CDA-II. Cell surviving fraction was determined by MTT assay; morphological changes were observed by immunofluorescence staining of Hoechst 33,258; and cell cycle and the apoptosis index were determined by flow cytometry (FCM)., Results: Cytotoxicity of CDA-II was low. Nevertheless, CDA-II could strongly potentiate arsenic trioxide-induced apoptosis. At 1.0 g/L CDA-II, IC(50) of As(2)O(3) in hepatoma cell lines was reduced from 5.0 micromol/L to 1.0 micromol/L (P<0.01). The potentiation of apoptosis was dependent on the dosage of CDA-II. FCM indicated that in hepatoma, cell growth was inhibited by CDA-II at lower concentrations (<2.0 g/L) primarily by arresting at S and G(2) phase, and at higher concentrations (>2.0 g/L) apoptotic cell and cell cycle arresting at G(1) phase increased proportionally. The combination of two drugs led to much higher apoptotic rates, as compared with the either drug used alone., Conclusion: CDA-II can strongly potentiate As(2)O(3)-induced apoptosis in hepatoma cells, and two drugs can produce a significant synergic effect.

Tetrandrine (Tet), a bisbenzylisoquinoline alkaloid, has been reported to possess anti-tumour activity. However, its effects on human glioma remain unknown. In this study, we demonstrated that Tet inhibited human glioma cell growth in vitro and in vivo . It has been hypothesised that Tet inhibits glioma growth by affecting glioma cell survival, proliferation and vasculature in and around the xenograft tumour in the chick CAM model and signal transducer and activator of transcription 3 (STAT3) mediated these activities. Therefore, we conducted a detailed analysis of the inhibitory effects of Tet on cell survival using a TUNEL assay and flow cytometric analysis; on cell proliferation based on the expression of proliferating cell nuclear antigen; and on angiogenesis using a CAM anti-angiogenesis assay. We used western blotting to investigate the role of STAT3 on the anti-glioma activities of Tet. The results revealed that Tet inhibited survival and proliferation in human glioma cells, impaired tumour angiogenesis and decreased the expression of phosphorylated STAT3 and its downstream proteins. In sum, our data indicate that STAT3 is involved in Tet-induced the regression of glioma growth by activating tumour cell apoptosis, inhibiting glioma cell proliferation and inhibiting angiogenesis. [ABSTRACT FROM AUTHOR]