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@# Objective: To investigate the effects and the underlying mechanisms of betulinic acid (BEA) on sensitizing pancreatic cancer cell lines Panc-1 and Miapaca-2 to gefitinib. Methods: After the cell culture was completed, Panc-1 and Miapaca-2 cells were randomly divided into 4 groups: control group (without treatment), BEAgroup, gefitinib group and BEAcombined with gefitinib group, respectively.The sensitization effect of BEAon gefitinib-insensitive pancreatic cancer cells was detected by MTS assay. The treatment effects of combined treatment of gefitinib and BEA against Panc-1 and Miapaca-2 cells were evaluated by colony formation assay. Flow cytometry was used to examine the effect of BEAon apoptosis of Panc-1 cells while WB was applied to determine the effect of BEAonapoptosis-related proteins. Surface plasmon resonance (SPR) experiment was used to detect the direct combination between signal transducer and activator of transcription 3(STAT3) and BEA; Molecular docking and molecular dynamics simulation experiments were adopted topredict the combining mode between STAT3 and BEA. Results: BEA synergistically enhanced the gefitinib-sensitivity of pancreatic cancer Panc-1 and Miapaca-2 cells (P<0.05), and IC50 of gefitinib on two cells were reduced by over 50%. Compared with single treatment, the combined treatment of BEA and gefitinib promoted the apoptosis and up-regulated the expressions of apoptosis-relatedproteins (cleaved-PARP and Bax), but reduced the apoptosis-inhibitory protein Bcl-2 (all P<0.05 or P<0.01). Moreover, the inhibitory effect of BEA on STAT3 activation in Panc-1 cells was in a dose-dependent mannar (P<0.01). BEA stabilizes its binding to STAT3 by forming hydrogen bonds with Lys-591 and Ser-613 of STAT3; in the meanwhile, BEA stabilized inthebinding site of STAT3, there by blocking STAT3 dimerization to enhance the drug sensitivity. Conclusion: Combined use of BEA and gefitinib could significantly inhibit the proliferation and induce apoptosis of Panc-1 and Miapaca-2 cells, which might be mediated by the inhibition of BEA on STST3.
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AIM:To study the cisplatin-sensitization effect and mechanism of tripterygium glycosides on cisplatin-resistant human epithelial ovarian cancer cells (SKOV3/DDP).METHODS:The SKOV3/DDP cells in exponential phase of growth were randomly divided into eight groups:blank control group,10 μg/mL DDP group,50 μg/mL GTW group,800 μg/mL GTW group,3 200 μg/mL GTW group,10 μg/mL DDP + 50 μg/mL GTW group,10 μg/mL DDP + 800 μg/mL GTW group and 10 μg/mL DDP + 3 200 μg/mL GTW group.Cell counting kit 8 and flow cytometry and western blot were used to detect the growth inhibiting rate and apoptosis rate and relative expression of GST-π,MDR1,STAT3,p-STAT3 of SKOV3/DDP cells of every group.RESULTS:DDP and GTW produce an additive effect when used concurrently in inhibiting growth of SKOV3/DDP cells.800 μg/mL GTW or 3 200 μg/mL GTW combined with 10 μg/mL DDP can significantly induce apoptosis of SKOV3/DDP cells and downregulate the expression of p-STAT3 (P ＜ 0.05).CONCLUSION:GTW can significantly enhance sensitivity of SKOV3/DDP cells to DDP.The underlying mechanism may be related with down-regulating the expression of p-STAT3 in STAT3 pathway.
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Objective The objective of this study was to investigate the role of sulindac in sensitization effects of NF-κB on apoptosis induced by TNF-α in human breast cancer.Methods The human breast cancer MCF-7 cell line was added sulindal in the logarithmic growth phase and the final concentrations of sulindac were 0.5 and 1.0 mmol/L.The cells in control group was cultured without adding succinic acid.After sulindac treatment for 48 h,flow cytometry,MTT and Western blotting were used to analyze the effect and mechanism of cell growth in MCF-7 cells.Results The inhibitory rate of cell proliferation was(29.17±1.23)% and(38.15±1.51)% in MCF-7 cells treated with 0.5 and 1.0 mmol/L of Sulindac for 48 h,respectively,when compared to the control group(1.15 ± 0.02)%(P<0.05).Compared with the control group,0.5 and 1.0 mmol/L of sulindac were significantly increased the G0/G1 phase in MCF-7 cells(P<0.05).The apoptosis rate of sulindac in MCF-7 cells was significantly higher than that in the control group(P<0.05).The expression levels of TNF-α were(2.09±0.67)% and(1.18±0.09)% in the concentrations of 0.5 and 1.0mmol/L sulindac,respectively,in MCF-7 cells when compared to the control group(7.42±0.56)%.Conclusion Sulindac has a certain effect on the growth of human breast cancer cells,which can promote the prolongation of cell cycle at the G0/G1 phase and improve sensitization of apoptosis.This mechanism may be related to the inhibition of TNF-α activity.
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PURPOSE: For tumor growth, invasion and metastasis, a cascade of linked sequential biological events is essential; overproduction of growth factors, activation of proteolytic enzymes, induction of tumor angiogenesis, and enhanced tumor cell motility and attachment. We tried to test whether the biological therapy against the biological targets can modulate the specific biological characteristics, and furthermore increased anti-tumor effects can be induced when the biological therapy and cytotoxic chemotherapy were combined. MATERIALS AND METHODS: YCC-1, 2, 3, 7, and AGS human gastric cancer cell lines were used in these studies. Pentosan polysulfate (PPS) as a heparin-binding growth factor (HBGF) inhibitor, Tranexamic acid as a plasmin inhibitor, Adriamycin as a chemotherapeutic agent, were selected. The methods were Northern blot analysis for the detection of Midkine (MK) expression, soft agar assay for autocrine tumorigenicity. The expression of uPA, PAI-1 was determined by ELISA, while the MMPs activities were evaluated by zymography. The effects of each drug on tumorigenicity and tumor cell proliferation were evaluated by soft agar assay and cell proliferation assay, respectively. RESULTS: YCC-3, 7, AGS cell lines expressed MK mRNA, whereas YCC-1, 2 did not. YCC-2 cell line showed increased expression of uPA and MMP activities. Only MK expressing YCC-3 and 7 cell lines showed the tumorigenicity. PPS suppressed the colony forming activities as much as Adriamycin did (PPS; 8~24%, Adriamycin; 12~40%), but it showed only cytostatic effects in cell proliferation assay (PPS; 60~103%, Adriamycin; 22~97%). When PPS was combined with Adriamycin on the Adriamycin resistant, MK expressing YCC-7 cell line, the growth inhibition rate increased up to 84%, while that of PPS or Adriamycin single treatment was 40%, 22%, respectively (p=0.001). CONCLUSION: The modulation of specific biological targets can induce the anti-tumor effects. This suggests the possible clinical application of biological therapy in gastric cancer.