JNK1 is required for sulindac-mediated inhibition of cell proliferation and induction of apoptosis in vitro and in vivo

Our previous studies demonstrated that sulindac, a non-steroidal anti-inflammatory drug, suppressed intestinal tumor formation in mouse, which is linked to the induction of wild-type p53-activated fragment 1 (p21WAF1, or p21). Here we showed that sulindac also required c-Jun N-terminal Kinase 1 (JNK1) to inhibit cell proliferation and induce apoptosis in vitro and in vivo. First, sulindac inhibited cell proliferation and induced apoptosis in colon cancer cell lines HCT116 with wild-type p21 or null p21, which were p21-dependent and were also associated with the induction of p21 and phosphorylation of JNK1. Second, sulindac increased apoptosis in JNK1^+/+ and JNK1^−/− mouse embryonic fibroblast (MEF) cells, but, the increase of apoptosis in JNK1^+/+ cells was more than that in JNK1^−/− cells. More interestingly, sulindac significantly inhibited cell proliferation in JNK1^+/+ cells, but the inhibition in JNK1^−/− cells markedly decreased. Further studies indicated that JNK1 was dramatically induced by sulindac in the JNK1^+/+ cells which correlated with the induction of p21. However, the induction of p21 in JNK1^−/− cells was less than that in JNK1^+/+ cells. Finally, we determined the expression of JNK1 in the intestinal mucosa of Apc^+/−, p21^+/+ mice, and found that sulindac significantly induced JNK1 phosphorylation, corresponding to the induction of p21, both in mRNA and protein levels. Our data indicates that sulindac-mediated proliferation inhibition and apoptosis induction were not only p21-dependent, but also required JNK1.     

Antitumor Effects of Fucoidan on Human Colon Cancer Cells via Activation of Akt Signaling

We identified a novel Akt signaling mechanism that mediates fucoidan-induced suppression of human colon cancer cell (HT29) proliferation and anticancer effects. Fucoidan treatment significantly inhibited growth, induced G1-phase-associated upregulation of p21WAF1 expression, and suppressed cyclin and cyclin-dependent kinase expression in HT29 colon cancer cells. Additionally, fucoidan treatment activated the Akt signaling pathway, which was inhibited by treatment with an Akt inhibitor. The inhibition of Akt activation reversed the fucoidan-induced decrease in cell proliferation, the induction of G1-phase-associated p21WAF1 expression, and the reduction in cell cycle regulatory protein expression. Intraperitoneal injection of fucoidan reduced tumor volume; this enhanced antitumor efficacy was associated with induction of apoptosis and decreased angiogenesis. These data suggest that the activation of Akt signaling is involved in the growth inhibition of colon cancer cells treated with fucoidan. Thus, fucoidan may serve as a potential therapeutic agent for colon cancer.     

Celecoxib inhibits the expression of survivin via the suppression of promoter activity in human colon cancer cells

We investigated the effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on human colon cancer cell lines to clarify the mechanisms underlying the chemopreventive effect of NSAIDs. Celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, induced apoptosis and strongly reduced the expression of an anti-apoptotic protein, survivin, in both protein and mRNA levels in HCT-116 cells. Subsequently, we conducted luciferase reporter assay using a reporter gene driven by the human survivin promoter. A series of analyses using luciferase reporter constructs containing fragments of the survivin promoter and electrophoretic mobility shift assay indicated that the -75/-66 bp region relative to the initiating codon was involved in celecoxib action to suppress survivin promoter activity. Celecoxib also suppressed the activity of TOPflash, T-cell factor reporter plasmid, and the reporter gene driven by the human cyclin D1 promoter, suggesting that this compound inhibited the expression of Wnt/beta-catenin signaling target genes. Further, we found that other NSAIDs including indomethacin, resveratrol, and SC-560 induced apoptosis and suppressed the expression of survivin and the Wnt/beta-catenin signaling pathway in HCT-116 cells, indicating that these effects were likely to be common among NSAIDs. Moreover, NSAIDs (celecoxib, SC-560 and indomethacin) also suppressed the expression of cyclin D1 and survivin on other colon cancer cell lines (DLD-1 and SW-620). Our results suggested that NSAIDs could inhibit proliferation and induce apoptosis in colon cancer cells by inhibition of survivin expression and the Wnt/beta-catenin signaling pathway.     

Anti-proliferation activity of total flavonoids isolated from Diospyros kaki L. f. leaves against human cancer celllines

OBJECTIVE To investigate the in vitro anti-proliferation activity of PLF against several human cancer cell lines and revealed its potentials as anticancer agent. METHODS The anti-proliferation activity of PLF against six human cancer cell lines and three normal human cell lines was evaluated by Alarma Blue method.The apoptosis induction of PLF in HCT116 cells was detected using high-content analysis with FITC-Annexin Ⅴ/propidium iodide(PI) double staining. The production of intracellular reactive oxygen species(ROS) induced by PLF was accessed using DHE dye. The ability of PLF to scavenge free radical was investigated by DPPH assay.RESULTS In a concentration of up to 30 mg·L~(-1), PLF showed moderate to high anti-proliferation activity against six different types of human cancer cells, but little cytotoxicity to normal human cells. PLF induced apoptosis and intracellular ROS in HCT116 human colon cancer cells. In addition, PLF showed strong DPPH free radical scavenging ability in the antioxidant assay. CONCLUSION PLF demonstrated significant inhibition against the proliferation of liver, breast, and colon cancer cells in vitro.The anti-proliferation activity of PLF against cancer cells was related to the promotion of oxidative stress and the induction of apoptosis. PLF can be a potential candidate as anticancer drug due to the activities shown in vitro and in vivo and worth further research.     

4种中药制剂对人肺癌A549细胞增殖的影响

目的　研究人肺癌A5 49细胞和乳腺癌MCF7细胞对市售 4种中药制剂 (斑蟊酸钠、苦参素、华蟾素和川芎素 )的敏感性 ,以及川芎素影响肺癌A5 49细胞增殖的可能机制。方法　采用MTT法测定药物对细胞增殖的抑制率和药物间的协同抑制作用 ;流式细胞法测定细胞周期。结果　4种中药对乳腺癌MCF7细胞的增殖均有不同程度的抑制作用 ,但只有川芎素可明显抑制肺癌A5 49细胞的增殖 ;川芎素与 3种化疗药物联合对A5 49细胞有协同作用 ;川芎素可诱导A5 49细胞凋亡。结论　斑蟊酸钠、苦参素和华蟾素对不同肿瘤细胞的抑制效果差异很大 ;川芎素不仅有抑制肿瘤细胞增殖的作用 ,还与化疗药物有协同效果 ;川芎素抑制A5 49细胞增殖的机制与其诱导细胞凋亡有关。