Combination of cyclooxygenase-2 inhibitors and oxaliplatin increases the growth inhibition and death in human colon cancer cells

The cyclooxygenase-2 (COX-2) protein is highly expressed in a variety of human cancers and has been reported to promote tumor growth. Non-steroidal anti-inflammatory drugs such as etodolac and celecoxib have been shown to inhibit COX-2 activity and may play a role in the chemoprevention of cancer. Oxaliplatin is a third-generation platinum compound that exhibits a different spectrum of activity compared with cisplatin. Other cisplatin-resistant tumors can still respond to oxaliplatin. However, the anticancer ability of the combination of COX-2 inhibitors and oxaliplatin is still unknown. In this study, we investigated the effects of combination of COX-2 inhibitors and oxaliplatin on the cell growth and survival in human colon cancer cells. Treatments with etodolac (0.3-0.5 mM) or celecoxib (20-80 microM) for 24 h concentration-dependently induced the cytotoxicity in the RKO colon carcinoma cells. Etodolac and celecoxib did not alter the COX-2 protein levels but inhibited its enzyme activity to reduce prostaglandin E2 production. Furthermore, the cell survival was concentration-dependently decreased following oxaliplatin (1-100 microM, 24 h) treatment. Combination of oxaliplatin and etodolac additively increased the death and growth inhibition of RKO cells. Survivin, an inhibitor protein of apoptosis, mediates anti-apoptosis and promotes cell division in cancer cells. Oxaliplatin or COX-2 inhibitors significantly decreased the levels of survivin proteins. Moreover, survivin proteins were markedly diminished following co-treatment with oxaliplatin and etodolac. Together, this is the first report that combination of COX-2 inhibitors and oxaliplatin can increase the reduction of survivin protein expression, growth inhibition, and death in human colon cancer cells.     

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.     

The flavouring phytochemical 2-pentanone reduces prostaglandin production and COX-2 expression in colon cancer cells

Many phytochemicals found in the diet may prevent colon carcinogenesis by affecting biochemical processes in the colonic mucosa. Inflammation and subsequent elevation of the enzyme cyclooxygenase-2 (COX-2) are two such factors involved in the development of colon cancer, and inhibition of these processes could be important targets for chemoprevention. We have previously shown COX-2 inhibitory activity locally in the colon; e.g. in human fecal water from a group of vegetarians. In this study we focus on 2-pentanone, a frequently occurring compound in common foods such as banana and carrot. The aim was to study the inhibitory effects on prostaglandin production and COX-2 protein expression in tumour necrosis factor-alpha stimulated colon cancer cells (HT29) by radioimmunoassay and Western blotting. 2-Pentanone inhibited both prostaglandin production and COX-2 protein expression in human colon cancer cells. A concentration of 400 mumol/l 2-pentanone inhibited the prostaglandin production by 56.9+/-12.9% which is in the same range as the reference compound NS398 (59.8+/-7.6%). The two highest concentrations of 2-pentanone were further analyzed by Western blot, and 400 micromol/l and 200 micromol/l 2-pentanone resulted in a 53.3+/-9.6% and +/-27.1% reduction of the COX-2 protein levels respectively. Further studies on flavouring compounds, for example 2-pentanone, as colon cancer chemopreventives would be very valuable, and such results may contribute to future dietary recommendations.     

Rho-kinase inhibitor upregulates migration by altering focal adhesion formation via the Akt pathway in colon cancer cells

Although Rho-kinase is reportedly implicated in carcinogenesis and the progression of human cancers, its precise mechanism has not been fully elucidated. We recently reported that Rho-kinase negatively regulates epidermal growth factor (EGF)-stimulated cancer progression in SW480 colon cancer cells. In the present study, we investigated the effect of Rho-kinase on the migration of SW480 colon cancer cells and the mechanism underlying the involvement of Rho-kinase. Interestingly, (R)-(+)-trans-N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide, 2HCl (Y27632), a specific inhibitor of Rho-kinase, dose-dependently enhanced cell migration. SW480 cells spontaneously release vascular endothelial growth factor (VEGF), however, Y27632 had little effect on its release. While Rho-kinase, which is generally phosphorylated in unstimulated cells, was clearly suppressed by Y27632, exogenous VEGF did not affect its phosphorylation. Immunofluorescence microscopy revealed that Y27632 caused a dramatic change in the localization of focal adhesion components, vinculin, phosphorylated caveolin-1 and tyrosine-phosphorylated proteins in SW480 cells. Furthermore, Akt inhibitor restored the loss of vinculin-stained focal adhesion formation induced by Y27632. We also observed similar effects for Y27632 on the migration and localization of focal adhesion components such as vinculin in another colon cancer cell line, HT29. Taken together, these results strongly suggest that Rho-kinase negatively regulates the migration of colon cancer cells by altering focal adhesion formation via the Akt pathway.     

The role of cyclooxygenase-2-dependent signaling via cyclic AMP response element activation on aromatase up-regulation by o,p′-DDT in human breast cancer cells

o,p′-Dichlorodiphenyltrichloroethane (o,p′-DDT) is a DDT isomer and xenoestrogen that can induce inflammation and cancer. However, the effect of o,p′-DDT on aromatase is unclear. Thus, we investigated the effects of o,p′-DDT on aromatase expression in human breast cancer cells. We also examined whether cyclooxygenase-2 (COX-2) is involved in o,p′-DDT-mediated aromatase expression. Treatment with o,p′-DDT-induced aromatase protein expression in MCF-7 and MDA-MB-231 human breast cancer cells; enhancing aromatase gene expression, and enzyme and promoter activity. Treatment with ICI 182.780, a estrogen receptor antagonist, did not affect the inductive effects of o,p′-DDT on aromatase expression. In addition, o,p′-DDT increased COX-2 protein levels markedly, increased COX-2 mRNA expression and promoter activity, enhanced the production of prostaglandin E₂ (PGE₂), induced cyclic AMP response element (CRE) activation, and cAMP levels and binding of CREB. o,p′-DDT also increased the phosphorylation of PKA, Akt, ERK, and JNK in their signaling pathways in MCF-7 and MDA-MB-231 cells. Finally, o,p′-DDT induction of aromatase was inhibited by various inhibitors [COX-2 (by NS-398), PKA (H-89), PI3-K/Akt (LY 294002), EP2 (AH6809), and EP4 receptor (AH23848)]. Together, these results suggest that o,p′-DDT increases aromatase, and that o,p′-DDT-induced aromatase is correlated with COX-2 up-regulation, mediated via the CRE activation and PKA and PI3-kinase/Akt signaling pathways in breast cancer cells.     

微小RNA-152-3p 对结肠癌细胞增殖、迁移和侵袭的影响及其作用机制研究

目的探讨微小RNA(miR)-152-3p对结肠癌细胞的增殖、迁移和侵袭的影响及机制。方法2019年2月至2020年4月,将结肠癌SW480细胞分为miR-152-3p模拟物阴性对照(miR-NC)组、miR-152-3p模拟物(miR-152-3p)组、抑制物(anti-miRNC)组、miR-152-3p抑制物(anti-miR-152-3p)组、阴性对照(si-NC)组、沉默转移相关蛋白2(si-MTA2)组、miR-152-3p模拟物+空载体(miR-152-3p+pcDNA3.1)组、miR-152-3p模拟物+过表达MTA2(miR-152-3p+pcDNA3.1-MTA2)组,均用脂质体法转染至结直肠癌SW480细胞中,另取未转染结直肠癌SW480细胞记为Control组。采用实时荧光定量逆转录聚合酶链反应(qRT-PCR)检测miR-152-3p和MTA2 mRNA的表达水平;蛋白质印迹法测定蛋白的表达;MTT法检测细胞活性;Transwell检测细胞迁移和侵袭;双荧光素酶报告基因检测实验检测荧光活性。结果结肠癌HCT116、SW480及LoVo细胞中miR-152-3p表达分别为0.72±0.04、0.29±0.02、0.49±0.01,人正常结肠上皮细胞NCM460中miR-152-3p表达为1.06±0.12,与正常结肠上皮细胞NCM460相比,结肠癌细胞HCT116、LoVo、SW480中MTA2 mRNA和蛋白较高,miR-152-3p较低(P<0.05);Control组、miR-NC组、miR-152-3p组、si-NC组及si-MTA2组结肠癌SW480细胞吸光度分别为0.92±0.22、0.96±0.17、0.31±0.07、0.99±0.17及0.32±0.09,细胞迁移数分别为(172.00±23.52)个、(169.00±20.66)个、(53.67±12.22)个、(155.67±16.8)个及(54.33±8.74)个,细胞侵袭数分别为(124.67±10.02)个、(122.33±9.45)个、(26.00±5.00)个、(108.33±10.02)个及(42.00±4.00)个,与miR-NC 组相比,miR-152-3p 组SW480细胞中细胞周期蛋白D1(cyclin D1)、基质金属蛋白酶(MMP)-2及SW480细胞活性、迁移和侵袭数量均较低,周期素依赖激酶抑制剂p21(P21)及上皮钙黏素(E-cadherin)较高(P<0.05);与si-NC组相比,si-MTA2组SW480细胞中cyclin D1、MMP-2及SW480细胞活性、迁移和侵袭数量均较低,P21及E-cadherin较高(P<0.05)。转染miR-152-3p和MTA2野生型表达载体的结肠癌SW480细胞荧光素酶活性显著降低(P<0.05)。相比miR-152-3p+pcDNA3.1组,miR-152-3p+pcDNA3.1-MTA2组SW480细胞中P21、E-cadherin的表达较低,MTA2、cyclin D1、MMP-2蛋白的表达较高,SW480细胞活性、迁移、侵袭数量较高(P<0.05)。结论miR-152-3p可能通过下调MTA2抑制结肠癌细胞的增殖、迁移和侵袭。     

Capsaicin sensitizes TRAIL-induced apoptosis through Sp1-mediated DR5 up-regulation: involvement of Ca(2+) influx

Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in various malignant cells, several cancers including human hepatocellular carcinoma (HCC) exhibit potent resistance to TRAIL-induced cell death. The aim of this study is to evaluate the anti-cancer potential of capsaicin in TRAIL-induced cancer cell death. As indicated by assays that measure phosphatidylserine exposure, mitochondrial activity and activation of caspases, capsaicin potentiated TRAIL-resistant cells to lead to cell death. In addition, we found that capsaicin induces the cell surface expression of TRAIL receptor DR5, but not DR4 through the activation Sp1 on its promoter region. Furthermore, we investigated that capsaicin-induced DR5 expression and apoptosis are inhibited by calcium chelator or inhibitors for calmodulin-dependent protein kinase. Taken together, our data suggest that capsaicin sensitizes TRAIL-mediated HCC cell apoptosis by DR5 up-regulation via calcium influx-dependent Sp1 activation.     

Different involvement of DNA methylation and histone deacetylation in the expression of solute-carrier transporters in 4 colon cancer cell lines

The purpose of this study on the involvement of epigenetic control of the expression of solute carrier (SLC) transporters by DNA methylation and histone deacetylation in 4 colon cancer cells is to find the epigenetic control mechanisms of drug transporters in colon cancers. Human colon cancer cell lines (HCT116, HT29, SW48, SW480) were treated with 5-aza-2'-deoxycytidine (DAC), as a DNA methyltransferase inhibitor, followed by trichostatin A (TSA), as a histone deacetylase inhibitor. The mRNA expression and DNA methylation of several SLC transporters were analyzed by real-time polymerase chain reaction (PCR) and methylation-specific PCR, respectively. Among 12 SLC transporters possessing cytosine-phosphate-guanine (CpG) islands, thiamine transporter 2 (THTR2) (SLC19A3) gene showed a correlation between its mRNA expression level and DNA methylation status. TSA treatment increased histone H3 acetylation of THTR2 promoter region in all 4 colon cancer cell lines examined. HCT116 and SW48 cells showed a lack of THTR2 mRNA expression and methylation of its promoter, and DAC treatment induced its re-expression. In addition, the co-treatment with DAC and TSA increased THTR2 mRNA expression more markedly than DAC treatment in HCT116 and SW48 cells. In HT29 and SW480 cells that showed little methylation of THTR2 promoter, TSA treatment induced THTR2 mRNA expression markedly, but DAC treatment did not. In the 4 colon cancer cells examined, THTR2 mRNA expression is down-regulated by DNA methylation and/or histone deacetylation.     

骨桥蛋白、转录因子Sp1在不同转移潜能的大肠癌细胞株中的表达

目的了解转录因子Sp1、骨桥蛋白OPN在不同转移潜能的人大肠癌细胞株中的表达。方法以体外建系的大肠癌细胞株SW480、SW620为研究对象,通过Real-timePCR、Western-blot、细胞免疫荧光化学染色方法从mRNA和蛋白水平分别检测Sp1、OPN的表达。结果Real-timePCR的结果提示sW480（Duke＇s B期）、SW620（Duke＇s C期）两株细胞株都表达SplmRNA、OPNmRNA,Western-blot检测Spl、0PN蛋白在两种大肠癌细胞株中均有表达,SW620细胞株Sp1、OPN表达水平高于SW480（P〈0.05）。结论Sp1、OPN在大肠癌细胞株SW480、SW620中均有表达,与大肠癌肿瘤分期、侵袭转移相关。     

Elevated gadd153/chop expression during resveratrol-induced apoptosis in human colon cancer cells

Resveratrol (3,4',5-tri-hydroxystilbene), a natural phytoalexin found at high levels in grapes and red wine, has been shown to induce anti-proliferation and apoptosis of human cancer cell lines. Resveratrol-induced dose-dependent apoptotic cell death in colon carcinoma cells, as measured by FACS analysis and internucleosomal DNA fragmentation assays. We demonstrate for the first time that resveratrol induce CCAAT/enhancer-binding protein-homologous protein (CHOP). Resveratrol-induced CHOP mRNA (and also protein) expression was inhibited by JNK specific inhibitor, but not ERK, p38 MAPK, PI3K and NF-kappaB inhibitors. Resveratrol-induced expression of CHOP involves the putative Sp1 site within the CHOP promoter region. Using a combination of the Sp1 cDNA transfection, the luciferase reporter assay and Sp1 inhibitor assay, we found that Sp1 site is required for resveratrol-mediated activation of the CHOP promoter. Suppression of CHOP expression by CHOP siRNA and treatment with mithramycin A attenuated resveratrol-induced apoptosis. Taken together, the present studies suggest that induction of CHOP protein may be involved, at least in part, in resveratrol-induced apoptosis.