SW480 Human Colon Cancer Cells Research Articles

Resveratrol‐Related Dehydrodimers: Laccase‐Mediated Biomimetic Synthesis and Antiproliferative Activity

AbstractSeven resveratrol‐related monomeric stilbenoids were submitted to biomimetic oxidative coupling in the presence of laccase from Trametes versicolor (TvL), and gave racemic dihydrobenzofuran dehydrodimers (±)‐15 to (±)‐21. These products, after spectral characterization, were submitted to an antiproliferative activity bioassay against SW480 human colon cancer cells. Five racemates were found to be active, and were resolved by chiral HPLC. The pure enantiomers were subjected to circular dichroism measurements to establish their absolute configurations at C‐7 and C‐8. These enantiomerically pure compounds were submitted to the antiproliferative activity assay towards SW480 cells, and were all shown to be active with IC50 values in the approximate range 20–90 μM. In some cases, a significant difference between the activity of the 7R,8R and 7S,8S enantiomers was observed, but a defined configuration of the stereogenic centers does not appear to be a structural requirement for the activity. The comparison between the most active compounds and the inactive ones strongly suggests that the presence of a methoxy group in the position ortho to the C‐4 hydroxy group is highly detrimental to the activity.

인체 대장암 세포주 SW480에서 재배 와송의 세포 사멸 유도 효과

재배 와송의 항암효과를 입증하기 위해 SW480 대장암세포에서 재배 와송 추출물의 apoptosis 유도 효과 및 그 기전에 미치는 영향에 대해 알아보았다. 재배 와송과 천연 와송 메탄올 추출물의 암세포 성장 억제능을 측정한 결과, 재배 와송은 천연 와송과 유사하게 농도 의존적으로 높은 암세포 증식억제효과를 보였으며 특히 농도 300 <TEX>${\mu}g$</TEX>/mL의 재배 와송 메탄올 추출물에서는 천연 와송 메탄올 추출물 보다 더 높은 억제 효과를 나타내었다. 또한 재배 와송 메탄올 추출물을 분획하여 얻은 각각의 물, 헥산, 클로로포름, 에틸아세테이트 및 부탄올 분획물 중 와송 클로로포름 분획물에서 암세포의 증식 억제효과가 가장 높게 나타났다. 이러한 와송 클로로포름 분획물의 apoptosis 유도 효과는 Sub-G1기의 함량 증가와 핵의 응축 및 apoptotic bodies 생성 그리고 DNA 분절을 통해 나타났다. 한편, 와송 클로로포름 분획물의 caspase 활성은 caspase inhibitor 처리군에서 암세포의 증식 억제효과가 확연히 저해됨을 나타내었으며 각각의 caspase 활성 중 caspase-3 및 -9의 활성을 증가시켰다. 또한 와송 클로로포름 분획물은 apoptosis 관련 단백질들인 Bid, Bcl-2 및 PARP의 발현을 농도 의존적으로 감소시켰으며 tBid 및 Bax 단백질의 발현을 현저하게 증가시켰다. 본 연구 결과, 재배 와송과 천연 와송은 유사한 암세포 성장 억제 효과를 보였으며 재배 와송의 클로로포름 추출물은 caspase 의존적인 경로를 통해 apoptosis를 일으켜 세포 사멸 효과를 나타내는 것을 확인할 수 있었다. This study was performed to elucidate the anticancer activities and the mechanism of chloroform fractions from cultivated Orostachys japonicus (CFCOJ) in human colon cancer cells. CFCOJ markedly decreased viable cell numbers in both a dose-dependent and time-dependent manner within SW480 cells. Cell death induced by CFCOJ increased cell populations in the sub-G1 phase, as well as the formation of apoptotic bodies, nuclear condensation, and induced DNA fragmentation. CFCOJ-induced apoptosis was associated with the activation of initiator caspase-8 and -9, as well as the effector caspase-3. CFCOJ also stimulated Bid cleavage, indicating that the apoptotic action of caspase-8-mediated Bid cleavage leads to the activation of caspase-9. CFCOJ increased the expression of the proapoptotic protein, Bax, and decreased the expression of the antiapoptotic protein, Bcl-2. These results indicate that CFCOJ exert anticancer effects on human colon cancer SW480 cells through a caspase-dependent apoptotic pathway.

Rosiglitazone and AS601245 Decrease Cell Adhesion and Migration through Modulation of Specific Gene Expression in Human Colon Cancer Cells

PPARs are nuclear receptors activated by ligands. Activation of PPARγ leads to a reduction of adhesion and motility in some cancer models. PPARγ transcriptional activity can be negatively regulated by JNK-mediated phosphorylation. We postulated that the use of agents able to inhibit JNK activity could increase the effectiveness of PPARγ ligands. We analysed the effects of rosiglitazone (PPARγ ligand) and AS601245 (a selective JNK inhibitor) alone or in association on adhesion and migration of CaCo-2, HT29, and SW480 human colon cancer cells and investigated, through microarray analysis, the genes involved in these processes. Cell adhesion and migration was strongly inhibited by rosiglitazone and AS601245. Combined treatment with the two compounds resulted in a greater reduction of the adhesion and migration capacity. Affymetrix analysis in CaCo-2 cells revealed that some genes which were highly modulated by the combined treatment could be involved in these biological responses. Rosiglitazone, AS601245 and combined treatment down-regulated the expression of fibrinogen chains in all three cell lines. Moreover, rosiglitazone, alone or in association with AS601245, caused a decrease in the fibrinogen release. ARHGEF7/β-PIX gene was highly down-regulated by combined treatment, and western blot analysis revealed that β-PIX protein is down-modulated in CaCo-2, HT29 and SW480 cells, also. Transfection of cells with β-PIX gene completely abrogated the inhibitory effect on cell migration, determined by rosiglitazone, AS601245 and combined treatment. Results demonstrated that β-PIX protein is involved in the inhibition of cell migration and sustaining the positive interaction between PPARγ ligands and anti-inflammatory agents in humans.

Liriodenine induces G1/S cell cycle arrest in human colon cancer cells via nitric oxide- and p53-mediated pathway

Liriodenine is an aporphine alkaloid compound extracted from the leaves of Michelia compressa var. lanyuensis. It had been reported to have an anti-colon cancer effect, but the mechanism remains unclear. In the present study, the antiproliferative mechanisms of liriodenine were investigated in the human colon cancer SW480 cells. Flow cytometry analysis indicated that liriodenine notably induced the G1/S phase arrest. The G1/S phase cycle-related proteins analysis illustrated that the expressions of cyclin-dependent kinase (CDK) 2, CDK4 and CDK6, and of cyclin D1 and A, as well as the phosphorylation of retinoblastoma tumor suppressor protein (ppRB) were found to be markedly reduced by liriodenine, whereas the protein levels of the CDK inhibitors (CKIs), p21 and p27 were increased. Moreover, the intracellular nitric oxide (NO) production, protein levels of inducible NO synthase (iNOS) and, p53 were increased. The p53 overexpression was a downstream event of NO production in liriodenine-induced G1/S-arrested SW480 cells, and the up-regulation of p21 and p27 was found to be mediated by a p53-dependent pathway. The inhibition of p53 by pifithrin-α (PFT-α), down-regulation of p21 and p27 by siRNA, or NO reduction by S-ethylisothiourea (ETU) entirely abolished the liriodenine-induced G1/S phase arrest. We concluded that liriodenine potently inhibited the cell cycle of SW480 cancer cells via NO- and p53-dependent G1/S phase arrest pathway. These results suggest that liriodenine might be a powerful agent against colon cancer.

Wnt/β-Catenin Signaling Mediates the Antitumor Activity of Magnolol in Colorectal Cancer Cells

Abnormal activation of the canonical Wnt/β-catenin pathway and up-regulation of the β-catenin/T-cell factor (TCF) response to transcriptional signaling play a critical role early in colorectal carcinogenesis. Therefore, Wnt/β-catenin signaling is considered an attractive target for cancer chemotherapeutic or chemopreventive agents. Small molecules derived from the natural products were used in our cell-based reporter gene assay to identify potential inhibitors of Wnt/β-catenin signaling. Magnolol, a neolignan from the cortex of Magnolia obovata, was identified as a promising candidate because it effectively inhibited β-catenin/TCF reporter gene (TOPflash) activity. Magnolol also suppressed Wnt3a-induced β-catenin translocation and subsequent target gene expression in human embryonic kidney 293 cells. To further investigate the precise mechanisms of action in the regulation of Wnt/β-catenin signaling by magnolol, we performed Western blot analysis, real-time reverse transcriptase-polymerase chain reactions, and an electrophoretic mobility shift assay in human colon cancer cells with aberrantly activated Wnt/β-catenin signaling. Magnolol inhibited the nuclear translocation of β-catenin and significantly suppressed the binding of β-catenin/TCF complexes onto their specific DNA-binding sites in the nucleus. These events led to the down-regulation of β-catenin/TCF-targeted downstream genes such as c-myc, matrix metalloproteinase-7, and urokinase-type plasminogen activator in SW480 and HCT116 human colon cancer cells. In addition, magnolol inhibited the invasion and motility of tumor cells and exhibited antitumor activity in a xenograft nude mouse model bearing HCT116 cells. These findings suggest that the growth inhibition of magnolol against human colon cancer cells can be partly attributed to the regulation of the Wnt/β-catenin signaling pathway.

Tu1308 Predictors and Prevalence of Corticosteroid use in IBD

(median 560.2 ng/ml, n= 5); 2) patients with quiescent IBD without dysplasia (51.8 ng/ml, n=6), or 3) patients with sporadic colon cancers (84.2 ng/ml, n=6), compared to patients with colonic adenomas (2.2 ng/ml, n=8) or healthy controls (10.8 ng/ml, n=6). CHI3L1 staining was strong in triangular-shaped cells (presumably stem-like cells) and Paneth cells, which showed typical cytoplasmic granular staining at the crypt base. In addition, occasional neuroendocrine-like cells in the crypts were intensely stained in IBD patients harboring remote dysplasia.While all patients with IBD/dysplasia (n=7) showed strong CHI3L1 staining, no adenomas (n=10) and only 35.7% sporadic colon cancers (n=14) were CHI3L1 positive. Purified CHI3L1 (80 ng/ml) significantly up-regulated a restricted number of genes, including IRAK1, IkBα, NFkBp65 and MyD88 in SW480 human colon cancer cells. CHI3L1 also induced a dose-dependent increase in IkBα phosphorylation and stimulated BrdU-incorporation into Colo205 and SW480 colon cancer cells. Finally, CHI3L1 induced a 6-fold increase in SW480 cell migration by Boyden chamber assay. Conclusions: Elevated CHI3L1 likely contributes to proliferation, migration and neoplastic transformation of CECs under inflammatory conditions. Furthermore, fecal CHI3L1 is a promising and non-invasive biomarker to detect individuals harboring IBD-associated neoplasia. Support: NIH DK80070, DK74454, AGA Bridging Award, and Broad Foundation to EM.

Su1869 DCAMKL-1 Regulates Pluripotency Factors Oct4, SOX2 and KLF4 via miR-145 MicroRNA Dependent Mechanism

Our current study investigated the effect of PHLPP expression on the efficacy of chemotherapeutic drugs in colon cancer cells. Both PHLPP isoforms, PHLPP1 and PHLPP2, were either knocked down or overexpressed in SW480 and HT29 human colon cancer cells, and the rate of cell proliferation and apoptosis were measured upon drug treatment. Specifically, the cells were treated with different concentrations of oxaliplatin, PI3K inhibitor (LY294002), or rapamycin for 48 hours and cell proliferation was determined using MTS assays. Our results showed that knockdown of both PHLPP isoforms resulted in a decrease in the sensitivity to all drugs tested, whereas overexpression of PHLPP enhanced the anti-proliferation effect of these drugs. Moreover, we assessed the effect of the chemotherapy drugs in inducing cell death by monitoring the appearance of apoptotic markers including cleaved PARP and Caspase-3. Similarly, knockdown of both PHLPP isoforms rendered the cells resistant to apoptosis upon drug treatment. In summary, we have identified PHLPP as a critical factor in determining the drug sensitivity in the chemotherapeutic treatment of colon cancer. Adding yet another novel function of PHLPP and reasoning for the possible use of PHLPP as a therapeutic target in colon cancer.

Su1871 Lactate Dehydrogenase-a Induction as an Early Metabolomic Marker of Colon Carcinogenesis: Potential Target for Chemoprevention

Our current study investigated the effect of PHLPP expression on the efficacy of chemotherapeutic drugs in colon cancer cells. Both PHLPP isoforms, PHLPP1 and PHLPP2, were either knocked down or overexpressed in SW480 and HT29 human colon cancer cells, and the rate of cell proliferation and apoptosis were measured upon drug treatment. Specifically, the cells were treated with different concentrations of oxaliplatin, PI3K inhibitor (LY294002), or rapamycin for 48 hours and cell proliferation was determined using MTS assays. Our results showed that knockdown of both PHLPP isoforms resulted in a decrease in the sensitivity to all drugs tested, whereas overexpression of PHLPP enhanced the anti-proliferation effect of these drugs. Moreover, we assessed the effect of the chemotherapy drugs in inducing cell death by monitoring the appearance of apoptotic markers including cleaved PARP and Caspase-3. Similarly, knockdown of both PHLPP isoforms rendered the cells resistant to apoptosis upon drug treatment. In summary, we have identified PHLPP as a critical factor in determining the drug sensitivity in the chemotherapeutic treatment of colon cancer. Adding yet another novel function of PHLPP and reasoning for the possible use of PHLPP as a therapeutic target in colon cancer.

Abstract 3818: Arsenic hexaoxide (As4O6) shows anticancer effects on human colon cancer cells in vitro and in vivo

Abstract Arsenic hexaoxide (As4O6) has been used as a folk remedy for the treatment of cancer since the late 1980's in Korea, and evidence suggests that As4O6-induced cell death pathway was different from that of As2O3. Here, we investigated the anticancer activities of As4O6 on SW620 human colon cancer cells. As4O6 induced cell death in a dose-dependent manner. The cell death was caspase-independent. In addition, the apoptosis was associated with suppression of p-Akt and activation of p-P38. As4O6 suppressed TNF-induced NF-κB activation through suppression of phosphorylation of IαB. As4O6 also suppressed NF-κB-regulated genes (Bcl-2, XIAP, and Bcl-xL) which are involved in anti-apoptosis. In animal experiments, As4O6 inhibited tumorigenicity of SW620 cells in a xenograft mouse model without showing any harmful effects on mice. As4O6 significantly inhibited intratumoral microvessel density. However, the inhibitory effects of As4O6 on NF-κB was minimal. In summary, in vitro study indicates that the As4O6 have anti-cancer effects on SW620 human colon cancer cells through inducing apoptosis by inhibiting anti-apoptotic molecules and in vivo study suggested that As4O6 should have additional anti-angiogenic activity. This study provides the evidence that As4O6 might be useful in the treatment of human colon cancer. [This study was supported by a grant from the National R&amp;D Program for Cancer Control, Ministry for Health, Welfare &amp; Family Affairs, Republic of Korea (0820050), and National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2011-0007389)] Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3818. doi:1538-7445.AM2012-3818

Abstract 1628: Tumor suppressor gene demethylation and reactivation in human colon cancer cells by black raspberry anthocyanins

Abstract Our laboratory has shown that the anthocyanins (ACs) in black raspberries (BRBs) are responsible for much of their chemopreventive effects in the rat esophagus. The present study was undertaken to determine the effects of BRB ACs on human colon cancer cells in vitro. Three days of AC treatment at 5 and 25 μg/ml medium significantly decreased cell proliferation and increased apoptosis in HCT116, Caco2, and SW480 human colon cancer cell lines. The ACs also reduced the activities and protein expression levels of DNA methyltransferases 1 and 3 (DNMT1, DNMT3) in all three cell lines. Promoter methylation of p16 (CDKN2A) and the Wnt pathway inhibitors, Sfrp2, Sfrp5 and Wif1, was decreased by AC treatment resulting in increased mRNA expression levels of all three Wnt inhibitors. ACs did not alter global methylation LINE-1. DNMT1 and DNMT3B knockout (KO) HCT116 cells were generated using siRNA to determine the role of these methyltransferases in AC-induced demethylation. In DNMT1 KO cells, the promoter methylation of Sfrp5 was reduced when compared with wild type HCT116 cells. AC treatment further reduced promoter methylation of Sfrp5 in DNMT1 KO cells suggesting that the ACs targeted protein(s) other than DNMT1 to regulate methylation. Promoter methylation of Sfrp5 was decreased to almost zero by treatment of DNMT3B KO cells with ACs. Interestingly, promoter methylation of p16 was reduced in both DNMT1 and DNMT3B KO cells, and AC treatment further reduced p16 methylation in both lines. In conclusion, these results suggest that ACs demethylated and reactivated tumor suppressor genes through regulation of DNMT1 and DNMT3B. This research was supported by NCI grant CA148818. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1628. doi:1538-7445.AM2012-1628

Abstract 252: Altered caspase-8 localization and decreased caspase-8 sumoylation in TRAIL-resistant normal human fibroblasts

Abstract TNF-related apoptosis-inducing ligand (TRAIL)-mediated cell death is currently being utilized in newly developed cancer therapies. The molecular basis of normal cell resistance to TRAIL-mediated apoptosis, and thus therapeutic index, remains largely unexplored. We previously investigated TRAIL sensitivity in normal fibroblasts (HFF, WI-38, MRC-5) and found that normal fibroblasts have decreased protein expression of initiator caspase-8 that is required for complete TRAIL signaling. We examined caspase-8 stability in cycloheximide treated normal fibroblasts and SW480 human colon cancer cells. Normal fibroblast caspase-8 stability was found to be similar to SW480 cells. Additionally, we investigated caspase-8 modulation in normal fibroblasts to uncover any drug treatments or modified growth conditions that result in increased caspase-8 protein expression and enhanced susceptibility to TRAIL-mediated apoptosis. Normal fibroblasts treated for 24, 48, and 72 hours with non-lethal doses of histone deacetylase inhibitor Trichostatin A or DNA methylation inhibitor 5-azacytidine had no change in caspase-8 protein expression. Our results suggest epigenetic silencing of caspase-8 is not responsible for TRAIL resistance in normal fibroblasts. However, normal fibroblasts serum starved with media containing 0.5% fetal calf serum for 48 hours, resulted in increased caspase-8 protein expression but not effector caspase-3 expression. Serum starved normal fibroblasts treated with TRAIL had increased caspase-3 activity and an increase in the percentage of sub-G1 positive cells compared to TRAIL treated cells in normal growth media. No increase in TRAIL-mediated apoptosis was observed in serum starved SW480 cells. Since previous studies have detected caspase-8 targets in both the cytoplasm and nucleus, we examined caspase-8 localization in normal fibroblasts. Little caspase-8 was found in nuclear extracts isolated from normal fibroblasts. Alternatively, SW480 caspase-8 expression was observed in both cytoplasmic and nuclear fractions. Sumoylated caspase-8 (p75), previously found to be associated with caspase-8 nuclear localization, was noted in nuclear fractions in both normal fibroblasts and SW480 cells. Yet, like total caspase-8 expression, sumoylated caspase-8 expression was found to be decreased in normal fibroblasts compared to SW480 colon cancer cells. Thus, decreased nuclear caspase-8 may be a contributing factor in normal fibroblast resistance to TRAIL-mediated apoptosis. Our current studies are focused on further analysis of caspase-8 sumoylation/desumoylation as well as caspase-8 post-translational modifications that may suppress caspase activity and nuclear translocation. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 252. doi:1538-7445.AM2012-252

Abstract 2296: Aldose reductase inhibition prevents human colon cancer cells growth by miR-21 and FOXO3a-mediated regulation of PTEN

Abstract We have shown earlier that the inhibition of aldose reductase (AR), a NADPH-dependent aldo-keto reductase, prevents growth factor-induced proliferation of colon cancer cells in vitro and in vivo. Recent studies indicate that changes in microRNA (miRNA) expression can contribute to cancer by modulating the functional expression of critical genes involved in cancer growth and metastasis. However, the molecular mechanism(s) by which AR regulates miRNA expression and their dependent mitogenic effects in cancer cells is not known. Therefore, we investigated how AR regulates growth factor -induced expression of miRNAs in colon cancer cells. Our results indicate that inhibition of AR significantly down-regulated growth factor-induced miR-21 expression in HT29, SW480 and Caco-2 human colon cancer cells. Further, AR inhibition also increased PTEN, a direct target of miR-21 that contributes cancer cell growth and invasion. Inhibition of AR also prevented the EGF-induced phosphorylation of PTEN and FOXO3a, which prevents cell proliferation. Treatment of human colon cancer cells with AR inhibitor, fidarestat, prevented the EGF-induced DNA binding activity of AP1, phosphorylation of PI3K, AKT, c-Jun and c-Fos. More importantly, in HT29 human colon adenocarcinoma xenograft tissues, miR-21 expression was lower, and PTEN and FOXO3a levels were significantly higher in AR inhibitor-treated mice compared to controls. Collectively, these results show a novel role of AR in mediation of growth factor-induced colon cancer cell proliferation by increasing miR-21 expression and inactivating or decreasing PTEN and FOXO3a through the ROS/PI3K/AKT/AP1 pathway, indicating that AR inhibitors could be used for the prevention/therapy of colon carcinogenesis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2296. doi:1538-7445.AM2012-2296

Depletion of mitochondrial fission factor DRP1 causes increased apoptosis in human colon cancer cells

Mitochondria play a critical role in regulation of apoptosis, a form of programmed cell death, by releasing apoptogenic factors including cytochrome c. Growing evidence suggests that dynamic changes in mitochondrial morphology are involved in cellular apoptotic response. However, whether DRP1-mediated mitochondrial fission is required for induction of apoptosis remains speculative. Here, we show that siRNA-mediated DRP1 knockdown promoted accumulation of elongated mitochondria in HCT116 and SW480 human colon cancer cells. Surprisingly, DRP1 down-regulation led to decreased proliferation and increased apoptosis of these cells. A higher rate of cytochrome c release and reductions in mitochondrial membrane potential were also revealed in DRP1-depleted cells. Taken together, our present findings suggest that mitochondrial fission factor DRP1 inhibits colon cancer cell apoptosis through the regulation of cytochrome c release and mitochondrial membrane integrity.

Syntheses and Cell-Based Phenotypic Screen of Novel 7-Amino pyrido[2,3-d]pyrimidine-6-carbonitrile Derivatives as Potential Antiproliferative Agents

A series of N-3-substituted 7-aminopyrido[2,3-d]pyrimidin-6-carbonitrile derivatives was readily synthesized and their anti-proliferative activities on five types of tumor cells were evaluated through a cell-based phenotypic screening approach. Compound 3k was found to be potent on human colon cancer SW620 cells with an IC50 value of 12.5 μM. Structural optimization of compound 3k led to compound 4a with improved anti-proliferative potency on SW620 cells with an IC50 value of 6.9 μM. Further cell-cycle analyses suggested that compound 4a induced apoptosis of SW620 cells in a concentration-dependent manner.

Anti-inflammatory effects of resveratrol occur via inhibition of lipopolysaccharide-induced NF-κB activation in Caco-2 and SW480 human colon cancer cells

Resveratrol, a polyphenol abundantly found in grapes and red wine, exhibits beneficial health effects due to its anti-inflammatory properties. In the present study, we evaluated the effect of resveratrol on inflammatory responses induced by lipopolysaccharide (LPS) treatment of human intestinal Caco-2 and SW480 cell lines. In the LPS-treated intestinal cells, resveratrol dose-dependently inhibited the expression of inducible NO synthase (iNOS) mRNA as well as protein expression, resulting in a decreased production of NO. In addition, Toll-like receptor-4 expression was significantly diminished in LPS-stimulated cells after resveratrol pre-treatment. To investigate the mechanisms by which resveratrol reduces NO production and iNOS expression, we examined the activation of inhibitor of κB (IκB) in LPS-stimulated intestinal cells. Results demonstrated that resveratrol inhibited the phosphorylation, as well as the degradation, of the IκB complex. Overall, these results show that resveratrol is able to reduce LPS-induced inflammatory responses by intestinal cells, interfering with the activation of NF-κB-dependent molecular mechanisms.

Role of the PRL-3 gene in the proliferation of human colon cancer SW480 cells

Role of the PRL-3 gene in the proliferation of human colon cancer SW480 cells

Development of a low-cost magnetic microfluidic chip for circulating tumour cell capture

The authors have developed a novel fabrication process for a selective micro-magnetic activated cell sorting (MACS) chip based on ferromagnetic material encapsulated micropillars (FMEMs), which is technically simple and low cost. The FMEM produces a high field gradient to magnetically attract, capture and hold cells on its interface. System test simulations were carried out to predict the efficacy of target capture and verify that the actual magnetic particles behaviour agreed well with model predictions. To determine the ability of the novel microMACS chip to capture circulating tumour cells (CTCs), SW620 human colon cancer cells were used in an in vitro flow model system and were able to be captured with the efficiency of 72.8%. The obvious accumulation of CTCs at a certain location on the chip suggested shear stress events at the pillar boundary may influence efficacy, and should be considered in further optimisation efforts.

Epigallocatechin-3-gallate inhibits proliferation and migration of human colon cancer SW620 cells in vitro

Epigallocatechin-3-gallate (EGCG) is the major polyphenolic constituent in green tea. The aim of this study is to investigate the effects of EGCG on proliferation and migration of the human colon cancer SW620 cells. Proliferation and migration of SW620 cells were induced by the protease-activated receptor 2-agonist peptide (PAR2-AP, 100 μmol/L) or factor VIIa (10 nmol/L), and analyzed using MTT and Transwell assays, respectively. The cellular cytoskeleton was stained with rhodamine-conjugated phalloidin and examined with a laser scanning confocal fluorescence microscope. The expression of caspase-7, tissue factor (TF) and matrix metalloproteinase (MMP)-9 in the cells was examined using QT-PCR, ELISA and Western blot assays. The activation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) and nuclear factor-kappa B (NF-κB) signaling pathways was analyzed with Western blot. Both PAR2-AP and factor VIIa promoted SW620 cell proliferation and migration, and caused cytoskeleton reorganization (increased filopodia and pseudopodia). Pretreatment with EGCG (25, 50, 75, and 100 μg/mL) dose-dependently blocked the cell proliferation and migration induced by PAR2-AP or factor VIIa. EGCG (100 μg/mL) prevented the cytoskeleton changes induced by PAR2-AP or factor VIIa. EGCG (100 μg/mL) counteracted the down-regulation of caspase-7 expression and up-regulation of TF and MMP-9 expression in the cells treated with PAR2-AP or factor VIIa. Furthermore, it blocked the activation of ERK1/2 and NF-κB (p65/RelA) induced by PAR2-AP or factor VIIa. EGCG blocks the proliferation and migration of SW620 cells induced by PAR2-AP and factor VIIa via inhibition of the ERK1/2 and NF-κB pathways. The compound may serve as a preventive and therapeutic agent for colon cancers.

A novel nitro-oxy substituted analogue of rofecoxib reduces human colon cancer cell growth

Rofecoxib is a specific COX-2 inhibitor able to exert antiproliferative activity against colorectal cancer cells. It was withdrawn from the market after the demonstration of an increased risk of cardiovascular complications after prolonged use. Nevertheless, it remains an interesting compound for laboratory research as an experimental COX-2 inhibitor. In this study, the antiproliferative activity of a novel dinitro-oxy-substituted analogue of rofecoxib (NO-rofe), potentially less cardiotoxic, has been investigated in vitro on human colon cancer cells and compared with the action of the parent drug. Due to the fact that COX-2 inhibition is the main characteristic of coxibs, we performed all experiments in COX-2-overexpressing (HT-29) and COX-2-negative (SW-480) human colon cancer cells, to elucidate whether the observed effects were dependent on COX-2 inhibition. Moreover, experiments were performed in order to evaluate whether COX-2 pharmacological inhibition may affect beta-catenin/E-cadherin signaling pathway. NO-rofe exerted a significant antiproliferative activity on COX-2 positive HT-29 human colon cancer cells, being less effective on the COX-2 negative SW-480 human colon cancer cell line. In particular, the rofecoxib analogue retained similar potencies with respect to COX-2 inhibition but was much more active than rofecoxib in inhibiting the growth of human colon cancer cells in vitro. In addition, this novel compound resulted in the induction of membrane β-catenin/E-cadherin expression, a feature that may significantly contribute to its antiproliferative activity.

Differential inhibition of human colon cancer cells by structurally similar flavonoids of citrus

A number of studies in the recent years have evaluated the anti-proliferative activity of flavonoids. Although certain studies investigated the structure–activity based on the phenotypic assays, no study has correlated the flavonoids structure with the ability to alter gene/protein expression. Present study was focused to understand the structure–function relationship of citrus flavonoids in terms of their ability to alter the gene expression in the colon adenocarcinoma cells. Eight structurally related flavonoids found in citrus were evaluated for their ability to inhibit colon cancer (SW480) cells, as well as change the expression of apoptosis related genes/proteins. Apigenin and quercetagetin demonstrated most significant inhibition of cell proliferation with 63.6% and 45.7% inhibition of cell growth at 200μM after 48h of incubation, respectively. The cell death was also confirmed by images of fluorescently tagged cells. Furthermore, up-regulation of Bax/Bcl2 protein ratio as well as activation of Caspase3 at 200μM at 48h confirmed the induction of apoptosis by apigenin and quercetagetin. In addition, results suggest that the change in Bax/Bcl2 ratio by apigenin and quercetagetin seems to be due to their ability to alter the expression of bax and bcl2 transcription. Results of the currents study suggest that among the citrus flavonoids, double bond between C2 and C3 and hydroxyl group at C3, C6 are highly decisive for the proliferation inhibition and apoptosis induction ability. Taken together, these results demonstrate that among the major flavonoids of citrus, apigenin and quercetagetin have potent anti-cancer activity through inducing apoptosis in SW480 human colon cancer cells.