Activity In HT-29 Cells Research Articles

Oxidized Dietary Oil, High in Omega-3 and Omega-6 Polyunsaturated Fatty Acids, Induces Antioxidant Responses in a Human Intestinal HT29 Cell Line.

When oxidized, dietary oils generate products which have the potential to cause adverse effects on human health. The objective of the study was to investigate whether lipid oxidation products in an oxidized dietary oil can be taken up in intestinal cells, induce antioxidant stress responses and potentially be harmful. The in vitro cell model HT29 was exposed to camelina oil with different extents of oxidation, or only 4-hydroxy-2-hexenal (HHE) or 4-hydroxy-2-nonenal (HNE). The cellular content of HHE increased with an increasing extent of oxidation of the camelina oil added to the cell's growth media, whereas HNE did not show a similar trend. Deuterated HHE was taken up by the HT29 cells, with 140 µM HHE metabolized within 0.5-1 h. The low oxidation degree of the camelina oil increased the gene expression of antioxidant markers (GPX, ATF6, XBP1). The increase in the gene expression of SOD at medium oxidation levels of the oil might indicate different regulation mechanisms. Highly oxidized camelina oil and a low concentration of HHE, over time, induced SOD and catalase enzyme activity in HT29 cells. Oxidized camelina oil contains multiple oxidation products which can be responsible for the intracellular responses observed in HT29 cells, while HHE and HNE in combination with other oxidation products induce antioxidant defence responses.

Molecular Effects of Iodine-Biofortified Lettuce in Human Gastrointestinal Cancer Cells.

Considering the growing number of cancer cases around the world, natural products from the diet that exhibit potential antitumor properties are of interest. Our previous research demonstrated that fortification with iodine compounds is an effective way to improve the antioxidant potential of lettuce. The purpose of the present study was to evaluate the effect of iodine-biofortified lettuce on antitumor properties in human gastrointestinal cancer cell lines, gastric AGS and colon HT-29. Our results showed that extracts from iodine-biofortified lettuce reduce the viability and proliferation of gastric and colon cancer cells. The extracts mediated cell cycle arrest which was accompanied by inactivation of anti-apoptotic Bcl-2 and activation of caspases, as assessed by flow cytometry. However, extracts from lettuce fortified with organic forms of iodine acted more effectively than extracts from control and KIO3-enriched plants. Using quantitative PCR, we detected the increase in pro-apoptotic genes BAD, BAX and BID in AGS cells whereas up-regulation of cell cycle progression inhibitor CDKN2A and downregulation of pro-proliferative MDM2 in HT-29 cells. Interestingly, lettuce extracts led to down-regulation of pro-survival AKT1 and protooncogenic MDM2, which was consistent for extracts of lettuce fortified with organic form of iodine, 5-ISA, in both cell lines. MDM2 downregulation in HT-29 colon cancer cells was associated with RB1 upregulation upon 5-ISA-fortified lettuce extracts, which provides a link to the epigenetic regulation of tumor suppressor genes by RB/MDM2 pathway. Indeed, SEMA3A tumor suppressor gene was hypomethylated and upregulated in HT-29 cells treated with 5-ISA-fortified lettuce. Control lettuce exerted similar effects on RB/MDM2 pathway and SEMA3A epigenetic activation in HT-29 cells. Our findings suggest that lettuce as well as lettuce fortified with organic form of iodine, 5-ISA, may exert epigenetic anti-cancer effects that can be cancer type-specific.

Diclofenac down-regulates COX-2 induced expression of CD44 and ICAM-1 in human HT29 colorectal cancer cells.

Cyclooxygenase-2 (COX-2) is expressed in a variety of human colorectal cancer cells and can contribute to carcinogenesis. This study aimed to investigate the effect of diclofenac (DCF), a selective COX-2 inhibitor, on cell adhesion molecules and apoptosis in human colon adenocarcinoma cells. Levels of homing cell adhesion molecule (H-CAM, CD44), intercellular adhesion molecule-1 (ICAM-1, CD54), vascular cell adhesion molecule-1 (VCAM-1, CD106), and epithelial cell adhesion molecule (EpCAM, CD326) were evaluated in cancer cells overexpressing (HT29) or not expressing (HCT116) COX-2. Cell viability was determined by MTT assay, COX-2 protein levels and activity were assessed by immunofluorescence and fluorometric analysis, respectively. Endogenous levels of polyunsaturated fatty acids (PUFAs) were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) while expression of cell adhesion molecules was analyzed by flow cytometry. Annexin V-FITC/propidium iodide-labelling and fluorometric caspase-3 activity measurements were carried out to determine apoptosis. Flow cytometry analysis revealed that the percentage of CD44 and ICAM-1 staining in HCT116 cells was significantly lower compared to HT29 cells. In HT29 cells, phorbol 12-myristate 13-acetate (PMA) induced COX-2 expression and increased CD44 and ICAM-1 levels were down-regulated by diclofenac. Stimulation of COX-2 activity in HT29 cells via PMA significantly decreased diclofenac associated increase in PUFA levels. Treatment with both diclofenac and PMA significantly increased the number of apoptotic cells and caspase-3 activity in colon adenocarcinoma cells compared to control groups. In conclusion, diclofenac's effect to retard colorectal tumor growth and metastasis occurs in COX-2 overexpressing colon cancer cells by increased apoptosis and decreased expression of CD44 and ICAM-1.

Raw and Sous-Vide-Cooked Red Cardoon Stalks (Cynara cardunculus L. var. altilis DC): (Poly)phenol Bioaccessibility, Anti-inflammatory Activity in the Gastrointestinal Tract, and Prebiotic Activity.

The in vitro anti-inflammatory and prebiotic activity and the content and profile of bioaccessible (poly)phenols and catabolites of raw and sous-vide-cooked red cardoon (Cynara cardunculus L. var. altilis DC) were investigated during gastrointestinal (GI) digestion. Raw cardoon after in vitro GI digestion had 0.7% bioaccessible (poly)phenols, which protected against lipopolysaccharide-induced inflammation by counteracting IL-8, IL-6, TNF-α, and IL-10 secretions in differentiated Caco-2 cells. Contrarily, GI-digested sous vide cardoon showed higher (poly)phenol bioaccessibility (59.8%) and exerted proinflammatory effects in Caco-2 cells. (Poly)phenols were highly metabolized during the first 8 h of in vitro fermentation, and nine catabolites were produced during 48 h of fermentation. Colonic-fermented raw and sous-vide-cooked cardoon did not show anti-inflammatory activity in HT-29 cells but presented potential prebiotic activity, comparable to the commercial prebiotic FOS, by stimulating health-promoting bacteria such as Bifidobacterium spp. and Lactobacillus/Enterococcus spp. and by increasing the production of total SCFAs, especially acetate.

Dynamic chromatin association of IκBα is regulated by acetylation and cleavage of histone H4.

IκBs exert principal functions as cytoplasmic inhibitors of NF-kB transcription factors. Additional roles for IκB homologues have been described, including chromatin association and transcriptional regulation. Phosphorylated and SUMOylated IκBα (pS-IκBα) binds to histones H2A and H4 in the stem cell and progenitor cell compartment of skin and intestine, but the mechanisms controlling its recruitment to chromatin are largely unknown. Here, we show that serine 32-36 phosphorylation of IκBα favors its binding to nucleosomes and demonstrate that p-IκBα association with H4 depends on the acetylation of specific H4 lysine residues. The N-terminal tail of H4 is removed during intestinal cell differentiation by proteolytic cleavage by trypsin or chymotrypsin at residues 17-19, which reduces p-IκBα binding. Inhibition of trypsin and chymotrypsin activity in HT29 cells increases p-IκBα chromatin binding but, paradoxically, impaired goblet cell differentiation, comparable to IκBα deletion. Taken together, our results indicate that dynamic binding of IκBα to chromatin is a requirement for intestinal cell differentiation and provide a molecular basis for the understanding of the restricted nuclear distribution of p-IκBα in specific stem cell compartments.

Modulation of CT-genes transcriptional activity in HT-29 cells by irradiation with a linear accelerator.

e15218 Background: Cancer-testis antigens (CTAs) are used as targets in immunotherapeutic approaches based on gene-cell vaccines (GCV). In some cases, it is possible to use experimental combinatorial therapy regimens that combine radiation and GCV. Despite numerous studies of the expression of CTA in tumors of various locations, including colon tumors, the transcriptional activity of CT-genes in tumor tissue of the colon after radiation therapy remains poorly studied. The aim of the study was to analyze changes in the expression of CT-genes in HT-29 cells after irradiation with a linear accelerator. Methods: The study used human cell culture HT-29. For the model experiment, 7 Gy fractionation option was used (irradiation was carried out 5 times every 24 hours). Irradiation was performed on a Novalis TX linear accelerator (Varian, USA). The ratio of living and dead cells was calculated in a Goryaev chamber using a 0.4% trypan blue dye solution. After microscopy on the 5th day of irradiation, the cell line was removed from the vial substrate by Trypsin/Versen solution. RNA was isolated by the Chomczynski&Sacchi method. For cDNA synthesis a set of "REVERTA-L" reagents used. Expression of 16 CT genes (MAGE-A1, -A2, -A3, -A4, MAGE-B1, -B2, GAGE-1, -3, -4, MAGEC1, BAGE, XAGE3, NYESO1, SSX2, SCP1, PRAME1) was determined using the Real-Time qPCR method (reference genes — GAPDH and B2M). Statistical analysis was performed using univariate analysis of variance (ANOVA) with repeated measurements. Results: After 5 days of exposure at a dose of 7 Gy, only 20% of the initial number of HT-29 cells remained viable. It was found that irradiation was statistically significantly (p < 0.05) influenced the increase in the expression of genes MAGEA1 by 1.8 times, MAGEB1 by 6.8 times, BAGE by 1.6 times, CTAGE1 by 3.3 times and SSX2 by 5.8 times relative to intact cells. Conclusions: Thus, tumor cells exposed to radiation at a dose of 7 Gy show an increase in the expression of 5 CT-genes, which, in turn, can increase their immunogenic potential.

The fatty acid derivative palmitoylcarnitine abrogates colorectal cancer cell survival by depleting glutathione

Previous evidence suggests that palmitoylcarnitine incubations trigger mitochondrial-mediated apoptosis in HT29 colorectal adenocarcinoma cells, yet nontransformed cells appear insensitive. The mechanism by which palmitoylcarnitine induces cancer cell death is unclear. The purpose of this investigation was to examine the relationship between mitochondrial kinetics and glutathione buffering in determining the effect of palmitoylcarnitine on cell survival. HT29 and HCT 116 colorectal adenocarcinoma cells, CCD 841 nontransformed colon cells, and MCF7 breast adenocarcinoma cells were exposed to 0 μM, 50 μM, and 100 μM palmitoylcarnitine for 24-48 h. HCT 116 and HT29 cells showed decreased cell survival following palmitoylcarnitine compared with CCD 841 cells. Palmitoylcarnitine stimulated H2O2 emission in HT29 and CCD 841 cells but increased it to a greater level in HT29 cells due largely to a higher basal H2O2 emission. This greater H2O2 emission was associated with lower glutathione buffering capacity and caspase-3 activation in HT29 cells. The glutathione-depleting agent buthionine sulfoximine sensitized CCD 841 cells and further sensitized HT29 cells to palmitoylcarnitine-induced decreases in cell survival. MCF7 cells did not produce H2O2 when exposed to palmitoylcarnitine and were able to maintain glutathione levels. Furthermore, HT29 cells demonstrated the lowest mitochondrial oxidative kinetics vs. CCD 841 and MCF7 cells. The results demonstrate that colorectal cancer is sensitive to palmitoylcarnitine due in part to an inability to prevent oxidative stress through glutathione-redox coupling, thereby rendering the cells sensitive to elevations in H2O2. These findings suggest that the relationship between inherent metabolic capacities and redox regulation is altered early in response to palmitoylcarnitine.

Bound polyphenol from foxtail millet bran exhibits an antiproliferative activity in HT-29 cells by reprogramming miR-149-mediated aerobic glycolysis

Abstract Colorectal cancer (CRC) is an intractable intestinal tumor. Cancer cells prefer to aerobic glycolysis to meet the requirements of rapid proliferation. Hence, discovery of a bioactive molecule cold inhibit aerobic glycolysis, which is regarded as a effective strategies for prevention and treatment of CRC. In this study, we first discovered a foxtail millet bran-derived bound polyphenol (BPIS) with anti-proliferative activity in HT-29 cell (colon cancer cell lines) and its nude mice model. The data further indicated the anti-CRC active ingredients and molecular mechanisms of BPIS. Here we revealed that BPIS could act anti-proliferative activity in HT-29 cells depending on reversing aerobic glycolysis, and this effect was achieved by up-regulation of miR-149 expression by BPIS, which directly targeted the 3′-UTR of c-myc, thereby inhibiting PKM2-mediated aerobic glycolysis. Therefore, BPIS might be used as a new inhibitor of glycolysis for enhancing intestines health benefits.

Sulforaphane, a Chemopreventive Compound, Inhibits Cyclooxygenase-2 and Microsomal Prostaglandin E Synthase-1 Expression in Human HT-29 Colon Cancer Cells

Background: A high expression of prostaglandin E2 (PGE2) is found in colorectal cancer. Therefore, blocking of PGE2 generation has been identified as a promising approach for anticancer therapy. Sulforaphane (SFN), an isothiocyanate derived from glucosinolate, is used as the antioxidant and anticancer agents. Methods: HT-29 cells were treated with various concentrations of SFN and compared to untreated cells for the expression of microsomal prostaglandin E synthase-1 (mPGES-1), cyclooxygenase 2 (COX-2), hypoxia-inducible factor-1 (HIF-1), C-X-C chemokine receptor type 4 (CXCR4), vascular endothelial growth factor (VEGF), and matrix metalloproteinase (MMP)-2 and MMP-9 at the mRNA level. The PGE2 level was measured by ELISA assay. Apoptosis was evaluated by the proportion of sub-G1 cells. The activity of caspase-3 was determined using an enzymatic assay. HT-29 cell migration was assessed using a scratch test. Results: SFN preconditioning decreased the expression of COX-2, mPGES-1, HIF-1, VEGF, CXCR4, MMP-2, and MMP-9. An apoptotic effect of SFN was preceded by the activation of caspase-3 as well as accumulation of cells in the sub-G1 phase of the cell cycle. SFN decreased PGE2 generation and inhibited the in vitro motility/wound-healing activity of HT-29 cells. Conclusions: SFN anticancer effects are associated with antiproliferative, antiangiogenic, and antimetastatic activities arising from the downregulation of the COX-2/ mPGES-1 axis.

Abstract 1667: Design and development of a parthenolide-combretastatin hybrid drug (VA-11) with highly potent antimicrotubule and NF-kB inhibitory activities

Abstract Given the molecular complexity of cancers, their extreme heterogeneity and innate or acquired resistance to anticancer drugs, there is an increasing need for hybrid drugs that can effectively and simultaneously impact two or more targets triggering multiple cytocidal events in synergy to obtain superior chemo-sensitivities and prevent tumor resistance. Therefore, we developed a hybrid drug by combining the NF-kb inhibiting and oxidative stress-inducing parthenolide, a sesquiterpene lactone derived from the plant feverfew with the combretastatin A4 (CA4), a potent antimicrotubule and anti-angiogenesis agent. These hybrid compounds were synthesized by incorporating the α-methylene-γ-butyrolactone, an active component of parthenolide into the CA4 by replacing the unstable cis-double bond. The structural design of these hybrid compounds preserved the CA4 nucleus in the cis-configuration and prevented its isomerization into its biologically inactive trans-form. VA-11 was the highly potent among the different compounds prepared in specifically killing the tumor cells of various human cancer types at nano molar range. These included the colon (HT29, HCT116, SW640), breast (MDA-MB-231, SK-BR-3, MCF7), lung (A549, H1299, H460), brain (SF188, GBM10, GBM6, DAOY, T98G, U87MG) and pancreas (MIA-PaCa-2, PANC-1, BxPC-3). Particularly significant was that VA-11 was 10 times more potent than CA4 against the HT29 colon cancer cells. Various biochemical and immunocytochemical assays revealed that VA-11 retained the microtubule-disrupting effects of CA4, including microtubule depolymerization, the formation of aberrant mitotic spindles, and G2/M phase arrest. The hybrid drug also inhibited the polymerization of purified tubulins in vitro. Furthermore, VA-11 potently inhibited the formation of tubes in three-dimensional cultures of the HUVEC (Human umbilical Vein Cells), drastically decreasing the tube length and junctions at 1 μM concentration. The cancer cell migration /invasion, determined by transwell assays were also inhibited, and the inhibition was accompanied by increased E-cadherin levels through NF-κB/Snail pathway. Further, VA-11 inhibited the NF-κB activation, IκBα degradation, and IκB Kinase complex activity in HT29 cells tested in this study. VA-11 pretreatment significantly inhibited the IL-8 secretion induced by the cytokines such as LPS and/or TNF. These studies confirmed that VA-11 inhibits IκB kinase, resulting in stabilization of cytoplasmic IκBα, which in turn leads to inhibition of NF-κB translocation and attenuation of subsequent inflammatory responses and drug resistance. In conclusion, our results indicate that VA-11 represents a new prototype chemo drug with multiple mechanisms of action. Such hybrid anticancer drugs merit further development (supported by CPRIT grants RP130266 and RP170207 to KSS). Citation Format: Viswanath Arutla, Surendra R. Punganuru, Hanumantharao Madala, Kalkunte S. Srivenugopal. Design and development of a parthenolide-combretastatin hybrid drug (VA-11) with highly potent antimicrotubule and NF-kB inhibitory activities [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1667.

Vicenin-2 inhibits Wnt/β-catenin signaling and induces apoptosis in HT-29 human colon cancer cell line.

BackgroundColorectal cancer (CRC) is among highest prevailing cancers in the whole world, especially in western countries. For a diverse of reasons, patients prefer naturally occurring dietary substances over synthetic agents to prevent cancer. Vicenin-2 is largely available in a medicinal plant Ocimum sanctum and is an apigenin form, 6,8-di-C-glucoside, which has been reported to have a range of pharmacological values which includes antioxidant, hepatoprotective, anti-inflammatory and anti-cancer. This study was aimed to analyze the anti-proliferative effect of Vicenin-2 on human colon cancer cells via the Wnt/β-catenin signaling inhibition.MethodsMTT assay was used to assess the cell viability at different concentrations and time point. Vicenin-2 at a concentration of 50 µM (IC50) decreased the phosphorylated (inactive) glycogen synthase kinase-3β, cyclin D1, and non-p-β-catenin expressions in HT-29 cells, which were evidenced through western blot analysis.ResultsFurther, Vincenin-2 reduced the T-cell factor (TCF) / Leukocyte erythroid factor (LEF) reporter activity in HT-29 cells. Vicenin-2 also promoted substantial cell cycle arrest at the G2M phase of HT-29 cells, as well induced apoptosis in HT-29 cells, as revealed through flow cytometric analysis. Furthermore, immunoblot analysis showed that Vicenin-2 treatment enhanced the expression of Cytochrome C, Bax and caspase-3 whereas suppressed the Bcl-2 expression.ConclusionTogether, these results revealed that Vicenin-2 can act as a potent inhibitor of HT-29 cell proliferation and can be used as an agent against CRC.

Antitumor activity of Notch‑1 inhibition in human colorectal carcinoma cells.

This study investigated the roles of Notch-1 in colorectal carcinoma, to assess the mechanisms. The expression of Notch-1 and its ligand-Jagged1 was detected in human colorectal carcinoma, colorectal adenoma, paracancerous tissue and normal colorectal tissue by immunohistochemistry. Colorectal carcinoma cell lines were utilized to confirm the expression of Notch-1 in colorectal carcinoma cells. Lentiviral-encoding Notch-1-siRNA, as well as Notch-1 inhibitor was employed to silence Notch-1 expression and to inhibit Notch-1 activity in HT29 cells, respectively. As evidenced, Notch-1 and Jagged1 were highly expressed in colorectal carcinoma and colorectal adenoma tissues, compared with those in paracancerous tissue and normal colorectal tissue. However, the expression of Notch-1 and Jagged1 was comparable in colorectal carcinoma and colorectal adenoma tissues, and in paracancerous and normal colorectal tissues. After screening colorectal carcinoma cell lines, Notch-1 was extensively expressed in COLO 205, HT29, SW480 and SW1116 cells, but slightly expressed in LoVo cells. Subsequently, HT29 cell line was selected to investigate the roles of Notch-1 in tumor cell growth and apoptosis. Lenti-viral encoding Notch-1 siRNA significantly decreased Notch-1 expression, inhibited cell growth, arrested the cell cycle at G1 phase and promoted apoptosis. These effects were further confirmed by the Notch-1 inhibitor DAPT. Additionally, we evidenced that Notch-1 silence promoted P21 and PUMA expression in HT29 cells. Taken together, Notch-1 is an oncogene in colorectal carcinoma and the inhibition of Notch-1 could delay the cell growth and promote apoptosis in colorectal cancer.

Cytotoxic organometallic [Ru(η6-anethole)(en)(X)]PF6 (X = Br or I) complexes: Synthesis, characterization and in vitro biological evaluation

Two new organometallic compounds with the general formula [Ru(η6-anethole)(en)(X)]PF6, where X=Br (5) or I (6) and en=ethylenediamine, were synthesized and fully characterized using standard techniques (NMR, MS and elemental analysis). Displacement of the proton and carbon aromatic chemical shifts of anethole to the upper field in both compounds indicated organometallic Ru(η6-anethole) bond formation, and the characteristic “piano-stool” structure of these types of compounds was confirmed by the single crystal X-ray diffraction of compound 5. Compounds 5 and 6 exhibited interesting cytotoxicity, especially toward the human colon tumor cell line HT-29, similar to the previously studied compound [Ru(η6-anethole)(en)(Cl)]PF6 (4). A slight tendency toward cytotoxicity could be observed by varying the halogen leaving group (IC50 value): 6 (10±2μM)>5 (18±2μM)=4 (18±3μM). Compound 6 showed 3-fold more biological activity in HT-29 cells than toward the non-tumor colon cell line CCD-841, making it an interesting candidate for further studies and drug development.

Abstract 4066: The dihydroartemisinin oxime dimer (NSC735847) displays a selective toxicity in colon cancer cells which is potentially mediated by endoplasmic reticulum stress

Abstract Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in the United States. Common chemotherapeutic regimens for CRC include a combination of chemotherapeutic agents to produce synergistic drug activity and reduce adverse effects. However, adverse effects due to lack of selective toxicity is still a major problem with many chemotherapeutic agents. Novel drugs that display tumor selective toxicity are desperately needed. Several studies have shown that artemisinin monomers (Clinically used anti-malarial agent) possess antineoplastic activity with minimal toxicity. Interestingly, artemisinin dimers showed more potent antineoplastic activity compared to the monomers. However, few studies have fully characterized the activity of these molecules. In this study, we tested the antitumor activity of five chemically-synthesized dihydroartemisinin (DHA) dimers using the human colon cancer cell lines, HT29 and HCT116 and the non-tumorigenic colon cell line, FHC. Compared to other tested dimers, the DHA oxime dimer, NSC735847 showed pronounced selective toxicity in HT29 and HCT116 cells. Using MTS cell viability assays, NSC735847caused a preferential reduction in the viability of HT29 and HCT116 colon cancer cells compared to the non-tumorigenic FHC cells. In addition, NSC735847 significantly increased caspase 3/7 activity in HT29 and HCT116 cells but not in FHC cells which suggests that this compound causes selective apoptosis in these colon cancer cell lines. The combination of NSC735847 and the topoisomerase I inhibitor, irinotecan (commonly used chemotherapeutic agent for colorectal cancer) showed synergistic antitumor activity in HT29 cells. The combination of the two drugs caused a significant increase in cell death and caspase 3/7 activity which were greater than those caused by the individual drugs. Previous studies using other tumorigenic cell lines, suggested that NSC735847 induces oxidative and endoplasmic reticulum (ER) stress. To gain insight into the potential mechanisms of anti-colorectal cancer activity of NSC735847, we tested if this compound causes ER stress and/ or oxidative stress in HT29 cells and whether ER stress was required for NSC735847-induced apoptotic cell death. NSC735847 increased the expression of ER stress marker C/EBP homologous protein 10 (CHOP10) in HT29 cells and the use of ER stress inhibitor, salubrinal, significantly decreased NSC735847-induced cell death and apoptosis. Additionally, NSC735847 caused oxidative stress in HT29 cells which was inhibited by pretreatment of the cells with the antioxidant, trolox. The crosstalk between oxidative stress and ER stress in NSC735847-induced apoptosis in colon cancer cells is still under investigation. Our results suggest that NSC735847 causes ER stress in HT29 cells which plays a major role in drug-induced cell death and apoptosis in these cells. Citation Format: Ahmed E. Elhassanny, Eman Soliman, Paul McGuire, Mahmoud ElSohly, Waseem Gul, Rukiyah Van Dross. The dihydroartemisinin oxime dimer (NSC735847) displays a selective toxicity in colon cancer cells which is potentially mediated by endoplasmic reticulum stress [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4066. doi:10.1158/1538-7445.AM2017-4066

The anti-AChE and anti-proliferative Activities of Glaucium acutidentatum and Glaucium corniculatum Alkaloid Extracts

In this study, methanol and water extracts of Glaucium acutidentatum and Glaucium corniculatum were analysed for anti-AChE activity on neuronal PC12 cell and anti-proliferative activity on HT-29 and HeLa cancer cells. In this study, total alkaloid, phenol and flavonoid content were analyzed for the determination of active compounds of Glaucium acutidentatum and Glaucium corniculatum. Indeed, methanol and water alkaloid extracts of these plants were evaluated for their anti-AChE activities on NGF-differentiated PC12 cells (dPC12) and anti-proliferative activities on HT-29 and HeLa cancer cells. Our data showed that alkaloid was major compound, the different concentrations of plant extracts had 35-90% in vitro AChE inhibitory activity and 26-54% cellular AChE inhibitory activity and it is dose dependent manner. Furthermore, G. acutidentatum methanolic extracts showed the highest anti-proliferative activity in HT-29 cells (45±5%) Both 1000 μg/ml methanolic extracts showed the maximum anti-proliferative effect in HeLa cells (64±3%). In conclusion, this study has shown that the anti-AChE and anti-proliferative effects of these two plants and the presence of a new AChEi may be effective in AD and cancer.

Isoliquiritigenin inhibits TNF-α-induced release of high-mobility group box 1 through activation of HDAC in human intestinal epithelial HT-29 cells

The suppression of pro-inflammatory cytokine-induced inflammation responses is an attractive pharmacological target for the development of therapeutic strategies for inflammatory bowel disease (IBD). In the present study, we evaluated the anti-inflammatory properties of flavonoid isoliquiritigenin (ISL) in intestinal epithelial cells and determined its mechanism of action. ISL suppressed the expression of inflammatory molecules, including IL-8, IL-1β and COX-2, in TNF-α-stimulated HT-29 cells. Moreover, ISL induced activation of Nrf2 and expression of its target genes, such as HO-1 and NQO1. ISL also inhibited the TNF-α-induced NF-κB activation in HT-29 cells. High-mobility group box 1 (HMGB1), which is one of the critical mediators of inflammation, is actively secreted from inflammatory cytokine-stimulated immune or non-immune cells. ISL inhibited HMGB1 secretion by preventing TNF-α-stimulated HMGB1 relocation, whereas the RNA and protein expression levels of cellular HMGB1 did not change in response to TNF-α or ISL. Moreover, we found that HMGB1 acetylation was associated with HMGB1 translocation to the cytoplasm and the extracellular release in TNF-α-stimulated HT-29 cells; however, ISL significantly decreased the amount of acetylated HMGB1 in both the cytoplasm and extracellular space of HT-29 cells. Histone deacetylase (HDAC) inhibition by Scriptaid abrogated ISL-induced HDAC activity and reversed the ISL-mediated decrease in acetylated HMGB1 release in TNF-α-stimulated HT-29 cells, suggesting that, at least in TNF-α-stimulated HT-29 cells, ISL suppresses acetylated HMGB1 release via the induction of HDAC activity. Together, the current results suggest that inhibition of HMGB1 release via the induction of HDAC activity using ISL may be a promising therapeutic intervention for IBD.

Drug membrane transporters and CYP3A4 are affected by hypericin, hyperforin or aristoforin in colon adenocarcinoma cells.

Our previous results have shown that the combination of hypericin-mediated photodynamic therapy (HY-PDT) at sub-optimal dose with hyperforin (HP) (compounds of Hypericum sp.), or its stable derivative aristoforin (AR) stimulates generation of reactive oxygen species (ROS) leading to antitumour activity. This enhanced oxidative stress evoked the need for an explanation for HY accumulation in colon cancer cells pretreated with HP or AR. Generally, the therapeutic efficacy of chemotherapeutics is limited by drug resistance related to the overexpression of drug efflux transporters in tumour cells. Therefore, the impact of non-activated hypericin (HY), HY-PDT, HP and AR on cell membrane transporter systems (Multidrug resistance-associated protein 1-MRP1/ABCC1, Multidrug resistance-associated protein 2-MRP2/ABCC2, Breast cancer resistance protein - BCRP/ABCG2, P-glycoprotein-P-gp/ABCC1) and cytochrome P450 3A4 (CYP3A4) was evaluated. The different effects of the three compounds on their expression, protein level and activity was determined under specific PDT light (T0+, T6+) or dark conditions (T0- T6-). We found that HP or AR treatment affected the protein levels of MRP2 and P-gp, whereas HP decreased MRP2 and P-gp expression mostly in the T0+ and T6+ conditions, while AR decreased MRP2 in T0- and T6+. Moreover, HY-PDT treatment induced the expression of MRP1. Our data demonstrate that HP or AR treatment in light or dark PDT conditions had an inhibitory effect on the activity of individual membrane transport proteins and significantly decreased CYP3A4 activity in HT-29 cells. We found that HP or AR significantly affected intracellular accumulation of HY in HT-29 colon adenocarcinoma cells. These results suggest that HY, HP and AR might affect the efficiency of anti-cancer drugs, through interaction with membrane transporters and CYP3A4.

PKM2 Subcellular Localization Is Involved in Oxaliplatin Resistance Acquisition in HT29 Human Colorectal Cancer Cell Lines.

Chemoresistance is the main cause of treatment failure in advanced colorectal cancer (CRC). However, molecular mechanisms underlying this phenomenon remain to be elucidated. In a previous work we identified low levels of PKM2 as a putative oxaliplatin-resistance marker in HT29 CRC cell lines and also in patients. In order to assess how PKM2 influences oxaliplatin response in CRC cells, we silenced PKM2 using specific siRNAs in HT29, SW480 and HCT116 cells. MTT test demonstrated that PKM2 silencing induced resistance in HT29 and SW480 cells and sensitivity in HCT116 cells. Same experiments in isogenic HCT116 p53 null cells and double silencing of p53 and PKM2 in HT29 cells failed to show an influence of p53. By using trypan blue stain and FITC-Annexin V/PI tests we detected that PKM2 knockdown was associated with an increase in cell viability but not with a decrease in apoptosis activation in HT29 cells. Fluorescence microscopy revealed PKM2 nuclear translocation in response to oxaliplatin in HCT116 and HT29 cells but not in OXA-resistant HTOXAR3 cells. Finally, by using a qPCR Array we demonstrated that oxaliplatin and PKM2 silencing altered cell death gene expression patterns including those of BMF, which was significantly increased in HT29 cells in response to oxaliplatin, in a dose and time-dependent manner, but not in siPKM2-HT29 and HTOXAR3 cells. BMF gene silencing in HT29 cells lead to a decrease in oxaliplatin-induced cell death. In conclusion, our data report new non-glycolytic roles of PKM2 in response to genotoxic damage and proposes BMF as a possible target gene of PKM2 to be involved in oxaliplatin response and resistance in CRC cells.

Antioxidant, anti-inflammatory and anticarcinogenic activities of edible red oak (Quercus spp.) infusions in rat colon carcinogenesis induced by 1,2-dimethylhydrazine

Red oak (Quercus spp.) leaves are traditionally used as food in Mexico, and some of their infusions have potential anticarcinogenic and anti-inflammatory effects; however, these properties have not yet been scientifically tested. The aim of this work was to explore the anti-inflammatory activity in HT-29 cells and anticarcinogenic effect in 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis of red oak infusions. Quercus infusions were prepared and administered as the sole source of drink to male Sprague-Dawley rats (1% w/v) for the entire 26-week experimental period. On week 4, rats received 8 subcutaneous injections of DMH (21 mg/kg body weight) once a week. The results showed that mean tumor (0.9 ± 0.2 vs. 2.6 ± 0.3) and multiplicity (1.2 ± 0.1 vs. 2.0 ± 0.23), and β-catenin protein level (2.2-fold) in adenocarcinomas were significantly lower in Quercus sideroxyla-treated group compared with DMH group. By contrast, Quercus durifolia and Quercus eduardii infusions had no protective effect. Additionally, the experiments in HT-29 cells confirmed that Q. sideroxyla infusion effectively decreased the levels of the inflammatory markers COX-2 and IL-8 by modulating the expression of NF-κB. These results highlight some of the molecular mechanisms related to the chemopreventive effect of Q. sideroxyla infusion and its potential value as a source of bioactive compounds.

Effect of Cnidii Rhizoma on nitric oxide production and invasion of human colorectal adenocarcinoma HT-29 cells.

Colorectal adenocarcinoma is the most common type of gastrointestinal cancer. Colon adenocarcinoma is a major health problem worldwide due to the high prevalence and mortality rates associated with the disease. The majority of colorectal carcinomas are adenocarcinomas, which originate from the epithelial cells of the colorectal mucosa. HT-29 cells, which originate from human colon adenocarcinoma, are used as an in vitro model to investigate the effect of malignant transformation on the expression of cellular constituents and functions of the intestinal epithelium. Nitric oxide (NO) is a signaling molecule, which is involved in inflammation and carcinogenesis. It has been reported that enhanced inducible NO synthase (iNOS) activity and the resulting NO concentrations in human colon carcinoma contribute to tumor progression and vascular invasion. The present study investigates the effect of pro-inflammatory cytokine-induced nitric oxide (NO) production and iNOS expression on the invasion of human colorectal adenocarcinoma HT-29 cells, and the effect of extract from Cnidii Rhizoma on NO production and the invasiveness of HT-29 cells. Treatment of HT-29 cells with cytokines, 100 U/ml interferon γ, 10 ng/ml interleukin-1 α and 25 ng/ml tumor necrosis factor α was found to increase NO production. Pretreatment of the cells with Cnidii Rhizoma (0.1–5 mg/ml) resulted in an inhibition of cytokine-induced NO production and iNOS expression. The invasiveness of HT-29 cells through Matrigel was significantly increased by treatment with cytokines. Cnidii Rhizoma inhibited the invasiveness of cytokine-treated HT-29 cells through the Matrigel-coated membrane in a concentration-dependent manner. Matrix metalloproteinase (MMP) activity in HT-29 cells increased following the treatment with cytokines, and pretreatment of the cells with Cnidii Rhizoma inhibited cytokine-induced MMP-2 activity. These results provide sufficient information for the further development of Cnidii Rhizoma as an antitumor metastatic agent for the treatment of colon cancer.