HT-29 Human Colorectal Cancer Cells Research Articles

MRI assessment of glutamine uptake correlates with the distribution of glutamine transporters and cancer stem cell markers

Glutamine provides carbon and nitrogen for macromolecular synthesis and participates in adenosine triphosphate (ATP) generation, anabolic metabolism, redox homeostasis, cell signaling, and cancer stem cell (CSC) metabolism. New treatment strategies targeting glutamine metabolism in cancer have emerged recently. We previously reported the magnetic resonance imaging (MRI) assessment of glutamine uptake by tumors and activated glutamine metabolism in CSC. In the present study, using MRI, we determined the correlation between glutamine uptake and the distribution of glutamine transporters, namely ASCT2 and SLC38A2 (SNAT2), glutaminase (GLS), and CSC markers, such as CD44 and CD166, in a mouse xenograft model of HT29 human colorectal cancer cells. MRI data revealed an obvious change in intensity following glutamine administration. Immunohistochemistry (IHC) results indicated that ASCT2 staining was stronger in regions that exhibited high glutamine uptake (p = 0.0079). Significant differences were found in the IHC staining intensities of SNAT2, GLS, and CSC markers in the areas of high and low glutamine uptake (p = 0.0079, p = 0.0159 and p = 0.0079, respectively). We also investigated the effect of an ASCT2 inhibitor on the uptake of glutamine using MRI. A statistically significant difference in the initial glutamine uptake was found after ASCT2 inhibitor administration. To conclude, glutamine uptake is positively correlated with the distribution of ASCT2 and certain CSC markers.

Suppressive GLI2 fragment enhances liver metastasis in colorectal cancer.

Linoleic acid (LA) has been shown to cause inflammation and promote development of colorectal cancer (CRC). Moreover, many literatures show that LA is associated with cancer metastasis. Metastatic cancer cells have high stemness, suggesting that LA might affect the stemness of cancer cells. In this study, we examined the effect of LA on the hedgehog system, which affects cancer stemness. In CT26 cells, LA treatment induced the expression of sonic hedgehog (Shh); the signal transduction factor, and glioma-associated oncogene homolog (Gli) 2, whereas the expression of SRY-box transcription factor (Sox) 17 was suppressed. Furthermore, LA reduced GLI2 ubiquitination, resulting in an increase in the N-terminal fragment of GLI2, known as suppressive GLI2, produced by cleavage of GLI2. LA-induced cleaved GLI2 was also detected in Colo320 and HT29 human CRC cells. Knocking down Gli2 abrogated the LA-mediated suppression of Sox17 expression. These results suggest that LA promotes tumor cell stemness by increasing of suppressive GLI2 fragments via GLI2 modification. In mouse liver metastasis models, LA enhanced metastasis with production of the suppressive GLI2 fragments in CT26 and HT29 cells, whereas knockdown of GLI2 abrogated LA-induced metastatic activity. In human CRCs, the cases with liver metastasis showed the suppressive GLI2 fragments. This study provides mechanistic insights into LA-induced stemness in colon cancer cells. This finding suggests that dietary intake of LA might increase the stemness of cancer cells and enhance metastatic activity of the cancer.

Granatin B and punicalagin from Chinese herbal medicine pomegranate peels elicit reactive oxygen species-mediated apoptosis and cell cycle arrest in colorectal cancer cells

BackgroundColorectal cancer ranks among the most common cancers. 5-Fluorouracil (5-FU) based first-line chemotherapy for colorectal cancer treatment often leads to chemoresistance and gastrointestinal mucositis. PurposeThis study aimed to find potential therapeutic agents from herbal medicine with anti-colorectal cancer and anti-mucositis activities. MethodsChinese medicine theory, network pharmacology analyses, and antioxidant activity coupled with liquid chromatography tandem mass spectrometry analyses were used to identify potential bioactive compounds. HT-29 human colorectal cancer cell culture and xenograft tumor models were employed to study anti-colorectal cancer efficacy. Lipopolysaccharide-induced RAW 264.7 and 5-FU treated Dark Agouti rats were used to evaluate anti-inflammatory and anti-mucositis activities. Histological staining, immunofluorescence imaging, western blots, and flow cytometric analyses were employed to explore the underlying mechanisms. ResultsBoth Chinese medicine theory and network pharmacology analyses indicated pomegranate peels as a potential anti-colorectal cancer and anti-mucositis agent. Antioxidant activity coupled with liquid chromatography tandem mass spectrometry analyses revealed granatin B and punicalagin as the most potent antioxidant compounds in pomegranate peels. Granatin B and punicalagin demonstrated superior anti-colorectal cancer activities in both cell culture and xenograft tumor models. Granatin B and punicalagin also exhibited strong anti-inflammatory activities in lipopolysaccharide-induced RAW264.7 cells and anti-mucositis activities in 5-FU-treated rats. Mechanistic studies revealed that granatin B and punicalagin induced reactive oxygen species-mediated S-phase cell cycle arrest and apoptosis in HT-29 cells. Moreover, these compounds sensitized HT-29 cells to 5-FU-induced cell death and S-phase cell cycle arrest. ConclusionWe report that granatin B and punicalagin exhibit superior anti-colorectal cancer and anti-mucositis activities. To the best of our knowledge, these results are novel and suggest that utilizing phenols from herbal medicine, such as granatin B and punicalagin, to target reactive oxygen species may be an innovative therapy to treat colorectal cancer and intestinal mucositis.

Effects of octacosanol on HMG-CoA reductase and cyclooxygenase-2 activities in the HT-29 human colorectal cancer cell line

Effects of octacosanol on HMG-CoA reductase and cyclooxygenase-2 activities in the HT-29 human colorectal cancer cell line

The Class I HDAC Inhibitor, MS-275, Prevents Oxaliplatin-Induced Chronic Neuropathy and Potentiates Its Antiproliferative Activity in Mice.

Oxaliplatin, the first-line chemotherapeutic agent against colorectal cancer (CRC), induces peripheral neuropathies, which can lead to dose limitation and treatment discontinuation. Downregulation of potassium channels, which involves histone deacetylase (HDAC) activity, has been identified as an important tuner of acute oxaliplatin-induced hypersensitivity. MS-275, a class I histone deacetylase inhibitor (HDACi), prevents acute oxaliplatin-induced peripheral neuropathy (OIPN). Moreover, MS-275 exerts anti-tumor activity in several types of cancers, including CRC. We thus hypothesized that MS-275 could exert both a preventive effect against OIPN and potentially a synergistic effect combined with oxaliplatin against CRC development. We first used RNAseq to assess transcriptional changes occurring in DRG neurons from mice treated by repeated injection of oxaliplatin. Moreover, we assessed the effects of MS-275 on chronic oxaliplatin-induced peripheral neuropathy development in vivo on APCMin/+ mice and on cancer progression when combined with oxaliplatin, both in vivo on APCMin/+ mice and in a mouse model of an orthotopic allograft of the CT26 cell line as well as in vitro in T84 and HT29 human CRC cell lines. We found 741 differentially expressed genes (DEGs) between oxaliplatin- and vehicle-treated animals. While acute OIPN is known as a channelopathy involving HDAC activity, chronic OIPN exerts weak ion channel transcriptional changes and no HDAC expression changes in peripheral neurons from OIPN mice. However, MS-275 prevents the development of sensory neuropathic symptoms induced by repeated oxaliplatin administration in APCMin/+ mice. Moreover, combined with oxaliplatin, MS-275 also exerts synergistic antiproliferative and increased survival effects in CT26-bearing mice. Consistently, combined drug associations exert synergic apoptotic and cell death effects in both T84 and HT29 human CRC cell lines. Our results strongly suggest combining oxaliplatin and MS-275 administration in CRC patients in order to potentiate the antiproliferative action of chemotherapy, while preventing its neurotoxic effect.

Treatment of HT29 Human Colorectal Cancer Cell Line with Nanocarrier-Encapsulated Camptothecin Reveals Histone Modifier Genes in the Wnt Signaling Pathway as Important Molecular Cues for Colon Cancer Targeting.

Cancer cells are able to proliferate in an unregulated manner. There are several mechanisms involved that propel such neoplastic transformations. One of these processes involves bypassing cell death through changes in gene expression and, consequently, cell growth. This involves a complex epigenetic interaction within the cell, which drives it towards oncogenic transformations. These epigenetic events augment cellular growth by potentially altering chromatin structures and influencing key gene expressions. Therapeutic mechanisms have been developed to combat this by taking advantage of the underlying oncogenic mechanisms through chemical modulation. Camptothecin (CPT) is an example of this type of drug. It is a selective topoisomerase I inhibitor that is effective against many cancers, such as colorectal cancer. Previously, we successfully formulated a magnetic nanocarrier-conjugated CPT with β-cyclodextrin and iron NPs (Fe3O4) cross-linked using EDTA (CPT-CEF). Compared to CPT alone, it boasts higher efficacy due to its selective targeting and increased solubility. In this study, we treated HT29 colon cancer cells with CPT-CEF and attempted to investigate the cytotoxic effects of the formulation through an epigenetic perspective. By using RNA-Seq, several differentially expressed genes were obtained (p < 0.05). Enrichr was then used for the over-representation analysis, and the genes were compared to the epigenetic roadmap and histone modification database. The results showed that the DEGs had a high correlation with epigenetic modifications involving histone H3 acetylation. Furthermore, a subset of these genes was shown to be associated with the Wnt/β-catenin signaling pathway, which is highly upregulated in a large number of cancer cells. These genes could be investigated as downstream therapeutic targets against the uncontrolled proliferation of cancer cells. Further interaction analysis of the identified genes with the key genes of the Wnt/β-catenin signaling pathway in colorectal cancer identified the direct interactors and a few transcription regulators. Further analysis in cBioPortal confirmed their genetic alterations and their distribution across patient samples. Thus, the findings of this study reveal that colorectal cancer could be reversed by treatment with the CPT-CEF nanoparticle-conjugated nanocarrier through an epigenetic mechanism.

Nannocystin ax, an eEF1A inhibitor, induces G1 cell cycle arrest and caspase-independent apoptosis through cyclin D1 downregulation in colon cancer in vivo

Colorectal cancer (CRC) is one of the most common causes of cancer-related death worldwide. Nannocystin ax (NAN), a 21-membered cyclodepsipeptide initially isolated from myxobacteria of the Nannocystis genus, was found to target the eukaryotic elongation factor 1A (eEF1A). The current study was designed to evaluate the anticancer effect and underlying mechanisms of NAN with in vitro and in vivo models. Results showed that NAN induced G1 phase cell cycle arrest and caspase-independent apoptosis in HCT116 and HT29 human CRC cells. NAN significantly downregulated cyclin D1 level in a short time, but NAN did not affect the transcription level and ubiquitin-dependent degradation of cyclin D1. Furthermore, NAN treatment directly targeted eEF1A and partially decreased the synthesis of new proteins, contributing to the downregulation of cyclin D1. Besides, NAN significantly suppressed tumor growth in the zebrafish xenograft model. In conclusion, NAN triggered G1 phase cell cycle arrest through cyclin D1 downregulation and eEF1A-targeted translation inhibition and promoted caspase-independent apoptosis in CRC cells.

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.

Sildenafil Induces Cell Cycle Arrest and Apoptosis in Human Colorectal Cancer HT-29 Cells

Phosphodiesterase is an enzyme that degrades the phosphodiester bond in the second messenger molecules cAMP and cGMP, and regulates the localization, duration, and amplitude of cyclic nucleotide signaling within subcellular domains. Sildenafil is a potent and selective inhibitor of the type 5 cGMP-specific phosphodiesterase used clinically to treat erectile dysfunction and pulmonary arterial hypertension. In this study, we examined the effect of sildenafil on human colorectal cancer HT-29 cells. Our data showed that sildenafil induced cell cycle arrest and apoptosis, and cotreatment with a ROS scavenger N-acetyl-L-cysteine partially reversed cell apoptosis caused by sildenafil in human colorectal cancer HT-29 cells. Overall, our study suggests that sildenafil appears to be a promising new treatment option for colorectal cancer.

Establishment of an In Vivo Xenograft Mouse Model of a Subcutaneous Submillimeter HT-29 Tumor Formed from a Single Spheroid Transplanted Using Radiation-Crosslinked Gelatin Hydrogel Microwell

Colorectal cancer is a frequent cause of death worldwide. The detection and treatment of small nodules are crucial for improving survival of colorectal cancer patients. Submillimeter tumors are useful tools for developing novel methods to approach this issue. However, there are no suitable in vivo models that allow easy monitoring of the growth of these tumors. This study established a xenograft mouse model of subcutaneous submillimeter tumors with human colorectal cancer HT-29 cells. We transplanted a single spheroid formed by HT-29 cells expressing red fluorescent protein (RFP) (HT-29-RFP). Additionally, we adopted our newly developed radiation-crosslinked gelatin hydrogel microwells (rGHMs), which can be used as a culture base to form spheroids and as a transplantation scaffold with biocompatibility and biodegradability. Spheroids approximately 700 μm in size were uniformly created in seven days in the respective rGHMs. Every single spheroid was extracted either with or without rGHM and transplanted into the subcutis of severe combined immunodeficiency (SCID) mice (n = 4). After 21 days, the spheroids inoculated together with rGHM successfully formed uniform subcutaneous submillimeter tumor xenografts that were observable in vivo in a stereoscopic fluorescence microscope in all transplanted mice. In contrast, spheroids transplanted without rGHM also developed small tumors in all mice but showed higher variability in size than those transplanted with rGHM. During transplantation, the rGHM ensured easy handling and stabilization of the position of a single spheroid. Inoculation of spheroids with rGHM in the nude mice was similarly examined (n = 4), showing that only one out of four mice formed tumors. In conclusion, rGHM effectively formed spheroids and created uniformed xenografted submillimeter tumors of HT-29-RFP in SCID mice. Our model could provide a useful platform to develop medicines and methods for detection and treatment of small nodules of colorectal cancer.

Quercetin and Luteolin Improve the Anticancer Effects of 5-Fluorouracil in Human Colorectal Adenocarcinoma In Vitro Model: A Mechanistic Insight

The aim of this study was to investigate the antitumor effects of quercetin and luteolin combined with 5-Fluorouracil (5-FU) in HT-29 human colorectal cancer cells. Cell viability induced by quercetin, luteolin and combination of these compounds with 5-FU were determined by MTT assay, also Cell death detection Elisa assay and fluorescence microscopy were performed to investigate apoptotic effects. Hu-VEGF Elisa assay was employed to determine the effects of treatments on angiogenesis. Western blot and qRT-PCR analysis were performed to investigate effects on p53, Bax, Bcl-2, p38 MAPK, mTOR, PTEN, and Akt proteins and genes. The results indicated that quercetin, luteolin and combinations of these compounds with 5-FU inhibited the growth of HT 29 cells. Compared to the control, apoptosis were triggered 8.1 and 10.1 fold in HT-29 cells, that treated with quercetin + 5-FU and luteolin + 5-FU, respectively. VEGF amount significantly decreased by combined treatments. qRT-PCR and western blot results demonstrated that quercetin, luteolin and the combinations of these flavonoids with 5-FU, modulate the apoptotic pathways in HT-29 cells. The increase in p53, Bax, p38 MAPK, and PTEN gene expression levels compared to the control group was 1.71, 1.42, 3.26, and 3.29-fold with 5-FU + L treatment, respectively, while this increase was 8.43, 1.65, 3.55, and 3.54-fold with 5-FU + Q treatment, respectively. In addition, when the anti-apoptotic Bcl-2, mTOR, and Akt gene expression levels were normalized as 1 in the control group, they were 0.28, 0.41, and 0.22 with 5-FU + L treatment, and 0.32, 0.46, and 0.39, respectively, with 5-FU + Q treatment. These findings suggested that quercetin and luteolin synergistically enhanced the anticancer effect of 5-FU in HT 29 cells and may therefore minimize the toxic effects of 5-FU in the clinical treatment of colorectal cancer.

In vivo and in vitro Experiment of E74-Like Factor 5 Overexpression Inhibiting the Biological Behavior of Colon Cancer Cells

To investigate the effect of E74-like factor 5 (ELF5) overexpression on the growth and invasion ability of colorectal cancer cells and its effect on tumor formation in nude mice. Human colorectal cancer SW480 and HT-29 cells were divided into 5 groups: the lentivirus (LV)- GFP group transfected with empty vector LV- GFP, the LV- ELF5 group transfected with recombinant LV- ELF5, the shRNA-NC group transfected with empty vector shRNA-NC, the shRNA- ELF5 group transfected with recombinant shRNA- ELF5, and the control group, not transfected with any vector. Seventy-two h after transfection, the cell supernatant containing lentivirus was collected. The mRNA expression level of ELF5 in each group was examined by real-time fluorescent quantitative PCR (RT-qPCR). The protein expression levels of ELF5, apoptosis-related cleaved Caspase-3/Caspase-3 and cleaved Caspase-9/Caspase-9, and invasion-related E-cadherin and N-cadherin were checked with Western blot. CCK-8 was used to check cell viability. Colony formation experiment was done to evaluate colony formation rate. Flow cytometry was used to assess cell apoptosis. Transwell migration assay was used to examine cell invasion. TUNEL assay was used to examine the apoptosis of tissues cells. Immunohistochemistry test was done to determine the expression of E-cadherin and N-cadherin in tissues. 20 BALB/c nude mice were put into 4 groups (5 in each group): LV- GFP group, shRNA-NC group, LV- ELF5 group, and shRNA- ELF5 group. Recombinant lentiviral SW480 cell supernatants were subcutaneously injected into nude mice to construct nude mice tumorigenesis models and the volume changes of transplanted tumors were monitored. On the 30th day, transplanted tumor tissues from the nude mice were extracted and the tumor mass was measured. Western blot was done to measure the expression of ELF4 protein in the transplanted tumors. TUNEL staining was used to check cell apoptosis in the tissues, and the positive expression of N-cadherin in the transplanted tumor was measured by immunohistochemical tests. Compared with the control group, there was no statistically significant difference in the indicators of the two cell lines in the LV- GFP group and shRNA-NC group. The results of Western blot and RT-qPCR showed that the ELF5 protein and mRNA of the LV- ELF5 group of the two cell lines were up-regulated ( P<0.05, compared with those of the LV- GFP group), and the ELF5 protein and mRNA of the shRNA- ELF5 group were down-regulated ( P<0.05). The ELF5 overexpression system and interference system were successfully constructed. Compared with the LV- GFP group, data from the LV- ELF5 group showed that cell viability and colony formation rate ( P<0.05) were reduced, SW480 and HT-29 cell apoptosis was promoted, cleaved Caspase-3/Caspase-3 and cleaved Caspase-9/Caspase-9 protein expression was up-regulated ( P<0.05), cell invasion was inhibited, and the expression of E-cadherin protein was up-regulated while the expression of N-cadherin protein was down-regulated ( P<0.05). After ELF5 interference, the above-mentioned expression of cells demonstrated an opposite trend ( P<0.05, comparing shRNA- ELF5 group with shRNA-NC group). In vivo experimental results indicated that ELF5 overexpression reduced tumor volume and tumor mass ( P<0.05), promoted cell apoptosis in tissues ( P<0.05), and inhibited N-cadherin protein expression ( P<0.05). When ELF5 expression was inhibited, the above mentioned experimental results showed the opposite trend. In vivo and in vitro experiments showed that ELF5 overexpression could promote the apoptosis of colorectal cancer cells and inhibit the growth and invasion of colorectal cancer cells.

Effect of the polysaccharides derived from Dendrobium officinale stems on human HT-29 colorectal cancer cells and a zebrafish model

Human colorectal cancer (CRC) is treated with 5-fluorouracil (5-Fu). However, this drug causes various adverse effects, suggesting the benefit of developing safer natural-based drugs with high specificity and tolerable adverse effects. Dendrobium officinale has been used as a functional food and important medicine in China for more than a thousand years. The natural polysaccharides obtained from D. officinale (DOPW-1) show inhibitory activity against cancer cells. This study aimed to comparatively investigate the anticancer activity of DOPW-1 and mannose (Mann) on HT-29 cells and explored the possible underlying molecular mechanisms of CRC treatment. HT-29 cells were treated with 5-Fu, DOPW-1, and Mann or their combinations. Cell viability and apoptosis were examined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Hoechst 33342 with annexin V-fluorescein isothiocyanate/propidium iodide assays, respectively. DOPW-1 showed good antitumor effects on HT-29 cells and significantly potentiated the anticancer activities of 5-Fu in vitro and in vivo. DOPW-1 significantly inhibited tumor metastasis in the zebrafish model. Furthermore, the monosaccharide composition of DOPW-1 might not have an important effect on its antitumor activity. The results of Western blot analysis suggested that DOPW-1 alone and in combination with 5-Fu induced cell apoptosis using the mitochondria-dependent intrinsic apoptotic pathway. Thus, DOPW-1 is a potential source of natural polysaccharides for CRC therapy alone or in combination with 5-Fu.

Comprehensive Analysis of microRNA Profiles in Organoids Derived from Human Colorectal Adenoma and Cancer

Introduction: Exosomes are membrane-enclosed nanovesicles, which are increasingly being recognized as important cell communication components for their role in transmitting microRNAs (miRNAs). No previous study has addressed the exosomal miRNA profile in colorectal adenomas (CRAs) because the long-term culture of CRA is challenging. This study aimed to identify the miRNA signature in organoid exosomes derived from human CRA and colorectal cancer (CRC) samples. Methods: Organoid cultures were developed from resected colorectal tissues of patients with CRA or CRC undergoing surgery or endoscopic mucosal resection. Exosomes were prepared from the conditioned medium of the organoids. miRNAs were prepared from the exosomes and their source organoids. The miRNA expression profiles were compared using microarray analysis. The impact of alteration of miRNA expression on cell proliferation was examined using miRNA mimics or inhibitors in HT-29 human CRC cells. Results: We established 6 organoid lines from CRC and 8 organoid lines from CRA. Exosomal miRNA signatures were different between the organoids derived from CRA and CRC. Both exosomal and cellular miR-1246 expressions were upregulated in CRC-derived organoids compared to their expression in CRA-derived organoids. Alteration of miR-1246 expression by the miR-1246 mimic or inhibitor increased or decreased cell proliferation in HT-29 cells, respectively. Conclusions: We report for the first time the miRNA profiles of exosomes in CRA- and CRC-derived organoids. The upregulation of miR-1246 might play a role in increased cell proliferation in the process of CRA-carcinoma transition.

Structure-based Discovery of Cell-Potent Peptidomimetic Inhibitors for Protein N-Terminal Methyltransferase 1.

Protein N-terminal methyltransferases (NTMTs) catalyze the methylation of the α-N-terminal amines of proteins starting with an X-P-K/R motif. NTMT1 has been implicated in various cancers and in aging, implying its role as a potential therapeutic target. Through structural modifications of a lead NTMT1 inhibitor, BM30, we designed and synthesized a diverse set of inhibitors to probe the NTMT1 active site. The incorporation of a naphthyl group at the N-terminal region and an ortho-aminobenzoic amide at the C-terminal region of BM30 generates the top cell-potent inhibitor DC541, demonstrating increased activity on both purified NTMT1 (IC50 of 0.34 ± 0.02 μM) and the cellular α-N-terminal methylation level of regulator of chromosome condensation 1 (RCC1, IC50 value of 30 μM) in human colorectal cancer HT29 cells. Furthermore, DC541 exhibits over 300-fold selectivity to several methyltransferases. This study points out the direction for the development of more cell-potent inhibitors for NTMT1.

Glucosinolate-rich hydrolyzed extract from Moringa oleifera leaves decreased the production of TNF-α and IL-1β cytokines and induced ROS and apoptosis in human colon cancer cells

The objective was to characterize the phytochemical profile of Moringa oleifera leaves extracts (aqueous, AE; methanolic, ME; glucosinolates, GE; and glucosinolate-rich hydrolyzed, GEH) and comparatively evaluate their antiproliferative effect on HCT116 and HT-29 human colorectal cancer cells. Moringa extracts were composed of chlorogenic acid, quercetin glucoside, quercetin-malonyl-glucoside, and glucomoringin. IC50 values ranged from 0.17 to 3.17 mg/mL, suggesting that moringa leaves extracts exhibited antiproliferative effects on colon cancer cells. GEH decreased the production of pro-inflammatory cytokines (TNF-α, IL-1β). GEH increased apoptosis up to 58.1% in HCT116 (IC50: 0.55 mg/mL) and 38% in HT-29 (IC50: 0.59 mg/mL). GEH increased ROS LDH activity, and induced the expression of markers of apoptosis such as Bax (HCT116: 41%; HT-29: 52%) and Cyt c (HCT116:70%; HT-29:59%), while decreasing Bcl-2 (HCT116: 58%; HT-29: 43%) compared to untreated cells (p < 0.05). GEH can inhibit colon cancer cell proliferation through promoting apoptosis by ROS-mediated mitochondrial-dependent pathway.

Novel SIRT Inhibitor, MHY2256, Induces Cell Cycle Arrest, Apoptosis, and Autophagic Cell Death in HCT116 Human Colorectal Cancer Cells.

We examined the anticancer effects of a novel sirtuin inhibitor, MHY2256, on HCT116 human colorectal cancer cells to investigate its underlying molecular mechanisms. MHY2256 significantly suppressed the activity of sirtuin 1 and expression levels of sirtuin 1/2 and stimulated acetylation of forkhead box O1, which is a target protein of sirtuin 1. Treatment with MHY2256 inhibited the growth of the HCT116 (TP53 wild-type), HT-29 (TP53 mutant), and DLD-1 (TP53 mutant) human colorectal cancer cell lines. In addition, MHY2256 induced G0/G1 phase arrest of the cell cycle progression, which was accompanied by the reduction of cyclin D1 and cyclin E and the decrease of cyclin-dependent kinase 2, cyclin-dependent kinase 4, cyclin-dependent kinase 6, phosphorylated retinoblastoma protein, and E2F transcription factor 1. Apoptosis induction was shown by DNA fragmentation and increase in late apoptosis, which were detected using flow cytometric analysis. MHY2256 downregulated expression levels of procaspase-8, -9, and -3 and led to subsequent poly(ADP-ribose) polymerase cleavage. MHY2256-induced apoptosis was involved in the activation of caspase-8, -9, and -3 and was prevented by pretreatment with Z-VAD-FMK, a pan-caspase inhibitor. Furthermore, the autophagic effects of MHY2256 were observed as cytoplasmic vacuolation, green fluorescent protein-light-chain 3 punctate dots, accumulation of acidic vesicular organelles, and upregulated expression level of light-chain 3-II. Taken together, these results suggest that MHY2256 could be a potential novel sirtuin inhibitor for the chemoprevention or treatment of colorectal cancer or both.

Biological activities of siRNA-loaded lanthanum phosphate nanoparticles on colorectal cancer

Lanthanum can reduce absorption of phosphate by forming lanthanum phosphate complexes after oral administration of lanthanum carbonate tablets (FOSRENOL®) in patients. Based on the pH-responsive interaction of phosphate and lanthanum ions, the chitosan coated siRNA-loaded lanthanum phosphate nanoparticles (CS/LaP/siRNA NPs) were prepared for improving cancer treatment, in which polysaccharide chitosan was used as the outer shell to control the excessive growth of lanthanum phosphate complexes, and enable intestinal mucoadhesion. The CS/LaP/siEGFR NPs exhibited significant biological activities in human colorectal cancer HT-29 cells by the synergistic effects of siEGFRs and lanthanum ions, such as downregulation of EGFR and upregulation of miR-34a. Furthermore, significant tumor growth inhibition was observed in both transgenic C57BL/6-ApcMinC/Nju cancer mouse model and AOM/DSS chemically induced orthotopic colorectal cancer mouse model after intestinal instillation administration of CS/LaP/siEGFR NPs. Therefore, the lanthanum-based siRNA delivery system would provide a potential and efficient strategy for the treatment of colorectal cancers.

α-Linolenic and γ-linolenic acids exercise differential antitumor effects on HT-29 human colorectal cancer cells.

α-Linolenic acid (ALA, 18:3n-3) and γ-gamma linolenic acid (GLA, 18:3n-6) are polyunsaturated fatty acids (PUFA) that improve the human health. The present study focused on testing the in vitro antitumor actions of pure ALA and GLA on the HT-29 human colorectal cancer cell line. Cell viability was checked by MTT ((3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test, cell membrane damage by the lactate dehydrogenase assay, apoptosis was tested by both caspase-3 activity trial and transmission electron microscopy images, and protein composition was analyzed by quantitative proteomics analysis. MTT test revealed IC50 values of 230 and 255μM for ALA and GLA, respectively, at 72h. After 24h of incubation, both ALA and GLA induced apoptosis on HT-29 colorectal cancer cells according to the caspase-3 assay and microscopy images. SWATH/MS analysis evidenced that ALA significantly affected the mitochondrial protein import pathway and the citric acid cycle pathway, while GLA did not significantly affect any particular pathway. In summary, both ALA and GLA showed concentration-dependent inhibitory effects on HT-29 cells viability and induced cell death by apoptosis. ALA significantly affected cellular pathways, while GLA does not have specific actions on either pathway. Both n-3 and n-6 C18 PUFA are bioactive food components useful in the colorectal cancer prevention.

Studies on Apoptosis and Mechanism of Curcumin Chitosan Induced Human Colon Cancer Cells in Colorectal Cancer

To explore the function of curcumin chitosan on the proliferation of human colorectal cancer HT29 cells and to explore its effect on apoptosis. We applied MTT assay to test the inhibitory effect of curcumin chitosan on the proliferation of HT29 cells. The alterations of colorectal cancer cell morphology were observed by optical microscope and electron microscope. The change of early apoptosis rate was determined by flow cytometry using Annexin-V/PI double staining. By Comparison with the control group, curcumin chitosan significantly suppressed the cell proliferation and promoted cell apoptosis of HT29 cells in not only dose- but also time-dependent manner; through light microscopy and electron microscopy, the cell volume was reduced, the cell membrane was shrunk, chromatin was significantly concentrated. Typical apoptotic features such as aggregation; flow cytometry confirmed a significant increase in apoptotic rates (p &lt; 0 05).