Human Colorectal Cell Line HT-29 Research Articles

Docosahexaenoic acid may inhibit immune evasion of colorectal cancer cells through targeting immune checkpoint and immunomodulator genes and their controlling microRNAs.

Colorectal cancer is one of the major concerns in both developed and developing societies. Because of the serious side effects of the current treatments, novel therapy agents have been developed that target immune checkpoint and immunomodulatory molecules in the tumor environment. Therefore, this study investigates the effect of docosahexaenoic acid (DHA) fatty acid on the expression of immune checkpoint molecule, PD-L1, and immunomodulatory molecules, CD47 and CD39, and their controlling miRNAs in the colorectal cancer cell lines. Human colorectal cell lines HT-29 and Caco-2 were treated with 100 μM DHA and 50 μM LA for 24 h under the normoxic and hypoxic conditions. Total RNA was extracted and the qRT-PCR was performed to analyze the expression of the studied genes and miRNAs. The western blotting technique was also used for validation. The qRT-PCR results showed that DHA treatment decreased the expression of the PD-L1, CD47, and CD39 genes, but decreases these genes controlling miRNAs, mir-424, mir-133a, and mir-142, respectively. Western blotting analysis demonstrated that PD-L1 protein expression decreased after DHA treatment. LA administration had no inhibitory effect on the studied genes. This study showed that DHA may have anti-cancer properties by downregulation of proteins involved in the immune evasion of colorectal tumors. DHA could be used as a potential immune checkpoint inhibitor for the treatment of colorectal cancers.

Antibacterial, Antiviral, Antioxidant and Antiproliferative Activities of Thymus guyonii Essential Oil

The aerial parts of Thymus guyonii were hydrodistilled in a Clevenger type apparatus and analyzed by GC and GC-MS. 26 components were identified representing 99.8%, with carvacrol (55.6%), thymol (21.2%), o-cymene (9.7%) and δ-terpinene (5.7%) as the major components. T. guyonii essential oil exhibited a good bactericidal effect (MBC/MIC ratio = 2) against all the tested pathogenic bacteria. The essential oil lacks antiviral activity towards coxsackievirus B3 however it showed a good DPPH radical scavenging at 0.5 and 5 mg/mL test-concentrations (15.5±1.2% and 44.3±1.95%, respectively). The essential oil exhibited a proliferation inhibition of Human colorectal cell line HT-29 (30.4±3.4%) at 50 μg/mL test-concentration.

β-Asarone induces senescence in colorectal cancer cells by inducing lamin B1 expression

Colorectal cancer is a leading cause of cancer mortality with a complex carcinogenesis that includes reduced cellular senescence. Lamin proteins are decreased in senescing cells, and frequently decreased in malignancies. This study identified a new drug candidate for colorectal cancer that appears to target cell senescence via a lamin protein. β-Asarone (1-propenyl-2,4,5-methoxybenzol) is a compound from the traditional medical herb Acorus calamus Linn. This study tested the in vitro and in vivo effects of β-asarone on colorectal cancer cells by testing cell viability using human colorectal cell lines HT29 and SW480 in MTT assays; tumorigenesis using xenografts in nude mice and a mouse model of colorectal cancer; cell senescence using senescence-associated β-galactosidase activity; and expression of cancer and senescence-related proteins, specifically lamins, Oct-1, p53, p21, and p15, by Western blot. β-Asarone appeared to increase expression of lamin B1, p53, p21, but not lamin A/C. β-Asarone regulates p15 expression by regulation of Oct-1 binding. Collectively, the results suggested that β-asarone inhibits colon cancer formation in vivo and in vitro by inducing senescence. Since β-asarone induced lamin B1 expression, a model is proposed in which β-asarone inhibits colorectal cancer by inducing senescence through lamin B1.

Interleukin-4 inhibits an early phase in the HIV-1 life cycle in the human colorectal cell line HT-29

Intestinal epithelial cells are continuously in contact with the gut-associated lymphoid tissues (GALT). Gastrointestinal infection by viruses, bacteria and parasites or the presence of an inflammatory bowel disease may influence the GALT cytokine network. However, the effect of the different cytokines on susceptibility of human intestinal epithelial cells to HIV-1 infection remains undefined. We demonstrate here that IL-4 inhibits infection with reporter HIV-1 viruses pseudotyped with NDK-Env without affecting integrated proviral DNA. Furthermore, IL-4 also inhibits, in a dose-dependent manner, infection of HT-29 cells with HIV-1-based AMLV, HTLV-I and VSV-G pseudotypes. A fusion assay showed that this event is not affected by IL-4, thus suggesting that a post-fusion step is affected. A reduction in the completion of DNA retrotranscription indicates that IL-4 may affect this step, or any prior event. Altogether our data indicate that IL-4 is negatively affecting an early post-fusion step in the HIV-1 replication cycle in HT-29 cells.

Antitumor activity of albendazole against the human colorectal cancer cell line HT-29: in vitro and in a xenograft model of peritoneal carcinomatosis

The peritoneal surface remains an important failure site for patients with colorectal cancer. We have recently shown that albendazole (ABZ), a safe and effective anthelmintic drug, has profound antitumor activity in hepatocellular cancer. Furthermore, albendazole also possesses unique physiochemical and pharmacokinetic properties probably making it a potential drug for use in the regional treatment of peritoneal carcinomatosis (PC). The current study was therefore designed to investigate this concept under both in vitro and in vivo conditions using human colorectal cancer cells HT-29. In cell culture, studies were conducted to investigate the effect of ABZ and its major metabolites, albendazole sulfoxide (ABZ-SO) and albendazole sulfone (ABZ-SO2) on the growth of human colorectal cell line HT-29. We also investigated the effects of ABZ on the cell cycle and the possible induction of apoptosis in these cells. Male nude mice inoculated intraperitoneally (i.p.) with HT-29 cells were treated with various schedules of ABZ given i.p. or orally for 6 weeks. Response was evaluated as the number of peritoneal tumor nodules present in animals at the end of the treatment period. In vitro, ABZ treatment of cells for 5 days led to profound inhibition of growth. (3)H-Thymidine assay and trypan blue viable cell counts confirmed the dose- and time-dependency of the ABZ effect, while recovery experiments revealed the reversible nature of this inhibition. ABZ-SO and ABZ-SO2 were also evaluated in cell culture studies and compared with the parent drug. In HT-29 cells, the IC(50) values were calculated to be 0.12 microM for ABZ and 2.35 microM for ABZ-SO. The other metabolite, ABZ-SO2, was completely inactive. Studies on the mechanism of ABZ action, revealed arrest of HT-29 cells at the G(2)/M phase of the cell cycle, while TUNEL, DNA laddering and caspase-3 activity all confirmed ABZ induced apoptosis. In nude mice with peritoneal HT-29 xenografts, ABZ profoundly inhibited peritoneal tumor growth. While alternate i.p. dosing (ABZ, 150 mg/kg) led to the highest degree of tumor growth suppression (P<0.001), schedules such as once-weekly dosing and even a single dose for the entire course of treatment (6 weeks) were also effective in reducing peritoneal tumor growth. However, no such activity was observed when ABZ was administered orally. This study shows for the first time the potent effect of regionally administered ABZ in suppressing the growth of peritoneal tumors of human colorectal origin. The effect is thought to be brought about by arresting tumor cells at the G(2)/M phase of the cycle and apoptosis. These findings provide evidence for potential value of ABZ in the treatment of regional PC arising from colorectal cell lines.

Down-regulation of CD59 (protectin) expression on human colorectal adenocarcinoma cell lines by levamisole.

The vulnerability of tumour cells to complement-mediated immune attack is regulated by membrane associated molecules. Recently, we have shown that the expression of the membrane attack complex inhibitor CD59 is enhanced on colonic adenocarcinoma cells compared to normal colonic epithelial cells. CD59 was shown, in the same study, to protect the tumour cells from complement-mediated lysis. Levamisole (LMS), used in conjunction with 5-fluorouracil as adjuvant therapy, reduces the incidence of colon cancer relapse following surgical resection. This led to our investigation of the effect of LMS on CD59 expression and function on the human colorectal cell lines HT29 and Caco-2. When cultured in the presence of 10 microM LMS, the cells reduced their expression of CD59 in a time-dependent manner. LMS treated HT29 cells were more sensitive to lysis by complement than control cells, and the reduction in CD59 expression was shown to be partly responsible for this. A reduction in CD59 expression will augment complement-mediated immune surveillance and may contribute to LMSs anti-tumour activity in vivo.

Selective toxicity of compounds naturally present in food toward the transformed phenotype of human colorectal cell line HT29

It has previously been observed that allyl isothiocyanate, a compound naturally present in the diet, is more cytotoxic toward the human colorectal adenocarcinoma cell line HT29 in its control transformed state than after exposure to sodium butyrate or to dimethylformamide, which slow growth and induce differentiation (detransformation). In the present study, a range of other dietary compounds were assayed for such selective toxicity. These compounds were chosen as constituents of foodstuffs that have been identified from epidemiologic studies as being potentially antitumorigenic and also as having anticarcinogenic activity in experimental models. Benzyl and phenethyl isothiocyanate, benzyl thiocyanate, and quercetin showed decreased toxicity towards HT29 after detransformation of the cells by one or both treatments, whereas no change was observed in the sensitivity to diallyl sulfide or diallyl disulfide. It is proposed that the presence of such selectively toxic compounds in the diet may inhibit the development of tumors by interfering with the growth of preneoplastic lesions while having little effect on normal cells. The cumulative effects of these inhibitions may contribute to the chemopreventive properties of the parent foodstuffs observed in epidemiologic studies.