• Oncology Letters
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• v.18 no.6
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• pp.6361-6370
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• 2019

Angiogenesis is an essential step in cancer progression and metastasis. Changes in the microRNA (miRNA or miR) expression profiles of endothelial cells (ECs) elicited by cancer cells promote angiogenesis. Vascular endothelial growth factor (VEGF), a key pro-angiogenic factor, influences miRNA expression in ECs; however, the exact role that VEGF serves in miRNA regulation during angiogenesis is poorly defined. The present study aimed to demonstrate the differential angiogenic effects on human umbilical vein endothelial cells (HUVECs) of five different colorectal cancer (CRC) cell lines by in vitro HUVEC migration and angiogenesis assays in response to CRC-conditioned medium (CM). Among the tested CMs, LoVo was the most effective cell line in eliciting HUVEC angiogenic phenotypes, at least partially due to its high VEGF level. It was also observed that pro-angiogenesis-regulatory miRNAs (angio-miRNA) miR-296, miR-132, miR-105 and miR-200 were upregulated in the VEGF-rich LoVo CM compared with the VEGF-scarce SW620 CM. In addition, treatment with VEGF receptor 2 inhibitor downregulated the pro-angio-miRNAs, with the exception of miR-132, suggesting that VEGF, as well as additional signaling, is required for angio-miRNA expression. Quantitative analyses on pro-angio-miRNA target expression suggested that independent pathways may be involved in the regulation of their expression. Overall, the data from the present study indicated that multiple paracrine factors, including VEGF secreted by CRCs, effectively modulated angio-miRNA expression, thus impacting their target expression and the angiogenic phenotypes of HUVECs.

• Korean Journal of Plant Resources
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• v.31 no.3
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• pp.218-227
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• 2018

In this study, we investigated the effect of the extracts from Vaccinium oldhamii on cell proliferation and the regulatory mechanisms of cyclin D1 protein level in human cancer cells. The branch extracts from Vaccinium oldhamii (VOB) showed higher inhibitor effect against the cell growth than leave extracts (VOL) and fruit extracts (VOF) in human colorectal cancer, breast cancer, prostate cancer, non-small lung cancer, pancreatic cancer and liver cancer cells. In addition, VOB decreased cyclin D1 level at both protein and mRNA level. MG132 treatment attenuated VOB-mediated cyclin D1 downregulation. A point mutation of threonine-286 to alanine attenuated cyclin D1 degradation by VOB. In addition, the inhibition of nuclear export by leptomycin B (LMB) attenuated cyclin D1 degradation by VOB. But, the treatment of PD98059 (ERK1/2 inhibitor), SB203580 (p38 inhibitor), SP600125 (JNK inhibitor), LiCl ($GSK3{\beta}$ inhibitor), LY294002 (PI3K inhibitor) or BAY 11-7082 ($I{\kappa}K$ inhibitor) did not affect VOB-induced cyclin D1 degradation. In conclusion, VOB induced cyclin D1 degradation through redistribution of cyclin D1 from the nucleus to cytoplasm via T286 phosphorylation of cyclin D1, which resulted in the inhibition of cancer cell proliferation.

• Nutrition Research and Practice
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• v.9 no.4
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• pp.343-349
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• 2015

BACKGROUND/OBJECTIVES: Fermentation of dietary fiber results in production of various short chain fatty acids in the colon. In particular, butyrate is reported to regulate the physical and functional integrity of the normal colonic mucosa by altering mucin gene expression or the number of goblet cells. The objective of this study was to investigate whether butyrate modulates mucin secretion in LS174T human colorectal cells, thereby influencing the adhesion of probiotics such as Lactobacillus and Bifidobacterium strains and subsequently inhibiting pathogenic bacteria such as E. coli. In addition, possible signaling pathways involved in mucin gene regulation induced by butyrate treatment were also investigated. MATERIALS/METHODS: Mucin protein content assay and periodic acid-Schiff (PAS) staining were performed in LS174T cells treated with butyrate at various concentrations. Effects of butyrate on the ability of probiotics to adhere to LS174T cells and their competition with E. coli strains were examined. Real time polymerase chain reaction for mucin gene expression and Taqman array 96-well fast plate-based pathway analysis were performed on butyrate-treated LS174T cells. RESULTS: Treatment with butyrate resulted in a dose-dependent increase in mucin protein contents in LS174T cells with peak effects at 6 or 9 mM, which was further confirmed by PAS staining. Increase in mucin protein contents resulted in elevated adherence of probiotics, which subsequently reduced the adherent ability of E. coli. Treatment with butyrate also increased transcriptional levels of MUC3, MUC4, and MUC12, which was accompanied by higher gene expressions of signaling kinases and transcription factors involved in mitogen-activated protein kinase (MAPK) signaling pathways. CONCLUSIONS: Based on our results, butyrate is an effective regulator of modulation of mucin protein production at the transcriptional and translational levels, resulting in changes in the adherence of gut microflora. Butyrate potentially stimulates the MAPK signaling pathway in intestinal cells, which is positively correlated with gut defense.

• YAKHAK HOEJI
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• v.49 no.6
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• pp.511-517
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• 2005

Low sensitivity to anticancer drugs such as 5-fluorouracil (5-FU) has been associated with decreased expression of genes involved in cell proliferation, apoptosis and metastasis. Recently, it has been shown that the expression levels of some of these genes are reduced by transcription inhibition due to epigenetic silencing on CpG islands. Therefore, epigenetic therapy has been proposed, where epigenetic silencing is repressed with DNA methyltransferase (DNMT) inhibitors and histone deacetylase (HDAC) inhibitors alone or in combination with other chemotherapeutic agents. The aim of our study was to evaluate the combination effect of 5-FU and its association with the status of epigenetic silencing using methylation-specific PCR of $p14^{ARF}$ when given with S-aza-2'-deoxycytidine (5-aza-dC), a DNMT inhibitor and depsipeptide, an HDAC inhibitor in DLD-1 human colorectal cancer cells. The combination of 5-aza-dC with depsipeptide showed a synergism and induced unmethylation of $p14^{ARF}$. However, triplet combination of 5-aza-dc/depsipeptide and 5-FU resulted in antagonistic effects and abrogated unmethylation of $p14^{ARF}$. These results suggest that unfavorable interaction of 5-aza-dC/depsipeptide with 5-FU in DLD-1 cells may be related with the failure in repression of epigenetic silencing, which warrants further investigation.

• International Journal of Oncology
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• v.54 no.6
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• pp.2117-2126
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• 2019

Transforming growth factor-β1 (TGF-β1) is a multifunctional cytokine that functions as a growth suppressor in normal epithelial cells and early stage tumors, but acts as a tumor promoter during malignant progression. However, the molecular basis underlying the conversion of TGF-β1 function remains largely undefined. X-linked inhibitor of apoptosis-associated factor 1 (XAF1) is a pro-apoptotic tumor suppressor that frequently displays epigenetic inactivation in various types of human malignancies, including colorectal cancer. The present study explored whether the anti-apoptotic effect of TGF-β1 is linked to its regulatory effect on XAF1 induction in human colon cancer cells under stressful conditions. The results revealed that TGF-β1 treatment protected tumor cells from various apoptotic stresses, including 5-fluorouracil, etoposide and γ-irradiation. XAF1 expression was activated at the transcriptional level by these apoptotic stresses and TGF-β1 blocked the stress-mediated activation of the XAF1 promoter. The study also demonstrated that mitogen-activated protein kinase kinase inhibition or extracellular signal-activated kinase (Erk)1/2 depletion induced XAF1 induction, while the activation of K-Ras (G12C) led to its reduction. In addition, TGF-β1 blocked the stress-mediated XAF1 promoter activation and induction of apoptosis. This effect was abrogated if Erk1/2 was depleted, indicating that TGF-β1 represses XAF1 transcription through Erk activation, thereby protecting tumor cells from apoptotic stresses. These findings point to a novel molecular mechanism underlying the tumor-promoting function of TGF-β1, which may be utilized in the development of a novel therapeutic strategy for the treatment of colorectal cancer.

• Biomedical Science Letters
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• v.20 no.1
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• pp.32-38
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• 2014

Potassium cyanate (KOCN) that is known as an inducer of the protein carbamylation is an inorganic compound and is the conjugate based of cyanic acid (HOCN). Based on these studies, we confirmed that KOCN induces the apoptosis of the human colorectal cancer cell line, HCT 116 cells, by various mitochondrial pathways. To investigate other mechanisms of KOCN-mediated apoptosis, in the present study, we examined KOCN-induced cytokines production in HCT 116 cells and identified the intracellular signaling pathway in these processes. We first demonstrated that KOCN considerably increased the cell apoptosis via intracellular $Ca^{2+}$ signaling, mitochondrial dysfunction and ROS production. And then we examined TNF-${\alpha}$ and IL-$1{\beta}$ levels mediated by KOCN in HCT 116 cells. Although IL-$1{\beta}$ was not involved in KOCN-mediated HCT 116 cell apoptosis, the release of TNF-${\alpha}$ was mediated by KOCN in HCT 116 cells via NF-${\kappa}B$ activation. Apoptosis was also enhanced by incubation with supernatants from HCT 116 cells after KOCN treatment and this effect was partially reduced by BAY 11-7085 pre-treated supernatant. Taken together, our results indicate that KOCN-induced apoptosis in HCT 116 cells is dependent on the releases of TNF-${\alpha}$ and the increased factors and that the mechanism involves the activation of NF-${\kappa}B$.

• Journal of Ginseng Research
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• v.38 no.4
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• pp.251-255
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• 2014

Background: Ginsenoside Rp1 (G-Rp1) is a novel ginsenoside derived from ginsenoside Rk1. This compound was reported to have anticancer, anti-platelet, and anti-inflammatory activities. In this study, we examined the molecular target of the antiproliferative and proapoptotic activities of G-Rp1. Methods: To examine the effects of G-Rp1, cell proliferation assays, propidium iodine staining, proteomic analysis by two-dimensional gel electrophoresis, immunoblotting analysis, and a knockdown strategy were used. Results: G-Rp1 dose-dependently suppressed the proliferation of colorectal cancer LoVo cells and increased their apoptosis. G-Rp1 markedly upregulated the protein level of apolipoprotein (Apo)-A1 in LoVo, SNU-407, DLD-1, SNU-638, AGS, KPL-4, and SK-BR-3 cells. The knockdown of Apo-A1 by its small-interfering RNA increased the levels of cleaved poly(ADP-ribose) polymerase and p53 and diminished the proliferation of LoVo cells. Conclusion: These results suggest that G-Rp1 may act as an anticancer agent by strongly inhibiting cell proliferation and enhancing apoptosis through upregulation of Apo-A1.

• The Korean Journal of Food And Nutrition
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• v.35 no.5
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• pp.359-368
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• 2022

In this study, the quality characteristics of kimchi, such as its salinity, pH, and acidity, were measured and compared, and the HT-29 human colon cancer cells were used to show the anticancer effects of kimchi. The kimchi samples used herein included standard kimchi (SK), turnip kimchi (TK), and turnip-powder-added kimchi (TPK). The measured pH and acidity of TK and TPK showed no significant differences with those of SK. Compared to SK and TK, TPK had higher DPPH scavenging activity and higher total flavonoid content, confirming its antioxidant activity. The cancer cell growth inhibition rates of TK and TPK were significantly higher than that of SK. In HT-29 cells treated with TPK, the mRNA expression of Bcl-xL, an anti-apoptosis-related gene, was lower, and the mRNA expressions of the apoptosis-related genes Bax, Bad, and caspase-9 were higher. TPK showed significantly higher levels of mRNA expressions for the cell-cycle-related genes p53 and p21 than the other samples, in addition to suppression effects on cancer cell proliferation. Compared to SK, TK and TPK suppressed the growth of colon cancer cells and showed higher anticancer effects. Therefore, it is shown that kimchi with added turnip powder had high anticancer effects.

• Archives of Pharmacal Research
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• v.19 no.5
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• pp.342-347
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• 1996

Doxorubicin, one of the clinically most useful anticancer agents, is used alone or in combination with other drugs against a wide variety of tumors, recently. But cancer cells developed resistance to this agent in many ways. This resistance is an important limiting factor of doxorubicin for anticancer drug. We newly established doxorubicin-resistant HCT15/CL02 subline from parental HCT15 human adenocarcinoma colon cancer cells. HCT15/CL02 revealed resistance to doxorubicin about 85-fold of its parental cells, and it also revealed cross-resistance to actinomycin D, etoposide and vinblastine but not to displatin and tamoxifen. And verapamil, a reversal agent of multidrug-resistance (MDR) by P-glycoprotein, elevated the cytotoxicity of doxorubicin against both HCT15 and GCT15/CL02 cells. But the relative resistant rate was not reduced. Verapamil had no effects on the tosicity of cisplatin to the both cell lines. These results indicate that HCT15/CL02 cells have some functionally complex mechanisms for MDR.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.6
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• pp.509-516
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• 2014

Radiation therapy for variety of human solid tumors utilizes mechanism of cell death after DNA damage caused by radiation. In response to DNA damage, cytochrome c was released from mitochondria by activation of pro-apoptotic Bcl-2 family proteins, and then elicits massive $Ca^{2+}$ release from the ER that lead to cell death. It was also suggested that irradiation may cause the deregulation of $Ca^{2+}$ homeostasis and trigger programmed cell death and regulate death specific enzymes. Thus, in this study, we investigated how cellular $Ca^{2+}$ metabolism in RKO cells, in comparison to radiation-resistant A549 cells, was altered by gamma (${\gamma}$)-irradiation. In irradiated RKO cells, $Ca^{2+}$ influx via activation of NCX reverse mode was enhanced and a decline of $[Ca^{2+}]_i$ via forward mode was accelerated. The amount of $Ca^{2+}$ released from the ER in RKO cells by the activation of $IP_3$ receptor was also enhanced by irradiation. An increase in $[Ca^{2+}]_i$ via SOCI was enhanced in irradiated RKO cells, while that in A549 cells was depressed. These results suggest that ${\gamma}$-irradiation elicits enhancement of cellular $Ca^{2+}$ metabolism in radiation-sensitive RKO cells yielding programmed cell death.