• BMB Reports
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• v.54 no.8
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• pp.431-436
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• 2021

In recent years, restoring anti-tumor immunity has garnered a growing interest in cancer treatment. As potential therapeutics, immune checkpoint inhibitors have demonstrated benefits in many clinical studies. Although various methods have been applied to suppress immune checkpoints to boost anti-tumor immunity, including the use of immune checkpoint inhibitors, there are still unmet clinical needs to improve the response rate of cancer treatment. Here, we show that acetate can suppress the expression of poliovirus receptor (PVR/CD155), a ligand for immune checkpoint, in colon cancer cells. We demonstrated that acetate treatment could enhance effector responses of CD8⁺ T cells by decreasing the expression of PVR/CD155 in cancer cells. We also found that acetate could reduce the expression of PVR/CD155 by deactivating the PI3K/AKT pathway. These results demonstrate that acetate-mediated expression of PVR/CD155 in cancer cells might potentiate the anti-tumor immunity in the microenvironment of cancer. Our findings indicate that maintaining particular acetate concentrations could be a complementary strategy in current cancer treatment.

• BMB Reports
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• v.48 no.2
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• pp.115-120
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• 2015

Tight junction protein 1 (TJP1), a component of tight junction, has been reported to play a role in protein networks as an adaptor protein, and TJP1 expression is altered during tumor development. Here, we found that TJP1 expression was increased at the RNA and protein levels in TGF-${\beta}$-stimulated lung cancer cells, A549. SB431542, a type-I TGF-${\beta}$ receptor inhibitor, as well as SB203580, a p38 kinase inhibitor, significantly abrogated the effect of TGF-${\beta}$ on TJP1 expression. Diphenyleneiodonium, an NADPH oxidase inhibitor, also attenuated TJP1 expression in response to TGF-${\beta}$ in lung cancer cells. When TJP1 expression was reduced by shRNA lentiviral particles in A549 cells (A549-sh TJP1), wound healing was much lower than in cells infected with control viral particles. Taken together, these data suggest that TGF-${\beta}$ enhances TJP1 expression, which may play a role beyond structural support in tight junctions during cancer development.

• Journal of Pharmacopuncture
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• v.15 no.3
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• pp.19-30
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• 2012

Objectives: Many efforts have shown multi-oncologic roles of galectin-3 for cell proliferation, angiogenesis, and apoptosis. However, the mechanisms by which galectin-3 is involved in cell proliferation are not yet fully understood, especially in human colon cancer cells. Methods: To cluster genes showing positively or negatively correlated expression with galectin-3, we employed human colon cancer cell lines, SNU-61, SNU-81, SNU-769B, SNU-C4 and SNU-C5 in high-throughput gene expression profiling. Gene and protein expression levels were determined by using real-time quantitative polymerase chain reaction (PCR) and western blot analysis, respectively. The proliferation rate of human colon cancer cells was measured by using a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Results: Expression of ${\gamma}$-aminobutyric acid B receptor 1 (GABABR1) showed a positive correlation with galectin-3 at both the transcriptional and the translational levels. Down-regulation of galectin-3 decreased not only GABABR1 expression but also the proliferation rate of human colon cancer cells. However, Korean herbal extract, HangAmDan-B (HAD-B), decreased expression of GABABR1 without any expressional change of galectin-3, and offset ${\gamma}$-aminobutyric acid (GABA)-enhanced human colon cancer cell proliferation. Conclusions: Our present study confirmed that GABABR1 expression was regulated by galectin-3. HAD-B induced galectin-3-independent down-regulation of GABABR1, which resulted in a decreased proliferation of human colon cancer cells. The therapeutic effect of HAD-B for the treatment of human colon cancer needs to be further validated.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.23
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• pp.10245-10250
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• 2015

Background: Glucocorticoids are commonly co-administered with chemotherapy to prevent drug-induced allergic reactions, nausea, and vomiting, and have anti-tumor functions clinically; however, the distinct effects of GC on subtypes of tumor cells, especially in breast cancer cells, are still not well understood. In this study, we aimed to clarify the effect of GC on subtypes of T47D breast cancer cells by focusing on apoptosis, cell organization and migration, and underluing molecular mechanisms. Materials and Methods: The cell scratch test was performed to observe the cell migration rate in T47D cells treated with dexamethasone (Dex). Hoechst and MTT assays were conducted to detect cell survival and rhodamine-labeled phalloidin staining to observe cytoskeleton dynamics. Related factors in the AKT/mTOR pathway were determined by Western blotting. Results: Dex treatment could effectively inhibit T47D breast cancer cell migration with disruption of the cytoskeletal dynamic organization. Moreover, the effect of Dex on cell migration and cytoskeleton may be mediated by AKT/mTOR/RhoA pathway. Although Dex inhibited T47D cell migration, it alone may not induce cell apoptosis in T47D cells. Conclusions: Dex in T47D human breast cancer cells could effectively inhibit cell migration by disrupting the cytoskeletal dynamic organization, which may be mediated by the AKT/mTOR/RhoA pathway. Our work suggests that glucocorticoid/Dex clinical use may prove helpful for the treatment of breast cancer metastasis.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.1
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• pp.61-66
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• 2014

Lung cancer is still the number one cause of death from cancer worldwide. The clinical effect of platinum-based chemotherapy for non-small cell lung cancer is constrained by the resistance to drug. To overcome chemo-resistance, various modified treatment including combination therapy has been used, but overall survival has not been improved yet. In this study, chemo-resistant lung cancer cells, A549/Cis and H460/Cis, were developed by long-term exposure of cells to cisplatin and the proliferative capability of these resistant cells was verified to be reduced. We found cytotoxic effect of epigallocatechin gallate (EGCG), a major catechin derived from green tea, on both the parental lung cancer cells, A549 and H460, and their cisplatin resistant cells, A549/Cis and H460/Cis. ELISA and Western blot analysis revealed that EGCG was able to increase interlukine-6 (IL-6) production per cell, whereas its downstream effector Signal transducers and activators of transcription 3 (STAT3) phosphorylation was not changed by EGCG, indicating that IL-6/STAT3 axis is not the critical signaling to be inhibited by EGCG. We next found that EGCG suppresses the expression of both Axl and Tyro 3 receptor tyrosine kinases at mRNA and protein level, explaining the cytotoxic effect of EGCG on lung cancer cells, especially, regardless of cisplatin resistance. Taken together, these data suggest that EGCG impedes proliferation of lung cancer cells including their chemo-resistant variants through downregulation of Axl and Tyro 3 expression.

• Biomolecules & Therapeutics
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• v.20 no.6
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• pp.513-519
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• 2012

Although the immense efforts have been made for cancer prevention, early diagnosis, and treatment, cancer morbidity and mortality has not been decreased during last forty years. Especially, lung cancer is top-ranked in cancer-associated human death. Therefore, effective strategy is strongly required for the management of lung cancer. In the present study, we found that novel daphnane diterpenoids, yuanhualine (YL), yuanhuahine (YH) and yuanhuagine (YG) isolated from the flower of Daphne genkwa (Thymelaeaceae), exhibited potent anti-proliferative activities against human lung A549 cells with the $IC_{50}$ values of 7.0, 15.2 and 24.7 nM, respectively. Flow cytometric analysis revealed that the daphnane diterpenoids induced cell-cycle arrest in the G0/G1 as well as G2/M phase in A549 cells. The cell-cycle arrests were well correlated with the expression of checkpoint proteins including the up-regulation of cyclin-dependent kinase inhibitor p21 and p53 and down-regulation of cyclin A, cyclin B1, cyclin E, cyclin dependent kinase 4, cdc2, phosphorylation of Rb and cMyc expression. In the analysis of signal transduction molecules, the daphnane diterpenoids suppressed the activation of Akt, STAT3 and Src in human lung cancer cells. The daphnane diterpenoids also exerted the potent anti-proliferative activity against anticancer-drug resistant cancer cells including gemcitabine-resistant A549, gefitinib-, erlotinib-resistant H292 cells. Synergistic effects in the growth inhibition were also observed when yuanhualine was combined with gemcitabine, gefitinib or erlotinib in A549 cells. Taken together, these findings suggest that the novel daphnane diterpenoids might provide lead candidates for the development of therapeutic agents for human lung cancers.

• Biomolecules & Therapeutics
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• v.29 no.6
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• pp.650-657
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• 2021

Metformin is an anti-diabetic drug and has anticancer effects on various cancers. Several studies have suggested that metformin reduces cell proliferation and stimulates cell-cycle arrest and apoptosis. However, the definitive molecular mechanism of metformin in the pathophysiological signaling in endometrial tumorigenesis and metastasis is not clearly understood. In this study, we examined the effects of metformin on the cell viability and apoptosis of human cervical HeLa and endometrial HEC-1-A and KLE cancer cells. Metformin suppressed cell growth in a dose-dependent manner and dramatically evoked apoptosis in HeLa cervical cancer cells, while apoptotic cell death and growth inhibition were not observed in endometrial (HEC-1-A, KLE) cell lines. Accordingly, the p27 and p21 promoter activities were enhanced while Bcl-2 and IL-6 activities were significantly reduced by metformin treatment. Metformin diminished the phosphorylation of mTOR, p70S6K and 4E-BP1 by accelerating adenosine monophosphate-activated kinase (AMPK) in HeLa cancer cells, but it did not affect other cell lines. To determine why the anti-proliferative effects are observed only in HeLa cells, we examined the expression level of liver kinase B1 (LKB1) since metformin and LKB1 share the same signalling system, and we found that the LKB1 gene is not expressed only in HeLa cancer cells. Consistently, the overexpression of LKB1 in HeLa cancer cells prevented metformin-triggered apoptosis while LKB1 knockdown significantly increased apoptosis in HEC-1-A and KLE cancer cells. Taken together, these findings indicate an underlying biological/physiological molecular function specifically for metformin-triggered apoptosis dependent on the presence of the LKB1 gene in tumorigenesis.

• International Journal of Oral Biology
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• v.46 no.1
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• pp.7-14
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• 2021

Vinpocetine induces anti-inflammatory effects in various inflammatory diseases via the inhibition of phosphodiesterase type-1-independent nuclear factor-κB signaling pathway and the release of inflammatory cytokines. In this study, we investigated the effect of vinpocetine on the proliferation of colon cancer cells and its underlying molecular mechanisms. Our data showed that vinpocetine inhibits the viability and proliferation of colon cancer cells. Vinpocetine treatment induced cell death in HCT116 cells, which the percentages of sub-G1 phase were significantly increased, and the apoptosis-related genes were regulated after HCT116 cells were treated with vinpocetine. In sum, our findings indicated that vinpocetine could be a therapeutically useful candidate in the treatment of colon cancer.

• IMMUNE NETWORK
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• v.12 no.6
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• pp.247-252
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• 2012

Pancreatic cancer is the fourth commonest cause of cancer-related deaths in the world. However, no adequate therapy for pancreatic cancer has yet been found. In this study, the antitumor activity of cytokine-induced killer (CIK) cells against the human pancreatic cancer was evaluated in vitro and in vivo. Human peripheral blood mononuclear cells were cultured with IL-2-containing medium in anti-CD3 for 14 days. The resulting populations of CIK cells comprised 94% $CD3^+$, 4% $CD3^-CD56^+$, 41% $CD3^+CD56^+$, 11% $CD4^+$, and 73% $CD8^+$. This heterogeneous cell population was called cytokine-induced killer (CIK) cells. At an effector-target cell ratio of 100 : 1, CIK cells destroyed 51% of AsPC-1 human pancreatic cancer cells, as measured by the $^{51}Cr$-release assay. In addition, CIK cells at doses of 3 and 10 million cells per mouse inhibited 42% and 70% of AsPC-1 tumor growth in nude mouse xenograft assays, respectively. This study suggests that CIK cells may be used as an adoptive immunotherapy for pancreatic cancer patients.

• Nutrition Research and Practice
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• v.3 no.2
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• pp.77-83
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• 2009

Retinoic acids (RAs) modulate growth, differentiation, and apoptosis in normal, pre-malignant & malignant cells. In the present study, the effects of RA isomers (all-trans RA, 13-cis RA, and 9-cis RA) on the cell signal transduction of human breast cancer cells have been studied. The relationship between RAs and an enzymatic antioxidant system was also determined. Estrogen-receptor (ER) positive MCF-7 and ER-negative MDA-MB-231 human breast cancer cells were treated with different doses of each RA isomers, all-trans RA, 13-cis RA, or 9-cis RA. Treatment of RA isomers inhibited cell viability and induced apoptosis of MCF-7 cells as a result of increased caspase activity in cytoplasm and cytochrome C released from mitochondria. All-trans RA was the most effective RA isomer in both cell growth inhibition and induction of apoptosis in MCF-7 cells. However, no significant effect of RA isomers was observed on the cell growth or apoptosis in ER-negative MDA-MB-231 cells. In addition, activities of antioxidant enzymes such as catalase and glutathione peroxidase were decreased effectively after treatment of RA in MCF-7 cells, whereas SOD activity was rarely affected. Thus, the present data suggest that all-trans RA is the most potential inducer of apoptosis and modulator of antioxidant enzymes among RA isomers in MCF-7 human breast cancer cells.