Cho-Won Kim

Chemopreventive and chemotherapeutic effects of genistein, a soy isoflavone, upon cancer development and progression in preclinical animal models.

Genistein is one of isoflavones mostly derived in a leguminous plant. It is well known as one of phytoestrogens that have structures similar to the principal mammalian estrogen. It has diverse biological functions including chemopreventive properties against cancers. Anticancer efficacies of genistein have been related with the epidemiological observations indicating that the incidence of some cancers is much lower in Asia, where diets are rich in soyfoods, than Western countries. This review deals with in vivo anticancer activities of genistein identified in animal studies being divided into its effects on carcinogenesis and cancer progression. Because animal studies have advantages in designing the experiments to suit the goals, they imply diverse information on the anticancer activity of genistein. The in vivo animal studies have adopted the specific animal models according to a developmental stage of cancer to prove the anticancer efficacies of genistein against diverse types of cancer. The numerous previous studies insist that genistein effectively inhibits carcinogenesis in the DMBA-induced animal cancer models by reducing the incidence of adenocarcinoma and cancer progression in the transgenic and xenograft animal models by suppressing the tumor growth and metastatic transition. Although the protective effect of genistein against cancer has been controversial, genistein may be a candidate for chemoprevention of carcinogenesis and cancer progression and may deserve to be the central compound supporting the epidemiological evidence.

Anti-metastatic potential of resveratrol and its metabolites by the inhibition of epithelial-mesenchymal transition, migration, and invasion of malignant cancer cells

BACKGROUND Increased epithelial-mesenchymal transition (EMT) and cell migration and invasion abilities of cancer cells play important roles in the metastatic process of cancer. Resveratrol is a stilbenoid, a type of natural polyphenol found in the skin of grapes, berries, and peanuts. A number of experiments have examined resveratrols ability to target diverse pathways associated with carcinogenesis and cancer progression. PURPOSE This article aims to present updated overview of the knowledge that resveratrol and its metabolites or analogs have the potential to inhibit metastasis of cancer via affecting many signaling pathways related with EMT, cancer migration, and invasion in diverse organs of the body. CHAPTERS This article starts with a short introduction describing diverse beneficial effects of resveratrol including cancer prevention and the aim of the present study. To address the effects of resveratrol on cancer metastasis, mechanisms of EMT, migration, invasion, and their relevance with cancer metastasis, anti-metastatic effects of resveratrol through EMT-related signaling pathways and inhibitory effects of resveratrol on migration and invasion are highlighted. In addition, anti-metastatic potential of resveratrol metabolites and analogs is addressed. CONCLUSION Resveratrol was demonstrated to turn back the EMT process induced by diverse signaling pathways in several cellular and animal cancer models. In addition, resveratrol can exert chemopreventive efficacies on migration and invasion of cancer cells by inhibiting the related pathways and target molecules. Although these findings display the anti-metastatic potential of resveratrol, more patient-oriented clinical studies demonstrating the marked efficacies of resveratrol in humans are still needed.

Cigarette smoke extracts induced the colon cancer migration via regulating epithelial mesenchymal transition and metastatic genes in human colon cancer cells

There was considerable evidence that exposure to cigarette smoke is associated with an increased risk for colon cancer. Nevertheless, the mechanism underlying the relationship between cigarette smoking and colon cancer remains unclear. Moreover, there were only a few studies on effects of complexing substance contained in cigarette smoke on colon cancer. Thus, we further investigated whether cigarette smoke extract (CSE) affects the cell cycle, apoptosis and migration of human metastatic colon cancer cells, SW‐620. MTT assay revealed that SW‐620 cell proliferation was significantly inhibited following treatments with all CSEs, 3R4F, and two‐domestic cigarettes, for 9 days in a concentration‐dependent manner. Moreover, CSE treatments decreased cyclin D1 and E1, and increased p21 and p27 proteins by Western blot analysis in SW‐620 cells. Additionally, the treatment of the cells with CSE contributed to these effects expressing by apoptosis‐related proteins. An increased migration or invasion ability of SW‐620 cells following CSE treatment was also confirmed by a scratch or fibronectin invasion assay in vitro. In addition, the protein levels of E‐cadherin as an epithelial maker were down‐regulated, while the mesenchymal markers, N‐cadherin, snail, and slug, were up‐regulated in a time‐dependent manner. A metastatic marker, cathepsin D, was also down‐regulated by CSE treatment. Taken together, these results indicate that CSE exposure in colon cancer cells may deregulate the cell growth by altering the expression of cell cycle‐related proteins and pro‐apoptotic protein, and stimulate cell metastatic ability by altering epithelial‐mesenchymal transition (EMT) markers and cathepsin D expression.

Treatment of BG-1 Ovarian Cancer Cells Expressing Estrogen Receptors with Lambda-cyhalothrin and Cypermethrin Caused a Partial Estrogenicity Via an Estrogen Receptor-dependent Pathway.

Synthetic pyrethroids (SPs) are the most common pesticides which are recently used for indoor pest control. The widespread use of SPs has resulted in the increased exposure to wild animals and humans. Recently, some SPs are suspected as endocrine disrupting chemicals (EDCs) and have been assessed for their potential estrogenicity by adopting various analyzing assays. In this study, we examined the estrogenic effects of lambda-cyhalothrin (LC) and cypermethrin (CP), the most commonly used pesticides in Korea, using BG-1 ovarian cancer cells expressing estrogen receptors (ERs). To evaluate the estrogenic activities of two SPs, LC and CP, we employed MTT assay and reverse-transcription polymerase chain reaction (RT-PCR) in LC or CP treated BG-1 ovarian cancer cells. In MTT assay, LC (10−6 M) and CP (10−5 M) significantly induced the growth of BG-1 cancer cells. LC or CP-induced cell growth was antagonized by addition of ICI 182,720 (10−8 M), an ER antagonist, suggesting that this effect appears to be mediated by an ER-dependent manner. Moreover, RT-PCR results showed that transcriptional level of cyclin D1, a cell cycle-regulating gene, was significantly up-regulated by LC and CP, while these effects were reversed by co-treatment of ICI 182,780. However, p21, a cyclin D-ckd-4 inhibitor gene, was not altered by LC or CP. Moreover, ERα expression was not significantly changed by LC and CP, while downregulated by E2. Finally, in xenografted mouse model transplanted with human BG-1 ovarian cancer cells, E2 significantly increased the tumor volume compare to a negative control, but LC did not. Taken together, these results suggest that LC and CP may possess estrogenic potentials by stimulating the growth of BG-1 ovarian cancer cells via partially ER signaling pathway associated with cell cycle as did E2, but this estrogenic effect was not found in in vivo mouse model.

Effects of cigarette smoke extracts on the progression and metastasis of human ovarian cancer cells via regulating epithelial-mesenchymal transition

Cigarette smoke (CS) contains over 60 well-established carcinogens, and there are strong links between these carcinogens and smoking-induced cancers. In this study we investigated whether three types of cigarette smoke extracts (CSEs), 3R4F (standard cigarette), CSE1 and CSE2 (two commercial cigarettes), affect the proliferation, migration, and invasive activity of BG-1 human ovarian cancer cells. All three types of CSEs increased BG-1 cell proliferation at nicotine concentrations of 1.5μM-2.1μM in a cell viability assay. The protein expressions of cyclin D1 and cyclin E1 were increased, while p21 and p27 expression was decreased by Western blot assay. However, they did not show a consistent dose-dependent tendency. The protein expressions of Bax and p53, pro-apoptotic genes, were also decreased by CSEs. The expression of E-cadherin, an epithelial marker, was reduced in the treatment of CSEs while the expression of its reverse transition marker, N-cadherin, was slightly increased by CSEs containing 2.1μM of nicotine, but a statistical significance was not observed. Epithelial-mesenchymal transition (EMT)-associated transcriptional factors, Snail and Slug, were also up-regulated by treatment with CSEs, indicating that CSEs can increase the EMT process in BG-1 ovarian cancer cells. In addition, CSEs increased the migratory and invasive propensity of cancer cells. These functional alterations were associated with changes in metastasis-related gene expression. Upon exposure to CSEs, the expression of MMP-9 and cathepsin D was increased. Taken together, we confirmed that CSEs increased the growth, migration, and invasion of human ovarian cancer cells by regulating cell cycle, apoptosis, EMT, and metastasis related cellular markers and signaling proteins. Based on the results, cigarette smokers of women might be at a higher risk of ovarian cancer than non-smokers.

Effect of fenhexamid and cyprodinil on the expression of cell cycle- and metastasis-related genes via an estrogen receptor-dependent pathway in cellular and xenografted ovarian cancer models.

Fenhexamid and cyprodinil are antifungal agents (pesticides) used for agriculture, and are present at measurable amounts in fruits and vegetables. In the current study, the effects of fenhexamid and cyprodinil on cancer cell proliferation and metastasis were examined. Additionally, the protein expression levels of cyclin D1 and cyclin E as well as cathepsin D were analyzed in BG-1 ovarian cancer cells that express estrogen receptors (ERs). The cells were cultured with 0.1% dimethyl sulfoxide (DMSO; control), 17β-estradiol (E2; 10(-9)M), and fenhexamid or cyprodinil (10(-5)-10(-7)M). Results of a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that fenhexamid and cyprodinil increased BG-1 cell proliferation about 1.5 to 2 times similar to E2 (5 times) compared to the control. When the cells were co-treated with ICI 182,780 (10(-8)M), an ER antagonist, the proliferation of pesticide-treated BG-1 cells was decreased to the level of the control. A wound healing assay revealed that the pesticides reduced the disrupted area in the BG-1 cell monolayer similar to E2. Protein levels of cyclin D1 and E as well as cathepsin D were increased by fenhexamid and cyprodinil. This effect was reversed by co-treatment with ICI 182,780. In a xenograft mouse model with transplanted BG-1 cells, cyprodinil significantly increased tumor mass formation about 2 times as did E2 (6 times) compared to the vehicle (0.1% DMSO) over an 80-day period. In contrast, fenhexamid did not promote ovarian tumor formation in this mouse model. Cyprodinil also induced cell proliferation along with the expression of proliferating cell nuclear antigen (PCNA) and cathepsin D in tumor tissues similar to E2. Taken together, these results imply that fenhexamid and cyprodinil may have disruptive effects on ER-expressing cancer by altering the cell cycle- and metastasis-related gene expression via an ER-dependent pathway.

Immortalization of human corneal epithelial cells using simian virus 40 large T antigen and cell characterization.

INTRODUCTION Primary cultures of human corneal epithelial (HCE) cells usually cease to grow after four or five passages. This result in a small cell yield for experiments such as the eye irritancy test represents a serious problem for human and animal corneal epithelial research. In the present study, we established an HCE cell line immortalized by simian virus 40 (SV40), a polyomavirus, and characterized the inherent morphologic and cytologic cell properties. METHODS Primary cultured HCE cells were infected with a SV40 large T antigen (SV40 T)-expressing retrovirus, and were selected using G418 solution, an aminoglycoside antibiotic. To ensure that the immortalized cell lines express SV40 T and cytokeratin-3, a corneal epithelial-specific marker, we conducted reverse-transcription (RT)-PCR and Western blot analysis. RESULTS These cell lines continued to grow for more than 50 generations, exhibiting a cobble stone-like appearance similar to normal HCE cells and an increased proliferation rate compared to primary cultured HCE cells. RT-PCR results showed that the immortalized cell lines expressed SV40 T while the primary cultured cells did not. In the Western blot assay, protein levels of phosphorylated (Ser15) p53 protein were significantly decreased in the immortalized cell lines while the expression of total p53 protein was constant. In addition, expression of p21(cip1), a cell cycle protein, was down-regulated in the immortalized cells. Moreover, a cornea epithelium-specific marker, cytokeratin-3 (CK-3), was expressed at equal levels in the immortalized cells and primary HCE cells. DISCUSSION Taken together, these results indicate that immortalized HCE cell lines were successfully established using the SV40-retroviral vector. These cells may be an excellent model for detecting the adverse effects of standard toxic materials and could replace the traditional eye irritation test as an animal-free alternative method.

Effects of microalgal polyunsaturated fatty acid oil on body weight and lipid accumulation in the liver of C57BL/6 mice fed a high fat diet

Abstract Dietary polyunsaturated fatty acids (PUFAs), which are abundant in marine fish oils, have recently received global attention for their prominent anti-obesogenic effects. Among PUFAs, eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3), which are n-3 long-chain PUFAs widely referred to as omega-3 oils, were reported to prevent the development of obesity in rodents and humans. In the present study, we evaluated the anti-obesity effects of microalgal oil on high-fat induced obese C57BL/6 mice, compared with commercial omega-3 fish oil and vegetable corn oil. Microalgal oil is an inherent mixture of several PUFAs, including EPA, DHA and other fatty acids produced from a marine microalgal strain of Thraustochytriidae sp. derived mutant. It was found to contain more PUFAs (>80%) and more omega-3 oils than commercial omega-3 fish oil (PUFAs >31%) and corn oil (PUFAs 59%). All three types of oils induced weight loss in high-fat-induced obese mice, with the loss induced by microalgal oil being most significant at 9 weeks (10% reduction). However, the oils tested did not improve blood lipid levels, although microalgal oil showed an apparent inhibitory effect on lipid accumulation in the liver. These findings may be attributed to the higher PUFA content, including omega-3 oils of microalgal oil than other oils. Collectively, these findings suggest that microalgal oil, derived from Thraustochytriidae sp. derived mutant, is a prominent candidate for replacement of omega-3 fish oils based on its apparent anti-obesity effect in vivo.

Effects of cigarette smoke extracts on cell cycle, cell migration and endocrine activity in human placental cells

Maternal smoking during pregnancy is known to be related to adverse pregnancy results associated with trophoblast proliferation and cell cycle progression. Moreover, many previous studies have shown that cigarette smoke is correlated with human chorionic gonadotropin beta (hCG-β) subunit produced from syncytiotrophoblasts during pregnancy. Thus, we further investigated whether cigarette smoke extract (CSE) affects the cell proliferation, migration and endocrine hormone activity of JEG-3 human placental cancer cells. JEG-3 cell proliferation was significantly reduced by all CSEs in a concentration-dependent manner. Moreover, CSEs decreased proliferating cell nuclear antigen (PCNA) levels in JEG-3 cells in Western blot. Increased migration or invasion ability of JEG-3 cells following CSE treatment was also confirmed by a scratch or fibronectin invasion assay in vitro. Additionally, protein levels of E-cadherin as an epithelial maker were down-regulated, while the mesenchymal markers N-cadherin, snail and slug were up-regulated in a time-dependent manner. The metastasis marker, cathepsin D, was also down-regulated by CSE. Finally, CSEs significantly reduced the expression of hCG-β protein in JEG-3 cells. Overall, these results indicate that exposure of placental cells to CSE deregulates the cell cycle by altering the expression of cell cycle-related proteins and stimulates cell metastatic ability by altering EMT markers and cathepsin D expression. CSE exposure may also decrease hCG-β production as an endocrine marker, implying that cigarette smoke has adverse effects during pregnancy.

Gene therapy strategies using engineered stem cells for treating gynecologic and breast cancer patients (Review)

There are three types of stem cells: embryonic stem (ES) cells, adult stem (AS) cells and induced pluripotent stem (iPS) cells. These stem cells have many benefits including the potential ability to differentiate into various organs. In addition, engineered stem cells (GESTECs) designed for delivering therapeutic genes may be capable of treating human diseases including malignant cancers. Stem cells have been found to possess the potential for serving as novel delivery vehicles for therapeutic or suicide genes to primary or metastatic cancer formation sites as a part of gene-directed enzyme/prodrug combination therapy (GEPT). Given the advantageous properties of stem cells, tissue-derived stem cells are emerging as a new tool for anticancer therapy combined with prodrugs. In this review, the effects of GESTECs with different origins, i.e., neural, amniotic membrane and amniotic fluid, introduced to treat patients with diverse types of gynecologic and breast cancers are discussed. Data from the literature indicate the therapeutic potential of these cells as a part of gene therapy strategies to selectively target malignancies in women at clinically terminal stages.