The inhibitory effect of Gremlin-2 on adipogenesis suppresses breast cancer cell growth and metastasis.

BACKGROUND: Gremlin-1 (GREM1) and Gremlin-2 (GREM2) are bone morphogenetic protein antagonists that play important roles in organogenesis, tissue differentiation, and tissue homeostasis. Although GREM1 has been reported to be involved in promoting various cancers, little has been reported about effects of GREM2 on cancer. Recently, it has been reported that GREM2 can inhibit adipogenesis in adipose-derived stromal/stem cells. However, as an inhibitor of adipogenesis, the role of GREM2 in cancer progression is not well understood yet. METHODS: Pre-adipocyte 3T3-L1 cells overexpressing mock or Grem2 were established using a lentiviral transduction system and differentiated into adipocytes-mock and adipocytes-Grem2, respectively. To investigate the effect of adipocyte-Grem2 on breast cancer cells, we analyzed the proliferative and invasion abilities of spheroids using a 3D co-culture system of breast cancer cells and adipocytes or conditioned medium (CM) of adipocytes. An orthotopic breast cancer mouse model was used to examine the role of adipocytes-Grem2 in breast cancer progression. RESULTS: Grem2 overexpression suppressed adipogenesis of 3T3-L1 cells. Proliferative and invasion abilities of spheroids formed by co-culturing MTV/TM-011 breast cancer cells and adipocytes-Grem2 were significantly reduced compared to those of spheroids formed by co-culturing MTV/TM-011 cells and adipocytes-mock. Compared to adipocytes-mock, adipocytes-Grem2 showed decreased mRNA expression of several adipokines, notably IL-6. The concentration of IL-6 in the CM of these cells was also decreased. Proliferative and invasive abilities of breast cancer cells reduced by adipocytes-Grem2 were restored by IL-6 treatment. Expression levels of vimentin, slug, and twist1 in breast cancer cells were decreased by treatment with CM of adipocytes-Grem2 but increased by IL-6 treatment. In orthotopic breast cancer mouse model, mice injected with both MTV/TM-011 cells and adipocytes-Grem2 showed smaller primary tumors and lower lung metastasis than controls. However, IL-6 administration increased both the size of primary tumor and the number of metastatic lung lesions, which were reduced by adipocytes-Grem2. CONCLUSIONS: Our study suggests that GREM2 overexpression in adipocytes can inhibit adipogenesis, reduce the expression and secretion of several adipokines, including IL-6, and ultimately inhibit breast cancer progression.

Diesel exhaust particle exposure accelerates oxidative DNA damage and cytotoxicity in normal human bronchial epithelial cells through PD-L1.

Diesel exhaust particles (DEPs) are a major cause of cancer progression as well as a variety of acute and chronic diseases. It is well-known that programmed death-ligand 1 (PD-L1) is an immune checkpoint molecule that can induce immune escape in tumor cells. However, the function of PD-L1 in bronchial epithelial cells or how PD-L1 relates to cellular oxidation under DEPs-mediated oxidative stress is not well known. In this study, we investigated how PD-L1 affected DEPs-induced oxidative stress and cytotoxicity in human bronchial epithelial (HBE) cells, Beas-2B. DEPs not only induced intracellular reactive oxygen species (ROS) production, but also increased PD-L1 expression in HBE cells. Beas-2B cells overexpressing PD-L1 showed higher levels of ROS production, DNA damage, and apoptosis after DEPs treatment compared to control cells. In particular, the expression of an antioxidant enzyme heme-oxygenase-1 (HO-1) and nuclear translocation and transcriptional activity of Nrf2, a major regulator of HO-1, were lower in Beas-2B overexpressing PD-L1 cells than in control cells. DEPs-induced ROS generation, DNA damage and apoptosis in Beas-2B cells overexpressing PD-L1 were significantly restored by overexpressing HO-1. Collectively, our results suggest that DEPs can increase the expression of PD-L1 in HBE cells and that overexpressing PD-L1 might eventually promote DEPs-induced oxidative DNA damage and apoptosis.

Celastrol suppresses the growth of vestibular schwannoma in mice by promoting the degradation of ß-catenin.

Vestibular schwannoma (VS), one of characteristic tumors of neurofibromatosis type 2 (NF2), is an intracranial tumor that arises from Schwann cells of the vestibular nerve. VS results in hearing loss, tinnitus, dizziness, and even death, but there are currently no FDA-approved drugs for treatment. In this study, we established a high-throughput screening to discover effective compounds that could inhibit the viability of VS cells. Among 1019 natural products from the Korea Chemical Bank screened, we found that celastrol, a pentacyclic triterpene derived from a Tripterygium Wilfordi plant, exerted potent inhibitory effect on the viability of VS cells with an IC50 value of 0.5 µM. Celastrol (0.5, 1 µM) dose-dependently inhibited the proliferation of primary VS cells derived from VS patients. Celastrol also inhibited the growth, and induced apoptosis of two other VS cell lines (HEI-193 and SC4). Aberrant activation of Wnt/ß-catenin signaling has been found in VS isolated from clinically defined NF2 patients. In HEI-193 and SC4 cells, we demonstrated that celastrol (0.1, 0.5 µM) dose-dependently inhibited TOPFlash reporter activity and protein expression of ß-catenin, but not mRNA level of ß-catenin. Furthermore, celastrol accelerated the degradation of ß-catenin by promoting the formation of the ß-catenin destruction complex. In nude mice bearing VS cell line SC4 allografts, administration of celastrol (1.25 mg · kg-1 · d-1, i.p. once every 3 days for 2 weeks) significantly suppressed the tumor growth without showing toxicity. Collectively, this study demonstrates that celastrol can inhibit Wnt/ß-catenin signaling by promoting the degradation of ß-catenin, consequently inhibiting the growth of VS.

Sauchinone inhibits the proliferation, migration and invasion of breast cancer cells by suppressing Akt-CREB-MMP13 signaling pathway.

Sauchinone, a lignan isolated from Saururus chinenesis, is known to exhibit anti-inflammatory and anti-oxidant effects. Recently, sauchinone has been reported to inhibit the growth of various cancer cells, but its effects on breast cancer cells remain poorly understood. In the present study, we investigated the effects of sauchinone on the growth of breast cancer cells along with the underlying molecular mechanisms. Our results show that sauchinone treatment markedly inhibited the proliferation, migration, and invasion of breast cancer cells. Sauchinone reduced the phosphorylation of Akt, ERK, and CREB increased by transforming growth factor-ß (TGF-ß). In particular, sauchinone treatment suppressed the expression of matrix metalloproteinase (MMP)-13 (MMP13) by regulating the Akt-CREB signaling pathway. Sauchinone was less effective in inhibiting cell migration in Mmp13-knockdown cells than in control cells, suggesting that MMP13 may be a novel target for sauchinone. Our study suggests that sauchinone inhibits the growth of breast cancer cells by attenuating the Akt-CREB-MMP13 pathway. In addition, the targeted inhibition of MMP13 by sauchinone represents a promising approach for the treatment of breast cancer.

Gremlin-1 Promotes Metastasis of Breast Cancer Cells by Activating STAT3-MMP13 Signaling Pathway.

Gremlin-1 (GREM1), one of the bone morphogenetic protein (BMP) antagonists, can directly bind to BMPs. GREM1 is involved in organogenesis, tissue differentiation, and organ fibrosis. Recently, numerous studies have reported the oncogenic role of GREM1 in cancer. However, the role of GREM1 in metastasis of breast cancer cells and its underlying mechanisms remain poorly understood. The role of GREM1 in breast cancer progression was assessed by measuring growth, migration, and invasion of breast cancer cells. An orthotopic breast cancer mouse model was used to investigate the role of GREM1 in lung metastasis of breast cancer cells. GREM1 knockdown suppressed the proliferation of breast cancer cells, while its overexpression increased their growth, migration, and invasion. Cells with Grem1-knockdown showed much lower tumor growth rates and lung metastasis than control cells. GREM1 enhanced the expression of matrix metalloproteinase 13 (MMP13). A positive correlation between GREM1 and MMP13 expression was observed in breast cancer patients. GREM1 activated signal transducer and activator of transcription 3 (STAT3) transcription factor involved in the expression of MMP13. Our study suggests that GREM1 can promote lung metastasis of breast cancer cells through the STAT3-MMP13 pathway. In addition, GREM1 might be a promising therapeutic target for breast cancer metastasis.

Gremlin-1 activates Akt/STAT3 signaling, which increases the glycolysis rate in breast cancer cells.

Gremlin-1 (GREM1), one of the antagonists of bone morphogenetic proteins (BMPs), has recently been reported to be overexpressed in a variety of cancers including breast cancer. GREM1 is involved in tumor promotion, but little is known about its role in the glycolysis of cancer cells. In this study, we investigated the role of GREM1 in glycolysis of breast cancer cells and its underlying molecular mechanisms. We first observed that glucose uptake and lactate production were increased in GREM1-overexpressing breast cancer cells. GREM1 increased the expression of hexokinase-2 (HK2), which catalyzes the phosphorylation of glucose, the first step in glycolysis. In addition, GREM1 activated STAT3 transcription factor through the ROS-Akt signaling pathway. The ROS-Akt-STAT3 axis activated by GREM1 was involved in promoting glucose uptake by increasing the expression of HK2 in breast cancer cells. Therefore, our study suggested a new mechanism by which GREM1 is involved in breast cancer promotion by increasing glycolysis in breast cancer cells.

DHA inhibits Gremlin-1-induced epithelial-to-mesenchymal transition via ERK suppression in human breast cancer cells.

Docosahexaenoic acid (DHA) is an omega-3 fatty acid abundant in fish oils. It is known to have an inhibitory effect on various diseases such as inflammation, diabetes, and cancer. Epithelial-to-mesenchymal transition (EMT) is a process that epithelial cells gain migratory property to become mesenchymal cells involved in wound healing, organ fibrosis, and cancer progression. Gremlin-1 (GREM1) is a bone morphogenetic protein antagonist known to play a role in EMT. However, the role of GREM1 in the induction of EMT in human breast cancer cells and the effect of DHA on GREM1-induced EMT remain unclear. Establishment of GREM1 knockdown cell lines was performed using lentiviral shRNAs. Expression of EMT markers was determined by qRT-PCR and Western blotting. Effect of GREM1 and/or DHA on cell migration was investigated using wound healing assay. The level of GREM1 expression in human breast cancer tissues was determined by Oncomine database mining. GREM1 induced the expression of genes including N-cadherin, vimentin, and Slug. GREM1 promoted the migration of human breast cancer cells. GREM1 enhanced the expression of phosphorylated extracellular signal-regulated kinase (p-ERK) and the ERK activation was involved in EMT. Interestingly, DHA reduced the expression of GREM1. DHA also inhibited the expression of mesenchymal cell-associated genes and cell migration induced by GREM1. Furthermore, DHA suppressed the expression of p-ERK induced by GREM1. These results indicate that GREM1-ERK axis plays a role in EMT in human breast cancer cells and DHA is a putative compound that can inhibit EMT by inhibiting GREM1 signal transduction.

Red meat intake, CYP2E1 and PPARγ polymorphisms, and colorectal cancer risk.

The association between red meat intake and colorectal cancer (CRC) may be modulated by genetic polymorphisms of cytochrome P450 2E1 (CYP2E1), a key enzyme in the metabolism of nitrosamines, and peroxisome proliferator-activated receptor gamma (PPARγ), a transcription factor involved in adipogenesis and lipid and glucose metabolism. We conducted a case-control study of 971 patients with CRC and 658 controls who were admitted to two university hospitals between 1995 and 2004 in Seoul, Korea. Participants were asked about red meat intake by using a validated food frequency questionnaire. Polymorphisms of CYP2E1 (rs3813867) and PPARγ (rs1801282 or rs3856806) were identified using the TaqMan assay. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using multivariable logistic regression models. We found that the association between red meat and CRC varied by CYP2E1 polymorphisms; ORs (95% CIs) for at least five or more vs. less than one time/week of red meat intake were 2.77 (1.23-6.25) among individuals with C alleles of CYP2E1 and 0.89 (0.51-1.54) among individuals with the GG allele (Pinteraction=0.05). Compared with those individuals with the CC allele, increasing risk of CRC with increasing red meat intake was more pronounced among individuals with T alleles of PPARγC161T (rs3856806), but the association was not significant. Our data provide evidence that East Asians with the variant type of CYP2E1 may have high susceptibility to development of CRC risk.

Liner programming method to construct equated item sets for implementation of periodical computer-based testing of Korean medical licensing examination.

PURPOSE: This study aimed to find the best way of developing equivalent item sets and to propose a stable and effective management plan for the periodical licensing examinations. METHODS: Five pre-equated item sets were developed based on the predicted correct answer rate of each item by using linear programming. These pre-equated item sets were compared to the ones that were developed with random item selection method based on the actual answer rate and difficulty from item response theory (IRT). Also, the results with and without common items were compared in the same way. ACAR and the IRT difficulty was used to determine whether there is a significant difference between pre-equating conditions. RESULTS: There was a statistically significant difference in IRT difficulty among the results from different pre-equated conditions. As predicted correct answer rate was divided into 2 or 3 difficulty boundaries, the actual answer rate and IRT difficulty parameters of the 5 item sets were equally constructed. Comparing item sets conditions with common items and without common items, including common items did not contribute much for the equating of 5 item sets. CONCLUSION: This study suggested the linear programming method is applicable to construct equated-item sets that reflect each content area. The best method to construct equated item sets suggested is to divide the predicted correct answer rate into 2 or 3 difficulty boundaries regardless of common items. If pre-equated item sets are required to construct a test based on the actual data, several optimal methods should be considered by simulation studies before administrating a real test.

Association between beverage intake and obesity in children: The Korea National Health and Nutrition Examination Survey (KNHANES) 2013-2015.

BACKGROUND/OBJECTIVES: Numerous researches have studied the association between sugar intake and obesity of children in many countries. This study was undertaken to investigate the association between beverage intake and obesity of children by reviewing a database for total sugar contents established in all foods and presented in a nutrition survey by the Korea National Health and Nutrition Examination Survey (KNHANES). SUBJECTS/METHODS: Data of 1,520 children aged 6-11 years in the 6th KNHANES (2013-2015) were analyzed for this study. A database for total sugar intake comprises the total sugar contents of all foods included in the results of a nutrition survey using the 24-hour recall method of 6th KNHANES. Beverages were categorized into carbonated beverages, fruit & vegetable drinks, other drinks, tea, and coffee. RESULTS: The average daily beverage intake of all children was 131.75 g/day, and the average daily total sugar intake in beverages was 13.76 g/day. Carbonated beverages had the highest intake rate (58.85 g/day) and also ranked highest for sugar intake (6.36 g/day). After adjusting for confounding variables, the odds ratio for obesity in children with beverage intake of ≥ 200 mL/day significantly increased by 1.83 times (95% CI, 1.11-3.00) as compared to children with beverage intake of < 200 mL/day. Also, a significant increase was observed in the odds ratio for obesity in total children (2.41 times; 95% CI, 1.35-4.33) and boys (3.15 times; 95% CI, 1.53-6.49) with carbonated beverage intake of ≥ 200 mL/day when compared with children who consumed < 200 mL/day. CONCLUSION: A positive association is observed between beverage intake and obesity in Korean children. In particular, an intake of carbonated beverages has a positive correlation with childhood obesity in boys. This study can therefore be used as scientific evidence for reducing sugar, and for the continuous management and research on beverages.

Dietary pattern and health-related quality of life among breast cancer survivors.

BACKGROUND: There is limited evidence for the association between dietary pattern and quality of life among breast cancer survivors. We examined the association between dietary patterns and health-related quality of life (HRQoL) among Korean breast cancer survivors. METHODS: Our study included a total of 232 women, aged 21 to 79 years, who had been diagnosed with stage I to III breast cancer and who underwent breast cancer surgery at least 6 months prior to our baseline evaluation. We assessed HRQoL using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) and the Quality of Life Questionnaire Breast Cancer Module 23 (QLQ-BR23). We conducted a factor analysis to identify the major dietary patterns and used a generalized linear model to obtain the least squares mean (LS mean) and 95% confidence interval (CI) for HRQoL according to the dietary pattern scores. RESULTS: We identified 2 major dietary patterns: the Healthy dietary pattern and the Western dietary pattern. We found that breast cancer survivors who had higher Healthy dietary pattern scores tended to have lower dyspnea scores but higher insomnia scores, compared to breast cancer survivors with lower Healthy dietary pattern scores. For dyspnea, the LS mean (95% CI) was 8.86 (5.05-15.52) in the bottom quartile and 2.87 (1.62-5.08) in the top quartile (p for trend = 0.005). This association was limited to survivors with stage I for dyspnea or survivors with stage II or III for insomnia. CONCLUSIONS: Healthy dietary patterns were associated with better scores for dyspnea but worse scores for insomnia among breast cancer survivors. Other components of EORTC QLQ did not vary by dietary patterns overall, but they warrant further investigation for subgroups of breast cancer survivors.

Dietary diversity and nutritional adequacy among married Filipino immigrant women: The Filipino Women's Diet and Health Study (FiLWHEL).

BACKGROUND: Migration has an influence on health behavior and food intake. Dietary variety is a key component to high-quality diets because a single food item does not contain a variety of nutrients and may not reflect nutritional adequacy. We aimed to compare the dietary diversity scores (DDS), food variety scores (FVS), and nutrient adequacy levels of married Filipino immigrant women in Korea to those of Korean women. METHODS: We matched the data of 474 participants aged 20-57 years from the Filipino Women's Diet and Health Study (FiLWHEL) by age category with those of married Korean women randomly selected from the Korea National Health and Nutrition Examination Survey (KNHANES). Dietary information in FiLWHEL and KNHANES were assessed through the 24-hour recall method. We calculated the DDS by summing the number of eleven food groups consumed (DDS 10 g if they consumed at least 10 g/day; DDS all if they consumed any amount) and the FVS by counting the number of food items consumed. For nutrient adequacy, we calculated the probability of adequacy (PA) and intake below the estimated average requirement (EAR). RESULTS: Filipino women had a lower DDS and FVS in comparison to Korean women. The means (±SDs) of DDS 10 g, DDS all, and FVS for Filipino women versus Korean women were 6.0 (±1.6) versus 6.8 (±1.5) (p < 0.001), 6.7 (±1.7) versus 7.9 (±1.4) (p < 0.001) and 9.2 (±3.3) versus 14.7 (±4.9) (p < 0.001), respectively. When we compared each food group, the intakes of fish, other seafood, legumes/seeds/nuts, eggs, vegetables, and fruits were lower for Filipino women than for Korean women. The mean probability of adequacy (MPA) of nutrient intake of the nine selected nutrients was lower for Filipino women in comparison to Korean women. The mean (±SD) was 0.55 (±0.28) versus 0.66 (±0.26), respectively. CONCLUSIONS: Our findings showed that married Filipino immigrant women in Korea had lower dietary variety scores in comparison to Korean women. This was reflected in their nutritional adequacy. Nutrition education focusing on the promotion of eating a variety of foods may be needed for Filipino immigrant women in Korea.