Oral Squamous Cell Carcinoma Cells with Acquired Resistance to Erlotinib Are Sensitive to Anti-Cancer Effect of Quercetin via Pyruvate Kinase M2 (PKM2).

Oral squamous cell carcinoma (OSCC) frequently carries high epidermal growth factor receptor (EGFR) expression. Erlotinib, a small molecule tyrosine kinase inhibitor (TKI), is an effective inhibitor of EGFR activity; however, resistance to this drug can occur, limiting therapeutic outcomes. Therefore, in the current study, we aimed to unveil key intracellular molecules and adjuvant reagents to overcome erlotinib resistance. First, two HSC-3-derived erlotinib-resistant cell lines, ERL-R5 and ERL-R10, were established; both exhibited relatively higher growth rates, glucose utilization, epithelial-mesenchymal transition (EMT), and invasiveness compared with parental cells. Cancer aggressiveness-related proteins, such as N-cadherin, Vimentin, Twist, MMP-2, MMP-9, and MMP-13, and the glycolytic enzymes PKM2 and GLUT1 were upregulated in ERL-R cells. Notably, ERL-R cells were sensitive to quercetin, a naturally-existing flavonol phytochemical with anti-cancer properties against various cancer cells. At a concentration of 5 µM, quercetin effectively arrested cell growth, reduced glucose utilization, and inhibited cellular invasiveness. An ERL-R5-derived xenograft mouse model confirmed the growth-inhibitory efficacy of quercetin. Additionally, knock-down of PKM2 by siRNA mimicked the effect of quercetin and re-sensitized ERL-R cells to erlotinib. Furthermore, adding quercetin blocked the development of erlotinib-mediated resistance by enhancing apoptosis. In conclusion, our data support the application of quercetin in anti-erlotinib-resistant OSCC and indicate that PKM2 is a determinant factor in erlotinib resistance and quercetin sensitivity.

Luteolin ameliorates palmitate-induced lipotoxicity in hepatocytes by mediating endoplasmic reticulum stress and autophagy.

Abnormal accumulation of lipids in liver leads to uncontrolled endoplasmic reticulum (ER) stress and autophagy. Luteolin is known to have antioxidant, anti-inflammatory, and anti-cancer properties, but whether it protects against lipotoxicity in liver remains unclear. In this study, we challenged AML12 liver cells and mouse primary hepatocytes with palmitic acid (PA) with or without luteolin pretreatment. In the presence of PA, reactive oxygen species (ROS) production was increased at 3 h, followed by enhancement of expression of p-PERK, ATF4, p-eIF2α, CHOP, and TXNIP (ER stress markers) and p-p62 and LC3II/LC3I ratio (autophagy markers), in both primary hepatocytes and AML12 cells. When PA treatment was extended up to 24 h, apoptosis was induced as evidenced by an increase in caspase-3 activation. RFP-GFP-LC3B transfection further revealed that the fusion of autophagosomes with lysosomes was damaged by PA. With luteolin treatment, the expression of antioxidant enzymes, i.e., heme oxygenase-1 and glutathione peroxidase, was upregulated, and PA-induced ROS production, ER stress, and cell death were dose-dependently ameliorated. Luteolin could also reverse the damage caused to autophagic flux. These results indicate that luteolin protects hepatocytes against PA assault by enhancing antioxidant defense, which can attenuate ER stress and autophagy as well as promote autophagic flux.

Bioactive Vitamin D Attenuates MED28-Mediated Cell Growth and Epithelial-Mesenchymal Transition in Human Colorectal Cancer Cells.

Inadequate vitamin D status may increase the risk of developing multiple types of cancer. Epidemiological studies suggest an inverse association between 25-hydroxyvitamin D3 (25(OH)D3) and malignancy, including colorectal cancer. Previous studies have suggested that MED28, a Mediator subunit involved in transcriptional regulation, is associated with the growth of colorectal cancer cells; however, its role in the progression of metastasis such as epithelial-mesenchymal transition (EMT) and cell migration of colorectal cancer is unclear at present. The aim of this study was to investigate a potentially suppressive effect of calcitriol, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), a bioactive form of vitamin D, and the role of MED28 in the progression of EMT in human colorectal cancer cells. Suppression of MED28 increased the expression of E-cadherin and reduced the expression of several mesenchymal and migration biomarkers and Wnt/ß-catenin signaling molecules, whereas overexpression of MED28 enhanced the EMT features. Calcitriol suppressed the expression of MED28, and the effect of calcitriol mirrored that of MED28 silencing. Our data indicate that calcitriol attenuated MED28-mediated cell growth and EMT in human colorectal cancer cells, underlining the significance of MED28 in the progression of colorectal cancer and supporting the potential translational application of calcitriol.

Correction: Green sweet potato leaves increase Nrf2-mediated antioxidant activity and facilitate benzo[a]pyrene metabolism in the liver by increasing phase II detoxifying enzyme activities in rats.

Correction for 'Green sweet potato leaves increase Nrf2-mediated antioxidant activity and facilitate benzo[a]pyrene metabolism in the liver by increasing phase II detoxifying enzyme activities in rats' by Ray-Yu Yang et al., Food Funct., 2022, https://doi.org/10.1039/d2fo01049f.

Green sweet potato leaves increase Nrf2-mediated antioxidant activity and facilitate benzo[a]pyrene metabolism in the liver by increasing phase II detoxifying enzyme activities in rats.

Sweet potato leaves (SPL) are a valuable source of phytonutrients with nutritional and various health-promoting benefits. This study evaluated the effects of green and purple SPL supplementation on hepatic xenobiotic-metabolizing enzymes (XME) and membrane transporters, and benzo[a]pyrene (B[a]P) metabolism and B[a]P accumulation in rats. The experiments were conducted in standard and B[a]P-treated rat models. The first experiment showed that rats fed a diet containing 5% (w/w) green or purple SPL for two weeks showed increased hepatic activity of cytochrome P-450 (CYP)1A1/1A2 and glutathione S-transferase. Green SPL supplementation also increased the CYP2C, CYP2D and CYP3A and multidrug resistance-associated protein 2 levels in the liver. Notably, green and purple SPL induced nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 protein expression and reduced oxidative stress in the liver. The second experiment was to evaluate the effects of green and purple SPL supplementation on B[a]P metabolism and B[a]P accumulation in rats. Rats were fed SPL diets (the same as experiment I) for two weeks. When rats were exposed to a single dose (25 mg per kg BW) of B[a]P, green SPL had no effect on B[a]P-induced elevation of CYP1A1 activity but induced GST activity in the intestinal mucosa and the liver. Green SPL also increased hepatic UDP-glucuronosyltransferase activity and reduced B[a]P levels in the plasma, liver, and intestinal mucosa. A lower plasma 8-hydroxy-2'-deoxyguanosine level was found after B[a]P treatment only in the green SPL group. This study suggests that, in the standard rat model, green and purple SPL may increase Nrf2-mediated antioxidant activity and facilitate the xenobiotic detoxification process by increasing hepatic XME and transporters. When exposed to B[a]P, however, only green SPL consumption may increase hepatic B[a]P metabolism and lower the B[a]P level in the liver by increasing phase II detoxifying enzyme activities.

Citrus depressa Hayata peel ameliorates nonalcoholic fatty liver and modulates the activity of hepatic drug-metabolizing enzymes and transporters in rats fed a high-fat diet.

Citrus depressa Hayata is a small, green citrus fruit native to Taiwan and Japan. Citrus peel contains polymethoxylated flavones, including nobiletin and tangeretin, and may exhibit strong antioxidant and anti-inflammatory activities. A preliminary study revealed that Citrus depressa Hayata peel (CDHP) ethanolic extract reduced fat accumulation and the concentration of reactive oxygen species in human HepG2 cells exposed to oleic acid. The effects of CDHP on the activity of hepatic drug-metabolizing enzymes and membrane transporters in high-fat (HF) diet-induced fatty liver were investigated. Male rats were fed a low-fat diet, a HF diet, and a HF diet containing 4% CDHP for 11 weeks. The low-fat and HF diet respectively contained 13.5% and 38.1% of daily total calories from dietary fat. CDHP supplementation reduced the HF diet-induced accumulation of triglycerides in the liver and lowered hepatic fatty acid synthase activity. Higher faecal excretions of cholesterol, triglycerides, and total bile acids were observed after CDHP treatment. CDHP lowered the HF diet-induced increase in the mRNA expressions of nuclear factor erythroid 2-related factor 2, aryl hydrocarbon receptor, pregnane X receptor, and peroxisome proliferator-activated receptor-α and the activities of cytochrome P-450 (CYP)1A1, 1A2, 2B, and 2E1. However, increased hepatic CYP3A activity was observed in rats fed the HF diet containing CDHP. A higher hepatic multidrug resistance-associated protein 2 level was observed after CDHP treatment. After CDHP administration (1 g per kg body weight) for 1 h, nobiletin was found in plasma and various tissues and was abundant in the liver. An in vitro study revealed that the activity of various CYP enzymes in liver microsomes was inhibited by CDHP ethanolic extract and nobiletin, with IC50 values ranging from 18.5 to 54.4 µg ml-1 and from 13.0 to 33.2 µM, respectively. The results of this study suggest that CDHP might reduce hepatic steatosis and alter drug-metabolizing enzymes and transporters in HF diet-induced nonalcoholic fatty liver diseases.

Calcitriol Suppresses Warburg Effect and Cell Growth in Human Colorectal Cancer Cells.

Increasing lines of evidence indicate that the biologically active form of vitamin D, calcitriol (1,25-dihydroxyvitamin D3), prevents cancer progression by reducing cell proliferation, increasing cell differentiation, and inhibiting angiogenesis, among other potential roles. Cancer cells in solid tumors preferably undergo the "Warburg effect" to support cell growth by upregulating glycolysis, and the glycolytic intermediates further serve as building blocks to generate biomass. The objective of the current study is to investigate whether calcitriol affects glucose metabolism and cell growth in human colorectal cancer cells. Calcitriol reduced the expression of cyclin D1 and c-Myc. In addition, calcitriol reduced the expression of glucose transporter 1 (GLUT1) and key glycolytic enzymes and decreased extracellular acidification rate but increased oxygen consumption rate in human colorectal cancer cells. In a subcutaneous HT29 xenograft NOD/SCID mouse model, the volume and weight of the tumors were smaller in the calcitriol groups as compared with the control group, and the expression levels of GLUT1 and glycolytic enzymes, hexokinase 2 and lactate dehydrogenase A, were also lower in the calcitriol groups in a dose-responsive manner. Our data indicate that calcitriol suppresses glycolysis and cell growth in human colorectal cancer cells, suggesting an inhibitory role of the biologically active form of vitamin D in colorectal cancer progression.

Regulatory role of transcription factor HBP1 in anticancer efficacy of EGFR inhibitor erlotinib in HNSCC.

BACKGROUND: Epidermal growth factor receptor (EGFR) is often hyperactivated in head and neck squamous cell carcinoma (HNSCC); however, its downstream mediators are not fully identified. Here, we investigate the role of transcription factor HBP1 in the anticancer efficacy of EGFR inhibitor erlotinib in HNSCC. METHODS: The effect of erlotinib and HBP1 on cell proliferation and invasion was examined by flow cytometric analysis and a Matrigel invasion assay, respectively. Oral tumor specimens were used to evaluate the association between the expression level of EGFR and HBP1, and metastatic potential. RESULTS: Erlotinib caused cell growth arrest in the G1 phase and sluggish invasion with a concomitant increase in HBP1 and p27 expression. The erlotinib effect was attenuated upon HBP1 knockdown. Analysis of oral tumor specimens revealed that the low HBP1/high EGFR status can predict metastatic potential. CONCLUSIONS: Our data support HBP1 as a crucial mediator of EGFR-targeting inhibitors in HNSCC.

Correction: CTGF increases matrix metalloproteinases expression and subsequently promotes tumor metastasis in human osteosarcoma through down-regulating miR-519d.

[This corrects the article DOI: 10.18632/oncotarget.1998.].

Matrix metalloproteinase-13 is a target gene of high-mobility group box-containing protein 1 in modulating oral cancer cell invasion.

Transcription factor high-mobility group box-containing protein 1 (HBP1) may function as a tumor suppressor in various types of cancer. In a previous study, we demonstrated that HBP1 suppressed cell invasion in oral cancer. To further understand the underlying mechanism, the current study is aimed at investigating how HBP1 exerts its antimetastatic potential in oral cancer. In a cell model, ectopic expression of HBP1 potently suppressed epithelial-mesenchymal transition, cellular migration, and invasion; conversely, HBP1 knockdown promoted these malignant phenotypes. The matrix metalloproteinase (MMP) family is highly implicated in tumor metastasis. Therefore, we examined the effect of HBP1 on the activation of the MMP members, MMP-2, -9, and -13 that are highly associated with the aggressiveness of oral cancer. Ectopic expression of HBP1 resulted in a mild reduction in the expression and activity of MMP-2 and -9, yet it had a potent inhibitory effect on MMP-13. In contrast, HBP1 knockdown strongly enhanced the activation of MMP-13. Further, we demonstrated that MMP-13 is a target of HBP1 transcription repression as evidenced by the identification of an HBP1 binding site in the cis proximal region of the MMP-13 promoter. More important, MMP-13 knockdown significantly alleviated HBP1 small interfering RNA-mediated promotion in cell invasion. Analysis of oral tumor specimens revealed that the low HBP1 (<0.3-fold)/high MMP-13 (>3-fold) status was associated with metastatic potential. All told, our study provides evidence supporting the idea that the HBP1-MMP-13 axis is a key regulator of the aggressiveness in oral cancer.

MED28 and forkhead box M1 (FOXM1) mediate matrix metalloproteinase 2 (MMP2)-dependent cellular migration in human nonsmall cell lung cancer (NSCLC) cells.

Non-small-cell lung cancer (NSCLC) accounts for the majority of the lung cancer cases that have become a leading cause of cancer deaths worldwide. Overexpression of transcription factor forkhead box M1 (FOXM1) is involved in the inauspicious development of several types of cancer, including lung tumor aggressiveness. Our laboratory has previously found that MED28, a Mediator subunit for transcriptional activation, modulates cell growth, epithelial-mesenchymal transition, migration, and invasion in human breast cancer cells. The objective of the current study is to investigate the potential role of MED28 and FOXM1 in NSCLC. In addition to A549 and PC9 cells, we also used a doxycycline-inducible system to generate FOXM1-overexpressed A549-DN cells, and we explored the connection of MED28 with FOXM1 and their effect on migration. Herein, we report that the increased expression levels of both MED28 and FOXM1 elevated the expression of matrix metalloproteinase 2 (MMP2), a metastasis marker, which enhanced cell migration and matrigel invasion of NSCLC cells. Furthermore, MED28 interacted with FOXM1, and both exhibited a mutual effect on the expression and subcellular localization. Moreover, MED28 small interfering RNA-mediated MMP2 gene suppression could be attenuated by inducible expression of a constitutively active form of FOXM1, which consequently restored the migration and invasion ability of NSCLC cells. Our data indicate that MED28 interacts with FOXM1, and each affects the expression and localization of the other, and, more importantly, both regulate MMP2-dependent migration and invasion in human lung cancer cells.

WISP-1 positively regulates angiogenesis by controlling VEGF-A expression in human osteosarcoma.

In recent years, much research has focused on the role of angiogenesis in osteosarcoma, which occurs predominantly in adolescents and young adults. The vascular endothelial growth factor-A (VEGF-A) pathway is the key regulator of angiogenesis and in osteosarcoma. VEGF-A expression has been recognized as a prognostic marker in angiogenesis. Aberrant WNT1-inducible signaling pathway protein-1 (WISP-1) expression is associated with various cancers. However, the function of WISP-1 in osteosarcoma angiogenesis is poorly understood. We demonstrate a positive correlation between WISP-1 and VEGF-A expression in human osteosarcoma. Moreover, we show that WISP-1 promotes VEGF-A expression in human osteosarcoma cells, subsequently inducing human endothelial progenitor cell (EPC) migration and tube formation. The focal adhesion kinase (FAK), Jun amino-terminal kinase (JNK), and hypoxia-inducible factor (HIF)-1α signaling pathways were activated after WISP-1 stimulation, while FAK, JNK, and HIF-1α inhibitors or small interfering RNA (siRNA) abolished WISP-1-induced VEGF-A expression and angiogenesis. In vitro and in vivo studies revealed down-regulation of microRNA-381 (miR-381) in WISP-1-induced VEGF-A expression and angiogenesis. Our findings reveal that WISP-1 enhances VEGF-A expression and angiogenesis through the FAK/JNK/HIF-1α signaling pathways, as well as via down-regulation of miR-381 expression. WISP-1 may be a promising target in osteosarcoma angiogenesis.

Transcription factor HBP1 is a direct anti-cancer target of transcription factor FOXO1 in invasive oral cancer.

Either FOXO1 or HBP1 transcription factor is a downstream effector of the PI3K/Akt pathway and associated with tumorigenesis. However, the relationship between FOXO1 and HBP1 in oral cancer remains unclear. Analysis of 30 oral tumor specimens revealed that mean mRNA levels of both FOXO1 and HBP1 in non-invasive and invasive oral tumors were found to be significantly lower than that of the control tissues, and the status of low FOXO1 and HBP1 (< 0.3 fold of the control) was associated with invasiveness of oral tumors. To investigate if HBP1 is a direct transcription target of FOXO1, we searched potential FOXO1 binding sites in the HBP1 promoter using the MAPPER Search Engine, and two putative FOXO1 binding sites located in the HBP1 promoter -132 to -125 bp and -343 to -336 bp were predicted. These binding sites were then confirmed by both reporter gene assays and the in cellulo ChIP assay. In addition, Akt activity manipulated by PI3K inhibitor LY294002 or Akt mutants was shown to negatively affect FOXO1-mediated HBP1 promoter activation and gene expression. Last, the biological significance of the FOXO1-HBP1 axis in oral cancer malignancy was evaluated in cell growth, colony formation, and invasiveness. The results indicated that HBP1 knockdown potently promoted malignant phenotypes of oral cancer and the suppressive effect of FOXO1 on cell growth, colony formation, and invasion was alleviated upon HBP1 knockdown in invasive oral cancer cells. Taken together, our data provide evidence for HBP1 as a direct downstream target of FOXO1 in oral cancer malignancy.

MED28 Regulates Epithelial-Mesenchymal Transition Through NFκB in Human Breast Cancer Cells.

MED28, a mammalian Mediator subunit, was found highly expressed in several types of malignancy, including breast cancer. Recently, we have identified a role of MED28 in regulating both cell growth and migration in human breast cancer cells. In epithelium-derived solid tumor, migration and invasion are preceded by the progression of epithelial-mesenchymal transition (EMT) which calls for downregulation of epithelial markers as well as upregulation of mesenchymal markers, among other features. The objective of this study was to investigate a putative role of MED28 in the progression of EMT in human breast cancer cells. In fibroblast-like MDA-MB-231 cells, suppression of MED28 attenuated the mesenchymal morphology, concomitantly with a reduction of several mesenchymal biomarkers and Snail, a transcriptional repressor of E-cadherin. The suppression effect was also accompanied by downregulation of p-NFκB/p65. However, overexpression of MED28 exhibited in an opposite manner. In epithelial MCF7 cells, administration of Adriamycin®, an experimental EMT induction system, led to a mesenchyme-like appearance correlated with increased expression of MED28, p-p65, and Snail, and a reciprocal change of epithelial and mesenchymal markers. Furthermore, suppression of MED28 attenuated the experimental EMT effect and restored the original expression status of E-cadherin and MMP9 in MCF7 cells. Our data indicate that MED28 modulates the development of EMT through NFκB in human breast cancer cells, further reinforcing the significance of MED28 in the progression of breast cancer on top of its role in cell growth and migration. J. Cell. Physiol. 232: 1337-1345, 2017. © 2016 Wiley Periodicals, Inc.

Quercetin suppresses cellular migration and invasion in human head and neck squamous cell carcinoma (HNSCC).

Head and neck squamous cell carcinoma (HNSCC) with aberrant epidermal growth factor receptor (EGFR) signaling is often associated with a poor prognosis and a low survival rate. Hence, efficient inhibition of the EGFR signaling-mediated malignancy would improve survival rate. In a previous study, we demonstrated that quercetin appears to be a potent anti-tumorigenic agent through its inhibition of the EGFR/Akt pathway in oral cancer, but its anti-metastatic potential in HNSCC remains unclear [1]. Here, we have hypothesized that quercetin might be effective in metastatic inhibition in EGFR-overexpressing HNSCC cells. Quercetin treatment with 10 µM (half concentration of IC50) suppressed cell migration and invasion in EGFR-overexpressing HSC-3 and FaDu HNSCC cells. Quercetin also inhibited the colony growth of HSC-3 cells embedded in a Matrigel matrix. Among matrix metalloproteinases (MMPs), the secreted gelatinases MMP-2 and MMP-9 are responsible for the degradation of gelatin in the extracellular matrix and type IV collagen in the basement membrane; and this degradation event is crucial for the migration from the origin and the invasion into the bone in HNSCC. Quercetin (10 µM) treatment also suppressed the expression and proteolytic activity of MMP-2 and MMP-9. Taken together, our data indicate that quercetin is an effective anti-cancer agent against MMP-2- and MMP-9-mediated metastasis in EGFR-overexpressing HNSCC.

Adiponectin promotes VEGF-C-dependent lymphangiogenesis by inhibiting miR-27b through a CaMKII/AMPK/p38 signaling pathway in human chondrosarcoma cells.

Chondrosarcoma is the second most frequently occurring type of bone malignancy characterized by distant metastatic propensity. Vascular endothelial growth factor-C (VEGF-C) is the major lymphangiogenic factor, and makes crucial contributions to tumour lymphangiogenesis and lymphatic metastasis. Adiponectin is a protein hormone secreted predominantly by differentiated adipocytes. In recent years, adiponectin has also been indicated as facilitating tumorigenesis, angiogenesis and metastasis. However, the effect of adiponectin on VEGF-C regulation and lymphangiogenesis in chondrosarcoma has remained largely a mystery. In the present study, we have shown a clinical correlation between adiponectin and VEGF-C, as well as tumour stage, in human chondrosarcoma tissues. We further demonstrated that adiponectin promoted VEGF-C expression and secretion in human chondrosarcoma cells. The conditioned medium from adiponectin-treated cells significantly induced tube formation and migration of human lymphatic endothelial cells. In addition, adiponectin knock down inhibited lymphangiogenesis in vitro and in vivo We also found that adiponectin-induced VEGF-C is mediated by the calmodulin-dependent protein kinase II (CaMKII), AMP-activated protein kinase (AMPK) and p38 signaling pathway. Furthermore, the expression of miR-27b was negatively regulated by adiponectin via the CaMKII, AMPK and p38 cascade. The present study is the first to describe the mechanism of adiponectin-promoted lymphangiogenesis by up-regulating VEGF-C expression in chondrosarcomas. Thus, adiponectin could serve as a therapeutic target in chondrosarcoma metastasis and lymphangiogenesis.

Characteristics of resistin in rheumatoid arthritis angiogenesis.

Adipokines have been reported to be involved in the regulation of various physiological processes, including the immune response. Rheumatoid arthritis (RA) is an example of a systemic immune disease that causes chronic inflammation of the synovium and bone destruction in the joint. Recent therapeutic strategies based on the understanding of the role of cytokines and cellular mechanisms in RA have improved our understanding of angiogenesis. On the other hand, endogenous endothelial progenitor cells, which are a population isolated from peripheral blood monocytes have recently been identified as a homing target for pro-angiogeneic factor and vessel formation. In this review, we summarize the effects of common adipokines, such as adiponectin, leptin and resistin in RA pathogenesis and discuss other potential mechanisms of relevance for the therapeutic treatment of RA.

Interleukin-1ß induces fibroblast growth factor 2 expression and subsequently promotes endothelial progenitor cell angiogenesis in chondrocytes.

Arthritis is a process of chronic inflammation that results in joint damage. IL (interleukin)-1ß is an inflammatory cytokine that acts as a key mediator of cartilage degradation, and is abundantly expressed in arthritis. Neovascularization is one of the pathological characteristics of arthritis. However, the role of IL-1ß in the angiogenesis of chondrocytes remains unknown. In the present study, we demonstrate that stimulating chondrocytes (ATDC5) with IL-1ß increased the expression of FGF (fibroblast growth factor)-2, a potent angiogenic inducer, and then promoted EPC (endothelial progenitor cell) tube formation and migration. In addition, FGF-2-neutralizing antibody abolished ATDC5-conditional medium-mediated angiogenesis in vitro, as well as its angiogenic effects in the CAM (chick chorioallantoic membrane) assay and Matrigel plug nude mice model in vivo. IHC (immunohistochemistry) staining from a CIA (collagen-induced arthritis) mouse model also demonstrates that arthritis increased the expression of IL-1ß and FGF-2, as well as EPC homing in articular cartilage. Moreover, IL-1ß-induced FGF-2 expression via IL-1RI (type-1 IL-1 receptor), ROS (reactive oxygen species) generation, AMPK (AMP-activated protein kinase), p38 and NF-κB (nuclear factor κB) pathway has been demonstrated. On the basis of these findings, we conclude that IL-1ß promotes FGF-2 expression in chondrocytes through the ROS/AMPK/p38/NF-κB signalling pathway and subsequently increases EPC angiogenesis. Therefore IL-1ß serves as a link between inflammation and angiogenesis during arthritis.

All Trans-Retinoic Acid Mediates MED28/HMG Box-Containing Protein 1 (HBP1)/ß-Catenin Signaling in Human Colorectal Cancer Cells.

Vitamin A is required for normal body function, including vision, epithelial integrity, growth, and differentiation. All trans-retinoic acid (ATRA), a family member of vitamin A, has been explored in treating acute promyelocytic leukemia and other types of cancer. Dysregulated Wnt/ß-catenin signaling and disrupted cadherin-catenin complex often contribute to colorectal malignancy. MED28, a mammalian Mediator subunit, is found highly expressed in breast and colorectal cancers. Our laboratory has also reported that MED28 regulates cell growth, migration, and invasion in human breast cancer cells. In the current study we investigated the effect of ATRA on MED28 and Wnt/ß-catenin signaling in colorectal cancer. HCT116, HT29, SW480, and SW620, four human colorectal cancer cell lines representing different stages of carcinogenesis and harboring critical genetic changes, were employed. Our data indicated that regardless of genetic variations among these cells, suppression of MED28 reduced the expression of cyclin D1, c-Myc, and nuclear ß-catenin, but increased the expression of E-cadherin and HMG box-containing protein 1 (HBP1) where HBP1 has been described as a negative regulator of the Wnt/ß-catenin signaling. The reporter activity of an HBP1 promoter increased upon MED28 knockdown, but decreased upon MED28 overexpression. ATRA reduced the expression of MED28 and mimicked the effect of MED28 suppression in down-regulating Wnt/ß-catenin signaling. Taken together, ATRA can reverse the suppressive effect of MED28 on HBP1 and E-cadherin and inactivate the Wnt/ß-catenin pathway in colorectal cancer, suggesting a protective effect of ATRA against colorectal cancer. J. Cell. Physiol. 231: 1796-1803, 2016. © 2015 Wiley Periodicals, Inc.

Osteopontin Promotes Oncostatin M Production in Human Osteoblasts: Implication of Rheumatoid Arthritis Therapy.

Accumulating evidence indicates that subchondral bone might play an essential role in rheumatoid arthritis (RA). Osteopontin (OPN) induces the production of an important proinflammatory cytokine involved in the pathogenesis of RA. This study evaluated the activation of oncostatin M (OSM) by OPN in human primary osteoblasts to understand RA pathogenesis and characterized the intracellular signaling pathways involved in this activation. Quantitative PCR, ELISA, and Western blot results indicated that stimulation of human primary osteoblasts with OPN induces OSM expression through αvß3 integrin/c-Src/platelet-derived growth factor receptor transactivation/MEK/ERK. Treatment of osteoblasts with OPN also increased c-Jun phosphorylation, AP-1 luciferase activity, and c-Jun binding to the AP-1 element on the OSM promoter, as demonstrated using chromatin immunoprecipitation assay. Moreover, inhibition of OPN expression using lentiviral-OPN short hairpin RNA resulted in the amelioration of articular swelling, cartilage erosion, and OSM expression in the ankle joint of mice with collagen-induced arthritis as shown using microcomputed tomography and immunohistochemistry staining. Our results imply that OSM expression in osteoblasts increases in response to OPN-induced inflammation in vitro. Finally, lentiviral-OPN short hairpin RNA ameliorates the inflammatory response and bone destruction in mice with collagen-induced arthritis. Therefore, OPN may be a potential therapeutic target for RA.