Leptin increases VEGF expression and enhances angiogenesis in human chondrosarcoma cells.

BACKGROUND: Leptin, 16kDa product of obese gene, is adipocytokine playing critical role in regulation of body weight. In recent years, leptin is also defined as potent angiogenic factor involving in tumorigenesis, angiogenesis, and metastasis. However, it is unknown whether leptin regulates VEGF production in human chondrosarcoma and contributing the tumor-associated angiogenesis. METHODS: We analyzed protein level of leptin and VEGF in human chondrosarcoma tissues. Effects of leptin on chondrosarcoma cells were examined by in vitro and in vivo assays. In addition, intracellular signal pathways were investigated by pharmacological and genetic approaches. RESULTS: We found that both leptin and VEGF are highly expressed in human chondrosarcoma tissues, and positively correlated with tumor stage. Leptin increases VEGF production by activating OBRl receptor and MAPKs (p38, ERK, and JNK), which in turn enhances binding of AP-1 transcription factor to VEGF promoter, resulting in the transactivation of VEGF expression and subsequently promoting migration and tube formation in endothelial progenitor cells (EPCs). In vivo, knockdown leptin significantly reduces angiogenesis and tumor growth. CONCLUSION: Leptin may be a therapeutic target of angiogenesis and metastasis in chondrosarcoma. GENERAL SIGNIFICANCE: These findings provide better understanding of pathogenesis of chondrosarcoma and can utilize this knowledge to design new therapeutic strategy.

Paeonol suppresses chondrosarcoma metastasis through up-regulation of miR-141 by modulating PKCδ and c-Src signaling pathway.

Chondrosarcoma, a primary malignant bone cancer, has potential for local invasion and distant metastasis, especially to the lungs. Patients diagnosed with it show poor prognosis. Paeonol (2'-hydroxy-4'-methoxyacetophenone), the main active compound of traditional Chinese remedy Paeonia lactiflora Pallas, exhibits anti-inflammatory and anti-tumor activity; whether paeonol regulates metastatic chondrosarcoma is largely unknown. Here, we find paeonol do not increase apoptosis. By contrast, at non-cytotoxic concentrations, paeonol suppresses migration and invasion of chondrosarcoma cells. We also demonstrate paeonol enhancing miR-141 expression and miR-141 inhibitor reversing paeonol-inhibited cell motility; paeonol also reduces protein kinase C (PKC)d and c-Src kinase activity. Since paeonol inhibits migration and invasion of human chondrosarcoma via up-regulation of miR-141 via PKCd and c-Src pathways, it thus might be a novel anti-metastasis agent for treatment of metastatic chondrosarcoma.

Leptin induces oncostatin M production in osteoblasts by downregulating miR-93 through the Akt signaling pathway.

Inflammatory response and articular destruction are common symptoms of osteoarthritis (OA) and rheumatoid arthritis (RA). Leptin, an adipocyte-secreted hormone that centrally regulates weight control, may exert proinflammatory effects in the joint, depending on the immune response. Yet, the mechanism of leptin interacting with the arthritic inflammatory response is unclear. This study finds that leptin increased expression of oncostatin M (OSM) in human osteoblasts in a concentration- and time-dependent manner. In addition, OBRl, but not OBRs receptor antisense oligonucleotide, abolished the leptin-mediated increase of OSM expression. On the other hand, leptin inhibited miR-93 expression; an miR-93 mimic reversed leptin-increased OSM expression. Stimulation of osteoblasts with leptin promoted Akt phosphorylation, while pretreatment of cells with Akt inhibitor or siRNA reversed leptin-inhibited miR-93 expression. Our results showed that leptin heightened OSM expression by downregulating miR-93 through the Akt signaling pathway in osteoblasts, suggesting leptin as a novel target in arthritis treatment.

1-benzyl-2-phenylbenzimidazole (BPB), a benzimidazole derivative, induces cell apoptosis in human chondrosarcoma through intrinsic and extrinsic pathways.

In this study, we investigated the anticancer effects of a new benzimidazole derivative, 1-benzyl-2-phenyl -benzimidazole (BPB), in human chondrosarcoma cells. BPB-mediated apoptosis was assessed by the MTT assay and flow cytometry analysis. The in vivo efficacy was examined in a JJ012 xenograft model. Here we found that BPB induced apoptosis in human chondrosarcoma cell lines (JJ012 and SW1353) but not in primary chondrocytes. BPB induced upregulation of Bax, Bad and Bak, downregulation of Bcl-2, Bid and Bcl-XL and dysfunction of mitochondria in chondrosarcoma. In addition, BPB also promoted cytosolic releases AIF and Endo G. Furthermore, it triggered extrinsic death receptor-dependent pathway, which was characterized by activating Fas, FADD and caspase-8. Most importantly, animal studies revealed a dramatic 40% reduction in tumor volume after 21 days of treatment. Thus, BPB may be a novel anticancer agent for the treatment of chondrosarcoma.

Epigallocatechin-3-gallate induces cell apoptosis of human chondrosarcoma cells through apoptosis signal-regulating kinase 1 pathway.

Chondrosarcoma is a malignant primary bone tumor that responds poorly to both chemotherapy and radiation therapy. (-)-Epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, has been shown to inhibit tumorigenesis and cancer cell growth in animal models. The aim of this study was to elucidate the mechanism of EGCG-induced apoptosis of human chondrosarcoma cells. EGCG induced cell apoptosis in human chondrosarcoma cell lines but not primary chondrocytes. EGCG induced upregulation of Bax and Bak, downregulation of Bcl-2 and Bcl-XL, and dysfunction of mitochondria in chondrosarcoma. We also found that the accumulation of reactive oxygen species (ROS) is a critical mediator in EGCG-induced cell death. EGCG induced apoptosis signal-regulating kinase 1 (ASK1) dephosphorylation and its dissociation from 14-3-3. Treatment of chondrosarcoma cells with EGCG induced p38 and c-jun-NH2-kinase (JNK) phosphorylation. Transfection with ASK1 siRNA or p38 and JNK mutant antagonized the EGCG-induced cell apoptosis. Therefore, EGCG triggered ROS and activated the ASK1-p38/JNK pathway, resulting chondrosarcoma cell death. Importantly, animal studies revealed a dramatic reduction in tumor volume after 24 days of treatment. Thus, EGCG may be a novel anti-cancer agent for the treatment of chondrosarcoma.

Active ingredients in Chinese medicines promoting blood circulation as Na+/K+ -ATPase inhibitors.

The positive inotropic effect of cardiac glycosides lies in their reversible inhibition on the membrane-bound Na(+)/K(+)-ATPase in human myocardium. Steroid-like compounds containing a core structure similar to cardiac glycosides are found in many Chinese medicines conventionally used for promoting blood circulation. Some of them are demonstrated to be Na(+)/K(+)-ATPase inhibitors and thus putatively responsible for their therapeutic effects via the same molecular mechanism as cardiac glycosides. On the other hand, magnesium lithospermate B of danshen is also proposed to exert its cardiac therapeutic effect by effectively inhibiting Na(+)/K(+)-ATPase. Theoretical modeling suggests that the number of hydrogen bonds and the strength of hydrophobic interaction between the effective ingredients of various medicines and residues around the binding pocket of Na(+)/K(+)-ATPase are crucial for the inhibitory potency of these active ingredients. Ginsenosides, the active ingredients in ginseng and sanqi, substantially inhibit Na(+)/K(+)-ATPase when sugar moieties are attached only to the C-3 position of their steroid-like structure, equivalent to the sugar position in cardiac glycosides. Their inhibitory potency is abolished, however, when sugar moieties are linked to C-6 or C-20 position of the steroid nucleus; presumably, these sugar attachments lead to steric hindrance for the entrance of ginsenosides into the binding pocket of Na(+)/K(+)-ATPase. Neuroprotective effects of cardiac glycosides, several steroid-like compounds, and magnesium lithospermate B against ischemic stroke have been accordingly observed in a cortical brain slice-based assay model, and cumulative data support that effective inhibitors of Na(+)/K(+)-ATPase in the brain could be potential drugs for the treatment of ischemic stroke.

Functional expression and characterization of dipeptidyl peptidase IV from the black-bellied hornet Vespa basalis in Sf21 insect cells.

The maturation of mastoparan B, the major toxin peptide in the venom of Vespa basalis, requires enzymatic cleavage of its prosequence presumably via sequential liberation of dipeptides. The putative processing enzyme, dipeptidyl peptidase IV, was expressed as a glycosylated His-tag fusion protein (rDPP-IV) via the baculovirus expression system. rDPP-IV purified by one-step nickel-affinity chromatography was verified by Western blot and LC-MS/MS analysis. The k(cat)/K(m) of rDPP-IV was determined to be in the range of 10-500 mM(-1)·S(-1) for five synthetic substrates. The optimal temperature and pH for rDPP-IV were determined to be 50 °C and pH 9. Enzymatic activity of rDPP-IV was significantly reduced by 80 and 60% in the presence of sitagliptin and phenylmethylsulfonyl fluoride respectively.

Changes in volatile compounds upon aging and drying in oolong tea production.

BACKGROUND: Long-term storage (aging) with periodic drying of fresh oolong tea gives rise to so-called old oolong tea. Alteration of aroma compounds is expected when a fresh oolong tea is converted into an old one, as the two teas smell drastically different. The aim of this study was to compare the volatile compounds in fresh and old oolong teas. RESULTS: Significant differences were observed between the volatile compounds in fresh and old oolong teas. This observation suggested that long straight chains of alcohols and acids were putatively decomposed while shorter-chain acids, their amide derivatives and many nitrogen-containing compounds were generated during the tea conversion processes. The overall patterns of volatile compounds observed in five different preparations of old oolong tea were fundamentally identical. This consensus pattern was different from that observed in oolong tea either stored for more than 10 years without drying or prepared at relatively low temperatures and short baking time. CONCLUSION: Characteristic aroma nitrogen-containing compounds, including N-ethylsuccinimide, 2-acetylpyrrole, 2-formylpyrrole and 3-pyridinol, were consistently found in the examined old oolong teas. These compounds might be regarded as typical constituents at least for a certain kind of old oolong tea.

Nerve growth factor promotes lysyl oxidase-dependent chondrosarcoma cell metastasis by suppressing miR-149-5p synthesis.

Chondrosarcoma is a malignancy of soft tissue and bone that has a high propensity to metastasize to distant organs. Nerve growth factor (NGF) is critical for neuronal cell growth, apoptosis, and differentiation, and also appears to promote the progression and metastasis of several different types of tumors, although the effects of NGF upon chondrosarcoma mechanisms are not very clear. We report that NGF facilitates lysyl oxidase (LOX)-dependent cellular migration and invasion in human chondrosarcoma cells, and that NGF overexpression enhances lung metastasis in a mouse model of chondrosarcoma. NGF-induced stimulation of LOX production and cell motility occurs through the inhibition of miR-149-5p expression, which was reversed by PI3K, Akt, and mTOR inhibitors and their respective short interfering RNAs. Notably, levels of NGF and LOX expression correlated with tumor stage in human chondrosarcoma samples. Thus, NGF appears to be a worthwhile therapeutic target for metastatic chondrosarcoma.

IGFBP-3 stimulates human osteosarcoma cell migration by upregulating VCAM-1 expression.

AIMS: Insulin-like growth factor (IGF) signaling has been documented in several human malignancies and is thought to contribute to cellular differentiation and migration, as well as malignant progression. A major binding molecule of IGF, IGF-binding protein 3 (IGFBP-3), regulates multiple IGF effects. Here, we focused on the effect of IGFBP-3 in the motility of osteosarcoma cells and examined signaling regulation. MATERIALS AND METHODS: Using a human osteosarcoma tissue array, immunohistochemical staining determined levels of IGFBP-3 expression in osteosarcoma tissue and in normal tissue. The wound healing migration assay, Transwell migration assay, luciferase reporter assay, immunofluorescence staining, Western blot and real-time quantitative PCR were performed to examine whether IGFBP-3 facilitates VCAM-1-dependent migration of osteosarcoma cells. KEY FINDINGS: In this study, we found significantly higher IGFBP-3 levels in osteosarcoma tissue compared with normal healthy tissue. IGFBP-3 treatment of two human osteosarcoma cell lines promoted cell migration and upregulated levels of VCAM-1 expression via PI3K/Akt and AP-1 signaling. SIGNIFICANCE: IGFBP-3 appears to be a novel therapeutic target in metastatic osteosarcoma.

Bradykinin enhances cell migration in human chondrosarcoma cells through BK receptor signaling pathways.

Bradykinin (BK) is an inflammatory mediator, and shows elevated levels in regions of severe injury and inflammatory diseases. BK has recently been shown to be involved in carcinogenesis and cancer progression. In this study, we found that BK increased the migration and the expression of alpha2beta1 integrin in human chondrosarcoma cells. We also found that human chondrosarcoma tissues had significantly higher expression of the B1 and B2 receptors comparing to normal cartilage. BK-mediated migration and integrin up-regulation was attenuated by B1 and B2 BK receptor siRNA or antagonist. Activations of phospholipase C (PLC), protein kinase Cdelta (PKCdelta), and NF-kappaB pathways after BK treatment was demonstrated, and BK-induced integrin expression and migration activity was inhibited by the specific inhibitor of PLC, PKCdelta, and NF-kappaB cascades. Taken together, our results indicated that BK enhances the migration of chondrosarcoma cells by increasing alpha2beta1 integrin expression through the BK receptors/PLC/PKCdelta/NF-kappaB signal transduction pathway.

Cyclooxygenase-2 enhances alpha2beta1 integrin expression and cell migration via EP1 dependent signaling pathway in human chondrosarcoma cells.

BACKGROUND: Cyclooxygenase (COX)-2, the inducible isoform of prostaglandin (PG) synthase, has been implicated in tumor metastasis. Interaction of COX-2 with its specific EP receptors on the surface of cancer cells has been reported to induce cancer invasion. However, the effects of COX-2 on migration activity in human chondrosarcoma cells are mostly unknown. In this study, we examined whether COX-2 and EP interaction are involved in metastasis of human chondrosarcoma. RESULTS: We found that over-expression of COX-2 or exogenous PGE2 increased the migration of human chondrosarcoma cells. We also found that human chondrosarcoma tissues and chondrosarcoma cell lines had significant expression of the COX-2 which was higher than that in normal cartilage. By using pharmacological inhibitors or activators or genetic inhibition by the EP receptors, we discovered that the EP1 receptor but not other PGE receptors is involved in PGE2-mediated cell migration and alpha2beta1 integrin expression. Furthermore, we found that human chondrosarcoma tissues expressed a higher level of EP1 receptor than normal cartilage. PGE2-mediated migration and integrin up-regulation were attenuated by phospholipase C (PLC), protein kinase C (PKC) and c-Src inhibitor. Activation of the PLCbeta, PKCalpha, c-Src and NF-kappaB signaling pathway after PGE2 treatment was demonstrated, and PGE2-induced expression of integrin and migration activity were inhibited by the specific inhibitor, siRNA and mutants of PLC, PKC, c-Src and NF-kappaB cascades. CONCLUSIONS: Our results indicated that PGE2 enhances the migration of chondrosarcoma cells by increasing alpha2beta1 integrin expression through the EP1/PLC/PKCalpha/c-Src/NF-kappaB signal transduction pathway.

Steroid-like compounds in Chinese medicines promote blood circulation via inhibition of Na+/K+ -ATPase.

AIM: To examine if steroid-like compounds found in many Chinese medicinal products conventionally used for the promotion of blood circulation may act as active components via the same molecular mechanism triggered by cardiac glycosides, such as ouabain. METHODS: The inhibitory potency of ouabain and the identified steroid-like compounds on Na(+)/K(+)-ATPase activity was examined and compared. Molecular modeling was exhibited for the docking of these compounds to Na(+)/K(+)-ATPase. RESULTS: All the examined steroid-like compounds displayed more or less inhibition on Na(+)/K(+)-ATPase, with bufalin (structurally almost equivalent to ouabain) exhibiting significantly higher inhibitory potency than the others. In the pentacyclic triterpenoids examined, ursolic acid and oleanolic acid were moderate inhibitors of Na(+)/K(+)-ATPase, and their inhibitory potency was comparable to that of ginsenoside Rh2. The relatively high inhibitory potency of ursolic acid or oleanolic acid was due to the formation of a hydrogen bond between its carboxyl group and the Ile322 residue in the deep cavity close to two K(+) binding sites of Na(+)/K(+)-ATPase. Moreover, the drastic difference observed in the inhibitory potency of ouabain, bufalin, ginsenoside Rh2, and pentacyclic triterpenoids is ascribed mainly to the number of hydrogen bonds and partially to the strength of hydrophobic interaction between the compounds and residues around the deep cavity of Na(+)/K(+)-ATPase. CONCLUSION: Steroid-like compounds seem to contribute to therapeutic effects of many cardioactive Chinese medicinal products. Chinese herbs, such as Prunella vulgaris L, rich in ursolic acid, oleanolic acid and their glycoside derivatives may be adequate sources for cardiac therapy via effective inhibition on Na(+)/K(+)-ATPase.

Cyr61 increases migration and MMP-13 expression via alphavbeta3 integrin, FAK, ERK and AP-1-dependent pathway in human chondrosarcoma cells.

Cysteine-rich 61 (Cyr61), from the CCN gene family, is a secreted and matrix-associated protein, which is involved in many cellular activities such as growth and differentiation. However, the effect of Cyr61 on migration activity in human chondrosarcoma cells is mostly unknown. Here, we found that Cyr61 increased the migration and expression of matrix metalloproteinase (MMP)-13 in human chondrosarcoma cells (JJ012 cells). RGD peptide, alphavbeta3 monoclonal antibody and mitogen-activated protein kinase (MEK) inhibitors (PD98059 and U0126) but not RAD peptide inhibited the Cyr61-induced increase of the migration and MMP-13 upregulation of chondrosarcoma cells. Cyr61 stimulation increased the phosphorylation of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK). In addition, activator protein-1 (AP-1) decoy oligodeoxynucleotide also suppressed the MMP-13 messenger RNA and enzyme activity enhanced by Cyr61. Moreover, Cyr61 increased the binding of c-Fos and c-Jun to the AP-1 element on the MMP-13 promoter. Taken together, our results indicated that Cyr61 enhances the migration of chondrosarcoma cells by increasing MMP-13 expression through the alphavbeta3 integrin receptor, FAK, ERK, c-Fos/c-Jun and AP-1 signal transduction pathway.

Leptin enhances cell migration in human chondrosarcoma cells through OBRl leptin receptor.

Leptin, an adipocyte-derived cytokine that is closely associated with obesity, has recently been shown to be involved in carcinogenesis and cancer progression. Integrins are the major adhesive molecules in mammalian cells and have been associated with metastasis of cancer cells. In this study, we found that leptin increased the migration and the expression of alphavbeta3 integrin in human chondrosarcoma cells. We also found that human chondrosarcoma tissues and chondrosarcoma cell lines had significant expression of the long form (OBRl) leptin receptor, which was higher than that in normal cartilage and human primary chondrocyte. Leptin-mediated migration and integrin upregulation were attenuated by OBRl receptor antisense oligonucleotide. Activations of insulin receptor substrate (IRS)-1, phosphatidylinositol 3-kinase (PI3K), Akt and nuclear factor-kappaB (NF-kappaB) pathways after leptin treatment were demonstrated, and leptin-induced expression of integrin and migration activity was inhibited by the specific inhibitor, small-interfering RNA and mutant of IRS-1, PI3K, Akt and NF-kappaB cascades. Taken together, our results indicated that leptin enhances the migration of chondrosarcoma cells by increasing alphavbeta3 integrin expression through the OBR1/IRS-1/PI3K/Akt/NF-kappaB signal transduction pathway.

CCL5/CCR5 axis promotes the motility of human oral cancer cells.

CCL5 (previously called RANTES) is in the CC-chemokine family and plays a crucial role in the migration and metastasis of human cancer cells. On the other hand, the effect of CCL5 is mediated via CCR receptor. RT-PCR and flow cytometry studies demonstrated CCR5 but not CCR1 and CCR3 mRNA in oral cancer cell lines, especially higher in those with high invasiveness (SCC4) as compared with lower levels in HSC3 cells and SCC9 cells. Stimulation of oral cancer cells with CCL5 directly increased the migration and metalloproteinase-9 (MMP-9) production. MMP-9 small interfering RNA inhibited the CCL5-induced MMP-9 expression and thereby significantly inhibited the CCL5-induced cell migration. Activations of phospholipase C (PLC), protein kinase Cdelta (PKCdelta), and NF-kappaB pathways after CCL5 treatment was demonstrated, and CCL5-induced expression of MMP-9 and migration activity was inhibited by the specific inhibitor of PLC, PKCdelta, and NF-kappaB cascades. In addition, migration-prone sublines demonstrate that cells with increasing migration ability had more expression of MMP-9, CCL5, and CCR5. Taken together, these results indicate that CCL5/CCR5 axis enhanced migration of oral cancer cells through the increase of MMP-9 production.

Stromal cell-derived factor-1/CXCR4 enhanced motility of human osteosarcoma cells involves MEK1/2, ERK and NF-kappaB-dependent pathways.

Osteosarcoma is characterized by a high malignant and metastatic potential. The chemokine stromal-derived factor-1alpha (SDF-1alpha) and its receptor, CXCR4, play a crucial role in adhesion and migration of human cancer cells. Integrins are the major adhesive molecules in mammalian cells, and has been associated with metastasis of cancer cells. Here, we found that human osteosarcoma cell lines had significant expression of SDF-1 and CXCR4 (SDF-1 receptor). Treatment of osteosarcoma cells with SDF-1alpha increased the migration and cell surface expression of alphavbeta3 integrin. CXCR4-neutralizing antibody, CXCR4 specific inhibitor (AMD3100) or small interfering RNA against CXCR4 inhibited the SDF-1alpha-induced increase the migration and integrin expression of osteosarcoma cells. Pretreated of osteosarcoma cells with MAPK kinase (MEK) inhibitor PD98059 inhibited the SDF-1alpha-mediated migration and integrin expression. Stimulation of cells with SDF-1alpha increased the phosphorylation of MEK and extracellular signal-regulating kinase (ERK). In addition, NF-kappaB inhibitor (PDTC) or IkappaB protease inhibitor (TPCK) also inhibited SDF-1alpha-mediated cell migration and integrin up-regulation. Stimulation of cells with SDF-1alpha induced IkappaB kinase (IKKalpha/beta) phosphorylation, IkappaB phosphorylation, p65 Ser(536) phosphorylation, and kappaB-luciferase activity. Furthermore, the SDF-1alpha-mediated increasing kappaB-luciferase activity was inhibited by AMD3100, PD98059, PDTC and TPCK or MEK1, ERK2, IKKalpha and IKKbeta mutants. Taken together, these results suggest that the SDF-1alpha acts through CXCR4 to activate MEK and ERK, which in turn activates IKKalpha/beta and NF-kappaB, resulting in the activations of alphavbeta3 integrins and contributing the migration of human osteosarcoma cells.

Glial cell-derived neurotrophic factor increases migration of human chondrosarcoma cells via ERK and NF-kappaB pathways.

Invasion of tumor cells is the primary cause of therapeutic failure in the treatment of malignant chondrosarcomas. Glial cell-derived neurotrophic factor (GDNF) plays a crucial role in migration and metastasis of human cancer cells. Integrins are the major adhesive molecules in mammalian cells. Here we found that GDNF directed the migration and increased cell surface expression of alphav and beta3 integrin in human chondrosarcoma cells. Pretreated of JJ012 cells with MAPK kinase (MEK) inhibitors PD98059 or U0126 inhibited the GDNF-mediated migration and integrin expression. Stimulation of cells with GDNF increased the phosphorylation of MEK and extracellular signal-regulating kinase (ERK). In addition, NF-kappaB inhibitor (PDTC) or IkappaB protease inhibitor (TPCK) also inhibited GDNF-mediated cells migration and integrin up-regulation. Stimulation of cells with GDNF induced IkappaB kinase (IKKalpha/beta) phosphorylation, IkappaB phosphorylation, p65 Ser(536) phosphorylation, and kappaB-luciferase activity. Furthermore, the GDNF-mediated increasing of kappaB-luciferase activity was inhibited by PD98059, U0126, PDTC and TPCK or MEK, ERK, IKKalpha, and IKKbeta mutants. Taken together, these results suggest that the GDNF acts through MEK/ERK, which in turn activates IKKalpha/beta and NF-kappaB, resulting in the activations of alphavbeta3 integrin and contributing the migration of human chondrosarcoma cells.

CTGF enhances migration and MMP-13 up-regulation via alphavbeta3 integrin, FAK, ERK, and NF-kappaB-dependent pathway in human chondrosarcoma cells.

Tumor malignancy is associated with several features such as proliferation ability and frequency of metastasis. Connective tissue growth factor (CTGF), a secreted protein that binds to integrins, modulates the invasive behavior of certain human cancer cells. However, the effect of CTGF on migration activity in human chondrosarcoma cells is mostly unknown. Here we found that CTGF increased the migration and expression of matrix metalloproteinase (MMP)-13 in human chondrosarcoma cells (JJ012 cells). RGD peptide, alphavbeta3 monoclonal antibody (mAb) and MAPK kinase (MEK) inhibitors (PD98059 and U0126) but not RAD peptide inhibited the CTGF-induced increase of the migration and MMP-13 up-regulation of chondrosarcoma cells. CTGF stimulation increased the phosphorylation of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK). In addition, treatment of JJ012 cells with NF-kappaB inhibitor (PDTC) or IkappaB protease inhibitor (TPCK) inhibited CTGF-induced cell migration and MMP-13 up-regulation. Stimulation of JJ012 cells with CTGF also induced IkappaB kinase alpha/beta (IKK alpha/beta) phosphorylation, IkappaBalpha phosphorylation, p65 Ser(536) phosphorylation, and kappaB-luciferase activity. The CTGF-mediated increases in kappaB-luciferase activities were inhibited by RGD, PD98059, U0126 or FAK, and ERK2 mutant. Taken together, our results indicated that CTGF enhances the migration of chondrosarcoma cells by increasing MMP-13 expression through the alphavbeta3 integrin, FAK, ERK, and NF-kappaB signal transduction pathway.

Association of Resistin Gene Polymorphisms with Oral Squamous Cell Carcinoma Progression and Development.

Oral squamous cell carcinoma (OSCC) accounts for over 90% of malignant neoplasms of the mouth. In Taiwan, OSCC is the fourth most common male cancer and the fourth leading cause of male cancer death. Resistin (RETN) is an adipokine that is associated with obesity, inflammation, and various cancers. Here, we examine the association between four single nucleotide polymorphisms (SNPs) of the RETN gene (rs3745367, rs7408174, rs1862513, and rs3219175) and OSCC susceptibility as well as clinical outcomes in 935 patients with OSCC and in 1200 cancer-free healthy controls. We found that, in 1465 smokers, RETN polymorphisms carriers with the betel-nut chewing habit had a 6.708-10.882-fold greater risk of having OSCC compared to RETN wild-type carriers without the betel-nut chewing habit. Patients with OSCC who had A/A homozygous of RETN rs3219175 polymorphism showed a high risk for an advanced tumor size (> T2), compared to those patients with G/G homozygotes. In addition, A/T/G/G haplotype significantly increased the risks for OSCC by 1.376-fold. This study is the first to examine the risk factors associated with RETN SNPs in OSCC progression and development in Taiwan.