Ras activation mediates WISP-1-induced increases in cell motility and matrix metalloproteinase expression in human osteosarcoma

WISP-1 is a cysteine-rich protein that belongs to the CCN (Cyr61, CTGF, Nov) family of matrix cellular proteins. Osteosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. However, the effect of WISP-1 on migration activity in human osteosarcoma cells is mostly unknown. In this study, we first found that the expression of WISP-1 in osteosarcoma patients was significantly higher than that in normal bone and corrected with tumor stage. Exogenous treatment of osteosarcoma cells with WISP-1 promoted cell motility and matrix metalloproteinase (MMP)-2 and MMP-9 expression. In addition, the Ras and Raf-1 inhibitor or siRNA abolished WISP-1-induced cell migration and MMP expression. On the other hand, activation of the Ras, Raf-1, MEK, ERK, and NF-κB signaling pathway after WISP-1 treatment was demonstrated, and WISP-1-induced expression of MMPs and migration activity were inhibited by the specific inhibitor, and mutant of MEK, ERK, and NF-κB cascades. Taken together, our results indicated that WISP-1 enhances the migration of osteosarcoma cells by increasing MMP-2 and MMP-9 expression through the integrin receptor, Ras, Raf-1, MEK, ERK, and NF-κB signal transduction pathway.     

CCN3 increases cell motility and MMP-13 expression in human chondrosarcoma through integrin-dependent pathway

Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. CCN3, also called nephroblastoma overexpressed gene (NOV), regulates proliferation and differentiation of cancer cells. However, the effect of CCN3 on migration activity in human chondrosarcoma cells is mostly unknown. Here, we found that CCN3 increased the migration and expression of matrix metalloproteinase (MMP)-13 in human chondrosarcoma cells (JJ012 cells). αvβ3 or αvβ5 monoclonal antibody (mAb), phosphatidylinositol 3-kinase (PI3K) inhibitors (Ly294002 and wortmannin) and Akt inhibitor inhibited the CCN3-induced increase of the migration and MMP-13 upregulation of chondrosarcoma cells. CCN3 stimulation increased the phosphorylation of focal adhesion kinase (FAK), PI3K, and Akt. In addition, NF-κB inhibitors also suppressed the cell migration and MMP-13 expression enhanced by CCN3. Moreover, CCN3 increased NF-κB luciferase activity and binding of p65 to the NF-κB element on the MMP-13 promoter. Taken together, our results indicate that CCN3 enhances the migration of chondrosarcoma cells by increasing MMP-13 expression through the αvβ3/αvβ5 integrin receptor, FAK, PI3K, Akt, p65, and NF-κB signal transduction pathway.     

Endothelin-1 promotes MMP-13 production and migration in human chondrosarcoma cells through FAK/PI3K/Akt/mTOR pathways

Tumor malignancy is associated with several cellular properties including proliferation and ability to metastasize. Endothelin-1 (ET-1) the most potent vasoconstrictor plays a crucial role in migration and metastasis of human cancer cells. We found that treatment of human chondrosarcoma (JJ012 cells) with ET-1 increased migration and expression of matrix metalloproteinase (MMP)-13. ET-1-mediated cell migration and MMP-13 expression were reduced by pretreatment with inhibitors of focal adhesion kinase (FAK), phosphatidylinositol 3-kinase (PI3K), Akt, and mammalian target of rapamycin (mTOR), as well as the NF-κB inhibitor and the IκB protease inhibitor. In addition, ET-1 treatment induced phosphorylation of FAK, PI3K, AKT, and mTOR, and resulted in increased NF-κB-luciferase activity that was inhibited by a specific inhibitor of PI3K, Akt, mTOR, and NF-κB cascades. Taken together, these results suggest that ET-1 activated FAK/PI3K/AKT/mTOR, which in turn activated IKKα/β and NF-κB, resulting in increased MMP-13 expression and migration in human chondrosarcoma cells.     

Cyr61 increases matrix metalloproteinase-3 expression and cell motility in human oral squamous cell carcinoma cells

Oral squamous cell carcinoma (OSCC) has a striking tendency to migrate and metastasize. 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 effects of Cyr61 on human OSCC cells are largely unknown. In this study, we found that Cyr61 increased the migration and the expression of matrix metalloproteinases-3 (MMP)-3 in human OSCC cells. αvβ5 or α6β1 monoclonal antibody (mAb), focal adhesion kinase (FAK) inhibitor, and mitogen-activated protein kinase (MEK) inhibitors (PD98059 and U0126) inhibited the Cyr61-induced increase of the migration and MMP-3 up-regulation of OSCC cells. Cyr61 stimulation increased the phosphorylation of FAK, MEK, and extracellular signal-regulated kinase (ERK). In addition, NF-κB inhibitors suppressed the cell migration and MMP-3 expression enhanced by Cyr61. Moreover, Cyr61 increased NF-κB luciferase activity and binding of p65 to the NF-κB element on the MMP-3 promoter. Taken together, our results indicate that Cyr61 enhances the migration of OSCC cells by increasing MMP-3 expression through the αvβ3 or α6β1 integrin receptor, FAK, MEK, ERK, and NF-κB signal transduction pathway.     

CCN6 enhances ICAM-1 expression and cell motility in human chondrosarcoma cells

Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. CCN6 is a cysteine-rich protein that belongs to the CCN (Cyr61, CTGF, and Nov) family of matricellular proteins. However, the effects of CCN6 on human chondrosarcoma cells are largely unknown. In this study, we found that CCN6 increased the migration and the expression of intercellular adhesion molecule-1 (ICAM-1) in human chondrosarcoma cells. αvβ3 and αvβ5 integrin monoclonal antibody and mitogen-activated protein kinase (MEK) inhibitors (PD98059 and U0126) inhibited the CCN6-induced increase of the migration and ICAM-1 up-regulation of chondrosarcoma cells. CCN6 stimulation increased the phosphorylation of focal adhesion kinase (FAK), MEK, and extracellular signal-regulated kinase (ERK). In addition, activator protein-1 (AP-1) inhibitors suppressed the cell migration and ICAM-1 expression enhanced by CCN6. Moreover, CCN6 increased AP-1 luciferase activity and binding of c-Jun to the AP-1 element on the ICAM-1 promoter. Taken together, our results indicate that CCN6 enhances the migration of chondrosarcoma cells by increasing ICAM-1 expression through the αvβ3 and αvβ5 integrin receptor, FAK, MEK, ERK, c-Jun, and AP-1 signal transduction pathway.     

TNF‐α increases αvβ3 integrin expression and migration in human chondrosarcoma cells

Chondrosarcoma is a type of highly malignant tumour with a potent capacity to invade locally and cause distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. Tumour necrosis factor (TNF)‐α is a key cytokine involved in inflammation, immunity, cellular homeostasis and tumour progression. Integrins are the major adhesive molecules in mammalian cells and have been associated with metastasis of cancer cells. However, the effects of TNF‐α in migration and integrin expression in chondrosarcoma cells are largely unknown. In this study, we found that TNF‐α increased the migration and the expression of αvβ3 integrin in human chondrosarcoma cells. Activations of MAPK kinase (MEK), extracellular signal‐regulating kinase (ERK) and nuclear factor‐κB (NF‐κB) pathways after TNF‐α treatment were demonstrated, and TNF‐α‐induced expression of integrin and migration activity was inhibited by the specific inhibitor and mutant of MEK, ERK and NF‐κB cascades. Taken together, our results indicated that TNF‐α enhances the migration of chondrosarcoma cells by increasing αvβ3 integrin expression through the MEK/ERK/NF‐κB signal transduction pathway. J. Cell. Physiol. 226: 792–799, 2011. © 2010 Wiley‐Liss, Inc.     

IGF-I enhances α5β1 integrin expression and cell motility in human chondrosarcoma cells

Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. Integrins are the major adhesive molecules in mammalian cells and have been associated with metastasis of cancer cells. Insulin-like growth factor-I (IGF)-I plays an important role in regulating cell growth, proliferation, survival, and metabolism. However, the effects of IGF-I in migration and integrin expression in chondrosarcoma cells are largely unknown. In this study, we found that IGF-I increased the migration and the expression of α5β1 integrin in human chondrosarcoma cells. Pretreatment of cells with IGF-I receptor antibody reduced IGF-I-induced cell migration and integrin expression. Activations of phosphatidylinositol 3-kinase (PI3K), Akt, and nuclear factor-κB (NF-κB) pathways after IGF-I treatment were demonstrated, and IGF-I-induced expression of integrin and migration activity was inhibited by the specific inhibitor and mutant of PI3K, Akt, and NF-κB cascades. Taken together, our results indicated that IGF-I enhances the migration of chondrosarcoma cells by increasing α5β1 integrin expression through the IGF-I receptor/PI3K/Akt/NF-κB signal transduction pathway.     

Macrophage migration inhibitory factor increases cell motility and up-regulates αvβ3 integrin in human chondrosarcoma cells

The macrophage migration-inhibitory factor (MIF) is a pro-inflammatory cytokine first known for its effect on macrophage migration and activation. Recent studies have shown that MIP plays a critical role in tumor growth, angiogenesis, and metastasis. Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. However, the effects of MIF on human chondrosarcoma cells are largely unknown. In the present study, MIF was found to increase the migration and the expression of αvβ3 integrin in human chondrosarcoma cells. The phosphatidylinositol 3-kinase (PI3K), Akt, and NF-κB pathways were activated by MIF treatment, and the MIF-induced expression of integrin and migration activity were inhibited by the specific inhibitors and mutant forms of PI3K, Akt, and NF-κB cascades. In addition, migration-prone sublines demonstrated that increased cell migration ability was correlated with increased expression of MIF and αvβ3 integrin. Taken together, our results indicate that MIF enhanced the migration of the chondrosarcoma cells by increasing αvβ3 integrin expression through the PI3K/Akt/NF-κB signal transduction pathway.     

CTGF enhances migration and MMP‐13 up‐regulation via αvβ3 integrin,FAK, ERK,and NF‐κB‐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, αvβ3 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‐κB inhibitor (PDTC) or IκB protease inhibitor (TPCK) inhibited CTGF‐induced cell migration and MMP‐13 up‐regulation. Stimulation of JJ012 cells with CTGF also induced IκB kinase α/β (IKK α/β) phosphorylation, IκBα phosphorylation, p65 Ser⁵³⁶ phosphorylation, and κB‐luciferase activity. The CTGF‐mediated increases in κB‐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 αvβ3 integrin, FAK, ERK, and NF‐κB signal transduction pathway. J. Cell. Biochem. 107: 345–356, 2009. © 2009 Wiley‐Liss, Inc.     

RANKL increases migration of human lung cancer cells through intercellular adhesion molecule-1 up-regulation

Invasion of distant tissues by tumor cells is the primary cause of therapeutic failure in the treatment of malignant lung cancer cells. Receptor activator of nuclear factor-κB ligand (RANKL) and its receptor, RANK, play a key role in osteoclastogenesis and tumor metastasis. Intercellular adhesion molecule-1 (ICAM-1, also called CD54), a member of the immunoglobulin supergene family, is an inducible surface glycoprotein that mediates adhesion-dependent cell-to-cell interactions. The effects of RANKL on cell migration and ICAM-1 expression in human lung cancer cells are largely unknown. We found that RANKL directed the migration and increased ICAM-1 expression in human lung cancer (A549) cells. Pretreatment of A549 cells with the MAPK kinase (MEK) inhibitor PD98059 or U0126 inhibited RANKL-mediated migration and ICAM-1 expression. Stimulation of cells with RANKL increased the phosphorylation of MEK and extracellular signal-regulating kinase (ERK). In addition, an NF-κB inhibitor (PDTC) and IκB protease inhibitor (TPCK) also inhibited RANKL-mediated cell migration and ICAM-1 up-regulation. Taken together, these results suggest that the RANKL and RANK interaction acts through MEK/ERK, which in turn activates NF-κB, resulting in the activation of ICAM-1 and contributing to the migration of human lung cancer cells.     

Glial cell‐derived neurotrophic factor increases migration of human chondrosarcoma cells via ERK and NF‐κB 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 αv and β3 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‐κB inhibitor (PDTC) or IκB protease inhibitor (TPCK) also inhibited GDNF‐mediated cells migration and integrin up‐regulation. Stimulation of cells with GDNF induced IκB kinase (IKKα/β) phosphorylation, IκB phosphorylation, p65 Ser⁵³⁶ phosphorylation, and κB‐luciferase activity. Furthermore, the GDNF‐mediated increasing of κB‐luciferase activity was inhibited by PD98059, U0126, PDTC and TPCK or MEK, ERK, IKKα, and IKKβ mutants. Taken together, these results suggest that the GDNF acts through MEK/ERK, which in turn activates IKKα/β and NF‐κB, resulting in the activations of αvβ3 integrin and contributing the migration of human chondrosarcoma cells. J. Cell. Physiol. 220: 499–507, 2009. © 2009 Wiley‐Liss, Inc.     

Involvement of integrin up‐regulation in RANKL/RANK pathway of chondrosarcomas migration

Invasion of tumor cells is the primary cause of therapeutic failure in malignant chondrosarcomas treatment. Receptor activator of nuclear factor‐κB ligand (RANKL) and its receptor, RANK, play a key roles in osteoclastogenesis and tumor metastasis. We found that the RANKL and RANK expression in human chondrosarcoma tissues was higher than that in normal cartilage. We also found that RANKL directed the migration and increased cell surface expression of β1 integrin in human chondrosarcoma cells (JJ012 cells). Pretreatment of JJ012 cells with MAPK kinase (MEK) inhibitors, PD98059 or U0126, inhibited the RANKL‐induced migration and integrin expression. Stimulation of cells with RANKL increased the phosphorylation of MEK and extracellular signal‐regulating kinase (ERK). In addition, NF‐κB inhibitor (PDTC) or IκB protease inhibitor (TPCK) also inhibited RANKL‐induced cells migration and integrin up‐regulation. Taken together, these results suggest that the RANKL acts through MEK/ERK, which in turn activates IKKα/β and NF‐κB, resulting in the activation of β1 integrin and contributing to the migration of human chondrosarcoma cells. J. Cell. Biochem. 111: 138–147, 2010. © 2010 Wiley‐Liss, Inc.     

HGF and c-Met Interaction Promotes Migration in Human Chondrosarcoma Cells

Chondrosarcoma is a type of highly malignant tumor with a potent capacity for local invasion and causing distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. Hepatocyte growth factor (HGF) has been demonstrated to stimulate cancer proliferation, migration, and metastasis. However, the effect of HGF on migration activity of human chondrosarcoma cells is not well known. Here, we found that human chondrosarcoma tissues demonstrated significant expression of HGF, which was higher than that in normal cartilage. We also found that HGF increased the migration and expression of matrix metalloproteinase (MMP)-2 in human chondrosarcoma cells. c-Met inhibitor and siRNA reduced HGF-increased cell migration and MMP-2 expression. HGF treatment resulted in activation of the phosphatidylinositol 3′-kinase (PI3K)/Akt/PKCδ/NF-κB pathway, and HGF-induced expression of MMP-2 and cell migration was inhibited by specific inhibitors or siRNA-knockdown of PI3K, Akt, PKCδ, and NF-κB cascades. Taken together, our results indicated that HGF enhances migration of chondrosarcoma cells by increasing MMP-2 expression through the c-Met receptor/PI3K/Akt/PKCδ/NF-κB signal transduction pathway.     

IL-8 increases integrin expression and cell motility in human chondrosarcoma cells

Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. Interleukin-8 (IL-8), a chemokine with a defining CXC amino acid motif, is known to possess tumorigenic and proangiogenic properties. Over-expression of IL-8 has been detected in many human tumors. However, the effects of IL-8 in migration and integrin expression in chondrosarcoma cells are largely unknown. In this study, we found that IL-8 increased the migration and the expression of αvβ3 integrin in human chondrosarcoma cells. Activations of phosphatidylinositol 3-kinase (PI3K), Akt, and AP-1 pathways after IL-8 treatment were demonstrated, and IL-8-induced expression of integrin and migration activity was inhibited by the specific inhibitor and mutant of PI3K, Akt, and AP-1 cascades. Taken together, our results indicated that IL-8 enhances the migration of chondrosarcoma cells by increasing αvβ3 integrin expression through the PI3K/Akt/AP-1 signal transduction pathway.     

Exogenous interleukin-1 beta promotes the proliferation and migration of HeLa cells via the MEK/ERK signaling pathway

Objective

Interleukin-1 beta (IL-1β) is a crucial cytokine that has been implicated in cancer and metastasis development. However, its possible mechanistic role in cervical cancer remains unclear. This study aimed to investigate the functions of exogenous IL-1β in cervical cancer cell proliferation and migration.

Methods

HeLa cell proliferation and migration were measured using MTT and Transwell assays. A lentivirus-mediated packaging system was used to construct an IL-1β overexpressing cell line. MEK/ERK signal transduction was inhibited by pretreatment with the MEK inhibitor PD98059. qRT–PCR and Western blotting were used to test the expression of relevant genes.

Results

Exogenous IL-1β promoted the proliferation and migration of HeLa cells. In addition, overexpression of IL-1β in HeLa cells promoted cell proliferation. Mechanistically, exogenous IL-1β increased the phosphorylated MEK and ERK levels in HeLa cells and the expression of JUN, RELB, and NF-κB2. Alternatively, blockade of MEK inhibited the promoting proliferation effects of IL-1β and the expression of JUN, RELB, and NF-κB2.

Conclusions

Our data suggest that exogenous IL-1β regulates HeLa cell functions by regulating the MEK/ERK signaling pathway and by targeting JUN, RELB, and NF-κB2. Our study uncovered a potential association across IL-1β, cervical tumor development, and cancer progression.

     

Oligonol, an oligomerized lychee fruit-derived polyphenol, activates the Ras/Raf-1/MEK1/2 cascade independent of the IL-6 signaling pathway in rat primary adipocytes

Oligonol is a lychee fruit-derived low-molecular form of polyphenol. In this study, the effect of Oligonol on the mitogen activated-protein kinase (MAPK) signaling pathway in primary adipocytes was investigated to examine the mechanism underlying the enhanced levels of phosphorylated extracellular-signaling regulatory kinase1/2 (ERK1/2) that accompany an in vitro increase in lipolysis. Oligonol significantly elevated the levels of activated Ras and the phosphorylation of Raf-1 and MAPK/ERK kinase1/2 (MEK1/2) with no increase in pan-Raf-1 and -MEK1/2 proteins. The increase in phosphorylation of Raf-1 and MEK1/2 with Oligonol was inhibited completely by pretreatment with GW5074, a selective Raf-1 inhibitor, or PD98059, a selective MEK1/2 inhibitor. IL-6 also activated the MAPK signaling pathway in adipocytes through the association with its receptor. IL-6-induced phosphorylation of Raf-1 and MEK1/2 was significantly inhibited by pretreatment with the IL-6 receptor antibody. Under such a condition, however, the levels of phosphorylated Raf-1 and MEK1/2 with Oligonol still remained significantly higher, and there was a significant decrease in secretion of IL-6 from adipocytes, compared with untreated control cells. These results suggest that Oligonol activates the Ras/Raf-1/MEK1/2 signaling pathway, independent of the IL-6 signaling pathway, leading to activation of ERK1/2 proteins in primary adipocytes.     

Thrombin-induced NF-κB activation and IL-8/CXCL8 release is mediated by c-Src-dependent Shc,Raf-1, and ERK pathways in lung epithelial cells

In addition to its functions in thrombosis and hemostasis, thrombin also plays an important role in lung inflammation. Our previous report showed that thrombin activates the protein kinase C (PKC)α/c-Src and Gβγ/Rac1/PI3K/Akt signaling pathways to induce IκB kinase α/β (IKKα/β) activation, NF-κB transactivation, and IL-8/CXCL8 expressions in human lung epithelial cells (ECs). In this study, we further investigated the mechanism of c-Src-dependent Shc, Raf-1, and extracellular signal-regulated kinase (ERK) signaling pathways involved in thrombin-induced NF-κB activation and IL-8/CXCL8 release. Thrombin-induced increases in IL-8/CXCL8 release and κB-luciferase activity were inhibited by the Shc small interfering RNA (siRNA), p66Shc siRNA, GW 5074 (a Raf-1 inhibitor), and PD98059 (a mitogen-activated protein kinase (MAPK) kinase (MEK) inhibitor). Treatment of A549 cells with thrombin increased p66Shc and p46/p52Shc phosphorylation at Tyr239/240 and Tyr317, which was inhibited by cell transfection with the dominant negative mutant of c-Src (c-Src DN). Thrombin caused time-dependent phosphorylation of Raf-1 and ERK, which was attenuated by the c-Src DN. Thrombin-induced IKKα/β phosphorylation was inhibited by GW 5074 and PD98059. Treatment of cells with thrombin induced Gβγ, c-Src, and p66Shc complex formation in a time-dependent manner. Taken together, these results show for the first time that thrombin activates Shc, Raf-1, and ERK through Gβγ, c-Src, and Shc complex formation to induce IKKα/β phosphorylation, NF-κB activation, and IL-8/CXCL8 release in human lung ECs.     

Osteopontin increases migration and MMP‐9 up‐regulation via αvβ3 integrin,FAK, ERK,and NF‐κB‐dependent pathway in human chondrosarcoma cells

Tumor malignancy is associated with several features such as proliferation ability and frequency of metastasis. Osteopontin (OPN), which abundantly expressed in bone matrix, is involved in cell adhesion, migration, invasion and proliferation via interaction with its receptor, that is, αvβ3 integrin. However, the effect of OPN on migration activity in human chondrosarcoma cells is mostly unknown. Here we found that OPN increased the migration and expression of matrix metalloproteinase (MMP)‐9 in human chondrosarcoma cells (JJ012 cells). RGD peptide, αvβ3 monoclonal antibody and MAPK kinase (MEK) inhibitors (PD98059 and U0126) but not RAD peptide inhibited the OPN‐induced increase of the migration and MMP‐9 up‐regulation of chondrosarcoma cells. OPN stimulation increased the phosphorylation of focal adhesion kinase (FAK), MEK and extracellular signal‐regulated kinase (ERK). In addition, treatment of JJ012 cells with NF‐κB inhibitor (PDTC) or IκB protease inhibitor (TPCK) inhibited OPN‐induced cell migration and MMP‐9 up‐regulation. Stimulation of JJ012 cells with OPN also induced IκB kinase α/β (IKK α/β) phosphorylation, IκBα phosphorylation, p65 Ser⁵³⁶ phosphorylation, and κB‐luciferase activity. The OPN‐mediated increases in MMP‐9 and κB‐luciferase activities were inhibited by RGD peptide, PD98059 or FAK and ERK2 mutant. Taken together, our results indicated that OPN enhances the migration of chondrosarcoma cells by increasing MMP‐9 expression through the αvβ3 integrin, FAK, MEK, ERK and NF‐κB signal transduction pathway. J. Cell. Physiol. 221: 98–108, 2009. © 2009 Wiley‐Liss, Inc