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Background: Sonic hedgehog (SHH) signaling is related to the pathogenesis of oral squamous cell carcinoma (OSCC), but its role in OSCC is not yet well understood. In this study, we analyzed the role of SHH signaling in OSCC., Materials and Methods: We examined the expression pattern of SHH and its signal proteins in clinically resected OSCC samples by immunohistochemistry. We also evaluated the function of SHH signaling using the hedgehog signaling inhibitor cyclopamine in vivo and in vitro by proliferation, migration and angiogenesis analyses., Results: We found that SHH was highly expressed in human tongue OSCC, whereas patched (PTCH1), glioma-associated oncogene 1 (GLI1) and GLI2 proteins were expressed in the microvascular cells in the tumor invasive front. Administration of cyclopamine to mice suppressed the growth and angiogenesis of OSCC xenografts in vivo. Moreover, cyclopamine inhibited endothelial cell proliferation and migration, and reduced aorta vascular length in the rat., Conclusion: These findings suggest that OSCC-derived SHH stimulates angiogenesis at the tumor invasive front., (Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Midkine is a heparin-binding growth factor highly expressed in various human malignant tumors. However, its role in the growth of oral squamous cell carcinoma is not well understood. In this study, we analyzed the antitumor effect of a novel midkine inhibitor (iMDK) against oral squamous cell carcinoma. Administration of iMDK induced a robust antitumor response and suppressed cluster of differentiation 31 (CD31) expression in oral squamous cell carcinoma HSC-2 cells and SAS cells xenograft models. iMDK inhibited the proliferation of these cells dose-dependently, as well as the expression of midkine and phospho-extracellular signal-regulated kinase in HSC-2 and SAS cells. Moreover, iMDK significantly inhibited vascular endothelial growth factor and induced tube growth of human umbilical vein endothelial cells in a dose-dependent fashion. These findings suggest that midkine is critically involved in oral squamous cell carcinoma and iMDK can be effectively used for the treatment of oral squamous cell carcinoma., (Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Background: Breast cancer cells frequently metastasize to the skeleton and produce and secrete proteinases, such as matrix metalloproteinase-13 (MMP-13), which promote destruction of the bone matrix. However, the mechanism of MMP-13 expression induced in areas of bone metastasis is unknown. Here, the interaction between tumors and type I collagen in bone metastasis was investigated., Materials and Methods: A mouse model of bone metastasis was prepared by inoculating mice with suspensions of cells of the human metastatic breast cancer cell line MDA-MB-231 via the left cardiac ventricle. MMP-13 expression was examined by immunohistochemical, Western blot, and real-time RT-PCR analyses., Results: MMP-13 expression was highly up-regulated in MDA-MB-231 cells, and attachment of these cells to type I collagen and the induction of MMP-13 were down-regulated by treatment with integrin α1, α2 or β1 neutralizing antibodies. The attachment of MDA-MB-231 cells to type I collagen induced the activation of focal adhesion kinase (FAK) and p38 mitogen-activated protein kinase (MAPK). Inhibition of FAK and p38 MAPK down-regulated type I collagen-induced MMP-13 expression., Conclusion: Our study indicates that metastatic breast cancer cells in the bone microenvironment attached to type I collagen, which stimulated integrins α1β1 and α2β1, via FAK and p38 MAPK pathways, to induce MMP13 expression and further osteolysis.

Heat-shock protein 90 (HSP90) is a major cellular chaperone protein. HSP90 supports the correct conformation, stabilization, activation, and localization of 'client' oncoproteins, many of which are involved in tumor progression. Therefore, the use of HSP90 inhibitors has become a new strategy in antitumor therapy. However, the effects of an HSP90 inhibitor on oral squamous cell carcinoma are still unclear. NVP-AUY922 (Novartis) is a novel 4,5-diaryloxazole adenosine triphosphate-binding site HSP90 inhibitor. In this study, we investigated the antitumor effect of novel HSP90 inhibitor NVP-AUY922 against oral squamous cell carcinoma. NVP-AUY922 inhibited the proliferation of oral squamous cell carcinoma cells in vitro. NVP-AUY922 caused degradation of client protein inducing ErbB2, p-Akt, p-S6, hypoxia-inducible factor 1-α (HIF1-α) and vascular endothelial growth factor (VEGF) and up-regulation of HSP70 in HSC-2 oral squamous cell carcinoma. NVP-AUY922 increased the expression of cleaved caspase-3 and induced apoptosis in HSC-2 cells. Treatment of NVP-AUY922 induced a robust antitumor response and suppressed p-Akt and VEGF expression in an HSC-2 xenograft model. In summary, NVP-AUY922 exhibits in vitro and in vivo efficiency against oral squamous cell carcinoma, representing a promising therapeutic approach for oral squamous cell carcinoma.

Background: Gingival squamous cell carcinoma (SCC) cells frequently invade mandibular bone, and this destruction is associated with a worse prognosis. However, the relationship between bone destruction and associated factors is unclear. In this study, the role and diagnostic utility of transforming growth factor-beta (TGF-beta) type I receptor (TbetaRI) in bone destruction of the mandible was investigated., Patients and Methods: The expression of TbetaRI was explored by using an immunohistochemical method on paraffin-embedded tissues from 21 cases of mandibular SCC. An inhibitor of the kinase activity of the TbetaRI (TbetaRI-I) was used to assess the role of TbetaRI in bone destruction by a human oral SCC cell line (HSC-2) that highly expresses TbetaRI., Results: TbetaRI-positive signals were closely associated with destructive invasion of the mandible by oral SCC cells. Consistent with these results, TbetaRI-I greatly reduced HSC-2 cell-induced bone destruction and osteoclast formation in vivo and in vitro. TbetaRI-I treatment reduced the expression of TNF-alpha, RANKL and connective tissue growth factor (CTGF/CCN2), all of which were up-regulated by TGF-beta in HSC-2 cells., Conclusion: These data demonstrated an important role for TGF-beta signalling in bone invasion by oral SCC cells, and suggest that the bone destruction is mediated by RANKL, TNF-alpha and CCN2.

Background: Parathyroid hormone-related protein (PTHrP) is a key regulator of osteolytic metastasis of breast cancer (BC) cells, but its targets and mechanisms of action are not fully understood. This study investigated whether/how PTHrP (1-34) signaling regulates expression of vascular endothelial growth factor (VEGF) produced by BC cells., Materials and Methods: A mouse model of bone metastasis was prepared by inoculating mice with tumour cell suspensions of the human BC cell line MDA-MB-231 via the left cardiac ventricle. VEGF expression was examined by Western blot and real-time RT-PCR analysis, as well as by confocal microscopy in the bone microenvironment., Results: PTHrP was expressed in cancer cells producing PTH/PTHrP receptor and VEGF that had invaded the bone marrow, and PTHrP was up-regulated VEGF in MDA-MB-231 in vitro. The culture medium conditioned by PTHrP-treated MDA-MB-231 cells stimulated angiogenesis and osteoclastogenesis compared with control medium, giving a response that was inhibited by VEGF-neutralizing antibody treatment. Inhibition of protein kinase C (PKC) prevented PTHrP-induced extracellular signal-regulated kinase (ERK1/2) and p38 activation, and PTHrP-induced VEGF expression., Conclusion: PTHrP plays an important role in modulating the angiogenic and bone osteolytic actions of VEGF through PKC-dependent activation of an ERK1/2 and p38 signaling pathway during bone metastasis by breast cancer cells.

Background: Mandibular bone destruction is a frequent occurrence in oral squamous cell carcinoma. However, the relationship between the bone destruction and associated factors is unclear. Here, the role and diagnostic utility of connective tissue growth factor (CCN2) in bone destruction of the mandible was investigated., Patients and Methods: The production of CCN2 was explored by using immunohistochemistry on paraffin-embedded tissues from 20 cases of mandibular squamous cell carcinoma. The effect of CCN2 on osteoclastogenesis was examined in vitro by using total bone marrow cell populations from male mice., Results: Immunohistochemical analysis showed that CCN2-positive signals were closely associated with destructive invasion of the mandible by oral squamous cell carcinomas. Consistent with these results, recombinant human CCN2 (rCCN2) stimulated tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like cell formation in vitro., Conclusion: CCN2 can be considered a diagnostic marker and target for treatment in oral osteolytic mandibular squamous cell carcinoma.