Hypoxia-Induced Cleavage Of Soluble ephrinA1 From Cancer Cells Is Mediated By MMP-2 And Associates With Angiogenesis In Oral Squamous Cell Carcinoma.

INTRODUCTION: ephrinA1 plays important roles in tumor angiogenesis. Matrix metalloproteases (MMPs) can cleave ephrinA1 from the cell membrane into extracellular environment. However, how soluble ephrinA1 is modulated by hypoxia and whether MMPs participate in this hypoxic process remains to be investigated in detail. METHODS: Thirty-seven patients with oral squamous cell carcinoma (OSCC) were included in the present study for HIF-1α, MMP-2, MMP-9 and ephrinA1 detection by immunohistochemistry. Serum samples from 35 patients were collected both preoperatively and postoperatively to confirm the existence of soluble ephrinA1 by ELISA. Block assay and Western blot analysis were further carried out to elucidate the proteolysis mechanism of ephrinA1 under hypoxic condition in vitro. RESULTS: Our data demonstrated that HIF-1α, MMP-2, MMP-9 and ephrinA1 expressed positively, and correlated with microvessel density in OSCCs, except for MMP-9. The serum expression level of ephrinA1 in OSCC patients decreased significantly after surgical removal of the solid tumors. In vitro experiments indicated that GM6001, a MMP-specific inhibitor, could reduce hypoxia-induced soluble ephrinA1 secretion from SCC cells. Further Western blot analysis confirmed that both HIF-1α and MMP-2 were up-regulated by hypoxia in a similar time-dependent manner, with the MMP-9 expression unchanged during this course. CONCLUSION: These results suggested a possible novel mechanism that ephrinA1 secretion is mediated by HIF-1α/MMP-2 signaling cascade which may play pivotal roles in OSCC neovascularization in a paracrine manner.

[The study of combined unilateral intraoral and extraoral reduction approach in the treatment of anterior temporo-mandibular joint dislocation].

OBJECTIVE: To observe the clinical outcomes of a combined unilateral intraoral and extraoral reduction approach in the treatment of anterior temporomandibular joint (TMJ) dislocation. METHODS: Postural muscular chains were utilized in the biomechanical analysis of stomatognathic systems for improving TMJ repositioning approaches. A total of 87 patients with anterior TMJ dislocation were included in the present study. A combined unilateral intraoral and extraoral reduction approach was applied, and the clinical effects were evaluated. RESULTS: Biomechanical analysis reveal that reflexive contrac-tion of the maxillary muscle group was blocked sufficiently during the combined unilateral intraoral and extraoral reduction process. All dislocated TMJs were set successfully and efficiently with few complications. CONCLUSIONS: Combined unilateral intraoral and extraoral reduction approach is an effective, convenient, and minimally invasive way to treat anterior TMJ dislo-cations.