microRNA (miRNA) dysregulation contributes widely to human cancer but has not been fully assessed in oral cancers. In this study, we conducted a global microarray analysis of miRNA expression in 40 pairs of betel quid-associated oral squamous cell carcinoma (OSCC) specimens and their matched nontumorous epithelial counterparts. Eighty-four miRNAs were differentially expressed in the OSCC specimens compared with the matched tissue. Among these downregulated miRNAs, 19 miRNAs were found and mapped to the chromosome 14q32.2 miRNA cluster region, which resides within a parentally imprinted region designated as Dlk-Dio3 and known to be important in development and growth. Bioinformatic analysis predicted two miRNAs from the cluster region, miR329 and miR410, which could potentially target Wnt-7b, an activator of the Wnt-b-catenin pathway, thereby attenuating the Wnt-b-catenin signaling pathway in OSCC. Stable ectopic expression of Wnt-7b in OSCC cells overexpressing miR329 or miR410 restored proliferation and invasion capabilities abolished by these miRNA. Combining a demethylation agent and a histone deacetylase inhibitor was sufficient to reexpress miR329, miR410, and Meg3, consistent with epigenetic regulation of these miRNA in human OSCC. Specifically, arecoline, a major betel nut alkaloid, reduced miR329, miR410, and Meg3 gene expression. Overall, our results provide novel molecular insights into how betel quid contributes to oral carcinogenesis through epigenetic silencing of tumor-suppressor miRNA that targets Wnt-b-catenin signaling. Cancer Res; 74(24); 7560-72. Ó2014 AACR.

No abstract

Constitutively activated signal transducers and activators of transcription (STAT) factors, in particular STAT1, STAT3 and STAT5, have been demonstrated in a variety of human tumours and cancer cell lines. However, data on the expression of these STATs in nasopharyngeal carcinoma (NPC) are limited. In this study, the expression patterns of STAT1, STAT3 and STAT5 were immunohistochemically examined on the archival specimens from 61 patients with NPC. Staining results of each STATs were then correlated with the clinical parameters and prognosis of these patients. The results showed that constitutive activation of STAT3 and STAT5 was detected in the majority, 70.5 and 62.3%, respectively, of the 61 tumour specimens. Furthermore, coexpression of activated STAT3 and STAT5 was found in 54.1% of the specimens. In contrast, constitutive activated STAT1 could only be detected in 8 (13.1%) cases. Surprisingly, following radiotherapy, patients with constitutive STAT5 activation, or activation of both STAT3 and STAT5, had better disease-free survival and overall survival than those without activated STAT5. To our knowledge, this is the first report providing the overall expression patterns and prognostic significance of specific STATs in NPC.

Frequent metastasis to the cervical lymph nodes leads to poor survival of patients with oral squamous cell carcinoma (OSCC). To understand the underlying mechanisms of lymph node metastasis, two sublines were successfully isolated from cervical lymph nodes of nude mice through in vivo selection, and identified as originating from poorly metastatic parental cells. These two sublines specifically metastasized to cervical lymph nodes in 83% of mice, whereas OEC-M1 cells did not metastasize after injection into the oral cavity. After gene expression analysis, we identified insulin-like growth factor binding protein 3 (IGFBP3) as one of the significantly up-regulated genes in the sublines in comparison with their parental cells. Consistently, meta-analysis of the public microarray datasets and IGFBP3 immunohistochemical analysis revealed increased both levels of IGFBP3 mRNA and protein in human OSCC tissues when compared to normal oral or adjacent nontumorous tissues. Interestingly, the up-regulated IGFBP3 mRNA expression was significantly associated with OSCC patients with lymph node metastasis. IGFBP3 knockdown in the sublines impaired and ectopic IGFBP3 expression in the parental cells promoted migration, transendothelial migration and lymph node metastasis of orthotopic transplantation. Additionally, ectopic expression of IGFBP3 with an IGF-binding defect sustained the IGFBP3-enhanced biological functions. Results indicated that IGFBP3 regulates metastasis-related functions of OSCC cells through an IGF-independent mechanism. Furthermore, exogenous IGFBP3 was sufficient to induce cell motility and extracellular signal-regulated kinase (ERK) activation. The silencing of integrin β1 was able to impair exogenous IGFBP3-mediated migration and ERK phosphorylation, suggesting a critical role of integrin β1 in IGFBP3-enchanced functions.

Peptide-29 selected from biopanning may have clinical potential for HNSCC.

Therapeutic, III.

Paclitaxel activated cell cycle arrest and caspase protein expressions to induce apoptosis in HNSCC cell lines.

Growth differentiation factor-10 (GDF10), commonly referred as BMP3b, is a member of the transforming growth factor-β (TGF-β) superfamily. GDF10/BMP3b has been considered as a tumor suppressor, however, little is known about the molecular mechanism of its roles in tumor suppression in oral cancer. Clinical significance of GDF10 downregulation in oral squamous cell carcinoma (OSCC) was evaluated using three independent cohorts of OSCC patients. The molecular mechanisms of GDF10 in the suppression of cell survival, cell migration/invasion and epithelial-mesenchymal transition (EMT) were investigated by using oral cancer cell lines. The present study shows that GDF10 is downregulated during oral carcinogenesis, and GDF10 expression is also an independent risk factor for overall survival of OSCC patients. Overexpression of GDF10 attenuates cell proliferation, transformation, migration/invasion, and EMT. GDF10-inhibited EMT is mediated by ERK signaling but not by typical TGF-β signaling. In addition, overexpression of GDF10 promotes DNA damage-induced apoptosis and sensitizes the response to all-trans retinoic acid (ATRA) and camptothecin (CPT). Intriguingly, the expression of GDF10 is induced by type III TGF-β receptor (TGFBR3) through TGF-β-SMAD2/3 signaling. Our findings suggest that TGFBR3 is an upstream activator of GDF10 expression and they share the same signaling to inhibit EMT and migration/invasion. These results support that GDF10 acts as a hinge to collaborate with TGFBR3 in the transition of EMT-MET program. Taken together, we illustrated the clinical significance and the molecular mechanisms of tumor-suppressive GDF10 in OSCC.