No abstract

The WW domain-containing oxidoreductase (WWOX) functions as a tumour suppressor in oral carcinogenesis. As aberrant TMEM207 expression may lead to tumour progression by hampering the tumour suppressor function of WWOX in various cancers, we explored the expression and pathobiological properties of TMEM207, focusing on the WWOX-mediated regulation of the HIF-1a pathway in oral squamous cell carcinoma (OSCC). TMEM207 immunoreactivity was detected in 40 of 90 OSCC samples but not in neighbouring non-tumorous epithelial tissues. Moreover, TMEM207 expression was significantly correlated with lymph node metastasis and poor prognosis. An in situ proximal ligation assay demonstrated the colocalization of TMEM207 and WWOX in invasive OSCC cells, especially glycogen-rich ones. Enforced expression of TMEM207 abrogated the binding of WWOX to HIF-1a, increased HIF-1a and GLUT-1 expression, even under normoxic conditions, and promoted tumour growth in a xenoplant assay using SAS tongue squamous cancer cells. In contrast, TMEM207 knockdown decreased GLUT-1 expression in two OSCC cell lines. As a whole, our findings indicate that the aberrant expression of TMEM207 contributes to tumour progression in OSCC, possibly via promoting aerobic glycolysis.

Purpose This study aimed to investigate the relationship between loss of AT-rich interactive domain-containing protein 1A (ARID1A) expression and the prognosis of patients with oral squamous cell carcinoma (OSCC). Methods Seventy-five OSCC tissue specimens were immunohistochemically stained with a specific antibody to ARID1A. The immunoreactivity of ARID1A was then correlated with clinicopathological factors, including the prognosis of the patients. Results Non-tumorous oral squamous cells exhibited nuclear ARID1A staining, whereas the invasive OSCC cells showed different degrees of loss of ARID1A immunoreactivity. Little-to-no ARID1A immunoreactivity was found at the cancer invasion front in 20 of the 75 OSCC tissue specimens, with significant association with unfavorable patient outcomes. Notably, downregulation of ARID1A immunoreactivity was also related to lymphovascular involvement and poor outcome in patients with T1 and T2 OSCC without lymph node metastasis. Conclusions The results suggest that loss of ARID1A expression at the cancer invasion front might be related to tumor progression in many OSCCs.

Overexpression of Cleft Lip and Palate Transmembrane 1-Like (Clptm1L) confers cancer cell survival through the endoplasmic reticulum (ER) stress survival signaling pathway, while TMEM207 impairs the tumor suppressor function of WW domain containing oxidoreductase (WWOX), which sensitizes cancer cells to ER stress-induced apoptosis. In the present study, we examined whether these two ER stress-related proteins, Clptm1L and TMEM207, could be prognostic markers in oral squamous cell carcinoma (OSCC). Immunohistochemical staining using specific antibodies to Clptm1L or TMEM207 revealed that 31 of 89 tissue specimens exhibited concomitant expression of Clptm1L and TMEM207 at the cancer invasion front. A Kaplan–Meier plot of the patient survival curve followed by a log-rank test revealed that the coexpression of Clptm1L and TMEM207 was significantly associated with poor outcome in patients with OSCC (P = 0.00252). Coexpression of Clptm1L and TMEM207 was closely related to lymph node metastasis (P=0.000574). Both univariate and multivariate analyses demonstrated that coexpression of Clptm1L and TMEM207 predicted the poor prognosis of the patients with OSCC. The present study indicated that the double positive Clptm1L and TMEM207 immunoreactivity was closely related to lymph node metastasis with prognostic value in patients with OSCC.