Purpose:We investigated the role of candidate tumor suppressor and proapoptotic WOX1 (also named WWOX, FOR, or WWOXv1) in UVB-induced apoptosis and formation of cutaneous squamous cell carcinomas (SCC). Experimental Design: Expression of WOX1and family proteins (WWOX) in human primary cutaneous SCCs was examined by immunohistochemistry, in situ hybridization, and reverse transcription-PCR. UVB irradiation^induced WOX1 activation (Tyr 33 phosphorylation and nuclear translocation), apoptosis, and cutaneous SCC formation were examined both in vitro and in vivo. Results: Up-regulation of human WOX1, isoform WOX2, and Tyr 33 phosphorylation occurred during normal keratinocyte differentiation before cornification and death. Interestingly, significant reduction of these proteins and Tyr 33 phosphorylation was observed in nonmetastatic and metastatic cutaneous SCCs (P < 0.001), but without down-regulation of WWOX mRNA (P > 0.05 versus normal controls), indicating a translational blockade of WWOX mRNA to protein.During acute exposure of hairless mice to UVB, WOX1was up-regulated and activated in epidermal cells in 24 hours. In parallel with the clinical findings in humans, chronic UVB-treated mice developed cutaneous SCCs in 3 months, with significant reduction of WOX1 and Tyr 33 phosphorylation and, again, without down-regulation of WWOX mRNA. Human SCC-25 and HaCaT cells were transfected with small interfering RNA^targeting WOX1 and shown to resist UVBinduced WOX1 expression, activation, and apoptosis. Conclusions: WOX1 is essential for UVB-induced apoptosis and likely to be involved in the terminal differentiation of normal keratinocytes. During UVB-induced cutaneous SCC, epidermal cells have apparently prevented the apoptotic pressure from overexpressed WOX1 by shutting down the translation machinery for WWOX mRNA.

Independent and interactive effects related to the development of hepatocellular carcinoma were assessed using a community-based case-control study for hepatitis B virus, habitual alcohol drinking, cigarette smoking, peanut consumption and history of hepatocellular carcinoma among the immediate family. All 200 male newly diagnosed hepatocellular carcinoma patients were recruited consecutively through the period of study as the case group from two teaching medical centers in northern and southern Taiwan. Healthy community residents matched one-to-one with cases on age, sex, ethnic group and residential area were selected as the control group. The carrier status of HBsAg and HBeAg was determined by blind radioimmunoassays, and other risk factors were obtained through standardized interviews according to a structured questionnaire. Conditional logistic regression analysis showed a significant association between hepatocellular carcinoma and the carrier status of HBsAg and HBeAg with an odds ratio of 16.7 and 56.5, respectively, for carriers of HBsAg alone and for carriers of both HBsAg and HBeAg. There was a dose-response relationship between cigarette smoking and hepatocellular carcinoma with an odds ratio of 1.1, 1.5 and 2.6, respectively, for those who smoked 1 to 10, 11 to 20 and more than 20 cigarettes a day. A significant association with hepatocellular carcinoma was also observed for the habitual alcohol consumer with an odds ratio of 3.4. Those whose immediate family had a history of hepatocellular carcinoma were more likely to have the disease develop, with an odds ratio of 4.6. However, the frequency of peanut consumption was not significantly associated with hepatocellular carcinoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Background: Constitutive activation of signal transducer and activator of transcription 3 at tyrosine residue 705 (p-STAT3 (tyr705)) has been associated with many types of human cancers. However, its potential roles and biological effects in hepatocellular carcinoma (HCC) are not well established. Aim: To explore whether an altered p-STAT3 (tyr705) expression is associated with angiogenesis or proliferation and thereby plays a part in HCC development. Methods: Paraffin-wax-embedded sections from 69 patients with HCC were collected in this study. Using a semiquantitative immunohistochemical staining method, the expression patterns of p-STAT3 (tyr705) in both HCC lesions and the adjacent non-tumorous liver parenchyma were analysed. The results obtained were further correlated with intratumour microvessel density (MVD), Ki-67 expression, clinicopathological parameters and overall survival. Results: A strong p-STAT3 (tyr705) nuclear staining was observed in 49.3% of HCC lesions, but was reported only in 5.8% of the adjacent non-tumorous liver parenchyma (p,0.001). The expression of p-STAT3 (tyr705) in HCC lesions was significantly and positively correlated with the intratumour MVD (p = 0.002), but not with Ki-67 expression. No significant correlation of p-STAT3 (tyr705) was found in addition to histological grading (p = 0.019). Multivariate Cox regression analysis showed that p-STAT3 (tyr705) expression was a significant predictor of overall survival for HCC (p = 0.036), although the Kaplan-Meier survival curves showed no significant difference between the high and low p-STAT3 (tyr705) expression subgroups. Conclusions:The results showed that p-STAT3 (tyr705) expression was closely correlated with histological grading and intratumour MVD in HCC. Thus, the potential role of p-STAT3 (tyr705) in HCC development may be through these correlations.

Squamous cell carcinoma (SCC) cells refractory to initial chemotherapy frequently develop disease relapse and distant metastasis. We show here that tumor suppressor WW domain-containing oxidoreductase (WWOX) (also named FOR or WOX1) regulates the susceptibility of SCC to methotrexate (MTX) in vitro and cure of SCC in MTX therapy. MTX increased WWOX expression, accompanied by caspase activation and apoptosis, in MTX-sensitive SCC cell lines and tumor biopsies. Suppression by a dominant-negative or small interfering RNA targeting WWOX blocked MTX-mediated cell death in sensitive SCC-15 cells that highly expressed WWOX. In stark contrast, SCC-9 cells expressed minimum amount of WWOX protein and resisted MTX-induced apoptosis. Transiently overexpressed WWOX sensitized SCC-9 cells to apoptosis by MTX. MTX significantly downregulated autophagy-related Beclin-1, Atg12–Atg5 and LC3-II protein expression and autophagosome formation in the sensitive SCC-15, whereas autophagy remained robust in the resistant SCC-9. Mechanistically, WWOX physically interacted with mammalian target of rapamycin (mTOR), which potentiated MTX-increased phosphorylation of mTOR and its downstream substrate p70 S6 kinase, along with dramatic downregulation of the aforementioned proteins in autophagy, in SCC-15. When WWOX was knocked down in SCC-15, MTX-induced mTOR signaling and autophagy inhibition were blocked. Thus, WWOX renders SCC cells susceptible to MTX-induced apoptosis by dampening autophagy, and the failure in inducing WWOX expression leads to chemotherapeutic drug resistance.