Background: Lung cancer has long been the most dangerous malignant tumor among males in both well developed and poorly developed countries. Radiotherapy plays a critical role in the curative management of inoperable non-small cell lung cancer (NSCLC) and is also used as a post-surgical treatment in lung cancer patients. Radioresistance is an important factor that limits the efficacy of radiotherapy for NSCLC patients. Increasing evidence suggests that microRNAs (miRNAs) possess diverse cellular regulatory roles in radiation responses. Methods: In this study, we used miRNA microarray technology to identify serum miRNAs that were differentially expressed before and after radiotherapy in lung cancer patients. We further examined the biological function of miR-208a on cell viability, apoptotic death and cell cycle distribution in human lung cancer cells and explored the probable mechanism.

Radioresistance has been an important factor in restricting efficacy of radiotherapy for non-small cell lung cancer (NSCLC) patients and new approaches to inhibit cancer growth and sensitize irradiation were warranted. Despite the important role of ubiquitin/proteasome system (UPS) during cancer progression and treatment, the expression and biological role of ubiquitin (Ub) in human NSCLC has not been characterized. In this study, we found that ubiquitin was significantly overexpressed in 75 NSCLC tissues, compared to their respective benign tissues by immunohistochemistry (P < 0.0001). Knock-down of ubiquitin by mixed shRNAs targeting its coding genes ubiquitin B (UBB) and ubiquitin C (UBC) suppressed the growth and increased the radiosensitivity in NSCLC H1299 cells. Apoptosis and γ H2AX foci induced by X-ray irradiation were enhanced by knock-down of ubiquitin. Western blot and immunostaining showed that knock-down of ubiquitin decreased the expression and translocation of NF-κB to the nucleus by reduced phospho-IκBα after irradiation. Suppression of ubiquitin decreased the proliferation and radioresistance of H1299 transplanted xenografts in nude mice by promoting apoptosis. Taken together, our results demonstrate the critical role of ubiquitin in NSCLC proliferation and radiosensitivity. Targeting ubiquitin may serve as a potentially important and novel approach for NSCLC prevention and therapy.

BackgroundPrevious studies indicated that oral squamous cell carcinomas (OSCC) might be related to human papilloma virus (HPV) infection. However, up to now, there still lacks a large sample study to analyze the relationship between OSCC in a Chinese population and oral HPV infection. In the present study, we used a meta-analysis to evaluate the relationship of OSCC with HPV infection in a Chinese population.MethodsThe reports on HPV and OSCC in a Chinese population published between January, 1994, and September, 2011 were retrieved via CNKI/WANFANG/OVID/MEDLINE databases. According to the inclusion criteria, we selected 18 eligible case-control studies. After testing the heterogeneity of the studies by the Cochran Q test, the meta-analyses for HPV and HPV16 were performed using the fixed effects model.ResultsThe overall positive rates of HPV and HPV16 in OSCC were 58.0% (354/610; 95% confidence interval [CI], 54.1–61.9) and 47.47% (169/356; 95% CI: 42.3–52.7), respectively; which were significantly higher than those in normal controls 10.44% (26/249; 95% CI: 7.2–14.7) and 7.1% (13/182; 95% CI: 4.2–11.8). Quantitative meta-analysis revealed that, compared with normal controls, the combined odds ratios of OSCC with HPV or HPV16 infection were 12.7 (95% CI: 8.0–20.0) and 9.0 (95% CI: 5.1–15.6), respectively. Both Begg's test and funnel plots revealed that no publication bias was found in this present study (P>0.05).ConclusionsHigh incidences of HPV infection (mainly involving HPV16) were found in the samples of Chinese OSCC. For the Chinese population, HPV infection elevates the risk of OSCC tumorigenesis. Prophylactic HPV-vaccination may reduce the burden of HPV-related OSCC in China.

BackgroundThe p53 tumour suppressor protein is a transcription factor that prevents oncogenic progression by activating the expression of apoptosis and cell-cycle arrest genes in stressed cells. The stability of p53 is tightly regulated by ubiquitin-dependent degradation, driven mainly by its negative regulators ubiquitin ligase MDM2.Principal FindingsIn this study, we have identified OTUD5 as a DUB that interacts with and deubiquitinates p53. OTUD5 forms a direct complex with p53 and controls level of ubiquitination. The function of OTUD5 is required to allow the rapid activation of p53-dependent transcription and a p53-dependent apoptosis in response to DNA damage stress.ConclusionsAs a novel deubiquitinating enzyme for p53, OTUD5 is required for the stabilization and the activation of a p53 response.

Esophageal squamous cell carcinoma (ESCC) is one of the deadliest malignancies worldwide. Ying Yang 1 (YY1), a ubiquitously expressed GLI-Kr€ uppel zinc finger transcription factor, plays a regulatory role in a variety of fundamental biological processes, such as embryonic development, growth, apoptosis, differentiation and oncogenic transformation. The purpose of this study was to investigate the expression of YY1 in normal and cancerous esophageal tissues and its function in ESCC development. We found that the expression of YY1 mRNA was significantly increased in the tumor tissues, compared with the para-tissues or normal esophageal tissues. The increased expression of YY1 in tumor samples was further confirmed by immunohistochemistry. Furthermore, the overexpression of YY1 conferred radioresistance to the ESCC TE-1 cells and resulted in markedly reduced cell proliferation. Accordingly, the small interfering RNA-mediated silencing of YY1 expression in TE-1 cells resulted in increased proliferation by enhancing the binding of P21 to Cyclin D1 and CDK4, a protein complex known to mediate cell cycle progression. Moreover, besides P21, heme oxygenase-1 (HO-1) was identified as a YY1 downstream effector, as YY1 stimulated HO-1 expression in esophageal cancer cells. YY1 mediated biological function through transcription of HO-1. Forced expression of HO-1 could moderately suppress proliferation of TE-1 cells. The expression of YY1 significantly correlated with that of HO-1 in ESCC tissues. Taken together, we demonstrated overexpression of YY1 in esophageal carcinoma and identified HO-1 as its target. (Cancer Sci 2013; 104: 1544-1551 E sophageal squamous cell carcinoma (ESCC) remains the sixth most common cause of cancer-related death.(1) Despite intensive multimodality therapies, including surgery, radiotherapy and chemotherapy, the prognosis of this disease remains poor. Patients with esophageal carcinomas have a low 5-year survival rate because of late diagnosis and the rapid spread of cancer cells.(2) The pathology of ESCC remains complex and largely unknown. Understanding the biological mechanisms involved in esophageal tumor development has emerged as a significant issue in ESCC research. Accumulating evidence indicates that transcription factors have emerged as important players in human cancer development and progression. The aberrant activation of these transcription factors leads to the deregulated expression of multiple gene sets. The activation or inactivation of transcription factors promotes cancer development, cell survival and proliferation and induces tumor angiogenesis. (3,4) Ying Yang 1 (YY1), a ubiquitously expressed GLI-Kr€ uppel zinc finger transcription factor, plays a regulatory role in a variety of fundamental biological processes, such as embryonic development, growth, apoptosis, differentiation and oncogenic transformation.(5) YY1 is capable of influencing gene expression via its ability to directly or indirectly activate or suppress gene transcription.(6) Moreover, YY1 has also been shown t...