We sequenced whole exomes of ten clear cell renal cell carcinomas (ccRCCs) and performed a screen of ∼1,100 genes in 88 additional ccRCCs, from which we discovered 12 previously unidentified genes mutated at elevated frequencies in ccRCC. Notably, we detected frequent mutations in the ubiquitin-mediated proteolysis pathway (UMPP), and alterations in the UMPP were significantly associated with overexpression of HIF1α and HIF2α in the tumors (P = 0.01 and 0.04, respectively). Our findings highlight the potential contribution of UMPP to ccRCC tumorigenesis through the activation of the hypoxia regulatory network.

Azoospermia is one of the major reproductive disorders which cause male infertility in humans; however, the etiology of this disease is largely unknown. In the present study, six missense mutations of WT1 gene were detected in 529 human patients with non-obstructive azoospermia (NOA), indicating a strong association between WT1 mutation and NOA. The Wilms tumor gene, Wt1, is specifically expressed in Sertoli cells (SCs) which support spermatogenesis. To examine the functions of this gene in spermatogenesis, Wt1 was deleted in adult testis using Wt1flox and Cre-ERTM mice strains. We found that inactivation of Wt1 resulted in massive germ cell death and only SCs were present in most of the seminiferous tubules which was very similar to NOA in humans. In investigating the potential mechanism for this, histological studies revealed that the blood–testis barrier (BTB) was disrupted in Wt1 deficient testes. In vitro studies demonstrated that Wt1 was essential for cell polarity maintenance in SCs. Further studies found that the expression of cell polarity associated genes (Par6b and E-cadherin) and Wnt signaling genes (Wnt4, Wnt11) were downregulated in Wt1 deficient SCs, and that the expression of Par6b and E-cadherin was regulated by Wnt4. Our findings suggest that Wt1 is important in spermatogenesis by regulating the polarity of SCs via Wnt signaling pathway and that WT1 mutation is one of the genetic causes of NOA in humans.

BackgroundTo understand the involvement of structural maintenance of chromosome 4 (SMC4) in the development and progression of hepatocellular carcinoma (HCC).MethodsReal-time quantitative PCR and Western Blotting were applied to measure the expression of SMC4 in HCC samples and cell lines. The tumor-promoting effect of SMC4 was determined by WST-1, soft agar colony formation, cell motility and invasion assays. The SMC4 target signal pathway was identified by luciferase reporter and real-time quantitative PCR assays.ResultsThe upregulation of SMC4 was frequently detected in HCC samples and cell lines. Functional assays demonstrated that SMC4 could effectively promote tumor cell growth rate, colony formation in soft agar, wound-healing and invasion. Further studies showed that increased miR-219 levels caused a significant decrease in the SMC4 expression, and SMC4 inhibitor downregulated JAK2/Stat3 expression at both the mRNA and protein levels.ConclusionsOur findings provide new insight into SMC4 function and the mechanisms of growth and invasion of HCC.

Structural maintenance of chromosome 4 (SMC4) is associated with tumorigenesis. The present study aimed at detecting SMC4 expression in primary liver cancer and its association with clinicopathological patient data. A total of 72 primary liver cancer tissues and 6 liver cell lines were assessed for expression of SMC4 mRNA and protein with qRT-PCR, western blotting and immunohistochemistry, respectively. SMC4 siRNAs were constructed to knockdown SMC4 expression, and phenotypic changes of hepatocellular carcinoma (HCC) cells were analyzed using flow cytometry and cell viability assays. The data showed that SMC4 mRNA and protein were highly expressed in HCC tissues compared to the normal tissues. Immunohistochemical analysis revealed that 52 of 72 (72.2%) paraffin-embedded primary liver cancer tissues displayed strong cytoplasmic staining of SMC4 protein, whereas only 6 (8.3%) normal liver tissues showed immunostaining of SMC4. Statistical analysis showed that SMC4 expression was significantly associated with tumor size, de-differentiation, advanced stages and vascular invasion of the primary liver cancers. Moreover, knockdown of SMC4 expression reduced HCC cell proliferation. These data demonstrated that expression of SMC4 protein may be useful for the early detection and prediction of primary liver cancer progression.