Deficiency for Lcn8 causes epididymal sperm maturation defects in mice

Lipocalin family members, LCN8 and LCN9, are specifically expressed in the initial segment of mouse caput epididymis. However, the biological functions of the molecules in vivo are yet to be clarified. In this study, CRISPR/Cas9 technology was used to generate Lcn8 and Lcn9 knockout mice, respectively. Lcn8-/- and Lcn9-/- male mice showed normal spermatogenesis and fertility. In the cauda epididymis of Lcn8-/- male mice, morphologically abnormal sperm was increased significantly, the proportion of progressive motility sperm was decreased, the proportion of immobilized sperm was elevated, and the sperm spontaneous acrosome reaction (AR) frequency was increased. Conversely, the knockout of Lcn9 did not have any effect on the ratio of morphologically abnormal sperm, sperm motility, and sperm spontaneous AR frequencies. These results demonstrated the role of LCN8 in maintaining the sperm quality in the epididymis, and suggested that the deficiency of LCN8 leads to epididymal sperm maturation defects.

What deubiquitinating enzymes, oncogenes, and tumor suppressors actually do: Are current assumptions supported by patient outcomes?

Context can determine whether a given gene acts as an oncogene or a tumor suppressor. Deubiquitinating enzymes (DUBs) regulate the stability of many components of the pathways dictating cell fate so it would be expected that alterations in the levels or activity of these enzymes may have oncogenic or tumor suppressive consequences. In the current review we survey publications reporting that genes encoding DUBs are oncogenes or tumor suppressors. For many DUBs both claims have been made. For such "double agents," the effects of gain or loss of function will depend on the overall status of a complex of molecular signaling networks subject to extensive crosstalk. As the TGF-β paradox makes clear context is critical in cell fate decisions, and the disconnect between experimental findings and patient survival outcomes can in part be attributed to disparities between culture conditions and the microenvironment in vivo. Convincing claims for oncogene or tumor suppressor roles require the documentation of gene alterations in patient samples; survival curves are alone inadequate.

Deubiquitinase USP18 promotes the progression of pancreatic cancer via enhancing the Notch1-c-Myc axis

The dysregulation of deubiquitinating enzymes (DUBs), which regulate the stability of most cellular proteins, has been implicated in many human diseases, including cancers. Thus, DUBs can be considered potential therapeutic targets for many cancers. However, the role of deubiquitinase ubiquitin-specific protease 18 (USP18) in pancreatic cancer remains unknown. Here, we found that the deubiquitinase ubiquitin-specific protease 18 (USP18) is significantly upregulated in pancreatic cancer and is correlated with a shorter median overall and relapse-free survival. A functional assay demonstrated that overexpression of USP18 resulted in increased proliferation of pancreatic cancer cells. Conversely, these phenomena were reversed after USP18 was silenced in pancreatic cancer cells. Further investigation revealed that USP18 promoted cell progression by increasing c-Myc expression, which has been reported to control pancreatic cancer progression, and our data demonstrated that c-Myc is key for USP18-mediated pancreatic cancer cell progression in vitro and in vivo. Moreover, we found that USP18 promoted pancreatic cancer progression via upregulation of Notch-1-dependent c-Myc. Mechanistically, USP18 interacts with and removes K48-linked ubiquitin chains from Notch1, thereby stabilizing Notch1 and promoting the Notch1-c-Myc pathway. Our work identifies and validates USP18 as a pancreatic cancer oncogene and provides a potential druggable target for this intractable disease.