The NONO (non-POU domain-containing octamer-binding protein) protein, also known as 54 kD nuclear RNA-and DNA-binding protein (p54nrb), belongs to the multifunctional DBHS (Drosophila behaviour/human splicing) family of proteins which can bind DNA, RNA and protein. 1 NONO has a nuclear localization signal (NLS) at its C-terminal, so it is located in the nucleus of most mammalian cells and is primarily distributed in the subnuclear domain named paraspeckles. 2 Emerging evidence strongly indicates new roles for NONO in tumorigenesis, including but not limited to regulating proliferation, apoptosis, cell migration and DNA damage repair. Here, we provide a comprehensive review of the NONO and its functions in tumorigenesis. AbstractThe non-POU domain-containing octamer-binding protein NONO/p54 nrb , which belongs to the Drosophila behaviour/human splicing (DBHS) family, is a multifunctional nuclear protein rarely functioning alone. Emerging solid evidences showed that NONO engages in almost every step of gene regulation, including but not limited to mRNA splicing, DNA unwinding, transcriptional regulation, nuclear retention of defective RNA and DNA repair. NONO is involved in many biological processes including cell proliferation, apoptosis, migration and DNA damage repair. Dysregulation of NONO has been found in many types of cancer. In this review, we summarize the current and fast-growing knowledge about the regulation of NONO, its biological function and implications in tumorigenesis and cancer progression. Overall, significant findings about the roles of NONO have been made, which might make NONO to be a new biomarker or/and a possible therapeutic target for cancers. K E Y W O R D S DBHS, NONO, splicing, tumorigenesis | 4369 FENG Et al.

The deubiquitinase DUB3 is frequently overexpressed in non-small cell lung cancer (NSCLC) and contributes to its malignant phenotype. However, the underlying molecular mechanism of DUB3 in NSCLC is largely unknown. In this study, we report that DUB3 regulates cell cycle progression by deubiquitinating cyclin A that links to proliferation of NSCLC cells. We found that knockdown of DUB3 decreases cyclin A levels, whereas overexpression of DUB3 strongly increases cyclin A levels. Mechanistically, DUB3 interacts with cyclin A, which removes the polyubiquitin chains conjugated onto cyclin A and stabilizes the cyclin A protein. Furthermore, we demonstrate that DUB3 regulates cell cycle progression by stabilizing cyclin A, because ablation of DUB3 arrests cell cycle from G0/G1 to S phase and the resulting effect can be rescued by introducing cyclin A into NSCLC cells. Functionally, we found that the effect of DUB3 on cyclin A mediates proliferation of NSCLC cells. Moreover, a significant correlation between DUB3 abundance and cyclin A expression levels were also found in NSCLC samples. Taken together, these results reveal that DUB3 functions as a novel cyclin A regulator through maintaining cyclin A stability, and that the DUB3-cyclin A signaling axis plays a critical role in cell cycle progression for proliferation of NSCLC.

Hepatocellular carcinoma (HCC) is a type of cancer that has high rates of recurrence and mortality. One of the most important factors that lead to treatment failure of HCC is the acquisition of multidrug resistance (MDR). Development of specific ligands for multidrug-resistant HCC will provide useful molecular tools for precise diagnosis and targeted theranostics. Herein, a multidrug-resistant HCC cell (HepG2/MDR)-specific aptamer was developed through Cell-SELEX (systematic evolution of ligands by exponential enrichment) technology. With dissociation constants lying in the nanomolar range, the molecularly designed PS-ZL-7c aptamer showed great selectivity to drug-resistant cancer cells. The in vivo imaging results illustrated that the PS-ZL-7c specifically accumulated in the drug-resistant tumors but not in drug-sensitive tumors and normal tissues, indicating that the PS-ZL-7c aptamer possessed excellent potential as a targeting ligand for precise diagnosis and target theranostics of multidrug-resistant HCC.

Chemically synthetic receptors that establish cells a new sense-and-respond capability to interact with outer worlds are highly desired, but rarely reported. In this work, we develop a membrane-anchored synthetic receptor (Ts-pHLIP-Pr) using DNA and peptide as the building block to equip cells with artificial signaling pathways. Upon sensing external pH stimuli, the Pr module can be translocated across the cell membrane via the conformation switch of pHLIP, enabling membrane-proximal recruitment of specific proteins to trigger downstream signaling cascades. Our experimental results demonstrate the capability of Ts-pHLIP-Pr for regulating PKCε-related signaling events upon responding to external pH reduction. With a modular feature, this receptor can be extended to elicit T cell activation through low-pH environment-induced directional movement of cytoplasmic ZAP70. Our work is expected to offer a new paradigm for intelligent synthetic biology and customized cell engineering.

Ubiquitin‐specific protease 11 (USP11) has been implicated in the regulation of DNA repair, apoptosis, signal transduction and cell cycle. It belongs to a USP subfamily of deubiquitinases. Although previous research has shown that USP11 overexpression is frequently found in melanoma and is correlated with a poor prognosis, the potential molecular mechanism of USP11 in melanoma remains indefinitive. Here, we report that USP11 and NONO colocalize and interact with each other in the nucleus of melanoma cells. As a result, the knockdown of USP11 decreases NONO levels. Whereas, overexpression of USP11 increases NONO levels in a dose‐dependent manner. Furthermore, we reveal that USP11 protects NONO protein from proteasome‐mediated degradation by removing poly‐ubiquitin chains conjugated onto NONO. Functionally, USP11 mediated melanoma cell proliferation via the regulation of NONO levels because ablation of USP11 inhibits the proliferation which could be rescued by ectopic expression of NONO protein. Moreover, a significant positive correlation between USP11 and NONO concentrations was found in clinical melanoma samples. Collectively, these results demonstrate that USP11 is a new deubiquitinase of NONO and that the signalling axis of USP11‐NONO is significantly involved in melanoma proliferation.