UBE2M-mediated p27(Kip1) degradation in gemcitabine cytotoxicity

Non-coding RNA transcripts, incredible modulators of cisplatin chemo-resistance in bladder cancer through operating a broad spectrum of cellular processes and signaling mechanism

Bladder cancer (BC) is a highly frequent neoplasm in correlation with significant rate of morbidity, mortality, and cost. The onset of BC is predominantly triggered by environmental and/or occupational exposures to carcinogens, such as tobacco. There are two distinct pathways by which BC can be developed, including non-muscle-invasive papillary tumors (NMIBC) and non-papillary (or solid) muscle-invasive tumors (MIBC). The Cancer Genome Atlas project has further recognized key genetic drivers of MIBC along with its subtypes with particular properties and therapeutic responses; nonetheless, NMIBC is the predominant BC presentation among the suffering individuals. Radical cystoprostatectomy, radiotherapy, and chemotherapy have been verified to be the common therapeutic interventions in metastatic tumors, among which chemotherapeutics are more conventionally utilized. Although multiple chemo drugs have been broadly administered for BC treatment, cisplatin is reportedly the most effective chemo drug against the corresponding malignancy. Notwithstanding, tumor recurrence is usually occurred following the consumption of cisplatin regimens, particularly due to the progression of chemo-resistant trait. In this framework, non-coding RNAs (ncRNAs), as abundant RNA transcripts arise from the human genome, are introduced to serve as crucial contributors to tumor expansion and cisplatin chemo-resistance in bladder neoplasm. In the current review, we first investigated the best-known ncRNAs, i.e. microRNAs (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs), correlated with cisplatin chemo-resistance in BC cells and tissues. We noticed that these ncRNAs could mediate the BC-related cisplatin-resistant phenotype through diverse cellular processes and signaling mechanisms, reviewed here. Eventually, diagnostic and prognostic potential of ncRNAs, as well as their therapeutic capabilities were highlighted in regard to BC management.

UBE2M Drives Hepatocellular Cancer Progression as a p53 Negative Regulator by Binding to MDM2 and Ribosomal Protein L11

Simple Summary

Herein, the oncogenic role of UBE2M as an E2 NEDD8-conjugating enzyme was explored in hepatocellular carcinoma (HCC) cells, since neddylation plays a critical role in tumorigenesis. To address this issue, human tissue array and TCGA analysis were conducted in HCCs to find overexpression of UBE2M in HCCs. In addition, a differential profile was confirmed in UBE2M-depleted HepG2 cells. Furthermore, UBE2M depletion activated p53 expression and stability, while the ectopic expression of UBE2M disturbed p53 activation and enhanced degradation of exogenous p53 mediated by MDM2 in HepG2 cells via binding to MDM2 and ribosomal protein L11 by immunoprecipitation and immunofluorescence. These findings provide evidence that UBE2M is critically involved in liver cancer progression as a p53 negative regulator by binding to MDM2 and ribosomal protein L11.

Abstract

Though UBE2M, an E2 NEDD8-conjugating enzyme, is overexpressed in HepG2, Hep3B, Huh7 and PLC/PRF5 HCCs with poor prognosis by human tissue array and TCGA analysis, its underlying oncogenic mechanism remains unclear. Herein, UBE2M depletion suppressed viability and proliferation and induced cell cycle arrest and apoptosis via cleavages of PARP and caspase 3 and upregulation of p53, Bax and PUMA in HepG2, Huh7 and Hep3B cells. Furthermore, UBE2M depletion activated p53 expression and stability, while the ectopic expression of UBE2M disturbed p53 activation and enhanced degradation of exogenous p53 mediated by MDM2 in HepG2 cells. Interestingly, UBE2M binds to MDM2 or ribosomal protein L11, but not p53 in HepG2 cells, despite crosstalk between p53 and UBE2M. Consistently, the colocalization between UBE2M and MDM2 was observed by immunofluorescence. Notably, L11 was required in p53 activation by UBE2M depletion. Furthermore, UBE2M depletion retarded the growth of HepG2 cells in athymic nude mice along with elevated p53. Overall, these findings suggest that UBE2M promotes cancer progression as a p53 negative regulator by binding to MDM2 and ribosomal protein L11 in HCCs.

Gemcitabine-induced Gli-dependent activation of hedgehog pathway resists to the treatment of urothelial carcinoma cells

Patients with urothelial carcinoma (UC) experience gemcitabine resistance is a critical issue. The role of hedgehog pathway in the problem was explored. The expressions of phospho-AKT^ser473, phospho-GSK3β^ser9 and Gli2 were up-regulated in gemcitabine-resistant NTUB1 (NGR) cells. Without hedgehog ligands, Gli proteins can be phosphorylated by GSK3β kinase to inhibit their downstream regulations. Furthermore, the GSK3β kinase can be phosphorylated by AKT at its Ser9 residue to become an inactive kinase. Therefore, overexpression of AKT1, Flag-GSK^S9D (constitutively inactive form) or active Gli2 (GLI2ΔN) in NTUB1 cells could activate Gli2 pathway to enhance migration/invasion ability and increase gemcitabine resistance, respectively. Conversely, overexpression of Flag-GSK^S9A (constitutively active form) or knockdown of Gli2 could suppress Gli2 pathway, and then reduce gemcitabine resistance in NGR cells. Therefore, we suggest gemcitabine-activated AKT/GSK3β pathway can elicit Gli2 activity, which leads to enhanced migration/invasion ability and resistance to gemcitabine therapy in UC patients. The non-canonical hedgehog pathway should be evaluated in the therapy to benefit UC patients.

Identification of MTHFD2 as a novel prognosis biomarker in esophageal carcinoma patients based on transcriptomic data and methylation profiling

DNA methylation is an important epigenetic regulatory mechanism in esophageal carcinoma (EC) and is associated with genomic instability and carcinogenesis. In the present study, we aimed to identify tumor biomarkers for predicting prognosis of EC patients.We downloaded mRNA expression profiles and DNA methylation profiles associated with EC from the Gene Expression Omnibus database. Differentially expressed and differentially methylated genes between tumor tissues and adjacent normal tissue samples were identified. Functional enrichment analyses were performed, followed by the construction of protein-protein interaction networks. Data were validated based on methylation profiles from The Cancer Genome Atlas. Candidate genes were further verified according to survival analysis and Cox regression analysis.We uncovered multiple genes with differential expression or methylation in tumor samples compared with normal samples. After taking the intersection of 3 differential gene sets, we obtained a total of 232 overlapping genes. Functional enrichment analysis revealed that these genes are related to pathways such as "glutathione metabolism," "p53 signaling pathway," and "focal adhesion." Furthermore, 8 hub genes with inversed expression and methylation correlation were identified as candidate genes. The abnormal expression levels of MSN, PELI1, and MTHFD2 were correlated with overall survival times in EC patients (P < .05). Only MTHFD2 was significantly associated with a pathologic stage according to univariate analysis (P = .037) and multivariate analysis (P = .043).Our study identified several novel EC biomarkers with prognostic value by integrated analysis of transcriptomic data and methylation profiles. MTHFD2 could serve as an independent biomarker for predicting prognosis and pathological stages of EC.

UBE2M promotes cell proliferation via the β-catenin/cyclin D1 signaling in hepatocellular carcinoma

Upregulated ubiquitin-conjugating enzyme E2M (UBE2M) is associated with poor prognosis in malignancies; However, the phenotype and mechanism of action of UBE2M in hepatocellular carcinoma (HCC) remain elusive. Here, we report that UBE2M is overexpressed and correlated with poor prognosis in HCC patients. The UBE2M level is an independent prognostic factor for HCC patients. UBE2M knockdown inhibits HCC cell proliferation, migration, and invasion, whereas its overexpression has an opposite effect. Mechanistically, upregulated UBE2M exerts oncogenic effects by translocation of accumulated β-catenin from the cytoplasm to the nucleus, thus activating downstream β-catenin/cyclin D1 signaling. In summary, our study demonstrates a notable role of UBE2M in promoting the growth of HCC, providing a novel strategy for HCC prevention and treatment.

UBE2M Is a Stress-Inducible Dual E2 for Neddylation and Ubiquitylation that Promotes Targeted Degradation of UBE2F

UBE2M and UBE2F are two family members of neddylation E2 conjugating enzyme that, together with E3s, activate CRLs (Cullin-RING Ligases) by catalyzing cullin neddylation. However, whether and how two E2s cross-talk with each other are largely unknown. Here, we report that UBE2M is a stress-inducible gene subjected to cis-transactivation by HIF-1 and AP1, and MLN4924, a small molecule inhibitor of E1 NEDD8-activating enzyme (NAE), upregulates UBE2M via blocking degradation of HIF-1α and c-JUN. UBE2M is a dual E2 for targeted ubiquitylation and degradation of UBE2F, acting as a neddylation E2 to activate CUL3-Keap1 E3 under physiological conditions but as a ubiquitylation E2 for Parkin-DJ-1 E3 under stressed conditions. UBE2M-induced UBE2F degradation leads to CRL5 inactivation and subsequent NOXA accumulation to suppress the growth of lung cancer cells. Collectively, our study establishes a negative regulatory axis between two neddylation E2s with UBE2M ubiquitylating UBE2F, and two CRLs with CRL3 inactivating CRL5.

MiR-193b Mediates CEBPD-Induced Cisplatin Sensitization Through Targeting ETS1 and Cyclin D1 in Human Urothelial Carcinoma Cells

Transcription factor CCAAT/enhancer-binding protein delta (CEBPD) plays multiple roles in tumor progression. Studies have demonstrated that cisplatin (CDDP) induced CEBPD expression and had led to chemotherapeutic drug resistance. However, the underlying molecular mechanisms of CDDP-regulated CEBPD expression and its relevant roles in CDDP responses remain elusive. MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate gene expression in a sequence-specific manner. Abnormal miRNAs expression is associated with tumor progression. In current study, a large-scale PCR-based miRNA screening was performed to identify CEBPD-associated miRNAs in urothelial carcinoma cell line NTUB1. Eleven miRNAs were selected with more than twofold changes. MiR-193b-3p, a known tumor suppressor, down-regulated proto-oncogenes Cyclin D1, and ETS1 expression and led to cell cycle arrest, cell invasion, and migration inhibition. The expression of miR-193b-3p was associated with the DNA binding ability of CEBPD in CDDP response. CEBPD knocking-down approach provided a strong evidence of the positive correlation between CEBPD and miR-193b-3p. CDDP-induced CEBPD trans-activated miR-193b-3p expression and it directly targeted the 3'-UTR of Cyclin D1 and ETS1 mRNA, and silenced the protein expression. In addition, miR-193b-3p also inhibited cell migration activity, arrested cell at G1 phase, and sensitized NTUB1 to CDDP treatment. In conclusion, this study indicates that CEBPD exhibits an anti-tumorigenic function through transcriptionally activating miR-193b-3p expression upon CDDP treatment. This study provides a new direction for managing human urothelial carcinoma. J. Cell. Biochem. 118: 1563-1573, 2017. © 2016 Wiley Periodicals, Inc.

Histone deacetylase inhibitor trichostatin A resensitizes gemcitabine resistant urothelial carcinoma cells via suppression of TG-interacting factor

Gemcitabine and cisplatin (GC) has been widely used for advanced and metastatic urothelial carcinoma (UC). However, resistance to this remedy has been noticed. We have demonstrated that increase of TG-interacting factor (TGIF) in specimens is associated with worse prognosis of upper tract UC (UTUC) patients. The roles of TGIF in the gemcitabine resistance of UC were explored. Specimens of 23 locally advanced/advanced stage UTUC patients who received GC systemic chemotherapy after radical nephroureterectomy were collected to evaluate the alterations of TGIF in the resistance to the remedy by using immunohistochemistry. In vitro characterizations of mechanisms mediating TGIF in gemcitabine resistance were conducted by analyzing NTUB1 cells and their gemcitabine-resistant subline, NGR cells. Our results show that increased TGIF is significantly associated with chemo-resistance, poor progression-free survival, and higher cancer-related deaths of UTUC patients. Higher increases of TGIF, p-AKT(Ser473) and invasive ability were demonstrated in NGR cells. Overexpression of TGIF in NTUB1 cells upregulated p-AKT(Ser473) activation, enhanced migration ability, and attenuated cellular sensitivity to gemcitabine. Knockdown of TGIF in NGR cells downregulated p-AKT(Ser473) activation, declined migration ability, and enhanced cellular sensitivity to gemcitabine. In addition, histone deacetylases inhibitor trichostatin A (TSA) inhibited TGIF, p-AKT(Ser473) expression and migration ability. Synergistic effects of gemcitabine and TSA on NGR cells were also demonstrated. Collectively, TGIF contributes to the gemcitabine resistance of UC via AKT activation. Combined treatment with gemcitabine and TSA might be a promising therapeutic remedy to improve the gemcitabine resistance of UC.

Increased level of MSU crystal-bound protein apolipoprotein A-I in acute gouty arthritis

BACKGROUND

Gout is a common form of inflammatory arthritis that is triggered by the crystallization of monosodium urate (MSU). We investigated the potential proteins that relate to the pathogenesis or the spontaneous resolution of acute gouty arthritis.

METHOD

We screened for differentially expressed proteins in the plasma of patients with acute gouty arthritis using two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS) identification. We confirmed these findings in a population study of 209 subjects, and further determined the protein profile of the synovial fluid (SF) from 24 gouty patients during acute attack by liquid chromatography coupled with tandem MS (LC/MS/MS).

RESULTS

The highly expressed apolipoprotein A-I (apoA-I) was identified in the plasma of acute gouty patients compared with healthy controls. Moreover, we detected high levels of SF apoA-I in 83.3% of acute gouty patients during attack. From the population study, apoA-I was increasingly associated with normouricaemia, hyperuricaemia, and acute gouty arthritis (ptrend < 0.001), and plasma uric acid (UA) and apoA-I were positively correlated (p = 0.0156). We used a human liver cell model and found that UA enhanced the hepatic apoA-I mRNA expression level (ptrend < 0.01) and apoA-I secretion level (ptrend = 0.002) in a dose-dependent manner. An elevated MSU concentration caused the endogenous apoA-I to deplete gradually.

CONCLUSIONS

Based on the role of apoA-I in anti-inflammation, our observational data in acute gout support the hypothesis that apoA-I expression can be induced under the condition of a high concentration of UA and its elevated level may be implicated in the spontaneous resolution of acute gouty arthritis.

Involvement of p38 mitogen-activated protein kinase in acquired gemcitabine-resistant human urothelial carcinoma sublines

Resistance to chemotherapeutic drugs is one of the major challenges in the treatment of cancer. A better understanding of how resistance arises and what molecular alterations correlate with resistance is the key to developing novel effective therapeutic strategies. To investigate the underlying mechanisms of gemcitabine (Gem) resistance and provide possible therapeutic options, three Gem-resistant urothelial carcinoma sublines were established (NG0.6, NG0.8, and NG1.0). These cells were cross-resistant to arabinofuranosyl cytidine and cisplatin, but sensitive to 5-fluorouracil. The resistant cells expressed lower values of [hENT1 × dCK/RRM1 × RRM2] mRNA ratio. Two adenosine triphosphate-binding cassette proteins ABCD1 as well as multidrug resistance protein 1 were elevated. Moreover, cyclin D1, cyclin-dependent kinases 2 and 4 were upregulated, whereas extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase (MAPK) activity were repressed significantly. Administration of p38 MAPK inhibitor significantly reduced the Gem sensitivity in NTUB1 cells, whereas that of an extracellular signal-regulated kinase MAPK inhibitor did not. Furthermore, the Gem-resistant sublines also exhibited higher migration ability. Forced expression of p38 MAPK impaired the cell migration activity and augmented Gem sensitivity in NG1.0 cells. Taken together, these results demonstrate that complex mechanisms were merged in acquiring Gem resistance and provide information that can be important for developing therapeutic targets for treating Gem-resistant tumors.

Celecoxib-induced cytotoxic effect is potentiated by inhibition of autophagy in human urothelial carcinoma cells

Celecoxib, a cyclooxygenase-2 (COX-2) inhibitor, can elicit anti-tumor effects in various malignancies. Here, we sought to clarify the role of autophagy in celecoxib-induced cytotoxicity in human urothelial carcinoma (UC) cells. The results shows celecoxib induced cellular stress response such as endoplasmic reticulum (ER) stress, phosopho-SAPK/JNK, and phosopho-c-Jun as well as autophagosome formation in UC cells. Inhibition of autophagy by 3-methyladenine (3-MA), bafilomycin A1 or ATG7 knockdown potentiated celecoxib-induced apoptosis. Up-regulation of autophagy by rapamycin or GFP-LC3B-transfection alleviated celecoxib-induced cytotoxicity in UC cells. Taken together, the inhibition of autophagy enhances therapeutic efficacy of celecoxib in UC cells, suggesting a novel therapeutic strategy against UC.