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Nanjing, China

Li X.J.,Nanjing Medical University | Ren R.J.,Jiangsu Cancer Hospital | Tang J.H.,Nanjing Medical University
Cell Death and Disease | Year: 2014

MicroRNAs (miRs) are small noncoding RNAs that negatively regulate gene expression by binding to the three untranslated regions of their target mRNAs. Deregulations of miRs were shown to play pivotal roles in tumorigenesis and progression. Recent research efforts have been devoted to translating these basic discoveries into applications that could improve the therapeutic outcome of patients with cancer. MiR-34a is a highly conserved miR throughout many different species. In humans, there are three homologs (hsa-MiR34a, hsa-MiR-34b and hsa-MiR-34c). Early studies have shown that miR-34a acts as a tumor-Suppressor gene by targeting many oncogenes related to proliferation, apoptosis and invasion. In this review, we provide a complex overview of miR-34a, including regulating its expression, its known functions in cancer and future challenges as a potential therapeutic target in human cancers. © 2014 Macmillan Publishers Limited All rights reserved 2041-4889/14.

Sun X.-X.,Oregon Health And Science University | He X.,Oregon Health And Science University | Yin L.,Jiangsu Cancer Hospital | Komada M.,Tokyo Institute of Technology | And 2 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

c-Myc protein stability and activity are tightly regulated by the ubiquitin-proteasome system. Aberrant stabilization of c-Myc contributes to many human cancers. c-Myc is ubiquitinated by SCFFbw7(a SKP1-cullin-1-F-box complex that contains the F-box and WD repeat domain-containing 7, Fbw7, as the F-box protein) and several other ubiquitin ligases, whereas it is deubiquitinated and stabilized by ubiquitin-specific protease (USP) 28. The bulk of c-Myc degradation appears to occur in the nucleolus. However, whether c-Myc is regulated by deubiquitination in the nucleolus is not known. Here, we report that the nucleolar deubiquitinating enzyme USP36 is a novel c-Myc deubiquitinase. USP36 interacts with and deubiquitinates c-Myc in cells and in vitro, leading to the stabilization of c-Myc. This USP36 regulation of c-Myc occurs in the nucleolus. Interestingly, USP36 interacts with the nucleolar Fbw7γ but not the nucleoplasmic Fbw7α. However, it abolished c-Myc degradation mediated both by Fbw7γ and by Fbw7α. Consistently, knockdown of USP36 reduces the levels of c-Myc and suppresses cell proliferation. We further show that USP36 itself is a c-Myc target gene, suggesting that USP36 and c-Myc form a positive feedback regulatory loop. High expression levels of USP36 are found in a subset of human breast and lung cancers. Altogether, these results identified USP36 as a crucial and bono fide deubiquitinating enzyme controlling c-Myc's nucleolar degradation pathway. © 2015, National Academy of Sciences. All rights reserved.

Wang C.,Jiangsu Diabetes Research Center | Wang C.,Nanjing University | Bian Z.,Jiangsu Diabetes Research Center | Wei D.,Jiangsu Cancer Hospital | Zhang J.-G.,Harbin Medical University
Molecular and Cellular Biochemistry | Year: 2011

microRNAs (miRNAs) are short non-coding RNAs that regulate gene expression by targeting mRNAs, inhibiting the expression of the associated proteins. Although a role for aberrant miRNA expression in cancer has been postulated, the pathophysiologic role and relevance of aberrantly expressed miRNAs in tumor biology has not been established. We evaluated the expression pattern of miRNAs in human breast cancer cells by qPCR, finding out an up-regulated miRNA miR-29b and studying its biological effect by migration assay. We defined a target gene PTEN by bioinformatics approach and western blot. In breast cancer cell line MDA-MB-231 cell, which migrate faster than MCF-7, we observed that miR-29b was highly over-expressed. Inhibition of miR-29b in cultured cells increased the expression of the phosphatase and tensin homolog (PTEN) tumor suppressor, promoting apoptosis, decreasing migration, and decreasing invasion. In contrast, enhanced miR-29b expression by transfection with pre-miR-29b decreased the expression of PTEN and impaired apoptosis, increasing tumor cell migration and invasion. Moreover, PTEN was shown to be a direct target of miR-29b and was also shown to contribute to the miR-29b-mediated effects on cell invasion. Modulation of miR-29b altered the role of PTEN involved in cell migration and invasion. Aberrant expression of miR-29b, which modulates PTEN expression, can contribute to migration, invasion, and anti-apoptosis. © 2011 Springer Science+Business Media, LLC.

Gao W.,Nanjing Medical University | Lu X.,Changshu No.1 Peoples Hospital | Liu L.,Nanjing Medical University | Xu J.,Nanjing Medical University | And 2 more authors.
Cancer Biology and Therapy | Year: 2012

Purpose: To investigate the possible role of microRNAs in the resistance to platinum based chemotherapy in non-small cell lung cancer (NSCLC), explore their potential role and find potential biomarkers for prediction of the response to platinum. Results: 21 miRNAs were deregulated in A549/CDDP. Increased miR-21 expression significantly increased the resistance of A549 cell to platinum, whereas reduced miR-21 decreased the resistance of A549/CDDP cell. This finding was further validated in the tissue samples of 58 patients and it was found that miR-21 expression was significantly increased in platinum based chemotherapy-resistant patients (n = 58, p = 0.000). And increased miR-21 expression was associated with the shorter DFS (p = 0.008). Among these 58 patients, 32 had the corresponding plasma samples and similar tendencies were detected in 68.75% patients. Finally, transfection of A549/CDDP with anti-miR-21 increased the expression of PTEN and decreased Bcl-2. In contrast, pre-miR-21 decreased the expression of PTEN and increased Bcl-2 in A549. Patients and Methods: Microarray was employed to compare the expression of miRNAs between A549 and A549/ CDDP cells. The effect of a differently expressed miRNA (miR-21) was examined on the sensitivity of cells to platinum. MiR- 21 expression in NSCLC tumor tissues and matched plasma sample was also analyzed by Real-time PCR. Conclusion: Our data suggests that the expression level of miR-21 in tumor tissue and plasma might be used as a biomarker to predict adjuvant platinum based chemotherapy response and disease free survival in patients with NSCLC. Thus, it may serve as a novel therapeutic target to modulate platinum-based chemotherapy. © 2012 Landes Bioscience.

To investigate the effect of hyperthermic intraoperative intraperitoneal chemotherapy(HIIC) and postoperative nutritional support on the intestinal permeability and the cellular immunity function in patients with advanced gastric cancer. All the patients diagnosed as advanced gastric cancer in the Gastric Tumor Diagnosis and Treatment Center of Jiangsu Cancer Hospital were randomly divided into three groups using random digit table:(1)EN group treated with enteral nutrition during postoperative period; (2)HIIC+EN group treated with HIIC combined with postoperative enteral nutrition;(3)HIIC+PN group treated with HIIC combined with postoperative parenteral nutrition. Index of lactulose/mannitol(L/M) ratio was used to evaluate the permeability of intestinal mucosa. The percentage of CD4(+), CD8(+) and NK cell, the ratio of CD4/CD8 T cell in peripheral blood were tested by flow cytometry. The time points of these measurements were the day before surgery, postoperative days (POD) 3, 7, and 12. Compared with the day before surgery(POD-1), the ratio of L/M on POD+3 increased significantly in all the three groups(0.1235±0.0611 vs. 0.0280±0.0183, 0.1648±0.0571 vs. 0.0305±0.0208, 0.1702±0.0628 vs. 0.0298±0.0229)(P<0.05) and then decreased gradually. The L/M ratio of EN(0.0278±0.0217) and HIIC+EN(0.0336±0.0235) groups recovered to the baseline on POD+12, however HIIC+PN group still had elevated L/M ratio(0.0616±0.0430). The percentage of CD4(+)T cell and the ratio of CD4/CD8 in HIIC+EN group and HIIC+PN group were significantly lower than those in EN group(P=0.033, P=0.002, respectively). Compared with the POD-1,the percentage of CD4(+)T cell and the ratio of CD4/CD8 in HIIC+EN group and EN group on POD+12 were increased significantly(P<0.05). HIIC may cause significant increase in intestinal permeability and inhibit cellular immunity in patients undergoing radical resection for advanced gastric cancer. Mucosal permeability can be reversed by enteral nutrition.

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