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Ubiquitin specific protease 35 (USP35) is a member of deubiquitylases (DUBs). It remains largely unknown about the biological role and the regulation mechanism of USP35. Here, we first identified miR let-7a as a positive regulator of USP35 expression and showed that USP35 expression positively correlates with miR let-7a expression in different cancer cell lines and tissues. Then, we showed that USP35 expression was decreased dramatically in the tumor tissues compared with the adjacent non-cancerous tissues. USP35 overexpression inhibited cell proliferation in vitro and inhibited xenograft tumor growth in vivo. Furthermore, we revealed that USP35 acts as a functional DUB and stabilizes TNFAIP3 interacting protein 2 (ABIN-2) by promoting its deubiquitination. Functionally, both ABIN-2 and USP35 could inhibit TNFα-induced NF-κB activation and overexpression of ABIN-2 alleviated USP35-loss induced activation of NF-κB. Collectively, our data indicated that miR let-7a-regulated USP35 can inhibit NF-κB activation by deubiquitination and stabilization of ABIN-2 protein and eventually inhibit cell proliferation. Overall, our study provides a novel rationale of targeting miR let-7a-USP35-ABIN-2 pathway for the therapy of cancer patients.

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Systemic lupus erythematosus (SLE) predominantly affects women of childbearing age, but 15-20% of cases are diagnosed during childhood. It is important for physicians to understand the epidemiology and clinical presentation for early detection and diagnosis of this disease in difference races. The aim of this retrospective review was to provide a 20-year experience for initial clinical and laboratory manifestations and outcomes in pediatric-onset SLE (pSLE) in a medical center in Asia. We reviewed medical records between April 1990 and June 2012 of patients with a diagnosis of International Classification of Diseases, Ninth Revision (ICD-9) code 710.0 (SLE), who admitted or received follow-up in the Department of Pediatrics at Chang Chung Memorial Hospital. Patients with a diagnosis of SLE prior to their 18th birthday and followed up at our hospital were eligible for inclusion in this study. Medical records regarding age, gender, date of birth and diagnosis, clinical manifestations at diagnosis, laboratory results, image studies and the classification criteria were reviewed. Patients received regular outpatient department follow-up and laboratory survey every 1-6 months. The study cohort consisted of 189 patients; 164 females (86.87%) and 25 males (13.23%). The overall mean age at pSLE diagnosis was 12.62 ± 2.77 years. The most common clinical symptom was malar rash, followed by arthritis and oral ulcers. There was no significant difference in clinical and laboratory manifestations between females and males. More than half of the patients presented with renal involvement initially. The most common histological finding was Class IV lupus nephritis (LN), especially in males (p = 0.034) and young age. Even with severe LN, the rate of end-stage renal disease (ESRD) was low if adequate treatment was initiated. The 5, 10 and 15-year ESRD-free survival rates were 95.4%, 94.0% and 89.9% in patients with biopsy-proven LN. However, infection was the leading cause of mortality. Therefore, aggressive treatment for major organ involvement is important, but physicians must also be aware of fatal infection. The overall survival rates were 5 years: 93.4% and 10-20 years: 89.6%.

Background:CD44, a transmembrane glycoprotein expressed in a variety of cells and tissues, has been implicated in tumour metastasis. But the molecular mechanisms of CD44-mediated tumour cell metastasis remain to be elucidated.Methods:The downregulation of CD44 was determined by immunofluorescence. Moreover, the motility of breast cancer cells was detected by wound-healing and transwell experiments. Then the spontaneous metastasis of CD44-silenced MDA-MB-231 cells was tested by histology with BALB/c nude mice.Results:A positive correlation between CD44 and Na+/H+ exchanger isoform 1 (NHE1) was found in two breast cancer cells. CD44 downregulation could inhibit the metastasis of MDA-MB-231 cells and the expressions of Na+/H+ exchanger 1. Moreover, CD44 overexpression upregulated the metastasis of MCF-7 cells, but the elevated metastatic ability was then inhibited by Cariporide. Interestingly, during these processes only the p-ERK1/2 was suppressed by CD44 downregulation and the expression of matrix metalloproteinases and metastatic capacity of MDA-MB-231 cells were greatly inhibited by the MEK1 inhibitor PD98059, which even had a synergistic effect with Cariporide. Furthermore, CD44 downregulation inhibits breast tumour outgrowth and spontaneous lung metastasis.Conclusions:Taken together, this work indicates that CD44 regulates the metastasis of breast cancer cells through regulating NHE1 expression, which could be used as a novel strategy for breast cancer therapy.

The interaction between calcineurin B homologous protein 2 (CHP2) and Na + ⁄ H + exchanger 1 (NHE1), two membrane proteins, is essential for protecting cells from serum deprivationinduced death. Although four putative EF-hands in CHP2 had been predicted for years, Ca 2+ -binding activities of these motifs have not been tested yet, their role in this process remain poorly understood. To identify Ca 2+ -binding motifs required for the stable formation of CHP2 ⁄ NHE1 complexes, we developed a mutagenesis-based assay in PS120 cells. We found that 45 Ca 2+ bond to two EF-hand motifs (EF3 and 4) of CHP2 proteins with high affinity. Complex formation between CHP2 and the CHP2 binding domain of NHE1 resulted in a marked increase in the Ca 2+ -binding affinity of CHP2. Co-immunoprecipitation and distribution of GFP-tagged CHP2-EF3m ⁄ 4m also indicated that Ca 2+ affected the membrane location of CHP2 to interact with NHE1. The C-terminal region of CHP2 contains a nuclear export sequence (NES). When the six leucines of NES were mutated to alanines, the resulting CHP2 protein was predominantly localized to the nucleus. Furthermore, mutation of the NES resulted in enhanced proliferation and oncogenic potential of HeLa cells. Together, these results show that calcium and NES control the subcellular distribution of CHP2 and then distinctively regulate cell proliferation.

SIRT2, one of nicotinamide adenine dinucleotide (NAD+)-dependent class Ⅲ histone deacetylase family proteins, has been found to be involved in the proliferation and survival of acute myeloid leukemia (AML) cells. However, its effect on drug resistance on chemoresistant AML cells is unclear. In the present study, we first found that SIRT2 was expressed at higher level in the relapsed AML patients than the newly diagnosed patients. Consistent with this observation, the expression level of SIRT2 was higher in HL60/A cells than that in HL60 cells. Depletion of SIRT2 by shRNAs in HL60/A cells resulted in decreased MRP1 level, enhanced drug accumulation and triggered more apoptosis. By contrast, overexpression of SIRT2 in HL60 cells led to increased MRP1 level, drug efflux and attenuated drug sensitivity. Moreover, the decreased expression of phosphorylated ERK1/2 was detected in SIRT2-depleted HL60/A cells and increased expression of phosphorylated ERK1/2 was observed in SIRT2 overexpressed HL60 cells. Furthermore, blockage of ERK1/2 signaling pathway with the chemical inhibitor PD98059, further induced apoptosis of HL60/A cells conferred by SIRT2 depletion. Importantly, ERK1/2 inhibition was able to reverse the drug resistance of HL60 conferred by SIRT2 overexpression. Thus, our findings collectively suggested that the expression level of SIRT2 has a positive relationship with DNR/Ara-C resistance and activity of ERK1/2 signaling pathway. SIRT2 might regulate DNR/Ara-C sensitivity in AML cells at least partially through the ERK1/2 pathway.