Role of Adjuvant Treatment in High-risk Patients Following Resection for Gallbladder Cancer.

AIM: To identify prognostic factors for surgically resected gallbladder cancer (GBC). PATIENTS AND METHODS: Medical records of 66 patients with GBC undergoing potentially curative resection between 2001 and 2017 were retrospectively reviewed. RESULTS: After a median follow-up of 39.9 months (range=0.5-216.4 months), 22 locoregional recurrences and 25 distant metastases occurred. Adjuvant radiotherapy and adjuvant chemotherapy failed to prove efficacy in all patient groups. In patients with stage III-IV GBC, adjuvant chemotherapy showed a marginally positive effect on locoregional control (p=0.064), and was significantly beneficial for overall survival (p=0.040), and adjuvant treatment improved both locoregional control and overall survival (p=0.029 and p=0.005, respectively). On multivariate analysis, a negative resection margin was a significant prognostic factor for superior local control, and disease-free and overall survival (p=0.003, p=0.010 and p=0.005, respectively) and adjuvant treatment was associated with improved overall survival (p=0.018). CONCLUSION: Adjuvant treatment is recommended for patients with stage III-IV GBC following curative surgical resection.

Two intermediate states of the conformational switch in dual specificity phosphatase 13a.

Dual specificity phosphatases (DUSPs) include MAP kinase phosphatases and atypical dual specificity phosphatases and mediate cell growth and differentiation, brain function, and immune responses. They serve as targets for drug development against cancers, diabetes and depression. Several DUSPs have non-canonical conformation of the central ß-sheet and active site loops, suggesting that they may have conformational switch that is related to the regulation of enzyme activity. Here, we determined the crystal structure of DUSP13a, and identified two different structures that represent intermediates of the postulated conformational switch. Amino acid sequence of DUSP13a is not significantly homologous to DUSPs with conformational switch, indicating that the conformational switch is not sequence-dependent, but rather determined by ligand interaction. The sequence-independency suggests that other DUSPs with canonical conformation may have the conformational switch during specific cellular regulation. The conformational switch leads to significant changes in the protein surface, including a hydrophobic surface and pockets, which can be exploited for development of allosteric modulators of drug target DUSPs.

Structure of the catalytic domain of protein tyrosine phosphatase sigma in the sulfenic acid form.

Protein tyrosine phosphatase sigma (PTPσ) plays a vital role in neural development. The extracellular domain of PTPσ binds to various proteoglycans, which control the activity of 2 intracellular PTP domains (D1 and D2). To understand the regulatory mechanism of PTPσ, we carried out structural and biochemical analyses of PTPσ D1D2. In the crystal structure analysis of a mutant form of D1D2 of PTPσ, we unexpectedly found that the catalytic cysteine of D1 is oxidized to cysteine sulfenic acid, while that of D2 remained in its reduced form, suggesting that D1 is more sensitive to oxidation than D2. This finding contrasts previous observations on PTPα. The cysteine sulfenic acid of D1 was further confirmed by immunoblot and mass spectrometric analyses. The stabilization of the cysteine sulfenic acid in the active site of PTP suggests that the formation of cysteine sulfenic acid may function as a stable intermediate during the redox-regulation of PTPs.

Erratum to ''Characterization of the regulatory roles of the SUMO.

BACKGROUND: Type 1 diabetes is a multi-factorial autoimmune disease that results from the destruction of insulin-producing ß cells of the pancreas; both genetic and environmental factors are thought to contribute to its development. Recently, a novel gene encoding small ubiquitin-like modifier protein 4 (SUMO4) was cloned and a single nucleotide substitution (M55V) was found to be strongly associated with type 1 diabetes. SUMO4 was shown to interact with IκBα and inhibit NFκB transcriptional activity. The M55V substitution of SUMO4 may affect its ability to modify IκBα by sumoylation, and so lead to activation of NFκB and transcription of genes implicated in the development of type 1 diabetes. However, the effects of sumoylation on immune cells are poorly understood. METHODS: Human SUMO1, 2, 3, 4 and mouse SUMO2 (mSUMO2) were cloned and overexpressed in T and B cells using retroviral transduction. We then investigated whether SUMO overexpression affected their functions in vitro. To study the function of mSUMO2 in vivo, we made transgenic mice overexpressing mSUMO2 in T cells and pancreatic ß cells and compared them with transgenic mice expressing a super-repressor of NFκB (a dominant negative form of NFκB, IκBαΔN) in T cells. Diabetes was induced in the two groups of mice by i.p. injection of streptozotocin. RESULTS: Human SUMO1, 2, 3, 4 and mSUMO2 were all found to negatively regulate the transcriptional activity of T and B cells. Supporting this idea, mSUMO2 overexpression in T cells suppressed the production of both Th1 and Th2 cytokines unlike T cells from the IκBαΔN mice. However, transgenic mice overexpressing mSUMO2 had the same susceptibility to diabetes as wild type whereas the mice overexpressing IκBαΔN Tg were completely protected against diabetes. CONCLUSION: These results indicate that at least in T cells, whereas NFκB has pro-apoptotic activity, mSUMO2 plays a more complex role in the development of autoimmune diabetes. The relative influence of NFκB and sumoylation on the development of autoimmune diabetes in vivo may vary depending on the developmental stage and cell type.

Characterization of the regulatory roles of the SUMO.

BACKGROUND: Type 1 diabetes is a multi-factorial autoimmune disease that results from the destruction of insulin-producing ß cells of the pancreas; both genetic and environmental factors are thought to contribute to its development. Recently, a novel gene encoding small ubiquitin-like modifier protein 4 (SUMO4) was cloned and a single nucleotide substitution (M55V) was found to be strongly associated with type 1 diabetes. SUMO4 was shown to interact with IκBα and inhibit NFκB transcriptional activity. The M55V substitution of SUMO4 may affect its ability to modify IκBα by sumoylation, and so lead to activation of NFκB and transcription of genes implicated in the development of type 1 diabetes. However, the effects of sumoylation on immune cells are poorly understood. METHODS: Human SUMO1, 2, 3, 4 and mouse SUMO2 (mSUMO2) were cloned and overexpressed in dendritic, T and B cells using retroviral transduction. We then investigated whether SUMO overexpression affected their functions in vitro. To study the function of mSUMO2 in vivo, we made transgenic mice overexpressing mSUMO2 in T cells and pancreatic ß cells and compared them with transgenic mice expressing a super-repressor of NFκB (a dominant negative form of NFκB, IκBαΔN) in T cells. Diabetes was induced in the two groups of mice by i.p. injection of streptozotocin. RESULTS: Human SUMO1, 2, 3, 4 and mSUMO2 were all found to negatively regulate the transcriptional activity of T, B and dendritic cells. Although mSUMO2 overexpression in dendritic cells did not alter the expression of major histocompatibility complex class II proteins or B7, IL-1, IL-6 and IL-7, IL-12 expression decreased, switching Th1-directed immune responses into Th2 responses. Unlike T cells from the IκBαΔN mice, mSUMO2 overexpression in T cells suppressed the production of both Th1 and Th2 cytokines. Whereas the mice overexpressing IκBαΔN were completely protected against diabetes, those expressing mSUMO2 had the same susceptibility to diabetes as wild type. CONCLUSION: These results indicate that at least in T cells, whereas NFκB has pro-apoptotic activity, mSUMO2 plays a more complex role in the development of autoimmune diabetes. The relative influence of NFκB and sumoylation on the development of autoimmune diabetes in vivo may vary depending on the developmental stage and cell type.

Association of vascular endothelial growth factor polymorphisms with nonproliferative and proliferative diabetic retinopathy.

CONTEXT: Vascular endothelial growth factor (VEGF) is a potent angiogenic and vascular permeability factor, and its polymorphisms are associated with proliferative diabetic retinopathy (PDR) and macular edema. OBJECTIVE: We investigated the contributions of VEGF gene polymorphisms to nonproliferative diabetic retinopathy (NPDR) as well as PDR. DESIGN, SETTING, AND SUBJECTS: In this study we compared VEGF gene variants in a sample of Korean type 2 diabetes patients with and without diabetic retinopathy (DR) and in healthy controls. Of the diabetes patients, 145 had PDR, 108 had NPDR, and 134 had no retinopathy (noDR). They were all duration matched. Samples were genotyped for rs699947, rs1570360, and rs2010963 polymorphisms. RESULTS: We found a significant association between the A allele at rs699947 with DR (odds ratio = 1.84 (95% confidence interval = 1.28-2.66); P = 0.001 vs. noDR). Patients with NPDR, as well as PDR, had increased incidence of the A allele. The AGG haplotype was more frequently found in patients with DR than in patients with noDR (odds ratio = 4.79 (95% confidence interval = 1.42-16.16); P = 0.006). PDR and NPDR patients exhibited an increased incidence of the AGG haplotype. CONCLUSIONS: VEGF polymorphisms might be a useful predictive marker for the development and progression of DR at an earlier stage of diabetes.