SUMO-specific protease 6 promotes gastric cancer cell growth via deSUMOylation of FoxM1.

SUMOylation is a post-translational modification exerted various effects on the target proteins. SUMOylation is a highly dynamic and reversible process, which has been shown to play an important role in tumorigenesis. However, the roles of sentrin/SUMO-specific proteases (SENPs), which mediate the reverse process of SUMOylation, in tumorigenesis remains largely unexplored. Here, we uncover a critical role of SENP6 in promoting gastric cancer cells growth via regulating the deSUMOylation of a transcription factor forkhead box protein M1 (FoxM1). We demonstrated that the mRNA and protein levels were elevated in gastric cancer tissues. Overexpression of SENP6 promoted, while RNA interference depletion of endogenous SENP6 inhibited gastric cancer cells growth and the ability of colony formation. By using biochemical assays, we identified FoxM1 as a novel substrate of SENP6 in gastric cancer cells. Thus, our data suggest that SENP6, which is highly expressed in gastric cancer cells, regulates the transcriptional activity and stability of FoxM1 through deSUMOylation.

[Clinical values of detecting excision repair cross complementing 1 and top-isomerase I in individualized therapies of metastatic colorectal cancer].

OBJECTIVE: To explore the clinical values of detecting drug related molecules excision repair cross complementing 1 (ERCC1) and top-isomerase I (TOPO I) in individualized therapies of metastatic colorectal cancer. METHODS: From June 2009 to December 2011, 90 patients at Huadong Hospital with metastatic colorectal cancer were randomly separated into 2 groups after operation. Each group had 45 patients without difference in gender, age or TNM stage. The expressions of ERCC1 and TOPO Iin cancer tissues were detected by immunohistochemical staining. The testing group received individualized chemotherapies following the expression results while the control group had random chemotherapies. The survival difference between two groups was analyzed by log-rank test and Kaplan-Meier analysis. And curative effect was analyzed by χ(2) or Fisher's analysis. RESULTS: The expressions of ERCC1 and TOPO I had no statistical significance between two groups (both P > 0.05). In the testing group, the median survival time was 281 days and the beneficial ratio 51.1% (23/45) versus 246 days and 44.4% (20/45) respectively in the control group. The inter-group comparisons of survival (P = 0.235) and curative effect (χ(2) = 0.04, P > 0.05) showed no statistical significance. In the estimated drug tolerated group (ERCC1 high expression or TOPO I low expression), the median survival time was 196 days and the beneficial ratio 4/14 versus 304 days and 51.3% (39/76) in the estimated drug sensitive group. The inter-group comparisons of survival and curative effect (both P < 0.05) had statistical significance. The median survival time and beneficial ratio significantly increased in estimated drug sensitive group than those in estimated drug tolerated group. CONCLUSIONS: The expression of drug related molecule in colorectal cancer tissue is significantly associated with curative effect in patients. Patients with down-regulated ERCC1 on Oxaliplatin or up-regulated TOPO Ion Irinotecan have longer survival and better curative effect. And chemotherapies guided by drug related molecule detection may boost curative effects in metastatic colorectal cancer.

Therapeutic efficacy of high-dose vitamin C on acute pancreatitis and its potential mechanisms.

AIM: To observe the therapeutic efficacy of high-dose Vitamin C (Vit. C) on acute pancreatitis (AP), and to explore its potential mechanisms. METHODS: Eighty-four AP patients were divided into treatment group and control group, 40 healthy subjects were taken as a normal group. In the treatment group, Vit. C (10 g/day) was given intravenously for 5 days, whereas in the control group, Vit. C (1 g/day) was given intravenously for 5 days. Symptoms, physical signs, duration of hospitalization, complications and mortality rate were monitored. Meanwhile, serum amylase, urine amylase and leukocyte counts were also determined. The concentration of plasma vitamin C (P-VC), plasma lipid peroxide (P-LPO), plasma vitamin E (P-VE), plasma beta-carotene (P-beta-CAR), whole blood glutathione (WB-GSH) and the activity of erythrocyte surperoxide dimutase (E-SOD) and erythrocyte catalase (E-CAT) as well as T lymphocyte phenotype were measured by spectrophotometry in the normal group and before and after treatment with Vit. C in the treatment and the control group. RESULTS: Compared with the normal group, the average values of P-VC, P-VE, P-beta-CAR, WB-GSH and the activity of E-SOD and E-CAT in AP patients were significantly decreased and the average value of P-LPO was significantly increased, especially in severe acute pancreatitis (SAP) patients (P<0.05. P-VC, P=0.045; P-VE, P=0.038; P=0.041; P-beta-CAR, P=0.046; WB-GSH, P=0.039; E-SOD, P=0.019; E-CAT, P=0.020; P-LPO, P=0.038). Compared with the normal group, CD3 and CD4 positive cells in AP patients were significantly decreased. The ratio of CD4/CD8 and CD4 positive cells were decreased, especially in SAP patients (P<0.05. CD4/CD8, P=0.041; CD4, P =0.019). Fever and vomiting disappeared, and leukocyte counts and amylase in urine and blood become normal quicker in the treatment group than in the control group. Moreover, patients in treatment group also had a higher cure rate, a lower complication rate and a shorter in-ward days compared with those in he control group. After treatment, the average value of P-VC was significantly higher and the values of SIL-2R, TNF-alpha, IL-6 and IL-8 were significantly lower in the treatment group than in the control group (P<0.05 P-VC, P=0.045; SIL-2R, P=0.012; TNF-alpha, P=0.030; IL-6, P=0.015; and IL-8, P=0.043). In addition, the ratio of CD4/CD8 and CD4 positive cells in the patients of treatment group were significantly higher than that of the control group after treatment (P<0.05. CD4/CD8, P=0.039; CD4, P=0.024). CONCLUSION: High-dose vitamin C has therapeutic efficacy on acute pancreatitis. The potential mechanisms include promotion of anti-oxidizing ability of AP patients, blocking of lipid peroxidation in the plasma and improvement of cellular immune function.