Spatiotemporal modulation of SMAD4 by HBx is required for cellular proliferation in hepatitis B-related liver cancer.

PURPOSE: Hepatitis B virus (HBV) plays a crucial role in the progression of hepatocellular carcinoma (HCC). It is known that HBV-encoded X protein (HBx) can induce genetic alterations in some oncogenes and that SMAD4 is relevant for the development of some cancers, especially HBV-related HCC. Previously, it has been reported that HBx can promote SMAD4 protein expression in liver fibrosis and HCC but, as yet, its regulatory mechanism has not been fully elucidated. Here, we aimed to investigate the correlation between and regulatory mechanism behind HBx and SMAD4 in HCC. METHODS: mRNA and protein expression of SMAD4 in HCC tissues was detected by qRT-PCR, Western blotting and IHC. CCK-8 and colony forming assays, as well as xenograft murine models were used to evaluate the effects of HBx and SMAD4 on the proliferation and tumorigenicity of HCC cells. Luciferase reporter, immunofluorescence, Co-IP and truncation assays were performed to assess the regulatory relationship between HBx and SMAD4. RESULTS: We found that SMAD4 was highly expressed in HBV-positive HCC patient samples and correlated with a poor prognosis. The proliferation of HCC cells with a high SMAD4 expression was found to be enhanced in vitro and in vivo, and knocking down HBx while replenishing SMAD4 rescued HCC cell proliferation. Mechanically, we found that HBx regulates SMAD4 expression at the transcriptional level via TFII-I and can bind to SMAD4 to repress its ubiquitination. The binding region comprised the MH2 domain of SMAD4. Furthermore, we found that SMAD4 can promote HBx expression through a positive feedback mechanism. CONCLUSIONS: From our data we conclude that SMAD4 is modulated spatiotemporally via both transcriptional activation and protein stabilization by HBx in HCC cells. Our data shed light on the molecular mechanism underlying HBx-induced hepatocarcinogenesis.

The value of differential time to positivity of blood cultures in diagnosis of catheter-related bloodstream ;infection in patients with solid tumors in intensive care unit / 中华危重病急救医学

Objective To determine the value of differential time to positivity ( DTTP ) of blood culture for the diagnosis of catheter-related bloodstream infection ( CRBSI ) in patients with solid tumors in intensive care unit ( ICU ). Methods A retrospective study was conducted. 615 pairs of peripheral vein blood cultures and instantaneous catheter tip blood culture of 615 patients admitted to ICU of Tianjin Medical University Cancer Institute and Hospital were collected from August 2011 to March 2014. The DTTP method and ( or ) semi quantitative culture of catheter tip were compared. CRBSI was diagnosed when both cultures were positive for the same microorganism and DTTP ≥2 hours ( 120 minutes ). The result of this procedure was compared with that of organism obtained using the semi quantitative culture of blood at catheter tip with≥15 cfu. Based on the clinical diagnosis, the reliability of two kinds of laboratory examination was compared for the diagnosis of CRBSI by plotting receiver operator characteristic curve ( ROC curve ). Results The result of 615 cases suspected of having CRBSI were analyzed during the study period. Of these, 440 episodes were excluded because cultures were negative for blood obtained through peripheral vein and central vein. Eight episodes were excluded because only peripheral vein blood culture was positive and 57 episodes were excluded because of only central vein blood culture was positive, 68 pairs of blood cultures were excluded due to the presence of multiple catheters and repeated blood withdrawals. Two cases of polymicrobial cultures were excluded from the final analysis due to the difficulty in determining the time of positive result for each individual microorganism. Ten cases in 42 cases of suspected cases of CRBSI were excluded from analysis because catheter was not removed, therefore culture from catheter tip could not be obtained. Using the DTTP method, 14 out of 17 CRBSI cases were diagnosed with DTTP≥120 minutes, while 3 cases were missed;the semi quantitative catheter tip culture was positive in 13 cases, and in 4 cases it was neglected. In 2 cases of CRBSI it was missed by both methods. The area under the ROC curve ( AUC ) of DTTP, catheter tip culture and the combination method was 0.912, 0.882 and 0.941 for diagnosis of CRBSI, respectively. Validity values for the diagnosis of CRBSI for DTTP were:sensitivity 82.35%, specificity 92.31%, positive predictive value 93.33%and negative predictive value 80.00%, and they were higher than those of the catheter tip culture method only ( 76.47%, 84.62%, 86.67% and 73.33%). The specificity and positive predictive CRBSI combination of the two methods in the diagnosis value were up to 100%, the sensitivity ( 88.24%) and negative predictive value ( 86.67%) was also increased, but no significant differences were found with DTTP method (χ2=0.00, P=1.00;χ2=0.00, P=0.98;χ2=0.00, P=0.98;χ2=0.00, P=0.98 ). Conclusions DTTP can be a valid method recommended for CRBSI diagnosis in critically ill patients with acceptable sensitivity, good specificity as well as positive predictive value. DTTP combined with other clinical symptoms can not only avoid unnecessary catheter withdrawal, but it also can help obtain the optimal treatment time and strategy.

Clinical analysis of cancer patients with Pseudomonas aeruginosa bloodstream infections / 中国肿瘤临床

Objective:To analyze risk factors of cancer patients with Pseudomonas aeruginosa bloodstream infections and drug resistance. Methods:Clinical data of 30 cancer patients with P. aeruginosa bloodstream infection and 90 without infection who were ad-mitted in the Tianjin Medical University Cancer Institute and Hospital between January 2010 and December 2012 were retrospectively analyzed. Whonet 5.6 and SPSS19.0 software were used for statistical analysis of the data. Results:The infection group consisted of 20 male and 10 female patients with a mean age of 60.9±11.2 years. The control group consisted of 60 males and 30 females with a mean age of 51.3 ± 15.9 years. Multivariate logistic regression analysis showed that the number of hospitalization, combined with infection of other sites, and more than two types of antibiotics were independent risk factors of cancer patients with P. aeruginosa bloodstream infec-tions. P. aeruginosa showed high sensitivity(>80%) to carbapenems, ceftazidime, cefepime, aminoglycosides, and fluoroquinolones. The mortality rate of cancer patients with P. aeruginosa bloodstream infections was 60%. Conclusion:Cancer patients with P. aerugino-sa bloodstream infections have high mortality. Therefore, comprehensive prevention and control measures must be implemented in clini-cal practice to reduce P. aeruginosa bloodstream infections.