The clinical association of programmed cell death protein 4(PDCD4) with solid tumors and its prognostic significance:a meta-analysis

Background: Programmed cell death protein 4(PDCD4) is a novel tumor suppressor protein involved in pro?grammed cell death. Its association with cancer progression has been observed in multiple tumor models, but evidence supporting its association with solid tumors in humans remains controversial. This study aimed to determine the clinical signiicance and prognostic value of PDCD4 in solid tumors.Methods: A systematic literature review was performed to retrieve publications with available clinical informa?tion and survival data. The eligibility of the selected articles was based on the criteria of the Dutch Cochrane Centre proposed by the Meta?analysis Of Observational Studies in Epidemiology group. Pooled odds ratios(ORs), hazard ratios(HRs), and 95% conidence intervals(CIs) for survival analysis were calculated. Publication bias was examined by Begg's and Egger's tests.Results: Clinical data of 2227 cancer patients with solid tumors from 23 studies were evaluated. PDCD4 expression was signiicantly associated with the diferentiation status of head and neck cancer(OR 4.25, 95% CI 1.87–9.66) and digestive system cancer(OR 2.87, 95% CI 1.84–4.48). Down?regulation of PDCD4 was signiicantly associated with short overall survival of patients with head and neck(HR: 3.44, 95% CI 2.38–4.98), breast(HR: 1.86, 95% CI 1.36–2.54), digestive system(HR: 2.12, 95% CI 1.75–2.56), and urinary system cancers(HR: 3.16, 95% CI 1.06–9.41).Conclusions: The current evidence suggests that PDCD4 down?regulation is involved in the progression of several types of solid tumor and is a potential marker for solid tumor prognoses. Its clinical usefulness should be conirmed by large?scale prospective studies.

PTEN and PDCD4 are Bona Fide Targets of microRNA-21 in Human Cholangiocarcinoma

Objective To investigate the expression profile of microRNA-21 in human cholangiocarcinoma tis- sues and to validate its bona fide targets in human cholangiocarcinoma cells. Methods The expression profile of microRNA-21 in human cholangiocarcinoma tissues and cholan- giocarcinoma cell line, QBC939, was evaluated by using real-time PCR analysis. The bona fide targets of microRNA-21 were analyzed and confirmed by dual luciferase reporter gene assay and western blot, respec- tively. The expressional correlation of microRNA-21 and its targets was probed in human cholangiocarci- noma tissues by using real-time PCR, locked nucleic acid in situ hybridization （LNA-ISH）, and immunohis- tochemistry analysis. Results Real-time PCR analysis revealed that microRNA-21 expression depicted a significant up-regulation in human cholangiocarcinoma tissues about 5.6-fold as compared to the matched normal bileduct tissues （P〈0.05）. The dual luciferase reporter gene assay revealed endogenous microRNA-21 in cholan- giocarcinoma cell line, QBC939, inhibited the luciferase reporter activities of wild-type PTEN （P〈0.01） and PDCD4 （P〈0.05） and had no this effect on mutated PTEN and PDCD4. Moreover, loss of microRNA-21 function led to a significant increase of PTEN and PDCD4 protein levels in QBC939 cells. Elevated microRNA-21 levels were accompanied by marked reductions of PTEN and PDCD4 expression in the same cholangiocarcinoma tissue. Conclusion microRNA-21 expression is up PDCD4 are direct effectors of microRNA-21. regulated in human cholangiocarcinoma and PTEN,