Reduced p21WAF1/CIP1 via Alteration of p53-DDX3 Pathway Is Associated with Poor Relapse-Free Survival in Early-Stage Human Papillomavirus–Associated Lung Cancer

Abstract

Purpose: DDX3 alteration has been shown to participate in hepatocellular tumorigenesis via p21 WAF1/CIP1 (p21) deregulation. We observed that DDX3 and p21 expression in lung tumors was negatively associated with E6 expression. Therefore, the aim of this study was to clarify whether deregulation of p21 by DDX3 via an E6-inactivated p53 pathway would enhance tumor progression in HPV-associated lung cancers. Experimental Design: Real-time PCR, luciferase assays, immunoprecipitation, and chromatin immunoprecipitation (ChIP) were performed to determine whether DDX3 was regulated by p53 to synergistically enhance p21 transcriptional activity. Cell proliferation was examined by cell counting and colony formation assays. DDX3 and p21 expression were evaluated in 138 lung tumors by real-time PCR and immunohistochemistry. The prognostic value of p21 expression on relapse-free survival (RFS) was analyzed by Kaplan-Meier analysis.Results: Real-time PCR, luciferase assays, and ChIP assays indicated that three putative p53 binding sites, located at À1,080/À1,070, À695/À685, and À283/À273 on the DDX3 promoter, were required for DDX3 transcription. DDX3 deregulation by the E6-inactivated p53 pathway could promote cell proliferation and the ability to form colonies via reduced Sp1 binding activity on the p21 promoter. Among tumors, p21 expression was positively associated with DDX3 expression and negatively related with E6 expression, particularly in early-stage (I þ II) tumors. Interestingly, low p21 expression was associated with a poor RFS in early-stage lung cancer.Conclusion: The reduction of p21 by the alteration of the p53-DDX3 pathway plays an essential role in early-stage HPV-associated lung tumorigenesis and is correlated with poor RFS of lung cancer patients. Clin Cancer Res; 17(7); 1895-905. Ó2011 AACR.

IL-10 Promotes Tumor Aggressiveness via Upregulation of CIP2A Transcription in Lung Adenocarcinoma

“…18,19). Median survival time and 5-year survival rate for the whole-test set were estimated using the Kaplan-Meier product limit method.…”

“…The expression vector of HPV16 E6 and RNA interference target sequences for HPV16 E6 shRNA have been previously verified (18). Nonspecific shRNA control (NC) of scramble sequence was used as the control in the knockdown experiment and vector control (VC) was used as the control of HPV E6 overexpression.…”

“…The procedures and methods were as described previously (18). In anchorage-independent soft agar growth assay, the colonies larger than 150 mm in diameter were counted.…”

“…Chromatin immunoprecipitation (ChIP) analysis was conducted as described in previous reports (18). The primers are listed in Supplementary Table S1.…”

Expression and prognostic significance of cyclin‑dependent kinase inhibitor 1A in patients with resected gastric adenocarcinoma

“…Certain studies have identified that CDKN1A overexpression in cancer tissues is associated with tumor aggressiveness and poor survival: Dai et al (29) suggested that CDKN1A expression in breast cancer tissues was correlated with LNM and poor survival of patients with breast cancer, and increased MDA-MB231 breast cancer cell migration and invasion via transforming growth factor β-mediated mothers against decapentaplegic homolog 3 acetylation. In addition to the aforementioned studies (4,(22)(23)(24)(25)(26)(27), there have been other investigations indicating that low expression of CDKN1A in various cancer tissues is associated with poor prognosis (30,31). The molecular mechanism by which different CDKN1A expression levels affect prognoses in patients with different types of cancer remains unclear and requires additional investigation.…”