Phospholipid Phosphatase 4 promotes proliferation and tumorigenesis, and activates Ca2+-permeable Cationic Channel in lung carcinoma cells
MOLECULAR CANCER
Authors: Zhang, Xin; Zhang, Lan; Lin, Bihua; Chai, Xingxing; Li, Ronggang; Liao, Yuehua; Deng, Xinghui; Liu, Qiongru; Yang, Wenli; Cai, Yubo; Zhou, Wei; Lin, Zhichao; Huang, Wenhai; Zhong, Meigong; Lei, Fangyong; Wu, Jinhua; Yu, Shuaishuai; Li, Xiaoping; Li, Shangren; Li, Yueyue; Zeng, Jincheng; Long, Wansheng; Ren, Dong; Huang, Yanming
Abstract
Background: Phospholipid phosphatase 4 (PPAPDC1A or PLPP4) has been demonstrated to be involved in the malignant process of many cancers. The purpose of this study was to investigate the clinical significance and biological roles of PLPP4 in lung carcinoma. Methods: PLPP4 expression was examined in 8 paired lung carcinoma tissues by real-time PCR and in 265 lung carcinoma tissues by immunohistochemistry (IHC). Statistical analysis was performed to evaluate the clinical correlation between PLPP4 expression and clinicopathological features and survival in lung carcinoma patients. In vitro and in vivo assays were performed to assess the biological roles of PLPP4 in lung carcinoma. Fluorescence-activated cell sorting, Western blotting and luciferase assays were used to identify the underlying pathway through which PLPP4 silencing mediates biological roles in lung carcinoma. Results: PLPP4 is differentially elevated in lung adenocarcinoma (ADC) and lung squamous cell carcinoma (SQC) tissues. Statistical analysis demonstrated that high expression of PLPP4 significantly and positively correlated with clinicopathological features, including pathological grade, T category and stage, and poor overall and progression-free survival in lung carcinoma patients. Silencing PLPP4 inhibits proliferation and cell cycle progression in vitro and tumorigenesis in vivo in lung carcinoma cells. Our results further reveal that PLPP4 silencing inhibits Ca2+-permeable cationic channel, suggesting that downregulation of PLPP4 inhibits proliferation and tumorigenesis in lung carcinoma cells via reducing the influx of intracellular Ca2+. Conclusion: Our results indicate that PLPP4 may hold promise as a novel marker for the diagnosis of lung carcinoma and as a potential therapeutic target to facilitate the development of novel treatment for lung carcinoma.
Genome-Wide Association Study of Cardiac Structure and Systolic Function in African Americans The Candidate Gene Association Resource (CARe) Study
CIRCULATION-CARDIOVASCULAR GENETICS
Authors: Fox, Ervin R.; Musani, Solomon K.; Barbalic, Maja; Lin, Honghuang; Yu, Bing; Ogunyankin, Kofo O.; Smith, Nicholas L.; Kutlar, Abdullah; Glazer, Nicole L.; Post, Wendy S.; Paltoo, Dina N.; Dries, Daniel L.; Farlow, Deborah N.; Duarte, Christine W.; Kardia, Sharon L.; Meyers, Kristin J.; Sun, Yan V.; Arnett, Donna K.; Patki, Amit A.; Sha, Jin; Cui, Xiangqui; Samdarshi, Tandaw E.; Penman, Alan D.; Bibbins-Domingo, Kirsten; Buzkova, Petra; Benjamin, Emelia J.; Bluemke, David A.; Morrison, Alanna C.; Heiss, Gerardo; Carr, J. Jeffrey; Tracy, Russell P.; Mosley, Thomas H.; Taylor, Herman A.; Psaty, Bruce M.; Heckbert, Susan R.; Cappola, Thomas P.; Vasan, Ramachandran S.
Abstract
Background-Using data from 4 community-based cohorts of African Americans, we tested the association between genome-wide markers (single-nucleotide polymorphisms) and cardiac phenotypes in the Candidate-gene Association Resource study. Methods and Results-Among 6765 African Americans, we related age, sex, height, and weight-adjusted residuals for 9 cardiac phenotypes (assessed by echocardiogram or magnetic resonance imaging) to 2.5 million single-nucleotide polymorphisms genotyped using Genome-wide Affymetrix Human SNP Array 6.0 (Affy6.0) and the remainder imputed. Within the cohort, genome-wide association analysis was conducted, followed by meta-analysis across cohorts using inverse variance weights (genome-wide significance threshold=4.0x10(-7)). Supplementary pathway analysis was performed. We attempted replication in 3 smaller cohorts of African ancestry and tested lookups in 1 consortium of European ancestry (EchoGEN). Across the 9 phenotypes, variants in 4 genetic loci reached genome-wide significance: rs4552931 in UBE2V2 (P=1.43x10(-7)) for left ventricular mass, rs7213314 in WIPI1 (P=1.68x10(-7)) for left ventricular internal diastolic diameter, rs1571099 in PPAPDC1A (P=2.57x10(-8)) for interventricular septal wall thickness, and rs9530176 in KLF5 (P=4.02x10(-7)) for ejection fraction. Associated variants were enriched in 3 signaling pathways involved in cardiac remodeling. None of the 4 loci replicated in cohorts of African ancestry was confirmed in lookups in EchoGEN. Conclusions-In the largest genome-wide association study of cardiac structure and function to date in African Americans, we identified 4 genetic loci related to left ventricular mass, interventricular septal wall thickness, left ventricular internal diastolic diameter, and ejection fraction, which reached genome-wide significance. Replication results suggest that these loci may be unique to individuals of African ancestry. Additional large-scale studies are warranted for these complex phenotypes. (Circ Cardiovasc Genet. 2013;6:37-46.)