Inverse expression of survivin and reprimo correlates with poor patient prognosis in gastric cancer
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Paulina Cerda-Opazo1,2,3, Manuel Valenzuela-Valderrama1,4, Ignacio Wichmann2,3,9, Andrés Rodríguez2,3, Daniel Contreras-Reyes2,3, Elmer A. Fernández5,6,7, Gonzalo Carrasco-Aviño3,8, Alejandro H. Corvalán2,3,9 and Andrew F.G. Quest1,3
1Laboratorio de Comunicaciones Celulares, Centro de Estudios en Ejercicio, Metabolismo y Cáncer (CEMC), Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad De Medicina, Universidad de Chile, Santiago, Chile
2Gastric Cancer Research Group - Laboratory of Oncology, UC Center for Investigational Oncology (CITO), Pontificia Universidad Católica de Chile, Santiago, Chile
3Advanced Center for Chronic Diseases (ACCDiS), Santiago, Chile
4Facultad de Ciencias de la Salud, Universidad Central de Chile, Santiago, Chile
5CIDIE – CONICET - Facultad de Ingeniería, Campus Universitario, Universidad Católica de Córdoba, Córdoba, Argentina
6Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
7National Bioinformatics Consortia (BIA) of Argentina, Buenos Aires, Argentina
8Departamento de Anatomía Patológica, Hospital Clínico José Joaquín Aguirre, Universidad de Chile, Santiago, Chile
9Core Biodata, Advanced Center for Chronic Diseases (ACCDiS), Santiago, Chile
Alejandro H. Corvalán, email: firstname.lastname@example.org
Andrew F.G. Quest, email: email@example.com
Keywords: gastric cancer; survivin; reprimo; TCGA
Received: June 27, 2017 Accepted: January 24, 2018 Published: February 05, 2018
BACKGROUND: The objective of the study was to determine the relationship between Survivin and Reprimo transcript/protein expression levels, and gastric cancer outcome.
METHODS: In silico correlations between an agnostic set of twelve p53-dependent apoptosis and cell-cycle genes were explored in the gastric adenocarcinoma TCGA database, using cBioPortal. Findings were validated by regression analysis of RNAseq data. Separate regression analyses were performed to assess the impact of p53 status on Survivin and Reprimo. Quantitative reverse-transcription PCR (RT-qPCR) and immunohistochemistry confirmed in silico findings on fresh-frozen and paraffin-embedded gastric cancer tissues, respectively. Wild-type (AGS, SNU-1) and mutated p53 (NCI-N87) cell lines transfected with pEGFP-Survivin or pCMV6-Reprimo were evaluated by RT-qPCR and Western blotting. Kaplan-Meier method and Long-Rank test were used to assess differences in patient outcome.
RESULTS: cBioPortal analysis revealed an inverse correlation between Survivin and Reprimo expression (Pearson’s r= -0.3, Spearman’s ρ= -0.55). RNAseq analyses confirmed these findings (Spearman’s ρ= -0.37, p<4.2e-09) and revealed p53 dependence in linear regression models (p<0.05). mRNA and protein levels validated these observations in clinical samples (p<0.001). In vitro analysis in cell lines demonstrated that increasing Survivin reduced Reprimo, while increasing Reprimo reduced Survivin expression, but only did so in p53 wild-type gastric cells (p<0.05). Survivin-positive but Reprimo-negative patients displayed shorter overall survival rates (p=0.047, Long Rank Test) (HR=0.32; 95%IC: 0.11-0.97; p=0.044).
CONCLUSIONS: TCGA RNAseq data analysis, evaluation of clinical samples and studies in cell lines identified an inverse relationship between Survivin and Reprimo. Elevated Survivin and reduced Reprimo protein expression correlated with poor patient prognosis in gastric cancer.
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