Global Gene Deregulations in FASN Silenced Retinoblastoma Cancer Cells: Molecular and Clinico-Pathological Correlations

• Published in: Journal of cellular biochemistry Vol. 116; no. 11; pp. 2676 - 2694
• Main Authors: Sangeetha, Manoharan, Deepa, Perinkulam Ravi, Rishi, Pukhraj, Khetan, Vikas, Krishnakumar, Subramanian
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.11.2015; Wiley Subscription Services, Inc
• Subjects: 1-Phosphatidylinositol 3-kinase; AKT protein; APOPTOSIS; Cancer; Cell cycle; Cell signaling; Cell Survival; Cell viability; Child; Child, Preschool; DE NOVO LIPOGENESIS; Deregulation; DNA microarrays; FATTY ACID SYNTHASE; Fatty Acid Synthase, Type I - genetics; Fatty Acid Synthase, Type I - metabolism; Fatty acids; Female; G protein-coupled receptors; Gene expression; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; GENE SILENCING; Genes; Humans; Infant; Lipid metabolism; Lipids; Lipogenesis; Male; MAP kinase; Metabolism; Oligonucleotide Array Sequence Analysis; Pediatrics; Phosphorylation; Proteins; Retina; Retinal Neoplasms - genetics; Retinal Neoplasms - metabolism; Retinal Neoplasms - pathology; RETINOBLASTOMA; Retinoblastoma - genetics; Retinoblastoma - metabolism; Retinoblastoma - pathology; Retinoid X receptor α; Signal Transduction; Signaling; siRNA; Survival; Tumors; APOPTOSIS; RETINOBLASTOMA; DE NOVO LIPOGENESIS; FATTY ACID SYNTHASE; GENE SILENCING
• ISSN: 0730-2312; 1097-4644
• DOI: 10.1002/jcb.25217

Activation of fatty acid synthase (FASN) enzyme in the de novo lipogenic pathway has been reported in various cancers including retinoblastoma (RB), a pediatric ocular cancer. The present study investigates lipogenesis‐dependent survival of RB cancer cells and the associated molecular pathways in FASN silenced RB cells. The siRNA‐mediated FASN gene knockdown in RB cancer cells (Y79, WERI RB1) repressed FASN mRNA and protein expressions, and decreased cancer cell viability. Global gene expression microarray analysis was performed in optimized FASN siRNA transfected and untransfected RB cells. Deregulation of various downstream cell signaling pathways such as EGFR (n = 55 genes), TGF‐beta (n = 45 genes), cell cycle (n = 41 genes), MAPK (n = 39 genes), lipid metabolism (n = 23 genes), apoptosis (n = 21 genes), GPCR signaling (n = 21 genes), and oxidative phosporylation (n = 18 genes) were observed. The qRT‐PCR validation in FASN knockdown RB cells revealed up‐regulation of ANXA1, DAPK2, and down‐regulation of SKP2, SREBP1c, RXRA, ACACB, FASN, HMGCR, USP2a genes that favored the anti‐cancer effect of lipogenic inhibition in RB. The expression of these genes in primary RB tumor tissues were correlated with FASN expression, based on their clinico‐pathological features. The differential phosphorylation status of the various PI3K/AKT pathway proteins (by western analysis) indicated that the FASN gene silencing indeed mediated apoptosis in RB cells through the PI3K/AKT pathway. Scratch assay clearly revealed that FASN silencing reduced the invading property of RB cancer cells. Dependence of RB cancer cells on lipid metabolism for survival and progression is implicated. Thus targeting FASN is a promising strategy in RB therapy. J. Cell. Biochem. 116: 2676–2694, 2015. © 2015 Wiley Periodicals, Inc.