title: Global gene deregulations in FASN silenced retinoblastoma cancer cells: molecular and clinico-pathological correlations.
abstract: 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.
authors.affiliation: Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani, Rajasthan, India.|L and T Department of Ocular Pathology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India.
authors.forename: Manoharan
authors.initials: M
authors.lastname: Sangeetha
authors.affiliation: Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani, Rajasthan, India.
authors.forename: Perinkulam Ravi
authors.initials: PR
authors.lastname: Deepa
authors.affiliation: Shri Bhagwan Mahavir Department of Vitreoretinal Services, Medical Research Foundation, Sankara Nethralaya, 18, College Road, Chennai, Tamil Nadu, India.
authors.forename: Pukhraj
authors.initials: P
authors.lastname: Rishi
authors.affiliation: Shri Bhagwan Mahavir Department of Vitreoretinal Services, Medical Research Foundation, Sankara Nethralaya, 18, College Road, Chennai, Tamil Nadu, India.
authors.forename: Vikas
authors.initials: V
authors.lastname: Khetan
authors.affiliation: L and T Department of Ocular Pathology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India.
authors.forename: Subramanian
authors.initials: S
authors.lastname: Krishnakumar
mesh_terms: D002470:Cell Survival; D002648:Child; D002675:Child, Preschool; D054890:Fatty Acid Synthase, Type I / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D006801:Humans; D007223:Infant; D050155:Lipogenesis; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D019572:Retinal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D012175:Retinoblastoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D015398:Signal Transduction
chemical_list: C518729:FASN protein, human; D054890:Fatty Acid Synthase, Type I
keywords: APOPTOSIS; DE NOVO LIPOGENESIS; FATTY ACID SYNTHASE; GENE SILENCING; RETINOBLASTOMA