Gene expression profiling of tumor stroma interactions in retinoblastoma

Abstract

We aimed to identify the critical molecular pathways altered upon tumor stroma interactions in retinoblastoma (RB). In vitro 2 D cocultures of RB tumor cells (Weri-Rb-1 and NCC-RbC-51) with primary bone marrow stromal cells (BMSC) was established. Global gene expression patterns in coculture samples were assessed using Affymetrix Prime view human gene chip microarray and followed with bioinformatics analyses. Key upregulated genes from Weri-Rb-1 + BMSC and NCC-RbC-51 + BMSC coculture were validated using qRT-PCR to ascertain their role in RB progression. Whole genome microarray experiments identified significant (P ≤ 0.05, 1.1 log 2 FC) transcriptome level changes induced upon coculture of RB cells with BMSC. A total of 1155 genes were downregulated and 1083 upregulated in Weri-Rb-1 + BMSC coculture. Similarly, 1865 genes showed downregulation and 1644 genes were upregulation in NCC-RbC-51 + BMSC coculture. The upregulated genes were significantly associated with pathways of focal adhesion, PI3K-Akt signalling, ECM-receptor interaction, JAK-STAT, TGF-β signalling thus contributing to RB progression. Validation of key genes by qRT-PCR revealed significant overexpression of IL8, IL6, MYC and SMAD3 in the case of Weri-Rb-1 + BMSC coculture and IL6 in the case of NCC-RbC-51 + BMSC coculture. The microarray expression study on in vitro RB coculture models revealed the pathways that could be involved in the progression of RB. The gene signature obtained in a stimulated model when a growing tumor interacts with its microenvironment may provide new horizons for potential targeted therapy in RB.

Keywords: Coculture; Microarray; Retinoblastoma; Tumor microenvironment; Tumor progression.