PO-181 Predicting homing ability of hepatocellular carcinoma cells by using a lab-on-a-chip system

Abstract

IntroductionThe core subunit of the COMPASS-like complex, WD Repeat Domain 5 (WDR5) has a prominent role in cell self-renewal, reprogramming and Epithelial-to-Mesenchymal transition (EMT) in different tumour types. We have identified WDR5 as an epigenetic target in in vivo and in vitro shRNA screenings performed in MCF10DCIS.com (from now MCF10DCIS) breast cancer (BC) cells. Here, we show that WDR5 can regulate metastasis dissemination in BC by stimulating TGFB-induced EMT.Material and methodsMCF10DCIS and MDAMB231 cells and six metastatic PDXs were used for in vivo and in vitro studies. Cells were transduced to silence WDR5 (shWDR5) or a neutral control (shLuc). Transcriptomic profiles were evaluated by RNA-seq in shLuc and shWDR5 PDXs and MCF10DCIS cells. Differentially expressed genes (DEGs) were identified using Log2FC>|0.6| and FDR<0.05. Chromatin Immunoprecipitation was performed to identify H3K4me3 binding in shLuc and shWDR5 MCF10DCIS cells. Peak calling was performed using MACS2.0 and peaks distribution was analysed within ±2.5 kbp from Transcription Start Sites (TSS) region of target genes. TGFB induction was obtained by 5 ng/ml TGFB-administration for 2 days in MCF10DCIS cells. Statistical analysis was performed by applying a Student t test for in vivo and in vitro experiments.Results and discussionsWDR5 interference significantly inhibited tumour growth and in vitro migration of PDXs and MCF10DCIS cells and reduced metastatic burden of MDAMB231 cells in vivo. These data suggested that WDR5 may be involved in cell motility, promoting invasiveness and metastasis. Gene Ontology performed on DEGs highlighted an enrichment of functions related to EMT and TGFB signalling. Indeed, protein and mRNA levels of a series of gene implicated in EMT (e.g. SNAI1, TWIST1, CDH2, SNAI2, ZEB1) were strongly reduced in shWDR5 PDXs and MCF10DCIS cells, thus suggesting a regulatory role of WDR5 in EMT. H3K4me3 levels were globally affected and concordantly reduced at TSS level of SNAI1 and TWIST1 genes in shWDR5 MCF10DCIS cells, confirming that WDR5 can transcriptionally regulate EMT in BC. Moreover, the induction of EMT by TGFB treatment can be abrogated in WDR5-deficient cells, suggesting that the EMT induced by TGFB is WDR5-dependent.ConclusionOur evidences support a model in which WDR5 is responsible for mediating the epithelial-to-mesenchymal transition and metastasis dissemination in BC. WDR5 is essential for TGFB response and its inhibition may be a successful approach to prevent progression of metastatic BC.