Colorectal cancer (CRC) accounts for one of the highest cancer-associated mortalities worldwide. While scientific/clinical advancements have significantly improved survival of early stage CRC patients (~60-80%), patients with metastatic CRC (mCRC) have a dramatically low survival rate, with only 14% survival post-5 years of diagnosis. Suitable approaches to predict metastatic progression of CRC and further personalise treatment are severely lacking. We have identified a novel tumour-specific DNA methylation signature comprising of 376 differentially methylated regions (DMRs) derived from stage IV mCRC patients (discovery cohort). These DMRs largely encompass enhancer regions which potentially regulate genes impacting metastatic progression. This multidisciplinary research project aims to examine the ability of this novel signature to predict metastatic progression in CRC patients and in parallel elucidate its functional impact on processes underpinning development of a metastatic phenotype. To this end, we will identify methylation regions from the signature that can predict metastatic progression in CRC, by applying targeted methylation sequencing to two distinct stage III CRC patient cohorts: metastatic recurrence vs non-recurrence followed by comparing methylation status of all 376-DMRs between these two cohorts and the original stage IV mCRC discovery cohort. Next, we will carry out a CRISPRi loss-of-function screen for all the 376-DMRs in SW480 CRC cell line, followed by segregation of transduced cells in Matrigel chambers. This will enable us to identify specific loci that accelerates/impedes invasion potential of CRC cells. Further independent validation in an additional CRC cell line followed by RNAsequencing post-knock down of top 5 validated loci, will allow identification of signalling pathways that are regulated by these regions. Thus, confirming the ability of this signature to predict early metastatic progression in CRC, will ultimately enable identification of patients who require intensive treatment and conversely identify low risk patients who can be spared of unnecessary side effects of ineffective treatment.
