Despite improvements in participation in population-based screening programme, colorectal cancer remains a major cause of cancer-related mortality worldwide. Targeted interventions are desirable to reduce the health and economic burden of this disease. Two-dimensional monolayers of colorectal cancer cell lines represent the traditional in vitro models for disease and are often used for diverse purposes, including the delineation of molecular pathways associated with disease aetiology or the gauging of drug efficacy. The lack of complexity in such models, chiefly the limited epithelial cell diversity and differentiation, attenuated mucus production, lack of microbial interactions and mechanical stresses, has driven interest in the development of more holistic and physiologically relevant in vitro model systems. In particular, established ex vivo patient-derived explant and patient-derived tumour xenograft models have been supplemented by progress in organoid and microfluidic organ-on-a-chip cultures. Here, we discuss the applicability of advanced culturing technologies, such as organoid systems, as models for colorectal cancer and for testing chemotherapeutic drug sensitivity and efficacy. We highlight current challenges associated with organoid technologies and discuss their future for more accurate disease modelling and personalized medicine.

Current systemic therapies for advanced colorectal cancer (CRC) have limited efficacy, so more effective strategies for the treatment and prevention of CRC are needed. The majority of colorectal cancers are initiated by mutations in Wnt signalling pathway genes, including mutations in the APC gene, which result in a truncated APC protein and lead to excess signalling from β-catenin and the formation of pre-cancerous adenomas. The aim of this study was to determine if targeting the Wnt pathway in combination with pro-apoptotic mimetics altered the proliferative capacity or viability of human colorectal adenoma cells. Patient-derived colorectal adenoma organoid cultures were established from colon adenoma tissue collected by colonoscopy and recapitulated the histopathology of primary colorectal adenoma tissue. The growth of colorectal adenoma organoids is inhibited by the Wnt-signalling antagonist pyrvinium pamoate (PP) and a pro-apoptotic inhibitor of BCL-XL but not BCL-2 (venetoclax) or MCL-1 inhibitors. At low concentrations, the PP and the BCL-XL inhibitor combination demonstrated potent synergy and induced apoptosis in APC-defective patient-derived adenoma organoids, even in the presence of oncogenic KRAS or BRAF mutations, providing a new strategy for colon cancer prevention.

Despite improvements in participation in population-based screening programs, colorectal cancer remains a major cause of cancer-related mortality worldwide. Targeted interventions are desirable to reduce the health and economic burden of this disease. Two-dimensional monolayers of colorectal cancer cell lines represent the traditional in vitro models for disease and are often used for diverse purposes, including delineation of molecular pathways associated with disease aetiology or to gauge drug efficacy. The lack of complexity in such models, chiefly the limited epithelial cell diversity and differentiation, attenuated mucus production, lack of microbial interactions and mechanical stresses, has driven interest in development of more holistic and physiologically relevant in vitro model systems. In particular, established ex vivo patient-derived explant and patient-derived tumour xenograft models have been supplemented by progress in organoid and microfluidic organ-on-a-chip cultures. Here we discuss the applicability of advanced culturing technologies, such as organoid systems, as models for colorectal cancer and for testing chemotherapeutic drug sensitivity and efficacy. We highlight current challenges associated with organoid technologies and discuss their future for more accurate disease modelling and personalized medicine.