Polycystic kidney disease, particularly the autosomal dominant form (ADPKD), is a genetic disorder characterized by the formation of cysts derived from the renal tubular epithelium. Approximately 50 % of patients require dialysis or kidney replacement therapy before the age of 60 due to the limited efficacy and significant side effects of tolvaptan, the only approved drug for this condition (1).
Current disease models, mainly bidimensional cell cultures and animals, have remarkable limitations and are mainly used in target-based drug discovery strategies, thereby producing a bias towards already known molecular targets and limiting identification of novel mechanisms. In recent years, 3D cell cultures such as organoids have emerged as promising tools for modelling ADPKD and enhancing drug discovery yet their complexity and persistent focus on target-based strategies limit their applicability (2). Therefore, developing three-dimensional models with a phenotypic approach focused on cellular response is essential and may allow the identification of new treatments.
The objective of this study was to develop a miniaturized phenotypic assay using immortalized MDCK (Madin-Darby Canine Kidney) cells, with potential applicability in high-throughput screening (HTS). To this end, we optimized culture conditions in a collagen matrix, as well as the cyst formation resulting from treatment with forskolin. Finally, we tested the effect of rapamycin and birinapant in forskolin-induced cysts.
Initially, we observed that forskolin induced cyst formation at 5 and 10 µM compared to the DMSO control (both p<0,0001). Subsequently, we recorded that treatment with rapamycin at 0,05 µM reduced the number of cysts compared with forskolin 5 µM (p<0,0001) and 10 µM (p<0,01). Moreover, it was found a similar effect in presence of birinapant at 1 µM in comparison with forskolin 5 µM (p<0,0001) and 10 µM (p<0,05). In conclusion, we have successfully developed a miniaturized 3D phenotypic ADPKD model in 384-well plates, with potential applicability for HTS-based drug discovery in this disease.
