Abstract: Methods for testing the effects of therapeutic compound candidates on a phenotypic organoid model is provided. Such a method includes steps of generating the phenotypic organoid model on a high throughput screening platform, treating the organoid with a therapeutic compound candidate, and testing one or more effects resulting from treatment with each of the therapeutic compound candidates. The testing method that has led to identification of a method for treating or preventing cysts is provided. That method may include contacting a population of cells with an inotrope, wherein the inotrope prevents cyst formation, shrinks existing cysts, or both. That method may be used to treat cystogenic diseases or conditions such as Polycystic Kidney Disease (PKD).