Patient-derived prostate cancer organoids require α6-integrins for self-renewal and recapitulate genetic heterogeneity and histopathology of the original tumors

Abstract Background: Modeling the pathophysiology of prostate cancer (PCa) remains a challenge and primary tissue-derived organoid cultures have emerged as promising models representing good tissue mimicry. Methods: We have established 36 PCa patient-derived organoid cultures that self-renew and can be maintained long-term. Using CRISPR-mediated genomic editing, selected PCa organoids were also genetically engineered to modulate their tumorigenic and self-renewal properties. We show that PCa organoids can also be readily utilized in drug sensitivity tests. In vivo, orthotopic xenograft studies were performed to recapitulate the original tumor phenotype. Finally, we performed scRNA and bulk RNA sequencing to show the multi-cellular involvement in PCa organoid self-renewal and tumorigenesis. Results: The morphological properties of cancer organoids were found to correlate with the disease grading. Importantly, detailed analyses of selected organoid lines indicated that they maintain the heterogeneity, gene expression profile, and histological architecture of their primary tumor-of-origin and recapitulate these features in vivo as xenografts. Finally, we show that α6-integrin expression is a requisite for the growth and long-term propagation of human PCa organoids while α2-integrin expression is dispensable. High expression levels of both α6- and α2-integrins have been documented in putative prostate epithelial stem cells which likely play an important role in PCa tumorigenesis. Our single-cell analysis identified a distinct cell population with a stem cell profile and high expression of α6- and α2-integrins. Discussion: Our data suggest that α6-integrin expression promotes PCa stem cell self-renewal and demonstrates the versatile biomedical utilities of PCa-derived organoid models.