In Vivo Genome-Wide CRISPR Screening Identifies CITED2 as a Driver of  Prostate Cancer Bone metastasis
Most cancer deaths are due to metastatic dissemination to distant organs. Bone is the most frequently affected organ in metastatic prostate cancer and a major cause of prostate cancer deaths. Yet, our partial understanding of the molecular factors that drive bone metastasis has been a limiting factor for developing preventative and therapeutic strategies to improve patient survival and well-being. Although recent studies have uncovered molecular alterations that occur in prostate cancer metastasis, their functional relevance for bone metastasis is not well understood. Using genome-wide CRISPR activation and inhibition screens we have identified multiple drivers and suppressors of prostate cancer metastasis. Through functional validation, including innovative organ-on-a-chip invasion platform for studying bone tropism, our study identifies the transcriptional modulator, CITED2, as a novel driver of prostate cancer bone metastasis and uncovers multiple new potential molecular targets for bone metastatic disease. Overall design: A CRISPRa screen was performed in non-metastatic human prostate cancer cells to identify drivers of metastasis. This identified CITED2 as a main target CITED2 was then overexpressed using CRISPRa in isogenic 22Rv1 cells and using cDNA overexpression in LNCaP cells. RNAseq was performed from control and CITED2 overexpressed cell lines, in duplicate for 22Rv1 and triplicate for LNCaP