title: Longitudinal tracking of subpopulation dynamics and molecular changes during LNCaP cell castration and identification of inhibitors that could target the PSA-/lo castration-resistant cells.
abstract: We have recently demonstrated that the undifferentiated PSA-/lo prostate cancer (PCa) cell population harbors self-renewing long-term tumor-propagating cells that are refractory to castration, thus representing a therapeutic target. Our goals here are, by using the same lineage-tracing reporter system, to track the dynamic changes of PSA-/lo and PSA+ cells upon castration in vitro, investigate the molecular changes accompanying persistent castration, and develop large numbers of PSA-/lo PCa cells for drug screening. To these ends, we treated LNCaP cells infected with the PSAP-GFP reporter with three regimens of castration, i.e., CDSS, CDSS plus bicalutamide, and MDV3100 continuously for up to ~21 months. We observed that in the first ~7 months, castration led to time-dependent increases in PSA-/lo cells, loss of AR and PSA expression, increased expression of cancer stem cell markers, and many other molecular changes. Meanwhile, castrated LNCaP cells became resistant to high concentrations of MDV3100, chemotherapeutic drugs, and other agents. However, targeted and medium-throughput library screening identified several kinase (e.g., IGF-1R, AKT, PI3K/mTOR, Syk, GSK3) inhibitors as well as the BCL2 inhibitor that could effectively sensitize the LNCaP-CRPC cells to killing. Of interest, LNCaP cells castrated for >7 months showed evidence of cyclic changes in AR and the mTOR/AKT signaling pathways potentially involving epigenetic mechanisms. These observations indicate that castration elicits numerous molecular changes and leads to enrichment of PSA-/lo PCa cells. The ability to generate large numbers of PSA-/lo PCa cells should allow future high-throughput screening to identify novel therapeutics that specifically target this population.
authors.affiliation: Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA.
authors.forename: Kiera
authors.initials: K
authors.lastname: Rycaj
authors.affiliation: College of Pharmacy, Targeted Therapeutic Drug Discovery and Development Core Facility (TTDDD), The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Eun Jeong
authors.initials: EJ
authors.lastname: Cho
authors.affiliation: Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA.
authors.forename: Hsueh-Ping
authors.initials: HP
authors.lastname: Chao
authors.affiliation: Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA.
authors.forename: Bigang
authors.initials: B
authors.lastname: Liu
authors.affiliation: Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA.
authors.forename: Qiuhui
authors.initials: Q
authors.lastname: Li
authors.affiliation: College of Pharmacy, Targeted Therapeutic Drug Discovery and Development Core Facility (TTDDD), The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Ashwini K
authors.initials: AK
authors.lastname: Devkota
authors.affiliation: Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA.
authors.forename: Dingxiao
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA.
authors.forename: John
authors.initials: J
authors.lastname: Moore
authors.affiliation: College of Pharmacy, Targeted Therapeutic Drug Discovery and Development Core Facility (TTDDD), The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Kevin N
authors.initials: KN
authors.lastname: Dalby
authors.affiliation: Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA.|Cancer Stem Cell Institute, Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.|Centers for Cancer Epigenetics, Stem Cell and Developmental Biology, RNA Interference and Non-coding RNAs, and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Dean G
authors.initials: DG
authors.lastname: Tang
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D064129:Prostatic Neoplasms, Castration-Resistant / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D047428:Protein Kinase Inhibitors; D017430:Prostate-Specific Antigen
keywords: cancer stem cells; castration resistance; cellular heterogeneity; differentiation; prostate cancer