In:
Clinical Cancer Research, American Association for Cancer Research (AACR), Vol. 22, No. 17 ( 2016-09-01), p. 4505-4516
Abstract:
Purpose: We have shown that the phenotypically undifferentiated (PSA−/lo) prostate cancer cell population harbors long-term self-renewing cancer stem cells (CSC) that resist castration, and a subset of the cells within the PSA−/lo population bearing the ALDHhiCD44+α2β1+ phenotype (Triple Marker+/TM+) is capable of robustly initiating xenograft tumors in castrated mice. The goal of the current project is to further characterize the biologic properties of TM+ prostate cancer cell population, particularly in the context of initiating and propagating castration-resistant prostate cancer (CRPC). Experimental Design: The in vivo CSC activities were measured by limiting-dilution serial tumor transplantation assays in both androgen-dependent and androgen-independent prostate cancer xenograft models. In vitro clonal, clonogenic, and sphere-formation assays were conducted in cells purified from xenograft and patient tumors. qPCR, Western blot, lentiviral-mediated gene knockdown, and human microRNA arrays were performed for mechanistic studies. Results: By focusing on the LAPC9 model, we show that the TM+ cells are CSCs with both tumor-initiating and tumor-propagating abilities for CRPC. Moreover, primary patient samples have TM+ cells, which possess CSC activities in “castrated” culture conditions. Mechanistically, we find that (i) the phenotypic markers are causally involved in CRPC development; (ii) the TM+ cells preferentially express castration resistance and stem cell–associated molecules that regulate their CSC characteristics; and (iii) the TM+ cells possess distinct microRNA expression profiles and miR-499-5p functions as an oncomir. Conclusions: Our results define the TM+ prostate cancer cells as a population of preexistent stem-like cancer cells that can both mediate and propagate CRPC and highlight the TM+ cell population as a therapeutic target. Clin Cancer Res; 22(17); 4505–16. ©2016 AACR.
Type of Medium:
Online Resource
ISSN:
1078-0432
,
1557-3265
DOI:
10.1158/1078-0432.CCR-15-2956
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2016
detail.hit.zdb_id:
1225457-5
detail.hit.zdb_id:
2036787-9
