Fig. 5. Studying PCa cell heterogeneity in PCa cell and xenograft models: PSA^−/lo PCa cells accumulate in experimental CRPC models.

A–B. Accumulation of PSA^−/lo cells in LNCaP-AI tumors. (A) Double immunofluorescence (IF) staining of AR and PSA in AD (androgen-dependent) vs. AI (androgen-independent) LNCaP xenograft tumors. In panel c, the white line demarcates 3 AR⁺PSA⁺ cells and the arrows point to 2 AR⁺PSA^−/lo cells. In panel d, the white circle demarcates several AR-PSA^−/lo cells and the arrows point to 3 AR-PSA⁺ cells. In panel h, the arrows illustrate several AR-PSA^−/lo cells. Shown are representative confocal images (original magnification; x400). (B) Quantification of the 4 subtypes of PCa cells in AD and AI LNCaP xenograft tumors. A total of 809 and 907 cells were counted from several AD and AI tumors, respectively. *P < 0.001 in AI compared in AD tumors.

C. WB analysis of AR and PSA heterogeneity in cultured LNCaP cell sublines. PC3 and IGR1 cells, which are negative for both proteins, were used as controls. Note that the wild-type LNCaP cells (lane 3) were AR⁺PSA⁺ whereas LNCaP-abl cells AR⁺PSA⁻ (lane 2). LNCaP-CDSS and LNCaP-MDV cells were both AR⁻PSA⁻ (lanes 5–6). The arrow indicates the ~114 kD full-length AR and lower bands represent AR splice variants (top panel).

D. Heterogeneity in expression of phenotypic markers in cultured LNCaP cells. Shown are representative IF images of AR, PSA, pan-cytokeratin, EpCAM and PSMA.

E. Double IF staining of AR and PSA in AD vs. AI LAPC4 xenograft tumors. In panel c, the white circle indicates several AR⁺PSA^−/lo cells and arrows indicate AR-PSA⁺ cells. In panel d, arrows point to AR-PSA^−/lo cells. Note significantly increased PSA^−/lo LAPC4 cells in the AI tumor (f). Shown are representative confocal images (original magnification; x400).

All panels (except most of D) were adapted with permission from reference [144].