Fig 1.
Differential KRT expression in fractionated prostate epithelial cells.
(A). Differential expression of the basal KRT5, luminal KRT 8 and KRT 13 among the four cell populations analyzed (FC-red dot, LC-blue dots, BC-green dots, and TIC-purple dots) from the Affymetrix Gene Chip Human U133 PLUS 2.0 Array analysis. Each dot represents an individual sample, with the exception of the FC, where 6 samples were pooled to generate sufficient RNA for analysis. (B) RNA was isolated from sorted cell fractions generated from 3 unique prostate tissue specimens and evaluated via Quantitative RT-PCR. Unfractionated total prostate cell control is represented by the black column, Epcam+CD44+CD49fHi basal cells (BC) represented by green column, Epcam+CD44-CD49fhi tubule initiating cells (TIC) represented by purple column, and Epcam+CD44-CD49fLo luminal cells (LC) represented by blue column. TIC had significantly higher expression than BC (p<0.05). (C) KRT13 immunostaining of cytospin slides of sorted cell fractions (BC, TIC, and LC) demonstrates relative abundance of KRT13+ cells, designated by brown staining, within the TIC fraction relative to BC and LC. The bar graph demonstrates the average cell count of KRT13+ cells per/cytospin slide (average of 3–5 slides, P<0.05).
Fig 2.
IHC analysis of KRT13 expression in fetal and adult prostate tissue and recombinant grafts.
(A) Immunohistochemical (IHC) analysis of fetal prostate tissue, benign adult prostate tissue, and HGPIN lesion. Representative images of fetal tissue 14–18 weeks gestation are shown. KRT13+ Benign and HGPIN lesions were routinely observed in radical prostatectomy specimens. (B) Schematic of in vivo prostate recombination assay. All grafts were generated from freshly dissociated prostate cells combined with hFPS and injected subcutaneously with Matrigel™ in vivo. (C) IHC analysis of recombinant grafts stained for KRT13. 8-week graft demonstrates predominantly cord-like structures, and 24-week grafts demonstrate differentiated tubules with lumens. Grafts generated from 3 individual prostate specimens were collected at each time period (<12 weeks and >24 weeks). Representative images of KRT13 expression are shown.
Fig 3.
KRT13 expression in prostate cancer.
(A) KRT13 expression is detected (from right to left) in a cancer core from the WLA TMA, a diagnostic PNBX core from a patient with diffuse bone metastases, a biopsy of a bone metastatic site, and residual prostate glands in a prostate specimen from a patient treated with radiation and ADT. (B) Bar graph representing the relative abundance of KRT13+ tumor foci identified in localized (stage M0) and metastatic (stage M1) cases. KRT13+ foci are identified in approximately 9% of prostate cancer cores from M0 cases in the WLA TMA. In contrast, all diagnostic PNBX from patients with diffuse bone metastases display KRT13+ tumor foci.
Table 1.
Kaplan-Meier Estimated Probabilities for Survival.
Fig 4.
KRT13 expression in localized cancer is significantly associated with shorter time to recurrence.
Kaplan Meier curves generated from outcomes of cases compiled in the WLA TMA and stratified based on the presence of KRT13+ tumor foci. A. Time to recurrence (P = 0.031). B. Time to CRPC (P = 0.331). C. Time to metastases (p = 0.032). D. Overall survival (p = 0.004).