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Introduction: MRI-targeted biopsy (TB) increases overall prostate-cancer (PCa) detection-rates and decreases the risk of insignificant PCa detection. However, the impact of these findings on the definite pathology after radical prostatectomy (RP) is under debate.
Materials and Methods: Between 01/2014 and 12/2018, 366 patients undergoing prostate biopsy and RP were retrospectively analyzed. The correlation between biopsy Gleason-score (highest Gleason-score in a core) and the RP Gleason-score in patients undergoing systematic biopsy (SB-group) (n = 221) or TB+SB (TB-group, n = 145) was tested using the ISUP Gleason-group grading (GGG, scale 1–5). Sub analyses focused on biopsy GGG 1 and GGG ≥ 2.
Results: Proportions of biopsy GGG 1–5 in the SB-group and TB-group were 24.4, 37.6, 19, 10.9, 8.1% and 13.8, 43.4, 24.2, 13.8, 4.8%, respectively (p = 0.07). Biopsy and pathologic GGG were concordant in 108 of 221 (48.9%) in SB- and 74 of 145 (51.1%) in TB-group (p = 0.8). Gleason upgrading was recorded in 33.5 and 31.7% in SB- vs. TB-group (p = 0.8). Patients with biopsy GGG 1 undergoing RP showed an upgrading in 68.5%(37/54) in SB- and 75%(15/20) in TB-group (p = 0.8). In patients with biopsy GGG ≥ 2 concordance increased for both biopsy approaches (54.5 vs. 55.2% for SB- vs. TB-group, p = 0.9).
Discussion: Irrespective of differences in PCa detection-rates between TB- and SB-groups, no significant differences in GGG concordance and upgrading between patients of both groups undergoing biopsy, followed by RP, were recorded. Concordance rates increased in men with biopsy GGG ≥ 2. TB seems to detect more patients with PCa without a difference in concordance with final pathology.
The mechanistic target of rapamycin (mTOR) is elevated in prostate cancer, making this protein attractive for tumor treatment. Unfortunately, resistance towards mTOR inhibitors develops and the tumor becomes reactivated. We determined whether epigenetic modulation by the histone deacetylase (HDAC) inhibitor, valproic acid (VPA), may counteract non-responsiveness to the mTOR inhibitor, temsirolimus, in prostate cancer (PCa) cells. Prostate cancer cells, sensitive (parental) and resistant to temsirolimus, were exposed to VPA, and tumor cell growth behavior compared. Temsirolimus resistance enhanced the number of tumor cells in the G2/M-phase, correlating with elevated cell proliferation and clonal growth. The cell cycling proteins cdk1 and cyclin B, along with Akt-mTOR signaling increased, whereas p19, p21 and p27 decreased, compared to the parental cells. VPA significantly reduced cell growth and up-regulated the acetylated histones H3 and H4. Cdk1 and cyclin B decreased, as did phosphorylated mTOR and the mTOR sub-complex Raptor. The mTOR sub-member Rictor and phosphorylated Akt increased under VPA. Knockdown of cdk1, cyclin B, or Raptor led to significant cell growth reduction. HDAC inhibition through VPA counteracts temsirolimus resistance, probably by down-regulating cdk1, cyclin B and Raptor. Enhanced Rictor and Akt, however, may represent an undesired feedback loop, which should be considered when designing future therapeutic regimens.