Androgen Deprivation Therapy Potentiates the Efficacy of Vascular Targeted Photodynamic Therapy of Prostate Cancer Xenografts

WST11 vascular targeted photodynamic therapy (VTP) is a local ablation approach relying upon rapid, free radical-mediated destruction of tumor vasculature. A phase III trial showed that VTP significantly reduced disease progression when compared to active surveillance in patients with low-risk prostate cancer (PCa). The aim of this study was to identify a druggable pathway that could be combined with VTP to improve its efficacy and applicability to higher risk PCa tumors. LNCaP-AR cells were grafted into intact mice to establish tumors. The mice were then treated with WST11 at 9 mg/kg, and tumors were focally treated with VTP using 100 mW laser fluence. Tumors were collected at 3, 6, or 24 hr, 1 week and 8.5 weeks post VTP. Mice with control tumors received WST11, but were not exposed to the laser and were matched to the 1 and 8.5 week treatment groups. RNA was isolated from 36 total tumors for microarray hybridization, with 4-8 replicates per group. 32 samples were used for analysis (n=4 from 24 hr VTP removed during quality control).