Subcutaneous prostate cancer xenograft model

PSMA-positive (22Rv1) and negative (PC3) human prostate carcinoma cell lines were purchased from American Type Culture Collection (Rockville, MD, USA). Both cell lines were maintained in RPMI 1640 medium containing 10% fetal bovine serum prior to use.

In total, nine subcutaneous prostate cancer xenograft model mice were generated in-house. Six of the mice had 22Rv1 tumors, which were induced by inoculating 22Rv1 PSMA-positive cells (1.0 × 10⁷ cells in 100 μL phosphate-buffered saline) into the right flank of each mouse. The other three model mice bearing both 22Rv1 and PC3 tumors, which were established by inoculating 22Rv1 PSMA-positive cells (1.0 × 10⁷ cells) into the right femoral of the mice and PC3 PSMA-negative cells (1.0 × 10⁷ cells) into the left femoral of the mice. All the mice were maintained under the abovementioned conditions for approximately two weeks until the tumors reach a size of approximately 3 mm in diameter (measured with calipers). Three 22Rv1 tumor-bearing mice were used in the PET/CT studies to characterize the biodistribution and pharmacokinetics, while the other three 22Rv1 tumor-bearing mice underwent PET/CT studies to investigate the specificity of [⁶⁸Ga]PSMA-11. The three model mice bearing both 22Rv1 and PC3 tumors underwent PET/CT studies to investigate the selectivity of [⁶⁸Ga]PSMA-11.