Enzalutamide

The following antibodies (Abs) were used for immunoblotting (IB) analysis: mouse monoclonal Abs to PSMA (ab-19,071; Abcam), CD9 (sc-13,118; Santa Cruz Biotechnology), CD81 (ab-23,505; Abcam), CD63 (ab-8219; Abcam), GM130 (61,820; BD Biosciences), EpCAM (2929; Cell Signaling Technology), TUBULIN (T-8535; Sigma); rabbit mAb to TSG101 (ab-125,011; Abcam); rabbit polyclonal Abs (pAbs) to FLOTILLIN1 (FLOT1) (ab-41,927; Abcam), GFP (ab-6556; Abcam), CALNEXIN (CANX) (sc-11,397; Santa Cruz Biotechnology), ERK1 (sc-93; Santa Cruz Biotechnology), and Rb-IgG (Sigma). A goat pAb against human Trop-2 (AF650; R&D Biosystems) was used. A rabbit serum pAb against the cytoplasmic domain of human β3 [51 (link)] and a rabbit serum pAb against the cytoplasmic domain of human αv [14 (link)] were used. The GRGDSPK peptide (containing an RGD motif) and the GRGESP peptide (containing a RGE motif) were from Gibco Brl. Abiraterone acetate (Janssen Pharmaceuticals) and enzalutamide (Astellas Pharma) were used to treat prostate cancer patients.

In the phase Ib, taselisib (supplied by Genentech, Inc.) was administered orally at a starting dose of 2 mg and escalated to 4 mg, 6 mg and 8 mg in a 3+3 trial design. This was in combination with 160 mg enzalutamide (supplied by Astellas Pharma, US) taken daily orally without interruption for a 28-day cycle. Patients were treated until disease progression or unacceptable toxicity. In phase II, patients received either 160 mg enzalutamide alone or 160 mg enzalutamide in combination with 4 mg taselisib orally, as prior phase I single agent testing of taselisib showed activity at 4 mg(21 (link)).