ON-TARGETplus siRNA pools for gene expression knockdown.

List of the 44 3D structures of HSC70 (HSPA8) in complex with the BAG domain of BAG-1 used in comparative structural analyses.

Antibodies used for western blot analyses.

Development and characterization of BAG-1 knockout mice.

Synthego BAG-1 sgRNA for BAG-1 CRISPR knockout clones.

Development of castration resistant prostate cancer patient derived xenograft organoids.

Thio-2 reduces genome-wide androgen receptor binding in LNCaP prostate cancer cells.

Mouse organ hematoxylin and eosin, and BAG-1 immunohistochemistry, in BAG-1 knockout mice.

New androgen receptor (AR) pathway inhibitors (ARPIs) in clinical development, including AR degraders and CYP11A inhibitors, largely target ligand-dependent AR activation and have reported antitumor activity in metastatic castration-resistant prostate cancer (mCRPC) resistant to established ARPIs, predominately against tumors with AR mutations. We hypothesized that AR-mutated mCRPC exhibits lower AR splice variant 7 (AR-V7) expression and remains full-length-AR (FL-AR) driven, explaining, in part, the antitumor activity of these AR ligand-binding domain (LBD) targeting drugs. The data herein demonstrate that mCRPC tissue biopsies with detectable AR mutations express significantly lower levels of AR-V7 protein and associate with better overall survival and enhanced sensitivity to ARPIs. This is independent of differences in the total number of global splicing events but may be related to differences in splicing factor expression between AR-mutated and nonmutated mCRPC. In conclusion, AR-mutated mCRPC frequently exhibits low AR-V7 expression, arguably explaining the enhanced sensitivity to ARPIs observed in these cancers. Consequently, AR mutation status may serve as a biomarker to predict response to AR-directed therapies.

Mouse organ hematoxylin and eosin, and BAG-1 immunohistochemistry, in BAG-1 knockout mice.

TaqMan probes for qRT-PCR analyses.

Thio-2 downregulates C-MYC expression through a BAG-1 independent mechanism.

BAG-1 knockout female mice are fertile and viable with reduced gestation.

Treatment with Thio-2 inhibits transactivation of the unstimulated and stimulated androgen receptor and the constitutively active androgen receptor splice variant-7.

Thio-2, may bind the N-terminus of the androgen receptor through a similar binding mode to EPI-001.

Description of Materials and Methods not contained within the main Materials and Methods section

Protocols and antibodies for immunohistochemical analyses.

In-vivo treatment of patient derived model of lethal prostate cancer demonstrates Thio-2 to be well tolerated with associated impact on AR signaling and growth.