An unbiased seed-based RNAi selection screen identifies small RNAs that inhibit androgen signaling and prostate cancer cell growth

Joshua M Corbin; Constantin Georgescu; Lin Wang; Jonathan D Wren; Magdalena Bieniasz; Chao Xu; Adam S Asch; Maria J Ruiz Echevarría

doi:10.1016/j.omtn.2023.06.021

An unbiased seed-based RNAi selection screen identifies small RNAs that inhibit androgen signaling and prostate cancer cell growth

Mol Ther Nucleic Acids. 2023 Jun 28:33:257-272. doi: 10.1016/j.omtn.2023.06.021. eCollection 2023 Sep 12.

Authors

Joshua M Corbin^{1

2}, Constantin Georgescu³, Lin Wang⁴, Jonathan D Wren³, Magdalena Bieniasz⁴, Chao Xu^{1

5}, Adam S Asch^{1

6}, Maria J Ruiz Echevarría^{1

2

6}

Affiliations

¹ Stephenson Cancer Center, 800 NE 10th Street, Oklahoma City, OK 73104, USA.
² Department of Pathology, Biomedical Sciences Building, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK 73104, USA.
³ Genes and Human Disease Research Program, Division of Genomics and Data Sciences, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK 73104, USA.
⁴ Aging and Metabolism Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK 73104, USA.
⁵ Department of Biostatistics and Epidemiology, Hudson College of Public Health, University of Oklahoma Health Sciences Center, 801 N.E. 13 Street, Oklahoma City, OK 73104, USA.
⁶ Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.

Abstract

Blocking androgen receptor signaling is the mainstay of therapy for advanced prostate cancer (PCa). However, acquired resistance to single agents targeting this pathway results in the development of lethal castration-resistant PCa. Combination therapy approaches represent a promising strategy for the treatment of advanced disease. Here, we explore a therapeutic strategy for PCa based on the ability of shRNAs/siRNAs to function essentially as miRNAs and, via seed sequence complementarity, induce RNA interference of numerous targets simultaneously. We developed a library that contained shRNAs with all possible seed sequence combinations to identify those ones that most potently reduce cell growth and viability when expressed in PCa cells. Validation of some of these RNAi sequences indicated that the toxic effect is associated with seed sequence complementarity to the 3' UTR of AR coregulatory and essential genes. In fact, expression of siRNAs containing the identified toxic seed sequences led to global inhibition of AR-mediated gene expression and reduced expression of cell-cycle genes. When tested in mice, the toxic shRNAs also inhibited castration-resistant PCa and exhibited therapeutic efficacy in pre-established tumors. Our findings highlight RNAi of androgen signaling networks as a promising therapeutic strategy for PCa.

Keywords: MT: Oligonucleotides: Therapies and Applications; RNA interference; androgen receptor coregulators; androgen signaling; gene networks; prostate cancer; prostate cancer essential genes; seed sequence; small RNA.

Abstract

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