Research Article

Identification of Genes Required for Enzalutamide Resistance in Castration-Resistant Prostate Cancer Cells In Vitro

Published: 2021-2-1

Journal: Molecular Cancer Therapeutics

DOI: 10.1158/1535-7163.mct-20-0244

Abstract

Castration-resistant prostate cancer can be treated with the antiandrogen enzalutamide, but responses and duration of response are variable. To identify genes that support enzalutamide resistance, we performed a short hairpin RNA (shRNA) screen in the bone-homing, castration-resistant prostate cancer cell line, C4-2B. We identified 11 genes (TFAP2C, CAD, SPDEF, EIF6, GABRG2, CDC37, PSMD12, COL5A2, AR, MAP3K11, and ACAT1) whose loss resulted in decreased cell survival in response to enzalutamide. To validate our screen, we performed transient knockdowns in C4-2B and 22Rv1 cells and evaluated cell survival in response to enzalutamide. Through these studies, we validated three genes (ACAT1, MAP3K11, and PSMD12) as supporters of enzalutamide resistance in vitro. Although ACAT1 expression is lower in metastatic castration-resistant prostate cancer samples versus primary prostate cancer samples, knockdown of ACAT1 was sufficient to reduce cell survival in C4-2B and 22Rv1 cells. MAP3K11 expression increases with Gleason grade, and the highest expression is observed in metastatic castration-resistant disease. Knockdown of MAP3K11 reduced cell survival, and pharmacologic inhibition of MAP3K11 with CEP-1347 in combination with enzalutamide resulted in a dramatic increase in cell death. This was associated with decreased phosphorylation of AR-Serine650, which is required for maximal AR activation. Finally, although PSMD12 expression did not change during disease progression, knockdown of PSMD12 resulted in decreased AR and AR splice variant expression, likely contributing to the C4-2B and 22Rv1 decrease in cell survival. Our study has therefore identified at least three new supporters of enzalutamide resistance in castration-resistant prostate cancer cells in vitro.

Faculty Members

  • Robert J. Matusik - 5Department of Urology, Vanderbilt University Medical Center, Nashville, Tennessee.
  • Robert A. Phillips - 4Biological Sciences, Salisbury University, Salisbury, Maryland.
  • Sarah E. Kohrt - 1Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio.2Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio.
  • Jagpreet S. Nanda - 2Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio.3Department of Urology, Case Western Reserve University, Cleveland, Ohio.
  • Magdalena M. Grabowska - 1Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio.2Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio.3Department of Urology, Case Western Reserve University, Cleveland, Ohio.9Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio.
  • Philip D. Anderson - 4Biological Sciences, Salisbury University, Salisbury, Maryland.
  • Yajun Yi - 8Quality, Safety and Risk Prevention, Vanderbilt University Medical Center, Nashville, Tennessee.
  • Renjie Jin - 5Department of Urology, Vanderbilt University Medical Center, Nashville, Tennessee.
  • Xiuping Yu - 6Department of Biochemistry, Louisiana State University Health Shreveport, Shreveport, Louisiana.
  • Wisam N. Awadallah - 2Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio.3Department of Urology, Case Western Reserve University, Cleveland, Ohio.
  • Peter E. Clark - 7Department of Urology, Levine Cancer Center/Atrium Health, Charlotte, North Carolina.
  • Thomas C. Case - 5Department of Urology, Vanderbilt University Medical Center, Nashville, Tennessee.

Themes

  • Castration-resistant prostate cancer
  • Androgen receptor regulation
  • Cell survival mechanisms
  • Genetic factors in cancer
  • Enzalutamide resistance

Categories

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