Translocator protein blockade reduces prostate tumor growth

Arlee Fafalios, Ardavan Akhavan, Anil V. Parwani, Robert Bies, Kevin J. McHugh, Beth Pflug

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Purpose: The transmembrane molecule, translocator protein (TSPO), has been implicated in the progression of epithelial tumors. TSPO gene expression is high in tissues involved in steroid biosynthesis, neurodegenerative disease, and in cancer, and overexpression has been shown to contribute to pathologic conditions including cancer progression in several different models. The goal of our study was to examine the expression and biological relevance of TSPO in prostate cancer and show that the commonly prescribed benzodiazepine lorazepam, a ligand for TSPO, exhibits anticancer properties. Experimental Design: Immunohistochemical analysis using tissue microarrays was used to determine the expression profile of TSPO in human prostate cancer tissues. To show the effect of TSPO ligands (lorazepam and PK11195) in prostate cancer, we used cell proliferation assays, apoptosis ELISA, prostate cancer xenograft study, and immunohistochemistry. Results: TSPO expression is increased in prostatic intraepithelial neoplasia, primary prostate cancer, and metastases compared with normal prostate tissue and benign prostatichyperplasia. Furthermore, TSPO expression correlates with disease progression, as TSPO levels increased with increasing Gleason sum and stage with prostate cancer metastases demonstrating the highest level of expression among all tissues examined. Functionally, we have shown that lorazepam has antiproliferative and proapoptoticpro perties in vitro and in vivo. Additionally, we have shown that TSPO overexpression in nontumorigenic cells conferred susceptibility to lorazepam-induced growth inhibition. Conclusion: These data suggest that blocking TSPO function in tumor cells induces cell death and denotes a survival role for TSPO in prostate cancer and provides the first evidence for the use of benzodiazepines in prostate cancer therapeutics.

Original languageEnglish
Pages (from-to)6177-6184
Number of pages8
JournalClinical Cancer Research
Volume15
Issue number19
DOIs
StatePublished - Oct 1 2009

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Prostate
Prostatic Neoplasms
Growth
Lorazepam
Neoplasms
Proteins
Benzodiazepines
Tissue Array Analysis
Prostatic Intraepithelial Neoplasia
Neoplasm Metastasis
Ligands
Heterografts
Neurodegenerative Diseases
Disease Progression
Cell Death
Research Design
Enzyme-Linked Immunosorbent Assay
Immunohistochemistry
Steroids
Cell Proliferation

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

Translocator protein blockade reduces prostate tumor growth. / Fafalios, Arlee; Akhavan, Ardavan; Parwani, Anil V.; Bies, Robert; McHugh, Kevin J.; Pflug, Beth.

In: Clinical Cancer Research, Vol. 15, No. 19, 01.10.2009, p. 6177-6184.

Research output: Contribution to journalArticle

Fafalios, Arlee ; Akhavan, Ardavan ; Parwani, Anil V. ; Bies, Robert ; McHugh, Kevin J. ; Pflug, Beth. / Translocator protein blockade reduces prostate tumor growth. In: Clinical Cancer Research. 2009 ; Vol. 15, No. 19. pp. 6177-6184.
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