Comprehensive evaluation of the role of EZH2 in the growth, invasion, and aggression of a panel of prostate cancer cell lines.
BACKGROUND
Although most prostate cancers respond well to initial treatments, a fraction of prostate cancers are more aggressive and will recur and metastasize. At that point, there are few treatment options available. Significant efforts have been made to identify biomarkers that will identify these more aggressive cancers to tailor a more vigorous treatment in order to improve outcome. Polycomb Group protein enhancer of zeste 2 (EZH2) was found to be overexpressed in metastatic prostate tumors, and is considered an excellent candidate for such a biomarker. Scattered studies have found that EZH2 overexpression causes neoplastic transformation, invasion, and growth of prostate cells. However, these studies utilized different systems and cell lines, and so are difficult to correlate with one another.


METHODS
In this study, a comprehensive evaluation of the phenotypic effects of EZH2 in a panel of five prostate cancer cell lines was performed. By using multiple cell lines, and examining overexpression and knockdown of EZH2 concurrently, a broad view of EZH2's role in prostate cancer was achieved.


RESULTS
Overexpression of EZH2 led to more aggressive behaviors in all prostate cell lines tested. In contrast, downregulation of EZH2 reduced invasion and tumorigenicity of androgen-independent (AI) cell lines CWR22Rv1, PC3, and DU145, but not of androgen-dependent (AD) cell lines LAPC4 and LNCaP.


CONCLUSIONS
Findings from this study suggest that AI prostate tumors are more dependent on EZH2 expression than AD tumors. Our observations provide an explanation for the strong correlation between EZH2 overexpression and advanced stage, aggressive prostate cancers.
Karanikolas
Breanne D W
BD
Department of Molecular and Medical Pharmacology, Institute of Molecular Medicine, University of California Los Angeles, Los Angeles, California 90095-1738, USA.
Figueiredo
Marxa L
ML
Wu
Lily
L
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology*; D000728:Androgens / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D000071221:Enhancer of Zeste Homolog 2 Protein; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D016086:Lentivirus / Q000235:genetics; D008297:Male; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D010641:Phenotype; D063151:Polycomb Repressive Complex 2; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D000728:Androgens; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D014157:Transcription Factors; C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein; D063151:Polycomb Repressive Complex 2