PCA3 noncoding RNA is involved in the control of prostate-cancer cell survival and modulates androgen receptor signaling

Abstract

BackgroundPCA3 is a non-coding RNA (ncRNA) that is highly expressed in prostate cancer (PCa) cells, but its functional role is unknown. To investigate its putative function in PCa biology, we used gene expression knockdown by small interference RNA, and also analyzed its involvement in androgen receptor (AR) signaling.MethodsLNCaP and PC3 cells were used as in vitro models for these functional assays, and three different siRNA sequences were specifically designed to target PCA3 exon 4. Transfected cells were analyzed by real-time qRT-PCR and cell growth, viability, and apoptosis assays. Associations between PCA3 and the androgen-receptor (AR) signaling pathway were investigated by treating LNCaP cells with 100 nM dihydrotestosterone (DHT) and with its antagonist (flutamide), and analyzing the expression of some AR-modulated genes (TMPRSS2, NDRG1, GREB1, PSA, AR, FGF8, CdK1, CdK2 and PMEPA1). PCA3 expression levels were investigated in different cell compartments by using differential centrifugation and qRT-PCR.ResultsLNCaP siPCA3-transfected cells significantly inhibited cell growth and viability, and increased the proportion of cells in the sub G0/G1 phase of the cell cycle and the percentage of pyknotic nuclei, compared to those transfected with scramble siRNA (siSCr)-transfected cells. DHT-treated LNCaP cells induced a significant upregulation of PCA3 expression, which was reversed by flutamide. In siPCA3/LNCaP-transfected cells, the expression of AR target genes was downregulated compared to siSCr-transfected cells. The siPCA3 transfection also counteracted DHT stimulatory effects on the AR signaling cascade, significantly downregulating expression of the AR target gene. Analysis of PCA3 expression in different cell compartments provided evidence that the main functional roles of PCA3 occur in the nuclei and microsomal cell fractions.ConclusionsOur findings suggest that the ncRNA PCA3 is involved in the control of PCa cell survival, in part through modulating AR signaling, which may raise new possibilities of using PCA3 knockdown as an additional therapeutic strategy for PCa control.

PRUNE2 is a human prostate cancer suppressor regulated by the intronic long noncoding RNA PCA3

“…Androgen stimulation of LNCaP cells with a synthetic testosterone homolog (R1881) induced a concomitant increase of PCA3 and decrease of PRUNE2 levels ( Fig. 3 F-H), consistent with a report that PCA3 modulates prostate cancer through AR signaling (15). We also observed an increase in nuclear localization of PRUNE2 and PCA3 along with androgen-induced responses (Fig.…”

Rôle des longs ARN non codants dans le développement normal et pathologique

“…Son utilisation comme marqueur pronostique dans le cancer du poumon a d'ailleurs été suggérée [4]. De même, des fonctions oncogéniques ont été suggérées pour plusieurs autres lncRNA dans, entre autres, le cancer du foie (HULC, highly up-regulated in liver cancer) [27], de la prostate (PCA3, prostate cancer antigen 3) [28,29] et du rein (MVIH, microvascular invasion in HCC) [30]. Finalement, certains lncRNA, tels que LincRNA-p21 et Meg3 (maternally expressed 3), ont été impliqués dans la modulation de la réponse p53 [31,32].…”

Prostate cancer: the need for biomarkers and new therapeutic targets

“…The highest preoperative serum levels correspond to metastatic PCa cases Serum Diagnosis, prognosis Zhao et al, 2010; Golgi membrane protein 1 (GOLM1) Type II Golgi transmembrane protein that collaborates in protein synthesis and transport of protein cargo Up-regulation of GOLM1 expression in PCa compared with normal prostate and BPH tissues Tissue, urine Diagnosis Varambally et al, 2008;Li et al, 2012 To be continued Bussemakers et al, 1999;Crawford et al, 2012;Ferreira et al, 2012;Yutkin et al, 2012 Phospho-choline- Prostate-specific antigen (PSA)-derived markers Include PSA density, PSA velocity, pro-PSA, and PSA doubling time Patients with PCa present increased PSA density, higher PSA velocity, lower PSA doubling time, and higher levels of pro-PSA Serum Predictive, prognosis Makarov et al, 2009 Phosphatase and tensin homolog (PTEN) Tumor suppressor gene that encodes the phosphatase responsible for the conversion of PIP3 to inactive phosphatidylinositol (4,5) biphosphate PTEN deletion is common in PCa and is associated with decreased expression of PTEN and AR, which represents a poorer outcome Tissue Prognosis Lotan et al, 2011;Antonarakis et al, 2012;Choucair et al, 2012 Transforming growth factor-β1 (TGF-β1) Regulator of cellular proliferation, differentiation, and angiogenesis Decreased expression levels in PCa. Polymorphisms also aid the determination of PCa progression (single nucleotide polymorphisms at C-509T correlate with lower risk of aggressive PCa) Tissue Predictive Soulitzis et al, 2006;Faria et al, 2007;Brand et al, 2008 Trans-membrane prote- Ohta et al, 2003;…”