Gene microarray assessment of multiple genes and signal pathways involved in androgen-dependent prostate cancer becoming androgen independent

Prostate cancer downregulated SIRP-α modulates apoptosis and proliferation through p38-MAPK/NF-κB/COX-2 signaling

The present study investigated the regulatory mechanism of signal-regulatory protein (SIRP)-α in the apoptosis and proliferation of prostate cancer (CaP) cells. The expression profile of SIRP-α in prostate cancer cells was analyzed using reverse transcription-quantitative polymerase chain reaction and western blotting. Then SIRP-α function in CaP cells was further analyzed with the overexpression and RNA interference of SIRP-α. The results revealed that SIRP-α expression levels were decreased in CaP tissues and cell lines, with androgen-independent CaP exhibiting a lower SIRP-α expression compared with androgen-dependent CaP. Overexpression of SIRP-α resulted in a significantly reduced number of live CaP cells by enhancing apoptosis, whereas SIRP-α silencing increased CaP cell proliferation. Mechanistically, SIRP-α decreases cyclooxygenase-2 (COX-2) expression and cytokine production by negatively regulating p38 mitogen-activated protein kinase and nuclear factor-κB pathway. Therefore, SIRP-α knockdown decreases cell apoptosis by enhancing COX-2 expression. The present results indicate that SIRP-α may function as a novel negative regulator to modulate cellular proliferation, survival and migration in CaP cells. The heightened sensitivity of cells restoring SIRP-α function could be exploited in the development of therapeutics that may potentiate the antineoplastic effects of conventional cytokines or chemotherapeutic agents.

Downregulated microRNA-26a modulates prostate cancer cell proliferation and apoptosis by targeting COX-2

MicroRNA-26a (miR-26a) is expressed at lower levels in prostate cancer cells compared with normal prostate cells. However, the regulatory mechanism of miR-26a in tumorigenesis and metastasis is not clear. In the present study, the expression profile of cellular miR-26a was analyzed by reverse transcription-quantitative polymerase chain reaction. The potential target of miR-26a was identified by luciferase assay and western blotting. Examination of miR-26a function was performed by transfection with miR-26a mimics and inhibitor. It was found that miR-26a expression was decreased in prostate cancer tissues and cell lines, with androgen-independent prostate cancer (AIPC) showing lower miR-26a expression compared with androgen-dependent prostate cancer (ADPC). Overexpression of miR-26a by transfecting miR-26a mimics could significantly enhance apoptosis, and this upregulation of apoptosis was triggered by cytochrome c oxidase subunit II inhibition. Furthermore, it was found that lower miR-26a density resulted in an evidently poor prognosis. Understanding the important roles of miR-26a in regulating cell apoptosis in human prostate cancer cells may aid the exploration of AIPC transformation mechanisms and contribute to the development of miRNA-based therapy in the future.

Characterization of long non-coding RNA expression profiles in lymph node metastasis of early-stage cervical cancer

Pelvic lymph node metastasis (PLNM) is an independent prognostic parameter and determines the treatment strategies of cervical cancer. Increasing evidence indicates that long non-coding RNAs (lncRNAs) play a crucial role in the process of tumor biological functions. This study aimed to mine lymph node metastasis-associated lncRNAs and investigate their potential pathophysiological mechanism in cervical cancer lymph node metastasis. We applied the lncRNA-mining approach to identify lncRNA transcripts represented on Affymetrix human genome U133 plus 2.0 microarrays from Gene Expression Omnibus (GEO) and then by validation in clinical specimens. The biological role and molecular mechanism of these lncRNAs were predicted by bioinformatic analysis. Subsequently, a receiver operating characteristic (ROC) curve and survival curve were conducted to evaluate the diagnostic and prognostic value of candidate lncRNAs. In total, 234 differentially expressed lncRNAs were identified to significantly associate with pelvic lymph node metastasis in early-stage cervical cancer. Our qRT-PCR results were consistent with the mining analysis (P<0.05). The functional enrichment analysis suggested that these lncRNAs may be involved in the biological process of lymph node metastasis. The ROC curves demonstrated satisfactory discrimination power of MIR100HG and AC024560.2 with areas under the curve of 0.801 and 0.837, respectively. Survival curve also indicated that patients with high MIR100HG expression had a tendency of poor prognosis. This is the first study to successfully mine the lncRNA expression patterns in PLNM of early-stage cervical cancer. MIR100HG and AC024560.2 may be a potential biomarkers of PLNM and these lncRNAs may provide broader perspective for combating cervical cancer metastasis.

DNA methylation screening of primary prostate tumors identifies SRD5A2 and CYP11A1 as candidate markers for assessing risk of biochemical recurrence

BACKGROUND

Altered DNA methylation in CpG islands of gene promoters has been implicated in prostate cancer (PCa) progression and can be used to predict disease outcome. In this study, we determine whether methylation changes of androgen biosynthesis pathway (ABP)-related genes in patients' plasma cell-free DNA (cfDNA) can serve as prognostic markers for biochemical recurrence (BCR).

METHODS

Methyl-binding domain capture sequencing (MBDCap-seq) was used to identify differentially methylated regions (DMRs) in primary tumors of patients who subsequently developed BCR or not, respectively. Methylation pyrosequencing of candidate loci was validated in cfDNA samples of 86 PCa patients taken at and/or post-radical prostatectomy (RP) using univariate and multivariate prediction analyses.

RESULTS

Putative DMRs in 13 of 30 ABP-related genes were found between tumors of BCR (n = 12) versus no evidence of disease (NED) (n = 15). In silico analysis of The Cancer Genome Atlas data confirmed increased DNA methylation of two loci-SRD5A2 and CYP11A1, which also correlated with their decreased expression, in tumors with subsequent BCR development. Their aberrant cfDNA methylation was also associated with detectable levels of PSA taken after patients' post-RP. Multivariate analysis of the change in cfDNA methylation at all of CpG sites measured along with patient's treatment history predicted if a patient will develop BCR with 77.5% overall accuracy.

CONCLUSIONS

Overall, increased DNA methylation of SRD5A2 and CYP11A1 related to androgen biosynthesis functions may play a role in BCR after patients' RP. The correlation between aberrant cfDNA methylation and detectable PSA in post-RP further suggests their utility as predictive markers for PCa recurrence. .