Xuechao Wan

Identification of Novel AR-Targeted MicroRNAs Mediating Androgen Signalling through Critical Pathways to Regulate Cell Viability in Prostate Cancer

MicroRNAs (miRNAs) have been recognized as significantly involved in prostate cancer (PCa). Since androgen receptor (AR) plays a central role in PCa carcinogenesis and progression, it is imperative to systematically elucidate the causal association between AR and miRNAs, focusing on the molecular mechanisms by which miRNAs mediate AR signalling. In this study, we performed a series of time-course microarrays to observe the dynamic genome-wide expressions of mRNAs and miRNAs in parallel in hormone-sensitive prostate cancer LNCaP cells stimulated by androgen. Accordingly, we introduced Response Score to identify AR target miRNAs, as well as Modulation Score to identify miRNA target mRNAs. Based on theoretical identification and experimental validation, novel mechanisms addressing cell viability in PCa were unravelled for 3 miRNAs newly recognized as AR targets. (1) miR-19a is directly up-regulated by AR, and represses SUZ12, RAB13, SC4MOL, PSAP and ABCA1, respectively. (2) miR-27a is directly up-regulated by AR, and represses ABCA1 and PDS5B. (3) miR-133b is directly up-regulated by AR, and represses CDC2L5, PTPRK, RB1CC1, and CPNE3, respectively. Moreover, we found miR-133b is essential to PCa cell survival. Our study gives certain clues on miRNAs mediated AR signalling to cell viability by influencing critical pathways, especially by breaking through androgen’s growth restriction effect on normal prostate tissue.

Androgen-induced miR-27A acted as a tumor suppressor by targeting MAP2K4 and mediated prostate cancer progression

Prostate cancer (PCa) is the most commonly diagnosed and secondly leading cause of cancer death among males. But the precise mechanism of prostate cancer progression, including microRNAs (miRNAs) functioning in it, is still needs further study. We found miR-27a to be down-regulated in prostate cancer, and we investigated the mechanism and role of miRNA-27a in prostate cancer. MiR-27a, a transcriptional target of AR, was an androgen-induced miRNA in LNCaP cells. In castration-resistant prostate cancer (CRPC) cells, we for the first time reported that miR-27a was downregulated by PI3K signaling. MiR-27a functioned as a tumor suppressor in prostate cancer. Over-expression of miR-27a decreased prostate cancer cell proliferation and migration, and induced prostate cancer cell cycle arrest and apoptosis. MAP2K4, miR-27as direct target gene, functioned as an oncogene in prostate cancer by reducing G1-S phase arrest and inhibiting cell apoptosis of prostate cancer cells. In conclusion, miR-27a functions as a tumor suppressor by suppressing MAP2K4 which acts as an oncogene in prostate cancer cell lines; we also provided a new mechanism of castration-resistant prostate cancer mediated by miR-27a that downregulation of miR-27a caused by aberrant AR signaling and PI3K/Akt signaling after androgen deprivation therapy (ADT) would promote the progression of castration-resistant prostate cancer.

Downregulation of long non-coding RNA HCG11 predicts a poor prognosis in prostate cancer

Long non-coding RNAs (lncRNA) have been reported as key regulators in the progression and metastasis of prostate cancer (PCa). In this study, we found that the expression levels of HCG11 in PCa tissues were significantly lower than those in non-tumor tissues in publically available databases and in human PCa samples. Our results showed the expression levels of HCG11 in patients with PCa were associated with the age, Lymph Node Status (LN status), preoperative PSA level, Gleason score, and biochemical recurrence (BCR). Kaplan-Meier analysis indicated that downregulation of HCG11 expression in tissues was associated with poor survival of PCa patients. GO and KEGG pathway analysis were applied to explore the potential roles of HCG11. Moreover, a HCG11 mediated ceRNA network was built using co-expression relationships of the differentially expressed mRNAs and miRNAs. We believed that this study will provide a potential new therapeutic and prognostic target for prostate cancer.

KDM1A triggers androgen-induced miRNA transcription via H3K4me2 demethylation and DNA oxidation.

Androgen receptor (AR) is a ligand dependent transcription factor that regulates the transcription of target genes. AR activity is closely involved in the maintenance and progression of prostate cancer. After the binding with androgen, AR moves into nucleus and binds to DNA sequence containing androgen response elements (ARE). Flavin‐dependent monoamine oxidase KDM1A is necessary for AR driven transcription while the mechanism remains unclear.

Androgen-induced miR-135a acts as a tumor suppressor through downregulating RBAK and MMP11, and mediates resistance to androgen deprivation therapy

The main challenge in the treatment of prostate cancer (PCa) is that the majority of patients inevitably develop resistance to androgen deprivation. However, the mechanisms involved in hormone independent behavior of PCa remain unclear. In the present study, we identified androgen-induced miR-135a as a direct target of AR. Functional studies revealed that overexpression of miR-135a could significantly decrease cell proliferation and migration, and induce cell cycle arrest and apoptosis in PCa. We identified RBAK and MMP11 as direct targets of miR-135a in PCa by integrating bioinformatics analysis and experimental assays. Mechanistically, miR-135a repressed PCa migration through downregulating MMP11 and induced PCa cell cycle arrest and apoptosis by suppressing RBAK. Consistently, inverse correlations were also observed between the expression of miR-135a and RBAK or MMP11 in PCa samples. In addition, low miR-135a and high RBAK and MMP11 expression were positively correlated with PCa progression. Also, PI3K/AKT pathway was confirmed to be an upstream regulation signaling of miR-135a in androgen-independent cell lines. Accordingly, we reported a resistance mechanism to androgen deprivation therapy (ADT) mediated by miR-135a which might be downregulated by androgen depletion and/or PI3K/AKT hyperactivation, in castration-resistant prostate cancer (CRPC), thus promoting tumor progression. Taken together, miR-135a may represent a new diagnostic and therapeutic biomarker for castration-resistant PCa.

UHRF1 overexpression is involved in cell proliferation and biochemical recurrence in prostate cancer after radical prostatectomy

BackgroundBiochemical recurrence (BCR) is widely used to define the treatment success and to make decisions on if or how to initiate a secondary therapy, but uniform criteria to define BCR after radical prostatectomy (RP) is not yet completely assessed. UHRF1 has a unique function in regulating the epigenome by linking DNA methylation with histone marks. The clinical value of UHRF1 in PCa has not been well done. Therefore, we evaluated the prognostic significance of UHRF1.MethodUHRF1 expression in PCa cells was monitored by qRT-PCR and Western blot analyses. UHRF1 expression was knocked down using specific siRNAs, and the effects of knockdown on the proliferation, migration, cell cycle, and apoptosis of PCa cell lines were investigated. UHRF1 protein expression was evaluated in 225 PCa specimens using immunohistochemistry in tissue microarrays. Correlations between UHRF1 expression and the clinical features of PCa were assessed.ResultsThe results showed that UHRF1 was overexpressed in almost all of the PCa cell lines. In PCa cells, UHRF1 knockdown inhibited cell proliferation and migration, and induced apoptosis. UHRF1 expression levels were correlated with some clinical features of PCa. Multivariate analysis showed that UHRF1 expression was an independent prognostic factor for biochemical recurrence-free survival.ConclusionsUHRF1 functions as an oncogene in prostate cancer and appears to be capable of predicting the risk of biochemical recurrence in PCa patients after radical prostatectomy, and may serve as a potential therapeutic target for PCa.

An androgen reduced transcript of LncRNA GAS5 promoted prostate cancer proliferation

Prostate cancer (PCa) becomes a leading cause of death in males nowadays. Recent reports showed that androgen-responsive long non-coding RNAs played important roles in tumorigenesis and progression of PCa. In this study, we focused on a special transcript of GAS5 (ENST00000456293.5, GAS5-007), which was reported as a tumor suppressor. Here, we demonstrated GAS5-007 was reduced by androgen treatment and inhibited by AR. Next, we explored the expression level of GAS, finding the expression of it in PCa tissue was higher than normal tissue in both public databases and human tissue samples. Functional analysis of GAS5 showed it was related to regulating translational elongation, protein biosynthesis, and transcription. Moreover, we observed GAS5-007 knockdown inhibited the proliferation, cell cycle and promoted cell apoptosis of PCa. We also constructed a GAS5-miRNA network to explain the different roles of different GAS5 transcripts in PCa. This study provides novel insights to identify potential diagnostic biomarker and therapy target for prostate cancer in clinical treatment.

A transcriptional target of androgen receptor, miR-421 regulates proliferation and metabolism of prostate cancer cells.

Prostate cancer is one of the most common malignancies, and microRNAs have been recognized to be involved in tumorigenesis of various kinds of cancer including prostate cancer (PCa). Androgen receptor (AR) plays a core role in prostate cancer progression and is responsible for regulation of numerous downstream targets including microRNAs. This study identified an AR-repressed microRNA, miR-421, in prostate cancer. Expression of miR-421 was significantly suppressed by androgen treatment, and correlated to AR expression in different prostate cancer cell lines. Furthermore, androgen-activated AR could directly bind to androgen responsive element (ARE) of miR-421, as predicted by bioinformatics resources and demonstrated by ChIP and luciferase reporter assays. In addition, over-expression of miR-421 markedly supressed cell viability, delayed cell cycle, reduced glycolysis and inhibited migration in prostate cancer cells. According to the result of miR-421 target genes searching, we focused on 4 genes NRAS, PRAME, CUL4B and PFKFB2 based on their involvement in cell proliferation, cell cycle progression and metabolism. The expression of these 4 downstream targets were significantly repressed by miR-421, and the binding sites were verified by luciferase assay. Additionally, we explored the expression of miR-421 and its target genes in human prostate cancer tissues, both in shared microarray data and in our own cohort. Significant differential expression and inverse correlation were found in PCa patients.

Co-expression analysis revealed PTCH1-3’UTR promoted cell migration and invasion by activating miR-101-3p/SLC39A6 axis in non-small cell lung cancer: implicating the novel function of PTCH1

Metastasis is the most common cause of mortality for non-small cell lung cancer (NSCLC). PTCH1, a receptor of Hedgehog (Hh) pathway, is reported to suppress cell proliferation. Interestingly, our previous study showed PTCH1 silencing promoted cell proliferation but inhibited cell migration and invasion of NSCLC cells. However, the precise mechanisms of PTCH1 regulating NSCLC metastasis remain unclear. PTCH1 has multiple splicing variants, which all share the same 3’UTR sequence, meanwhile, emerging studies have shown competing endogenous RNAs (ceRNAs) play important roles in regulating cancer progression. Therefore, we hypothesized the functions of PTCH1-3’UTR in NSCLC in present study to reveal its role as a ceRNA. Here, we find overexpression of PTCH1-3’UTR promotes cell migration, invasion and adhesion, but does not affect cell proliferation in NSCLC cells. By combining weighted correlation network analysis (WGCNA) analysis and experimental validation, we reported PTCH1-3’UTR acted as a sponge to absorb miR-101-3p and promoted SLC39A6 expression. Moreover, we observed low expression of miR-101-3p and PTCH1 and high SLC39A6 levels were positively correlated with NSCLC progression. Therefore, our results help to understand the function of PTCH1 in NSCLC tumorigenesis and provide novel insights for the prevention of NSCLC metastasis.

Overexpression of AR-regulated lncRNA TMPO-AS1 correlates with tumor progression and poor prognosis in prostate cancer

Prostate cancer (PCa) is a leading cause of death in males all over the world; besides, the diagnosis and therapy of it are still challenging. Researchers have revealed that long non‐coding RNAs (lncRNAs) play important roles in the genesis and progression of human cancers, including PCa.