Long noncoding RNA HOTAIR regulates the invasion and metastasis of prostate cancer by targeting hepaCAM.

BACKGROUND: The role of HOX transcript antisense RNA (HOTAIR) has been proven to be important in tumorigenesis. However, how this molecule promotes metastasis and invasion in PCa is still unclear. METHODS: The relationship between HOTAIR and hepatocellular adhesion molecule (hepaCAM) in PCa was identified by immunohistochemistry, immunofluorescence, plasmid transfection, quantitative real-time PCR and immunoblotting. The regulatory effects of HOTAIR on hepaCAM and MAPK signalling and their key roles in PCa metastasis were investigated in vitro. RESULTS: The expression of HOTAIR was inversely correlated with hepaCAM in the blood and tissue of PCa patients. Here, hepaCAM was identified as a novel target gene of HOTAIR and was critical for the invasiveness of PCa. HOTAIR recruited PRC2 to the hepaCAM promoter, resulting in high levels of H3K27me3 and the absence of hepaCAM with an abnormally activated MAPK pathway. Both HOTAIR depletion and EZH2 inhibition could induce hepaCAM re-expression with inhibitory MAPK signalling and decrease the invasive and metastatic capabilities of PCa cells. CONCLUSIONS: This study demonstrates that HOTAIR promotes invasion and metastasis of PCa by decreasing the inhibitory effect of hepaCAM on MAPK signalling. Therefore, the HOTAIR/hepaCAM/MAPK axis may provide a new avenue towards therapeutic strategies and prognostic indicators for advanced prostate cancer.

PLCε knockdown overcomes drug resistance to androgen receptor antagonist in castration-resistant prostate cancer by suppressing the wnt3a/ß-catenin pathway.

Most prostate cancers (Pcas) develop into castration-resistant prostate cancer (CRPC) after receiving androgen deprivation therapy (ADT). The expression levels of PLCε and wnt3a are increased in Pca and regulate androgen receptor (AR) activity. However, the biological function and mechanisms of PLCε and wnt3a in CRPC remain unknown. In this study, we found that the expression levels of PLCε, wnt3a, and AR were significantly increased in CRPC tissues as well as bicalutamide-resistant-LNCaP and enzalutamide-resistant-LNCaP cells. In addition, PLCε knockdown partly restored the sensitivity of drug-resistant cells to bicalutamide and enzalutamide by inhibiting the activity of the wnt3a/ß-catenin/AR signaling axis. Interestingly, the resistance of LNCaP cells docetaxel is related to PLCε but not the wnt3a/ß-catenin pathway. We also found that the combination of PLCε knockdown and enzalutamide treatment synergistically suppressed cell proliferation, tumor growth, and bone metastasis using in vitro and in vivo experiments. Our study revealed that PLCε is involved in the progression of drug-resistance in CRPC and could be a new target for the treatment of CRPC.

Phospholipase C (PLC)ε Promotes Androgen Receptor Antagonist Resistance via the Bone Morphogenetic Protein (BMP)-6/SMAD Axis in a Castration-Resistant Prostate Cancer Cell Line.

BACKGROUND Primary therapy for patients with advanced prostate cancer (PCa) consists of androgen deprivation therapy targeting the androgen receptor (AR) axis. However, most tumors progress to castration-resistant prostate cancer (CRPC) within 18-24 months. The purpose of the present study was to investigate the mechanisms through which PCa acquires drug resistance after long-term treatment with AR antagonists. MATERIAL AND METHODS Online database analysis and bioinformatics analysis were performed to identify signaling activated during anti-androgen treatment. MTT assay was used to detect cell viability. RT-qPCR was performed to examine the mRNA expression of the indicated genes. Colony formation assay was performed to observe cell proliferation. Transwell assay was conducted to demonstrate invasive ability. Protein levels were determined by Western blot analysis and immunofluorescence assays. RESULTS An online database search and bioinformatics analysis indicated that bone morphogenetic protein (BMP)-6/SMAD signaling was activated in enzalutamide-resistant LNCaP cells. Furthermore, this signaling interaction was experimentally verified in bicalutamide- and enzalutamide-resistant LNCaP cells, which may be regulated by phospholipase C (PLC)ε and induced cell proliferation and invasion. Of note, a positive correlation was observed between PLCε and BMP-6 in CRPC tissue samples, which may promote bone metastasis and suggests a poor prognosis. CONCLUSIONS The present results suggest that targeting of PLCε/BMP-6/SMAD signaling may increase the sensitivity of CRPC to AR antagonists and inhibit tumor progression.

Comprehensive Analysis of Differential Gene Expression and Correlated Immune Infiltration in Bladder Cancer.

Background: Bladder cancer (BCa) is one of the most common urinary tract malignancies. Our study aimed to provide promising biomarkers for BCa screening and prognosis. Methods: BCa samples were obtained from Gene Expression Omnibus (GEO) datasets. Differentially expressed genes (DEGs) were analysed by GO/KEGG analysis. Univariate Cox hazard analysis and Kaplan Meier Curve clarified the relevance of DEGs and survival. Receiver operating characteristic (ROC) curve showed the discrimination ability of DEGs in BCa patient outcome prediction. RT-PCR was used to validate gene expression. Results: Overall, 61 common up regulated and 170 common down-regulated genes in BCa were obtained. DEGs were mainly enriched in proliferation and metastasis processes. CDC20, COL14A1, SPARCL1, TMOD1, RHOJ, FXYD6 and MFAP4 had clinical relevance to survival with high accuracy. CDC20, SPARCL1 and TMOD1 are promising biomarkers of BCa. CDC20, SPARCL1 and TMOD1 are involved in cancer immune infiltration. Conclusion: CDC20, SPARCL1 and TMOD1 are promising biomarkers of bladder cancer. In addition, CDC20, SPARCL1 and TMOD1 are involved in cancer immune infiltration, which provides new targets in immune therapy in bladder cancer.

[Corrigendum] Combination of phospholipase Cε knockdown with GANT61 sensitizes castration­resistant prostate cancer cells to enzalutamide by suppressing the androgen receptor signaling pathway.

Subsequently to the publication of this paper, an interested reader drew to the authors' attention that the same control ß­actin bands had apparently been included in the western blots featured in Fig. 5E and F, even though different experiments were presented in these figure parts. The authors have re­examined their data and realized that Fig. 5G was assembled incorrectly. The results from all the originally performed experiments were presented to the Editorial Office for our perusal. The revised version of Fig. 5, containing the correct ß­actin data for the western blots in Fig. 5F, is shown on the next page. The authors regret the inadvertent error that was made during the preparation of Fig. 5, and confirm that this error did not seriously affect the conclusions reported in the paper. The authors are grateful to the Editor of Oncology Reports for allowing them the opportunity to publish a Corrigendum, and all the authors agree to this Corrigendum. Furthermore, they apologise to the readership for any inconvenience caused.[Oncology Reports 41: 2689­2702, 2019; DOI: 10.3892/or.2019.7054].

Combination of phospholipase Cε knockdown with GANT61 sensitizes castration­resistant prostate cancer cells to enzalutamide by suppressing the androgen receptor signaling pathway.

Castration­resistant prostate cancer (CRPC) is a major challenge in the treatment of prostate cancer (PCa). Phospholipase Cε (PLCε), an oncogene, has been found to be involved in the carcinogenesis, tumor proliferation and migration of several types of cancer. The effects, however, of PLCε on CRPC remains unclear. In the present study, the expression of PLCε and glioma­associated homolog (Gli)­1/Gli­2 in benign prostatic hyperplasia (BPH), PCa and CRPC tissues and cells was investigated, and the correlations between PLCε and Gli­1/Gli­2 in CRPC tissues and cell lines were further explored. In addition, the effect of PLCε on cell proliferation and invasion was assessed in CRPC cell lines, and the sensitivity of EN­R and 22RV1 cells to enzalutamide following the downregulation of PLCε expression was determined using lentivirus­mediated shPLCε and/or treatment with specific Gli inhibitor GANT61. It was found that the PLCε expression was excessively upregulated in the majority of CRPC tissues, and PLCε positivity was linked to poor progression­free survival (PFS) and overall survival (OS) in patients with PCa. Furthermore, PLCε knockdown significantly suppressed CRPC cell proliferation and invasion. Of note, it was found that PLCε knockdown increased the sensitivity of CRPC cells to enzalutamide in vitro by suppressing androgen receptor (AR) activities via the non­canonical Hedgehog/Gli­2 and p­STAT3 signaling pathways. PLCε knockdown was shown to increase the sensitivity of CRPC cell xenografts to enzalutamide in vivo. Finally, the combination of PLCε knockdown with GANT61 significantly sensitized CRPC cells to enzalutamide. Collectively, the results of the present study suggest that PLCε is a potential therapeutic target for CRPC.

PLCε promotes urinary bladder cancer cells proliferation through STAT3/LDHA pathway­mediated glycolysis.

Phospholipase Cε (PLCε) and anaerobic glycolysis were determined to be involved in the development of human urinary bladder cancer (UBC), but the mechanisms remain unclear. In the present study, 64 bladder cancer specimens and 42 adjacent tissue specimens were obtained from 64 patients, and immunochemistry indicated that PLCε and lactate dehydrogenase (LDHA) are overexpressed in UBC. PLCε and LDHA were demonstrated to be positively correlated at transcription levels, indicating that one of these two genes may be regulated by another. To elucidate the mechanisms, PLCε was knocked down in T24 cells by short hairpin RNA, and then signal transducer and activator of transcription 3 (STAT3) phosphorylation and LDHA were determined to be downregulated, which indicated that PLCε may serve roles upstream of LDHA through STAT3 to regulate glycolysis in UBC. Furthermore, chromatin immunoprecipitation and luciferase reporter assays were performed to confirm that STAT3 could bind to the promoter of the LDHA gene to enhance its expression. A xenograft tumor mouse model also demonstrated similar results as the in vitro experiments, further confirming the role of PLCε in regulating bladder cell growth in vivo. Collectively, the present study demonstrated that PLCε may regulate glycolysis through the STAT3/LDHA pathway to take part in the development of human UBC.

Simvastatin delays castration­resistant prostate cancer metastasis and androgen receptor antagonist resistance by regulating the expression of caveolin­1.

The failure of androgen deprivation therapy in prostate cancer treatment mainly results from drug resistance to androgen receptor antagonists. Although an aberrant caveolin­1 (Cav­1) expression has been reported in multiple tumor cell lines, it is unknown whether it is responsible for the progression of castration­resistant prostate cancer (CRPC). Thus, the aim of the present study was to determine whether Cav­1 can be used as a key molecule for the prevention and treatment of CRPC, and to explore its mechanism of action in CRPC. For this purpose, tissue and serum samples from patients with primary prostate cancer and CRPC were analyzed using immunohistochemistry and enzyme­linked immunosorbent assay, which revealed that Cav­1 was overexpressed in CRPC. Furthermore, Kaplan­Meier survival analysis and univariate Cox proportional hazards regression analysis demonstrated that Cav­1 expression in tumors was an independent risk factor for the occurrence of CRPC and was associated with a shorter recurrence­free survival time in patients with CRPC. Receiver operating characteristic curves suggested that serum Cav­1 could be used as a diagnostic biomarker for CRPC (area under the curve, 0.876) using a cut­off value of 0.68 ng/ml (with a sensitivity of 82.1% and specificity of 80%). In addition, it was determined that Cav­1 induced the invasion and migration of CRPC cells by the activation of the H­Ras/phosphoinositide­specific phospholipase Cε signaling cascade in the cell membrane caveolae. Importantly, simvastatin was able to augment the anticancer effects of androgen receptor antagonists by downregulating the expression of Cav­1. Collectively, the findings of this study provide evidence that Cav­1 is a promising predictive biomarker for CRPC and that lowering cholesterol levels with simvastatin or interfering with the expression of Cav­1 may prove to be a useful strategy with which to prevent and/or treat CRPC.

HepaCAM inhibits the malignant behavior of castration-resistant prostate cancer cells by downregulating Notch signaling and PF-3084014 (a γ-secretase inhibitor) partly reverses the resistance of refractory prostate cancer to docetaxel and enzalutamide in vitro.

Castration-resistant prostate cancer (CRPC) continues to be a major challenge in the treatment of prostate cancer (PCa). The expression of hepatocyte cell adhesion molecule (HepaCAM), a novel tumor suppressor, is frequently downregulated or lost in PCa. Overactivated Notch signaling is involved in the development and progression of PCa, including CRPC. In this study, we found that the activities of Notch signaling were elevated, while HepaCAM expression was decreased in CRPC tissues compared with matched primary prostate cancer (PPC) tissues. In addition, HepaCAM negativity was found to be associated with a worse progression­free survival (PFS). Furthermore, the overexpression of HepaCAM induced by transfection with a HepaCAM overexpression vector (Ad­HepaCAM) exerted antitumor effects by decreasing the proliferation, and suppressing the invasion and migration of bicalutamide­resistant (Bica­R) cells and enzalutamide­resistant (Enza­R) cells. Importantly, we found that the antitumor effects of HepaCAM on the resistant cells were associated with the downregulation of Notch signaling. Moreover, we revealed that PF­3084014 (a γ­secretase inhibitor) re­sensitized Enza­R cells to enzalutamide, and sequential dual­resistant (E+D­R) cells to docetaxel. Additionally, the findings of this study demonstrated that the use of PF­3084014 alone exerted potent antitumor effect on the resistant cells in vitro. On the whole, this study indicates that HepaCAM potentially represents a therapeutic target and PF­3084014 may prove to a promising agent for use in the treatment of refractory PCa.