Long noncoding RNA MALAT1 enhances the docetaxel resistance of prostate cancer cells via miR-145-5p-mediated regulation of AKAP12.

Our present work was aimed to study on the regulatory role of MALAT1/miR-145-5p/AKAP12 axis on docetaxel (DTX) sensitivity of prostate cancer (PCa) cells. The microarray data (GSE33455) to identify differentially expressed lncRNAs and mRNAs in DTX-resistant PCa cell lines (DU-145-DTX and PC-3-DTX) was retrieved from the Gene Expression Omnibus (GEO) database. QRT-PCR analysis was performed to measure MALAT1 expression in DTX-sensitive and DTX-resistant tissues/cells. The human DTX-resistant cell lines DU145-PTX and PC3-DTX were established as in vitro cell models, and the expression of MALAT1, miR-145-5p and AKAP12 was manipulated in DTX-sensitive and DTX-resistant cells. Cell viability was examined using MTT assay and colony formation methods. Cell apoptosis was assessed by TUNEL staining. Cell migration and invasion was determined by scratch test (wound healing) and Transwell assay, respectively. Dual-luciferase assay was applied to analyse the target relationship between lncRNA MALAT1 and miR-145-5p, as well as between miR-145-5p and AKAP12. Tumour xenograft study was undertaken to confirm the correlation of MALAT1/miR-145-5p/AKAP12 axis and DTX sensitivity of PCa cells in vivo. In this study, we firstly notified that the MALAT1 expression levels were up-regulated in clinical DTX-resistant PCa samples. Overexpressed MALAT1 promoted cell proliferation, migration and invasion but decreased cell apoptosis rate of PCa cells in spite of DTX treatment. We identified miR-145-5p as a target of MALAT1. MiR-145-5p overexpression in PC3-DTX led to inhibited cell proliferation, migration and invasion as well as reduced chemoresistance to DTX, which was attenuated by MALAT1. Moreover, we determined that AKAP12 was a target of miR-145-5p, which significantly induced chemoresistance of PCa cells to DTX. Besides, it was proved that MALAT1 promoted tumour cell proliferation and enhanced DTX-chemoresistance in vivo. There was an lncRNA MALAT1/miR-145-5p/AKAP12 axis involved in DTX resistance of PCa cells and provided a new thought for PCa therapy.

MD-miniRNA could be a more accurate biomarker for prostate cancer screening compared with serum prostate-specific antigen level.

Prostate cancer and prostatic hyperplasia detection remains a great challenge, lacking of effective non-invasive and specific diagnostic biomarkers. In the current study, we aimed to identify the relative expression of plasma MD-miniRNA and its diagnostic performance in differentiating prostate cancer and prostatic hyperplasia patients from healthy controls, compared with serum prostate-specific antigen (PSA) level. All of the clinical participants (63 prostate cancer patients, 32 prostatic hyperplasia patients, and 50 healthy controls) were obtained from the Third Affiliated Hospital of Suzhou University in China between January 2013 and April 2014. Clinical characteristics were well matched. Plasma samples were extracted to test the relative expression of MD-miniRNA using the method of qRT-PCR. SPSS 22.0 statistical software package was used to analyze the data and GraphPad Prism 6.0 was used to generate the graphs. Relativity expression of plasma MD-miniRNA was significantly upregulated in prostate cancer, compared with prostatic hyperplasia patients and healthy controls. Serum PSA level revealed similar differences among these groups. MD-miniRNA presented a relatively high diagnostic accuracy with AUC of 0.86 (95 % CI 0.80-0.93) in differentiating prostate cancer patients from healthy controls. Simultaneously, MD-miniRNA was able to discriminate prostate cancer patients from prostatic hyperplasia controls with AUC of 0.79 (95 % CI 0.70-0.88). In addition, MD-miniRNA displayed a better diagnostic performance than PSA level. However, the panel of these two biomarkers revealed the best diagnostic performance, compared with either single biomarker. Results of this study showed that plasma MD-miniRNA could serve as a promising and noninvasive biomarker for diagnosing prostate cancer. Further large-scale studies are needed to confirm its clinical diagnosis accuracy.

[Expression of serum FSTL-1 in bone metastasis of prostate cancer and its clinical implication].

OBJECTIVE: To investigate the expression of follistatin-like protein 1 (FSTL-1) in bone metastasis of prostate cancer (BMPC), the correlation of serum FSTL-1 with the chronic inflammatory factor interleukin-6 (IL-6) and bone morphogenetic protein 6 (BMP6) , and the clinical application value of serum FSTL-1 in BMPC. METHODS: Using ELISA, we measured the expression levels of serum FSTL-1, IL-6, and BMP6 in 35 patients with BMPC and another 30 with benign prostatic hyperplasia (BPH) and performed correlation analysis on the data obtained. RESULTS: Compared with the BPH controls, the BMPC patients showed a significantly decreased expression of serum FSTL-1 ([34.45 ± 12.35] µg/L vs [20.23 ± 8.69] µg/L, P < 0.01) and increased levels of IL-6 ([11.21 ± 8.62] µg/L vs [23.56 ± 20.12] µg/L, P < 0.05) and BMP6 ([293.50 ± 39.72] µg/L vs [428.30 ± 178.40] µg/L, P < 0.05). There was a significant negative correlation between the level of serum FSTL-1 and those of IL-6 and BMP6 in the BMPC patients, with correlation coefficients of -0.971 and -0.972, respectively (P < 0.05). CONCLUSION: The expression of serum FSTL-1 decreases in patients with bone metastasis of prostate cancer, and it is correlated with the levels of inflammatory factor and cell transformation factor. This finding offers a novel biological marker for the development and progression of prostate cancer as well as a new biological target factor for its intervention.

Erratum: Decreased expression of ferroportin in prostate cancer.

[This corrects the article DOI: 10.3892/ol.2015.3363.].

Decreased expression of ferroportin in prostate cancer.

The present study examined the expression levels of ferroportin, a transmembrane protein that transports iron from the inside of a cell to the outside, in the prostate cancer PC3, DU145 and LNCAP cell lines, in the normal prostate RWPE2 cell line, and in tissue samples from different differentiation stages of prostatic carcinoma and prostatic hyperplasia. The study also investigated the role of ferroportin protein expression in the diagnosis and prognosis of prostate cancer. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were employed to measure the mRNA and protein expression levels of ferroportin in the PC3, DU145, LNCAP and RWPE2 cells. Immunohistochemistry was used to determine ferroportin protein expression in the prostate cancer and prostatic hyperplasia tissues. Compared with the normal prostate RWPE2 cells, ferroportin protein expression was significantly lower in the prostate cancer PC3, DU145 and LNCAP cells (P<0.05). Compared with the prostatic hyperplasia tissues, ferroportin protein expression was significantly reduced in the prostate cancer tissues (P<0.05). Overall, the expression levels of ferroportin in the prostate cancer tissues were lower than those in the normal prostate tissues, which may provide valuable clinical information for the diagnosis and prediction of disease progression in prostate cancer, and may indicate a potential therapeutic target for treating prostate cancer by regulating iron metabolism.