LncRNA LOXL1-AS1/miR-let-7a-5p/EGFR-related pathway regulates the doxorubicin resistance of prostate cancer DU-145 cells.

Our study aimed to investigate the effects of lncRNA LOXL1-AS1/miR-let-7a-5p/EGFR-axis on prostate cancer (PCa) progression. Microarray analysis was conducted to determine differentially expressed lncRNAs and mRNAs. Gene Set Enrichment analysis was implemented for verification of dys-regulated signaling pathways between DU-145 cells and doxorubicin-resistant prostate cancer DU-145 cells. Relative expression of lncRNA LOXL1-AS1 in doxorubicin-resistant prostate cancer DU-145 cells was analyzed by qRT-PCR. CCK-8 assay and flow cytometry analysis were employed to detect cell proliferation and apoptosis, respectively. Cell migration was performed by transwell assay. Furthermore, targeted relationships between lncRNA LOXL1-AS1 and miR-let-7a-5p, as well as miR-let-7a-5p and EGFR were predicted using bioinformatics analysis and validated by dual-luciferase reporter gene assay. Besides, tumor xenograft assay was utilized for verification of the roles of LOXL1-AS1 in PCa progression in vivo. Microarray analysis showed that lncRNA LOXL1-AS1 and EGFR were both downregulated, while miR-let-7a-5p was upregulated in doxorubicin-resistant prostate cancer DU-145 cells. MiR-let-7a-5p could target both lncRNA LOXL1-AS1 and EGFR to affect PCa progression. Upregulation of lncRNA LOXL1-AS1 promoted cell proliferation and migration, while suppressed cell apoptosis. Besides, it was further confirmed that EGFR was downregulated in drug-resistant PCa cells and negatively correlated with miR-let-7a-5p. Tumor xenograft assay verified that silence of lncRNA LOXL1-AS1 inhibited the tumor growth in vivo in DU-145 cells. Our results demonstrated that the lncRNALOXL1-AS1/miR-let-7a-5p/EGFR axis significantly affected proliferation, migration, and apoptosis of drug-resistant DU-145 Cells, which may provide us with a potential treatment strategy for drug-resistant PCa patients. © 2019 IUBMB Life, 2019.

Bai T ，Liu Y ，Li B 《-》

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.

Xue D ，Lu H ，Xu HY ，Zhou CX ，He XZ ... -  《-》

LncRNA LOXL1-AS1 facilitates the tumorigenesis and stemness of gastric carcinoma via regulation of miR-708-5p/USF1 pathway.

As one of the most life-threatening malignancies, gastric cancer is the third contributor of cancer mortalities globally. Increasing studies have proven the regulatory roles of lncRNAs in the development of diverse malignant tumours. But little is known about its function and molecular mechanism in gastric carcinoma. RT-qPCR was performed to measure the expression pattern of LOXL1-AS1 in gastric cancer. To ascertain its definite role, CCK-8, EdU, Western blot, transwell and sphere formation assays were adopted. RNA pull-down, RIP, ChIP and luciferase reporter assays were carried out to investigate the molecular mechanism of LOXL1-AS1 in gastric carcinoma. LOXL1-AS1 was highly expressed in tissues and cells of gastric cancer. The upregulation of LOXL1-AS1 predicted poor prognosis in gastric carcinoma. Our findings demonstrated that LOXL1-AS1 accelerated the deterioration of gastric cancer by inducing cell proliferation, migration, EMT and stemness. Moreover, the expression of USF1 in gastric cancer was higher than in normal control and LOXL1-AS1 negatively modulated USF1. Functionally, LOXL1-AS1 acted as a ceRNA to upregulate USF1 via sponging miR-708-5p. Besides, we confirmed USF1 promoted the transcription of stemness marker SOX2. Rescue experiments testified the stimulative role of LOXL1-AS1/miR-708-5p/USF1 pathway in gastric cancer progression. It was also validated that LOXL1-AS1 facilitated cell growth of gastric carcinoma in vivo. Our study unravelled that LOXL1-AS1/miR-708-5p/USF1 pathway contributed to the development of gastric cancer.

Sun Q ，Li J ，Li F ，Li H ，Bei S ，Zhang X ，Feng L ... -  《-》

LncRNA RHPN1-AS1 inhibition induces autophagy and apoptosis in prostate cancer cells via the miR-7-5p/EGFR/PI3K/AKT/mTOR signaling pathway.

LncRNA RHPN1-AS1 (RHPN1-AS1) has been confirmed to promote tumor progression in multiple cancers and is upregulated in prostate cancer (PCa), but whether it has an effect on PCa progression remains unclear. In this study, we found that PCa patients with high RHPN1-AS1 expression had a shorter survival time, and RHPN1-AS1 was significantly upregulated in PCa tissues and cells. Based on informatics analysis we predicted that miR-7-5p binds to 3'UTR of RHPN1-AS1 and epidermal growth factor receptor (EGFR) and verified it by luciferase reporter gene assay. Subsequently, we transfected PCa cells with RHPN1-AS1 overexpression vector (RHPN1-AS1), knockdown plasmids (sh-RHPN1-AS1) and/or miR-7-5p mimics or inhibitor and/or overexpression vector (EGFR) or small interfering RNA of EGFR (si-EGFR) or its control, and found that overexpression of RHPN1-AS1 inhibited miR-7-5p expression and promoted EGFR expression, silencing RHPN1-AS1 inhibited proliferation and invasion, and induced G2/M arrest, apoptosis and autophagy in PCa cells. 3MA (an inhibitor of autophagy)-mediated autophagy inhibition attenuated RHPN1-AS1 inhibition-induced apoptosis. Overexpression miR-7-5p or silencing EGFR promoted LC3-I to LC3-II conversion, enhanced autophagy activity, induced cleaved-caspase-3 expression and apoptosis in PCa cells. Furthermore, overexpression of RHPN1-AS1 promoted phosphorylation of phosphatidylinositol 3-kinase (PI3K), AKT and mTOR, inhibited LC3-I to LC3-II conversion and reduced apoptosis in PCa cells, while GSK2126458 (an inhibitor of PI3K) reversed the effect of RHPN1-AS1 on PCa cells. In summary, RHPN1-AS1 acted as a ceRNA of miR-7-5p to upregulate EGFR expression, silencing RHPN1-AS1 suppressed PCa tumor progression by inducing autophagy and apoptosis in PCa cells through the miR-7-5p/EGFR/PI3K/AKT/mTOR pathway.

Ma X ，Ren H ，Zhang Y ，Wang B ，Ma H ... -  《-》

Targeted-regulating of miR-515-5p by LncRNA LOXL1-AS1 on the proliferation and migration of trophoblast cells.

This study aims to elucidate the molecular mechanism of LOXL1-AS1 in proliferation and migration of trophoblast cells. We have used specific small interfering RNAs (si-RNA) and microRNA (mi-RNA) to knock down the target gene or m-RNA. In this regard we used following siRNAs: si-NC, si-LOXL1-AS1, pcDNA-NC, pcDNA-LOXL1-AS1, miR-NC, miR-515-5p. These si-RNA and miRNA were transfected into JeG-3 cells. Real-time quantitative PCR (RT-qPCR) was used to detect the expressions of LOXL1-AS1 and miR-515-5p. Western blot was used to detect Cyclin D1, matrix metalloproteinase 2 (MMP2), matrix metalloproteinases 9 (MMP9), phosphorylated p65 (p-p65), profilin of phosphorylated nuclear transcription factor κB (p-IκBα). MTT assay was used to detect cell survival rate, and the luciferase assay was used to detected the targeting relationship of LOXL1-AS1 and miR-515-5p. Our results showed that human placental trophoblast cells had higher level of LOXL1-AS1 in comparison to human choriocarcinoma cells, however, human placental trophoblast cells had lower level of miR-515-5p. In addition, the expression of CyclinD1, MMP2, MMP9 were significantly decreased in JeG-3 cell lines. We observed lower cell survival rate and lower cell migration number in JeG-3 cell lines. Our results demonstrated that LOXL1-AS1 could target miR-515-5p, and subsequently reverse the inhibitory effect of LOXL1-AS1 on proliferation and migration in JEG-3 cells. Also, lower expressions of p-p65 and p-IкBα in JeG-3 cells showed that miR-515-5p could reversed the inhibitory effect of LOXL1-AS1 on NF-κB signaling pathway. The low expression of LOXL1-AS1 inhibits the proliferation and migration of human choriocarcinoma cells, which might be related to miR-515-5p and NF-κB signaling pathways.

Zhang L ，Wan Q ，Zhou H 《-》