lncRNA PCNAP1 predicts poor prognosis in breast cancer and promotes cancer metastasis via miR­340­5p­dependent upregulation of SOX4.

The high metastatic rate of breast cancer is the significant cause of its poor prognosis. The long noncoding RNA (lncRNA) proliferating cell nuclear antigen pseudogene 1 (PCNAP1) plays important roles in the initiation and progression of cancers; however, its regulatory function and molecular mechanism in breast cancer metastasis remains unknown. Therefore, we investigated the roles of lncRNA PCNAP1 in breast cancer metastasis by modulating the microRNA (miR)­340­5p/SOX4 axis using quantitative real­time PCR, in vivo mouse models, nucleo­cytoplasmic separation, western blot analysis, scratch assays, Transwell assays, luciferase reporter assays and MS2­RIP, in vitro and in vivo. lncRNA PCNAP1 was found to be upregulated in human breast cancer tissues, and high lncRNA PCNAP1 levels predicted poor overall survival. Function assays showed that knockdown of lncRNA PCNAP1 suppressed the migration and invasion of breast cancer cells in vitro and in vivo. Mechanistically, lncRNA PCNAP1 functioned as a competing endogenous (ce)RNA for miR­340­5p to facilitate the expression of its target gene SRY­box transcription factor 4 (SOX4), promoting migration and invasion of breast cancer cells. Overall, we found that lncRNA PCNAP1 predicted a poor prognosis in breast cancer and promoted cancer metastasis via miR­340­5p­dependent upregulation of SOX4 expression. These results suggest that lncRNA PCNAP1 has potential as an alternative therapeutic target to suppress breast cancer metastasis.

MicroRNA-340-5p suppressed rheumatoid arthritis synovial fibroblast proliferation and induces apoptotic cell number by targeting signal transducers and activators of transcription 3.

Rheumatoid arthritis is a chronic systemic autoimmune disease. In this study, the role of microRNA-340-5p in rheumatoid arthritis was investigated. qRT-PCR was used to detect the expression of microRNA-340-5p in serums, synovial tissues, and fibroblast-like synoviocytes from patients and healthy participants. Cell proliferation rate, cell cycle and apoptotic cell numbers were measured by CCK-8 and flow cytometry assays. The expression of pro-inflammation factors was determined by ELISA. Our data showed that the expression of microRNA-340-5p was greatly suppressed in rheumatoid arthritis serums, synovial tissues and rheumatoid arthritis-fibroblast-like synoviocytes compared to that in healthy controls. Over-expression of microRNA-340-5p greatly suppressed cell proliferation, promoted cell apoptosis, and suppressed the expression of inflammation factors in rheumatoid arthritis fibroblast-like synoviocytes. Additionally, STAT3 was a target of microRNA-340-5. Overexpression of STAT3 could reverse the outcome of microRNA-340-5p on cell proliferation and apoptosis in rheumatoid arthritis fibroblast-like synoviocytes. The findings in our study demonstrated that microRNA-340-5p may serve as a potential target for therapeutic direction for patients with rheumatoid arthritis.

[Role of miRNA-340 in modulating gastric cancer cell proliferation and bioinformatic analysis].

OBJECTIVE: To investigate the mechanism of miRNA-340 for regulating the proliferation of gastric cancer (GC) cells and predict its interacting circular RNAs (circRNAs), its downstream target genes and the involved signaling pathways. METHODS: The differentially expressed miRNAs in GC cell lines were analyzed and screened using miRNA microarrays. The expression level of miRNA-340 in 21 pairs of GC tissues and adjacent normal tissues was detected using real-time PCR. MTT and EdU assays were performed to examine the effect of miRNA-340 on the proliferation ability of HFE145 and BGC-823 cells. We also tested the effect of miRNA-340 inhibition on subcutaneous tumorigenesis of GC cells in a nude mouse model. The downstream target genes of miRNA-340 and the probable signal pathways were predicted online using Targetscan and DAVID database, respectively. The interacting circRNAs of miRNA-340 were analyzed using starBase platform. RESULTS: Among the differentially expressed miRNAs, miRNA-340 was significantly down-regulated in GC cell lines. Real-time PCR results showed that the expression of miRNA-340 was significantly lower in GC tissues than in the adjacent tissues (P < 0.05). MTT and EdU cell proliferation assays showed that miRNA-340 overexpression inhibited the proliferation of GC cells in vitro. In the nude mouse models, the proliferation of GC cells transfected with miRNA-340 inhibitor was obviously enhanced. Bioinformatics analysis suggested that miRNA-340 had 21 target genes with 3 or more conserved sites, and these genes were involved in tumorigenesis and invasion. The top 10 circRNAs were selected as the most powerful sponge circRNAs interacting with miRNA-340. CONCLUSIONS: miRNA-340 may play the role of a tumor suppressor in tumorigenesis and progression. Overexpression of miRNA-340 suppress the proliferation of GC cells, suggesting its involvement in the development of GC along with multiple circRNAs.

Role of miRNA-340 in modulating gastric cancer cell proliferation and bioinformatic analysis / 南方医科大学学报

OBJECTIVE@#To investigate the mechanism of miRNA-340 for regulating the proliferation of gastric cancer (GC) cells and predict its interacting circular RNAs (circRNAs), its downstream target genes and the involved signaling pathways.@*METHODS@#The differentially expressed miRNAs in GC cell lines were analyzed and screened using miRNA microarrays. The expression level of miRNA-340 in 21 pairs of GC tissues and adjacent normal tissues was detected using real-time PCR. MTT and EdU assays were performed to examine the effect of miRNA-340 on the proliferation ability of HFE145 and BGC-823 cells. We also tested the effect of miRNA-340 inhibition on subcutaneous tumorigenesis of GC cells in a nude mouse model. The downstream target genes of miRNA-340 and the probable signal pathways were predicted online using Targetscan and DAVID database, respectively. The interacting circRNAs of miRNA-340 were analyzed using starBase platform.@*RESULTS@#Among the differentially expressed miRNAs, miRNA-340 was significantly down-regulated in GC cell lines. Real-time PCR results showed that the expression of miRNA-340 was significantly lower in GC tissues than in the adjacent tissues ( < 0.05). MTT and EdU cell proliferation assays showed that miRNA-340 overexpression inhibited the proliferation of GC cells in vitro. In the nude mouse models, the proliferation of GC cells transfected with miRNA-340 inhibitor was obviously enhanced. Bioinformatics analysis suggested that miRNA-340 had 21 target genes with 3 or more conserved sites, and these genes were involved in tumorigenesis and invasion. The top 10 circRNAs were selected as the most powerful sponge circRNAs interacting with miRNA-340.@*CONCLUSIONS@#miRNA-340 may play the role of a tumor suppressor in tumorigenesis and progression. Overexpression of miRNA-340 suppress the proliferation of GC cells, suggesting its involvement in the development of GC along with multiple circRNAs.

MicroRNA-340 inhibits invasion and metastasis by downregulating ROCK1 in breast cancer cells.

MicroRNAs (miRNAs/miRs) are 19-25 nucleotide-long, non-coding RNAs that regulate the expression of target genes at the post-transcriptional level. In the present study, the role of miR-340 in breast cancer (BC) was investigated. The overexpression of miR-340 significantly inhibited the proliferation, migration and invasion of human breast MDA-MB-231 cancer cells in vitro. The Rho-associated, coiled-coil containing protein kinase 1 (ROCK1) gene was identified as a target of miR-340; its expression was downregulated by overexpression of miR-340 by binding to its 3'-untranslated region. The short interfering RNA-mediated silencing of ROCK1 was also performed, which phenocopied the effects of miR-340 overexpression. An inhibitor of miR-340 was used to suppress miR-340 expression, which led to increased expression of ROCK1, thus improving the proliferation, migration and invasion of MDA-MB-231 cells. Data from the present study suggest that miR-340 inhibits MDA-MB-231 cell growth and its downregulation may lead to the progression and metastasis of BC. Thus, miR340 may act as a tumor-suppressor agent that could serve a key role in the diagnosis and therapy of BC.

miRNA-340 inhibits osteoclast differentiation via repression of MITF.

Many miRNAs play critical roles in modulating various biological processes of osteoclast differentiation and function. Microphthalmia-associated transcription factor (MITF), a target of miR-340, served as pivotal transcription factor involved in osteoclast differentiation. However, the role of miR-340 and MITF during osteoclast differentiation has not yet been clearly established. Tartrate-resistant acid phosphatase (TRAP) staining assay was performed to identify osteoclasts differentiated from bone marrow-derived macrophages (BMMs). Quantitative reverse transcription PCR (qRT-PCR) or Western blotting was undertaken to examine the mRNA or protein expression respectively. Luciferase reporter assay was performed to investigate the interaction between miR-340 and MITF. MITF was knocked down and miR-340 was overexpressed and transfected into BMMs to detect their effects on osteoclast differentiation. Firstly, qRT-PCR analysis showed that miR-340 was down-regulated during osteoclast differentiation stimulated by macrophage-colony stimulating factor (M-CSF) and receptor activator of nuclear factor (NF)-κB (RANK) ligand (RANKL). Besides, we found that overexpression of miRNA-340 inhibited osteoclast differentiation and suppressed both the mRNA and protein level of MITF. Finally, Western blot and qRT-PCR analysis revealed that silencing MITF inhibited TRAP, calcitonin receptor, V-ATPase d2, and cathepsin K. miR-340 suppresses osteoclast differentiation by inhibiting MITF. Our findings may provide promising therapeutic targets for osteoclast-associated diseases.