EIF4A3-induced circBRWD3 promotes tumorigenesis of breast cancer through miR-142-3p_miR-142-5p/RAC1/PAK1 signaling

CircBRWD3 is a newly discovered circRNA, and its potential function has not been probed. Here, we aimed to molecularly dissect the role of circBRWD3 in the tumorigenesis and progression of breast cancer (BC). qRT-PCR analysis revealed that circBRWD3 expression was dramatically upregulated in BC tissues, a feature that was positively correlated with the poor prognosis of patients with BC. CircBRWD3 knockdown repressed cell proliferation and metastasis, while promoting cell apoptosis in vitro. Consistently, an in vivo circBRWD3 deficiency model exhibited suppressed tumor metastasis and oncogenesis. On the other hand, circBRWD3 overexpression promoted cancer cell activity and tumorigenesis. Further, mechanistic studies elucidated that circBRWD3 sponged both miR-142-3p and miR-142-5p to modulate RAC1 expression, which subsequently activated the RAC1/PAK1 signaling to facilitate the tumorigenesis and progression of BC. Moreover, we discovered that EIF4A3 facilitated circBRWD3 expression by targeting the upstream of BRWD3 pre-mRNA. In conclusion, our study reveals that circBRWD3 facilitates BC tumorigenesis by regulating the circBRWD3/miR-142-3p_miR-142-5p /RAC1/PAK1 axis. In addition, circBRWD3 expression is positively regulated by an RNA-binding protein, EIFA3. Our results provide valuable scientific data for early diagnosis and therapy for breast cancer patients.

Clinical significance of miR-142-5p in spinal cord injury caused by spinal trauma and its functional role in the regulation of inflammation

OBJECTIVE

Spinal cord injury (SCI) is a severe traumatic disease in the central nervous system, and can result in neuronal injury. Altered miRNA expression is identified to be involved in the pathogenesis of SCI.

DESIGN

This study investigated the clinical value of miR-142-5p in SCI patients, and explored its functional role in the regulation of inflammatory.

SETTING

The First Affiliated Hospital of Soochow University.

PARTICIPANTS

Ninety-eight patients with acute spinal trauma.

INTERVENTIONS

All patients were recruited, and divided into complete SCI group, incomplete SCI group and normal nerve function group.

OUTCOME MEASURES

Real-time quantitative PCR (qRT-PCR) was used to detect the expression levels of miR-142-5p. CCK-8 and flow cytometry assay were performed to evaluate the cell viability and apoptosis. ELISA assay was applied to estimate the levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α).

RESULTS

Serum miR-142-5p level was significantly increased in SCI patients, especially the complete SCI cases. ROC curve analysis suggested miR-142-5p could distinguish SCI patients from normal nerve function patients and was associated with the severity of SCI. A positive association was detected between miR-142-5p and serum levels of IL-6, TNF-α in SCI patients. Downregulation of miR-142-5p significantly reduced the protein levels of both IL-6 and TNF-α in LPS treated PC12 cells, and weakened LPS induced cell apoptosis.

CONCLUSION

MiR-142-5p is a potential biomarker for the occurrence of SCI in acute spinal trauma patients. Downregulation of miR-142-5p plays an anti-inflammatory effect for SCI patients.

MiR-142-5p directly targets cyclin-dependent kinase 5-mediated upregulation of the inflammatory process in acquired middle ear cholesteatoma

MicroRNAs (miRNAs) play important roles in the regulation of cell proliferation, differentiation, apoptosis, and inflammatory responses. MiR-142-5p is an important inflammation-associated miRNA, whose abnormal expression has been associated with a variety of inflammation-related diseases. However, the role and signaling pathways targeted by miR-142-5p in acquired middle ear cholesteatoma (AMEC) have not been fully elucidated. Cyclin-dependent kinase 5 (CDK5), a special member of the CDK family compared with classic cyclins that plays a critical role in the inflammatory response. In this study, we investigated the roles of miR-142-5p and CDK5 in inflammatory responses in AMEC. Our results revealed that the expression of miR-142-5p was significantly reduced in AMEC, and was negatively correlated with the expression of CDK5 (r=-0.5451). We also found that miR-142-5p can inhibit CDK5 expression by directly target 3' untranslated region (UTR) of CDK5. Additionally, our findings indicated that the increased expression of CDK5 induces the secretion of inflammatory cytokines. In order to further confirm the involvement of miR-142-5p in the regulation of the inflammatory response in AMEC through its inhibitory effect on CDK5 expression, we studied the inflammatory response in HaCaT cells transfected with small interfering RNA against CDK5 (si-CDK5) and a miR-142-5p inhibitor. The results confirmed that miR-142-5p regulates the inflammatory response in AMEC by downregulating CDK5. In summary, miR-142-5p directly inhibits the CDK5-mediated upregulation of inflammatory cytokines in AMEC, which makes it a potential therapeutic target in this disease.

LncRNA FGD5-AS1 promotes the malignant phenotypes of ovarian cancer cells via targeting miR-142-5p

Long non-coding RNAs (lncRNAs) have been reported to participate in regulating gene expression and are related to tumor progression. FGD5 antisense RNA 1 (FGD5-AS1) facilitates the progression of various tumors. However, the expression and function of FGD5-AS1 in ovarian cancer (OC) and its mechanism of action are not yet clear. Real-time polymerase chain reaction (RT-PCR) was employed to explore the expression levels of FGD5-AS1 and miR-142-5p in OC. The relationship between the expression of FGD5-AS1 and clinicopathological indicators of OC patients was analyzed by χ² test. CCK-8 assay, BrdU assay, and Transwell assay were carried out to detect cell proliferation, migration, as well as invasion, respectively. Subcutaneous tumorigenesis experiment and lung metastasis model were used to examine the biological effects of FGD5-AS1 in OC in vivo. Dual luciferase reporter gene assay or RIP experiment was employed to explore the targeting relationship between FGD5-AS1 and miR-142-5p, as well as miR-142-5p and PD-L1 3'UTR. First, we found that FGD5-AS1 was markedly up-regulated in OC. Moreover, its high expression level was associated with positive local lymph node metastasis and higher T stage in OC patients. Gain-of-function and loss-of-function assays demonstrated that FGD5-AS1 facilitated the proliferation, migration, as well as invasion of OC cells. Mechanistically, it was revealed that FGD5-AS1 targeted miR-142-5p to repress its expression and function. Furthermore, miR-142-5p has a binding site for 3' UTR of PD-L1, and FGD5-AS1 could positively regulate PD-L1 expression via repressing miR-142-5p. The present study reports that FGD5-AS1/miR-142-5p/PD-L1 axis is involved in regulating OC progression.

MicroRNA expression profiling and the role of ALCAM modulating tumor growth and metastasis in benzo[a]pyrene-transformed 16HBE cells

Benzo[a]pyrene (BaP) is a potent carcinogen and microRNAs (miRNAs) may play an important role in carcinogenesis. Activated leukocyte cell adhesion molecule (ALCAM) was up-regulated in BaP-transformed 16HBE cell line (THBEc1), and may be a key molecule for THBEc1 cells to gain and maintain the malignant phenotype. Here we screened the differentially expressed miRNAs which resulted in up-regulation of ALCAM in THBEc1 cells by comparing miRNA expression profiles between THBEc1 and 16HBE (HBE) cells. Results showed that a total of 555 miRNAs differentially expressed between THBEc1 and HBE cells, of which 351 miRNAs were down-regulated and 204 miRNAs were up-regulated in THBEc1 cells. MiR-152-3p, miR-142-5p and miR-211-5p down-regulated in THBEc1 cells were demonstrated to participate in the regulation of ALCAM. With THBEc1 as a tumor cell model, we determined the role of ALCAM in tumor growth and metastasis employing two ALCAM knockout THBEc1 cell lines via CRISPR/Cas9 technology. Results showed that ALCAM knockout inhibited colony formation and tumor growth, but enhanced cell migration and lung metastasis of THBEc1 cells. In conclusion, miR-152-3p/ALCAM, miR-142-5p/ALCAM and miR-211-5p/ALCAM axes may be involved in BaP-induced carcinogenesis. BaP might induce up-regulation of ALCAM via inhibiting miR-152-3p, miR-142-5p and miR-211-5p, which in turn allows ALCAM to exert its role promoting cell proliferation and tumor growth, and suppressing cell migration and metastasis.

MiR-142-5p Suppresses Tumorigenesis by Targeting PIK3CA in Non-Small Cell Lung Cancer

BACKGROUND/AIMS

Numerous studies have demonstrated that aberrant microRNA (miRNA) expression is involved in human disease including cancer. To date, the potential miRNAs regulating lung cancer growth and progression are not fully identified yet.

METHODS

In this study, the expression of miR-142-5p was measured in non-small cell lung cancer tissue and cell lines by qRT-PCR. The functional assays including the cell viability, colony formation, cell migration and invasion were performed in miR-142-5p mimic or inhibitor transfected cell lines (in vitro) and the cell tumorigenesis in nude mice (in vivo). The fluorescence ratios of cell viability were recorded using a multi-plate reader (Synergy 2, BioTek, Winooski, VT, USA) and the colonies were counted using an ELIspot Bioreader 5000 (BIO-SYS, Karben, GE).

RESULTS

MiR-142-5p was significantly downregulated in non-small cell lung cancer tissue and cell lines compared to normal human lung tissues. Overexpression of miR-142-5p resulted in decreased expression of PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha) at both mRNA and protein levels. We found that miR-142-5p overexpression markedly suppressed cell proliferation in vitro and in vivo. Conversely, inhibition of miR-142-5p promoted lung cancer growth. Mechanistic studies showed that PIK3CA was a potential target of miR-142-5p and it mediated reduction of PIK3CA resulting in suppression of PI3K/Akt pathway.

CONCLUSIONS

Our results demonstrate that miR-142-5p functions as a growth suppressive miRNA and plays an important role in inhibiting the tumorigenesis through targeting PIK3CA in non-small cell lung cancer.

Mitochondria-associated microRNAs in rat hippocampus following traumatic brain injury

Traumatic brain injury (TBI) is a major cause of death and disability. However, the molecular events contributing to the pathogenesis are not well understood. Mitochondria serve as the powerhouse of cells, respond to cellular demands and stressors, and play an essential role in cell signaling, differentiation, and survival. There is clear evidence of compromised mitochondrial function following TBI; however, the underlying mechanisms and consequences are not clear. MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression post-transcriptionally, and function as important mediators of neuronal development, synaptic plasticity, and neurodegeneration. Several miRNAs show altered expression following TBI; however, the relevance of mitochondria in these pathways is unknown. Here, we present evidence supporting the association of miRNA with hippocampal mitochondria, as well as changes in mitochondria-associated miRNA expression following a controlled cortical impact (CCI) injury in rats. Specifically, we found that the miRNA processing proteins Argonaute (AGO) and Dicer are present in mitochondria fractions from uninjured rat hippocampus, and immunoprecipitation of AGO associated miRNA from mitochondria suggests the presence of functional RNA-induced silencing complexes. Interestingly, RT-qPCR miRNA array studies revealed that a subset of miRNA is enriched in mitochondria relative to cytoplasm. At 12h following CCI, several miRNAs are significantly altered in hippocampal mitochondria and cytoplasm. In addition, levels of miR-155 and miR-223, both of which play a role in inflammatory processes, are significantly elevated in both cytoplasm and mitochondria. We propose that mitochondria-associated miRNAs may play an important role in regulating the response to TBI.