miR-184 promotes cell proliferation in tongue squamous cell carcinoma by targeting SOX7

miR-184 represses β-catenin and behaves as a skin tumor suppressor

miR-184-knockout mice display perturbed epidermal stem cell differentiation. However, the potential role of miR-184 in skin pathology is unclear. Here, we report that miR-184 controls epidermal stem cell dynamics and that miR-184 ablation enhances skin carcinogenesis in mice. In agreement, repression of miR-184 in human squamous cell carcinoma (SCC) enhances neoplastic hallmarks of human SCC cells in vitro and tumor development in vivo. Characterization of miR-184-regulatory network, suggests that miR-184 inhibits pro-oncogenic pathways, cell proliferation, and epithelial to mesenchymal transformation. Of note, depletion of miR-184 enhances the levels of β-catenin under homeostasis and following experimental skin carcinogenesis. Finally, the repression of β-catenin by miR-184, inhibits the neoplastic phenotype of SCC cells. Taken together, miR-184 behaves as an epidermal tumor suppressor, and may provide a potentially useful target for skin SCC therapy.

miR-532-3p inhibits the progression of tongue squamous cell carcinoma by targeting podoplanin

BACKGROUND

The association between miR-532-3p and tongue squamous cell carcinoma (TSCC) has been examined in the literature to improve the survival rate of patients with this tumor. However, further studies are needed to confirm the regulatory roles of this microRNA (miRNA) in TSCC. The objective of this study was to investigate the roles played by and the underlying mechanism used by the miR-532-3p/podoplanin (PDPN) axis in TSCC development.

METHODS

Western blotting and quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR) were performed to evaluate the PDPN expression level in TSCC tissues and cells. The proliferative, adhesive, and migratory capabilities of TSCC cells (CAL-27 and CTSC-3) were examined using cell counting kit-8 (CCK-8), cell adhesion, and wound-healing assays, respectively. The dual-luciferase reporter (DLR) assay was later conducted to confirm the relationship between miR-532-3p and PDPN.

RESULTS

The results indicated that PDPN expression was enriched in TSCC tissues and cells, and that the expression of PDPN was associated with some clinicopathological parameters of TSCC, including lymph node metastasis (P = 0.001), tumor-node-metastasis (TNM) staging (P = 0.010), and grading (P = 0.010). Further analysis also showed that PDPN knockdown inhibited the viability, adhesive ability, and migratory capacity of CAL-27 and CTSC-3 cells, effects that could be reversed by the application of a miR-532-3p inhibitor. Additionally, PDPN was found to be a direct target of miR-532-3p.

CONCLUSIONS

This research suggested that by targeting PDPN, miR-532-3p could inhibit cell proliferation viability, adhesion, and migration in TSCC. Findings also revealed that the miR-532-3p/PDPN axis might provide more insights into the prognosis and treatment of TSCC.

miR-184 delays cell proliferation, migration and invasion in prostate cancer by directly suppressing DLX1

A number of previous studies have reported that dysregulated miR-184 expression is associated with the development of cancer. The aim of the present study was to investigate the role of miR-184 in prostate cancer (PC) and the mechanism underlying its effects. Data from human tumor tissue samples were collected from The CEancer Genome Atlas to determine the expression levels of miR-184 and DLX1. The miR-184 mimic and pcDNA3.1-DLX1 plasmid were utilized to induce overexpression of miR-184 and DLX1 in Du145 cells, respectively. Cell Counting Kit-8, wound healing and Transwell assays were performed to examine the effects of miR-184 on the aggressiveness of PC cells. Dual-luciferase reporter gene assay was used to investigate the association between miR-184 and DLX1, and reverse transcription-quantitative PCR and western blot analyses were utilized to determine the mRNA and protein levels. miR-184 expression was found to be downregulated whereas DLX1 was upregulated in PC tissues compared with normal prostate tissues. Cell propagation, migration and invasion were all inhibited by miR-184 upregulation in Du145 cells. Dual luciferase reporter assay confirmed the association between miR-184 and DLX1. The inhibitory effect of miR-184 mimic on cell behaviors was reversed by upregulation of DLX1. These findings suggest that miR-184 plays a beneficial role in suppressing the tumorigenesis of PC by directly targeting DLX1, and it may represent a potential therapeutic strategy for PC.

miR-146b Functions as an Oncogene in Oral Squamous Cell Carcinoma by Targeting HBP1

Oral squamous cell carcinoma (OSCC) represents more than 90% of all oral cancer and is the most common oral threat around the world. In this study, we examined the roles of miR-146b in OSCC cells. The miR-146b expression in OSCC tissues and cell lines was evaluated by quantitative real-time PCR (qRT-PCR). MTT assay was used to investigate the impact of miR-146b on the growth of OSCC cells in vitro. Transwell assay was utilized to analyze the effect of miR-146b on the migration and invasion of OSCC cells. Target prediction and luciferase assay were employed to demonstrate the interaction between miR-146b and HMG-Box Transcription Factor 1 (HBP1). Western blot was carried out to investigate the protein expressions of HBP1 related genes. miR-146b expression was significantly higher in OSCC tissues and cells compared with paired normal tissues and normal oral keratinocyte cells. Inhibition of miR-146b decreased cell proliferation, migration, and invasion of OSCC cells. Further studies found that HBP1 was a direct target of miR-146b. Co-inhibition of HBP1 reversed the suppressive impact of miR-146b inhibition on OSCC cell proliferation, migration, and invasion. In conclusion-ourresults reveal that miR-146b potentially regulates the proliferation, migration, and invasion of OSCC cells through binding and downregulating HBP1 expression in OSCC cells.

JNK pathway plays a key role in the immune system of the pea aphid and is regulated by microRNA-184

Different from holometabolous insects, the hemipteran species such as pea aphid Acyrthosiphon pisum exhibit reduced immune responses with the absence of the genes coding for antimicrobial peptide (AMP), immune deficiency (IMD), peptidoglycan recognition proteins (PGRPs), and other immune-related molecules. Prior studies have proved that phenoloxidase (PO)-mediated melanization, hemocyte-mediated phagocytosis, and reactive oxygen species (ROS) participate in pea aphid defense against bacterial infection. Also, the conserved signaling, Jun N-terminal kinase (JNK) pathway, has been suggested to be involved in pea aphid immune defense. However, the precise role of the JNK signaling, its interplay with other immune responses and its regulation in pea aphid are largely unknown. In this study, using in vitro biochemical assays and in vivo bioassays, we demonstrated that the JNK pathway regulated hemolymph PO activity, hydrogen peroxide concentration and hemocyte phagocytosis in bacteria infected pea aphids, suggesting that the JNK pathway plays a central role in regulating immune responses in pea aphid. We further revealed the JNK pathway is regulated by microRNA-184 in response to bacterial infection. It is possible that in common the JNK pathway plays a key role in immune system of hemipteran insects and microRNA-184 regulates the JNK pathway in animals.

SOX7 is involved in polyphyllin D-induced G0/G1 cell cycle arrest through down-regulation of cyclin D1

The incidence of mortality of prostate cancer (PCa) has been an uptrend in recent years. Our previous study showed that the sex-determining region Y-box 7 (SOX7) was low-expressed and served as a tumor suppressor in PCa cells. Here, we describe the effects of polyphyllin D (PD) on proliferation and cell cycle modifications of PCa cells, and whether SOX7 participates in this process. PC-3 cells were cultured in complete medium containing PD for 12, 24, and 48 h. MTT assay was used to investigate the cytotoxic effects of PD. Cell cycle progression was analyzed using propidium iodide (PI) staining, and protein levels were assayed by Western blot analysis. Our results showed low expression of SOX7 in PCa tissues/cells compared to their non-tumorous counterparts/RWPE-1 cells. Moreover, PD inhibited the proliferation of PC-3 cells in a dose- and time-dependent manner. PD induced G0/G1 cell cycle arrest, while co-treatment with short interfering RNA targeting SOX7 (siSOX7) had reversed this effect. PD downregulated SOX7, cyclin D1, cyclin-dependent kinase 4 (CDK4), and cyclin-dependent kinase 6 (CDK6) expressions in a dose-dependent manner, whereas co-treatment of siSOX7 and PD rescued the PD-inhibited cyclin D1 expression. However, no obvious changes were observed in CDK4 or CDK6 expression. These results indicate that SOX7 is involved in PD-induced PC-3 cell cycle arrest through down-regulation of cyclin D1.

Functional Analysis of the 3' Untranslated Region of the Human GRIN1 Gene in Regulating Gene Expression in vitro

PURPOSE

Abnormal expression of the NR1 subunit of the N-methyl-d-aspartate (NMDA) receptor may potentially increase the susceptibility to neuropsychiatric diseases. The purpose of this study was to investigate the functional sequence of the 3'UTR of the human GRIN1 gene, which encodes the GluN1 receptor to determine the effect on the expression of GluN1 receptor.

METHODS

We transferred seven recombinant pmirGLO recombinant vectors containing the 3'UTR truncated fragment of the GRIN1 gene into HEK-293, SK-N-SH, and U87 cell lines and compared the relative fluorescence intensity of adjacent length fragments. The TargetScan database was used to predict miRNAs. Then, miRNA mimics/inhibitors were co-transfected into the three cell lines with the 3'UTR of GRIN1 (pmirGLO - GRIN1), to investigate their influence on GRIN1 gene expression.

RESULTS

Compared with the pmirGLo-Basic vector, the relative fluorescence intensity of the complete GRIN1 gene 3'UTR recombinant sequence -27 bp - +1284 bp (the next base of the stop codon is +1) was significantly decreased in all three cell lines. The relative fluorescence intensities were significantly different between -27 bp - +294 bp and -27 bp - +497 bp regions, and between -27 bp - +708 bp and -27 bp - +907 bp regions. According to the prediction of the TargetScan database and analysis, miR-212-5p, miR-324-3p and miR-326 may bind to +295 bp - +497 bp, while miR-491-5p may bind to +798 bp - +907 bp. After co-transfection of miRNA mimic/inhibitor or mimic/inhibitor NC with a recombinant vector in the 3'UTR region of GRIN1 gene, we found that has-miR-491-5p inhibited GRIN1 expression significantly in all three cell lines, while has-miR-326 inhibitor upregulated GRIN1 expression in HEK-293 and U87 cells.

CONCLUSION

miR-491-5p may bind to the 3'UTR of the GRIN1 gene (+799 bp - +805 bp, the next base of the stop codon is +1) and down-regulate gene expression in HEK-293, SK-N-SH, and U87 cell lines, which implicates a potential role of miR-491-5p in central nervous system diseases.