miR-365 promotes cutaneous squamous cell carcinoma (CSCC) through targeting nuclear factor I/B (NFIB)

MicroRNA-346 functions as an oncogene in cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (cSCC) is an epidermal keratinocyte-derived skin tumor, which is the second most common skin cancer in the general population. Recently, studies showed that microRNAs (miRNAs) played an important role in the development of cancer. In our study, we showed that the expression of SRCIN1 was lower in cSCC tissues than in the matched normal tissues. Moreover, there was significant inversed correlation between miR-346 and SRCIN1 in cSCC tissues. The luciferase reporter assay data showed that miR-346 can target the SRCIN1 message via the 3'-untranslated region (UTR) of SRCIN1. Overexpression of miR-346 inhibited the messenger RNA (mRNA) and protein expression of SRCIN1 in the A431 cells. In addition, ectopic expression of miR-346 promoted the A431 cell proliferation and migration. Meanwhile, SRCIN1 overexpression inhibited the A431 cell proliferation and migration. Rescue experiment has showed that SRCIN1 overexpression reduced the miR-346-induced A431 cell proliferation and migration. Herein, this study may provide miR-346 as a new therapeutic target for cSCC.

Decreased expression of microRNA-20a promotes tumor progression and predicts poor prognosis of cutaneous squamous cell carcinoma

BACKGROUND

MicroRNA-20a (miRNA-20a or miR-20a) plays a key role in tumorigenesis and progression. But the prognostic value of miR-20a in cutaneous squamous cell carcinoma (CSCC) remains unclear. The aim of this study was to identify the association of miR-20a and the prognosis of CSCC patients.

METHODS

The miR-20a expression was detected using quantitative real-time polymerase chain reaction (qRT-PCR) in 152 CSCC tissues and matched adjacent normal tissues. Kaplan-Meier and Cox regression analysis were utilized to determine the association of miR-20a with overall survival as well as the prognosis of CSCC patients.

RESULTS

The expression of miR-20a was lower in CSCC tissues compared with adjacent normal tissues (P=0.000). Moreover, the expression of miR-20a was closely correlated with TNM stage (P=0.013). Kaplan-Meier analysis showed that patients with low miR-20a expression had significantly poorer overall survival than those with high miR-20a expression (P<0.05). Multivariate analysis revealed that miR-20a expression (P=0.001, HR=3.262, 95% CI: 1.635-6.520) could influence the prognosis and might be an independent prognostic predictor in CSCC.

CONCLUSIONS

Our results indicated that low miR-20a expression was associated with tumor stage of CSCC and suggested that miR-20a expression would be a novel biomarker for predicting clinical outcomes in CSCC patients. The inhibition of miR-20a might even become a new therapeutic method for the treatment of CSCC.

STMN1 overexpression correlates with biological behavior in human cutaneous squamous cell carcinoma

Stathmin 1 (STMN1) is an important molecule in regulating cellular microtubule dynamics and promoting microtubule depolymerization in interphase and late mitosis. Evidences showed that STMN1 was up-regulated in many cancers, but there was no report about the roles of STMN1 in human cutaneous squamous cell carcinoma (cSCC). Here, we confirmed significant upregulation of STMN1 in cSCC tissues and cell lines compared with non-tumor counterparts. STMN1 upregulation was associated with the proliferation, migration, invasion and apoptosis of cSCC cells. The results suggested that STMN1 may play an important role in the development and tumor progression of cSCC.

A Genome-Wide Scan Identifies Variants in NFIB Associated with Metastasis in Patients with Osteosarcoma

Metastasis is the leading cause of death in patients with osteosarcoma, the most common pediatric bone malignancy. We conducted a multistage genome-wide association study of osteosarcoma metastasis at diagnosis in 935 osteosarcoma patients to determine whether germline genetic variation contributes to risk of metastasis. We identified an SNP, rs7034162, in NFIB significantly associated with metastasis in European osteosarcoma cases, as well as in cases of African and Brazilian ancestry (meta-analysis of all cases: P = 1.2 × 10(-9); OR, 2.43; 95% confidence interval, 1.83-3.24). The risk allele was significantly associated with lowered NFIB expression, which led to increased osteosarcoma cell migration, proliferation, and colony formation. In addition, a transposon screen in mice identified a significant proportion of osteosarcomas harboring inactivating insertions in Nfib and with lowered NFIB expression. These data suggest that germline genetic variation at rs7034162 is important in osteosarcoma metastasis and that NFIB is an osteosarcoma metastasis susceptibility gene.

SIGNIFICANCE

Metastasis at diagnosis in osteosarcoma is the leading cause of death in these patients. Here we show data that are supportive for the NFIB locus as associated with metastatic potential in osteosarcoma.

microRNA-365-targeted nuclear factor I/B transcriptionally represses cyclin-dependent kinase 6 and 4 to inhibit the progression of cutaneous squamous cell carcinoma

Cyclin-dependent kinases are either post-transcriptionally regulated by interacting with cyclins and cyclin-dependent kinase inhibitors or are transcriptionally regulated by transcription factors, but the latter mechanism has not been extensively investigated. Dysregulated transcription factors resulting from aberrantly expressed microRNAs play critical roles in tumor development and progression. Our previous work identified miR-365 as an oncogenic microRNA that promotes the development of cutaneous squamous cell carcinoma via repression of cyclin-dependent kinase 6, while miR-365 also targets nuclear factor I/B. However, the underlying mechanism(s) of the interaction between nuclear factor I/B and cyclin-dependent kinase 6 are unclear. In this work, we demonstrate that miR-365-regulated nuclear factor I/B transcriptionally inhibits cyclin-dependent kinases 6 and 4 by binding to their promoter regions. In vivo and in vitro experiments demonstrate that the loss of nuclear factor I/B after miR-365 expression or treatment with small interfering RNAs results in the upregulation of cyclin-dependent kinases 6 and 4. This upregulation, in turn, enhances the phosphorylation of retinoblastoma protein and tumor progression. Characterizing this transcriptional repression of cyclin-dependent kinases 6 and 4 by nuclear factor I/B contributes to the understanding of the transcriptional regulation of cyclin-dependent kinases by transcription factors and also facilitates the development of new therapeutic regimens to improve the clinical treatment of cutaneous squamous cell carcinoma.

Identification of miR-199a-5p target genes in the skin keratinocyte and their expression in cutaneous squamous cell carcinoma

BACKGROUND

MicroRNAs (miRNAs) are small non-coding RNA molecules that mediate the biological cellular processes via regulation of target genes through translational repression or mRNA degradation. Among various miRNAs, miRNA-199a (miR-199a) has been known to be involved in cancer development and progression, protection of cardiomyocyte, and skeletal formation.

OBJECTIVE

Although miR-199a-5p was studied in various cell types, the role of miR-199a-5p and its target genes in skin keratinocyte have not been documented. In this study, we identified target genes of miR-199a-5p in skin keratinocyte.

METHODS

In order to identify the target of miR-199a-5p in keratinocyte, microarray analysis was performed. The relative expression of candidate target genes was investigated using quantitative RT-PCR and western blot analysis. To determine whether their expression was directly regulated by miR-199a-5p, luciferase reporter assay was performed. In order to investigate expression of target genes in cutaneous squamous cell carcinoma, immunohistochemistry was performed.

RESULTS

We identified new target genes, Bcam, Fzd6, and Wnt7a, as well as previously known targets, Ddr1 and Podxl. We found that their expressions were directly regulated by miR-199a-5p in the skin keratinocyte using in vitro study and observed that expression of miR-199a-5p was inversely correlated with those of BCAM, FZD6 and DDR1 in the cSCC. In addition, overexpression of miR-199a-5p resulted in inhibition of the migratory capability of the skin keratinocyte.

CONCLUSION

These results suggested that miR-199a-5p plays a role in pathogenesis of cSCC via inhibition of invasiveness through regulation of BCAM, FZD6 and DDR1 expression.

MicroRNA transcriptome analysis identifies miR-365 as a novel negative regulator of cell proliferation in Zmpste24-deficient mouse embryonic fibroblasts

Zmpste24 is a metalloproteinase responsible for the posttranslational processing and cleavage of prelamin A into mature laminA. Zmpste24(-/-) mice display a range of progeroid phenotypes overlapping with mice expressing progerin, an altered version of lamin A associated with Hutchinson-Gilford progeria syndrome (HGPS). Increasing evidence has demonstrated that miRNAs contribute to the regulation of normal aging process, but their roles in progeroid disorders remain poorly understood. Here we report the miRNA transcriptomes of mouse embryonic fibroblasts (MEFs) established from wild type (WT) and Zmpste24(-/-) progeroid mice using a massively parallel sequencing technology. With data from 19.5 × 10(6) reads from WT MEFs and 16.5 × 10(6) reads from Zmpste24(-/-) MEFs, we discovered a total of 306 known miRNAs expressed in MEFs with a wide dynamic range of read counts ranging from 10 to over 1 million. A total of 8 miRNAs were found to be significantly down-regulated, with only 2 miRNAs upregulated, in Zmpste24(-/-) MEFs as compared to WT MEFs. Functional studies revealed that miR-365, a significantly down-regulated miRNA in Zmpste24(-/-) MEFs, modulates cellular growth phenotypes in MEFs. Overexpression of miR-365 in Zmpste24(-/-) MEFs increased cellular proliferation and decreased the percentage of SA-β-gal-positive cells, while inhibition of miR-365 function led to an increase of SA-β-gal-positive cells in WT MEFs. Furthermore, we identified Rasd1, a member of the Ras superfamily of small GTPases, as a functional target of miR-365. While expression of miR-365 suppressed Rasd1 3' UTR luciferase-reporter activity, this effect was lost with mutations in the putative 3' UTR target-site. Consistently, expression levels of miR-365 were found to inversely correlate with endogenous Rasd1 levels. These findings suggest that miR-365 is down-regulated in Zmpste24(-/-) MEFs and acts as a novel negative regulator of Rasd1. Our comprehensive miRNA data provide a resource to study gene regulatory networks in MEFs.

Associations of deregulation of mir-365 and its target mRNA TTF-1 and survival in patients with NSCLC

microRNA (mir)-365 exerts tumor suppressor function by targeting thyroid transcription factor-1 (TTF-1) in lung cancer cells. The purpose of the present study was to assess mir-365 and its target mRNA TTF-1 in lung cancer and their correlations with patients' survival. Quantitative real-time PCR was used to examine the expression levels of mir-365 and TTF-1 in tumor tissue and its adjacent noncancerous tissue of 126 patients with non-small cell lung cancer (NSCLC). Our results showed that mir-365 was significantly decreased in tumor tissue than that in normal tissue (P=0.006), however, TTF-1 was significantly increased in tumor tissue than in normal tissue (P<0.001). Besides, significant correlations between decreased mir-365 and advanced tumor-node-metastasis (TNM) stage (P=0.001) and regional lymph node involvement (P=0.037) was observed. The similar result was also found between increased TTF-1 and TNM stage (P=0.003). Furthermore, mir-365 downregulation or TTF-1 upregulation were associated with poor outcome of patients than mir-365 upregulation or TTF-1 downregulation (for mir-365: P<0.001; for TTF-1: P=0.002). Of note, combination of decreased mir-365 and increased TTF-1 had worst overall survival (P<0.001). In conclusion, aberrant expression of mir-365/TTF-1 may be involved in the tumor development in patients with NSCLC. Moreover, mir-365 and TTF-1 could jointly predict the prognosis of patients and their combination may serve as a biomarker to predict risk of poor survival in NSCLC patients. Mir-365/TTF-1 might serve as a potential therapeutic target for clinical treatment of NSCLC.

Prognostic significance and anti-proliferation effect of microRNA-365 in hepatocellular carcinoma

MircroRNA functions as tumor suppressor or promoter in hepatocellular carcinoma (HCC). Researchers have found that miR-365 expression was lower in HCC tissues compared with that in adjacent normal tissues. However, its prognostic significance and anti-proliferation effect in HCC remain to be clarified. In this study, we firstly found that miR-365 expression was lower in HCC tissues compared with that in adjacent normal tissues. Then, we analyzed miR-365 expression level and its clinicopathological and prognostic significance. Finally, overexpression of miR-365 inhibits HCC cell proliferation and migration in vitro. Our findings suggest that miR-365 expression was an independent poor prognostic factor for HCC patient overall survival and suppressed tumor cell growth. Therefore, miR-365 may serve as a valuable prognostic marker and promising target for HCC.

Pannexin‑1 silencing inhibits the proliferation of U87‑MG cells

Pannexin‑1 (Panx‑1) is abundantly expressed in vertebrates and has been shown to assemble into high‑conductance single‑membrane channels, which are permeable to large molecules and regulate cellular function. However, the association between Panx‑1 and astrocyte proliferation is poorly understood. This study provides evidence for a difference in cell proliferation between wild‑type and Panx‑1‑knockdown cells. Proliferation of the U87‑MG malignant glioma cell line was reduced following transfection with Panx‑1‑short interfering RNA. In addition, treatment with the Panx‑1 activator, adenosine triphosphate, significantly reduced cell proliferation at 48 h in Panx‑1‑knockdown cells compared with wild type cells. In conclusion, on the basis of the present findings, Panx‑1 is likely to be important in the regulation of U87‑MG cell proliferation. This provides further support for the hypothesis that there is a correlation between Panx‑1 expression and U87‑MG cell proliferation.