MiR-195 and miR-497 suppress tumorigenesis in lung cancer by inhibiting SMURF2-induced TGF-β receptor I ubiquitination

Deletion of 17p in cancers: Guilt by (p53) association

Monoallelic deletion of the short arm of chromosome 17 (del17p) is a recurrent abnormality in cancers with poor outcomes. Best studied in relation to haematological malignancies, associated functional outcomes are attributed mainly to loss and/or dysfunction of TP53, which is located at 17p13.1, but the wider impact of deletion of other genes located on 17p is poorly understood. 17p is one of the most gene-dense regions of the genome and includes tumour suppressor genes additional to TP53, genes essential for cell survival and proliferation, as well as small and long non-coding RNAs. In this review we utilise a data-driven approach to demarcate the extent of 17p deletion in multiple cancers and identify a common loss-of-function gene signature. We discuss how the resultant loss of heterozygosity (LOH) and haploinsufficiency may influence cell behaviour but also identify vulnerabilities that can potentially be exploited therapeutically. Finally, we highlight how emerging animal and isogenic cell line models of del17p can provide critical biological insights for cancer cell behaviour.

Curcumin inhibits the activity of ubiquitin ligase Smurf2 to promote NLRP3‑dependent pyroptosis in non‑small cell lung cancer cells

Non‑small cell lung cancer (NSCLC) is a malignant tumor of significant clinical relevance. Curcumin has been investigated for its potential anticancer properties, as it has been reported to act through multiple cancer‑related targets and pathways. The present study aimed to explore the effects of curcumin in NSCLC using both in vitro and in vivo models. NSCLC cell lines (specifically, A549 and NCI‑H1299 cells), and a mouse tumor model established through the subcutaneous injection of A549 cells, were utilized to evaluate the effects of curcumin intervention. The effects of treatment with curcumin on NOD‑like receptor pyrin domain‑containing 3 (NLRP3) ubiquitination, cell pyroptosis and pyroptosis‑associated factors were also evaluated. In addition, Smad ubiquitination regulatory factor 2 (Smurf2) was analyzed via a series of knockdown and overexpression experiments, both in vitro and in vivo, aimed at investigating its association with curcumin and NLRP3. The results obtained from these experiments showed that curcumin inhibited NSCLC cell growth, promoted pyroptosis and reduced the level of NLRP3 ubiquitination. NLRP3 knockdown reversed the curcumin‑induced increase in pyroptosis‑associated factors both in vitro and in vivo. Additionally, Smurf2 interacted with NLRP3 and alterations in Smurf2 expression levels influenced NLRP3 ubiquitination and cell pyroptosis. Moreover, molecular docking analysis demonstrated that curcumin could bind directly to Smurf2, which subsequently led to an inhibition of Smurf2 activity. Knockdown of Smurf2 enhanced curcumin's ability to stabilize NLRP3 and to promote pyroptosis, whereas Smurf2 overexpression negated these effects. In the in vivo animal model, curcumin treatment led to reduced tumor volumes and weights, in addition to a decreased expression level of Ki67 and increased expression levels of NLRP3 and pyroptosis‑associated factors. Similarly, these effects were enhanced or reversed by Smurf2 knockdown or overexpression, respectively. In conclusion, the findings of the present study showed that curcumin inhibited Smurf2 activity, thereby promoting NLRP3‑dependent pyroptosis in NSCLC cells. In addition, these findings have provided mechanistic insights into the role of curcumin in NSCLC, opening an avenue for its potential therapeutic application.

Epigenetic regulation of TGF-β pathway and its role in radiation response

PURPOSE

Transforming growth factor (TGF-β) plays a dual role in tumor progression as well as a pivotal role in radiation response. TGF-β-related epigenetic regulations, including DNA methylation, histone modifications (including methylation, acetylation, phosphorylation, ubiquitination), chromatin remodeling and non-coding RNA regulation, have been found to affect the occurrence and development of tumors as well as their radiation response in multiple dimensions. Due to the significance of radiotherapy in tumor treatment and the essential roles of TGF-β signaling in radiation response, it is important to better understand the role of epigenetic regulation mechanisms mediated by TGF-β signaling pathways in radiation-induced targeted and non-targeted effects.

CONCLUSIONS

By revealing the epigenetic mechanism related to TGF-β-mediated radiation response, summarizing the existing relevant adjuvant strategies for radiotherapy based on TGF-β signaling, and discovering potential therapeutic targets, we hope to provide a new perspective for improving clinical treatment.

miR-195b is required for proper cellular homeostasis in the elderly

Over the last decade we have witnessed an increasing number of studies revealing the functional role of non-coding RNAs in a multitude of biological processes, including cellular homeostasis, proliferation and differentiation. Impaired expression of non-coding RNAs can cause distinct pathological conditions, including herein those affecting the gastrointestinal and cardiorespiratory systems, respectively. miR-15/miR-16/miR-195 family members have been broadly implicated in multiple biological processes, including regulation of cell proliferation, apoptosis and metabolism within distinct tissues, such as heart, liver and lungs. While the functional contribution of miR-195a has been reported in multiple biological contexts, the role of miR-195b remains unexplored. In this study we dissected the functional role of miR-195b by generating CRISPR-Cas9 gene edited miR-195b deficient mice. Our results demonstrate that miR-195b is dispensable for embryonic development. miR-195b-/- mice are fertile and displayed no gross anatomical and/or morphological defects. Mechanistically, cell cycle regulation, metabolism and oxidative stress markers are distinctly impaired in the heart, liver and lungs of aged mice, a condition that is not overtly observed at midlife. The lack of overt functional disarray during embryonic development and early adulthood might be due to temporal and tissue-specific compensatory mechanisms driven by selective upregulation miR-15/miR-16/miR-195 family members. Overall, our data demonstrated that miR-195b is dispensable for embryonic development and adulthood but is required for cellular homeostasis in the elderly.

Current landscape of miRNAs and TGF-β signaling in lung cancer progression and therapeutic targets

Lung cancer (LC) is the primary reason for cancer-associated fatalities globally. Due to both tumor-suppressing and tumor-promoting activities, the TGF-β family of growth factors is extremely essential to tumorigenesis. A non-coding single-stranded short RNA called microRNA (miRNA), which is made up of about 22 nt and is encoded by endogenous genes, can control normal and pathological pathways in various kinds of cancer, including LC. Recent research demonstrated that the TGF-β signaling directly can affect the synthesis of miRNAs through suppressor of mothers against decapentaplegic (SMAD)-dependent activity or other unidentified pathways, which could generate allostatic feedback as a result of TGF-β signaling stimulation and ultimately affect the destiny of cancer tissues. In this review, we emphasize the critical functions of miRNAs in lung cancer progression and, more critically, how they affect the TGF-β signaling pathway, and explore the role of both the TGF-β signaling pathway and miRNAs as potential therapeutic targets for improving the treatments of LC patients.

The roles of protein ubiquitination in tumorigenesis and targeted drug discovery in lung cancer

The malignant lung cancer has a high morbidity rate and very poor 5-year survival rate. About 80% - 90% of protein degradation in human cells is occurred through the ubiquitination enzyme pathway. Ubiquitin ligase (E3) with high specificity plays a crucial role in the ubiquitination process of the target protein, which usually occurs at a lysine residue in a substrate protein. Different ubiquitination forms have different effects on the target proteins. Multiple short chains of ubiquitination residues modify substrate proteins, which are favorable signals for protein degradation. The dynamic balance adapted to physiological needs between ubiquitination and deubiquitination of intracellular proteins is beneficial to the health of the organism. Ubiquitination of proteins has an impact on many biological pathways, and imbalances in these pathways lead to diseases including lung cancer. Ubiquitination of tumor suppressor protein factors or deubiquitination of tumor carcinogen protein factors often lead to the progression of lung cancer. Ubiquitin proteasome system (UPS) is a treasure house for research and development of new cancer drugs for lung cancer, especially targeting proteasome and E3s. The ubiquitination and degradation of oncogene proteins with precise targeting may provide a bright prospect for drug development in lung cancer; Especially proteolytic targeted chimerism (PROTAC)-induced protein degradation technology will offer a new strategy in the discovery and development of new drugs for lung cancer.

Unraveling the Complex Web of Mechanistic Regulation of Versatile NEDD4 Family by Non-Coding RNAs in Carcinogenesis and Metastasis: From Cell Culture Studies to Animal Models

Discoveries related to an intriguing feature of ubiquitination have prompted a detailed analysis of the ubiquitination patterns in malignant cells. How the "ubiquitinome" is reshaped during multistage carcinogenesis has garnered significant attention. Seminal studies related to the structural and functional characterization of NEDD4 (Neuronal precursor cell-expressed developmentally downregulated-4) have consolidated our understanding at a new level of maturity. Additionally, regulatory roles of non-coding RNAs have further complicated the complex interplay between non-coding RNAs and the members of NEDD4 family. These mechanisms range from the miRNA-mediated targeting of NEDD4 family members to the regulation of transcriptional factors for a broader range of non-coding RNAs. Additionally, the NEDD4-mediated degradation of different proteins is modulated by lncRNAs and circRNAs. The miRNA-mediated targeting of NEDD4 family members is also regulated by circRNAs. Tremendous advancements have been made in the identification of different substrates of NEDD4 family and in the comprehensive analysis of the molecular mechanisms by which various members of NEDD4 family catalyze the ubiquitination of substrates. In this review, we have attempted to summarize the multifunctional roles of the NEDD4 family in cancer biology, and how different non-coding RNAs modulate these NEDD4 family members in the regulation of cancer. Future molecular studies should focus on the investigation of a broader drug design space and expand the scope of accessible targets for the inhibition/prevention of metastasis.

NEDD4 E3 ubiquitin ligases: promising biomarkers and therapeutic targets for cancer

Accumulating evidence has demonstrated that NEDD4 E3 ubiquitin ligase family plays a pivotal oncogenic role in a variety of malignancies via mediating ubiquitin dependent degradation processes. Moreover, aberrant expression of NEDD4 E3 ubiquitin ligases is often indicative of cancer progression and correlated with poor prognosis. In this review, we are going to address association of expression of NEDD4 E3 ubiquitin ligases with cancers, the signaling pathways and the molecular mechanisms by which the NEDD4 E3 ubiquitin ligases regulate oncogenesis and progression, and the therapies targeting the NEDD4 E3 ubiquitin ligases. This review provides the systematic and comprehensive summary of the latest research status of E3 ubiquitin ligases in the NEDD4 subfamily, and proposes that NEDD4 family E3 ubiquitin ligases are promising anti-cancer drug targets, aiming to provide research direction for clinical targeting of NEDD4 E3 ubiquitin ligase therapy.

Extracellular Vesicle-Packaged miR-195-5p Sensitizes Melanoma to Targeted Therapy with Kinase Inhibitors

Management of advanced melanoma remains challenging, with most BRAF (B-Raf proto-oncogene, serine/threonine kinase)-mutated metastatic patients relapsing within a few months upon MAPK inhibitors treatment. Modulation of tumor-derived extracellular vesicle (EVs) cargo with enrichment of antitumoral molecules is a promising strategy to impair tumor progression and increase treatment response. Herein, we report that restored expression of miR-195-5p, down-regulated in melanoma favoring drug resistance, increases the release of EVs enriched in the tumor suppressor miRNAs, miR-195-5p, miR-152-3p, and miR-202-3p. Incorporating these EVs by bystander tumor cells resulted in decreased proliferation and viability, accompanied by a reduction in CCND1 and YAP1 mRNA levels. Upon treatment with MAPK inhibitors, miR-195 EVs significantly decreased BCL2-L1 protein levels and increased cell death ratio and treatment efficacy. Additionally, EVs exogenously loaded with miR-195-5p by electroporation reduced tumor volume in vivo and impaired engraftment and growth of xenografts implanted with melanoma cells exposed to MAPK inhibitors. Our study shows that miR-195-5p antitumoral activity can be spread to bystander cells through EVs, improving melanoma response to targeted therapy and revealing a promising EV-based strategy to increase clinical response in patients harboring BRAF mutations.

MIR497HG-Derived miR-195 and miR-497 Mediate Tamoxifen Resistance via PI3K/AKT Signaling in Breast Cancer

Tamoxifen is commonly used for the treatment of patients with estrogen receptor-positive (ER+) breast cancer, but the acquired resistance to tamoxifen presents a critical challenge of breast cancer therapeutics. Recently, long noncoding RNA MIR497HG and its embedded miR-497 and miR-195 are proved to play significant roles in many types of human cancers, but their roles in tamoxifen-resistant breast cancer remain unknown. The results indicate that MIR497HG deficiency induces breast cancer progression and tamoxifen resistance by inducing downregulation of miR-497/195. miR-497/195 coordinately represses five positive PI3K-AKT regulators (MAP2K1, AKT3, BCL2, RAF1, and CCND1), resulting in inhibition of PI3K-AKT signaling, and PI3K-AKT inhibition in tamoxifen-resistant cells restored tamoxifen responsiveness. Furthermore, ER α binds the MIR497HG promoter to activate its transcription in an estrogen-dependent manner. ZEB1 interacts with HDAC1/2 and DNMT3B at the MIR497HG promoter, resulting in promoter hypermethylation and histone deacetylation. The findings reveal that ZEB1-induced MIR497HG depletion contributes to breast cancer progression and tamoxifen resistance through PI3K-AKT signaling. MIR497HG can be used as a biomarker for predicting tamoxifen sensitivity in patients with ER+ breast cancer.

Exosomal transfer of miR-195-5p restrains lung adenocarcinoma progression

Exosome is an important way for tumor cells to communicate with other cells and plays an important role in tumor progression. Previous studies revealed that miR-195-5p acts as a tumor suppressor in lung cancer. However, the role and molecular mechanism of exosomal transferred miR-195-5p in lung adenocarcinoma (LAC) remains unknown. Here, we found that miR-195-5p expression in circulating exosomes of LAC patients was lower than that of healthy controls. Meanwhile, the expression of exosomal miR-195-5p from normal bronchial epithelial cell line BEAS-2B cells was significantly higher than that of lung cancer cell lines. The exosome labeling assay confirmed that BEAS-2B cells-derived exosomes could be captured by lung cancer cells. Furthermore, exosomal miR-195-5p derived from BEAS-2B cells remarkably inhibited the proliferation, migration, invasion of lung cancer cells, and tumor growth in vivo. In addition, exosomal miR-195-5p from BEAS-2B cells also suppressed the tube-forming ability of vascular endothelial cells. Moreover, we verified that miR-195-5p decreased apelin (APLN) expression to inactivate the Wnt signaling pathway, thereby inhibiting tumor invasiveness and angiogenesis. In conclusion, our research shows that exosomal miR-195-5p from normal bronchial epithelial cells hinders the progression of LAC, suggesting that regulation of exosomal miR-195-5p provides a novel strategy for LAC treatment.

The significance of the crosstalk between ubiquitination or deubiquitination and ncRNAs in non-small cell lung cancer

Lung cancer (LC) remains the leading cause of cancer-related deaths worldwide, with extremely high morbidity and mortality rates. Non-small cell lung cancer (NSCLC) is the most critical type of LC. It seriously threatens the life and health of patients because of its early metastasis, late clinical symptoms, limited early screening methods, and poor treatment outcomes. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), participate in cell proliferation, metastasis, and chemoresistance. Several previous studies have proven that ncRNAs are vital regulators of tumorigenesis. Ubiquitination plays the most crucial role in protein post-translational modification (PTM). Deubiquitination and ubiquitination form a homeostasis. In summary, ubiquitination and deubiquitination play essential roles in mediating the degradation or overexpression of a range of crucial proteins in various cancers. A growing number of researchers have found that interactions between ncRNAs and ubiquitination (or deubiquitination) play a crucial role in NSCLC. This review presents several typical examples of the important effects of ncRNAs and ubiquitination (or deubiquitination) in NSCLC, aiming to provide more creative ideas for exploring the diagnosis and treatment of NSCLC.

The Importance of the Immune System and Molecular Cell Signaling Pathways in the Pathogenesis and Progression of Lung Cancer

Lung cancer is a disease that in recent years has become one of the greatest threats to modern society. Every year there are more and more new cases and the percentage of deaths caused by this type of cancer increases. Despite many studies, scientists are still looking for answers regarding the mechanisms of lung cancer development and progression, with particular emphasis on the role of the immune system. The aim of this literature review was to present the importance of disorders of the immune system and the accompanying changes at the level of cell signaling in the pathogenesis of lung cancer. The collected results showed that in the process of immunopathogenesis of almost all subtypes of lung cancer, changes in the tumor microenvironment, deregulation of immune checkpoints and abnormalities in cell signaling pathways are involved, which contribute to the multistage and multifaceted carcinogenesis of this type of cancer. We, therefore, suggest that in future studies, researchers should focus on a detailed analysis of tumor microenvironmental immune checkpoints, and to validate their validity, perform genetic polymorphism analyses in a wide range of patients and healthy individuals to determine the genetic susceptibility to lung cancer development. In addition, further research related to the analysis of the tumor microenvironment; immune system disorders, with a particular emphasis on immunological checkpoints and genetic differences may contribute to the development of new personalized therapies that improve the prognosis of patients.

The miR-15b-Smurf2-HSP27 axis promotes pulmonary fibrosis

BACKGROUND

Heat shock protein 27 (HSP27) is overexpressed during pulmonary fibrosis (PF) and exacerbates PF; however, the upregulation of HSP27 during PF and the therapeutic strategy of HSP27 inhibition is not well elucidated.

METHODS

We have developed a mouse model simulating clinical stereotactic body radiotherapy (SBRT) with focal irradiation and validated the induction of RIPF. HSP25 (murine form of HSP27) transgenic (TG) and LLC1-derived orthotropic lung tumor models were also used. Lung tissues of patients with RIPF and idiopathic pulmonary fibrosis, and lung tissues from various fibrotic mouse models, as well as appropriated cell line systems were used. Public available gene expression datasets were used for therapeutic response rate analysis. A synthetic small molecule HSP27 inhibitor, J2 was also used.

RESULTS

HSP27 expression with its phosphorylated form (pHSP27) increased during PF. Decreased mRNA expression of SMAD-specific E3 ubiquitin-protein ligase 2 (Smurf2), which is involved in ubiquitin degradation of HSP27, was responsible for the increased expression of pHSP27. In addition, increased expression of miRNA15b was identified with decreased expression of Smurf2 mRNA in PF models. Inverse correlation between pHSP27 and Smurf2 was observed in the lung tissues of PF animals, an irradiated orthotropic lung cancer models, and PF tissues from patients. Moreover, a HSP27 inhibitor cross-linked with HSP27 protein to ameliorate PF, which was more effective when targeting the epithelial to mesenchymal transition (EMT) stage of PF.

CONCLUSIONS

Our findings identify upregulation mechanisms of HSP27 during PF and provide a therapeutic strategy for HSP27 inhibition for overcoming PF.

LIM and Cysteine-Rich Domains 1 Promotes Transforming Growth Factor β1–Induced Epithelial–Mesenchymal Transition in Human Kidney 2 Cells

Renal fibrosis is the major pathologic manifestation of chronic kidney disease (CKD). LIM and cysteine-rich domains 1 (LMCD1) is upregulated in the kidney tissue from patients with CKD and the transforming growth factor β1 (TGF-β1)-treated human renal tubular epithelial cell line human kidney 2 (HK-2) (Gene Expression Omnibus: GSE66494 and GSE23338). Previously, we have demonstrated that the knockdown of LMCD1 ameliorated renal fibrosis in mice by blocking the activation of the extracellular signal-regulated kinase pathway. In this study, we sought to further investigate whether LMCD1 affects TGF-β1-induced epithelial-mesenchymal transition (EMT) of kidney tubular epithelial cells and its potential role in the TGF-β1/Smad signaling pathway. First, we confirmed that LMCD1 expression was increased in the fibrotic kidneys of patients with CKD compared with that in normal kidneys and that LMCD1 was predominantly localized in the renal tubules. LMCD1 and mesenchymal markers were upregulated in obstructed kidney tissues of mice at 21 days after unilateral ureteral obstruction surgery compared with the tissues in sham mice. Next, we demonstrated that TGF-β1 significantly increased LMCD1 expression through Smad-mediated transcription in HK-2 cells in vitro. In turn, LMCD1 acted as a transcriptional coactivator of E2F transcription factor 1 to promote the transcription of TGF-β1. Moreover, TGF-β1 increased the interaction between LMCD1 and Smad ubiquitination regulatory factor 2 (Smurf2) and accelerated Smurf2-mediated LMCD1 degradation via the ubiquitination system. The knockdown of LMCD1 inhibited TGF-β1-induced EMT in both HK-2 cells and unilateral ureteral obstruction mice. Our results indicate a positive feedback loop between TGF-β1 and LMCD1 for EMT induction in HK-2 cells and that Smurf2 acts as a negative regulator in this process by accelerating LMCD1 degradation.

Inhibition of miR-497 Attenuates Oral Submucous Fibrosis by Inhibiting Myofibroblast Transdifferentiation in Buccal Mucosal Fibroblasts

PURPOSE

Oral submucous fibrosis (OSF) is a common chronic condition with poor prognosis, and existing therapies for OSF are limited in effectiveness. This study was designed to explore the role of miR-497 in arecoline (AR)-induced OSF.

MATERIALS AND METHODS

After miR-497 was silenced or overexpressed in buccal mucosa fibroblasts (BMFs), different concentrations of AR (5-200 μg/ml) were applied to incubate BMFs, and 50 μg/ml of AR was chosen for subsequent experiments. Thereafter, collagen gel contraction assay was used to detect the contractile capacity of BMFs. Transwell assay and wound healing assay were applied to detect migration and invasiveness of the cells. In addition, immunofluorescence staining, qRT-PCR and western blot were conducted to measure the expression of miR-497, collagen I and α-SMA, as well as the phosphorylation of Smad2 and Smad3.

RESULTS

After successful inhibition or overexpression of miR-497 in AR-induced BMFs, the results showed that miR- 497 inhibition suppressed the contractility, migration and invasiveness of AR-induced BMFs, whereas overexpression of miR-497 produced the opposite. In addition, miR-497 inhibition down-regulated the expression level of collagen I and α-SMA in AR-exposed BMFs. Furthermore, TGF-β1 expression, Smad2 and Smad3 phosphorylation were also repressed in AR-induced BMFs after miR-497 inhibition. Correspondingly, overexpression of miR-497 reversed the expression of the aforementioned proteins.

CONCLUSION

miR-497 inhibition may attenuate OSF by inhibiting myofibroblast transdifferentiation in BMFs via the TGF-β1/Smads signaling pathway, indicating that miR-497 might represent an underlying target for treating OSF.

MiRNAs in Lung Cancer: Diagnostic, Prognostic, and Therapeutic Potential

Lung cancer is the dominant emerging factor in cancer-related mortality around the globe. Therapeutic interventions for lung cancer are not up to par, mainly due to reoccurrence/relapse, chemoresistance, and late diagnosis. People are currently interested in miRNAs, which are small double-stranded (20–24 ribonucleotides) structures that regulate molecular targets (tumor suppressors, oncogenes) involved in tumorigeneses such as cell proliferation, apoptosis, metastasis, and angiogenesis via post-transcriptional regulation of mRNA. Many studies suggest the emerging role of miRNAs in lung cancer diagnostics, prognostics, and therapeutics. Therefore, it is necessary to intensely explore the miRNOME expression of lung tumors and the development of anti-cancer strategies. The current review focuses on the therapeutic, diagnostic, and prognostic potential of numerous miRNAs in lung cancer.

miR-150-5p inhibits nasopharyngeal cancer genesis by suppressing PYCR1

BACKGROUND

Nasopharyngeal cancer (NPC) is a rare cancer type with a low five-year survival rate. Dysregulation of PYCR1 and miR-150-5p has been involved in the development of various cancers. However, the molecular mechanism of the miR-150-5p-PYCR1 axis in NPC remains unclear.

METHODS

The expressions of miR-150-5p and PYCR1 in NPC tissues and cells were measured by RT-qPCR. The luciferase assay and RNA pull-down assay were used to confirm the interaction between miR-150-5p and PYCR1. The function of overexpression of miR-150-5p and PYCR1 were detected by cell viability, proliferation, migration and invasion in NPC C666-1 and SUNE-1 cells.

RESULTS

The miR-150-5p expression was reduced in NPC tissues and cells and negatively correlated with PYCR1 level. Upregulation of miR-150-5p conspicuously repressed cell growth. However, upregulation of PYCR1 significantly facilitated the development of NPC, which further suppressed NPC tumorigenesis by abolishing the effect of miR-150-5p.

CONCLUSIONS

We clarified that miR-150-5p attenuated NPC tumorigenesis through reducing PYCR1 expression. This provides a new perspective of NPC involving both miR-150-5p and PYCR1 for the treatment of NPC.

CBX3 Regulated By YBX1 Promotes Smoking-induced Pancreatic Cancer Progression via Inhibiting SMURF2 Expression

As a key reversible and heritable mechanism of transcriptional regulation, the epigenetic modification plays a crucial role in tumorigenesis. Of note, tobacco smoking induces epigenetic modifications to promote pancreatic cancer development. Chromobox protein homolog 3 (CBX3) acts as an epigenetic regulator, modulating gene expression of downstream targets via chromatin modifications. To date, the relationship between CBX3 and smoking in pancreatic cancer remains unknown. This study aimed to uncover the specific role and underlying mechanism of CBX3 in smoking-related pancreatic cancer. The bioinformatics analyses were conducted to identify CBX3 as a key player in tobacco-induced pancreatic cancer. The abnormal upregulation of CBX3 was associated with poor prognosis in pancreatic cancer patients. Moreover, cigarette smoke extract (CSE) exposure promoted the overexpression of Y-box-binding protein 1 (YBX1), which consequently led to upregulated CBX3 in pancreatic cancer cells. We also revealed that CBX3 enhanced pancreatic cancer progression, likely by inhibiting the expression of SMAD specific E3 ubiquitin protein ligase 2 (SMURF2) and promoting the activation of TGF-β signaling. In summary, the YBX1/CBX3/SMURF2 signaling axis may be a promising therapeutic target in patients with smoking-related pancreatic cancer.

lncRNA ELFN1-AS1 predicts poor prognosis and promotes tumor progression of non-small cell lung cancer by sponging miR-497

BACKGROUND: More novel biomarkers need to be discovered to improve the therapeutic efficiency of non-small cell lung cancer (NSCLC). lncRNA ELFN1-AS1 (ELFN1-AS1) was proved to play crucial roles in numerous diseases, its intention in NSCLC remains unclear. OBJECTIVE: This study aimed to investigate the function of ELFN1-AS1 and its potential mechanism in NSCLC development. METHODS: A total of 117 NSCLC patients were recruited and provided paired NSCLC tissues and normal tissues. The expression of ELFN1-AS1 was analyzed by PCR. The biological function of ELFN1-AS1 was estimated by CCK8 and Transwell assay. Additionally, the potential mechanism underlying the function of ELFN1-AS1 was explored by the dual-luciferase reporter assay and western blotting. RESULTS: The significant upregulation of ELFN1-AS1 was found in NSCLC tissues and cells, which was closely associated with the TNM stage, lymph node metastasis status, and overall survival of patients. The knockdown of ELFN1-AS1 was found to inhibit the cellular processes and EMT of NSCLC. Moreover, ELFN1-AS1 was found to serve as a sponge to binding with miR-497, and CCNE1 was demonstrated to be the downstream target of miR-497, which was speculated as the potential mechanism underlying the function of ELFN1-AS1. CONCLUSIONS: ELFN1-AS1 acts as an independent prognostic biomarker and tumor promoter of NSCLC by sponging miR-497/CCNE1 axis.

MicroRNA hsa-miR-657 promotes retinoblastoma malignancy by inhibiting peroxisome proliferator-activated receptor alpha expression

Retinoblastoma is a familial inherited embryonic neuroretinal malignancy with a low survival rate and poor prognosis. Our study aimed to evaluate the potential interaction between microRNA miR-657 and the peroxisome proliferator-activated receptor alpha (PPARA) in retinoblastoma. Expression of miR-657 and PPARA was analyzed in retinoblastoma tissues and cells using RT-qPCR. Cell proliferation, apoptosis, and migration were measured in retinoblastoma cell lines, and xenografting experiments were performed using nude mice. Our study showed that miR-657 expression was markedly increased, whereas that of PPARA was markedly decreased in retinoblastoma. Additionally, PPARA knockdown enhanced the development of retinoblastoma. miR-657 enhanced the retinoblastoma tumorigenesis by directly inhibiting PPARA expression, suggesting that PPARA targeting by miR-657 facilitates retinoblastoma development by enhancing cell growth. This study provides novel insights into the miR-657- and PPARA-mediated mechanisms underlying retinoblastoma progression and suggests that the interaction between miR-657 and PPARA may serve as an effective target for therapeutic intervention.

MiR-106b-5p regulates esophageal squamous cell carcinoma progression by binding to HPGD

BACKGROUND

Several studies have documented the key role of microRNAs (miRNAs) in esophageal squamous cell carcinoma (ESCC). Although the expression of the 15-hydroxyprostaglandin dehydrogenase (HPGD) gene and miR-106b-5p are reportedly linked to cancer progression, their underlying mechanisms in ESCC remain unclear.

METHODS

mRNA and miRNA expression in ESCC tissues and cells were analyzed using RT-qPCR. Luciferase and RNA pull-down assays were used to identify the interaction between miR-106b-5p and HPGD. Xenograft and pulmonary metastasis models were used to assess tumor growth and metastasis. CCK-8, BrdU, colony formation, adhesion, cell wound healing, Transwell, and caspase-3/7 activity assays, and flow cytometry and western blot analyses were used to examine the function of miR-106-5p and HPGD in ESCC cell lines.

RESULTS

The findings revealed that miR-106b-5p expression was upregulated in ESCC tissues and cell lines. miR-106b-5p augmented cellular proliferation, colony formation, adhesion, migration, invasion, and proportion of cells in the S-phase, but reduced apoptosis and the proportion of cells in G1-phase. Silencing of miR-106-5p inhibited tumor growth in vivo and pulmonary metastasis. Although HPGD overexpression suppressed proliferation, colony formation, adhesion, migration, and invasion of ESCC cells, it promoted apoptosis and caused cell cycle arrest of the ESCC cells. The results also indicated a direct interaction of HPGD with miR-106b-5p in ESCC cells. Furthermore, miR-106b-5p inhibited HPGD expression, thereby suppressing ESCC tumorigenesis.

CONCLUSION

Our data suggest that miR-106b-5p enhances proliferation, colony formation, adhesion, migration, and invasion, and induces the cycle progression, but represses apoptosis of ESCC cells by targeting HPGD. This suggests that the miR-106b-5p/HPGD axis may serve as a promising target for the diagnosis and treatment of ESCC.

miR-4324 inhibits ovarian cancer progression by targeting FEN1

Background

Ovarian cancer is one of the most lethal malignancies, with a 1.9% mortality rate worldwide. The dysregulation of the FEN1 gene and miR-4324 has been associated with cancer progression. However, the relationship between miR-4324 and-FEN1 requires further investigation.

Methods

miR-4324 and FEN1 expressions in ovarian cancer tissues and cell lines were measured via RT-qPCR. The interaction between miR-4324 and FEN1 was assessed using luciferase and RNA pull-down assays. The effects of miR-4324 and FEN1 on cell proliferation, adhesion and apoptosis were determined by CCK-8, BrdU, colony formation, cell adhesion, Caspase-3 and western blot assays in ovarian cancer cell lines CaOV3 and OVCAR3, respectively.

Results

The results showed that miR-4324 expression was significantly decreased and FEN1 expression was enhanced in ovarian cancer tissues and cell lines. miR-4324 inhibitor promoted cell proliferation, adhesion and migration, and prevented apoptosis. Furthermore, the downregulation of FEN1 inhibited ovarian cancer cell growth and increased apoptosis. miR-4324 inhibited FEN1 expression and repressed ovarian cancer progression.

Conclusion

Our study found that miR-4324 inhibited FEN1 expression, suppressed cell growth, and increased apoptosis in ovarian cancer cells. Therefore, we identified miR-4324 and FEN1 as potential therapeutic targets for ovarian cancer treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-022-00959-5.

Hsa_circ_0005230 is up-regulated and promotes gastric cancer cell invasion and migration via regulating the miR-1299/RHOT1 axis

Gastric cancer (GC) is one of the most common cancers in the world. Circular RNAs (circRNAs) are a class of non-coding RNAs that are widely expressed in eukaryotic cells. However, their role has been poorly understood in GC. This report aimed to explore the biological functions of hsa_circ_0005230 and its action mechanism in GC. This study validated that hsa_circ_0005230 was significantly up-regulated in 130 cases of GC tissues using qRT-PCR, and clinicopathological feature analysis revealed that its high expression was positively associated with histological grade, lymph node metastasis, TNM stages, and poor prognosis. In vitro, functional experiments showed that silencing hsa_circ_0005230 significantly decreased GC cell proliferation, invasion and migration capabilities. In addition, the major proteins of EMT (epithelial-mesenchymal transition) relevance have changed. In mechanism studies, bioinformatics analyses were used to predict the hsa_circ_0005230/miR-1299/RHOT1 axis and hsa_circ_0005230 may serve as a sponge for miR-1299 and indirectly regulate the expression of RHOT1. The regulated relationships between the molecules on the axis were verified using qRT-PCR and correlation analysis. Dual-luciferase reporter gene assay has been used to verify the binding site between miR-1299 and RHOT1. WB (Western blotting) and IHC (Immunohistochemical) were used to verify that RHOT1 may play the role of oncoprotein and affect the biological behavior of GC. Overall, hsa_circ_0005230 could enhance the EMT phenotype by promoting RHOT1 expression through sponging miR-1299, thus affecting the biological behavior of GC. Hsa_circ_0005230 can be easily identified as a potential diagnostic biomarker and assessment prognosis target for GC.

MicroRNA-195-3p promotes hepatic stellate cell activation and liver fibrosis by suppressing PTEN expression

Liver fibrosis is a reversible wound healing reaction characterized by abnormal accumulation of extracellular matrix (ECM) in response to liver injury. Recent studies have shown that it can be epigenetically regulated, especially by microRNAs (miRNAs). It has been acknowledged that activation of hepatic stellate cells (HSCs) is a pivotal step in the initiation and progression of liver fibrosis. Notably, our results showed that miR-195-3p was increased in HSCs isolated from CCl₄-treated mice and that the increase was more pronounced as the degree of liver fibrosis increased. Moreover, treatment of LX-2 cells, a human immortalized hepatic stellate cell line, with TGF-β1 resulted remarkable upregulation of miR-195-3p. Gain-of-function and loss-of-function experiments have suggested that the increased levels of miR-195-3p inhibit the expression of phosphatase and tension homolog deleted on chromosome 10 (PTEN), a negative regulator of the PI3K/Akt/mTOR signaling pathway in liver fibrosis, thereby contributing to HSC activation and proliferation and promoting the expression of profibrotic genes, such as α-SMA and collagen I, in LX-2 cells, which accelerates the accumulation of fibrous extracellular matrix deposition in the liver, while knockdown of miR-195-3p induced the opposite effect. Taken together, these results provide evidence for the harmful role of miR-195-3p in CCl₄-treated mouse liver fibrosis.

Downregulation of NEDD4L by EGFR signaling promotes the development of lung adenocarcinoma

Cumulative evidence indicates that the abnormal regulation of the NEDD4 family of E3-ubiquitin ligases participates in the tumorigenesis and development of cancer. However, their role in lung adenocarcinoma (LUAD) remains unclear. This study comprehensively analyzed the NEDD4 family in LUAD data sets from public databases and found only NEDD4L was associated with the overall survival of LUAD patients. Gene set enrichment analysis (GSEA) indicated that NEDD4L might be involved in the regulation of mTORC1 pathway. Both cytological and clinical assays showed that NEDD4L inhibited the activity of the mTOR signaling pathway. In vivo and in vitro experiments showed that NEDD4L could significantly inhibit the proliferation of LUAD cells. In addition, this study also found that the expression of NEDD4L was regulated by EGFR signaling. These findings firstly revealed that NEDD4L mediates an interplay between EGFR and mTOR pathways in LUAD, and suggest that NEDD4L held great potential as a novel biomarker and therapeutic target for LUAD.

MicroRNA MiR-130a-3p promotes gastric cancer by targeting Glucosaminyl N-acetyl transferase 4 (GCNT4) to regulate the TGF-β1/SMAD3 pathway

Gastric cancer is the third-leading cause of cancer-related deaths worldwide. Dysregulation of glucosaminyl (N-acetyl) transferase 4 (GCNT4) gene and miR-130a-3p gene has been reported in the development of gastric cancer. We elucidated the function of the miR-130a-3p-GCNT4 axis in gastric cancer. Reverse transcription quantitative polymerase-chain reaction measured miR-130a-3p and GCNT4 levels in gastric cancer tissues and cells. The interaction between miR-130a-3p and GCNT4 was assessed using luciferase and RNA pull-down assays. Biological roles of miR-130a-3p and GCNT4 were determined using cell proliferation, migration, and invasion assays in gastric cancer cells. In addition, the effect of miR-130a-3p on the tumor growth in vivo was investigated using tumor xenografts assay. Levels of total TGF-β1, phosphorylated SMAD3 (p-SMAD3), and SMAD3 were measured by using western blot. The results showed that miR-130a-3p levels were increased, while GCNT4 levels were reduced in gastric cancer tissues and cell lines. While miR-130a-3p mimics facilitated cellular proliferation, migration, and invasion in vitro, promoted tumor growth in vivo, and activated the TGF-β1/SMAD3 signaling pathway, overexpression of GCNT4 prevented the growth of gastric cancer cells and restrained the activation of the TGF-β1/SMAD3 pathway. Mechanistically, miR-130a-3p suppressed gastric cancer genesis by inhibiting GCNT4 expression and activating the TGF-β1/SMAD3 signaling pathway. Altogether, we proposed that targeting of GCNT4 and activation of the TGF-β1/SMAD3 signaling pathway by miR-130a-3p enhanced the growth of gastric cancer cells. This study provides important strategies for the selection of therapeutic targets for gastric cancer treatment involving miR-130a-3p/GCNT4/TGF-β1/SMAD3 axis.

MicroRNA hsa-miR-150-5p inhibits nasopharyngeal carcinogenesis by suppressing PYCR1 (pyrroline-5-carboxylate reductase 1)

Nasopharyngeal cancer is a rare cancer type, but with a low five-year survival rate. Dysregulation of pyrroline-5-carboxylate reductase 1 (PYCR1) and microRNA hsa-miR-150-5p is involved in the development of various cancers. However, the molecular mechanism of the hsa-miR-150-5p-PYCR1 axis in nasopharyngeal cancer remains unclear. To identify the mechanism of the hsa-miR-150-5p-PYCR1 axis, the expression of hsa-miR-150-5p and PYCR1 in nasopharyngeal cancer tissues and cells was first measured by reverse transcription quantitative polymerase chain reaction. The luciferase and RNA pull-down assays were used to confirm the interaction between hsa-miR-150-5p and PYCR1. The overexpression of hsa-miR-150-5p and PYCR1 was detected by cell viability, proliferation, western blotting, migration, and invasion in nasopharyngeal cancer cells. The expression levels of hsa-miR-150-5p was reduced in the nasopharyngeal cancer tissues and cells and were negatively correlated with the PYCR1 levels. The upregulation of hsa-miR-150-5p significantly repressed cell growth and promoted apoptosis. However, the upregulation of PYCR1 expression significantly promoted nasopharyngeal carcinogenesis, which could abolish the inhibitory effect of hsa-miR-150-5p. In conclusion, we clarified that hsa-miR-150-5p attenuated nasopharyngeal carcinogenesis by reducing the PYCR1 expression levels. This provides a new perspective of nasopharyngeal cancer involving both hsa-miR-150-5p and PYCR1 for the treatment of nasopharyngeal cancer.

miR-362-3p suppresses ovarian cancer by inhibiting LRP8

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MiR-362-3p inhibited cell viability and proliferation of ovarian cancer cells.

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MiR-362-3p inhibited cell migration and invasion of ovarian cancer cells.

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MiR-362-3p inhibited OV growth in vivo.

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LRP8 was a target of miR-362-3p.

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MiR-362-3p targeting LRP8 repressed cell viability and proliferation of ovarian cancer cells.

Background

Ovarian cancer is one of the most common female cancers, with a high incidence worldwide. Aberrant expression of low‐density lipoprotein (LDL) receptor‐related protein 8 (LRP8) and microRNA (miR)-362-3p is involved in the pathogenesis of different cancers.

Methods

We aimed to elucidate the underlying mechanism of the miR-362-3p-LRP8 axis in ovarian cancer. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to examine miR-362-3p and LRP8 expression in ovarian cancer tissues and cells. The luciferase assay was used to determine the relationship between miR-362-3p and LRP8. The function of overexpression of miR-362-3p and LRP8 was determined by assessing the cell viability using the cell counting kit 8 (CCK-8) assay, proliferation using 5′‑bromo-2′-deoxyuridine (BrdU) assay, migration using wound healing assay, invasion using transwell assay, and the protein expression levels of matrix metalloproteinase (MMP)-2, MMP9, and integrin α5 or β1 using western blotting assays in ovarian cancer cells.

Results

miR-362-3p expression levels were decreased in ovarian cancer tissues and cells and negatively correlated with LRP8 levels. Overexpression of miR-362-3p dramatically repressed cell growth. Furthermore, overexpression of LRP8 significantly facilitated the proliferation, migration, and invasion of ovarian cancer cells, which counteracted the inhibitory effect of miR-362-3p on ovarian cancer cell growth.

Conclusions

We reported that miR-362-3p hampered cell growth by repressing LRP8 expression in ovarian cancer cells. Our results provide new insights into ovarian cancer, involving both miR-362-3p and LRP8, which can be used as potential biomarkers for the treatment of ovarian cancer.

MicroRNA-411-3p inhibits bleomycin-induced skin fibrosis by regulating transforming growth factor-β/Smad ubiquitin regulatory factor-2 signalling

Skin fibrosis, which is characterized by fibroblast proliferation and increased extracellular matrix, has no effective treatment. An increasing number of studies have shown that microRNAs (miRNAs/miRs) participate in the mechanism of skin fibrosis, such as in limited cutaneous systemic sclerosis and pathological scarring. The objective of the present study was to determine the role of miR‐411‐3p in bleomycin (BLM)‐induced skin fibrosis and skin fibroblast transformation. Using Western blot analysis and real‐time quantitative polymerase chain reaction assess the expression levels of miR‐411‐3p, collagen (COLI) and transforming growth factor (TGF)‐β/Smad ubiquitin regulatory factor (Smurf)‐2/Smad signalling factors both in vitro and in vivo with or without BLM. To explore the regulatory relationship between miR‐411‐3p and Smurf2, we used the luciferase reporter assay. Furthermore, miR‐411‐3p overexpression was identified in vitro and in vivo via transfection with Lipofectamine 2000 reagent and injection. Finally, we tested the dermal layer of the skin using haematoxylin and eosin and Van Gieson's staining. We found that miR‐411‐3p expression was decreased in bleomycin (BLM)‐induced skin fibrosis and fibroblasts. However, BLM accelerated transforming growth factor (TGF)‐β signalling and collagen production. Overexpression of miR‐411‐3p inhibited the expression of collagen, F‐actin and the TGF‐β/Smad signalling pathway factors in BLM‐induced skin fibrosis and fibroblasts. In addition, miR‐411‐3p inhibited the target Smad ubiquitin regulatory factor (Smurf)‐2. Furthermore, Smurf2 was silenced, which attenuated the expression of collagen via suppression of the TGF‐β/Smad signalling pathway. We demonstrated that miR‐411‐3p exerts antifibrotic effects by inhibiting the TGF‐β/Smad signalling pathway via targeting of Smurf2 in skin fibrosis.

miR‑497/MIR497HG inhibits glioma cell proliferation by targeting CCNE1 and the miR‑588/TUSC1 axis

Emerging evidence has shown that microRNA (miR)-497 serves pivotal roles in tumorigenesis, cancer progression, metastasis and chemotherapy resistance in several types of cancer. In the present study, the expression and biological functions of miR-497 host gene (MIR497HG) were investigated in glioma tissue. The expression levels of miR-497 and MIR497HG were measured in glioma, adjacent non-cancerous and normal brain tissue and their association with the prognosis of patients with glioma were analyzed. The biological roles of miR-497 and MIR497HG were investigated in glioma cell lines. In addition, bioinformatics analysis, luciferase reporter assay and functional experiments were performed to identify and validate the downstream targets of miR-497 or MIR497HG. The expression levels of miR-497 and MIR497HG were downregulated in glioma tissue and cell lines compared with those in adjacent non-cancerous and normal brain tissue and normal human cortical neuron cell line. Patients with low miR-497 or MIR497HG expression levels exhibited a poor prognostic outcome. In addition, forced overexpression of miR-497 or MIR497HG significantly inhibited the proliferation and cell cycle progression of glioma cell lines. Furthermore, the results indicated that miR-497 and MIR497HG exerted their biological functions by direct targeting of cyclin E1 and miR-588/tumor suppressor candidate 1. In summary, the data indicated that miR-497 and MIR497HG served as tumor suppressors and may be used as potential therapeutic targets and prognostic biomarkers in glioma.

MiR-1207-5p targets PYCR1 to inhibit the progression of prostate cancer

Prostate cancer, the most common non-cutaneous male cancer, is a public health problem with a third prevalence worldwide. PYCR1 and miR-1207-5p dysregulations were found in cancer progression. Our study aims to reveal the biological role of miR-1207-5p-PYCR1 axis in prostate cancer progression. First, we investigated the expression of miR-1207-5p in prostate cancer tissues and cell lines by RT-qPCR. Next, we confirmed miR-1207-5p targeting PYCR1 by luciferase assay. CCK-8 assay, BrdU assay, flow cytometry, and tanswell assay were applied for examining cell proliferation, apoptosis, and invasion in prostate cancer cells, respectively. In the present study, decreased miR-1207-5p expression was obviously observed in prostate cancer tissues and cells. Upregulation of miR-1207-5p hampered cellular proliferation and invasion, while enhanced cellular apoptosis. In addition, upregulation of PYCR1 elevated cell proliferation and invasion, but repressed apoptosis of prostate cancer cells. Moreover, miR-1207-5p inhibited the expression of PYCR1 to repress prostate cancer tumorigenesis. MiR-1207-5p inhibited the expression of PYCR1 to repress the progression of prostate cancer by inhibiting cell growth and elevating cell apoptosis. Overall, our study clarifies the biological role of miR-1207-5p-PYCR1 axis in prostate cancer progression, which might be effective biomarkers for clinical treatment of prostate cancer.

miR-199a-3p plays an anti-tumorigenic role in lung adenocarcinoma by suppressing anterior gradient 2

Previous studies have explored the association between protein-coding genes and microRNAs (miRNAs) in lung adenocarcinoma (LUAD). However, the influence of the miR-199a-3p/anterior gradient 2 (AGR2) axis in LUAD has not yet been fully explored. Therefore, this study aimed to examine the underlying roles of AGR2 and miR-199a-3p in the development of LUAD. The expression levels of miR-199a-3p and AGR2 in LUAD tissues and cells were detected via quantitative reverse transcription-polymerase chain reaction (qRT-PCR). A luciferase assay was also performed to identify the interaction between AGR2 and miR-199a-3p. Moreover, the cell counting kit 8 (CCK-8), 5'-bromo-2'-deoxyuridine (BrdU), and adhesion assays were used along with flow cytometry to verify the malignancy of LUAD in vitro, while a xenograft tumor assay was performed to confirm the tumor growth in vitro. The findings showed a decrease in the expression of miR-199a-3p in LUAD. Additionally, miR-199a-3p overexpression inhibited the growth of LUAD cells in vitro and in vivo, while elevating the apoptosis rate of the cells. AGR2 knockdown had the same effect in the cells as that of miR-199a-3p overexpression. It was also found that miR-199a-3p directly targeted AGR2 in LUAD cells to suppress tumorigenesis. In conclusion, this study suggests that miR-199a-3p plays an anti-tumorigenic role in LUAD by targeting AGR2. Moreover, our study provides insights into the development of novel therapeutic targets for the treatment of LUAD.

MicroRNA-497 induced by Clonorchis sinensis enhances the TGF-β/Smad signaling pathway to promote hepatic fibrosis by targeting Smad7

Background

Various stimuli, including Clonorchis sinensis infection, can cause liver fibrosis. Liver fibrosis is characterized by the activation of hepatic stellate cells (HSCs) with massive production of extracellular matrix (ECM). Our previous study showed that the TGF-β₁-induced Smad signaling pathway played a critical role in the activation of HSCs during liver fibrosis induced by worm infection; however, the mechanisms that modulate the TGF-β/Smad signaling pathway are still poorly understood. Accumulating evidence demonstrates that miRNAs act as an important regulator of activation of HSCs during liver fibrosis.

Methods

The target of miR-497 was determined by bioinformatics analysis combined with a dual-luciferase activity assay. LX-2 cells were transfected with miR-497 inhibitor and then stimulated with TGF-β₁ or excretory/secretory products of C. sinensis (CsESPs), and activation of LX-2 was assessed using qPCR or western blot. In vivo, the mice treated with CCl₄ were intravenously injected with a single dose of adeno-associated virus serotype 8 (AAV8) that overexpressed anti-miR-497 sequences or their scramble control for 6 weeks. Liver fibrosis and damage were assessed by hematoxylin and eosin (H&E) staining, Masson staining, and qPCR; the activation of the TGF-β/Smad signaling pathway was detected by qPCR or western blot.

Results

In the present study, the expression of miR-497 was increased in HSCs activated by TGF-β₁ or ESPs of C. sinensis. We identified that Smad7 was the target of miR-497 using combined bioinformatics analysis with luciferase activity assays. Transfection of anti-miR-497 into HSCs upregulated the expression of Smad7, leading to a decrease in the level of p-Smad2/3 and subsequent suppression of the activation of HSCs induced by TGF-β₁ or CsESPs. Furthermore, miR-497 inhibitor delivered by highly-hepatotropic (rAAV8) inhibited TGF-β/smads signaling pathway by targeting at Smad7 to ameliorate CCL4-induced liver fibrosis.

Conclusions

The present study demonstrates that miR-497 promotes liver fibrogenesis by targeting Smad7 to promote TGF-β/Smad signaling pathway transduction both in vivo and in vitro, which provides a promising therapeutic strategy using anti-miR-497 against liver fibrosis.

Graphical Abstract

MicroRNA-532-5p upregulation protects neurological deficits after ischemic stroke through inhibition of BTB and CNC homology 1

OBJECTIVE

MicroRNA (miR)-532-5p has been reported to protect against ischemic stroke (IS), while the underlying mechanism of miR-532-5p targeting BTB and CNC homology 1 (BACH1) in IS remains unknown. Thus, we aim to detect the role of miR-532-5p in IS via targeting BACH1.

METHODS

Blood samples were collected from IS patients and healthy controls. Rat middle cerebral artery occlusion (MCAO) models were established and intracerebrally injected with altered miR-532-5p or BACH1 plasmid vectors to reveal their roles in neurological function, brain tissue pathology and inflammation in MCAO. Expression of miR-532-5p and BACH1 in patients' blood samples and rat brain tissues was assessed, and the targeting relationship between miR-532-5p and BACH1 was confirmed.

RESULTS

MiR-532-5p was downregulated and BACH1 was upregulated in IS. BACH1 was targeted by miR-532-5p. Restored miR-532-5p or inhibited BACH1 improved neurological function and inhibited inflammation and apoptosis in MCAO rats. On the contrary, miR-532-5p reduction or BACH1 overexpression had totally opposite effects on MCAO rats. The protective role of miR-532-5p for MCAO rats was reversed by upregulated BACH1.

CONCLUSION

MiR-532-5p upregulation protects against neurological deficits after IS through inhibition of BACH1.

MicroRNA miR-502-5p inhibits ovarian cancer genesis by downregulation of GINS complex subunit 2

Ovarian cancer (OC) is one of the most common malignancies with high incidence and mortality and the eighth most common cancer-associated mortality in women worldwide. Aberrant expression of the GINS complex subunit 2 (GINS2) gene and miR-502-5p has been associated with cancer progression. This study aims to investigate the specific molecular mechanism of the miR-502-5p-GINS2 axis in OC. GINS2 and miR-502-5p expression in OC tissues and cell lines was measured using RT-qPCR. Next, we investigated the interaction between miR-502-5p and GINS2 using a luciferase assay. The role of the miR-502-5p-GINS2 axis was detected by assessing cell proliferation, migration, and apoptosis levels, such as caspase-3 activity and caspase-3 protein expression, in the OC cell lines CaOV3 and SKOV3, respectively. MiR-502-5p expression was decreased, and GINS2 expression was dramatically elevated in OC tissues and cells. Upregulation of miR-502-5p expression repressed cellular proliferation and migration levels but increased the cellular apoptosis level. GINS2 overexpression enhanced the proliferation and migration levels but hampered OC cell apoptosis. Moreover, miR-502-5p inhibited GINS2 expression and suppressed OC tumorigenesis. miR-502-5p targeting GINS2 suppressed OC progression by inhibiting cell growth and promoting cell apoptosis. Hence, we provide a comprehensive understanding of OC involving both miR-502-5p and GINS2, which might be effective therapeutic targets for OC patients.

MiR-195 inhibits the ubiquitination and degradation of YY1 by Smurf2, and induces EMT and cell permeability of retinal pigment epithelial cells

The dysregulated microRNAs (miRNAs) are involved in diabetic retinopathy progression. Epithelial mesenchymal transition (EMT) and cell permeability are important events in diabetic retinopathy. However, the function and mechanism of miR-195 in EMT and cell permeability in diabetic retinopathy remain largely unclear. Diabetic retinopathy models were established using streptozotocin (STZ)-induced diabetic mice and high glucose (HG)-stimulated ARPE-19 cells. Retina injury was investigated by hematoxylin-eosin (HE) staining. EMT and cell permeability were analyzed by western blotting, immunofluorescence, wound healing, and FITC-dextran assays. MiR-195 expression was detected via qRT-PCR. YY1, VEGFA, Snail1, and Smurf2 levels were detected via western blotting. The interaction relationship was analyzed via ChIP, Co-IP, or dual-luciferase reporter assay. The retina injury, EMT, and cell permeability were induced in STZ-induced diabetic mice. HG induced EMT and cell permeability in ARPE-19 cells. MiR-195, YY1, VEGFA, and Snail1 levels were enhanced, but Smurf2 abundance was reduced in STZ-induced diabetic mice and HG-stimulated ARPE-19 cells. VEGFA knockdown decreased Snail1 expression and attenuated HG-induced EMT and cell permeability. YY1 silence reduced VEGFA and Snail1 expression, and mitigated HG-induced EMT and cell permeability. YY1 could bind with VEGFA and Snail1, and it was degraded via Smurf2-mediated ubiquitination. MiR-195 knockdown upregulated Smurf2 to decrease YY1 expression and inhibited HG-induced EMT and cell permeability. MiR-195 targeted Smurf2, increased expression of YY1, VEGFA, and Snail1, and promoted HG-induced EMT and cell permeability. MiR-195 promotes EMT and cell permeability of HG-stimulated ARPE-19 cells by increasing VEGFA/Snail1 via inhibiting the Smurf2-mediated ubiquitination of YY1.

MicroRNA-744-5p inhibits glioblastoma malignancy by suppressing replication factor C subunit 2

Glioblastoma (GBM) is the most common malignant primary brain tumor, accounting for ~57% of all gliomas and 48% of all malignant primary central nervous system tumors in the United States. Abnormal expression of the replication factor C subunit 2 (RFC2) gene and microRNA (miR)-744-5p is associated with tumorigenic characteristics, including cellular proliferation, migration and invasiveness. However, the mechanism underlying the interaction between miR-744-5p and RFC2 in GBM remains unknown. Reverse transcription-quantitative (RT-q) PCR analysis of RFC2 and miR-744-5p was performed using GBM tumor tissues and cells, and the association between miR-744-5p and RFC2 was determined by dual-luciferase reporter assay. Cell Counting Kit 8, 5-bromo-2-deoxyuridine (BrdU), wound-healing and cellular adhesion assays, as well as the detection of caspase-3 activity and western blotting were used to detect cellular proliferation, migration and adhesion, caspase-3 activity, and Bax and Bcl-2 protein expression, respectively, in GBM cells. The results of the present study demonstrated that RFC2 expression was increased in GBM tissues and cell lines. Overexpression of RFC2 promoted cellular proliferation, migration, adhesion and an increase in Bcl-2 protein levels, and suppressed cellular caspase-3 activity and Bax protein expression, while silencing RFC2 resulted in the opposite effect. The effects of miR-744-5p inhibition were similar to those of RFC2 overexpression. Moreover, miR-744-5p was found to target RFC2 in GBM cells, and inhibiting the expression of RFC2 suppressed GBM tumorigenesis. In conclusion, the present study demonstrated that miR-744-5p targets RFC2 and suppresses the progression of GBM by repressing cellular proliferation, migration and Bcl-2 protein expression, and effectively promoting caspase-3 activity and Bax protein expression. These findings suggest a new target for the clinical treatment and improved prognosis of patients with GBM in the future.

Expression and Diagnostic Value of miR-497 and miR-1246 in Hepatocellular Carcinoma

OBJECTIVE

Serum microRNAs (miRNAs) may serve as biomarkers in various cancers. Our study aims to explore the roles of miR-497 and miR-1246 in hepatocellular carcinoma (HCC).

METHODS

The expression levels of miR-497 and miR-1246 were measured by RT-PCR. A correlation analysis was conducted between the expression levels of miR-497 and miR-1246 and clinicopathological characteristics of patients. The receiver operating characteristic (ROC) curve was applied to evaluate the diagnostic efficacy in HCC. In addition, bioinformatics tools were also utilized to predict the potential targets of miR-497 and miR-1246.

RESULTS

The expression level of miR-497 in HCC was significantly down-regulated compared with the control group while the miR-1246 revealed a significantly higher expression level in HCC. There was a significant correlation demonstrated between the expression levels of miR-497 and miR-1246 in preoperative serum of HCC and the differentiation degree, Tumor Node Metastasis (TNM) classification, and metastasis. The expression levels of serum miR-497 and miR-1246 were significantly associated with the diagnosis, prognosis, and overall survival rate of patients with HCC. Moreover, the potential target genes of miR-497 in HCC include ARL2, UBE2Q1, PHF19, APLN, CHEK1, CASK, SUCO, CCNE1, and KIF23. The low expression of these nine genes is associated with a better prognosis of HCC patients. AUTS2 is a novel target gene of miR-1246, and its low expression is significantly related to the low overall survival rate of HCC patients.

CONCLUSIONS

miR-497 and miR-1246 are possibly involved in the progression of HCC by regulating target genes, respectively, and could serve as biomarkers in HCC.

Interplay between SOX9 transcription factor and microRNAs in cancer

SOX transcription factors are critical regulators of development, homeostasis and disease progression and their dysregulation is a common finding in various cancers. SOX9 belongs to SOXE family located on chromosome 17. MicroRNAs (miRNAs) possess the capacity of regulating different transcription factors in cancer cells by binding to 3'-UTR. Since miRNAs can affect differentiation, migration, proliferation and other physiological mechanisms, disturbances in their expression have been associated with cancer development. In this review, we evaluate the relationship between miRNAs and SOX9 in different cancers to reveal how this interaction can affect proliferation, metastasis and therapy response of cancer cells. The tumor-suppressor miRNAs can decrease the expression of SOX9 by binding to the 3'-UTR of mRNAs. Furthermore, the expression of downstream targets of SOX9, such as c-Myc, Wnt, PI3K/Akt can be affected by miRNAs. It is noteworthy that other non-coding RNAs including lncRNAs and circRNAs regulate miRNA/SOX9 expression to promote/inhibit cancer progression and malignancy. The pre-clinical findings can be applied as biomarkers for diagnosis and prognosis of cancer patients.

MiR-328-3p inhibits lung adenocarcinoma-genesis by downregulation PYCR1

BACKGROUND

A vast majority of patients with NSCLC (non-small cell lung cancer) have lung adenocarcinoma (LA), and the survival rate of LA varies from 5% to 75% depending on the severity of this adenocarcinoma. PYCR1 (abnormal pyrroline-5-carboxylate reductase 1) gene and miR-328-3p have been found to be associated with cancer development. However, the underlying mechanism of interaction between miR-328-3p and PYCR1 in LA needs further investigation.

METHODS

The expressions of miR-328-3p and PYCR1 in samples with LA were identified by RT-qPCR. Next, we investigated the targeting relationship between these two biological factors using luciferase assay. CCK-8, BrdU, transwell-migration, and flow cytometry assays were performed to detect cell viability, cell proliferation, cell migration and cell apoptosis in LA cells.

RESULTS

We noticed that miR-328-3p expression was downregulated in LA samples. MiR-328-3p mimic restricted cell proliferation and cell migration, while it enhanced cell apoptosis. Furthermore, the overexpression of PYCR1 promoted the proliferation and migration of LA cells, but it repressed cell apoptosis. Moreover, PYCR1 directly interacted with miR-328-3p in the LA cells, and miR-328-3p restrained the expression of PYCR1, thus suppressing LA tumorigenesis.

CONCLUSION

In summary, our study revealed that miR-328-3p targeting to PYCR1 suppressed the malignancy of LA cells by impeding cell proliferation and migration, while effectively promoting cell apoptosis.

TMAO Aggregates Neurological Damage Following Ischemic Stroke by Promoting Reactive Astrocytosis and Glial Scar Formation via the Smurf2/ALK5 Axis

Ischemic stroke has been reported to cause significant changes to memory, thinking, and behavior. Intriguingly, recently reported studies have indicated the association of Trimethylamine N-oxide (TMAO) with the acute phase of ischemic stroke. However, the comprehensive underlying mechanism remained unknown. The objective of the present study was to investigate the association between TMAO and recovery of neurological function after ischemic stroke. For this purpose, a middle cerebral artery occlusion/reperfusion (MCAO/R) rat model was established and treated with TMAO or/and sh-ALK5, followed by the neurological function evaluation. Behaviors of rats were observed through staircase and cylinder tests. Moreover, the expression of Smurf2 and ALK5 was detected by immunohistochemistry while expression of GFAP, Neurocan, and Phosphacan in brain tissues was determined by immunofluorescence. Thereafter, gain- and loss-of-function assays in astrocytes, the proliferation, viability, and migration were evaluated by the EdU, CCK-8, and Transwell assays. Besides, Smurf2 mRNA expression was determined by the RT-qPCR, whereas, Smurf2, ALK5, GFAP, Neurocan, and Phosphacan expression was evaluated by the Western blotting. Finally, the interaction of Smurf2 with ALK5 and ALK5 ubiquitination was assessed by the co-immunoprecipitation. Notably, our results showed that TMAO promoted the proliferation of reactive astrocyte and formation of glial scar in MCAO/R rats. However, this effect was abolished by the Smurf2 overexpression or ALK5 silencing. We further found that TMAO upregulated the ALK5 expression by inhibiting the ubiquitination role of Smurf2. Overexpression of ALK5 reversed the inhibitory effect of Smurf2 on astrocyte proliferation, migration, and viability. Collectively, our work identifies the evolutionarily TMAO/Smurf2/ALK5 signaling as a major genetic factor in the control of reactive astrocyte proliferation and glial scar formation in ischemic stroke, thus laying a theoretical foundation for the identification of ischemic stroke.

Smurf2 exerts neuroprotective effects on cerebral ischemic injury

The present study aimed to explore specific mechanisms involved in mediating the neuroprotective effects of Smad ubiquitination regulatory factor 2 (Smurf2) in cerebral ischemic injury. A middle cerebral artery occlusion (MCAO) mouse model and an oxygen–glucose deprivation (OGD)–treated neuron model were developed. The expression of Smurf2, Yin Yang 1 (YY1), hypoxia-inducible factor-1 alpha (HIF1α), and DNA damage–inducible transcript 4 gene (DDIT4) was analyzed. Thereafter, the expression of Smurf2, YY1, HIF1α, and DDIT4 was altered in the MCAO mice and OGD-treated neurons. Apoptosis in tissues and cerebral infarction were assessed. In neurons, the expression of apoptosis-related proteins, viability, and apoptosis were assessed, followed by evaluation of lactate dehydrogenase leakage rate. The interaction between Smurf2 and YY1 was analyzed by coimmunoprecipitation assay and that between YY1 ubiquitination by in vivo ubiquitination experiment. The results showed downregulation of Smurf2 and upregulation of YY1, HIF1α, and DDIT4 in both MCAO mice and OGD-treated neurons. Smurf2 elevated YY1 ubiquitination and degradation, and YY1 increased HIF1α expression to promote DDIT4 in neurons. Overexpressed Smurf2 or downregulated YY1, HIF1α, or DDIT4 reduced the volume of cerebral infarction and apoptosis in MCAO mice, while enhancing cell viability and reducing apoptosis and lactate dehydrogenase leakage in OGD-treated neurons. In summary, our findings elucidated a neuroprotective role of Smurf2 in cerebral ischemic injury via inactivation of the YY1/HIF1α/DDIT4 axis.

Differential roles of miR-15a/16-1 and miR-497/195 clusters in immune cell development and homeostasis

MicroRNAs (miRNAs) post-transcriptionally repress almost all genes in mammals and thereby form an additional layer of gene regulation. As such, miRNAs impact on nearly every physiological process and have also been associated with cancer. Prominent examples of such miRNAs can be found in the miR-15 family, composed of the bicistronic clusters miR-15a/16-1, miR-15b/16-2, and miR-497/195. In particular, the miR-15a/16-1 cluster is deleted in almost two thirds of all chronic B lymphocytic leukemia (CLL) cases, a phenotype that is also recapitulated by miR-15a/16-1-deficient as well as miR-15b/16-2-deficient mice. Under physiological conditions, those two clusters have been implicated in T-cell function, and B-cell and natural killer (NK) cell development; however, it is unclear whether miR-497 and miR-195 confer similar roles in health and disease. Here, we have generated a conditional mouse model for tissue-specific deletion of miR-497 and miR-195. While mice lacking miR-15a/16-1 in the hematopoietic compartment developed clear signs of CLL over time, aging mice deficient for miR-497/195 did not show such a phenotype. Likewise, loss of miR-15a/16-1 impaired NK and early B-cell development, whereas miR-497/195 was dispensable for these processes. In fact, a detailed analysis of miR-497/195-deficient mice did not reveal any effect on steady-state hematopoiesis or immune cell function. Unexpectedly, even whole-body deletion of the cluster was well-tolerated and had no obvious impact on embryonic development or healthy life span. Therefore, we postulate that the miR-497/195 cluster is redundant to its paralog clusters or that its functional relevance is restricted to certain physiological and pathological conditions.

Role and clinical significance of TGF‑β1 and TGF‑βR1 in malignant tumors (Review)

The appearance and growth of malignant tumors is a complicated process that is regulated by a number of genes. In recent years, studies have revealed that the transforming growth factor-β (TGF-β) signaling pathway serves an important role in cell cycle regulation, growth and development, differentiation, extracellular matrix synthesis and immune response. Notably, two members of the TGF-β signaling pathway, TGF-β1 and TGF-β receptor 1 (TGF-βR1), are highly expressed in a variety of tumors, such as breast cancer, colon cancer, gastric cancer and hepatocellular carcinoma. Moreover, an increasing number of studies have demonstrated that TGF-β1 and TGF-βR1 promote proliferation, migration and epithelial-mesenchymal transition of tumor cells by activating other signaling pathways, signaling molecules or microRNAs (miRs), such as the NF-κB signaling pathway and miR-133b. In addition, some inhibitors targeting TGF-β1 and TGF-βR1 have exhibited positive effects in in vitro experiments. The present review discusses the association between TGF-β1 or TGF-βR1 and tumors, and the development of some inhibitors, hoping to provide more approaches to help identify novel tumor markers to restrain and cure tumors.

Small in Size, but Large in Action: microRNAs as Potential Modulators of PTEN in Breast and Lung Cancers

MicroRNAs (miRNAs) are well-known regulators of biological mechanisms with a small size of 19–24 nucleotides and a single-stranded structure. miRNA dysregulation occurs in cancer progression. miRNAs can function as tumor-suppressing or tumor-promoting factors in cancer via regulating molecular pathways. Breast and lung cancers are two malignant thoracic tumors in which the abnormal expression of miRNAs plays a significant role in their development. Phosphatase and tensin homolog (PTEN) is a tumor-suppressor factor that is capable of suppressing the growth, viability, and metastasis of cancer cells via downregulating phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling. PTEN downregulation occurs in lung and breast cancers to promote PI3K/Akt expression, leading to uncontrolled proliferation, metastasis, and their resistance to chemotherapy and radiotherapy. miRNAs as upstream mediators of PTEN can dually induce/inhibit PTEN signaling in affecting the malignant behavior of lung and breast cancer cells. Furthermore, long non-coding RNAs and circular RNAs can regulate the miRNA/PTEN axis in lung and breast cancer cells. It seems that anti-tumor compounds such as baicalein, propofol, and curcumin can induce PTEN upregulation by affecting miRNAs in suppressing breast and lung cancer progression. These topics are discussed in the current review with a focus on molecular pathways.

E3 Ubiquitin Ligases: Key Regulators of TGFβ Signaling in Cancer Progression

Transforming growth factor β (TGFβ) is a secreted growth and differentiation factor that influences vital cellular processes like proliferation, adhesion, motility, and apoptosis. Regulation of the TGFβ signaling pathway is of key importance to maintain tissue homeostasis. Perturbation of this signaling pathway has been implicated in a plethora of diseases, including cancer. The effect of TGFβ is dependent on cellular context, and TGFβ can perform both anti- and pro-oncogenic roles. TGFβ acts by binding to specific cell surface TGFβ type I and type II transmembrane receptors that are endowed with serine/threonine kinase activity. Upon ligand-induced receptor phosphorylation, SMAD proteins and other intracellular effectors become activated and mediate biological responses. The levels, localization, and function of TGFβ signaling mediators, regulators, and effectors are highly dynamic and regulated by a myriad of post-translational modifications. One such crucial modification is ubiquitination. The ubiquitin modification is also a mechanism by which crosstalk with other signaling pathways is achieved. Crucial effector components of the ubiquitination cascade include the very diverse family of E3 ubiquitin ligases. This review summarizes the diverse roles of E3 ligases that act on TGFβ receptor and intracellular signaling components. E3 ligases regulate TGFβ signaling both positively and negatively by regulating degradation of receptors and various signaling intermediates. We also highlight the function of E3 ligases in connection with TGFβ's dual role during tumorigenesis. We conclude with a perspective on the emerging possibility of defining E3 ligases as drug targets and how they may be used to selectively target TGFβ-induced pro-oncogenic responses.

Silencing of lncRNA MIR497HG via CRISPR/Cas13d Induces Bladder Cancer Progression Through Promoting the Crosstalk Between Hippo/Yap and TGF-β/Smad Signaling

A subset of long non-coding RNAs (lncRNAs), categorized as miRNA-host gene lncRNAs (lnc-miRHGs), is processed to produce miRNAs and involved in cancer progression. This work aimed to investigate the influences and the molecular mechanisms of lnc-miRHGs MIR497HG in bladder cancer (BCa). The miR-497 and miR-195 were derived from MIR497HG. We identified that lnc-miRHG MIR497HG and two harbored miRNAs, miR-497 and miR-195, were downregulated in BCa by analyzing The Cancer Genome Atlas and our dataset. Silencing of MIR497HG by CRISPR/Cas13d in BCa cell line 5637 promoted cell growth, migration, and invasion in vitro. Conversely, overexpression of MIR497HG suppressed cell progression in BCa cell line T24. MiR-497/miR-195 mimics rescued significantly the oncogenic roles of knockdown of MIR497HG by CRISPR/Cas13d in BCa. Mechanistically, miR-497 and miR-195 co-ordinately suppressed multiple key components in Hippo/Yap and transforming growth factor β signaling and particularly attenuated the interaction between Yap and Smad3. In addition, E2F4 was proven to be critical for silencing MIR497HG transcription in BCa cells. In short, we propose for the first time to reveal the function and mechanisms of MIR497HG in BCa. Blocking the pathological process may be a potential strategy for the treatment of BCa.

lncRNA SNHG1 Promotes Progression of Cervical Cancer Through miR-195/NEK2 Axis

Objective

Cervical cancer is a common gynecologic cancer, and no study has been reported on the way through which lncRNA SNHG1, miR-195 and NEK2 jointly affect cervical cancer cells (CCCs), so this paper will explore a new approach to the development of cervical cancer in this respect.

Methods

Altogether 72 cervical cancer tissues and 54 adjacent tissues were collected. qPCR was performed to quantify lncRNA SNHG1 and miR-195, whose expression vectors were constructed and then transfected into CCCs, so as to observe their effects on the cells. Western blotting (WB) was carried out to detect protein levels. MTT assay was conducted to detect cell activity. Flow cytometry was performed to detect cell apoptosis. Transwell was carried out to detect cell invasion and migration.

Results

The expression of lncRNA SNHG1 up-regulated while that of miR-195 down-regulated in CCCs. lncRNA SNHG1 regulated NEK2 through its targeted binding to miR-195. The down-regulation of lncRNA SNHG1 or the up-regulation of miR-195 led to the decrease of NEK2 and the reduction of cells’ activity, migration and invasion, also resulting in the increase of cell apoptosis. Rescue experiments showed that the down-regulation of miR-195 could offset the cell changes caused by lncRNA SNHG1.

Conclusion

lncRNA SNHG1 promotes the progression of cervical cancer through the miR-195/NEK2 axis, so lncRNA SNHG1, miR-195 and NEK2 may have potential values for diagnosing and treating cervical cancer.

MiR-497-5p Regulates Osteo/Odontogenic Differentiation of Stem Cells From Apical Papilla via the Smad Signaling Pathway by Targeting Smurf2

Osteo/odontogenic differentiation is a key process of human stem cells from apical papilla (SCAP) in tooth root development. Emerging evidence indicates microRNAs (miRNAs) play diverse roles in osteogenesis. However, their functions in osteo/odontogenic differentiation of SCAP require further elucidation. To investigate the role of miRNA in SCAP osteo/odontogenic differentiation and underlying mechanisms, miRNA microarray analysis was performed to screen differentially expressed miRNAs between control and osteo/odontogenic-induced group. Quantitative real-time PCR (qRT-PCR) and western blot were used to detected osteo/odontogenic differentiation-related markers and possible signaling pathway SCAP-associated genes. Alizarin Red Staining (ARS) were applied to evaluated osteogenic capacity. The results showed that miR-497-5p increased during SCAP osteo/odontogenic differentiation. Overexpression of miR-497-5p enhanced the osteo/odontogenic differentiation of SCAP, whereas downregulation of miR-497-5p elicited the opposite effect, thus suggesting that miR-497-5p is a positive regulator of the osteo/odontogenic differentiation of SCAP. Bioinformatic analysis and dual luciferase reporter assay identified that SMAD specific E3 ubiquitin protein ligase 2 (Smurf2) is a direct target of miR-497-5p. Further study demonstrated that Smurf2 negatively regulates SCAP osteo/odontogenic differentiation, and silencing Smurf2 could block the inhibitory effect of the miR-497-5p inhibitor. Meanwhile, pathway detection manifested that miR-497-5p promotes osteo/odontogenic differentiation via Smad signaling pathway. Collectively, our findings demostrate that miR-497-5p promotes osteo/odontogenic differentiation of SCAP via Smad signaling pathway by targeting Smurf2.