MiR-337-3p suppresses the proliferation and metastasis of clear cell renal cell carcinoma cells via modulating Capn4

FOXCUT regulates the malignant phenotype of triple-negative breast Cancer via the miR-337-3p/ANP32E Axis

BACKGROUND

The lack of specific molecular targets and the rapid spread lead to a worse prognosis of triple-negative breast cancer (TNBC). Therefore, identifying new therapeutic and prognostic biomarkers helps to develop effective treatment strategies for TNBC.

METHODS

Through preliminary bioinformatics analysis, FOXCUT was found to be significantly overexpressed in breast cancer, especially in TNBC. Tissue samples were collected from 15 TNBC patients, and qRT-PCR was employed to validate the expression of FOXCUT in both TNBC patient tissues and TNBC cell lines. We also carried out the GSEA analysis and KEGG enrichment analysis of FOXCUT. Additionally, the effects of FOXCUT knockdown on TNBC cell malignant behaviors, and aerobic glycolysis were assessed by methods including CCK-8, Transwell, western blot, and Seahorse XF 96 analyses. Moreover, utilizing databases predicting interactions between ceRNAs, corresponding lncRNA-miRNA binding relationships, and miRNA-mRNA interactions were predicted. These predictions were subsequently validated through RNA immunoprecipitation and dual-luciferase reporter assays.

RESULTS

FOXCUT exhibited high expression in both TNBC tissues and cell lines, fostering cell malignant behaviors and glycolysis. FOXCUT was found to sponge miR-337-3p, while miR-337-3p negatively regulated the expression of ANP32E. Consequently, FOXCUT ultimately facilitated the malignant phenotype of TNBC by upregulating ANP32E expression.

CONCLUSION

This study elucidated the role of FOXCUT in elevating aerobic glycolysis levels in TNBC and driving malignant cancer cell development via the miR-337-3p/ANP32E regulatory axis.

Circular RNA as a Biomarker for Diagnosis, Prognosis and Therapeutic Target in Acute and Chronic Lymphoid Leukemia

Circular RNAs (circRNAs) are single-stranded RNAs that have received much attention in recent years. CircRNAs lack a 5' head and a 3' poly-A tail. The structure of this type of RNAs make them resistant to digestion by exonucleases. CircRNAs are expressed in different cells and have various functions. The function of circRNAs is done by sponging miRNAs, changing gene expression, and protein production. The expression of circRNAs changes in different types of cancers, which causes changes in cell growth, proliferation, differentiation, and apoptosis. Changes in the expression of circRNAs can cause the invasion and progression of tumors. Studies have shown that changes in the expression of circRNAs can be seen in acute lymphoid leukemia (ALL) and chronic lymphoid leukemia (CLL). The conducted studies aim to identify circRNAs whose expression has changed in these leukemias and their more precise function so that these circRNAs can be identified as biomarkers, prediction of patient prognosis, and treatment targets for ALL and CLL patients. In this study, we review the studies conducted on the role and function of circRNAs in ALL and CLL patients. The results of the studies show that there is a possibility of using circRNAs as biomarkers in the identification and treatment of patients in the future.

A review on expression and regulatory mechanisms of miR-337-3p in cancer

A group of diseases generally referred to as cancer represents a serious threat to people's health all over the world and has a significant negative influence on every aspect of the lives of patients. The development of cancer is influenced by several environmental, genetic, and epigenetic factors. MicroRNAs (miRNAs), a class of non-coding RNAs, can alter the expression of genes involved in cell proliferation, migration, metastasis, and apoptosis, lead to the pathogenesis of cancer. Additionally, several effectors modify miRNAs directly, including methylation, circular RNAs, and long non-coding RNAs (lncRNAs). In this review, we have explained the role of mir-337-3p in the pathways related to the pathogenesis of different cancers. Studying the functional role of miR-337-3p is necessary for detecting novel molecules as tumor markers and discovering novel targets for cancer treatment.

Changes in the small noncoding RNA transcriptome in osteosarcoma cells

BACKGROUND

Osteosarcoma has the highest incidence among bone malignant tumors and mainly occurs in adolescents and the elderly, but the pathological mechanism is still unclear, which makes early diagnosis and treatment very difficult. Bone marrow mesenchymal stem cells (BMSCs) are considered to be one of the sources of osteosarcoma cells. Therefore, a full understanding of the gene expression differences between BMSCs and osteosarcoma cells is very important to explore the pathogenesis of osteosarcoma and facilitate the early diagnosis and treatment of osteosarcoma. Small noncoding RNAs (sncRNAs) are a class of RNAs that do not encode proteins but directly play biological functions at the RNA level. SncRNAs mainly include Piwi-interacting RNAs (piRNAs), small nucleolar RNAs (snoRNAs), small nuclear RNAs (snRNAs), repeat RNAs and microRNAs (miRNAs).

METHODS

In this study, we compared the expression of sncRNAs in BMSCs and osteosarcoma cells by high-throughput sequencing and qPCR and looked for differentially expressed sncRNAs. CCK-8, clone formation and transwell assay were used to detect the effect of sncRNA in MG63 cells.

RESULTS

We found that 66 piRNAs were significantly upregulated and 70 piRNAs were significantly downregulated in MG63 cells. As for snoRNAs, 71 snoRNAs were significantly upregulated and 117 snoRNAs were significantly downregulated in MG63 cells. As for snRNAs, 35 snRNAs were significantly upregulated and 17 snRNAs were significantly downregulated in MG63 cells. As for repeat RNAs, 6 repeat RNAs were significantly upregulated and 7 repeat RNAs were significantly downregulated in MG63 cells. As for miRNAs, 326 miRNAs were significantly upregulated and 281 miRNAs were significantly downregulated in MG63 cells. Overexpression of piRNA DQ596225, snoRNA ENST00000364830.2, snRNA ENST00000410533.1 and miRNA hsa-miR-369-5p inhibited the proliferation and migration of MG63 cells.

CONCLUSIONS

Our results provide a theoretical basis for the pathogenesis, early diagnosis and treatment of osteosarcoma.

Calpain as a therapeutic target in cancer

INTRODUCTION

Calpain-1 and calpain-2 are prototypical classical isoforms of the calpain family of calcium-activated cysteine proteases. Their substrate proteins participate in a wide range of cellular processes, including transcription, survival, proliferation, apoptosis, migration, and invasion. Dysregulated calpain activity has been implicated in tumorigenesis, suggesting that calpains may be promising therapeutic targets.

AREAS COVERED

This review covers clinical and basic research studies implicating calpain-1 and calpain-2 expression and activity in tumorigenesis and metastasis. We highlight isoform specific functions and provide an overview of substrates and cancer-related signalling pathways affected by calpain-mediated proteolytic cleavage. We also discuss efforts to develop clinically relevant calpain specific inhibitors and spotlight the challenges facing inhibitor development.

EXPERT OPINION

Rationale for targeting calpain-1 and calpain-2 in cancer is supported by pre-clinical and clinical studies demonstrating that calpain inhibition has the potential to attenuate carcinogenesis and block metastasis of aggressive tumors. The wide range of substrates and cleavage products, paired with inconsistencies in model systems, underscores the need for more complete understanding of physiological substrates and how calpain cleavage alters their function in cellular processes. The development of isoform specific calpain inhibitors remains an important goal with therapeutic potential in cancer and other diseases.

MicroRNA-337-3p impedes breast cancer progression by targeting cyclin-dependent kinase 1

MicroRNAs (miRNAs/miRs) function as key regulators in breast cancer (BC). The present study aimed to verify the function and molecular regulation of miR-337-3p in BC cells. Bioinformatics analysis was performed to screen key genes and miRNAs associated with BC. Reverse transcription-quantitative PCR and western blot analyses were performed to detect RNA and protein expression levels. Cell Counting Kit-8, BrdU and cell adhesion assays, and flow cytometric analysis were performed to assess the biological behaviors of BC cells. The dual-luciferase reporter, RNA pull-down assays, and Pearson's correlation analysis were performed to determine the association between miRNAs and mRNAs. Bioinformatics analysis revealed that miR-337-3p and cyclin-dependent kinase 1 (CDK1) acted as key regulators in BC. In addition, miR-337-3p was expressed at low levels in BC cells and tissues, which suppressed BC progression. CDK1 expression was upregulated in BC cells and tissues, which was associated with increased cell proliferation and adhesion, as well as decreased apoptosis in BC. Notably, miR-337-3p targeted CDK1 to inhibit BC cell progression. Taken together, the results of the present study suggest that miR-337-3p plays a tumor-suppressive role in BC by targeting CDK1.

Quaking I-5 protein inhibits invasion and migration of kidney renal clear cell carcinoma via inhibiting epithelial-mesenchymal transition suppression through the regulation of microRNA 200c

Background

It has been demonstrated that quaking I-5 protein (QKI-5) plays crucial roles in the metastasis of various kinds of cancers. However, the function and mechanism of QKI-5 in kidney renal clear cell carcinoma (KIRC) metastasis remains unclear. Therefore, this study aimed to explore the mechanism of QKI-5 in the metastasis of KIRC.

Methods

The expression of QKI-5 was detected using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot in KIRC tissues and different cell lines. Immunohistochemical staining was used to detect the quantity of QKI-5 in primary and metastases of KIRC. Cell migration and invasion were measured using wound healing and transwell assays respectively. The quantity of epithelial mesenchymal transition marker proteins was detected using western blot and immunofluorescence staining. The interaction of QKI-5 via microRNA 200c (miR-200c) was confirmed using dual luciferase reporter assay.

Results

Although QKI-5 was significantly more likely to be downregulated in KIRC tissues than that in normal Kidney tissues, it was dramatically elevated in metastatic KIRC tumors. Upregulation of QKI-5 promoted cell migration and invasion and elevated the expression of epithelial-mesenchymal transition (EMT) marker proteins, including vimentin, snail and slug, while it was downregulated for E-cadherin. Furthermore, a dual luciferase reporter assay demonstrated that QKI-5 was a direct target of miR-200c, and that miR-200c could reverse the effect of QKI-5 on cell migration, invasion, and expression of EMT marker proteins.

Conclusions

Our results revealed that downregulation of QKI-5 by miR-200c attenuated KIRC migration and invasion via the EMT process, indicating that QKI-5 may be a potential therapeutic target and a key indicator of KIRC progression.

MiR-337-3p suppresses migration and invasion of breast cancer cells by downregulating ESRP1

Breast cancer (BC) is a common malignant tumor in women, and a considerable number of studies show that aberrant expression of miRNA is correlated with BC development. By analyzing TCGA-BRCA database through bioinformatics method, this study disclosed that miR-337-3p was significantly low in BC tissue and might be a cancer inhibitor in BC. To explore the effect and potential mechanism of miR-337-3p in BC, qRT-PCR was used in this study to indicate that the expression of miR-337-3p was downregulated in BC cells. Then, the effects of miR-337-3p on BC cells were detected by western blot, Cell Counting Kit-8 (CCK-8), wound healing and Transwell assays. After upregulating miR-337-3p expression, the cell viability, migration, invasion and epithelial-mesenchymal transition (EMT) of BC cells were markedly inhibited while cell apoptosis remarkably increased. Besides, it was predicted and identified by bioinformatics analysis and dual-luciferase assay that ESRP1 was a target gene of miR-337-3p. Finally, the progression and EMT of BC cells were promoted after upregulating ESRP1 expression level. However, upregulating miR-337-3p as well as ESRP1 reduced the promotion on the malignant phenotype of BC cells. This result revealed that miR-337-3p could inhibit ESRP1 expression to perform its biological functions. In conclusion, it was illustrated in this study that miR-337-3p is a tumor-inhibitor of BC and plays its regulatory role via its downstream gene ESRP1.

Analysis of miRNA expression profile in lung tissues of an intermittent hypoxia rat model

We screened key miRNAs in an intermittent hypoxia rat model and explored the biological roles of downstream target genes and related regulatory pathways. We analyzed the expression profile of miRNAs in the lung tissues of rats in the 5 % (IH1), 7.5 % (IH2), 10 % (IH3), 12.5 % (IH4) oxygen concentration and negative control (NC) groups and identified common miRNAs. Multiple differentially expressed miRNAs were detected, and intersection of their expression profiles yielded 10 common miRNAs with 929 target genes mainly distributed in the nucleus. Molecular functions pertained mainly to the activation of transcription factors, while biological processes focused on cell interaction and signal transduction. Among signaling pathways, the top 5 included the LKB1 signaling, nectin adhesion, and S1P pathways. 8 of 10 common miRNAs had excellent diagnostic value for detecting intermittent hypoxia. The miRNAs binds to the target gene might play a key role in the pathophysiological process of OSA through the LKB1/AMPK and S1P/Akt/eNOS signaling pathways.

MiR-337-3p lowers serum LDL-C level through targeting PCSK9 in hyperlipidemic mice

BACKGROUND

Reducing serum low-density lipoprotein cholesterol (LDL-C) in hyperlipemia is recognized as an effective strategy to minimize the risk of atherosclerotic cardiovascular disease (ASCVD). MiR-337-3p has already been discovered to play regulatory roles in tumor proliferation and metastasis, adipocyte browning and ischemic brain injury, etc. However, the association between miR-337-3p and LDL-C is unknown.

METHODS

Gene Expression Omnibus (GEO) dataset and two hyperlipidemic murine models were used to analyze the potential relationship between miR-337-3p and LDL-C. AAV-mediated liver-directed miRNA overexpression in high fat diet (HFD)-fed mouse model was used to examine the effect of miR-337-3p on LDL-C and WB/RT-PCR/ELISA/luciferase assays were used to investigate the underlying mechanism.

RESULTS

The expressions of miR-337-3p were obviously lower in multiple hyperlipidemic mouse models and had a negative correlation with serum LDL-C levels. After confirming the effect of miR-337-3p on the improvement of serum LDL-C in vivo, we discovered PCSK9 might be a possible target of miR-337-3p, which was further proved by in vitro experiments. MiR-337-3p could directly interact with both the PCSK9 3'UTR and promoter to inhibit PCSK9 translation and transcription. Furthermore, the result from DiI-LDL uptake assay under the knockdown of PCSK9 demonstrated that miR-337-3p promoting the absorption of LDL-C in HepG2 cells was dependent on PCSK9, and the result from LDLR-/- mouse model indicated that miR-337-3p regulating LDL-C was dependent on PCSK9/LDLR pathway.

CONCLUSION

We discovered a new function of miR-337-3p in regulating PCSK9 expression and LDL-C absorption, suggesting miR-337-3p might be a new therapeutic target for the development of antihyperlipidemic drug.

Aberrant microRNA expression in B lymphocytes from patients with primary warm autoimmune haemolytic anaemia

OBJECTIVE

To screen and analyze the micro-Ribonucleic Acid (miRNA) expression profile in B lymphocytes from patients with autoimmune haemolytic anaemia (AIHA) using high-throughput sequencing.

METHODS

Twelve patients with warm autoimmune haemolytic anaemia (wAIHA) and twelve healthy controls (HCs) were enrolled. CD19⁺ B lymphocytes were isolated and purified using magnetic activated cell sorting (MACS). RNA was subsequently extracted from these cells and a small RNA library was created. The miRNA expression profile was analyzed using Beijing Genomics Institute Sequencing 500 (BGISEQ-500), and stem-loop real-time quantitative PCR (stem-loop qRT-PCR) was used to verify the sequencing results. Downstream target genes of the differentially expressed miRNAs were predicted using miRanda and TargetScan online software, and GO functional enrichment and pathway enrichment analyses were performed on these genes.

RESULTS

Compared with HCs, 178 upregulated and 143 downregulated miRNAs were identified in wAIHA patients, and stem-loop qRT-PCR of four randomly selected differentially expressed miRNAs verified the sequencing results. Ninety-five significantly enriched GO terms and eighty-five significantly enriched pathways were identified. Genes targeted by differentially expressed miRNAs were found to be mainly involved in the regulation of signal transduction, metabolic processes, immune reactions, and neoplastic disease development.

CONCLUSION

The expression of miRNAs in B lymphocytes from patients with primary wAIHA was deregulated, and this phenomenon may be involved in the pathogenesis of wAIHA.

Clear Cell Renal Carcinoma: MicroRNAs With Efficacy in Preclinical In Vivo Models

In order to identify new targets and treatment modalities for clear cell renal carcinoma, we surveyed the literature with respect to microRNAs involved in this disease. In this review, we have focused on up- and down-regulated miRs which mediate efficacy in preclinical clear-cell renal carcinoma-related in vivo models. We have identified 10 up-regulated and 33 down-regulated micro-RNAs according to this criterion. As proof-of-concept, micro-RNAs interfering with VEGF (miR-205p) and mTOR (mir-99a) pathways, which are modulated by approved drugs for this disease, have been identified. miRs targeting hypoxia induced factor-2α (HIF-2α) (miR-145), E3 ubiquitinylases speckle-type POZ protein (SPOP) (miR 520/372/373) and casitas B-lineage lymphoma (CBL) (miR-200a-3p), interfere with druggable targets. Further identified miRs interfere with cell-cycle dependent kinases, such as CDK2 (miR-200c), CDK4, 6 (miR-1) and CDK4, 9 (206c). Transmembrane receptor Ral interacting protein of 76 kD (RLIP76), targeted by mir-137, has emerged as another important target for ccRCC. Additional miRs and their targets merrying further preclinical validation are discussed.

CircRNA_100565 contributes to cisplatin resistance of NSCLC cells by regulating proliferation, apoptosis and autophagy via miR-337-3p/ADAM28 axis

Circular RNAs (circRNAs) have been revealed to involve in the chemoresistance of various cancers, including non-small cell lung cancer (NSCLC). Here, we further investigate the role of circRNA_100565 in NSCLC cisplatin (DDP) resistance. The expression of circRNA_100565 and microRNA (miR)-337-3p, and ADAM metallopeptidase domain 28 (ADAM28) mRNA was detected using quantitative real-time polymerase chain reaction. Cell viability and apoptosis were measured by cell counting kit-8 assay and flow cytometry, respectively. Western blot was used to detect the level of ADAM28 and autophagy-related protein. The interaction between miR-337-3p and circRNA_100565 or ADAM28 was confirmed by dual-luciferase reporter assay or pull-down assay. In vivo experiments were conducted via the murine xenograft model. We found CircRNA_100565 was up-regulated in NSCLC DDP-resistant tissues and cell lines, and its high expression was associated with shorter overall survival of NSCLC patients. CircRNA_100565 deletion mitigated DDP resistance, reflected by the suppression of proliferation and autophagy, the reduction of IC50 value, as well as enhancement of apoptosis in DDP-resistant NSCLC cells. MiR-377-3p was confirmed to directly bind to circRNA_100565 or ADAM28 3'-UTR. Moreover, circRNA_100565 indirectly regulated ADAM28 expression by sponging miR-377-3p in NSCLC cells. Additionally, circRNA_100565 deletion-induced sensitivity of NSCLC resistant cells to DDP could be remarkably attenuated by miR-377-3p inhibition or ADAM28 re-expression. Meanwhile, circRNA_100565 knockdown contributed to the anti-tumor effects of DDP on NSCLC in vivo.CONCLUSION: CircRNA_100565 was an independent prognostic factor for NSCLC patient survival, and enhanced the resistance of NSCLC cells to cisplatin by regulating cell proliferation, apoptosis and autophagy via miR-337-3p/ADAM28 axis, shedding light on the development of a novel therapeutic strategy to boost the effectiveness of NSCLC chemotherapy.

Carbonyl Reductase 3-Antisense RNA 1 Negatively Regulates microRNA-337-3p Expression: Effects on Proliferation, Migration, and Invasion of Lung Cancer Cells

Lung cancer, a malignant tumor, is associated with high morbidity and mortality worldwide. We studied the influence and mechanism of CBR3-AS1 on lung cancer cell proliferation, migration, and infiltration. The expression of CBR3-AS1 and miRNA-337-3p were higher and lower (P < 0.05), respectively, in lung cancer tissues than in paracancerous tissues. After inhibiting the expression of CBR3-AS1, the OD value of A549 cells, cloning formation numbers, migrating and invasive numbers, N-cadherin protein expression levels were lower. The G0-G1 cell cycle periods was longer. The S cell cycle periods was shorter. The E-cadherin protein expression levels higher (P < 0.05 in all cases). CBR3-AS1 negatively regulated miRNA-337-3p expression in A549 cells (P < 0.05). After inhibiting the expression of CBR3-AS1 and miRNA-337-3p, the OD value of A549 cells was lower, cloning formation numbers, migrating and invasive numbers, N-cadherin protein expression levels were lower. The G0-G1 cell cycle periods was longer. The S cell cycle periods was shorter. The E-cadherin protein expression levels was higher (P < 0.05 in all cases). CBR3-AS1 expression was increased in lung cancer tissues, and interference with CBR3-AS1 expression could inhibit the proliferation, migration, and infiltration of lung cancer A549 cells by negatively regulating miRNA-337-3p.

MiR-187 suppresses non-small-cell lung cancer cell proliferation by targeting FGF9

Non-small-cell lung cancer (NSCLC) is the main pathological type of lung cancer and has a low overall five-year survival rate. miR-187 has been reported to play major roles in various tumor types. In this study, we explored the impact of miR-187 on NSCLC. qRT-PCR results demonstrated that miR-187 expression is lower in NSCLC and cancer cells than normal tissues and normal lung cells. miR-187 expression levels are associated with tumor size, TNM stage and overall survival rate. MTS and colony formation assays showed that high miR-187 expression inhibits NSCLC cell proliferation and colony formation ability, and flow cytometry showed that miR-187 overexpression induces cell cycle arrest at the G0/G1 phase. A luciferase reporter assay showed that FGF9 is a target of miR-187. miR-187 overexpression reduces the expression of FGF9, cyclin D1 CDK4 and CDK6. Therefore, miR-187 may present a new NSCLC treatment target by regulates cyclins-related protein expression.

Chronic stress promotes EMT-mediated metastasis through activation of STAT3 signaling pathway by miR-337-3p in breast cancer

Chronic stress could induce cancer metastasis by constant activation of the sympathetic nervous system, while cellular mechanism remains obscure. The aim of this research is to explore the metastasis associated negative effect of chronic stress. The analysis of transcriptome sequencing implied that activation of STAT3 signaling pathway by downregulated miR-337-3p might be a potential mechanism to induce epithelial to mesenchymal transition (EMT) of cancer cell and promote metastasis under chronic stress. We also verified this biological process in further experiments. Downregulation of miR-337-3p could downregulate E-cadherin expression and upregulate vimentin expression in vitro and in vivo. STAT3, related signal pathways of which are involved in metastasis regulation, was directly targeted by miR-337-3p. In conclusion, the above results denoted that activation of miR-337-3p/STAT3 axis might be a potential pathway for the increasing metastasis of breast cancer under chronic stress.

Downregulation of circ_0132266 in chronic lymphocytic leukemia promoted cell viability through miR-337-3p/PML axis

Circular RNAs (circRNAs) have recently been reported to play crucial roles in various regulatory processes and involved in cancer onset and progression. However, the potential mechanism of circRNAs in chronic lymphocytic leukemia (CLL) remains largely unknown. Here, we observed hsa_circ_0132266 (circ_0132266), a circRNA significantly decreased in the peripheral blood mononuclear cells (PBMCs) of CLL patients compared with healthy donors, could act as an endogenous sponge of hsa-miR-337-3p (miR-337-3p) and regulate its activity, which resulted in a downstream change of target-gene PML and a consequent influence on cell viability. Taken together, our data indicated the regulatory mechanism of circ_0132266 in CLL progression through circ_0132266/miR-337-3p/PML axis, suggesting that it may serve as a biomarker as well as an exploitable therapeutic target for CLL.

Circ-calm4 Serves as an miR-337-3p Sponge to Regulate Myo10 (Myosin 10) and Promote Pulmonary Artery Smooth Muscle Proliferation

Pulmonary artery smooth muscle cell proliferation is the pathological basis of pulmonary vascular remodeling in hypoxic pulmonary hypertension. Recent studies suggest that circular RNA (circRNA) can regulate various biological processes, including cell proliferation. Therefore, it is possible that circRNA may have important roles in pulmonary artery smooth muscle cell proliferation in hypoxic pulmonary hypertension. In the present study, we aimed to identify functional circRNAs and clarify their roles and mechanisms in pulmonary artery smooth muscle cell proliferation in pulmonary hypertension. RNA sequencing identified 67 circRNAs that were differentially expressed in hypoxic lung tissues of mice. Screening by bioinformatics and quantitative polymerase chain reaction revealed significant elevation of a circRNA derived from alternative splicing of the calmodulin 4 gene (designated circ-calm4). Notably, this circRNA absorbed miR-337-3p. We further identified Myo10 (myosin 10) as a target protein of miR-337-3p. miR-337-3p bound to the 3'-untranslated region of Myo10 mRNA, thereby attenuating the translation of Myo10. Using loss-of-function and gain-of-function approaches, we found that circ-calm4 regulated cell proliferation by regulating the cell cycle. Additionally, we verified the functions of miR-337-3p and Myo10 in hypoxic pulmonary artery smooth muscle. Our results suggested that the circ-calm4/miR-337-3p/Myo10 signal transduction axis modulated the proliferation of pulmonary artery smooth muscle cells at the molecular level, thus establishing potential targets for the early diagnosis and treatment of pulmonary hypertension.

MiR-337-3p suppresses proliferation of epithelial ovarian cancer by targeting PIK3CA and PIK3CB

Epithelial ovarian cancer (EOC) is responsible for nearly 140,000 deaths worldwide each year. MicroRNAs play critical roles in cancer development and progression. The function of microRNA miR-337-3p has been described in various cancers. However, the biological role of miR-337-3p and its molecular mechanisms underlying EOC initiation and progression have not been reported. Here, we reported that the expression of miR-337-3p is down-regulated in EOC tissues and low expression of miR-337-3p is correlated with advanced pathological grade for patients. Ectopic expression of miR-337-3p inhibited proliferation and induced apoptosis and cell cycle arrest in G0/G1 phase of EOC cells. PIK3CA and PIK3CB were revealed to be direct targets of miR-337-3p for reducing the activation of PI3K/AKT signaling pathway. PIK3CA and PIK3CB were discovered to affect cell proliferation of EOC cells in combination, and only when overexpressed simultaneously in miR-337-3p-expressing cells, could fully restore cell proliferation. In vivo investigation confirmed that miR-337-3p is a tumor suppressor that control expression of PIK3CA and PIK3CB encoded protein: p110α and p110β. Altogether, our results demonstrate that miR-337-3p is a tumor suppressor in EOC that inhibits the expression of PIK3CA and PIK3CB.

Inhibition of miR-337-3p involved in the protection of CoCl2 -induced injury in PC12 cells via activating JAK2/STAT3 signaling pathway

OBJECTIVE

To investigate the possibility of microRNA (miR)-337-3p in the protection of hypoxia-induced injury in PC12 cells via modulating the JAK2/STAT3 signaling pathway.

METHODS

Dual-luciferase reporter assay analyzed the relationship between the miR-337-3p and JAK2. PC12 cells were divided into normal, CoCl₂ , CoCl2 + NC, CoCl2 + inhibitors, CoCl2 + JAK2, and CoCl2 + mimics + JAK2 groups. Then, PC12 cell viability and apoptosis were measured by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and Annexin-V-fluorescein isothiocyanate/propidium iodide methods. Quantitative real-time polymerase chain reaction and Western blot analysis were used to determine expressions. Besides, the intracellular reactive oxygen species (ROS) was examined by dichloro-dihydro-fluorescein diacetate (DCFH-DA) while the mitochondrial membrane potential (MMP) by using JC-1.

RESULTS

The negative targeting relationship between miR-337-3p and JAK2 was confirmed. When compared with the normal group, miR-337-3p was increased while JAK2 and STAT3 were decreased in CoCl₂ -induced PC12 cells, with decreased cell viability. Moreover, either miR-337-3p inhibitor or JAK2 overexpression could partially reverse CoCl₂ -induced decrease in PC12 cell viability. Besides, CoCl₂ could also trigger PC12 cell apoptosis by increasing cleaved caspase 3 and Bax but decreasing Bcl-2 and Bcl-XL, which, however, were abolished with the transfection of miR-337-3p inhibitors or lentivirus transfection to activate JAK2. Compared with the CoCl₂ group, the average of fluorescent signals of ROS in the CoCl2 + inhibitors group and the CoCl2 + JAK2 group was lower, while the activities of superoxide dismutase, catalase, glutathione peroxidase, and total anti-oxidative capacity were higher, together with an increase in MMP.

CONCLUSION

Inhibiting miR-337-3p could activate the JAK2/STAT3 signaling pathway to suppress CoCl ₂ -induced cytotoxicity and apoptosis and ameliorate oxidative stress and MMP in PC12 cells.