scholarly journals Downregulation of miR-1-3p expression inhibits the hypertrophy and mineralization of chondrocytes in DDH

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Rui Ding ◽  
Xijuan Liu ◽  
Jian Zhang ◽  
Jinghong Yuan ◽  
Sikuan Zheng ◽  
...  
Keyword(s):  
Animal Model ◽  
Target Genes ◽  
Collagen Type ◽  
Developmental Dysplasia ◽  
Luciferase Reporter ◽  
Acetabular Roof ◽  
Western Blots ◽  
Alizarin Red ◽  
Low Expression

Abstract Background Developmental dysplasia of the hip (DDH) is a highly prevalent hip disease among children. However, its pathogenesis remains unclear. MicroRNAs (miRNA) are important regulators of cartilage development. In a previous study, high-throughput miRNA sequencing of tissue samples from an animal model of DDH showed a low level of miR-1-3p in the cartilage of the acetabular roof (ARC), but its role in DDH pathogenesis was not addressed. Therefore, our aim here was to investigate the effects of miR-1-3p in the ARC. Methods The diagnosis of acetabular dysplasia was confirmed with X-ray examination, while imaging and HE staining were conducted to further evaluate the ARC thickness in each animal model. FISH was employed to verify miR-1-3p expression in the ARC and chondrocytes. The miR-1-3p target genes were predicted by a bioinformatics database. A dual-luciferase reporter assay was used to confirm the targeting relationship between miR-1-3p and SOX9. The gene expression of miR-1-3p, SOX9, RUNX2 and collagen type X was evaluated by qPCR analysis. The protein expression of SOX9, RUNX2 and collagen type X was detected by western blot analysis. The levels of SOX9, RUNX2, and collagen type X in the ARC were further assessed via immunohistochemistry analysis. Finally, Alizarin Red S staining was used to observe the mineralized nodules produced by the chondrocytes. Results We observed low expression of miR-1-3p in the ARC of animals with DDH. SOX9 is a miR-1-3p target gene. Using miR-1-3p silencing technology in vitro, we demonstrated significantly reduced chondrocyte-generated mineralized nodules compared to those of the control. We also confirmed that with miR-1-3p silencing, SOX9 expression was upregulated, whereas the expression of genes associated with endochondral osteogenesis such as RUNX2 and collagen type X was downregulated. To confirm the involvement of miR-1-3p silencing in abnormal ossification through SOX9, we also performed a rescue experiment in which SOX9 silencing restored the low expression of RUNX2 and collagen type X produced by downregulated miR-1-3p expression. Finally, the elevated SOX9 levels and reduced RUNX2 and collagen type X levels in the ARC of rabbits with DDH were also verified using immunohistochemistry, RT-PCR, and western blots. Conclusion The relatively low expression of miR-1-3p in the ARC may be the cause of abnormal endochondral ossification in the acetabular roof of animals with DDH.

scholarly journals MiR-1-3p Downregulation Delays Endochondral Ossification of the Acetabular Roof in DDH

2021 ◽  
Author(s):  
Rui Ding ◽  
xijuan liu ◽  
jian zhang ◽  
jinghong yuan ◽  
sikuan zheng ◽  
...  
Keyword(s):  
Animal Model ◽  
Western Blot ◽  
Endochondral Ossification ◽  
Target Gene ◽  
Collagen Type ◽  
Luciferase Reporter ◽  
Acetabular Roof ◽  
Alizarin Red ◽  
Gene Assay ◽  
Low Expression

Abstract Background: Developmental dysplasia of the hip (DDH) is a highly prevalent hip disease among children. However, its pathogenesis remains unclear. MiRNAs are important regulators in cartilage development. In previous study, miRNA high-throughput sequencing on an animal model of DDH showed a low level of miR-1-3p in the cartilage of acetabular roof (ARC), but its role in DDH pathogenesis was not addressed. Therefore, our aim was to investigate the effects of miR-1-3p in the ARC.Methods: The X-ray examination was performed to confirm acetabular dysplasia, MRI imaging and HE staining was conducted to further evaluate the ARC thickness in each animal model. The FISH was used to confirm the expression of miR-1-3p in the ARC and chondrocytes. The target gene of miR-1-3p was predicted by bioinformatics database. The dual-luciferase reporter gene assay was used to confirm the targeting relationship between miR-1-3p and SOX9. The gene expression of miR-1-3p, SOX9, RUNX2 and collagen type X by QPCR analysis. The relative proteins level was detected by western blot analysis. The level of SOX9, RUNX2 and collagen type X in the ARC through immunohistochemistry analysis. Alizarin Red S staining was used to observe the mineralized nodules produced by chondrocytes.Results: The low expression of miR-1-3p in the ARC of DDH. SOX9 is miR-1-3p target gene. Downregulation the expression of miR-1-3p in vitro and demonstrated significantly reduced chondrocytes generated mineralized nodules, as opposed to the control. We also confirmed that, with miR-1-3p silencing, SOX9 expression was upregulated, whereas expression of genes associated with endochondral osteogenesis RUNX2 and collagen type X were downregulated. To confirm the involvement of miR-1-3p silencing in abnormal ossification through SOX9, we also performed a rescue experiment where SOX9 silencing restored the low expression of RUNX2 and collagen type X, produced by miR-1-3p downregulation. Lastly, the elevated SOX9 levels and reduced RUNX2 and collagen type X levels in the ARC of DDH rabbits were also verified, using immunohistochemistry, RT-PCR, and western blot. Conclusion: The low expression of mir-1-3p in the ARC of DDH, which may be the cause of the acetabular roof abnormal endochondral ossification in DDH.

scholarly journals Circular RNA circSDHC serves as a sponge for miR-127-3p to promote the proliferation and metastasis of renal cell carcinoma via the CDKN3/E2F1 axis

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Junjie Cen ◽  
Yanping Liang ◽  
Yong Huang ◽  
Yihui Pan ◽  
Guannan Shu ◽  
...  
Keyword(s):  
Renal Cell Carcinoma ◽  
Cell Carcinoma ◽  
Renal Cell ◽  
Target Genes ◽  
Expression Patterns ◽  
Luciferase Reporter ◽  
Circular Rnas ◽  
Proliferation And Metastasis

Abstract Background There is increasing evidence that circular RNAs (circRNAs) have significant regulatory roles in cancer development and progression; however, the expression patterns and biological functions of circRNAs in renal cell carcinoma (RCC) remain largely elusive. Method Bioinformatics methods were applied to screen for circRNAs differentially expressed in RCC. Analysis of online circRNAs microarray datasets and our own patient cohort indicated that circSDHC (hsa_circ_0015004) had a potential oncogenic role in RCC. Subsequently, circSDHC expression was measured in RCC tissues and cell lines by qPCR assay, and the prognostic value of circSDHC evaluated. Further, a series of functional in vitro and in vivo experiments were conducted to assess the effects of circSDHC on RCC proliferation and metastasis. RNA pull-down assay, luciferase reporter and fluorescent in situ hybridization assays were used to confirm the interactions between circSDHC, miR-127-3p and its target genes. Results Clinically, high circSDHC expression was correlated with advanced TNM stage and poor survival in patients with RCC. Further, circSDHC promoted tumor cell proliferation and invasion, both in vivo and in vitro. Analysis of the mechanism underlying the effects of circSDHC in RCC demonstrated that it binds competitively to miR-127-3p and prevents its suppression of a downstream gene, CDKN3, and the E2F1 pathway, thereby leading to RCC malignant progression. Furthermore, knockdown of circSDHC caused decreased CDKN3 expression and E2F1 pathway inhibition, which could be rescued by treatment with an miR-127-3p inhibitor. Conclusion Our data indicates, for the first time, an essential role for the circSDHC/miR-127-3p/CDKN3/E2F1 axis in RCC progression. Thus, circSDHC has potential to be a new therapeutic target in patients with RCC.

MiR-30a-5p Downregulation Induces Neuronal Autophagy by Activating AMPK After 2856MHz Microwave Radiation

2021 ◽  
Author(s):  
Yanhui Hao ◽  
Wenchao Li ◽  
Hui Wang ◽  
Jing Zhang ◽  
Haoyu Wang ◽  
...  
Keyword(s):  
Microwave Radiation ◽  
Hippocampal Neurons ◽  
Target Genes ◽  
Neuronal Damage ◽  
Luciferase Reporter ◽  
Potential Health ◽  
Downstream Target ◽  
Neuronal Autophagy

Abstract Background With the development of science and technology, microwaves are being widely used. More and more attention has been paid to the potential health hazards of microwave exposure. The regulation of miR-30a-5p (miR-30a) on autophagy is involved in the pathophysiological process of many diseases. Our previous study found that 30 mW/cm2 microwave radiation could reduce miR-30a expression and activate neuronal autophagy in rat hippocampus. However, the roles played by miR-30a in microwave-induced neuronal autophagy and related mechanisms remain largely unexplored. Results In the present study, we established neuronal damage models by exposing rat hippocampal neurons and rat adrenal pheochromocytoma (PC12) cell-derived neuron-like cells to 30 mW/cm2 microwave, which resulted in miR-30a downregulation and autophagy activation in vivo and in vitro. Bioinformatics analysis was conducted, and Beclin1, Prkaa2, Irs1, Pik3r2, Rras2, Ddit4, Gabarapl2 and autophagy-related gene 12 (Atg12) were identified as potential downstream target genes of miR-30a involved in regulating autophagy. Based on our previous findings that microwave radiation can cause a neuronal energy metabolism disorder, Prkaa2, encoding adenosine 5’-monophosphate-activated protein kinase α2 (AMPKα2, an important catalytic subunit of energy sensor AMPK), was selected for further analysis. Dual-luciferase reporter assay results showed that Prkaa2 is a downstream target gene of miR-30a. Microwave radiation increased the expression and phosphorylation (Thr172) of AMPKα both in vivo and in vitro. Moreover, the transduction of cells with miR-30a mimics suppressed AMPKα2 expression, inhibited AMPKα (Thr172) phosphorylation and reduced autophagy flux in neuron-like cells. Importantly, miR-30a mimics abolished microwave-activated autophagy and inhibited microwave-induced AMPKα (Thr172) phosphorylation. Conclusions AMPKα2 was a newly founded downstream gene of miR-30a involved in autophagy regulation, and miR-30a downregulation after microwave radiation could promote neuronal autophagy by increasing AMPKα2 expression and activating AMPK signaling.

scholarly journals LukS-PV-Regulated MicroRNA-125a-3p Promotes THP-1 Macrophages Differentiation and Apoptosis by Down-Regulating NF1 and Bcl-2

2017 ◽  
Vol 44 (3) ◽  
pp. 1093-1105 ◽  
Author(s):  
Xiao-Xi Sun ◽  
Shan-Shan Zhang ◽  
Chun-Yang Dai ◽  
Jing Peng ◽  
Qing Pan ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Cellular Differentiation ◽  
Target Genes ◽  
B Cell Lymphoma ◽  
Neurofibromatosis Type ◽  
Luciferase Reporter ◽  
Loss Of Function ◽  
Leukaemia Cell Line ◽  
Reporter Assays

Background/Aims: LukS-PV is a component of Panton-Valentine leukocidin (PVL). We have previously demonstrated that LukS-PV potently promoted differentiation and induced apoptosis in THP-1 cells. However, the precise mechanisms of these actions remain unknown. MicroRNAs (miRs) play important roles in cellular differentiation and apoptosis. This study aimed to investigate the role of miR-125a-3p in LukS-PV-regulated differentiation and apoptosis and its underlying mechanism in THP-1 cells. Methods: MicroRNA profiling analyses were conducted to determine differential miRNA expression levels in THP-1 cells treated with LukS-PV. Cell differentiation and apoptosis were measured in THP-1 cells by gain-of-function and loss-of-function experiments. Bioinformatics analysis and luciferase reporter assays were used to confirm the targets of miR-125a-3p. The effects of the miR-125a-3p targets on cellular differentiation were determined by knocking them down. Results: MiR-125a-3p was up-regulated after treating the human monocytic leukaemia cell line THP-1 with LukS-PV. In addition, miR-125a-3p positively regulated apoptosis and differentiation in THP-1 cells treated with LukS-PV. Concordantly, luciferase reporter assays confirmed that neurofibromatosis type 1 (NF1) and B-cell lymphoma 2 (Bcl-2) were direct target genes of miR-125a-3p. Moreover, NF1 knockdown in THP-1 cells significantly promoted differentiation in vitro. Finally, the extracellular signal-regulated kinase (ERK) pathway, a downstream target of NF1, was activated after NF1 knockdown. Conclusions: These findings confirm that miR-125a-3p is involved in LukS-PV-mediated cell differentiation and apoptosis in THP-1 cells.

scholarly journals Cell culture-derived HCV cannot infect synovial fibroblasts

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Dina N. Abd-Elshafy ◽  
Thomas Pietschmann ◽  
Ulf Müller-Ladner ◽  
Elena Neumann ◽  
Anggakusuma ◽  
...  
Keyword(s):  
Cell Culture ◽  
Hepatitis C ◽  
Synovial Fibroblasts ◽  
Luciferase Reporter ◽  
Synovial Cells ◽  
Significant Extent ◽  
Subgenomic Replicon ◽  
Immune Mediated ◽  
Low Expression

Abstract Worldwide 170 million individuals are infected with hepatitis C virus (HCV), up to 45 million of whom are affected by arthropathy. It is unclear whether this is due to viral infection of synovial cells or immune-mediated mechanisms. We tested the capacity of primary synovial fibroblasts to support HCV propagation. Out of the four critical HCV receptors, only CD81 was expressed to any significant extent in OASF and RASF. Consistent with this, pseudotyped HCV particles were unable to infect these cells. Permissiveness for HCV replication was investigated by transfecting cells with a subgenomic replicon of HCV encoding a luciferase reporter. OASF and RASF did not support replication of HCV, possibly due to low expression levels of miR-122. In conclusion, primary human synovial fibroblasts are unable to support propagation of HCV in vitro. HCV-related arthropathy is unlikely due to direct infection of these cells.

scholarly journals SIRT6 Promotes Osteogenic Differentiation of Adipose-Derived Mesenchymal Stem Cells Through Antagonizing DNMT1

2021 ◽  
Vol 9 ◽  
Author(s):  
Bo Jia ◽  
Jun Chen ◽  
Qin Wang ◽  
Xiang Sun ◽  
Jiusong Han ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Stem Cells ◽  
Notch Signaling ◽  
Osteogenic Differentiation ◽  
Dna Methyltransferases ◽  
Luciferase Reporter ◽  
Calcium Deposition ◽  
Alizarin Red

BackgroundAdipose-derived stem cells (ADSCs) are increasingly used in regenerative medicine because of their potential to differentiate into multiple cell types, including osteogenic lineages. Sirtuin protein 6 (SIRT6) is a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase that plays important roles in cell differentiation. NOTCH signaling has also been reported to involve in osteogenic differentiation. However, the function of SIRT6 in osteogenic differentiation of ADSCs and its relation to the NOTCH signaling pathways are yet to be explored.MethodsThe in vitro study with human ADSCs (hADSCs) and in vivo experiments with nude mice have been performed. Alkaline phosphatase (ALP) assays and ALP staining were used to detect osteogenic activity. Alizarin Red staining was performed to detect calcium deposition induced by osteogenic differentiation of ADSCs. Western blot, RT-qPCR, luciferase reporter assay, and co-immunoprecipitation assay were applied to explore the relationship between of SIRT6, DNA methyltransferases (DNMTs) and NOTCHs.ResultsSIRT6 promoted ALP activity, enhanced mineralization and upregulated expression of osteogenic-related genes of hADSCs in vitro and in vivo. Further mechanistic studies showed that SIRT6 deacetylated DNMT1, leading to its unstability at protein level. The decreased expression of DNMT1 prevented the abnormal DNA methylation of NOTCH1 and NOTCH2, resulting in the upregulation of their transcription. SIRT6 overexpression partially suppressed the abnormal DNA methylation of NOTCH1 and NOTCH2 by antagonizing DNMT1, leading to an increased capacity of ADSCs for their osteogenic differentiation.ConclusionThis study demonstrates that SIRT6 physical interacts with the DNMT1 protein, deacetylating and destabilizing DNMT1 protein, leading to the activation of NOTCH1 and NOTCH2, Which in turn promotes the osteogenic differentiation of ADSCs.

scholarly journals Decreased miR-4512 Levels in Monocytes and Macrophages of Individuals With Systemic Lupus Erythematosus Contribute to Innate Immune Activation and Neutrsophil NETosis by Targeting TLR4 and CXCL2

2021 ◽  
Vol 12 ◽  
Author(s):  
Binbin Yang ◽  
Xinwei Huang ◽  
Shuangyan Xu ◽  
Li Li ◽  
Wei Wu ◽  
...  
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Lupus Erythematosus ◽  
Target Genes ◽  
Mononuclear Cells ◽  
Therapeutic Potential ◽  
Luciferase Reporter ◽  
Systemic Lupus ◽  
Peripheral Blood Mononuclear ◽  
Monocytes And Macrophages

ObjectiveSystemic lupus erythematosus (SLE) is an autoimmune disease with complex etiology that is not yet entirely understood. We aimed to elucidate the mechanisms and therapeutic potential of microRNAs (miRNAs) in SLE in a Tibetan population.MethodsPeripheral blood mononuclear cells from SLE patients (n = 5) and healthy controls (n = 5) were used for miRNA–mRNA co-sequencing to detect miRNAs related to immune abnormalities associated with SLE. Luciferase reporter assay was used to identify potential targets of candidate miRNA. The target genes were verified in miRNA-agomir/antagomir transfection assays with multiple cells lines and by expression analysis. The effects of candidate miRNA on monocyte and macrophage activation were evaluated by multiple cytokine profiling. Neutrophil extracellular traps (NETs) formation was analyzed in vitro by cell stimulation with supernatants of monocytes and macrophages transfected with candidate miRNA. The rodent MRL/lpr lupus model was used to evaluate the therapeutic effect of CXCL2Ab on SLE and the regulation effect of immune disorders.ResultsIntegrated miRNA and mRNA expression profiling identified miRNA-4512 as a candidate miRNA involved in the regulation of neutrophil activation and chemokine-related pathways. MiR-4512 expression was significantly reduced in monocytes and macrophages from SLE patients. MiR-4512 suppressed the TLR4 pathway by targeting TLR4 and CXCL2. Decreased monocyte and macrophage miR-4512 levels led to the expression of multiple proinflammatory cytokines in vitro. Supernatants of miR-4512 antagomir-transfected monocytes and macrophages significantly promoted NETs formation (P < 0.05). Blocking of CXCL2 alleviated various pathogenic manifestations in MRL/lpr mice, including kidney damage and expression of immunological markers of SLE.ConclusionsWe here demonstrated the role of miR-4512 in innate immunity regulation in SLE. The effect of miR-4512 involves the regulation of monocytes, macrophages, and NETs formation by direct targeting of TLR4 and CXCL2, indicating the miR-4512-TLR4-CXCL2 axis as a potential novel therapeutic target in SLE.

scholarly journals LncRNA MALAT1: A potential therapeutic target in DSSinduced ulcerative colitis progression in vitro

2020 ◽  
Vol 19 (9) ◽  
pp. 1871-1877
Author(s):  
Baoqin Zhang ◽  
Tiantian Li ◽  
Chao Wang ◽  
Jing Han ◽  
Baiqing Wang ◽  
...  
Keyword(s):  
Ulcerative Colitis ◽  
Therapeutic Target ◽  
Target Genes ◽  
Severe Disease ◽  
Luciferase Reporter ◽  
Mucosal Cell ◽  
Gene Expressions ◽  
Lncrna Malat1 ◽  
Liver Cancers

Purpose: Ulcerative colitis is a severe disease affecting human health worldwide. Studies have shown that lncRNA MALAT1 has a significant correlation with breast, pancreatic, colon and liver cancers, but its effects on colitis is yet to be discovered. In this study, the potential role of lncRNA MALAT1 and the underlying molecular mechanism in DSS-induced colitis were investigated in vitro.Methods: Colorectal mucosal cell line FHC was induced with dextran sulphate sodium (DSS) to form an in vitro colitis model. Transfection procedure was employed to up- or down-regulate the expressions of lncRNA MALAT1 or miR-30c-5p in FHC cells. Cell viabilities were detected by CCK-8 assay. RT-qPCR was applied for evaluating gene expressions in normal FHC and DSS-induced FHC cell lines, while protein expression levels of target genes were examined by Western blot analysis. Starbase was used to predict the molecular interaction between MALAT1 and miR-30c-5p, while luciferase reporter assay was utilized to verify the binding sites between the two genes.Results: Expression of MALAT1 in the DSS-induced FHC cells was high with low cell viabilities, compared to the normal FHC cells. In the DSS-induced colitis-like FHC cells, overexpression of MALAT1 inhibited cell viabilities, while its downregulation promoted it. MiR-30c-5p directly targets MALAT1 and inhibited its expression in DSS-treated FHC cells. Upregulation of miR-30c-5p increased cell viabilities. Bcl-xL expression was inhibited by the up-regulation of MALAT1, while that of Bax was enhanced and the mimics of miR-30c-5p reversed these observations, suggesting that the enhancement of apoptosis promoted by oe-MALAT1 could be inhibited by miR-30c-5p. The interaction between MALAT1 and miR-30c-5p regulated NF-κB/TGF-β/Wnt-β-catenin signaling pathway.Conclusion: Overexpression of MALAT1 led to inhibition of cell viability, while apoptosis and inflammation were promoted by targeting miR-30c-5p via NF-κB/TGF-β/Wnt-β-catenin signaling pathway. These findings suggest MALAT1 as a therapeutic target for treating colitis. Keywords: Colitis, MALAT1, miR-30c-5p, NF-κB/TGF-β/Wnt-β-catenin 

scholarly journals MiR-130a-3p Regulates the Glycolysis via Targeting PDK1 in Hepatocellular Carcinoma

2021 ◽  
Author(s):  
Hai-Long Li ◽  
Jie Shi ◽  
Qi Qi ◽  
Yue Huang ◽  
Chi Liu ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Glucose Metabolism ◽  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Kinase ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
And Migration ◽  
Low Expression ◽  
Hcc Cells

Abstract MiR-130a-3p has been certified to have low expression in several types of tumors. However, the function of miR-130a-3p in glucose metabolism and hepatocellular carcinoma progression is still elusive. Here we report that miR-130a-3p has explicitly low expression in human HCC tissues and cells and is closely related to the patient's tumor size and grade. Overexpression of miR-130a-3p significantly inhibits the glucose metabolism, proliferation and migration of HCC cells in vitro. In order to further study the effects of miR-130a-3p in the glucose metabolism of HCC cells, we found that overexpression of miR-130a-3p significantly inhibited the expression of pyruvate dehydrogenase kinase 1 (PDK1). Consistently, we confirmed that PDK1 is the target gene of miR-130a-3p through dual luciferase reporter gene assays. Cell rescue experiments showed that PDK1 inhibitors reversed the enhancement of cell proliferation, migration and glucose metabolism by miR-130a-3p inhibitor in Hep3B cells. In terms of mechanism, overexpression of miR-130a-3p targeted and inhibited the expression of PDK1, after which pyruvate dehydrogenase (PDH) is activated, thus glycolysis is inhibited, the production of lactic acid and ATP is reduced, and the ability to proliferate and migrate in HCC cells is weakened. In conclusion, our study highlights efforts to target PDK1 and miR-130a-3p as potential therapeutic strategies for the treatment of HCC.

scholarly journals MicroRNA-34a Attenuates Paclitaxel Resistance in Prostate Cancer Cells via Direct Suppression of JAG1/Notch1 Axis

2018 ◽  
Vol 50 (1) ◽  
pp. 261-276 ◽  
Author(s):  
Xiaobing Liu ◽  
Xing Luo ◽  
Yuqi Wu ◽  
Ding Xia ◽  
Wei Chen ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Tumor Growth ◽  
Western Blot ◽  
Target Genes ◽  
Luciferase Reporter Assay ◽  
Luciferase Reporter ◽  
Reporter Assay ◽  
Qrt Pcr

Background/Aims: Treatment options for metastatic castrate-resistant prostate cancer (mCRPC) are limited and typically centered on paclitaxel-based chemotherapy. In this study, we aimed to evaluate whether miR-34a attenuates chemoresistance to paclitaxel by regulating target genes associated with drug resistance. Methods: We used data from The Cancer Genome Atlas to compare miR-34a expression levels in prostate cancer (PC) tissues with normal prostate tissues. The effects of miR-34a inhibition and overexpression on PC proliferation were evaluated in vitro via Cell Counting Kit-8 (CCK-8) proliferation, colony formation, apoptosis, and cell-cycle assays. A luciferase reporter assay was employed to identify the interactions between miR-34a and specific target genes. To determine the effects of up-regulation of miR-34a on tumor growth and chemo-resistance in vivo, we injected PC cells overexpressing miR-34a into nude mice subcutaneously and evaluated the rate of tumor growth during paclitaxel treatment. We examined changes in the expression levels of miR-34a target genes JAG1 and Notch1 and their downstream genes via miR-34a transfection by quantitative reverse transcription PCR (qRT-PCR) and western blot assay. Results: miR-34a served as an independent predictor of reduced patient survival. MiR-34a was down-regulated in PC-3PR cells compared with PC-3 cells. The CCK-8 assay showed that miR-34a overexpression resulted in increased sensitivity to paclitaxel while miR-34a down-regulation resulted in chemoresistance to paclitaxel in vitro. A study of gain and loss in a series of functional assays revealed that PC cells expressing miR-34a were chemosensitive. Furthermore, the overexpression of miR-34a increased the sensitivity of PC-3PR cells to chemotherapy in vivo. The luciferase reporter assay confirmed that JAG1 and Notch1 were directly targeted by miR-34a. Interestingly, western blot analysis and qRT-PCR confirmed that miR-34a inhibited the Notch1 signaling pathway. We found that miR-34a increased the chemosensitivity of PC-3PR cells by directly repressing the TCF1/ LEF1 axis. Conclusion: Our results showed that miR-34a is involved in the development of chemosensitivity to paclitaxel. By regulating the JAG1/Notch1 axis, miR-34a or its target genes JAG1 or Notch1 might serve as potential predictive biomarkers of response to paclitaxel-based chemotherapy and/or therapeutic targets that will help to overcome chemoresistance at the mCRPC stage.

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