Long Non-coding RNA PCED1B Antisense RNA 1 Promotes Cell Proliferation and Invasion in Hepatocellular Carcinoma by Regulating the MicroRNA-34a/CD44 Axis.

OBJECTIVE: This study aimed to examine the role of long non-coding RNA PCED1B antisense RNA 1 (PCED1B-AS1) in the development of hepatocellular carcinoma (HCC). METHODS: A total of 62 pairs of HCC tissues and adjacent non-tumor tissues were obtained from 62 HCC patients. The interactions of PCED1B-AS1 and microRNA-34a (miR-34a) were detected by dual luciferase activity assay and RNA pull-down assay. The RNA expression levels of PCED1B-AS1, miR-34a and CD44 were detected by RT-qPCR, and the protein expression level of CD44 was determined by Western blotting. The cell proliferation was detected by cell proliferation assay, and the cell invasion and migration by transwell invasion assay. The HCC tumor growth after PCED1B-AS1 was downregulated was determined by in vivo animal study. RESULTS: PCED1B-AS1 was highly expressed in HCC tissues, which was associated with poor survival of HCC patients. Furthermore, PCED1B-AS1 interacted with miR-34a in HCC cells, but they did not regulate the expression of each other. Additionally, PCED1B-AS1 increased the expression level of CD44, which was targeted by miR-34a. The cell proliferation and invasion assay revealed that miR-34a inhibited the proliferation and invasion of HCC in vitro, while CD44 exhibited the opposite effects. Furthermore, PCED1B-AS1 suppressed the role of miR-34a. Moreover, the knockdown of PCED1B-AS1 repressed the HCC tumor growth in nude mice in vivo. CONCLUSION: PCED1B-AS1 may play an oncogenic role by regulating the miR-34a/CD44 axis in HCC.

Long non­coding RNA lung cancer­associated transcript 1 regulates ferroptosis via microRNA­34a­5p­mediated GTP cyclohydrolase 1 downregulation in lung cancer cells.

Ferroptosis, a recently discovered type of programmed cell death triggered by excessive accumulation of iron­dependent lipid peroxidation, is linked to several malignancies, including non­small cell lung cancer. Long non­coding RNAs (lncRNAs) are involved in ferroptosis; however, data on their role and mechanism in cancer therapy remains limited. Therefore, the aim of the present study was to identify ferroptosis­associated mRNAs and lncRNAs in A549 lung cancer cells treated with RAS­selective lethal 3 (RSL3) and ferrostatin­1 (Fer­1) using RNA sequencing. The results demonstrated that lncRNA lung cancer­associated transcript 1 (LUCAT1) was significantly upregulated in lung adenocarcinoma and lung squamous cell carcinoma tissues. Co­expression analysis of differentially expressed mRNAs and lncRNAs suggested that LUCAT1 has a crucial role in ferroptosis. LUCAT1 expression was markedly elevated in A549 cells treated with RSL3, which was prevented by co­incubation with Fer­1. Functionally, overexpression of LUCAT1 facilitated cell proliferation and reduced the occurrence of ferroptosis induced by RSL3 and Erastin, while inhibition of LUCAT1 expression reduced cell proliferation and increased ferroptosis. Mechanistically, downregulation of LUCAT1 resulted in the downregulation of both GTP cyclohydrolase 1 (GCH1) and ferroptosis suppressor protein 1 (FSP1). Furthermore, inhibition of LUCAT1 expression upregulated microRNA (miR)­34a­5p and then downregulated GCH1. These results indicated that inhibition of LUCAT1 expression promoted ferroptosis by modulating the downregulation of GCH1, mediated by miR­34a­5p. Therefore, the combination of knocking down LUCAT1 expression with ferroptosis inducers may be a promising strategy for lung cancer treatment.

Long Non-coding RNA X-Inactive Specific Transcript Promotes Esophageal Squamous Cell Carcinoma Progression via the MicroRNA 34a/Zinc Finger E-box-Binding Homeobox 1 Pathway.

BACKGROUND: The long non-coding RNA X-inactive specific transcript (XIST) plays a crucial role in transcriptional silencing of the X chromosome. Zinc finger E-box-binding homeobox 1 (ZEB1) is a transcription factor involved in epithelial-mesenchymal transition (EMT) regulation. AIMS: This study aimed to investigate the impact of XIST on esophageal squamous cell carcinoma (ESCC) progression and its underlying mechanism involving the miR-34a/ZEB1/E-cadherin/EMT pathway. METHODS: XIST and ZEB1 expression were analyzed using quantitative PCR and immunohistochemistry. XIST knockdown was achieved in KYSE150 ESCC cells using siRNA or shRNA lentivirus transfection. Proliferation, migration, and invasion abilities were assessed, and luciferase reporter assays were performed to confirm XIST-miR-34a-ZEB1 interactions. In vivo ESCC growth was evaluated using a xenograft mouse model. RESULTS: XIST and ZEB1 were upregulated in tumor tissues, correlating with metastasis and reduced survival. XIST knockdown inhibited proliferation, migration, and invasion of KYSE150 cells. It decreased ZEB1 expression, increased E-cadherin and miR-34a levels. Luciferase reporter assays confirmed miR-34a binding to XIST and ZEB1. XIST knockdown suppressed xenograft tumor growth. CONCLUSION: XIST promotes ESCC progression via the miR-34a/ZEB1/E-cadherin/EMT pathway. Targeting the XIST/miR-34a/ZEB1 axis holds therapeutic potential and serves as a prognostic biomarker in ESCC.

Developing Folate-Conjugated miR-34a Therapeutic for Prostate Cancer: Challenges and Promises.

Prostate cancer (PCa) remains a common cancer with high mortality in men due to its heterogeneity and the emergence of drug resistance. A critical factor contributing to its lethality is the presence of prostate cancer stem cells (PCSCs), which can self-renew, long-term propagate tumors, and mediate treatment resistance. MicroRNA-34a (miR-34a) has shown promise as an anti-PCSC therapeutic by targeting critical molecules involved in cancer stem cell (CSC) survival and functions. Despite extensive efforts, the development of miR-34a therapeutics still faces challenges, including non-specific delivery and delivery-associated toxicity. One emerging delivery approach is ligand-mediated conjugation, aiming to achieve specific delivery of miR-34a to cancer cells, thereby enhancing efficacy while minimizing toxicity. Folate-conjugated miR-34a (folate-miR-34a) has demonstrated promising anti-tumor efficacy in breast and lung cancers by targeting folate receptor α (FOLR1). Here, we first show that miR-34a, a TP53 transcriptional target, is reduced in PCa that harbors TP53 loss or mutations and that miR-34a mimic, when transfected into PCa cells, downregulated multiple miR-34a targets and inhibited cell growth. When exploring the therapeutic potential of folate-miR-34a, we found that folate-miR-34a exhibited impressive inhibitory effects on breast, ovarian, and cervical cancer cells but showed minimal effects on and targeted delivery to PCa cells due to a lack of appreciable expression of FOLR1 in PCa cells. Folate-miR-34a also did not display any apparent effect on PCa cells expressing prostate-specific membrane antigen (PMSA) despite the reported folate's binding capability to PSMA. These results highlight challenges in the specific delivery of folate-miR-34a to PCa due to a lack of target (receptor) expression. Our study offers novel insights into the challenges and promises within the field and casts light on the development of ligand-conjugated miR-34a therapeutics for PCa.

Oligochitosan-based nanovesicles for nonalcoholic fatty liver disease treatment via the FXR/miR-34a/SIRT1 regulatory loop.

Non-alcoholic fatty liver disease (NAFLD) is currently a common chronic liver disease worldwide. By now, however, there isn't any FDA-approved specific drug for NAFLD treatment. It has been noticed that farnesoid X receptor (FXR), miR-34a and Sirtuin1 (SIRT1) is related to the occurrence and development of NAFLD. A oligochitosan-derivated nanovesicle (UBC) with esterase responsive degradability was designed to co-encapsulate FXR agonist (obeticholic acid, OCA) and miR-34a antagomir (anta-miR-34a) into the hydrophobic membrane and the center aqueous lumen of nanovesicles, respectively, by dialysis method. The action of UBC/OCA/anta-miR-34a loop on the regulation of lipid deposition via nanovesicles was evaluated on high-fat HepG2 cells and HFD-induced mice. The obtained dual drug-loaded nanovesicles UBC/OCA/anta-miR-34a could enhance the cellular uptake and intracellular release of OCA and anta-miR-34a, leading to the reduced lipid deposition in high-fat HepG2 cells. In NAFLD mice models, UBC/OCA/anta-miR-34a achieved the best curative effect on the recovery of body weight and hepatic function. Meanwhile, in vitro and vivo experiments validated that UBC/OCA/anta-miR-34a effectively activated the expression level of SIRT1 by enhancing the FXR/miR-34a/SIRT1 regulatory loop. This study provides a promising strategy for constructing oligochitosan-derivated nanovesicles to co-deliver OCA and anta-miR-34a for NAFLD treatment. STATEMENT OF SIGNIFICANCE: This study proposed a strategy to construct oligochitosan-derivated nanovesicles to co-deliver obeticholic acid and miR-34a antagomir for NAFLD treatment. Based on the FXR/miR-34a/SIRT1 action loop, this nanovesicle effectively exerted a synergetic effect of OCA and anta-miR-34a to significantly regulate lipid deposition and recover liver function in NAFLD mice.

Tumor suppressive functions of hsa­miR­34a on cell cycle, migration and protective autophagy in bladder cancer.

Bladder cancer (BC) cells exhibit a high basal level of autophagy activity, which contributes to the development of a protective mechanism for cellular survival against current treatments. Hsa­microRNA­34a (miR­34a) presents anti­tumor function in several types of cancer. However, the functional mechanism of miR­34a in regulating tumor aggressiveness and protective autophagy of BC remains largely unknown. First, transfected BC cells with miR­34a mimic exhibited LC3­II and p62 accumulation through immunofluorescence staining. It was demonstrated that syntaxin 17 (STX17), which is required for autophagosome­lysosome fusion, was downregulated upon miR­34a mimic treatment. Mechanistically, miR­34a reduced the expression of STX17 proteins that directly bind on STX17 3'­untranslated regions and thus suppressed STX17 mRNA translation to eventually inhibit protective autophagy in BC. Cell viability and colony formation assays revealed that overexpression of miR­34a in BC cells enhances the chemosensitivity of cisplatin, doxorubicin, epirubicin and mitomycin C. Furthermore, miR­34a inhibited cell proliferation and triggered G0/G1 cell cycle arrest by inhibiting cyclin D1 and cyclin E2 protein expression. Moreover, miR­34a suppressed cell motility through the downregulation of epithelial­mesenchymal transition. In summary, miR­34a inhibits cell proliferation, motility and autophagy activity in BC, which can benefit BC treatment.

Dexmedetomidine alleviates oxidative stress and mitochondrial dysfunction in diabetic peripheral neuropathy via the microRNA-34a/SIRT2/S1PR1 axis.

OBJECTIVE: Dexmedetomidine (Dex) is a highly selective α2-adrenoceptor agonist with sedative, analgesic, sympatholytic, and hemodynamic-stabilizing properties, which plays a neuroprotective role in diabetic peripheral neuropathy (DPN) and diabetes-induced nerve damage. However, the related molecular mechanisms are not fully understood. Therefore, our study explored the mechanism of Dex in DPN using rat and RSC96 cell models. METHODS: Sciatic nerve sections were observed under an optical microscope and the ultrastructure of the sciatic nerves was observed under a transmission electron microscope. Oxidative stress was assessed by detecting MDA, SOD, GSH-Px, and ROS levels. The motor nerve conduction velocity (MNCV), mechanical withdrawal threshold (MWT), and thermal withdrawal latency (TWL) of rats were measured. Cell viability, apoptosis, and the changes in the expression of related genes and proteins were examined. Furthermore, the relationship between microRNA (miR)-34a and SIRT2 or SIRT2 and S1PR1 was analyzed. RESULTS: Dex reversed DPN-induced decreases in MNCV, MWT, and TWL. Dex alleviated oxidative stress, mitochondrial damage, and apoptosis in both the rat and RSC96 cell models of DPN. Mechanistically, miR-34a negatively targeted SIRT2, and SIRT2 inhibited S1PR1 transcription. The overexpression of miR-34a or S1PR1 or the inhibition of SIRT2 counteracted the neuroprotective effects of Dex in DPN in vivo and in vitro. CONCLUSION: Dex alleviates oxidative stress and mitochondrial dysfunction associated with DPN by downregulating miR-34a to regulate the SIRT2/S1PR1 axis.

Metformin regulates chondrocyte senescence and proliferation through microRNA-34a/SIRT1 pathway in osteoarthritis.

BACKGROUND: Osteoarthritis (OA) is the most common degenerative disease in joints among elderly patients. Senescence is deeply involved in the pathogenesis of osteoarthritis. Metformin is widely used as the first-line drug for Type 2 diabetes mellitus (T2DM), and has great potential for the treatment of other aging-related disorders, including OA. However, the role of metformin in OA is not fully elucidated. Therefore, our aim here was to investigate the effects of metformin on human chondrocytes. METHODS: After metformin treatment, expression level of microRNA-34a and SIRT1 in chondrocyte were detected with quantitative real-time PCR and immunofluorescence staining. Then, microRNA-34a mimic and small interfering RNA (siRNA) against SIRT1 (siRNA-SIRT1) were transfected into chondrocyte. Senescence-associated ß-galactosidase (SA-ß-gal) staining was performed to assess chondrocyte senescence. Chondrocyte viability was illustrated with MTT and colony formation assays. Western blot was conducted to detect the expression of P16, IL-6, matrix metalloproteinase-13 (MMP-13), Collagen type II (COL2A1) and Aggrecan (ACAN). RESULTS: We found that metformin treatment (1 mM) inhibited microRNA-34a while promoted SIRT1 expression in OA chondrocytes. Both miR-34a mimics and siRNA against SIRT1 inhibited SIRT1 expression in chondrocytes. SA-ß-gal staining assay confirmed that metformin reduced SA-ß-gal-positive rate of chondrocytes, while transfection with miR-34a mimics or siRNA-SIRT1 reversed it. MTT assay and colony formation assay showed that metformin accelerated chondrocyte proliferation, while miR-34a mimics or siRNA-SIRT1 weakened this effect. Furthermore, results from western blot demonstrated that metformin suppressed expression of senescence-associated protein P16, proinflammatory cytokine IL-6 and catabolic gene MMP-13 while elevated expression of anabolic proteins such as Collagen type II and Aggrecan, which could be attenuated by transfection with miR-34a mimics. CONCLUSION: Overall, our data suggest that metformin regulates chondrocyte senescence and proliferation through microRNA-34a/SIRT1 pathway, indicating it could be a novel strategy for OA treatment.

NONHSAG028908.3 sponges miR­34a­5p to promote growth of colorectal cancer via targeting ALDOA.

Colorectal cancer (CRC) is an aggressive tumor, whose development is considered to be modulated by certain long non­coding RNAs (lncRNAs). Therefore, the aim of the present study was to investigate the regulatory mechanism of lncRNA NONHSAG028908.3 on CRC. Data from The Cancer Genome Atlas (TCGA) database revealed that NONHSAG028908.3 was increased in CRC tissues compared with normal tissues (P<0.001). The results of reverse transcription­quantitative PCR indicated that NONHSAG028908.3 was upregulated in four types of CRC cells compared with that in NCM460, a normal colorectal cell line. MTT, BrdU, and flow cytometric assays were applied to evaluate CRC cell growth. The migratory and invasive abilities of CRC cells were detected using wound healing and Transwell assays. Silencing of NONHSAG028908.3 inhibited proliferation, migration, and invasion of CRC cells. A dual­luciferase reporter assay demonstrated that NONHSAG028908.3 served as a sponge to combine with microRNA (miR)­34a­5p. MiR­34a­5p suppressed the aggressiveness of CRC cells. The effects induced by NONHSAG028908.3 knockdown were partly reversed by inhibition of miR­34a­5p. Furthermore, miR­34a­5p, a target of NONHSAG028908.3, modulated aldolase, fructose­bisphosphate A (ALDOA) expression in a negative feedback manner. Suppression of NONHSAG028908.3 notably decreased ALDOA expression, which was rescued via silencing of miR­34a­5p. Moreover, suppression of ALDOA revealed the inhibitory action on CRC cell growth and migration. In summary, the data of the present study indicate that NONHSAG028908.3 may positively regulate ALDOA via sponging miR­34a­5p, thereby promoting malignant activities in CRC.

Melatonin ameliorates arsenic-induced cardiotoxicity through the regulation of the Sirt1/Nrf2 pathway in rats.

Chronic arsenic (As) exposure, mainly as a result of drinking contaminated water, is associated with cardiovascular diseases. Mitochondrial dysfunction, oxidative stress, inflammation, apoptosis, and autophagy have been suggested as the molecular etiology of As cardiotoxicity. Melatonin (Mel) is a powerful antioxidant. Mel improves diabetic cardiomyopathy, cardiac remodeling, and heart failure. Following pre-treatment with Mel (10, 20, or 30 mg/kg/day i.p.), rats were orally gavaged with As (15 mg/kg/day) for 28 days. Electrocardiographic findings showed that Mel decreased the As-mediated QT interval prolongation. The effects of As on cardiac levels of glutathione (GSH) and malondialdehyde (MDA) were reversed by Mel pretreatment. Mel also modulated the Sirt1 and Nrf2 expressions promoted by As. Mel down-regulated autophagy markers such as Beclin-1 expression and the LC3-II/I ratio. Moreover, the cardiac expression of cleaved-caspase-3 and Bax/Bcl-2 ratio was decreased by Mel pretreatment. Reduced expression of miR-34a and miR-144 by As were reversed by Mel. The histopathological changes of cardiac injury associated with As exposure was moderated by Mel. Mel may improve As-induced cardiac dysfunction through anti-oxidative, anti-apoptotic, and anti-autophagic mechanisms.

The long-lasting effects of early life adversities are sex dependent: The signature of miR-34a.

BACKGROUND: Exposure to early life adversities (ELA) can influence a plethora of biological mechanisms leading to stress-related disorders later in life through epigenetic mechanisms, such as microRNAs (miRs). MiR-34 is a critical modulator of stress response and stress-induced pathologies and a link between ELA and miR-34a has been reported. METHODS: Here using our well-established model of ELA (Repeated Cross Fostering) we investigate the behavioral long-term effects of ELA in male and female mice. We also assess basal and ELA-induced miR-34a expression in adult mice and investigate whether ELA affects the later miR-34a response to adult acute stress exposure across brain areas (medial preFrontal Cortex, Dorsal Raphe Nuclei) and peripheral organs (heart, plasma) in animals from both sexes. Finally, based on our previous data demonstrating the critical role of Dorsal Raphe Nuclei miR-34a expression in serotonin (5-HT) transmission, we also investigated prefrontal-accumbal 5-HT outflow induced by acute stress exposure in ELA and Control females by in vivo intracerebral microdialysis. RESULTS: ELA not just induces a depressive-like state as well as enduring changes in miR-34a expression, but also alters miR-34a expression in response to adult acute stress exclusively in females. Finally, altered DRN miR-34a expression is associated with prefrontal-accumbal 5-HT release under acute stress exposure in females. LIMITATIONS: Translational study on humans is necessary to verify the results obtained in our animal models of ELA-induced depression. CONCLUSIONS: This is the first evidence showing long-lasting sex related effects of ELA on brain and peripheral miR-34a expression levels in an animal model of depression-like phenotype.

Involvement of miRNA-34a regulated Krüppel-like factor 4 expression in hyperoxia-induced senescence in lung epithelial cells.

BACKGROUND: Premature infants, subjected to supplemental oxygen and mechanical ventilation, may develop bronchopulmonary dysplasia, a chronic lung disease characterized by alveolar dysplasia and impaired vascularization. We and others have shown that hyperoxia causes senescence in cultured lung epithelial cells and fibroblasts. Although miR-34a modulates senescence, it is unclear whether it contributes to hyperoxia-induced senescence. We hypothesized that hyperoxia increases miR-34a levels, leading to cellular senescence. METHODS: We exposed mouse lung epithelial (MLE-12) cells and primary human small airway epithelial cells to hyperoxia (95% O2/5% CO2) or air (21% O2/5% CO2) for 24 h. Newborn mice (< 12 h old) were exposed to hyperoxia (> 95% O2) for 3 days and allowed to recover in room air until postnatal day 7. Lung samples from premature human infants requiring mechanical ventilation and control subjects who were not mechanically ventilated were employed. RESULTS: Hyperoxia caused senescence as indicated by loss of nuclear lamin B1, increased p21 gene expression, and senescence-associated secretory phenotype factors. Expression of miR-34a-5p was increased in epithelial cells and newborn mice exposed to hyperoxia, and in premature infants requiring mechanical ventilation. Transfection with a miR-34a-5p inhibitor reduced hyperoxia-induced senescence in MLE-12 cells. Additionally, hyperoxia increased protein levels of the oncogene and tumor-suppressor Krüppel-like factor 4 (KLF4), which were inhibited by a miR-34a-5p inhibitor. Furthermore, KLF4 knockdown by siRNA transfection reduced hyperoxia-induced senescence. CONCLUSION: Hyperoxia increases miR-34a-5p, leading to senescence in lung epithelial cells. This is dictated in part by upregulation of KLF4 signaling. Therefore, inhibiting hyperoxia-induced senescence via miR-34a-5p or KLF4 suppression may provide a novel therapeutic strategy to mitigate the detrimental consequences of hyperoxia in the neonatal lung.

Molecular Characteristics of Bladder Tumor: Increased Gene Expression of MAGE-A6 and MAGE-A11 with Decreased MicroRNA-34a and MicroRNA-125b.

Bladder cancer is recognized as one of the top ten most common cancers worldwide. Activation of oncogenes, inactivation of tumor suppressor genes, and dysregulation of androgen signaling pathways are three major pathophysiological causes in the development of bladder tumors. Discovering potential biomarkers is required for the management and immunotherapy of bladder cancer. Melanoma-associated antigen (MAGE)-A6 and MAGE-A11 are two cancer-testis antigens that are potential coregulators of androgen receptors. MicroRNAs, especially miR-34a and miR-125b are two important tumor suppressors that play a critical role in regulating different signaling pathways and inhibiting tumor development. Twenty-nine surgical tissue biopsies were collected from patients with no preoperative chemotherapy or radiotherapy (26 males and, 3 females, mean age±SD: 62.4±13.3 years). Seventeen adjacent uninvolved tissues with no abnormalities upon histological examination were considered normal controls (14 males and, 3 females, mean age±SD: 64.2±7.4 years) . Quantitative PCR was performed to evaluate the gene expression level of MAGE-A6, MAGE-A11, miR-34a, and miR-125b in bladder cancer biopsies. MAGE-A6 and MAGE-A11 expressions were significantly increased in bladder tumors compared with normal tissues. However, the expression levels of miR-34a and miR-125b were significantly downregulated in bladder tumor tissues. Interestingly, the expression level of all these genes was significantly associated with tumor grade, pathological stage (pT), and muscular invasion. MAGE-A6 and MAGE-A11 can be considered potential markers for the diagnosis and immunotherapy of bladder tumors. Furthermore, the modulation of miR-34a and miR-125b gene expression in association with increased MAGE-A6 and MAGE-A11 genes could open a new horizon in the improvement of bladder cancer.

Tanshinone IIA improves diabetes-induced renal fibrosis by regulating the miR-34-5p/Notch1 axis.

The purpose of this study was to evaluate the improvement of tanshinone in renal fibrosis in vitro and in vivo study. It used streptozotocin to model diabetic nephropathy (DN) mice, and treated with different Tanshinone IIA concentrations. The pathology of kidney tissues was evaluated by hematoxylin and eosin (H&E) and Masson's staining; the ultrastructure and apoptosis cell number of kidney tissues were evaluated by transmission electron microscopy (TEM) and TUNEL assay. Relative gene and protein expression was evaluated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), immunohistochemical (IHC) analysis, or western blot (WB) assay. In vitro study, using high-glucose stimulated HK-2 cell to model DN cell model, measuring cell proliferation, apoptosis rate, relative gene and protein expression, and LC 3B and P62 proteins expression by Cell Counting Kit-8 (CCK-8), flow cytometry, RT-qPCR, WB, and cell immunofluorescence. Analysis correlation between Notch1 and miRNA-34a-5p was carried out by dual-luciferase reporter. Fibrosis area and apoptosis cell rate were significantly up-regulated (p < .001), with Tanshinone IIA supplement. The fibrosis area and apoptosis cell rate were also significantly improved in a dose-dependent manner (p < .05). With si-miRNA-34a-5p transfection, the Tanshinone IIA's treatment effects were significantly depressed. By dual-luciferase reporter, miRNA-34a-5p could target Notch1 in the HK-2 cell line. Tanshinone IIA improved DN-induced renal fibrosis by regulating miRNA-34a-5p in vitro and in vivo study.

MicroRNA-34a, Prostate Cancer Stem Cells, and Therapeutic Development.

Prostate cancer (PCa) is a highly heterogeneous disease and typically presents with multiple distinct cancer foci. Heterogeneity in androgen receptor (AR) expression levels in PCa has been observed for decades, from untreated tumors to castration-resistant prostate cancer (CRPC) to disseminated metastases. Current standard-of-care therapies for metastatic CRPC can only extend life by a few months. Cancer stem cells (CSCs) are defined as a subpopulation of cancer cells that exists in almost all treatment-naive tumors. Additionally, non-CSCs may undergo cellular plasticity to be reprogrammed to prostate cancer stem cells (PCSCs) during spontaneous tumor progression or upon therapeutic treatments. Consequently, PCSCs may become the predominant population in treatment-resistant tumors, and the "root cause" for drug resistance. microRNA-34a (miR-34a) is a bona fide tumor-suppressive miRNA, and its expression is dysregulated in PCa. Importantly, miR-34a functions as a potent CSC suppressor by targeting many molecules essential for CSC survival and functions, which makes it a promising anti-PCSC therapeutic. Here, we conducted a comprehensive literature survey of miR-34a in the context of PCa and especially PCSCs. We provided an updated overview on the mechanisms of miR-34a regulation followed by discussing its tumor suppressive functions in PCa. Finally, based on current advances in miR-34a preclinical studies in PCa, we offered potential delivery strategies for miR-34a-based therapeutics for treating advanced PCa.

MicroRNA-34a: A Novel Therapeutic Target in Fibrosis.

Fibrosis can occur in many organs, and severe cases leading to organ failure and death. No specific treatment for fibrosis so far. In recent years, microRNA-34a (miR-34a) has been found to play a role in fibrotic diseases. MiR-34a is involved in the apoptosis, autophagy and cellular senescence, also regulates TGF-ß1/Smad signal pathway, and negatively regulates the expression of multiple target genes to affect the deposition of extracellular matrix and regulate the process of fibrosis. Some studies have explored the efficacy of miR-34a-targeted therapies for fibrotic diseases. Therefore, miR-34a has specific potential for the treatment of fibrosis. This article reviews the important roles of miR-34a in fibrosis and provides the possibility for miR-34a as a novel therapeutic target in fibrosis.

MicroRNA-34a and microRNA-146a target CELF3 and suppress the osteogenic differentiation of periodontal ligament stem cells under cyclic mechanical stretch.

Background/purpose: During orthodontic tooth movement, mechanical forces induce the osteogenic differentiation of periodontal ligament stem cells (PDLSCs), which contributes to alveolar bone remodeling. MicroRNAs (miRNAs) are involved in regulating PDLSC osteogenic differentiation. Therefore, we intended to explore the role of miR-34a and miR-146a in osteogenic differentiation of PDLSCs under cyclic stretch. Materials and methods: Phenotypic identification of PDLSCs was determined by flow cytometry analysis. PDLSCs were incubated with osteogenic differentiation medium for 3 weeks and the osteogenic differentiation capability was detected by Alizarin Red staining. To mimic the orthodontic forces, cyclic mechanical stretch was applied to PDLSCs. Alkaline phosphatase (ALP) activity assay and ALP staining were used for evaluating the ALP activity. The expression of osteogenesis markers in PDLSCs was assessed by western blotting and qRT-PCR. The binding between miR-34a (or miR-146a) and CUGBP Elav-like family member 3 (CELF3) was validated by luciferase reporter assay. Results: Cyclic stretch elevated ALP activity and the expression of osteogenesis markers, osteopontin (OPN), runt-related transcription factor 2 (RUNX2), type I collagen (COL1), ALP, osteocalcin (OCN) and osterix (OSX), in PDLSCs. MiR-146a and miR-34a were downregulated in PDLSCs under cyclic stretch. Either overexpressing miR-146a and miR-34a reduced ALP activity and the expression of osteogenesis markers. CELF3 was a target of both miR-146a and miR-34a. CELF3 silencing attenuated while CELF3 overexpression enhanced ALP activity and the expression of osteogenesis markers. Conclusion: MiR-34a and miR-146a repress cyclic stretch-induced osteogenic differentiation of PDLSCs via regulating the expression of CELF3.

In vitro experimental study on the formation of microRNA-34a loaded exosomes and their inhibitory effect in oral squamous cell carcinoma.

Studies have shown the inhibitory effect of microRNA-34a on proliferation, migration, and invasion of oral squamous cell carcinoma. However, the lack of a safe and effective delivery system limits the clinical application of microRNA-34a in oral cancer treatment. An exosome is a small extracellular vesicle that mediates intercellular communication by delivering proteins, nucleic acids, and other contents, and functions as a natural drug delivery carrier. Here, we aimed to explore whether exosomes could be used to load microRNA-34a via co-incubation and further used to treat OSCC. Ultracentrifugation was used to obtain exosomes derived from HEK293T cells and the extracted exosomes were analyzed via transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Western blotting. Subsequently, we loaded cholesterol-modified microRNA-34a into HEK293T cell exosomes by co-incubation. Then, PKH67 and Cy3 co-labeled exo-microRNA-34a were co-incubated with HN6 cells and exosome entry into the HN6 cells was observed using a confocal laser scanning microscope. The cell proliferation, migration, and invasion were assessed by CCK-8 and Transwell assay analysis. SATB2 expression in HN6 cells was analyzed via western blotting. In this study, cholesterol-modified microRNA-34a was loaded into exosomes of HEK293T cells by co-incubation. The microRNA-34a-loaded exosomes were secreted from HEK293T cells and were absorbed by HN6 oral squamous carcinoma cells. Further, microRNA-34a-loaded exosomes led to a significant inhibition of HN6 cell proliferation, migration, and invasion by down regulating SATB2 expression. These results report a new delivery method for microRNA-34a, providing a new approach for the treatment of oral cancer.

MicroRNA-34a-5p as a promising early circulating preclinical biomarker of doxorubicin-induced chronic cardiotoxicity.

Cardiotoxicity is a serious adverse effect of an anticancer drug, doxorubicin (DOX), which can occur within a year or decades after completion of therapy. The present study was designed to address a knowledge gap concerning a lack of circulating biomarkers capable of predicting the risk of cardiotoxicity induced by DOX. Profiling of 2083 microRNAs (miRNAs) in mouse plasma revealed 81 differentially expressed miRNAs 1 week after 6, 9, 12, 18, or 24 mg/kg total cumulative DOX doses (early-onset model) or saline (SAL). Among these, the expression of seven miRNAs was altered prior to the onset of myocardial injury at 12 mg/kg and higher cumulative doses. The expression of only miR-34a-5p was significantly (false discovery rate [FDR] < 0.1) elevated at all total cumulative doses compared with concurrent SAL-treated controls and showed a statistically significant dose-related response. The trend in plasma miR-34a-5p expression levels during DOX exposures also correlated with a significant dose-related increase in cardiac expression of miR-34a-5p in these mice. Administration of a cardioprotective drug, dexrazoxane, to mice before DOX treatment, significantly mitigated miR-34a-5p expression in both plasma and heart in conjunction with attenuation of cardiac pathology. This association between plasma and heart may suggest miR-34a-5p as a potential early circulating marker of early-onset DOX cardiotoxicity. In addition, higher expression of miR-34a-5p (FDR < 0.1) in plasma and heart compared with SAL-treated controls 24 weeks after 24 mg/kg total cumulative DOX dose, when cardiac function was altered in our recently established delayed-onset cardiotoxicity model, indicated its potential as an early biomarker of delayed-onset cardiotoxicity.

MicroRNA-34a in coronary heart disease: Correlation with disease risk, blood lipid, stenosis degree, inflammatory cytokines, and cell adhesion molecules.

BACKGROUND: MicroRNA-34a (miR-34a) plays an essential role in regulating blood lipid, inflammation, cell adhesion molecules, and atherosclerosis, the latter factors are closely involved in the etiology of coronary heart disease (CHD). However, the clinical value of miR-34a in CHD patients' management is rarely reported. Hence, this study aimed to assess the correlation of miR-34a with disease risk, blood lipid, coronary artery stenosis, inflammatory cytokines, and cell adhesion molecules of CHD. METHODS: A total of 203 CHD patients and 100 controls were recruited in this study, then their plasma samples were collected to detect the miR-34a by reverse transcription quantitative polymerase chain reaction. Furthermore, serum samples from CHD patients were obtained for inflammatory cytokines and cell adhesion molecule measurement by enzyme-linked immunosorbent assay. RESULTS: MiR-34a was elevated in CHD patients compared to controls (p < 0.001) and it disclosed a good diagnostic value of CHD (area under curve: 0.899, 95% confidence interval: 0.865-0.934). Besides, miR-34a positively correlated with triglyceride (p < 0.001), total cholesterol (p = 0.022) and low-density lipoprotein cholesterol (p = 0.004), but not with high-density lipoprotein cholesterol (p = 0.110) in CHD patients. Moreover, miR-34a associated with Gensini score in CHD patients (p < 0.001). As to inflammation-related indexes and cell adhesion molecules, MiR-34a expression was positively linked with C-reactive protein (p < 0.001), tumor necrosis factor alpha (p = 0.005), interleukin (IL)-1ß (p = 0.020), IL-17A (p < 0.001), vascular cell adhesion molecule-1 (p < 0.001), and intercellular adhesion molecule-1 (p = 0.010) in CHD patients, but not with IL-6 (p = 0.118) and IL-10 (p = 0.054). CONCLUSION: MiR-34a might serve as a biomarker in assistance of diagnosis and management of CHD.