The Association of pri-miR34 b/c Gene Polymorphism and Clinicopathologic Data in Breast Cancer Patients.

BACKGROUND: MiR-34b/c takes an important role in various aspects of carcinogenesis. Notably, pri miR34b/c (rs4938723) T>C polymorphism has been identified as a significant biomarker in various kinds of cancer. The objective of this study was to explore whether pri-miR34b/c rs4938723) T>C was associated with breast cancer susceptibility. Moreover, the association of pri-miR34b/c (rs4938723) T>C and clinicopathologic data, including survival outcomes, were studied in Thai breast cancer patients. METHODS: DNA extracted from the blood of 100 Thai female breast cancer patients and 100 Thai healthy women were investigated for pri-miR34b/c (rs4938723) T>C polymorphism using polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP). RESULTS: There was no statistically significant difference between the frequency of pri miR34b/c (rs4938723) T>C genotype between Thai breast cancer patients and normal subjects. This study showed that there is no association between pri-miR34b/c (rs4938723) genotypes and breast cancer susceptibility, clinicopathologic parameters, and survival time. However, age greater than 50 and histologic grade III were the prognostic factors affecting survival in breast cancer patients (p=0.017, p=0.010, respectively). CONCLUSION: The pri-miR34b/c (rs4938723) genotypes had no association with cancer susceptibility and clinicopathologic parameters in Thai breast cancer patients. Patients with older age and patients with higher histologic grade, but not the pri miR34b/c (rs4938723) genotype, affected survival time among breast cancer patients.

miR-34b-5p suppresses the epithelial-mesenchymal transition and metastasis in endometrial cancer AN3CA cells by targeting ZEB1.

OBJECTIVES: Tumor metastasis is a primary cause of recurrence and mortality in endometrial cancer. miR-34b-5p is abnormally expressed in various cancers and participates in tumor cell progression and metastasis. The objective of this study was to elucidate the biological functions and molecular mechanisms of miR-34b-5p in regulating the epithelial-mesenchymal transition (EMT) and metastasis in AN3CA endometrial cancer cells. METHODS: The expression levels of miR-34b-5p and zinc finger E-box-binding homeobox 1 (ZEB1) in endometrial cancer cells were analyzed by qRT-PCR, and ZEB1 expression in endometrial cancer tissues was examined by immunohistochemistry. Proliferation, migration, and invasion of endometrial cancer AN3CA cells were evaluated using CCK8, scratch, and transwell assays, respectively. Bioinformatic analysis and dual-luciferase reporter gene assays were used to validate the targeting relationship between miR-34b-5p and ZEB1. Western blotting was performed to analyze the expression levels of ZEB1 and EMT-related proteins. RESULTS: miR-34b-5p was significantly downregulated in endometrial cancer AN3CA cells. Overexpression of miR-34b-5p significantly inhibited proliferation, invasion, migration, and the EMT of endometrial cancer AN3CA cells. ZEB1, which was identified as a direct target gene of miR-34b-5p, exhibited high expression in endometrial cancer cells and tissues. Additionally, ZEB1 upregulation partially reversed the inhibitory effects of miR-34b-5p on proliferation, migration, invasion, and the EMT of endometrial cancer AN3CA cells. CONCLUSIONS: miR-34b-5p suppresses the EMT and metastasis in endometrial cancer AN3CA cells by targeting ZEB1, indicating that the miR-34b-5p-ZEB1-EMT axis may be a therapeutic target for endometrial cancer.

FOXO3 suppresses lymphoma progression through promoting miR-34b/HSPG2 axis.

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoma, which caused many patients to lose their precious lives. FOXO3 was a suppressor in various cancers, however, the role and mechanism of FOXO3 in DLBCL remain unclear. METHODS: Bioinformatics analysis was used to offer information FOXO3 expression and its expression for prognosis of DLBCL patients. The abundance of genes and proteins was evaluated using RT-qPCR and western blot. Cell proliferation and apoptosis was detected by CCK-8 and flow cytometry. The interactions among FOXO3, miR-34b, and HSPG2 were predicted by TransmiR and Starbase and validated using dual luciferase reporter assay, ChIP assay, and RIP assay. RESULTS: Our findings revealed that FOXO3 expression was abnormally declined in DLBCL cells. FOXO3 upregulation restrained cell proliferation and promoted cell apoptosis of DLBCL cells, while miR-34b inhibitor eliminated these influences. Similarly, miR-34b mimic suppressed malignant behaviors of DLBCL cells, which were abolished by HSPG2 overexpression. Mechanically, FOXO3 induced miR-34b expression through interacting with miR-34b promoter and HSPG2 was a targeted gene of miR-34b. CONCLUSION: FOXO3 attenuated the capability of cell proliferation and promoted cell apoptosis rate of DLBCL cells through affecting miR-34b/HSPG2 axis, therefore inhibiting DLBCL progression.

Circ_0001786 facilitates gefitinib resistance and malignant progression in non-small cell lung cancer via miR-34b-5p/SRSF1.

BACKGROUND: Non-small cell lung cancer (NSCLC) is a widespread cancer and gefitinib is a primary therapy for NSCLC patients. Nevertheless, the underlying mechanisms for the progression of acquired drug resistance have not been clarified. The aim of this study was to investigate the role of circular RNA (circ_0001786) in gefitinib-resistant NSCLC. METHODS: Firstly, the expression of circ_0001786, miR-34b-5p and SRSF1 were assayed using qRT-PCR. Subsequently, CCK-8 test was utilized to measure the semi-inhibitory concentration (IC50) of cellular gefitinib. Apoptosis was identified by flow cytometry. At last, dual luciferase assay was applied to prove the binding association between miR-34b-5p, circ_0001786 or SRSF1. RESULTS: Our research disclosed that circ_0001786 was heightened in gefitinib-resistant NSCLC cells and tissues. Knockdown of circ_0001786 restrained IC50 values of gefitinib, attenuated the clonogenic ability and facilitated apoptosis in HCC827-GR and PC9-GR. In addition, circ_0001786 was a molecular sponge for miR-34b-5p. Silencing miR-34b-5p rescued the inhibitory impact of circ_0001786 knockdown on IC50 and cell cloning ability. Moreover, miR-34b-5p directly targeted SRSF1. Importantly, circ_0001786 enhanced gefitinib tolerance and malignant development in NSCLC through miR-34b-5p/SRSF1 pathway. CONCLUSION: This research revealed a novel mechanism by which circ_0001786 enhanced NSCLC resistance to gefitinib by sponging miR-34b-5p and upregulating SRSF1. circ_0001786 was a potential target for improving the treatment of gefitinib-resistant NSCLC patients.

miR-34b-3p-mediated regulation of STC2 and FN1 enhances chemosensitivity and inhibits proliferation in cervical cancer.

Dysregulation of microRNA (miRNA) expression in cancer is a significant factor contributing to the progression of chemoresistance. The objective of this study is to explore the underlying mechanisms by which miR-34b-3p regulates chemoresistance in cervical cancer (CC). Previous findings have demonstrated low expression levels of miR-34b-3p in both CC chemoresistant cells and tissues. In this study, we initially characterize the behavior of SiHa/DDP cells which are CC cells resistant to the chemotherapeutic drug cisplatin (DDP). Subsequently, miR-34b-3p mimics are transfected into SiHa/DDP cells. It is observed that overexpression of miR-34b-3p substantially inhibits the proliferation, migration, and invasion abilities of SiHa/DDP cells and also enhances their sensitivity to DDP-induced cell death. Quantitative RT-PCR and western blot analysis further reveal elevated expression levels of STC2 and FN1 in SiHa/DDP cells, contrary to the expression pattern of miR-34b-3p. Moreover, STC2 and FN1 contribute to DDP resistance, proliferation, migration, invasion, and decreased apoptosis in CC cells. Through dual-luciferase assay analysis, we confirm that STC2 and FN1 are direct targets of miR-34b-3p in CC. Finally, rescue experiments demonstrate that overexpression of either STC2 or FN1 can partially reverse the inhibitory effects of miR-34b-3p overexpression on chemoresistance, proliferation, migration and invasion in CC cells. In conclusion, our findings support the role of miR-34b-3p as a tumor suppressor in CC. This study indicates that targeting the miR-34b-3p/STC2 or FN1 axis has potential therapeutic implications for overcoming chemoresistance in CC patients.

Functional pri-miR-34b/c rs4938723 and KRAS 3'UTR rs61764370 SNPs: Novel phenotype modifiers in Li-Fraumeni Syndrome?

PURPOSE: Li-Fraumeni Syndrome (LFS) is a rare cancer predisposing condition caused by germline pathogenic TP53 variants, in which core tumors comprise sarcomas, breast, brain and adrenocortical neoplasms. Clinical manifestations are highly variable in carriers of the Brazilian germline founder variant TP53 p.R337H, possibly due to the influence of modifier genes such as miRNA genes involved in the regulation of the p53 pathway. Herein, we investigated the potential phenotypic effects of two miRNA-related functional SNPs, pri-miR-34b/c rs4938723 and 3'UTR KRAS rs61764370, in a cohort of 273 LFS patients from Southern and Southeastern Brazil. METHODS: The genotyping of selected SNPs was performed by TaqMan® allelic discrimination and subsequently custom TaqMan® genotyping results were confirmed by Sanger sequencing in all SNP-positive LFS patients. RESULTS: Although the KRAS SNP showed no effect as a phenotype modulator, the rs4938723 CC genotype was significantly associated with development of LFS non-core tumors (first tumor diagnosis) in p.R337H carriers (p = 0.039). Non-core tumors were also more frequently diagnosed in carriers of germline TP53 DNA binding domain variants harboring the rs4938723 C variant allele. Previous studies described pri-miR-34b/c rs4938723 C as a risk allele for sporadic occurrence of thyroid and prostate cancers (non-core tumors of the LFS spectrum). CONCLUSION: With this study, we presented additional evidence about the importance of analyzing miRNA genes that could indirectly regulate p53 expression, and, therefore, may modulate the LFS phenotype, such as those of the miR-34 family.

The miR-34b/MEK/ERK pathway is regulated by NR5A1 and promotes differentiation in primary bovine Sertoli cells.

Sertoli cells play a key role in testicular development and spermatogenesis. It has been suggested that Sertoli cells differentiate after their proliferation ceases. Our previous study showed that miR-34b inhibits proliferation by targeting MAP2K1 mediated MEK/ERK signaling pathway in bovine immature Sertoli cells. Subsequent studies have revealed that the differentiation marker androgen receptor is upregulated during this process. However, the effect of the miR-34b/MEK/ERK pathway on immature bovine Sertoli cell differentiation and the underlying molecular mechanisms are yet to be explored. In this study, we determined that the miR-34b/MEK/ERK pathway was involved in the differentiation of primary Sertoli cells (PSCs) in response to retinoic acid. Transfection of an miR-34b mimic into PSCs promoted cell differentiation, whereas transfection of an miR-34b inhibitor into PSCs delayed it. Pharmacological inhibition of MEK/ERK signaling by AZD6244 promoted PSCs differentiation. Mechanistically, miR-34b promoted PSCs differentiation by inhibiting the MEK/ERK signaling pathway. Through a combination of bioinformatics analysis, dual-luciferase reporter assay, quantitative real-time PCR, and western blotting, nuclear receptor subfamily 5 group A member 1 (NR5A1) was identified as an upstream negative transcription factor of miR-34b. Furthermore, NR5A1 knockdown promoted Sertoli cell differentiation, whereas NR5A1 overexpression had the opposite effect. Together, this study revealed a new NR5A1/miR-34b/MEK/ERK axis that plays a significant role in Sertoli cell differentiation and provides a theoretical and experimental framework for further clarifying the regulation of cell differentiation in bovine PSCs.

Sirtuin1 inhibits calcium oxalate crystal-induced kidney injury by regulating TLR4 signaling and macrophage-mediated inflammatory activation.

Sirtuin1 (Sirt1) activation significantly attenuated calcium oxalate (CaOx) crystal deposition and renal inflammatory injury by regulating renal immune microenvironment. Here, to elucidate the molecular mechanism underlying the therapeutic effects of Sirt1 on macrophage related inflammation and tubular epithelial cells (TECs) necrosis, we constructed a macrophage and CaOx monohydrate (COM)-stimulated tubular cell co-culture system to mimic immune microenvironment in kidney and established a mouse model of CaOx nephrocalcinosis in wild-type and myeloid-specific Sirt1 knockout mice. Target prediction analyses of Gene Expression Omnibus Datasets showed that only miR-34b-5p is regulated by lipopolysaccharides and upregulated by SRT1720 and targets the TLR4 3'-untranslated region. In vitro, SRT1720 suppressed TLR4 expression and M1 macrophage polarization and decreased reactive oxygen species (ROS) production and mitochondrial damage in COM-stimulated TECs by targeting miR-34b-5p. Mechanically, Sirt1 promoted miR-34b-5p expression by suppressing the tri-methylation of H3K27, which directly bound to the miR-34b-5p promoter and abolished the miR-34b-5p transcription. Furthermore, loss of Sirt1 aggravated CaOx nephrocalcinosis-induced inflammatory and oxidative kidney injury, while AgomiR-34b reversed these effects. Therefore, our data suggested that Sirt1 inhibited TLR4 signaling and M1 macrophage polarization and decreased inflammatory and oxidative injury of TECs in vitro and in vivo.

Association of TP53 rs1042522 G > C, MDM2 rs2279744 T > G, and miR-34b/c rs4938723 T > C polymorphisms with aneuploidy pregnancy susceptibility.

BACKGROUND: Aneuploidy pregnancy is a severe major birth defect and causes about 50% spontaneous miscarriages with unknown etiology. To date, only a few epidemiological studies with small sample sizes have investigated the risk factors for aneuploidy pregnancy. TP53, MDM2, and miR-34b/c genes are implicated in tumorigenesis with aneuploidy, yet the function of their polymorphisms in aneuploidy pregnancy susceptibility needs to be clarified. OBJECTIVE: To elucidate the association of TP53 rs1042522 G > C, MDM2 rs2279744 309 T > G, and miR-34b/c rs4938723 T > C specific polymorphisms with aneuploidy pregnancy. METHODS: In the retrospective case-control study, 330 aneuploidies pregnancy women and 813 normal pregnancy controls were recruited between January 2018 and April 2022 at the First People's Hospital of Yunnan Province, Kunming, China. Three functional polymorphisms, the TP53 rs1042522 G > C (Arg72Pro), MDM2 rs2279744 309 T > G, and miR-34b/c rs4938723 T > C, were genotyped using the snapshot method. RESULTS: The frequency distribution of three genotypic variants was not different between case and control pregnant women and was similar to with Hardy-Weinberg Equilibrium (HWE). However, in the younger subgroup (less than 35 years old), a significant difference was detected in allele and recessive model (p = 0.01). In the advanced age subgroup (more than or equal to 35 years old), G of MDM2 rs2279744 T > G revealed a significantly higher frequency in cases than controls (p = 0.045), and miR-34b/c rs4938723 T > C revealed a significant difference under the dominant model (p = 0.03), but no significant differences were observed in other models and in both younger and older subgroup (p > 0.05, respectively). These results suggest that individual polymorphisms were not associated with aneuploidy pregnancy, combined with age, they may serve as a risk factor for aneuploidy pregnancy. CONCLUSION: Combination of TP53 rs1042522 G > C, MDM2 rs2279744 T > G, and miR-34b/c rs4938723 T > C polymorphisms with maternal age may be related to aneuploidy pregnancy susceptibility. These findings might elaborate on the genetic etiology of aneuploidy pregnancy.

Host microRNA interactions with the SARS-CoV-2 viral genome 3'-untranslated region.

The 2019 pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has marked the spread of a novel human coronavirus. While the viral life cycle is well understood, most of the interactions at the virus-host interface remain elusive. Furthermore, the molecular mechanisms behind disease severity and immune evasion are still largely unknown. Conserved elements of the viral genome such as secondary structures within the 5'- and 3'-untranslated regions (UTRs) serve as attractive targets of interest and could prove crucial in furthering our understanding of virus-host interactions. It has been proposed that microRNA (miR) interactions with viral components could be used by both the virus and host for their own benefit. Analysis of the SARS-CoV-2 viral genome 3'-UTR has revealed the potential for host cellular miR binding sites, providing sites for specific interactions with the virus. In this study, we demonstrate that the SARS-CoV-2 genome 3'-UTR binds the host cellular miRNAs miR-760-3p, miR-34a-5p, and miR-34b-5p, which have been shown to influence translation of interleukin-6 (IL-6), the IL-6 receptor (IL-6R), as well as progranulin (PGRN), respectively, proteins that have roles in the host immune response and inflammatory pathways. Furthermore, recent work suggests the potential of miR-34a-5p and miR-34b-5p to target and inhibit translation of viral proteins. Native gel electrophoresis and steady-state fluorescence spectroscopy were utilized to characterize the binding of these miRs to their predicted sites within the SARS-CoV-2 genome 3'-UTR. Additionally, we investigated 2'-fluoro-D-arabinonucleic acid (FANA) analogs of these miRNAs as competitive binding inhibitors for these miR binding interactions. The mechanisms detailed in this study have the potential to drive the development of antiviral treatments for SARS-CoV-2 infection, and provide a potential molecular basis for cytokine release syndrome and immune evasion which could implicate the host-virus interface.

The miR-34b-5p-negative target Gnai2 aggravates fluorine combined with aluminum-induced apoptosis of rat offspring hippocampal neurons and NG108-15 cells.

It is known that fluorine and aluminum are commonly found in the environment and that long-term overexposure can adversely affect the organism's nervous system, damaging the structure and function of brain tissue. Our previous study showed that fluorine combined with aluminum (FA) could trigger apoptosis in vitro and cause spatial learning and memory impairment and differentially expressed miRNAs (including miR-34b-5p) in the hippocampi in vivo. However, the detailed mechanism is unclear. Learning memory damage is implicated in excessive hippocampal neuron apoptosis, and miR-34b-5p participates in regulating the hippocampal neuron apoptosis. Thus, in the current research, Sprague-Dawley (SD) rats were subjected to FA, and NG108-15 control cells and NG108-15 cells pretransfected with miR-34b-5p agomir or antagomir were exposed to FA. We found that FA triggered apoptosis of rat hippocampal neurons and NG108-15 cells, increased miR-34b-5p expression, and decreased Gnai2, PKA, ERK and CREB expression. Inhibition of miR-34b-5p alleviated FA-induced NG108-15 cell apoptosis and further increased Gnai2, PKA, ERK, and CREB expression, and vice versa. Furthermore, miR-34b-5p modulated the level of Gnai2 by directly targeting its 3'-untranslated region (UTR), as verified through the dual Luciferase reporter assay. These outcomes suggested that miR-34b-5p participated in FA-induced neuronal apoptosis by targeting Gnai2 negatively, thereby inhibiting the PKA/ERK/CREB signaling pathway.

The MIR34B/C genomic region contains multiple potential regulators of multiciliogenesis.

The MIR449 genomic locus encompasses several regulators of multiciliated cell (MCC) formation (multiciliogenesis). The miR-449 homologs miR-34b/c represent additional regulators of multiciliogenesis that are transcribed from another locus. Here, we characterized the expression of BTG4, LAYN, and HOATZ, located in the MIR34B/C locus using single-cell RNA-seq and super-resolution microscopy from human, mouse, or pig multiciliogenesis models. BTG4, LAYN, and HOATZ transcripts were expressed in both precursors and mature MCCs. The Layilin/LAYN protein was absent from primary cilia, but it was expressed in apical membrane regions or throughout motile cilia. LAYN silencing altered apical actin cap formation and multiciliogenesis. HOATZ protein was detected in primary cilia or throughout motile cilia. Altogether, our data suggest that the MIR34B/C locus may gather potential actors of multiciliogenesis.

IDH2 Deficiency Promotes Endothelial Senescence by Eliciting miR-34b/c-Mediated Suppression of Mitophagy and Increased ROS Production.

Endothelial senescence impairs vascular function and thus is a primary event of age-related vasculature diseases. Isocitrate dehydrogenase 2 (IDH2) plays an important role in inducing alpha-ketoglutarate (α-KG) production and preserving mitochondrial function. However, the mechanism and regulation of IDH2 in endothelial senescence have not been elucidated. We demonstrated that downregulation of IDH2 induced accumulation of miR-34b/c, which impaired mitophagy and elevated mitochondrial reactive oxygen species (ROS) levels by inhibiting mitophagy-related markers (PTEN-induced putative kinase 1 (PINK1), Parkin, LC-II/LC3-I, and p62) and attenuating Sirtuin deacetylation 3 (Sirt3) expression. The mitochondrial dysfunction induced by IDH2 deficiency disrupted cell homeostasis and the cell cycle and led to endothelial senescence. However, miR-34b/c inhibition or α-KG supplementation restored Sirt3, PINK1, Parkin, LC-II/LC3-I, p62, and mitochondrial ROS levels, subsequently alleviating endothelial senescence. We showed that IDH2 played a crucial role in regulating endothelial senescence via induction of miR-34b/c in endothelial cells.

miR-34b/c-5p/CXCL10 Axis Induced by RSV Infection Mediates a Mechanism of Airway Hyperresponsive Diseases.

Background: RSV is closely correlated with post-infection airway hyperresponsive diseases (AHD), but the mechanism remains unclear. Objective: Due to the pivotal role of miRNAs in AHD, we analyzed the differentially expressed miRNAs (DEmiRs) in RSV-infected patients, asthma patients, and COPD patients from public datasets and explored the mechanisms of association between RSV and AHD. Methods: We obtained miRNA and mRNA databases of patients with RSV infection, as well as miRNA databases of asthma and COPD patients from the GEO database. Through integrated analysis, we screened DEmiRs and DEGs. Further analysis was carried out to obtain the hub genes through the analysis of biological pathways and enrichment pathways of DEGs targeted by DEmiRs and the construction of a protein-protein interaction (PPI) network. Results: The five differential molecules (miR-34b/c-5p, Cd14, Cxcl10, and Rhoh) were verified through in vivo experiments that had the same expression trend in the acute and chronic phases of RSV infection. Following infection of BEAS-2B cells with RSV, we confirmed that RSV infection down-regulated miR-34b/c-5p, and up-regulated the expression levels of CXCL10 and CD14. Furthermore, the results of the dual-luciferase reporter assay showed that CXCL10 was the target of hsa-miR-34c-5p. Conclusions: miR-34b/c-5p/CXCL10 axis mediates a mechanism of AHD.

Dexmedetomidine alleviates myocardial ischemia-reperfusion injury by down-regulating miR-34b-3p to activate the Jagged1/Notch signaling pathway.

BACKGROUND: Myocardial ischemia/reperfusion (I/R) injury is a fatal event that usually occurs after reperfusion therapy for myocardial infarction. Dexmedetomidine (Dex) has been shown to be beneficial in the treatment of myocardial infarction, however, its underlying mechanism for regulating I/R injury is unclear. METHODS: H9c2 cell and rat models of I/R injury were established via oxygen-glucose deprivation reoxygenation (OGD/R) and occlusion of the left anterior descending branch of coronary artery, respectively. Flow cytometry, MTT, or DHE assay detected cell activity, ROS, or apoptosis, respectively. The expression levels of miR-34b-3p and related mRNAs were determined using qRT-PCR. Related protein expression levels were detected by Western blotting and ELISA test. The interaction between miR-34b-3p and Jagged1 was assessed by dual luciferase reporter and RIP assays. The morphology of cardiac tissue was examined by TTC, HE, and TUNEL labeling. RESULTS: Dex markedly inhibited the inflammatory damage and apoptosis caused by OGD/R in H9c2 cells. MiR-34b-3p and Jagged1 levels were increased and decreased in myocardial I/R injury model, respectively, while Dex reversed this effect. Moreover, miR-34b-3p was firstly reported to directly bind and decrease Jagged1 expression, thereby inhibiting Notch signaling pathway. Transfection of agomiR-34b-3p or Jagged1 silencing eliminated Dex's defensive impact on OGD/R-induced cardiomyocytes damage. Dex relieved the myocardial I/R injury of rats via inhibiting miR-34b-3p and further activating Notch signaling pathway. CONCLUSION: Dex protected myocardium from I/R injury via suppressing miR-34b-3p to activate Jagged1-mediated Notch signaling pathway. Our findings revealed a novel mechanism underlying of Dex on myocardial I/R injury.

Role of microRNA-34b-5p in cancer and injury: how does it work?

MicroRNAs (miRNAs or miRs) are a class of noncoding single-stranded RNAs that can regulate gene expression by binding to the untranslated sequences at the 3 ' end of messenger RNAs. The microRNA-34 family is dysregulated in various human diseases. It is considered as a tumor-suppressive microRNA because of its synergistic effect with the well-known tumor suppressor p53. As a member of the miRNA-34 family, miR-34b-5p serves as a powerful regulator of a suite of cellular activities, including cell growth, multiplication, development, differentiation, and apoptosis. It promotes or represses disease occurrence and progression by participating in some important signaling pathways. This review aimed to provide an overview and update on the differential expression and function of miR-34b-5p in pathophysiologic processes, especially cancer and injury. Additionally, miR-34b-5p-mediated clinical trials have indicated promising consequences for the therapies of carcinomatosis and injury. With the application of the first tumor-targeted microRNA drug based on miR-34a mimics, it can be inferred that miR-34b-5p may become a crucial factor in the therapy of various diseases. However, further studies on miR-34b-5p should shed light on its involvement in disease pathogenesis and treatment options.

Analysis of the p53/microRNA Network in Cancer.

MicroRNAs (miRNAs) are important components of the signaling cascades that mediate and regulate tumor suppression exerted by p53. This review illustrates some of the main principles that underlie the mechanisms by which miRNAs participate in p53's function and how they were identified. Furthermore, the current status of the research on the connection between p53 and miRNAs, as well as alterations in the p53/miRNA pathways found in cancer will be summarized and discussed. In addition, experimental and bioinformatic approaches which can be applied to study the connection between p53 and miRNAs are described. Although, some of the central miRNA-encoding genes that mediate the effects of p53, such as the miR-34 and miR-200 families, have been identified, much more analyses remain to be performed to fully elucidate the connections between p53 and miRNAs.

MicroRNA-34b-5p targets PPP1R11 to inhibit proliferation and promote apoptosis in cattleyak Sertoli cells by regulating specific signaling pathways.

Cattleyaks, a hybrid of (♂) and yak (♀), exhibit the marked productivity and adaptability of plateau, but suffer from male infertility. Small non-coding RNAs, especially miRNAs, play crucial roles in spermatogenesis and affect the growth of Sertoli cells (SCs). The objective of the present study was to explore the interaction between miR-34b-5p and protein phosphatase 1 regulatory inhibitor subunit 11 (PPP1R11) and its effect on cattleyak SCs. RT-qPCR was used to determine the expression pattern of miR-34b-5p and PPP1R11, while the cellular and subcellular localization of PPP1R11 was determined by immunohistochemistry and immunocytochemistry. The interaction between MiR-34b-5p and PPP1R11 was evaluated by immunofluorescence, proliferation, apoptosis, and western blotting assays. The potential binding sites between miR-34b-5p and PPP1R11 were uncovered through targeted search of an online database, and verified using a dual luciferase reporter system. Our data show that miR-34b-5p is differentially expressed in the testes and SCs of cattleyaks compared to yaks. Overexpression of miR-34b-5p in SCs suppressed proliferation and induced apoptosis, while the effects of miR-34b-5p knockdown were the reverse. The 3'UTR of PPP1R11 was identified as a potential target site of miR-34b-5p, and this was validated by online database searches and our data from the dual-luciferase reporter assay, and it displayed an inverse expression pattern to miR-34b-5p in SCs. The effects of silencing PPP1R11 by siRNA were similar to the results of miR-34b-5p upregulation, but significantly different from miR-34b-5p downregulation in cattleyak SCs. The effects with PPP1R11 overexpression were opposite, suggesting a novel biofunctional role of PPP1R11 inactivation in depressing cattleyak SCs growth. Lastly, we confirmed that miR-34b-5p inhibited PPP1R11 expression and induced apoptosis by regulating proliferation- and apoptosis-related genes in SCs. Thus, miR-34b-5p regulates the apoptosis and proliferation of cattleyak SCs via targeting PPP1R11, which can provide an innovative direction for exploring the mechanism of cattleyak male sterility.

MiR-34b/c play a role in early sex differentiation of Amur sturgeon, Acipenser schrenckii.

BACKGROUND: Sex differentiation can be viewed as a controlled regulatory balance between sex differentiation-related mRNAs and post-transcriptional mechanisms mediated by non-coding RNAs. In mammals, increasing evidence has been reported regarding the importance of gonad-specific microRNAs (miRNAs) in sex differentiation. Although many fishes express a large number of gonadal miRNAs, the effects of these sex-biased miRNAs on sex differentiation in teleost fish remain unknown. Previous studies have shown the exclusive and sexually dimorphic expression of miR-34b/c in the gonads of the Amur sturgeon (Acipenser schrenckii), suggesting its potential role in the sex differentiation process. RESULTS: Using quantitative real-time PCR (qPCR), we observed that miR-34b/c showed consistent spatiotemporal expression patterns; the expression levels significantly increased during early sex differentiation. Using in situ hybridization, miR-34c was found to be located in the germ cells. In primary germ cells in vitro, the group subjected to overexpression and inhibition of miR-34c showed significantly higher proliferation ability and lower apoptosis, respectively, compared to the corresponding control group. Luciferase reporter assays using the ar-3'UTR-psiCHECK-2 luciferase vector suggested a targeted regulatory interaction between miR-34b/c and the 3'UTR of the androgen receptor (ar) mRNA. Furthermore, miR-34b/c and ar showed negative expression patterns during early sex differentiation. Additionally, a negative feedback regulation pattern was observed between foxl2 expression in the ovaries and amh and sox9 expression in the testes during early sex differentiation. CONCLUSIONS: This study sheds new light on the roles of miR-34b/c in gonad development of Amur sturgeon, and provides the first comprehensive evidence that the gonad-predominant microRNAs may have a major role in sex differentiation in teleost fish.