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.

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.

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.

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.

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.

Association between Genetic Polymorphisms in MicroRNAs 196a2 (rs11614913) and 34 b/c (rs4938723) and Risk of Hepatocellular Carcinoma in Egyptian Patients.

BACKGROUND: Hepatocellular carcinoma (HCC) is a common cancer with substantial cancer-related deaths worldwide. Deregulation of some genetic polymorphisms has been identified in HCC. OBJECTIVE: We aimed to demonstrate the frequency of miRNA 196a2 rs11614913 and miRNA 34 b/c rs4938723 gene polymorphisms in HCC patients and their correlation with the clinical features and laboratory findings at diagnosis. SUBJECTS AND METHODS: The study was performed on 40 patients with newly diagnosed HCC and 40 patients with liver cirrhosis in addition to 40 age and sex-matched healthy controls. Detection of miRNA 196a2 rs11614913 and miRNA 34 b/c rs4938723 gene polymorphisms was determined by PCR-RFLP. RESULTS: HCC patients had significantly higher frequency of miR-196-2a rs11614913 CC genotype when compared with cirrhotic patients (60.0 % versus 30.0 %, p=0.013). In spite of the fact that HCC patients also had higher frequency of miR-196-2a rs11614913 CC genotype in comparison to controls, the difference fell short of statistical significance (60.0 % versus 42.5 %, p=0.18). No significant differences were found between the studied groups regarding the frequency of miR-196-2a alleles. miR34 b/c rs4938723 CC genotype was the only identified genotype in all participants in the three studied groups. No significant associations were found between the different clinical and laboratory variables and genotypic variations in HCC patients. CONCLUSIONS: This study identified miR-196a2 rs11614913 CC genotype as a risk factor for HCC development while we failed to document similar relation for miR-34b/c rs4938723 polymorphism.

Altered White Matter and microRNA Expression in a Murine Model Related to Williams Syndrome Suggests That miR-34b/c Affects Brain Development via Ptpru and Dcx Modulation.

Williams syndrome (WS) is a multisystem neurodevelopmental disorder caused by a de novo hemizygous deletion of ~26 genes from chromosome 7q11.23, among them the general transcription factor II-I (GTF2I). By studying a novel murine model for the hypersociability phenotype associated with WS, we previously revealed surprising aberrations in myelination and cell differentiation properties in the cortices of mutant mice compared to controls. These mutant mice had selective deletion of Gtf2i in the excitatory neurons of the forebrain. Here, we applied diffusion magnetic resonance imaging and fiber tracking, which showed a reduction in the number of streamlines in limbic outputs such as the fimbria/fornix fibers and the stria terminalis, as well as the corpus callosum of these mutant mice compared to controls. Furthermore, we utilized next-generation sequencing (NGS) analysis of cortical small RNAs' expression (RNA-Seq) levels to identify altered expression of microRNAs (miRNAs), including two from the miR-34 cluster, known to be involved in prominent processes in the developing nervous system. Luciferase reporter assay confirmed the direct binding of miR-34c-5p to the 3'UTR of PTPRU-a gene involved in neural development that was elevated in the cortices of mutant mice relative to controls. Moreover, we found an age-dependent variation in the expression levels of doublecortin (Dcx)-a verified miR-34 target. Thus, we demonstrate the substantial effect a single gene deletion can exert on miRNA regulation and brain structure, and advance our understanding and, hopefully, treatment of WS.

Distinct roles of miR-34 family members on suppression of lung squamous cell carcinoma.

miR-34, whose mimic was used on phase I clinical trial, has been extensively reported since its dysfunction in various cancers including non-small-cell lung cancer (NSCLC). However, the roles of miR-34 family members in the progression of lung squamous carcinoma (SCC) in patients who have occupational-exposure experience are unclear yet. Here, we comprehensively investigated the expression levels of miR-34 family members in SCC patients and compared the roles of them in SCC in vitro and vivo. The results showed that the average levels of miR-34a and miR-34b/c were decreased in patients. The analysis of miR-34a to miR-34b/c levels in patients graded different stages or metastases or recurrence showed that miR-34b/c was reduced earlier and more significantly than miR-34a. In vitro assays demonstrated that both miR-34a and miR-34b/c inhibits SCC cells proliferation, migration and invasion via Notch1 pathway, while miR-34b/c effects more than miR-34a does. As miR-34a was significantly decreased in cancer recurrence, the further analysis of relationship between miR-34a and stem cell adhesion molecular CD44 showed that miR-34a was significantly correlated with CD44 levels in patients. Knockdown of CD44 significantly blocked miR-34a mediated inhibition of cell migration and invasion. Treating the purified CD44hi cells with miR-34 overexpression lentivirus inhibited the tumor outgrowth. By contrast, anti-miR-34 facilitated tumor development of CD44low cells. Our study showed that miR-34 family members are negative regulator for SCC development, even though the inhibition is mediated by multiple and complicated signal pathways, which provides theoretical basis for SCC treatment and a biomarker candidate for SCC prognosis.

The comprehensive landscape of miR-34a in cancer research.

MicroRNA-34 (miR-34) plays central roles in human diseases, especially cancers. Inactivation of miR-34 is detected in cancer cell lines and tumor tissues versus normal controls, implying its potential tumor-suppressive effect. Clinically, miR-34 has been identified as promising prognostic indicators for various cancers. In fact, members of the miR-34 family, especially miR-34a, have been convincingly proved to affect almost the whole cancer progression process. Here, a total of 512 (miR-34a, 10/21), 85 (miR-34b, 10/16), and 114 (miR-34c, 10/14) putative targets of miR-34a/b/c are predicted by at least ten miRNA databases, respectively. These targets are further analyzed in gene ontology (GO), KEGG pathway, and the Reactome pathway dataset. The results suggest their involvement in the regulation of signal transduction, macromolecule metabolism, and protein modification. Also, the targets are implicated in critical signaling pathways, such as MAPK, Notch, Wnt, PI3K/AKT, p53, and Ras, as well as apoptosis, cell cycle, and EMT-related pathways. Moreover, the upstream regulators of miR-34a, mainly including transcription factors (TFs), lncRNAs, and DNA methylation, will be summarized. Meanwhile, the potential TF upstream of miR-34a/b/c will be predicted by PROMO, JASPAR, Animal TFDB 3.0, and GeneCard databases. Notably, miR-34a is an attractive target for certain cancers. In fact, miR-34a-based systemic delivery combined with chemotherapy or radiotherapy can more effectively control tumor progression. Collectively, this review will provide a panorama for miR-34a in cancer research.

Cyclophosphamide suppresses spermatogenesis in the testis of mice through downregulation of miR-34b and miR-34c.

Cyclophosphamide (CP) is commonly used as an anticancer agent but has been associated with high toxicity in several organs, including the testes. In this study, we aimed to evaluate the effects of CP-induced testicular toxicity, using glial cell line-derived neurotrophic factor (GDNF), occludin and transforming growth factor beta 3 (TGF-ß3) primary antibodies, and miR-34b and miR-34c expressions. Eighteen young Balb/c male mice were divided into three groups. The control group received no treatment. The mice of CP group were injected 100 mg kg-1  day-1 CP for 5 days, and the same amount of saline was injected in the sham group. The animals were sacrificed 24 hr after the last injection. Immunohistochemical analysis of testicular tissues showed a decrease in both spermatogenic germ cell count and also GDNF, occludin expressions, but an increase in TGF-ß3 expression in the CP group compared to the others group. The expressions of miR-34b and miR-34c were examined by qPCR technique, a significant decrease was observed in tissue samples in the CP-treated group. The expression of GDNF, occludin and TGF-ß3 plays an important role in testicular injury caused by CP, and the decrease in the expression of miR-34b/c in tissue samples may be an important marker for the detection of testicular damage.

Up-regulation of miR-34b/c by JNK and FOXO3 protects from liver fibrosis.

α1-Antitrypsin (AAT) deficiency is a common genetic disease presenting with lung and liver diseases. AAT deficiency results from pathogenic variants in the SERPINA1 gene encoding AAT and the common mutant Z allele of SERPINA1 encodes for Z α1-antitrypsin (ATZ), a protein forming hepatotoxic polymers retained in the endoplasmic reticulum of hepatocytes. PiZ mice express the human ATZ and are a valuable model to investigate the human liver disease of AAT deficiency. In this study, we investigated differential expression of microRNAs (miRNAs) between PiZ and control mice and found that miR-34b/c was up-regulated and its levels correlated with intrahepatic ATZ. Furthermore, in PiZ mouse livers, we found that Forkhead Box O3 (FOXO3) driving microRNA-34b/c (miR-34b/c) expression was activated and miR-34b/c expression was dependent upon c-Jun N-terminal kinase (JNK) phosphorylation on Ser574 Deletion of miR-34b/c in PiZ mice resulted in early development of liver fibrosis and increased signaling of platelet-derived growth factor (PDGF), a target of miR-34b/c. Activation of FOXO3 and increased miR-34c were confirmed in livers of humans with AAT deficiency. In addition, JNK-activated FOXO3 and miR-34b/c up-regulation were detected in several mouse models of liver fibrosis. This study reveals a pathway involved in liver fibrosis and potentially implicated in both genetic and acquired causes of hepatic fibrosis.

Associations of Common Single Nucleotide Polymorphisms in miR-34b/c and miR-499 with Male Infertility Caused by Oligospermia or Azoospermia in the Chinese Population.

Aims: The present study was designed to survey the associations between polymorphisms of the common single nucleotide polymorphism (SNP) rs4938723 in the miR-34b/c gene, as well as the rs3746444 SNP in the miR-499 gene, and impairment of spermatogenesis leading to oligospermia and azoospermia in the Chinese population. Subjects and Methods: Specimens were collected from four hundred seventeen infertile men with oligospermia or azoospermia and 234 controls for this investigation. Polymerase chain reaction and restriction fragment length polymorphism analyses was used for genotyping the rs4938723 and rs3746444 SNPs. A chi-square analysis was used to compare the differences in allelic and genotypic frequencies between patients and controls. Results: The distribution of alleles at the rs3746444 locus of the miR-499 gene in patients was not significantly different from controls. There were, however, significant differences in the genotypic (p = 0.040) and allelic (p = 0.021) distributions of the rs4938723 SNPs between patients with oligospermia and controls. The CC genotype at the rs4938723 locus was significantly higher in in patients with oligospermia than controls (13.9% vs. 7.3%, p = 0.016, odds ratio = 2.064, 95% confidence interval 1.132-3.764). Conclusion: The CC genotype of the rs4938723 locus in the miR-34b/c gene may enhance susceptibility to oligospermia.

Association of TP53 rs1042522 C>G and miR-34b/c rs4938723 T>C polymorphisms with hepatoblastoma susceptibility: A seven-center case-control study.

BACKGROUND: Hepatoblastoma is a rare malignancy originating from pluripotent stem cells with unknown etiology. An understanding of the etiology in pediatric hepatoblastoma has been hampered by the unavailability of sufficient patient samples. To date, only a few epidemiological studies with small sample sizes have been performed investigating risk factors for hepatoblastoma. TP53 and pri-miR-34b/c genes are implicated in the tumorigenesis, yet the role of their polymorphisms in hepatoblastoma susceptibility remains unknown. METHODS: We conducted a seven-center case-control study to explore the genetic variants predisposing to hepatoblastoma susceptibility. In our study, we genotyped two functional polymorphisms, the TP53 rs1042522 C>G (Arg72Pro) and miR-34b/c rs4938723 T>C, in 313 cases and 1446 controls using the TaqMan method. RESULTS: Single loci analysis showed that neither TP53 rs1042522 C>G, nor miR-34b/c rs4938723 T>C significantly modified hepatoblastoma risk. In the stratification analysis, we identified that the miR-34b/c rs4938723 TC/CC genotypes were associated with a decreased risk in patients with clinical stages III + IV hepatoblastoma (adjusted odds ratio = 0.53, 95% confidence interval = 0.33-0.84, P=0.007] compared to the rs4938723 TT genotype. Subsequent analysis further showed that the combination of TP53 and miR-34b/c variant genotypes had no impact on susceptibility hepatoblastoma. CONCLUSIONS: Taken together, TP53 rs1042522 C>G and miR-34b/c rs4938723 T>C may not confer hepatoblastoma susceptibility. These findings may aid in our understanding of the genetic etiology of hepatoblastoma.

The association of miR34b/c and TP53 gene polymorphisms with Wilms tumor risk in Chinese children.

Wilms tumor is the most common pediatric malignancy in the kidney. The miR34b/c is a downstream target gene of the transcription factor p53. The important role of TP53 mutations, the methylation of miR34b/c, and the interaction between these two molecules in tumorigenesis have been well documented. Due to the biological connection between p53 and miR34b/c, in the present study, we investigated the association between polymorphisms in these two molecules and Wilms tumor susceptibility through genotyping two important functional polymorphisms (miR34b/c rs4938723 T>C and TP53 rs1042522 C>G) in 183 cases and 603 controls. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) derived from the logistic regression analysis were used to assess the correlation of miR34b/c rs4938723 and TP53 rs1042522 polymorphisms with Wilms tumor risk. Our results indicated that the association of miR34b/c rs4938723 and TP53 rs1042522 polymorphisms with Wilms tumor susceptibility was not statistically significant. Stratified analysis by age, gender, and clinical stage, as well as combined effect analysis were also performed, yet, no significant association was found. In conclusion, our study indicated a lack of association between the two selected polymorphisms and Wilms tumor susceptibility. Our findings need to be verified in studies with larger sample size in the future.

miR-34b/c regulates doxorubicin-induced myocardial cell injury through ITCH.

Objective: To determine the underlying mechanism of miR-34b/c in regulating doxorubicin (Dox)-induced myocardial cell injury.Methods: The viability of mouse myocardial cells HL-1 was detected by MTT assay. The apoptosis of HL-1 cells was detected by TUNEL assay. mRNA expressions of ITCH, TNF-α and IL-6 were measured by qRT-PCR. Protein levels of ITCH, NF-κB, TNF-α and IL-6 were measured by western blot. Dual luciferase assay was performed to detect the regulation of miR-34b/c on ITCH. Mouse model of cardiomyopathy was induced by intraperitoneal injection of Dox.Results: Dox reduced HL-1 cell viability and activated NF-κB pathway in HL-1 cells. miR-34b/c expressions were gradually up-regulated and ITCH expression was gradually down-regulated in Dox-treated HL-1 cells. miR-34b/c expression had negative correlation with the mRNA expression of ITCH. Besides, ITCH was a target of miR-34b/c. miR-34b/c mimic reduced cell viability, suppressed ITCH expression, increased TNF-α and IL-6 level, and promoted NF-κB expression in nucleus and cytoplasm of HL-1 cells. Whereas silencing miR-34 protected HL-1 cells through regulating ITCH. Finally, we demonstrated miR-34 antagomir-protected myocardial cells in mouse model of cardiomyopathy.Conclusion: miR-34b/c decreased HL-1 cell viability and promoted the secretion of proinflammatory cytokines in Dox-induced myocardial cells through ITCH/NF-κB pathway.

Pri-miR-34b/c rs4938723 Polymorphism Contributes to Coronary Artery Disease Susceptibility.

OBJECTIVES: Accumulating evidences have shown that polymorphisms in miRNA genes play an important role in the susceptibility to coronary artery disease (CAD). A potentially functional polymorphism rs4938723, which located within the promoter region of pri-miR-34b/c, may affect the expression of miR-34b/c. To date, the role of genetic variant in pri-miR-34b/c on CAD risk is still unknown. Here we aimed to evaluate the association of Pri-miR-34b/c rs4938723 polymorphism with individual susceptibility to CAD in a Chinese Han population. METHODS: Genotyping was performed in a case-control study of 563 patients and 646 controls using polymerase chain reaction-ligase detection reaction (PCR-LDR) method. The association of rs4938723 with CAD risk was evaluated using logistic regression analysis with SPSS software. RESULTS: We found that the C allele of pri-miR-34b/c rs4938723 was significantly associated with a decreased risk of CAD when compared with the T allele (OR = 0.76, 95% CI = 0.62-0.95, p = 0.015). Consistently, compared with those carrying TT genotype, the CC homozygotes displayed significantly reduced risk for CAD (OR = 0.54, 95% CI = 0.32-0.91, p = 0.021). Similar trend of the reduced risk for CAD was detected when the CT and CC genotypes were combined (OR = 0.75, 95% CI = 0.57-0.99, p = 0.044). Stratified analysis of pri-miR-34b/c rs4938723 revealed a more significant association of C allele with decreased CAD risk among older subjects, male and non-smokers. CONCLUSIONS: Our findings suggest that the pri-miR-34b/c rs4938723 polymorphism is associated with CAD susceptibility in the Chinese Han population. Further studies are warranted to confirm the general validity of our findings.

Pri-miR-34b/c rs4938723 Polymorphism is Associated with Decreased Risk and Better Prognosis for Colorectal Cancer Patients.

BACKGROUND: Colorectal cancer (CRC) is a major cause of cancer-related deaths worldwide. miR-34 induces changes of its downstream genes and plays a key role in altering the apoptotic cycle and pathways of downstream cells and therefore influences carcinogenesis. OBJECTIVE: The present study investigated whether the single nucleotide polymorphism rs4938723T > C in the promoter of region of miR-34b/c may increase the risk of CRC and influence outcome in patients with CRC. METHODS: We enrolled 1078 CRC patients and 1175 cancer-free controls subjects from the Chinese population. miR-34b/c rs4938723T > C polymorphisms were genotyped using a TaqMan PCR method. RESULTS: We found that subjects carrying rs4938723CT/CC genotypes have significantly decreased risk of CRC (adjusted odds ratios (AOR) = 0.75, 95% CI (0.63-0.90) for CT vs.TT; AOR = 0.61, 95% CI (0.46-0.83) for CC vs. TT and AOR = 0.73,95% CI (0.61-0.86) for CT/CC vs. TT) and a significant increased median survival time (MST) compared with those with TT genotypes (MST = 96.500; 75.883 and 71.370 months for CT, CC and CT/CC respectively vs. MST = 54.300 months for TT, p <0.0001). Stratified analysis by both life style and clinicopathological risks revealed that subjects carrying rs4938723CT/CC genotypes were remained significantly associated with increased survival and low risk of CRC compared with those with TT genotypes in all subgroup (all p <0.05). Similar observation was also reported for the prognostic value of rs4938723TC/CC genotypes across all subgroups. CONCLUSION: These findings indicate that the miR-34b/c rs4938723T > C polymorphism is an independent variable and associated with a decreased risk of CRC in Chinese population. This study provides evidence of the protective effects of rs4938723CT/CC genotypes in the development of CRC.

Hypermethylation of miR-34b/c is associated with early clinical stages and tumor differentiation in Kazakh patients with esophageal squamous cell carcinoma.

DNA hypermethylation in tumor suppressor genes has been reported in some cancers. The microRNA-34b/c (miR-34b/c) serves as tumor suppressors in different tumor types. To investigate the methylation status of miR-34b/c in ESCC, MALDI-TOF MS was used to quantitatively analyze the DNA methylation of 16 CpG sites within miR-34b/c in 145 ESCC samples, 60 cancer-adjacent normal (ACN) samples and 39 normal esophageal (NE) samples from the Kazakh population. Our results showed that the overall average methylation levels of miR-34b/c were significantly higher in the ESCC samples than they were in the ACN and NE samples (P < 0.05). Furthermore, the methylation levels of CpG_1.2.3, CpG_9.10, CpG_11.12.13, CpG_14, and CpG_15.16 of miR-34b/c were significantly higher in the ESCC tissues than they were in the ACN (P < 0.05) and NE tissues (P < 0.05). Additionally, the mean methylation levels at CpG_9.10 and CpG_14 were all significantly higher in the ACN samples than they were in the NE samples (P < 0.01). Increased methylation levels of CpG_9.10 and CpG_11.12.13 in miR-34b/c predominantly occurred in the early stages (UICC I/II) of ESCC (P < 0.05), and the methylation differences (moderately-poorly differentiated > well differentiated) in miR-34b/c CpG_1.2.3 were significant (P < 0.05). This is the first study reporting that the hypermethylation of miR-34b/c plays an important role in ESCC and is significantly correlated with the early stages and tumor differentiation of ESCC. The hypermethylation of miR-34b/c may promote the oncogenesis and progression of ESCC, and these findings may provide support for the future development of targeted therapies.