miR-7-5p overexpression suppresses cell proliferation and promotes apoptosis through inhibiting the ability of DNA damage repair of PARP-1 and BRCA1 in TK6 cells exposed to hydroquinone

Vitamin D receptor polymorphisms and associated miRNAs in the development of breast cancer in African American women

Breast cancer (BCa) is a prevalent form of cancer in women, exhibiting varying rates and distribution across different ethnic groups. Among these groups, African American (AA) women have the highest incidence of BCa and the lowest levels of Vitamin D (VD). Numerous studies have explored the connection between variations in the VDR gene and BCa risk, particularly in different populations, but research on the AA population remains limited. Epigenetic modifications, including specific microRNAs (miRNAs), can influence gene expression without altering the genetic code and have been implicated in cancer initiation and progression. Our hypothesis suggests that VDR gene variations may increase BCa risk in AA women and that changes in miRNA expression profiles could contribute to BCa development. Using data from the 1000 Genome Project, we identified five VDR gene variants with significant frequency differences between AA and European-American (EA) populations. We genotyped 404 African American BCa cases and controls for five variants using TaqMan® assays. SNPstats assessed their association with BCa risk. The rs1544410 variant's recessive model (A/A) showed a decreased BCa risk in AA (odds ratio 0.33, 95% CI: 0.15-0.73, p-value 0.0041). Conversely, the rs2853563 variant's recessive model (A/A) was linked to an increased BCa risk (odds ratio 4.04, 95% CI: 1.49-10.95, p-value 0.0022). We investigated miRNA expression influenced by VD in HCC1806 Triple-Negative Breast Cancer (TNBC) cell lines with the A/A allele for rs2853563. nCounter® Nanostring technology assessed miRNA profiles after calcitriol treatment. Our results indicated that calcitriol treatment led to reduced expression of six miRNAs, four of which are associated with tumor suppression in the presence of the AA genotype in TNBC cell lines. These findings suggest that specific VDR genotypes could have a potential effect on the miRNAs expression which could potentially serve as markers for cell proliferation in TNBC.

Linc01588 deletion inhibits the malignant biological characteristics of hydroquinone-induced leukemic cells via miR-9-5p/SIRT1

Leukemia caused by environmental chemical pollutants has attracted great attention, the malignant leukemic transformation model of TK6 cells induced by hydroquinone (HQ) has been previously found in our team. However, the type of leukemia corresponding to this malignant transformed cell line model needs further study and interpretation. Furthermore, the molecular mechanism of malignant proliferation of leukemic cells induced by HQ remains unclear. This study is the first to reveal the expression of aberrant genes in leukemic cells of HQ-induced malignant transformation, which may correspond to chronic lymphocytic leukemia (CLL). The expression of Linc01588, a long non-coding RNA (lncRNA), was significantly up-regulated in CLL patients and leukemic cell line model which previously described. After gain-of-function assays and loss-of-function assays, feeble cell viability, severe apoptotic phenotype and the increased secretion of TNF-α were easily observed in malignant leukemic TK6 cells with Linc01588 deletion after HQ intervention. The tumors derived from malignant TK6 cells with Linc01588 deletion inoculated subcutaneously in nude mice were smaller than controls. In CLL and its cell line model, the expression of Linc01588 and miR-9-5p, miR-9-5p and SIRT1 were negative correlation respectively in CLL and cell line model, while the expression of Linc01588 and SIRT1 were positive correlation. The dual-luciferase reporter assay showed that Linc01588 & miR-9-5p, miR-9-5p & SIRT1 could bind directly, respectively. Furthermore, knockdown of miR-9-5p successfully rescued the severe apoptotic phenotype and the increased secretion of TNF-α caused by the Linc01588 deletion, the deletion of Linc01588 in human CLL cell line MEC-2 could also inhibit malignant biological characteristics, and the phenotype caused by the deletion of Linc01588 could also be rescued after overexpression of SIRT1. Moreover, the regulation of SIRT1 expression in HQ19 cells by Linc01588 and miR-9-5 P may be related to the Akt/NF-κB pathway. In brief, Linc01588 deletion inhibits the malignant biological characteristics of HQ-induced leukemic cells via miR-9-5p/SIRT1, and it is a novel and hopeful clue for the clinical targeted therapy of CLL.

Blocking exosomal secretion aggravated 1,4-benzoquinone-induced cytotoxicity

Benzene exposure inhibits the hematopoietic system and leads to the occurrence of various types of leukemia. However, the mechanism underlying the hematotoxicity of benzene is still largely unclear. Emerging evidence has shown that exosomes are involved in toxic mechanisms of benzene. To understand the effect of 1,4-benzoquinone (PBQ; an active metabolite of benzene in bone marrow) on the exosomal release characteristics and role of exosomal secretion in PBQ-induced cytotoxicity. Exosomes were isolated from PBQ-treated HL-60 cells, purified by ultracentrifugation, and verified by transmission electron microscopy, nanoparticle tracking analysis and the presence of specific biomarkers. Our results showed that PBQ increased exosomal secretion in a dose-dependent manner, reaching a peak in 3 h at 10 μM PBQ treatment and then slowly decreasing in HL-60 cells. The exosomes contained miRNAs, which have been reported to be associated with benzene exposure or benzene poisoning. In particular, mir-34a-3p and mir-34A-5p were enriched in exosomes derived from PBQ-treated cells. In addition, the inhibition of exosomal release by GW4869 (an inhibitor of exosomal release) exacerbated PBQ-induced cytotoxicity, including increased intracellular reactive oxygen species levels, decreased mitochondrial membrane potential, and increased the apoptosis rate. Our findings illustrated that exosomes secretion plays an important role in antagonizing PBQ-induced cytotoxicity and maintaining cell homeostasis.

Exosomal derived miR-1246 from hydroquinone-transformed cells drives S phase accumulation arrest by targeting cyclin G2 in TK6 cells

BACKGROUND

Hydroquinone (HQ), a major metabolite of benzene and known hematotoxic carcinogen. MicroRNA 1246 (miR-1246), an oncogene, regulates target genes in carcinogenesis including leukemia. This study investigates the impact of exosomal derived miR-1246 from HQ-transformed (HQ19) cells on cell-to-cell communication in recipient TK6 cells.

METHODS

RNA sequencing was used to identify differentially expressed exosomal miRNAs in HQ19 cells and its phosphate buffered solution control cells (PBS19), which were then confirmed using qRT-PCR. The impact of exosomal miR-1246 derived from HQ-transformed cells on cell cycle distribution was investigated in recipient TK6 cells.

RESULTS

RNA sequencing analysis revealed that 34 exosomal miRNAs were upregulated and 158 miRNAs were downregulated in HQ19 cells compared with PBS19 cells. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses predicted that their targets are enriched in cancer development-related pathways, such as MAPK signaling, microRNAs in cancer, apoptosis, PI3K-Akt signaling, cell cycle, Ras signaling, and Chronic myeloid leukemia. Eleven miRNAs were confirmed to have differential expression through qRT-PCR, with 6 upregulated (miR-140-3p, miR-551b-3p, miR-7-5p, miR-1290, miR-92a-3p, and miR-1246) and 5 downregulated (miR-183-5p, miR-26a-5p, miR-30c-5p, miR-205-5p, and miR-99b-3p). Among these, miR-1246 exhibited the highest expression level. HQ exposure resulted in a concentration-dependent increase in miR-1246 levels and decrease Cyclin G2 (CCNG2) levels in TK6 cells. Similarly, exosomes from HQ19 exhibited similar effects as HQ exposure. Dual luciferase reporter gene assays indicated that miR-1246 could band to CCNG2. After HQ exposure, exosomal miR-1246 induced cell cycle arrest at the S phase, elevating the expression of genes like pRb, E2F1, and Cyclin D1 associated with S phase checkpoint. However, silencing miR-1246 caused G2/M-phase arrest.

CONCLUSION

HQ-transformed cells' exosomal miR-1246 targets CCNG2, regulating TK6 cell cycle arrest, highlighting its potential as a biomarker for HQ-induced malignant transformation.

Non-coding RNAs: A new frontier in benzene-mediated toxicity

One of the most frequent environmental contaminants, benzene is still widely used as an industrial solvent around the world, especially in developing nations, posing a serious occupational risk. While the processes behind the toxicity of benzene grounds are not fully understood, it is generally accepted that its metabolism, which involves one or more reactive metabolites, is crucial to its toxicity. In order to evaluate the many ways that benzene could influence gene regulation and thus have an impact on human health, new methodologies have been created. The pathophysiology of the disorder may result from epigenetic reprogramming caused by exposure to benzene, including changes in non-coding RNA (ncRNA) markers, according to recent studies. We are interested in the identification of hazardous regulatory ncRNAs, the identification of these ncRNAs' targets, and the comprehension of the significance of these interactions in the mechanisms behind benzene toxicity. Hence, the focus of recent research is on long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) and microRNAs (miRNAs), and some of the more pertinent articles are also discussed.

JNK1 activated pRb/E2F1 and inhibited p53/p21 signaling pathway is involved in hydroquinone-induced pathway malignant transformation of TK6 cells by accelerating the cell cycle progression

Hydroquinone (HQ) is an important metabolites of benzene in the body, and it has been found to result in cellular DNA damage, mutation, cell cycle imbalance, and malignant transformation. The JNK1 signaling pathway plays an important role in DNA damage repair. In this study, we focused on whether the JNK1 signaling pathway is involved in the HQ-induced cell cycle abnormalities and the underlying mechanism. The results showed that HQ induced abnormal progression of the cell cycle and initiated the JNK1 signaling pathway. We further confirmed that JNK1 suppression decelerated the cell cycle progression through inhibiting pRb/E2F1 signaling pathway and triggering p53/p21 pathway. Therefore, we concluded that JNK1 might be involved in HQ-induced malignant transformation associated with activating pRb/E2F1 and inhibiting p53/p21 signaling pathway which resulting in accelerating the cell cycle progression.

miR-7-5p Antagomir Protects Against Inflammation-Mediated Apoptosis and Lung Injury via Targeting Raf-1 In Vitro and In Vivo

Exacerbated inflammation and apoptosis are considered upstream events associated with acute lung injury (ALI). microRNAs are critical regulators of genes responsible for inflammation and apoptosis and are considered potential therapeutic targets for ameliorating ALI. This study was undertaken to uncover the role of miR-7-5p in LPS-induced lung injury. A LPS-induced inflammation model was established using BEAS-2B cells and C57BL/6 mice. Bioinformatics analysis and the luciferase reporter assay confirmed that Raf-1 is a target of miR-7-5p and that its expression was inversely correlated with expression of proinflammatory markers and miR-7-5p, whereas miR-7-5p inhibition in vitro led to subsequent restoration of Raf-1 expression and prevention of apoptosis. Intranasal (i.n.) administration of antagomir using the C57BL/6 mouse model further confirmed that miR-7-5p inhibition suppresses LPS-induced inflammation and apoptosis via modulating the miR-7-5p/Raf-1 axis. Our findings indicate that blocking miR-7-5p expression by antagomir protects mice from LPS-induced lung injury by suppressing inflammation and activation of mitochondria-mediated survival signalling. In conclusion, our findings demonstrate a previously unknown pathophysiological role of miR-7-5p in the progression of ALI, and targeted i.n. administration of miR-7-5p antagomir could aid in the development of potential therapeutic strategies against lung injury.

BC-miR: Monitoring Breast Cancer-Related miRNA Profile in Blood Sera—A Prosperous Approach for Tumor Detection

Breast cancer is the most frequent cancer with a high fatality rate amongst women worldwide. Diagnosing at an early stage is challenging, and due to the limitations of the currently used techniques, including mammography and imaging diagnostics, it still remains unascertained. Serum biomarkers can be a solution for this as they can be isolated in a less painful, more cost-effective, and minimally invasive manner. In this study, we shed light on the relevant role of multiple microRNAs (miRNAs) as potential biomarkers in breast cancer diagnosis. We monitored the expressional changes of 15 pre-selected miRNAs in a large cohort, including 65 patients with breast cancer and 42 healthy individuals. We performed thorough statistical analyses on the cohort sample set and determined the diagnostic accuracy of individual and multiple miRNAs. Our study reveals a potential improvement in diagnostics by implicating the monitoring of miR-15a+miR-16+miR-221 expression in breast cancer management.

PARP-1 modulates the expression of miR-223 through histone acetylation to involve in the hydroquinone-induced carcinogenesis of TK6 cells

The upstream regulators of microRNAs were rarely reported. Hydroquinone (HQ) is the main metabolite of benzene, one of the important environmental factors contributing to leukemia and lymphoma. In HQ-induced malignant transformed TK6 (TK6-HT) cells, the expression of PARP-1 and miR-223 were upregulated. When in PARP-1 silencing TK6-HT cells, miR-223 was downregulated and the apoptotic cell number correspondingly increased. In TK6 cells treated with HQ for different terms, the expression of miR-223 and PARP-1 were dynamically observed and found to be decreased and increased, respectively. Trichostatin A could increase the expression of miR-223, then the expression of HDAC1-2 and nuclear factor kappa B were found to be increased, but that of mH2A was decreased. PARP-1 silencing inhibited the protein expression of H3Ac, mH2A, and H3K27ac. By co-immunoprecipitation experiment, PARP-1 and HDAC2 were found to form a regulatory complex. In conclusion, we demonstrated that the upregulation of PARP-1 mediated activation of acetylation to promote the transcription of miR-223 possibly via coregulating with HDAC2, an epigenetic regulation mechanism involved in cell malignant transformation resulting from long-term exposure to HQ, in which course, H3K27ac might be a specific marker for the activation of histone H3, which also gives hints for benzene exposure research.

BRCA1 expression associated with the prognostic value of platinum-based chemotherapy for stage II-IV non-small cell lung cancer: A meta-analysis

PURPOSE

To explore the relationship between breast cancer susceptibility gene 1 (BRCA1) expression and the prognostic value of platinum-based chemotherapy for stage II-IV non-small cell lung cancer (NSCLC).

METHODS

PubMed, Web of Science, Embase, and Cochrane Library were searched from inception to August 2021, for retrieving literature related to BRCA1 expression and prognostic value of platinum-based chemotherapy in NSCLC patients. Stata 15.0 was employed for statistical analysis.

RESULTS

A total of 15 articles were included. Compared with the low BRCA1 expression, its high expression negatively affected the overall survival of NSCLC patients treated with platinum-based chemotherapy (hazard ratio (HR) = 1.53, 95% confidence interval (CI): 1.01-2.31, P < 0.05). No significant difference was identified in the effect of both low and high BRCA1 expression on event-free survival (HR = 1.73, 95% CI: 0.98-3.05, P > 0.05). Subgroup analysis showed that significant differences existed in overall survival and event-free survival in Caucasian population; that is, compared with low BRCA1 expression, its high expression negatively affected the overall survival (HR = 1.79, 95% CI: 1.15-2.79, P < 0.05) and event-free survival (HR = 2.39, 95% CI: 1.43-3.97, P < 0.05). Nevertheless, there were no significant differences in overall survival and event-free survival in China.

CONCLUSION

BRCA1 expression is correlated with the prognostic value of platinum-based chemotherapy for stage II-IV NSCLC patients. In Caucasian population, compared with low BRCA1 expression, its high expression has a negative effect on the overall survival and event-free survival in stage II-IV NSCLC patients after platinum-based chemotherapy; however, this correlation was not found in China.

Identification of potential pathways and microRNA-mRNA networks associated with benzene metabolite hydroquinone-induced hematotoxicity in human leukemia K562 cells

Background

Hydroquinone (HQ) is a phenolic metabolite of benzene with a potential risk for hematological disorders and hematotoxicity in humans. In the present study, an integrative analysis of microRNA (miRNA) and mRNA expressions was performed to identify potential pathways and miRNA-mRNA network associated with benzene metabolite hydroquinone-induced hematotoxicity.

Methods

K562 cells were treated with 40 μM HQ for 72 h, mRNA and miRNA expression changes were examined using transcriptomic profiles and miRNA microarray, and then bioinformatics analysis was performed.

Results

Out of all the differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) induced by HQ, 1482 DEGs and 10 DEMs were up-regulated, and 1594 DEGs and 42 DEMs were down-regulated. HQ-induced DEGs were involved in oxidative stress, apoptosis, DNA methylation, histone acetylation and cellular response to leukemia inhibitory factor GO terms, as well as metabolic, Wnt/β-catenin, NF-κB, and leukemia-related pathways. The regulatory network of mRNAs and miRNAs includes 23 miRNAs, 1108 target genes, and 2304 potential miRNAs-mRNAs pairs. MiR-1246 and miR-224 had the potential to be major regulators in HQ-exposed K562 cells based on the miRNAs-mRNAs network.

Conclusions

This study reinforces the use of in vitro model of HQ exposure and bioinformatic approaches to advance our knowledge on molecular mechanisms of benzene hematotoxicity at the RNA level.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00556-8.

Interactions between miRNAs and Double-Strand Breaks DNA Repair Genes, Pursuing a Fine-Tuning of Repair

The repair of DNA damage is a crucial process for the correct maintenance of genetic information, thus, allowing the proper functioning of cells. Among the different types of lesions occurring in DNA, double-strand breaks (DSBs) are considered the most harmful type of lesion, which can result in significant loss of genetic information, leading to diseases, such as cancer. DSB repair occurs through two main mechanisms, called non-homologous end joining (NHEJ) and homologous recombination repair (HRR). There is evidence showing that miRNAs play an important role in the regulation of genes acting in NHEJ and HRR mechanisms, either through direct complementary binding to mRNA targets, thus, repressing translation, or by targeting other genes involved in the transcription and activity of DSB repair genes. Therefore, alteration of miRNA expression has an impact on the ability of cells to repair DSBs, which, in turn, affects cancer therapy sensitivity. This latter gives account of the importance of miRNAs as regulators of NHEJ and HRR and places them as a promising target to improve cancer therapy. Here, we review recent reports demonstrating an association between miRNAs and genes involved in NHEJ and HRR. We employed the Web of Science search query TS (“gene official symbol/gene aliases*” AND “miRNA/microRNA/miR-”) and focused on articles published in the last decade, between 2010 and 2021. We also performed a data analysis to represent miRNA–mRNA validated interactions from TarBase v.8, in order to offer an updated overview about the role of miRNAs as regulators of DSB repair.

Characterization of the 3'UTR of the BTD gene and identification of regulatory elements and microRNAs

Reduced biotinidase activity is associated with a spectrum of deficiency ranging from total deficiency to heterozygous levels, a finding that is not always explained by the pathogenic variants observed in the BTD gene. The investigation of miRNAs, regulatory elements and variants in the 3’UTR region may present relevance in understanding the genotype-phenotype association. The aims of the study were to characterize the regulatory elements of the 3’UTR of the BTD gene and identify variants and miRNAs which may explain the discrepancies observed between genotype and biochemical phenotype. We evaluated 92 individuals with reduced biotinidase activity (level of heterozygotes = 33, borderline = 35, partial DB = 20 or total DB= 4) with previously determined BTD genotype. The 3’UTR of the BTD gene was Sanger sequenced. In silico analysis was performed to identify miRNAs and regulatory elements. No variants were found in the 3’UTR. We found 97 possible miRNAs associated with the BTD gene, 49 predicted miRNAs involved in the alanine, biotin, citrate and pyruvate metabolic pathways and 5 genes involved in biotin metabolism. Six AU-rich elements were found. Our data suggest variants in the 3'UTR of BTD do not explain the genotype-phenotype discrepancies found in Brazilian individuals with reduced biotinidase.

miRNA and lncRNA Expression Networks Modulate Cell Cycle and DNA Repair Inhibition in Senescent Prostate Cells

Cellular senescence is a state of permanent growth arrest that arises once cells reach the limit of their proliferative capacity. It creates an inflammatory microenvironment favouring the initiation and progression of various age-related diseases, including prostate cancer. Non-coding RNAs (ncRNAs) have emerged as important regulators of cellular gene expression. Nonetheless, very little is known about the interplay of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) and how deregulation of ncRNA networks promotes cellular senescence. To investigate this, human prostate epithelial cells were cultured through different passages until senescent, and their RNA was extracted and sequenced using RNA sequencing (RNAseq) and microRNA sequencing (miRNA-seq) miRNAseq. Differential expression (DE) gene analysis was performed to compare senescent and proliferating cells with Limma, miRNA-target interactions with multiMiR, lncRNA-target interactions using TCGA data and network evaluation with miRmapper. We found that miR-335-3p, miR-543 and the lncRNAs H19 and SMIM10L2A all play central roles in the regulation of cell cycle and DNA repair processes. Expression of most genes belonging to these pathways were down-regulated by senescence. Using the concept of network centrality, we determined the top 10 miRNAs and lncRNAs, with miR-335-3p and H19 identified as the biggest hubs for miRNAs and lncRNA respectively. These ncRNAs regulate key genes belonging to pathways involved in cell senescence and prostate cancer demonstrating their central role in these processes and opening the possibility for their use as biomarkers or therapeutic targets to mitigate against prostate ageing and carcinogenesis.

Epigenetic alterations induced by genotoxic occupational and environmental human chemical carcinogens: An update of a systematic literature review

Epigenetic alterations, such as changes in DNA methylation, histones/chromatin structure, nucleosome positioning, and expression of non-coding RNAs, are recognized among key characteristics of carcinogens; they may occur independently or concomitantly with genotoxic effects. While data on genotoxicity are collected through standardized guideline tests, data collected on epigenetic effects is far less uniform. In 2016, we conducted a systematic review of published studies of genotoxic carcinogens that reported epigenetic endpoints to better understand the evidence for epigenetic alterations of human carcinogens, and the potential association with genotoxic endpoints. Since then, the number of studies of epigenetic effects of chemicals has nearly doubled. This review stands as an update on epigenetic alterations induced by occupational and environmental human carcinogens that were previously and recently classified as Group 1 by the International Agency for Research on Cancer. We found that the evidence of epigenetic effects remains uneven across agents. Studies of DNA methylation are most abundant, while reports concerning effects on non-coding RNA have increased over the past 5 years. By contrast, mechanistic toxicology studies of histone modifications and chromatin state alterations remain few. We found that most publications of epigenetic effects of carcinogens were studies in exposed humans or human cells. Studies in rodents represent the second most common species used for epigenetic studies in toxicology, in vivo exposures being the most predominant. Future studies should incorporate dose- and time-dependent study designs and also investigate the persistence of effects following cessation of exposure, considering the dynamic nature of most epigenetic alterations.

MicroRNAs and the DNA damage response: How is cell fate determined?

It is becoming clear that the DNA damage response orchestrates an appropriate response to a given level of DNA damage, whether that is cell cycle arrest and repair, senescence or apoptosis. It is plausible that the alternative regulation of the DNA damage response (DDR) plays a role in deciding cell fate following damage. MicroRNAs (miRNAs) are associated with the transcriptional regulation of many cellular processes. They have diverse functions, affecting, presumably, all aspects of cell biology. Many have been shown to be DNA damage inducible and it is conceivable that miRNA species play a role in deciding cell fate following DNA damage by regulating the expression and activation of key DDR proteins. From a clinical perspective, miRNAs are attractive targets to improve cancer patient outcomes to DNA-damaging chemotherapy. However, cancer tissue is known to be, or to become, well adapted to DNA damage as a means of inducing chemoresistance. This frequently results from an altered DDR, possibly owing to miRNA dysregulation. Though many studies provide an overview of miRNAs that are dysregulated within cancerous tissues, a tangible, functional association is often lacking. While miRNAs are well-documented in 'ectopic biology', the physiological significance of endogenous miRNAs in the context of the DDR requires clarification. This review discusses miRNAs of biological relevance and their role in DNA damage response by potentially 'fine-tuning' the DDR towards a particular cell fate in response to DNA damage. MiRNAs are thus potential therapeutic targets/strategies to limit chemoresistance, or improve chemotherapeutic efficacy.

PARP-1 via regulation of p53 and p16, is involved in the hydroquinone-induced malignant transformation of TK6 cells by decelerating the cell cycle

Poly(ADP-ribose)polymerase-1 (PARP-1) plays a crucial role in DNA damage repair and could be viewed as both a tumor promoter and tumor-suppressor gene. However, the effects of PARP-1 in hydroquinone-induced malignant transformation of TK6 cells remain to be further elucidated. The present research evaluated the potential mechanism of PARP-1 in hydroquinone-induced malignant transformation of TK6 cells. The results indicated that high PARP-1 inhibited TK6 cells malignant transformation after chronic exposure to HQ. We further confirmed that PARP-1 overexpression blocked cell proliferation, and decelerated cell cycle progression in vitro and in vivo. The immunoblotting analysis indicated that PARP-1 regulated cell cycle progression via p16/Rb and p53. Therefore, we conclude that PARP-1 is involved in HQ-induced malignant transformation associated with increasing p16/Rb and p53 which resulting in decelerating the cell cycle progression.

PARP1 Is Targeted by miR-519a-3p and Promotes the Migration, Invasion, and Tube Formation of Ovarian Cancer Cells

Background: Poly ADP-ribose polymerase 1 (PARP1) has been discovered to be implicated in ovarian cancer (OC), but its interaction with microRNA (miR)-519a-3p remained poorly understood. This study aimed to uncover their roles and interactions in OC. Materials and Methods: Clinical tissue from OC patients and adjacent normal tissue were collected, and the survival rates of OC patients with high or low PARP1 expression were analyzed by Kaplan-Meier curve. After transfection, OC cell viability, migration, and tube formation were detected with cell counting kit-8 (CCK-8) assay, scratch assay, and tube formation assay, respectively. Target gene of miR-519a-3p and potential binding sites between them were predicted with TargetScan and confirmed using dual-luciferase reporter assay. Relative expressions of miR-519a-3p, PARP1, E-cadherin, N-cadherin, SNAIL, vascular endothelial growth factor (VEGF), and p53 were measured by quantitative real-time polymerase chain reaction and Western blot as needed. Results: PARP1 expression was upregulated in OC, which was related to poor prognosis of OC patients. Silencing PARP1 decreased PARP1 expression and suppressed viability, migration, invasion, and tube formation in OC cells, while overexpressed PARP1 did the opposite. PARP1 was the target gene of miR-519a-3p, and it reversed the effects of miR-519a-3p on the migration, invasion, and tube formation of OC cells by upregulating the expressions of PAR, PARP1, N-cadherin, SNAIL, and VEGF and downregulating those of E-cadherin and p53. Conclusion: PARP1, a target gene of miR-519a-3p, promoted the migration, invasion, and tube formation of OC cells, providing a possible therapeutic target for treatment of OC patients.

circHIPK3 regulates proliferation and differentiation of myoblast through the miR-7/TCF12 pathway

Skeletal muscle development is a complex biological process involving multiple key genes, signaling pathways and noncoding RNAs, including microRNAs and circular RNAs (circRNAs). However, the regulatory relationship among them is so complicated that it has not yet been fully elucidated. In this study, we found that miR-7 inhibited C2C12 cell proliferation and differentiation by targeting transcription factor 12 (TCF12). circHIPK3 acted as a competing endogenous RNA, and its overexpression effectively reversed the regulation of miR-7 on C2C12 cell proliferation and differentiation by increasing TCF12 expression. Taken together, our findings provide evidence that circHIPK3 regulates skeletal muscle development through the miR-7/TCF12 pathway. This study provides a scientific basis for further research on skeletal muscle development at the circRNA level.

MicroRNA expression profiles analysis of apheresis platelets treated with vitamin B2 and ultraviolet-B during storage

Whether platelet (PLT) microRNA (miRNA) profiles are affected by pathogen reduction technology (PRT) using vitamin B₂ and ultraviolet-B (VB₂-PRT) remains unclear. Samples from VB₂-PRT-treated (experimental group, E_) and untreated (control group, C_) apheresis PLTs were taken on days 1, 3 and 5 of storage, designated as E_1, E_3, E_5, C_1, C_3 and C_5, respectively. The miRNA expression profiles were assessed by DNA Nano Ball (DNB) sequencing technology, and verified by quantitive real-time fluorescence quantitative PCR (qRT-PCR). Compared with the expression profiles of PLT miRNAs, 3895 miRNAs were identified in the E_ groups while 4106 were in the C_ groups. There were 487 significant differentially expressed miRNAs in E_1 vs C_1 group, including 220 upregulated and 287 downregulated, such as miR-146a-5p and let-7b-5p. There were 908 significant differentially expressed miRNAs in E_3 vs C_3 group, including 297 upregulated and 611 downregulated, such as miR-142-5p and miR-7-5p. There were 229 significant differentially expressed miRNAs in E_5 vs C_5 group, including 80 upregulated and 149 downregulated, such as miR-3529-3p and miR-451a. These differentially expressed miRNAs had been suggested to have functional roles in energy homeostasis, cell communication, proliferation, migration and apoptosis. GO analysis showed a significant enrichmen in relevant biological process categories as receptor activity, signal transduction, cell transport, motility and chemotaxis. The significantly enriched KEGG pathway of predicted target genes was Glycosaminoglycan biosynthesis in E_ vs C_ groups. These new observation could provide insights on the understanding of change of miRNA profiles of PLT treated with VB₂-PRT.

The cross-talk between signaling pathways, noncoding RNAs and DNA damage response: Emerging players in cancer progression

The DNA damage response (DDR) pathway's primary purpose is to maintain the genome structure's integrity and stability. A great deal of effort has done to understand the exact molecular mechanisms of non-coding RNAs, such as lncRNA, miRNAs, and circRNAs, in distinct cellular and genomic processes and cancer progression. In this regard, the ncRNAs possible regulatory role in DDR via modulation of key components expression and controlling repair signaling pathway activation is validated. Therefore, in this article, we will discuss the latest developments of ncRNAs contribution in different aspects of DNA repair through regulation of ATM-ATR, P53, and other regulatory signaling pathways.

MicroRNA-7 modulates cellular senescence to relieve gemcitabine resistance by targeting PARP1/NF-κB signaling in pancreatic cancer cells

Senescence is activated in response to gemcitabine to prevent the propagation of cancer cells. However, there is little evidence on whether senescence is involved in gemcitabine resistance in pancreatic cancer. Increasing evidence has demonstrated that microRNAs (miRs) are potential regulators of cellular senescence. The present study aimed to investigate whether aberrant miR-7 expression modulated senescence to influence pancreatic cancer resistance to chemotherapy. In the present study, cell senescence assay, ALDEFLUOR™ assay, luciferase reporter assay, flow cytometry, quantitative PCR, immunohistochemistry and western blot analysis were performed to explore the association between senescence and gemcitabine therapy response, and to clarify the underlying mechanisms. The present study revealed that gemcitabine-induced chronically existing senescent pancreatic cells possessed stemness markers. Therapy-induced senescence led to gemcitabine resistance. Additionally, it was found that miR-7 expression was decreased in gemcitabine-resistant pancreatic cancer cells, and that miR-7 acted as an important regulator of cellular senescence by targeting poly (ADP-ribose) polymerase 1 (PARP1)/NF-κB signaling. When miR-7 expression was restored, it was able to sensitize pancreatic cancer cells to gemcitabine. In conclusion, the present study demonstrated that miR-7 regulated cellular senescence and relieved gemcitabine resistance by targeting the PARP1/NF-κB axis in pancreatic cancer cells.

Association study of hsa_circ_0001946, hsa-miR-7-5p and PARP1 in coronary atherosclerotic heart disease

BACKGROUND

Our previous work identified an aberrant expression of hsa_circ_0001946 in coronary atherosclerotic heart disease (CHD). Here we aimed to verify the role of hsa_circ_0001946 as a biomarker for CHD, and explore the clues of its downstream regulation.

METHODS

The hsa_circ_0001946 expression in CHD patients (n = 120) and controls (n = 120) were confirmed with qRT-PCR. CircBank and miRDB were used for target analysis in silico. Spearman correlation test was performed to infer potential interrelationships among the nucleic acid molecular biomarkers, and their predictive abilities were examined using receiver operating characteristic (ROC) curves.

RESULTS

Hsa_circ_0001946 was validated to be significantly up-regulated in the peripheral blood mononuclear cells of CHD patients, and revealed as an independent indicator of increased CHD risk (odds ratio: 2.364; 95% confidence interval [CI]: 1.765-3.165) after adjusting for confounding factors. Hsa-miR-7-5p was found to own the largest number of binding sites in has_circ_0001946 sequence, and among its targets predicted, the poly ADP-ribose polymerase 1 (PARP1) has been implicated in the pathophysiology of CHD. Spearman analysis indicated negative correlations of hsa-miR-7-5p with hsa_circ_0001946 and PARP1, respectively; while hsa_circ_0001946 was positively correlated with PARP1. The prediction accuracy of hsa_circ_0001946 in CHD was evaluated, showing an area under the ROC curve of 0.897 (95% CI: 0.791-0.961), which could further increase to 0.957 (95% CI: 0.870-0.992) upon a combination of hsa-miR-7-5p and PARP1.

CONCLUSION

The present work demonstrated the predictive power of hsa_circ_0001946, hsa-miR-7-5p and PARP1 as combined biomarkers for CHD, and suggests a regulatory axis they consisted might contribute to the CHD development.

Combinatory Treatment with miR-7-5p and Drug-Loaded Cubosomes Effectively Impairs Cancer Cells

BACKGROUND

Multidrug resistance (MDR) is an emerging problem in the treatment of cancer. Therefore, there is a necessity for novel strategies that would sensitize tumor cells to the administered chemotherapeutics. One of the innovative approaches in fighting drug-resistant tumors is the treatment of cancer with microRNA (miRNA), or the use of cubosomes (lipid nanoparticles) loaded with drugs. Here, we present a study on a novel approach, which combines both tools.

METHODS

Cubosomes loaded with miR-7-5p and chemotherapeutics were developed. The effects of drug- and miRNA-loaded vehicles on glioma- (A172, T98G), papillary thyroid- (TPC-1) and cervical carcinoma-derived (HeLa) cells were analyzed using molecular biology techniques, including quantitative real-time PCR, MTS-based cell proliferation test, flow cytometry and spheroids formation assay.

RESULTS

The obtained data indicate that miR-7-5p increases the sensitivity of the tested cells to the drug, and that nanoparticles loaded with both miRNA and the drug produce a greater anti-tumor effect in comparison to the free drug treatment. It was found that an increased level of apoptosis in the drug/miRNA co-treated cells is accompanied by an alternation in the expression of the genes encoding for key MDR proteins of the ABC family.

CONCLUSIONS

Overall, co-administration of miR-7-5p with a chemotherapeutic can be considered a promising strategy, leading to reduced MDR and the induction of apoptosis in cancer cells.

Circular RNAs in nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a geographical distributed epithelial tumor of head and neck, which is prevalent in east Africa and Asia, especially southern China. Moreover, NPC has an unfavorable clinical effect and is prone to metastasis at an advanced stage. Although the recovery rate of patients has been improved due to concurrent chemoradiotherapy, poor curative effects and low overall survival remain key issues. The precise mechanisms and pivotal regulators of NPC remain still unclear. To improve the therapeutic efficacy, we focused on related-NPC circular RNAs (circRNAs). CircRNAs are a unique type of endogenous non-coding RNAs (ncRNAs) with a covalent closed-loop structure. Their expression is rich, stable and conservative. Different circRNA have specific tissue and developmental stages and can be detected in body fluids. In addition, circRNAs are involved in multiple pathological processes, especially in cancers. In recent years, using high-throughput indicator technology and bioinformatics technology, a large number of circRNAs have been identified in NPC cells and verified to have biological functions and mechanisms of action. This article aims to provide a retrospective review of the latest research on the proliferation and migration of related-NPC circRNA. Specifically, we focused on the roles and mechanisms of circRNAs in the development and progression of NPC.

CONCLUSION

CircRNA can act as an oncogene or tumor suppressor gene and participate in NPC progression (e.g., proliferation, apoptosis, migration, and invasion). In short, circRNAs have potential as biomarkers for the diagnosis, prognosis and treatment of NPC.

Radiosensitization of Hepatocellular Carcinoma through Targeting Radio-Associated MicroRNA

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related deaths worldwide. For patients who are resistant to monotherapy, multimodal therapy is a basic oncologic principle that incorporates surgery, radiotherapy (RT), and chemotherapy providing survival benefits for patients with most types of cancer. Although liver has low tolerance for radiation, high-precision RT for local HCC minimizes the likelihood of radiation-induced liver disease (RILD) in noncancerous liver tissue. RT have several therapeutic benefits, including the down-staging of tumors to make them resectable and repression of metastasis. The DNA damage response (DDR) is a cellular response to irradiation (IR), including DNA repair of injured cells and induction of programmed cell death, thereby resulting in maintenance of cell homeostasis. Molecules that block the activity of proteins in DDR pathways have been found to enhance radiotherapeutic effects. These molecules include antibodies, kinase inhibitors, siRNAs and miRNAs. MicroRNAs (miRNAs) are short non-coding regulatory RNAs binding to the 3'-untranslated regions (3'-UTR) of the messenger RNAs (mRNAs) of target genes, regulating their translation and expression of proteins. Thus, miRNAs and their target genes constitute complicated interactive networks, which interact with other molecules during carcinogenesis. Due to their promising roles in carcinogenesis, miRNAs were shown to be the potential factors that mediated radiosensitivity and optimized outcomes of the combination of systemic therapy and radiotherapy.

Ischemic postconditioning exerts neuroprotective effect through negatively regulating PI3K/Akt2 signaling pathway by microRNA-124

Ischemic stroke is a serious threat to human life and health, which is often accompanied by cerebral ischemia-reperfusion (I/R) injury in clinic. Ischemic postconditioning (IPostC) is a short period of mild non-fatal ischemia in the early stage of cerebral I/R injury. However, there are few reports about the protective effect of IPostC. In the present study, we investigated the neuroprotective effect of IPostC in a mice model of ischemia induced by the middle cerebral artery occlusion (MCAO). MicroRNA-124(miR-124) is a small RNA highly expressed in the brain. Several studies have shown that miR-124 is significantly decreased in IPostC. Therefore, we hypothesize that IPostC may play an important role by downregulating the expression of miR-124. Mice were treated with cerebral I/R and IPostC treatment on the basis of MCAO. The results showed that IPostC significantly reduced neurobehavioral deficits and decreased brain infarct volume. Moreover, we also found that inhibiting miR-124 effectively reduced neurons/cells apoptosis in vivo and vitro. In addition, western blot analysis of apoptosis-related proteins and PI3K/Akt2 signaling pathway proteins showed that downregulation of miR-124 significantly decreased the expression of Caspase-3 and BAX, and increased the expression of anti-apoptotic protein Bcl-2. Inhibition of miR-124 also increase PI3K/Akt/mTOR signaling pathway, thus inhibiting cell apoptosis and autophagy. However, overexpression of miR-124 weakens the protective effect of IPostC. These observations suggest that IPostC exerts its neuroprotective effect through negatively regulating PI3K/Akt2 signaling pathway by miR-124.

Plasma MicroRNA Expression Profiles in Psoriasis

Background

Psoriasis is an immune-mediated inflammatory chronic skin disease characterized by chronic inflammation in the dermis, parakeratosis, and excessive epidermal growth. MicroRNAs (miRNAs) are key regulators of immune responses. Although differential expression of miRNAs has been reported in certain inflammatory autoimmune diseases, their role in psoriasis has not been fully illuminated. Our aims were to confirm plasma miRNA expression signatures in psoriasis and to examine their potential influence on psoriasis pathogenesis.

Methods

A miRNome PCR array was used to analyse the plasma of psoriasis patients and healthy donors. We performed miRNA pathway enrichment and target gene network analyses on psoriasis plasma samples.

Results

We found several specific plasma miRNA signatures relevant to psoriasis. The miRNAs targeted pathways associated with psoriasis, such as the VEGF, MAPK, and WNT signaling pathways. Network analysis revealed pivotal deregulated plasma miRNAs and their relevant target genes and pathways regulating psoriasis pathogenesis.

Conclusions

This study analysed the expression of plasma miRNAs and their target pathways, elucidating the pathogenesis of psoriasis; these results may be used to design novel therapeutic strategies and to identify diagnostic biomarkers for psoriasis.

Inhibition of CRY2 by STAT3/miRNA-7-5p Promotes Osteoblast Differentiation through Upregulation of CLOCK/BMAL1/P300 Expression

Accumulating evidence indicates that cryptochrome circadian regulatory (CRY) proteins have emerged as crucial regulators of osteogenic differentiation. However, the associated mechanisms are quite elusive. In this study, we show that knockdown of CRY2 downregulated the expression of runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), osteocalcin (OCN), and osteopontin (OPN) to facilitate osteoblast differentiation. Further study identified that CRY2 was directly targeted by microRNA (miR)-7-5p, which was highly induced during osteoblast differentiation. The expression of Runx2, ALP, collagen type I alpha 1 (Col1a1), and OCN was upregulated by overexpression of miR-7-5p and induction of osteoblast differentiation. Moreover, signal transducer and activator of transcription 3 (STAT3) transcriptionally activated miR-7-5p to significantly enhance the expression of above osteogenic marker genes and mineral formation. However, overexpression of CRY2 abolished the osteogenic differentiation induced by miR-7-5p overexpression. Silencing of CRY2 unraveled the binding of CRY2 with the circadian locomotor output cycles kaput (CLOCK)/brain and muscle ARNT-like 1 (BMAL1) complex to release CLOCK/BMAL1, which facilitated the binding of CLOCK/BMAL1 to the promoter region of the P300 E-box to stimulate the transcription of P300. P300 subsequently promoted the acetylation of histone 3 and the formation of a transcriptional complex with Runx2 to enhance osteogenesis. Taken together, our study revealed that CRY2 is repressed by STAT3/miR-7-5p to promote osteogenic differentiation through CLOCK/BMAL1/P300 signaling. The involved molecules may be potentially targeted for treatment of osteoporosis.

Circular RNA CDR1as sponges miR-7-5p to enhance E2F3 stability and promote the growth of nasopharyngeal carcinoma

Background

Circular RNA (circRNA) CDR1as plays an important role in the occurrence and development of human tumors. The purpose of this study is to investigate the molecular mechanism of circRNA CDR1as in the development of nasopharyngeal carcinoma (NPC).

Methods

The mRNA expressions of circRNA CDR1as, miR-7-5p, and E2F3 were detected by qRT-PCR. The effects of circRNA CDR1as, miR-7-5p, and E2F3 on NPC cells were investigated using cell counting kit-8 (CCK8) method, colony formation assay, and representative metabolite assay. The molecular mechanism of circRNA CDR1 in NPC was studied by bioinformatics and luciferase reporter assay. In addition, the biological activity of circRNA CDR1as was also investigated in NPC xenograft tumor mice model.

Results

The results showed that the circRNA CDR1as expression was significantly up-regulated in NPC tissues by comparison with non-tumor NPE tissues (p < 0.01), suggesting that circRNA CDR1as was associated with poor prognosis in NPC patients. Moreover, circRNA CDR1as could up-regulate E2F3 expression by binding miR-7-5p, and promote the growth and glucose metabolism of NPC cells. Meanwhile, circRNA CDR1as could promote NPC progression through the negative regulation of miR-7-5p in the xenograft tumor model.

Conclusion

CircRNA CDR1as promoted the occurrence and development of NPCs by successively up-regulating the expression of miR-7-5p and E2F3, suggesting CircRNA CDR1as as a potential target for the treatment of NPC patients.

Trial registration The study was approved by the cancer center’s institutional research ethics committee on Oct 18, 2008 (2008GZ2847462)

Exosomal miR-221 derived from hydroquinone-transformed malignant human bronchial epithelial cells is involved in cell viability of recipient cells

miR-221, an oncogenic microRNA, can promote cell proliferation and is highly expressed in various types of tumors. However, the role of exosomal miR-221 in benzene-caused carcinogenesis remains elusive. Our study was designed to investigate whether exosomes secreted by the hydroquinone (HQ; an active metabolite of benzene)-transformed malignant cells can transmit miR-221 to normal recipient cells and its possible effects on cell viability. Our investigation revealed that expression levels of miR-221 were significantly increased in HQ-transformed malignant cells relative to normal controls. Furthermore, exposure of control cells to exosomes that were derived from HQ-transformed malignant cells increased miR-221 levels and promoted their proliferation. Analyses of the biological potency of exosomes derived from HQ-transformed malignant cells in which miR-221 levels were decreased using an inhibitor, showed that both miR-221 levels and proliferation of recipient cells were decreased, but still were higher than those of normal 16HBE cells. Our study indicates that exosomal miR-221 derived from HQ-transformed malignant human bronchial epithelial cells is involved in the proliferation of recipient cells.

MiR-7-5p-mediated downregulation of PARP1 impacts DNA homologous recombination repair and resistance to doxorubicin in small cell lung cancer

Background

Chemo-resistance is one of the major challenges in the therapy of small cell lung cancer (SCLC). Multiple mechanisms are thought to be involved in chemo-resistance during SCLC treatment, but unfortunately, these mechanisms have not been well elucidated. Herein, we investigated the role of miRNA in the resistance of SCLC cells to doxorubicin (Dox).

Methods

MiRNA microarray analysis revealed that several miRNAs, including miR-7-5p, were specifically decreased in Dox-resistant SCLC cells (H69AR) compared to parental cells (H69). The expression level of miR-7-5p was confirmed by qRT-PCR in Dox-resistant cells (H69AR and H446AR cells) and their parental cells. Bioinformatic analysis indicated that poly ADP-ribose polymerase 1 (PARP1) is a direct target of miR-7-5p. The binding sites of miR-7-5p in the PARP1 3′ UTR were verified by luciferase reporter and Western blot assays. To investigate the role of miR-7-5p in the chemo-resistance of SCLC cells to doxorubicin, mimic or inhibitor of miR-7-5p was transfected into SCLC cells, and the effect of miR-7-5p on homologous recombination (HR) repair was analyzed by HR reporter assays. Furthermore, the expression of HR repair factors (Rad51 and BRCA1) induced by doxorubicin was detected by Western blot and immunofluorescent staining in H446AR cells transfected with miR-7-5p mimic.

Results

The expression level of miR-7-5p was remarkably reduced (4-fold) in Dox-resistant SCLC cells (H69AR and H446AR cells) compared with that in parental cells (H69 and H446 cells). Poly ADP-ribose polymerase 1 (PARP1) is a direct target of miR-7-5p, and PARP1 expression was downregulated by miR-7-5p. MiR-7-5p impeded Dox-induced HR repair by inhibiting the expression of HR repair factors (Rad51 and BRCA1) that resulted in resensitizing SCLC cells to doxorubicin.

Conclusions

Our findings provide evidence that miR-7-5p targets PARP1 to exert its suppressive effects on HR repair, indicating that the alteration of the expression of miR-7-5p may be a promising strategy for overcoming chemo-resistance in SCLC therapy.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5798-7) contains supplementary material, which is available to authorized users.

Benzene metabolite hydroquinone promotes DNA homologous recombination repair via the NF-κB pathway

Benzene, a widespread environmental pollutant, induces DNA double-strand breaks (DSBs) and DNA repair, which may further lead to oncogenic mutations, chromosomal rearrangements and leukemogenesis. However, the molecular mechanisms underlying benzene-induced DNA repair and carcinogenesis remain unclear. The human osteosarcoma cell line (U2OS/DR-GFP), which carries a GFP-based homologous recombination (HR) repair reporter, was treated with hydroquinone, one of the major benzene metabolites, to identify the potential effects of benzene on DSB HR repair. RNA-sequencing was further employed to identify the potential key pathway that contributed to benzene-initiated HR repair. We found that treatment with hydroquinone induced a significant increase in HR. NF-κB pathway, which plays a critical role in carcinogenesis in multiple tumors, was significantly activated in cells recovered from hydroquinone treatment. Furthermore, the upregulation of NF-κB by hydroquinone was also found in human hematopoietic stem and progenitor cells. Notably, the inhibition of NF-κB activity by small molecule inhibitors (QNZ and JSH-23) significantly reduced the frequency of hydroquinone-initiated HR (−1.36- and −1.77-fold, respectively, P < 0.01). Our results demonstrate an important role of NF-κB activity in promoting HR repair induced by hydroquinone. This finding sheds light on the underlying mechanisms involved in benzene-induced genomic instability and leukemogenesis and may contribute to the larger exploration of the influence of other environmental pollutants on carcinogenesis.