Transactivation of miR-34a by p53 broadly influences gene expression and promotes apoptosis

Micromanaging pattern formation: miRNA regulation of signaling systems in vertebrate development

Early embryogenesis requires the establishment of fields of progenitor cells with distinct molecular signatures. A balance of intrinsic and extrinsic cues determines the boundaries of embryonic territories and pushes progenitor cells toward different fates. This process involves multiple layers of regulation, including signaling systems, transcriptional networks, and post-transcriptional control. In recent years, microRNAs (miRNAs) have emerged as undisputed regulators of developmental processes. Here, we discuss how miRNAs regulate pattern formation during vertebrate embryogenesis. We survey how miRNAs modulate the activity of signaling pathways to optimize transcriptional responses in embryonic cells. We also examine how localized RNA interference can generate spatial complexity during early development. Unraveling the complex crosstalk between miRNAs, signaling systems and cell fate decisions will be crucial for our understanding of developmental outcomes and disease.

Reduction of lithium induced interstitial fibrosis on co-administration with amiloride

Long-term administration of lithium is associated with chronic interstitial fibrosis that is partially reduced with exposure to amiloride. We examined potential pathways of how amiloride may reduce interstitial fibrosis. Amiloride was administered to a rat model of lithium induced interstitial fibrosis over a long term (6 months), as well as for short terms of 14 and 28 days. Kidney cortical tissue was subjected to RNA sequencing and microRNA expression analysis. Gene expression changes of interest were confirmed using immunohistochemistry on kidney tissue. Pathways identified by RNA sequencing of kidney tissue were related to 'promoting inflammation' for lithium and 'reducing inflammation' for amiloride. Validation of candidate genes found amiloride reduced inflammatory components induced by lithium including NF-κB/p65^Ser536 and activated pAKT^Ser473, and increased p53 mediated regulatory function through increased p21 in damaged tubular epithelial cells. Amiloride also reduced the amount of Notch1 positive PDGFrβ pericytes and infiltrating CD3 cells in the interstitium. Thus, amiloride attenuates a multitude of pro-inflammatory components induced by lithium. This suggests amiloride could be repurposed as a possible anti-inflammatory, anti-fibrotic agent to prevent or reduce the development of chronic interstitial fibrosis.

Panoramic view of microRNAs in regulating cancer stem cells

Cancer stem cells (CSCs) are a subgroup of tumor cells, possessing the abilities of self-renewal and generation of heterogeneous tumor cell lineages. They are believed to be responsible for tumor initiation, metastasis, as well as chemoresistance in human malignancies. MicroRNAs (miRNAs) are small noncoding RNAs that play essential roles in various cellular activities including CSC initiation and CSC-related properties. Mature miRNAs with ∼22 nucleotides in length are generated from primary miRNAs via its precursors by miRNA-processing machinery. Extensive studies have demonstrated that mature miRNAs modulate CSC initiation and stemness features by regulating multiple pathways and targeting stemness-related factors. Meanwhile, both miRNA precursors and miRNA-processing machinery can also affect CSC properties, unveiling a new insight into miRNA function. The present review summarizes the roles of mature miRNAs, miRNA precursors, and miRNA-processing machinery in regulating CSC properties with a specific focus on the related molecular mechanisms, and also outlines the potential application of miRNAs in cancer diagnosis, predicting prognosis, as well as clinical therapy.

Comprehensive analysis of differentially expressed profiles of mRNA, lncRNA, and miRNA of Yili geese ovary at different egg-laying stages

Background

The development of the ovaries is an important factor that affects egg production performance in geese. Ovarian development is regulated by genes that are expressed dynamically and stage-specifically. The transcriptome profile analysis on ovarian tissues of goose at different egg laying stages could provide an important basis for screening and identifying key genes regulating ovarian development.

Results

In this study, 4 ovary tissues at each breeding period of pre-laying (PP), laying (LP), and ceased-laying period (CP), respectively, with significant morphology difference, were used for RNA extraction and mRNAs, lncRNAs, and miRNAs comparison in Yili geese. CeRNA regulatory network was constructed for key genes screening. A total of 337, 1136, and 525 differentially expressed DE mRNAs, 466, 925, and 742 DE lncRNAs and 258, 1131 and 909 DE miRNAs were identified between PP and LP, between CP and LP, and between CP and PP groups, respectively. Functional enrichment analysis showed that the differentially expressed mRNAs and non-coding RNA target genes were mainly involved in the cell process, cytokine-cytokine receptor interaction, phagosome, calcium signaling pathway, steroid biosynthesis and ECM-receptor interaction. Differential genes and non-coding RNAs, PDGFRB, ERBB4, LHCGR, MSTRG.129094.34, MSTRG.3524.1 and gga-miR-145–5p, related to reproduction and ovarian development were highly enriched. Furthermore, lncRNA-miRNA-mRNA regulatory networks related to ovary development were constructed.

Conclusions

Our study found dramatic transcriptomic differences in ovaries of Yili geese at different egg-laying stages, and a differential lncRNA-miRNA-mRNA regulatory network related to cell proliferation, differentiation and apoptosis and involved in stromal follicle development were established and preliminarily validated, which could be regarded as a key regulatory pathway of ovarian development in Yili geese.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08774-4.

A miR-34a-guided, tRNAiMet-derived, piR_019752-like fragment (tRiMetF31) suppresses migration and angiogenesis of breast cancer cells via targeting PFKFB3

Although we recently demonstrated that miR-34a directly targets tRNA_i^Met precursors via Argonaute 2 (AGO2)-mediated cleavage, consequently attenuating the proliferation of breast cancer cells, whether tRNA_i^Met fragments derived from this cleavage influence breast tumor angiogenesis remains unknown. Here, using small-RNA-Seq, we identified a tRNA_i^Met-derived, piR_019752-like 31-nt fragment tRiMetF31 in breast cancer cells expressing miR-34a. Bioinformatic analysis predicted 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) as a potential target of tRiMrtF31, which was validated by luciferase assay. tRiMetF31 was downregulated, whereas PFKFB3 was overexpressed in cancer cell lines. Overexpression of tRiMetF31 profoundly inhibited the migration and angiogenesis of two breast cancer cell lines while slightly inducing apoptosis. Conversely, knockdown of tRiMetF31 restored PFKFB3-driven angiogenesis. miR-34a was downregulated, whereas tRNA_i^Met and PFKFB3 were upregulated in breast cancer, and elevated PFKFB3 significantly correlated with metastasis. Our findings demonstrate that tRiMetF31 profoundly suppresses angiogenesis by silencing PFKFB3, presenting a novel target for therapeutic intervention in breast cancer.

The role of miR-4469 as a tumor suppressor regulating inflammatory cell infiltration in colorectal cancer

Background

MicroRNA (miRNA) regulates gene expression posttranscriptionally, and some of them function in tumor suppression and can be used in drug development. As a result, identifying and screening miRNAs that suppress tumors would be a significant addition to tumor treatment.

Methods

In this study, we analyzed the miRNA expression profile of colorectal cancer (CRC), constructed a negative regulatory network of the miRNA-target genes, and identified miR-4469 as one of the key tumor suppressors miRNAs. We analyzed the expression and survival of miR-4469 in pan-cancer, experimentally verified the expression level of miR-4469 in CRC cells and the effect on CRC cell proliferation and migration. We screened miR-4469 target genes for enrichment analysis and immune cell infiltration analysis and validated target gene expression to clarify the regulatory mechanisms involved in miR-4469.

Results

miR-4469 was more highly expressed in normal colorectum tissues compared to CRC tissues and correlated with survival time in patients with multiple cancers. It was shown that miR-4469 was highly expressed in normal colon cells and miR-4469 expression could inhibit the proliferation and migration of CRC cells. In addition, studies on the mechanism showed that miR-4469 function is mainly related to the regulation of inflammatory cell infiltration, and the key target genes of miR-4469 in this process are SLC2A3, FGR, PLEKHO2, and MYO1F.

Conclusion

miR-4469 is a tumor suppressor in CRC, and its regulatory mechanism mainly affects the infiltration of inflammatory cells in the cancer tissue.

Promising Biomarkers in Head and Neck Cancer: The Most Clinically Important miRNAs

Head and neck cancers (HNCs) comprise a heterogeneous group of tumors that extend from the oral cavity to the upper gastrointestinal tract. The principal etiologic factors for oral tumors include tobacco smoking and alcohol consumption, while human papillomavirus (HPV) infections have been accused of a high incidence of pharyngeal tumors. Accordingly, HPV detection has been extensively used to categorize carcinomas of the head and neck. The diverse nature of HNC highlights the necessity for novel, sensitive, and precise biomarkers for the prompt diagnosis of the disease, its successful monitoring, and the timely prognosis of patient clinical outcomes. In this context, the identification of certain microRNAs (miRNAs) and/or the detection of alterations in their expression patterns, in a variety of somatic fluids and tissues, could serve as valuable biomarkers for precision oncology. In the present review, we summarize some of the most frequently studied miRNAs (including miR-21, -375, -99, -34a, -200, -31, -125a/b, -196a/b, -9, -181a, -155, -146a, -23a, -16, -29, and let-7), their role as biomarkers, and their implication in HNC pathogenesis. Moreover, we designate the potential of given miRNAs and miRNA signatures as novel diagnostic and prognostic tools for successful patient stratification. Finally, we discuss the currently ongoing clinical trials that aim to identify the diagnostic, prognostic, or therapeutic utility of miRNAs in HNC.

The Role of Ferroptosis in Acute Kidney Injury

Ferroptosis is a novel cell death method discovered in recent years. It is usually accompanied by massive accumulations of iron and lipid peroxidation during cell death. Recent studies have shown that ferroptosis is closely associated with the pathophysiological processes of many diseases, such as tumors, neurological diseases, localized ischemia-reperfusion injury, kidney injury, and hematological diseases. How to intervene in the incidence and development of associated diseases by regulating the ferroptosis of cells has become a hot topic of research. This article provides a review of the role of ferroptosis in the pathogenesis and potential treatment of acute kidney injury.

MicroRNAs influence and longevity

Background

MiRNAs play critical roles in the regulation of cellular function, life span, and the aging process. They can affect longevity positively and negatively through different aging pathways.

Main text

MiRNAs are a group of short non-coding RNAs that regulate gene expressions at post-transcriptional levels. The different types of alterations in miRNAs biogenesis, mRNA expressions, and activities of miRNA-protein complexes can affect the regulation of normal post-transcriptional gene process, which may lead to aging, age-related diseases, and an earlier death. It seems that the influence of deregulation of miRNAs on senescence and age-related diseases occurring by targeting aging molecular pathways can be used for diagnosis and prognosis of them. Therefore, the expression and function of miRNAs should be studied more accurately with new applicable and validated experimental tools. However, the current review wishes to highlight simply a connection among miRNAs, senescence and some age-related diseases.

Conclusion

Despite several research indicating the key roles of miRNAs in aging and longevity, further investigations are still needed to elucidate the essential roles of miRNAs in controlling mRNA regulation, cell proliferation, death and/or protection during stress and health problems. Besides, more research on miRNAs will help to identify new targets for alternative strategies regarding effectively screen, treat, and prevent diseases as well as make slow the aging process.

miR-34a predicts the prognosis of advanced-stage external auditory canal squamous cell carcinoma

BACKGROUND

External auditory canal (EAC) squamous cell carcinoma (SCC) is a rare disease, and the survival rate is low in the advanced stages. It has been reported that miR-34a expression is low in many cancers and acts as a tumor suppressor, but its function in EACSCC has not yet been reported.

AIMS

To analyze the miR-34a expression levels in EACSCC specimens using in situ hybridization (ISH).

MATERIAL AND METHODS

We performed microRNA ISH for miR-34a detection and immunohistochemical analysis of p53 and Ki67 in the EACSCC and otitis externa (OE) specimens.

RESULTS

miR-34a was expressed in the basal and suprabasal layers in the OE epidermis. The pronounced expression of miR-34a was observed in the two cases of T2 (Stage II). In the one case of T3 (Stage III), it was almost the same as that of the OE. On the other hand, the expression levels of miR-34a in the one case of T3 (Stage IV) and two cases of T4 (Stage IV) were apparently reduced.

CONCLUSION

We demonstrated that the expression level of miR-34a was higher in early-stage EACSCC and lower in advanced-stage EACSCC.

SIGNIFICANCE

The expression level of miR-34a may predict a prognosis in patients with advanced-stage EACSCC.

Potential role of microRNAs in pancreatic cancer manifestation: a review

Cancer cells are different from normal cells in regard to phenotypic and functional expression. Cancer is the outcome of aberrant gene expression affecting various cellular signaling pathways. MicroRNAs (MiRs) are small, non-coding RNAs regulating the expression of various protein-coding genes post-transcriptionally and are known to play critical roles in the complicated cellular pathways leading to cell growth, proliferation, development, and apoptosis. MiRs are involved in various cancer-related pathways and function both as tumor suppressor and cancer-causing genes. There is a need for significant biomarkers, and better prognostication of response to a particular treatment and liquid biopsy could be useful to appraise such potential biomarkers. This review has focused on the involvement of anomalous expression of miRs in human pancreatic cancer and the investigation of miR-based biomarkers for disease diagnosis and better therapeutic selection.

Pancreatic Cancer: Nucleic Acid Drug Discovery and Targeted Therapy

Pancreatic cancer (PC) is one of the most lethal cancers with an almost 10% 5-year survival rate. Because PC is implicated in high heterogeneity, desmoplastic tumor-microenvironment, and inefficient drug-penetration, the chemotherapeutic strategy currently recommended for the treatment of PC has limited clinical benefit. Nucleic acid-based targeting therapies have become strong competitors in the realm of drug discovery and targeted therapy. A vast evidence has demonstrated that antibody-based or alternatively aptamer-based strategy largely contributed to the elevated drug accumulation in tumors with reduced systematic cytotoxicity. This review describes the advanced progress of antisense oligonucleotides (ASOs), small interfering RNAs (siRNAs), microRNAs (miRNAs), messenger RNA (mRNAs), and aptamer-drug conjugates (ApDCs) in the treatment of PC, revealing the bright application and development direction in PC therapy.

Multi-omics analysis revealed TEK and AXIN2 are potential biomarkers in multifocal papillary thyroid cancer

BACKGROUND

Papillary thyroid carcinoma (PTC), the most common endocrine cancer, accounts for 80-85% of all malignant thyroid tumors. This study focused on identifying targets that affect the multifocality of PTC. In a previous study, we determined 158 mRNAs related to multifocality in BRAF-mutated PTC using The Cancer Genome Atlas.

METHODS

We used multi-omics data (miRNAs and mRNAs) to identify the regulatory mechanisms of the investigated mRNAs. miRNA inhibitors were used to determine the relationship between mRNAs and miRNAs. We analyzed the target protein levels in patient sera using ELISA and immunohistochemical staining of patients' tissues.

RESULTS

We identified 44 miRNAs that showed a negative correlation with mRNA expression. Using in vitro experiments, we identified four miRNAs that inhibit TEK and/or AXIN2 among the target mRNAs. We also showed that the downregulation of TEK and AXIN2 decreased the proliferation and migration of BRAF ( +) PTC cells. To evaluate the diagnostic ability of multifocal PTC, we examined serum TEK or AXIN2 in unifocal and multifocal PTC patients using ELISA, and showed that the serum TEK in multifocal PTC patients was higher than that in the unifocal PTC patients. The immunohistochemical study showed higher TEK and AXIN2 expression in multifocal PTC than unifocal PTC.

CONCLUSIONS

Both TEK and AXIN2 play a potential role in the multifocality of PTC, and serum TEK may be a diagnostic marker for multifocal PTC.

A rationalized definition of general tumor suppressor microRNAs excludes miR-34a

While several microRNAs (miRNAs) have been proposed to act as tumor suppressors, a consensual definition of tumor suppressing miRNAs is still missing. Similarly to coding genes, we propose that tumor suppressor miRNAs must show evidence of genetic or epigenetic inactivation in cancers, and exhibit an anti-tumorigenic (e.g., anti-proliferative) activity under endogenous expression levels. Here we observe that this definition excludes the most extensively studied tumor suppressor candidate miRNA, miR-34a. In analyzable cancer types, miR-34a does not appear to be down-regulated in primary tumors relatively to normal adjacent tissues. Deletion of miR-34a is occasionally found in human cancers, but it does not seem to be driven by an anti-tumorigenic activity of the miRNA, since it is not observed upon smaller, miR-34a-specific alterations. Its anti-proliferative action was observed upon large, supra-physiological transfection of synthetic miR-34a in cultured cells, and our data indicates that endogenous miR-34a levels do not have such an effect. Our results therefore argue against a general tumor suppressive function for miR-34a, providing an explanation to the lack of efficiency of synthetic miR-34a administration against solid tumors.

Up-regulation of microRNA-34a mediates ethanol-induced impairment of neural crest cell migration in vitro and in zebrafish embryos through modulating epithelial-mesenchymal transition by targeting Snail1

Prenatal ethanol exposure can impair neural crest cell (NCC) development, including NCC survival, differentiation and migration, contributing to the craniofacial dysmorphology in Fetal Alcohol Spectrum Disorders (FASD). Epithelial-mesenchymal transition (EMT) plays an important role in regulating the migration of NCCs. The objective of this study is to determine whether ethanol exposure can suppress NCC migration through inhibiting EMT and whether microRNA-34a (miR-34a) is involved in the ethanol-induced impairment of EMT in NCCs. We found that exposure to 100 mM ethanol significantly inhibited the migration of NCCs. qRT-PCR and Western Blot analysis revealed that exposure to ethanol robustly reduced the mRNA and protein expression of Snail1, a critical transcriptional factor that has a pivotal role in the regulation of EMT. Ethanol exposure also significantly increased the mRNA expression of the Snail1 target gene E-cadherin1 and inhibited EMT in NCCs. We also found that exposure to ethanol significantly elevated the expression of miR-34a that targets Snail1 in NCCs. In addition, down-regulation of miR-34a prevented ethanol-induced repression of Snail1 and diminished ethanol-induced upregulation of Snail1 target gene E-cadherin1 in NCCs. Inhibition of miR-34a restored EMT and prevented ethanol-induced inhibition of NCC migration in vitro and in zebrafish embryos in vivo. These results demonstrate that ethanol-induced upregulation of miR-34a contributes to the impairment of NCC migration through suppressing EMT by targeting Snail1.

MicroRNA-1246 suppresses the metastasis of breast cancer cells by targeting the DYRK1A/PGRN axis to prevent the epithelial-mesenchymal transition

OBJECTIVE

Breast cancer is one of the most common malignant and highly heterogeneous tumors in women. MicroRNAs (miRNAs), such as miR-1246, play important roles in various types of malignant cancers, including triple-negative breast cancer (TNBC). However, the biological role of miR-1246 in TNBC has not yet been fully elucidated. In this study, we studied the role of miR-1246 in the occurrence and development of TNBC and its mechanism of action.

METHODS

Cell Counting Kit-8 (CCK-8), wound healing, and Transwell assays were performed to observe the effects of miR-1246 on TNBC cell proliferation, migration, and invasion, respectively. The expression of epithelial-mesenchymal transition (EMT) markers was detected by western blotting. Dual luciferase reporter assays were performed to determine whether DYRK1A is a novel target of miR-1246. In addition, an immunoprecipitation experiment was performed to verify the binding of DYRK1A to PGRN. Rescue experiments were performed to determine whether DYRK1A is a novel target of miR-1246 and whether miR-1246 suppresses the metastasis of breast cancer cells by targeting the DYRK1A/PGRN axis to prevent the epithelial-mesenchymal transition.

RESULTS

Our results show that miR‑1246 suppresses the proliferation, migration, and invasion of TNBC cells, DYRK1A is a novel target of miR-1246 and Importin-8 mediated miR-1246 nuclear translocation. MiR‑1246 plays a suppressive role in the regulation of the EMT of TNBC cells by targeting DYRK1A. DYRK1A mediates the metastasis of triple-negative breast cancer via activation of the EMT. We identified PGRN as a novel DYRK1A-interacting protein. Overexpression of PGRN and DYRK1A promoted cell proliferation and migration of TNBC, but this effect was reversed by co-expression of miR-1246 mimics.DYRK1A and PGRN act together to regulate the occurrence and development of breast cancer through miR-1246.

CONCLUSION

MiR-1246 suppresses the metastasis of breast cancer cells by targeting the DYRK1A/PGRN axis and preventing the epithelial-mesenchymal transition. The MiR-1246/DYRK1A/PGRN axis regulates TNBC progression, suggesting that MiR-1246 could be promising therapeutic targets for the treatment of TNBC.

Evaluation of Expressed MicroRNAs as Prospective Biomarkers for Detection of Breast Cancer

Background: Early detection and screening of breast cancer (BC) might help improve the prognosis of BC patients. This study evaluated the use of serum microRNAs (miRs) as non-invasive biomarkers in BC patients. Methods: Using quantitative real-time polymerase chain reaction, we evaluated the serum expression of four candidate miRs (miR-155, miR-373, miR-10b, and miR-34a) in 99 Egyptian BC patients and 40 healthy subjects (as a control). The miRs expression was correlated with clinicopathological data. In addition, the sensitivity and specificity of the miRs were determined using receiver operating characteristic (ROC) curve analysis. Results: Serum miR-155, miR-373, and miR-10b expression were significantly upregulated (p < 0.001), while serum miR-34a was downregulated (p < 0.00) in nonmetastatic (M0) BC patients compared to the control group. In addition, serum miR-155 and miR-10b were upregulated in BC patients with large tumor sizes and extensive nodal involvement (p < 0.001). ROC curve analysis showed high diagnostic accuracy (area under the curve = 1.0) when the four miRs were combined. Serum miR-373 was significantly upregulated in the human epidermal growth factor 2−negative (p < 0.001), estrogen receptor−positive (p < 0.005), and progesterone receptor (PR)-positive (p < 0.024) in BC patients, and serum miR-155 was significantly upregulated in PR-negative (p < 0.001) BC patients while both serum miR-155 and miR-373 were positively correlated with the tumor grade. Conclusions: Circulating serum miR-155, miR-373, miR-10b, and miR-34a are potential biomarkers for early BC detection in Egyptian patients and their combination shows high sensitivity and specificity.

Role of miRNAs in Neurodegeneration: From Disease Cause to Tools of Biomarker Discovery and Therapeutics

Neurodegenerative diseases originate from neuronal loss in the central nervous system (CNS). These debilitating diseases progress with age and have become common due to an increase in longevity. The National Institute of Environmental Health Science’s 2021 annual report suggests around 6.2 million Americans are living with Alzheimer’s disease, and there is a possibility that there will be 1.2 million Parkinson’s disease patients in the USA by 2030. There is no clear-cut universal mechanism for identifying neurodegenerative diseases, and therefore, they pose a challenge for neurobiology scientists. Genetic and environmental factors modulate these diseases leading to familial or sporadic forms. Prior studies have shown that miRNA levels are altered during the course of the disease, thereby suggesting that these noncoding RNAs may be the contributing factor in neurodegeneration. In this review, we highlight the role of miRNAs in the pathogenesis of neurodegenerative diseases. Through this review, we aim to achieve four main objectives: First, we highlight how dysregulation of miRNA biogenesis led to these diseases. Second, we highlight the computational or bioinformatics tools required to identify the putative molecular targets of miRNAs, leading to biological molecular pathways or mechanisms involved in these diseases. Third, we focus on the dysregulation of miRNAs and their target genes leading to several neurodegenerative diseases. In the final section, we highlight the use of miRNAs as potential diagnostic biomarkers in the early asymptomatic preclinical diagnosis of these age-dependent debilitating diseases. Additionally, we discuss the challenges and advances in the development of miRNA therapeutics for brain targeting. We list some of the innovative strategies employed to deliver miRNA into target cells and the relevance of these viral and non-viral carrier systems in RNA therapy for neurodegenerative diseases. In summary, this review highlights the relevance of studying brain-enriched miRNAs, the mechanisms underlying their regulation of target gene expression, their dysregulation leading to progressive neurodegeneration, and their potential for biomarker marker and therapeutic intervention. This review thereby highlights ways for the effective diagnosis and prevention of these neurodegenerative disorders in the near future.

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

Cardiotoxicity is a serious adverse effect of an anticancer drug, doxorubicin (DOX), which can occur within a year or decades after completion of therapy. The present study was designed to address a knowledge gap concerning a lack of circulating biomarkers capable of predicting the risk of cardiotoxicity induced by DOX. Profiling of 2083 microRNAs (miRNAs) in mouse plasma revealed 81 differentially expressed miRNAs one week after 6, 9, 12, 18, or 24 mg/kg total cumulative DOX doses (early-onset model) or saline (SAL). Among these, the expression of 7 miRNAs were altered prior to the onset of myocardial injury at 12 mg/kg and higher cumulative doses. The expression of only miR-34a-5p was significantly (FDR<0.1) elevated at all total cumulative doses compared to concurrent SAL-treated controls and showed a statistically significant dose-related response. The trend in plasma miR-34a-5p expression levels during DOX exposures also correlated with a significant dose-related increase in cardiac expression of miR-34a-5p in these mice. Administration of a cardioprotective drug, dexrazoxane, to mice before DOX treatment, significantly mitigated miR-34a-5p expression in both plasma and heart in conjunction with attenuation of cardiac pathology. This association between plasma and heart may suggest miR-34a-5p as a potential early circulating marker of early-onset DOX cardiotoxicity. In addition, higher expression of miR-34a-5p (FDR<0.1) in plasma and heart compared to SAL-treated controls 24 weeks after 24 mg/kg total cumulative DOX dose, when cardiac function was altered in our recently established delayed-onset cardiotoxicity model, indicated its potential as an early biomarker of delayed-onset cardiotoxicity.

A review of the biological role of miRNAs in prostate cancer suppression and progression

Prostate cancer (PC) is the third-leading cause of cancer-related deaths worldwide. Although the current treatment strategies are progressing rapidly, PC is still representing a substantial medical problem for affected patients. Several factors are involved in PC initiation, progression, and treatments failure including microRNAs (miRNAs). The miRNAs are endogenous short non-coding RNA sequence negatively regulating target mRNA expression via degradation or translation repression. miRNAs play a pivotal role in PC pathogenesis through its ability to initiate the induction of cancer stem cells (CSCs) and proliferation, as well as sustained cell cycle, evading apoptosis, invasion, angiogenesis, and metastasis. Furthermore, miRNAs regulate major molecular pathways affecting PC such as the androgen receptor (AR) pathway, p53 pathway, PTEN/PI3K/AKT pathway, and Wnt/β-catenin pathway. Furthermore, miRNAs alter PC therapeutic response towards the androgen deprivation therapy (ADT), chemotherapy and radiation therapy (RT). Thus, the understanding and profiling of the altered miRNAs expression in PC could be utilized as a non-invasive biomarker for the early diagnosis as well as for patient sub-grouping with different prognoses for individualized treatment. Accordingly, in the current review, we summarized in updated form the roles of various oncogenic and tumor suppressor (TS) miRNAs in PC, revealing their underlying molecular mechanisms in PC initiation and progression.

p53 in ferroptosis regulation: the new weapon for the old guardian

Although the conventional activities of p53 such as cell cycle arrest, senescence, and apoptosis are well accepted as the major checkpoints in stress responses, accumulating evidence implicates the importance of other tumor suppression mechanisms. Among these unconventional activities, an iron-dependent form of non-apoptotic cell death, termed ferroptosis, attracts great interest. Unlike apoptotic cell death, activation of p53 alone is not sufficient to induce ferroptosis directly; instead, through its metabolic targets, p53 is able to modulate the ferroptosis response in the presence of ferroptosis inducers such as GPX4 inhibitors or high levels of ROS. Here, we review the role of ferroptosis in p53-mediated tumor suppression, with a focus on what cellular factors are critical for p53-dependent ferroptosis during tumor suppression and how p53 modulates both the canonical (GPX4-dependent) and the non-canonical (GPX4-independent) ferroptosis pathways. We also discuss the possibility of targeting p53-mediated ferroptotic responses for the treatment of human cancers and potentially, other diseases.

HELLS Is Negatively Regulated by Wild-Type P53 in Liver Cancer by a Mechanism Involving P21 and FOXM1

Simple Summary

The tumor suppressor protein P53 is a major player in preventing liver cancer development and progression. In this study we could show that P53 negatively regulates the expression of Helicase, lymphoid specific (HELLS), previously described as an important pro-tumorigenic epigenetic regulator in hepatocarcinogenesis. The regulatory mechanism included induction of the P53 target gene P21 (CDKN1A) resulting in repression of HELLS via downregulation of the transcription factor Forkhead Box Protein M1 (FOXM1). Our in vitro and in vivo findings indicate an important additional aspect of the tumor suppressive function of P53 in liver cancer linked to epigenetic regulation.

Abstract

The major tumor suppressor P53 (TP53) acts primarily as a transcription factor by activating or repressing subsets of its numerous target genes, resulting in different cellular outcomes (e.g., cell cycle arrest, apoptosis and senescence). P53-dependent gene regulation is linked to several aspects of chromatin remodeling; however, regulation of chromatin-modifying enzymes by P53 is poorly understood in hepatocarcinogenesis. Herein, we identified Helicase, lymphoid specific (HELLS), a major epigenetic regulator in liver cancer, as a strong and selective P53 repression target within the SNF2-like helicase family. The underlying regulatory mechanism involved P53-dependent induction of P21 (CDKN1A), leading to repression of Forkhead Box Protein M1 (FOXM1) that in turn resulted in downregulation of HELLS expression. Supporting our in vitro data, we found higher expression of HELLS in murine HCCs arising in a Trp53−/− background compared to Trp53+/+ HCCs as well as a strong and highly significant correlation between HELLS and FOXM1 expression in different HCC patient cohorts. Our data suggest that functional or mutational inactivation of P53 substantially contributes to overexpression of HELLS in HCC patients and indicates a previously unstudied aspect of P53′s ability to suppress liver cancer formation.

Spectrum of microRNAs and their target genes in cancer: intervention in diagnosis and therapy

Till date, several groups have studied the mechanism of microRNA (miRNA) biogenesis, processing, stability, silencing, and their dysregulation in cancer. The miRNA coding genes recurrently go through abnormal amplification, deletion, transcription, and epigenetic regulation in cancer. Some miRNAs function as tumor promoters while few others are tumor suppressors based on the transcriptional regulation of target genes. A review of miRNAs and their target genes in a wide range of cancers is attempted in this article, which may help in the development of new diagnostic tools and intervention therapies. The contribution of miRNAs for drug sensitivity or resistance in cancer therapy and opportunities of miRNAs in cancer prognosis or diagnosis and therapy is also presented in detail.

HSC and miRNA Regulation with Implication for Foetal Haemoglobin Induction in Beta Haemoglobinopathies

Sickle cell disease (SCD) is one of the most common haemoglobinopathies worldwide, with up to 70 % of global SCD annual births occurring in sub-Saharan Africa. Reports have shown that 50 to 80 % of affected children in these countries die annually. Efforts geared towards understanding and controlling HbF production in SCD patients could lead to strategies for effective control of globin gene expression and therapeutic approaches that could be beneficial to individuals with haemoglobinopathies. Hemopoietic stem cells (HSCs) are characterized by a specific miRNA signature in every state of differentiation. The role of miRNAs has become evident both in the maintenance of the "stemness" and in the early induction of differentiation by modulation of the expression of the master pluripotency genes and during early organogenesis. miRNAs are extra regulatory mechanisms in hematopoietic stem cells (HSCs) via influencing transcription profiles together with transcript stability. miRNAs have been reported to be used to reprogram primary somatic cells toward pluripotency. Their involvement in cell editing holds the potential for therapy for many genetic diseases. This review provides a snapshot of miRNA involvement in cell fate decisions, haemoglobin induction pathway, and their journey as some emerge prime targets for therapy in beta haemoglobinopathies.

The anti-tumor effects of CT-26 derived exosomes enriched by MicroRNA-34a on murine model of colorectal cancer

AIMS

As conventional therapeutics failed to provide satisfied outcomes against one of the most prevalent cancers, colorectal cancer (CRC), we purposed to implicate MicroRNA (miR)-34a, as a major tumor suppressor, to be delivered by tumor-derived exosomes (TEXs) and investigated its anti-tumor functions in-vivo.

MAIN METHODS

TEXs were isolated from CT-26 cell line and loaded with miR-34a mimic. Then, mice bearing CRC were treated with miR-34a-enriched TEX (TEX-miR-34a) and then examined for the relative tumor-suppressive impacts of the TEX as well as its potential in promoting an anti-tumor immune response.

KEY FINDINGS

TEX-miR-34a significantly reduced tumor size and prolonged survival of mice bearing CRC. TEX-miR-34a was able to diminish gene expressions related to invasion, angiogenesis and immune evasion. It was also capable of inducing T cell polarization toward CD8+ T subsets among tumor-infiltrating lymphocytes, draining lymph nodes (DLNs) and spleen cells. Moreover, cytotoxic T cells were professionally induced in mice receiving TEX-miR-34a and the secretion of interleukin (IL)-6, IL-17A and tumor necrosis factor (TGF)-β was reduced in DLNs. However, the enhanced levels of interferon-γ were evaluated in DLN and spleen displaying the polarization of anti-tumor immune responses. Interestingly, mice receiving TEX alone showed a noticeable reduction in certain oncogenic gene expressions as well as IL-17A secretion in DLNs.

SIGNIFICANCE

TEX-miR-34a demonstrated the potential to induce beneficial anti-tumor immune responses and TEXs, aside from the delivery function of miRNA, revealed certain anti-tumor beneficial characteristics which could introduce TEX-miR-34a as a promising approach in CRC combination therapies.

Implication of ARID1A Undercurrents and PDL1, TP53 Overexpression in Advanced Gastric Cancer

AT-rich interactive domain-containing protein 1A (ARID1A), TP53 and programmed cell death-ligand 1 (PDL1) are involved in several protein interactions that regulate the expression of various cancer-related genes involved in the progression of the cell cycle, cell proliferation, DNA repair, and apoptosis. In addition, gene expression analysis identified some common downstream targets of ARID1A and TP53. It has been established that tumors formed by ARID1A-deficient cancer cells exhibited elevated PDL1 expression. However, the aberrations in these molecules have not been studied in this population especially in Gastric Cancer (GC). In this backdrop we aimed to investigate the role of the ARID1A mutation and expression of ARID1A, TP53 and PDL1 genes in the etiopathogenesis of Gastric Cancer (GC) in the ethnic Kashmiri population (North India). The study included 103 histologically confirmed GC cases. The mutations, if any, in exon-9 of ARID1A gene was analysed by Polymerase Chain Reaction (PCR) followed by Sanger sequencing. The mRNA expression of the ARID1A, TP53 and PDL1 genes was analysed by Quantitative real time-PCR (qRT-PCR). We identified a nonsense mutation (c.3219; C > T) in exon-9 among two GC patients (∼2.0%), which introduces a premature stop codon at protein position 1073. The mRNA expression of the ARID1A, TP53 and PDL1 gene was significantly reduced in 25.3% and elevated in 47.6 and 39.8% of GC cases respectively with a mean fold change of 0.63, 2.93 and 2.43. The data revealed that reduced mRNA expression of ARID1A and elevated mRNA expression of TP53 and PDL1 was significantly associated with the high-grade and advanced stage of cancer. Our study proposes that ARAD1A under-expression and overexpression of TP53 and PDL1 might be crucial for tumor progression with TP53 and PDL1 acting synergistically.

The miR-34a/WNT7B modulates the sensitivity of cholangiocarcinoma cells to p53-mediated photodynamic therapy toxicity

Photodynamic therapy (PDT) provides apparent survival benefits for unresectable cholangiocarcinoma patients. the insufficient sensitivity of cancer cell to PDT treatment limits the clinical application. In this study, according to the GEO datasets, WNT7B expression was decreased by PDT treatment in cholangiocarcinoma samples. In cholangiocarcinoma cells, PDT treatment inhibited Wnt signaling, suppressed cell viability, and enhanced cell apoptosis. Within cholangiocarcinoma cells, PDT treatment induced p53 and miR-34a-5p expression. Under PDT treatment, p53 knockdown downregulated miR-34a-5p expression, whereas the inhibition effect of p53 knockdown on miR-34a-5p could be partially attenuated by agomir-34a-5p. p53 knockdown enhanced cell viability and suppressed cell apoptosis, whereas miR-34a-5p overexpression exerted opposite effects; miR-34a-5p overexpression partially attenuated p53 knockdown effects on PDT-treated cholangiocarcinoma cells. miR-34a-5p directly targeted WNT7B and inhibited WNT7B expression. Under PDT treatment, WNT7B knockdown inhibited the Wnt signaling and cell viability, and promoted cell apoptosis, while miR-34a-5p suppression showed the opposite trends; WNT7B knockdown partially attenuated miR-34a-5p inhibition effects on PDT-treated cholangiocarcinoma cells. In conclusion, PDT treatment induces p53-induced miR-34a transactivation to inhibit cholangiocarcinoma cell proliferation; the miR-34a-5p/WNT7B axis and Wnt signaling are involved.

Regulating Polyamine Metabolism by miRNAs in Diabetic Cardiomyopathy

PURPOSE OF REVIEW

Insulin is at the heart of diabetes mellitus (DM). DM alters cardiac metabolism causing cardiomyopathy, ultimately leading to heart failure. Polyamines, organic compounds synthesized by cardiomyocytes, have an insulin-like activity and effect on glucose metabolism, making them metabolites of interest in the DM heart. This review sheds light on the disrupted microRNA network in the DM heart in relation to developing novel therapeutics targeting polyamine biosynthesis to prevent/mitigate diabetic cardiomyopathy.

RECENT FINDINGS

Polyamines prevent DM-induced upregulation of glucose and ketone body levels similar to insulin. Polyamines also enhance mitochondrial respiration and thereby regulate all major metabolic pathways. Non-coding microRNAs regulate a majority of the biological pathways in our body by modulating gene expression via mRNA degradation or translational repression. However, the role of miRNA in polyamine biosynthesis in the DM heart remains unclear. This review discusses the regulation of polyamine synthesis and metabolism, and its impact on cardiac metabolism and circulating levels of glucose, insulin, and ketone bodies. We provide insights on potential roles of polyamines in diabetic cardiomyopathy and putative miRNAs that could regulate polyamine biosynthesis in the DM heart. Future studies will unravel the regulatory roles these miRNAs play in polyamine biosynthesis and will open new doors in the prevention/treatment of adverse cardiac remodeling in diabetic cardiomyopathy.

Metformin Increases Sensitivity of Melanoma Cells to Cisplatin by Blocking Exosomal-Mediated miR-34a Secretion

Melanoma, also known as malignant melanoma, is a type of cancer derived from the pigment-containing cells known as melanocytes. Cisplatin (CDDP) is widely used in the treatment of different types of tumors with high response rates, but it generally has low efficiency in melanoma. This study aimed to investigate whether metformin could sensitize the melanoma cell line A375 to cisplatin. Our results for the first time indicated that CDDP increased the miR-34a secretion by exosomes in melanoma A375 cells, which was, at least partially, related to the cisplatin resistance of melanoma cells. Moreover, metformin significantly sensitized A375 cells to cisplatin. Mechanistically, metformin significantly blocked the exosome-mediated miR-34a secretion induced by cisplatin. Our study not only reveals a novel mechanism that exosomal secretion of miR-34a is involved in the cisplatin resistance of melanoma cells but also provides a promising therapeutic strategy by synergistic addition of metformin.

Characterization of miR-34a-Induced Epithelial-Mesenchymal Transition in Non-Small Lung Cancer Cells Focusing on p53

Background: Epithelial–mesenchymal transition (EMT), a phenotypic conversion of the epithelial to mesenchymal state, contributes to cancer progression. Currently, several microRNAs (miRNAs) are associated with EMT-mediated cancer progression, but the contribution of miR-34a to EMT in cancer cells remains controversial. The present study aimed to clarify the role of miR-34a in the EMT-related phenotypes of human non-small cell lung cancer (NSCLC) cell lines, A549 (p53 wild-type) and H1299 (p53-deficient). Methods: The miR-34a mimic and p53 small interfering RNA (siRNA) were transfected into the cells using Lipofectamine, and the obtained total RNA and cell lysates were used for real-time polymerase chain reaction and Western blotting analysis, respectively. Results: The introduction of the miR-34a mimic led to an increase in the mRNA and protein expression levels of α-smooth muscle actin (α-SMA), a mesenchymal marker gene, in A549, but not in H1299 cells. Additionally, miR-34a-induced the upregulation of p53 activity and migration was observed in A549, but not in H1299 cells. However, under the p53-knockdown condition, only α-SMA upregulation by miR-34a was abolished. Conclusion: These findings indicate a close relationship between p53 and miR-34a-induced EMT in p53-wild type NSCLC cells, which provides novel insights about the role of miR-34a in EMT-like phenotypic changes in NSCLC.

Expression of Selected microRNAs in Migraine: A New Class of Possible Biomarkers of Disease?

Preliminary but convergent findings suggest a role for microRNAs (miRNAs) in the generation and maintenance of chronic pain and migraine. Initial observations showed that serum levels of miR-382-5p and miR-34a-5p expression were increased in serum during the migraine attack, with miR-382-5p increasing in the interictal phase as well. By contrast, miR-30a-5p levels were lower in migraine patients compared to healthy controls. Of note, antimigraine treatments proved to be capable of influencing the expression of these miRNAs. Altogether, these observations suggest that miRNAs may represent migraine biomarkers, but several points are yet to be elucidated. A major concern is that these miRNAs are altered in a broad spectrum of painful and non-painful conditions, and thus it is not possible to consider them as truly “migraine-specific” biomarkers. We feel that these miRNAs may represent useful tools to uncover and define different phenotypes across the migraine spectrum with different treatment susceptibilities and clinical features, although further studies are needed to confirm our hypothesis. In this narrative review we provide an update and a critical analysis of available data on miRNAs and migraines in order to propose possible interpretations. Our main objective is to stimulate research in an area that holds promise when it comes to providing reliable biomarkers for theoretical and practical scientific advances.

A novel approach to identify the mechanism of miR-145-5p toxicity to podocytes based on the essential genes targeting analysis

MicroRNAs (miRNAs) are emerging as effective therapeutic agents. When testing whether miR-145-5p could alleviate kidney injury, we unexpectedly found that extracellular vesicles loaded with miR-145-5p induced proteinuria and podocyte foot process effacement in normal control mice. To explore the mechanism of miR-145-5p’s toxicity to podocytes, we hypothesized that miR-145-5p could enter podocytes and inhibit genes essential for podocytes. We demonstrated that systemically administered miRNA can enter podocytes. Next, we predicted 611 podocyte essential genes based on single-cell RNA sequencing (RNA-seq) and found that 32 of them are predicted to be targeted by miR-145-5p. Functional annotation of the 32 podocyte essential genes revealed small GTPase-mediated signal transduction as the top pathway. We experimentally validated that miR-145-5p targeted Arhgap24 and Srgap1, the essential regulators of the Rho family of small GTPases, increased the activity of Rac1 and Cdc42, and reduced RhoA activity, accompanied by cellular injury, in podocytes. These results explain how miR-145-5p has deleterious effect on podocytes. Most importantly, our study provides a novel approach to investigate how a miRNA affects a given cell type, allowing not only identification of the molecular mechanism underlying an observed side effect of a miRNA drug but also prediction of miRNA drug toxicity on various cell types.

Dual roles of SIRT1 in the BAX switch through the P53 module: A mathematical modeling study

SIRT1 is a multifunctional deacetylase that participates in a variety of cellular physiological processes to cope with stress. The anticancer protein P53 is an important target of SIRT1. It has been found that SIRT1 is involved in apoptosis by regulating the activity and intracellular location of P53. Moreover, P53-dependent apoptosis is inseparable from the BCL-2 protein family. Among the members of this family, BAX’s switching dynamics may play a key role in apoptosis. Therefore, a challenging question arises: what effect does SIRT1 have on the BAX switch? To answer this question, we built a small-scale protein network model. Through computer simulation, the properties of SIRT1 that on the one hand promote and on the other inhibit apoptosis are revealed. We found that the opening time of the BAX switch will be delayed in the case of either SIRT1 excess or deficiency. Similarly, the stimulus threshold required for apoptosis will also increase in the above two scenarios. Thereby, we proposed that SIRT1 has an optimal content at which the probability of apoptosis is greatest. In addition, P53 oscillation requires the concentration of SIRT1 to be higher than the optimal value. This work may be helpful both experimentally and clinically.

Dysregulated MicroRNAs as Biomarkers or Therapeutic Targets in Cisplatin-Induced Nephrotoxicity: A Systematic Review

The purpose of this systematic review was to map out and summarize scientific evidence on dysregulated microRNAs (miRNAs) that can be possible biomarkers or therapeutic targets for cisplatin nephrotoxicity and have already been tested in humans, animals, or cells. In addition, an in silico analysis of the two miRNAs found to be dysregulated in the majority of studies was performed. A literature search was performed using eight databases for studies published up to 4 July 2021. Two independent reviewers selected the studies and extracted the data; disagreements were resolved by a third and fourth reviewers. A total of 1002 records were identified, of which 30 met the eligibility criteria. All studies were published in English and reported between 2010 and 2021. The main findings were as follows: (a) miR-34a and miR-21 were the main miRNAs identified by the studies as possible biomarkers and therapeutic targets of cisplatin nephrotoxicity; (b) the in silico analysis revealed 124 and 131 different strongly validated targets for miR-34a and miR-21, respectively; and (c) studies in humans remain scarce.

miR-34a-5p functions as a tumor suppressor in head and neck squamous cell cancer progression by targeting Flotillin-2

While a number of therapeutic advances have been made in recent years, the overall survival of patients with head and neck squamous cell cancer (HNSCC) remains poor. MicroRNAs (miRNAs) are key drivers of oncogenic progression, with miR-34a-5p downregulation having been observed in many different tumor types. Here, we assessed the link between miR-34a-5p and HNSCC progression and the mechanistic basis for this relationship. Levels of miR-34a-5p in HNSCC tumors and cell lines were assessed via qPCR, after which we explored the functional importance of this miRNA in this oncogenic setting. Through luciferase reporter assays, the ability of miR-34a-5p to regulate flotillin-2 (FLOT-2) was further clarified. Overall, these analyses revealed that HNSCC tumors and cells exhibited marked miR-34a-5p downregulation that was linked to the progression of this tumor type. At a functional level, miR-34a-5p constrained the proliferation, migratory/invasive activity, and epithelial-mesenchymal transition induction in HNSCC cells. At the mechanistic level, miR-34a-5p was found to suppress FLOT-2 expression and to activate the MEK/ERK1/2 pathway. Overall, these results suggest that miR-34a-5p can function as a tumor suppressor miRNA in HNSCC owing to its ability to target FLOT-2, highlighting the promise of targeting this regulatory axis to treat HNSCC.

The genotypic and phenotypic impact of hypoxia microenvironment on glioblastoma cell lines

BACKGROUND

Glioblastoma is a fatal brain tumour with a poor patient survival outcome. Hypoxia has been shown to reprogram cells towards a stem cell phenotype associated with self-renewal and drug resistance properties. Activation of hypoxia-inducible factors (HIFs) helps in cellular adaptation mechanisms under hypoxia. Similarly, miRNAs are known to be dysregulated in GBM have been shown to act as critical mediators of the hypoxic response and to regulate key processes involved in tumorigenesis.

METHODS

Glioblastoma (GBM) cells were exposed to oxygen deprivation to mimic a tumour microenvironment and different cell aspects were analysed such as morphological changes and gene expression of miRNAs and survival genes known to be associated with tumorigenesis.

RESULTS

It was observed that miR-128a-3p, miR-34-5p, miR-181a/b/c, were down-regulated in 6 GBM cell lines while miR-17-5p and miR-221-3p were upregulated when compared to a non-GBM control. When the same GBM cell lines were cultured under hypoxic microenvironment, a further 4-10-fold downregulation was observed for miR-34-5p, miR-128a-3p and 181a/b/c while a 3-6-fold upregulation was observed for miR-221-3p and 17-5p for most of the cells. Furthermore, there was an increased expression of SOX2 and Oct4, GLUT-1, VEGF, Bcl-2 and survivin, which are associated with a stem-like state, increased metabolism, altered angiogenesis and apoptotic escape, respectively.

CONCLUSION

This study shows that by mimicking a tumour microenvironment, miRNAs are dysregulated, stemness factors are induced and alteration of the survival genes necessary for the cells to adapt to the micro-environmental factors occurs. Collectively, these results might contribute to GBM aggressiveness.

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.

Regulatory Non-Coding RNAs Modulate Transcriptional Activation During B Cell Development

B cells play a significant role in the adaptive immune response by secreting immunoglobulins that can recognize and neutralize foreign antigens. They develop from hematopoietic stem cells, which also give rise to other types of blood cells, such as monocytes, neutrophils, and T cells, wherein specific transcriptional programs define the commitment and subsequent development of these different cell lineages. A number of transcription factors, such as PU.1, E2A, Pax5, and FOXO1, drive B cell development. Mounting evidence demonstrates that non-coding RNAs, such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), modulate the expression of these transcription factors directly by binding to the mRNA coding for the transcription factor or indirectly by modifying cellular pathways that promote expression of the transcription factor. Conversely, these transcription factors upregulate expression of some miRNAs and lncRNAs to determine cell fate decisions. These studies underscore the complex gene regulatory networks that control B cell development during hematopoiesis and identify new regulatory RNAs that require additional investigation. In this review, we highlight miRNAs and lncRNAs that modulate the expression and activity of transcriptional regulators of B lymphopoiesis and how they mediate this regulation.

Tumor Suppressor miRNA in Cancer Cells and the Tumor Microenvironment: Mechanism of Deregulation and Clinical Implications

MicroRNAs (miRNAs) are noncoding RNAs that have been identified as important posttranscriptional regulators of gene expression. miRNAs production is controlled at multiple levels, including transcriptional and posttranscriptional regulation. Extensive profiling studies have shown that the regulation of mature miRNAs expression plays a causal role in cancer development and progression. miRNAs have been identified to act as tumor suppressors (TS) or as oncogenes based on their modulating effect on the expression of their target genes. Upregulation of oncogenic miRNAs blocks TS genes and leads to tumor formation. In contrast, downregulation of miRNAs with TS function increases the translation of oncogenes. Several miRNAs exhibiting TS properties have been studied. In this review we focus on recent studies on the role of TS miRNAs in cancer cells and the tumor microenvironment (TME). Furthermore, we discuss how TS miRNA impacts the aggressiveness of cancer cells, with focus of the mechanism that regulate its expression. The study of the mechanisms of miRNA regulation in cancer cells and the TME may paved the way to understand its critical role in the development and progression of cancer and is likely to have important clinical implications in a near future. Finally, the potential roles of miRNAs as specific biomarkers for the diagnosis and the prognosis of cancer and the replacement of tumor suppressive miRNAs using miRNA mimics could be promising approaches for cancer therapy.

Enhanced IFNα Signaling Promotes Ligand-Independent Activation of ERα to Promote Aromatase Inhibitor Resistance in Breast Cancer

Aromatase inhibitors (AIs) reduce estrogen levels up to 98% as the standard practice to treat postmenopausal women with estrogen receptor-positive (ER+) breast cancer. However, approximately 30% of ER+ breast cancers develop resistance to treatment. Enhanced interferon-alpha (IFNα) signaling is upregulated in breast cancers resistant to AIs, which drives expression of a key regulator of survival, interferon-induced transmembrane protein 1 (IFITM1). However, how upregulated IFNα signaling mediates AI resistance is unknown. In this study, we utilized MCF-7:5C cells, a breast cancer cell model of AI resistance, and demonstrate that these cells exhibit enhanced IFNα signaling and ligand-independent activation of the estrogen receptor (ERα). Experiments demonstrated that STAT1, the mediator of intracellular signaling for IFNα, can interact directly with ERα. Notably, inhibition of IFNα signaling significantly reduced ERα protein expression and ER-regulated genes. In addition, loss of ERα suppressed IFITM1 expression, which was associated with cell death. Notably, chromatin immunoprecipitation experiments validated that both ERα and STAT1 associate with ERE sequences in the IFITM1 promoter. Overall, hyperactivation of IFNα signaling enhances ligand-independent activation of ERα, which promotes ER-regulated, and interferon stimulated gene expression to promote survival in AI-resistant breast cancer cells.

Analyzing the whole-transcriptome profiles of ncRNAs and predicting the competing endogenous RNA networks in cervical cancer cell lines with cisplatin resistance

Background

Cervical cancer (CC) is one of the most common malignant tumors in women. In order to identify the functional roles and the interaction between mRNA and non-coding RNA (ncRNA, including lncRNA, circRNA and miRNA) in CC cisplatin (DDP) resistance, the transcription profile analysis was performed and a RNA regulatory model of CC DDP resistance was proposed.

Methods

In this study, whole-transcriptome sequencing analysis was conducted to study the ncRNA and mRNA profiles of parental SiHa cells and DDP resistant SiHa/DDP cells. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed for pathway analysis based on the selected genes with significant differences in expression. Subsequently, ceRNA network analyses were conducted using the drug resistance-related genes and signal-transduction pathways by Cytoscape software. Furthermore, a ceRNA regulatory pathway, namely lncRNA-AC010198.2/hsa-miR-34b-3p/STC2, was selected by RT-qPCR validation and literature searching. Further validation was done by both dual-luciferase reporter gene assays and RNA pull-down assays. Besides that, the changes in gene expression and biological function were further studied by performing si-AC010198.2 transfection and DDP resistance analyses in the SiHa and SiHa/DDP cells, respectively.

Results

Using bioinformatics and dual-luciferase reporter gene analyses, we found that AC010198.2/miR-34b-3p/STC2 may be a key pathway for DDP resistance in CC cells. Significant differences in both downstream gene expression and the biological function assays including colony formation, migration efficiency and cell apoptosis were identified in AC010198.2 knockdown cells.

Conclusions

Our study will not only provide new markers and potential mechanism models for CC DDP resistance, but also discover novel targets for attenuating it.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02239-6.

Nucleic Acid Drugs-Current Status, Issues, and Expectations for Exosomes

Simple Summary

Nucleic acid drugs provide novel therapeutic modalities with characteristics that differ from those of small molecules and antibodies. In this review, I focus on the various mechanisms through which nucleic acid drugs act on, the status of their clinical development, and discuss several hurdles that need to be surmounted. In addition, by listing examples of how the progress in exosome biology can lead to the solution of problems in nucleic acid drug therapy, I hope that many more nucleic acid drugs including anticancer drugs will be developed in the future.

Abstract

Nucleic acid drugs are being developed as novel therapeutic modalities. They have great potential to treat human diseases such as cancers, viral infections, and genetic disorders due to unique characteristics that make it possible to approach undruggable targets using classical small molecule or protein/antibody-based biologics. In this review, I describe the advantages, classification, and clinical status of nucleic acid therapeutics. To date, more than 10 products have been launched, and many products have been tested in clinics. To promote the use of nucleic acid therapeutics such as antibodies, several hurdles need to be surmounted. The most important issue is the delivery of nucleic acids and several other challenges have been reported. Recent advanced delivery platforms are lipid nanoparticles and ligand conjugation approaches. With the progress of exosome biology, exosomes are expected to contribute to the solution of various problems associated with nucleic acid drugs.

MicroRNA-34a activation in tuberous sclerosis complex during early brain development may lead to impaired corticogenesis

AIMS

Tuberous sclerosis complex (TSC) is a genetic disorder associated with dysregulation of the mechanistic target of rapamycin complex 1 (mTORC1) signalling pathway. Neurodevelopmental disorders, frequently present in TSC, are linked to cortical tubers in the brain. We previously reported microRNA-34a (miR-34a) among the most upregulated miRs in tubers. Here, we characterised miR-34a expression in tubers with the focus on the early brain development and assessed the regulation of mTORC1 pathway and corticogenesis by miR-34a.

METHODS

We analysed the expression of miR-34a in resected cortical tubers (n = 37) compared with autopsy-derived control tissue (n = 27). The effect of miR-34a overexpression on corticogenesis was assessed in mice at E18. The regulation of the mTORC1 pathway and the expression of the bioinformatically predicted target genes were assessed in primary astrocyte cultures from three patients with TSC and in SH-SY5Y cells following miR-34a transfection.

RESULTS

The peak of miR-34a overexpression in tubers was observed during infancy, concomitant with the presence of pathological markers, particularly in giant cells and dysmorphic neurons. miR-34a was also strongly expressed in foetal TSC cortex. Overexpression of miR-34a in mouse embryos decreased the percentage of cells migrated to the cortical plate. The transfection of miR-34a mimic in TSC astrocytes negatively regulated mTORC1 and decreased the expression of the target genes RAS related (RRAS) and NOTCH1.

CONCLUSIONS

MicroRNA-34a is most highly overexpressed in tubers during foetal and early postnatal brain development. miR-34a can negatively regulate mTORC1; however, it may also contribute to abnormal corticogenesis in TSC.

The role of microRNA-34 family in Alzheimer's disease: A potential molecular link between neurodegeneration and metabolic disorders

Growing evidence indicates that overexpression of the microRNA-34 (miR-34) family in the brain may play a crucial role in Alzheimer's disease (AD) pathogenesis by targeting and downregulating genes associated with neuronal survival, synapse formation and plasticity, Aβ clearance, mitochondrial function, antioxidant defense system, and energy metabolism. Additionally, elevated levels of the miR-34 family in the liver and pancreas promote the development of metabolic syndromes (MetS), such as diabetes and obesity. Importantly, MetS represent a well-documented risk factor for sporadic AD. This review focuses on the recent findings regarding the role of the miR-34 family in the pathogenesis of AD and MetS, and proposes miR-34 as a potential molecular link between both disorders. A comprehensive understanding of the functional roles of miR-34 family in the molecular and cellular pathogenesis of AD brains may lead to the discovery of a breakthrough treatment strategy for this disease.

CancerMIRNome: an interactive analysis and visualization database for miRNome profiles of human cancer

MicroRNAs (miRNAs), which play critical roles in gene regulatory networks, have emerged as promising diagnostic and prognostic biomarkers for human cancer. In particular, circulating miRNAs that are secreted into circulation exist in remarkably stable forms, and have enormous potential to be leveraged as non-invasive biomarkers for early cancer detection. Novel and user-friendly tools are desperately needed to facilitate data mining of the vast amount of miRNA expression data from The Cancer Genome Atlas (TCGA) and large-scale circulating miRNA profiling studies. To fill this void, we developed CancerMIRNome, a comprehensive database for the interactive analysis and visualization of miRNA expression profiles based on 10 554 samples from 33 TCGA projects and 28 633 samples from 40 public circulating miRNome datasets. A series of cutting-edge bioinformatics tools and machine learning algorithms have been packaged in CancerMIRNome, allowing for the pan-cancer analysis of a miRNA of interest across multiple cancer types and the comprehensive analysis of miRNome profiles to identify dysregulated miRNAs and develop diagnostic or prognostic signatures. The data analysis and visualization modules will greatly facilitate the exploit of the valuable resources and promote translational application of miRNA biomarkers in cancer. The CancerMIRNome database is publicly available at http://bioinfo.jialab-ucr.org/CancerMIRNome.

Cadmium chloride induces non-alcoholic fatty liver disease in rats by stimulating miR-34a/SIRT1/FXR/p53 axis

Cadmium (Cd) is associated with non-alcoholic fatty liver disease (NAFLD). The hepatic activation of p53/miR-43a-induced suppression of SIRT1/FXR axis plays a significant role in the development of NAFLD. In this study, we have investigated CdCl₂-induced NAFLD in rats involves activation of miR34a/SIRT1/FXR axis. Adult male rats were divided into 4 groups (n-8/each) as a control, CdCl₂ (10 mg/l), CdCl₂ + miR-34a antagomir (inhibitor), and CdCl₂ + SRT1720 (a SIRT1 activator) for 8 weeks, daily. With no effect on fasting glucose and insulin levels, CdCl₂ significantly reduced rats' final body, fat pads, and liver weights, and food intake. Concomitantly, it increased the circulatory levels of liver markers (ALT, AST, and γ-GTT), increased the serum and hepatic levels of total cholesterol and triglycerides coincided with increased hepatic lipid accumulation. Besides, it increased the mRNA and protein levels of SREBP1, SREBP2, FAS, and HMGCOA reductase but reduced mRNA levels of PPARα, CPT1, and CPT2. Interestingly, CdCl₂ also increased mRNA levels of miR34 without altering mRNA levels of SIRT1 but with a significant reduction in protein levels of SIRT1. These effects were associated with increased total protein levels of p53 and acetylated protein of p53, and FXR. Of note, suppressing miR-34a with a specific anatomic or activating SIRT1 by SRT1720 completely prevented all these effects and reduced hepatic fat accumulations in the livers of rats. In conclusion, CdCl₂ induced NAFLD by increasing the transcription of miR-34a which in turn downregulates SIRT1 at the translational level.

TP53 in Biology and Treatment of Osteosarcoma

The TP53 gene is mutated in 50% of human tumors. Oncogenic functions of mutant TP53 maintain tumor cell proliferation and tumor growth also in osteosarcomas. We collected data on TP53 mutations in patients to indicate which are more common and describe their role in in vitro and animal models. We also describe animal models with TP53 dysfunction, which provide a good platform for testing the potential therapeutic approaches. Finally, we have indicated a whole range of pharmacological compounds that modulate the action of p53, stabilize its mutated versions or lead to its degradation, cause silencing or, on the contrary, induce the expression of its functional version in genetic therapy. Although many of the described therapies are at the preclinical testing stage, they offer hope for a change in the approach to osteosarcoma treatment based on TP53 targeting in the future.