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

Premature MicroRNA-Based Therapeutic: A "One-Two Punch" against Cancers

Simple Summary

The current understanding of miRNA biology is greatly derived from studies on the guide strands and the passenger strands, also called miRNAs*, which are considered as carriers with no sense for long periods. As such, various studies alter the expression of guide strands by manipulating the expression of their primary transcripts or precursors, both of which are premature miRNAs. In this situation, the regulatory miRNA* species may interfere with the phenotypic interpretation against the target miRNA. However, such methods could manipulate the expression of two functionally synergistic miRNAs of the same precursor, leading to therapeutic potential against various diseases, including cancers. Premature miRNAs represent an underappreciated target reservoir and provide molecular targets for “one-two punch” against cancers. Examples of targetable miRNA precursors and available targeting strategies are provided in this review.

Abstract

Up-to-date knowledge regarding the biogenesis and functioning of microRNAs (miRNAs) has provided a much more comprehensive and concrete view of miRNA biology than anyone ever expected. Diverse genetic origins and biogenesis pathways leading to functional miRNAs converge on the synthesis of ≈21-nucleotide RNA duplex, almost all of which are processed from long premature sequences in a DICER- and/or DROSHA-dependent manner. Formerly, it was assumed that one mature strand of the duplex is preferentially selected for entry into the silencing complex, and the paired passenger strands (miRNA*) are subjected to degradation. However, given the consolidated evidence of substantial regulatory activity of miRNA* species, currently, this preconception has been overturned. Here, we see the caveat and opportunity toward exogenously manipulating the expression of premature miRNA, leading to simultaneous upregulation or downregulation of dual regulatory strands due to altered expressions. The caveat is the overlooked miRNA* interference while manipulating the expression of a target miRNA at the premature stage, wherein lies the opportunity. If the dual strands of a pre-miRNA function synergistically, the overlooked miRNA* interference may inversely optimize the therapeutic performance. Insightfully, targeting the premature miRNAs may serve as the “one-two punch” against diseases, especially cancers, and this has been discussed in detail in this review.

MicroRNAs at the Crossroad of the Dichotomic Pathway Cell Death vs. Stemness in Neural Somatic and Cancer Stem Cells: Implications and Therapeutic Strategies

Stemness and apoptosis may highlight the dichotomy between regeneration and demise in the complex pathway proceeding from ontogenesis to the end of life. In the last few years, the concept has emerged that the same microRNAs (miRNAs) can be concurrently implicated in both apoptosis-related mechanisms and cell differentiation. Whether the differentiation process gives rise to the architecture of brain areas, any long-lasting perturbation of miRNA expression can be related to the occurrence of neurodevelopmental/neuropathological conditions. Moreover, as a consequence of neural stem cell (NSC) transformation to cancer stem cells (CSCs), the fine modulation of distinct miRNAs becomes necessary. This event implies controlling the expression of pro/anti-apoptotic target genes, which is crucial for the management of neural/neural crest-derived CSCs in brain tumors, neuroblastoma, and melanoma. From a translational point of view, the current progress on the emerging miRNA-based neuropathology therapeutic applications and antitumor strategies will be disclosed and their advantages and shortcomings discussed.

The Emerging Role of miRNAs for the Radiation Treatment of Pancreatic Cancer

Simple Summary

Pancreatic cancer is an aggressive disease with a high mortality rate. Radiotherapy is one treatment option within a multimodal therapy approach for patients with locally advanced, non-resectable pancreatic tumors. However, radiotherapy is only effective in about one-third of the patients. Therefore, biomarkers that can predict the response to radiotherapy are of utmost importance. Recently, microRNAs, small non-coding RNAs regulating gene expression, have come into focus as there is growing evidence that microRNAs could serve as diagnostic, predictive and prognostic biomarkers in various cancer entities, including pancreatic cancer. Moreover, their high stability in body fluids such as serum and plasma render them attractive candidates for non-invasive biomarkers. This article describes the role of microRNAs as suitable blood biomarkers and outlines an overview of radiation-induced microRNAs changes and the association with radioresistance in pancreatic cancer.

Abstract

Today, pancreatic cancer is the seventh leading cause of cancer-related deaths worldwide with a five-year overall survival rate of less than 7%. Only 15–20% of patients are eligible for curative intent surgery at the time of diagnosis. Therefore, neoadjuvant treatment regimens have been introduced in order to downsize the tumor by chemotherapy and radiotherapy. To further increase the efficacy of radiotherapy, novel molecular biomarkers are urgently needed to define the subgroup of pancreatic cancer patients who would benefit most from radiotherapy. MicroRNAs (miRNAs) could have the potential to serve as novel predictive and prognostic biomarkers in patients with pancreatic cancer. In the present article, the role of miRNAs as blood biomarkers, which are associated with either radioresistance or radiation-induced changes of miRNAs in pancreatic cancer, is discussed. Furthermore, the manuscript provides own data of miRNAs identified in a pancreatic cancer mouse model as well as radiation-induced miRNA changes in the plasma of tumor-bearing mice.

MicroRNA Biomarkers in Canine Diffuse Large B-Cell Lymphoma

Lymphoma is among the most common cancer in dogs. Diffuse large B-cell lymphoma (DLBCL) is the predominant type, accounting for up to half of all cases. Definitive diagnosis of DLBCL relies on cytologic evaluation with immunophenotyping, or histopathology and immunohistochemistry when needed. A rapid and specific molecular test aiding in the diagnosis could be beneficial. Noncoding microRNAs (miRNAs) are regulators of gene expression involved in a variety of cellular processes, including cell differentiation, cell cycle progression, and apoptosis. Not surprisingly, miRNA expression is aberrant in diseases such as cancers. Their high stability and abundance in tissues make them promising biomarkers for diagnosing and monitoring diseases. This study aimed to identify miRNA signatures of DLBCL to develop ancillary molecular diagnostic tools. miRNA was isolated from formalin-fixed, paraffin-embedded lymph node tissue from 22 DLBCL and 14 nonneoplastic controls. Relative gene expression of 8 tumor-regulating miRNAs was achieved by RT-qPCR (reverse transcriptase quantitative polymerase chain reaction). The results showed downregulation of the let-7 family of miRNAs and miR-155, whereas miR-34a was upregulated in DLBCL compared to the controls. We demonstrated that the combination of expression levels of miR-34a and let-7f or of let-7b and let-7f achieved 100% differentiation between DLBCL and controls. Furthermore, let-7f alone discriminated DLBCL from nonneoplastic tissue in 97% of cases. Our results represent one step forward in search of a rapid and accurate ancillary diagnostic test for DLBCL in dogs.

microRNAs Biogenesis, Functions and Role in Tumor Angiogenesis

microRNAs (miRNAs) are small non-coding RNA molecules, evolutionary conserved. They target more than one mRNAs, thus influencing multiple molecular pathways, but also mRNAs may bind to a variety of miRNAs, either simultaneously or in a context-dependent manner. miRNAs biogenesis, including miRNA transcription, processing by Drosha and Dicer, transportation, RISC biding, and miRNA decay, are finely controlled in space and time. miRNAs are critical regulators in various biological processes, such as differentiation, proliferation, apoptosis, and development in both health and disease. Their dysregulation is involved in tumor initiation and progression. In tumors, they can act as onco-miRNAs or oncosuppressor-miRNA participating in distinct cellular pathways, and the same miRNA can perform both activities depending on the context. In tumor progression, the angiogenic switch is fundamental. miRNAs derived from tumor cells, endothelial cells, and cells of the surrounding microenvironment regulate tumor angiogenesis, acting as pro-angiomiR or anti-angiomiR. In this review, we described miRNA biogenesis and function, and we update the non-classical aspects of them. The most recent role in the nucleus, as transcriptional gene regulators and the different mechanisms by which they could be dysregulated, in tumor initiation and progression, are treated. In particular, we describe the role of miRNAs in sprouting angiogenesis, vessel co-option, and vasculogenic mimicry. The role of miRNAs in lymphoma angiogenesis is also discussed despite the scarcity of data. The information presented in this review reveals the need to do much more to discover the complete miRNA network regulating angiogenesis, not only using high-throughput computational analysis approaches but also morphological ones.

Ligation of 2', 3'-cyclic phosphate RNAs for the identification of microRNA binding sites

Identifying the targetome of a microRNA is key for understanding its functions. Cross‐linking and immunoprecipitation (CLIP) methods capture native miRNA‐mRNA interactions in cells. Some of these methods yield small amounts of chimeric miRNA‐mRNA sequences via ligation of 5′‐phosphorylated RNAs produced during the protocol. Here, we introduce chemically synthesized microRNAs (miRNAs) bearing 2′‐, 3′‐cyclic phosphate groups, as part of a new CLIP method that does not require 5′‐phosphorylation for ligation. We show in a system that models miRNAs bound to their targets, that addition of recombinant bacterial ligase RtcB increases ligation efficiency, and that the transformation proceeds via a 3′‐phosphate intermediate. By optimizing the chemistry underlying ligation, we provide the basis for an improved method to identify miRNA targetomes.

Life and Death Decision-Making by p53 and Implications for Cancer Immunotherapy

The tumor-suppressor protein p53 is mutated in approximately half of all cancers, whereas the p53 signaling network is perturbed in almost all cancers. In response to different stress stimuli, p53 selectively activates genes to elicit a cell survival or cell death response. How p53 makes the decision between life and death remains a fascinating question and an exciting field of research. Understanding how this decision is made has major implications for improving cancer treatments, particularly in recently evolved immune checkpoint inhibition therapy. We highlight progress and challenges in understanding the mechanisms governing the p53 life and death decision-making process, and discuss how this decision is relevant to immune system regulation. Finally, we discuss how knowledge of the p53 pro-survival and pro-death decision node can be applied to optimize immune checkpoint inhibitor therapy for cancer treatment.

Non coding RNAs as the critical factors in chemo resistance of bladder tumor cells

BACKGROUND

Bladder cancer (BCa) is the ninth frequent and 13th leading cause of cancer related deaths in the world which is mainly observed among men. There is a declining mortality rates in developed countries. Although, the majority of BCa patients present Non-Muscle-Invasive Bladder Cancer (NMIBC) tumors, only 30% of patients suffer from muscle invasion and distant metastases. Radical cystoprostatectomy, radiation, and chemotherapy have proven to be efficient in metastatic tumors. However, tumor relapse is observed in a noticeable ratio of patients following the chemotherapeutic treatment. Non-coding RNAs (ncRNAs) are important factors during tumor progression and chemo resistance which can be used as diagnostic and prognostic biomarkers of BCa.

MAIN BODY

In present review we summarized all of the lncRNAs and miRNAs associated with chemotherapeutic resistance in bladder tumor cells.

CONCLUSIONS

This review paves the way of introducing a prognostic panel of ncRNAs for the BCa patients which can be useful to select a proper drug based on the lncRNA profiles of patients to reduce the cytotoxic effects of chemotherapy in such patients.

Roles of exosomal miRNA in vascular aging

Aging is a major risk factor for human diseases. As global average life expectancy has lengthened, delaying or reducing aging and age-related diseases has become an urgent issue for improving the quality of life. The vascular aging process represents an important link between aging and age-related diseases. Exosomes are small extracellular vesicles (EV) that can be secreted by almost all eukaryotic cells, and they deliver characteristic biological information about donor cells to regulate the cellular microenvironment, mediate signal transmission between neighboring or distant cells, and affect the expression of target genes in recipient cells. Many recent studies have shown that exosomal microribonucleic acids (miRNA) are involved in the regulation of vascular aging by participating in the physiological functions of vascular cells and the destruction and remodeling of the extracellular matrix (ECM). This review summarizes the regulatory functions of exosomal miRNA in vascular aging because they interact with the ECM, and participate in vascular cell senescence, and the regulation of senescence-related functions such as proliferation, migration, apoptosis, inflammation, and differentiation.

The multifaceted roles of microRNAs in differentiation

MicroRNAs (miRNAs) are major drivers of cell fate specification and differentiation. The post-transcriptional regulation of key molecular factors by microRNAs contributes to the progression of embryonic and postembryonic development in several organisms. Following the discovery of lin-4 and let-7 in Caenorhabditis elegans and bantam microRNAs in Drosophila melanogaster, microRNAs have emerged as orchestrators of cellular differentiation and developmental timing. Spatiotemporal control of microRNAs and associated protein machinery can modulate microRNA activity. Additionally, adaptive modulation of microRNA expression and function in response to changing environmental conditions ensures that robust cell fate specification during development is maintained. Herein, we review the role of microRNAs in the regulation of differentiation during development.

The Role of Noncoding RNAs in B-Cell Lymphoma

In recent years, emerging evidence has suggested that noncoding RNAs (ncRNAs) participate in nearly every aspect of biological processes and play a crucial role in the genesis and progression of numerous tumors, including B-cell lymphoma. The exploration of ncRNA dysregulations and their functions in B-cell lymphoma provides new insights into lymphoma pathogenesis and is essential for indicating future clinical trials and optimizing the diagnostic and therapeutic strategies. In this review, we summarize the role of ncRNAs in B-cell lymphoma and discuss their potential in clinical applications.

Role of Nurr1 in Carcinogenesis and Tumor Immunology: A State of the Art Review

Simple Summary

Nuclear receptor related-1 protein (Nurr1) emerges as a therapeutic target in multiple malignancies and immunotherapies. Previous studies have highlighted its association with clinicopathological parameters, tumorigenesis and therapeutic resistance in cancers. In addition, recent studies unraveled its contribution to the suppression of antitumor immunity, suggesting that inhibition of Nurr1 is a potential method to repress cancer aggressiveness and disrupt tumor immune tolerance. In line with this evidence, the present review provides the roles of Nurr1 in tumor progression and the associated underlying molecular mechanisms. Moreover, the significance of Nurr1 in promoting immune tolerance and potential strategies for Nurr1 inhibition are highlighted.

Abstract

Nuclear receptor related-1 protein (Nurr1), coded by an early response gene, is involved in multiple cellular and physiological functions, including proliferation, survival, and self-renewal. Dysregulation of Nurr1 has been frequently observed in many cancers and is attributed to multiple transcriptional and post-transcriptional mechanisms. Besides, Nurr1 exhibits extensive crosstalk with many oncogenic and tumor suppressor molecules, which contribute to its potential pro-malignant behaviors. Furthermore, Nurr1 is a key player in attenuating antitumor immune responses. It not only potentiates immunosuppressive functions of regulatory T cells but also dampens the activity of cytotoxic T cells. The selective accessibility of chromatin by Nurr1 in T cells is closely associated with cell exhaustion and poor efficacy of cancer immunotherapy. In this review, we summarize the reported findings of Nurr1 in different malignancies, the mechanisms that regulate Nurr1 expression, and the downstream signaling pathways that Nurr1 employs to promote a wide range of malignant phenotypes. We also give an overview of the association between Nurr1 and antitumor immunity and discuss the inhibition of Nurr1 as a potential immunotherapeutic strategy.

Circulating exosomal microRNAs as emerging non-invasive clinical biomarkers in heart failure: Mega bio-roles of a nano bio-particle

Exosomes are nano-sized extracellular vesicles containing a cell-specific biologically active cargo of proteins and genetic materials. Exosomes are constitutively released from almost all cell-types and affect neighboring or distant cells through a complex intercellular exchange of the genetic information and/or regulation of certain gene expressions that change the function and behavior of recipient cells. Those released into body fluids are the major mediators of intercellular communications. The success of the biological functions of exosomes is highly mediated by the effective transfer of microRNAs (miRs). Exosomes secreted by a damaged or diseased heart can exhibit alterations in the miRs' profile that may reflect the cellular origin and (patho)physiological state, as a "signature" or "fingerprint" of the donor cell. It has been shown that the transportation of cardiac-specific miRs in exosomes can be rapidly detected and measured, holding great potential as biomarkers in heart diseases. Currently, the search for new biomarkers of heart diseases remains a large and increasing enterprise. Notably, circulating exosomal miRs (Exo-miRs) have successfully gained huge interests for their diagnostic and prognostic potentials. The present review highlights circulating Exo-miRs explored for diagnosis/prognosis and outcome prediction in patients with heart failure (HF). To this end, we explain the feasibility of exosomes as clinical biomarkers, discuss the priority of circulating Exo-miRs over non-exosomal ones as a biomarker, and then outline reported circulating Exo-miRs having the biomarker function in HF patients, together with their mechanism of action. In conclusion, circulating Exo-miRs represent emerging diagnostic (Exo-miR-92b-5p, Exo-miR-146a, Exo-miR-181c, and Exo-miR-495) and prognostic (Exo-miR-192, Exo-miR-194, Exo-miR-34a, Exo-miR-425, Exo-miR-744) biomarkers for HF.

Analysis of microRNA-34a expression profile and rs2666433 variant in colorectal cancer: a pilot study

MicroRNAs (miRNAs) are implicated in every stage of carcinogenesis and play an essential role as genetic biomarkers of cancer. We aimed to evaluate microRNA-34a gene (MIR34A) expression in colorectal cancer (CRC) tissues compared with non-cancer one and to preliminarily explore the association of one related variant to CRC risk. A total of 116 paraffin-embedded colon specimens were enrolled. MiR-34a was quantified by qPCR, and rs2666433 (A/G) genotyping was performed by TaqMan Real-Time PCR. Also, the somatic mutation burden was assessed. MIR34A expression in the CRC specimens was significantly upregulated (median = 21.50, IQR: 7.0–209.2; P = 0.001) relative to the non-cancer tissues. Allele (A) was highly prevalent in CRC tissues represented 0.56 (P < 0.001). AA/AG genotype carriers were 5.7 and 2.8 more likely to develop cancer than GG carriers. Tumor-normal tissue paired analysis revealed genotype concordance in 33 out of 58 tissue samples. Approximately 43% of the specimens showed a tendency for G to A shift. Additionally, a higher frequency of somatic mutation (92%) was observed in adenocarcinoma (P = 0.006). MIR34A expression and gene variant did not show associations with the clinicopathological data. However, G > A somatic mutation carriers had more prolonged DFS and OS. Bioinformatics analysis revealed miR-34a could target 30 genes that are implied in all steps of CRC tumorigenesis. In conclusion, this study confirms MIR34A upregulation in CRC tissues, and its rs2666433 (A/G) variant showed association with CRC and a high somatic mutation rate in cancer tissues. MiR-34a could provide a novel targeted therapy after validation in large-scale studies.

The Impact of Adipose Tissue-Derived miRNAs in Metabolic Syndrome, Obesity, and Cancer

Obesity is a multifactorial and complex condition that is characterized by abnormal and excessive white adipose tissue accumulation, which can lead to the development of metabolic diseases, such as type 2 diabetes mellitus, nonalcoholic fatty liver disease, cardiovascular diseases, and several types of cancer. Obesity is characterized by excessive adipose tissue accumulation and associated with alterations in immunity, displaying a chronic low-grade inflammation profile. Adipose tissue is a dynamic and complex endocrine organ composed not only by adipocytes, but several immunological cells, which can secrete hormones, cytokines and many other factors capable of regulating metabolic homeostasis and several critical biological pathways. Remarkably, adipose tissue is a major source of circulating microRNAs (miRNAs), recently described as a novel form of adipokines. Several adipose tissue-derived miRNAs are deeply associated with adipocytes differentiation and have been identified with an essential role in obesity-associated inflammation, insulin resistance, and tumor microenvironment. During obesity, adipose tissue can completely change the profile of the secreted miRNAs, influencing circulating miRNAs and impacting the development of different pathological conditions, such as obesity, metabolic syndrome, and cancer. In this review, we discuss how miRNAs can act as epigenetic regulators affecting adipogenesis, adipocyte differentiation, lipid metabolism, browning of the white adipose tissue, glucose homeostasis, and insulin resistance, impacting deeply obesity and metabolic diseases. Moreover, we characterize how miRNAs can often act as oncogenic and tumor suppressor molecules, significantly modulating cancer establishment and progression. Furthermore, we highlight in this manuscript how adipose tissue-derived miRNAs can function as important new therapeutic targets.

Downregulation of miR-10a inhibits cutaneous squamous cell carcinoma cell proliferation, migration, and invasion by targeting Syndecan-1

BACKGROUND

Cutaneous squamous cell carcinoma (cSCC) is a malignancy of epidermal keratinocytes which accounts for approximately one-third of skin cancer-related death yearly. In this study, we aim to investigate the mechanism of miR-10a in regulating cellular function of cSCC cells and its possible role in prognosis of cSCC.

METHODS

The expression of miR-10a was detected by qRT-PCR. Target mRNA candidates were detected by bioinformatic analysis. Proliferative and migration capability of cSCC cell were examined by MTT assay, wound healing assay, and invasion assay, respectively. miR-10a expression was monitored in cSCC patients to elucidate the relationship between miR-10a expression and outcomes of cSCC.

RESULTS

In our study, we found that expression of miR-10a was significantly down-regulated in cSCC cell in vitro and in vivo. Moreover, our results revealed that SDC-1 was a likely target of miR-10a in regulating biologic function of cSCC cell. Additionally, miR-10a expression level was inversely correlated with cSCC cell differentiation and tumor progression.

CONCLUSION

These findings in this study indicate the importance of miR-10a in cSCC cell hallmarks and its use as a novel target for cSCC treatment.

Interleukin-1β Triggers p53-Mediated Downmodulation of CCR5 and HIV-1 Entry in Macrophages through MicroRNAs 103 and 107

Macrophages are a target of human immunodeficiency virus type 1 (HIV-1) and may serve as a viral reservoir during antiretroviral therapy (ART). Their susceptibility to HIV-1 infection is subject to variations from permissiveness to resistance depending on their origin, tissue localization, and polarization profile. This is in part due to the expression of regulatory microRNAs. Here, we identify two microRNA paralogs, microRNA 103 (miR-103) and miR-107, as regulators of CCR5 expression that are upregulated in noninfected bystander cells of HIV-1-infected-monocyte-derived macrophage (MDM) cultures. Transfection of microRNA 103 mimics in MDMs reduced CCR5 expression levels and inhibited CCR5-dependent HIV-1 entry, whereas the corresponding antagomirs enhanced virus spread in HIV-infected MDMs. Treatment of MDMs with interleukin-1β (IL-1β) enhanced microRNA 103 expression, a condition that we found contributed to the reduction of CCR5 mRNA in IL-1β-exposed MDMs. Interestingly, we show that the induction of miR-103/107 expression is part of a tumor suppressor p53 response triggered by secreted IL-1β that renders macrophages refractory to HIV-1 entry. In a more physiological context, the levels of microRNAs 103 and 107 were found enriched in tissue-resident colon macrophages of healthy donors and alveolar macrophages of individuals under antiretroviral therapy, conceivably contributing to their relative resistance to HIV-1 infection. Overall, these findings highlight the role of p53 in enforcing proinflammatory antiviral responses in macrophages, at least in part, through miR-103/107-mediated downmodulation of CCR5 expression and HIV-1 entry.IMPORTANCE Macrophages are heterogeneous immune cells that display varying susceptibilities to HIV-1 infection, in part due to the expression of small noncoding microRNAs involved in the posttranscriptional regulation of gene expression and silencing. Here, we identify microRNAs 103 and 107 as important p53-regulated effectors of the antiviral response triggered by the proinflammatory cytokine IL-1β in macrophages. These microRNAs, which are enriched in colon macrophages of healthy donors and alveolar macrophages of HIV-infected individuals under antiretroviral therapy, act as inhibitors of HIV-1 entry through their capacity to downregulate the CCR5 coreceptor. These results highlight the important role played by miR-103/107 in modulating CCR5 expression and HIV-1 entry in macrophages. They further underscore a distinct function of the tumor suppressor p53 in enforcing proinflammatory antiviral responses in macrophages, thus providing insight into a cellular pathway that could be targeted to limit the establishment of viral reservoirs in these cells.

The Oncogenic Kaposi's Sarcoma-Associated Herpesvirus Encodes a Mimic of the Tumor-Suppressive miR-15/16 miRNA Family

Many tumor viruses encode oncogenes of cellular origin. Here, we report an oncoviral mimic of a cellular tumor suppressor. The Kaposi’s sarcoma-associated herpesvirus (KSHV) microRNA (miRNA) miR-K6-5p shares sequence similarity to the tumor-suppressive cellular miR-15/16 miRNA family. We show that miR-K6-5p inhibits cell cycle progression, a hallmark function of miR-16. miR-K6-5p regulates conserved miR-15/16 family miRNA targets, including many cell cycle regulators. Inhibition of miR-K6-5p in KSHV-transformed B cells confers a significant growth advantage. Altogether, our data show that KSHV encodes a functional mimic of miR-15/16 family miRNAs. While it is exceedingly well established that oncogenic viruses encode oncogenes of cellular origin, this is an unusual example of an oncogenic virus that encodes a viral mimic of a cellular tumor suppressor. Encoding a tumor-suppressive miRNA could help KSHV balance viral oncogene expression and thereby avoid severe pathogenesis in the healthy host.

Morrison et al. report that the tumor virus KSHV encodes a mimic of a cellular tumor suppressor. KSHV miR-K6-5p phenocopies miR-16-induced cell cycle inhibition, shares mRNA targets and binding sites with miR-16, and negatively regulates proliferation in KSHV-infected cells.

Reversal of diet-induced hepatic steatosis by peripheral CB1 receptor blockade in mice is p53/miRNA-22/SIRT1/PPARα dependent

OBJECTIVE

The endocannabinoid (eCB) system is increasingly recognized as being crucially important in obesity-related hepatic steatosis. By activating the hepatic cannabinoid-1 receptor (CB₁R), eCBs modulate lipogenesis and fatty acid oxidation. However, the underlying molecular mechanisms are largely unknown.

METHODS

We combined unbiased bioinformatics techniques, mouse genetic manipulations, multiple pharmacological, molecular, and cellular biology approaches, and genomic sequencing to systematically decipher the role of the hepatic CB₁R in modulating fat utilization in the liver and explored the downstream molecular mechanisms.

RESULTS

Using an unbiased normalized phylogenetic profiling analysis, we found that the CB₁R evolutionarily coevolves with peroxisome proliferator-activated receptor-alpha (PPARα), a key regulator of hepatic lipid metabolism. In diet-induced obese (DIO) mice, peripheral CB₁R blockade (using AM6545) induced the reversal of hepatic steatosis and improved liver injury in WT, but not in PPARα^-/- mice. The antisteatotic effect mediated by AM6545 in WT DIO mice was accompanied by increased hepatic expression and activity of PPARα as well as elevated hepatic levels of the PPARα-activating eCB-like molecules oleoylethanolamide and palmitoylethanolamide. Moreover, AM6545 was unable to rescue hepatic steatosis in DIO mice lacking liver sirtuin 1 (SIRT1), an upstream regulator of PPARα. Both of these signaling molecules were modulated by the CB₁R as measured in hepatocytes exposed to lipotoxic conditions or treated with CB₁R agonists in the absence/presence of AM6545. Furthermore, using microRNA transcriptomic profiling, we found that the CB₁R regulated the hepatic expression, acetylation, and transcriptional activity of p53, resulting in the enhanced expression of miR-22, which was found to specifically target SIRT1 and PPARα.

CONCLUSIONS

We provide strong evidence for a functional role of the p53/miR-22/SIRT1/PPARα signaling pathway in potentially mediating the antisteatotic effect of peripherally restricted CB₁R blockade.

Neural reprogramming via microRNAs: the new kid on the p53-deficient block

We recently reported a novel role for nerve-cancer crosstalk, demonstrating that tumor protein p53 (TP53) deficiency in head and neck squamous cell carcinoma leads to a decrease in miR-34a in tumor-shed vesicles. This directed sensory nerve reprogramming in the tumor microenvironment which enhanced tumor growth.

Determination of certain urinary microRNAs as promising biomarkers in diabetic nephropathy patients using gold nanoparticles

Diabetic nephropathy (DN) is a major leading cause of kidney failure. So, early detection of DN by assessing urinary microRNAs (miRNAs) expression may be of clinical value. In this study, the diagnostic value of two urinary miRNAs (miR-210 & miR-34a) as biomarkers for diagnosis of DN was assessed using a simple colorimetric gold nanoparticle (AuNP) assay and real-time PCR. MiR-(210 & 34a) were markedly up-regulated in DN groups (micro-albuminuric and macro-albuminuric groups) compared to the non-albuminuric group and healthy controls. The sensitivity and specificity for the qualitative detection of urinary miR-(210 & 34a) using the AuNP assay were (78% and 72%) & (81% and 69%), respectively, which were consistent with the results of real-time PCR. There was a highly significant correlation between urinary miR-(210 & 34a) detected by either qRT-PCR or qualitative AuNP assay. Accordingly, this simple AuNP assay may be considered a valid test for the detection of these two urinary miRNAs as potential biomarkers that can aid in the noninvasive diagnosis of DN.

Expression of miR-34a is a sensitive biomarker for exposure to genotoxic agents in human lymphoblastoid TK6 cells

miR-34a has been identified as a tumor suppressor microRNA (miRNA) involved in the P53 network. Its expression levels correlate to carcinogenesis, which are generally lower in tumor tissue and higher in response to DNA damage. In this study, the response of miR-34a from exposure to genotoxic agents in human lymphoblastoid TK6 cells was evaluated to assess whether the expression of this miRNA could be used as an early indicator for genotoxic damage in mammalian cells. TK6 cells were treated with seven genotoxic agents with different mode-of-actions (cisplatin, N-ethyl-N-nitrosourea, etoposide, mitomycin C, methyl methanesulphonate, taxol, and X-ray radiation) and a non-genetic toxin (usnic acid) at different concentrations for four hours (except for X-rays) and the expression levels of miR-34a were measured 24 h after the beginning of the treatments. The expression levels of miR-34a were significantly increased by these genetic toxins in a dose-dependent manner, while no significant change in miRNA expression was found in the usnic acid-treated cells. These results suggest that miR-34a can respond to genotoxic insults sensitively; thus, miR-34a expression has the potential to be used to evaluate genotoxicity of agents.

miRNA-103 promotes chondrocyte apoptosis by down-regulation of Sphingosine kinase-1 and ameliorates PI3K/AKT pathway in osteoarthritis

OBJECTIVES

The aim of the present study was to determine the effects of miRNA-103 on chondrocyte apoptosis and molecular mechanisms in osteoarthritis (OA) progression.

METHODS

The cell proliferation, apoptosis, and recovery ability were measured by cell counting kit-8 (CCK-8), flow cytometry, and wound healing assays. The interaction of miRNA-103 and Sphingosine kinase-1 (SPHK1) were determined by using luciferase reporter assay. The expression of mRNA and proteins were measured by qRT-PCR and Western blot. OA rat model was established by surgery stimulation.

RESULTS

miRNA-103 expression was significantly increased in the cartilage of OA patients and surgery-induced OA rat models. miRNA-103 transfection into primary rat chondrocytes reduced SPHK1 expression, induced apoptosis, inhibited cell proliferation, and impeded scratch assay wound closure. Moreover, expression of total AKT, and p-AKT were significantly reduced in miRNA-103-overexpressing chondrocytes while SPHK1 up-regulation increased the expression of phosphatidylinsitol-3-kinase (PI3K) and p-AKT, and reversed the proliferation suppression induced by the miRNA-103 mimic.

CONCLUSIONS

Our studies suggest that miRNA-103 contributes to chondrocyte apoptosis, promoting OA progression by down-regulation of PI3K/AKT pathway through the reduction in SPHK1 activity.

Identification of miPEP133 as a novel tumor-suppressor microprotein encoded by miR-34a pri-miRNA

BACKGROUND

Very few proteins encoded by the presumed non-coding RNA transcripts have been identified. Their cellular functions remain largely unknown. This study identifies the tumor-suppressor function of a novel microprotein encoded by the precursor of miR-34a. It consists of 133 amino acid residues, thereby named as miPEP133 (pri-microRNA encoded peptide 133).

METHODS

We overexpressed miPEP133 in nasopharyngeal carcinoma (NPC), ovarian cancer and cervical cancer cell lines to determine its effects on cell growth, apoptosis, migration, or invasion. Its impact on tumor growth was evaluated in a xenograft NPC model. Its prognostic value was analyzed using NPC clinical samples. We also conducted western blot, immunoprecipitation, mass spectrometry, confocal microscopy and flow cytometry to determine the underlying mechanisms of miPEP133 function and regulation.

RESULTS

miPEP133 was expressed in normal human colon, stomach, ovary, uterus and pharynx. It was downregulated in cancer cell lines and tumors. miPEP133 overexpression induced apoptosis in cancer cells and inhibited their migration and invasion. miPEP133 inhibited tumor growth in vivo. Low miPEP133 expression was an unfavorable prognostic marker associated with advanced metastatic NPC. Wild-type p53 but not mutant p53 induced miPEP133 expression. miPEP133 enhanced p53 transcriptional activation and miR-34a expression. miPEP133 localized in the mitochondria to interact with mitochondrial heat shock protein 70kD (HSPA9) and prevent HSPA9 from interacting with its binding partners, leading to the decrease of mitochondrial membrane potential and mitochondrial mass.

CONCLUSION

miPEP133 is a tumor suppressor localized in the mitochondria. It is a potential prognostic marker and therapeutic target for multiple types of cancers.

Non-coding RNAs, guardians of the p53 galaxy

The TP53 gene is arguably the most important tumor suppressor gene known, contributing multifaceted roles to the process of tumor development. Its protein product p53, is a crucial sequence-specific transcription factor which regulates the expression of a large network of protein-coding genes, as well as thousands of noncoding RNAs (ncRNAs), notably microRNAs and long ncRNAs (lncRNAs). Through a variety of direct and indirect mechanisms, ncRNAs in turn modulate p53 levels and activity. Here the numbers of studies are steadily building which link the contributions of dysregulated ncRNAs to tumorigenesis via their participation throughout the p53 regulatory network. In this review, we will examine how the principal forms of ncRNAs, namely microRNAs, lncRNAs and circular RNAs (circRNAs) function as either effectors or regulators amongst the diversity of p53's cellular responses. We first discuss the more recently discovered connections between miRNAs and p53 signaling before focusing on the remarkable diversity of crosstalk evident between lncRNAs and p53, and subsequently, developing reports linking circRNAs to p53. Highlighted throughout the review are the mechanistic impacts of dysregulated ncRNAs on p53 functions as well as the possible prognostic implications of these interactions. We also describe the emerging connections between ncRNAs and the often-perplexing functions of mutant p53. Finally, in the context of p53 therapeutic approaches, we describe some of the challenges in ncRNA research and their potential for translation.

A systematic study of critical miRNAs on cells proliferation and apoptosis by the shortest path

BACKGROUND

MicroRNAs are a class of important small noncoding RNAs, which have been reported to be involved in the processes of tumorigenesis and development by targeting a few genes. Existing studies show that the imbalance between cell proliferation and apoptosis is closely related to the initiation and development of cancers. However, the impact of miRNAs on this imbalance has not been studied systematically.

RESULTS

In this study, we first construct a cell fate miRNA-gene regulatory network. Then, we propose a systematical method for calculating the global impact of miRNAs on cell fate genes based on the shortest path. Results on breast cancer and liver cancer datasets show that most of the cell fate genes are perturbed by the differentially expressed miRNAs. Most of the top-identified miRNAs are verified in the Human MicroRNA Disease Database (HMDD) and are related to breast and liver cancers. Function analysis shows that the top 20 miRNAs regulate multiple cell fate related function modules and interact tightly based on their functional similarity. Furthermore, more than half of them can promote sensitivity or induce resistance to some anti-cancer drugs. Besides, survival analysis demonstrates that the top-ranked miRNAs are significantly related to the overall survival time in the breast and liver cancers group.

CONCLUSION

In sum, this study can help to systematically study the important role of miRNAs on proliferation and apoptosis and thereby uncover the key miRNAs during the process of tumorigenesis. Furthermore, the results of this study will contribute to the development of clinical therapy based miRNAs for cancers.

Chidamide acts on the histone deacetylase-mediated miR-34a/Bcl-2 axis to regulate NB4 cell line proliferation and apoptosis

Acute promyelocytic leukemia (APL), a biologically and clinically distinct variant of acute myelogenous leukemia, is characterized by the fusion of the N-terminus of promyelocytic leukemia protein to the C terminus of retinoic acid receptor alpha, mostly due to chromosomal translocation t(15;17). Chidamide, a synthetic analogue of MS-275 identified from a group of benzamide-type compounds, has been found to have efficient anticancer activity in basic and clinical research studies. However, the concrete role and underlying mechanism of Chidamide in the treatment of APL has not been well characterized. Our data demonstrate that Chidamide inhibited the expression of histone deacetylase (HDAC) to induce apoptosis and suppress proliferation in NB4 cells. Mechanistically, Chidamide increases the expression of miR-34a by suppressing HDAC. Furthermore, B-cell lymphoma-2 (Bcl-2) is a direct target of miR-34a, the expression of which is regulated by miR-34a. Functionally, Chidamide inhibits cell proliferation and promotes apoptosis through miR-34a/Bcl-2. Chidamide exerts its anticancer effect via the HDAC-mediated miR-34a/Bcl-2 axis, providing potential targets for APL therapy.

Recent trends in targeting miRNAs for cancer therapy

OBJECTIVES

MicroRNAs (miRNAs) are a type of small noncoding RNA employed by the cells for gene regulation. A single miRNA, typically 22 nucleotides in length, can regulate the expression of numerous genes. Over the past decade, the study of miRNA biology in the context of cancer has led to the development of new diagnostic and therapeutic opportunities.

KEY FINDINGS

MicroRNA dysregulation is commonly associated with cancer, in part because miRNAs are actively involved in the mechanisms like genomic instabilities, aberrant transcriptional control, altered epigenetic regulation and biogenesis machinery defects. MicroRNAs can regulate oncogenes or tumour suppressor genes and thus when altered can lead to tumorigenesis. Expression profiling of miRNAs has boosted the possibilities of application of miRNAs as potential cancer biomarkers and therapeutic targets, although the feasibility of these approaches will require further validation.

SUMMARY

In this review, we will focus on how miRNAs regulate tumour development and the potential applications of targeting miRNAs for cancer therapy.

Multifunctional Roles of miR-34a in Cancer: A Review with the Emphasis on Head and Neck Squamous Cell Carcinoma and Thyroid Cancer with Clinical Implications

MiR-34a belongs to the class of small non-coding regulatory RNAs and functions as a tumor suppressor. Under physiological conditions, miR-34a has an inhibitory effect on all processes related to cell proliferation by targeting many proto-oncogenes and silencing them on the post-transcriptional level. However, deregulation of miR-34a was shown to play important roles in tumorigenesis and processes associated with cancer progression, such as tumor-associated epithelial-mesenchymal transition, invasion, and metastasis. Moreover, further understanding of miR-34a molecular mechanisms in cancer are indispensable for the development of effective diagnosis and treatments. In this review, we summarized the current knowledge on miR-34a functions in human disease with an emphasis on its regulation and dysregulation, its role in human cancer, specifically head and neck squamous carcinoma and thyroid cancer, and emerging role as a disease diagnostic and prognostic biomarker and the novel therapeutic target in oncology.

The differences of immunologic and TP53 mutant phenotypes between synchronous and metachronous head and neck cancer and esophageal cancer

OBJECTIVE

To determine the tumor genomic, immunologic expression, and risk factors of treatment outcomes for patients with double head and neck squamous cell carcinoma (HNSCC) and esophageal squamous cell carcinoma (ESCC).

METHODS

We reviewed patients with double HNSCC and ESCC between 1995 and 2014. The TP53 genomic mutation, CD8+ tumor infiltrating lymphocytes (TIL) and tumor programmed cell death ligand 1 (PD-L1) expression of paired HNSCC and ESCC were analyzed.

RESULTS

A total of 116 patients (57 metachronous and 59 synchronous) were included. There were 88 (75.86%) patients with HNSCC and 80 (68.97%) with ESCC harboured TP53 disruptive mutation. Nearly 106 (91.38%) patients had different clonality of TP53 mutation in paired HNSCC and ESCC. The immunologic expression of synchronous and metachronous patients was significantly different. Compared to the metachronous patients, the synchronous patients had significantly higher HNSCC CD8+ TIL (p = 0.03), ESCC CD8+ TIL (p < 0.001), HNSCC PD-L1+ tumor proportion score (TPS, p = 0.04), and ESCC PD-L1+ TPS (p = 0.04). Furthermore, among the synchronous patients, the immunologic expression between HNSCC and ESCC was significantly correlated. The CD8+ TIL and PD-L1 TPS had strongly (r = 0.63, p < 0.0001) and moderately (r = 0.42, p = 0.001) positive correlations, respectively. Finally, advanced stage (III/IV) HNSCC was a significant factor for disease-free (p = 0.03) and overall survival (p = 0.005).

CONCLUSION

In patients with double HNSCC and ESCC, nearly all HNSCC and ESCC were of multicentric origin. For the synchronous patients, there was more adaptive immune resistance in HNSCC and ESCC. The immunologic expression between paired HNSCC and ESCC was also significantly correlated.

Regulatory and immunomodulatory role of miR-34a in T cell immunity

miRNAs are a class of non-coding RNAs and very conserve molecules that negatively regulate the expression of many genes by targeting the 3' UTR of mRNAs. miRNAs are involved in the modulation of T-cell biology during the earliest and last stages and key controllers of T-cell differentiation and function. The miR-34a, as a major hub of the regulatory network of T cells, plays an important role in T cell activation. miR-34a is widely expressed in immune cells (dendritic cells, macrophages, mast cells, B cells, and T cells) and regulates their development, function, and survival. This miRNA, by targeting over 30 genes across different cellular pathways controls immune response. miR-34a expression is controlled by p53 in transcription level. As well as, miR-34a by activating dendritic cells mediates innate immune response and increases tumor-infiltrating CD8 expression T lymphocytes. In various types of cancers and autoimmune diseases, miR-34a can regulate T cell function and become a possible significant target of microRNA-based therapy. Therefore, in this review, we focus on miR-34a-related regulatory mechanisms in T cell function and understanding mechanisms and molecules involved in this network.

Development of MicroRNAs as Potential Therapeutics against Cancer

MicroRNAs (miRNAs) are small noncoding RNAs that function at the posttranscriptional level in the cellular regulation process. miRNA expression exerts vital effects on cell growth such as cell proliferation and survival. In cancers, miRNAs have been shown to initiate carcinogenesis, where overexpression of oncogenic miRNAs (oncomiRs) or reduced expression of tumor suppressor miRNAs has been reported. In this review, we discuss the involvement of miRNAs in tumorigenesis, the role of synthetic miRNAs as either mimics or antagomirs to overcome cancer growth, miRNA delivery, and approaches to enhance their therapeutic potentials.

A systems approach delivers a functional microRNA catalog and expanded targets for seizure suppression in temporal lobe epilepsy

Temporal lobe epilepsy is the most common drug-resistant form of epilepsy in adults. The reorganization of neural networks and the gene expression landscape underlying pathophysiologic network behavior in brain structures such as the hippocampus has been suggested to be controlled, in part, by microRNAs. To systematically assess their significance, we sequenced Argonaute-loaded microRNAs to define functionally engaged microRNAs in the hippocampus of three different animal models in two species and at six time points between the initial precipitating insult through to the establishment of chronic epilepsy. We then selected commonly up-regulated microRNAs for a functional in vivo therapeutic screen using oligonucleotide inhibitors. Argonaute sequencing generated 1.44 billion small RNA reads of which up to 82% were microRNAs, with over 400 unique microRNAs detected per model. Approximately half of the detected microRNAs were dysregulated in each epilepsy model. We prioritized commonly up-regulated microRNAs that were fully conserved in humans and designed custom antisense oligonucleotides for these candidate targets. Antiseizure phenotypes were observed upon knockdown of miR-10a-5p, miR-21a-5p, and miR-142a-5p and electrophysiological analyses indicated broad safety of this approach. Combined inhibition of these three microRNAs reduced spontaneous seizures in epileptic mice. Proteomic data, RNA sequencing, and pathway analysis on predicted and validated targets of these microRNAs implicated derepressed TGF-β signaling as a shared seizure-modifying mechanism. Correspondingly, inhibition of TGF-β signaling occluded the antiseizure effects of the antagomirs. Together, these results identify shared, dysregulated, and functionally active microRNAs during the pathogenesis of epilepsy which represent therapeutic antiseizure targets.

Soy Isoflavone Genistein Impedes Cancer Stemness and Mesenchymal Transition in Head and Neck Cancer through Activating miR-34a/RTCB Axis

Genistein, a soy-derived phytoestrogen, has been shown to exhibit anti-neoplastic activities in various cancers. Nevertheless, its effects on the elimination of tumor-initiating cells of head and neck cancer (HNC-TICs) remain unclear. Here, we investigated the inhibitory effect of genistein on HNC-TICs and potential mechanisms. Our results demonstrated that genistein lowered the proliferation of HNC-TICs by examining the percentage of ALDH1+ or CD44+ cells. Aside from the downregulation of epithelial-mesenchymal transition (EMT) in HNC-TICs, genistein restricted their tumor propagating capacities in a dose-dependent fashion. Moreover, genistein potentiated cell death caused by three commonly used chemotherapeutic agents (doxorubicin, cisplatin, and 5-FU). Our findings proved that genistein induced ROS production through upregulation of miR-34a, leading to apoptosis in HNC-TICs. The genistein-elicited miR-34a reduced self-renewal, migration, invasion capacities and ALDH1 activity, which may be partly owing to the repression of EMT. Furthermore, we showed that RTCB was a novel target that was negatively regulated by miR-34a and involved in the tumor repressive effect of genistein. Besides, the in vivo study validated that genistein retarded tumor growth through the elevation of miR-34a and suppression of RTCB. These results suggested that genistein-induced miR-34a contributed to the ROS-associated apoptosis and diminished stemness properties via repression of RTCB in HNC-TICs.

The role of cooperativity in a p53-miR34 dynamical mathematical model

The objective of this study is to evaluate the role of cooperativity, captured by the Hill coefficient, in a minimal mathematical model describing the interactions between p53 and miR-34a. The model equations are analyzed for negative, none and normal cooperativity using a specific version of bifurcation theory and they are solved numerically. Special attention is paid to the sign of so-called first Lyapunov value. Interpretations of the results are given, both according to dynamic theory and in biological terms. In terms of cell signaling, we propose the hypothesis that when the outgoing signal of a system spends a physiologically significant amount of time outside of its equilibrium state, then the value of that signal can be sampled at any point along the trajectory towards that equilibrium and indeed, at multiple points. Coupled with non-linear behavior, such as that caused by cooperativity, this feature can account for a complex and varied response, which p53 is known for. From dynamical point of view, we found that when cooperativity is negative, the system has only one stable equilibrium point. In the absence of cooperativity, there is a single unstable equilibrium point with a critical boundary of stability. In the case with normal cooperativity, the system can have one, two, or three steady states with both, bi-stability and bi-instability occurring.

Cyclosporine A induces testicular injury via mitochondrial apoptotic pathway by regulation of mir-34a and sirt-1 in male rats: The rescue effect of curcumin

Testicular damage contributes to cyclosporine A (CsA) induced male infertility. However, the exact underlying molecular mediators involved in CsA-induced testis disorder remains unclear. The present study aimed to characterize the role of mir-34a/sirt-1 in CsA induced testicular injury alone or in combination with curcumin. A total of twenty-eight male Wistar rats were subdivided into four groups: control (Con), sham, cyclosporine A (CsA), cyclosporineA + curcumin (CsA + cur). The animals received cyclosporine A (30 mg/kg) and curcumin (40 mg/kg) for 28 days by oral gavage. At the end of the experiment, CsA administration significantly resulted in a decrease in testis weight and testis coefficient. The molecular analysis demonstrated that CsA exposure increased 8-OHdg and Nox4 protein contents in the testis tissue. TUNEL staining indicated that CsA caused the number of apoptotic cells to increase in the testes of male rats. In addition, exposure to CsA resulted in an increased expression of Bax, and a decreased expresion in that of Bcl-2, with a concomitant up-regulation of the Bax/Bcl-2, c-Caspase-3/p-Caspase-3 ratio and cytochrome c level. Meanwhile, exposure to CsA increased the expression of mir-34a and decreased sirt-1 protein level in the testis tissue samples compared to the control group. Taken together, our findings suggested that CsA can cause damage to testicular germ cells via oxidative stress and mitochondrial apoptotic pathway, and probably mir-34a/sirt-1 play a crucial role in this process. It also demonstrates that these negative effects of CsA can be reduced by using curcumin as an antioxidant and anti-inflammatory agent.

MicroRNAs signatures, bioinformatics analysis of miRNAs, miRNA mimics and antagonists, and miRNA therapeutics in osteosarcoma

MicroRNAs (miRNAs) involved in key signaling pathways and aggressive phenotypes of osteosarcoma (OS) was discussed, including PI3K/AKT/MTOR, MTOR AND RAF-1 signaling, tumor suppressor P53- linked miRNAs, NOTCH- related miRNAs, miRNA -15/16 cluster, apoptosis related miRNAs, invasion-metastasis-related miRNAs, and 14Q32-associated miRNAs cluster. Herrin, we discussed insights into the targeted therapies including miRNAs (i.e., tumor-suppressive miRNAs and oncomiRNAs). Using bioinformatics tools, the interaction network of all OS-associated miRNAs and their targets was also depicted.

Mir34a constrains pancreatic carcinogenesis

Several studies have shown that over 70 different microRNAs are aberrantly expressed in pancreatic ductal adenocarcinoma (PDAC), affecting proliferation, apoptosis, metabolism, EMT and metastasis. The most important genetic alterations driving PDAC are a constitutive active mutation of the oncogene Kras and loss of function of the tumour suppressor Tp53 gene. Since the MicroRNA 34a (Mir34a) is a direct target of Tp53 it may critically contribute to the suppression of PDAC. Mir34a is epigenetically silenced in numerous cancers, including PDAC, where Mir34a down-regulation has been associated with poor patient prognosis. To determine whether Mir34a represents a suppressor of PDAC formation we generated an in vivo PDAC-mouse model harbouring pancreas-specific loss of Mir34a (Kras^G12D; Mir34a^Δ/Δ). Histological analysis of Kras^G12D; Mir34a^Δ/Δ mice revealed an accelerated formation of pre-neoplastic lesions and a faster PDAC development, compared to Kras^G12D controls. Here we show that the accelerated phenotype is driven by an early up-regulation of the pro-inflammatory cytokines TNFA and IL6 in normal acinar cells and accompanied by the recruitment of immune cells. Our results imply that Mir34a restrains PDAC development by modulating the immune microenvironment of PDAC, thus defining Mir34a restauration as a potential therapeutic strategy for inhibition of PDAC development.

Insights about MYC and Apoptosis in B-Lymphomagenesis: An Update from Murine Models

The balance between cell survival and cell death represents an essential part of human tissue homeostasis, while altered apoptosis contributes to several pathologies and can affect the treatment efficacy. Impaired apoptosis is one of the main cancer hallmarks and some types of lymphomas harbor mutations that directly affect key regulators of cell death (such as BCL-2 family members). The development of novel techniques in the field of immunology and new animal models has greatly accelerated our understanding of oncogenic mechanisms in MYC-associated lymphomas. Mouse models are a powerful tool to reveal multiple genes implicated in the genesis of lymphoma and are extensively used to clarify the molecular mechanism of lymphoma, validating the gene function. Key features of MYC-induced apoptosis will be discussed here along with more recent studies on MYC direct and indirect interactors, including their cooperative action in lymphomagenesis. We review our current knowledge about the role of MYC-induced apoptosis in B-cell malignancies, discussing the transcriptional regulation network of MYC and regulatory feedback action of miRs during MYC-driven lymphomagenesis. More importantly, the finding of new modulators of apoptosis now enabling researchers to translate the discoveries that have been made in the laboratory into clinical practice to positively impact human health.

Dissecting miRNA facilitated physiology and function in human breast cancer for therapeutic intervention

MicroRNAs (miRNAs) are key epigenomic regulators of biological processes in animals and plants. These small non coding RNAs form a complex networks that regulate cellular function and development. MiRNAs prevent translation by either inactivation or inducing degradation of mRNA, a major concern in post-transcriptional gene regulation. Aberrant regulation of gene expression by miRNAs is frequently observed in cancer. Overexpression of various 'oncomiRs' and silencing of tumor suppressor miRNAs are associated with various types of human cancers, although overall downregulation of miRNA expression is reported as a hallmark of cancer. Modulations of the total pool of cellular miRNA by alteration in genetic and epigenetic factors associated with the biogenesis of miRNA machinery. It also depends on the availability of cellular miRNAs from its store in the organelles which affect tumor development and cancer progression. Here, we have dissected the roles and pathways of various miRNAs during normal cellular and molecular functions as well as during breast cancer progression. Recent research works and prevailing views implicate that there are two major types of miRNAs; (i) intracellular miRNAs and (ii) extracellular miRNAs. Concept, that the functions of intracellular miRNAs are driven by cellular organelles in mammalian cells. Extracellular miRNAs function in cell-cell communication in extracellular spaces and distance cells through circulation. A detailed understanding of organelle driven miRNA function and the precise role of extracellular miRNAs, pre- and post-therapeutic implications of miRNAs in this scenario would open several avenues for further understanding of miRNA function and can be better exploited for the treatment of breast cancers.

Oxidative stress-related miRNAs in spermatozoa may reveal the severity of damage in grade III varicocele

Varicocele is associated with excessive production of reactive oxygen species (ROS). Although the harmful effects of ROS on sperm DNA, proteins and lipids are well documented, its impact on the expression of miRNAs in spermatozoa has not been fully understood. In this study, the expression patterns of microRNAs (miRNAs), miR-21, miR-34a and miR-122a as well as the level of ROS in the fertile control (FC; proven fertility without varicocele, n = 15) and grade III varicocele patients with normal (VN; n = 15) and abnormal (VA; n = 15) spermogram were investigated. The real-time PCR was performed to analyse the expression of the miRNAs, while oxidative stress was evaluated by measuring the concentrations of MDA. Our results showed that the expression levels of miR-21 (p = .001), miR-34a, (p = .007) and miR-122a (p < .001) were significantly decreased in spermatozoa of VN and VA patients in comparison with the fertile group. Also, increased levels of oxidative stress were detected in semen samples of varicocele patients compared with the fertile control (p < .0001). Overall, these findings demonstrate oxidative stress changes the expression pattern of some miRNAs, and these alterations could be a valuable diagnostic marker for the diagnosis and prognosis of varicocele-induced oxidative stress to retain the male fertility during the spermatogenesis process.

microRNAs targeting cellular cholesterol: implications for combating anticancer drug resistance

Over sixty percent of all mammalian protein-coding genes are estimated to be regulated by microRNAs (miRNAs), and unsurprisingly miRNA dysregulation has been linked with cancer. Aberrant miRNA expression in cancer cells has been linked with tumourigenesis and drug resistance. In the past decade, increasing number of studies have demonstrated that cholesterol accumulation fuels tumour growth and contributes to drug resistance, therefore, miRNAs controlling cholesterol metabolism and homeostasis are obvious hypothetical targets for investigating their role in cholesterol-mediated drug resistance in cancer. In this review, we have collated published evidences to consolidate this hypothesis and have scrutinized it by utilizing computational tools to explore the role of miRNAs in cholesterol-mediated drug resistance in breast cancer cells. We found that hsa-miR-128 and hsa-miR-223 regulate genes mediating lipid signalling and cholesterol metabolism, cancer drug resistance and breast cancer genes. The analysis demonstrates that targeting these miRNAs in cancer cells presents an opportunity for developing new strategies to combat anticancer drug resistance.

miR-1262 Transcriptionally Modulated by an Enhancer Genetic Variant Improves Efficiency of Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors in Advanced Lung Adenocarcinoma

Advanced nonsmall-cell lung cancer (NSCLC) patients with mutated epidermal growth factor receptor (EGFR) can remarkably benefit from target therapy of EGFR-tyrosine kinase inhibitors (TKIs). However, increasing drug sensitivity and improving outcomes of NSCLC patients to EGFR-TKI therapy remains a challenge. Several studies have shown a link between microRNAs and drug resistance in cancer. In this study, we hypothesized that the rs12740674 single nucleotide polymorphism in the enhancer of miR-1262 may affect its expression, which may impact the outcome of NSCLC patients treated with EGFR-TKIs. The rs12740674 polymorphism was genotyped in two independent cohorts, including 319 EGFR-TKI treated stage IIIB/IV NSCLC patients. The allele-specific regulation on miR-1262 transcription by rs12740674 and impacts of miR-1262 on gefitinib sensitivity were evaluated in vitro and in vivo. Cox regression analyses indicated that the rs12740674 T allele was significantly associated with short survival time in both cohorts (p < 0.05). Luciferase assays demonstrated that the rs12740674 T allelic enhancer showed weaker capability to promote miR-1262 transcription compared with the C allelic enhancer, which may be due to reduced transcription factor binding according to electrophoretic mobility shift assays. Furthermore, significantly decreased miR-1262 expression in NSCLC and nontumor lung tissues of T allele carriers was observed compared with levels in C allele carriers. Moreover, miR-1262 expression enhanced the anticancer effects of gefitinib on NSCLC cells. Our data indicate that miR-1262 may be a potential therapeutic target for NSCLC.

Delivery of dual miRNA through CD44-targeted mesoporous silica nanoparticles for enhanced and effective triple-negative breast cancer therapy

The development of new therapeutic strategies to target triple-negative breast cancer (TNBC) is in much demand to overcome the roadblocks associated with the existing treatment procedures. In this regard, therapies targeting the CD44 receptor have drawn attention for more than a decade. MicroRNAs (miRNAs) modulate post-transcriptional gene regulation and thus, the correction of specific miRNA alterations using miRNA mimics or antagomiRs is an emerging strategy to normalize the genetic regulation in the tumor microenvironment. It has been acknowledged that miR-34a is downregulated and miR-10b is upregulated in TNBC, which promotes tumorigenesis and metastatic dissemination. However, there are a few barriers related to miRNA delivery. Herein, we have introduced tailored mesoporous silica nanoparticles (MSNs) for the co-delivery of miR-34a-mimic and antisense-miR-10b. MSN was functionalized with a cationic basic side chain and then loaded with the dual combination to overexpress miR-34a and downregulate miR-10b simultaneously. Finally, the loaded MSNs were coated with an hyaluronic acid-appended PEG-PLGA polymer for specific targeting. The cellular uptake, release profile, and subsequent effect in TNBC cells were evaluated. In vitro and in vivo studies demonstrated high specificity in TNBC tumor targeting, leading to efficient tumor growth inhibition as well as the retardation of metastasis, which affirmed the clinical application potential of the system.

The mechanistic, diagnostic and therapeutic novel nucleic acids for hepatocellular carcinoma emerging in past score years

Despite The Central Dogma states the destiny of gene as 'DNA makes RNA and RNA makes protein', the nucleic acids not only store and transmit genetic information but also, surprisingly, join in intracellular vital movement as a regulator of gene expression. Bioinformatics has contributed to knowledge for a series of emerging novel nucleic acids molecules. For typical cases, microRNA (miRNA), long noncoding RNA (lncRNA) and circular RNA (circRNA) exert crucial role in regulating vital biological processes, especially in malignant diseases. Due to extraordinarily heterogeneity among all malignancies, hepatocellular carcinoma (HCC) has emerged enormous limitation in diagnosis and therapy. Mechanistic, diagnostic and therapeutic nucleic acids for HCC emerging in past score years have been systematically reviewed. Particularly, we have organized recent advances on nucleic acids of HCC into three facets: (i) summarizing diverse nucleic acids and their modification (miRNA, lncRNA, circRNA, circulating tumor DNA and DNA methylation) acting as potential biomarkers in HCC diagnosis; (ii) concluding different patterns of three key noncoding RNAs (miRNA, lncRNA and circRNA) in gene regulation and (iii) outlining the progress of these novel nucleic acids for HCC diagnosis and therapy in clinical trials, and discuss their possibility for clinical applications. All in all, this review takes a detailed look at the advances of novel nucleic acids from potential of biomarkers and elaboration of mechanism to early clinical application in past 20 years.

MicroRNA-34a deficiency leads to impaired wound closure by augmented inflammation in mice

Background

Proper inflammation resolution is critical for cutaneous wound healing and disordered inflammation resolution results in chronic nonhealing wounds. However, the cellular and molecular mechanisms for resolution of inflammation during skin wound healing are not well understood. MicroRNA-34a is regarded as one tumor suppressor with complexed immune regulatory effects, yet its role during skin wound repair is still unclear.

Methods

Circular full thickness excisional wounds were made on the dorsal skin of C57 mice and miR-34a expression pattern was examined by real time RT-PCR and in situ hybridization. The wound healing rates and histologic morphometric analysis were quantified and compared between wounds treated with antagomir-34a and autologous control antagomir-NC wounds, as well as wounds between miR-34a knockout (KO) and wild type (WT) mice. Immunohistochemistry (IHC) for both MPO and F4/80 were performed to examine the infiltrative neutrophils and macrophages in wounds from miR-34a KO and WT mice. Cytokines including IL-1β, IL-6, TNF-α and IL-10, were detected and analyzed by real time RT-PCR during wound healing. IHC for IL-6 and p-STAT3 were quantified, and WB for p-STAT3 and IL-6R were examined in wounds of miR-34a KO and WT mice.

Results

We found miR-34a was significantly downregulated in the inflammatory phase and back to normal levels in the proliferative phase. Both topical knockdown wounds miR-34a levels by antagomir gel and systematic knockout miR-34a using KO mice resulted in impaired wound healing with delayed re-epithelialization and augmented inflammation. IHC results indicated that there were more residual infiltrative inflammatory cells in the proliferative phase. Moreover, over-activated IL-6/STAT3 signal pathway was identified in the wounds of miR-34a KO mice.

Conclusions

Our findings reveal that miR-34a deficiency augments skin wound inflammation response and leads to impaired wound healing, which suggest that targeted inhibition of miR-34a for tissue repair/regeneration should be with serious consideration.