MicroRNA-125b confers the resistance of breast cancer cells to paclitaxel through suppression of pro-apoptotic Bcl-2 antagonist killer 1 (Bak1) expression

Mutations in Necroptosis-Related Genes Reported in Breast Cancer: A Cosmic and Uniport Database-Based Study

Breast cancer (BC) now holds the top position as the primary reason of cancer-related fatalities worldwide, overtaking lung cancer. BC is classified into diverse categories depending on histopathological type, hormone receptor status, and gene expression profile, with ongoing evolution in their classifications. Cancer initiates and advances when there is a disruption in cell death pathways. In BC, the primary cell death pathway, apoptosis, experiences dysregulation across multiple stages. Ongoing studies aim to discover therapeutic targets that enhance cancer cell susceptibility to apoptosis. However, resistance to this therapy remains a significant challenge in treating BC. If apoptosis is hindered, investigating alternative pathways for cell death that can effectively eradicate BC cells during treatment becomes a valuable endeavor. In this context, necroptosis is gaining considerable focus as an alternative cell death pathway. Necroptosis represents a programmed version of necrosis which shares its key regulators with apoptosis. When apoptosis is hampered, necroptosis serves as an alternative cell death pathway even in physiological conditions like formation of limbs during embryonic development. Additionally, it comes into play during bacterial and viral infections when the apoptosis machinery is hijacked and inhibited by proteins from these pathogens. Studies reveal that in BC, mutations significantly impact molecules in the apoptosis pathway, contributing to the onset, advancement, and multiplication of cancer cells. Although some studies do indicate that the functionality of necroptosis pathway may be compromised in malignancy the status of its key molecules remains largely unknown. In this article, we aim to gather the known mutations present in key molecules of necroptosis among various subtypes of BC, utilizing data from the Cosmic and UniProt databases. The same may help to enhance the development of therapeutic strategies to effectively induce necroptosis in apoptosis-resistant BCs.

The role of miRNAs in pathogenesis, diagnosis, and therapy of Helicobacter pylori infection, gastric cancer-causing bacteria: Special highlights on nanotechnology-based therapy

Helicobacter pylori (H. pylori) infection and consequent inflammation in the stomach are widely recognized as major contributors to gastric cancer (GC) development. Recent investigations have placed considerable emphasis on uncovering the controlling influence of small RNA molecules known as microRNAs (miRNAs) in H. pylori-related diseases, particularly gastric cancer. This review aims to offer a comprehensive understanding of the intricate roles fulfilled by miRNAs in conditions associated with H. pylori infection. Exploring miRNA biogenesis pathways reveals their intimate connection with H. pylori infection, shedding light on the underlying molecular mechanisms driving disease progression and identifying potential intervention targets. An examination of epidemiological data surrounding H. pylori infection, including prevalence, risk factors, and transmission routes, underscores the imperative for preventive measures and targeted interventions. Incorporating insights from miRNA-related research into these strategies holds promise for enhancing their efficacy in controlling H. pylori spread. The symptoms, underlying mechanisms, and virulent characteristics of the bacteria highlight the intricate relationship between H. pylori and host cells, influencing the course of diseases. Within this complex web, miRNAs play pivotal roles, regulating various facets of H. pylori's development. MicroRNAs intricately involved in directing the immune response against H. pylori infection serve as key players in molding host defense mechanisms and impacting the bacterium's evasion tactics. Utilizing this knowledge holds the potential to drive forward groundbreaking therapeutic strategies. The diagnostic and prognostic capabilities of miRNAs in H. pylori infection highlight their effectiveness as non-invasive indicators for identifying diseases and evaluating risk. Integration of miRNA signatures into diagnostic algorithms holds promise for enhancing early detection and management of H. pylori-related diseases. MiRNA-based therapeutics offer a promising avenue for combatting H. pylori-induced gastric cancer, targeting specific molecular pathways implicated in tumorigenesis. H. pylori infection induces dysregulation of several miRNAs that contribute to antibiotic resistance, inflammation, and gastric cancer progression, including downregulation of tumor-suppressive miR-7 and miR-153 and upregulation of oncogenic miR-671-5p and miR-155-5p, which promote carcinogenesis and inflammation. Additionally, H. pylori manipulates host immune responses by upregulating miRNAs such as let-7f-5p, let-7i-5p, miR-146b-5p, and miR-185-5p that suppress HLA class II expression and antigen presentation, facilitating immune evasion and chronic gastritis that predispose to gastric cancer. Future research endeavors should focus on refining these therapeutic modalities and identifying novel targets to optimize clinical outcomes. By elucidating the multifaceted roles of miRNAs in H. pylori infection, this review provides invaluable insights into disease pathogenesis, diagnostics, and therapeutics, and the role of some nanoparticles in combating the H. pylori infection. Continued research efforts are imperative for translating these insights into clinical practice and addressing the global burden of H. pylori-related diseases.

tiRNA-HAR contributes to ischemic myocardial injury via facilitating HuR-mediated stability of p53

Cardiomyocyte death due to heart occlusion of coronary artery is the main driver to myocardial infarction (MI) and subsequent heart failure progression. tsRNA, a small RNA fragment from tRNA, has been shown to be implicated in many physiological and pathological processes by exerting different biological functions, but the roles of tsRNA in ischemic cardiac injury remain to be determined. The present study identified a hypoxia responsive-tiRNA (tiRNA-HAR) was markedly upregulated in ischemic mouse myocardium and hypoxic cardiomyocytes, respectively. Enforced expression of tiRNA-HAR by transfecting its mimic caused and aggravated, while knockdown of tiRNA-HAR mitigated cardiomyocyte apoptosis upon hypoxia. Cardiac specific knockdown of tiRNA-HAR mediated by AAV9 (adeno-associated virus 9) harboring an antisense oligonucleotide reduced cardiomyocytes apoptosis and improved cardiac function after MI. Mechanistically, tiRNA-HAR directly bound to HuR and enhanced the binding capacity of HuR and p53, thereby increasing the stability of p53. Silencing of HuR partially reversed the aggravative effects of tiRNA-HAR overexpression on cardiomyocyte apoptosis in the context of hypoxia. Collectively, our study reveals that tiRNA-HAR play a critical role in regulating cardiomyocytes apoptosis and cardiac injury via targeting HuR/p53 signaling axis after MI, and tiRNA-HAR might be a novel therapeutic target for treatment of ischemic heart disease.

PHD-2/HIF-1α axis mediates doxorubicin-induced angiogenesis in SH-SY5Y neuroblastoma microenvironment: a potential survival mechanism

The response of neuroblastoma (NB) cells to chemotherapeutics and their influence on NB microenvironment remain incompletely understood. Herein, we examined the underlying molecular mechanism via which Doxorubicin, a chemotherapeutic agent used for NB treatment, promotes proangiogenic response in the SH-SY5Y microenvironment. Doxorubicin treatment at 1 µg/ml reduced SH-SY5Y cell proliferation and primed the apoptosis pathway. Unexpectedly, SH-SY5Y cells treated with doxorubicin upregulated their expression of the pro-angiogenic factors, including vascular endothelial growth factor (VEGF), platelets-derived growth factor (PDGF), and matrix metalloprotease-2 (MMP-2) and secretion of nitric oxide. To assess the functional angiogenesis of SH-SY5Y cells pre-treated with doxorubicin, an indirect co-culture system with human umbilical vein endothelial cells (HUVEC) was established. These HUVECs acquired enhanced proliferation, migration capacity, and tube formation capability and exhibited increased nitric oxide (NO) production, in addition to upregulated α-smooth muscle actin expression, suggesting enhanced contractility. In-ovo studies of the neo-angiogenic response of SH-SY5Y pre-treated with doxorubicin further show their promoted neo-angiogenesis as indicated by the generated blood vessels and histological analysis of CD31 expression. Inhibition of PHD-2 could be a potential target for doxorubicin, as indicated by molecular docking, molecular dynamics (MD) simulation, and MM-GBSA calculations, leading to hypoxia-inducible factor-1 alpha (HIF-1α) stabilization. Bioinformatics analyses and enrichment analyses of RNA-seq data revealed activation of Pi3K pathway which is further validated in-vitro. These results provide evidence of the unexpected pro-angiogenic response of SH-SY5Y cells to doxorubicin treatment and suggest the potential use of multi-modal therapeutic regimens for a more comprehensive approach to NB treatment.

Lipid Nanovesicles in Cancer Treatment: Improving Targeting and Stability of Antisense Oligonucleotides

Cancer remains a leading cause of mortality worldwide, accounting for approximately 10 million deaths annually. Standard treatments, including surgery, radiotherapy, and chemotherapy, often result in damage to healthy cells and severe toxic side effects. In recent years, antisense technology therapeutics, which interfere with RNA translation through complementary base pairing, have emerged as promising approaches for cancer treatment. Despite the availability of various antisense oligonucleotide (ASO) drugs on the market, challenges such as poor active targeting and susceptibility to clearance by circulating enzymes remain. Compared with other delivery systems, lipid nanovesicle (LNV) delivery systems offer a potential solution that uniquely enhances ASO targeting and stability. Studies have shown that LNVs can increase the accumulation of ASOs in tumor sites several-fold, significantly reducing systemic toxic reactions and demonstrating increased therapeutic efficiency in preclinical models. Additionally, LNVs can protect ASOs from enzymatic degradation within the body, extending their half-life and thus enhancing their therapeutic effects. This paper provides a comprehensive review of recent examples and applications of LNV delivery of ASOs in cancer treatment, highlighting their unique functions and outcomes. Furthermore, this paper discusses the key challenges and potential impacts of this innovative approach to cancer therapy.

ANXA5 predicts prognosis and immune response and mediates proliferation and migration in head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a common malignancy that often develops unnoticed. Typically, these tumors are identified at advanced stages, resulting in a relatively low chance of successful treatment. Anoikis serves as a natural defense against the spread of tumor cells, meaning circumventing anoikis can effectively inhibit tumor metastasis. Nonetheless, studies focusing on anoikis in the context of HNSCC remain scarce.

METHODS

Anoikis-related genes (ARGs) were identified by using the GeneCards and Harmonizome databases. Expression data of these genes and relevant clinical features were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. A LASSO regression and a prognostic risk score model were developed to determine their prognostic significance. The analysis included the use of the CIBERSORT algorithm to quantify immune and stromal cell presence. Furthermore, in vitro and in vivo, we confirmed the expression and functional roles of proteins and mRNA of genes independently predictive of prognosis.

RESULTS

The study identified eight genes linked to prognosis (ANXA5, BAK1, CDKN2A, PPARG, CCR7, MAPK11, CRYAB, CRYBA1) and developed a prognostic model that effectively forecasts the survival outcomes for patients with HNSCC. A higher survival likelihood is associated with lower risk scores. In addition, a significant relationship was found between immune and risk score, and ANXA5 deletion promoted the killing of HNSCC cells by activated CD8+ T cells. During the screening process, 65 different chemotherapeutic drugs were found to have significant differences in IC50 values when comparing high- and low-risk categories. ANXA5 emerged as a gene with independent prognostic significance, exhibiting notably elevated protein and mRNA levels in HNSCC tissue compared to non-tumorous tissue. The suppression of ANXA5 gene activity resulted in a substantial decrease in both the growth and mobility of HNSCC cells. Animal model experiments demonstrated that inhibiting ANXA5 suppressed HNSCC growth and migration in vivo.

CONCLUSION

Through bioinformatics, a prognostic risk model of high precision was developed, offering valuable insights into the survival rates and immune responses in patients with HNSCC. ANXA5 is highlighted as a significant prognostic factor among the identified genes, indicating its promise as a potential therapeutic target for those with HNSCC.

Use of Gain-of-Function Screening to Identify miRNAs Involved in Paclitaxel Resistance in Triple-Negative Breast Cancer

Paclitaxel is a widely used chemotherapeutic agent for the treatment of breast cancer (BC), including as a front-line treatment for triple-negative breast cancer (TNBC) patients. However, resistance to paclitaxel remains one of the major causes of death associated with treatment failure. Multiple studies have demonstrated that miRNAs play a role in paclitaxel resistance and are associated with both disease progression and metastasis. In the present study, we used a miRNA-encoding lentiviral library as a gain-of-function screen for paclitaxel resistance in the MDA-MB-231 TNBC cell line. We identified that miR-181b, miR-29a, miR-30c, miR-196 and miR-1295 conferred a resistant phenotype to cells. The expression of miR-29a also induced resistance to eribulin and vinorelbine, while miR-181b and miR-30c induced resistance to vinorelbine. We measured the levels of these miRNAs in breast cancer patients and observed higher levels of miR-29a in treatment-refractory patients. Taken together, we suggest that miR-29a and miR-181b may be good candidates for miRNA inhibition to overcome resistance to chemotherapy.

Dual role of microRNA-31 in human cancers; focusing on cancer pathogenesis and signaling pathways

Widespread changes in the expression of microRNAs in cancer result in abnormal gene expression for the miRNAs that control those genes, which in turn causes changes to entire molecular networks and pathways. The frequently altered miR-31, which is found in a wide range of cancers, is one cancer-related miRNA that is particularly intriguing. MiR-31 has a very complicated set of biological functions, and depending on the type of tumor, it may act both as a tumor suppressor and an oncogene. The endogenous expression levels of miR-31 appear to be a key determinant of the phenotype brought on by aberrant expression. Varied expression levels of miR-31 could affect cell growth, metastasis, drug resistance, and other process by several mechanisms like targeting BRCA1-associated protein-1 (BAP1), large tumor suppressor kinase 1 (LATS1) and protein phosphatase 2 (PP2A). This review highlights the current understanding of the genes that miR-31 targets while summarizing the complex expression patterns of miR-31 in human cancers and the diverse phenotypes brought on by altered miR-31 expression.

Multi-omic lineage tracing predicts the transcriptional, epigenetic and genetic determinants of cancer evolution

Cancer is a highly heterogeneous disease, where phenotypically distinct subpopulations coexist and can be primed to different fates. Both genetic and epigenetic factors may drive cancer evolution, however little is known about whether and how such a process is pre-encoded in cancer clones. Using single-cell multi-omic lineage tracing and phenotypic assays, we investigate the predictive features of either tumour initiation or drug tolerance within the same cancer population. Clones primed to tumour initiation in vivo display two distinct transcriptional states at baseline. Remarkably, these states share a distinctive DNA accessibility profile, highlighting an epigenetic basis for tumour initiation. The drug tolerant niche is also largely pre-encoded, but only partially overlaps the tumour-initiating one and evolves following two genetically and transcriptionally distinct trajectories. Our study highlights coexisting genetic, epigenetic and transcriptional determinants of cancer evolution, unravelling the molecular complexity of pre-encoded tumour phenotypes.

Exploring miRNA‑target gene profiles associated with drug resistance in patients with breast cancer receiving neoadjuvant chemotherapy

Exosomal microRNAs (miRNAs) are closely related to drug resistance in patients with breast cancer (BC); however, only a few roles of the exosomal miRNA-target gene networks have been clinically implicated in drug resistance in BC. Therefore, the present study aimed to identify the differential expression of exosomal miRNAs associated with drug resistance and their target mRNAs. In vitro microarray analysis was used to verify differentially expressed miRNAs (DEMs) in drug-resistant BC. Next, tumor-derived exosomes (TDEs) were isolated. Furthermore, it was determined whether the candidate drug-resistant miRNAs were also significant in TDEs, and then putative miRNAs in TDEs were validated in plasma samples from 35 patients with BC (20 patients with BC showing no response and 15 patients with BC showing a complete response). It was confirmed that the combination of five exosomal miRNAs, including miR-125b-5p, miR-146a-5p, miR-484, miR-1246-5p and miR-1260b, was effective for predicting therapeutic response to neoadjuvant chemotherapy, with an area under the curve value of 0.95, sensitivity of 75%, and specificity of 95%. Public datasets were analyzed to identify differentially expressed genes (DEGs) related to drug resistance and it was revealed that BAK1, NOVA1, PTGER4, RTKN2, AGO1, CAP1, and ETS1 were the target genes of exosomal miRNAs. Networks between DEMs and DEGs were highly correlated with mitosis, metabolism, drug transport, and immune responses. Consequently, these targets could be used as predictive markers and therapeutic targets for clinical applications to enhance treatment outcomes for patients with BC.

Decoding contextual crosstalk: revealing distinct interactions between non-coding RNAs and unfolded protein response in breast cancer

Breast cancer is significantly influenced by endoplasmic reticulum (ER) stress, impacting both its initiation and progression. When cells experience an accumulation of misfolded or unfolded proteins, they activate the unfolded protein response (UPR) to restore cellular balance. In breast cancer, the UPR is frequently triggered due to challenging conditions within tumors. The UPR has a dual impact on breast cancer. On one hand, it can contribute to tumor growth by enhancing cell survival and resistance to programmed cell death in unfavorable environments. On the other hand, prolonged and severe ER stress can trigger cell death mechanisms, limiting tumor progression. Furthermore, ER stress has been linked to the regulation of non-coding RNAs (ncRNAs) in breast cancer cells. These ncRNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), play essential roles in cancer development by influencing gene expression and cellular processes. An improved understanding of how ER stress and ncRNAs interact in breast cancer can potentially lead to new treatment approaches. Modifying specific ncRNAs involved in the ER stress response might interfere with cancer cell survival and induce cell death. Additionally, focusing on UPR-associated proteins that interact with ncRNAs could offer novel therapeutic possibilities. Therefore, this review provides a concise overview of the interconnection between ER stress and ncRNAs in breast cancer, elucidating the nuanced effects of the UPR on cell fate and emphasizing the regulatory roles of ncRNAs in breast cancer progression.

Effects of Eribulin on the RNA Content of Extracellular Vesicles Released by Metastatic Breast Cancer Cells

Extracellular vesicles (EVs) are small lipid particles secreted by almost all human cells into the extracellular space. They perform the essential function of cell-to-cell communication, and their role in promoting breast cancer progression has been well demonstrated. It is known that EVs released by triple-negative and highly aggressive MDA-MB-231 breast cancer cells treated with paclitaxel, a microtubule-targeting agent (MTA), promoted chemoresistance in EV-recipient cells. Here, we studied the RNA content of EVs produced by the same MDA-MB-231 breast cancer cells treated with another MTA, eribulin mesylate. In particular, we analyzed the expression of different RNA species, including mRNAs, lncRNAs, miRNAs, snoRNAs, piRNAs and tRNA fragments by RNA-seq. Then, we performed differential expression analysis, weighted gene co-expression network analysis (WGCNA), functional enrichment analysis, and miRNA-target identification. Our findings demonstrate the possible involvement of EVs from eribulin-treated cells in the spread of chemoresistance, prompting the design of strategies that selectively target tumor EVs.

Dysregulation of different modes of programmed cell death by epigenetic modifications and their role in cancer

Modifications of epigenetic factors affect our lives and can give important information regarding one's state of health. In cancer, epigenetic modifications play a crucial role, as they influence various programmed cell death types. The purpose of this review is to investigate how epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNAs, influence various cell death processes in suppressing or promoting cancer development. Autophagy and apoptosis are the most investigated programmed cell death modes, as based on the tumor stage these cell death types can either promote or prevent cancer evolution. Therefore, our discussion focuses on how epigenetic modifications affect autophagy and apoptosis, as well as their diagnostic and therapeutical potential in combination with available chemotherapeutics. Additionally, we summarize the available data regarding the role of epigenetic modifications on other programmed cell death modes, such as ferroptosis, necroptosis, and parthanatos in cancer and discuss current advancements.

miR-125 in Breast Cancer Etiopathogenesis: An Emerging Role as a Biomarker in Differential Diagnosis, Regenerative Medicine, and the Challenges of Personalized Medicine

Breast Cancer (BC) is one of the most common cancer types worldwide, and it is characterized by a complex etiopathogenesis, resulting in an equally complex classification of subtypes. MicroRNA (miRNA or miR) are small non-coding RNA molecules that have an essential role in gene expression and are significantly linked to tumor development and angiogenesis in different types of cancer. Recently, complex interactions among coding and non-coding RNA have been elucidated, further shedding light on the complexity of the roles these molecules fulfill in cancer formation. In this context, knowledge about the role of miR in BC has significantly improved, highlighting the deregulation of these molecules as additional factors influencing BC occurrence, development and classification. A considerable number of papers has been published over the past few years regarding the role of miR-125 in human pathology in general and in several types of cancer formation in particular. Interestingly, miR-125 family members have been recently linked to BC formation as well, and complex interactions (competing endogenous RNA networks, or ceRNET) between this molecule and target mRNA have been described. In this review, we summarize the state-of-the-art about research on this topic.

Dynamic altruistic cooperation within breast tumors

BACKGROUND

Social behaviors such as altruism, where one self-sacrifices for collective benefits, critically influence an organism's survival and responses to the environment. Such behaviors are widely exemplified in nature but have been underexplored in cancer cells which are conventionally seen as selfish competitive players. This multidisciplinary study explores altruism and its mechanism in breast cancer cells and its contribution to chemoresistance.

METHODS

MicroRNA profiling was performed on circulating tumor cells collected from the blood of treated breast cancer patients. Cancer cell lines ectopically expressing candidate miRNA were used in co-culture experiments and treated with docetaxel. Ecological parameters like relative survival and relative fitness were assessed using flow cytometry. Functional studies and characterization performed in vitro and in vivo include proliferation, iTRAQ-mass spectrometry, RNA sequencing, inhibition by small molecules and antibodies, siRNA knockdown, CRISPR/dCas9 inhibition and fluorescence imaging of promoter reporter-expressing cells. Mathematical modeling based on evolutionary game theory was performed to simulate spatial organization of cancer cells.

RESULTS

Opposing cancer processes underlie altruism: an oncogenic process involving secretion of IGFBP2 and CCL28 by the altruists to induce survival benefits in neighboring cells under taxane exposure, and a self-sacrificial tumor suppressive process impeding proliferation of altruists via cell cycle arrest. Both processes are regulated concurrently in the altruists by miR-125b, via differential NF-κB signaling specifically through IKKβ. Altruistic cells persist in the tumor despite their self-sacrifice, as they can regenerate epigenetically from non-altruists via a KLF2/PCAF-mediated mechanism. The altruists maintain a sparse spatial organization by inhibiting surrounding cells from adopting the altruistic fate via a lateral inhibition mechanism involving a GAB1-PI3K-AKT-miR-125b signaling circuit.

CONCLUSIONS

Our data reveal molecular mechanisms underlying manifestation, persistence and spatial spread of cancer cell altruism. A minor population behave altruistically at a cost to itself producing a collective benefit for the tumor, suggesting tumors to be dynamic social systems governed by the same rules of cooperation in social organisms. Understanding cancer cell altruism may lead to more holistic models of tumor evolution and drug response, as well as therapeutic paradigms that account for social interactions. Cancer cells constitute tractable experimental models for fields beyond oncology, like evolutionary ecology and game theory.

ncRNAs: an unexplored cellular defense mechanism in leprosy

Leprosy is an infectious disease primarily caused by the obligate intracellular parasite Mycobacterium leprae. Although it has been considered eradicated in many countries, leprosy continues to be a health issue in developing nations. Besides the social stigma associated with it, individuals affected by leprosy may experience nerve damage leading to physical disabilities if the disease is not properly treated or early diagnosed. Leprosy is recognized as a complex disease wherein socioenvironmental factors, immune response, and host genetics interact to contribute to its development. Recently, a new field of study called epigenetics has emerged, revealing that the immune response and other mechanisms related to infectious diseases can be influenced by noncoding RNAs. This review aims to summarize the significant advancements concerning non-coding RNAs in leprosy, discussing the key perspectives on this novel approach to comprehending the pathophysiology of the disease and identifying molecular markers. In our view, investigations on non-coding RNAs in leprosy hold promise and warrant increased attention from researches in this field.

miRNAs in the prognosis of triple-negative breast cancer: A review

Triple-Negative Breast Cancer (TNBC) is a highly aggressive and invasive type of breast cancer (BC) with high mortality rate wherein effective target medicaments are lacking. It is a very heterogeneous group with several subtypes that account for 10-20% of cancer among women globally, being negative for three most important receptors (estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2)), with an early and high recurrence resulting in poor survival rate. Therefore, a more thorough knowledge on carcinogenesis of TNBC is required for the development of personalized treatment options. miRNAs can either promote or suppress tumorigenesis and have been linked to a number of features of cancer progression, including proliferation, metastasis, apoptosis, and epithelial-mesenchymal transition (EMT). Recent miRNA research shows that there is great potential for the development of novel biomarkers as they have emerged as drivers of tumorigenesis and provide opportunities to target various components involved in TNBC, thus helping to solve this difficult-to-treat disease. In this review, we summarize the most relevant miRNAs that play an essential role in TNBC biology. Their role with regard to molecular mechanisms underlying TNBC progression has been discussed, and their potential use as therapeutic or prognostic markers to unravel the intricacy of TNBC based on the pieces of evidence obtained from various works of literature has been briefly addressed.

miRNA-214-3p stimulates carcinogen-induced mammary epithelial cell apoptosis in mammary cancer-resistant species

Mammary cancer incidence varies greatly across species and underlying mechanisms remain elusive. We previously showed that mammosphere-derived epithelial cells from species with low mammary cancer incidence, such as horses, respond to carcinogen 7, 12-Dimethylbenz(a)anthracene-induced DNA damage by undergoing apoptosis, a postulated anti-cancer mechanism. Additionally, we found that miR-214-3p expression in mammosphere-derived epithelial cells is lower in mammary cancer-resistant as compared to mammary cancer-susceptible species. Here we show that increasing miR-214 expression and decreasing expression of its target gene nuclear factor kappa B subunit 1 in mammosphere-derived epithelial cells from horses abolishes 7,12-Dimethylbenz(a)anthracene-induced apoptosis. A direct interaction of miR-214-3p with another target gene, unc-5 netrin receptor A, is also demonstrated. We propose that relatively low levels of miR-214 in mammosphere-derived epithelial cells from mammals with low mammary cancer incidence, allow for constitutive gene nuclear factor kappa B subunit 1 expression and apoptosis in response to 7, 12-Dimethylbenz(a)anthracene. Better understanding of the mechanisms regulating cellular responses to carcinogens improves our overall understanding of mammary cancer resistance mechanisms.

Resistance of breast cancer cells to paclitaxel is associated with low expressions of miRNA-186 and miRNA-7

Aim: Neo-adjuvant chemotherapy is a common approach for the complex treatment of breast cancer (BC) and paclitaxel (PTX) is frequently included in the therapeutic regimen. However, the effect of PTX-based treatment is hard to predict precisely based on routinely used markers. As microRNAs are considered a new promising class of biomarkers, the link between miRNA expression and PTX resistance of BC cells needs to be well investigated. This study aimed at the identification of miRNAs associated with responses of BC cells to PTX. Methods: Intrinsic PTX sensitivity and miRNA profiling were assayed in five BC cell lines to identify candidate miRNAs. Selected miRNA (n. 15) expressions were analyzed by real-time-quantitative polymerase chain reaction (RT-qPCR) in BC tissue samples (n. 31) obtained from a diagnostic biopsy. Results were analyzed in the context of the effect of two cycles of PTX and the effect of the completed scheme of neoadjuvant therapy. The study's design facilitated the evaluation of the effect of PTX on cells and the identification of features of the microRNA expression profiles associated exclusively with sensitivity to this drug. Results: miR-186 and miR-7 expression in BC tissues was higher in patients with better outcomes of PTX-based neoadjuvant therapy. Conclusion: High expressions of miR-186 and miR-7 are associated with good response to PTX, whereas their low expressions may be associated with resistance to PTX in BC, indicating the possibility of developing innovative test systems for the prediction of the PTX response, which can be used before the start of neo-adjuvant chemotherapy for BC.

Cancer chemoresistance and its mechanisms: Associated molecular factors and its regulatory role

Cancer therapy has advanced from tradition chemotherapy methods to targeted therapy, novel drug delivery mechanisms, combination therapies etc. Although several novel chemotherapy strategies have been introduced, chemoresistance still remains as one of the major barriers in cancer treatments. Chemoresistance can lead to relapse and hinder the development of improved clinical results for cancer patients, and this continues to be the major hurdle in cancer therapy. Anticancer drugs acquire chemoresistance through different mechanisms. Understanding these mechanisms is crucial to overcome and increase the efficiency of the cancer therapies that are employed. The potential molecular pathways behind chemoresistance include tumor heterogeneity, elevated drug efflux, multidrug resistance, interconnected signaling pathways, and other factors. To surpass this limitation, new clinical tactics are to be introduced. This review aims to compile the most recent information on the molecular pathways that regulate chemoresistance in cancers, which will aid in development of new therapeutic targets and strategies.

miRNAs orchestration of gallbladder cancer - Particular emphasis on diagnosis, progression and drug resistance

Gallbladder cancer (GBC) is characterized by a highly invasive nature and a poor prognosis, with adenocarcinoma being the main histological subtype. According to statistical data, patients diagnosed with advanced GBC have a survival rate of less than 5% for 5 years. Despite the novel therapeutic techniques, the unsatisfactory results could be related to the underlying biology of tumor cells and resistance to chemotherapy. Early diagnosis is more important than clinical therapy as it assists in determining the pathological stage of cancer and facilitates the selection of appropriate medication. Hence, it is very important to understand the precise pathogenesis of GBC and to discover potential novel biomarkers for early diagnosis of GBC. Non-coding RNAs, such as microRNAs, long non-coding RNAs, and circular RNAs, have been found to influence the transcriptional regulation of target genes associated with cancer, either directly or indirectly. microRNAs are a group of small, non-coding, single-stranded RNAs that are expressed endogenously. miRNAs play significant roles in various fundamental cellular processes. Therefore, miRNAs have the potential to serve as valuable biomarkers and therapeutic targets for GBC.

Exosome-mediated miR-144-3p promotes ferroptosis to inhibit osteosarcoma proliferation, migration, and invasion through regulating ZEB1

BACKGROUND

Osteosarcoma (OS) is the most prevalent orthopedic malignancy with a dismal prognosis. The high iron absorption rate in OS cells of patients suggests that ferroptosis may be related to the progression of OS, but its potential molecular regulatory role is still unclear. Based on the ability to couple with exosomes for targeted delivery of signals, exosome-derived micro ribonucleic acids (miRNAs) can potentially serve as diagnostic biomarkers for OS.

METHODS

We identified ferroptosis-related miRNAs and messenger ribonucleic acids(mRNAs) in OS using bioinformatics analysis and performed survival analysis. Then we measured miRNA expression levels through exosome microarray sequencing, and used RT-qPCR and IHC to verify the expression level of miR-144-3p and ZEB1. Stable gene expression cell lines were fabricated for in vitro experiments. Cell viability, migration and invasion were determined by CCK-8 and transwell experiment. Use the corresponding reagent kit to detect GSH/GSSG ratio, Fe²⁺ level, MDA level and ROS level, and measure the expression levels of GPX4, ACSL4 and xCT through RT-qPCR and WB. We also constructed nude mice model for in vivo experiments. Finally, the stability of the miRNA/mRNA axis was verified through functional rescue experiments.

RESULTS

Low expression of miR-144-3p and high expression of ZEB1 in OS cell lines and tissues was observed. Overexpression of miR-144-3p can promote ferroptosis, reduce the survival ability of OS cells, and prevent the progression of OS. In addition, overexpression of miR-144-3p can downregulate the expression of ZEB1 in cell lines and nude mice. Knockdown of miR-144-3p has the opposite effect. The functional rescue experiment validated that miR-144-3p can regulate downstream ZEB1, and participates in the occurrence and development of OS by interfering with redox homeostasis and iron metabolism.

CONCLUSIONS

MiR-144-3p can induce the occurrence of ferroptosis by negatively regulating the expression of ZEB1, thereby inhibiting the proliferation, migration, and invasion of OS cells.

Roles of non-coding RNAs in cell death pathways involved in the treatment of resistance and recurrence of cancer

Considering the burden of cancer, a number of methods have been applied to control or stop it. However, because of drug resistance or cancer recurrence, these treatments usually face failure. Combination of modulation of expression of non-coding RNAs (ncRNAs) with other treatments can increase treatment-sensitivity of tumors but these approaches still face some challenges. Gathering information in this field is a prerequisite to find more efficient cures for cancer. Cancer cells use ncRNAs to enhance uncontrolled proliferation originated from inactivation of cell death routs. In this review article, the main routes of cell death and involved ncRNAs in these routes are discussed. Moreover, extant information in the role of different ncRNAs on cell death pathways involved in the treatment resistance and cancer recurrence is summarized.

Landscape of NcRNAs involved in drug resistance of breast cancer

Breast cancer (BC) leads to the most amounts of deaths among women. Chemo-, endocrine-, and targeted therapies are the mainstay drug treatments for BC in the clinic. However, drug resistance is a major obstacle for BC patients, and it leads to poor prognosis. Accumulating evidences suggested that noncoding RNAs (ncRNAs) are intricately linked to a wide range of pathological processes, including drug resistance. Till date, the correlation between drug resistance and ncRNAs is not completely understood in BC. Herein, we comprehensively summarized a dysregulated ncRNAs landscape that promotes or inhibits drug resistance in chemo-, endocrine-, and targeted BC therapies. Our review will pave way for the effective management of drug resistance by targeting oncogenic ncRNAs, which, in turn will promote drug sensitivity of BC in the future.

Breast cancer: miRNAs monitoring chemoresistance and systemic therapy

With a high mortality rate that accounts for millions of cancer-related deaths each year, breast cancer is the second most common malignancy in women. Chemotherapy has significant potential in the prevention and spreading of breast cancer; however, drug resistance often hinders therapy in breast cancer patients. The identification and the use of novel molecular biomarkers, which can predict response to chemotherapy, might lead to tailoring breast cancer treatment. In this context, accumulating research has reported microRNAs (miRNAs) as potential biomarkers for early cancer detection, and are conducive to designing a more specific treatment plan by helping analyze drug resistance and sensitivity in breast cancer treatment. In this review, miRNAs are discussed in two alternative ways-as tumor suppressors to be used in miRNA replacement therapy to reduce oncogenesis and as oncomirs to lessen the translation of the target miRNA. Different miRNAs like miR-638, miR-17, miR-20b, miR-342, miR-484, miR-21, miR-24, miR-27, miR-23 and miR-200 are involved in the regulation of chemoresistance through diverse genetic targets. For instance, tumor-suppressing miRNAs like miR-342, miR-16, miR-214, and miR-128 and tumor-promoting miRNAs like miR101 and miR-106-25 cluster regulate the cell cycle, apoptosis, epithelial to mesenchymal transition and other pathways to impart breast cancer drug resistance. Hence, in this review, we have discussed the significance of miRNA biomarkers that could assist in providing novel therapeutic targets to overcome potential chemotherapy resistance to systemic therapy and further facilitate the design of tailored therapy for enhanced efficacy against breast cancer.

MiR-145 inhibits cell migration and increases paclitaxel chemosensitivity in prostate cancer cells

Objectives

Prostate cancer (PC) is one of the most commonly diagnosed malignancies among men worldwide. Paclitaxel is a chemotherapeutic agent widely used to treat different types of cancer. Recent studies revealed miRNAs control various genes that influence the regulation of many biological and pathological processes such as the formation and development of cancer, chemotherapy resistance, etc.

Materials and Methods

Between three PC cell lines (PC3, DU-145, LNCAP), PC3 showed the lowest miR-145 expression and was chosen for experiments. PC3 cells were treated with paclitaxel and miR-145 separately or in combination. To measure the cell viability, migratory capacity, autophagy, cell cycle progression, and apoptosis induction, the MTT assay, wound-healing assay, and Annexin V/PI apoptosis assay were used, respectively. Moreover, quantitative real-time PCR (qRT-PCR) was employed to measure the expression level of genes involved in apoptosis, migration, and stemness properties.

Results

Obtained results illustrated that miR-145 transfection could enhance the sensitivity of PC3 cells to paclitaxel and increase paclitaxel-induced apoptosis by modulating the expression of related genes, including Caspase-3, Caspase-9, Bax, and Bcl-2. Also, results showed combination therapy increased cell cycle arrest at the sub-G1 phase. miR-145 and paclitaxel cooperatively reduced migration ability and related-metastatic and stemness gene expression, including MMP-2, MMP-9, CD44, and SOX-2. In addition, combination therapy can suppress MDR1 expression.

Conclusion

These results confirmed that miR-145 combined with paclitaxel cooperatively could inhibit cell proliferation and migration and increase the chemosensitivity of PC3 cells compared to mono treatment. So, miR-145 combination therapy may be used as a promising approach for PC treatment.

MicroRNA-dependent mechanisms of taxane resistance in breast cancer

Breast cancer (BC) has a leading position in the statistics of oncological morbidity and mortality among women. Taxan-based polychemotherapy regimens are an essential component of the complex therapy of the BC. However, currently used algorithms of taxan-based regimens application do not always provide with desire effect. It indicates the need to identify new prognostic markers and to develop new approaches to modify response of BC cells to standard therapeutic regimens. MicroRNAs, small RNA molecules regulating protein synthesis, are considered as promising markers and potential modulators of the BC cells sensitivity to taxanes.

The review includes a brief summary of the molecular mechanisms of action of the taxanes and the mechanism BC resistance to the process of microtubules depolymerization, provides with analysis of recent experimental and observational studies of the role of microRNAs in control of these mechanisms, and evaluates prospects for the development of new approaches to predict and to improve the cytostatic effects of taxanes through the analysis and modification of cellular microRNAs.

Advancements in Polymeric Nanocarriers to Mediate Targeted Therapy against Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a destructive disease with a poor prognosis, low survival rate and high rate of metastasis. It comprises 15% of total breast cancers and is marked by deficiency of three important receptor expressions, i.e., progesterone, estrogen, and human epidermal growth factor receptors. This absence of receptors is the foremost cause of current TNBC therapy failure, resulting in poor therapeutic response in patients. Polymeric nanoparticles are gaining much popularity for transporting chemotherapeutics, genes, and small-interfering RNAs. Due to their exclusive properties such as great stability, easy surface modification, stimuli-responsive and controlled drug release, ability to condense more than one therapeutic moiety inside, tumor-specific delivery of payload, enhanced permeation and retention effect, present them as ideal nanocarriers for increasing efficacy, bioavailability and reducing the toxicity of therapeutic agents. They can even be used as theragnostic agents for the diagnosis of TNBC along with its treatment. In this review, we discuss the limitations of already existing TNBC therapies and highlight the novel approach to designing and the functionalization of polymeric nanocarriers for the effective treatment of TNBC.

microRNAs associated with the pathogenesis and their role in regulating various signaling pathways during Mycobacterium tuberculosis infection

Despite more than a decade of active study, tuberculosis (TB) remains a serious health concern across the world, and it is still the biggest cause of mortality in the human population. Pathogenic bacteria recognize host-induced responses and adapt to those hostile circumstances. This high level of adaptability necessitates a strong regulation of bacterial metabolic characteristics. Furthermore, the immune reponse of the host virulence factors such as host invasion, colonization, and survival must be properly coordinated by the pathogen. This can only be accomplished by close synchronization of gene expression. Understanding the molecular characteristics of mycobacterial pathogenesis in order to discover therapies that prevent or resolve illness relies on the bacterial capacity to adjust its metabolism and replication in response to various environmental cues as necessary. An extensive literature details the transcriptional alterations of host in response to in vitro environmental stressors, macrophage infection, and human illness. Various studies have recently revealed the finding of several microRNAs (miRNAs) that are believed to play an important role in the regulatory networks responsible for adaptability and virulence in Mycobacterium tuberculosis. We highlighted the growing data on the existence and quantity of several forms of miRNAs in the pathogenesis of M. tuberculosis, considered their possible relevance to disease etiology, and discussed how the miRNA-based signaling pathways regulate bacterial virulence factors.

A new biomarker to enhance the radiosensitivity of hepatocellular cancer: miRNAs

Aims: This review summarizes findings regarding miRNAs that modulate radiation in hepatocellular carcinoma (HCC) and evaluates their potential clinical therapeutic uses. Materials & methods: We searched the relevant English-language medical databases for papers on miRNAs and radiation therapy for tumors to identify miRNAs that are linked with radiosensitivity and radioresistance, focusing on those associated with HCC radiation. Results: There were 88 papers assessed for miRNAs associated with tumor radiation, 56 of which dealt with radiosensitization, 21 with radioresistance and 11 with radiosensitization for HCC. Conclusion: Further work in this area would enable future evaluation of radiation responses and the potential use of miRNAs as therapeutic agents in HCC patients.

Epigenetic and breast cancer therapy: Promising diagnostic and therapeutic applications

The global burden of breast cancer (BC) is increasing significantly. This trend is caused by several factors such as late diagnosis, limited treatment options for certain BC subtypes, drug resistance which all lead to poor clinical outcomes. Recent research has reported the role of epigenetic alterations in the mechanism of BC pathogenesis and its hallmarks include drug resistance and stemness features. The understanding of these modifications and their significance in the management of BC carcinogenesis is challenging and requires further attention. Nevertheless, it promises to provide novel insight needed for utilizing these alterations as potential diagnostic, prognostic markers, predict treatment efficacy, as well as therapeutic agents. This highlights the importance of continuing research development to further advance the existing knowledge on epigenetics and BC carcinogenesis to overcome the current challenges. Hence, this review aims to shed light and discuss the current state of epigenetics research in the diagnosis and management of BC.

Mechanisms of cancer cell death induction by paclitaxel: an updated review

Chemoresistance of cancer cells is a major problem in treating cancer. Knowledge of how cancer cells may die or resist cancer drugs is critical to providing certain strategies to overcome tumour resistance to treatment. Paclitaxel is known as a chemotherapy drug that can suppress the proliferation of cancer cells by inducing cell cycle arrest and induction of mitotic catastrophe. However, today, it is well known that paclitaxel can induce multiple kinds of cell death in cancers. Besides the induction of mitotic catastrophe that occurs during mitosis, paclitaxel has been shown to induce the expression of several pro-apoptosis mediators. It also can modulate the activity of anti-apoptosis mediators. However, certain cell-killing mechanisms such as senescence and autophagy can increase resistance to paclitaxel. This review focuses on the mechanisms of cell death, including apoptosis, mitotic catastrophe, senescence, autophagic cell death, pyroptosis, etc., following paclitaxel treatment. In addition, mechanisms of resistance to cell death due to exposure to paclitaxel and the use of combinations to overcome drug resistance will be discussed.

Breast cancer: molecular mechanisms of underlying resistance and therapeutic approaches

Breast cancer (BC) affects over 250,000 women in the US each year. Drug-resistant cancer cells are responsible for most breast cancer fatalities. Scientists are developing novel chemotherapeutic drugs and targeted therapy combinations to overcome cancer cell resistance. Combining drugs can reduce the chances of a tumor developing resistance to treatment. Clinical research has shown that combination chemotherapy enhances or improves survival, depending on the patient's response to treatment. Combination therapy is a highly successful supplemental cancer treatment. This review sheds light on intrinsic resistance to BC drugs and the importance of combination therapy for BC treatment. In addition to recurrence and metastasis of BC, the article discussed biomarkers for BC.

Review article epithelial to mesenchymal transition‑associated microRNAs in breast cancer

Despite major advances, breast cancer (BC) is the most commonly diagnosed carcinoma and remains a deadly disease among women worldwide. Many researchers point toward an important role of an epithelial to mesenchymal transition (EMT) in BC development and promoting metastasis. Here, will be discussed that how functional changes of transcription factors, signaling pathways, and microRNAs (miRNA) in BC promote EMT. A thorough understanding the EMT biology can be important to determine reversing the process and design treatment approaches. There are frequent debates as to whether EMT is really relevant to BC in vivo, in which due to the intrinsic heterogeneity and tumor microenvironment. Nevertheless, given the importance of EMT in cancer progression and metastasis, the implementation of therapies against cancer-associated EMT will continue to help us develop and test potential treatments.

Micro-RNAs in Response to Active Forms of Vitamin D3 in Human Leukemia and Lymphoma Cells

Non-coding micro-RNA (miRNAs) regulate the protein expression responsible for cell growth and proliferation. miRNAs also play a role in a cancer cells’ response to drug treatment. Knowing that leukemia and lymphoma cells show different responses to active forms of vitamin D₃, we decided to investigate the role of selected miRNA molecules and regulated proteins, analyzing if there is a correlation between the selected miRNAs and regulated proteins in response to two active forms of vitamin D₃, calcitriol and tacalcitol. A total of nine human cell lines were analyzed: five leukemias: MV-4-1, Thp-1, HL-60, K562, and KG-1; and four lymphomas: Raji, Daudi, Jurkat, and U2932. We selected five miRNA molecules—miR-27b, miR-32, miR-125b, miR-181a, and miR-181b—and the proteins regulated by these molecules, namely, CYP24A1, Bak1, Bim, p21, p27, p53, and NF-kB. The results showed that the level of selected miRNAs correlates with the level of proteins, especially p27, Bak1, NFκB, and CYP24A1, and miR-27b and miR-125b could be responsible for the anticancer activity of active forms of vitamin D₃ in human leukemia and lymphoma.

A systematic review on the role of MSC-derived exosomal miRNAs in the treatment of heart failure

BACKGROUND

This systematic review summarizes results of studies that evaluated the expression of microRNAs (miRs) in pre-diabetes or type 2 diabetes.

METHODS

The information was obtained in PubMed, EMBL-EBI, Wanfang, Trip Database, Lilacs, CINAHL and Google. A qualitative synthesis of the results was performed and miRs frequency was graphically. From 1880 we identified studies, only 53 fulfilled the inclusion criteria. The 53 studies analyzed miRs in T2D; and of them, thirteen also described data in pre-diabetes.

RESULTS

In diabetics, 122 miRs were reported and 35 miRs for pre-diabetics. However, we identified that 5 miRs (-122-5p, 144-3p, 210, 375, -126b) were reported more often in diabetics, and 4 (144-3p, -192, 29a and -30d) in pre-diabetics.

CONCLUSIONS

Circulating miRs could be used as biomarkers of type 2 diabetes. However, it is necessary to validate these microRNAs in prospective and multi-center studies, where different population subgroups, considering the age, gender, and risk factors.

MicroRNA Signatures in the Upper Urinary Tract Urothelial Carcinoma Scenario: Ready for the Game Changer?

Upper urinary tract urothelial carcinoma (UTUC) represents a minor subgroup of malignancies arising in the urothelium of the renal pelvis or ureter. The estimated annual incidence is around 2 cases per 100,000 people, with a mean age at diagnosis of 73 years. UTUC is more frequently diagnosed in an invasive or metastatic stage. However, even though the incidence of UTUC is not high, UTUC tends to be aggressive and rapidly progressing with a poor prognosis in some patients. A significant challenge in UTUC is ensuring accurate and timely diagnosis, which is complicated by the non-specific nature of symptoms seen at the onset of disease. Moreover, there is a lack of biomarkers capable of identifying the early presence of the malignancy and guide-tailored medical treatment. However, the growing understanding of the molecular biology underlying UTUC has led to the discovery of promising new biomarkers. Among these biomarkers, there is a class of small non-coding RNA biomarkers known as microRNAs (miRNAs) that are particularly promising. In this review, we will analyze the main characteristics of UTUC and focus on microRNAs as possible novel tools that could enter clinical practice in order to optimize the current diagnostic and prognostic algorithm.

The p53 Pathway Related Genes Predict the Prognosis of Colon Cancer

Background

Colon cancer is a common gastrointestinal malignancy. This study aimed to explore the relationship between p53 pathway-related genes and prognosis of colon cancer.

Methods

The mRNA datasets of colon cancer and adjacent tissues were downloaded from The Cancer Genome Atlas (TCGA) database, and the differential expression of genes in two groups was analyzed. Then, P53 pathway-related genes were intersected with differentially expressed genes (DEGs) to obtain P53 pathway-related differentially expressed genes. Then, overall survival (OS), disease-specific survival (DSS), and progression-free survival (PFS) in clusters were compared by consistent cluster analysis. Univariate and multivariate Cox regression analysis of DEGs was performed to obtain survival-related DEGs. Risk scores were calculated for each sample based on survival-related DEGs, and patients were divided into high/low risk scores. Prognostic differences, tumor immune cell infiltration levels, and immune pathway activation status were compared between the two groups.

Results

We identified 28 DEGs and two clusters. There are significant differences in PFS between the two clusters (P=0.011), and no significant difference between OS and DSS. We obtained 3 DEGs (CDKN2A, BAK1, BTG1) that were significantly related to PFS, and CDKN2A was considered an independent prognostic factor. PFS showed statistically significant difference between high/low risk score groups (P=0.015). There were significant differences in immune cell infiltration level and immune pathway activity between two groups.

Conclusion

The p53 pathway-related genes are significantly related to PFS in colon cancer patients and play an important role in regulating the tumor immune microenvironment.

Cancer drug resistance related microRNAs: recent advances in detection methods

MiRNAs are related to cancer drug resistance through various mechanisms. The advanced detection methods for the miRNAs are reviewed.

The Role of MiRNA in Cancer: Pathogenesis, Diagnosis, and Treatment

Cancer is also determined by the alterations of oncogenes and tumor suppressor genes. These gene expressions can be regulated by microRNAs (miRNA). At this point, researchers focus on addressing two main questions: "How are oncogenes and/or tumor suppressor genes regulated by miRNAs?" and "Which other mechanisms in cancer cells are regulated by miRNAs?" In this work we focus on gathering the publications answering these questions. The expression of miRNAs is affected by amplification, deletion or mutation. These processes are controlled by oncogenes and tumor suppressor genes, which regulate different mechanisms of cancer initiation and progression including cell proliferation, cell growth, apoptosis, DNA repair, invasion, angiogenesis, metastasis, drug resistance, metabolic regulation, and immune response regulation in cancer cells. In addition, profiling of miRNA is an important step in developing a new therapeutic approach for cancer.

MicroRNA function can be reversed by altering target gene expression levels

Paradoxically, many microRNAs appear to exhibit entirely opposite functions when placed in different contexts. For example, miR-125b has been shown to be pro-apoptotic in some studies, but anti-apoptotic in others. To investigate this phenomenon, we combine computational modeling with experimental approaches to examine how the function of miR-125b in apoptosis varies with respect to the expression levels of its pro-apoptotic and anti-apoptotic targets. In doing so, we elucidate a general trend that miR-125b is more pro-apoptotic when its anti-apoptotic targets are overexpressed, whereas it is more anti-apoptotic when its pro-apoptotic targets are overexpressed. We show that it is possible to completely reverse miR-125b′s function in apoptosis by modifying the expression levels of its target genes. Furthermore, miR-125b′s function may also be altered by the presence of anticancer drugs. These results suggest that the function of a microRNA can vary substantially and is dependent on its target gene expression levels.

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Many miRNAs exhibit entirely opposite functions when placed in different contexts

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miR-125b can be pro- or anti-apoptotic depending on target gene expression levels

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The function of a miRNA can be reversed by altering target gene expression levels

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The presence of anticancer drugs can also alter a miRNA's function

The Role of Non-Coding RNAs in Breast Cancer Drug Resistance

Breast cancer (BC) is one of the commonly occurring malignancies in females worldwide. Despite significant advances in therapeutics, the mortality and morbidity of BC still lead to low survival and poor prognosis due to the drug resistance. There are certain chemotherapeutic, endocrine, and target medicines often used for BC patients, including anthracyclines, taxanes, docetaxel, cisplatin, and fluorouracil. The drug resistance mechanisms of these medicines are complicated and have not been fully elucidated. It was reported that non-coding RNAs (ncRNAs), such as micro RNAs (miRNA), long-chain non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) performed key roles in regulating tumor development and mediating therapy resistance. However, the mechanism of these ncRNAs in BC chemotherapeutic, endocrine, and targeted drug resistance was different. This review aims to reveal the mechanism and potential functions of ncRNAs in BC drug resistance and to highlight the ncRNAs as a novel target for achieving improved treatment outcomes for BC patients.

Circulating and Intracellular miRNAs as Prognostic and Predictive Factors in HER2-Positive Early Breast Cancer Treated with Neoadjuvant Chemotherapy: A Review of the Literature

MicroRNAs (miRNA) are small noncoding RNAs that can act as both oncogene and tumor suppressors. Deregulated miRNA expression has been detected in human cancers, including breast cancer (BC). Considering their important roles in tumorigenesis, miRNAs have been investigated as potential prognostic and diagnostic biomarkers. Neoadjuvant setting is an optimal model to investigate in vivo the mechanism of treatment resistance. In the management of human epidermal growth factor receptor-2 (HER2)-positive early BC, the anti-HER2-targeted therapies have drastically changed the survival outcomes. Despite this, growing drug resistance due to the pressure of therapy is relatively frequent. In the present review, we focused on the main miRNAs involved in HER2-positive BC tumorigenesis and discussed the recent evidence on their predictive and prognostic value.

MicroRNAs as a clue to overcome breast cancer treatment resistance

Breast cancer is the most frequent cancer in women worldwide. Despite the improvement in diagnosis and treatments, the rates of cancer relapse and resistance to therapies remain higher than desirable. Alterations in microRNAs have been linked to changes in critical processes related to cancer development and progression. Their involvement in resistance or sensitivity to breast cancer treatments has been documented by different in vivo and in vitro experiments. The most significant microRNAs implicated in modulating resistance to breast cancer therapies are summarized in this review. Resistance to therapy has been linked to cellular processes such as cell cycle, apoptosis, epithelial-to-mesenchymal transition, stemness phenotype, or receptor signaling pathways, and the role of microRNAs in their regulation has already been described. The modulation of specific microRNAs may modify treatment response and improve survival rates and cancer patients' quality of life. As a result, a greater understanding of microRNAs, their targets, and the signaling pathways through which they act is needed. This information could be useful to design new therapeutic strategies, to reduce resistance to the available treatments, and to open the door to possible new clinical approaches.

Multiple interactions between melatonin and non-coding RNAs in cancer biology

The melatonin hormone secreted by the pineal gland is involved in physiological functions such as growth and maturation, circadian cycles, and biological activities including antioxidants, anti-tumor, and anti-ischemia. Melatonin not only interacts with proteins but also has functional effects on regulatory RNAs such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs). In this study, we overview various physiological and pathological conditions affecting melatonin through lncRNA and miRNA. The information compiled herein will serve as a solid foundation to formulate ideas for future mechanistic studies on melatonin. It will also provide a chance to more clarify the emerging functions of the non-coding transcriptome.

A comprehensive in vivo screen for anti-apoptotic miRNAs indicates broad capacities for oncogenic synergy

microRNAs (miRNAs) are ~21-22 nucleotide (nt) RNAs that mediate broad post-transcriptional regulatory networks. However, genetic analyses have shown that the phenotypic consequences of deleting individual miRNAs are generally far less overt compared to their misexpression. This suggests that miRNA deregulation may have broader phenotypic impacts during disease situations. We explored this concept in the Drosophila eye, by screening for miRNAs whose misexpression could modify the activity of pro-apoptotic factors. Via unbiased and comprehensive in vivo phenotypic assays, we identify an unexpectedly large set of miRNA hits that can suppress the action of pro-apoptotic genes hid and grim. We utilize secondary assays to validate that a subset of these miRNAs can inhibit irradiation-induced cell death. Since cancer cells might seek to evade apoptosis pathways, we modeled this situation by asking whether activation of anti-apoptotic miRNAs could serve as "second hits". Indeed, while clones of the lethal giant larvae (lgl) tumor suppressor are normally eliminated during larval development, we find that diverse anti-apoptotic miRNAs mediate the survival of lgl mutant clones in third instar larvae. Notably, while certain anti-apoptotic miRNAs can target apoptotic factors, most of our screen hits lack obvious targets in the core apoptosis machinery. These data highlight how a genetic approach can reveal distinct and powerful activities of miRNAs in vivo, including unexpected functional synergies during disease or cancer-relevant settings.

Breast Cancer Response to Therapy: Can microRNAs Lead the Way?

Breast cancer (BC) is a leading cause of death among women with malignant diseases. The selection of adequate therapies for highly invasive and metastatic BCs still represents a major challenge. Novel combinatorial therapeutic approaches are urgently required to enhance the efficiency of BC treatment. Recently, microRNAs (miRNAs) emerged as key regulators of the complex mechanisms that govern BC therapeutic resistance and susceptibility. In the present review we aim to critically examine how miRNAs influence BC response to therapies, or how to use miRNAs as a basis for new therapeutic approaches. We summarized recent findings in this rapidly evolving field, emphasizing the challenges still ahead for the successful implementation of miRNAs into BC treatment while providing insights for future BC management.The goal of this review was to propose miRNAs, that might simultaneously improve the efficacy of all four therapies that are the backbone of current BC management (radio-, chemo-, targeted, and hormone therapy). Among the described miRNAs, miR-21 and miR-16 emerged as the most promising, closely followed by miR-205, miR-451, miR-182, and miRNAs from the let-7 family. miR-21 inhibition might be the best choice for future improvement of invasive BC treatment.New therapeutic strategies of miRNA-based agents alongside current standard treatment modalities could greatly benefit BC patients. This review represents a guideline on how to navigate this elaborate puzzle.

Differential miRNA Expression Profiling Reveals Correlation of miR125b-5p with Persistent Infection of Japanese Encephalitis Virus

MicroRNAs (miRNAs) play versatile roles in multiple biological processes. However, little is known about miRNA’s involvement in flavivirus persistent infection. Here, we used an miRNA array analysis of Japanese encephalitis virus (JEV)-infected cells to search for persistent infection-associated miRNAs in comparison to acute infection. Among all differentially expressed miRNAs, the miR-125b-5p is the most significantly increased one. The high level of miR-125b-5p in persistently JEV-infected cells was confirmed by Northern analysis and real-time quantitative polymerase chain reaction. As soon as the cells established a persistent infection, a significantly high expression of miR-125b-5p was readily observed. Transfecting excess quantities of a miR-125b-5p mimic into acutely infected cells reduced genome replication and virus titers. Host targets of miR125b-5p were analyzed by target prediction algorithms, and six candidates were confirmed by a dual-luciferase reporter assay. These genes were upregulated in the acutely infected cells and sharply declined in the persistently infected cells. The transfection of the miR125b-5p mimic reduced the expression levels of Stat3, Map2k7, and Triap1. Our studies indicated that miR-125b-5p targets both viral and host sequences, suggesting its role in coordinating viral replication and host antiviral responses. This is the first report to characterize the potential roles of miR-125b-5p in persistent JEV infections.

Gene Therapy as an Emerging Therapeutic Approach to Breast Cancer: New Developments and Challenges

Breast cancer is a heterogeneous disease, which is the consequence of several genetic and environmental factors. Also, it is one of the most common causes of cancer death and second leading cancer among women all around the world. Therefore, it is necessary to develop novel therapeutic approaches useful for the successful treatment of breast cancer. As conventional treatments had limited success, alternative approaches for the treatment of breast cancer have been applied in recent years. Hence, the molecular basis of breast cancer has provided the opportunity of using genetic materials for therapeutic uses. In this regard, gene therapy as one of the potentially efficient and beneficial treatments among various techniques became a popular treatment for different cancers, especially breast cancer. Accordingly, there are plenty of targets available for gene therapy of breast cancer. Gene therapy strategies have the potential to correct molecular defects that contributed to the cancer progression. These techniques should selectively target tumor cells without affecting normal cells. Moreover, data of clinical trials in gene therapy for breast cancer indicated that this approach has little toxicity compared to other therapeutic approaches. In this study, different aspects of breast neoplasm, gene therapy techniques, challenges, and recent developments will be mentioned.