MicroRNA-181a promotes docetaxel resistance in prostate cancer cells

Overcoming chemoresistance and radio resistance in prostate cancer: The emergent role of non-coding RNAs

Prostate cancer (PCa) continues to be a major health concern worldwide, with its resistance to chemotherapy and radiation therapy presenting major hurdles in successful treatment. While patients with localized prostate cancer generally have a good survival rate, those with metastatic prostate cancer often face a grim prognosis, even with aggressive treatments using various methods. The high mortality rate in severe cases is largely due to the lack of treatment options that can offer lasting results, especially considering the significant genetic diversity found in tumors at the genomic level. This comprehensive review examines the intricate molecular mechanisms governing resistance in PCa, emphasising the pivotal contributions of non-coding RNAs (ncRNAs). We delve into the diverse roles of microRNAs, long ncRNAs, and other non-coding elements as critical regulators of key cellular processes involved in CR & RR. The review emphasizes the diagnostic potential of ncRNAs as predictive biomarkers for treatment response, offering insights into patient stratification and personalized therapeutic approaches. Additionally, we explore the therapeutic implications of targeting ncRNAs to overcome CR & RR, highlighting innovative strategies to restore treatment sensitivity. By synthesizing current knowledge, this review not only provides a comprehension of the chemical basis of resistance in PCa but also identifies gaps in knowledge, paving the way for future research directions. Ultimately, this exploration of ncRNA perspectives offers a roadmap for advancing precision medicine in PCa, potentially transforming therapeutic paradigms and improving outcomes for patients facing the challenges of treatment resistance.

From resistance to resilience: Uncovering chemotherapeutic resistance mechanisms; insights from established models

Despite the tremendous advances in cancer treatment, resistance to chemotherapeutic agents impedes higher success rates and accounts for major relapses in cancer therapy. Moreover, the resistance of cancer cells to chemotherapy is linked to low efficacy and high recurrence of cancer. To stand up against chemotherapy resistance, different models of chemotherapy resistance have been established to study various molecular mechanisms of chemotherapy resistance. Consequently, this review is going to discuss different models of induction of chemotherapy resistance, highlighting the most common mechanisms of cancer resistance against different chemotherapeutic agents, including overexpression of efflux pumps, drug inactivation, epigenetic modulation, and epithelial-mesenchymal transition. This review aims to open a new avenue for researchers to lower the resistance to the existing chemotherapeutic agents, develop new therapeutic agents with low resistance potential, and establish possible prognostic markers for chemotherapy resistance.

Functions, mechanisms, and clinical applications of lncRNA LINC00857 in cancer pathogenesis

Emerging data indicated that long noncoding RNAs (lncRNAs) are crucial players in the biological processes via regulating epigenetics, transcription, and protein translation. A novel lncRNA, LINC00857, was indicated to upregulate in several types of cancer. In addition, LINC00857 was functionally related to the modulation of the cancer-linked behaviors, including invasion, migration, proliferation, epithelial-mesenchymal transition (EMT), cell cycle, and apoptosis. The importance of LINC00857 in cancer onset and development proposed that LINC00857 has major importance in the cancer progression and may be considered as a novel prognostic/diagnostic biomarker as well as a treatment target. Here, we retrospectively investigate the available progress in biomedical research investigating the functions of LINC00857 in cancer, focusing on finding the molecular mechanisms affecting various cancer-related behaviors and exploring its clinical applications.

Double-edged sword role of miRNA-633 and miRNA-181 in human cancers

Understanding the function and mode of operation of microRNAs (miRNAs) in cancer is of growing interest. The short non-coding RNAs known as miRNAs, which target mRNA in multicellular organisms, are described as controlling essential cellular processes. The miR-181 family and miR-633 are well-known miRNAs that play a key role in the development and metastasis of tumor cells. They may facilitate either tumor-suppressive or oncogenic function in malignant cells, according to mounting evidence. Metastatic cells that are closely linked to cancer cell migration, invasion, and angiogenesis can be identified by abnormal levels of miR-181 and miR-633. Numerous studies have demonstrated their capacity to control drug resistance, cell growth, apoptosis, and the epithelial-mesenchymal transition (EMT) and metastasis process. Interestingly, the levels of miR-181 and miR-633 and their potential target genes in the basic cellular process can vary depending on the type of cancer cells and their gene expression profile. Such miRNAs' interactions with other non-coding RNAs such as long non-coding RNAs and circular RNAs can influence tumor behaviors. Herein, we concentrated on the multifaceted roles of miR-181 and miR-633 and potential targets in human tumorigenesis, ranging from cell growth and metastasis to drug resistance.

The Emerging Role of Epigenetics in Metabolism and Endocrinology

Each cell in a multicellular organism has its own phenotype despite sharing the same genome. Epigenetics is a somatic, heritable pattern of gene expression or cellular phenotype mediated by structural changes in chromatin that occur without altering the DNA sequence. Epigenetic modification is an important factor in determining the level and timing of gene expression in response to endogenous and exogenous stimuli. There is also growing evidence concerning the interaction between epigenetics and metabolism. Accordingly, several enzymes that consume vital metabolites as substrates or cofactors are used during the catalysis of epigenetic modification. Therefore, altered metabolism might lead to diseases and pathogenesis, including endocrine disorders and cancer. In addition, it has been demonstrated that epigenetic modification influences the endocrine system and immune response-related pathways. In this regard, epigenetic modification may impact the levels of hormones that are important in regulating growth, development, reproduction, energy balance, and metabolism. Altering the function of the endocrine system has negative health consequences. Furthermore, endocrine disruptors (EDC) have a significant impact on the endocrine system, causing the abnormal functioning of hormones and their receptors, resulting in various diseases and disorders. Overall, this review focuses on the impact of epigenetics on the endocrine system and its interaction with metabolism.

MicroRNAs as clinical tools for diagnosis, prognosis, and therapy in prostate cancer

Prostate cancer (PCa) is one of the most commonly diagnosed cancers among men worldwide. Despite the presence of accumulated clinical strategies for PCa management, limited prognostic/sensitive biomarkers are available to follow up on disease occurrence and progression. MicroRNAs (miRNAs) are small non-coding RNAs that control gene expression through post-transcriptional regulation of their complementary target messenger RNA (mRNA). MiRNAs modulate fundamental biological processes and play crucial roles in the pathology of various diseases, including PCa. Multiple evidence proved an aberrant miRNA expression profile in PCa, which is actively involved in the carcinogenic process. The robust and pleiotropic impact of miRNAs on PCa suggests them as potential candidates to help more understand the molecular landscape of the disease, which is likely to provide tools for early diagnosis and prognosis as well as additional therapeutic strategies to manage prostate tumors. Here, we emphasize the most consistently reported dysregulated miRNAs and highlight the contribution of their altered downstream targets with PCa hallmarks. Also, we report the potential effectiveness of using miRNAs as diagnostic/prognostic biomarkers in PCa and the high-throughput profiling technologies that are being used in their detection. Another key aspect to be discussed in this review is the promising implication of miRNAs molecules as therapeutic tools and targets for fighting PCa.

microRNA-181a silencing by antisense oligonucleotides delivered by virus-like particles

Cowpea chlorotic mottle virus (CCMV) is a positive-sense RNA virus that can be repurposed for gene delivery applications. Understanding the self-assembly process of the virus enabled to remove its genome and replace it with desired nucleic acids, and we and others have previously reported using CCMV virus-like particle (VLP) to encapsulate siRNA, mRNA, as well as CpG oligodeoxynucleotides. In this study, the CCMV VLP was applied to encapsulate two different formats of anti-miR-181a oligonucleotides: naked RNA and chemically stabilized RNA to knockdown highly regulated miR-181a in ovarian cancer cells. miR-181a expression in ovarian tumors is associated with high aggressiveness, invasiveness, resistance to chemotherapy, and overall poor prognosis. Therefore, miR-181a is an important target for ovarian cancer therapy. qPCR data and cancer cell migration assays demonstrated higher knockdown efficacy when anti-miR-181a oligonucleotides were encapsulated and delivered using the VLPs resulting in reduced cancer cell invasiveness. Importantly, delivery of anti-miR-181a oligonucleotide into cells could be achieved without the aid of a transfection agent or surface modification. These results highlight the opportunity of plant-derived VLPs as nucleic acid carriers.

miRNAs in prostate cancer: Intercellular and extracellular communications

Prostate cancer is the most prevalent male cancer in Western Europe and North America. Although new drugs were recently approved, clinical challenges such as accurately predicting and screening drug-resistant prostate cancer remain. microRNAs are short noncoding RNA molecules that participate in gene regulation at the post-transcriptional level by targeting messenger RNAs. There is accumulating evidence that intracellular microRNAs play important roles as promoters or inhibitors of prostate cancer progression. Additionally, recent studies showed that microRNAs are encapsulated in extracellular vesicles and shuttled into the extracellular space. Transfer of extracellular microRNAs contributes to intercellular communication between prostate cancer cells and components of the tumor microenvironment, which can promote prostate cancer progression. Furthermore, due to their encapsulation in extracellular vesicles, extracellular microRNAs can be stably present in body fluids which contain high levels of RNase. Thus, circulating microRNAs have great potential as noninvasive diagnostic and prognostic biomarkers for prostate cancer. Here, we summarize the roles of intracellular and extracellular microRNAs in prostate cancer progression and discuss the potential of microRNA-based therapeutics as a novel treatment strategy for prostate cancer.

MicroRNA as a Potential Therapeutic Molecule in Cancer

Small noncoding RNAs, as post-translational regulators of many target genes, are not only markers of neoplastic disease initiation and progression, but also markers of response to anticancer therapy. Hundreds of miRNAs have been identified as biomarkers of drug resistance, and many have demonstrated the potential to sensitize cancer cells to therapy. Their properties of modulating the response of cells to therapy have made them a promising target for overcoming drug resistance. Several methods have been developed for the delivery of miRNAs to cancer cells, including introducing synthetic miRNA mimics, DNA plasmids containing miRNAs, and small molecules that epigenetically alter endogenous miRNA expression. The results of studies in animal models and preclinical studies for solid cancers and hematological malignancies have confirmed the effectiveness of treatment protocols using microRNA. Nevertheless, the use of miRNAs in anticancer therapy is not without limitations, including the development of a stable nanoconstruct, delivery method choices, and biodistribution. The aim of this review was to summarize the role of miRNAs in cancer treatment and to present new therapeutic concepts for these molecules. Supporting anticancer therapy with microRNA molecules has been verified in numerous clinical trials, which shows great potential in the treatment of cancer.

Molecular Investigation of miRNA Biomarkers as Chemoresistance Regulators in Melanoma: A Protocol for Systematic Review and Meta-Analysis

Introduction: Melanoma is a global disease that is predominant in Western countries. However, reliable data resources and comprehensive studies on the theragnostic efficiency of miRNAs in melanoma are scarce. Hence, a decisive study or comprehensive review is required to collate the evidence for profiling miRNAs as a theragnostic marker. This protocol details a comprehensive systematic review and meta-analysis on the impact of miRNAs on chemoresistance and their association with theragnosis in melanoma. Methods and analysis: The articles will be retrieved from online bibliographic databases, including Cochrane Review, EMBASE, MEDLINE, PubMed, Scopus, Science Direct, and Web of Science, with different permutations of ‘keywords’. To obtain full-text papers of relevant research, a stated search method will be used, along with selection criteria. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis for Protocols 2015 (PRISMA-P) standards were used to create this study protocol. The hazard ratio (HR) with a 95% confidence interval will be analyzed using Comprehensive Meta-Analysis (CMA) software 3.0. (CI). The pooled effect size will be calculated using a random or fixed-effects meta-analysis model. Cochran’s Q test and the I2 statistic will be used to determine heterogeneity. Egger’s bias indicator test, Orwin’s and the classic fail-safe N tests, the Begg and Mazumdar rank collection test, and Duval and Tweedie’s trim and fill calculation will all be used to determine publication bias. The overall standard deviation will be evaluated using Z-statistics. Subgroup analyses will be performed according to the melanoma participants’ clinicopathological and biological characteristics and methodological factors if sufficient studies and retrieved data are identified and available. The source of heterogeneity will be assessed using a meta-regression analysis. A pairwise matrix could be developed using either a pairwise correlation or expression associations of miRNA with patients’ survival for the same studies.

The miRNAs involved in prostate cancer chemotherapy response as chemoresistance and chemosensitivity predictors

BACKGROUND

Reliable molecular markers that allow the rational prescription of an effective chemotherapy type for each prostate cancer patient are still needed. Since microRNAs expression is associated with the response to different types of prostate cancer therapy, microRNAs represent a pool of perspective markers of therapy effectiveness comprising chemotherapy.

OBJECTIVES

The available data on microRNAs associated with chemotherapy response (resistance and sensitivity) are summarized and analyzed in the article.

MATERIALS AND METHODS

A review of the published data, as well as their analysis by current bioinformatics resources, was conducted. The molecular targets of microRNAs, as well as the reciprocal relationships between the microRNAs and their targets, were studied using the DIANA, STRING, and TransmiR databases. Special attention was dedicated to the mechanisms of prostate cancer chemoresistance development.

RESULTS AND DISCUSSION

The combined analysis of bioinformatics resources and the available literature indicated that the expression of eight microRNAs that are associated with different responses to chemotherapy have a high potential for the prediction of the prostate cancer chemotherapy response, as found in the experiments and confirmed by the functions of regulated genes.

CONCLUSION

An overview on the published data and bioinformatics resources, with respect to predictive microRNA markers of chemotherapy response, is presented in this review. The selected microRNA and gene panel has a high potential for predicting the chemosensitivity or chemoresistance of prostate cancer and could represent a set of markers for subsequent study using samples of cell-free microRNAs from different patient groups.

Role of noncoding RNA in drug resistance of prostate cancer

Prostate cancer is one of the most prevalent forms of cancer around the world. Androgen-deprivation treatment and chemotherapy are the curative approaches used to suppress prostate cancer progression. However, drug resistance is extensively and hard to overcome even though remarkable progress has been made in recent decades. Noncoding RNAs, such as miRNAs, lncRNAs, and circRNAs, are a group of cellular RNAs which participate in various cellular processes and diseases. Recently, accumulating evidence has highlighted the vital role of non-coding RNA in the development of drug resistance in prostate cancer. In this review, we summarize the important roles of these three classes of noncoding RNA in drug resistance and the potential therapeutic applications in this disease.

miRNA as Regulators of Prostate Carcinogenesis and Endocrine and Chemoresistance

More therapy options are available for advanced prostate cancer, including novel inhibitors of androgen synthesis, anti-androgens, chemotherapeutics and targeted therapies. Although patients ´ survival has been improved, management of castration therapy-resistant prostate cancer remains a challenge. Regulation of cellular events in cancer by small non-coding miRNAs is, therefore, an area of special interest. Overexpression of selected miRNA may lead to androgen independence and prostate cancer progression. miRNA may be considered also a biomarker in patients with prostate cancer. In contrast, diminished expression of tumor-suppressive miRNA in prostate cancer leads to enhanced proliferation, reduced apoptosis, increased migration, invasion and epithelial- to-mesenchymal transition. miRNA may be directly involved in the regulation of chemosensitivity in prostate cancer. Experimental overexpression of selected miRNA in chemoresistant prostate cancer leads to the inhibition of cellular stemness and epithelial-to-mesenchymal transition. Reduction of tumor-suppressive miRNA may also lead to hyperactivity of signaling pathways such as that of the epidermal growth factor receptor and mitogen-activated protein kinase. Although considerable progress on miRNA research in prostate cancer has been achieved, therapeutic effects could be improved on the basis of the development of novel delivery methods.

Protein Disulfide Isomerase 4 Drives Docetaxel Resistance in Prostate Cancer

BACKGROUND

Protein disulfide isomerase 4 (PDIA4) has been reported to be closely associated with chemoresistance in several types of malignancies. But the pathogenic mechanisms of PDIA4 involved in docetaxel (DTX) resistance in prostate cancer (PCa) are still unknown. Hence, this study was conducted to evaluate the potential effect of PDIA4 on chemoresistance to DTX in PCa cells and to investigate the underlying mechanisms.

METHODS

Two types of DTX-resistant PCa cells, that is, DTX-resistant PC-3 cells (PC-3/DTXR) and C4-2B cells (C4-2B/DTXR) were developed, as well as the parental PC-3 and C4-2B cells were obtained to investigate these issues. Short hairpin RNAs targeting human PDIA4 to knockdown the expression of PDIA4 or PDIA4-expressing adenoviral vectors to overexpress the PDIA4 were transfected into PCa cells to study the underlying mechanisms of PDIA4 involving in PCa DTX resistance.

RESULTS

Results showed that PDIA4 exhibited a dramatic overexpression in PC-3/DTXR and C4-2B/DTXR cells. Down-regulation of PDIA4 by infecting PC-3/DTXR and C4-2B/DTXR cells with shPDIA4 lentivirus stimulated cell death by prompting apoptosis. Up-regulation of PDIA4 by infecting PC-3 and C4-2B cells with PDIA4-expressing adenovirus showed severer resistance to DTX. In addition, PDIA4 up-regulation induced phosphorylated protein kinase B (Akt) expression, while PDIA4 knockdown significantly inhibited the expression in PCa cells.

CONCLUSIONS

Our study indicates that PDIA4 is a negative regulator of PCa cell apoptosis and plays a critical role in PCa DTX resistance by activating the Akt-signaling pathway. Thereby, it implies that targeting PDIA4 could be a potential adjuvant therapeutic approach against DTX resistance in PCa.

Mechanisms of docetaxel resistance in prostate cancer: The key role played by miRNAs

One of the main problems with the treatment of metastatic prostate cancer is that, despite an initial positive response, the majority of patients develop resistance and progress. In particular, the resistance to docetaxel, the gold standard therapy for metastatic prostate cancer since 2010, represents one of the main factors responsible for the failure of prostate cancer therapy. According to the present knowledge, different processes contribute to the appearance of docetaxel resistance and non-coding RNA seems to play a relevant role in them. In this review, a comprehensive overview of the miRNA network involved in docetaxel resistance is described, highlighting the pathway/s affected by their activity.

New Insights into Mechanisms of Endocrine-Disrupting Chemicals in Thyroid Diseases: The Epigenetic Way

In recent years, the presence in the environment of chemical compounds with thyroid-disrupting effects is progressively increased. This phenomenon has risen concern for human health as the preservation of thyroid system homeostasis is essential for fetal development and for maintaining psychological and physiological wellbeing. An increasing number of studies explored the role of different classes of toxicants in the occurrence and severity of thyroid diseases, but large epidemiological studies are limited and only a few animal or in vitro studies have attempted to identify the mechanisms of chemical action. Recently, epigenetic changes such as alteration of methylation status or modification of non-coding RNAs have been suggested as correlated to possible deleterious effects leading to different thyroid disorders in susceptible individuals. This review aims to analyze the epigenetic alterations putatively induced by chemical exposures and involved in the onset of frequent thyroid diseases such as thyroid cancer, autoimmune thyroiditis and disruption of fetal thyroid homeostasis.

Upregulation of Akt/Raptor signaling is associated with rapamycin resistance of breast cancer cells

mTOR inhibitors are considered today to be one of the most promising anticancer drugs. Here to study the mechanism of the acquired resistance of MCF-7 breast cancer cells to mTOR inhibitors two different models of the cell resistance were used: rapamycin-resistant MCF-7/Rap subline developed under long-term rapamycin treatment, and metformin-resistant MCF-7/M subline obtained by long-term metformin treatment. We have found that both resistant sublines were characterized by common features: increased expression of mTOR-interacting Raptor protein, increased phosphorylation of Akt, and activation of growth-related transcriptional factor AP-1. Cell response to mTOR inhibitors was partially restored under treatment with PI3K inhibitor wortmannin supporting the direct connection between Akt activation and poor cell response to therapeutic drugs. Transfection of mir-181c, one of the positive regulators of Akt and mTOR, led to an increase in the cell resistance to both mTOR inhibitors, rapamycin and metformin, which correlated with Raptor overexpression and activation of Akt/AP-1 signaling. In general, the effect of Raptor overexpression in the resistant cells, as well as the ability of mir-181c to modulate the Raptor expression, can open novel perspectives in the treatment of rapalogues-resistant cancers, based on the drugs design targeting mir-181c/Raptor axis.

Non-coding RNAs in drug resistance of head and neck cancers: A review

Head and neck cancer (HNC), which includes epithelial malignancies of the upper aerodigestive tract (oral cavity, oropharynx, pharynx, hypopharynx, larynx, and thyroid), are slowly but consistently increasing, while the overall survival rate remains unsatisfactory. Because of the multifunctional anatomical intricacies of the head and neck, disease progression and therapy-related side effects often severely affect the patient's appearance and self-image, as well as their ability to breathe, speak, and swallow. Patients with HNC require a multidisciplinary approach involving surgery, radiation therapy, and chemotherapeutics. Chemotherapy is an important part of the comprehensive treatment of tumors, especially advanced HNC, but drug resistance is the main cause of poor clinical efficacy. The most important determinant of this phenomenon is still largely unknown. Recent studies have shown that non-coding RNAs have a crucial role in HNC drug resistance. In addition, they can serve as biomarkers in the diagnosis, treatment, and prognosis of HNCs. In this review, we summarize the relationship between non-coding RNAs and drug resistance of HNC, and discuss their potential clinical application in overcoming HNC chemoresistance.

Resistance Mechanisms to Taxanes and PARP Inhibitors in Advanced Prostate Cancer

The clinical landscape concerning advanced prostate cancer is rapidly changing and reaching beyond androgen deprivation therapy and androgen receptor targeted therapies. Taxane chemotherapy is a critical tool in the management of advanced prostate cancer. Additionally, novel drug classes such as PARP inhibitors are being investigated. Despite tremendous progress, resistance to therapy remains as a major impediment to further improvement. Resistance mechanisms appear diverse and are not fully known or understood. This review will highlight recent advances in research regarding mechanisms of resistance to both taxanes (such as increased drug efflux capacity) and PARP inhibitors (such as reversion mutations which restore DNA-repair proficiency). Understanding resistance to therapy promises to remove barriers blocking progress toward improved patient outcomes.

Exploring the Potential of MicroRNA Let-7c as a Therapeutic for Prostate Cancer

Prostate cancer (PCa) is one of the leading causes of mortality worldwide and often presents with aberrant microRNA (miRNA) expression. Identifying and understanding the unique expression profiles could aid in the detection and treatment of this disease. This review aims to identify miRNAs as potential therapeutic targets for PCa. Three bio-informatic searches were conducted to identify miRNAs that are reportedly implicated in the pathogenesis of PCa. Only hsa-Lethal-7 (let-7c), recognized for its role in PCa pathogenesis, was common to all three databases. Three further database searches were conducted to identify known targets of hsa-let-7c. Four targets were identified, HMGA2, c-Myc (MYC), TRAIL, and CASP3. An extensive review of the literature was undertaken to assess the role of hsa-let-7c in the progression of other malignancies and to evaluate its potential as a therapeutic target for PCa. The heterogeneous nature of cancer makes it logical to develop mechanisms by which the treatment of malignancies is tailored to an individual, harnessing specific knowledge of the underlying biology of the disease. Resetting cellular miRNA levels is an exciting prospect that will allow this ambition to be realized.

Clinical Theragnostic Relationship between Drug-Resistance Specific miRNA Expressions, Chemotherapeutic Resistance, and Sensitivity in Breast Cancer: A Systematic Review and Meta-Analysis

Awareness of breast cancer has been increasing due to early detection, but the advanced disease has limited treatment options. There has been growing evidence on the role of miRNAs involved in regulating the resistance in several cancers. We performed a comprehensive systematic review and meta-analysis on the role of miRNAs in influencing the chemoresistance and sensitivity of breast cancer. A bibliographic search was performed in PubMed and Science Direct based on the search strategy, and studies published until December 2018 were retrieved. The eligible studies were included based on the selection criteria, and a detailed systematic review and meta-analysis were performed based on PRISMA guidelines. A random-effects model was utilised to evaluate the combined effect size of the obtained hazard ratio and 95% confidence intervals from the eligible studies. Publication bias was assessed with Cochran’s Q test, I² statistic, Orwin and Classic fail-safe N test, Begg and Mazumdar rank correlation test, Duval and Tweedie trim and fill calculation and the Egger’s bias indicator. A total of 4584 potential studies were screened. Of these, 85 articles were eligible for our systematic review and meta-analysis. In the 85 studies, 188 different miRNAs were studied, of which 96 were upregulated, 87 were downregulated and 5 were not involved in regulation. Overall, 24 drugs were used for treatment, with doxorubicin being prominently reported in 15 studies followed by Paclitaxel in 11 studies, and 5 drugs were used in combinations. We found only two significant HR values from the studies (miR-125b and miR-4443) and our meta-analysis results yielded a combined HR value of 0.748 with a 95% confidence interval of 0.508–1.100; p-value of 0.140. In conclusion, our results suggest there are different miRNAs involved in the regulation of chemoresistance through diverse drug genetic targets. These biomarkers play a crucial role in guiding the effective diagnostic and prognostic efficiency of breast cancer. The screening of miRNAs as a theragnostic biomarker must be brought into regular practice for all diseases. We anticipate that our study serves as a reference in framing future studies and clinical trials for utilising miRNAs and their respective drug targets.

MiR-146b inhibits autophagy in prostate cancer by targeting the PTEN/Akt/mTOR signaling pathway

Prostate cancer (PCa) is considered as a common visceral cancer in males and the sixth major cause of cancer-related deaths in males worldwide. Significant diagnostic and therapeutic advances have been made in the past decades. However, an improved understanding of their molecular mechanism is still needed. In the present research, we first detected the expression of miR-146b by quantitative real-time PCR (qRT-PCR) and found that miR-146b expression was increased in PCa. Subsequently, we found that miR-146b play an important role in the viability and proliferation capacity of PCa cells functionally. To explore the mechanism, we performed western blot to examine the autophagy-related markers, and found that miR‑146b may promote autophagy in PCa cells via activation of PTEN/AKT/mTOR signaling pathway. Furthermore, we performed the dual luciferase reporter assay to clarify the relationship between miR-146b and PTEN. In conclusion, this study demonstrated that miR-146b inhibited autophagy in PCa by targeting the PTEN/Akt/mTOR signaling pathway, and it could be a potential candidate for application in the treatment of PCa.

Current Evidence on miRNAs as Potential Theranostic Markers for Detecting Chemoresistance in Colorectal Cancer: A Systematic Review and Meta-Analysis of Preclinical and Clinical Studies

BACKGROUND

Findings from observational clinical studies examining the relationship between biomarker expression and theranosis in colorectal cancer (CRC) have been conflicting.

OBJECTIVE

We conducted this systematic review and meta-analysis to summarise the existing evidence to demonstrate the involvement of microRNAs (miRNAs) in chemoresistance and sensitivity in CRC through drug genetic pathways.

METHODS

Using PRISMA guidelines, we systematically searched PubMed and Science Direct for relevant studies that took place between 2012 and 2017. A random-effects model of meta-analysis was applied to evaluate the pooled effect size of hazard ratios (HRs) across the included studies. Cochran's Q test and the I² statistic were used to detect heterogeneity. A funnel plot was used to assess potential publication bias.

RESULTS

Of the 4700 studies found, 39 studies comprising 2822 patients with CRC met the inclusion criteria. The included studies used one or a combination of 14 chemotherapy drugs, including 5-fluorouracil and oxaliplatin. Of the 60 miRNAs, 28 were associated with chemosensitivity, 20 with chemoresistance, and one with differential expression and radiosensitivity; ten miRNAs were not associated with any impact on chemotherapy. The results outline the importance of 34 drug-regulatory pathways of chemoresistance and sensitivity in CRC. The mean effect size was 0.689 (95% confidence interval 0.428-1.110), indicating that the expression of miRNAs decreased the likelihood of death by about 32%.

CONCLUSION

Studies have consistently shown that multiple miRNAs could act as clinical predictors of chemoresistance and sensitivity. An inclusion of supplementary miRNA estimation in CRC routine practice needs to be considered to evaluate the efficacy of chemotherapy after confirming our findings with large-scale prospective cohort studies.

PROSPERO REGISTRATION NUMBER

CRD42017082196.

Expression of miR-195 and MEK1 in patients with bladder cancer and their relationship to prognosis

OBJECTIVE

MAPK kinase 1 (MEK1) plays an important role in regulating cell proliferation and apoptosis through activation of the ERK/MAPK signaling pathway. It was found that the expression of miR-195 in bladder cancer was abnormally decreased, suggesting that miR-195 may affect the development of bladder cancer. In this study, we examined the expression of miR-195 and MEK1 in bladder cancer tissues and analyzed the relationship between miR-195 and MEK1 in cell proliferation and apoptosis in bladder cancer cells.

PATIENTS AND METHODS

The expression of MEK1 in bladder cancer tissues was detected by western blot, and the expression levels of miR-195 and MEK1 mRNA were detected by qRT-PCR. Log Rank test was used to compare the survival and prognosis of patients with low and high expression of miR-195 and MEK1 by using the median expression of miR-195 and MEK1. Bioinformatics analysis and double luciferase reporter gene test were used to verify the relationship between miR-195 and MEK1. Bladder cancer BIU-87 and 5637 cells were cultured in vitro and divided into two groups: miR-NC group and miR-195 mimic group. The expression of MEK1 and p-MEK1 protein was detected by western blot, apoptosis was detected by flow cytometry, and cell proliferation was detected by EdU staining.

RESULTS

Compared with normal bladder tissue, expression of miR-195 in bladder cancer tissue was significantly decreased, while the expression of MEK1 mRNA and protein was significantly increased. The prognosis of patients with low expression of miR-195 was worse than those with high expression of miR-195. The prognosis of patients with low expression of MEK1 was better than those with high expression of MEK1. Bioinformatics analysis showed that there was a target complementary binding site between miR-195 and MEK1. Double luciferase reporter gene experiments confirmed that there was a target regulatory relationship between miR-195 and MEK1. miR-195 mimic transfection could significantly down-regulate the expression of MEK1 and p-MEK1 proteins in BIU-87 and 5637 cells, weaken cell proliferation, and increase cell apoptosis.

CONCLUSION

Overexpression of miR-195 can inhibit the proliferation of bladder cancer cells by inhibiting MEK1, which provides further evidence for developing therapy against bladder cancer.

A panel of seven-miRNA signature in plasma as potential biomarker for colorectal cancer diagnosis

Colorectal cancer (CRC) has been one of the most commonly diagnosed cancers in global. The differential expression profiles of microRNAs (miRNAs) in CRC plasma of patients have the potential to serve as a diagnostic biomarker. We conducted a four-stage study to identify the potential plasma miRNAs for CRC detection. In the initial screening phase, Exiqon panel (miRCURY-Ready-to-Use-PCR-Human-panel-I + II-V1.M) including 3 CRC pools and 1 normal controls (NCs) pool were applied to acquire miRNA profiles. In the training stage (30 CRC VS. 30 NCs) and testing stage (79 CRC VS. 76 NCs), quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to conduct candidate miRNA profiles. Then the identified miRNAs were verified in external validation stage (30 CRC VS. 26 NCs). Expression levels of identified miRNAs were assessed in tissue samples (24 pairs) and plasma exosomes (18 CRC VS. 18 NCs). Receiver operating characteristic (ROC) curves were constructed to evaluate the diagnostic accuracy. Seven miRNAs (miR-103a-3p, miR-127-3p, miR-151a-5p, miR-17-5p, miR-181a-5p, miR-18a-5p and miR-18b-5p) were significantly overexpressed in CRC compared with NCs. Area under the ROC curve of the seven-miRNA signature was 0.762, 0.824 and 0.895 for the training, testing and the external validation stages, respectively. Additionally, miR-103a-3p, miR-127-3p, miR-17-5p and miR-18a-5p were discovered significantly up-regulated in CRC tissues; while miR-17-5p, miR-181a-5p, miR-18a-5p and miR-18b-5p were significantly elevated in CRC plasma exosomes. In conclusion, we established a seven-miRNA signature in the peripheral plasma for CRC detection.

The Network of Non-coding RNAs in Cancer Drug Resistance

Non-coding RNAs (ncRNAs) have been implicated in most cellular functions. The disruption of their function through somatic mutations, genomic imprinting, transcriptional and post-transcriptional regulation, plays an ever-increasing role in cancer development. ncRNAs, including notorious microRNAs, have been thus proposed to function as tumor suppressors or oncogenes, often in a context-dependent fashion. In parallel, ncRNAs with altered expression in cancer have been reported to exert a key role in determining drug sensitivity or restoring drug responsiveness in resistant cells. Acquisition of resistance to anti-cancer drugs is a major hindrance to effective chemotherapy and is one of the most important causes of relapse and mortality in cancer patients. For these reasons, non-coding RNAs have become recent focuses as prognostic agents and modifiers of chemo-sensitivity. This review starts with a brief outline of the role of most studied non-coding RNAs in cancer and then highlights the modulation of cancer drug resistance via known ncRNAs based mechanisms. We identified from literature 388 ncRNA-drugs interactions and analyzed them using an unsupervised approach. Essentially, we performed a network analysis of the non-coding RNAs with direct relations with cancer drugs. Within such a machine-learning framework we detected the most representative ncRNAs-drug associations and groups. We finally discussed the higher integration of the drug-ncRNA clusters with the goal of disentangling effectors from downstream effects and further clarify the involvement of ncRNAs in the cellular mechanisms underlying resistance to cancer treatments.

miR-140-5p inhibits the proliferation and enhances the efficacy of doxorubicin to breast cancer stem cells by targeting Wnt1

MicroRNAs (miRNAs) are a group of small non-coding single-stranded RNAs molecules, the dysregulation of which plays a critical role in the initiation and biological progression of malignancies. The current study demonstrated that miR-140-5p was frequently downregulated in breast cancer stem cells (BCSCs), and miR-140-5p mimics could inhibit the proliferation of BCSCs. Moreover, Wnt1 was a direct target of miR-140-5p, as was proved by luciferase reporter assays. miR-140-5p mimics could downregulate the wnt1 mRNA and protein levels in MCF-7 and MDA-MB-231 cells. Furthermore, miR-140 mimics could enhance the sensitivity of BCSCs to doxorubicin (Dox) through the Wnt1/ABCB1 pathway both in vitro and vivo. Our findings have presented a novel miRNA-mediated regulatory network for BCSCs, which may provide a potential therapeutic target for breast cancer.

MiR-206 inhibits proliferation and migration of prostate cancer cells by targeting CXCL11

BACKGROUND

Our study was aimed at detecting the expression levels of miR-206 in prostate cancer (PCa) tissues and PCa cell lines, and exploring the potential functions of miR-206 by targeting chemokine ligand 11 (CXCL11).

METHODS

RT-qPCR was applied to detect the expressions of miR-206 and CXCL11 in PCa tissues and in PCa cell lines. Expression of the CXCL11 protein was detected using Western blot. After manipulating the expression of miR-206 and CXCL11 in PC-3 and DU-145 cells, the changes of cell proliferation and cell cycle were observed through cell counting kit-8 (CCK-8) and flow cytometry. Wound healing and transwell assay were conducted for cell migration and invasion examination in vitro. The luciferase reporter assay was applied to validate the association between miR-206 and CXCL11.

RESULTS

MiR-206 was significantly under-expressed in PCa tissues and in PCa cell lines. Up-regulation of miR-206 could inhibit proliferation, migration, invasion and induced G1/G0 arrest of PCa cells, and vice versa. MiR-206 bound to the 3'-UTR of CXCL11 and significantly repressed the luciferase activity. Overexpression of miR-206 decreased the expression level of CXCL11 significantly. CXCL11 mRNA and protein levels were significantly decreased in PCa cells. Downregulation of CXCL11 presented tumor-suppressing effects on PCa cells as miR-206 mimics did. And co-transfection miR-206 attenuated the tumor-promoting effects induced by CXCL11 overexpression.

CONCLUSION

Our current finding demonstrated that miR-206 negatively regulated PCa cell proliferation and migration, and arrested cell cycle by targeting CXCL11 as a tumor suppressor in prostate cancer.

miR-24-3p stimulates migration, invasion and proliferation of prostate cancer cells by targeting suppressor of cytokine signaling 6

Prostate cancer is among the most widespread malignancies affecting men in the world. Its aggressive evolution has been associated with altered expression of suppressor of cytokine signaling 6 (SOCS6) but very little is known about the mechanism by which this alteration occurs. The purpose of this study was to explore the role of SOCS6 in prostate cancer cells and the involvement of its regulating microRNA (miR), miR-24-3p. Prostate cancer cell lines were used to determine the transcription level of miR-24-3p and SOCS6 by quantitative reverse-transcriptase-polymerase chain reaction (qRT-PCR) and Western blot. Cell proliferation and cell migration assays were doneto determine the effect of miR-24-3p mimics and inhibitors on cell proliferation, invasion and migration. Luciferase reporter assay with SOCS6 3'-UTR was performed to confirm the control of SOCS6 expression by the miR. The results showed that miR-24-3p was up-regulated in prostate cancer cells whereas SOCS6 protein was downregulated. Overexpression of miR-24-3p in prostate cancer cells promoted cell proliferation, inhibited apoptosis, and increased cell migration and invasion. Luciferase reporter assays showed that SOCS6 is a direct target of its negative regulator miR-24-3p and overexpression of SOCS6 reverses the effects of miR-24-3p on the metastatic phenotype of prostate cancer cells. These results show case miR-24-3p up-regulation in prostate cancer and a mechanism for inhibition of SOCS6 expression. Thus, the miR-24-3p/SOCS6 pathway could be a relevant avenue for prostate cancer treatment.