MicroRNA Profile in Response to Doxorubicin Treatment in Breast Cancer

Direct detection of microRNA in liquid biopsies from single cancer spheroids

Exploring cancer heterogeneity is crucial for both understanding cancer and developing prognostic tools to monitor cancer progression during treatment through the liquid biopsy concept. Herein, a nanoparticle-based "dispersible electrodes" biosensor was used to detect ultra-low concentrations of microRNA-155 (miRNA-155) from a single breast cancer spheroid for the first time. The results from the sensor were comparable to the standard real-time polymerase chain reaction analysis, but in a much shorter detection time and without any sample purification or amplification. Owing to the unique ability of the sensor to measure biomarker expression from unaltered and undiluted cancer liquid biopsy from a single cancer spheroid, we then tracked dynamic changes in miRNA-155 expression in a single spheroid treated with the anti-cancer drug doxorubicin. The ability to track dynamic biomarker changes in a single cancer spheroid opens the door to understanding key biological processes such as response to treatment on the cellular and molecular levels, paving the way for adapting liquid biopsy insights to guide oncologists and more personalised treatment strategies.

The Overexpressed MicroRNAs miRs-182, 155, 493, 454, and U6 snRNA and Underexpressed let-7c, miR-328, and miR-451a as Potential Biomarkers in Invasive Breast Cancer and Their Clinicopathological Significance

INTRODUCTION

Breast cancer comprises the leading cause of cancer-related death in women. MicroRNAs (miRNAs) have emerged as important factors with concern to carcinogenesis and have potential for use as biomarkers.

METHODS

This study provides a comprehensive evaluation of the microRNA expression in invasive breast carcinoma of no special type tissues compared with benign tissues via large-scale screening and the candidate-specific validation of 15 miRNAs and U6 snRNA applying qPCR and the examination of clinicopathological data.

RESULTS

Of the six downregulated miRNAs, let-7c was identified as the most promising miRNA biomarker and its lower expression was linked with Ki-67 positivity, luminal B versus luminal A samples, multifocality, lymph node metastasis, and inferior PFS. Of the 9 upregulated sncRNAs, the data on U6 snRNA, miR-493 and miR-454 highlighted their potential oncogenic functions. An elevated U6 snRNA expression was associated with the tumor grade, Ki-67 positivity, luminal B versus A samples, lymph node metastasis, and worsened PFS (and OS) outcomes. An elevated miR-454 expression was detected in higher grades, Ki-67 positive and luminal B versus A samples. Higher miR-493 levels were noted for the tumor stage (and grade) and worse patient outcomes (PFS, OS). The data also suggested that miR-451a and miR-328 may have tumor suppressor roles, and miR-182 and miR-200c pro-oncogenic functions, while the remaining sncRNAs did not evince any significant associations.

CONCLUSION

We showed particular microRNAs and U6 snRNA as differentially expressed between tumors and benign tissues and associated with clinicopathological parameters, thus potentially corresponding with important roles in breast carcinogenesis. Their importance should be further investigated and evaluated in follow-up studies to reveal their potential in clinical practice.

INTRODUCTION

Breast cancer comprises the leading cause of cancer-related death in women. MicroRNAs (miRNAs) have emerged as important factors with concern to carcinogenesis and have potential for use as biomarkers.

METHODS

This study provides a comprehensive evaluation of the microRNA expression in invasive breast carcinoma of no special type tissues compared with benign tissues via large-scale screening and the candidate-specific validation of 15 miRNAs and U6 snRNA applying qPCR and the examination of clinicopathological data.

RESULTS

Of the six downregulated miRNAs, let-7c was identified as the most promising miRNA biomarker and its lower expression was linked with Ki-67 positivity, luminal B versus luminal A samples, multifocality, lymph node metastasis, and inferior PFS. Of the 9 upregulated sncRNAs, the data on U6 snRNA, miR-493 and miR-454 highlighted their potential oncogenic functions. An elevated U6 snRNA expression was associated with the tumor grade, Ki-67 positivity, luminal B versus A samples, lymph node metastasis, and worsened PFS (and OS) outcomes. An elevated miR-454 expression was detected in higher grades, Ki-67 positive and luminal B versus A samples. Higher miR-493 levels were noted for the tumor stage (and grade) and worse patient outcomes (PFS, OS). The data also suggested that miR-451a and miR-328 may have tumor suppressor roles, and miR-182 and miR-200c pro-oncogenic functions, while the remaining sncRNAs did not evince any significant associations.

CONCLUSION

We showed particular microRNAs and U6 snRNA as differentially expressed between tumors and benign tissues and associated with clinicopathological parameters, thus potentially corresponding with important roles in breast carcinogenesis. Their importance should be further investigated and evaluated in follow-up studies to reveal their potential in clinical practice.

Insights into molecular mechanisms of chemotherapy resistance in cancer

Cancer heterogeneity poses a significant hurdle to the successful treatment of the disease, and is being influenced by genetic inheritance, cellular and tissue biology, disease development, and response to therapy. While chemotherapeutic drugs have demonstrated effectiveness, their efficacy is impeded by challenges such as presence of resilient cancer stem cells, absence of specific biomarkers, and development of drug resistance. Often chemotherapy leads to a myriad of epigenetic, transcriptional and post-transcriptional alterations in gene expression as well as changes in protein expression, thereby leading to massive metabolic reprogramming. This review seeks to provide a detailed account of various transcriptional regulations, proteomic changes, and metabolic reprogramming in various cancer models in response to three primary chemotherapeutic interventions, docetaxel, carboplatin, and doxorubicin. Discussing the molecular targets of some of these regulatory events and highlighting their contribution in sensitivity to chemotherapy will provide insights into drug resistance mechanisms and uncover novel perspectives in cancer treatment.

Potential biomarkers in breast cancer drug development: application of the biomarker qualification evidentiary framework

Breast cancer treatments have evolved rapidly, and clinically meaningful biomarkers have been used to guide therapy. These biomarkers hold utility within the drug development process to increase the efficiency and effectiveness. To this purpose, the US FDA developed an evidentiary framework. Literature searches conducted of literature published between 2016 and 2022 identified biomarkers in breast cancer. These biomarkers were reviewed for drug development utility through the biomarker qualification evidentiary framework. In the breast cancer setting, several promising biomarkers (ctDNA, Ki-67 and PIK3CA) were identified. There is a need for increased transparency regarding the requirements for qualification of specific biomarkers and increased awareness of the processes involved in biomarker qualification.

Novel Siglec-15-Sia axis inhibitor leads to colorectal cancer cell death by targeting miR-6715b-3p and oncogenes

Siglecs are well known immunotherapeutic targets in cancer. Current checkpoint inhibitors have exhibited limited efficacy, prompting a need for novel therapeutics for targets such as Siglec-15. Presently, small molecule inhibitors targeting Siglec-15 are not explored alongside characterised regulatory mechanisms involving microRNAs in CRC progression. Therefore, a small molecule inhibitor to target Siglec-15 was elucidated in vitro and microRNA mediated inhibitor effects were investigated. Our research findings demonstrated that the SHG-8 molecule exerted significant cytotoxicity on cell viability, migration, and colony formation, with an IC50 value of approximately 20µM. SHG-8 exposure induced late apoptosis in vitro in SW480 CRC cells. Notably, miR-6715b-3p was the most upregulated miRNA in high-throughput sequencing, which was also validated via RT-qPCR. MiR-6715b-3p may regulate PTTG1IP, a potential oncogene which was validated via RT-qPCR and in silico analysis. Additionally, molecular docking studies revealed SHG-8 interactions with the Siglec-15 binding pocket with the binding affinity of -5.4 kcal/mol, highlighting its role as a small molecule inhibitor. Importantly, Siglec-15 and PD-L1 are expressed on mutually exclusive cancer cell populations, suggesting the potential for combination therapies with PD-L1 antagonists.

Identification of Gender- and Subtype-Specific Gene Expression Associated with Patient Survival in Low-Grade and Anaplastic Glioma in Connection with Steroid Signaling

Simple Summary

Gliomas are primary brain tumors that are initially slow growing but progress to be more aggressive and, ultimately, fatal within a few years. They are more common in men than in women, suggesting a protective role for female hormones. By analyzing patient data collected in the public TGCA-LGG database, we have demonstrated a link between the expression level of key steroid biosynthesis enzymes or hormone receptors with patient survival, in ways that are dependent on gender and molecular subtype. We also determined the genes which expression associated with these actors of steroid signaling and the functions they perform, to decipher the mechanisms underlying gender-dependent differences. Together, these results establish, for the first time, the involvement of hormones in low-grade and anaplastic gliomas and provide clues for refining their classification and, thus, facilitating more personalized management of patients.

Abstract

Low-grade gliomas are rare primary brain tumors, which fatally evolve to anaplastic gliomas. The current treatment combines surgery, chemotherapy, and radiotherapy. If gender differences in the natural history of the disease were widely described, their underlying mechanisms remain to be determined for the identification of reliable markers of disease progression. We mined the transcriptomic and clinical data from the TCGA-LGG and CGGA databases to identify male-over-female differentially expressed genes and selected those associated with patient survival using univariate analysis, depending on molecular characteristics (IDH wild-type/mutated; 1p/19q codeleted/not) and grade. Then, the link between the expression levels (low or high) of the steroid biosynthesis enzyme or receptors of interest and survival was studied using the log-rank test. Finally, a functional analysis of gender-specific correlated genes was performed. HOX-related genes appeared to be differentially expressed between males and females in both grades, suggesting that a glioma could originate in perturbation of developmental signals. Moreover, aromatase, androgen, and estrogen receptor expressions were associated with patient survival and were mainly related to angiogenesis or immune response. Therefore, consideration of the tight control of steroid hormone production and signaling seems crucial for the understanding of glioma pathogenesis and emergence of future targeted therapies.

The Role of miRNAs in the Resistance of Anthracyclines in Breast Cancer: A Systematic Review

Breast cancer has been reported as the most common cancer in women globally, with 2.26 million new cases in 2020. While anthracyclines are the first-line drug for breast cancer, they cause a variety of adverse reactions and drug resistance, especially for triple-negative breast cancer, which can lead to poor prognosis, high relapse, and mortality rate. MicroRNAs (miRNAs) have been shown to be important in the initiation, development and metastasis of malignancies and their abnormal transcription levels may influence the efficacy of anthracyclines by participating in the pathologic mechanisms of breast cancer. Therefore, it is essential to understand the exact role of miRNAs in the treatment of breast cancer with anthracyclines. In this review, we outline the mechanisms and signaling pathways involved in miRNAs in the treatment of breast cancer using anthracyclines. The role of miRNA in the diagnosis, prognosis and treatment of breast cancer patients is discussed, along with the involvement of miRNAs in chemotherapy for breast cancer.

miR-197-5p increases Doxorubicin-mediated anticancer cytotoxicity of HT1080 fibrosarcoma cells by decreasing drug efflux

Doxorubicin (Dox) is one of the most used drugs in the treatment of Soft tissue sarcoma. However, acquired resistance linked with poor survival and numerous side effects are the major challenges. Meanwhile, miRNAs are reported to influence the chemotherapeutic responses. However, there is hardly any evidence on the involvement of tumor-suppressive miR-197 reported in our previous study in augmenting the sensitivity of fibrosarcoma cells to Dox. Therefore, in this study, we intend to decipher if miR-197-5p combined with Dox could increase the anticancer cytotoxicity. For this, we evaluated the antitumorigenic effects of Dox and miR-197-5p individually and in combination by performing a series of molecular assays. We noticed that the sub-lethal concentration of miR-197-5p markedly enhanced the sensitivity of HT1080 fibrosarcoma cells to Dox by promoting apoptosis and G2/M cell cycle arrest. We also observed miR-197-5p sensitizes HT1080 cells to Dox by increasing drug influx, possibly due to suppression of MDR genes (ABCC1, MVP). Moreover, we found that KIAA0101, a target of miR-197-5p is inhibited by Dox, which is further repressed when treated in combination with miRNA. We also observed a marked upregulation of p53, known to be negatively correlated with KIAA0101 in Dox and miR-197-5p combination treatment compared to Dox alone. Taken together, our study revealed that Dox chemotherapy in combination with miR-197-5p could overcome the problem of drug efflux and enhance its antitumor effects on fibrosarcoma.

Breast cancer: Muscarinic receptors as new targets for tumor therapy

The development of breast cancer is a complex process that involves the participation of different factors. Several authors have demonstrated the overexpression of muscarinic acetylcholine receptors (mAChRs) in different tumor tissues and their role in the modulation of tumor biology, positioning them as therapeutic targets in cancer. The conventional treatment for breast cancer involves surgery, radiotherapy, and/or chemotherapy. The latter presents disadvantages such as limited specificity, the appearance of resistance to treatment and other side effects. To prevent these side effects, several schedules of drug administration, like metronomic therapy, have been developed. Metronomic therapy is a type of chemotherapy in which one or more drugs are administered at low concentrations repetitively. Recently, two chemotherapeutic agents usually used to treat breast cancer have been considered able to activate mAChRs. The combination of low concentrations of these chemotherapeutic agents with muscarinic agonists could be a useful option to be applied in breast cancer treatment, since this combination not only reduces tumor cell survival without affecting normal cells, but also decreases pathological neo-angiogenesis, the expression of drug extrusion proteins and the cancer stem cell fraction. In this review, we focus on the previous evidences that have positioned mAChRs as relevant therapeutic targets in breast cancer and analyze the effects of administering muscarinic agonists in combination with conventional chemotherapeutic agents in a metronomic schedule.

Combination of Metformin, Sodium Oxamate and Doxorubicin Induces Apoptosis and Autophagy in Colorectal Cancer Cells via Downregulation HIF-1α

Colorectal cancer (CRC) is the third leading cause of cancer-related death worldwide in both sexes. Current therapies include surgery, chemotherapy, and targeted therapy; however, prolonged exposure to chemical agents induces toxicity in patients and drug resistance. So, we implemented a therapeutic strategy based on the combination of doxorubicin, metformin, and sodium oxamate called triple therapy (Tt). We found that Tt significantly reduced proliferation by inhibiting the mTOR/AKT pathway and promoted apoptosis and autophagy in CRC derived cells compared with doxorubicin. Several autophagy genes were assessed by western blot; ULK1, ATG4, and LC3 II were overexpressed by Tt. Interestingly, ULK1 was the only one autophagy-related protein gradually overexpressed during Tt administration. Thus, we assumed that there was a post-transcriptional mechanism mediating by microRNAs that regulate UKL1 expression during autophagy activation. Through bioinformatics approaches, we ascertained that ULK1 could be targeted by mir-26a, which is overexpressed in advanced stages of CRC. In vitro experiments revealed that overexpression of mir-26a decreased significantly ULK1, mRNA, and protein expression. Contrariwise, the Tt recovered ULK1 expression by mir-26a decrease. Due to triple therapy repressed mir-26a expression, we hypothesized this drug combination could be involved in mir-26a transcription regulation. Consequently, we analyzed the mir-26a promoter sequence and found two HIF-1α transcription factor recognition sites. We developed two different HIF-1α stabilization models. Both showed mir-26a overexpression and ULK1 reduction in hypoxic conditions. Immunoprecipitation experiments were performed and HIF-1α enrichment was observed in mir-26a promoter. Surprisingly, Tt diminished HIF-1α detection and restored ULK1 mRNA expression. These results reveal an important regulation mechanism controlled by the signaling that activates HIF-1α and that in turn regulates mir-26a transcription.

The role of miRNAs and lncRNAs in conferring resistance to doxorubicin

Doxorubicin is a chemotherapeutic agent that inhibits topoisomerase II, intercalates within DNA base pairs and results in oxidative DNA damage, thus inducing cell apoptosis. Although it is effective in the treatment of a wide range of human cancers, the emergence of resistance to this drug can increase tumour growth and impact patients' survival. Numerous molecular mechanisms and signalling pathways have been identified that induce resistance to doxorubicin via stimulation of cell proliferation, cell cycle switch and preclusion of apoptosis. A number of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) have also been identified that alter sensitivity to doxorubicin. Understanding the particular impact of these non-coding RNAs in conferring resistance to doxorubicin has considerable potential to improve selection of chemotherapeutic regimens for cancer patients. Moreover, modulation of expression of these transcripts is a putative strategy for combating resistance. In the current paper, the influence of miRNAs and lncRNAs in the modification of resistance to doxorubicin is discussed.

Negative Regulation of ULK1 by microRNA-106a in Autophagy Induced by a Triple Drug Combination in Colorectal Cancer Cells In Vitro

Colorectal cancer (CRC) is among the top three most deadly cancers worldwide. The survival rate for this disease has not been reduced despite the treatments, the reason why the search for therapeutic alternatives continues to be a priority issue in oncology. In this research work, we tested our successful pharmacological combination of three drugs, metformin, doxorubicin, and sodium oxamate (triple therapy, or TT), as an autophagy inducer. Firstly, we employed western blot (WB) assays, where we observed that after 8 h of stimulation with TT, the proteins Unc-51 like autophagy activating kinase 1(ULK1), becline-1, autophagy related 1 protein (Atg4), and LC3 increased in the CRC cell lines HCT116 and SW480 in contrast to monotherapy with doxorubicin. The overexpression of these proteins indicated the beginning of autophagy flow through the activation of ULK1 and the hyperlipidation of LC3 at the beginning of this process. Moreover, we confirm that ULK1 is a bona fide target of hsa-miR-106a-5p (referred to from here on as miR-106a) in HCT116. We also observed through the GFP-LC3 fusion protein that in the presence of miR-106a, the accumulation of autophagy vesicles in cells stimulated with TT is inhibited. These results show that the TT triggered autophagy to modulate miR-106a/ULK1 expression, probably affecting different cellular pathways involved in cellular proliferation, survivance, metabolic maintenance, and cell death. Therefore, considering the importance of autophagy in cancer biology, the study of miRNAs that regulate autophagy in cancer will allow a better understanding of malignant tumors and lead to the development of new disease markers and therapeutic strategies.

Differences of time-dependent microRNA expressions in breast cancer cells

MicroRNA (miRNA) expression is a dynamic process in the cell, and the proper time period for post-transcriptional regulation might be critical due to the gene-on/-off expression times of the cell. Here, we investigated the effect of different time-points on proliferation, invasion and miRNA expression profiles of human breast cancer cell lines MCF-7 (non-metastatic, epithelium-like breast cancer cell line with oestrogen receptor (ER) positive (+) and human breast cancer cell lines MDA-MB-435 (metastatic, invasive, ER negative (-). For this purpose, MCF-7 and MDA-MB-435 cells were seeded different number in E-plate 16 for proliferation experiment using an electrical impedance-based real-time cell analyzer system (RTCA) for 168 h. Similarly, invasion potential of MCF-7 and MDA-MB-435 were determined by RTCA for 90 h. Total RNAs including miRNAs were isolated at 2, 4, 6, 12, 24, 48 h from the MCF-7 and MDA-MB-435 cells. Afterward, the quantitative 84 miRNA expressions of MCF-7 and MDA-MB-435 were analyzed by Fluidigm Microfluidic 96.96 Dynamic Array. The results of these study demonstrated that both proliferation potential and invasion capacity of MDA-MB-435 is higher than MCF-7 as time-dependent manner. Furthermore, we detected that up/down expressions of 32 miRNAs at all time points in MDA-MB-435 compared to MCF-7 (at least ten-fold increased). Because of the high number of miRNAs, we more closely evaluated the expression of six of them (miR-100-5p, miR-29a-3p, miR-130a-3p, miR-10a-5p, miR-10b-5p, miR-203a), and determined that their levels were dramatically changed by at least 50-fold at different time points of the experiment (p < 0.01). The expression levels of five of these miRNAs (miR-100-5p, miR-10a-5p, miR-10b-5p, miR-130a-3p, and miR-29a-3p) started to increase from the fourth hour and continued to increase until the 48th hour in MDA-MB-435 cells compared to MCF-7 cells (p < 0.01). Simultaneously, the expression of one of these miRNAs (miR-203a) decreased from the sixth hour to the 48th hour in MDA-MB-435 as compared to MCF-7. We determined pathways associated with target genes using mirPath - DIANA TOOLS. Small RNAs including miRNA are essential regulatory molecules for gene expressions. In the literature, gene expressions have been published as burst and pulse in the form of discontinuous transcription. The data of the research suggested that time-dependent changes of miRNA expressions can be affected target gene transcriptional fluctuations in breast cancer cell and can be base for the further studies.

miRNA Expression Analysis: Cell Lines HCC1500 and HCC1937 as Models for Breast Cancer in Young Women and the miR-23a as a Poor Prognostic Biomarker

PURPOSE

The study of breast cancer nearly always involves patients close to menopause or older. Therefore, young patients are mostly underrepresented. Our aim in this study was to demonstrate biological differences in breast cancer of young people using as a model available cell lines derived from people with breast cancer younger than 35 years.

METHODS

Global miRNA expression was analyzed in breast cancer cells from young (HCC1500, HCC1937) and old patients (MCF-7, MDA-MB-231, HCC1806, and MDA-MB-468). In addition, it was compared with same type of results from patients.

RESULTS

We observed a differential profile for 155 miRNAs between young and older cell lines. We identified a set of 24 miRNA associated with aggressiveness that were regulating pluripotency of stem cell-related pathways. Combining the miRNA expression data from cell lines and breast cancer patients, 132 miRNAs were differently expressed between young and old samples, most of them previously found in cell lines. MiR-23a-downregulation was also associated with poor survival in young patients.

CONCLUSIONS

Our results suggest that HCC1500 and HCC1937 cell lines could be suitable cellular models for breast cancer affecting young women. The miR-23a-downregulation could have a potential role as a poor prognosis biomarker in this age group.

MiR-548c-3p inhibits the proliferation, migration and invasion of human breast cancer cell by targeting E2F3

MiR-548 has been reported to be involved in a variety of tumor processes, but its function in breast cancer remains unclear. In this study, we found that miR-548 was low expressed in breast cancer tissues and cells compared with normal control. We then examined whether up-regulation of miR-548 could improve the progression of breast cancer. Our results indicate that up-regulation of miR-548 significantly inhibits cell proliferation, migration andinvasion, and induces apoptosis in breast cancer cells. Further studies showed that miR-548 could specifically inhibit E2F3 expression. Moreover, rescue test showed that up-regulation of E2F2 could reverse the effect of miR-548 on proliferation, migration, invasion and apoptosis of breast cancer cells. In general, miR-548 could improve the progression of breast cancer. By targeting E2F2, which may make a potential target for the treatment of breast cancer.

Large miRNA survival analysis reveals a prognostic four-biomarker signature for triple negative breast cancer

Triple negative breast cancer (TNBC) is currently the only major breast tumor subtype without effective targeted therapy and, as a consequence, usually presents a poor outcome. Due to its more aggressive phenotype, there is an urgent clinical need to identify novel biomarkers that discriminate individuals with poor prognosis. We hypothesize that miRNAs can be used to this end because they are involved in the initiation and progression of tumors by altering the expression of their target genes. To identify a prognostic biomarker in TNBC, we analyzed the miRNA expression of a cohort composed of 185 patients diagnosed with TNBC using penalized Cox regression models. We identified a four-biomarker signature based on miR-221, miR-1305, miR-4708, and RMDN2 expression levels that allowed for the subdivision of TNBC into high- or low-risk groups (Hazard Ratio – HR = 0.32; 95% Confidence Interval - CI = 0.11–0.91; p = 0.03) and are also statistically associated with survival outcome in subgroups of postmenopausal status (HR = 0.19; 95% CI = 0.04–0.90; p= 0.016), node negative status (HR = 0.12; 95% CI = 0.01–1.04; p = 0.026), and tumors larger than 2cm (HR = 0.21; 95% CI = 0.05–0.81; p = 0.021). This four-biomarker signature was significantly associated with TNBC as an independent prognostic factor for survival.

Major obstacles to doxorubicin therapy: Cardiotoxicity and drug resistance

Background

Doxorubicin is one of the most commonly prescribed and time-tested anticancer drugs. Although being considered as a first line drug in different types of cancers, the two main obstacles to doxorubicin therapy are drug-induced cardiotoxicity and drug resistance.

Method

The study utilizes systemic reviews on publications of previous studies obtained from scholarly journal databases including PubMed, Medline, Ebsco Host, Google Scholar, and Cochrane. The study utilizes secondary information obtained from health organizations using filters and keywords to sustain information relevancy. The study utilizes information retrieved from studies captured in the peer-reviewed journals on “doxorubicin-induced cardiotoxicity” and “doxorubicin resistance.”

Discussion and results

The exact mechanisms of cardiotoxicity are not known; various hypotheses are studied. Doxorubicin can lead to free radical generation in various ways. The commonly proposed underlying mechanisms promoting doxorubicin resistance are the expression of multidrug resistance proteins as well as other causes.

Conclusion

In this review, we have described the major obstacles to doxorubicin therapy, doxorubicin-induced cardiotoxicity as well as the mechanisms of cancer drug resistance and in following the treatment failures.

The miRNA-449 family mediates doxorubicin resistance in triple-negative breast cancer by regulating cell cycle factors

The mechanisms of chemotherapy resistance in triple negative breast cancer remain unclear, and so, new molecules which might mediate this resistance could optimize treatment response. Here we analyzed the involvement of the miRNA-449 family in the response to doxorubicin. The cell viability, cell-cycle phases, and the expression of in silico target genes and proteins of sensitive/resistant triple negative breast cancer cell lines were evaluated in response to doxorubicin treatment and after gain/loss of miRNAs-449 function achieved by transient transfection. Triple negative breast cancer patients were selected for ex vivo experiments and to evaluate gene and miRNAs expression changes after treatment, as well as survival analysis by Kaplan-Meier. Doxorubicin treatment upregulated miRNAs-449 and DNA-damage responder factors E2F1 and E2F3 in triple negative breast cancer sensitive breast cancer cells, while expression remained unaltered in resistant ones. In vitro overexpression of miRNAs-449 sensitized cells to the treatment and significantly reduced the resistance to doxorubicin. These changes showed also a strong effect on cell cycle regulation. Finally, elevated levels of miRNA-449a associated significantly with better survival in chemotherapy-treated triple negative breast cancer patients. These results reveal for the first time the involvement of the miRNA-449 family in doxorubicin resistance and their predictive and prognostic value in triple negative breast cancer patients.

The inhibitive effect of sh-HIF1A-AS2 on the proliferation, invasion, and pathological damage of breast cancer via targeting miR-548c-3p through regulating HIF-1α/VEGF pathway in vitro and vivo

Background

Breast cancer (BC) has been the commonest malignant tumor with a low survival rate among woman. Long non-coding RNA hypoxia-inducible factor-1 alpha antisense RNA-2 (HIF1A-AS2) was correlated with various cancers.

Purpose

The study aimed to investigate the roles and related underlying molecular mechanisms of HIF1A-AS2 in BC.

Material and methods

Target relationships were speculated by Targetscan 7.0 and confirmed by dual luciferase reporter assay. Proteins levels were monitored by RT-qPCR, Western blot and immunohistochemistry assays. CCK-8 assay, SA-β-gal staining and transwell assay were used to detect proliferation, senescence and invasion, respectively. Xenograft nude mice were put into use to evaluate the tumor growth and motility.

Results

The present study exhibited that HIF1A-AS2 and hypoxia-inducible factor-1 alpha (HIF-1α) were upregulated while miR-548c-3p was downregulated in MDA-MB-231, MCF-7, ZR-75-1, and BT-549 BC cell lines. Bioinformatics analysis showed HIF1A-AS2 and HIF-1α were two targets of miR-548c-3p, and the target relationship was further confirmed by dual luciferase reporter assay. Moreover, knockdown of HIF1A-AS2 by shRNA (sh-HIF1A-AS2) markedly elevated miR-548c-3p level, and the enhanced miR-548c-3p noticeably suppressed cell proliferation, invasion, and epithelial–mesenchymal transition, and promoted senescence in vitro. In addition, overexpression of HIF-1α promoted MCF-7 cell invasion. Intriguingly, low expression of HIF1A-AS2 reduced HIF-1α level by upregulating the expression of miR-548c-3p. Furthermore, experiment in xenograft nude mice has indicated that sh-HIF1A-AS2 inhibited tumor growth and motility by targeting miR-548c-3p through regulating HIF-1α/vascular endothelial growth factor (VEGF) pathway in vivo.

Conclusion

The inhibitive effect of HIF-1α/VEGF pathway by sh-HIF1A-AS2 through targeting miR-548c-3p plays crucial regulatory roles in BC. Therefore, designing targeted drugs against HIF1A-AS2 provides a new direction for the treatment of BC.

Gene and MicroRNA Perturbations of Cellular Response to Pemetrexed Implicate Biological Networks and Enable Imputation of Response in Lung Adenocarcinoma

Pemetrexed is indicated for non-small cell lung carcinoma and mesothelioma, but often has limited efficacy due to drug resistance. To probe the molecular mechanisms underlying chemotherapeutic response, we performed mRNA and microRNA (miRNA) expression profiling of pemetrexed treated and untreated lymphoblastoid cell lines (LCLs) and applied a hierarchical Bayesian method. We identified genetic variation associated with gene expression in human lung tissue for the most significant differentially expressed genes (Benjamini-Hochberg [BH] adjusted p < 0.05) using the Genotype-Tissue Expression data and found evidence for their clinical relevance using integrated molecular profiling and lung adenocarcinoma survival data from The Cancer Genome Atlas project. We identified 39 miRNAs with significant differential expression (BH adjusted p < 0.05) in LCLs. We developed a gene expression based imputation model of drug sensitivity, quantified its prediction performance, and found a significant correlation of the imputed phenotype generated from expression data with survival time in lung adenocarcinoma patients. Differentially expressed genes (MTHFD2 and SUFU) that are putative targets of differentially expressed miRNAs also showed differential perturbation in A549 fusion lung tumor cells with further replication in A549 cells. Our study suggests pemetrexed may be used in combination with agents that target miRNAs to increase its cytotoxicity.

Increased expression of miR-155 and miR-222 is associated with lymph node positive status

Identification of prognostic molecular markers of breast cancer is extremely important. The spreading out of the primary breast tumour cells to the lymphatic system is at the forefront of symbolising the first signs of distant organ metastasis. Deregulated genes in breast cancer tissues that spread to lymph nodes may show early predictive molecular markers. In the present study, we selected five microRNAs, which play a key function in the invasion-metastasis cascade. We investigated the levels of microRNAs in 80 paired samples of BC and matched adjoining tissues, and we examined the potential relationships between microRNA levels and positive lymph node status. Our results attest that three microRNAs (miR-21, miR-155, miR-222) were significantly up-regulated, whilst miR-205 was substantially down-regulated in BC tissues in relation to normal adjoining tissues in a heterogeneous patient cohort. The high levels of two microRNAs, miR-155 and miR-222, showed a statistical relation with the positive lymph node status, especially in patients that had triple negative BC. Conversely, miR-155 was substantially down-regulated in tumour tissues of patients who received preoperative neoadjuvant chemotherapy (NAC) compared with tumour tissues of patients without NAC in cohorts sub-classified to lymph node positive status. Our findings show evidence that the miR-155 and the miR-222 can be defined as molecular markers in regards to cancer patients to prognosticate spread to the lymph node. They also showed that the miR-155 could have crucial significances in BC treatment.

Curcumin induces apoptotic cell death in human pancreatic cancer cells via the miR-340/XIAP signaling pathway

The natural compound curcumin has previously been reported to inhibit pancreatic cancer cell growth. However, the underlying molecular mechanisms underlying this effect remain unclear. Results from the present study demonstrate that the miR-340/X-linked inhibitor of apoptosis (XIAP) signaling pathway mediates curcumin-induced pancreatic cancer cell apoptosis. miR-340 was identified to be significantly upregulated following curcumin treatment. In addition, treatment with curcumin or miR-340 induced pancreatic cancer cell apoptosis, whereas silencing endogenous miR-340 significantly inhibited the proapoptotic effect of curcumin. A luciferase reporter assay and western blot analysis identified that the oncogene XIAP is a direct target of miR-340. Furthermore, curcumin treatment significantly reduced XIAP expression, an effect that was rescued by treatment with anti-miR-340. The results of the present study suggest that the miR-340/XIAP signaling pathway is a downstream target of curcumin that mediates its proapoptotic effects on pancreatic cancer cells. This may provide the basis for novel treatment strategies for patients with pancreatic cancer.

A microRNA signature associated with pathological complete response to novel neoadjuvant therapy regimen in triple-negative breast cancer

Neoadjuvant chemotherapy aims to improve the outcome of breast cancer patients, but only few would benefit from this treatment. Pathological complete response has been proposed as a surrogate marker for the prediction of long-term clinical benefits; however, 50%-85% patients have an unfavorable pathological complete response to chemotherapy. MicroRNAs are known biomarkers of breast cancer progression; nevertheless, their potential to identify patients with pathological complete response remains poorly understood. Here, we investigated whether a microRNA profile could be associated with pathological complete response in triple-negative breast cancer patients receiving 5-fluorouracil, adriamycin, cyclophosphamide-cisplatin/paclitaxel as a novel neoadjuvant chemotherapy. In the discovery cohort, the expression of 754 microRNAs was examined in tumors from 10 triple-negative breast cancer patients who achieved pathological complete response and 8 without pathological complete response using TaqMan Low-Density Arrays. Unsupervised hierarchical cluster analysis identified 11 microRNAs with significant differences between responder and no-responder patients (fold change ≥ 1.5; p < 0.05). The differential expression of miR-30a, miR-9-3p, miR-770, and miR-143-5p was validated in an independent group of 17 patients with or without pathological complete response. Moreover, Kaplan-Meier analysis showed that expression of these four microRNAs was associated with an increased disease-free survival. Gene ontology classification of predicted microRNA targets indicated that numerous genes are involved in pathways related to chemoresistance, such as vascular endothelial growth factor, focal adhesion kinase, WNT, ERbB, phosphoinositide 3-kinase, and AKT signaling. In summary, we identified a novel microRNA expression signature associated with pathological complete response in breast cancer. We propose that the four validated microRNAs could be used as molecular biomarkers of clinical response in triple-negative breast cancer patients with pathological complete response to neoadjuvant therapy.

The Antitumor Effect of Metformin Is Mediated by miR-26a in Breast Cancer

Metformin, a drug approved for diabetes type II treatment, has been associated with a reduction in the incidence of breast cancer and metastasis and increased survival in diabetic breast cancer patients. High levels of miR-26a expression have been proposed as one of the possible mechanisms for this effect; likewise, this miRNA has also been associated with survival/apoptosis processes in breast cancer. Our aim was to evaluate if miR-26a and some of its targets could mediate the effect of metformin in breast cancer. The viability of MDA-MB-231, MDA-MB-468, and MCF-7 breast cancer cell lines was evaluated with an MTT assay after ectopic overexpression and/or downregulation of miR-26a. Similarly, the expression levels of the miR-26a targets CASP3, CCNE2, ABL2, APAF1, XIAP, BCL-2, PTEN, p53, E2F3, CDC25A, BCL2L1, MCL-1, EZH2, and MTDH were assessed by quantitative polymerase chain reaction (PCR). The effect of metformin treatment on breast cancer cell viability and miR-26a, BCL-2, PTEN, MCL-1, EZH2, and MTDH modulation were evaluated. Wound healing experiments were performed to analyze the effect of miR-26a and metformin treatment on cell migration. MiR-26a overexpression resulted in a reduction in cell viability that was partially recovered by inhibiting it. E2F3, MCL-1, EZH2, MTDH, and PTEN were downregulated by miR-26a and the PTEN (phosphatase and tensin homolog) protein was also reduced after miR-26a overexpression. Metformin treatment reduced breast cancer cell viability, increased miR-26a expression, and led to a reduction in BCL-2, EZH2, and PTEN expression. miR-26a inhibition partly prevents the metformin viability effect and the PTEN and EZH2 expression reduction. Our results indicate that metformin effectively reduces breast cancer cell viability and suggests that the effects of the drug are mediated by an increase in miR-26a expression and a reduction of its targets, PTEN and EHZ2 Thus, the use of metformin in breast cancer treatment constitutes a promising potential breast cancer therapy.

Current state of phenolic and terpenoidal dietary factors and natural products as non-coding RNA/microRNA modulators for improved cancer therapy and prevention

The epigenetic regulation of cancer cells by small non-coding RNA molecules, the microRNAs (miRNAs), has raised particular interest in the field of oncology. These miRNAs play crucial roles concerning pathogenic properties of cancer cells and the sensitivity of cancer cells towards anticancer drugs. Certain miRNAs are responsible for an enhanced activity of drugs, while others lead to the formation of tumor resistance. In addition, miRNAs regulate survival and proliferation of cancer cells, in particular of cancer stem-like cells (CSCs), that are especially drug-resistant and, thus, cause tumor relapse in many cases. Various small molecule compounds were discovered that target miRNAs that are known to modulate tumor aggressiveness and drug resistance. This review comprises the effects of naturally occurring small molecules (phenolic compounds and terpenoids) on miRNAs involved in cancer diseases.

Non-canonical NF-κB pathway activation predicts outcome in borderline oestrogen receptor positive breast carcinoma

Background:

NF-κB signalling appears deregulated in breast tumours. The purpose of this study was to determine whether the non-canonical NF-κB pathway, is activated in oestrogen receptor positive (ER+) breast cancer, to identify any correlation between its activity and the clinico-pathological phenotype and to explore whether NF-κB2 and RelB subunits and/or any of their target genes might be used as a predictive marker.

Methods:

Two independent cohorts of ER+ early breast cancer patients treated with adjuvant endocrine therapy were included in the study. Activation of RelB and NF-κB2 subunits was determined in a training set of 121 patients by measuring DNA-binding activities in nuclear extracts from fresh frozen specimens by an ELISA-based assay. Samples of 15 ER− breast cancer patients were also included in the study. In a large validation cohort of 207 patients, nuclear immunostaining of RelB and NF-κB2 on formalin-fixed paraffin-embedded specimens was performed. Statistical correlation within clinico-pathological factors, disease-free survival (DFS) and overall survival (OS) was evaluated. Publicly available gene expression and survival data have been interrogated aimed to identify target genes.

Results:

Activation of NF-κB2 and RelB was found in 53.7 and 49.2% of the 121 ER+ tumours analysed, with similar levels to ER− breast tumours analysed in parallel for comparisons. In the validation cohort, we obtained a similar proportion of cases with activation of NF-κB2 and RelB (59.9 and 32.4%), with a 39.6% of co-activation. Multiplexing immunofluorescence in breast cancer tissue confirmed an inverse spatial distribution of ER with NF-κB2 and RelB nuclear expression in tumour cells. Interestingly, NF-κB2 and RelB mRNA expression was inversely correlated with ER gene (ESR1) levels (P<0.001, both) and its activation was significantly associated with worse DFS (P=0.005 and P=0.035, respectively) in ER+ breast cancer. Moreover, the co-activation of both subunits showed a stronger association with early relapse (P=0.002) and OS (P=0.001). Finally, higher expression of the non-canonical NF-κB target gene myoglobin was associated with a poor outcome in ER+ breast cancer (DFS, P<0.05).

Conclusions:

The non-canonical NF-κB pathway activation is inversely associated with oestrogen receptor expression in ER+ breast cancer and predicts poor survival in this subgroup. The myoglobin gene expression has been identified as a possible surrogate marker of the non-canonical NF-κB pathway activation in these tumours.

Comprehensive Expression Profiling and Functional Network Analysis of p53-Regulated MicroRNAs in HepG2 Cells Treated with Doxorubicin

Acting as a sequence-specific transcription factor, p53 tumor suppressor involves in a variety of biological processes after being activated by cellular stresses such as DNA damage. In recent years, microRNAs (miRNAs) have been confirmed to be regulated by p53 in several cancer types. However, it is still unclear how miRNAs orchestrate their regulation and function in p53 network after p53 activation in hepatocellular carcinoma (HCC). In this study, we used small RNA sequencing and systematic bioinformatic analysis to characterize the regulatory networks of differentially expressed miRNAs after the p53 activation in HepG2. Here, 33 miRNAs significantly regulated by p53 (12 up-regulated and 21 down-regulated) were detected between the doxorubicin-treated and untreated HepG2 cells in two biological replicates for small RNA sequencing and 8 miRNAs have been reported previously to be associated with HCC. Gene ontology (GO) and KEGG pathway enrichment analysis showed that 87.9% (29 out of 33) and 90.9% (30 out of 33) p53-regulated miRNAs were involved in p53-related biological processes and pathways with significantly low p-value, respectively. Remarkably, 18 out of 33 p53-regulated miRNAs were identified to contain p53 binding sites around their transcription start sites (TSSs). Finally, comprehensive p53-miRNA regulatory networks were constructed and analyzed. These observations provide a new insight into p53-miRNA co-regulatory network in the context of HCC.

MicroRNA-92a promotes growth, metastasis, and chemoresistance in non-small cell lung cancer cells by targeting PTEN

MicroRNA-92a (miR-92a) has been reported to play important roles in tumorigenesis of human various cancers. However, the roles and underlying molecular mechanism of miR-92a in non-small cell lung cancer (NSCLC) have not been totally elucidated. Therefore, the aims of this study were to determine the role of miR-92a and to elucidate its regulatory mechanism in NSCLC. We found that miR-92a was significantly upregulated in NSCLC tissues compared to matched adjacent normal lung tissues, and its expression is significantly associated with clinical characteristics of patients, including tumor, node, and metastasis (TNM) stage; tumor size; and lymph node metastasis (all P < 0.01). Function assays demonstrated that upregulation of miR-92a in NSCLC cells promoted cell proliferation, migration, and invasion, decreased apoptosis and caspase-3 activity, and enhanced chemoresistance of NSCLC cells, whereas downregulation of miR-92a showed the opposite effects. Moreover, phosphatase and tensin homolog (PTEN), a unique tumor suppressor gene, was confirmed as a direct target of miR-92a, and PTEN messenger RNA (mRNA) expression was decreased in NSCLC tissues and was inversely correlated with miR-92a. Downregulation of PTEN could mimic the same effects of miR-92a mimic in NSCLC cells and rescue the effects on NSCLC cells induced by miR-92a inhibitor. Taken together, these findings suggested that miR-92a could promote growth, metastasis, and chemoresistance in NSCLC cells at least partially by targeting PTEN.