MiR-27a modulates radiosensitivity of triple-negative breast cancer (TNBC) cells by targeting CDC27

Non-coding RNAs as modulators of radioresponse in triple-negative breast cancer: a systematic review

Triple-negative breast cancer (TNBC), characterized by high invasiveness, is associated with poor prognosis and elevated mortality rates. Despite the development of effective therapeutic targets for TNBC, systemic chemotherapy and radiotherapy (RdT) remain prevalent treatment modalities. One notable challenge of RdT is the acquisition of radioresistance, which poses a significant obstacle in achieving optimal treatment response. Compelling evidence implicates non-coding RNAs (ncRNAs), gene expression regulators, in the development of radioresistance. This systematic review focuses on describing the role, association, and/or involvement of ncRNAs in modulating radioresponse in TNBC. In adhrence to the PRISMA guidelines, an extensive and comprehensive search was conducted across four databases using carefully selected entry terms. Following the evaluation of the studies based on predefined inclusion and exclusion criteria, a refined selection of 37 original research articles published up to October 2023 was obtained. In total, 33 different ncRNAs, including lncRNAs, miRNAs, and circRNAs, were identified to be associated with radiation response impacting diverse molecular mechanisms, primarily the regulation of cell death and DNA damage repair. The findings highlighted in this review demonstrate the critical roles and the intricate network of ncRNAs that significantly modulates TNBC's responsiveness to radiation. The understanding of these underlying mechanisms offers potential for the early identification of non-responders and patients prone to radioresistance during RdT, ultimately improving TNBC survival outcomes.

Research progress on factors affecting the sensitivity of breast cancer to radiotherapy: a narrative review

Background and Objective

Radiation therapy (RT) is one of the important components of comprehensive treatment for breast cancer and has important value in improving the control rate of local areas, reducing the chance of recurrence and metastasis after breast cancer surgery, delaying disease progression, and improving the survival of breast cancer patients. The factors that affect the RT sensitivity of breast cancer are important. The above potential predictors of radiation efficacy can provide patients with a predictive method and therefore have significant value in clinical therapy. In this paper, we have summarised the predictive factors of radiotherapy sensitivity by reviewing recent research on breast cancer and focused on the following areas: tumor immune microenvironment (TIME), cancer stem cells, noncoding RNAs, signal transduction pathways, genes, etc. This review aims to provide theoretical basis and reference for improving the efficacy of radiotherapy and experimental individualized treatment of breast cancer.

Methods

We searched the Web of Science database to identify clinical studies published between 2010 and January 2024 that investigated radiotherapy sensitivity. The main findings of the validated studies were summarised.

Key Content and Findings

Improving the radiosensitivity of breast cancer is essential in the treatment of breast cancer. The radiosensitivity can be improved by modulating immune cells or immunomodulatory factors in the TIME, modulating signal transduction pathways, and other innovative combination therapy strategies. And we also summarized the predictive markers of breast cancer radiosensitivity.

Conclusions

In this paper, we reviewed the literature and summarized the newest research advances on the radiosensitivity of breast cancer patients. This review paper includes the following six aspects: the immune microenvironment, tumor stem cells, signaling pathways, regulation of gene/protein expression, small molecule drugs, and predictive markers for radiosensitivity.

Radiation therapy for triple-negative breast cancer: from molecular insights to clinical perspectives

INTRODUCTION

Triple-negative breast cancer (TNBC) lacks three common receptors, making traditional treatments less effective. This review highlights the importance of radiotherapy and emerging therapeutic strategies to enhance treatment outcomes in TNBC.

AREAS COVERED

We conducted a literature search on PubMed for publications from 2000 to 2023 to discuss the critical role of radiotherapy in managing TNBC, emphasizing its applications from locoregional control to improving survival rates. The review explores molecular mechanisms underlying TNBC's radiotherapy response, including DNA damage repair and apoptosis, with a focus on BRCA1/2 mutations and Poly (ADP-ribose) polymerase (PARP) inhibition. We summarize preclinical and clinical research on radiosensitization strategies, from gene-targeted therapies to immunotherapy combinations, and the impact of post-mastectomy radiation therapy on locoregional control. The potential of personalized treatment approaches, integrating molecular profiling, targeted radiosensitizers, and the synergistic effects of radiotherapy with immunotherapy, is also discussed.

EXPERT OPINION

Future TNBC treatment strategies should focus on precision medicine, integrating immunotherapy, developing novel radiosensitizers, and targeting biological pathways to overcome radioresistance. The integration of radiomics and artificial intelligence offers promising avenues for enhancing treatment personalization and efficacy, aiming to improve patient outcomes in TNBC.

Molecular subtypes of breast cancer predicting clinical benefits of radiotherapy after breast-conserving surgery: a propensity-score-matched cohort study

BACKGROUND

Based on the molecular expression of cancer cells, molecular subtypes of breast cancer have been applied to classify patients for predicting clinical outcomes and prognosis. However, further evidence is needed regarding the influence of molecular subtypes on the efficacy of radiotherapy (RT) after breast-conserving surgery (BCS), particularly in a population-based context. Hence, the present study employed a propensity-score-matched cohort design to investigate the potential role of molecular subtypes in stratifying patient outcomes for post-BCS RT and to identify the specific clinical benefits that may emerge.

METHODS

From 2006 to 2019, the present study included 59,502 breast cancer patients who underwent BCS from the Taiwan National Health Insurance Research Database. Propensity scores were utilized to match confounding variables between patients with and without RT within each subtype of breast cancer, namely luminal A, luminal B/HER2-negative, luminal B/HER2-positive, basal-like, and HER2-enriched ones. Several clinical outcomes were assessed, in terms of local recurrence (LR), regional recurrence (RR), distant metastasis (DM), disease-free survival (DFS), and overall survival (OS).

RESULTS

After post-BCS RT, patients with luminal A and luminal B/HER2-positive breast cancers exhibited a decrease in LR (adjusted hazard ratio [aHR] = 0.18, p < 0.0001; and, 0.24, p = 0.0049, respectively). Furthermore, reduced RR and improved DFS were observed in patients with luminal A (aHR = 0.15, p = 0.0004; and 0.29, p < 0.0001), luminal B/HER2-negative (aHR = 0.06, p = 0.0093; and, 0.46, p = 0.028), and luminal B/HER2-positive (aHR = 0.14, p = 0.01; and, 0.38, p < 0.0001) breast cancers. Notably, OS benefits were found in patients with luminal A (aHR = 0.62, p = 0.002), luminal B/HER2-negative (aHR = 0.30, p < 0.0001), basal-like (aHR = 0.40, p < 0.0001), and HER2-enriched (aHR = 0.50, p = 0.03), but not luminal B/HER2-positive diseases. Remarkably, when considering DM, luminal A patients who received RT demonstrated a lower cumulative incidence of DM than those without RT (p = 0.02).

CONCLUSION

In patients with luminal A breast cancer who undergo BCS, RT could decrease the likelihood of tumor metastasis. After RT, the tumor's hormone receptor status may predict tumor control regarding LR, RR, and DFS. Besides, the HER2 status of luminal breast cancer patients may serve as an additional predictor of OS after post-BCS RT. However, further prospective studies are required to validate these findings.

A systems biology approach and in vitro experiment indicated Rapamycin targets key cancer and cell cycle-related genes and miRNAs in triple-negative breast cancer cells

An anticancer drug known as Rapamycin acts by inhibiting the mammalian target of the Rapamycin pathway. This agent has recently been investigated for its potential therapeutic benefits in sensitizing drug-resistant breast cancer (BC) treatment. The molecular mechanism underlying these effects, however, is still a mystery. Using a systems biology method and in vitro experiment, this study sought to discover essential genes and microRNAs (miRNAs) targeted by Rapamycin in triple-negative BC (TNBC) cells to aid prospective new medications with less adverse effects in BC treatment. We developed the transcription factor-miRNA-gene and protein-protein interaction networks using the freely accessible microarray data sets. FANMOD and MCODE were utilized to identify critical regulatory motifs, clusters, and seeds. Then, functional enrichment analyses were conducted. Using topological analysis and motif detection, the most important genes and miRNAs were discovered. We used quantitative real-time polymerase chain reaction (qRT-PCR) to examine the effect of Rapamycin on the expression of the selected genes and miRNAs to verify our findings. We performed flow cytometry to investigate Rapamycin's impact on cell cycle and apoptosis. Furthermore, wound healing and migration assays were done. Three downregulated (PTGS2, EGFR, VEGFA) and three upregulated (c-MYC, MAPK1, PIK3R1) genes were chosen as candidates for additional experimental verification. There were also three upregulated miRNAs (miR-92a, miR-16, miR-20a) and three downregulated miRNAs (miR-146a, miR-145, miR-27a) among the six selected miRNAs. The qRT-PCR findings in MDA-MB-231 cells indicated that c-MYC, MAPK1, PIK3R1, miR-92a, miR-16, and miR-20a expression levels were considerably elevated following Rapamycin treatment, whereas PTGS2, EGFR, VEGFA, miR-146a, and miR-145 expression levels were dramatically lowered (p < 0.05). These genes are engaged in cancer pathways, transcriptional dysregulation in cancer, and cell cycle, according to the top pathway enrichment findings. Migration and wound healing abilities of the cells declined after Rapamycin treatment, and the number of apoptotic cells increased. We demonstrated that Rapamycin suppresses cell migration and metastasis in the TNBC cell line. In addition, our data indicated that Rapamycin induces apoptosis in this cell line. The discovered vital genes and miRNAs affected by Rapamycin are anticipated to have crucial roles in the pathogenesis of TNBC and its therapeutic resistance.

SUV39H1 Expression as a Guideline for Omitting Radiotherapy in Lymph Node-positive Triple-negative Breast Cancer Patients

BACKGROUND/AIM

The role of postoperative radiotherapy (RT) combined with chemotherapy (CT) for lymph node-positive (LN+) triple-negative breast cancer (TNBC) remains controversial. SUV39H1-mediated epigenetic regulation is associated with cancer cell migration, invasion, metastasis, and treatment resistance. This study aims to identify the role of SUV39H1 in TNBCs.

MATERIALS AND METHODS

Overall, 498 TNBCs with SUV39H1 RNA-seq profiles were retrieved from TCGA-BRCA and analyzed; the X-tile algorithm was used to stratify the population into low, intermediate, and high SUV39H1. Furthermore, we performed an in vitro clonogenic cell survival assay using the MDA-MB-231 cell line to assess the effects of SUV39H1 on cellular responses.

RESULTS

The results showed that SUV39H1 was significantly higher in TNBC than normal tissue and luminal subtype breast cancer. Notably, SUV39H1 is significantly expressed in the basal-like 1 (BL1) and immunomodulatory (IM) subgroups, compared to other subtypes. Compared to patients with a low or medium expression of SUV39H1, omitting RT only worsens disease-free survival (DFS) in those with high SUV39H1 expression. The experimental results showed SUV39H1 was suppressed by si-SUV39H1, and SUV39H1 knockdown in MDA-MB-231-IV2-1 cells enhanced the cellular toxicity of doxorubicin and paclitaxel.

CONCLUSION

Targeting SUV39H1 may provide a potential guiding indication of omitting RT to avoid over-treatment and chemosensitivity for TNBC.

Discovery of differentially expressed novel miRNAs in breast normal cells and their putative targets

MicroRNAs (miRNAs) play critical role in normal breast development and their altered expression may lead to breast cancer. Identification of new miRNAs allows us to understand the normal physiological process and associated disease pathophysiology. In the present study we identify the novel miRNAs in withaferin A treated breast normal cells (MCF-10A) using small RNA sequencing. The pathophysiological potential of the identified miRNAs was checked by studying their expression pattern in MDA-MB-231 and MCF-7 breast cancer cells using qRT-PCR technique. The secondary/tertiary structure of the identified miRNAs, target gene enrichment in Gene Ontology terms and KEGG pathway, miRNA-mRNA interaction of the sorted target genes, miRNA-mRNA/miRNA-argonaute protein/miRNA-mRNA-argonaute protein interaction and stability, were studied using bioinformatics tools/software, and molecular dynamics simulations. Hsa-miR-N88585 and hsa-miR-N461089 were identified and validated as novel miRNAs in normal breast cells. Up-expression of identified miRNAs in MDA-MB-231 and MCF-7 cells indicates their oncogenic nature. Identified target genes were enriched in classical signaling pathways (AMPK and Ras) and important GO terms. PLXDC2, BHLHE40, ARMC8, and PECAM1, CDC27, KCNK3 genes were sorted as putative targets for hsa-miR-N88585 and hsa-miR-N461089, respectively. MD simulation revealed stable hsa-miR-N88585/hsa-miR-N461089-AGO protein complex formation which indicates their further processing. In conclusion, the study identifies hsa-miR-N88585 and hsa-miR-N461089 as novel miRNAs in breast normal cells which are significantly inversely expressed in breast cancer cells. Further experiments are required to study the role of identified novel miRNAs in normal breast development and pathophysiology of breast cancer.

Functional impact of non-coding RNAs in high-grade breast carcinoma: Moving from resistance to clinical applications: A comprehensive review

Despite the recent advances in cancer therapy, triple-negative breast cancers (TNBCs) are the most relapsing cancer sub-type. It is partly due to their propensity to develop resistance against the available therapies. An intricate network of regulatory molecules in cellular mechanisms leads to the development of resistance in tumors. Non-coding RNAs (ncRNAs) have gained widespread attention as critical regulators of cancer hallmarks. Existing research suggests that aberrant expression of ncRNAs modulates the oncogenic or tumor suppressive signaling. This can mitigate the responsiveness of efficacious anti-tumor interventions. This review presents a systematic overview of biogenesis and down streaming molecular mechanism of the subgroups of ncRNAs. Furthermore, it explains ncRNA-based strategies and challenges to target the chemo-, radio-, and immunoresistance in TNBCs from a clinical standpoint.

The Role of miRNAs in the Prognosis of Triple-Negative Breast Cancer: A Systematic Review and Meta-Analysis

Breast cancer is one of the most common malignancies among women around the world. The basal or triple-negative subtype (TNBC) is a heterogeneous group of tumors, characterized by its aggressive and metastatic nature, with low survival and worse prognosis. Research on genetic biomarkers, such as microRNAs (miRs) in TNBC, demonstrate their relevance in the prognosis of the disease. Therefore, the objective of this research was to verify the role of miRs in the prognosis of TNBC. A search was carried out in the PubMed (MEDLINE), Web of Science, and Scopus databases, with articles in the English language from 2010 to 2022. Only articles that analyzed the role of miRNAs in the prognosis of TNBC and that met the criteria of the MOOSE method were included. For the preparation and planning of this systematic review, a PRISMA checklist and the MOOSE method were used. The Newcastle-Ottawa Scale was used to analyze the quality of the included studies. The excluded criteria considered were: (1) studies that presented duplication in the databases; (2) reviews of the literature, clinical case reports, meta-analyses, conference abstracts, letters to the editor, theses, dissertations, and book chapters; (3) studies that stratified only women diagnosed with other subtypes of breast cancer subtypes; (4) experiments without a control or comparison group. After the bibliographic survey of the 2.274 articles found, 43 articles met the inclusion criteria, totaling 5421 patients with TNBC analyzed for this review. Six miRs (miR-155, miR-21, miR-27a/b/, miR-374a/b, miR-30a/c/e, and miR-301a) were included in the meta-analysis. A low expression of miR-155 was associated with reduced overall survival (OS) (HR: 0.68, 95% CI: 0.58-0.81). A high expression of miR-21 was a predictor of OS reduction (HR: 2.56; 95% CI: 1.49-4.40). In addition, high levels of miR-27a/b and miR-301a/b were associated with lower OS, while the decreased expression levels of miR-30 and miR-374a/b were associated with worse relapse-free survival (RFS) and shorter disease-free survival (DFS), respectively. The present study revealed that miRs play essential roles in the development of metastases, in addition to acting as suppressors of the disease, thus improving the prognosis of TNBC. However, the clinical application of these findings has not yet been investigated.

The metabolic addiction of cancer stem cells

Cancer stem cells (CSC) are the minor population of cancer originating cells that have the capacity of self-renewal, differentiation, and tumorigenicity (when transplanted into an immunocompromised animal). These low-copy number cell populations are believed to be resistant to conventional chemo and radiotherapy. It was reported that metabolic adaptation of these elusive cell populations is to a large extent responsible for their survival and distant metastasis. Warburg effect is a hallmark of most cancer in which the cancer cells prefer to metabolize glucose anaerobically, even under normoxic conditions. Warburg's aerobic glycolysis produces ATP efficiently promoting cell proliferation by reprogramming metabolism to increase glucose uptake and stimulating lactate production. This metabolic adaptation also seems to contribute to chemoresistance and immune evasion, a prerequisite for cancer cell survival and proliferation. Though we know a lot about metabolic fine-tuning in cancer, what is still in shadow is the identity of upstream regulators that orchestrates this process. Epigenetic modification of key metabolic enzymes seems to play a decisive role in this. By altering the metabolic flux, cancer cells polarize the biochemical reactions to selectively generate "onco-metabolites" that provide an added advantage for cell proliferation and survival. In this review, we explored the metabolic-epigenetic circuity in relation to cancer growth and proliferation and establish the fact how cancer cells may be addicted to specific metabolic pathways to meet their needs. Interestingly, even the immune system is re-calibrated to adapt to this altered scenario. Knowing the details is crucial for selective targeting of cancer stem cells by choking the rate-limiting stems and crucial branch points, preventing the formation of onco-metabolites.

Prognostic and clinical significance of subcellular CDC27 for patients with rectal adenocarcinoma treated with adjuvant chemotherapy

Rectal adenocarcinoma (READ) constitutes one-third of newly diagnosed colorectal cancer cases. Surgery, chemotherapy and concurrent chemoradiotherapy are the main treatments to improve patient outcomes for READ. However, patients with READ receiving these treatments eventually relapse, leading to a poor survival outcome. The present study collected surgical specimens from patients with READ and determined that cytoplasmic cell division cycle 27 (CDC27) expression was associated with the risk of lymph node metastasis and distant metastasis. Nuclear CDC27 expression was negatively associated with 5-year disease-free survival (DFS) and 5-year overall survival (OS) rates. Multivariate Cox proportional regression analysis showed that nuclear CDC27 was an independent prognostic factor in the patients with READ, especially in those treated with adjuvant chemotherapy. High nuclear CDC27 expression was significantly associated with poorer 5-year DFS (HR, 2.106; 95% CI, 1.275-3.570; P=0.003) and 5-year OS (HR, 2.369; 95% CI, 1.270-4.6810; P=0.005) rates. The data indicated that cytoplasmic CDC27 expression could affect tumor progression and that it plays an important role in metastasis. Nuclear CDC27 expression was markedly associated with poorer survival outcomes and was an independent prognostic factor in patients with postoperative adjuvant chemotherapy-treated READ. Thus, CDC27 expression serves as a potential prognostic marker for rectal tumor progression and chemotherapy treatment.

Effects of noncoding RNAs in radiotherapy response in breast cancer: a systematic review

Radiotherapy has an essential role in breast cancer treatment. However, tumor cells may be resistant to radiotherapy. Noncoding RNAs are considered regulators of different pathways which modulate radiotherapy. This systematic review classifies long noncoding RNAs, and microRNAs precipitated in the radiation response of breast cancer patients. A total of 14 microRNAs and 8 long noncoding RNAs were studied in this review. MiR-22, miR-200 c, Let7, and LINP1 as tumor suppressors increase the effect of radiotherapy in BC. However, some noncoding RNAs such as HOTAIR, NEAT1, and miR-21 are precipitated in radio-resistance breast cancers. Significant changes in the pattern of noncoding RNAs expression before and after radiotherapy make them a good candidate for the prognosis and prediction of radiotherapy response. MiR-21 and miR-182 can promote radio-resistance via cancer stem cells. At last, the molecular mechanisms initiating radio-resistance were also examined to find the candidate noncoding RNAs for the development of radiation-sensitized agents.

Radiation therapy for triple-negative breast cancer: emerging role of microRNAs as biomarkers and radiosensitivity modifiers. A systematic review

PURPOSE

Radiation therapy (RT) for triple-negative breast cancer (TNBC) treatment is currently delivered in the adjuvant setting and is under investigation as a booster of neoadjuvant treatments. However, TNBC radioresistance remains an obstacle, so new biomarkers are needed to select patients for any integration of RT in the TNBC therapy sequence. MicroRNAs (miRs) are important regulators of gene expression, involved in cancer response to ionizing radiation (IR) and assessable by tumor tissue or liquid biopsy. This systematic review aimed to evaluate the relationships between miRs and response to radiation in TNBC, as well as their potential predictive and prognostic values.

METHODS

A thorough review of studies related to miRs and RT in TNBC was performed on PubMed, EMBASE, and Web of Science. We searched for original English articles that involved dysregulation of miRs in response to IR on TNBC-related preclinical and clinical studies. After a rigorous selection, 44 studies were chosen for further analysis.

RESULTS

Thirty-five miRs were identified to be TNBC related, out of which 21 were downregulated, 13 upregulated, and 2 had a double-side expression in this cancer. Expression modulation of many of these miRs is radiosensitizing, among which miR-7, -27a, -34a, -122, and let-7 are most studied, still only in experimental models. The miRs reported as most influencing/reflecting TNBC response to IR are miR-7, -27a, -155, -205, -211, and -221, whereas miR-21, -33a, -139-5p, and -210 are associated with TNBC patient outcome after RT.

CONCLUSION

miRs are emerging biomarkers and radiosensitizers in TNBC, worth further investigation. Dynamic assessment of circulating miRs could improve monitoring and TNBC RT efficacy, which are of particular interest in the neoadjuvant and the high-risk patients' settings.

Role of non-coding RNAs in response of breast cancer to radiation therapy

Breast cancer ranks as the first common cancer with a high incidence rate and mortality among women. Radiation therapy is the main therapeutic method for breast cancer patients. However, radiation resistance of tumor cells can reduce the efficacy of treatment and lead to recurrence and mortality in patients. Non-coding RNA (ncRNAs) refers to a group of small RNA molecules that are not translated into protein, while they have the ability to modulate the translation of target mRNA. Several studies have reported the altered expression of ncRNAs in response to radiation in breast cancer. NcRNAs have been found to influence on radiation response of breast cancer by regulating various mechanisms, including DNA damage response, cell cycle regulation, cell death, inflammatory response, cancer stem cell and EGFR related pathways. This paper aimed to provide a summary of current findings on ncRNAs dysregulation after irradiation. We also present the function and mechanism of ncRNAs in modulating radiosensitivity or radioresistance of breast cancer cells.

Whole-Exome Sequencing of HPV Positive Tonsillar and Base of Tongue Squamous Cell Carcinomas Reveals a Global Mutational Pattern along with Relapse-Specific Somatic Variants

Simple Summary

To better prevent/combat recurrence and identify predictive/targetable markers upon diagnosis, we performed whole-exome sequencing (WES) of primary tumours and relapses of human papillomavirus positive (HPV⁺) tonsillar and base of tongue cancer (TSCC/BOTSCC) on patients treated with curative intent, with and without relapse. A specific deletion in the CDC27 gene was observed only in the primaries of 5/17 patients that recurred but in none of the 18 patients without recurrence. Furthermore, three specific variants and 26 mutated genes enriched in mucins were identified in at least 30% of all primaries irrespective of recurrence. To conclude, a specific CDC27 deletion could be specific for recurrent HPV⁺ TSCC/BOTSCC, while BCLAF1, AQP7 and other globally mutated genes could be of significance for further investigation.

Abstract

To identify predictive/targetable markers in human papillomavirus positive (HPV⁺) tonsillar and base of tongue cancer (TSCC/BOTSCC), whole-exome sequencing (WES) of tumours of patients with/without recurrence was performed. Forty primary tumours and adjacent normal tissue were separated by micro-dissection from formalin-fixed paraffin-embedded tissue from patients treated with curative intent 2000–2014 at Karolinska University Hospital. Successful sequencing was obtained in primary tumours of 18 patients without and primaries of 17 with local or distant recurrence, as well as in 10 corresponding recurrences (i.e., five local relapses and five distant metastases) from these 17 patients. One variant—a high-impact deletion in the CDC27 gene—was observed only in primaries of 5/17 patients that had a recurrence after full treatment but in none of those without recurrence. In addition, 3 variants and 26 mutated genes, including CDC27, BCLAF1 and AQP7, were present in at least 30% of all primary tumours independent of prognosis. To conclude, a CDC27 deletion was specific and found in ~30% of samples from patients with a local relapse/distant metastasis and could, therefore, potentially be a prospective marker to predict prognosis. Commonly mutated genes, such as BCLAF1, should be further studied in the context of targeted therapy.

Non-Coding RNAs Associated With Radioresistance in Triple-Negative Breast Cancer

The resistance that Triple-Negative Breast Cancer (TNBC), the most aggressive breast cancer subtype, develops against radiotherapy is a complex phenomenon involving several regulators of cell metabolism and gene expression; understanding it is the only way to overcome it. We focused this review on the contribution of the two leading classes of regulatory non-coding RNAs, microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), against ionizing radiation-based therapies. We found that these regulatory RNAs are mainly associated with DNA damage response, cell death, and cell cycle regulation, although they regulate other processes like cell signaling and metabolism. Several regulatory RNAs regulate multiple pathways simultaneously, such as miR-139-5p, the miR-15 family, and the lncRNA HOTAIR. On the other hand, proteins such as CHK1 and WEE1 are targeted by several regulatory RNAs simultaneously. Interestingly, the study of miRNA/lncRNA/mRNA regulation axes increases, opening new avenues for understanding radioresistance. Many of the miRNAs and lncRNAs that we reviewed here can be used as molecular markers or targeted by upcoming therapeutic options, undoubtedly contributing to a better prognosis for TNBC patients.

HPV16 E6 enhances the radiosensitivity in HPV-positive human head and neck squamous cell carcinoma by regulating the miR-27a-3p/SMG1 axis

Background

Head and neck squamous cell carcinoma (HNSCC) is the 6th most common malignant cancer type worldwide. Radiosensitivity has been shown to be significantly increased in patients with human papillomavirus (HPV)-positive HNSCC compared with HPV-negative patients. However, the clinical significance of HPV and its regulatory mechanisms in HNSCC are largely unknown. The aim of our study was to explore the regulatory mechanism of miR-27a-3p in the radiosensitivity of HPV-positive HNSCC cells.

Methods

E6-overexpressing and E6-knockdown HNSCC cell lines were generated and the transfection efficiencies were evaluated by quantitative real-time PCR (RT-qPCR) and western blotting. The expression of miR-27a-3p and DiGeorge syndrome critical region 8 (DGCR8) was examined by RT-qPCR after transfection with E6 overexpressing plasmid or E6 siRNA. The effects of miR-27a-3p on the radiosensitivity of HNSCC cells were explored by a colony formation and TUNEL staining assays. Bioinformatic tools and luciferase reporter assays were used to identify that SMG1 is the direct target of miR-27a-3p. Furthermore, the effect of E6 overexpression on the regulation of the miR-27a-3p/SMG1 axis was investigated.

Results

In our study, we found overexpression of HPV E6 upregulated the expression of DGCR8 and miR-27a-3p in HNSCC cells. We next confirmed that DGCR8 positively regulated the expression of miR-27a-3p in HNSCC cells. The luciferase reporter gene results verified that miR-27a-3p targeted the 3’UTR of SMG1 mRNA. MiR-27a-3p mimics transfection resulted in a decrease in SMG1 expression and miR-27a-3p inhibitor transfection increased SMG1 expression. Apoptotic activity of HNSCC cells was significantly increased in miR-27a-3p mimics HNSCC cells compared with control HNSCC cells. After treatment with 4 Gy irradiation, UM-SCC47 cells transfected with miR-27a-3p inhibitor or SMG1 overexpressing plasmid formed more colonies than the corresponding control cells. Furthermore, the rescue experiments demonstrated that HPV16 E6 improved the radiosensitivity of HNSCC cells by targeting miR-27a-3p/SMG1.

Conclusion

Our study demonstrated that HPV16 E6 activated the DGCR8/miR-27a-3p/SMG1 axis to enhance the radiosensitivity. Our findings might provide a novel therapeutic target to improve the response of HNSCC to radiotherapy.

Circular RNA hsa_circ_0044234 as distinct molecular signature of triple negative breast cancer: a potential regulator of GATA3

BACKGROUND

Circular RNAs (circRNAs) have been implicated in the initiation and development of breast cancer as functional non-coding RNAs (ncRNA). The roles of circRNAs as the competing endogenous RNAs (ceRNAs) to sponge microRNAs (miRNAs) have also been indicated. However, the functions of circRNAs in breast cancer have not been totally elucidated. This study aimed to explore the clinical implications and possible roles of circ_0044234 in carcinogenesis of the most problematic BC subtype, triple negative breast cancer (TNBC), which are in desperate need of biomarkers and targeted therapies.

METHODS

The importance of circ_0044234 as one of the most dysregulated circRNAs in TNBC was discovered through microarray expression profile analysis. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to confirm the downregulation of circ_0044234 in triple negative tumors and cell lines versus non-triple negative ones. The bioinformatics prediction revealed that circ_0044234 could act as an upstream sponge in the miR-135b/GATA3 axis, two of the most dysregulated transcripts in TNBC.

RESULTS

Our experimental investigation of circ_0044234 expressions in various BC subtypes as well as cell lines reveals that TNBC expresses circ_0044234 at a substantially lower level than non-TNBC. The ROC curve analysis indicates that it could be applied as a discriminative biomarker to identify TNBC from other BC subtypes. Moreover, circ_0044234 expression could be an independent prognostic biomarker in BC. Interestingly, a substantial inverse expression correlation was detected between circ_0044234 and miR-135b-5p as well as between miR-135b-5p and GATA3 in breast tumors.

CONCLUSIONS

The possible clinical usefulness of circ_0044234 as a promising distinct biomarker and upcoming therapeutic target for TNBC have been indicated in this research. Our comprehensive approach revealed the potential circ_0044234/miR135b-5p/GATA3 ceRNA axis in TNBC.

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

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

HOXD Antisense Growth-Associated Long Noncoding RNA Promotes Triple-Negative Breast Cancer Progression by Activating Wnt Signaling Pathway

PURPOSE

Triple-negative breast cancer (TNBC) is the most lethal subtype of breast cancer owing to high heterogeneity, aggressive nature, and lack of treatment options, which has a substantial deleterious effect on patients' lives. HOXD antisense growth-associated long noncoding RNA (lncRNA) (HAGLR) plays tumor-promoting roles in many cancers. In this study, we aimed to explore the role of HAGLR in TNBC.

METHODS

Quantitative real-time polymerase chain reaction assays were used to examine the expression of RNAs. Functional experiments were conducted to test the biological behavior of TNBC cells. Moreover, MS2-RNA immunoprecipitation, luciferase reporter, and RNA pull-down assays were conducted to verify the binding relationship between HAGLR, microRNA-143-5p (miR-143-5p), and serine- and arginine-rich splicing factor 1 (SRSF1).

RESULTS

HAGLR was found to be highly expressed in TNBC tissues and cells, and inhibiting HAGLR suppressed cell proliferation, migration, and invasion and promoted cell apoptosis in TNBC. Meanwhile, miR-93-5p was shown to bind to HAGLR and SRSF1. In addition, SRSF1 plays an oncogenic role in TNBC. Importantly, HAGLR could activate the Wnt signaling pathway by sponging miR-93-5p to upregulate SRSF1; thus, accelerating TNBC progression.

CONCLUSION

HAGLR could promote the progression of TNBC through the miR-93-5p/SRSF1 axis to activate the Wnt signaling pathway.

The Anticancer Effects of Flavonoids through miRNAs Modulations in Triple-Negative Breast Cancer

Triple- negative breast cancer (TNBC) incidence rate has regularly risen over the last decades and is expected to increase in the future. Finding novel treatment options with minimum or no toxicity is of great importance in treating or preventing TNBC. Flavonoids are new attractive molecules that might fulfill this promising therapeutic option. Flavonoids have shown many biological activities, including antioxidant, anti-inflammatory, and anticancer effects. In addition to their anticancer effects by arresting the cell cycle, inducing apoptosis, and suppressing cancer cell proliferation, flavonoids can modulate non-coding microRNAs (miRNAs) function. Several preclinical and epidemiological studies indicate the possible therapeutic potential of these compounds. Flavonoids display a unique ability to change miRNAs' levels via different mechanisms, either by suppressing oncogenic miRNAs or activating oncosuppressor miRNAs or affecting transcriptional, epigenetic miRNA processing in TNBC. Flavonoids are not only involved in the regulation of miRNA-mediated cancer initiation, growth, proliferation, differentiation, invasion, metastasis, and epithelial-to-mesenchymal transition (EMT), but also control miRNAs-mediated biological processes that significantly impact TNBC, such as cell cycle, immune system, mitochondrial dysregulation, modulating signaling pathways, inflammation, and angiogenesis. In this review, we highlighted the role of miRNAs in TNBC cancer progression and the effect of flavonoids on miRNA regulation, emphasizing their anticipated role in the prevention and treatment of TNBC.

The importance of CDC27 in cancer: molecular pathology and clinical aspects

Background

CDC27 is one of the core components of Anaphase Promoting complex/cyclosome. The main role of this protein is defined at cellular division to control cell cycle transitions. Here we review the molecular aspects that may affect CDC27 regulation from cell cycle and mitosis to cancer pathogenesis and prognosis.

Main text

It has been suggested that CDC27 may play either like a tumor suppressor gene or oncogene in different neoplasms. Divergent variations in CDC27 DNA sequence and alterations in transcription of CDC27 have been detected in different solid tumors and hematological malignancies. Elevated CDC27 expression level may increase cell proliferation, invasiveness and metastasis in some malignancies. It has been proposed that CDC27 upregulation may increase stemness in cancer stem cells. On the other hand, downregulation of CDC27 may increase the cancer cell survival, decrease radiosensitivity and increase chemoresistancy. In addition, CDC27 downregulation may stimulate efferocytosis and improve tumor microenvironment.

Conclusion

CDC27 dysregulation, either increased or decreased activity, may aggravate neoplasms. CDC27 may be suggested as a prognostic biomarker in different malignancies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-01860-9.

Progress of non-coding RNAs in triple-negative breast cancer

Non-coding RNAs (ncRNAs) include miRNA, lncRNA, and circRNA. NcRNAs are involved in multiple biological processes, including chromatin remodeling, signal transduction, post-transcriptional modification, cell autophagy, carbohydrate metabolism, and cell cycle regulation. Triple negative breast cancer (TNBC) is notorious for high invasiveness and metastasis, poor prognosis, and high mortality, and it is the most malignant breast cancer, while the effective targets for TNBC treatment are still lacking. NcRNAs act as oncogenes or suppressor genes, as well as promote or inhibit the occurrence and development of TNBC. Here, we reviewed some important miRNAs, lncRNAs, circRNAs, their target(s) and molecular mechanisms in TNBC. It is benefited to understand the occurrence and development of TNBC, further some ncRNAs might be potential targets for TNBC treatment.

Role of miRNAs in regulating responses to radiotherapy in human breast cancer

Breast cancer is the most common type of cancer that affects females globally. Radiotherapy is a standard treatment option for breast cancer, where one of its most significant limitations is radioresistance development. MicroRNAs (miRNAs) are small, non-protein-coding RNAs that have been widely studied for their roles as disease biomarkers. To date, several in vitro, in vivo, and clinical studies have reported the roles of miRNAs in regulating radiosensitivity and radioresistance in breast cancer cells. This article reviews the roles of miRNAs in regulating treatment response toward radiotherapy and the associating cellular pathways. We identified 36 miRNAs that play a role in mediating radio-responses; 22 were radiosensitizing, 12 were radioresistance-promoting, and two miRNAs were reported to promote both effects. A brief overview of breast cancer therapy options, mechanism of action of radiation, and molecular mechanism of radioresistance was provided in this article. A summary of the latest clinical researches involving miRNAs in breast cancer radiotherapy was also included.

MiR-27a Facilitates Breast Cancer Progression via GSK-3β

Breast cancer remains one of the leading causes of cancer-associated death in women. MiR-27a is highly expressed in breast cancer tissue. However, the underlying mechanisms that promote breast cancer progression are unknown. In this study, we investigated the regulatory mechanisms of miR-27a and its target glycogen Synthase Kinase 3-β (GSK-3β) in breast cancer cells. We found that miR-27a was highly expressed in breast cancer tissues, which downregulated GSK-3β expression. We further identified GSK-3β as a direct target of miR-27a, and found that the miR-27a mediated suppression of GSK-3β activated Wnt/β-catenin-associated proliferative and invasive factor in breast cancer. The cell transfection assay demonstrated the overexpression of miR-27a also enhanced cell proliferation and invasion, and reduced cell apoptosis through GSK-3β. Finally, we demonstrated that the overexpression of miR-27a facilitated breast cancer progression through its ability to down-regulate the phosphorylation of GSK-3β both in vivo and vitro. These findings highlighted miR-27a as a novel therapeutic target in breast cancer.

MicroRNA-27a-3p Reverses Adriamycin Resistance by Targeting BTG2 and Activating PI3K/Akt Pathway in Breast Cancer Cells

Aim

This study aimed to explore the regulative mechanisms of miR-27a-3p in chemo-resistance of breast cancer cells.

Materials and Methods

qRT-PCR was employed to determine miR-27a-3p expression in two breast cancer cell lines, MCF-7 and MCF-7/adriamycin-resistant cell line (MCF-7/ADR). The two cell lines were treated with miR-27a-3p mimics or inhibitors or corresponding negative control (NC), respectively. The changes were investigated by qRT-PCR, CCK-8 assay, Western blot (WB), colony formation assay, and flow cytometry assay. Moreover, luciferase reporter assay was analyzed to verify the downstream target gene of miR-27a-3p. Further investigation in the correlation between miR-27a-3p and BTG2 was launched by WB, flow cytometry assay, and CCK-8 assay. The expression of Akt and p-Akt was detected by WB.

Key Findings

Significantly higher miR-27a-3p expression was confirmed in MCF-7/ADR as compared with sensitive cell line MCF-7 (P<0.05). The down-regulation of miR-27a-3p in MCF-7/ADR enhanced the sensitivity of cancer cells to adriamycin treatment, decreased multidrug resistance gene 1/P-glycoprotein (MDR1/P-gp) expression, enhanced the apoptosis-related proteins expression, increased adriamycin-induced apoptosis, and inhibited cell proliferation as compared to NC groups (P<0.05). The up-regulation of miR-27a-3p in MCF-7 showed the opposite results. BTG2 is identified as a direct target of miR-27a-3p and its down-regulation reversed ADR-resistance. BTG2 treatment exhibited inhibitory effect on PI3K/Akt pathway in MCF-7/ADR cells.

Significance

miR-27a-3p might be associated with resistance of breast cancer cells to adriamycin treatments, modulating cell proliferation and apoptosis by targeting BTG2 and promoting the PI3K/Akt pathway in breast cancer cells. miR-27a-3p/BTG2 axis might be a potential therapeutic target for clinical BC resistance.

Small Non-Coding RNA Profiling Identifies miR-181a-5p as a Mediator of Estrogen Receptor Beta-Induced Inhibition of Cholesterol Biosynthesis in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a highly heterogeneous disease, representing the most aggressive breast cancer (BC) subtype with limited treatment options due to a lack of estrogen receptor alpha (ERα), progesterone receptor (PR), and Erb-B2 receptor tyrosine kinase 2 (HER2/neu) expression. Estrogen receptor beta (ERβ) is present in a fraction of TNBC patients, where its expression correlates with improved patient outcomes, supported by the fact that it exerts oncosuppressive effects in TNBC cell models in vitro. ERβ is involved in microRNA-mediated regulation of gene expression in hormone-responsive BC cells and could mediate its actions through small noncoding RNAs (sncRNAs) in TNBCs also. To verify this possibility, smallRNA sequencing was performed on three ERβ-expressing cell lines from different TNBC molecular subtypes. Several sncRNAs resulted modulated by ERβ, with a subset being regulated in a tumor subtype-independent manner. Interestingly, sncRNA profiling of 12 ERβ+and 32 ERβ− primary TNBC biopsies identified 7 microRNAs, 1 PIWI-interacting RNA (piRNA), and 1 transfer RNA (tRNA) differentially expressed in ERβ+ compared to ERβ− tumors and cell lines. Among them, miR-181a-5p was found to be overexpressed in ERβ+ tumors and predicted target key components of the cholesterol biosynthesis pathway previously found to be inhibited by ERβ in TNBC cells.

MicroRNA-based potential diagnostic, prognostic and therapeutic applications in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a distinct subtype of breast cancer characterized by high recurrence rates and poor prognosis compared to other breast cancers. MicroRNAs (miRNAs) are small non-coding RNAs that regulate the expression of various post-transcriptional gene and silence a broad set of target genes. Many recent studies have demonstrated that miRNAs play an important role in the initiation, promotion, malignant conversion, progression, and metastasis of TNBC. Therefore, the aim of this review is to focus on recent advancements of microRNAs-based potential applications in diagnosis, treatment and prognosis of triple-negative breast cancer.

MicroRNAs Involved in Carcinogenesis, Prognosis, Therapeutic Resistance and Applications in Human Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive, prevalent, and distinct subtype of breast cancer characterized by high recurrence rates and poor clinical prognosis, devoid of both predictive markers and potential therapeutic targets. MicroRNAs (miRNA/miR) are a family of small, endogenous, non-coding, single-stranded regulatory RNAs that bind to the 3′-untranslated region (3′-UTR) complementary sequences and downregulate the translation of target mRNAs as post-transcriptional regulators. Dysregulation miRNAs are involved in broad spectrum cellular processes of TNBC, exerting their function as oncogenes or tumor suppressors depending on their cellular target involved in tumor initiation, promotion, malignant conversion, and metastasis. In this review, we emphasize on masses of miRNAs that act as oncogenes or tumor suppressors involved in epithelial–mesenchymal transition (EMT), maintenance of stemness, tumor invasion and metastasis, cell proliferation, and apoptosis. We also discuss miRNAs as the targets or as the regulators of dysregulation epigenetic modulation in the carcinogenesis process of TNBC. Furthermore, we show that miRNAs used as potential classification, prognostic, chemotherapy and radiotherapy resistance markers in TNBC. Finally, we present the perspective on miRNA therapeutics with mimics or antagonists, and focus on the challenges of miRNA therapy. This study offers an insight into the role of miRNA in pathology progression of TNBC.

Three-microRNA expression signature predicts survival in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a specific type of breast cancer with poor overall survival (OS) time. Previous studies revealed that microRNAs (miRNAs/miRs) serve important roles in the pathogenesis, progression and prognosis of TNBC. The present study analyzed the miRNA expression and clinical data of patients with TNBC downloaded from The Cancer Genome Atlas. A total of 194 differentially expressed miRNAs were identified between TNBC and matched normal tissues using the cut-off criteria of P<0.05 and |log2 fold change|>2. Of these miRNAs, 65 were downregulated and 129 were upregulated. Using Kaplan-Meier survival analysis, a total of 77 miRNAs that were closely associated with OS time were identified (P<0.05). The intersection of the 77 miRNAs and 194 differentially expressed miRNAs revealed six miRNAs. Log-rank tests based on survival curves were performed and two miRNAs were eliminated. The prognostic value of the remaining four miRNAs was evaluated with a Cox proportional hazards model using multiple logistic regression with forward stepwise selection of variables. Three miRNAs (miR-21-3p, miR-659-5p and miR-200b-5p) were subsequently identified as independent risk factors associated with OS time in the model. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses revealed that the target genes of these three miRNAs were mainly involved in ‘cell protein metabolism’, ‘RNA transcriptional regulation’, ‘cell migration’, ‘MAPK signaling pathway’, ‘ErbB signaling pathway’, ‘prolactin signaling pathway’ and ‘adherens junctions’. Taken together, the results obtained in the present study suggested that the three-miRNA signature may serve as a prognostic biomarker for patients with TNBC.

MicroRNA-27a (miR-27a) in Solid Tumors: A Review Based on Mechanisms and Clinical Observations

MicroRNAs (miRNAs) are a family of highly conserved, non-coding single-stranded RNAs transcribed as ~70 nucleotide precursors to an 18–22 nucleotide product (1). miRNAs can silence their homologous target genes at the post-transcriptional level, and these genes have been revealed to play an important role in tumorigenesis, invasion and metastasis (2). MicroRNA-27a (miR-27a), transcripted by miR-27a gene, has proved to implicate with many kinds of solid tumors, showing potential as a useful biomarker or drug target for clinical application. However, even though miR-27a has been reported in many cancers, the mechanism and signal pathways of miR-27 in oncogenesis, invasion, and metastasis are still obscure. Moreover, recent studies show that miR-27a pays an important role in epithelial-mesenchymal-transition, regulating tumor immune response, and chemoresistance. In this review, we summarize the current literature, demonstrate the established link between miR-27a and tumorigenesis, and focus on recently identified mechanisms. The review also aims to demonstrate the potential of miR-27a as a diagnostic and/or prognostic biomarker in solid tumors and to discuss the possibilities of targeted therapy and drug design.

Role of miRNA-Regulated Cancer Stem Cells in the Pathogenesis of Human Malignancies

Recent biomedical discoveries have revolutionized the concept and understanding of carcinogenesis, a complex and multistep phenomenon which involves accretion of genetic, epigenetic, biochemical, and histological changes, with special reference to MicroRNAs (miRNAs) and cancer stem cells (CSCs). miRNAs are small noncoding molecules known to regulate expression of more than 60% of the human genes, and their aberrant expression has been associated with the pathogenesis of human cancers and the regulation of stemness features of CSCs. CSCs are the small population of cells present in human malignancies well-known for cancer resistance, relapse, tumorigenesis, and poor clinical outcome which compels the development of novel and effective therapeutic protocols for better clinical outcome. Interestingly, the role of miRNAs in maintaining and regulating the functioning of CSCs through targeting various oncogenic signaling pathways, such as Notch, wingless (WNT)/β-Catenin, janus kinases/ signal transducer and activator of transcription (JAK/STAT), phosphatidylinositol 3-kinase/ protein kinase B (PI3/AKT), and nuclear factor kappa-light-chain-enhancer of activated B (NF-kB), is critical and poses a huge challenge to cancer treatment. Based on recent findings, here, we have documented the regulatory action or the underlying mechanisms of how miRNAs affect the signaling pathways attributed to stemness features of CSCs, such as self-renewal, differentiation, epithelial to mesenchymal transition (EMT), metastasis, resistance and recurrence etc., associated with the pathogenesis of various types of human malignancies including colorectal cancer, lung cancer, breast cancer, head and neck cancer, prostate cancer, liver cancer, etc. We also shed light on the fact that the targeted attenuation of deregulated functioning of miRNA related to stemness in human carcinogenesis could be a viable approach for cancer treatment.

miR‑27a promotes human breast cancer cell migration by inducing EMT in a FBXW7‑dependent manner

Increasingly, evidence has revealed that aberrant microRNA (miRNA) expression is involved in breast cancer carcinogenesis and further progression, including metastasis. miRNA (miR)‑27a was previously identified to be abnormally expressed and to serve pro‑oncogenic functions in multiple human cancer types, including breast cancer. However, its functions and underlying mechanisms in breast cancer remain poorly understood. In the present study, it was demonstrated that miR‑27a was significantly upregulated in breast cancer tissues and cell lines compared with their normal counterparts. Overexpression of miR‑27a resulted in enhanced cell migration by inducing epithelial‑to‑mesenchymal transition, while its knockdown effectively reversed these cellular events. The present study additionally confirmed for the first time, to the best of our knowledge, that F‑box and WD repeat domain containing 7 (FBXW7) is a downstream target gene of miR‑27a in human breast cancer cells. FBXW7 is underexpressed in breast cancer tissues and cell lines, and is an independent positive factor for the overall survival rate of patients with breast cancer. Notably, the ectopic expression of FBXW7 may effectively suppress the epithelial‑to‑mesenchymal transition and migratory activity of breast cancer cells, in addition to reversing the cell migration mediated by miR‑27a. Altogether, the results of the present study indicated the important function of miR‑27a in regulating the metastasis of breast cancer in a FBXW7‑dependent manner, and provide evidence for the potential application of miR‑27a in breast cancer therapy.

mir-218-2 promotes glioblastomas growth, invasion and drug resistance by targeting CDC27

Glioma has become a significant global health problem with substantial morbidity and mortality, underscoring the importance of elucidating its underlying molecular mechanisms. Recent studies have identified mir-218 as an anti-oncogene; however, the specific functions of mir-218-1 and mir-218-2 remain unknown, especially the latter. The objective of this study was to further investigate the role of mir-218-2 in glioma. Our results indicated that mir-218-2 is highly overexpressed in glioma. Furthermore, we showed that mir-218-2 is positively correlated with the growth, invasion, migration, and drug susceptibility (to β-lapachone) of glioma cells. In vitro, the overexpression of mir-218-2 promoted glioma cell proliferation, invasion, and migration. In addition, the overexpression of mir-218-2 in vivo was found to increase glioma tumor growth. Accordingly, the inhibition of mir-218-2 resulted in the opposite effects. Cell division cycle 27 (CDC27), the downstream target of mir-218-2, is involved in the regulation of glioma cells. Our results indicate that the overexpression of CDC27 counteracted the function of mir-218-2 in glioma cells. These novel findings provide new insight in the application of mir-218-2 as a potential glioma treatment.

MicroRNAs in the prognosis of triple-negative breast cancer: A systematic review and meta-analysis

BACKGROUND

Triple-negative breast cancer (TNBC) is a heterogeneous group of tumors characterized by their aggressive nature and poor associated survival. MicroRNAs (miRs) have been found to play an important role in the occurrence and development of human cancers, but their role in the prognosis of TNBC patients remains unclear. We performed a meta-analysis to explore the prognostic value of miRs in TNBC.

METHODS

We systematically searched the PubMed, Embase, and Web of Science databases to identify eligible studies. A meta-analysis was performed to estimate the pooled hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) for the associations between levels of miR expression (predictive factors) and overall survival (OS) and disease-free survival (DFS) (outcomes) in patients with TNBC.

RESULTS

After performing the literature search and review, 21 relevant studies including 2510 subjects were identified. Six miRs (miR-155, miR-21, miR-27a/b, miR-374a/b, miR-210, and miR-454) were assessed in the meta-analysis. Decreased expression of miR-155 was associated with reduced OS (adjusted HR = 0.58, 95% CI: 0.34-0.99; crude HR = 0.67, 95% CI: 0.58-0.79). High miR-21 expression was also predictive of reduced OS (crude HR = 2.50, 95% CI: 1.56-4.01). We found that elevated levels of miR-27a/b, miR-210, and miR-454 expression were associated with shorter OS, while the levels of miR-454 and miR-374a/b expression were associated with DFS.

CONCLUSIONS

Specific miRs could serve as potential prognostic biomarkers in TNBC. Due to the limited research available, the clinical application of these findings has yet to be verified.

Clinical Value of miR-101-3p and Biological Analysis of its Prospective Targets in Breast Cancer: A Study Based on The Cancer Genome Atlas (TCGA) and Bioinformatics

Background

MiR-101-3p can promote apoptosis and inhibit proliferation, invasion, and metastasis in breast cancer (BC) cells. However, its mechanisms in BC are not fully understood. Therefore, a comprehensive analysis of the target genes, pathways, and networks of miR-101-3p in BC is necessary.

Material/Methods

The miR-101 profiles for 781 patients with BC from The Cancer Genome Atlas (TCGA) were analyzed. Gene expression profiling of GSE31397 with miR-101-3p transfected MCF-7 cells and scramble control cells was downloaded from Gene Expression Omnibus (GEO), and the differentially expressed genes (DEGs) were identified. The potential genes targeted by miR-101-3p were also predicted. Gene Ontology (GO) and pathway and network analyses were constructed for the DEGs and predicted genes.

Results

In the TCGA data, a low level of miR-101-2 expression might represent a diagnostic (AUC: 0.63) marker, and the miR-101-1 was a prognostic (HR=1.79) marker. MiR-101-1 was linked to the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), and miR-101-2 was associated with the tumor (T), lymph node (N), and metastasis (M) stages of BC. Moreover, 427 genes were selected from the 921 DEGs in GEO and the 7924 potential target genes from the prediction databases. These genes were related to transcription, metabolism, biosynthesis, and proliferation. The results were also significantly enriched in the VEGF, mTOR, focal adhesion, Wnt, and chemokine signaling pathways.

Conclusions

MiR-101-1 and miR-101-2 may be prospective biomarkers for the prognosis and diagnosis of BC, respectively, and are associated with diverse clinical parameters. The target genes of miR-101-3p regulate the development and progression of BC. These results provide insight into the pathogenic mechanism and potential therapies for BC.

Omitting radiation therapy in women with triple-negative breast cancer leads to worse breast cancer-specific survival

PURPOSE

To examine locoregional recurrence (LRR) and breast cancer-specific survival (BCSS) after breast-conserving therapy (BCT) or mastectomy (ME) with or without radiation therapy (RT) in triple-negative breast cancer (TNBC).

MATERIAL & METHODS

We identified non-metastatic TNBC cases from a single institution database. BCT, ME with RT (ME + RT) and ME only were compared with respect to LRR and BCSS. Cox regression models were used to analyze the association between prognostic factors and outcome.

RESULTS

439 patients fulfilled the inclusion criteria. Median follow-up was 10.2 years (interquartile range 7.9; 12.4 years). Patients in the BCT (n = 239), ME + RT (n = 116) and ME only (n = 84) group differed with respect to age, pT, pN, lymphovascular invasion, lymph node dissection and chemotherapy administration. Ten-year LRR rates were seven percent, three percent and eight percent for the BCT, ME + RT and ME only group, respectively. pN was associated with LRR. In multivariable analysis LRR were significantly lower in the ME + RT group compared to the BCT and the ME only group (p 0.037 and 0.020, respectively). Ten year BCSS was 87%, 84% and 75% for the BCT, ME + RT and ME only group, respectively. pT, pN, lymph node dissection, lymphovascular invasion and the administration of chemotherapy were associated with BCSS. In multivariable analysis BCSS was significantly lower in the ME only group compared to the BCT group and the ME + RT group (p 0.047 and 0.003, respectively).

CONCLUSION

TNBC patients treated with ME without adjuvant RT showed significant lower BCSS compared to patients treated with BCT or ME + RT and significant more LRR compared to ME + RT when corrected for known clinicopathological prognostic factors.

MicroRNAs as biomarkers for early breast cancer diagnosis, prognosis and therapy prediction

Breast cancer is a major health problem that affects one in eight women worldwide. As such, detecting breast cancer at an early stage anticipates better disease outcome and prolonged patient survival. Extensive research has shown that microRNA (miRNA) are dysregulated at all stages of breast cancer. miRNA are a class of small noncoding RNA molecules that can modulate gene expression and are easily accessible and quantifiable. This review highlights miRNA as diagnostic, prognostic and therapy predictive biomarkers for early breast cancer with an emphasis on the latter. It also examines the challenges that lie ahead in their use as biomarkers. Noteworthy, this review addresses miRNAs reported in patients with early breast cancer prior to chemotherapy, radiotherapy, surgical procedures or distant metastasis (unless indicated otherwise). In this context, miRNA that are mentioned in this review were significantly modulated using more than one statistical test and/or validated by at least two studies. A standardized protocol for miRNA assessment is proposed starting from sample collection to data analysis that ensures comparative analysis of data and reproducibility of results.

RGD-conjugated mesoporous silica-encapsulated gold nanorods enhance the sensitization of triple-negative breast cancer to megavoltage radiation therapy

Multifunctional nanoprobes have great potential as effective radiosensitizers and drug carriers. RGD-modified gold nanorods could increase the uptake of nanoparticles via receptor-mediated endocytosis in integrin alphaV beta3-overexpressing breast cancer cells, which could enhance the effects of radiation on tumor cells, leading to further radiosensitization. The purpose of our study was to demonstrate that RGD-conjugated mesoporous silica-encapsulated gold nanorods significantly enhanced the sensitization of triple-negative breast cancer to megavoltage energy. The results indicated that RGD-conjugated mesoporous silica-encapsulated gold nanorod multifunctional nanoprobes could achieve radiosensitization in vitro and in vivo, which suggests the potential translation of this nanotechnology to clinical applications in tumor-targeting and selective therapy.

Surgery and radiation therapy of triple-negative breast cancers: From biology to clinics

Triple negative breast cancer refers to tumours lacking the expression of the three most used tumour markers, namely oestrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2 (HER2). These cancers are known to carry a more dismal prognosis than the other molecular subtypes. Whether a more aggressive local-regional treatment is warranted or not in patients with triple-negative breast cancer is still a matter of debate. Indeed there remain a number of grey zones with respect to the optimization of the extent and the timing of surgery and radiation therapy (RT) in this patient population, also in consideration of the significant heterogeneity in biological behaviour and response to treatment identified for these tumours. The objective of this review is to provide an insight into the biological and clinical behaviour of triple-negative breast cancers and revisit the most recent advances in their management, focussing on local-regional treatments.

Methylation Status of SP1 Sites within miR-23a-27a-24-2 Promoter Region Influences Laryngeal Cancer Cell Proliferation and Apoptosis

DNA methylation plays critical roles in regulation of microRNA expression and function. miR-23a-27a-24-2 cluster has various functions and aberrant expression of the cluster is a common event in many cancers. However, whether DNA methylation influences the cluster expression and function is not reported. Here we found a CG-rich region spanning two SP1 sites in the cluster promoter region. The SP1 sites in the cluster were demethylated and methylated in Hep2 cells and HEK293 cells, respectively. Meanwhile, the cluster was significantly upregulated and downregulated in Hep2 cells and HEK293 cells, respectively. The SP1 sites were remethylated and the cluster was significantly downregulated in Hep2 cells into which methyl donor, S-adenosyl-L-methionine, was introduced. Moreover, S-adenosyl-L-methionine significantly increased Hep2 cell viability and repressed Hep2 cell early apoptosis. We also found that construct with two SP1 sites had highest luciferase activity and SP1 specifically bound the gene cluster promoter in vitro. We conclude that demethylated SP1 sites in miR-23a-27a-24-2 cluster upregulate the cluster expression, leading to proliferation promotion and early apoptosis inhibition in laryngeal cancer cells.

Inflamma-miRs in Aging and Breast Cancer: Are They Reliable Players?

Human aging is characterized by chronic low-grade inflammation known as “inflammaging.” Persistent low-level inflammation also plays a key role in all stages of breast cancer since “inflammaging” is the potential link between cancer and aging through NF-kB pathways highly influenced by specific miRs. Micro-RNAs (miRNAs) are small non-coding RNAs that negatively regulate gene expression at a posttranscriptional level. Inflamma-miRs have been implicated in the regulation of immune and inflammatory responses. Their abnormal expression contributes to the chronic pro-inflammatory status documented in normal aging and major age-related diseases (ARDs), inflammaging being a significant mortality risk factor in both cases. Nevertheless, the correct diagnosis of inflammaging is difficult to make and its hidden contribution to negative health outcomes remains unknown. This methodological work flow was aimed at defining crucial unanswered questions about inflammaging that can be used to clarify aging-related miRNAs in serum and cell lines as well as their targets, thus confirming their role in aging and breast cancer tumorigenesis. Moreover, we aim to highlight the links between the pro-inflammatory mechanism underlying the cancer and aging processes and the precise function of certain miRNAs in cellular senescence (CS). In addition, miRNAs and cancer genes represent the basis for new therapeutic findings indicating that both cancer and ARDs genes are possible candidates involved in CS and vice versa. Our goal is to obtain a focused review that could facilitate future approaches in the investigation of the mechanisms by which miRNAs control the aging process by acting as efficient ARDs inflammatory biomarkers. An understanding of the sources and modulation of inflamma-miRs along with the identification of their specific target genes could enhance their therapeutic potential.

Integrated analysis of the miRNA, gene and pathway regulatory network in gastric cancer

Gastric cancer is one of the most common malignant tumors worldwide; however, the efficacy of clinical treatment is limited. MicroRNAs (miRNAs) are a class of small non-coding RNAs that have been reported to play a key role in the development of cancer. They also provide novel candidates for targeted therapy. To date, in-depth studies on the molecular mechanisms of gastric cancer involving miRNAs are still absent. We previously reported that 5 miRNAs were identified as being significantly increased in gastric cancer, and the role of these miRNAs was investigated in the present study. By using bioinformatics tools, we found that more than 4,000 unique genes are potential downstream targets of gastric cancer miRNAs, and these targets belong to the protein class of nucleic acid binding, transcription factor, enzyme modulator, transferase and receptor. Pathway mapping showed that the targets of gastric cancer miRNAs are involved in the MAPK signaling pathway, pathways in cancer, the PI3K-Akt signaling pathway, the HTLV-1 signaling pathway and Ras signaling pathway, thus regulating cell growth, differentiation, apoptosis and metastasis. Analysis of the pathways related to miRNAs may provides potential drug targets for future therapy of gastric cancer.

MiR-185-3p and miR-324-3p Predict Radiosensitivity of Nasopharyngeal Carcinoma and Modulate Cancer Cell Growth and Apoptosis by Targeting SMAD7

Background

MiR-185-3p and miR-324-3p are 2 miRNAs that regulate nasopharyngeal carcinoma (NPC) radioresistance. This study tried to assess the clinical values of low miR-185-3p and low miR-324-3p expression in predicting response to radiotherapy (RT) and prognosis of NPC and to explore their new downstream targets.

Material/Methods

We recruited 80 patients with primary NPC. MiR-185-3p and miR-324-3p expression in the tumor tissues before and after RT or chemoradiotherapy (CRT) were determined. Overall survival and recurrence-free survival curves were estimated to assess the prognostic values of these 2 miRNAs. Their target was predicted using an online database and verified using dual luciferase assay, qRT-PCR, and Western blot analysis. In addition, the function of miR-185-3p/miR-324-3p-SMAD7 axis in NPC cells was investigated.

Results

The expression of miR-185-3p and miR-324-3p was significantly reduced after RT in radioresistant but not in radiosensitive cases. Although miR-185-3p and miR-324-3p are not independent prognostic indicators of overall survival of NPC, their low expression is still associated with poor overall survival and recurrence-free survival. In addition, miR-185-3p and miR-324-3p can modulate growth and apoptosis of NPC cells, partly via SMAD7.

Conclusions

Combined low miR-185-3p and miR-324-3p might be important markers for prediction of low response to RT/CRT and poor overall survival and recurrence-free survival. MiR-185-3p and miR-324-3p can modulate NPC cell growth and apoptosis, at least partly through targeting SMAD7.