miR-107 Enhances the Sensitivity of Breast Cancer Cells to Paclitaxel

miR-107 and miR-126 and Risk of Breast Cancer: A Case-Control Study

Background: Micro RNAs are new diagnostic markers and therapeutic targets in breast cancer research. miR-107 and miR-126 have been reported to be linked with the pathogenesis of breast cancer. The present study investigates the levels of expression of miR-107 and miR-126 in patients with breast cancer to find their correlation with the risk of breast cancer in Amritsar, Punjab, Northwest India. Material and Methods: In total, 200 subjects, 100 patients with breast cancer and 100 controls, were enrolled to screen the expression of miR-107 and miR-126 using quantitative reverse transcription polymerase chain reaction (RT-PCR) technique. The Livak method (2-ΔΔCt) was used to calculate the fold change of the expression of micro RNAs. Student t-test was used to calculate the significant change in the expression of miRNAs in patients as compared with controls. Spearman rank correlation coefficient and ROC were conducted. The value of p < 0.05 was considered to indicate a statistically significant difference. Results: miR-107 was downregulated in patients with breast cancer as compared with controls (fold change = 0.467; p = 0.114) but not statistically significant. The expression of miR-126 was found to be 5.37 times elevated in patients with breast cancer, specifically in stage I and stage III patients (p = 0.009), compared with controls, which may indicate its oncogenic activity. The ROC analyses revealed that miR-126 could be a potential diagnostic marker. In conclusion oncogenic behavior of miR-126 is suggestive of its role in pathogenesis in patients with breast cancer.

Long noncoding RNA FTX promotes epithelial-mesenchymal transition of epithelial ovarian cancer through modulating miR-7515/TPD52 and activating Met/Akt/mTOR

Overexpressed long noncoding RNA FTX is associated with low survival rate of epithelial ovarian cancer (EOC) patients, and enhances tumor infiltration. Thus, we aim to illuminate the undefined underlying mechanisms. Real-time quantitative polymerase chain reaction was applied to detect the expressions of FTX, miR-7515, miR-342-3p, miR-940, miR-150-5p, miR-205-5p and tumor protein D52 (TPD52). Cell counting kit-8 and transwell assays were utilized to explore the cell viability, migration or invasion of EOC cells. Western blot was conducted to measure the expressions of E-cadherin, N-cadherin, Met, phosphorylated (p)-Met, Akt, p-Akt, mTOR and p-mTOR. LncBase and TargetScan predicted the binding of miR-7515 with FTX, and the binding of TPD52 with miR-7515, respectively. The two bindings were further validated by dual luciferase reporter assay. As a result, FTX sponged miR-7515 and miR-7515 targeted to TPD52. FTX was overexpressed in four EOC cell lines. Overexpressed FTX enhanced the cell viability, migration or invasion of EOC cells, elevated N-cadherin and TPD52 expressions, phosphorylated Met/Akt/mTOR, and inhibited E-cadherin expression. All these influences were subsequently reversed by miR-7515 mimic. Collectively, FTX regulates miR-7515/TPD52 to facilitate the migration, invasion or epithelial-mesenchymal transition of EOC through activating Met/Akt/mTOR signaling pathway.

The discovery of promising candidate biomarkers in kidney renal clear cell carcinoma: evidence from the in-depth analysis of high-throughput data

Kidney renal clear cell carcinoma (KIRC) is the most prevalent subtype of renal tumor. The underlying mechanisms governing KIRC initiation and progression are less known. The present study aimed to reveal novel hub genes associated with the initiation and progression of KIRC, which may be utilized as novel molecular biomarkers and therapeutic targets for the treatment of KIRC. The GSE6344 dataset from the Gene Expression Omnibus (GEO) database was integrated to identify differentially expressed genes (DEGs) using the limma package. Then, hub genes were identified and UALCAN, GEPIA, OncoDB, DriverDBv3, GENT2, and HPA databases were employed for the expression, survival, and methylation analyses. cBioPortal tool was used to investigate the genetic alterations, while CancerSEA, TIMER, DAVID, ENCORI, DrugBank, and GSCAlite were utilized to explore a few more hub gene-associated parameters. Finally, targeted bisulfite sequencing (bisulfite-seq), and RT-qPCR techniques were used to validate the expression and methylation level of the hub genes using Human RCC cell line 786-O, A-498, and normal renal tubular epithelial cell line HK-2. In total, 7299 DEGs were found between KIRC and normal samples in the GSE6344 dataset. Using STRING and Cytohubba analysis, four hub genes including VEGFA (vascular endothelial growth factor), ALB (Albumin), ENO2 (enolase 2), and CAVI1 (Caveolin 1) were selected as the hub genes. Further, it was validated through extensive analysis of TCGA datasets that these VEGA, ENO2, and CAV1 hub genes were significantly up-regulated, while ALB was significantly down-regulated in KIRC samples compared to controls. The dysregulation of these genes was found to be associated with the overall survival (OS) of the KIRC patients. Moreover, this study also revealed some novel links between VEGA, ALB, ENO2, and CAV1 expression and genetic alterations, promoter methylation status, immune cell infiltration, miRNAs, gene enrichment terms, and various chemotherapeutic drugs. The present study revealed a panel of four hub genes, which contributed to improving our understanding of the underlying molecular mechanisms of KIRC development and can be utilized as promising novel biomarkers for KIRC diagnosis, prognosis, and treatment.

High expression of miR-107 and miR-17 predicts poor prognosis and guides treatment selection in acute myeloid leukemia

Background

The prognostic significance of miR-107 and miR-17 in patients with acute myeloid leukemia (AML) remains unclear.

Methods

A total of 173 patients with de novo AML from the Cancer Genome Atlas database were enrolled in this study and further divided into a chemotherapy group (98 cases) and an allogeneic hematopoietic stem cell transplantation (allo-HSCT) group (75 cases) according to their therapy regimen.

Results

In the chemotherapy cohort, high miR-107 or miR-17 expression was associated with poorer overall survival (OS) and event-free survival (EFS). On the other hand, there were no significant differences in OS and EFS between the high- and low-expression subgroups in the allo-HSCT group. Next, we stratified the total number of patients with AML into high- and low-expression groups according to the median expression levels of miR-107 or miR-17. In the high miR-107 or miR-17 expression group, patients treated with allo-HSCT had longer OS than those treated with chemotherapy. In the low miR-107 or miR-17 expression group, no significant differences in OS and EFS were observed between the two therapy subgroups. When patients were further clustered into three groups (both low miR-107 and low miR-17, either high miR-107 or high miR-17, and both high miR-107 and high miR-17), patients with both high miR-107 and high miR-17 expression had the worst OS and EFS of the entire group and of the chemotherapy group. On the other hand, there were no significant differences in OS and EFS among the three subgroups in the allo-HSCT group. Cox regression confirmed the concurrence of high expression of miR-107 and miR-17 might act as an independent prognostic factor for EFS and OS in the entire group and the chemotherapy group. Bioinformatics analysis showed differentially expressed genes (DEGs) associated with miR-107 and miR-17 expression were mainly enriched in multiple metabolic processes.

Conclusions

The combination of miR-107 and miR-17 provides prognostic significance for patients with AML and should be considered in the clinical selection of the optimal treatment regimen when deciding between chemotherapy and allo-HSCT.

Effects of miR-107 on Breast Cancer Cell Growth and Death via Regulation of the PTEN/AKT Signaling Pathway

Objective

Investigate the influence of miR-107 on breast cancer cell growth and death through the PTEN/AKT signaling pathway.

Method

As study subjects, the human breast cancer cell line MCF-7 and the normal breast cell line Hs 578Bst were chosen, and MCF-7 cells were, respectively, transfected with control miRNA and miR-107 inhibitor. CCK-8, flow cytometry, scratch assay, and Transwell assay were used to analyze the proliferation, apoptosis, and invasion, and in order to identify the proteins associated with apoptosis in each of the three categories, we used western blot analysis. Bcl-2, cleaved caspase-3, and cleaved caspase-9 expression, as well as PTEN/AKT signaling pathway-associated protein expression, are correlated.

Result

The expression of miR-107 in MCF-7 cells was significantly greater than that in Hs 578Bst cells, with a P < 0.05 difference; compared to the blank and miRNA control groups, the miR-107 inhibitor group had a P < 0.05 difference. P < 0.05 showed a decrease in proliferation (42.52) but no difference in proliferation between the blank and miRNA control groups (P > 0.05); the miR-107 inhibitor group had higher apoptosis (38.96) with P < 0.05 than the blank group (4.85) and the miRNA control group (5.89); there was no difference in apoptosis between the blank and miRNA groups (P > 0.05). There was no significant difference between the blank group and the miRNA control group with P > 0.05; compared with the blank group, the miR-107 inhibitor group had a lower expression of Bcl-2 protein (0.18), in addition to the degraded paradigms (0.73) and caspase-9 protein concentrations (0.79), respectively.

Conclusion

The PTEN/AKT signaling pathway may be regulated by miR-107 to limit breast cancer cell growth and increase apoptosis, which suggests that miR-107 may be exploited as a tumor marker for therapeutic therapy.

Noncoding RNAs and their therapeutics in paclitaxel chemotherapy: Mechanisms of initiation, progression, and drug sensitivity

The identification of agents that can reverse drug resistance in cancer chemotherapy, and enhance the overall efficacy is of great interest. Paclitaxel (PTX) belongs to taxane family that exerts an antitumor effect by stabilizing microtubules and inhibiting cell cycle progression. However, PTX resistance often develops in tumors due to the overexpression of drug transporters and tumor-promoting pathways. Noncoding RNAs (ncRNAs) are modulators of many processes in cancer cells, such as apoptosis, migration, differentiation, and angiogenesis. In the present study, we summarize the effects of ncRNAs on PTX chemotherapy. MicroRNAs (miRNAs) can have opposite effects on PTX resistance (stimulation or inhibition) via influencing YES1, SK2, MRP1, and STAT3. Moreover, miRNAs modulate the growth and migration rates of tumor cells in regulating PTX efficacy. PIWI-interacting RNAs, small interfering RNAs, and short-hairpin RNAs are other members of ncRNAs regulating PTX sensitivity of cancer cells. Long noncoding RNAs (LncRNAs) are similar to miRNAs and can modulate PTX resistance/sensitivity by their influence on miRNAs and drug efflux transport. The cytotoxicity of PTX against tumor cells can also be affected by circular RNAs (circRNAs) and limitation is that oncogenic circRNAs have been emphasized and experiments should also focus on onco-suppressor circRNAs.

PCAT6 May Be a Whistler and Checkpoint Target for Precision Therapy in Human Cancers

Simple Summary

Prostate cancer-associated transcript 6 (PCAT6), as a newly discovered carcinogenic long non-coding RNA (lncRNA), is abnormally expressed in multiple diseases. With the accumulation of studies on PCAT6, we have a deeper understanding of its biological functions and mechanisms. Therefore, in this review, the various molecular mechanisms by which PCAT6 promotes multiple tumorigenesis and progression are summarized and discussed. Furthermore, its potential diagnostic, prognostic, and immunotherapeutic values are also clarified.

Abstract

LncRNAs are involved in the occurrence and progressions of multiple cancers. Emerging evidence has shown that PCAT6, a newly discovered carcinogenic lncRNA, is abnormally elevated in various human malignant tumors. Until now, PCAT6 has been found to sponge various miRNAs to activate the signaling pathways, which further affects tumor cell proliferation, migration, invasion, cycle, apoptosis, radioresistance, and chemoresistance. Moreover, PCAT6 has been shown to exert biological functions beyond ceRNAs. In this review, we summarize the biological characteristics of PCAT6 in a variety of human malignancies and describe the biological mechanisms by which PCAT6 can facilitate tumor progression. Finally, we discuss its diagnostic and prognostic values and clinical applications in various human malignancies.

Exosomal microRNA-107 reverses chemotherapeutic drug resistance of gastric cancer cells through HMGA2/mTOR/P-gp pathway

Background

RNA cargo in exosomes, especially microRNAs (miRNAs), play an important role in the chemotherapy drug resistance of human cancers. However, the role and mechanism of exosomal miR-107 on multidrug resistance of gastric cancer cells was still not clear. In this study, we sought to explore whether exosomal miR-107 could reverse the resistance of gastric cancer cells to the chemotherapy drugs.

Methods

We extracted exosomes from sensitive (SGC-7901, MGC-803) and resistant (SGC-7901/5-FU) gastric cancer cells by ultracentrifugation and the isolated exosomes were identified using transmission electron microscopy (TEM) and dynamic light scattering analysis (DLS). The expression of miR-107 and high mobility group A2 (HMGA2) were detected by real-time quantitative PCR (RT-qPCR). MTT assay was used to investigate the effect of exosomes on gastric cancer cells growth in vitro. The uptake of exosomes by recipient cells were observed using a fluorescence microscope. The predicted target relationship between miR-107 and HMGA2 was verified by gauss-luciferase reporter assay. The expression of HMGA2, p-mTOR/mTOR, P-gp and other exosomal indicated marker proteins was detected by western blot.

Results

Our results indicated that the isolated exosomes were typically cup-like lipid bilayer membranes structure. SGC-7901/5-FU cells were cross-resistant to chemotherapy drug cisplatin (CDDP), and the sensitive cells-secreted exosomes drastically reversed the resistance of the resistant GC cells to the chemotherapeutic drugs, which was verified by exosomal inhibitor GW4896. Mechanistically, the reversal effect was mainly mediated by exosome-secreted miR-107 through downregulating the expression of target molecular HMGA2 and inhibiting HMGA2/mTOR/P-gp pathway, which were supported by results from luciferase reporter assay and rescue assay.

Conclusions

These findings demonstrated that exosome-transmitted miR-107 significantly enhanced the sensitivity of resistant gastric cancer cells to chemotherapeutic agents by mediating the HMGA2/mTOR/P-gp axis and exosomal miR-107 may be a novel target in gastric cancers treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-09020-y.

Contribution of miRNAs in the Pathogenesis of Breast Cancer

Breast cancer is the most frequently diagnosed cancer among females. Gene expression profiling methods have shown the deregulation of several genes in breast cancer samples and have confirmed the heterogeneous nature of breast cancer at the genomic level. microRNAs (miRNAs) are among the recently appreciated contributors in breast carcinogenic processes. These small-sized transcripts have been shown to partake in breast carcinogenesis through modulation of apoptosis, autophagy, and epithelial-mesenchymal transition. Moreover, they can confer resistance to chemotherapy. Based on the contribution of miRNAs in almost all fundamental aspects of breast carcinogenesis, therapeutic intervention with their expression might affect the course of this disorder. Moreover, the presence of miRNAs in the peripheral blood of patients potentiates these transcripts as tools for non-invasive diagnosis of breast cancer.

MicroRNAs as a clue to overcome breast cancer treatment resistance

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

Hsa-miR-107 regulates chemosensitivity and inhibits tumor growth in hepatocellular carcinoma cells

Hepatocellular carcinoma is a common type of liver cancer. Resistance to chemotherapeutic agents is a major problem in cancer therapy. MicroRNAs have been reported in cancer development and tumor growth; however, the relationship between chemoresistance and hepatocellular carcinoma needs to be fully investigated. Here, we treated hepatocellular carcinoma cell line (HA22T) with a histone deacetylase inhibitor to establish hepatocellular carcinoma-resistant cells (HDACi-R) and investigated the molecular mechanisms of chemoresistance in HCC cells. Although histone deacetylase inhibitor could not enhance cell death in HDACi-R but upregulation of miR-107 decreased cell viability both in parental cells and resistance cells, decreased the expression of cofilin-1, enhanced ROS-induced cell apoptosis, and dose-dependently sensitized HDACi-R to HDACi. Further, miR-107 upregulation resulted in tumor cell disorganization in both HA22T and HDACi-R in a mice xenograft model. Our findings demonstrated that miR-107 downregulation leads to hepatocellular carcinoma cell resistance in HDACi via a cofilin-1-dependent molecular mechanism and ROS accumulation.

Role of non-coding RNAs in modulating the response of cancer cells to paclitaxel treatment

Paclitaxel is a chemotherapeutic substance that is administered for treatment of an extensive spectrum of human malignancies. In spite of its potent short-term effects against tumor cells, resistance to paclitaxel occurs in a number of patients precluding its long-term application in these patients. Non-coding RNAs have been shown to influence response of cancer cells to this chemotherapeutic agent via different mechanisms. Mechanistically, these transcripts regulate expression of several genes particularly those being involved in the apoptotic processes. Lots of in vivo and in vitro assays have demonstrated the efficacy of oligonucleotide-mediated microRNAs (miRNA)/ long non-coding RNAs (lncRNA) silencing in enhancement of response of cancer cells to paclitaxel. Therefore, targeted therapies against non-coding RNAs have been suggested as applicable modalities for combatting resistance to this agent. In the present review, we provide a summary of studies which assessed the role of miRNAs and lncRNAs in conferring resistance to paclitaxel.

Paclitaxel exposure downregulates miR-522 expression and its downregulation induces paclitaxel resistance in ovarian cancer cells

Paclitaxel resistance is a critical challenge in ovarian cancer treatment. This study aimed to identify microRNAs (miRNAs) that modulate paclitaxel resistance for use as potential therapeutic targets in such settings. Paclitaxel-resistant cell lines were established using two ovarian cancer cell lines: SKOV3ip1 and HeyA8. The evaluation of miRNA polymerase chain reaction (PCR) arrays indicated that the expression of miR-522-3p was downregulated in paclitaxel-resistant cells. The restoration of miR-522-3p sensitized the resistant cells to paclitaxel, and its downregulation desensitized the parental cells. Using PCR arrays, we focused on E2F2, with the luciferase reporter assay revealing that it was a direct target for miR-522-3p. The paclitaxel-resistant cells showed stronger E2F2 expression than the parental cells, while E2F2 inhibition sensitized the resistant cells to paclitaxel. Forced E2F2 expression in the parental cells led to the acquisition of paclitaxel resistance, while miR-522-3p inhibited E2F2 expression and was associated with retinoblastoma protein phosphorylation attenuation, which resulted in G0/G1 arrest. The effects of miR-522-3p and E2F2 in ovarian cancer were examined using public databases, revealing that low miR-522-3p expression and high E2F2 expression were associated with significantly poorer overall survival. In conclusion, miR-522-3p attenuated the degree of paclitaxel resistance in vitro through the downregulation of E2F2; miR-522-3p supplementation may be a therapeutic target for paclitaxel-resistant ovarian cancer.

Circ_0006528 Contributes to Paclitaxel Resistance of Breast Cancer Cells by Regulating miR-1299/CDK8 Axis

Background

Circular RNAs (circRNAs) have been reported to be involved in regulating the development of breast cancer. Paclitaxel (PTX) can be used for the chemotherapy of breast cancer. The study aimed to explore the role and mechanism of circ_0006528 in PTX-resistant breast cancer progression.

Methods

The levels of circ_0006528, microRNA-1299 (miR-1299) and cyclin-dependent kinase 8 (CDK8) were measured by quantitative real-time polymerase chain reaction (qRT-PCR). RNase R treatment was used to confirm that the circ_0006528 was a circular RNA. PTX resistance and cell proliferation were determined by Cell counting kit-8 (CCK-8) assay. Cell apoptosis, migration and invasion were analyzed by flow cytometry and Transwell assays, respectively. The levels of all proteins were examined by Western blot. The interaction between circ_0006528 and miR-1299 or CDK8 was predicted by online database confirmed by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Xenograft mice model was constructed to reveal the role of circ_0006528 on tumor growth in vivo.

Results

Circ_0006528 was significantly up-regulated and miR-1299 was down-regulated in PTX-resistant breast cancer tissues and cells compared with control groups. CDK8 protein expression was dramatically upregulated in PTX-resistant breast cancer tissues and cells as compared to control groups. Loss-of-function experiments revealed that circ_0006528 knockdown decreased IC50 value of PTX and restrained proliferation, migration, invasion and autophagy, whereas induced apoptosis of PTX-resistant breast cancer cells in vitro. The inhibitory effects of sh-circ_0006528 on the progression of PTX-resistant breast cancer cells were reversed by decreasing miR-1299 or increasing CDK8 expression. Furthermore, circ_0006528 could modulate CDK8 expression by sponging miR-1299. Circ_0006528 silencing impeded the growth of PTX-resistant tumors by regulating miR-1299/CDK8 axis in vivo.

Conclusion

Circ_0006528 partially contributed to PTX resistance of breast cancer cells through up-regulating CDK8 expression by sponging miR-1299.

Targeting micro-RNAs by natural products: a novel future therapeutic strategy to combat cancer

MicroRNAs are a class of short, non-coding RNAs that play a crucial role in normal physiology by attenuating translation or targeting messenger RNAs for degradation. Deregulation of miRNAs disturbs key molecular events in interconnected processes such as cell proliferation, tumor angiogenesis, self-renewal, apoptosis, metastasis and epithelial to mesenchymal transition. This process initiates, promotes and develops the pathophysiology of cancer. The modulation of miRNAs results in epigenetic changes in the genome, which eventually leads to cancer. Targeting deregulated miRNAs by natural products derived from plants is an ideal strategy to combat tumorigenesis. Owing to their fewer side effects, natural products have been used as chemotherapeutic agents against various cancers. These natural products modulate the dysregulated signaling pathways by downregulating the oncogenic miRNAs which play a crucial role in the development of tumorigenesis and maintain a fine balance of tumor suppressor miRNAs. This review article aims to highlight the key modifications of miRNAs which lead to tumorigenesis and the chemotherapeutic potential of natural products by targeting miRNAs and their possible mechanism of inhibition for developing an effective anti-cancer agent(s). They will have less damaging effects on normal cells for future chemotherapeutics.

Potential miRNAs for miRNA-Based Therapeutics in Breast Cancer

MicroRNAs (miRNAs) are small non-coding RNAs that can post-transcriptionally regulate the genes involved in critical cellular processes. The aberrant expressions of oncogenic or tumor suppressor miRNAs have been associated with cancer progression and malignancies. This resulted in the dysregulation of signaling pathways involved in cell proliferation, apoptosis and survival, metastasis, cancer recurrence and chemoresistance. In this review, we will first (i) provide an overview of the miRNA biogenesis pathways, and in vitro and in vivo models for research, (ii) summarize the most recent findings on the roles of microRNAs (miRNAs) that could potentially be used for miRNA-based therapy in the treatment of breast cancer and (iii) discuss the various therapeutic applications.

MicroRNAs in cancer therapy: Their involvement in oxaliplatin sensitivity/resistance of cancer cells with a focus on colorectal cancer

The resistance of cancer cells into chemotherapy has restricted the efficiency of anti-tumor drugs. Oxaliplatin (OX) being an anti-tumor agent/drug is extensively used in the treatment of various cancer diseases. However, its frequent application has led to chemoresistance. As a consequence, studies have focused in finding underlying molecular pathways involved in OX resistance. MicroRNAs (miRs) are short endogenous non-coding RNAs that are able to regulate vital biological mechanisms such as cell proliferation and cell growth. The abnormal expression of miRs occurs in pathological events, particularly cancer. In the present review, we describe the involvement of miRs in OX resistance and sensitivity. The miRs are able to induce the oncogene factors and mechanisms, resulting in stimulation OX chemoresistance. Also, onco-suppressor miRs can enhance the sensitivity of cancer cells into OX chemotherapy and trigger apoptosis and cell cycle arrest, leading to reduced viability and progression of cancer cells. MiRs can also enhance the efficacy of OX chemotherapy. It is worth mentioning that miRs affect various down-stream targets in OX resistance/sensitivity such as STAT3, TGF-β, ATG4B, FOXO1, LATS2, NF-κB and so on. By identification of these miRs and their upstream and down-stream mediators, further studies can focus on targeting them to sensitize cancer cells into OX chemotherapy and induce apoptotic cell death.

Cell-free miRNAs as non-invasive biomarkers in breast cancer: Significance in early diagnosis and metastasis prediction

Breast cancer is one of the genetic diseases causing a high mortality among women around the world. Despite the availability of advanced diagnostic tools and treatment strategies, the incidence of breast cancer is increasing every year. This is due to the lack of accurate and reliable biomarkers whose deficiency creates difficulty in early breast cancer recognition, subtypes determination, and metastasis prophecy. Although biomarkers such as ER, PR, Her2, Ki-67, and other genetic platforms e.g. MammaPrint®, Oncotype DX®, Prosigna® or EndoPredict® are available for determination of breast cancer diagnosis and prognosis. However, pertaining to heterogeneous nature, lack of sensitivity, and specificity of these markers, it is still incessant to overcome breast cancer burden. Therefore, a novel biomarker is urgently needed for therapeutic diagnosis and improving prognosis. Lately, it has become more evident that cell-free miRNAs might be useful as good non-invasive biomarkers that are associated with different events in carcinogenesis. For example, some known biomarkers such as miR-21, miR-23a, miR-34a are associated with molecular subtyping and different biomolecular aspects i.e. apoptosis, angiogenesis, metastasis, and miR-1, miR-10b, miR-16 are associated with drug response. Cell-free miRNAs present in human body fluids have proven to be potential biomarkers with significant prognostic and predictive values. Numerous studies have found a distinct expression profile of circulating miRNAs in breast tumour versus non-tumour and in early and advanced-stage, thus implicating its clinical relevance. This review article will highlight the importance of different cell-free miRNAs as a biomarker for early breast cancer detection, subtype classification, and metastasis forecast.