miR-200c increases the sensitivity of breast cancer cells to Doxorubicin through downregulating MDR1 gene

Enhancing Chemotherapy Efficacy: Investigating the Synergistic Impact of Paclitaxel and cd73 Gene Suppression on Breast Cancer Cell Proliferation and Migration

Background Enhancing chemotherapy efficacy is crucial in breast cancer treatment. This study examines the synergistic effects of paclitaxel, a common chemotherapeutic drug, and Cluster of differentiation 73 (cd73) gene suppression via siRNA on MDA-MB-231 breast cancer cells. Methods MDA-MB-231 cells were transfected with CD73 siRNA and treated with paclitaxel. Cell viability, apoptosis, and migration were assessed by using MTT assays, Annexin V-FITC/PI staining, and wound healing assays, respectively, with flow cytometry analyzing cell cycle distribution. Results The combination of CD73 siRNA and paclitaxel significantly reduced cell viability, lowering paclitaxel's IC50 from 14.73 μg/mL to 8.471 μg/mL, indicating enhanced drug sensitivity. Apoptosis rates increased with the combination treatment, while cell migration was significantly inhibited. Flow cytometry revealed cell cycle arrest in the Sub-G1 and G2-M phases. Conclusion These findings suggest that cd73 gene suppression enhances paclitaxel's cytotoxic effects, promoting apoptosis and inhibiting cell migration in MDA-MB-231 breast cancer cell line. This combined strategy shows promise for improving breast cancer treatment outcomes by increasing the efficacy of existing chemotherapeutic regimens, warranting further research to explore its potential clinical applications and effectiveness in other breast cancer cell lines and models.

Liquid biopsy utilizing miRNA in patients with advanced breast cancer treated with cyclin‑dependent kinase 4/6 inhibitors

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6is) are the mainstay of treatment of hormone receptor+/human epidermal growth factor receptor 2-patients with advanced breast cancer (ABC). Despite improvements in overall survival, most patients experience disease progression. Biomarkers derived from a liquid biopsy are appealing for their potential to detect resistance to treatment earlier than computed tomography imaging. However, clinical data concerning microRNAs (miRNAs/miRs) in the context of CDK4/6is are lacking. Thus, the present study assessed the use of miRNAs in patients with ABC treated with CDK4/6is. Patients treated for ABC with CDK4/6is between June and August 2022 were eligible. miRNA expression analyses were performed using a TaqMan™ low-density miRNA array. A total of 80 consecutive patients with ABC treated with CDK4/6is at Maria Sklodowska-Curie National Research Institute of Oncology (Gliwice, Poland) were assessed, with 14 patients diagnosed with progressive disease at the time of sampling, 55 patients exhibited clinical benefit from CDK4/6i treatment and 11 patients were at the beginning of CDK4/6i treatment. Patients with disease progression had significantly higher levels of miR-21 (P=0.027), miR-34a (P=0.011), miR-193b (P=0.032), miR-200a (P=0.027) and miR-200b (P=0.003) compared with patients who benefitted from CDK4/6i treatment. Significantly higher levels of miR-34a expression were observed in patients with progressive disease than in patients beginning treatment (P=0.031). The present study demonstrated the potential innovative role of circulating miRNAs during CDK4/6i treatment. Plasma-based expression of miR-21, -34a, -193b, -200a and -200b effectively distinguished patients with ABC who responded to CDK4/6i treatment from patients who were resistant. However, longitudinal studies are required to verify the predictive and prognostic potential of miRNA.

Therapeutic effect of microRNA-21 on differentially expressed hub genes in gastric cancer based on systems biology

Gastric cancer (GC) is a leading cause of mortality for many people. Cancer's initiating factors are poorly understood. miR-21 has a crucial function in several malignancies, particularly GC. Furthermore, it has been shown that miR-21 is critical for the emergence and advancement of GC. This work intends to identify new genes which expression is associated with the activity of mir-21 in GC and to investigate the effect of downregulation of mir-21 on these genes and gastric tumorigenesis. We utilized the gene expression profiles of GCs from an Array database (GSE13911) from the Gene Expression Omnibus (GEO) dataset to find differentially expressed genes (DEGs) between control and gastric cancer groups. Using weighted gene correlation network analysis (WGCNA) in R, the Gene co-expression network was reconstructed. The microRNA-mRNA network was then reconstructed using the miRWalk database, and by investigating the microRNA-mRNA network, the genes that have an association with mir-21 were found. To implement the functional investigation, MKN and AGS cell lines were transfected with anti-miR-21 next. Subsequently, MTT proliferation was utilized to assess the cell's vitality. qRT-PCR was then used to evaluate the anticipated levels of gene expression in both GC cell lines. This study discovered and predicted CCL28, NR3C2, and SNYPO2 as the targets of miR-21 (GC), which are downregulated through gastric tumorigenesis, showing great potential as therapeutic and diagnostic targets. The suppression of miR-21 in gastric GC cells led to the inhibition of cell proliferation and decreased expression of CCL28, NR3C2, and SNYPO2 genes. This study established that miR-21, via downregulating these genes, contributes significantly to the development of GC. In addition, systems biology techniques identified CCL28, NR3C2, and SNYPO2 genes as possible GC surveillance and therapy components.

miRNAs as short non-coding RNAs in regulating doxorubicin resistance

The treatment of cancer patients has been prohibited by chemoresistance. Doxorubicin (DOX) is an anti-tumor compound disrupting proliferation and triggering cell cycle arrest via inhibiting activity of topoisomerase I and II. miRNAs are endogenous RNAs localized in cytoplasm to reduce gene level. Abnormal expression of miRNAs changes DOX cytotoxicity. Overexpression of tumor-promoting miRNAs induces DOX resistance, while tumor-suppressor miRNAs inhibit DOX resistance. The miRNA-mediated regulation of cell death and hallmarks of cancer can affect response to DOX chemotherapy in tumor cells. The transporters such as P-glycoprotein are regulated by miRNAs in DOX chemotherapy. Upstream mediators including lncRNAs and circRNAs target miRNAs in affecting capacity of DOX. The response to DOX chemotherapy can be facilitated after administration of agents that are mostly phytochemicals including curcumol, honokiol and ursolic acid. These agents can regulate miRNA expression increasing DOX's cytotoxicity. Since delivery of DOX alone or in combination with other drugs and genes can cause synergistic impact, the nanoparticles have been introduced for drug sensitivity. The non-coding RNAs determine the response of tumor cells to doxorubicin chemotherapy. microRNAs play a key role in this case and they can be sponged by lncRNAs and circRNAs, showing interaction among non-coding RNAs in the regulation of doxorubicin sensitivity.

MicroRNAs as Molecular Biomarkers for the Characterization of Basal-like Breast Tumor Subtype

Breast cancer is a heterogeneous disease highlighted by the presence of multiple tumor variants and the basal-like breast cancer (BLBC) is considered to be the most aggressive variant with limited therapeutics and a poor prognosis. Though the absence of detectable protein and hormonal receptors as biomarkers hinders early detection, the integration of genomic and transcriptomic profiling led to the identification of additional variants in BLBC. The high-throughput analysis of tissue-specific micro-ribonucleic acids (microRNAs/miRNAs) that are deemed to have a significant role in the development of breast cancer also displayed distinct expression profiles in each subtype of breast cancer and thus emerged to be a robust approach for the precise characterization of the BLBC subtypes. The classification schematic of breast cancer is still a fluid entity that continues to evolve alongside technological advancement, and the transcriptomic profiling of tissue-specific microRNAs is projected to aid in the substratification and diagnosis of the BLBC tumor subtype. In this review, we summarize the current knowledge on breast tumor classification, aim to collect comprehensive evidence based on the microRNA expression profiles, and explore their potential as prospective biomarkers of BLBC.

Advances in the structure, mechanism and targeting of chemoresistance-linked ABC transporters

Cancer cells frequently display intrinsic or acquired resistance to chemically diverse anticancer drugs, limiting therapeutic success. Among the main mechanisms of this multidrug resistance is the overexpression of ATP-binding cassette (ABC) transporters that mediate drug efflux, and, specifically, ABCB1, ABCG2 and ABCC1 are known to cause cancer chemoresistance. High-resolution structures, biophysical and in silico studies have led to tremendous progress in understanding the mechanism of drug transport by these ABC transporters, and several promising therapies, including irradiation-based immune and thermal therapies, and nanomedicine have been used to overcome ABC transporter-mediated cancer chemoresistance. In this Review, we highlight the progress achieved in the past 5 years on the three transporters, ABCB1, ABCG2 and ABCC1, that are known to be of clinical importance. We address the molecular basis of their broad substrate specificity gleaned from structural information and discuss novel approaches to block the function of ABC transporters. Furthermore, genetic modification of ABC transporters by CRISPR-Cas9 and approaches to re-engineer amino acid sequences to change the direction of transport from efflux to import are briefly discussed. We suggest that current information regarding the structure, mechanism and regulation of ABC transporters should be used in clinical trials to improve the efficiency of chemotherapeutics for patients with cancer.

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

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

miRNAs: Potential as Biomarkers and Therapeutic Targets for Cancer

MicroRNAs (miRNAs) are single-stranded, non-coding RNA molecules that regulate gene expression post-transcriptionally by binding to messenger RNAs. miRNAs are important regulators of gene expression, and their dysregulation is implicated in many human and canine diseases. Most cancers tested to date have been shown to express altered miRNA levels, which indicates their potential importance in the oncogenic process. Based on this evidence, numerous miRNAs have been suggested as potential cancer biomarkers for both diagnosis and prognosis. miRNA-based therapies have also been tested in different cancers and have provided measurable clinical benefits to patients. In addition, understanding miRNA biogenesis and regulatory mechanisms in cancer can provide important knowledge about resistance to chemotherapies, leading to more personalized cancer treatment. In this review, we comprehensively summarized the importance of miRNA in human and canine cancer research. We discussed the current state of development and potential for the miRNA as both a diagnostic marker and a therapeutic target.

LINC01234 Accelerates the Progression of Breast Cancer via the miR-525-5p/Cold Shock Domain-Containing E1 Axis

Backgrounds. Long noncoding RNAs (lncRNAs) are strongly associated with the development of breast cancer (BC). As yet, the function of LINC01234 in BC remains unknown. Methods. Using biological information, the potential lncRNA, miRNA, and target gene were predicted. LINC01234 and miR-525-5p expression in BC tissues was detected using quantitative real-time reverse transcription polymerase chain reaction. Fluorescence in situ hybridization was used to determine the distribution of LINC01234. Cell proliferation was analyzed using CCK-8 assay, colony formation, terminal deoxynucleotidyl transferase dUTP nick end labeling staining, and apoptosis evaluated using flow cytometry. Western blotting was used to evaluate protein expression. Dual-luciferase® reporter, RNA pull-down, and RNA immunoprecipitation assays were performed to analyze the binding relationships among LINC01234, miR-525-5p, and cold shock domain-containing E1 (CSDE1). Results. We screened out LINC01234, found to be significantly increased in BC tissues, associated with a poor prognosis, and positively correlated with tumor size of BC. Knockdown of LINC01234 suppressed BC cell growth and facilitated apoptosis. Dual-luciferase reporter®, RNA pull-down, and RNA immunoprecipitation assays confirmed that LINC01234 and CSDE1 directly interacted with miR-525-5p. Upregulation of miR-525-5p and suppression of CSDE1 inhibited BC cell growth and induced cell apoptosis. Conclusion. Upregulation of LINC01234 contributes to the development of BC through the miR-525-5p/CSDE1 axis. LINC01234 may be one of the potential diagnostic and treatment targets for BC.

MicroRNA as a Potential Therapeutic Molecule in Cancer

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