Prognostic Implications of microRNA-155, -133a, -21 and -205 in Breast Cancer Patients' Plasma

The role of circRNAs and miRNAs in drug resistance and targeted therapy responses in breast cancer

MicroRNAs (miRNAs) are small non-coding RNAs comprising 19-24 nucleotides that indirectly control gene expression. In contrast to other non-coding RNAs (ncRNAs), circular RNAs (circRNAs) are defined by their covalently closed loops, forming covalent bonds between the 3' and 5' ends. circRNAs regulate gene expression by interacting with miRNAs at transcriptional or post-transcriptional levels. Accordingly, circRNAs and miRNAs control many biological events related to cancer, including cell proliferation, metabolism, cell cycle, and apoptosis. Both circRNAs and miRNAs are involved in the pathogenesis of diseases, such as breast cancer. This review focuses on the latest discoveries on dysregulated circRNAs and miRNAs related to breast cancer, highlighting their potential as biomarkers for clinical diagnosis, prognosis, and chemotherapy response.

Identification of a glycolysis-related miRNA Signature for Predicting Breast cancer Survival

Breast cancer (BC) is a common type of cancer and has a poor prognosis. In this study, we collected the mRNA and miRNA expression profiles of BC patients were obtained from The Cancer Genome Atlas (TCGA) to explore a novel prognostic strategy for BC patients using bioinformatics tools. We found that six glycolysis-related miRNAs (GRmiRs, including hsa-mir-1247, hsa-mir148b, hsa-mir-133a-2, has-mir-1307, hsa-mir-195 and hsa-mir-1258) were correlated with prognosis of BC samples. The risk score model was established based on 6 prognosis-associated GRmiRs. The outcome of high risk group was significantly poorer. Cox regression analysis showed that risk score was an independent prognostic factor. Differentially expressed genes identified between high and low risk groups were mainly enriched in inflammation and immune-related signaling pathways. The proportion of infiltration of 12 kinds of immune cells in high and low risk groups were significantly different. Risk score was closely associated with many immune indexes. Multiple DEGRGs and miRNAs were associated with drugs. In conclusion, glycolysis-related miRNA signature effectively predicts BC prognosis.

Unlocking the Potential of Circulating miRNAs in the Breast Cancer Neoadjuvant Setting: A Systematic Review and Meta-Analysis

The potential role of circulating microRNAs (miRNAs) as biomarkers in breast cancer (BC) management has been widely reported. However, the numerous discrepancies between studies in this regard hinders the implementation of circulating miRNAs in routine clinical practice. In the context of BC patients undergoing neoadjuvant chemotherapy (NAC), the possibility of predicting NAC response may lead to prognostic improvements by individualizing post-neoadjuvant therapy. In this context, the present meta-analysis aims to clarify circulating miRNAs' predictive role with respect to NAC response among BC patients. We conducted a comprehensive literature search on five medical databases until 16 February 2023. We pooled the effect sizes of each study by applying a random-effects model. Cochran's Q test (p-level of significance set at 0.05) scores and I² values were assessed to determine between-study heterogeneity. The PROBAST (Prediction Model Risk of Bias Assessment Tool) tool was used to evaluate the selected studies' risk of bias. Overall, our findings support the hypothesis that circulating miRNAs, specifically miR-21-5p and miR-155-5p, may act as predictive biomarkers in the neoadjuvant setting among BC patients. However, due to the limited number of studies included in this meta-analysis and the high degrees of clinical and statistical heterogeneity, further research is required to confirm the predictive power of circulating miR-21-5p and miR-155-5p.

hsa-mir-133a-2 promotes the proliferation and invasion of cervical cancer cells by targeting the LAMB3-mediated PI3K/ATK pathway

OBJECTIVE

Cervical cancer, one of the common types of malignant tumors progressed in women, is on the rise in developing countries. Numerous previous studies have demonstrated that hsa-mir-133a-2 miRNA is abnormally expressed in cervical cancer cells. However, its fundamental mechanism in cervical cancer needs to be further clarified. Our study set out to investigate the effect of hsa-mir-133a-2 on the phenotypes of cervical cancer cells as well as any potential molecular processes involved in the proliferation and invasion of cervical cancer cells.

METHODS

The Cancer Genome Atlas-cervical squamous cell carcinoma and endocervical adenocarcinoma(TCGA-CESC) was adopted in order to verify the expression of hsa-mir-133a-2 in cervical cancer tissues and to identify its potential targets. The interaction between Laminin subunit beta-3(LAMB3) and hsa-mir-133a-2 was verified by TargetScan database as well as Luciferase reporter assay. The Cell Counting Kit-8 (CCK8) and transwell methods were utilized to assess the influence of hsa-mir-133a-2 on the proliferation and invasion characteristics of cervical cancer cells. We studied the role that hsa-mir-133a-2 plays in cervical cancer progression through Kyoto Encyclopedia of Genes and Genomes(KEGG) analysis as well as Western Blot (WB) experiment.

RESULTS

Down-regulation of hsa-mir-133a-2 was detected in cervical cancer tissues. It directly targeted LAMB3 and negatively regulated LAMB3 expression. The overexpression of hsa-mir-133a-2 has a significant inhibiting effect on cervical cancer cell proliferation and invasion. The overexpression of hsa-mir-133a-2 significantly inhibits the proliferation and invasion of cervical cancer cells. Moreover, the LAMB3 was able to up-regulate the phosphorylation levels of AKT and phosphatidylinositol 3-kinase (PI3K) protein in cervical cancer cells. hsa-mir-133a-2 could also modulate the PI3K/AKT signaling pathway by targeting LAMB3.

CONCLUSION

hsa-mir-133a-2 inhibits cervical cancer cell proliferation and invasion by indirectly regulating the PI3K/AKT signaling pathway, providing us with a new clinical treatment strategy for cervical cancer.