Circular RNA circHMCU promotes breast tumorigenesis through miR-4458/PGK1 regulatory cascade

Circular RNAs as a novel molecular mechanism in diagnosis, prognosis, therapeutic target, and inhibiting chemoresistance in breast cancer

Breast cancer (BC) is the most common cancer among women, characterized by significant heterogeneity. Diagnosis of the disease in the early stages and appropriate treatment plays a crucial role for these patients. Despite the available treatments, many patients due to drug resistance do not receive proper treatments. Recently, circular RNAs (circRNAs), a type of non-coding RNAs (ncRNAs), have been discovered to be involved in the progression and resistance to drugs in BC. CircRNAs can promote or inhibit malignant cells by their function. Numerous circRNAs have been discovered to be involved in the proliferation, invasion, and migration of tumor cells, as well as the progression, pathogenesis, tumor metastasis, and drug resistance of BC. Circular RNAs can also serve as a biomarker for diagnosing, predicting prognosis, and targeting therapy. In this review, we present an outline of the variations in circRNAs expression in various BCs, the functional pathways, their impact on the condition, and their uses in clinical applications.

LINC01234 promoted malignant behaviors of breast cancer cells via hsa-miR-30c-2-3p/CCT4/mTOR signaling pathway

OBJECTIVE

Despite continuous progress in treatment, recurrence and metastasis limit further improvement in the prognosis of breast cancer (BC) patients. Our aim was to search for a crucial prognostic biomarker of BC.

MATERIALS AND METHODS

Patient data were selected from The Cancer Genome Atlas (TCGA) and GTEx databases. Several online public databases, including Gene Expression Profiling Interactive Analysis (GEPIA), miRWalk, miRDB, and LncBase Predicted v.2, were used to identify potential upstream miRNAs and lncRNAs. These findings were validated through in vitro experiments.

RESULTS

A total of 1, 097 invasive BC samples and 572 normal breast tissues (including 113 samples from TCGA and 459 samples from GTEx) were collected for the study. CCT4 was not only significantly overexpressed in BC compared with normal breast tissues but also had important prognostic significance (P < 0.001). By intersecting miRWalk and miRDB and conducting correlation analysis, hsa-miR-30c-2-3p was identified as the most probable upstream miRNA of CCT4. Following an extensive assessment that included survival analysis, correlation analysis, and common binding-site prediction, LINC01234 was chosen as the most likely upstream lncRNA. In vitro experiments showed that LINC01234-siRNA inhibited the proliferation, invasion, and migration abilities of BC cells. Western blot analysis further confirmed that LINC01234 promoted malignant behaviors of BC cells via the CCT4/mTOR signaling pathway.

CONCLUSION

The LINC01234/hsa-miR-30c-2-3p/CCT4/mTOR axis was identified as a potential ceRNA regulatory mechanism in BC. These findings established the foundation for systematically unveiling the pathological mechanisms of BC and provided new insights for targeted therapy of BC patients.