MicroRNA in combination with HER2-targeting drugs reduces breast cancer cell viability in vitro

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• HER2-positive breast cancer patients unresponsive to targeted therapy face poor prognoses.
• The impact of targeted treatments on endogenous microRNA (miRNA) expression in these cancers remains unclear.
• Responsive HER2-positive breast cancer cell lines exhibit more significant miRNA expression changes post-treatment than less responsive ones.

Purpose of the Study:

• To investigate the role of miRNAs in sensitizing HER2-positive breast cancer cells to targeted therapies.
• To identify specific miRNAs that can enhance the efficacy of trastuzumab and lapatinib treatments.

Main Methods:

• A high-throughput screen of 1626 miRNA mimics and inhibitors was conducted.
• The screen evaluated miRNA combinations with trastuzumab and lapatinib in HER2-positive breast cancer cells.
• Expression levels of miRNAs were analyzed in responsive versus poorly responsive cell lines.

Main Results:

• Eight miRNA mimics were identified as sensitizing HER2-positive breast cancer cells to targeted treatment: miR-101-5p, mir-518a-5p, miR-19b-2-5p, miR-1237-3p, miR-29a-3p, miR-29c-3p, miR-106a-5p, and miR-744-3p.
• Higher expression of miR-101-5p correlated with improved patient prognosis (overall survival and breast cancer-specific survival), suggesting a tumor-suppressive function.
• Responsive cell lines showed a greater number of differentially expressed miRNAs after treatment compared to non-responsive lines.

Conclusions:

• Specific miRNAs can sensitize HER2-positive breast cancer cells to targeted therapies like trastuzumab and lapatinib.
• The identified miRNAs, particularly miR-101-5p, hold potential for improving treatment strategies.
• Combining targeted drugs with miRNA-based therapies may offer a novel approach to enhance treatment efficacy for HER2-positive breast cancer.