miR-7 Reduces Breast Cancer Stem Cell Metastasis via Inhibiting RELA to Decrease ESAM Expression

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Breast cancer stem cells (BCSCs) are crucial drivers of metastasis.
• The precise mechanisms by which miR-7 inhibits BCSCs metastasis are not fully understood.
• Endothelial cell-selective adhesion molecule (ESAM) is implicated in cancer progression.

Purpose of the Study:

• To investigate the inhibitory effect of miR-7 on breast cancer stem cell (BCSC) metastasis.
• To elucidate the underlying molecular mechanisms of miR-7's action.
• To evaluate ESAM as a potential therapeutic target in breast cancer.

Main Methods:

• Protein array analysis of BCSC-driven tumors.
• Dual-luciferase reporter assays and chromatin immunoprecipitation-PCR (ChIP-PCR) to validate molecular targets.
• In vivo studies using mouse models of BCSC-driven xenografts.
• Assessment of miR-7 overexpression effects on metastasis, tumor growth, and specific protein markers.

Main Results:

• miR-7 overexpression significantly reduced BCSCs metastasis in vivo.
• miR-7 directly targets RELA, inhibiting downstream ESAM expression in MDA-MB-231 cells.
• ESAM was highly expressed in breast cancer tissues and xenografts.
• Lentivirus-mediated miR-7 delivery decreased RELA, CD44, and ESAM levels, while increasing E-cadherin and decreasing vimentin in xenografts.
• Tumor growth and lung metastasis were reduced in mice treated with Lenti-miR-7.

Conclusions:

• miR-7 inhibits breast cancer stem cell metastasis by suppressing ESAM expression through the RELA pathway.
• ESAM represents a promising therapeutic target for inhibiting breast cancer progression and metastasis.
• Understanding the miR-7/RELA/ESAM axis provides new insights into breast cancer stem cell biology and therapeutic strategies.