HuR inhibition overcomes cFLIP-mediated doxorubicin resistance in triple-negative breast cancer

Area of Science:

• Oncology
• Molecular Biology
• Cancer Research

Background:

• Triple-negative breast cancer (TNBC) poses significant therapeutic challenges due to limited targeted therapies and acquired resistance to chemotherapy.
• Doxorubicin is a key chemotherapy agent, but resistance limits its efficacy in TNBC treatment.

Purpose of the Study:

• To investigate the mechanisms underlying doxorubicin resistance in TNBC.
• To identify a potential strategy to overcome doxorubicin resistance in TNBC.

Main Methods:

• Development of a doxorubicin-resistant TNBC cell subline (231-DR) from MDA-MB-231 cells.
• Assessment of cellular FLICE-inhibitory protein (cFLIP) expression and its role in apoptosis.
• Investigation of the RNA-binding protein Hu antigen R (HuR) in regulating cFLIP expression.
• Evaluation of HuR inhibition using KH-3 or RNA interference on cFLIP levels and chemosensitivity.

Main Results:

• Enhanced cFLIP expression was observed in doxorubicin-resistant 231-DR cells, correlating with resistance to doxorubicin-induced apoptosis.
• siRNA-mediated cFLIP depletion sensitized 231-DR cells to doxorubicin-induced apoptosis.
• HuR was identified as a regulator of cFLIP expression; its inhibition (with KH-3 or RNAi) reduced cFLIP levels.
• KH-3 treatment sensitized TNBC cells to doxorubicin, enhancing apoptosis.

Conclusions:

• cFLIP plays a crucial role in mediating doxorubicin resistance in TNBC.
• HuR acts as a positive regulator of cFLIP expression in TNBC.
• Combining HuR inhibition with doxorubicin represents a promising therapeutic strategy to overcome chemoresistance in TNBC.