RNA-binding protein HuR inhibition induces multiple programmed cell death in breast and prostate cancer

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• The RNA-binding protein Hu antigen R (HuR) is implicated in cancer progression and suppressing cancer cell death.
• The exact mechanisms by which HuR inhibition induces cancer cell death are not fully understood.

Purpose of the Study:

• To investigate the effects of the HuR inhibitor KH-3 on cancer cell proliferation, colony formation, and cell death.
• To elucidate the molecular mechanisms underlying HuR inhibition-induced cell death in various cancer types, particularly breast and prostate cancers.

Main Methods:

• Treatment of multiple cancer cell lines, including breast and prostate cancer cells, with the small molecule inhibitor KH-3.
• Assessment of cell proliferation, colony formation, and various cell death modalities (apoptosis, autophagy, ferroptosis).
• Validation of anti-tumor effects in mouse xenograft models and mechanistic studies involving gene silencing and expression analysis of key targets (cFLIP, SLC7A11, XIAP, Survivin).

Main Results:

• KH-3 induced apoptotic, autophagy-associated, and ferroptosis cell death in diverse cancer cell lines.
• KH-3 treatment partially rescued cell death when combined with autophagy or ferroptosis inhibitors.
• KH-3 reduced the expression of apoptosis suppressor cFLIP and ferroptosis suppressor SLC7A11, and also decreased XIAP and Survivin levels.
• HuR inhibition enhanced caspase activation and PARP cleavage, leading to apoptosis.
• Anti-tumor efficacy of KH-3 was confirmed in prostate cancer xenograft models.

Conclusions:

• HuR plays a critical role in regulating programmed cell death pathways in cancer.
• Inhibition of HuR, as demonstrated with KH-3, represents a promising therapeutic strategy for inducing cancer cell death and treating cancer.