Targeting IKKε in Androgen-Independent Prostate Cancer Causes Phenotypic Senescence and Genomic Instability

Area of Science:

• Oncology
• Molecular Biology
• Cancer Therapeutics

Background:

• Advanced prostate cancer frequently becomes castration-resistant and lethal.
• IKKε expression is linked to prostate cancer aggressiveness.
• IKKε represents a potential therapeutic target for prostate cancer treatment.

Purpose of the Study:

• To investigate the role of IKKε in prostate cancer cell fate.
• To evaluate the therapeutic potential of IKKε inhibitors (BX795, Amlexanox) in prostate cancer models.

Main Methods:

• Depletion of IKKε in PC-3 cells to assess effects on proliferation, cell death, and senescence.
• Treatment of androgen-sensitive and androgen-independent prostate cancer cell lines with IKKε/TBK1 inhibitors.
• Cell-cycle analysis, senescence assays (SA-β-galactosidase), DNA damage assessment (γH2AX), and gene expression analysis (p15, p16, p21).
• In vivo studies using mouse xenograft models of prostate cancer.

Main Results:

• IKKε depletion delayed proliferation and induced senescence in PC-3 cells.
• IKKε inhibitors caused G2-M cell-cycle arrest and increased 8N DNA content specifically in androgen-independent prostate cancer cells.
• Androgen-independent cells showed increased senescence markers, genomic instability, and altered cell cycle regulator expression.
• In vivo, IKKε inhibitors reduced tumor growth in androgen-independent xenografts but not in androgen-sensitive xenografts.

Conclusions:

• Targeting IKKε in androgen-independent prostate cancer induces a senescence phenotype.
• IKKε inhibition demonstrates in vivo antitumor activity against androgen-independent prostate cancer.
• These findings support IKKε as a viable therapeutic target for advanced, castration-resistant prostate cancer.