Histone deacetylase inhibitors enhance lexatumumab-induced apoptosis via a p21Cip1-dependent decrease in survivin...

Area of Science:

• Molecular Biology
• Cancer Research
• Immunotherapy

Background:

• Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in cancer cells via TRAIL-R1 and TRAIL-R2.
• Monoclonal antibodies targeting TRAIL receptors are under development for cancer therapy.
• Colon cancer cell sensitivity to TRAIL agonists varies, necessitating strategies to overcome resistance.

Purpose of the Study:

• To investigate the anticancer activity of TRAIL-R1 (mapatumumab) and TRAIL-R2 (lexatumumab) antibodies in colon cancer.
• To explore combination therapies to enhance lexatumumab-induced apoptosis in TRAIL-resistant colon cancer cells.
• To elucidate the molecular mechanisms underlying synergy between lexatumumab and histone deacetylase inhibitors.

Main Methods:

• Treatment of colon cancer cell lines with mapatumumab and lexatumumab.
• Combination therapy using lexatumumab with histone deacetylase inhibitors (trichostatin A, suberoylanilide hydroxamic acid).
• Analysis of p21, p53, survivin, and cdc2 expression and activity; use of flavopiridol and siRNA for survivin knockdown.

Main Results:

• Colon cancer cells express higher TRAIL-R2 than TRAIL-R1 and are more sensitive to lexatumumab.
• Histone deacetylase inhibitors significantly potentiate lexatumumab-induced apoptosis in resistant cells, critically dependent on p21.
• Synergy involves reduced survivin expression and cdc2 activity, with survivin identified as a key mediator of lexatumumab resistance.

Conclusions:

• Lexatumumab demonstrates anticancer activity in colon cancer, particularly in TRAIL-R2 expressing cells.
• Combining lexatumumab with histone deacetylase inhibitors is a promising strategy to overcome TRAIL resistance.
• Targeting survivin, potentially via cdc2 inhibition, enhances lexatumumab efficacy and represents a viable therapeutic approach.