SETD5-Coordinated Chromatin Reprogramming Regulates Adaptive Resistance to Targeted Pancreatic Cancer Therapy

Area of Science:

• Oncology
• Molecular Biology
• Cancer Therapeutics

Background:

• Pancreatic ductal adenocarcinoma (PDAC) exhibits poorly understood adaptive resistance to targeted therapies.
• Understanding resistance mechanisms is crucial for improving PDAC treatment efficacy.

Purpose of the Study:

• To identify molecular drivers of resistance to MEK1/2 inhibition (MEKi) in PDAC.
• To explore therapeutic strategies targeting identified resistance mechanisms.

Main Methods:

• Investigated the role of SETD5 in MEKi resistance using mouse models and patient-derived xenografts.
• Analyzed the SETD5 co-repressor complex, including HDAC3 and G9a.
• Evaluated the efficacy of co-targeting MEK1/2, HDAC3, and G9a.

Main Results:

• SETD5 was identified as a key driver of acquired resistance to MEKi in PDAC.
• SETD5 deletion restored sensitivity to MEKi in resistant PDAC models.
• The SETD5 complex mediates gene silencing, reprogramming cellular responses to MEKi.
• Co-targeting MEK1/2, HDAC3, and G9a demonstrated sustained tumor growth inhibition in vivo.

Conclusions:

• SETD5 is a critical mediator of acquired MEKi therapy resistance in PDAC.
• Targeting SETD5, HDAC3, and G9a offers a potential strategy to overcome MEKi resistance.
• This study provides a rationale for advancing MEKi-based therapies in the clinic for PDAC.