The function of MYC in base excision repair protects against RAS-induced senescence

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• MYC and RAS oncogenes cooperate in cell transformation and tumor development.
• MYC prevents RAS-induced senescence, a key factor in tumor progression.
• The precise mechanisms by which MYC prevents senescence and how MYC suppression induces it are not fully understood.

Purpose of the Study:

• To elucidate the role of MYC in preventing RAS-induced senescence.
• To investigate the molecular mechanisms underlying MYC's function in cell proliferation and DNA repair.
• To determine the importance of MYC's DNA repair activity in MYC-RAS cooperation.

Main Methods:

• Investigated the interaction between MYC and Pol β DNA polymerase.
• Assessed the impact of MYC on the base excision repair (BER) pathway.
• Utilized MYC mutants lacking specific domains (e.g., MYCΔCTD) and DNA repair-inactive mutants.
• Examined the effects on RAS-induced senescence and cell transformation in primary cells.

Main Results:

• MYC directly interacts with Pol β, enhancing its enzymatic activity in repairing oxidative DNA damage via BER.
• This MYC-mediated DNA repair allows RAS-driven cancer cells to bypass senescence despite high reactive oxygen species levels.
• The carboxy-terminal domain of MYC is dispensable for its DNA repair function.
• MYC mutants deficient in DNA repair show reduced or no ability to prevent senescence or cooperate with RAS.

Conclusions:

• MYC's function in the base excision repair pathway is critical for its ability to prevent RAS-induced senescence.
• MYC-mediated DNA repair is a key mechanism underlying the cooperation between MYC and RAS in cancer development.
• Targeting MYC's DNA repair function could offer novel therapeutic strategies for MYC-RAS-driven cancers.