Targeting the DNA replication stress phenotype of KRAS mutant cancer cells

TY - JOUR

T1 - Targeting the DNA replication stress phenotype of KRAS mutant cancer cells

AU - Al Zubaidi, Tara

AU - Gehrisch, O H Fiete

AU - Genois, Marie-Michelle

AU - Liu, Qi

AU - Lu, Shan

AU - Kung, Jong

AU - Xie, Yunhe

AU - Schuemann, Jan

AU - Lu, Hsiao-Ming

AU - Hata, Aaron N

AU - Zou, Lee

AU - Borgmann, Kerstin

AU - Willers, Henning

PY - 2021/2/11

Y1 - 2021/2/11

N2 - Mutant KRAS is a common tumor driver and frequently confers resistance to anti-cancer treatments such as radiation. DNA replication stress in these tumors may constitute a therapeutic liability but is poorly understood. Here, using single-molecule DNA fiber analysis, we first characterized baseline replication stress in a panel of unperturbed isogenic and non-isogenic cancer cell lines. Correlating with the observed enhanced replication stress we found increased levels of cytosolic double-stranded DNA in KRAS mutant compared to wild-type cells. Yet, despite this phenotype replication stress-inducing agents failed to selectively impact KRAS mutant cells, which were protected by CHK1. Similarly, most exogenous stressors studied did not differentially augment cytosolic DNA accumulation in KRAS mutant compared to wild-type cells. However, we found that proton radiation was able to slow fork progression and preferentially induce fork stalling in KRAS mutant cells. Proton treatment also partly reversed the radioresistance associated with mutant KRAS. The cellular effects of protons in the presence of KRAS mutation clearly contrasted that of other drugs affecting replication, highlighting the unique nature of the underlying DNA damage caused by protons. Taken together, our findings provide insight into the replication stress response associated with mutated KRAS, which may ultimately yield novel therapeutic opportunities.

AB - Mutant KRAS is a common tumor driver and frequently confers resistance to anti-cancer treatments such as radiation. DNA replication stress in these tumors may constitute a therapeutic liability but is poorly understood. Here, using single-molecule DNA fiber analysis, we first characterized baseline replication stress in a panel of unperturbed isogenic and non-isogenic cancer cell lines. Correlating with the observed enhanced replication stress we found increased levels of cytosolic double-stranded DNA in KRAS mutant compared to wild-type cells. Yet, despite this phenotype replication stress-inducing agents failed to selectively impact KRAS mutant cells, which were protected by CHK1. Similarly, most exogenous stressors studied did not differentially augment cytosolic DNA accumulation in KRAS mutant compared to wild-type cells. However, we found that proton radiation was able to slow fork progression and preferentially induce fork stalling in KRAS mutant cells. Proton treatment also partly reversed the radioresistance associated with mutant KRAS. The cellular effects of protons in the presence of KRAS mutation clearly contrasted that of other drugs affecting replication, highlighting the unique nature of the underlying DNA damage caused by protons. Taken together, our findings provide insight into the replication stress response associated with mutated KRAS, which may ultimately yield novel therapeutic opportunities.

KW - Cell Line, Tumor

KW - Cell Proliferation/radiation effects

KW - DNA/genetics

KW - DNA Damage/radiation effects

KW - DNA Replication/genetics

KW - Humans

KW - Mutation/radiation effects

KW - Neoplasms/genetics

KW - Proto-Oncogene Proteins p21(ras)/genetics

KW - Protons/adverse effects

KW - Radiation Tolerance/genetics

KW - Single Molecule Imaging

U2 - 10.1038/s41598-021-83142-y

DO - 10.1038/s41598-021-83142-y

M3 - SCORING: Journal article

C2 - 33574444

VL - 11

JO - SCI REP-UK

JF - SCI REP-UK

SN - 2045-2322

IS - 1

M1 - 3656

ER -