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Single-molecule imaging quantifies oncogenic KRAS dynamics for enhanced accuracy of therapeutic efficacy assessment
Ryoma Yokoi1,2, Toshiki Mori3,4, Koichiro M Hirosawa2
1Department of Gastroenterological Surgery and Pediatric Surgery, Graduate School of Medicine, Gifu University, Gifu 501-1193, Japan.
Abstract:
Oncogenic KRAS mutations are frequent in colorectal cancer, presenting substantial challenges due to constitutive activation and resistance to molecular-targeted therapies driven by mutation-specific biochemical properties. In this study, using single-molecule imaging, we quantitatively analyzed diffusional behaviors of oncogenic KRAS mutants and associated signaling molecules to elucidate their signaling mechanisms and therapeutic implications. Upon EGF stimulation, KRAS molecules exhibited transient trapping and reduced diffusion due to interactions with SOS1 and BRAF, leading to the temporary formation of signaling complexes. Our results demonstrate that analysis of the temporal fraction and frequency of transient trapping events offers a more sensitive and precise evaluation of KRAS activation levels than western blotting. Furthermore, the study of dynamics of individual oncogenic KRAS molecules provides a more accurate assessment of the therapeutic efficacy of various molecular-targeted drugs. Consequently, we propose a highly sensitive strategy to enhance the therapeutic targeting of oncogenic KRAS in living colorectal cancer cells.
Insights
Analyzing KRAS protein dynamics in colorectal cancer using single-molecule imaging reveals new therapeutic targets. This method offers a more sensitive way to evaluate KRAS activation and drug efficacy.
Area of Science:
- Molecular biology
- Cellular signaling
- Cancer research
Background:
- Oncogenic KRAS mutations are prevalent in colorectal cancer.
- These mutations lead to constitutive activation and resistance to targeted therapies.
- Understanding KRAS signaling dynamics is crucial for effective treatment.
Purpose of the Study:
- To quantitatively analyze the diffusional behaviors of oncogenic KRAS mutants.
- To elucidate KRAS signaling mechanisms and therapeutic implications using single-molecule imaging.
- To develop a more sensitive method for evaluating KRAS activation and drug efficacy.
Main Methods:
- Single-molecule imaging techniques were employed.
- Diffusional behaviors of oncogenic KRAS mutants and associated signaling molecules were analyzed.
- Transient trapping and reduced diffusion events were quantified upon EGF stimulation.
Main Results:
- KRAS molecules showed transient trapping and reduced diffusion due to interactions with SOS1 and BRAF.
- Temporary formation of signaling complexes was observed.
- Analysis of transient trapping events proved more sensitive than western blotting for evaluating KRAS activation.
Conclusions:
- Single-molecule dynamics provide a precise assessment of oncogenic KRAS activation.
- This approach offers a more accurate evaluation of molecular-targeted drug efficacy.
- A sensitive strategy is proposed to enhance therapeutic targeting of oncogenic KRAS in colorectal cancer cells.
