Oncogenic mutation or overexpression of oncogenic KRAS or BRAF is not sufficient to confer oncogene addiction

Abstract

Oncogene addiction is a cellular property by which cancer cells become highly dependent on the expression of oncogenes for their survival. Oncogene addiction can be exploited to design molecularly targeted drugs that kill only cancer cells by inhibiting the specific oncogenes. Genes and cell lines exhibiting oncogene addiction, as well as the mechanisms by which cell death is induced when addicted oncogenes are suppressed, have been extensively studied. However, it is still not fully understood how oncogene addiction is acquired in cancer cells. Here, we take a synthetic biology approach to investigate whether oncogenic mutation or oncogene expression suffices to confer the property of oncogene addiction to cancer cells. We employed human mammary epithelium-derived MCF-10A cells expressing the oncogenic KRAS or BRAF. MCF-10A cells harboring an oncogenic mutation in a single-allele of KRAS or BRAF showed weak tumorigenic activity, but no characteristics of oncogene addiction. MCF-10A cells overexpressing oncogenic KRAS demonstrated the tumorigenic activity, but MCF-10A cells overexpressing oncogenic BRAF did not. Neither cell line exhibited any oncogene addiction properties. These results indicate that the introduction of oncogenic mutation or the overexpression of oncogenes is not sufficient for cancer cells to acquire oncogene addiction, and that oncogene addiction is not associated with tumorigenic potential.

Interplay Between KRAS and LZTR1 Protein Turnover, Controlled by CUL3/LZTR1 E3 Ubiquitin Ligase, is Disrupted by KRAS Mutations

“…The use of an isogenic cell line as control reduced interference due to different cellular backgrounds. Our approach relied on an over-expression system, and it is known to potentially provoke cell transformation (Ito et al, 2021). However, we have carefully controlled this with an optimised starvation protocol to mimic a "baseline state".…”