American Association for Cancer Research
00085472can130681-sup-figure_4.pdf (1.01 MB)

Supplementary Figure 4 from Mutationally Activated PIK3CAH1047R Cooperates with BRAFV600E to Promote Lung Cancer Progression

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journal contribution
posted on 2023-03-30, 21:53 authored by Christy L. Trejo, Shon Green, Victoria Marsh, Eric A. Collisson, Gioia Iezza, Wayne A. Phillips, Martin McMahon

PDF file, 1038K, Ad-SPC-Cre initiation of BRafCA; Pik3calat mice leads to malignant lung cancer.



Adenocarcinoma of the lung, a leading cause of cancer death, frequently displays mutational activation of the KRAS proto-oncogene but, unlike lung cancers expressing mutated EGFR, ROS1, or ALK, there is no pathway-targeted therapy for patients with KRAS-mutated lung cancer. In preclinical models, expression of oncogenic KRASG12D in the lung epithelium of adult mice initiates development of lung adenocarcinoma through activation of downstream signaling pathways. In contrast, mutationally activated BRAFV600E, a KRAS effector, fails to initiate lung carcinogenesis despite highly efficient induction of benign lung tumorigenesis. To test if phosphoinositide 3-kinase (PI3K)-α (PIK3CA), another KRAS effector, might cooperate with oncogenic BRAFV600E to promote lung cancer progression, we used mice carrying a conditional allele of Pik3ca that allows conversion of the wild-type catalytic subunit of PIK3CA to mutationally activated PIK3CAH1047R. Although expression of PIK3CAH1047R in the lung epithelium, either alone or in combination with PTEN silencing, was without phenotype, concomitant expression of BRAFV600E and PIK3CAH1047R led to dramatically decreased tumor latency and increased tumor burden compared with BRAFV600E alone. Most notably, coexpression of BRAFV600E and PIK3CAH1047R elicited lung adenocarcinomas in a manner reminiscent of the effects of KRASG12D. These data emphasize a role for PI3K signaling, not in lung tumor initiation per se, but in both the rate of tumor growth and the propensity of benign lung tumors to progress to a malignant phenotype. Finally, biologic and biochemical analysis of BRAFV600E/PIK3CAH1047R-expressing mouse lung cancer cells revealed mechanistic clues about cooperative regulation of the cell-division cycle and apoptosis by these oncogenes. Cancer Res; 73(21); 6448–61. ©2013 AACR.