The Src inhibitor peptide TAT-Cx43266-283 improves survival in an intracranial murine model of lung cancer brain metastasis

Abstract Background TAT-Cx43266-283 is a novel Src inhibitor, which has shown noteworthy antitumor effects in preclinical models of glioblastoma. Because Src plays a pivotal role in several tumor types, including lung cancer brain metastasis derived from non-small cell lung cancer (NSCLC) cells, we investigated the effect of TAT-Cx43266-283 in NSCLC-derived brain metastasis, a disease of unmet clinical need. Methods The effect of TAT-Cx43266-283 was studied in Lewis Lung Carcinoma (LLC), LSZ4, A549, and H441 NSCLC cells. The non-adherent stem-like LLC cells (LLC-CSCs) were intracranially implanted in immunocompetent mice to study the effect of TAT-Cx43266-283 in vivo. Phosphoproteomic analysis was employed to identify signaling pathways affected by TAT-Cx43266-283, and the most prominent were validated by Western blot and immunohistochemistry. Datasets of human NSCLC adenocarcinoma were also analyzed. Results TAT-Cx43266-283 significantly reduced LLC-CSCs viability and increased the survival of mice bearing brain tumors derived from these cells. Phosphoproteomic analysis identified MEK and ERK as key effectors of this treatment. TAT-Cx43266-283 induced apoptosis, impaired cytoskeletal dynamics and disrupted tumor vascularization. Patient datasets revealed that the targets of TAT-Cx43266-283 were significantly enriched in KRAS-altered lung tumors. Functional validation in several human and mouse KRAS-mutated non-adherent NSCLC cells confirmed that TAT-Cx43266-283 reduced their growth and invasiveness. Conclusions Our results suggest that TAT-Cx43266-283 is a promising antitumor drug for lung cancer brain metastasis, as judged by the dual inhibition of Src and the MEK-ERK pathway in KRAS-mutated NSCLC. This study opens new avenues for exploring TAT-Cx43266-283 in other tumor types driven by these molecular alterations.