Anti-BRAF monoclonal antibody, clone 2G23G22D0

Carcinoma development in colorectal cancer is driven by genetic alterations in numerous signaling pathways. Alterations in the RAS-ERK1/2 pathway are associated with the shortest overall survival for patients after diagnosis of colorectal cancer metastatic disease, yet how RAS-ERK signaling regulates colorectal cancer metastasis remains unknown. In this study, we used an unbiased screening approach based on selection of highly liver metastatic colorectal cancer cells in vivo to determine genes associated with metastasis. From this, an ERK1/2-controlled metastatic gene set (EMGS) was defined. EMGS was associated with increased recurrence and reduced survival in patients with colorectal cancer tumors. Higher levels of EMGS expression were detected in the colorectal cancer subsets consensus molecular subtype (CMS)1 and CMS4. ANGPT2 and CXCR4, two genes within the EMGS, were subjected to gain-of-function and loss-of-function studies in several colorectal cancer cell lines and then tested in clinical samples. The RAS-ERK1/2 axis controlled expression of the cytokine ANGPT2 and the cytokine receptor CXCR4 in colorectal cancer cells, which facilitated development of liver but not lung metastases, suggesting that ANGPT2 and CXCR4 are important for metastatic outgrowth in the liver. CXCR4 controlled the expression of cytokines IL10 and CXCL1, providing evidence for a causal role of IL10 in supporting liver colonization. In summary, these studies demonstrate that amplification of ERK1/2 signaling in KRAS-mutated colorectal cancer cells affects the cytokine milieu of the tumors, possibly affecting tumor-stroma interactions and favoring liver metastasis formation. Significance: These findings identify amplified ERK1/2 signaling in KRAS-mutated colorectal cancer cells as a driver of tumorstroma interactions that favor formation of metastases in the liver.

Background: Several mechanisms likely cooperate with the mitogen-activated protein (MAP)-kinase pathway to promote cancer progression in the thyroid. One putative pathway is NOTCH signaling, which is implicated in several other malignancies. In thyroid cancer, data regarding the role of the NOTCH pathway are insufficient and even contradictory. Methods: A BRAF(V600E)-driven papillary thyroid carcinoma (PTC) mouse model was subjected to NOTCH pathway genetic alterations, and the tumor burden was followed by ultrasound. Further analyses were performed on PTC cell lines or noncancerous cells transfected with NOTCHIC or BRAF(V600E), which were then subjected to pharmacological treatment with MAP-kinase or NOTCH pathway inhibitors. Results: The presence of the BRAF(V600E) mutation coupled with overexpression of the NOTCH intracellular domain led to significantly bigger thyroid tumors in mice, to a more aggressive carcinoma, and decreased overall survival. Although more cystic, the tumors did not progress into anaplastic thyroid carcinomas. On the contrary, the deletion of RBP-j kappa (a major cofactor involved in NOTCH signaling) did not alter the phenotype in mice. BRAF(V600E)-mutated PTC cell lines were resistant to pharmacological inhibition of the NOTCH pathway. Inhibition of MEK1/2 uncovered a predominant effect on Hes1/Hey1 transcription compared with NOTCH inhibition in BRAF(V600E)-mutated cell lines. Finally, gamma-secretase activity and gamma-secretase subunit transcription levels were dependent on ERK activation. Our findings suggest that MAP-kinase activity overrides the NOTCH pathway in the context of thyroid cancer. Conclusions: The interaction between the BRAF and NOTCH pathways demonstrates that the BRAF(V600E) mutation might bypass NOTCH and exert a strong positive effect on NOTCH downstream targets in thyroid carcinoma.