Supplemental Figures 1-7 and Legends from Downregulating Neuropilin-2 Triggers a Novel Mechanism Enabling EGFR-Dependent Resistance to Oncogene-Targeted Therapies
Suppl. Figures 1 and 2 show supporting evidence concerning the role of Nrp2 in non oncogene-addicted carcinoma cells A549 and PC3, and EGFR-addicted cancer cells PC9. Suppl. Fig. 3 shows supporting information concerning the role of Nrp2 and its splice isoforms in Met-addicted cells. Suppl. Fig. 4 contains supporting evidence about concomitant Nrp2 and EGFR regulation in addicted cells which developed resistance to targeted therapy. Suppl. Fig. 5 contains supporting evidence about EGFR endocytosis and protein stability in targeted-therapy-resistant cells, as well as KIAA1199 knock-down validation data in the same cells. Suppl. Fig. 6 shows supporting evidence about IKB regulation by Nrp2, as well as validation data on KIAA1199 gene silencing in different cancer cells. Suppl. Fig. 7 describes the impact of Nrp2-silencing in multiple melanoma cells, as well as in mesenchymal-type MDAMB231 carcinoma cells.
Funding
AIRC
FPRC
Fondazione Veronesi
Italian Association for Cancer Research
Fondazione Piemontese per la Ricerca sul Cancro - ONLUS
FPRC-ONLUS
History
ARTICLE ABSTRACT
Neuropilins are a class of cell surface proteins implicated in cell migration and angiogenesis, with aberrant expression in human tumors. Here, we show that the expression of Neuropilin-2 (NRP2) controls EGFR protein levels, thereby impinging on intracellular signaling, viability, and response to targeted therapies of oncogene-addicted cells. Notably, increased NRP2 expression in EGFR-addicted tumor cells led to downregulation of EGFR protein and tumor cell growth inhibition. NRP2 also blunted upregulation of an EGFR "rescue" pathway induced by targeted therapy in Met-addicted carcinoma cells. Cancer cells acquiring resistance to MET oncogene-targeted drugs invariably underwent NRP2 loss, a step required for EGFR upregulation. Mechanistic investigations revealed that NRP2 loss activated NFkB and upregulated the EGFR-associated protein KIAA1199/CEMIP, which is known to oppose the degradation of activated EGFR kinase. Notably, KIAA1199 silencing in oncogene-addicted tumor cells improved therapeutic responses and counteracted acquired drug resistance. Our findings define NRP2 as the pivotal switch of a novel broad-acting and actionable pathway controlling EGFR signaling, and driving resistance to therapies targeting oncogene-addiction.Significance: These important findings identify the cell surface molecule Nrp2 as the pivotal switch of a novel, actionable pathway driving EGFR upregulation and resistance to oncogene- targeted therapies. Cancer Res; 78(4); 1058–68. ©2017 AACR.Usage metrics
