RET/PTC-induced cell growth is mediated in part by epidermal growth factor receptor (EGFR) activation: evidence for molecular and functional interactions between RET and EGFR

RET/PTC rearrangements are one of the genetic hallmarks of papillary thyroid carcinomas. RET/PTC oncoproteins lack extracellular or transmembrane domains, and activation takes place through constitutive dimerization mediated through coiled-coil motifs in the NH(2) terminus of the chimeric protein. Based on the observation that the epidermal growth factor receptor (EGFR) kinase inhibitor PKI166 decreased RET/PTC kinase autophosphorylation and activation of downstream effectors in thyroid cells, despite lacking activity on the purified RET kinase, we proceeded to examine possible functional interactions between RET/PTC and EGFR. Conditional activation of RET/PTC oncoproteins in thyroid PCCL3 cells markedly induced expression and phosphorylation of EGFR, which was mediated in part through mitogen-activated protein kinase signaling. RET and EGFR were found to coimmunoprecipitate. The ability of RET to form a complex with EGFR was not dependent on recruitment of Shc or on their respective kinase activities. Ligand-induced activation of EGFR resulted in phosphorylation of a kinase-dead RET, an effect that was entirely blocked by PKI166. These effects were biologically relevant, as the EGFR kinase inhibitors PKI166, gefitinib, and AEE788 inhibited cell growth induced by various constitutively active mutants of RET in thyroid cancer cells as well as NIH3T3 cells. These data indicate that EGFR contributes to RET kinase activation, signaling, and growth stimulation and may therefore be an attractive therapeutic target in RET-induced neoplasms

The Special Pathogens Research Network: Enabling Research Readiness.

The 2013-2016 epidemic of Ebola virus disease (EVD) that originated in West Africa underscored many of the challenges to conducting clinical research during an ongoing infectious disease epidemic, both in the most affected countries of Guinea, Liberia, and Sierra Leone, as well as in the United States and Europe, where a total of 27 patients with EVD received care in biocontainment units. The Special Pathogens Research Network (SPRN) was established in the United States in November 2016 to provide an organizational structure to leverage the expertise of the 10 Regional Ebola and Other Special Pathogen Treatment Centers (RESPTCs); it was intended to develop and support infrastructure to improve readiness to conduct clinical research in the United States. The network enables the rapid activation and coordination of clinical research in the event of an epidemic and facilitates opportunities for multicenter research when the RESPTCs are actively caring for patients requiring a biocontainment unit. Here we provide an overview of opportunities identified in the clinical research infrastructure during the West Africa EVD epidemic and the SPRN activities to meet the ongoing challenges in the context of Ebola virus and other special pathogens