Autophosphorylation of the carboxyl‐terminal domain is not required for oncogenic transformation by lung‐cancer derived EGFR mutants

Aberrant activation of cancer‐derived mutants of the epidermal growth factor receptor (EGFR) is closely associated with cancer pathogenesis and is thought to be mediated through multiple tyrosine phosphorylations within the C‐terminal domain. Here, we examined the consequences of the loss of these C‐terminal phosphorylation sites on cellular transformation in the context of lung‐cancer‐derived L858R, exon 19 deletion and exon 20 insertion mutant EGFR. Oncogenic EGFR mutants with substitution of the 10 potential C‐terminal tyrosine autophosphorylation sites for phenylalanine (CYF10) were still able to promote anchorage‐independent growth in soft agar at levels comparable to the parental L858R or exon19 deletion or exon 20 insertion mutants with intact autophosphorylation sites. Furthermore, these CYF10 mutants retained the ability to transform Ba/F3 cells in the absence of IL‐3. Bead‐based phosphorylation and immunoprecipitation analyses demonstrated that key EGFR‐associated proteins—including Grb2 and PLC‐γ—are neither phosphorylated nor bound to CYF10 mutants in transformed cells. Taken together, we conclude that tyrosine phosphorylation is not required for oncogenic activity of lung‐cancer‐derived mutant EGFR, suggesting these mutants can lead to cellular transformation by an alternative mechanism independent of EGFR phosphorylation.     

Continued uncertainty regarding treatment of patent ductus arteriosus in premature infants and the role of clinical trials

Despite several decades of research into treatments for patent ductus arteriosus (PDA), there is continued uncertainty regarding whether, when, and how best to treat PDA and the long-term consequences. There are almost 5000 babies enrolled into clinical trials, but the questions remain largely unanswered. Many of the trials performed over the period were well designed and addressed important clinical questions, but the results are not necessarily directly applicable to the clinical management dilemmas of today since perinatal care has improved over time per se, the patient population is typically more premature, and there have been technological advances in diagnosis. This article examines some of the approaches taken, how trial designs evolved over time, especially in terms of the patient population and outcomes evaluated, and it offers points to consider when planning future research.