Src inhibitors act through different mechanisms in Non-Small Cell Lung Cancer models depending on EGFR and RAS mutational status

Abstract

Resistance to the EGFR tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib, often related to Ras or secondary EGFR mutations, is a relevant clinical issue in NonSmall Cell Lung Cancer (NSCLC). Although Src TK has been involved in such resistance, clinical development of its inhibitors has been so far limited.To better define the molecular targets of the Src TKIs saracatinib, dasatinib and bosutinib, we used a variety of in vitro/in vivo studies.Kinase assays supported by docking analysis demonstrated that all the compounds directly inhibit EGFR TK variants. However, in live cells only saracatinib efficiently reduced EGFR activation, while dasatinib was the most effective agent in inhibiting Src TK. Consistently, a pronounced anti-proliferative effect was achieved with saracatinib, in EGFR mutant cells, or with dasatinib, in wt EGFR/Ras mutant cells, poorly dependent on EGFR and erlotinib-resistant. We then identified the most effective drug combinations to overcome resistance to EGFR inhibitors, both in vitro and in nude mice: in T790M EGFR erlotinib-resistant cells, saracatinib with the anti-EGFR mAb cetuximab; in Ras mutant erlotinib-resistant models, dasatinib with the MEK inhibitor selumetinib. Src inhibitors may act with different mechanisms in NSCLCs, depending on EGFR/Ras mutational profile, and may be integrated with EGFR or MEK inhibitors for different cohorts of NSCLCs.

Large-scale integration of heterogeneous pharmacogenomic data for identifying drug mechanism of action

“…Among these, EGFR, a significantly mutated gene in lung adenocarcinoma, was predicted by Mania as the top 1 gene that can be targeted by the drug Saracatinib but has not been predicted by DNF in its top 10 list. Our prediction of the use of Saracatinib to treat lung cancer through reducing the activation of EGFR is also supported by studies in the literature, 29 where Saracatinib was found to be able to efficiently reduce the activation of EGFR. Interestingly, Saracatinib was clustered into Cluster 16, which contains several well-known EGFR inhibitors, including two launched drugs, Afatinib and Erlotinib.…”

A live-cell screen for altered Erk dynamics reveals principles of proliferative control

“…This analysis was immediately useful in the case of Class 1 inhibitors, which was highly enriched for drugs with activity against EGFR-family (ErbB) receptors and the Erk-activating kinase MEK ( Figure 3E; Table S1). Moreover, even Class 1 drugs that were not annotated as EGFR/MEK inhibitors (e.g., saracatinib, TWS119, ZM306416) have been implicated as direct inhibitors of these nodes in prior studies (Anastassiadis et al, 2011;Antczak et al, 2012;Formisano et al, 2015). Our drug screen thus correctly identified EGFR/MAPK pathway inhibitors as suppressors of dynamic Erk activity in keratinocytes.…”

miR-26a desensitizes non-small cell lung cancer cells to tyrosine kinase inhibitors by targeting PTPN13

“…Src can transactivate EGFR by phosphorylating tyrosine 845 (Y845), which may eventually induce EGFR receptor full activation [57]. Based on this molecular mechanism, TKIs targeting Src family kinases such as saracatinib and dasatinib have been used as therapeutic drugs for NSCLC [58]. We found here that PTPN13 silencing by miR-26a facilitated the activation of Src, therefore, it is likely that sustained Src activation compensates for the kinase activity of EGFR inhibited by EGFR-TKIs.…”