Mouse avatar models of esophageal squamous cell carcinoma proved the potential for EGFR-TKI afatinib and uncovered Src family kinases involved in acquired resistance

Abstract

BackgroundNo approved targeted agents are available for esophageal squamous cell carcinoma (ESCC). Informative genomic analysis and mouse patient-derived xenografts (PDX) also called mouse avatar can greatly expedite drug discovery.MethodsSix ESCC cell lines and 7 out of 25 PDX models derived from 188 biopsies with clear molecular features were employed to evaluate the sensitivity of several EGFR blockers in vitro and in vivo, as well as the underlying antitumor mechanisms of the most promising EGFR-TKI afatinib. Mechanisms involved in acquired resistance of afatinib were explored based on established resistant cell lines and PDX models followed by an attempt to reverse resistance.ResultsCompared with other EGFR blockers, the second-generation EGFR-TKI afatinib exerted superior antitumor effects in ESCC, and EGFR copy number gain (CNG) or overexpression was proposed to be predictive biomarkers. Afatinib played its antitumor effects by inhibiting EGFR downstream pathways, as well as inducing apoptosis and cell cycle arrest at G1. It was increased phosphorylation of Src family kinases (SFKs), rather than MET upregulation, that conferred to acquired resistance of afatinib. Dual blockade of EGFR and SFKs could overcome afatinib resistance and warrants validation in clinical practice.ConclusionBoth ESCC cell lines and PDXs with EGFR CNG or overexpression are potential candidates for afatinib, and concomitant EGFR/SFKs inhibition could reverse afatinib-acquired resistance caused by SFKs activation in ESCC.Electronic supplementary materialThe online version of this article (10.1186/s13045-018-0651-z) contains supplementary material, which is available to authorized users.

EPHA2 blockade reverses acquired resistance to afatinib induced by EPHA2‐mediated MAPK pathway activation in gastric cancer cells and avatar mice

“…Based on the current results, we supposed that the reactivation of PI3K/AKT pathway might also be caused by other upstream molecules. Previous studies have reported that MET and SFKs, conferred EGFR‐TKI resistance by activating PI3K/AKT and MAPK signaling . However, we did not detect abnormal expression of these molecules at transcriptional and protein levels in the present study.…”

“…Previous studies have reported that MET and SFKs, conferred EGFR-TKI resistance by activating PI3K/AKT and MAPK signaling. [36][37][38] However, we did not detect abnormal expression of these molecules at transcriptional and protein levels in the present study. Further attempts need to be made to excavate the potential upstream molecules and elucidate the underlying mechanism in the resistant model.…”

Determining the effects of trastuzumab, cetuximab and afatinib by phosphoprotein, gene expression and phenotypic analysis in gastric cancer cell lines

“…However, it is also possible that the effect on the cell cycle in MKN1 cells is visible only after prolonged afatinib treatment. Afatinib-induced cell cycle arrest was measured by flow cytometry in various cell lines including HNSCC, pancreatic carcinoma, colorectal carcinoma, esophageal squamous carcinoma, gastric carcinoma, ovarian carcinoma and oral squamous carcinoma [ 25 , 28 , 30 , 32 , 45 – 49 ]. In gastric carcinoma cells a sub-G1/G1 cell cycle arrest was detected in NCI-N87 and SNU216 after afatinib treatment, whereas SNU668 cells showed no changes in cell cycle distribution [ 32 ].…”

Pyrotinib combined with CDK4/6 inhibitor in HER2‐positive metastatic gastric cancer: A promising strategy from AVATAR mouse to patients

“…Next‐generation DNA sequencing and transcriptomic sequencing were performed and analyzed by Novogene Bioinformatics Institute (Beijing, China) as previously reported 11 . The correlation coefficient was calculated by the fragments per kilobase million to compare the differences among samples.…”