Novel EPHB4 Receptor Tyrosine Kinase Mutations and Kinomic Pathway Analysis in Lung Cancer

Our plain-English summary of Novel EPHB4 Receptor Tyrosine Kinase Mutations and Kinomic Pathway Analysis in Lung Cancer, by B.D. Ferguson, Y.H. Carol Tan, R.S. Kanteti, et al (Scientific Reports, 2015).

The study

• Authors: B.D. Ferguson, Y.H. Carol Tan, R.S. Kanteti, R. Liu, M.J. Gayed, E.E. Vokes, M.K. Ferguson, A. John Iafrate, P.S. Gill, R. Salgia
• Journal: Scientific Reports
• Published: 2015;5:10641
• Cited by: 22 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Lung cancer outcomes remain poor despite the identification of several potential therapeutic targets. The EPHB4 receptor tyrosine kinase (RTK) has recently emerged as an oncogenic factor in many cancers, including lung cancer. Mutations of EPHB4 in lung cancers have previously been identified, though their significance remains unknown. Here, we report the identification of novel EPHB4 mutations that lead to putative structural alterations as well as increased cellular proliferation and motility. We also conducted a bioinformatic analysis of these mutations to demonstrate that they are mutually exclusive from other common RTK variants in lung cancer, that they correspond to analogous sites of other RTKs' variations in cancers, and that they are predicted to be oncogenic based on biochemical, evolutionary, and domain-function constraints. Finally, we show that EPHB4 mutations can induce broad changes in the kinome signature of lung cancer cells. Taken together, these data illuminate the role of EPHB4 in lung cancer and further identify EPHB4 as a potentially important therapeutic target.

In plain English

This laboratory study searched for changes (mutations) in a gene called EPHB4 in tumor tissue from the University of Chicago Tumor Tissue Bank. The samples were 32 lung adenocarcinoma, 46 small cell lung cancer, 32 squamous cell lung carcinoma, 22 head and neck squamous cell carcinoma and 32 pleural mesothelioma tissues, plus a panel of cell lines. The article does not mention asbestos or any patient's exposure history. The authors found eight protein-changing EPHB4 mutations in lung cancer tissues, seven of them not reported before. They found none in the cell lines, the head and neck tissues or the pleural mesothelioma tissues. In lung cancer cells grown in the laboratory, three mutant forms (G723S, A742V and P881S) increased cell growth by 30%, 36% and 45% respectively after 48 hours, compared with cells given transfection reagent only. Without ephrin-B2 stimulation, cells with the A742V form moved more than cells with normal EPHB4. The authors concluded that EPHB4 is a potentially important treatment target and that these mutations may act as "driver" mutations. They noted that each mutation appeared in only one sample and that the experiments used cultured cells.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory study: gene sequencing of stored tumor tissues and cell lines, computer (bioinformatic) predictions, and cell-culture experiments with mutant EPHB4
• Who was studied: Tumor tissues from the University of Chicago Tumor Tissue Bank: 32 lung adenocarcinoma, 46 small cell lung cancer, 32 squamous cell lung carcinoma, 22 squamous cell carcinoma of the head and neck, and 32 pleural mesothelioma tissues, plus a panel of lung and non-lung cell lines. Dates of collection are not given.
• Exposure: No asbestos or other environmental or occupational exposure was studied. In the experiments, laboratory cells were given normal (wild-type) EPHB4 or one of three mutant forms (G723S, A742V, P881S).
• Main results:
  • Eight non-synonymous (protein-changing) EPHB4 mutations were found in lung cancer tissues: three in adenocarcinoma, one in squamous cell carcinoma and four in small cell lung cancer.
  • Seven of the eight mutations had not been detected before.
  • No non-synonymous EPHB4 mutations were found in the head and neck squamous cell carcinoma tissues or the pleural mesothelioma tissues.
  • No non-synonymous mutations were found in the cell lines.
  • The authors reported non-synonymous mutations in 7% of samples overall: 9% in adenocarcinoma, 9% in small cell lung cancer and 3% in squamous cell carcinoma.
  • Three of the eight mutations were predicted by the CanPredict software to be associated with cancer.
  • Of the six tissues carrying EPHB4 mutations, two had no other mutations at the sites checked in other cancer genes, and each of the other four had one other mutation.
  • In H661 lung cancer cells, normal EPHB4 increased cell growth by 16% at 24 hours, falling to 9% the next day. After 48 hours, the G723S, A742V and P881S mutants increased growth by 30%, 36% and 45% respectively, compared with mock-transfected cells.
  • Without ephrin-B2 stimulation, H661 cells with the A742V mutation moved more and closed scratch wounds to a greater extent than cells with normal (wild-type) EPHB4.
  • Phosphorylation of the A742V and P881S mutant proteins was sharply reduced compared with normal EPHB4.
  • The mutants increased phosphorylation of several other signaling proteins, including CDK2, EPHA2, EpoR and VEGFR2.
• The authors' conclusion: The authors concluded that the data shed light on the role of EPHB4 in lung cancer and identify it as a potentially important treatment target. They also suggested that the mutations may act as driver mutations.
• Limitations the authors state:
  • Each mutation was found in only one sample, so the authors said the mutations should be treated as isolated events until they are found in more patients.
  • Whether the mutations were inherited (germline) or arose in the tumor (somatic) was not known.
  • The status of a number of gene sites in the other cancer genes was not determined, which the authors said makes a definitive conclusion more difficult.
  • The kinase assays measured only tyrosine phosphorylation, not serine or threonine phosphorylation.
  • The findings come from cultured cells; studies in living organisms are still needed.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Lung Cancer.

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• Identification of a novel EphB4 phosphodegron regulated by the autocrine IGFII/IRA axis in malignant mesothelioma — P. Scalia, G. Pandini, et al. (2019)
• Coactivation of receptor tyrosine kinases in malignant mesothelioma as a rationale for combination targeted therapy — M. Brevet, S. Shimizu, et al. (2011)
• EphB4 as a therapeutic target in mesothelioma — R. Liu, B.D. Ferguson, et al. (2013)
• Case report: targeted therapy of malignant pleural mesothelioma with anaplastic lymphoma kinase receptor tyrosine kinase gene fusion mutation by crizotinib — Y. Wu, Y. Zhao, et al. (2024)
• Patients with peritoneal mesothelioma lack epidermal growth factor receptor tyrosine kinase mutations that would make them sensitive to tyrosine kinase inhibitors — N. Kalra, A. Ashai, et al. (2012)

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