Abstract 5739
Background
Mutation of either the intracellular catalytic domain or the extracellular domain of the receptor for epidermal growth factor (EGFR) drives oncogenicity. Extracellular domain EGFR mutations are highly expressed in patients with glioblastoma. Despite clinical success with targeting EGFR catalytic site mutants, no drugs have proven effective in glioblastoma patients expressing extracellular EGFR mutations.
Methods
Herein, we define the molecular mechanism for oncogenic activation of families of extracellular EGFR mutations and reveal how this mechanism renders current generation small molecule ATP-site inhibitors ineffective. We define these types of lesions as allosteric oncogenic mutations.
Results
We demonstrate that a group of the most commonly expressed extracellular domain EGFR mutants expressed in glioblastomas is activated by disulfide-bond mediated covalent homodimerization, collectively referred to as locked dimerization (LoDi-EGFR oncogenes). Strikingly, current generation small molecules binding to the active kinase conformation potently inhibit catalytic site mutants, but induce covalent dimerization and activate LoDi-EGFR receptors, manifesting in paradoxical acceleration of proliferation. Herein we describe the discovery of novel ATP competitive small molecules that potently (<50nM) inhibit the family of LoDi-EGFR oncogenes expressed in GBM, and importantly, achieve selectivity versus WT-EGFR of greater than 10-fold.
Conclusions
These data demonstrate how the locked-dimer mechanism of EGFR oncogenesis has profound impact on the activity of small molecules acting at the distal catalytic site, providing further evidence for “inside-out” allosteric signaling in EGFR. This provides a mechanistic understanding for the failure of current generation EGFR inhibitors to effectively treat LoDi-EGFR mutants in GBM and sets guidelines for the discovery and development of novel selective LoDi-EGFR inhibitors.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Black Diamond Therapeutics.
Funding
Black Diamond Therapeutics.
Disclosure
E. Buck: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment: Black Diamond Therapeutics. M. O’Connor: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment: Black Diamond Therapeutics. A. Flohr: Leadership role, Shareholder / Stockholder / Stock options: Black Diamond Therapeutics. R. Iacone: Leadership role, Shareholder / Stockholder / Stock options: Black Diamond Therapeutics. A.V. Mayweg: Leadership role, Shareholder / Stockholder / Stock options, Officer / Board of Directors: Black Diamond Therapeutics. D.M. Epstein: Leadership role, Shareholder / Stockholder / Stock options, Officer / Board of Directors: Black Diamond Therapeutics. All other authors have declared no conflicts of interest.
Resources from the same session
5519 - Is there a difference of Palliative care problems and needs between cancer and non-cancer hospitalized elderly patients?
Presenter: Ioanna Chatzi
Session: Poster Display session 1
Resources:
Abstract
2505 - There is a lack of clinical research for patients with cancer in palliative care
Presenter: Marie Vinches
Session: Poster Display session 1
Resources:
Abstract
5273 - Specialist Palliative Care (SPC) in Haematological Malignancy: Establishing practices in a UK Tertiary Cancer Centre (TCC)
Presenter: Emma Kedgley
Session: Poster Display session 1
Resources:
Abstract
5864 - Evaluation of the relationship between the attachment styles and psychological resilience of cancer patients receiving chemotherapy
Presenter: Fatma Bugdayci Basal
Session: Poster Display session 1
Resources:
Abstract
770 - Gefitinib along with Methotrexate as palliative therapy in PS 3 and above in metastatic squamous cell carcinoma head and neck cancer patients
Presenter: Vidya Dusi
Session: Poster Display session 1
Resources:
Abstract
4232 - High intensity end-of-life care in pediatrics, adolescent and young adult patients with cancer using an administrative database.
Presenter: Seiko Bun
Session: Poster Display session 1
Resources:
Abstract
4845 - Embedded outpatient palliative care service within the oncology clinic: Preliminary experience in Hacettepe Oncology Hospital
Presenter: Deniz Can Guven
Session: Poster Display session 1
Resources:
Abstract
3270 - Internet-based stepped care for individuals with cancer and concurrent anxiety or depression symptoms – results from a randomized controlled trial
Presenter: Birgitta Johansson
Session: Poster Display session 1
Resources:
Abstract
5503 - Impact of Cognitive-Behavioral-Therapy (CBT) on levels of anxiety, depression and distress in cancer patients (pts)
Presenter: Daniela Tregnago
Session: Poster Display session 1
Resources:
Abstract
5553 - Cytokine genetic variations and worse quality of life among family caregivers of head and neck cancer patients in palliative care
Presenter: Daniel Pequeno
Session: Poster Display session 1
Resources:
Abstract