Abstract 3264
Background
A subgroup of MEK1 mutations in human tumors were recently described as RAF- and phosphorylation independent and as insensitive to currently clinically used allosteric MEK inhibitors. We established a novel cell line that carries a MEK1 mutation of this class (pGlu102_Lys104delinsGln) and tested a novel ATP competitive MEK inhibitor (MAP855) in this model. According to our knowledge this is the first patient derived cell line with this type of MEK mutation and the first spitzoid melanoma cell model.
Methods
PF130 cell line was established from the pleural effusion sample of a 37-year-old male patient with spitzoid melanoma. NGS was used for mutational analysis. Cells were treated either with allosteric MEK inhibitor selumetinib or with newly developed ATP competitive MEK inhibitor MAP855. We analyzed changes in cell number, cell cycle distribution and ERK activation after treatment in vitro. Furthermore, the in vivo tumorigenicity was tested by injecting the cells subcutaneously, intrapleurally or intravenously into female SCID mice.
Results
We found that ATP competitive MEK inhibitor MAP855 strongly decreased the viability of PF130 cells, while allosteric inhibitor selumetinib did not. Cell cycle analysis showed that MAP588 treatment could induce cell death in PF130 cells in a concentration dependent manner and slightly reduced the amount of cells in the S and the G2M phases. Furthermore, MAP855 was able to reduce ERK protein activation in PF130 cells effectively while selumetinib treatment had no effect. In vivo, intrapleurally injected cells established macroscopic tumors in the chest cavity after two months while intravenously and subcutaneously delivered cells showed limited growth.
Conclusions
We established a new cellular model of tumors with RAF- and phosphorylation independent MEK mutation. We found that recently developed ATP-competitive MEK inhibitor MAP855 is a potent inhibitor of these cells in vitro. The in vivo efficacy is currently under investigation. Furthermore, we describe here to the best of our knowledge the first patient derived spitzoid melanoma cell model to test both in vitro and in vivo novel therapeutic modalities.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Balazs Hegedus.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
4543 - Long-term real-world (RW) outcomes in patients with advanced melanoma (MEL) treated with ipilimumab (IPI) and non-IPI therapies: IMAGE study
Presenter: Stéphane Dalle
Session: Poster Display session 3
Resources:
Abstract
4523 - Prognostic Factors for efficacy of Ipilimumab used after AntiPD1 and/or BRAF+MEK inhibitors in Melanoma Patients: an Italian Melanoma Intergroup study
Presenter: Riccardo Marconcini
Session: Poster Display session 3
Resources:
Abstract
3632 - Rechallenge with combination ipilimumab and anti-PD-1 (IPI+PD1) in metastatic melanoma after acquired resistance to IPI+PD1 immunotherapy
Presenter: Adriana Hepner
Session: Poster Display session 3
Resources:
Abstract
3732 - Clinicopathologic characteristics of immune colitis in melanoma patients treated with combination ipilimumab and anti-PD1 (IPI+PD1) and PD1 monotherapy.
Presenter: Kazi Nahar
Session: Poster Display session 3
Resources:
Abstract
5005 - Real-world outcomes of ipilimumab plus nivolumab for advanced melanoma in the Netherlands
Presenter: Michiel van Zeijl
Session: Poster Display session 3
Resources:
Abstract
5524 - Utilization of Real-World Data to Assess the Effectiveness of Immune Checkpoint Inhibitors (ICIs) in Elderly Patients with Metastatic Melanoma
Presenter: D Scott Ernst
Session: Poster Display session 3
Resources:
Abstract
5884 - Tumor mutational burden and response to PD-1 inhibitors: an analysis of 89 cases of metastatic melanoma.
Presenter: Léa Dousset
Session: Poster Display session 3
Resources:
Abstract
3120 - Increase in S100B and LDH as early outcome predictors for non-responsiveness to anti-PD-1 monotherapy in advanced melanoma.
Presenter: Elisa Rozeman
Session: Poster Display session 3
Resources:
Abstract
2157 - Immune status defined by molecular information layers predicts response to pembrolizumab treatment in advanced melanoma
Presenter: Guillermo Prado-Vázquez
Session: Poster Display session 3
Resources:
Abstract
2553 - Interim analysis of a phase Ib study of cobimetinib plus atezolizumab in patients with advanced BRAFV600 wild type melanoma progressing on prior anti-PD-L1 therapy
Presenter: Shahneen Sandhu
Session: Poster Display session 3
Resources:
Abstract