Abstract 767
Background
HRAS is mutated or overexpressed in various cancers. Although numerous studies have demonstrated that HRAS mutations (HRASmut) promote chemoresistance in HNSCC, the effect of wild type HRAS overexpression (wtHRASov) on chemotherapy has not yet been studied. We sought: i. to investigate the repair capacity of wtHRASov tumors in cisplatin- induced damage and ii. to explore the cisplatin sensitizing effect of HRAS inhibitor tipifarnib.
Methods
Mutation/RNA and cisplatin IC50 data were retrieved from the Cancer Genome Atlas (TCGA) and COSMIC Cell Lines Project respectively. Modified Z-score was used to define HRAS overexpression. Patient derived xenografts (PDXs) were generated from treatment naïve HNSCC patients. Mutational and expression profile of tumor grafts was identified by whole exome sequencing, IHC, qRT-PCR and western blot analysis. Cisplatin or cisplatin combined with tipifarnib was used for PDX’s treatment. Therapy response was monitored by sequential tumor volume measurements over time.
Results
Our analysis of available RNA and cisplatin IC50 data from HNSCC cell lines demonstrated that wild type HRAS levels are positively correlated with cisplatin resistance. To identify resistance signatures in wtHRASov tumors, we compared the TCGA HNSCC transcriptomes of HRAS-altered (HRASmut or wtHRASov) and HRAS- unaltered tumors. Approximately 6% of HNSCCs were overexpressing HRAS, and there was only partial overlap with the 6% of HRASmut tumors. Moreover, ERCC1 was found highly upregulated in HRAS altered group and especially among wtHRASov subcluster. To further study the resistance of wtHRASov tumors, we generated a cohort of HNSCC PDXs and acquired their mutational, expression and chemosensitivity profile. PDX tumors harboring a profile similar to wtHRASov TCGA cluster exhibited a strong chemoresistant squamous phenotype associated with high ERCC1 levels. Interestingly, these tumors were resensitized to cisplatin when subjected to cisplatin/tipifarnib combinatorial treatment.
Conclusions
ERCC1 expression is a well-established biomarker for cisplatin resistance. Our study demonstrates that wtHRASov tumours represent a distinctive entity that strongly express ERCC1 and can be resensitized to cisplatin by tipifarnib.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Kura Oncology.
Disclosure
T. Rampias: Research grant / Funding (institution): Kura Oncology Company. All other authors have declared no conflicts of interest.
Resources from the same session
2344 - Lung Cancer in Europe: strengthening policy responses to address unmet needs
Presenter: Mary Bussell
Session: Poster Display session 3
Resources:
Abstract
1359 - Curative treatment timelines for breast, colorectal, lung and prostate cancer: Implications for medical leave coverage
Presenter: Selina Wong
Session: Poster Display session 3
Resources:
Abstract
4433 - Acute Diagnostic Oncology Clinic: A Unique Primary Care-Oncology Service
Presenter: Abhijit Gill
Session: Poster Display session 3
Resources:
Abstract
3506 - THE NEW MUTATIONAL MODEL IN ONCOLOGY. What changes in welfare, clinical practice, research, and regulatory procedures
Presenter: Nicola Normanno
Session: Poster Display session 3
Resources:
Abstract
3350 - Selection of a set of quality indicators (QI) for oncological clinical pathway
Presenter: Aude Fourcade
Session: Poster Display session 3
Resources:
Abstract
4400 - Sustainable drug prices at market launch: policy proposals and their empirical evidence
Presenter: Nora Fanzen
Session: Poster Display session 3
Resources:
Abstract
4118 - Impact of financial considerations on French physicians’ prescription choices for advanced non-small cell lung cancer (NSCLC)
Presenter: Nathalie Olympios
Session: Poster Display session 3
Resources:
Abstract
1340 - The direct medical cost of breast cancer in a Belgian hospital
Presenter: Hannan Lemhouer
Session: Poster Display session 3
Resources:
Abstract
1863 - Does the healthcare system approaches cancer patients for using private services during diagnostic process?
Presenter: Karolina Osowiecka
Session: Poster Display session 3
Resources:
Abstract
2637 - Measuring financial toxicity of cancer in the Italian health care system: initial results of the patient reported outcome for Fighting Financial Toxicity of cancer project (proFFiT).
Presenter: Silvia Riva
Session: Poster Display session 3
Resources:
Abstract