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
4758 - A Phase I Study of the CDK4/6 Inhibitor, Palbociclib in combination with Cetuximab and Intensity Modulated Radiation Therapy (IMRT) for Locally Advanced Squamous Cell Carcinoma of the Head and Neck (SCCHN); A Result of Dose Escalation Cohort
Presenter: Nuttapong Ngamphaiboon
Session: Poster Display session 3
Resources:
Abstract
2607 - Single cycle induction treatment with Cisplatin/Docetaxel plus Durvalumab/Tremelimumab in Stage III-IVB head and neck squamous cell cancer (CheckRad-CD8 trial)
Presenter: Markus Hecht
Session: Poster Display session 3
Resources:
Abstract
1388 - Radiotherapy plus cisplatin (CDDP) or cetuximab (C225) in human papilloma-virus (HPV)-associated oropharyngeal cancer (OPC)? A dillema finally resolved. An updated meta-analysis.
Presenter: Petar Suton
Session: Poster Display session 3
Resources:
Abstract
1478 - Treatment outcomes of head and neck cancer patients 70 years and older receiving different chemo-radiation combinations.
Presenter: Majd Issa
Session: Poster Display session 3
Resources:
Abstract
3985 - Brachytherapy and non-cancer mortality in patients with oral cavity and oropharynx SCCs
Presenter: Jovian Yu
Session: Poster Display session 3
Resources:
Abstract
4036 - Final results of a phase II study of induction chemotherapy (CT) with paclitaxel (PTX) and panitumumab (P) followed by radiotherapy (RT) and P in patients (pts) with locally advanced head and neck cancer (LAHNC) no candidates to platinum: study PANTERA
Presenter: Javier Martinez Trufero
Session: Poster Display session 3
Resources:
Abstract
4779 - Window of Opportunity for Durvalumab (MEDI4736) plus Metformin Trial in Squamous Cell Carcinoma of the Head and Neck (SCCHN): interim safety analysis
Presenter: Tony Richa
Session: Poster Display session 3
Resources:
Abstract
2757 - Severe Oral Mucositis (SOM) Mitigation by Genetically Modified Lactococcus Lactis Bacteria (LLB) Producing Human Trefoil Factor 1 (hTFF1; AG013) in Patients Being Treated With Concomitant Chemoradiation (CRT) for Oral and Oropharyngeal Cancers (OCOPC)
Presenter: Suraj Singh
Session: Poster Display session 3
Resources:
Abstract
5559 - Transcriptome signatures of treatment responses in a preoperative window of opportunity trial of nivolumab and tadalafil in resectable squamous cell carcinoma of the head and neck
Presenter: Sanket Shukla
Session: Poster Display session 3
Resources:
Abstract
3263 - Risk and Impact of Renal Impairment of Locally Advanced Head and Neck Squamous Cell Carcinoma Patients Who Received Chemoradiotherapy with Cisplatin
Presenter: Thana Patimarattananan
Session: Poster Display session 3
Resources:
Abstract