A patient-derived somatic mutation in the epidermal growth factor receptor ligand-binding domain confers increased sensitivity to cetuximab in head and neck cancer

PI3K pathway mutation predicts an activated immune microenvironment and better immunotherapeutic efficacy in head and neck squamous cell carcinoma

BACKGROUND

PI3K pathway is the most frequently mutated pathway in head and neck squamous cell carcinoma (HNSC), which plays a crucial role in tumorigenesis and progression. In the present study, we aimed to investigate the role of PI3K pathway mutation in clinical prognosis prediction and the relationship with immune microenvironment and response rate to immunotherapy.

METHODS

We collected 129 samples with immunotherapy information from MSKCC-2019 cohort as well as 501 and 40 samples from TCGA-HNSC and MD-Anderson non-immunotherapy cohorts, respectively. Somatic mutation data was utilized to characterize the mutational status of the PI3K pathway. Subsequently, we further analyzed the differences in prognosis, immunotherapy response, genomic alterations, functional characteristics, and immune microenvironment between the mutation and wild groups.

RESULTS

The Kaplan-Meier survival curves displayed that PI3K pathway mutation predicted observably prolonged overall survival (OS) in the immunotherapy cohort MSKCC-2019 (p = 0.012) but did not reach statistical significance in the non-immunotherapy cohorts TCGA-HNSC (p = 0.68) and MD-Anderson (p = 0.68). After incorporating several clinicopathologic features such as age, gender, and tumor mutation burden (TMB), the results of multivariate Cox regression analysis also demonstrated that the PI3K pathway mutation could indicate better immunotherapy outcomes in HNSC patients with a hazard ratio (HR) of 0.533 (95% CI: 0.313-0.910; p = 0.021) in the immunotherapy cohort MSKCC-2019, compared with 0.888 (95% CI: 0.636-1.241; p = 0.487) and 1.939 (95% CI: 0.483-7.781; p = 0.351) in the non-immunotherapy cohorts TCGA-HNSC and MD-Anderson. In addition, the results of the subclass mapping (SubMap) and the tumor immune dysfunction and exclusion (TIDE) also consistently suggested that patients in the mutation group are more likely to benefit from immunotherapy. And further studies showed that the mutation group owned significantly higher TMB, activated immune-related pathways, richer abundance of immune cells, and higher expression levels of immunomodulators. To improve the prognosis of the wild group, we identified five relatively sensitive potential drugs for the wild group, including "BMS-536924," "linsitinib," "NVP-TAE684," "PLX-4720," and "clonazepam."

CONCLUSIONS

The PI3K pathway mutation status could be considered as a potential biomarker to predict better immunotherapeutic efficacy and clinical outcomes after immunotherapy in HNSC patients.

Study of EGFR mutations in head and neck squamous cell carcinomas

Introduction

Squamous carcinoma is the commonest malignancy of the head and neck region. It is associated with high morbidity and mortality. Epidermal growth factor receptor (EGFR) regulates downstream signaling pathways through its tyrosine kinase (TK) domains that play a role in cell proliferation and survival. EGFR mutations have been found to occur between exons 18 to 21 on chromosome 7. Limited studies are available on EGFR-TK mutations in the head and neck squamous cell carcinoma (HNSCC) globally. This study explores EGFR mutations in 30 HNSCC cases presenting to a tertiary care hospital over a period of two years.

Material and Methods

Fresh tumor tissue was collected from the resection specimens of cases of primary HNSCC. Cases with pre-operative therapy were not included. Parameters in the form of patients' age, gender, smoking/tobacco intake, site of the lesion were recorded. Tumor parameters after histopathological examination were recorded in the form of TNM stage, tumor grade. DNA was extracted from fresh tissue of all the cases. EGFR Mutation Analysis Kit assay was used to detect mutations of the EGFR gene. PCR was run and results were analyzed.

Results

EGFR Mutations were found in 6.7%of the patients. There was no significant association of the EGFR Mutation with the studied parameters.

Conclusion

EGFR mutations are present in a subset of patients of HNSCC. Patients having these mutations may benefit from targeted therapy with tyrosine kinase inhibitors.

Prognostic and predictive value of EGFR in head and neck squamous cell carcinoma

EGFR is an extensively studied biomarker in head and neck squamous cell carcinoma (HNSCC). In this review, we discuss the prognostic and predictive role of EGFR in HNSCC, focusing on the different molecular alterations in specific treatment modalities such as radiotherapy alone (RT), combination of surgery, RT and chemotherapy (CT), EGFR inhibitors. We considered EGFR at different molecular levels: protein expression, protein activation, gene copy number, polymorphisms, mutation, EGFRvIII expression and EGFR ligand expression.

Considering RT alone, evidence supports the predictive and prognostic role of high EGFR expression only when evaluated by quantitative assays: this may help select the patients who can mostly benefit from accelerated treatment. Conversely, no predictive biomarkers are available when treatment is a combination of surgery, CT and RT. For this combined treatment, several studies indicate that EGFR expression represents a good prognostic parameter only when measured by a “quantitative” or at least semi-quantitative method. With respect to EGFR inhibitors, neither EGFR expression nor increased gene copy number represent prognostic/predictive factors.

If validated, nuclear EGFR, TGFα levels, EGFR phopshorylation and polymorphisms could represent additional prognostic factors in relation to combination of surgery, CT and RT, while EGFR polymorphisms and high amphiregulin levels could have prognostic value in patients treated with EGFR inhibitors.

Prevalence of EGFR Tyrosine Kinase Domain Mutations in Head and Neck Squamous Cell Carcinoma: Cohort Study and Systematic Review

BACKGROUND

Mutations in the epidermal growth factor receptor (EGFR) tyrosine kinase domain (TKD) are associated with response and resistance to targeted therapy. The EGFR mutation status in patients with advanced oral and oropharyngeal squamous cell carcinoma (OOSCC) was evaluated. A systematic literature review was undertaken to summarize current evidence and estimate the overall prevalence of EGFR TKD mutations in patients with head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

Genomic DNA was extracted from formalin-fixed, paraffin-embedded tumor samples of 113 patients with OOSCC. Pyrosequencing was performed to investigate mutations in EGFR exons 18 to 21. Medline databases were searched for relevant studies. Studies reporting mutations in the EGFR TKD in HNSCC were eligible for inclusion in the systematic review.

RESULTS

No mutations in the EGFR TKD were observed in 113 samples of OOSCC. A total of 53 eligible studies were included in the systematic review. In total, from the review, 117 patients harboring a total of 159 EGFR TKD mutations were reported among 4122 patients with HNSCC. The overall prevalence of EGFR TKD mutations in HNSCC was 2.8%.

CONCLUSION

Large-scale studies are warranted to provide further evidence regarding the mutation status of EGFR in patients with HNSCC.

Molecular Targeting of Growth Factor Receptor Signaling in Radiation Oncology

Ionizing radiation has been shown to activate and interact with multiple growth factor receptor pathways that can influence tumor response to therapy. Among these receptor interactions, the epidermal growth factor receptor (EGFR) has been the most extensively studied with mature clinical applications during the last decade. The combination of radiation and EGFR-targeting agents using either monoclonal antibody (mAb) or small-molecule tyrosine kinase inhibitor (TKI) offers a promising approach to improve tumor control compared to radiation alone. Several underlying mechanisms have been identified that contribute to improved anti-tumor capacity after combined treatment. These include effects on cell cycle distribution, apoptosis, tumor cell repopulation, DNA damage/repair, and impact on tumor vasculature. However, as with virtually all cancer drugs, patients who initially respond to EGFR-targeted agents may eventually develop resistance and manifest cancer progression. Several potential mechanisms of resistance have been identified including mutations in EGFR and downstream signaling molecules, and activation of alternative member-bound tyrosine kinase receptors that bypass the inhibition of EGFR signaling. Several strategies to overcome the resistance are currently being explored in preclinical and clinical models, including agents that target the EGFR T790 M resistance mutation or target multiple EGFR family members, as well as agents that target other receptor tyrosine kinase and downstream signaling sites. In this chapter, we focus primarily on the interaction of radiation with anti-EGFR therapies to summarize this promising approach and highlight newly developing opportunities.

Database of genomic biomarkers for cancer drugs and clinical targetability in solid tumors

SUMMARY

Comprehensive genomic profiling is expected to revolutionize cancer therapy. In this Prospective, we present the prevalence of mutations and copy-number alterations with predictive associations across solid tumors at different levels of stringency for gene-drug targetability. More than 90% of The Cancer Genome Atlas samples have potentially targetable alterations, the majority with multiple events, illustrating the challenges for treatment prioritization given the complexity of the genomic landscape. Nearly 80% of the variants in rarely mutated oncogenes are of uncertain functional significance, reflecting the gap in our understanding of the relevance of many alterations potentially linked to therapeutic actions. Access to targeted agents in early clinical trials could affect treatment decision in 75% of patients with cancer. Prospective implementation of large-scale molecular profiling and standardized reports of predictive biomarkers are fundamental steps for making precision cancer medicine a reality.

The challenge of blocking a wider family members of EGFR against head and neck squamous cell carcinomas

Head and neck squamous cell carcinoma (HNSCC) represent 95% of head and neck cancer with an incidence of over half a million people globally. The prognosis for patients with recurrent or metastatic HNSCC is generally poor with low 5-year survival rates despite treatment advances over the past few decades. Consequently, it is essential to search for new biomarkers and effective therapy options to optimize HNSCC treatment. Epidermal growth factor receptor (EGFR) is overexpressed in approximately 90% of tumours. EGFR has become one of most common targets for new therapies being investigated in HNSCC. In this way, multiple therapies targeting EGFR in HNSCC have been tested but response rates are still low especially in the recurrent or metastatic setting. This has been attributed to mechanisms of resistance to EGFR-targeted therapies. Afatinib, an oral small molecule ErbB Family Blocker that irreversibly binds to ErbB1 (EGFR), ErbB2 (HER2) and ErbB4 (HER4), is being investigated in HNSCC treatment with encouraging phase II results and several ongoing phase III trials. Results of these trials will help to understand the place of afatinib in the HNSCC treatment armamentarium.

Overcoming acquired resistance to cetuximab by dual targeting HER family receptors with antibody-based therapy

Background

Cetuximab, an anti-EGFR monoclonal antibody, is used to treat several cancers. However, many patients who initially respond to cetuximab acquire resistance. To examine mechanisms of acquired resistance, we developed a series of cetuximab-resistant (Ctx^R) clones derived from the cetuximab sensitive (Ctx^S) non-small cell lung cancer (NSCLC) cell line H226. Previous studies characterizing this model revealed that: 1) EGFR was robustly overexpressed in Ctx^R clones due to decreased EGFR ubiquitination and degradation and 2) Ctx^R clones expressed increased HER2 and HER3 activation resulting in constitutive activation of the PI3K/AKT signaling axis. These findings suggest that dual targeting HER family receptors would be highly beneficial in the Ctx^R setting.

Results

Since HER3 has been implicated in resistance to EGFR inhibitors, the efficacy of dually targeting both EGFR and HER3 in Ctx^R models was evaluated. First, EGFR and HER3 expression were knocked down with siRNAs. Compared to the Ctx^S parental cell line (HP), all Ctx^R clones exhibited robust decreases in cell proliferation upon dual knockdown. Analysis of Ctx^R clones indicated that neuregulin-1 was highly overexpressed compared to HP cells. Incubation of HP cells with neuregulin-1 rendered them resistant to cetuximab. Next, dual treatment of Ctx^R clones with cetuximab and the HER3 neutralizing monoclonal antibody (mAb) U3-1287 led to potent anti-proliferative effects. Blockade of EGFR with cetuximab resulted in inactivation of MAPK, while blockade of HER3 with U3-1287 resulted in the inactivation of AKT. Treatment with both mAbs resulted in knockdown of both signaling pathways simultaneously. HER2 was also strongly inactivated upon dual mAb therapy, suggesting that this treatment regimen can diminish signaling from three HER family receptors. De novo Ctx^R H226 mouse xenografts were established to determine if dual therapy could overcome acquired resistance to cetuximab in vivo. Tumors that had acquired resistance to cetuximab were significantly growth delayed upon dual treatment of U3-1287 and cetuximab compared to those continued on cetuximab only. Combinatorial-treated xenograft tumors expressed decreased Ki67 and increased cleaved caspase-3 levels compared to tumors treated with either monotherapy.

Conclusions

These studies demonstrate that dually targeting HER family receptors with antibody-based therapies can overcome acquired resistance to cetuximab.

Influence of epidermal growth factor receptor expression on the cetuximab and panitumumab response rates of head and neck carcinoma cells

OBJECTIVES

To examine the impact of epidermal growth factor receptor (EGFR) expression level on the efficacy of monoclonal antibodies against the EGFR.

METHODS

In four human head and neck carcinoma cell lines, epidermal growth factor expression was knocked down by lentiviral RNA interference. Next, the efficacies of cetuximab and panitumumab at concentrations of 4, 40, and 400 μg/ml were measured by real time cell analysis for a 48-h duration. Finally, the different response rates to the drugs were statistically analyzed.

RESULTS

The lentiviral EGFR knockdown efficiency ranged from 18 to 54 % across all of the cell lines. All original cell lines exhibited rather poor or inverse responses with regard to EGFR-AB treatment. In contrast, inhibiting EGFR expression in the same cell lines yielded statistically significant better responses to cetuximab or panitumumab treatment.

CONCLUSIONS

The cell lines used in this study responded poorly to cetuximab and panitumumab. Better anti-EGFR treatment efficacy was related to lower EGFR expression in head and neck cancer cell lines. These findings might influence the selection of patients to receive cetuximab and panitumumab treatment for head and neck cancer.