Background The epidermal growth factor receptor (EGFR) is a key protein involved in cancer development. Monoclonal antibodies targeting EGFR are approved for the treatment of metastatic colorectal... Show moreBackground The epidermal growth factor receptor (EGFR) is a key protein involved in cancer development. Monoclonal antibodies targeting EGFR are approved for the treatment of metastatic colorectal cancer (CRC). Despite the beneficial clinical effects observed in subgroups of patients, the acquisition of resistance to treatment remains a major concern. Protein N-glycosylation of cellular receptors is known to regulate physiological processes leading to activation of downstream signaling pathways. In the present study, the role of EGFR-specific terminal alpha 2,6-sialylation was analyzed in modulation of the malignant phenotype of CRC cells and their resistance to monoclonal antibody Cetuximab-based therapy.Methods Glycoengineered CRC cell models with specific sialyltransferase ST6GAL1 expression levels were applied to evaluate EGFR activation, cell surface glycosylation and therapeutic response to Cetuximab.Results Glycoproteomic analysis revealed EGFR as a major target of ST6Gal1-mediated alpha 2,6-sialylation in a glycosite-specific manner. Mechanistically, CRC cells with increased ST6Gal1 expression and displaying terminal alpha 2,6-sialylation showed a marked resistance to Cetuximab-induced cytotoxicity. Moreover, we found that this resistance was accompanied by downregulation of EGFR expression and its activation.Conclusions Our data indicate that EGFR alpha 2,6-sialylation is a key factor in modulating the susceptibility of CRC cells to antibody targeted therapy, thereby disclosing a potential novel biomarker and providing key molecular information for tailor made anti-cancer strategies. Show less
Purpose Evidence-based guidelines on how to prevent or treat cetuximab-related skin reactions are lacking and multiple care and management strategies are used. The main purpose of the present study... Show morePurpose Evidence-based guidelines on how to prevent or treat cetuximab-related skin reactions are lacking and multiple care and management strategies are used. The main purpose of the present study is to gain information about the different skincare products being used against skin reactions in metastatic colorectal cancer (mCRC) and recurrent/metastatic (R/M) or locally advanced (LA) squamous cell cancer of the head and neck (SCCHN) patients treated with cetuximab. Methods An open-label, prospective observational study conducted in the Netherlands. The occurrence of skin reactions and the care and management options taken were documented for 16 weeks, starting from the first administration of cetuximab. Results A total of 103 patients were included in 7 hospitals. 38 patients (37%) developed a grade >= 2 skin reaction. Eighty-six patients could be analysed for the primary endpoint (73.3% males, mean age 62.4 years, n = 44 LA SCCHN, n = 16 R/M SCCHN, n = 26 mCRC). The most frequently used skin products at some point during the observation period were moisturizing products (70%), systemic antibiotics (64%), topical antibiotics (58%), lipid-regenerating (28%) and other topical products (28%). The overall use of products gradually increased from baseline to week 6-10, reducing by week 16. Hospital protocols were the primary reason (> 50%) for choice of the skincare products and medications. Conclusion A variety of skin care products and antibiotics were commonly used. Only few patients developed severe cutaneous reactions. For patients, the occurrence of skin reactions did not influence their willingness to continue cetuximab therapy. Show less
The use of the epidermal growth factor receptor (EGFR) antibodies cetuximab and panitumumab is limited to colorectal cancer (CRC) patients with KRAS wild type tumors and more recently in RAS wild... Show moreThe use of the epidermal growth factor receptor (EGFR) antibodies cetuximab and panitumumab is limited to colorectal cancer (CRC) patients with KRAS wild type tumors and more recently in RAS wild type only. After having become chemotherapy refractory, treatment options are limited for this substantial patient group. This means that there is an urgent need to optimize anti-EGFR therapy. The work presented in this thesis aimed at optimising EGFR targeted monoclonal antibody therapy in metastatic CRC. This thesis investigates several strategies to refine EGFR targeted monoclonal antibody therapy in CRC by: 1. statins and their ability to phenoconvert KRAS mutant CRC; __ 2. exploration of polymorphisms in the gene encoding FCGR3A and their association __with cetuximab efficacy; __ 3. and investigating the pharmacokinetics of cetuximab and panitumumab in patients with renal or hepatic dysfunction. __ Show less
Osteosarcoma and Ewing sarcoma are the most common bone cancers in children and young adults. Despite advanced surgical techniques and multi-drug chemotherapy, patients with recurrent, metastatic... Show moreOsteosarcoma and Ewing sarcoma are the most common bone cancers in children and young adults. Despite advanced surgical techniques and multi-drug chemotherapy, patients with recurrent, metastatic or chemotherapy-resistant disease have a poor outcome. Thus, novel targeted therapies are needed that combine potent and specific anti-cancer activity with limited toxicity toward normal tissues. The thesis is introduced by an outline of the biological properties of osteosarcoma and Ewing sarcoma, followed by an overview of cancer immunology and immunotherapy with the primary focus on innate immunity of human natural killer (NK) cells and macrophages. In the research chapters, cellular interactions of NK cells and macrophages with bone tumor cells are characterized in order to achieve favorable effects on anti-cancer immune cell functions. It is demonstrated that the anti-cancer potential of especially NK cells but also macrophages can be enhanced and directed to the bone tumor cells. It is discussed that the modulation of tumor__immune cell interactions may help to design novel immunotherapeutic approaches to harness anti-cancer functions of innate immune cells against osteosarcoma and Ewing sarcoma. Show less
Background: Failure of locoregional control is the main cause of recurrence in advanced head and neck cancer. This multi-center trial aims to improve outcome in two ways. Firstly, by redistribution... Show moreBackground: Failure of locoregional control is the main cause of recurrence in advanced head and neck cancer. This multi-center trial aims to improve outcome in two ways. Firstly, by redistribution of the radiation dose to the metabolically most FDG-PET avid part of the tumour. Hereby, a biologically more effective dose distribution might be achieved while simultaneously sparing normal tissues. Secondly, by improving patient selection. Both cisplatin and Epidermal Growth Factor Receptor (EGFR) antibodies like Cetuximab in combination with Radiotherapy (RT) are effective in enhancing tumour response. However, it is unknown which patients will benefit from either agent in combination with irradiation. We will analyze the predictive value of biological markers and Zr-89-Cetuximab uptake for treatment outcome of chemoradiation with Cetuximab or cisplatin to improve patient selection.Methods: ARTFORCE is a randomized phase II trial for 268 patients with a factorial 2 by 2 design: cisplatin versus Cetuximab and standard RT versus redistributed RT. Cisplatin is dosed weekly 40 mg/m(2) for 6 weeks. Cetuximab is dosed 250mg/m(2) weekly (loading dose 400 mg/m(2)) for 6 weeks. The standard RT regimen consists of elective RT up to 54.25 Gy with a simultaneous integrated boost (SIB) to 70 Gy in 35 fractions in 6 weeks. Redistributed adaptive RT consists of elective RT up to 54.25 Gy with a SIB between 64-80 Gy in 35 fractions in 6 weeks with redistributed dose to the gross tumour volume (GTV) and clinical target volume (CTV), and adaptation of treatment for anatomical changes in the third week of treatment.Patients with locally advanced, biopsy confirmed squamous cell carcinoma of the oropharynx, oral cavity or hypopharynx are eligible.Primary endpoints are: locoregional recurrence free survival at 2 years, correlation of the median Zr-89-cetuximab uptake and biological markers with treatment specific outcome, and toxicity. Secondary endpoints are quality of life, swallowing function preservation, progression free and overall survival.Discussion: The objective of the ARTFORCE Head and Neck trial is to determine the predictive value of biological markers and Zr-89-Cetuximab uptake, as it is unknown how to select patients for the appropriate concurrent agent. Also we will determine if adaptive RT and dose redistribution improve locoregional control without increasing toxicity. Show less
In this thesis, several aspects and cellular players involved in the immune response to (HPV-induced) tumors were investigated. In chapter 2 a detailed analysis of HPV-specific immunity in a large... Show moreIn this thesis, several aspects and cellular players involved in the immune response to (HPV-induced) tumors were investigated. In chapter 2 a detailed analysis of HPV-specific immunity in a large group of patients with HPV-induced cervical cancer (CxCa) in relation to HLA-types and prognostic factors was performed. In 30% of the tested patients, circulating HPV specific T cells were found, most often in patients with deeply infiltrating tumors. In this group, patients with HPV specific proliferative immunity displayed better disease free survival. It was shown earlier by Piersma et al [69] that only in 30% of TIL populations, HPV specific T cells were found. In chapter 3 an in depth analysis of the breadth and type of HPV specific T-cell populations in tumor infiltrating T cell (TIL) cultures or LN cells from HPV 16 or 18 positive CxCa patients was performed. We found that if patients displayed a HPV-specific T cell response, this was surprisingly broad. Despite recognition, a number of cells did not produce type 1 cytokines and therefore we tested what TLR-agonist was able to support cytokine induction by these T cells. In chapter 4 we asked the question whether HPV-specific T cells play a role in HPV-induced HNSCC. We hypothesize that HPV-induced tumors are more immunogenic and stimulate strong T-cell reactivity to the viral oncoproteins in contrast to HPV-negative tumors. We set up a pilot study to investigate whether HPV is present in HNSCC in the Dutch patient population and at which anatomical site. Accordingly, blood and tumor infiltrating T cells were analyzed for the presence of functional HPV specific T cells. The lack of T cell responses in CxCa patients and the __poised__ function of tumor-antigen specific T cells could be a lack of proper priming by DC. Therefore we investigated in chapter 5A the effects of CxCa produced soluble factors on the differentiation of antigen presenting cells (APC). Several tumor cell lines hampered DC differentiation or even skewed monocyte differentiation into tolerogenic tumor promoting M2 macrophages. We identified the factors responsible for this and investigated the outcome of the interaction of HPV specific T-cell clones with these macrophages. Since patients with advanced or recurrent disease are treated with platinum based chemotherapy we investigated the immune-modulating effect of this therapy on tumor cells, tumor-modulated APC and subsequent interaction with T cells. This ongoing work is summarized in chapter 5B. Therapeutic vaccination is being developed for treatment of chronic infections and cancer, and aims to generate protective T-cell immunity. Although some clinical successes have been reported, particularly in the field of cancer vaccination, there is still much to be gained in terms of efficacy [91,92]. Especially the adjuvant used and the route of administration of vaccines are critical factors that determine the type and memory of the resulting T-cell response. Intradermal vaccination is an attractive method for diseases in the skin such as HPV induced tumors and melanomas since the induced T cells get skin-homing instructions. In chapter 5 we showed already that highly pure DC can become activated by the addition of several different TLR agonists in vitro. To assess the effect of these TLR agonists on the APC present in the dermis, a human skin-explant model was used to analyze the phenotype and function of the APC migrating out the skin upon TLR-injection. These results are described in chapter 6. Surprisingly, only few TLR-agonists turned out to induce activation of the migrating cells. The current treatment of patients with advanced colorectal cancer consists of chemotherapy together with the MAb bevacizumab that blocks soluble VEGF. The addition of a second antibody that targets tumor expressed EGFR (cetuximab) to this treatment did not result in the expected disease free survival benefit in a large randomized phase III study (CAIROII). Analysis of gene polymorphisms in the Fc__Receptors revealed that patients with the high affinity FCGR3A polymorphism did significantly worse upon addition of cetuximab to the standard treatment. As colon cancers are generally infiltrated with macrophages we tested the hypothesis that membrane bound antibodies could activate tumor promoting M2 macrophages and that this would happen more efficiently in patients with high affinity FCGRIIIA in chapter 7. In chapter 8 the work of this thesis is discussed in light of recent literature. Show less
Even though treatment of several types of solid tumors has improved in the past few years with the introduction of the monoclonal antibodies against the epidermal growth factor receptor (EGFR) and... Show moreEven though treatment of several types of solid tumors has improved in the past few years with the introduction of the monoclonal antibodies against the epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF), the clinical benefit of these targeted therapies is modest. Pharmacogenetics has the potential to select patients with higher chance of response to agents that target these pathways. In the thesis, we describe the association of the FCGR3A Phe158Val polymorphism with progression-free survival in advanced colorectal cancer patients treated with cetuximab added to chemotherapy and bevacizumab. Following this finding, we found that cetuximab activates type 2 macrophages, which could have a negative effect on the clinical efficacy of cetuximab. Furthermore, we detected a genetic interaction profile consisting of the VEGF +405G>C and TYMS TSER polymorphisms, that was associated with the efficacy of capecitabine, oxaliplatin and bevacizumab in advanced colorectal cancer patients. Finally, we performed a genome wide association study with the same treatment, in which polymorphisms in the proximity of the AGPAT5 gene were associated with progression-free survival Show less
