Mass spectrometry imaging combined with top-down proteomics to predict a more accurate immunotherapyresponse in non-small cell lung cancer patients

Non-small cell lung cancer (NSCLC), accounting for 80-85% of all lung cancer cases, is generally linked with a poor prognosis and is one of the leading causes of cancer-related deaths worldwide for both women and men. Recently, immunotherapy has changed the landscape of NSCLC treatment. For those who respond, promising results, in terms of acceptable side-effects and antitumor activity by restoring host immunity, have been achieved in NSCLC patients by therapeutic blocking of immune checkpoint programmed cell death protein 1 (PD-1) and its ligand PD-L1. Unfortunately, to date, only a subgroup of patients experiences any long term benefit, while severe immune-related toxicities may occur in patients that do not clinically respond to the therapy. To avoid unnecessary costs and toxicities in patients who will not clinically respond, unique response patterns for anti-PD-(L)1 immunotherapy and additional biomarkers need to be discovered to overcome the limitations of PD-L1 as the sole predictive biomarker in clinical use. Proteomic approaches, in particular mass spectrometry, have already proven their relevance in discovery of new biomarkers, allowing early diagnosis or prediction of therapy response resulting in a better patient’s quality of life and improvement of health care. In this study, we demonstrated how the combinatorial use of mass spectrometry imaging (MSI) with top-down proteomics on NSCLC tissues was used to discover three candidate predictive biomarkers for anti-PD-(L)1 immunotherapy response in NSCLC patients. Evaluation of these three candidate predictive biomarkers (i.e. neutrophil defensin 1, neutrophil defensin 2 and neutrophil defensin 3) was performed with mass spectrometry imaging and verified with traditional immunohistochemistry and corresponding statistical analysis. The findings reported suggest the possible association between neutrophil defensin expression and response to anti-PD-(L)1 immunotherapy for a more accurate therapy decision for NSCLC patients. Finally, we demonstrated with in vitro physiological data that neutrophil defensin 1, 2 and 3 show an immune-stimulatory effect towards lung cancer. In conclusion, implementation of MSI and top-down proteomics in lung cancer research has led to the discovery of neutrophil defensins as biomarker to differentiate which NSCLC patients will benefit from anti-PD-(L)1 immunotherapy. MSI has further been used as a successful screening method to evaluate expression levels of these molecules in pretreatment biopsies, confirmed by immunohistochemical analysis. Lastly, the newly discovered neutrophil defensin biomarkers show potential as new molecular targets, essential for designing new effective therapeutic strategies.

Publication year:2020

Keywords:Doctoral thesis

Accessibility:Open