Better to be alone than in bad company:The antagonistic effect of cisplatin and crizotinib combination therapy in non-small cell lung cancer

AIM To investigate the potential benefit of combining the cMET inhibitor crizotinib and cisplatin we performed in vitro combination studies.METHODS We tested three different treatment schemes in four non-small cell lung cancer(NSCLC) cell lines with a different cMET/epidermal growth factor receptor genetic background by means of the sulforhodamine B assay and performed analysis with Calcusyn.RESULTS All treatment schemes showed an antagonistic effect in all cell lines,independent of the cMET status.Despite their different genetic backgrounds,all cell lines(EBC-1,HCC827,H1975 and LUDLU-1) showed antagonistic combination indexes ranging from 1.3-2.7.These results were independent of the treatment schedule.CONCLUSION These results discourage further efforts to combine cMET inhibition with cisplatin chemotherapy in NSCLC.

Establishment of head and neck squamous cell carcinoma mouse models for cetuximab resistance and sensitivity

Aim:Acquired resistance to the targeted agent cetuximab poses a significant challenge in finding effective anti-cancer treatments for head and neck squamous cell carcinoma(HNSCC).To accurately study novel combination treatments,suitable preclinical mouse models for cetuximab resistance are key yet currently limited.This study aimed to optimize an acquired cetuximab-resistant mouse model,with preservation of the innate immunity,ensuring intact antibody-dependent cellular cytotoxicity(ADCC)functionality.Methods:Cetuximab-sensitive and acquired-resistant HNSCC cell lines,generated in vitro,were subcutaneously engrafted in Rag2 knock-out(KO),BALB/c Nude and CB17 Scid mice with/without Matrigel or Geltrex.Once tumor growth was established,mice were intraperitoneally injected twice a week with cetuximab for a maximum of 3 weeks.In addition,immunohistochemistry was used to evaluate the tumor and its microenvironment.Results:Despite several adjustments in cell number,cell lines and the addition of Matrigel,Rag2 KO and BALB/C Nude mice proved to be unsuitable for xenografting our HNSCC cell lines.Durable tumor growth of resistant SC263-R cells could be induced in CB17 Scid mice.However,these cells had lost their resistance phenotype in vivo.Immunohistochemistry revealed a high infiltration of macrophages in cetuximab-treated SC263-R tumors.FaDu-S and FaDu-R cells successfully engrafted into CB17 Scid mice and maintained their sensitivity/resistance to cetuximab.Conclusion:We have established in vivo HNSCC mouse models with intact ADCC functionality for cetuximab resistance and sensitivity using the FaDu-R and FaDu-S cell lines,respectively.These models serve as valuable tools for investigating cetuximab resistance mechanisms and exploring novel drug combination strategies.

Characterization of acquired nutlin-3 resistant non-small cell lung cancer cells

Aim:The purpose of this manuscript is to study the potential characteristics of acquired nutlin-3 resistant non-small cell lung cancer cells(NSCLC).Nutlin-3 is an inhibitor of the murine-double minute 2 protein,the main negative regulator of wild type p53,of which several derivatives are currently in clinical development.Methods:A549 NSCLC cells were exposed to increasing concentrations of nutlin-3 for a period of 18 weeks.Monoclonal derivates were cultured,and the most resistance subclone was selected for whole transcriptome analysis.Gene set enrichment analysis was performed on differentially expressed genes between A549 nutlin-3 resistant cancer cells and the parental A549 p53 wild type cancer cells.Relevant findings were validated at the gene,protein and/or functional level.Results:All nutlin-3 resistant subclones acquired mutations in the TP53 gene,resulting in overexpression of the mutant p53 protein.The most resistant subclone was enriched for genes related to epithelial to mesenchymal transition(EMT),resulting in increased migratory and invasive potential.Furthermore,these cells were enriched in genes related to inflammation,tissue remodelling,and angiogenesis.Importantly,expression of several immune checkpoints,including PD-L1 and PD-L2,was significantly upregulated,and cisplatin-induced cell death was reduced.Conclusion:Transcriptome analysis of a highly nutlin-3 resistant A549 subclone shows the relevance of studying(1)resistance to standard of care chemotherapy;(2)secretion of immunomodulating chemo-and cytokines;(3)immune checkpoint expression;and(4)EMT and invasion in nutlin-3 resistant cancer cells in addition to acquired mutations in the TP53 gene.