Proteome profiling of keratinocytes transforming to malignancy

Abstract

To shed light on the multistep process of squamous cell carcinoma development and the underlying pathologic mechanisms, we performed comparative proteome analysis of keratinocytes, keratinocytes stimulated with Il-1beta, and A431 epidermoid carcinoma cells. Fractionation of the cells into supernatant, nucleus, and cytoplasm was followed by protein separation, proteolytic digest, and nano-LC separation, and fragmentation using an ion trap mass spectrometer. Specific bioinformatics tools were used to generate a list of keratinocyte-specific proteins. Ninety percent of these proteins were found to be upregulated in keratinocytes versus the A431 cells. Classification of the identified proteins by biologic function and gene set enrichment analysis revealed that keratinocytes produced more proteins involved in cell differentiation, cell adhesion, cell junction, calcium ion, calmodulin binding, cytoskeleton organization, and cytokinesis, whereas A431 produced more proteins involved in cell cycle checkpoint, cell cycle process, RNA processing and transport, DNA damage and repair, RNA and DNA binding, and chromatin remodeling. The protein signatures of A431 and normal keratinocytes treated with IL-1beta showed marked similarity, confirming that inflammation is an important step in malignant transformation in nonmelanoma skin cancer. Thus, proteome profiling and bioinformatic processing may support the understanding of the underlying mechanisms, with the potential to facilitate development of early biomarkers and patient-tailored therapy.

From Normal Skin to Squamous Cell Carcinoma: A Quest for Novel Biomarkers

“…Moreover, stimulation with IL-1 beta increased the level of proteins involved in nuclear factor kappa B (NF- κ B) communication pathway, in angiogenesis, and of those with antiapoptotic effect. Similar changes were found in epidermoid carcinoma cells suggesting an important role of inflammation in skin carcinogenesis [36]. …”

“…A recent in vitro study [36] has identified 50 proteins considered specific to keratinocytes, most of them directly related to keratinocyte physiology. Some of these proteins, such as alpha-2 macroglobulin-like protein-1, alpha-2 macroglobulin-like protein 2, and interferon regulatory factor 6 (IRF-6) are involved in keratinocyte proliferation and differentiation.…”

Inhibition of the mevalonate pathway affects epigenetic regulation in cancer cells

“…PathVisio software (23) was applied for specific analyses of defined pathways from Affymetrix arrays (Type Human Gene 1.0 ST Array). Proteomics analyses were conducted as described (24,25) .…”

Non Melanoma Skin Cancer Pathogenesis Overview

“…UV exposure is considered as a complete carcinogen, since it affects each stage of carcinogenesis. In fact, it leads to cellular damage because of the reduction of cell-mediated immune responses, production of reactive oxygen species (ROS) and DNA alteration [ 5 , 6 , 7 , 8 ]. The earliest event after high UV exposure is keratinocyte apoptosis led by the p53/p21/bax/bcl-2 pathway followed by a hyperproliferative phase, leading to epidermal hyperplasia [ 5 , 6 ].…”