Proteomic analysis of PTCH1+/- fibroblast lysate and conditioned culture media isolated from the skin of healthy subjects and Nevoid Basal Cell Carcinoma Syndrome (NBCCS) patients

PTCH1 mutations lead to complex syndromes such as the Gorlin Syndrome (GS) also named Nevoid basal Cell Carcinoma Syndrome (NBCCS, OMIM #109400) is a rare autosomal dominant disorder characterized by striking predisposition to the development of multiple basal cell carcinomas (BCCs), keratocystic odontogenic tumors (KOCTs) of the jaws, palmar and/or plantar pits and developmental defects. A variety of other benign or malignant tumors i.e., ovarian fibroma, medulloblastoma, rhabdomyosarcoma, cardiac fibroma and ameloblastoma can be found. The mechanisms underlying the increased predisposition to the development of BCCs in the context of Gorlin-Goltz syndrome is linked to molecular pathways that differ from sporadic cases. Patients with Gorlin syndrome tend to develop multiple BCCs at an early age: moreover, the tumors typically arise on non-sunexposed skin. Fibroblasts of patients with Gorlin Syndrome may display properties determining BCC development. The aim of this study was to compare the proteomic profile of cultured fibroblast and fibroblast conditioned culture media of PTCH1+ and non-mutated fibroblasts. Proteomic analyses was performed using Surface-Enhanced Laser Desorption/Ionization Time-of-Flight mass spectrometry in PTCH1+ fibroblast conditioned media isolated from not affected sun-protected skin areas of Gorlin patients and from healthy subjects. The protein profiles were obtained using Copper pre-activated IMAC30 ProteinChip array. 12 protein cluster peaks, >5 kDa, had statistically significant differences in their peak intensities between PTCH1+ and PTCH1- subject groups (p<0.05). Protein profiles in the fibroblast conditioned media revealed statistically significant differences between two different types (missense vs nonsense) of PTCH1 mutations. These differences could be useful as signatures to identify PTCH1 gene carriers at high risk for the development of NBCCS-associated malignancies, and to develop novel experimental molecular tailored therapies based on these druggable targets. These protein peaks profiles provided better understanding of the complex skin cancer microenvironment and could be useful to select patients at risk to develop multiple and aggressive BCCs and/or other NBCCS-associated malignancies.