Cellular Prion Protein PrPC and Ecto-5'-Nucleotidase Are Markers of the Cellular Stress Response to Aneuploidy.

Aneuploidy is a hallmark of most human tumors, but the molecular physiology of aneuploid cells is not well characterized. In this study, we screened cell surface biomarkers of approximately 300 proteins by multiparameter flow cytometry using multiple aneuploid model systems such as cell lines, patient samples, and mouse models. Several new biomarkers were identified with altered expression in aneuploid cells, including overexpression of the cellular prion protein CD230/PrPC and the immunosuppressive cell surface enzyme ecto-5'-nucleotidase CD73. Functional analyses associated these alterations with increased cellular stress. An increased number of CD73+ cells was observed in confluent cultures in aneuploid cells relative to their diploid counterparts. An elevated expression in CD230/PrPC was observed in serum-deprived cells in association with increased generation of reactive oxygen species. Overall, our work identified biomarkers of aneuploid karyotypes, which suggest insights into the underlying molecular physiology of aneuploid cells. Cancer Res; 77(11); 2914-26. ©2017 AACR.

Association between mutation of the NF2 gene and monosomy 22 in menopausal women with sporadic meningiomas.

BACKGROUND: Meningioma was the first solid tumor shown to contain a recurrent genetic alteration e.g. monosomy 22/del(22q), NF2 being the most relevant gene involved. Although monosomy 22/del(22q) is present in half of all meningiomas, and meningiomas frequently carry NF2 mutations, no study has been reported so far in which both alterations are simultaneously assessed and correlated with the features of the disease. METHODS: Here, we analyzed the frequency of both copy number changes involving chromosome 22 and NF2 mutations in 20 sporadic meningiomas using high-density SNP-arrays, interphase-FISH and PCR techniques. RESULTS: Our results show a significant frequency of NF2 mutations (6/20 patients, 30%), most of which (5/6) had not been previously reported in sporadic meningiomas. NF2 mutations involved five different exons and led to a truncated protein (p.Leu163CysfsX46, p.Phe62LeufsX61, p.Asp281MetfsX15, p.Phe285LeufsX11, p.Gln389ArgfsX37) and an in frame deletion of Phe119. Interestingly, all NF2 mutated cases were menopausal women with monosomy 22 but not del(22q). CONCLUSIONS: These results confirm and extend on previous observations about the high frequency and heterogeneity of NF2 mutations in sporadic meningiomas and indicate they could be restricted to a well-defined cytogenetic and clinical subgroup of menopausal women. Further studies in large series of patients are required to confirm our observations.

Immunophenotypic identification and characterization of tumor cells and infiltrating cell populations in meningiomas.

Meningiomas are primary tumors of the central nervous system composed of both neoplastic and other infiltrating cells. We determined the cellular composition of 51 meningioma samples by multiparameter flow cytometric (MFC) immunophenotyping and investigated the potential relationship between mRNA and protein expression levels of neoplastic cells. For immunophenotypic, morphologic, and cytogenetic characterization of individual cell populations, a large panel of markers was used together with phagocytic/endocytic functional assays and MFC sorting. Overall, our results revealed coexistence of CD45(-) neoplastic cells and CD45(+) immune infiltrating cells in all meningiomas. Infiltrating cells included tissue macrophages, with an HLA-DR(+)CD14(+)CD45(+)CD68(+)CD16(-/+)CD33(-/+) phenotype and high phagocytic/endocytic activity, and a small proportion of cytotoxic lymphocytes (mostly T CD8(+) and natural killer cells). Tumor cells expressed multiple cell adhesion proteins, tetraspanins, HLA-I/HLA-DR molecules, complement regulatory proteins, cell surface ectoenzymes, and growth factor receptors. Noteworthy, the relationship between mRNA and protein levels was variable, depending on the proteins evaluated and the level of infiltration by immune cells. In summary, our results indicate that MFC immunophenotyping provides a reliable tool for the characterization of the patterns of protein expression of different cell populations coexisting in meningioma samples, with a more accurate measure of gene expression profiles of tumor cells at the functional/protein level than conventional mRNA microarray, independently of the degree of infiltration of the tumor by immune cells.