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 ~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

The sialyl-glycolipid stage-specific embryonic antigen 4 marks a subpopulation of chemotherapy-resistant breast cancer cells with mesenchymal features

INTRODUCTION: Chemotherapy resistance resulting in incomplete pathologic response is associated with high risk of metastasis and early relapse in breast cancer. The aim of this study was to identify and evaluate biomarkers of treatment-resistant tumor cells. METHODS: We performed a cell surface marker screen in triple-negative breast cancer patient-derived xenograft models treated with standard care genotoxic chemotherapy. Global expression profiling was used to further characterize the identified treatment-resistant subpopulations. RESULTS: High expression of sialyl-glycolipid stage-specific embryonic antigen 4 (SSEA4) was found in residual tumor cells surviving chemotherapy and in samples from metastatic patients who relapsed after neoadjuvant chemotherapy. Gene and microRNA (miRNA) expression profiling linked SSEA4 positivity with a mesenchymal phenotype and a deregulation of drug resistance pathways. Functional assays demonstrated a direct link between epithelial-mesenchymal transition (EMT) and SSEA4 expression. Interestingly, SSEA4 expression, EMT, and drug resistance seemed to be regulated posttranscriptionally. Finally, high expression of CMP-N-acetylneuraminate-β-galactosamide-α-2,3-sialyltransferase 2 (ST3GAL2), the rate-limiting enzyme of SSEA4 synthesis, was found to be associated with poor clinical outcome in breast and ovarian cancer patients treated with chemotherapy. CONCLUSIONS: In this study, we identified SSEA4 as highly expressed in a subpopulation of tumor cells resistant to multiple commonly used chemotherapy drugs, as well as ST3GAL2, the rate-limiting enzyme of SSEA4 synthesis, as a predictive marker of poor outcome for breast and ovarian cancer patients undergoing chemotherapy. Both biomarkers and additionally identified regulatory miRNAs may be used to further understand chemoresistance, to stratify patient groups in order to avoid ineffective and painful therapies, and to develop alternative treatment regimens for breast cancer patients

Boletín de Segovia: Número 30 - 1918 marzo 11

Copia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 200

Additional file 5: Figure S3. of The sialyl-glycolipid stage-specific embryonic antigen 4 marks a subpopulation of chemotherapy-resistant breast cancer cells with mesenchymal features

Correlation among CD24-, CD44-, and SSEA4-expressing subpopulations. To address the correlation between CD24, CD44, and SSEA4 expression, we performed costaining of these markers on residual tumor nodules after AC chemotherapy and untreated tumors of three independent models: HBCx-6 (a), HBCx-10 (b), and HBCx-14 (c). Regulation of the three markers did not correlate among the treatment cycles. (PNG 1664 kb

Additional file 9: Table S3. of The sialyl-glycolipid stage-specific embryonic antigen 4 marks a subpopulation of chemotherapy-resistant breast cancer cells with mesenchymal features

Results of microarray analysis. Results of gene and miRNA expression profiling, Gene Ontology analysis, and miRNA target prediction. (XLSX 118 kb

Additional file 1: of The sialyl-glycolipid stage-specific embryonic antigen 4 marks a subpopulation of chemotherapy-resistant breast cancer cells with mesenchymal features

Supplemental experimental procedures. Detailed description of materials and methods. (DOCX 62 kb

Additional file 12: Figure S8. of The sialyl-glycolipid stage-specific embryonic antigen 4 marks a subpopulation of chemotherapy-resistant breast cancer cells with mesenchymal features

SSEA4-positive breast cancer cells show decreased expression of miRNAs inhibiting EMT inducers. Expression ratios of the 12 miRNAs targeting the key mesenchymal regulator and indicator genes ZEB1, ZEB2, fibronectin 1, Snail1, Snail2, and Twist. Each bar represents the log2 expression ratio of the SSEA4-positive fraction relative to the SSEA4-negative fraction for the respective tumor model. (TIFF 201 kb