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Summary Proline-directed phosphorylation is regulated by the prolyl isomerase Pin1, which plays a fundamental role in driving breast cancer stem-like cells (BCSCs). Rab2A is a small GTPase critical for vesicle trafficking. Here, we show that Pin1 increases Rab2A transcription to promote BCSC expansion and tumorigenesis in vitro and in vivo. Mechanistically, Rab2A directly interacts with and prevents dephosphorylation/inactivation of Erk1/2 by the MKP3 phosphatase, resulting in Zeb1 upregulation and β-catenin nuclear translocation. In cancer cells, Rab2A is activated via gene amplification, mutation or Pin1 overexpression. Rab2A overexpression or mutation endows BCSC traits to primary normal human breast epithelial cells, whereas silencing Rab2A potently inhibits the expansion and tumorigenesis of freshly isolated BCSCs. Finally, Rab2A overexpression correlates with poor clinical outcome in breast cancer patients. Thus, Pin1/Rab2A/Erk drives BCSC expansion and tumorigenicity, suggesting potential drug targets. [ABSTRACT FROM AUTHOR]

Abstract: Analysis of chromosomal changes in esophageal squamous cell carcinoma (ESCC) can illuminate the molecular mechanisms underlying the development and progression of this cancer, which is among the 10 most common malignant tumors. Cell lines are better suited than surgical samples for chromosome analysis in this cancer. This study used multicolor fluorescence in situ hybridization (M-FISH) to characterize the molecular cytogenetics of ESCC in cell line KYSE180. Two pools of 12-color whole-chromosome painting probes were designed, and two rounds of FISH were performed on the same metaphase spreads. Loss of DNA copy number was observed at 4p, 5q, 6q, 9, 10p, 12p, 13, 14p, 15p, 18p, 18q, 20, 22, and Y. Chromosomal gains and translocations occurred at the entire or part of 1, 2p, 3, 4p, 5p, 5q, 6p, 7, 8, 10q, 11, 12q, 14q, 16, 17q, 19, and Xp. Seven derivative chromosomes (5, 8, 12, 14, 14, 14, and 17) presented complex translocations, each involving three or four chromosomes. No chromosomes 9, 13, or Y were detected. These results add significant information to the existing karyotype description of KYSE180 and provide detailed cytogenetic background data for appropriate use of the cell line. [Copyright &y& Elsevier]