Native Human PRTN3 Antigen

Recent studies of mammalian genomes suggest that alternative promoters are associated with various disorders, including cancer. Here we present an intronic promoter of the murine proteinase 3 gene, which drives the expression of an alternative mRNA in intron 2 of the prtn3 gene. The proximal promoter sequences were identified and a series of promoter deletion constructs were used to identify the sequence elements that are required for basal promoter activity. Expression of the homeobox transcription factor CUX1 p75 isoform was found to suppress the activity of the alternative PR3 promoter. Data base analyses, multiple alignments and expression data showed that the intronic PR3 promoter is active in leukemia and other tumor cells as well as in mouse embryo, male mammary gland and bone marrow. In the spleen, the transcript is exclusively expressed by Gr-1(int)/CD11b(+) cells, which are also known as myeloid-derived suppressor cells (MDSCs). In humans, an alternative transcript of the PR3-gene could be detected in the bone marrow and in various cancer cell lines but not in primary leukemia cells, suggesting a species-overarching function of this kind of promoter. Therefore, the alternative PR3 promoter and its mRNA may be useful tools to investigate the fate of hematopoietic stem cells. (c) 2012 Wiley Periodicals, Inc.

t(8;21)(q22;q22) acute myelogenous leukemia (AML) is morpho-logically characterized by a continuum of heterogeneous leukemia cells from myeloblasts to differentiated myeloid elements. Thus, t(8;21) AML is an excellent model for studying heterogeneous cell populations and cellular evolution during disease progression. Using integrative analyses of immunophenotype, RNA-sequencing (RNA-seq), and single-cell RNA-sequencing (scRNA-seq), we identi-fied three distinct intrapatient leukemic cell populations that were arrested at different stages of myeloid differentiation: CD34*CD117dim blasts, CD34*CD117bri blasts, and abnormal myeloid cells with partial maturation (AM). CD117 is also known as c-KIT protein. CD34*CD117dim cells were blocked in the G0/G1 phase at disease onset, presenting with the regular morphology of myeloblasts showing features of granulocyte-monocyte progenitors (GMP), and were drug-resistant to chemotherapy. Genes associated with cell migration and adhe-sion (LGALS1, EMP3, and ANXA2) were highly expressed in the CD34*CD117dim population. CD34*CD117bri blasts were blocked a bit later than the CD34*CD117dim population in the hematopoietic differentiation stage and displayed high proliferation ability. AM cells, which bear abnormal myelocyte morphology, especially over -expressed granule genes AZU1, ELANE, and PRTN3 and were sensi-tive to chemotherapy. scRNA-seq at different time points identified CD34*CD117dim blasts as an important leukemic cluster that ex-panded at postrelapse refractory stage after several cycles of che-motherapy. Patients with t(8;21) AML with a higher proportion of CD34*CD117dim cells had significantly worse clinical outcomes than those with a lower CD34*CD117dim proportion. Univariate and mul-tivariate analyses identified CD34*CD117dim proportion as an inde-pendent factor for poor disease outcome. Our study provides evidence for the multidimensional heterogeneity of t(8;21)AML and may offer new tools for future disease stratification.