Standardized high-sensitivity flow cytometry testing for paroxysmal nocturnal hemoglobinuria in children with acquired bone marrow failure disorders: A single center US study.

BACKGROUND: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hematopoietic stem cell disorder that has not been well-documented in children, particularly those with acquired bone marrow failure disorders (ABMFD)-acquired aplastic anemia (AAA) and myelodysplastic syndrome (MDS). Therefore, we sought to determine the prevalence of PNH populations in children with ABMFD. METHODS: PNH testing was performed in children with an ABMFD diagnosis using high sensitivity (≥0.01%) fluorescent aerolysin (FLAER)-based assay according to 2010 International Clinical Cytometry Society (ICCS) PNH Consensus Guidelines and 2012 Practical PNH Guidelines. FLAER/CD64/CD15/CD24/CD14/CD45 and CD235a/CD59 panels were used for white blood cell and red blood cell testing, respectively. RESULTS: Thirty-seven patients with ABMFD (34 AAA, 3 MDS) were included (17M/20F, age 2-18 years, median 9 years). PNH populations were identified in 17 of 37 (46%) patients. Of the 17 patients with PNH populations identified, 7 were PNH clones (>1% PNH population), and 10 had minor PNH population or rare cells with PNH phenotype (≤1% PNH population). CONCLUSIONS: This is the first study to use a standardized high-sensitivity FLAER-based flow cytometry assay and the recommended cutoff of 0.01% to identify cells with PNH phenotype in pediatric patients with ABMFD in the United States. The identification of a PNH population in 46% of ABMFD supports the recommendation for high sensitivity PNH testing in children with these disorders. As a less sensitive assay using a cutoff of ≥ 1% PNH population would have missed 10 (27%) patients with minor PNH population or rare cells with PNH phenotype. © 2017 International Clinical Cytometry Society.

Extracellular matrix scaffold for cardiac repair.

BACKGROUND: Heart failure remains a significant problem. Tissue-engineered cardiac patches offer potential to treat severe heart failure. We studied an extracellular matrix scaffold for repairing the infarcted left ventricle. METHODS AND RESULTS: Pigs (n=42) underwent left ventricular (LV) infarction. At 6 to 8 weeks, either 4-layer multilaminate urinary bladder-derived extracellular matrix or expanded polytetrafluoroethlyene (ePTFE) was implanted as full-thickness LV wall patch replacement. At 1-week, 1-month, or 3-month intervals, pigs were terminated. After macroscopic examination, samples of tissue were prepared for histology, immunocytochemistry, and analysis of cell proportions by flow cytometry. One-week and 1-month patches were intact with thrombus and inflammation; at 1 month, there was also tissue with spindle-shaped cells in proteoglycan-rich and collagenous matrix. More alpha-smooth muscle actin-positive cells were present in urinary bladder matrix (UBM) than in ePTFE (22.2+/-3.3% versus 8.4+/-2.7%; P=0.04). At 3 months, UBM was bioresorbed, and a collagen-rich vascularized tissue with numerous myofibroblasts was present. Isolated regions of alpha-sarcomeric actin-positive, intensely alpha-smooth muscle actin-immunopositive, and striated cells were observed. ePTFE at 3 months had foreign-body response with necrosis and calcification. Flow cytometry showed similarities of cells from UBM to normal myocardium, whereas ePTFE had limited cardiomyocyte markers. CONCLUSIONS: Appearance of a fibrocellular tissue that included contractile cells accompanied biodegradation of UBM when implanted as an LV-free wall infarction patch. UBM appears superior to synthetic material for cardiac patching and trends toward myocardial replacement at 3 months.

Implications of p53 in growth arrest and apoptosis on combined treatment of human Mammary epithelial cells with topotecan and UCN-01.

We previously reported (Cancer Chemother Pharmacol 45: 252-258, 2000) that UCN-01 (7-hydroxystaurosporine), a protein kinase inhibitor, which is under clinical trials as an anti-cancer agent in the USA and Japan, enhanced camptothecin-induced cytotoxicity in breast cancer cells that lack p53 function. This enhancement was mediated by the abrogation of G2 arrest of tumor cells. Subsequent studies from our laboratory also revealed that the combined use of both UCN-01 and camptothecin induced DNA double strand breaks in p53 mutant tumor cells but not in normal or p53 negative epithelial cells. In this study, we report the implication of p53 on growth arrest and apoptosis following the combined treatment of human mammary epithelial cells with topotecan, a specific topoisomerase I inhibitor, and UCN-01. Experiments were performed on the following cells: normal human mammary epithelial cells (HMEC) with wild type p53, HME cells transfected with HPV16 E6 protein which inactivates p53 (HMEC/E6), and MDA231 mammary tumor cells with p53 mutation. UCN-01 selectively enhanced the cytotoxicity of topotecan in both MDA231 and HMEC/E6 cells. In contrast, UCN-01 showed little pharmacological effect, if any, on HME cells. Median-effect analysis indicated that a synergistic cytotoxic interaction existed between UCN-01 and topotecan in both MDA231 and HMEC/E6 cells, whereas, in the normal HME cells, the growth inhibition was only additive. Detailed cell-cycle analyses revealed that UCN-01 abrogated S-phase accumulation induced by topotecan treatment in p53 defective MDA231 tumor cells and HMEC/E6 cells. No changes in the cell cycle profiles of the normal HME cells were observed. In combination, UCN-01 and topotecan induced maximum apoptotic response on both HMEC/E6 and MDA231 cells at 6 and 48 hrs, respectively. These data indicate that UCN-01 selectively enhances topotecan cytotoxicity in p53 defective cells through the induction of apoptotic signaling pathway(s), although the time course for the induction of cell death is not the same. UCN-01 may, therefore, provide a new modality for topotecan-based therapy, particularly in p53 defective cancer patients.

Resveratrol is a potent inducer of apoptosis in human melanoma cells.

Resveratrol is a plant polyphenol found in grapes and red wine. It has been found to have beneficial effects on the cardiovascular system. Resveratrol also inhibits the growth of various tumor cell lines in vitro and inhibits carcinogenesis in vivo. In this study we examined the effect of resveratrol on growth of two human melanoma cell lines. We found that this plant polyphenol inhibited growth and induced apoptosis in both cell lines, with the amelanotic cell line A375 being more sensitive. The potential involvement of different MAP kinases in the action of resveratrol was also examined. Although resveratrol did not alter the phosphorylation of p38 or JNK MAP kinases in either cell line, it induced phosphorylation of ERK1/2 in A375, but not in SK-mel28 cells. These results suggest that in vivo studies of the effect of resveratrol on melanoma are warranted and that this plant polyphenol might have effectiveness as either a therapeutic or chemopreventive agent against melanoma.