Oil A induces apoptosis of pancreatic cancer cells via caspase activation, redistribution of cell cycle and GADD expression

AIM: To explore the mechanisms of effects of oil A on apoptosis of human pancreatic cancer cells.METHODS: Cellular DNA content was analyzed by flow cytometry. Western blotting was used for caspase-3 and PARP, caspase-7, caspase-9, cytochrome c, Bcl-2, Bax, Mcl-1, cyclinA, cyclin B1, cyclin D1, cyclin E, CDK2, CDK4, CDK6,P21, P27,GADD45, GADD153.RESULTS: The caspase-3, caspase-7, and caspase-9activities were significantly increased as well as the cleavage of caspase-3, downstream substrate poly-ADP ribose polymerase (PARP) was induced. The amount of cytochrome c in the cytosolic fraction was increased, while the amount of cytochrome c in the mitochondrial fraction was decreased after oil A treatment. The anti-apoptosis proteins Bcl-2and Mci-1 were decreased in parallel and Bax increased,indicating that Bcl-2 family proteins-mitochondria-caspase cascade was responsible for oil-induced apoptosis. The proportion of cells in the G0/G1 decreased in MiaPaCa-2and AsPC-1 cells after the treatment of oil A for 24 hours.The number of cells in S phase was increased in two cancer cell lines at 24 hours. Therefore, cells were significantly accumulated in G2/M phase. The cells with a sub-G0/G1DNA content, a hallmark of apoptosis, were seen at 24 hours both in MiaPaCa-2 and AsPC-1 cells following exposure to oil A. The expression of cyclin A and cyclin B1 was slightly decreased and cyclin D1 levels were markedly lowered in MiaPaCa-2 cells. The expression of cyclin A and cyclin B1 was markedly decreased and cyclin D1 levels were slightly lowered in AsPC-1 cells, while cydin E was not affected and the levels of CDK2, CDK4, and CDK6 were unchanged in MiaPaCa-2 and AsPC-1 cells. In response to oil A, P21 expression was increased, but P27 expression was not affected. The expression of both GADD45 and GADD153was increased in two cell lines following oil A treatment.CONCLUSION: Oil A induces apoptosis of pancreatic cancer cells via activating caspase cascade, modifying cell cycle progress and changing cell cycle-regulating proteins and GADD expression.

Inducible nitric oxide synthase expression is related to angiogenesis,bcl—2 and cell proliferation in hepatocellular carcinoma

In this study, we examined the expression of inducible nitric oxide s ynthase (iNOS) and vascular endothelial growth factor (VEGF) by immunohistoc hemi cal staining in 76 tissue sections collected from hepatocellular carcinoma (HCC) patients undergoing hepatectomy. Microvascular density (MVD) was determined by counting endothelial cells immunostained using anti-CD34 antibody. We performe d DNA-flow cytometric analyses to elucidate the impact of iNOS and VEGF expressi o n on the cell cycle of HCC. Most of the HCC cells that invaded stroma were mark edly immunostained by iNOS antibody. The iNOS stain intensity of the liver tissu e close to the tumor edge was stronger than that of HCC tissue, and the stronges t was the hepatocytes closer to the tumor tissue. However, iNOS expression in 10 normal hepatic samples was undetectable. VEGF positive expression ratio was 84. 8% in iNOS positive expression cases, and the ratio was 35.3% in negative cases. There was significant correlation (P=0.000) between iNOS and VEGF expressi on. Moreover, iNOS expression was significantly associated with bcl-2 and MVD, but w ithout p53 expression. DNA-flow cytometric analyses showed that combined expres s ion of iNOS and VEGF had significant impact on the cell cycle in HCC. PI (Proli ferating Index) and SPF (S-phase fraction) in the combined positive expression o f iNOS and VEGF group was significantly higher than that in the combined negativ e group. The present findings suggested that iNOS expression was significantly a ssociated with angiogenesis, bcl-2 and cell proliferation of HCC.

CLINICAL SIGNIFICANCE OF THE DETECTION OF MINIMAL RESIDUAL DISEASE IN CHILDHOOD B-ALL BY FLOW CYTOMETRY

Objective To detect the minimal residual disease in children with B-ALL and to evaluate its clinical significance by flow cytometry. Methods 58 childhood B-ALL cases were enrolled into this study and 33 MRD analyses were performed after remission induction therapy.Four-color combinations of fluorochrome labeled monoclonal antibodies against lymphocyte lineage related phenotypes were used to analyze leukemic cells with flow cytometry.The cells from normal bone marrow were used as controls.The combinations of phenotypes that reflect the antigen expression differences between leukemic and normal bone marrow cells on flow cytometry were considered to be the effective phenotype combinations in the first step screening.The effective phenotype combinations were then used to monitor MRD during the disease course after therapy began. Results 58 cases of childhood B-ALL were screened for MRD effective phenotype combinations.The effective phenotype combinations were identified in 89.7% of B-ALL cases in this study.Four-color phenotype combinations were composed of CD10/CD34/CD19 plus another effective marker such as CD38,CD58,CD66c,CD21.The senstitivity of this method was 0.01%,much higher than that of microscopic inspection.In 8 cases,their bone marrow microscopic inspection results showed no remaining leukemic cells;but with flow cytometry,the percentage of leukemic cells were 5.66%,0.36%,1.43%,0.069%,1.55%,2.7%,0.028% and 0.015%,respectively.In risk stratification,all these MRD positive cases were classified into high risk group for relapse and 1 case showed early relapse within 6 months. Conclusion The application of flow cytometry in MRD measurement can significantly improve the sensitivity of detection of remained leukemic cells in childhood B-ALL,and can provide more accurate information on disease progression as well as the efficacy of therapy,thus facilitate future treatment decisions and follow ups.