| Objectives (1) To investigate the mechanism and the therapy of leukemia infiltration, we established a highly invasive human mono-histiocytic leukemia cell line, U937-HI, a subclone of U937 cell line which was originated from mono-histiocytic leukemia, and compare the biology characteristics between U937-HI and its parent cell line U937. (2) The difference of NF-B, VEGF, MMP-1 and MMP-9 expression between U937-HI and U937 cell line were explored. Cytosine arabinoside (Ara-C) and dexamethasone as NF-KB activator and suppressor respectively, the impact of NF-KB on VEGF, MMP-1 and MMP-9 was also studied.Methods High invasive cell line U937-HI derived from U937 cells was established by repeated passage in nude mice in vivo and in vitro. The biological characteristics of U937-HI was compared with U937, in respect of morphology, immunohistochemistry, cell growth curve, colony formation percentage in soft agar, cell growth cycle by flow cytometer. The changes of karyotype were also studied.The experimental animals were divided into experimental arm and control arm. U937-HI and U937 cells were inoculated in the abdominal cavity of nude mice at 5 X I06/0.2ml, respectively. All mice were sacrificed after three weeks. The infiltration capacities of the two cell lines were compared by micro- and macro- pathology.NF-KB, VEGF, MMP-1 and MMP-9 expression of U937-HI and U937 cell line were studied by way of Western blot. Their change after incuborate with Ara-C and dexamethasone also was studied.Results Cell line U937-HI was establish by repeated passage in nude mice. There was no significant difference of cell morphology, cell growth curve and proliferation time between U937-HI and its parent cell line. The ultrastructure of U937-HI exhibit several features, such as the nuclear abnormalities, the increase of autosome, and allosome rare, to name a few. The colony formation percentage of U937- HI is higher than its parent cell line U937. The cell cycle analysis by flow cytometer showed the percentage of U937-HI in S phase was higher than that of U-937. The results of immunohistochemistry of the two cell lines were consistentmono-histiocytic cells, that is, POX negative, PAS dotted positive, NSE positive and can be suppressed by NaF. CD2, CD3, CD14 and CD19 were negative, CD13,CD45 were positive on the surface of U937-HI cells. The cytogenetic analysis showed the chromosome numbers of U937-HI cells varied from 54 to 59, the karyotype of stem line was hyperdiploid. Chromosomes model was 56+0.99. And the chromosome numbers of U937 cells varied from 53 to 57, the karyotype of stem line was hyperdiploid. Chromosomes model was 55 + 0.82. The karyotype related to infiltration had not detected.The mean time to the advent of ascites was days in experimental arms. A amout of monocyte leukemia cell could be seen on ascites smear. No ascites was detected in controlled arm. Apart from mesentery, liver, spleen, kidney and lung also had been infiltrated by U937-HI cells. In control arm, U937 cells mainly infiltrated the mesentery. The weight of guts in two arms had statistical difference. In experiment arm, the weight of live, spleen and kidneys are (2.526 0.075)g, (0.478 0.054)g, (0.513 + 0.054)g, respectively, whereas, (2.404 0.003)g, (0.394+0.012)g, (0.426+0.008)g in control arm (P<0.01). The weight of guts in two arms had statistical difference.By means of Western blot, the expression of NF-B, VEGF, MMP-1 and MMP-9 of U937-HI cell line was higher than that of U937 cell line. After incubation with Ara-C for 3 hours at the concentration of lumol/L, the expression of NF-B VEGF MMP-1 and MMP-9 of U937-HI cell line was increased, whereas incubation with dexamethasone lumol/L for 8 hours, the expression of NF-B, VEGF, MMP-1 and MMP-9 was decreased. Incubation with lumol/L dexamethasone for 8 hours and lumol/L Ara-C for 3 hours in row, the expression of NF-KB, VEGF, MMP-1, MMP-9 was between that of disposal with Ara-C and dexamethasone separately.Conclusions l.The highly invasive human mono-histiocytic leukemia cell line U937-HI was...
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