Low dosage 5-fluorouracil increases the transfection efficiency of Ad/VEGF-A in mouse lung carcinoma cell line LA795 and inhibits tumor growth.

BACKGROUND AND OBJECTIVE: Adenovirus vectors were widely used in gene therapy for tumors. We used adenovirus vector to transfer small interfering RNA (siRNA) against vascular epithelium growth factor A (VEGF-A) molecules to mouse lung adenoma LA795 cells and used low dose of chemotherapeutic drugs to further elevate the infection efficiency of adenovirus vector in and therapeutic effect of RNAi on tumor cells. METHODS: LA795 cells were infected by Ad/EGFP and treated with different dosages of gemcitabin, epirubicin, cisplatin, or 5-fluorouracil (5-FU). Cells were observed under fluorescence microscope continuously using green fluorescent protein (GFP) as the reporter gene. The percentage of GFP-positive cells and fluorescent intensity were tested by flow cytometry to determine optimum concentrations of drugs. Ad/siVEGF-A containing VEGF-A siRNA was constructed. Real-time PCR and ELISA were applied to measure the expression level of VEGF-A after LA795 cells were infected by Ad/siVEGF-A and treated with 5-FU. The combination of Ad/siVEGF-A and 5-FU was also applied in treating subcutaneous tumor in mice. RESULTS: Low dose of 5-FU elevated the Ad/EGFP infection in LA795 cells significantly, and also enhanced the effect of Ad/siVEGF-A in down-regulating VEGF-A mRNA and protein levels in tumor cells. When used in tumor in vivo, the combination strategy repressed tumor growth effectively. CONCLUSION: Low dose of 5-FU can enhance the capability of adenovirus infecting tumor cells and promote the efficiency of gene therapy by adenovirus.

[An analysis of leukocyte subsets chimerism following allogeneic peripheral blood stem cell transplantation].

OBJECTIVE: To analyse the relationship of T lymphocyte and granulocyte chimerism following allogeneic peripheral blood cell transplantation and the occurrence of relapse, graft failure and graft versus host disease. METHODS: 21 patients underwent allogeneic peripheral blood stem cell transplantation (allo-PBSCT). Fluorescence-activated cell sorter (FACS) sorted CD3+ T lymphocytes and CD15+ granulocyte from peripheral blood of all the patients were analyzed for short tandem repeats in 7 days interval for 1 month starting from the day of PBSCT, then 1 month interval for 6 months, and then 3 months interval to the end of one year. RESULTS: Chimerism of granulocyte was higher than T lymphocyte on day 7 posttransplant in 4 patients given myeloablative conditioning. The median donor chimerism of granulocyte and T lymphocyte was 95% and 55% respectively. The other 17 patients had higher chimerism of T lymphocyte than granulocyte on day 7, which was 60% (15%-76%) and 0% (0%-40%) respectively. 20 patients reached complete donor chimerism (CDC) on day 21 (14-102 days) for T lymphocyte and on day 14 for granulocyte, except one relapsed on day 28. Seven patients had decreasing mixed chimerism when disease relapsed or graft failure occurred. T cell donor chimerism decreased earlier than myeloid cells, however, bone marrow sample and granulocyte still remained in complete donor chimerism or stable mixed chimerism, bone marrow smear showed normal at the same time. CONCLUSION: Blood leukocyte subset chimerism analysis, especially T cell chimerism analysis may provide earlier information of engraftment, relapse and graft failure than blood and bone marrow samples, therefore immunomodulatory therapies may be given to recipients earlier and overall survival may be improved.

Chimerism status is correlated to acute graft-versus-host disease after allogeneic stem cell transplantation.

To evaluate the correlation between chimerism status and acute graft-versus-host disease (aGVHD) following allogeneic hematopoietic stem cell transplantation. Chimerism of peripheral blood of 124 patients was monitored at regular intervals post-transplant. The chimerism of 124 post-transplant cases of CD3(+)T lymphocytes, 107 cases of CD3(-)CD56(+)CD16(+)NK lymphocytes, 49 cases of CD15(+) granulocytes, and 27 cases of CD19(+)B lymphocytes sorted by fluorescence-activated cell sorter were analyzed by polymerase chain reaction amplification of short tandem repeats. Differences were found in the time between establishment of full donor T-cell chimerism and the occurrence of aGVHD (P = 0.035, two related samples test). Patients with ≥69 % donor chimerism on day +7 in T-cells had higher rates of aGVHD. This study may provide a rational basis for treatment with adoptive immunotherapy at an earlier time, such as day 7 after SCT, than at present to prevent aGVHD.

[Inhibitory effect of Rnai on AML1 -ETO fusion gene expression in leukemia cells].

OBJECTIVE: By inhibiting AML1 -ETO fusion gene expression in Kasumi-1 cells with RNAi, to investigate the changes in cell proliferation and cell cycle. METHODS: The small interference RNAs (siRNAs) specifically targeting the AML1 -ETO fusion gene were synthesized in vitro and transfected into Kasumi-1 cells by electroporation, the non-specific siRNAs transfected cells were taken as control. EGFP plasmid was transfected into Kasumi-1 cell and the transfection efficiency was detected by FCM. Inhibitory effect of siRNAs were detected by real-time RT-PCR and Western blots. Cell proliferation was measured by CCK-8 assay. DNA content was detected by PI assay. RESULTS: The transfection efficiency was 44.5%. The AML1 -ETO specific siRNAs inhibited AML1 -ETO expression at both mRNA and protein levels. The cell proliferation rate in siRNAs treated group was lower than that in control group 72 h after transfection [(47.90 +/- 0.02)% vs (66.90 +/- 0.08)% , P < 0.05]. The cell cycle was blocked at G1 phase 72 h after siRNAs treatment, the cell proportion in G1 phase being 38.3% and 31.6% in control group, while in G2/M phase being 1.8% and 2.4% respectively. CONCLUSIONS: The synthesized siRNAs can inhibit AML1 -ETO fusion gene expression. AML1 -ETO specific siRNA induced the decline of AML1 -ETO fusion protein in Kasumi-1 cell, and then caused the cell cycle blocked in G1 stage and eventually inhibited the cell proliferation.

[Distribution of abnormal cell clone with deletion of chromosome 20q in marrow cell lineages and apoptosis cells in myelodysplastic syndrome].

This study was aimed to investigate the distribution of abnormal clone in marrow cell lineages and apoptosis cells in myelodysplastic syndrome (MDS) with deletion of chromosome 20q. Monoclonal antibodies recognizing myeloid precursors (CD15), erythroid precursors (GPA), T cells (CD3(+)CD56(-)CD16(-)), B cells (CD19), NK cells (CD3(-)CD56(+)CD16(+)) were used to sort bone marrow cells in a MDS patient with del (20q) by fluorescence activated cell sorting (FACS). Annexin V-FITC and PI were used to sort bone marrow Annexin V(+)PI(-) and Annexin V(-)PI(-) cells by FACS. The sorted positive cells were detected by interphase dual-color fluorescence in situ hybridization (D-FISH) using a LSI D20S108 probe (Spectrum Orange) and a Telvysion TM 20p probe (Spectrum Green). FACS and FISH analysis were also performed on the samples from 4 cases with normal karyotype. The results showed that the proportions of MDS clone in the myeloid and erythroid precursors were 70.50% and 93.33% respectively, in the RAEB-1 patient with del (20q) and were obviously higher than that in control group (5.39% and 6.17%). The proportions of abnormal clone in T, B and NK cells were 3.23%, 4.32% and 5.77% respectively and were less than that in control group (5.76%, 4.85%, 6.36%). The percentage of apoptotic cells in the bone marrow nucleated cells was 16.09%. The proportions of MDS clone in Annexin V(+)PI(-) and Annexin V(-)PI(-) cells were 32.48% and 70.11%, respectively. It is concluded that most myeloid and erythroid precursors are originated from the abnormal clone in MDS with del (20q). A little part of apoptotic cells are derived from the abnormal clone.

[Clinical significance of dynamic monitoring of cell chimerism following allogeneic hematopoietic stem cell transplantation].

OBJECTIVE: To evaluate the relationship of chimerism status of cell subsets with engraftment, occurrence of acute graft versus host disease (aGVHD), graft rejection and disease relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: Chimerism status in peripheral blood (PB) and bone marrow (BM) of 65 patients received allo-HSCT were monitored at regular intervals post-transplant. Fluorescence-activated cell sorter (FACS) was used to sort CD3(+)T lymphocytes in 65 cases, CD3(-)CD56(+)CD16(+)NK cells in 52 cases, CD15(+) granulocytes in 32 cases and CD19(+)B lymphocytes in 20 cases post transplants. The chimerism status of different lineage cells was analyzed by polymerase chain reaction amplification of short tandem repeats (PCR-STR). RESULTS: On day +7, NK-cells donor chimerism (DC 55.5%) was higher than other cell subsets. T lymphocyte was the latest one to reach complete donor chimerism (CDC) with a median on day +21. Patients whose T lymphocytes donor chimerism was more than 70% on day +7 and more than 95% on day +14 had a high risk for acute aGVHD. In all cases except those with ALL, the decreased DC of T lymphocytes were observed before molecular or hematological relapse occurred. CONCLUSION: Serial and quantitative T cell chimerism analysis provides a reliable and rapid screening method for the early detection of engraftment, graft rejection, disease relapse and occurrence of aGVHD, therefore, is a prognostic tool to identify patients at high risk of aGVHD and disease relapse following allo-HSCT.

[Evaluation of the subsets of lymphocytes and their activated status in patients with myelodysplastic syndrome].

This study was purposed to investigate the clinical significance of the amount and activated status of T cell subsets, B cells, NK cells in peripheral blood from patients with myelodysplastic syndrome (MDS). The proportion of T cells, B cells, NK cells in peripheral blood from 30 patients with MDS and their surface activation markers of CD28, CD45RA, CD45RO, CD69, HLA-DR were analyzed by flow cytometry. Twenty-two patients were in the low risk group (RA + RAS) while eight patients were in the high risk group (RAEB + RAEBT). The result showed that the amounts of T cells (CD3+ cells) in peripheral blood from patients with MDS were lower than those in control group. The amounts of naive CD4+ cells (CD4+ CD45RA+ cells) in MDS patients were lower than those in control. The expression rates of early activation marker (CD69) and late activation marker (HLA-DR) on CD3+ cells in MDS patients were significantly higher than those in control. The abnormalities of the immunologically competent cells were mainly observed in the low risk group (RA + RAS), and were characterized by the high expression rates of CD69+ and HLA-DR+ on CD3+ cells, the decrease of B cell amounts. The amount abnormalities of T cell subsets were mainly observed in high risk group (RAEB + RAEBT), and were characterized by the decrease of CD3+ cells and CD3+ CD4+ CD8- cells (Th cells) amounts without high expression of the CD69 and HLA-DR, the decrease of NK cells amounts. It is concluded that there are the abnormalities of T cell subsets and function in the patients with MDS and may change with disease progression, so the measurement of amount and activated status of T cell subsets in peripheral blood from MDS patients can have predictive role for diagnosis of disease progression and guide of therapy.