Efficacy of Decitabine Combined with Pre-Excitation Chemotherapy in the Treatment of Middle-Aged and Elderly MDS Transformed Acute Myeloid Leukemia / 中国实验血液学杂志

OBJECTIVE@#To investigate the efficacy of domestic decitabine (D) combined with pre-excitation chemotherapy consisted of Ara-c, THP and G-CSF(CTG) in treatment of middle-aged and elderly patients with MDS-transformed AML and prognosis-related factors.@*METHODS@#Seventy-six patients with MDS-transformed AML treated in our hospital from June 2013 to June 2015 were selected according to treatment regimens, 76 patients were divided into 2 groups: CTG group(36 cases) and D+CTG group(40 cases). The patients in CTG group received treatment with Ara-C, THP and G-CSF; the patients received the treatment with decitabine plus CTG. The patients in 2 groups all received 4 course treatment, then received maintaining treatment. The therapeutic efficacy and incidence of adverse reactions in 2 group were compared, at the same time, the risk factors affecting the prognos of patients treated with D+CTG were analyzed.@*RESULTS@#There were no siginificant differences in age, sex, initial blood cell count, bone marrow blast ratio, disease types, chromosome karyotypes and FLT3-ITD gene mutation between 2 groups. The efficacy analysis showed that the efficacy of D+CTG was superior to CTG, ORR in D+CTG group was significantly higher than that in CTG group (72、52 vs 50%) (P0.05). The follow-np for 2 years showed that the median survival time in D+CTG group was significantly longer than that in CTG group (19.9 vs 11.0 months) (P<0.05). The multivariate analysis showed that the 1 course efficacy (RR=3.926, P=0.015) and FLT3-ITD gene mutation (RR=4.347, P=0.004) were independent risk factors affecting the efficacy of D+CTG treatment.@*CONCLUSION@#The short-and long-term efficacy of domestic decitasine combined with preexcitation chenotherapy in treatment of middec-aged and eldery patients with MDS transformed AML is superior to single pre-excitation chenothrapy, moreover the incidence of adverse reactions did not increase. The 1 course efficacy and FLT-3 ITD gene mutation are the independent risk factors affecting the prognosis of patients. .

Killing effect of double suicide genes mediated by retroviral vector on k562 cells / 中国实验血液学杂志

The aim of study was to investigate the killing effect of double suicide gene system mediated by retroviral vector on K562 cells in vivo and ex vivo. CDglyTK gene was transfected into PA317 cells by using lipofectamine. K562 cells were infected with viral supernatant. K562/CDglyTK cells were treated with 5-fluorocytosine (5-FC) and/or ganciclovir (GCV). Mice were randomly divided into three groups: tumor formation, tumor inhibition and tumor therapy. Each mouse was implanted with K562/CDglyTK cells or K562 cells. The results indicated that the killing effect of 5-FC in combination with GCV on K562/CDglyTK was more significant than using 5-FC or GCV alone. In vivo study showed that after being injected subcutaneously with K562 cells and K562/CDglyTK cells, there was not obvious difference in tumor formation rate of mice, 5-FC + GCV could suppress tumor formation of the K562/CDglyTK cells. After being treated with 5-FC and GCV, the median tumor volume of mice implanted with K562/CDglyTK cells decreased obviously, compared with the control group. Their median survival was significantly prolonged. It is concluded that double suicide genes are more effective for killing effect on K562 cells in vivo and in ex vivo. It may be applicable to clinical gene therapy.

Application of pseudotyped lentivirus-mediated double suicide genes to allogeneic bone marrow transplantation in mice / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the feasibility and efficiency of cytosine deaminase (CD)/thymidine kinase (TK) gene-modified donor T cells used in allogeneic bone marrow transplantation (allo-BMT) as an approach to mitigate GVHD without compromising engraftment.</p><p><b>METHODS</b>The pseudotyped lentivirus vectors containing CD and TK double suicide genes were transfected with lipofectine to donor T cells. Lethally irradiated 615 leukemia mice were transplanted with BALB/c bone marrow plus CD(+)TK(+)T cells. GVHD prophylaxis was by administration of ganciclovir (GCV) and 5-Fluoride cytosine (5-FC).</p><p><b>RESULTS</b>The pseudotyped lentivirus-mediated gene transfer system could efficiently transfer CD and TK double suicide genes into donor T cells. Administration of GCV and 5-FC to the mice could markedly potentiate the CFU-S and CFU-GM yields and raise the number of peripheral white blood cells. 1 x 10(7) CD(+)TK(+) allogeneic T cells caused GVHD of a similar magnitude and time course to that of fresh, naive T cells after allo-BMT. Administration of GCV and 5-FC in mice received CD(+)TK(+)T cells reduced the severity of GVHD and resulted in significantly longer survival as compared with non-administration mice, and the effect was stronger than that of administration of GCV or 5-FC alone.</p><p><b>CONCLUSION</b>Administration of CD + TK gene-modified donor T cells to recipient in allo-BMT might be an approach to mitigate GVHD without compromising alloengraftment.</p>

Establishment of lentivirus-mediated system of double suicide genes and its killing effects on K562 cells / 中国实验血液学杂志

To establish lentivirus-mediated system of double suicide genes and explore its killing effects on K562 cells, lentivirus transfer vector for double suicide genes was constructed using molecular methods, three plasmids of lentivirus gene transfer vector system were transferred into packaging cell line 293T using lipofectine method, the transfer effect was observed through fluorescence microscopy, the lentivirus particles were observed by means of electron microscopy. High titer of lentivirus was harvested from the supernatant of virus-producing cell culture and concentrated by high-speed centrifugation with Poly-L-Lysine (PLL). The K562 cells were infected with the concentrated supernatant containing the virus with the double suicide genes. Fluorescence microscopy and RT- PCR confirmed the integration and expression of extraneous gene. The cytotoxicity to these transgenic cells treated with 5-FC and GCV was measured by MTT assays. The growth inhibition ratio (GIR) of cells and inhibition concentration 50 (IC(50)) were counted. After administration of GCV and 5-FC, the changes of those cells were observed through scanning electron microscope. The results showed that lentivirus transfer vector with double suicide genes was constructed successfully. The above-mentioned plasmids were effectively transferred into 293T cells. So much green fluorescence was observed through fluorescence microscope. A lot of lentivirus particles were observed through transmission electron microscope. Double suicide genes mediated by lentivirus were stably integrated and expressed in K562 cells after infection with the concentrated virus using fluorescence microscopy and RT-PCR. The GIR of K562 cells using GCV or 5-FC was 48.73% or 50.69% respectively and it was apparently higher than that of untransfected cells (P < 0.01). When using GCV and 5-FC together, the GIR was 87.69%, which was apparently higher than that of group using GCV or 5-FC alone (P < 0.01). In conclusion, lentivirus-mediated gene transfer system could transfer CD and TK double suicide genes into K562 cells with high efficiency and it had strong killing effects when giving 5-FC and/or GCV. The cytotoxic effects of double suicide genes were superior to that of single suicide gene. The lentivirus-mediated double suicide gene transfer system is a high-efficiency gene transfer vector.