Targeting GLI1 Suppresses Cell Growth and Enhances Chemosensitivity in CD34+ Enriched Acute Myeloid Leukemia Progenitor Cells.

BACKGROUND/AIMS: Resistance of leukemia stem cells (LSCs) to chemotherapy in patients with acute myeloid leukemia (AML) causes relapse of disease. Hedgehog (Hh) signaling plays a critical role in the maintenance and differentiation of cancer stem cells. Yet its role in AML remains controversial. The purpose of the present study is to investigate the role of GLI1, the transcriptional activator of Hh signaling, in AML progenitor cells and to explore the anti-AML effects of GLI small-molecule inhibitor GANT61. METHODS: The expression of GLI1 mRNA and protein were examined in AML progenitor cells and normal cells. The proliferation, colony formation, apoptosis and differentiation of AML progenitor cells were also analyzed in the presence of GANT61. RESULTS: Kasumi-1 and KG1a cells, containing more CD34+ cells, expressed higher level of GLI1 compared to U937 and NB4 cells with fewer CD34+ cells. Consistently, a positive correlation between the protein levels of GLI1 and CD34 was validated in the bone marrow mononuclear cells (BMMC) of AML patients tested. GANT61 inhibited the proliferation and colony formation in AML cell lines. Importantly, GANT61 induced apoptosis in CD34+ enriched Kasumi-1 and KG1a cells, whereas it induced differentiation in U937 and NB4 cells. Furthermore, GANT61 enhanced the cytotoxicity of cytarabine (Ara-c) in primary CD34+ AML cells, indicating that inhibition of GLI1 could be a promising strategy to enhance chemosensitivity. CONCLUSIONS: The present findings suggested that Hh signaling was activated in AML progenitor cells. GLI1 acted as a potential target for AML therapy.

Apatinib (YN968D1) enhances the efficacy of conventional chemotherapeutical drugs in side population cells and ABCB1-overexpressing leukemia cells.

P-glycoprotein (P-gp, ABCB1) overexpression and enrichment of stem-like cells are linked to poor prognosis in tumor patients. In this study, we investigated the effect of apatinib, an oral multi-targeted tyrosine kinase inhibitor (TKI) on enhancing the efficacy of conventional anticancer drugs in side population (SP) cells and ABCB1-overexpressing leukemia cells in vitro, in vivo and ex vivo. Our results showed that apatinib significantly enhanced the cytotoxicity and cell apoptosis induced by doxorubicin in SP cells sorted from K562 cells. Furthermore, apatinib also strongly reversed multidrug resistance (MDR) in K562/ADR cells, and the primary leukemia blasts overexpressing ABCB1 while showed no synergistic interactions with chemotherapeutic agents in MRP1-, MRP4-, MRP7- and LRP-overexpressing cells. Apatinib treatment markedly increased the intracellular accumulation of doxorubicin and rhodamine 123 in K562/ADR cells and the accumulation of rhodamine 123 in the primary leukemia blasts with ABCB1 overexpression. Apatinib stimulated the ATPase activity of P-gp in a dose-dependent manner but did not alter the expression of ABCB1 at both mRNA and protein levels. The phosphorylation level of AKT and ERK1/2 remained unchanged after apatinib treatment in both sensitive and MDR cells. Importantly, apatinib significantly enhanced the antitumor activity of doxorubicin in nude mice bearing K562/ADR xenografts. Taken together, our results suggest that apatinib could target to SP cells and ABCB1-overexpressing leukemia cells to enhance the efficacy of chemotherapeutic drugs. These findings should be useful for the combination of apatinib and chemotherapeutic agents in the clinic.

Prognostic value of the multidrug resistance transporter ABCG2 gene polymorphisms in Chinese patients with de novo acute leukaemia.

BACKGROUND: Functional polymorphisms of the ABCG2 gene may contribute to individual variability in drug response and the prognosis of patients. METHODS: In the present study, the genetic polymorphisms and expression of ABCG2 were analysed in blasts cells obtained from 184 Chinese patients with de novo acute leukaemia to investigate their possible association with clinical outcomes. RESULTS: A novel synonymous ABCG2-single nucleotide polymorphism (SNP) at exon 16 (13561218 C/T) and five known SNPs at exon 2 (13608835 G/A), exon 5 (13600044 C/A), intron 10 (13576005 C/T), intron 13 (13564503 C/T) and intron 14 (13563578 A/G) were identified with occurrence rates of 1.1%, 64.1%, 30.4%, 21.2%, 39.7% and 28.8%, respectively. We found that patients with the ABCG2 34GG genotype displayed longer disease free survival (DFS) (P<0.001) and overall survival (OS) (P<0.001) than those with the 34GA/AA genotypes. Furthermore, the DFS and OS were significantly diminished in bone marrow transplantation (BMT) patients with the 34GA/AA genotypes relative to those with the 34GG genotype. CONCLUSIONS: These results suggest that these highly prevalent ABCG2 34GA/AA genotypes are associated with poor prognosis of Chinese patients with acute leukaemia and BMT patients.

[Inhibitory effect of apatinib on HL-60 cell proliferation and its mechanism].

OBJECTIVE: To investigate the effect of apatinib, a small-molecule vascular endothelial growth factor receptor-2 tyrosine kinase inhibitor, on the proliferation of human acute myeloid leukemia HL-60 cells and explore the possible mechanism. METHODS: MTT assay was used to assess the cytotoxicity of apatinib in HL-60 cells. The apoptosis and cell cycle changes of the cells in response to apatinib treatment were analyzed by flow cytometry, and Western blotting was used to assay P-Akt and P-Erk1/2 expressions in the cells. RESULTS: Apatinib significantly inhibited the proliferation of HL-60 cells in vitro with an IC(50) of 4.96∓0.32 µmol/L. Apatinib treatment significantly increased the apoptotic rate of the cells in a dose-dependent manner, but produced no significant effect on the cell cycle (P>0.05). Western blotting showed that the expressions of P-Akt and P-Erk1/2 decreased in HL-60 cells after a 48-h apatinib treatment. CONCLUSION: Apatinib inhibits the proliferation of HL-60 cells by inducing cell apoptosis probably through the mechanism of inhibiting the expressions of the Akt/Erk1/2 signal transduction pathway.

Up-regulation of ABCB1/P-glycoprotein by escaping promoter hypermethylation indicates poor prognosis in hematologic malignancy patients with and without bone marrow transplantation.

We investigated the correlation between MDR1 promoter methylation status and MDR1 expression in 228 hematologic malignancies patients and 90 healthy controls. High level of MDR1 mRNA correlated to promoter hypomethylation and strongly associated with poor prognosis indicated by 2-year survival rates, poor CR rate (without BMT) and high relapse rate (with BMT). Furthermore, relative luciferase activity of methylated MDR1 at promoter -50 region was significantly higher than that of the unmethylated. In addition, MDR1 in K562 cells elevated significantly after 5-Aza-dC treatment. In summary, MDR1 promoter hypomethylation conferred its up-regulation and indicated poor prognosis in patients with and without BMT.

Sensitization of ABCG2-overexpressing cells to conventional chemotherapeutic agent by sunitinib was associated with inhibiting the function of ABCG2.

Sunitinib is an ATP-competitive multi-targeted tyrosine kinase inhibitor. In this study, we evaluated the possible interaction of sunitinib with P-glycoprotein (P-gp, ABCB1), multidrug resistance protein 1 (MRP1, ABCC1), breast cancer resistance protein (BCRP, ABCG2) and lung-resistance protein (LRP) in vitro. Our results showed that sunitinib completely reverse drug resistance mediated by ABCG2 at a non-toxic concentration of 2.5muM and has no significant reversal effect on ABCB1-, ABCC1- and LRP-mediated drug resistance, although a small synergetic effect was observed in combining sunitinib and conventional chemotherapeutic agents in ABCB1 overexpressing MCF-7/adr and parental sensitive MCF-7 cells, ABCC1 overexpressing C-A120 and parental sensitive KB-3-1 cells. Sunitinib significantly increased intracellular accumulation of rhodamine 123 and doxorubicin and remarkably inhibited the efflux of rhodamine 123 and methotrexate by ABCG2 in ABCG2-overexpressing cells, and also profoundly inhibited the transport of [(3)H]-methotrexate by ABCG2. However, sunitinib did not affect the expression of ABCG2 at mRNA or protein levels. In addition, sunitinib did not block the phosphorylation of Akt and Erk1/2 in ABCG2-overexpressing or parental sensitive cells. Overall, we conclude that sunitinib reverses ABCG2-mediated MDR through inhibiting the drug efflux function of ABCG2. These findings may be useful for cancer combinational therapy with sunitinib in the clinic.

[The clinical features, chemotherapy responses and survival of 223 patients with newly diagnosed multiple myeloma].

OBJECTIVE: To explore the proportion, clinical and laboratory features, chemotherapy responses and long term survival of different kinds of newly diagnosed multiple myeloma (MM) in China. METHODS: The clinical data of 223 cases of newly diagnosed MM patients were gathered in the First Affiliated Hospital of Sun Yat-sen University from Jan, 2000 to Seb, 2007 were retrospectively analyzed. RESULTS: The proportions of each kind of MM including IgG, IgA, light chain, IgD, IgM and biclonal MM were 48.0%, 20.6%, 25.6%, 4.0%, 0.9% and 0.9% respectively. No IgE and nonsecretory myeloma was found. The median age of onset was 58 years, of which that of the IgA type was the oldest one and the light chain type was the youngest (P = 0.004). Bone pain, renal insufficiency, and anemia were the most common symptoms which accounted for 67.7%, 61.0% and 45.3% respectively. The incidences of renal inadequacy, hypercalcemia and pathological fracture in light chain type were higher than those in IgG and IgA types. Besides, no M protein were found in serum protein electrophoresis and no elevation of total globulin. The clinical features of IgD type were similar to that of the light-chain type. The total chemotherapy efficacy rate of 89 patients who were treated with more than 3 cycles in our hospital is 61.8%, which has no difference in all types. Median overall survival of the 89 patients was 33.0 months. CONCLUSION: IgG is the most common type in MM. Bone pain, anemia, hypercalcemia and renal insufficiency are common symptoms. Immunofixation electrophoresis should be performed routinely to avoid missed diagnosis of light-chain and IgD types of MM.

[Efficacy of bortezomib combined dexamethasone in 24 patients with multiple myeloma].

BACKGROUND & OBJECTIVE: Bortezomib, a potent and reversible proteasome inhibitor, induces apoptosis of myeloma cells, resulting in durable responses in patients with multiple myeloma (MM). This study was to explore the medical effects and side effects of bortezomib combined dexamethasone in treating newly diagnosed and relapsed or refractory MM, and evaluate the safety of this regimen in the patients with renal impairment. METHODS: Twenty-four MM patients were treated with bortezomib and dexamethasone in a 21-day cycle. The patients received a median of 3 cycles (range, 1-8 cycles) of the treatment. Response to bortezomib was evaluated according to the criteria of the European Group for Blood and Marrow Transplantation (EBMT); adverse events were graded according to the National Cancer Institute Common Toxicity Criteria. RESULTS: During the follow-up with a median of 4 months, 19 (79.2%) patients responded to the treatment. The complete remission (CR) rate was significantly higher in the patients of light-chain type than in those of non-light-chain type (57.1% vs. 5.9%, P=0.014). The response rates of the patients with and without renal impairment were similar (100% vs. 70.6%, P=0.272), and the renal functions were ameliorated in the patients with renal impairment during chemotherapy. Grade III-IV adverse events, including leucocytopenia (8.3%), thrombocytopenia (33.3%), diarrhea (8.3%) and debility (4.2%), could be relieved by symptomatic treatment or delayed chemotherapy. CONCLUSIONS: The combination of bortezomib and dexamethasone shows obvious effects on MM, especially in the patients with light-chain type. The adverse events can be tolerant in most patients, and this regimen is also safe in the patients with renal impairment.

[Efficacy and toxicity of intravenous busulfan-based conditioning before allogeneic peripheral blood stem cell transplantation for leukemia].

BACKGROUND & OBJECTIVE: Busulfan (Bu) is commonly used as a component of conditioning regimens for hematopoietic stem cell transplantation. Erratic gastrointestinal absorption as a result of oral administration of Bu not only affects the efficacy, but also increases the risk of toxicity. This study was to analyze the efficacy and toxicity of intravenous Bu and cyclophosphamide (Cy) conditioning before allogeneic peripheral blood stem cell transplantation (allo-PBSCT) for leukemia. METHODS: Fifteen leukemia patients received intravenous Bu/Cy conditioning before allo-PBSCT, while 20 patients received oral Bu/Cy conditioning. The responses and adverse events of the 2 groups were assessed. RESULTS: All 15 patients in intravenous Bu/Cy group had hematopoietic engraftment. The median time of engraftment was 12 (9-15) days for neutrophils and 15 (11-24) days for platelets. Of the 15 patients, 6 (40.0%) developed acute graft-versus-host disease (aGVHD), including 4 cases of grade I-II aGVHD and 2 cases of grade III-IV aGVHD; during conditioning, 7 (46.6%) had vomiting, 1 (6.7%) had oral mucositis, 1 (6.7%) had hemorrhagic cystitis, 2 (13.3%) had hepatic damage, none developed seizure. With a median follow-up of 180 days (range, 35-420 days), 14 (93.3%) patients were alive, 1 died of severe aGVHD accompanied fungal infection of the lung and central nerve system. The occurrence rates of hepatic damage and oral mucositis were significantly lower in intravenous Bu/Cy group than in oral Bu/Cy group (13.3% vs. 60.0%, 6.7% vs. 80.0%, P<0.01). There were no significant differences in hematopoietic reconstruction, aGVHD, stomatitis, gastrointestinal reaction, and hemorrhagic cystitis between the 2 groups (P>0.05). CONCLUSION: The intravenous Bu/Cy conditioning before allo-PBSCT for leukemia has clear efficacy with low extramedullary toxicity.

[Establishment of an animal model of oral mucositis induced by conditioning regimen of haematopoietic stem cell transplantation].

OBJECTIVE: To establish a rat model of oral mucositis (OM) induced by busulfan and cyclophosphamide (BUCY) conditioning regimen of hematopoietic stem cell transplantation (HSCT). METHODS: In the model group, busulfan (6.0 mg.kg(-1).d(-1) x 4 d) and cyclophosphamide (120 mg.kg(-1).d(-1) x 2 d) were administered by intra-stomach perfusion and intraperitoneal injection, respectively. The left cheek mucosa were irritated by superficial scratching on day 6. The oral mucosal score (OMS) was assessed daily. Animals were sacrificed on day 7, 10, 13, 16 and 18. The samples of blood, bone marrow, and the oral mucosa were harvest to evaluate the clinical and histological changes. RESULTS: The incidence of oral mucositis in model group was as high as 80.00% with a survival rate of 73.33%. The initial lesion on the oral mucosa was noted on day 7 with red spot and edema, and then progressive mucositis was characterized by large areas of ulcer formation. The duration of oral mucositis was 8 to 10 days. A continuous weight loss, white blood cell count decrease and bone marrow suppression occurred in the process of oral mucositis. CONCLUSIONS: An animal model of conditioning regimen-induced oral mucositis was successfully established.

[Effects and prognostic factors of HLA-matched sibling donor allogeneic hematopoietic stem cell transplantation for chronic myelogenous leukemia].

OBJECTIVE: To retrospectively analyze the curative effects and prognostic factors of HLA-matched sibling donor allogeneic hematopoietic stem cell transplantation (allo-HSCT) for chronic myelogenous leukemia patients (CML). METHODS: Of the 35 CML patients, 26 were males and 9 were females, with a median age of 32 (12 - 50) years. 30 patients were in chronic phase of CML, 5 patients were in accelerated phase. Allo-HSCT from HLA identical siblings was performed for 35 patients, of whom 11 received bone marrow transplantation (BMT) and 24 peripheral blood stem cell transplantation (PBSCT). Conditioning regimens was TBI (total-body irradiation) + CY (CTX) protocol in 8 patients and BU/CY protocol in 27 patients. The average follow-up was 48 months (range 7 - 108 months). RESULTS: 34 (97.1%) patients were successfully engrafted. Among them, 21 patients (60.0%) had three years disease-free (DFS) survival. The overall 5-year survival (OS) was 57.1%. Two patients (5.7%) relapsed. Transplant-related mortality occurred in 12 patients. Hemorrhagic cystitis (HC) occurred in 5 patients and HVOD was observed in 1 patient. Acute graft-versus-host disease (aGVHD) occurred in 18 patients (51.4%), among them 7 patients (20.0%) were of grade III-IV. Chronic GVHD was in 17 patients (48.5%). There was no significant difference in 3-years DFS between BMT group and PBSCT group (54.5% vs. 62.5%, P > 0.05). The 3-year disease-free survival (DFS) was 42.9% in TBI/CY group and 55.6% in BU/CY group (P > 0.05). In univariate prognostic analysis model, the DFS at 3 years is 75% and 47.4% for < or =30 years patients and >30 years patients, respectively, P < 0.05. The 3-year DFS of patients with first chronic phase is higher than patients with advanced diseases (61.3% vs. 40%, P < 0. 05). The 3-year DFS in patients of grade I - II GVHD was higher than that in patients of grade III-IV GVHD (81.8% vs. 14.3%, P < 0.05). CONCLUSION: The patients who had transplantation done within 1 year after diagnosis during their first chronic phase of disease and who had low-grade GVHD have better prognosis. Those patients who had III-IV acute GVHD are prone to incorporate severe infection, which was a worse prognostic factor of allo-HSCT for chronic myelogenous leukemia.

[Preliminary report of fludarabine, mitoxantrone and dexamethasone in treating refractory or relapsed multiple myeloma].

BACKGROUND & OBJECTIVE: Multiple myeloma has low complete remission rate and high recurrence rate. Recurrence or relapse of the disease is almost inevitable for most of the patients after several cycles of combined chemotherapy. This study was designed to compare efficacy of fludarabine-based regimen (fludarabine, mitoxantrone and dexamethasone) with that of pirarubicin, vincristine and dexamethasone (VAD) on refractory or relapsed multiple myeloma, and analyze their toxicities. METHODS: Twenty-two patients who had received VAD regimen were taken as a historical control group. A total of 11 patients received FND regimen. The differences between FND group and VAD group were observed and compared. The following indexes were assessed before, during, and after treatment: the partial remission (PR) rate, total response rate, time to achieve PR, the number of patients and time of serum M-component drop to more than 50% of the pre-treatment value, the ratio of myeloma cells in bone marrow drop to less than 5% or more than 80% of pre-treatment level, and the hemoglobin level increase to more than 20 g/Lû the white blood cell and platelet count of the peripheral blood, serum calcium, creatinine, beta2-microglobin and glutamic-oxaloacetic transaminase (GPT) level, adverse events were also analyzed. RESULTS: The PR rate was significantly higher in FND group than in VAD group (45.5% vs. 22.7%, P<0.05). The median time to achieve PR was significantly longer in FND group than in VAD group (76 days vs. 68 days, P<0.05). The occurrence rates of M-component decrease and hemoglobin elevation were significantly higher in FND group than in VAD group [45.5% vs. 22.7%, and 54.5% vs. 18.2%, P<0.05]. There were no significant differences in serum calcium, creatinine and GPT level pre- and post-treatment between the 2 groups. The level of serum beta2-microglobin after treatment was significantly lower than that before treatment in FND group [(1 042.8+/-72.3) microg/L vs. (2 350.2+/-184.0) microg/L, P<0.05]. The nadir white blood cell count was significantly lower in FND group than in VAD group [(0.9+/-0.46)x10(9)/L vs. (2.09+/-0.6)x10(9)/L, P<0.05], and the occurrence rates of fever and cough was significantly higher in FND group than in VAD group (36.4% vs. 4.5%, 45.5% vs. 9.0%, P<0.05). CONCLUSIONS: Compare with VAD regimen, FND regimen may enhance the PR rate of refractory or relapsed multiple myeloma patients, but it takes longer time to achieve PR, and shows obvious bone marrow inhibition, with no significant renal or hepatic toxicity. FND regimen is effective and safe in treating refractory or relapsed multiple myeloma.

[Study of TRAIL receptors expression on the mononuclear cells from multiple myeloma patients and KM3 cells].

OBJECTIVE: To study the differential expression of four TRAIL receptors on bone marrow mononuclear cells (BMMNC) from multiple myeloma (MM) patients and myeloma cell line KM3 cells, to compare their altered expressions after chemotherapy and to explore the mechanisms by which TRAIL selectively kills tumor cells. METHODS: Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and flow cytometry were used to investigate the expression of four TRAIL receptors on BMMNCs in 23 MM patients, KM3 cells and 15 controls, and the changes of their expression pattern after chemotherapy and after incubation of KM3 cells with sub-clinical concentration of doxorubicin. RESULTS: DR4 and DR5 were highly expressed on KM3 cells with no expression of DcR1 and DcR2. Expressions of DR4 and DR5 on BMMNCs from MM patients were higher and expression of DcR1 and DcR2 were lower than that of controls (P < 0.05). The expression of DR5 on MM and KM3 cells was up-regulated after chemotherapy and exposure to doxorubicin (P < 0. 05). CONCLUSIONS: The expressions of four TRAIL receptors on myeloma cells and normal controls were different, which might account for the selective killing effect of TRAIL on MM cells. Up-regulated DR5 on KM3 cells after incubating with doxorubicin and after chemotherapy suggests the cytotoxic agents might enhance the apoptosis of MM cells.

[Efficacy of imatinib mesylate, a specific inhibitor of BCR/ABL tyrosine kinase, on chronic myeloid leukemia in blast phase].

BACKGROUND & OBJECTIVE: Chronic myeloid leukemia (CML) in blast phase is refractory with a poor prognosis. This study was to evaluate efficacy of imatinib mesylate, a specific inhibitor of BCR/ABL tyrosine kinase, on CML in blast phase. METHODS: Nineteen patients with CML in blast phase (imatinib treatment group) received induction of cytarabine-based standard chemotherapy for 2 cycles, and 400 mg/d of imatinib mesylate for 4 weeks. Patients with no remission received 600 mg/d of imatinib mesylate for another 8 weeks. Treatment of 600 mg/d of imatinib mesylate was maintained if it showed effects after 8 weeks, otherwise it would be stopped. Twenty-two patients with CML in blast phase (historical control group) received inducement of cytarabine-based chemotherapy for 2 cycles, and other regimens of consolidation or continuous induction. RESULTS: Sixteen patients of imatinib treatment group achieved no hematologic remission after induction. After treated with imatinib mesylate, 6 of 16 (38%) achieved hematologic complete remission (CHR), and major cytogenetic response; 2 of 16(13%) achieved hematologic partial remission (PHR); 1 of 16 (6%) returned to chronic phase with minor cytogenetic response. Total hematologic response rate of imatinib treatment group was 57%; 1-year survival rate was 38% (6/16). Eighteen patients of historical control group achieved no hematologic remission after inducement. After treated with other regimens, 2 (11%) achieved CHR, and 1 (6%) achieved PHR. Total hematologic response rate of historical control group was 17%; 1-year survival rate was 6%(1/18), significantly lower than that of imatinib treatment group (P< 0.05). CONCLUSIONS: Imatinib mesylate may have anti-leukemic activity, and prolong survival time of patients with CML in blast phase. But problems of tumor relapse, and drug resistance are still present.

[Expression of CD117 antigen on multiple myeloma and its significance].

BACKGROUND & OBJECTIVE: Leukocyte differentiation antigen CD117 is one of the targets that tyrosine kinase selective inhibitors work on. Whether CD117 is expressed on the cell surface, and the expression level are highly correlated with tyrosine kinase selective inhibitors. This study was designed to investigate the expression of CD117 on multiple myeloma (MM) cells, which may provide a theoretical evidence for the use of tyrosine kinase selective inhibitors in MM,meanwhile,the importance of CD117 expression on MM cells was estimated. METHODS: CD117, CD56, and CD54 were measured by three-color flow cytometry with CD45/SSC gating strategy. RESULTS: Of 48 patients with MM, 17 (35.5%) had positive CD117 expression on myeloma cells, 39 (81.2%) had positive CD56 expression, and 48 (100.0%) had positive CD54 expression. CD117 expression on myeloma cells was lower than CD56, and CD54. CD117 positive expression was positive correlated with the percentage of myeloma cells in bone marrow. CD117 positive in IgG type of MM was 64%, higher than other types such as light chain or IgA. CD117 positivity showed no significant difference in different stages (P >0.05), and in patients haven't been pretreated, or relapsed after pretreated (P >0.01). In MM patients haven't been pretreated, the reaction rate of VAD chemotherapy in CD117 positive cases was 71.4%, and showed no significant difference (P >0.05) compared with the reaction rate of 66.7% in CD117 negative cases. CONCLUSION: CD117 can be regard as the related tumor antigen of MM, and may be a valuable marker in the use of tyrosine kinase selective inhibitors, which inhibit the signal conduct to the target.

[Effects of combination therapy with all-trans retinoic acid and arsenic trioxide on acute promyelocytic leukemia].

BACKGROUND & OBJECTIVE: The mechanism of effect of arsenic trioxide on promyelocytic leukemia is different from that of all-trans retinoic acid. Arsenic trioxide exerts its action by accelerating cell apoptosis, while all-trans retinoic acid by inducing cell differentiation. However, both drugs can inhibit the transcription of tissue factor (TF) mRNA in acute promyelocytic leukemia, and decrease TF level and coagulative activity to normalize coagulopathy. The objective of the study was to observe whether combination of the two drugs could improve efficacy or in contrary accentuate adverse reactions. METHODS: Two groups of patients with acute promyelocytic leukemia were included. Twenty-two patients (17 untreated cases and 5 relapsed cases) from January 2000 to October 2001 in group I were treated only with oral retinoic acid [25 mg/(m(2)x d) in two divided doses] for less than 50 days. Nineteen cases (15 untreated cases and 4 relapsed cases) from November 2001 to June 2003) in Group II were treated with combination of arsenic trioxide and all-trans retinoic acid. 0.1% AS2O3 10 ml in 500 ml 5% glucose solution was given intravenously for 4 to 6 hours per day for 28 days. The dosage of retinoic acid in group II was the same as that in group I. RESULTS: Nineteen of 22 cases in retinoic acid-treated group (group I)(16 untreated cases and 3 relapsed cases) achieved complete remission (CR). The CR rate was 86.4%. Seventeen of 19 cases in combination therapy group (group II)(15 untreated cases and 2 relapsed cases) achieved CR. The CR rate was 89.5%. The death rates were 13.6% (3/22, 1 untreated case, 2 relapsed cases) in group I and 10.5% (2/19, 2 relapsed cases) in group II, respectively. The median time to CR was 23 days in group I and 26 days in group II, and the median time to normalization of coagulopathy was 7 days in group I and 4 days in group II. Significant differences were found between the two groups. No significant adverse reaction was observed in both groups. CONCLUSION: The CR rate and death rate were not different between the two groups. The combination therapy with AS2O3 and all-trans retinoic acid can shorten the time to CR and normalization of coagulopathy.

[Comparison of two conditioning regimens in treatment of leukemia by allogeneic hematopoietic stem cell transplantation].

BACKGROUND & OBJECTIVE: The conditioning regimens are the critical factors in the allogeneic hematopoietic stem cell transplantation. This study was conducted to compare the effectiveness and side-effects of two conditioning regimens in allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: Twenty-one cases received busulfan(BU) 16 mg/kg plus cyclophosphamide(CY) 120 mg/kg,the other 23 cases received total body irradiation(TBI) 7.5-8.5 Gy plus CY 120 mg/kg regimen. RESULTS: The 3-year disease-free survivals (DFS) were 61.5% in BU/CY group and 64.7% in TBI/CY group, respectively (P >0.05). The relapse rates were 23.8% and 26%, respectively, without significant difference (P >0.05). The incidence of liver damage in the BU/CY group was higher (80.9%) than that in the TBI/CY group (54.3%) (P< 0.05), while no case developed hepatic veno-occlusive disease. Stomatitis and gastrointestinal toxicity were significantly lower in the BU/CY group (33.3% and 42.9%) compared with TBI/CY group (78.2% and 78.2%), respectively (P< 0.05). Bladder toxicity (23.8% and 26%) and pulmonary toxicity(14.3% and 13%) were similar in the two groups(P >0.05), while one patient in TBI/CY group developed grade IV pulmonary toxicity, which is lethal. No case was found to have cardiac, renal, or central nervous system grade I toxicity. CONCLUSION: The two groups have equal effectiveness, BU/CY regimen is relatively easy to administer and well tolerated with low extramedullary toxicity.