Prednisone plus IVIg compared with prednisone or IVIg for immune thrombocytopenia in pregnancy: a national retrospective cohort study.

Background: The responses of intravenous immunoglobulin (IVIg) or corticosteroids as the initial treatment on pregnancy with ITP were unsatisfactory. This study aimed to assess the safety and effectiveness of prednisone plus IVIg versus prednisone or IVIg in pregnant patients with immune thrombocytopenia (ITP). Methods: Between 1 January 2010 and 31 December 2020, 970 pregnancies diagnosed with ITP at 19 collaborative centers in China were reviewed in this observational study. A total of 513 pregnancies (52.89%) received no intervention. Concerning the remaining pregnancies, 151 (33.04%) pregnancies received an initial treatment of prednisone plus IVIg, 105 (22.98%) pregnancies received IVIg alone, and 172 (37.64%) pregnancies only received prednisone. Results: Regarding the maternal response to the initial treatment, no differences were found among the three treatment groups (41.1% for prednisone plus IVIg, 33.1% for prednisone, and 38.1% for IVIg). However, a significant difference was observed in the time to response between the prednisone plus IVIg group (4.39 ± 2.54 days) and prednisone group (7.29 ± 5.01 days; p < 0.001), and between the IVIg group (6.71 ± 4.85 days) and prednisone group (p < 0.001). The median prednisone duration in the monotherapy group was 27 days (range, 8-195 days), whereas that in the combination group was 14 days (range, 6-85 days). No significant differences were found among these three treatment groups in neonatal outcomes, particularly concerning the neonatal platelet counts. The time to response in the combination treatment group was shorter than prednisone monotherapy. The duration of prednisone application in combination group was shorter than prednisone monotherapy. The combined therapy showed a lower predelivery platelet transfusion rate than IVIg alone. Conclusion: These findings suggest that prednisone plus IVIg may represent a potential combination therapy for pregnant patients with ITP.

Prediction of postpartum hemorrhage in pregnant women with immune thrombocytopenia: Development and validation of the MONITOR model in a nationwide multicenter study.

Globally, postpartum hemorrhage (PPH) is the leading cause of maternal death. Women with immune thrombocytopenia (ITP) are at increased risk of developing PPH. Early identification of PPH helps to prevent adverse outcomes, but is underused because clinicians do not have a tool to predict PPH for women with ITP. We therefore conducted a nationwide multicenter retrospective study to develop and validate a prediction model of PPH in patients with ITP. We included 432 pregnant women (677 pregnancies) with primary ITP from 18 academic tertiary centers in China from January 2008 to August 2018. A total of 157 (23.2%) pregnancies experienced PPH. The derivation cohort included 450 pregnancies. For the validation cohort, we included 117 pregnancies in the temporal validation cohort and 110 pregnancies in the geographical validation cohort. We assessed 25 clinical parameters as candidate predictors and used multivariable logistic regression to develop our prediction model. The final model included seven variables and was named MONITOR (maternal complication, WHO bleeding score, antepartum platelet transfusion, placental abnormalities, platelet count, previous uterine surgery, and primiparity). We established an easy-to-use risk heatmap and risk score of PPH based on the seven risk factors. We externally validated this model using both a temporal validation cohort and a geographical validation cohort. The MONITOR model had an AUC of 0.868 (95% CI 0.828-0.909) in internal validation, 0.869 (95% CI 0.802-0.937) in the temporal validation, and 0.811 (95% CI 0.713-0.908) in the geographical validation. Calibration plots demonstrated good agreement between MONITOR-predicted probability and actual observation in both internal validation and external validation. Therefore, we developed and validated a very accurate prediction model for PPH. We hope that the model will contribute to more precise clinical care, decreased adverse outcomes, and better health care resource allocation.

Chidamide based combination regimen for treatment of monomorphic epitheliotropic intestinal T cell lymphoma following radical operation: Two case reports.

BACKGROUND: Monomorphic epitheliotropic intestinal T cell lymphoma (MEITL) is a rare extra-nodal T-cell lymphoma that has uniformly aggressive features with a poor prognosis. No standardized treatment protocols have been established. Previous experience has demonstrated favorable outcomes with combination chemotherapy followed by autologous hematopoietic stem cell transplant. However, many patients are unable to tolerate the toxicities. Chidamide is a new histone deacetylase inhibitor that has shown preferential efficacy in mature T-cell lymphoma. CASE SUMMARY: We herein present two cases of MEITL who were both intermediate risk according to enteropathy-associated T cell lymphoma prognostic index. Case one was a 61-year-old man. He complained of upper abdominal pain and intermittent black stool for 2 mo. Imaging examination revealed that the intestinal wall was thickened. He received a partial excision of the small intestine. A chidamide-based combination regimen was given postoperatively. Eleven months later, he presented with recurrence in the bilateral lungs. He passed away 15 mo after his diagnosis. Case two was a 35-year-old woman who complained of abdominal distention for 1 mo. Positron emission tomography/computed tomography demonstrated wall thickening of the small intestine and upper sigmoid colon. Colon perforation and septic shock occurred on the fourth day of her admission. She was treated by sigmoid colostomy. Chidamide-based combination therapy was then provided. She was recurrence-free for 6 mo until lesions were found in the bilateral brain and lived for 17 mo since her diagnosis. Compared to historical data, chidamide seems to improve the prognosis of MEITL slightly. CONCLUSION: MEITL is a type of aggressive lymphoma. Chidamide is a new promising approach for the treatment of MEITL.

[Inhibitory Effect of Curcumin on Proliferation of CD34(+) Acute Myeloid Leukemia Cells and Its Mechanism].

OBJECTIVE: To explore the inhibitory effect of curcumin on proliferation of CD34(+) acute myeloid leukemia cells and its mechamism. METHODS: KG1a and Kasumi-1cell lines were treated with curcumin of different concentrations (0, 40, 60, 80 µmol/L). The effect of curcumin on cell viability and proliferation was detected by trypan blue staining and cell count. The effect of curcumin on distribution of NF-κB P65 subunit was analyzed by immunofluorescence and Western blot. RESULTS: The curcumin inhibited proliferation of KG1a and Kasumi-1 cells in a dose-dependent manner. Western blotting showed that curcumin led to significant down-regulation of NF-κB P65 nuclear protein expression. Immunofluorescence assay showed that treatment with 40 µmol/L of curcumin for 48h suppressed the nuclear translocation of NF-κB p65 in KG1a and Kasumi-1 cells. CONCLUSION: The curcumin suppresses cell growth of KG1a and Kasumi-1 cells, its mechanism may be related to inhibitory effect of curcumin on NF-κB p65 nucleus protein.

ATO/ATRA/anthracycline-chemotherapy sequential consolidation achieves long-term efficacy in primary acute promyelocytic leukemia.

The combination of all-trans retinoic acid (ATRA) and arsenic trioxide (As2O3, ATO) has been effective in obtaining high clinical complete remission (CR) rates in acute promyelocytic leukemia (APL), but the long-term efficacy and safety among newly diagnosed APL patients are unclear. In this retrospective study, total 45 newly diagnosed APL patients received ATRA/chemotherapy combination regimen to induce remission. Among them, 43 patients (95.6%) achieved complete remission (CR) after induction therapy, followed by ATO/ATRA/anthracycline-based chemotherapy sequential consolidation treatment with a median follow-up of 55 months. In these patients, the estimated overall survival (OS) and the relapse-free survival (RFS) were 94.4% ± 3.9% and 94.6 ± 3.7%, respectively. The toxicity profile was mild and reversible. No secondary carcinoma was observed. These results demonstrated the high efficacy and minimal toxicity of ATO/ATRA/anthracycline-based chemotherapy sequential consolidation treatment for newly diagnosed APL in long-term follow-up, suggesting a potential frontline therapy for APL.

Antibody-directed double suicide gene therapy targeting of MUC1- positive leukemia cells in vitro and in vivo.

Our aim was to specifically transfer the cytosine deaminase (CD) and thymidine kinase (TK) genes into mucin 1 (MUC1)-positive leukemia cells by anti-MUC1 antibody directed infection of replication-defective lentivirus and to evaluate the targeted cytotoxicity of double suicide genes to leukemia. The target gene vector (containing CD and TK) and envelope (containing GFP and anti-MUC1) and packaging plasmids were cotransfected into 293T cells to produce the recombinant lentivirus. Suicide genes in virus-infected leukemia cells (U937, Jurkat, and K562) were detected by western blot. The cytotoxicity and bystander effect in vitro and the therapeutic effect in vivo were detected after treatment with the prodrugs. The results revealed that combined treatment with prodrug 5-fluorocytosine (5-FC) and ganciclovir (GCV) inhibited leukemia cell growth and caused significant bystander effect than treatment with either prodrug alone. TK/GCV treatment alone induced degeneration and cell death while the effect of CD/5-FC alone mainly caused vacuolar degeneration and necrosis. The addictive effects of combinatorial use of GCV and 5-FC mainly induced swelling of the mitochondria followed by necrosis of the leukemia cells. In vivo experiments revealed that both single and combinatorial prodrug treatments could prolong the survival time of leukemic mice. In summary, anti-MUC1 antibody directed lentiviral vector successfully transduced dual suicide genes and exerted targeted cytotoxicity against MUC1 positive leukemia cells. This targeted lentiviral dual suicide gene delivering system provides a promising approach for clinical treatment of leukemia in future.

Inhibition of lymphoma cell proliferation by peroxisomal proliferator-activated receptor-γ ligands via Wnt signaling pathway.

Peroxisome proliferator-activated receptor gamma (PPARγ) plays an important role in regulating energy balance, glucose and lipid metabolisms and inflammation. PPARγ also exerts multiple anti-cancer effects including tumor growth and angiogenesis inhibition, induction of cell differentiation, and apoptosis. Perturbed Wnt/ß-catenin signaling likely plays a key role in tumorigenesis and the interaction between PPARγ and the transcriptional regulator ß-catenin maybe important in this process. Phosphorylation of ß-catenin by GSK-3ß inactivates it and suppresses tumor cell proliferation and self-renewal of tumor stem cells. In combination with Frizzled, Wnt suppresses GSK-3ß and causes degradation of ß-catenin and activation of many tumor proliferation factors. In the present study, we investigated the effects of PPARγ agonist rosiglitazone (RGZ) and PPARγ antagonist GW9662 on the growth, mitotic cycle, and apoptosis of human lymphoma cell line, Raji cells. We also studied the influence of PPARγ ligands on the expression of ß-catenin and GSK-3ß in Raji cells to reveal whether Wnt/GSK-3ß/ß-catenin signaling pathways are involved in PPARγ ligands triggered Raji cell apoptosis. Results showed that both RGZ and GW9662 can inhibit the growth of Raji cells by inducing apoptosis and arresting cell cycle; however, there was no correlation between these effects and expression of PPARγ. Both the PPARγ ligands, RGZ and GW9662, appear to reciprocally regulate the mRNA and protein expressions of GSK-3ß, which promotes apoptosis, and of ß-catenin, which blocks apoptosis. These results suggest that PPARγ ligands mediate their effects via Wnt/GSK-3ß/ß-catenin signaling on Raji cell proliferation and survival.

Curcumin reduces expression of Bcl-2, leading to apoptosis in daunorubicin-insensitive CD34+ acute myeloid leukemia cell lines and primary sorted CD34+ acute myeloid leukemia cells.

BACKGROUND: Acute myeloid leukemia (AML) is an immunophenotypically heterogeneous malignant disease, in which CD34 positivity is associated with poor prognosis. CD34+ AML cells are 10-15-fold more resistant to daunorubicin (DNR) than CD34- AML cells. Curcumin is a major component of turmeric that has shown cytotoxic activity in multiple cancers; however, its anti-cancer activity has not been well studied in DNR-insensitive CD34+ AML cells. The aim of this study was to therefore to explore curcumin-induced cytotoxicity in DNR-insensitive CD34+ AML cell lines (KG1a, Kasumi-1), DNR-sensitive U937 AML cells, and primary CD34+ AML bone-marrow-derived cells. METHODS: Primary human CD34+ cells were isolated from peripheral blood mononuclear cells or bone marrow mononuclear cells using a CD34 MicroBead kit. The growth inhibitory effects of curcumin were evaluated by MTT and colony-formation assays. Cell cycle distribution was examined by propidium iodide (PI) assay. Apoptosis was analyzed by Wright-Giemsa, Hoechst 33342 and Annexin-V/PI staining assays. The change in mitochondrial membrane potential (MMP) was examined by JC-1 staining and flow cytometry. Expression of apoptosis-related proteins was determined by reverse transcription-polymerase chain reaction and Western blotting. Short interfering RNA (siRNA) against Bcl-2 was used in CD34+ KG1a and Kasumi-1 cells incubated with/without DNR. RESULTS: Curcumin inhibited proliferation and induced apoptosis and G1/S arrest in both DNR-insensitive KG1a, Kasumi-1 and DNR-sensitive U937 cells. Curcumin-induced apoptosis was associated with reduced expression of both Bcl-2 mRNA and protein, subsequent loss of MMP, and activation of caspase-3 followed by PARP degradation. Curcumin synergistically enhanced the cytotoxic effect of DNR in DNR-insensitive KG1a and Kasumi-1 cells, consistent with decreased Bcl-2 expression. Accordingly, siRNA against Bcl-2 increased the susceptibility of KG1a and Kasumi-1 cells to DNR-induced apoptosis. More importantly, curcumin suppressed Bcl-2 expression, selectively inhibited proliferation and synergistically enhanced the cytotoxicity of DNR in primary CD34+ AML cells, while showing limited lethality in normal CD34+ hematopoietic progenitors. CONCLUSION: Curcumin down-regulates Bcl-2 and induces apoptosis in DNR-insensitive CD34+ AML cell lines and primary CD34+ AML cells.

PPARγ agonist suppresses TLR4 expression and TNF-α production in LPS stimulated monocyte leukemia cells.

It has been well established that inflammation plays a critical role in cancer. Chronic inflammation promotes tumorgenesis and metastasis, which suggests that anti-inflammation drugs could act as a tumor suppressor. It is known that the peroxisome proliferator-activated receptor γ (PPARγ) has been implicated in anti-inflammatory responses; however, the anti-tumor effects of PPARγ have not been intensively investigated. In this study, we examined the effects of PPARγ in cancer. We show that the activation of PPARγ by its agonist rosiglitazone (RGZ) reduces cell proliferation rate in inflammatory and tumor-derived U937 cells. Treatment of RGZ suppresses the expression Toll-like receptor 4 (TLR4) and decreases the production of TNF-α in LPS treated U937 cells. This suggests that NF-κB signaling may be involved in anti-tumor effect of RGZ. Our results demonstrate a role of PPARγ in regulation of NF-κB signaling by modulating TLR4 expression and TNF-α production.

[Pro-apoptotic effect of ciglitazone in leukemic HL-60 cells via PPARγ and P38 MAPK signaling pathway].

OBJECTIVE: To investigate the apoptosis-inducing effect of peroxisome proliferator-activated receptor γ (PPARγ) agonist ciglitazone (CGZ) on leukemic HL-60 cells and its mechanisms of action. METHODS: HL-60 cells in vitro culture medium were subject to different concentrations of CGZ (10-50 µmol/L) for 24, 48 and 72 h. MTT assay was used to detect the cell inhibitory rate and agarose gel electrophoresis to observe DNA fragmentation. Flow cytometry (FCM) and Annexin V/PI staining were used to detect CGZ and/or GW9662 (PPARγ antagonist)-induced cell apoptosis. The expression of PPARγ was examined by RT-PCR and Western blotting. The caspase-3 and protein levels in mitogen-activated protein kinase signaling pathways (MAPKs, p-P38, p-ERK and p-JNK) were also detected. RESULTS: CGZ (over 30 µmol/L) could inhibit the growth of HL-60 cells in both time- and dose-dependent manner. After treatment for 72 h, the cell growth inhibitory rate in 50 µmol/L CGZ (84% ± 11%) treated cells was found more higher than that in both 40 µmol/L and 30 µmol/L CGZ treated cells (72% ± 13%, 59% ± 13%, P < 0.01) and a typical DNA ladder was also observed by agarose gel electrophoresis. The expression of PPARγ was gradually up-regulated by CGZ treatment and could be down-regulated partially by PPARγ antagonist GW9662. The results also revealed that CGZ-induced cell apoptosis (49.7%, 72 h) could not be inhibited thoroughly by GW9662 (36.2%, control:3.2%). It indicated that the CGZ-induced cell apoptosis was partially PPARγ-independent. Western blotting showed a cleavage of caspase-3 zymogen protein and up-regulation of p-P38 protein. Thus it indicated that the activations of caspase-3 and P38 MAPK were involved in CGZ-induced cell apoptosis. CONCLUSION: CGZ inhibits cell growth by induction of cell apoptosis in HL-60 cells via PPARγ dependent and independent signaling pathways. The activations of caspase-3 and P38 MAPK may be one of the important mechanisms in CGZ in treated HL-60 cells.

Down-regulation of telomerase activity and activation of caspase-3 are responsible for Tanshinone I-induced apoptosis in monocyte leukemia cells in vitro.

Tanshinone I (Tan-I) is a diterpene quinone extracted from the traditional herbal medicine Salvia miltiorrhiza Bunge. Recently, Tan-I has been reported to have anti-tumor effects. In this study, we investigated the growth inhibition and apoptosis inducing effects of Tan-I on three kinds of monocytic leukemia cells (U937, THP-1 and SHI 1). Cell viability was measured by MTT assay. Cell apoptosis was assessed by flow cytometry (FCM) and AnnexinV/PI staining. Reverse transcriptase polymerase chain reaction (RT-PCR) and PCR-enzyme-linked immunosorbent assay (ELISA) were used to detect human telomerase reverse transcriptase (hTERT) expression and telomerase activity before and after apoptosis. The activity of caspase-3 was determined by Caspase colorimetric assay kit and Western blot analysis. Expression of the anti-apoptotic gene Survivin was assayed by Western blot and Real-time RT-PCR using the ABI PRISM 7500 Sequence Detection System. The results revealed that Tan-I could inhibit the growth of these three kinds of leukemia cells and cause apoptosis in a time- and dose-dependent manner. After treatment by Tan-I for 48 h, Western blotting showed cleavage of the caspase-3 zymogen protein with the appearance of its 17-kD subunit, and a 89-kD cleavage product of poly (ADP-ribose) polymerase (PARP), a known substrate of caspase-3, was also found clearly. The expression of hTERT mRNA as well as activity of telomerase were decreased concurrently in a dose-dependent manner. Moreover, Real-time RT-PCR and Western blot revealed a significant down-regulation of Survivin. We therefore conclude that the induction of apoptosis by Tan-I in monocytic leukemia U937 THP-1 and SHI 1 cells is highly correlated with activation of caspase-3 and decreasing of hTERT mRNA expression and telomerase activity as well as down-regulation of Survivin expression. To our knowledge, this is the first report about the effects of Tan-I on monocytic leukemia cells.

Inactivation of PI3k/Akt signaling pathway and activation of caspase-3 are involved in tanshinone I-induced apoptosis in myeloid leukemia cells in vitro.

Tanshinone I (Tan I), a diterpene quinone extracted from herbal medicine Salvia miltiorrhiza Bunge, has recently been reported to have antitumor effects. As the mechanism of its proapoptotic effects on human myeloid leukemia cells has not been extensively studied, we performed an in-depth evaluation of the effects of Tan I on apoptosis in human K562 and HL-60 cells. The results revealed that Tan I could inhibit the growth of leukemia cells and cause apoptosis in a time- and dose-dependent manner. Apoptosis was observed clearly by flow cytometry and Hoechst 33258 staining, as well as DNA fragmentation analysis. After treatment by Tan I for 48 h, the percentage of disruption of mitochondrial membrane potential (Δψm) was increased in a dose-dependent manner. Western blotting analysis demonstrated the cleavage of caspase-3 zymogen protein and a dose-dependent cleavage of poly-(ADP-ribose) polymerase. Tan I-induced apoptosis was accompanied by a significant decrease in survivin and an increase in Bax. Moreover, Tan I treatment remarkably downregulated the phosphorylation of both P85/PI3K and Akt in a time-dependent manner, and the PI3K/AKT-specific inhibitor (LY294002) mimicked the apoptosis-inducing effects of Tan I. We therefore conclude that the induction of apoptosis by Tan I in these leukemia cells is mainly related to the disruption of Δψm, the upregulation of Bax expression, and the activation of caspase-3. This process is highly correlated with the inactivation of PI3K/Akt/survivin signaling pathways. The results indicate that Tan I may serve as an effective adjunctive reagent in the treatment of leukemia.

[Correlation of donor and recipient serum interleukin 2 and tumor necrosis factor alpha levels to acute graft-versus-host disease in hematopoietic stem cell transplantation].

OBJECTIVE: To study the relationship between the donor and recipient serum interleukin 2 (IL-2) and tumor necrosis factor alpha (TNF-alpha) levels and the occurrence of acute graft-versus-host disease (aGVHD) following hematopoietic stem cell transplantation. METHODS: Twenty-two leukemic patients undergoing allo-hematopoietic stem cells transplantation and their donors were examined for serum levels of IL-2 and TNF-alpha using ELISA during conditioning and after the transplantation. IL-2 and TNF-alpha levels were also detected in the donors during mobilization to analyze the relationship between the cytokines and aGVHD. RESULTS: Five recipients showed no aGVHD, 10 developed grade I aGVHD, and 7 developed grade II-IV aGVHD. The serum levels of IL-2 and TNF-alpha after conditioning and post-transplantation were significantly higher in the recipients with grade II-IV aGVHD than in those with grade 0-I aGVHD, but no difference was found before the pre-conditioning. The serum IL-2 levels in the mobilized donors for the recipients with grade II-IV aGVHD were significantly higher than that in donors for recipients with grade 0-I aGVHD, whereas the levels of TNF-alpha showed no such a difference. CONCLUSION: Serum IL-2 and TNF-alpha levels in the leukemic patients after conditioning and post-transplantation, and the donor serum IL-2 level after mobilization may be correlative to the severity of aGVHD and can be used as indicators for predicting the severity of aGVHD after the transplantation.

Activation of peroxisome proliferator-activated receptor-gamma induces apoptosis on acute promyelocytic leukemia cells via downregulation of XIAP.

In the present study we investigated the in vitro apoptosis inducing effects of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) ligand ciglitazone (CGZ) on acute promyelocytic leukemia (APL) NB4 cells and its mechanisms of action. The results revealed that CGZ (10-50 micromol/l) inhibited the growth of leukemia NB4 cells and caused apoptosis in a time- and dose-dependent manner. Apoptosis was observed clearly by flow cytometry (FCM) and DNA fragmentation analysis. After treatment by CGZ for 48 h, the percentage of disruption of mitochondrial membrane potential (Deltapsim) was increased in a dose-dependent manner. Western blotting demonstrated the cleavage of caspase-3 zymogen protein and a time-dependent cleavage of poly (ADP-ribose) polymerase (PARP). The results also demonstrated that PPAR-gamma expression was increased concomitantly when apoptosis occurred, and that CGZ-induced apoptosis was inhibited by the PPAR-gamma antagonist GW9662, suggesting a PPAR-gamma dependent signaling pathway in CZG-induced cell death. Moreover, CGZ treatment remarkably downregulated the expression of the X-linked inhibitor of apoptosis protein (XIAP), which was inhibited by GW9662. Of note, a small-molecule XIAP antagonist (1396-12) mimicked the effect of CGZ-induced apoptosis via activation of caspase-3, 7 and 9. The apoptosis-inducing effects by CGZ on fresh APL cells were also found to be remarkable by using FCM and Wright's staining observation. Taken together, our results suggest that downregulation of XIAP and activation of capase-3 play an important role in mediating the PPAR-gamma-dependent cell death induced by CGZ in APL cells. These data provide a novel insight into potential therapeutic strategies for treatment of leukemia.

[Construction of genetically modified dendritic cell vaccine expressing bcr/abl fusion gene and inducing specific cytotoxic T lymphocytes to kill K562 cells in vitro].

BACKGROUND AND OBJECTIVE: Specific immunological effect mediated by T lymphocytes plays an important role in treating chronic myelocytic leukemia (CML). Dendritic cells (DCs)-based immunotherapy has become popular in treating tumors. This study was to construct DC vaccines by transducing with replication-defective recombinant adenoviruses expressing bcr/abl fusion gene of CML, observe the lethal effects of specific cytotoxic T lymphocytes (CTLs) triggered by genetically modified DC vaccines expressing bcr/abl fusion gene against K562 cells in vitro. METHODS: DNA fragment of bcr/abl fusion gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR) to construct a recombinant adenovirus vector and produce recombinant adenoviruses. DCs were induced from peripheral blood monocytes in vitro, and transfected with recombinant adenoviruses or pulsed with peptide to induce specific CTLs. The lethal effect of CTLs against leukemic K562 cells in vitro was observed. RESULTS: We successfully constructed the replication-defective recombinant adenoviral vector expressing bcr/abl fusion gene. The recombinant adenoviruses we produced had a high virus titer of 2.0 x 10(10) pfu/mL. Transfection efficiency of DCs in vitro was 50%-60%. DC vaccines expressing bcr/abl fusion gene were successfully prepared and used to induce specific CTLs. With effector:target cell ratios of 40:1 and 20:1, the killing rates of K562 cells by CTLs were (47.6+/-4.7)% and (47.5+/-1.6)% in genetically modified DCs group, (25.8+/-4.4)% and (24.6+/-6.3)% in peptide-pulsed DCs group, and were (5.7+/-1.3)% and (4.5+/-1.6)% in control DCs group. The differences between every two groups were significant (all P<0.05). CONCLUSION: Genetically modified DC vaccine expressing bcr/abl fusion gene has a stronger contribution than peptide-pulsed DCs in triggering specific CTLs against K562 cells.

Peroxisome proliferator-activated receptor-gamma agonist rosiglitazone--induced apoptosis in leukemia k562 cells and its mechanisms of action.

This study investigates the ability of a synthetic PPAR-gamma agonist, rosiglitazone (RGZ), to induce apoptosis in leukemia K562 cells. The results revealed that RGZ (>40 mmol/L) inhibits the growth of K562 cells and causes apoptosis in a time and dose-dependent manner. Apoptosis is observed clearly by Hoechst 33258 staining. Western blotting analysis demonstrates the cleavage of caspase-3 zymogen protein with the appearance of its 17-kD subunit and a dose-dependent cleavage of poly (ADP-ribose) polymerase. Furthermore, RGZ treatment down-regulates anti-apoptotic protein Bcl-2 and up-regulates pro-apoptotic protein Bax in a dosedependent manner after the cells are treated for 48 hours. Telomerase activity is decreased concurrently in a dosedependent manner. We therefore conclude that RGZ induces apoptosis in K562 cells in vitro, and that RGZ-induced apoptosis in K562 cells is highly correlated with activation of caspase-3, decreasing telomerase activity, down-regulation of the anti-apoptotic protein Bcl-2, and up-regulation of the pro-apoptotic protein Bax.

Downregulation of cyclooxygenase-2 expression and activation of caspase-3 are involved in peroxisome proliferator-activated receptor-gamma agonists induced apoptosis in human monocyte leukemia cells in vitro.

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is a transcription factor important in fat metabolism and PPAR-gamma agonists were recently demonstrated to affect proliferation, differentiation, and apoptosis of different cell types. In the present study, two PPAR-gamma agonists, 15-deoxy-delta (12,14)-prostaglandin J2 (15d-PGJ2) and a synthetic PPAR-gamma agonist troglitazone (TGZ), were used to investigate activated PPAR-gamma-induced apoptosis on human monocyte leukemia U937 and Mono Mac 6 cells in vitro. The results showed that both U937 and Mono Mac 6 cells demonstrated constitutive activation of COX-2 expression; treatment by 15d-PGJ2 and TGZ could induce apoptosis remarkably in human monocyte leukemia cells by disruption of mitochondrial membrane potential, activation of caspase-3, and causing cleavage of the caspase substrate poly (ADP-ribose) polymerase (PARP). Further studies revealed that treatment by both 15d-PGJ2 and TGZ remarkably downregulated COX-2 expression in these two kind of monocyte leukemia cells as measured by reverse transcriptase PCR (RT-PCR) and Western blot. Furthermore, the expression of Bcl-2 and Bcl-Xl and Mcl-1 was downregulated while Bax expression was upregulated concurrently after the cells were treated by these two agonists, and no variations were found in other Bcl-2 family members such as Bak, Bid, and Bad. Taken together, our results demonstrate for the first time that downregulation of cyclooxygenase-2 expression, disruption of mitochondrial membrane potential, activation of caspase-3, downregulation of Bcl-2, Bcl-Xl, and Mcl-1, and upregulation of Bax are involved in PPAR-gamma agonists-induced apoptosis in these two human monocyte leukemia cells.

Induction of apoptosis and inhibition of cell adhesive and invasive effects by tanshinone IIA in acute promyelocytic leukemia cells in vitro.

Tanshinone IIA, a diterpene quinone extracted from the traditional herbal medicine, Salvia miltiorrhiza Bunge, is used widely and successfully in clinics in China for treating inflammatory diseases. Recently tanshinone IIA has been reported to have apoptosis inducing effects on a large variety of cancer cells. In this study, the anti-proliferation and apoptosis inducing effects of tanshinone IIA as well as its influence on cell adhesion to and invasion through the extracellular matrix (ECM) on acute promyelocytic leukemia (APL) NB4 cells in vitro were studied. Cell proliferation was assessed by MTT assay, cell apoptosis was observed by Hoechst 33258 staining and flow cytometry (FCM); The variation of caspase-3 and apoptotic related genes were assayed by Western blotting, cell mitochondrial membrane potential as well as cell adhesive and invasive effects were also investigated by using standard methods. The results showed that tanshinone IIA exhibited induction of apoptosis by activation of caspase-3, downregulation of anti-apoptotic protein bcl-2 and bcl-xl and upregulation of pro-apoptotic protein bax, as well as disruption of the mitochondrial membrane potential. Furthermore, treatment by tanshinone IIA could reduce cell adhesion to and invasion through ECM in leukemia NB4 cells. These data provide a potential mechanism for tanshinone IIA-induced apoptosis and cell growth inhibition in leukemia NB4 cells, suggesting that tanshinone IIA may serve as an effective adjunctive reagent for the treatment of APL.

[In vitro study of cytotoxic T lymphocyte activation by antigen-loaded dendritic cells for killing of K562 cells].

OBJECTIVE: To study the effect of dendritic cells (DC) stimulated with K562 cell lysate in inducing specific cytotoxic T lymphocytes (CTL) against K562 cells in vitro. METHODS: The DCs were derived from healthy human peripheral blood monocytes in the presence of granulocyte-macrophage colony-stimulating factor, interleukin (IL)-4 and tumor necrosis factor (TNF) alpha. The T cells were stimulated by DCs loaded with freeze-thawed K562 cells and T-cell cytotoxicities were measured by lactate dehydrogenase (LDH) assay. RESULTS: The DCs could be successfully obtained from peripheral blood monocyte after the culture. Mixed lymphocyte reactions induced by the antigen-loaded DC were much stronger than those induced by human peripheral blood monocytes (P<0.05). At the effector to target ratio of 10:1 and 20:1, cytotoxicities against K562 cells by CTL derived from culture with the antigen-loaded DCs were the strongest (P<0.05). CONCLUSION: CTL derived from DCs pulsed with K562 cell lysate show effective and specific cytotoxicity against K562 cells.