A modified drag coefficient model for calculating the terminal settling velocity and horizontal diffusion distance of irregular plume particles in deep-sea mining.

Deep-sea mining inevitably produces plumes, which will pose a serious threat to the marine environment with the continuous movement and diffusion of plumes along with ocean currents. The terminal settling velocity (wt) of irregular particles is one of the crucial factors for determining the plumes' diffusion range. It is generally calculated by drag coefficient (CD), while most existing CD models only consider single shape characteristic parameter or have a smaller range of Reynolds number (Re). In this study, a new shape factor (γ) of irregular particles is proposed by considering the thickness (one-dimension), the projected area (two-dimension), and the surface area (three-dimension) of irregular particles as well as their coupling effect to establish a modified CD model for calculating the wt. A modified Gaussian plume model is proposed to predict the horizontal diffusion distance of the plume particles by considering the settling velocity and diffusion effect of irregular particles. Research results show that the wt increases nearly linearly, with a gradually decreased slope and slightly then greatly with the increasing of γ, dp (diameter) and ρp (density), respectively. The modified CD model is verified to be more valid with a wider application range (Re < 3×105) than five existing CD models by the test results. The larger the ρp or dp, the larger the wt and thus the smaller the Sh. This study could provide a theoretical basis for calculating the plume diffusion range to further study the impact of deep-sea mining on the ocean environment.

Accumulation of circulating myeloid-derived suppressor cell subsets: predicting poor clinical efficacy and prognosis through T cell suppression in non-Hodgkin's lymphoma.

Myeloid-derived suppressor cells (MDSCs) are implicated in the regulation of immune responses closely associated with poor clinical outcomes in cancer. However, the MDSC subtypes in non-Hodgkin's lymphoma (NHL) have not been systematically investigated. So, we investigated the percentage of MDSC subsets in 78 newly diagnosed NHL patients by flow cytometry. The results showed that all MDSC subsets increased in NHL patients compared with healthy donors. Notably, MDSCs, monocytic MDSCs, and CD14 + CD66b + MDSCs significantly increased in NHL patients compared with those with lymphadenitis donors. polymorphonuclear MDSCs (PMN-MDSCs), early-stage MDSCs (e-MDSCs), and the International Prognostic Index were independent risk factors for poor clinical efficacy and were involved in constructing the nomogram for predicting clinical efficacy. Progression-free survival (PFS) was significantly shorter in patients with high level of MDSC subsets, and PMN-MDSCs emerged as an independent prognostic factor for PFS. PMN-MDSCs, e-MDSCs, and the International Prognostic Index were involved in constructing the nomogram for predicting PFS. Patients with a higher percentage of MDSCs, PMN-MDSCs, e-MDSCs, and CD14 + CD66b + MDSCs experienced a shorter overall survival compared with those with lower percentages. In addition, research on mechanisms found that T cell function was suppressed and mediated by the expansion of MDSCs via involving arginase-1 and interleukin-10 in vitro and in vivo. In conclusion, our study demonstrates that the increased circulating MDSC subsets predict poor clinical efficacy and prognosis in NHL, potentially involving T cell suppression through MDSC subset expansion. These findings indicate the potential of MDSC subsets as comprehensive diagnostic, prognostic biomarkers, and therapeutic targets for NHL.

A novel CD19/CD22/CD3 trispecific antibody enhances therapeutic efficacy and overcomes immune escape against B-ALL.

The bispecific T-cell engager (BiTE) blinatumomab against CD19 and CD3 has emerged as the most successful bispecific antibody (bsAb) to date; however, a significant proportion of patients do not respond to the treatments or eventually experience relapse after an initial response, and the recurrence rate increases significantly due to escape or downregulation of the CD19 antigen. To enhance antitumor efficacy and overcome potential immune escape, we developed a novel approach to design a CD19/CD22/CD3 trispecific antibody (tsAb) by site-specifically fusing anti-CD19 scFv (FMC63) and anti-CD22 nanobody (Nb25) to the defined sites of the CD3 antigen-binding fragment (Fab, SP34). This strategy allows for the optimal formation of immune synapses mediated by CD19/CD22/CD3 between target cells and T cells. Optimized tsAb can be superior for inducing T-cell-specific cytotoxicity and cytokine production against CD19+ and/or CD22+ tumor cells compared to other tsAb formats, and demonstrated significantly enhanced antitumor efficacy and the ability to overcome immune escape compared with the corresponding bsAbs alone or in combination, as well as with blinatumomab. In addition, tsAb treatment can lead to the long-term elimination of primary B-ALL patient samples in the PDX model and significantly prolong survival. This novel approach provides unique insight into the structural optimization of T-cell-redirected multispecific antibodies using site-specific recombination, and may be broadly applicable to heterogeneous and resistant tumor populations as well as solid tumors.

Levitt's CO breath test in the differential diagnosis of chronic isolated hyperbilirubinemia.

A key component of the differential diagnosis of isolated hyperbilirubinemia (HB) is distinguishing between hemolytic and non-hemolytic types. Routine hemolysis screening markers have unsatisfactory sensitivity and specificity. Erythrocyte (RBC) lifespan shortening, the gold standard marker of hemolysis, is seldomly measured due to the cumbersome and protracted nature of standard methods. A new Levitt's CO breath test method may enable simple, rapid RBC lifespan measurement. In this pilot prospective diagnostic study, Levitt's CO breath test was evaluated to discriminate hemolytic from non-hemolytic HB in adults. One hundred and thirty eligible non-smoking adult patients who were aged 18 or older, referred for chronic (>6 months) isolated HB or had a known diagnosis of isolated HB of a rare cause, were recruited, including 77 with non-hemolytic HB and 53 with hemolytic HB. ROC curve analysis was applied to determine the optimal cutoff for discriminating between hemolytic and non-hemolytic HB, and the performance was calculated. Results showed that the mean RBC lifespan in non-hemolytic HB (93 ± 26 d) was reduced (p= 0.001 vs. normal reference value of 126 d), but longer than that in hemolytic HB (36 ± 17 d;p= 0.001). RBC lifespans did not differ significantly between 26 patients with simple hemolytic HB (32 ± 14 d) and 27 patients with a Gilbert syndrome comorbidity (40 ± 18 d). ROC curve analysis revealed an optimal lifespan cutoff for discriminating between hemolytic and non-hemolytic HB of 60 d (AUC = 0.982), with a diagnostic accuracy of 95.4%, 94.3% sensitivity and 96.1% specificity respectively. These results indicate that Levitt's CO breath test seems to be very sensitive and specific for detecting hemolysis in adult patients with chronic isolated HB, and could enable simple, rapid, and reliable differential diagnosis of isolated HB. A large-scale validation study of the method is warranted.

Abnormally Short Erythrocyte LifeSpan in Three Patients with Primary Myelofibrosis Despite Successful Control of Splenomegaly.

Splenectomy is an elective operation for refractory anemia in patients with primary myelofibrosis (PMF). We found that 3/3 patients with PMF in our department continued to have very shortened erythrocyte (RBC) lifespans (35 days, 66 days, and 37 days, respectively) after treatment-alleviated splenomegaly. These outcomes suggest that intravascular hemolysis predominantly independent of hypersplenism may underlie, at least to some extent, peripheral hemolysis in patients with PMF. More cases studies are needed to elucidate the role of splenomegaly in PMF-associated anemia.

An Immune Risk Score Predicts Survival of Patients with Acute Myeloid Leukemia Receiving Chemotherapy.

PURPOSE: Prediction models for acute myeloid leukemia (AML) are useful, but have considerable inaccuracy and imprecision. No current model includes covariates related to immune cells in the AML microenvironment. Here, an immune risk score was explored to predict the survival of patients with AML. EXPERIMENTAL DESIGN: We evaluated the predictive accuracy of several in silico algorithms for immune composition in AML based on a reference of multi-parameter flow cytometry. CIBERSORTx was chosen to enumerate immune cells from public datasets and develop an immune risk score for survival in a training cohort using least absolute shrinkage and selection operator Cox regression model. RESULTS: Six flow cytometry-validated immune cell features were informative. The model had high predictive accuracy in the training and four external validation cohorts. Subjects in the training cohort with low scores had prolonged survival compared with subjects with high scores, with 5-year survival rates of 46% versus 19% (P < 0.001). Parallel survival rates in validation cohorts-1, -2, -3, and -4 were 46% versus 6% (P < 0.001), 44% versus 18% (P = 0.041), 44% versus 24% (P = 0.004), and 62% versus 32% (P < 0.001). Gene set enrichment analysis indicated significant enrichment of immune relation pathways in the low-score cohort. In multivariable analyses, high-risk score independently predicted shorter survival with HRs of 1.45 (P = 0.005), 2.12 (P = 0.004), 2.02 (P = 0.034), 1.66 (P = 0.019), and 1.59 (P = 0.001) in the training and validation cohorts, respectively. CONCLUSIONS: Our immune risk score complements current AML prediction models.

Gilbert's syndrome coexisting with hereditary spherocytosis might not be rare: Six case reports.

BACKGROUND: Both Gilbert's syndrome (GS) and hereditary spherocytosis (HS) are common genetic disorders. However, comorbidity of GS with HS has always been considered a rare phenomenon, and it can impede accurate diagnoses in the presence of isolated unconjugated hyperbilirubinemia. CASE SUMMARY: In a study on Levitt's carbon monoxide (CO) breath test for the differential diagnosis of isolated hyperbilirubinemia, we found six GS patients with HS in 6 mo. The patients, including five males and one female, aged 25-58 years, were from four families and generally in good health. Their chronic fluctuating jaundice and/or hyperbilirubinemia had been diagnosed as simple constitutional jaundice for 6-30 years. Liver function tests showed isolated unconjugated hyperbilirubinemia with serum total bilirubin ranging from 20.7-75.4 µmol/L. Blood hemoglobin was normal in five cases, and slightly decreased in one (11.5 g/dL). Overt hemolytic signs were absent, while erythrocyte lifespan determined by the newly developed Levitt's CO breath test was significantly short (15-50 d), definitely demonstrating the presence of hemolysis. Given that their unconjugated hyperbilirubinemia compared inappropriately with hemolytic severity, as indicated by the hemoglobin level, further combined genetic tests for both UGT1A1 and hereditary erythrocyte deficiencies were conducted. These tests confirmed, at last, the coexistence of GS with HS. CONCLUSION: Comorbidity of GS and HS might not be uncommon in isolated unconjugated hyperbilirubinemia. While CO breath test would sensitively detect the hemolysis, the discordance between the hyperbilirubinemia and hemoglobin level could strongly indicate the coexistence of GS and HS.

[Effect of Metformin on Proliferation of Multiple Myeloma Cells].

OBJECTIVE: To investigate the effects of metformin on proliferation and apoptosis in multiple myeloma cell line RPMI8226 and U266, and to clarify the molecular mechanism of proliferation inhibition and apoptosis induced by metformin. METHODS: RPMI8226, U266 cells were treated with 0, 5, 10, 20, 40, 80 mmol/L of metformin for 24, 48 and 72 hours, then the inhibition rate was detected by CCK-8; RPMI8226 cells were treated with 0, 10, 20, 40 mmol/L of metformin for 48 hours, the apoptosis rates were detected by flow cytometry with Annexin-V-FITC/PI double staining; RPMI8226 cells were treated with 0, 5, 10, 20 mmol/L of metformin for 48 hours, the expressions of Caspase-3, PARP, STAT3, p-STAT3, BCL-2, Cyclin D1 and P21 were detected by Western blot. RESULTS: The inhibition rate increased in RPMI8226 and U266 cells treated with metformin in the dose- (r=0.982, r=0.967, P<0.05) and time-dependent (r=0.956, r=0.962, P<0.05) manner; the apoptosis rate increased(r=0.976, P<0.05) in RPMI8226 cells treated with metformin; it also was found that procaspase-3 was degraded and PARP was cleaved when treated with metformin. Proliferation inhibition and apoptosis of RPMI8226 cells were related with inhibition of STAT3 phosphorylation, down-regulation of BCL-2 and Cyclin D1, and up-regulation of P21. CONCLUSION: Metformin can inhibit the proliferation and induce apoptosis of RPMI8226 and U266 cell lines, which may be related to down-regulation of STAT3 signal transduction pathway.

Uric Acid Induces Endothelial Dysfunction by Activating the HMGB1/RAGE Signaling Pathway.

Uric acid (UA) is a risk factor for endothelial dysfunction, a process in which inflammation may play an important role. UA increases high mobility group box chromosomal protein 1 (HMGB1) expression and extracellular release in endothelial cells. HMGB1 is an inflammatory cytokine that interacts with the receptor for advanced glycation end products (RAGE), inducing an oxidative stress and inflammatory response, which leads to endothelial dysfunction. In this study, human umbilical vein endothelial cells (HUVECs) were incubated with a high concentration of UA (20 mg/dL) after which endothelial function and the expression of HMGB1, RAGE, nuclear factor kappa B (NF-κB), inflammatory cytokines, and adhesion molecules were evaluated. UA inhibited endothelial nitric oxide synthase (eNOS) expression and nitric oxide (NO) production in HUVECs, increased intracellular HMGB1 expression and extracellular HMGB1 secretion, and upregulated RAGE expression. UA also activated NF-κB and increased the level of inflammatory cytokines. Blocking RAGE significantly suppressed the upregulation of RAGE and HMGB1 and prevented the increase in DNA binding activity of NF-κB and the levels of inflammatory cytokines. It also blocked the decrease in eNOS expression and NO production induced by UA. Our results suggest that high concentrations of UA cause endothelial dysfunction via the HMGB1/RAGE signaling pathway.

Cutaneous clear cell/signet-ring cell squamous cell carcinoma arising in the right thigh of a patient with type 2 diabetes: combined morphologic, immunohistochemical, and etiologic analysis.

BACKGROUND: The clear cell/signet-ring cell variant of cutaneous squamous cell carcinoma (cSCC) is extremely rare. Its carcinogenesis has consistently been linked to ultraviolet radiation and HPV in the literature. However, there is little definite information about the contribution of diabetes mellitus (DM) to cSCC. CASE PRESENTATION: A 78-year-old Chinese woman with type 2 DM presented with a mushroom-like lump in her right thigh. Histological findings revealed that the lesion was mainly composed of clear cells and signet-ring cells. The septa of vacuoles in cytoplasm displayed positivity for periodic acid schiff (PAS) and cytokeratins such as AE1/AE3, CK5/6, CK14, and CK19. Malignant cells did not express CK7, CK8, CK18, CK20, p16, p53, or c-erbB-2, and the Ki-67 index was less than 5 %. We further explored the etiology of clear cell/signet-ring cell cSCC using human papillomavirus (HPV) type-specific PCR and genotyping and confirmed that the patient was not infected with HPV. Nucleus positivity for p63 indicated the involvement of the p53 family in the lesion. Meanwhile, the expression of fibroblast growth factor receptor-2 (FGFR2), a downstream effector of p63, was upregulated in tumor cells. CONCLUSIONS: This study provides the first report on the clear cell/signet-ring cell variant of cSCC found in the right thigh of a patient with type 2 DM. Metabolic imbalance in addition to conventional pathogens such as UV and HPV may contribute to the development of the lesion via p63/FGFR2 axis.

[Effect of PKF118-310 on Cell Cycle and Proliferation of K562 Cells and Its Mechanism].

UNLABELLED: Objetive: To investigate the effects of PKF118-310 on cell cycle and proliferation of K562 cell lines and its mechanism. METHODS: After treatment of PKF118-310 with different concentration, the proliferation inhibition on K562 cell lines was detected by MTT, the existance of ß-catenin and TCF-4 in the cells was observed by immunohistochemistry. The change of the cell cycle was detected by flow cytometry. The expressions of caspase-3, ß-catenin, TCF and BCL-9 were detected by Western blot. RESULTS: PKF118-310 can inhibit the proliferation of K562 cell line by S phase blocking. The ß-catenin and TCF in the cells were observed by immunohistochemistry. After treating this cell line with PKF118-310 of different concentrations for 72 h, the expression level of caspase-3 increased, the expression levels of ß-catenin, TCF and BCL-9 significantly decreased. CONCLUSION: PKF118-310 induces cycle arest of K562 cells at the S phase and inhibits the proliferation of these cells through decreasing ß-catenin/TCF/BCL-9 thrascriptional activity.

[Mechanism of cinnamic aldehyde-inducing apoptosis of chronic myeloid leukemic cells in vitro].

The aim of this study was to investigate the apoptosis-inducing effect of cinnamic aldehyde (CA) on chronic myeloid leukemic (CML) cells and its mechanism. K562 cells and primary bone marrow mononuclear cells (MNC) from patients with CML were treated by various concentrations of CA. Flow cytometry was employed to measure the apoptosis of K562 cells and primary CML bone marrow MNC. Western blot was used to determine the expression of C-MYC and the phosphorylation of CrkL in K562 cells, and real-time polymerase chain reaction (real-time PCR) was used to quantify the expression of BCR-ABL mRNA in K562 cells. The results indicated that CA induced the apoptosis of K562 cells in a time- and dose-dependent manner. CA induced apoptosis of CML MNC dose-dependently. CA inhibited the expression of BCR-ABL mRNA and C-MYC, reduced CrkL phosphorylation levels in K562 cells. It is concluded that CA induces apoptosis of CML cells in vitro. Down-regulation of the expression and function of BCR-ABL may be one of its most important anti-leukemia mechanisms.

[Effect of rapamycin on proliferation, apoptosis and regulation of chemokine receptor CXCR4 in RPMI8226 cells].

This study was purposed to investigate the effect of rapamycin on proliferation, apoptosis, cell cycle progression and the regulation of chemokine receptor CXCR4 on RPMI8226 cells. Different concentrations of rapamycin were used to treat the multiple myeloma cell line RPMI8226 for different times. The proliferation of the cells was detected by MTT assay; the apoptosis rate and cell cycle were determined by flow cytometry (FCM); apoptosis of cells was observed by inverted microscopy; the cylin D1, CXCR4 and mTOR mRNA expressions were detected by RT-PCR or FQ-PCR after treating RPMI8226 cells with different concentrations of rapamycin. The results indicated that the rapamycin could inhibit the proliferation of RPMI8226 cells and induce their apoptosis. The cell cycle was arrested at the G(0)/G(1) phase. PCR results showed the down-regulation of mTOR, cyclin D1 and mTOR mRNA expressions after treating RPMI8226 cells with different concentrations of rapamycin for 24 hours. It is concluded that the rapamycin significantly inhibits the growth of RPMI8226 cells in a dose-and time-dependent mannes and induce cell apoptosis. Cell cycle arrests at the G(0)/G(1) phase, may be due to the down-regulation of the mTOR and cyclin D1 expressions. In additions, the down-regulation of CXCR4 mRNA expression is correlated with the reduction of adhesion between myeloma cells and stromal cells.

mitochondrial ceramidase overexpression up-regulates Bcl-2 protein level in K562 cells, probably through its metabolite sphingosine-1-phosphate.

Recently, a mitochondrial ceramidase has been identified and cloned, whose mitochondrial localization strongly suggests the existence of an unexpected mitochondrial pathway of ceramide metabolism that may play a key role in mitochondrial functions, especially in the regulation of apoptosis. To explore the biological effect of mitochondrial ceramidase on cells, pcDNA 3.1/His-CDase plasmid, containing mitochondrial ceramidase cDNA sequence, was transducted into K562 cells mediated by liposome, and G418 was used to screen for positive colonies. A stable transfected K562 cell line was established and named as 'K562TC'. The difference between K562 and K562TC cells in chemotheraputic cytotoxicity response and serum-withdrawal resistance and Bcl-2 protein expression were evaluated by MTT assay, annexin V/PI test, flow cytometry or Western blotting, respectively. The results showed that although survival was comparable between K562 and K562TC cells after exposed to adriamycin, etoposide or arsenious acid, K562TC cells with elevated Bcl-2 protein expression level as identified by FCM or Western blotting revealed stronger resistance to apoptosis induced by serum withdrawal than their parental cells. Inhibition of mitochondrial ceramidase expression in K562TC cells by its specific antisense oligodeoxynucleotide was correlated with a decrease in Bcl-2 protein level. N, N-dimethylsphingosine, a sphingosine kinase inhibitor, depleted intracellular sphingosine-1-phosphate production, also abrogated Bcl-2 protein expression in K562TC cells, while Bcl-2 protein level in K562 cells was up-regulated by exogenous sphingosine-1-phosphate. It is concluded that mitochondrial ceramidase overexpression in K562 cells leads to markedly elevated level of Bcl-2 protein and results in more resistance to serum withdrawal. This effect is initiated not by sphingosine, the direct metabolite of mitochondrial ceramidase, but via sphingosine-1-phosphate, its phosphorylated form. This is the first evidence that mitochondrial ceramidase, through its sphingoid metabolite sphingosine-1-phosphate, up-regulates Bcl-2 protein expression in K562 cells.

Mutation analysis of SHIP gene in acute leukemia.

The SH2 domain containing inositol 5'-phosphatase (SHIP) was initially described as a 145 kD protein phosphorylated on tyrosines upon growth factor and cytokine stimulation. SHIP is predominately expressed in hematopoietic cells, and is a crucial negative regulator in the development of hematopoietic cells. To evaluate the role of the SHIP gene in human leukemogenesis, expression and mutation of SHIP gene in bone marrow and/or peripheral blood from 32 patients with acute myeloid leukemia (AML), 9 patients with acute lymphoblastic leukemia (ALL), as well as human hematopoietic cell lines were analyzed by reverse transcription-polymerase chain reaction (RT-PCR), single strand conformational polymorphism (SSCP) and sequencing. The RT-PCR showed that all samples expressed SHIP gene. Mutations of SHIP gene were detected in 7 out of 32 AML patients (22%) and one out of 9 ALL patients (12%). Interestingly, two missense mutations that had been observed in one AML patient at diagnosis disappeared after complete remission (CR). In addition, Akt phosphorylation was prolonged and increased following IL-3 stimulation in this patient sample. In conclusion, data of this study demonstrate the mutation of the SHIP gene in acute leukemia for the first time and suggest a possible role of the mutation of this gene in the development of acute leukemia. SHIP serves as a tumor suppressor by negatively regulating the PI3K/Akt signaling pathway in hematopoietic cells.

[Mutation analysis of SHIP gene in acute leukemia].

OBJECTIVE: The SH2 domain containing inositol 5'-phosphatase (SHIP) is predominately expressed in hematopoietic cells, and is a crucial negative regulator in the development of hematopoietic cells. This paper is to evaluate the role of the SHIP gene in human leukemogenesis. METHODS: Expression of SHIP gene in bone marrow and/or peripheral blood from 32 patients with acute myeloid leukemia (AML), 9 with acute lymphoblastic leukemia (ALL), as well as human hematopoietic cell lines was analyzed by reverse transcription-polymerase chain reaction (RT-PCR), single strand conformational polymorphism (SSCP) and DNA sequencing. RESULTS: RT-PCR showed that all samples expressed SHIP gene. Mutations of SHIP gene were detected in 7 (22%) of 32 AML patients and one (12%) of 9 ALL patients. Interestingly, two missense mutations that had been observed in a AML patient at diagnosis disappeared after complete remission (CR). In addition, in vitro Akt phosphorylation was prolonged and increased following IL-3 stimulation of this patient's cells. CONCLUSION: Our data demonstrate for the first time the mutation of SHIP gene in acute leukemia and suggest a possible role of the mutation of this gene in the development of acute leukemia. SHIP may serve as a tumor suppressor by negatively regulating the PI3K/Akt signaling pathway in hematopoietic cells.

[In vitro effects of mevastatin on the proliferation and apoptosis in human multiple myeloma cell line U266].

In order to investigate the anti-tumor activity of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors and the mechanism underlying the cell proliferation and apoptosis modulated in myeloma cells, the effects of mevastatin, an HMG-CoA reductase inhibitor, on cell growth, cell cycle progression and apoptosis in U266 human multiple myeloma (MM) cell line in vitro were explored by MTT colorimetric assay, morphologic observation, flow cytometry, DNA gel electrophoresis, and RT-PCR. The results demonstrated that mevastatin inhibited the growth of U266 cells in time- and dose-dependent manners. Cell cycle analysis showed that U266 cells underwent G(0)/G(1) arrest under exposure to mevastatin, but it did not affect p27 expression at both mRNA and protein level. Morphologic observations revealed cytoplasm shrinkage, nuclear condensation and fragmentation in mevastatin-treated cells, and fraction of annexin V(+)PI(-) cells increased significantly in the presence of the agent as determined by flow cytometric assay. In addition, mevastatin caused the collapse of mitochondrial transmembrane potential (Deltapsim), induced DNA fragmentation, and down-regulated the mRNA expression of bcl-2. The growth-inhibitory, cell cycle arresting, and proapoptotic effects of mevastatin in U266 cells could be effectively reversed by the addition of mevalonate (MVA), the immediate endproduct of the reaction catalyzed by HMG-CoA reductase. It is concluded that mevastatin suppresses proliferation by inducing G(0)/G(1) phase arrest and triggering apoptosis via down-regulation of bcl-2 and reduction of Deltapsim, which may be attributed to the inhibition of MVA pathway by mevastatin. Statins including mevastatin may find their future application in the treatment of MM.

Mutation analysis of hematopoietic cell phosphatase gene in acute leukemia.

The hematopoietic cell phosphatase (HCP or SHP-1), the SH2 domain contain protein tyrosine phosphatase, is a crucial negative regulator in the process of hematopoietic cell development, proliferation and receptor-mediated mitogenic signaling pathways, and its mutation is responsible for the over-expansion and inappropriate activation of myelomonocytic population in motheaten mice. The aim of the study was to evaluate the role of the HCP gene in leukemogenesis. Bone marrow and/or peripheral blood from 32 acute myeloid leukemia (AML) patients, 9 acute lymphocytic leukemia (ALL) patients, 8 leukemia cell lines and 50 normal controls were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) based on single strand conformation polymorphism (SSCP) and sequencing. RT-PCR showed that all samples expressed HCP gene, only one missense mutation at codon 225 (AAC to AGC, Asn to Ser) within N-terminal SH2 domain was found in an ALL patient. In addition, four polymorphic base substitutions were detected in codon 69, 85, 86 and 266, respectively. In conclusion, mutation of HCP gene is an infrequent genetic aberration which may only play a role in pathogenesis of a small part of leukemia, however, its significance needs to be further clarified.

Low angiogenic potency induced by the implantation of ex vivo expanded CD117(+) stem cells.

Ex vivo expansion of stem cells might be a feasible method of resolving the problem of limited cell supply in cell-based therapy. The implantation of expanded CD34(+) endothelial progenitor cells has the capacity to induce angiogenesis. In this study, we tried to induce angiogenesis by implanting expanded CD117(+) stem cells derived from mouse bone marrow. After 2 wk of culture with the addition of several growth factors, the CD117(+) stem cells expanded approximately 20-fold and had an endothelial phenotype with high expression of CD34 and vascular endothelial-cadherin. However, >70% of these ex vivo expanded cells had a senescent phenotype by beta-galactosidase staining, and their survival and incorporation were poor after implantation into the ischemic limbs of mice. Compared with the PBS injection only, the microvessel density and the percentage of limb blood flow were significantly higher after the implantation of 2 x 10(5) freshly collected CD117(+) cells (P < 0.01) but not after the implantation of 2 x 10(5) expanded CD117(+) cells (P > 0.05). These data indicate that ex vivo expansion of CD117(+) stem cells has low potency for inducing therapeutic angiogenesis, which might be related to the cellular senescence during ex vivo expansion.

[Effects of bcl-2 antisense oligodeoxynucleotide on proliferation and apoptosis of Raji cells].

OBJECTIVE: To study the in vitro antitumor activity of bcl-2 fully phosporothioated antisense oligodeoxynucleotide (bcl-2 ASODN) to malignant lymphoblastic cells. METHODS: Proliferation and apoptosis of Raji cells incubated with bcl-2 ASODN were evaluated by MTT assay, flow cytometry (FCM) and electron microscopy, and the level of bcl-2 protein and mRNA expression were assessed by FCM and RT-PCR, respectively. RESULTS: MTT assay demonstrated that bcl-2 ASODN could partially inhibit the growth of Raji cells. After incubated with ASODN for 48 hours, Raji cells exhibited characteristic morphologic changes of apoptosis, including cytoplasm membrane blebbing, chromatin condensation crescents formation and nuclear fragmentation. The apoptosis rate of Raji cells treated with 20 micromol/L bcl-2 ASON for 72 hrs was 43.86% which is significantly higher than that of control (10.05%). The bcl-2 ASODN induced apoptosis of Raji cells was accompanied by declined expression of bcl-2 mRNA, which decreased to 0.88% at 72 hrs and was significantly lower than that of control (79.54%). CONCLUSION: bcl-2 ASODN induced Raji cells apoptosis by downregulating bcl-2 protein.