[The Effect of TCP1 Expression on the Proliferation and the Accumulation of Intracellular Drug of HL60/A and HL60 Cell and Its Mechanism].

OBJECTIVE: To investigate the effect of TCP1 expression on the proliferation and the accumulation of intracellular drug of HL60/A and HL60 cells and its possible molecular mechanism. METHODS: Lentiviral transfection technology was used to construct HL60/A and HL60 cells with knocked down or overexpressed TCP1 and their control cells. The efficiency of knockdown and overexpression was evaluated by Western blot. The cell proliferation was detected by CCK-8 assay. The intracellular drug accumulation was detected by laser confocal detection and flow cytometry. The expression levels of MRP1, P-gP and p-AKT were evaluated by flow cytometry and Western blot. RESULTS: After TCP1 was knocked down,the proliferation ability of HL60/A cells was significantly reduced, the accumulation of intracellular drug was significantly increased and the expression of MRP1 and P-gP protein were decreased. After TCP1 was overexpressed, the proliferation ability of HL60 was significantly increased, the accumulation of intracellular drug was significantly decreased and the expression of MRP1 and P-gP protein were increased. Intervention of LY294002 significantly antagonized the promotion on cell proliferation, the inhibition on intracellular drug accumulation and the expression of MRP1 and P-gP mediated by TCP1 overexpressing in HL60 cells. CONCLUSION: TCP1 can promote cell proliferation, improve the expression of MRP1 and P-gP by activating PI3K/AKT signal, and reduce intracellular drug accumulation.

A novel prognostic nomogram for adult acute lymphoblastic leukemia: a comprehensive analysis of 321 patients.

The cure rate of acute lymphoblastic leukemia (ALL) in adolescents and adults remains poor. This study aimed to establish a prognostic model for ≥14-year-old patients with ALL to guide treatment decisions. We retrospectively analyzed the data of 321 ALL patients between January 2017 and June 2020. Patients were randomly (2:1 ratio) divided into either the training or validation set. A nomogram was used to construct a prognostic model. Multivariate Cox analysis of the training set showed that age > 50 years, white blood cell count > 28.52×109/L, and MLL rearrangement were independent risk factors for overall survival (OS), while platelet count >37×109/L was an independent protective factor. The nomogram was established according to these independent prognostic factors in the training set, where patients were grouped into two categories: low-risk (≤13.15) and high-risk (>13.15). The survival analysis, for either total patients or sub-group patients, showed that both OS and progression-free survival (PFS) of low-risk patients was significantly better than that of high-risk patients. Moreover, treatment analysis showed that both OS and progression-free survival (PFS) of ALL with stem cell transplantation (SCT) were significantly better than that of ALL without SCT. Further stratified analysis showed that in low-risk patients, the OS and PFS of patients with SCT were significantly better than those of patients without SCT. In contrast, in high-risk patients, compared with non-SCT patients, receiving SCT can only significantly prolong the PFS, but it does not benefit the OS. We established a simple and effective prognostic model for ≥ 14-year-old patients with ALL that can provide accurate risk stratification and determine the clinical strategy.

IL-22-dependent dysbiosis and mononuclear phagocyte depletion contribute to steroid-resistant gut graft-versus-host disease in mice.

Efforts to improve the prognosis of steroid-resistant gut acute graft-versus-host-disease (SR-Gut-aGVHD) have suffered from poor understanding of its pathogenesis. Here we show that the pathogenesis of SR-Gut-aGVHD is associated with reduction of IFN-γ+ Th/Tc1 cells and preferential expansion of IL-17-IL-22+ Th/Tc22 cells. The IL-22 from Th/Tc22 cells causes dysbiosis in a Reg3γ-dependent manner. Transplantation of IFN-γ-deficient donor CD8+ T cells in the absence of CD4+ T cells produces a phenocopy of SR-Gut-aGVHD. IFN-γ deficiency in donor CD8+ T cells also leads to a PD-1-dependent depletion of intestinal protective CX3CR1hi mononuclear phagocytes (MNP), which also augments expansion of Tc22 cells. Supporting the dual regulation, simultaneous dysbiosis induction and depletion of CX3CR1hi MNP results in full-blown Gut-aGVHD. Our results thus provide insights into SR-Gut-aGVHD pathogenesis and suggest the potential efficacy of IL-22 antagonists and IFN-γ agonists in SR-Gut-aGVHD therapy.

Tolerogenic anti-IL-2 mAb prevents graft-versus-host disease while preserving strong graft-versus-leukemia activity.

Donor T cells mediate both graft-versus-leukemia (GVL) activity and graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (allo-HCT). Development of methods that preserve GVL activity while preventing GVHD remains a long-sought goal. Tolerogenic anti-interleukin-2 (IL-2) monoclonal antibody (JES6-1) forms anti-IL-2/IL-2 complexes that block IL-2 binding to IL-2Rß and IL-2Rγ on conventional T cells that have low expression of IL-2Rα. Here, we show that administration of JES6 early after allo-HCT in mice markedly attenuates acute GVHD while preserving GVL activity that is dramatically stronger than observed with tacrolimus (TAC) treatment. The anti-IL-2 treatment downregulated activation of the IL-2-Stat5 pathway and reduced production of granulocyte-macrophage colony-stimulating factor (GM-CSF). In GVHD target tissues, enhanced T-cell programmed cell death protein 1 (PD-1) interaction with tissue-programmed cell death-ligand 1 (PD-L1) led to reduced activation of protein kinase-mammalian target of rapamycin pathway and increased expression of eomesodermin and B-lymphocyte-induced maturation protein-1, increased T-cell anergy/exhaustion, expansion of Foxp3-IL-10-producing type 1 regulatory (Tr1) cells, and depletion of GM-CSF-producing T helper type 1 (Th1)/cytotoxic T cell type 1 (Tc1) cells. In recipient lymphoid tissues, lack of donor T-cell PD-1 interaction with tissue PD-L1 preserved donor PD-1+TCF-1+Ly108+CD8+ T memory progenitors and functional effectors that have strong GVL activity. Anti-IL-2 and TAC treatments have qualitatively distinct effects on donor T cells in the lymphoid tissues, and CD8+ T memory progenitor cells are enriched with anti-IL-2 treatment compared with TAC treatment. We conclude that administration of tolerogenic anti-IL-2 monoclonal antibody early after allo-HCT represents a novel approach for preventing acute GVHD while preserving GVL activity.

Sepsis progression monitoring via human serum fibronectin detection based on sandwich-type electrochemical immunosensor.

Sepsis has always been a severe clinical problem in critical care medicine due to its rather high mortality and poor prognosis. The current study reported for the first time a practical immunosensor for fibronectin (FN) detection in human serum by electrochemistry. A simple but robust sandwich-type strategy was employed without any complex design or material modifications, which exhibited a linear calibration plot over the 15.625-500 ng/mL concentration range and a detection limit of 15 ng/mL. The results showed that the proposed strategy displayed an excellent selectivity against other non-target substances in human serum, a higher accuracy and a better stability when compared with the traditional enzyme-linked immunosorbent assay (ELISA) in detecting the same or mixed serum from 21 healthy subjects. Furthermore, the proposed electrochemical immunosensor successfully monitored the level of serum FN at various time points in five septic patients during the treatment. These findings demonstrate that the proposed strategy is highly sensitive and accurate in monitoring sepsis progress and has significant clinical improvements over the ELISA methodology, signifying a great potential of a commercial kit.

[Expression and Clinical Significances of HGFA, Matriptase, HAI-1 and HAI-2 in Acute Myeloid Leukemia].

OBJECTIVE: To investigate the expression and clinical significances of HGFA, Matriptase, HAI-1 and HAI-2 in patients with acute myeloid leukemia (AML). METHODS: The bone marrow samples from 91 AML patients, 41 AML patients in complete remission, and 32 normal controls were collected. Real time fluorescence quantitative RT-PCR (qRT-PCR) was used to detect the mRNA expressions levels of HGFA, Matriptase, HAI-1, HAI-2 . The expressions of these genes were compared among AML untreated group, the complete remission group and the healthy control group. The correlation of their expression with clinical characteristics was analyzed. RESULTS: The level of HGFA in the AML untreated group was higher than that in the healthy control group（P<0.05）, while the HAI-2 mRNA level was lower than that in the healthy control group（P<0.05）. The mRNA levels of HAI-1 and Matriptase were not changed significantly in all groups. The HAI-2 mRNA expression level was significantly lower in the high white blood cell group (P<0.05). CONCLUSION: The abnormal activation of HGF/c-Met signaling system in AML may result from the increase of HGFA expression and the decrease of HAI-2 expression of the upstream regulatory factors.

2'-Fluoro ribonucleic acid modified DNA dual-probe sensing strategy for enzyme-amplified electrochemical detection of double-strand DNA of PML/RARα related fusion gene.

In the study, a novel sensing strategy based on dual-probe mode, which involved two groups of 2'-fluoro ribonucleic acid (2'-F RNA) modified probes, was designed for the detection of synthetic target double-strand DNA (dsDNA) of PML/RARα fusion genes in APL. And each pair of probes contained a thiolated capture probe (C1 or C2) immobilized on one of electrode surfaces in the dual-channel electrochemical biosensor and a biotinylated reporter probe (R1 or R2). The two groups of 2'-F RNA modified probes were separately complementary with the corresponding strand (Sa or Sb) from target dsDNA in order to prevent renaturation of target dsDNA. Through flanking target dsDNA, two "sandwitch" complexes (C1/Sa/R1 and C2/Sb/R2) were separately shaped by capture probes (C1 and C2) and free reporter probes (R1 and R2) in hybridization solution on the surfaces of different electrodes after the thermal denaturation. The biotin-modified enzyme which produced the measurable electrochemical current signal was localized to the surface by affinity binding between biotin with streptavidin. Under the optimal condition, the biosensor was able to detect 84 fM target dsDNA and showed a good specificity in PBS hybridization solution. Otherwise, the investigations of the specificity and sensitivity of the biosensor were carried out further in the mixed hybridization solution containing different kinds of mismatch sequences as interference background. It can be seen that under a certain interference background, the method still exhibited excellent selectivity and specificity for the discrimination between the fully-complementary and the mismatch sequences. The results of our research laid a good basis of further detection research in practical samples.

Expression and role of granulocyte macrophage colony-stimulating factor receptor (GM-CSFR) and granulocyte colony-stimulating factor receptor (G-CSFR) on Ph-positive acute B lymphoblastic leukemia.

OBJECTIVE: We observed that ph + ALL patients administrated with recombinant human G-CSF (rhG-CSF) after intense chemotherapy have presented a trend of disease relapse. Thus, we aim to thoroughly investigate the expression and role of GM-CSFR and G-CSFR on ph + ALL patients. METHOD: SUP-B15, BALL-1 and primary leukemia cells were used in this study. Transcript levels were analyzed by quantitative PCR while cell viability was measured using a CCK-8 assay. Flow cytometry was used to assess the different stages of cell cycle. RESULTS: We found that the mRNA expression levels of GM-CSFR and G-CSFR were higher in patients with ph + ALL, as well as in SUP-B15 cells. rhG-CSF was also observed to promote the viability of SUP-B15 cells while inversely inhibiting BALL-1 cell viability. In addition, we also determined that rhG-CSF (100 ng/ml) decreased the sensitivity of SUP-B15 cells to imatinib and nilotinib, while the results were exactly the contrary for dasatinib. CONCLUSION: We demonstrated high expression levels of GM-CSFR and G-CSFR, as well as their promotable role for viability in ph + ALL cells. We further found that rhG-CSF influenced the sensitivity of SUP-B15 cells to TKIs.

PD-L1 interacts with CD80 to regulate graft-versus-leukemia activity of donor CD8+ T cells.

Programmed death ligand-1 (PD-L1) interacts with programmed death-1 (PD-1) and the immunostimulatory molecule CD80 and functions as a checkpoint to regulate immune responses. The interaction of PD-L1 with CD80 alone has been shown to exacerbate the severity of graft-versus-host disease (GVHD), whereas costimulation of CD80 and PD-1 ameliorates GVHD. Here we have demonstrated that temporary depletion of donor CD4+ T cells early after hematopoietic cell transplantation effectively prevents GVHD while preserving strong graft-versus-leukemia (GVL) effects in allogeneic and xenogeneic murine GVHD models. Depletion of donor CD4+ T cells increased serum IFN-γ but reduced IL-2 concentrations, leading to upregulation of PD-L1 expression by recipient tissues and donor CD8+ T cells. In GVHD target tissues, the interactions of PD-L1 with PD-1 on donor CD8+ T cells cause anergy, exhaustion, and apoptosis, thereby preventing GVHD. In lymphoid tissues, the interactions of PD-L1 with CD80 augment CD8+ T cell expansion without increasing anergy, exhaustion, or apoptosis, resulting in strong GVL effects. These results indicate that the outcome of PD-L1-mediated signaling in CD8+ T cells depends on the presence or absence of CD4+ T cells, the nature of the interacting receptor expressed by CD8+ T cells, and the tissue environment in which the signaling occurs.

Hepatocyte growth factor promotes proliferation, invasion, and metastasis of myeloid leukemia cells through PI3K-AKT and MAPK/ERK signaling pathway.

This study aims to investigate effects of HGF expression on biological behaviors of Kasumi-1 and HL60. Expression of HGF and c-Met gene were detected using qRT-PCR. Short hairpin RNA (shRNA) was used to reduce HGF expression. Silencing effect of shRNA was verified by qRT-PCR and western blot. Cell reproductive capacity, cell clonality and cell cycle (apoptosis) were detected by CCK-8, clone formation, flow cytometry (FCM), respectively. Cell adhesion, cell invasion ability and cell proliferation were also examined. Changes of PI3K-AKT, MAPK/ERK signaling factors were detected by western blot. HGF and c-Met expression in first-vist AML group was significantly higher than in AML-relief and normal control group. HGF shRNA can inhibit cell proliferation, inhibit cloning ability. Compared with control group, apoptosis ratios of Kasumi-1 and HL60 cell in interference groups were significantly higher. After shRNA interference, the number of adherent cells and transmembrane cells were significantly decreased compared with control group. Meanwhile, shRNA also down-regulated Bad, Bcl-XL, Bcl-2, CDK1, Cyclin B, MMP2, MMP9, and up-regulated cleaved caspase9, cleaved caspase3, cleaved PARP, Bax, and P21. Moreover, phosphorylated c-Met, AKT, Erk, and mTOR were also reduced. In conclusion, HGF and c-Met gene highly expressed among first-visit AML patients, but decreased after relief treatment. HGF may promote proliferation, invasion, and metastasis of AML cells through PI3K-AKT and MAPK/ERK signaling pathway. Therefore, proliferation and invasion ability of AML cell can be inhibited by down-regulating HGF gene to retardate cell in G2/M stage.

[Expression of CD131 Gene in Acute Myeloid Leukemic Cells].

OBJECTIVE: To detect the expression level and the mutantion of CD131 in acute myeloid leukemic (AML) cells, and to analyze the relationship of CD131 expression level with clinical features. METHODS: The peripheral blood mononuclear cells (PBMNC) from 44 AML patients and 25 healthy donors were collected, and the expression level of CD131 mRNA was detected by RT-PCR. The full length coding sequence of CD131 from 15 patients and 5 healthy donors was amplified by RT-PCR, and linked to pGEM-T vector to clone TA, 10 positive recombinant clones of each sample were analyzed by DNA sequencing. The AML patients were divided into CD131 negative and CD131 positive groups according the expression level of CD131, and white blood cell counts, CD34(+) cells percentage, complete remission rate of patients were compared. RESULTS: CD131 was expressed at a lower level in AML than that in healthy donor. Five kinds of CD131 mutantions could be detected in both AML and healthy donor groups, but the mutation rate in AML (75.33%) was higher than that in healthy donors (18.0%). CD131 negative group showed a higher CD34(+) cells percentage (69.1% ± 20.8%), and lower complete remission rate (33.3%) than that in CD131 positive group (69.1% ± 20.8%, 33.3%). No statistically significant difference of WBC counts was found between 2 groups. CONCLUSION: CD131 is expressed at a low level and shows high frequency of mutation in acute myeloid leukemic cells. CD131 negative AML correlats with high proportion of CD34(+) cells, and showed insensitive to chemotherapy.

[Expression of Hydrodynamic Injection-mediated PD-L1 in Myeloablative Conditioning Mouse Model].

OBJECTIVE: To establish the mouse model for the expression of PD-L1 by hydrodynamic injection and to study the effects of myeloablative conditioning on hydrodynamic injection-mediated PD-L1 expression. METHODS: Plasmid amplification, hydrodynamic injection, collagenase perfusion, real time PCR, ELISA and flow cytometry were applied to test the expression and function of PD-L1. Also, animal models were set up to test the effects of chemical or radiactive myeloablative conditioning on hydrodynamic injection-mediated PD-L1 expression. RESULTS: The expression of PD-L1 mRNA and protein could be detected as early as 8 h after hyrodynamic injection and reached peak expression by 24 h, and returned to baseline level by 7 d after injection. Serum PD-L1 level reached to 100 µg/ml as early as 24 h after injection and plateaued at 7 d after injection. Serum PD-L1 persisted for 3 weeks and declined to baseline after 1 month of hydrodynamic injection. The PD-L1 function induced by hydrodynamic injection was consistent with literature reports. At each time point, the PD-L1 expression was not different significantly between the myeloablative conditioning group and control group; the mice transfected with PD-L1 showed a higher survival rate than that in control group. CONCLUSION: Myeloablative conditioning does not affect hydrodynamic injection-mediated PD-L1 expression, indicating that the PD-L1 can be used in HSCT mouse model.

Dual-probe electrochemical DNA biosensor based on the "Y" junction structure and restriction endonuclease assisted cyclic enzymatic amplification for detection of double-strand DNA of PML/RARα related fusion gene.

Taking advantage of "Y" junction structure and restriction endonuclease assisted cyclic enzymatic amplification, a dual-probe electrochemical DNA (DE-DNA) biosensor was designed to detect double-stranded DNA (dsDNA) of acute promyelocytic leukemia (APL) related gene. Two groups of detection probes were designed, and each group was composed of a biotinylated capture probe and an assisted probe. They were separately complementary with two strands of target dsDNA in order to prevent the reannealing of the two separate strands from target dsDNA. First, thiol functionalized capture probes (C1 and C2) were severally assembled onto two different gold electrodes, followed by hybridizing with target dsDNA (S1a-S1b) and assistant probes to form two Y-junction-structure ternary complexes. Subsequently, restriction sites on the ternary complexes were digested by Rsa I, which can release S1a, S1b and biotins from the electrode surfaces. Meanwhile, the released S1a and S1b can further hybridize with the unhybridized corresponding detection probes and then initiate another new hybridization-cleavage-separation cycle. Finally, the current signals were produced by the enzyme-catalyzed reaction of streptavidin-horse reddish peroxidase (streptavidin-HRP). The distinct difference in current signals between different sequences allowed detection of target dsDNA down to a low detection limit of 47 fM and presented excellent specificity with discriminating only a single-base mismatched dsDNA sequence. Moreover, this biosensor was also used for assay of polymerase chain reaction (PCR) samples with satisfactory results. According to the results, the power of the DE-DNA biosensor as a promising tool for the detection of APL and other diseases.

[Expression of HIF-1α in primary acute myeloid leukemia cells and its relationship with prognosis].

OBJECTIVE: This study was aimed to detect the expression of HIF-1α in acute myeloid leukemia (AML) except acute promyelocyte leukemia (APL) and investigate the relationship of its expression levels with clinical parameters and prognosis. METHODS: The primary AML cells were collected from peripheral blood of 53 newly diagnosed AML patients by using CD3 negative sorting. The expression of HIF-1α was measured by real-time fluorescent quantitative PCR (FQ-PCR) , and the relationship between expression level of HIF-1α and clinical parameters (age, sex, WBC count, clinical typing, prognosis) was analysed according to relative expression level. Furthermore, Western blot was used to detect the protein level of HIF-1α in AML patients with or without extramedullary infiltration. RESULTS: The expression level of HIF-1α did not correlate with age, sex, WBC count, Hb level, Plt count and the percentage of blast. There was no significant difference of HIF-1α expression between different AML subtype based on FAB. The higher level of HIF-1α was found in AML patients who did not get complete remission after one or two courses of chemotherapy, however, the difference was not statistically significant. The relapse rate was higher in AML patients with the higher expression of HIF-1α. In addition, the higher level of HIF-1α mRNA and protein were found in bone marrow of AML patients with extramedullary infiltration (P < 0.01). The negative correlation between HIF-1α and PTEN was observed (r = -0.48, P = 0.001). CONCLUSIONS: Overexpression of HIF-1α are closely related with extramedullary infiltration and prognosis of acute myeloid leukemia, and may be used as an early indicator of extramedullary infiltration and prognosis.

[Expression of G-CSFR IV isoform in adult acute myeloid leukemia and its clinical significance].

This study was aimed to investigate the expression of granulocyte colony-stimulating factor receptor IV(G-CSFR IV) in adult acute leukemia patients and its clinical significance. The bone marrow hematopoietic stem cells from healthy persons were used as controls. The real-time RT-PCR was used to determine the expression level of G-CSFR I-IV in 99 AML, 34 ALL patients and 19 healthy persons. The results showed that the relative expression level of G-CSFR IV/G-CSFR I in AML patients was obviously elevated, as compared with that in ALL patients and controls, while the relative expression level of G-CSFR IV/G-CSFR I in ALL patients showed no statistical difference from controls. The analysis of clinical features and chemotherapeutic efficacy demonstrated that the clinical remission rate in patients with high expression of G-CSFR IV/G-CSFR I was lower than that in patients with low expression. The relative expression level of G-CSFR IV/G-CSFR I was not related with risk stratification from sex, age, blast ratio, FAB typing, chromosome and fusion gene. It is concluded that the abnormal high expression of G-CSFR IV relates with poor prognosis of AML.

The effect to IL-3Ralpha, downstream PI3k/Akt signaling of all-trans retinoic acid and arsenic trioxide in NB4 cells.

All-trans retinoic acid (ATRA) and arsenic trioxide (As2O3) are the classic drugs used for induction therapy of acute promyelocytic leukemia (APL). IL-3Ralpha (CD123) is a specific marker of acute myeloid leukemia stem cells (AML-LSCs). The over-expression of IL-3Ralpha in patients with AML is related to high white blood cells counts, high percentages of blast cells, and poor prognosis. Moreover, in some studies, IL-3Ralpha has been considered a new detection marker of minimal residual disease in the bone marrow from patients with APL. In contrast to ATRA, As2O3 reduces both mRNA and protein expression of IL-3Ralpha and inhibits the activity of PI3K/Akt after 24 h, 48 h, and 72 h of exposure. Furthermore, NB4 cells adhered to the human stroma cell line HS-5 cells were used as an in vitro model of APL cells in the bone marrow microenvironment. Our results demonstrate that adhesion to HS-5 cells up-regulated IL-3Ralpha protein expression and activated the downstream PI3K/Akt signaling pathway in NB4 cells. Compared with ATRA, As2O3 more potently inhibits proliferation of NB4 cells adhered to stroma cells.

Curcumin derivative C817 inhibits proliferation of imatinib-resistant chronic myeloid leukemia cells with wild-type or mutant Bcr-Abl in vitro.

AIM: To find new kinase inhibitors that overcome the imatinib resistance in treatment of chronic myeloid leukemia (CML), we synthesized C817, a novel derivative of curcumin, and tested its activities against wild-type (WT) and imatinib-resistant mutant Abl kinases, as well as in imatinib-sensitive and resistant CML cells in vitro. METHODS: 32D cells harboring WT or mutant Abl kinases (nucleotide binding P-loop mutants Q252H, Y253F, and imatinib contact residue mutant T315I), as well as K562/G01 cells (with whole Bcr-Abl gene amplication) were tested. Kinase activity was measured using Kinase-Glo Luminescent Kinase Assay Platform in recombinant WT and mutant (Q252H, Y253F, and T315I) Abl kinases. Cell proliferation and apoptosis were examined using MTT assay and flow cytometry, respectively. The phosphorylation levels of Bcr-Abl initiated signaling proteins were analyzed using Western blotting. Colony forming units (CFU) growth and long term culture-initiating cells (LTC-ICs) were used to test the effects of C817 on human leukemia progenitor/stem cells. RESULTS: C817 potently inhibited both WT and mutant (Q252H, Y253F, and T315I) Abl kinase activities in a non-ATP competitive manner with the values of IC50 at low nanomole levels. In consistent with above results, C817 suppressed the growth of both imatinib-sensitive and resistant CML cells, including wild-type K562, K562/G01, 32D-T315I, 32D-Q252H, and 32D-Y253F cells with the values of IC50 at low micromole levels. C817 (0.5 or 1 µmol/L) dose-dependently inhibited the phosphorylation of Bcr-Abl and downstream proteins STAT-5 and CrkL in imatinib-resistant K562/G01 cells. Furthermore, C817 significantly suppressed CFU growth and LTC-ICs, implicating that C817 could eradiate human leukemia progenitor/stem cells. CONCLUSION: C817 is a promising compound for treatment of CML patients with Bcr-Abl kinase domain mutations that confer imatinib resistance.

Sequence-specific electrochemical detection of double-strand PCR amplicons of PML/RARα fusion gene in acute promyelocytic leukemia.

A novel electrochemical method for the sequence-specific detection of double-stranded polymerase chain reaction (PCR) products of PML/RARα fusion gene in acute promyelocytic leukemia (APL) was described in detail. Based on a "sandwich" sensing mode involving a pair of locked nucleic acids probes (capture probe and reporter probe), this DNA sensor exhibited excellent selectivity and specificity. The direct and quantitative analysis of double-stranded complementary was firstly performed by our sensor without the use of alkali, helicase enzymes, or denaturants. Finally, combining PCR technique with electrochemical detection scheme, PCR amplicons (191 bp) of the PML/RARα fusion gene were obtained and rapidly identified with a low detection limit of 79 fmol in the 100-µL hybridization system. The results clearly showed the power of sensor as a promising tool for the sensitive, specific, and portable detection of APL and other diseases.

Bovine serum albumin-based probe carrier platform for electrochemical DNA biosensing.

A bovine serum albumin (BSA)-monolayer-based probe carrier platform is shown to improve the performance of a conventional thiolated single-stranded DNA probe self-assembled-monolayer-based electrochemical DNA hybridization biosensor. A detection limit of 0.5 fM can be obtained in a very reproducible manner (relative standard deviation <5%), along with high specificity. The performance of the biosensor can be attributed primarily to the enhanced spatial positioning range and accessibility of the probes on the BSA-based platform. Furthermore, the novel biosensor shows high resistance to nonspecific adsorption of nucleic acid and protein and can be directly employed in detection in biological fluids. These advantages give this simple developed methodology great promise for a wide range of nucleic acid testing.

Prognostic significance of CD44v6/v7 in acute promyelocytic leukemia.

CD44v, especially splice variants containing exon v6, has been shown to be related closely to development of different tumors. High levels of CD44v6/v7 have been reported to be associated with invasiveness and metastasis of many malignancies. The objective of this study was to detect expression of CD44v6-containing variants in patients with acute promyelocytic leukemia (APL) and evaluate the potential of CD44v6/v7 for risk stratification. Reverse transcription polymerase chain reaction (RT-PCR) followed by PCR product purification, ligation into T vectors and positive clone sequencing were used to detect CD44 v6-containing variant isoforms in 23 APL patients. Real-time quantitative PCR of the CD44v6/v7 gene was performed in patients with APL and in NB4 cells that were treated with all-trans retinoic acid (ATRA) or arsenic trioxide (As2O3). Sequencing results identified four isoforms (CD44v6/v7, CD44v6/v8/v10, CD44v6/v8/v9/v10, and CD44v6/v7/v8/v9/v10) in bone marrow mononuclear cells of 23 patients with APL. The level of CD44v6/v7 in high-risk cases was significantly higher than those with low-risk. Higher levels of CD44v6/v7 were found in three patients with central nervous system relapse than in other patients inthe same risk group. Furthermore, in contrast to ATRA, only As2O3 could significantly down-regulate CD44v6/v7 expression in NB4 cells. Our data suggest that CD44v6/v7 expression may be a prognostic indicator for APL.