Effective Management of Polycythemia Vera With Ropeginterferon Alfa-2b Treatment.

Background: Polycythemia vera (PV) is a myeloproliferative neoplasm. Ropeginterferon alfa-2b is a new-generation polyethylene glycol-conjugated proline-interferon. It is approved for the treatment of PV at a starting dose of 100 µg (50 µg for patients receiving hydroxyurea (HU)) and dose titrations up to 500 µg by 50 µg increments. The study was aimed at assessing its efficacy and safety at a higher starting dose and simpler intra-patient dose escalation. Methods: Forty-nine patients with PV having HU intolerance from major hospitals in China were treated biweekly with an initial dose of 250 µg, followed by 350 µg and 500 µg thereafter if tolerated. Complete hematological response (CHR) was assessed every 12 weeks based on the European LeukemiaNet criteria. The primary endpoint was the CHR rate at week 24. The secondary endpoints included CHR rates at weeks 12, 36 and 52, changes of JAK2V617F allelic burden, time to first CHR, and safety assessments. Results: The CHR rates were 61.2%, 69.4% and 71.4% at weeks 24, 36, and 52, respectively. Mean allele burden of the driver mutation JAK2V617F declined from 58.5% at baseline to 30.1% at 52 weeks. Both CHR and JAK2V617F allele burden reduction showed consistent increases over the 52 weeks of the treatment. Twenty-nine patients (63.0%) achieved partial molecular response (PMR) and two achieved complete molecular response (CMR). The time to CHR was rapid and median time was 5.6 months according to central lab results. The CHRs were durable and median CHR duration time was not reached at week 52. Mean spleen index reduced from 55.6 cm2 at baseline to 50.2 cm2 at week 52. Adverse events (AEs) were mostly mild or moderate. Most common AEs were reversible alanine aminotransferase and aspartate aminotransferase increases, which were not associated with significant elevations in bilirubin levels or jaundice. There were no grade 4 or 5 AEs. Grade 3 AEs were reversible and manageable. Only one AE led to discontinuation. No incidence of thromboembolic events was observed. Conclusion: The 250-350-500 µg dosing regimen was well tolerated and effectively induced CHR and MR and managed spleen size increase. Our findings demonstrate that ropeginterferon alfa-2b at this dosing regimen can provide an effective management of PV and support using this dosing regimen as a treatment option.

ASXL1 mutations in Chinese patients with essential thrombocythemia.

Essential thrombocythemia (ET) is characterized by thrombotic and hemorrhagic events. The association of clinical characteristics of Chinese ET patients and additional sex combs like 1 (ASXL1) mutations in these patients has remained to be elucidated. In the present study, 72 newly diagnosed Chinese ET patients were enrolled to determine ASXL1 mutations. Mutations in ASXL1, Janus kinase (JAK)2, calreticulin (CALR) and myeloproliferative leukemia (MPL) genes were detected using Sanger sequencing, and data were statistically analyzed. The frequencies of ASXL1, JAK2 V617F, CALR and MPL W515 mutations in ET patients were 19.4% (14/72), 29.2% (21/72), 31.9% (23/72) and 0% (0/72), respectively. Of note, 28 ET patients (38.9%) were negative for JAK2, CALR and MPL mutations; these patients were classified as triple-negative (TN). The frequency of ASXL1 mutations in patients with JAK2 V617F, CALR and TN mutations was 23.8% (5/21), 21.7% (5/23) and 14.3% (4/28), respectively. ASXL1-mutant patients exhibited significant propensities for thrombotic events compared with the ASXL1 wild-type (wt) cohort (42.9 vs. 12.1%; P=0.021). In addition, JAK2 V617F-mutant patients had a higher mean age compared with CALR-mutant (64.76 vs. 52.96 years; P=0.008) or TN patients (64.76 vs. 51.14 years; P=0.002). Furthermore, more white blood cells in the peripheral blood (PB) were observed in JAK2 V617F-mutant patients compared with those in TN patients (12.40 vs. 8.20×109/l; P=0.02). In addition, CALR-mutant patients exhibited more platelets (PLT) in PB than JAK2 V617F-mutant patients (787.91 vs. 562.17×109/l; P=0.047). TN patients had a significantly lower incidence of clinical symptoms, including dizziness, palpitation and chest congestion compared with CALR- or JAK2 V617F-mutant patients (14.1 vs. 39.1%; P=0.043 and 14.1 vs. 38.1%; P=0.050). No significant difference in progression-free survival was observed between ASXL1-mutant and ASXL1-wt patients (P=0.590). In conclusion, ASXL1-mutant ET patients are prone to experiencing thrombotic events. There was no significant difference in the occurrence of thrombotic events among CARL-mutant, JAK2 V617F-mutant and TN patients. Furthermore, ASXL1-mutant/TN patients exhibited a higher number of PLT than ASXL1/JAK2 V617F-double mutant patients. Therefore, ASXL1 mutations may be a risk factor for the occurrence of thrombotic events in ET patients.

[An in vitro dendritic cells-induced T lymphocytes cytotoxicity study activated by thaw frozen K562 lysates antigen in chronic myeloid leukemia].

OBJECTIVE: To investigate the anti-chronic myeloid leukemia (CML) effect of cytotoxicity T lymphocytes (CTL) activated by dendritic cells (DC) pulsed with freeze thaw K562 lysates antigen. METHODS: DC were achieved by healthy donors peripheral blood monocytes which were induced by granulocyte-macrophage colony stimulating factor (GM-CSF) and IL-4. On the sixth day, these cells were collected. One part of them was used to prove that they were DC from morphology and phenotypes. The other part was pulsed with K562 lysates and the lysate-loaded DC were compared with immature DC from phenotypes. The expression of IL-12 and IFNgamma in supernatant, the mixed lymphocytes reaction and the specific cytotoxicity against leukemia cells were tested. RESULTS: Freeze thaw K562 lysate up-regulated the expression of various differentiation antigens of DC, such as CD(1a) (27.40 +/- 5.00)% vs (15.40 +/- 2.34)%, CD(80) (61.35 +/- 5.35)% vs (42.00 +/- 2.77)%, CD(83) (93.30 +/- 3.48)% vs (25.15 +/- 4.02)%, CD(86) (85.25 +/- 4.39)% vs (37.25 +/- 3.20)%, CD(40) (89.80 +/- 7.18)% vs (35.95 +/- 4.06)% and HLA-DR (49.50 +/- 5.45)% vs (17.15 +/- 3.61)%. Simultaneously, the expression of IL-12 rose after DC were loaded with tumor lysates after 24 hours (P < 0.05). The T cells from healthy donors and CML patients, proliferated by antigen loaded DC, could induce IFNgamma increase (P < 0.01). The proliferation of T cells had distinct relation with the time of antigen loaded with DC. These T cells had specific cytotoxicity against K562 and HLA partial matching CML cells. CONCLUSIONS: DC pulsed with K562 lysates can stimulate T cells, and can keep high immunocompetence with specific cytotoxicity against K562.

[A study on the expression of myeloid cell leukemia 1 proteins and survivin and their relation with B cell apoptosis in non-Hodgkin's lymphoma].

OBJECTIVE: To explore the expression of myeloid cell leukemia 1 (MCL-1) proteins and survivin and its correlation with cell apoptosis as well as with the development and progression of B cell non-Hodgkin's lymphoma (B-NHL). METHODS: TdT-mediated dUTP nick end labeling and immunohistochemistry were used to study cell apoptosis and expression of MCL-1 proteins and survivin proteins in 43 patients with B-NHL and 10 with reactive hyperplasia (RH) lymphoid tissue. RESULTS: The positive rate of MCL-1 proteins and survivin proteins was 58.1% (25/43) and 69.8% (30/43) respectively. The expression of MCL-1 proteins was not detected in RH lymphoid tissue, but that of survivin was detected in 10.0% (1/10). The expression of MCL-1 proteins in aggressive B-NHL was higher than that in indolent B-NHL (70.0 % vs 30.8 %, P < 0.05). The expression of survivin in aggressive B-NHL was also higher than that in indolent B-NHL (80.0% vs 46.2%, P < 0.05). Apoptotic index (AI) was not correlated positively with the expression of MCL-1, but correlated positively with the expression of survivin (r = 0.429, P < 0.01). MCL-1 and survivin were correlated positively in B-NHL (r = 0.598, P < 0.001). CONCLUSIONS: MCL-1 proteins as family member of BCL-2 have no influence on apoptosis but survivin may participate in the regulation mechanism of B-NHL apoptosis. It is indicated that the two proteins with a close relationship may take part in the development and progression of B-NHL.

Naringenin suppresses K562 human leukemia cell proliferation and ameliorates Adriamycin-induced oxidative damage in polymorphonuclear leukocytes.

Treatments for leukemia remain unsatisfactory. Conventional chemotherapy agents that aim to kill tumor cells may also damage normal cells and thus result in severe side-effects. Naringenin, a natural polyphenolic compound with antioxidant effects, has been revealed to have significant antitumor effects with low toxicity in preliminary studies. Thus, it is considered as one of the most promising flavonoids in the treatment of leukemia. In the present study, the effects of naringenin on the K562 human leukemia cell line and the underlying mechanisms were explored in vitro. In addition, human peripheral blood polymorphonuclear leukocytes (PMNs) were used as a normal control in order to evaluate the effects of naringenin on normal granulocytes and in the mediation of Adriamycin (ADM)-induced oxidative damage. The results revealed that K562 proliferation was significantly inhibited by naringenin in a time- and concentration-dependent manner; however, minimal cytotoxic effects were observed in PMNs when naringenin was used at concentrations <400 µmol/l. Morphological changes indicative of apoptosis were observed in naringenin-treated K562 cells. Flow cytometric analysis indicated that the K562 cells were arrested in the G0/G1 phase of the cell cycle with a significantly upregulated rate of apoptosis. Furthermore, in the naringenin-treated K562 cells, the labeling index of proliferating cell nuclear antigen was observed to be increased by immunochemical staining, the mRNA and protein expression levels of p21/WAF1 were strongly upregulated in reverse transcription-polymerase chain reaction and western blot analyses, whereas p53 gene expression was not significantly changed. In PMNs to which naringenin (50~80 µmol/l) was added 1 h subsequent to ADM, the cell damage induced by ADM was significantly reduced, coincident with reductions in the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and increases in the activity of superoxide dismutase and glutathione peroxidase. However, the cytotoxic effect of ADM in K562 cells was not significantly altered by naringenin, and the oxidative stress indices in K562 cells remained stable. In conclusion, the present study revealed the promising value of naringenin in leukemia treatment. Naringenin demonstrated a significant inhibitory effect on the growth of K562 cells but not on normal PMNs. Furthermore, naringenin protected PMNs from ADM-induced oxidative damage at low concentrations. Cell cycle arrest and apoptosis-inducing effects, achieved through p53-independent p21/WAF1 upregulation, are likely to be the mechanism of the antileukemic effects of naringenin, and the protective effect against ADM chemotherapy-induced damage in PMNs may be due to the antioxidant capability of this agent at low concentrations.

[Reversal of multidrug resistance of the drug resistant human multiple myeloma cell line MOLP-2/R by curcumin and its relation with FA/BRCA pathway].

OBJECTIVE: To investigate the reverse effect of mutidrug resistance of curcumin combined with melphalan on the mutidrug-resistant human multiple myeloma cell line MOLP-2/R and the relation with FA/BRCA pathway. METHODS: The inhibitory effects of the drugs on the growth of MOLP-2/R cells were determined by MTT assay. Cell cycle analysis, intracellular drug concentration and apoptosis were assayed by flow cytometry. The expression of FANCD2 monoubiquitination was determined by Western blot analysis. RESULTS: Co-administration of curcumin and melphalan had an synergistic inhibitory effects on the proliferation, IC50 of melphalan with 10 micromol/L curcumin reduced from 45.5 micromol/L to 19 micromol/L in MOLP-2/R cells. The apoptosis percentage of MOLP-2/R cells was significantly increased from (23.3 +/- 0.6)% to (52.6% +/- 0.8)% by the treatment of melphalan 20 micromol/L plus curcumin 10 micromol/L with the increased percentage of cells in the G2/M phase (from 9.1% to 18.5%) and enhanced intracellular drug concentration of MOLP-2/ R cells (from 15.2 +/- 0.3 to 21.4 +/- 0.8 ). The effects were accompanied with inhibition of FA/BRCA pathway by down regulation of FANCD2 protein monoubiquitination. CONCLUSION: Curcumin combined with melphalan results in synergistic effects and reverses multiple drug resistance of MOLP-2/R cells effectively. The inhibition of FA/BRCA pathway may be the mechanism.

[Protection against doxorubicin-induced oxidative damage in normal blood cells by naringenin].

The objective of this study was to investigate the protection by naringenin against doxorubicin-induced oxidative damage in normal blood cells. Inhibiting effects of naringenin, doxorubicin and naringenin combined with doxorubicind on K562 cells and polymorphonuclear leukocytes were detected with MTT method, the level of reactive oxygen species (ROS) and lipid peroxidation (MDA), the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were examined with spectrophotometric method in the K562 cells and polymorphonuclear leukocytes. The results indicated that the proliferation of K562 cells was not inhibited by the cytotoxicity of doxorubicin in combination of naringenin with doxorubicin. As compared with the doxorubicin, the addition of naringenin after doxorubicin for 1 hour, the levels of reactive oxygen species (ROS) and lipid peroxidation (MDA) obviously decreased, the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) obviously increased in the polymorphonuclear leukocytes, but these were not changed obviously in K562 cells. It is concluded naringenin can protect against doxorubicin-induced oxidative damage in normal blood cells. The mechanism of naringenin may be elevating activities of antioxidant enzyme and degrading oxidative production level in normal blood cells, and meanswhile decreasing level of oxidative products.

[Mechanism of ligustrazine promoting hematopoietic reconstitution in syngenic bone marrow transplanted mice].

The objective of this study was to investigate the effect of ligustrazine on the expression of stem cell factor mRNA (SCF) in bone marrow tissue and explore the mechanism of hematopoietic reconstitution after bone marrow transplantation (BMT). The colony forming unit of spleen (CFU-S) were counted, the survival rate at days 7, 14 and 21 after BMT were measured, as well as the expression level of SCF mRNA was detected by RT-PCR. The results showed that in ligustrazine group CFU-S counts on day 10 and survival rate, expression level of SCF mRNA on day 7, 14 and 21 after BMT were higher than that in the control group (p < 0.01 or p < 0.05). In conclusion, ligustrazine promotes the recovery of hematopoietic cells in bone marrow, enhances the repair of bone marrow microvessels, and then improves bone marrow microenvironment and promotes hematopoietic reconstitution.

[Relation of apoptosis of K562 cells induced by naringenin in vitro to enzyme activity changes of caspase-3 and caspase-8 and expression of FAS/FASL proteins].

The objective of this study was to investigate the apoptosis-inducing effect and underlying mechanism of naringenin (NGEN) on K562 cells in vitro. The inhibition of NGEN on K562 cells was evaluated by means of MTT assay so as to observe the cytotoxicity of NGEN; The morphological changes of the cells treated by NGEN were observed by transmission electron microscope; cell apoptosis rate influenced by NGEN was assessed by flow cytometry; the enzyme activity changes of caspase-3 and caspase-8 in the process of NGEN-induced K562 apoptosis were detected by Caspase Colorimetric Assay Kit; immunohistochemistry technique was used to detect FAS, FASL protein expression in K562 cells. The results showed that the growth of cells was inhibited by NGEN in dose-and time-dependent manners (p<0.05); NGEN-induced K562 cells apoptosis and sub-G1 peak was observed; some typically early and final phase changes of cell apoptosis were revealed under transmission electron microscope; the enzyme activity of caspase-3 and caspase-8 and the expression of FAS remarkably increased, meanwhile the expression of FASL was down-regulated (p<0.05). It is concluded that NGEN exerts anti-cancer effect by inducing K562 cell apoptosis, and the regulation of the expression of FAS and FASL. The caspase-3 and caspase-8 co-pathway brings about one of the mechanisms.

[Construction of FANCA mutant protein from Fanconi anemia patient and analysis of its function].

OBJECTIVE: To study FANCA protein expression in Fanconi anemia patient's (FA) cells and explore its function. METHODS: FANCA protein expression was analyzed in 3 lymphoblast cell lines derived from 3 cases of type A FA (FA-A) patients using Western blot. Nucleus and cytoplasm localization of FANCA protein was analyzed in one case of FA-A which contained a truncated FANCA (exon 5 deletion). The FANCA mutant was constructed from the same patient and its interaction with FANCG was evaluated by mammalian two-hybrid (M2H) assay. RESULTS: FANCA protein was not detected in the 3 FA-A patients by rabbit anti-human MoAb, but a truncated FANCA protein was detected in 1 of them by mouse anti-human MoAb. The truncated FANCA could not transport from cytoplasm into nucleus. The disease-associated FANCA mutant was defective in binding to FANCG in M2H system. CONCLUSIONS: FANCA proteins are defective in the 3 FA-A patients. Disfunction of disease-associated FANCA mutant proved to be the pathogenic mutations in FANCA gene. Exon 5 of FANCA gene was involved in the interaction between FANCA and FANCG.

[Expression of survivin and P63 protein in B cell non-Hodgkin's lymphoma and their effects on cell apoptosis and proliferation].

The study was aimed to explore the possible roles of survivin and P63 protein in the development and progression of B cell non-Hodgkin's lymphoma (B-NHL) and their relation with cell apoptosis and proliferation. TdT-mediated dUTP nick end labeling (TUNEL) and immunohistochemistry were used to detect the survivin and P63 protein expression, cell apoptosis and proliferating cell nuclear antigen (PCNA) level in 43 cases of B-NHL and 10 cases of reactive hyperplasia lymphoid (RHL) tissues. The results indicated that the positive rates of survivin and P63 protein expression were 69.8% (30/43) and 82.7% (30/43) respectively. The expression of survivin and P63 protein was 10% (1/10) and 40% (4/10) in RHL tissues of 10 cases. The expression of survivin in aggression B-NHL was higher than that in indolent B-NHL (83.3% vs 46.2%, P < 0.01). The expression of P63 proteins in aggressive B-NHL was higher than that in indolent B-NHL (86.7% vs 76.9%, P > 0.05). Apoptotic index (AI) and proliferation index (PI) correlated positively with expression of survivin (r = 0.429, P < 0.01; r = 0.348, P < 0.01), and so do with expression of P63 proteins (r = 0.451, P < 0.01; r = 0.369, P < 0.05). In addition, AI and PI were positively related (r = 0.598, P < 0.001). It is concluded that survivin may participate in the regulation mechanism of B-NHL cell apoptosis and proliferation, P63 as an oncogene enhances proliferation and takes part in the development of B-NHL. There may be a close relationship between survivin and P63 protein in the regulation of lymphocyte proliferative kinetics.