Translation elongation rate varies among organs and decreases with age.

There has been a surge of interest towards targeting protein synthesis to treat diseases and extend lifespan. Despite the progress, few options are available to assess translation in live animals, as their complexity limits the repertoire of experimental tools to monitor and manipulate processes within organs and individual cells. It this study, we developed a labeling-free method for measuring organ- and cell-type-specific translation elongation rates in vivo. It is based on time-resolved delivery of translation initiation and elongation inhibitors in live animals followed by ribosome profiling. It also reports translation initiation sites in an organ-specific manner. Using this method, we found that the elongation rates differ more than 50% among mouse organs and determined them to be 6.8, 5.0 and 4.3 amino acids per second for liver, kidney, and skeletal muscle, respectively. We further found that the elongation rate is reduced by 20% between young adulthood and mid-life. Thus, translation, a major metabolic process in cells, is tightly regulated at the level of elongation of nascent polypeptide chains.

PI3K/Akt inhibitor LY294002 potentiates homoharringtonine antimyeloma activity in myeloma cells adhered to stromal cells and in SCID mouse xenograft.

Homoharringtonine (HHT) is a known anti-leukemia drug that inhibits multiple myeloma (MM) cells both in vitro and in vivo. Our prior study demonstrated that the potency of HHT in MM cells was compromised significantly when myeloma cells were co-cultured with BM stromal cells. This study aimed to investigate whether PI3K/Akt inhibitor LY294002 could potentiate the antimyeloma activity of HHT against MM cells adhered to BM stromal cells and in vivo xenograft models. A co-culture system composed of MM cells and human stromal cells was employed to mimic MM cells in bone marrow niche. The inhibitory and pro-apoptotic effect of HHT and LY294002 was determined by CCK-8 assay or flow cytometry. Expression of PI3K/Akt signaling molecules and anti-apoptotic protein myeloid cell leukemia-1 (Mcl-1) was assessed by western blot analysis and/or reverse transcription real-time quantitative PCR (RT-qPCR). MM xenografts were used to evaluate antitumor effect of combined therapy with HHT and LY294002. Adhesion to BM stromal cells rendered MM cells resistant to HHT whereas silencing Mcl-1 partly reversed the resistance. LY294002 induced apoptosis in MM cells and potentiated the antimyeloma effects of HHT by inhibiting the PI3K/Akt signal pathway which was abnormally activated during adhesion. LY294002 also enhanced the antimyeloma effect of HHT in in vivo xenograft models. These findings suggest that activation of PI3K/Akt signal pathway was responsible for the resistance to HHT in MM cells adhered to stromal cells. LY294002 can potentiate the antimyeloma activity of HHT both in vitro and in vivo, which may represent a new clinical treatment in MM.

Storage and transport of reconstituted omacetaxine mepesuccinate: Considerations for home administration.

Purpose Omacetaxine mepesuccinate ("omacetaxine") is approved by the US Food and Drug Administration for the treatment of adult patients with chronic- or accelerated-phase chronic myeloid leukemia with resistance and/or intolerance to two or more tyrosine kinase inhibitors. In May 2014, the US Food and Drug Administration approved revisions to the packaging information that included directions for home administration of reconstituted omacetaxine by patients or caregivers using syringes filled at a healthcare facility. We developed recommendations for the transport, storage, and spill-clean procedure of reconstituted omacetaxine for home and clinic administration. Methods We conducted chemical stability and microbial growth studies of reconstituted omacetaxine solution stored in vials and syringes at room temperature or refrigerated for various durations. Several shipping configurations were tested in simulated transport conditions to evaluate their ability to contain solution leakage and maintain product quality during distribution. In addition, we evaluated cleaning products and procedures for their effectiveness in removing residual omacetaxine from household surfaces after mock spills. Results Reconstituted omacetaxine showed limited degradation when refrigerated for 14 days in vials and syringes, and no microbial growth was observed for 12 days after intentional inoculation. In shipping studies, the configurations maintained prepared syringes within the recommended storage temperature range throughout transport and could contain leaks if spills occurred. In the event of an accidental spill in a home environment, effective cleaning can be achieved using household cleaning products and defined procedures. Conclusion These data provide important information regarding the safe transportation and administration of reconstituted omacetaxine in the home and clinic.

HAG (Homoharringtonine, Cytarabine, G-CSF) Regimen for the Treatment of Acute Myeloid Leukemia and Myelodysplastic Syndrome: A Meta-Analysis with 2,314 Participants.

BACKGROUND: In China, the combination of homoharringtonine, cytarabine, and G-CSF (HAG) has been extensively applied for treatment of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). METHODS: We performed a meta-analysis of 2,314 patients (AML, n = 1754; MDS, n = 560) to determine the overall safety and efficacy of this regimen. RESULTS: The complete response (CR) rate of AML patients (53%) was significantly higher than that of MDS/transformed-AML patients (45%; P = 0.007). The CR rate of patients with newly diagnosed AML (62%) was significantly higher than in patients with relapsed/refractory AML (50%; P = 0.001). There were no significant difference in CR rates between elderly AML patients (54%) and all AML patients (P = 0.721). When compared with non-HAG regimens for AML/MDS induction therapy, the CR rate of patients treated with HAG was significantly higher than in treated with intensive chemotherapy (P = 0.000). No significant differences in CR rates were observed between patients treated with HAG and those treated with CAG (cytarabine, aclarubicin, G-CSF) regimens (P = 0.073). HAG regimen was well tolerated, with early death (ED) in 2%, grade IV myelosurrpression in 52% and infection in 50%. Reports of ED and rates of myelosuppression were reduced as compared with intensive chemotherapy (P = 0.000 and P = 0.000, respectively). CONCLUSION: The HAG regimen is an effective and safe regimen for the treatment of AML and MDS, and appears to be more effective and better tolerated than intensive chemotherapy. Future randomized controlled trials and further meta-analyses are strongly needed to confirm its efficacy and safety, especially in comparison with intensive chemotherapy.

Effect of granulocyte colony-stimulating factor priming combined with low-dose cytarabine and homoharringtonine in higher risk myelodysplastic syndrome patients.

As sensitization of leukemia cells with granulocyte colony-stimulating factor (G-CSF) can enhance the cytotoxicity of chemotherapy in myeloid malignancies, a pilot study was conducted in order to evaluate the effect of G-CSF priming combined with low-dose chemotherapy in patients with higher risk myelodysplastic syndrome (MDS). The regimen, G-HA, consisted of cytarabine (Ara-C) 7.5mg/m(2)/12h by subcutaneous injection, days 1-14, homoharringtonine (HHT) 1.5mg/m(2)/day by intravenous continuous infusion, days 1-14, and G-CSF 150mg/m(2)/day by subcutaneous injection, days 0-14. 56 patients were enrolled, 34 patients (61%, 95% confidence interval: 51.44-70.56%) achieved complete remission (CR). Median duration of neutropenia was 7days (ranging from 2 to 16days). Grade 1-2 nonhematologic toxicities were documented, including nausea and vomiting (5%), liver function abnormality (5%), and heart function abnormality (2%). No central nervous system toxicity was found. Mortality within the first 4 weeks was 4%. The G-HA regimen is effective in remission induction for higher risk MDS patients and well tolerated due to the acceptable toxicity in maintenance therapy in the patients who cannot undergo Hematopoietic cell transplantation (HCT).

Effects of the combination of decitabine and homoharringtonine in SKM-1 and Kg-1a cells.

The methylation inhibitor decitabine (DAC) has great therapeutic value for myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). However, DAC monotherapy is associated with relatively low rates of overall response and complete remission. Previous studies have shown promising results for combination treatment regimens including DAC. Homoharringtonine (HHT), an alkaloid from Chinese natural plants and Cephalotaxus, has demonstrated potential for leukemia treatment. Our studies have suggested that the combination of DAC and HHT has synergistic effects for inhibiting the viability of SKM-1 and Kg-1a cells. This combination leads to enhanced inhibition of colony formation and apoptosis induction compared with DAC alone in SKM-1 but not Kg-1a cells. Only high-dose DAC and HHT significantly up-regulate caspase-3 and caspase-9 and inhibit BCL-XL in the SKM-1 cell line. The combined effects of DAC plus HHT on apoptosis may not only depend on regulation of the apoptosis-related genes we examined but others as well. HHT had no demethylation effects, and HHT in combination with DAC had no enhanced effects on hypomethylation and DNMT1, DNMT3A and DNMT3B mRNA expression in SKM-1 cells. Overall, these results suggest that DAC used in combination with HHT may have clinical potential for MDS treatment.

Homoharringtonine, aclarubicin and cytarabine (HAA) regimen as the first course of induction therapy is highly effective for acute myeloid leukemia with t (8;21).

Homoharringtonine combined aclarubicin and cytarabine (HAA) has been demonstrated to achieve a high remission rate and provide a survival advantage in acute myeloid leukemia (AML). To investigate whether HAA is an ideal induction regimen for t(8;21)AML, we retrospectively analyzed the data of 140 patients from the last 8 years in our center. When achieving complete remission (CR), the post-remission treatment was administered as a minimal residual disease-directed risk-stratification treatment protocol. The RUNX1/RUNX1T1 transcript level was assessed by RT-qPCR. The last follow-up was conducted in October 2015. In total, thirty patients received an HAA regimen as the induction treatment. The CR rate after one cycle of the HAA regimen was 93.3% (28/30). One patient achieved partial remission, and one had no response. No patients died during induction treatment. The median fold decrease of the RUNX1/RUNX1T1 transcript level was 200 (1-358000), and 16.7% (5/30) patients achieved >3 log decrease after one cycle of the HAA regimen. The estimated 4-year disease-free survival and overall survival were 89.9% and 90.8%, respectively. We concluded that the HAA regimen is highly effective as the first course of induction therapy for t(8;21) AML, and this needs to be confirmed in a large population in the future.

Efficacy and toxicity of decitabine versus CHG regimen (low-dose cytarabine, homoharringtonine and granulocyte colony-stimulating factor) in patients with higher risk myelodysplastic syndrome: a retrospective study.

Decitabine and CHG regimen (low-dose cytarabine and homoharringtonine with G-CSF) have been used for treating higher risk myelodysplastic syndrome (MDS). In this study, we retrospectively compared the efficacy and toxicity of the two regimens in 132 MDS patients. Complete remission (CR) was not significantly different between the groups (27.1% with decitabine vs. 30.6% with CHG, p = 0.657). The CR rate with decitabine (58.8%) was significantly higher than that with CHG (7.7%) (p = 0.007) among the patients with poor karyotypes. Five of 23 (21.7%) patients who failed to respond to decitabine achieved CR with CHG, while one of two patients achieved CR with decitabine after failure with CHG. Overall and relapse-free survival were not different between the groups. In conclusion, both decitabine and CHG regimen are effective for higher risk MDS; there is no cross resistance between the regimens. Decitabine might be a better choice for patients with poor karyotypes.

Targeting of BCL2 Family Proteins with ABT-199 and Homoharringtonine Reveals BCL2- and MCL1-Dependent Subgroups of Diffuse Large B-Cell Lymphoma.

PURPOSE: To investigate the roles of BCL2, MCL1, and BCL-XL in the survival of diffuse large B-cell lymphoma (DLBCL). EXPERIMENTAL DESIGNS: Immunohistochemical analysis of 105 primary DLBCL samples, and Western blot analysis of 18 DLBCL cell lines for the expression of BCL2, MCL1, and BCL-XL. Pharmacologic targeting of BCL2, MCL1, and BCL-XL with ABT-199, homoharringtonine (HHT), and ABT-737. Analysis of DLBCL clones with manipulated expressions of BCL2, MCL1, and BCL-XL. Immunoprecipitation of MCL1 complexes in selected DLBCL cell lines. Experimental therapy aimed at inhibition of BCL2 and MCL1 using ABT-199 and HHT, single agent, or in combination, in vitro and in vivo on primary cell-based murine xenograft models of DLBCL. RESULTS: By the pharmacologic targeting of BCL2, MCL1, and BCL-XL, we demonstrated that DLBCL can be divided into BCL2-dependent and MCL1-dependent subgroups with a less pronounced role left for BCL-XL. Derived DLBCL clones with manipulated expressions of BCL2, MCL1, and BCL-XL, as well as the immunoprecipitation experiments, which analyzed MCL1 protein complexes, confirmed these findings at the molecular level. We demonstrated that concurrent inhibition of BCL2 and MCL1 with ABT-199 and HHT induced significant synthetic lethality in most BCL2-expressing DLBCL cell lines. The marked cytotoxic synergy between ABT-199 and HHT was also confirmed in vivo using primary cell-based murine xenograft models of DLBCL. CONCLUSIONS: As homoharringtonine is a clinically approved antileukemia drug, and ABT-199 is in advanced phases of diverse clinical trials, our data might have direct implications for novel concepts of early clinical trials in patients with aggressive DLBCL.

The hypomethylating agent decitabine prior to chemotherapy improves the therapy efficacy in refractory/relapsed acute myeloid leukemia patients.

In this study, we investigated the effect of pre-treatment with demethylating agent decitabine on susceptibility to chemotherapeutic drugs in HL60/ADR, Kasumi-1 and primary AML cells. Cytotoxic effect was increased by decitabine through activation of p53 and inhibition of c-Myc, Survivin and Bcl-2. We demonstrated in clinic that combination of decitabine and HAA consisting of harringtonine, aclarubicin and cytarabine was effective and safe to treat patients with refractory, relapsed or high-risk AML. Decitabine prior to HAA regimen improved the first induction complete response rate, and significantly prolonged overall survival and disease-free survival in these patients compared with HAA alone. These findings support clinic protocols based on decitabine prior to chemotherapy to overcome resistance and improve therapeutic efficacy in AML patients.

Final analysis of the efficacy and safety of omacetaxine mepesuccinate in patients with chronic- or accelerated-phase chronic myeloid leukemia: Results with 24 months of follow-up.

BACKGROUND: Omacetaxine, a protein synthesis inhibitor, is indicated in the United States for the treatment of patients with chronic-phase (CP) or accelerated-phase (AP) chronic myeloid leukemia (CML) with resistance and/or intolerance to 2 or more tyrosine kinase inhibitors. METHODS: The final analysis, with 24 months of follow-up, included additional efficacy and safety analyses to assess the benefit of long-term omacetaxine administration (1.25 mg/m(2) twice daily for 14 days every 28 days followed by 7 days every 28 days) in CP-CML and AP-CML patients receiving >3 cycles. RESULTS: Eighteen percent of CP-CML patients achieved a major cytogenetic response (MCyR) with a median duration of 12.5 months (95% confidence interval [CI], 3.5 months to not reached [NR]); responses were maintained for ≥12 months in 3 of 14 responders, and the median overall survival (OS) was 40.3 months (95% CI, 23.8 months to NR). Among patients with AP-CML, 14% achieved or maintained a major hematologic response for a median of 4.7 months (95% CI, 3.6 months to NR); MCyR was not achieved, and the median OS was 14.3 months (95% CI, 6.7-18.7 months). In patients with CP-CML and patients with AP-CML who received >3 cycles of treatment (n = 50 and n = 14, respectively), the median OS was 49.3 months (95% CI, 23.8 months to NR) and 24.6 months (95% CI, 12-37.2 months), respectively. Grade 3 or higher hematologic toxicities were the major side effects (79% and 73% for CP-CML and AP-CML, respectively), with discontinuation due to toxicity in 10% of CP patients and in 5% of AP patients. CONCLUSIONS: These results suggest that the long-term administration of omacetaxine is feasible with dose adjustments to manage toxicities and that omacetaxine provides a durable benefit for some patients.

Low-dose homoharringtonine and cytarabine in combination with granulocyte colony-stimulating factor for elderly patients with de novo acute myeloid leukemia.

The treatment of young patient with acute myeloid leukemia (AML) has improved dramatically during the past several decades. However, management of elderly patients with AML still remains a challenge. A total of 56 elderly patients with de novo AML were treated with homoharringtonine and cytarabine in combination with granulocyte colony-stimulating factor (HCG). The overall response rate was 75% (60.7%% complete response [CR] and 14.3% partial response). Fourteen (25%) of the 56 patients showed no response. A higher CR rate was observed in patients aged < 70 years, with better-risk or intermediate-risk karyotype and with NPM1 mutations. To the date of the last follow-up, the median overall survival (OS) was 12.0±1.7 months. There were significant correlations of OS with age, initial karyotype, performance status and gene mutations (NPM1,FLT-ITD and DNMT3A) at diagnosis. The early death rate was 7.1%. Hematologic toxicity was well tolerated; and severe non-hematologic toxicity was not observed.

Effectiveness of homoharringtonine (omacetaxine mepesuccinate) for treatment of acute myeloid leukemia: a meta-analysis of Chinese studies.

The present meta-analysis provides an overview on the effectiveness of homoharringtonine (HHT) combination regimens to treat acute myeloid leukemia (AML). Because most of these studies were performed in China, Chinese published clinical studies were used for the analysis. A search for studies from 2006 to 2013 of regimens containing HHT for AML treatment was performed using published studies and Chinese databases in Mandarin. The complete response (CR) and overall response (OR) rates were analyzed, and the fixed effects model and random effects model (REM) were calculated. The heterogeneity of the studies was calculated using Q homogeneity statistics. The meta-analysis included 21 studies (n = 1310, n = 229 pediatric, and n = 216 elderly). HHT was given in combination with cytarabine, daunorubicin, idarubicin, aclacinomycin, mitoxantrone, or granulocyte colony-stimulating factor. Heterogeneity was seen in all analyzed pools, but it was most pronounced in retrospective studies. Overall, the REM showed a CR rate of 65.2%. However, in studies in which HHT-containing regimens were compared to regimens without HHT, the CR rates were 69.1% in randomized trials and 62.8% in retrospective studies. Additionally, in studies with exclusively elderly patients, the CR rate was considerably lower than it was for the studies with mixed age populations (47.5% vs. 65.2%). Higher overall CR rates for HHT-containing regimens in AML treatment in the Chinese studies suggest that HHT could be an active agent in the management of AML. Additional clinical trials are warranted to evaluate the efficacy of HHT in AML treatment.

Subcutaneous omacetaxine mepesuccinate in patients with chronic myeloid leukemia in tyrosine kinase inhibitor-resistant patients: review and perspectives.

The treatment of chronic myelogenous leukemia (CML) has been revolutionized by the introduction of tyrosine kinase inhibitors (TKI), however, with the exception of ponatinib, none of the existing licensed agents seem to eradicate the reservoir of Philadelphia positive stem cells, thus sustaining the disease over time, and retaining activity in cells and patients harboring an ABL T315I mutation. Omacetaxine mepesuccinate (OMA), formerly known as homoharringtonine, is a cephalotaxus alkaloid derivative and an inhibitor of protein synthesis without tyrosine kinase activity developed 35 years ago by Chinese investigators in the treatment of leukemia. This compound demonstrates specific activity in CML and has been recently commercialized in the U.S. for the treatment of patients in chronic or accelerated phase CML with resistance and/or intolerance to two or more tyrosine kinase inhibitors or harboring a T315I ABL mutation. CML patients with a T315I mutation experienced poor overall survival rates in the pre-ponatinib era (median for CP CML 24 months). Recent studies demonstrate the activity of OMA even in such a poor prognosis population. We hereby detail the development of OMA as an effective agent in CML in these patients.

Conventional induction and post-remission therapy in APL: have we arrived?

Since the introduction of all-trans-retinoic acid, the use of this molecularly targeted treatment in combination with anthracycline-based chemotherapy has completely changed the prognosis of acute promyelocytic leukemia (APL) turning it into the most curable acute myeloid leukemia. Also, the use of risk-adapted protocols has optimized the drug combination and the most appropriate dose intensity for each subset of patients classified according to both risk of relapse and vulnerability to drug toxicity. Recent developments have included the investigation of the role of arsenic trioxide (ATO) as front-line treatment after its success in relapsed APL, both to minimize or even omit the use of cytotoxic agents and to reinforce the conventional chemotherapy-based approach. In the present chapter we will address the achievements of conventional treatment with ATRA and chemotherapy, as well as the opportunity to cure more patients with modifications of this therapeutic backbone with the addition of ATO in any phase of treatment.

Homoharringtonine combined with cytarabine to treat chronic myelogenous leukemia in myeloid blast crisis and its impact on bone marrow CD34+CD7+ cells.

BACKGROUND: The therapeutic response of chronic myelogenous leukemia in myeloid blast crisis (CML-MBC) is very poor. AIM: To explore the therapeutic effect of homoharringtonine (HHT) combined with cytarabine (HA regimen) on CML-MBC and its influence on bone marrow CD34+CD7+ cells. RESULTS: Thirty-four patients with CML-MBC were treated with the HA regimen and bone marrow CD34+CD7+ cells were assayed prior to and after treatment. Among 33 evaluable patients, the overall hematological response (complete/ partial hematological response and hematological improvement) was 60.1%. Seven patients (21.2%) had a cytogenetic response 12 months after treatment. In the untreated CMLMBC patients, the proportion of bone marrow CD34+CD7+ cells was much higher than in the control group (19.4 ± 7.9 vs. 4.4 ± 1.5%, p < 0.05) and decreased to 14.1 ± 7.1% (p < 0.05) after treatment. Before treatment, the proportion of CD34+CD7+ cells was lower in the patients who had a hematological response to the HA regimen than in the patients who did not respond. CONCLUSION: The HA regimen is an effective treatment for CML-MBC and CD34+CD7+ cells may be one of the valuable clinical parameters to assess treatment effectiveness.