Search

Primary central nervous system lymphomas (PCNSLs) classically remain confined within the CNS throughout their evolution for unknown reasons. Our objective was to analyse the rare extracerebral relapses of PCNSL in a nationwide population-based study. We retrospectively selected PCNSL patients who experienced extracerebral relapse during their follow-up from the French LOC database. Of the 1968 PCNSL included in the database from 2011, 30 (1.5%, median age 71 years, median KPS 70) presented an extracerebral relapse, either pure (n = 20) or mixed (both extracerebral and in the CNS) (n = 10), with a histological confirmation in 20 cases. The median delay between initial diagnosis and systemic relapse was 15.5 months [2-121 months]. We found visceral (n = 23, 77%), including testis in 5 (28%) men and breast in 3 (27%) women, lymph node (n = 12, 40%), and peripheral nervous system (PNS) (n = 7, 23%) involvement. Twenty-seven patients were treated with chemotherapy, either with only systemic targets (n = 7) or mixed systemic and CNS targets (n = 20), 4 were consolidated by HCT-ASCT. After systemic relapse, the median progression-free survival and overall survival (OS) were 7 and 12 months, respectively. KPS > 70 and pure systemic relapses were significantly associated with higher OS. Extracerebral PCNSL relapses are rare, mainly extranodal, and frequently involve the testis, breast, and PNS. The prognosis was worse in mixed relapses. Early relapses raise the question of misdiagnosed occult extracerebral lymphoma at diagnostic workup that should systematically include a PET-CT. Paired tumour analysis at diagnosis/relapse would provide a better understanding of the underlying molecular mechanisms. [ABSTRACT FROM AUTHOR]

In conjunction with two phase I clinical trials, we have investigated the pharmacokinetics of marcellomycin (MCM), a new class II anthracycline antibiotic, in nine patients with normal renal and hepatic functions and no third-space fluid accumulation. MCM was infused IV over 15 min at a dosage of 27.5, 40, or 50 mg/m2. Plasma and urine samples were collected up to 72 h. MCM and metabolites were assayed by thin-layer chromatography and quantified by specific fluorescence. The disappearance of total MCM-derived fluorescence from plasma followed first-order kinetics and lacked the rebound in total fluorescence that has been described for the structurally similar agent, aclacinomycin A. After 40-50 mg/m2, the peak MCM concentration in plasma was 1.67 +/- 0.61 microM; MCM disappeared from plasma in a triexponential fashion and was undetectable by 48 h after infusion. The area under the plasma concentration-time plot (AUC), including the infusion time, was 1.11 +/- 0.39 microM X h; plasma clearance of MCM was 1.50 +/- 0.88 l/min/m2. Five other fluorescent compounds were consistently observed in plasma. M2 was a contaminant present in the parent drug. P1 and P2 were conjugates of MCM and M2, respectively. G1 and G2 were aglycones. The peak concentrations of the metabolites were 25% or less or the peak concentration for MCM, but their persistence resulted in higher AUCs than that for MCM. For the dosage of 27.5 mg/m2, fewer data were available; but the pharmacokinetics of MCM and metabolites appeared to be similar to that at higher dosage. Urinary excretion of total fluorescence amounted to 8.0% +/- 1.6% of the total dose at 40-50 mg/m2, and to 7.0% +/- 2.3% at 27.5 mg/m2. No correlation was detected among the various pharmacokinetic parameters and toxicities encountered in these patients. [ABSTRACT FROM AUTHOR]

Phosphorylation by Akt on Ser 280 was reported to induce cytoplasmic retention and inactivation of CHK1 with consequent genetic instability in PTEN−/− cells. In acute myeloid leukemia cells carrying the FLT3-internal tandem duplication (ITD) mutation, we observed high rates of FLT3-ITD-dependent CHK1 Ser 280 phosphorylation. Pharmacological inhibition and RNA interference identified Pim1/2, not Akt, as effectors of this phosphorylation. Pim1 catalyzed Ser 280 phosphorylation in vitro and ectopic expression of Pim1/2-induced CHK1 phosphorylation. Ser 280 phosphorylation did not modify CHK1 localization, but facilitated its cell cycle and resistance functions in leukemic cells. FLT3, PIM or CHK1 inhibitors synergized with DNA-damaging agents to induce apoptosis, allowing cells to bypass the etoposide-induced G2/M arrest. Consistently, etoposide-induced CHK1-dependent phosphorylations of CDC25C on Ser 216 and histone H3 on Thr11 were decreased upon FLT3 inhibition. Accordingly, ectopic expression of CHK1 improved the resistance of FLT3-ITD cells and maintained histone H3 phosphorylation in response to DNA damage, whereas expression of unphosphorylated Ser 280Ala mutant did not. Finally, FLT3- and Pim-dependent phosphorylation of CHK1 on Ser 280 was confirmed in primary blasts from patients. These results identify a new pathway involved in the resistance of FLT3-ITD leukemic cells to genotoxic agents, and they constitute the first report of CHK1 Ser 280 regulation in myeloid malignancies. [ABSTRACT FROM AUTHOR]

The mTORC1 signaling pathway is constitutively activated in almost all acute myelogenous leukemia (AML) patients. We conducted a phase Ib trial combining RAD001 (everolimus), an allosteric inhibitor of mTORC1, and conventional chemotherapy, in AML patients under 65 years of age at first relapse (clinical trial NCT 01074086). Increasing doses of RAD001 from 10-70 mg were administrated orally on days 1 and 7 (d1 and d7) of a 3+7 daunorubicin+cytarabine conventional induction chemotherapy regimen. Twenty-eight patients were enrolled in this trial. The treatment was well tolerated with <10% toxicity, mainly involving the gastrointestinal tract and lungs. In this phase Ib trial, the RAD001 maximum tolerated dose was not reached at 70 mg. Sixty-eight percent of patients achieved CR, of which 14 received a double induction. Eight subsequently were intensified with allogeneic-stem cell transplant. Strong plasma inhibition of P-p70S6K was observed after RAD001 administration, still detectable at d7 (d7)at the 70 mg dosage. CR rates in patients with RAD001 areas under or above the curve median were 53% versus 85%. A 70 mg dose of RAD001 at d1 and d7 of an induction chemotherapy regimen for AML has acceptable toxicity and may improve treatment. [ABSTRACT FROM AUTHOR]

Background:Cancer cells are frequently addicted to deregulated oncogenic protein translation. The small molecule 4EG-I selectively inhibits the cap-dependent translation of mRNAs. As multiple myeloma is an incurable disease that requires new therapeutic approaches, we investigated whether targeting the translation initiation pathway could be a target for myeloma therapy.Methods:Six myeloma cell lines and primary samples were included in this study. The 4EGI-1 effect was determined by AnnexinV staining and caspase activation. Modification of Bcl-2 protein expression was analysed, and the significance of modified proteins was analysed by knock-down experiments.Results:We demonstrated that 4EGI-1 impaired the assembly of the eIF4F complex and decreased the expression of the eIF4E-regulated proteins in myeloma cells. Furthermore, we showed that 4EGI-1 induced strong apoptosis in five out of six myeloma cell lines. Apoptosis is associated with the activation of the intrinsic mitochondrial pathway. The 4EGI-1 triggered Noxa induction only in cells undergoing apoptosis through endoplasmic reticulum (ER) stress. Furthermore, Noxa silencing prevented myeloma cells from 4EGI-1-induced apoptosis. Finally, Noxa induction led to a disruption of Mcl-1/Bim complexes in parallel to the generation of 'Mcl-1-free Noxa'.Conclusion:Our results suggested that the use of inhibitors that directly target the translation initiation complex eIF4F could represent a potential novel approach for multiple myeloma therapy. [ABSTRACT FROM AUTHOR]

Mammalian target of rapamycin (mTOR) is a protein kinase implicated in the regulation of various cellular processes, including those required for tumor development, such as the initiation of mRNA translation, cell-cycle progression and cellular proliferation. In a wide range of hematological malignancies, the mTORC1 signaling pathway has been found to be deregulated and has been designed as a major target for tumor therapy. Given that pre-clinical studies have clearly established the therapeutic value of mTORC1 inhibition, numerous clinical trials of rapamycin and its derivates (rapalogs) are ongoing for treatment of these diseases. At this time, although disease stabilization and tumor regression have been observed, objective responses in some tumor types have been modest. Nevertheless, some of the mechanisms underlying cancer-cell resistance to rapamycin have now been described, thereby leading to the development of new strategy to efficiently target mTOR signaling in these diseases. In this review, we discuss the rationale for using mTOR inhibitors as novel therapies for a variety of hematological, malignancies with a focus on promising new perspectives for these approaches. [ABSTRACT FROM AUTHOR]

The phosphatidylinositol 3-kinase (PI3K)/Akt and mammalian target of rapamycin complex 1 (mTORC1) signaling pathways are frequently activated in acute myelogenous leukemia (AML). mTORC1 inhibition with RAD001 induces PI3K/Akt activation and both pathways are activated independently, providing a rationale for dual inhibition of both pathways. PI-103 is a new potent PI3K/Akt and mTOR inhibitor. In human leukemic cell lines and in primary blast cells from AML patients, PI-103 inhibited constitutive and growth factor-induced PI3K/Akt and mTORC1 activation. PI-103 was essentially cytostatic for cell lines and induced cell cycle arrest in the G1 phase. In blast cells, PI-103 inhibited leukemic proliferation, the clonogenicity of leukemic progenitors and induced mitochondrial apoptosis, especially in the compartment containing leukemic stem cells. In contrast, apoptosis was not induced with RAD001 and IC87114 association, which specifically inhibits mTORC1 and p110δ activity, respectively. PI-103 had additive proapoptotic effects with etoposide in blast cells and in immature leukemic cells. Interestingly, PI-103 did not induce apoptosis in normal CD34+ cells and had moderate effects on their clonogenic and proliferative properties. Here, we demonstrate that multitargeted therapy against PI3K/Akt and mTOR with PI-103 may be of therapeutic value in AML.Leukemia (2008) 22, 1698–1706; doi:10.1038/leu.2008.144; published online 12 June 2008 [ABSTRACT FROM AUTHOR]

Fludarabine (FDR) therapy gives a response rate of about 30% in previously treated patients with Waldenström's macroglobulinemia (WM). The combination of FDR and cyclophosphamide (Cy) has been shown to be effective in chronic lymphoproliferative disorders. We administered the combination of FDR (30 mg/m2 i.v. D1–D3) and Cy (300 mg/m2 i.v. D1–D3) to 49 patients. Median age was 64 years. The median hemoglobin, albumin, beta 2 microglobulin and immunoglobulin M (IgM) levels were 9.9 g/100 ml, 39.6 g/l, 3 mg/l and 24.7 g/l, respectively. In all, 14 patients (29%) had not previously been treated. FDR/Cy was administered every 4 weeks for a median of four cycles. In all, 38 patients (77.6%) had partial responses, nine had stable disease and two had progressive disease. After a median of follow-up of 25 months, six patients relapsed and two patients developed large-cell lymphoma. The median time to treatment failure was 27 months. The main toxicity was hematological. In all, 12 patients died, four from progression, one from large-cell lymphoma, three from infection and four from a second malignancy. Two factors negatively influenced overall and event-free survival, age >65 years and IgM <40 g/l. The FDR/Cy combination, therefore, gives a high response rate in WM, even in previously treated patients with factors of poor prognosis.Leukemia (2005) 19, 1831–1834. doi:10.1038/sj.leu.2403885; published online 25 August 2005 [ABSTRACT FROM AUTHOR]

The metabolism and tissue distribution of aclacinomycin A (ACL), marcellomycin (MCM), and musettamycin (MST), three new anthracycline antibiotics, were compared after IV administration to mice. In plasma, total MCM- and ACL-derived fluorescence declined according to first-order kinetics, whereas an initial decline followed by a rebound was observed for MST. In plasma, MCM remained the predominant compound. ACL was eliminated more quickly, and was replaced by two metabolites, the reduced glycoside M1, and an aglycone. In the case of MST, two unidentified metabolites were observed in concentrations equivalent to that of the parent drug. The three drugs were distributed widely to organs, but only ACL achieved measurable concentrations in the brain. Initially, high concentrations of all three drugs were present in the lungs, but these decreased quickly to values similar to those present in the liver and kidneys. Intermediate concentrations of the three drugs were measured in heart and skeletal muscle. Splenic concentrations of all three drugs rose progressively, reaching a maximum at 8 h after injection in the case of ACL and MST, and at 24 h after injection in the case of MCM. Concentrations of the metabolites of MCM and MST were low in all organs except liver and kidney, where the aglycones 7-deoxypyrromycinone and bisanhydropyrromycinone were seen. The metabolism of ACL was extensive. Aglycones were dominant in the liver and kidneys, whereas reduced glycosides predominated in the spleen. These observations indicate that the murine pharmacology of these three structurally similar drugs differs markedly. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented on the influence of Nucleophosmin status in acute myeloid leukemia with normal karyotype.

A letter to the editor is presented in response to the article "Constitutive Phosphoinositide 3-Kinase Activation in Acute Myeloid Leukemia Is Not Due to p110δ Mutations," published in the December 8, 2005 issue.