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The mammalian target of rapamycin (mTOR) signalling pathway has emerged as an important therapeutic target for acute myeloid leukaemia (AML). This study assessed the combination of temsirolimus, an mTOR inhibitor, and lower-dose clofarabine as salvage therapy in older patients with AML. Induction consisted of clofarabine 20 mg/m2 on days 15 and temsirolimus 25 mg (flat dose) on days 1, 8 and 15. Patients achieving complete remission with (CR) or without (CRi) full haematological recovery could receive monthly temsirolimus maintenance. In 53 evaluable patients, the overall remission rate (ORR) was 21% (8% CR, 13% CRi). Median disease-free survival was 3.5 months, and median overall survival was 4 months (9.1 months for responders). The most common non-haematological severe adverse events included infection (48%), febrile neutropenia (34%) and transaminitis (11%). The 30-d all-cause induction mortality was 13%. Laboratory data from 25 patients demonstrated that a >50%in vivo inhibition of S6 ribosomal protein phosphorylation was highly correlated with response rate (75% with inhibition versus 0% without inhibition; P = 0.0001), suggesting that targeting the mTOR pathway is clinically relevant. The acceptable safety profile and the predictive value of target inhibition encourage further investigation of this novel regimen.

Angiogenesis is mainly regulated by the vascular endothelial growth factor (VEGF), a mitogen specific for endothelial cells, which binds two tyrosine kinase receptors, VEGFR1 and VEGFR2, on the surface of endothelial cells. Molecules targeting VEGF receptors are attractive to pharmacologically treat diseases associated with angiogenesis or to be used as probes in angiogenesis imaging. Recently, we reported a designed peptide targeting VEGF receptors and able to inhibit the VEGF-angiogenic response in vitro and in vivo. In this study, we employed NMR and molecular modeling methodology to investigate the molecular determinants of the interaction peptide-receptor. In particular, the peptide binding site on VEGFR1 domain 2 and the residues involved in receptor recognition have been determined. These results provide significant information to develop a new class of molecules able to recognize the VEGF receptors overexpressed in pathological angiogenesis. © 2013 European Peptide Society and John Wiley & Sons, Ltd.

VEGF receptors have been the target of intense research aimed to develop molecules able to inhibit or stimulate angiogenesis. Based on the x-ray structure of the complex placental growth factor-VEGF receptor 1D2, we designed a VEGF receptor-binding peptide reproducing the placental growth factor β-hairpin region Gln87-Val100 that is involved in receptor recognition. A conformational analysis showed that the designed peptide adopts the expected fold in pure water. Moreover, a combination of NMR interaction analysis and cell binding studies were used to demonstrate that the peptide targets VEGF receptors. The VEGF receptor 1D2-interacting residues were characterized at the molecular level, and they correspond to the residues recognizing the placental growth factor sequence Gln 87-Val100. Finally, the peptide biological activity was characterized in vitro and in vivo, and it showed a VEGF-like behavior. Indeed, the peptide activated VEGF-dependent intracellular pathways, induced endothelial cell proliferation and rescue from apoptosis, and promoted angiogenesis in vivo. This compound is one of the few peptides known with proangiogenic activity, which makes it a candidate for the development of a novel peptide-based drug for medical applications in therapeutic angiogenesis. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc.

Angiogenesis is crucial to all types of wound healing, including gastric ulcer healing. The most potent promoter of angiogenesis is vascular endothelial growth factor (VEGF). We hypothesized that a 15-amino acid peptide designed to mimic the angiogenic action of VEGF would accelerate gastric ulcer healing. Gastric ulcers were induced in mice by serosal application of acetic acid. Treatment with the VEGF mimetic accelerated gastric ulcer healing when administered orally or intraperitoneally, at a dose of 50 ng/kg or greater. Such healing was not observed when the reverse sequence pentadecapeptide or the full-length VEGF protein was administered. Contrary to our hypothesis, the VEGF mimetic did not significantly increase angiogenesis in the ulcerated stomach. The enhancement of ulcer healing by the VEGF mimetic occurred independently of cyclooxygenase-2 (COX-2) activity but was blocked by inhibitors of inducible nitric oxide synthase (iNOS). These results demonstrate that a VEGF mimetic is a potent stimulus for gastric ulcer healing, even when given orally. The effects of the mimetic were independent of stimulatory effects on angiogenesis and COX-2 activity but were dependent on iNOS-derived NO production.

Clinical and biological features were assessed in 204 consecutive de novo adult acute myeloid leukemia (AML) patients who received intensive chemotherapy regimens. Multiparameter flow cytometric assays both of the multidrug resistance (MDR-1)-associated P-glycoprotein (PGP) using the UIC2 monoclonal antibody (MoAb), and of terminal transferase (TdT) were performed. Cytogenetic findings were obtained from 196 patients with high resolution banding. At onset, UIC2 and TdT positivities were detected in 58.5% and 24% of cases, respectively. There were strict correlations either between UIC2 negativity and FAB M3 or between TdT and FAB M0-M1 (P = 0.001 and0.0001, respectively). On the other hand, age was significantly associated with cytogenetic risk classes (P0.0001). CD34 positivity was highly correlated with TdT expression (P0.0001). Moreover, CD7 and CD11b were significantly represented in UIC2+ subset (P0.0001). Rhodamine 123 (Rh 123) efflux was significantly higher in 75 UIC2 positive patients compared to 65 UIC2 negative ones (P0.001). As regards to cytogenetics, TdT positivity was strongly related either to t(9;22) or single/associated anomalies of chromosome 7; on the other hand, most or all cases with t(8;21) or t(15;17) were UIC2 or TdT negative, respectively. The rate of first complete remission (CR) differed both between UIC2+ and UIC2- cases and between TdT+ and TdT- ones (40% versus 72%, P0.001; and 36% versus 61%, P = 0.001, respectively). The survival rates (Kaplan-Meier method) were significantly shorter either in UIC2+ or in TdT+ patients (P = 0.005 and = 0.011, respectively). UIC2 and TdT negative cases showed longer remission duration (P = 0.03 and = 0.22, respectively). The additional effect of UIC2 and TdT on prognosis allowed us to identify two subsets of patients, the first [UIC2- TdT-] at better and the second [UIC2+ TdT+] at worse clinical outcome compared to single UIC2 and TdT cases, concerning CR (P0.001), survival (P0.0001) and CR duration (P = 0.007). The combinations [UIC2+ TdT-] and [UIC2- TdT+] showed an intermediate clinical course. A strong difference was found between poor risk and intermediate/favorable risk cytogenetic classes with regard to CR rate (P0.0001), overall survival and CR duration (P0.001). Nevertheless, within the poor risk class, UIC2 positivity was able to identify patients at worst prognosis with regard to CR (P = 0.005), survival (P = 0.02) and CR duration (P = 0.015). On the other hand, UIC2 and TdT negativity allowed us to distinguish patients with longer survival (P = 0.012 and = 0.04, respectively) and CR duration (P = 0.04 and = 0.025, respectively) within the intermediate/favorable risk class. The independent prognostic value of UIC2, TdT and cytogenetic risk classes was confirmed in multivariate analysis. These results suggest that PGP and TdT expressions, together with cytogenetic findings, may represent a basic predictor of chemotherapeutic failure in AML.

Apolipoprotein A-I (ApoA-I) is the main protein component of the high density lipoproteins and it plays an important role in the reverse cholesterol transport. In particular, it stimulates cholesterol efflux from peripheral cells toward liver and activates the enzyme lecithin-cholesterol acyltransferase (LCAT). Haptoglobin (Hpt), a plasma ?(2) -glycoprotein belonging to the family of acute-phase proteins, binds to ApoA-I inhibiting the stimulation of the enzyme LCAT. Previously, we reported that a synthetic peptide, P2a, binds to and displaces Hpt from ApoA-I restoring the LCAT cholesterol esterification activity in the presence of Hpt. Here, we investigate the molecular determinants underlining the interaction between Hpt and P2a peptide. Analysis of truncated P2a analogs showed that P2a sequence can only be slight reduced in length at the N-terminal to preserve the ability of binding to Hpt. Binding assays showed that charged residues are not involved in Hpt recognition; actually, E146A and D157A substitutions increase the binding affinity to Hpt. Biological characterization of the corresponding P2a peptide analogs, Apo146 and Apo157, showed that the two peptides interfere with Hpt binding to HDL and are more effective than P2a peptide in rescue LCAT activity from Hpt inhibition. This result suggests novel hints to design peptides with anti-atherogenic activity.

VEGF receptors have been the target of intense research aimed to develop molecules able to inhibit or stimulate angiogenesis. Based on the x-ray structure of the complex placental growth factor-VEGF receptor 1,2, we designed a VEGF receptor-binding peptide reproducing the placental growth factor beta-hairpin region Gln(87)-Val(100) that is involved in receptor recognition. A conformational analysis showed that the designed peptide adopts the expected fold in pure water. Moreover, a combination of NMR interaction analysis and cell binding studies were used to demonstrate that the peptide targets VEGF receptors. The VEGF receptor 1(D2)-interacting residues were characterized at the molecular level, and they correspond to the residues recognizing the placental growth factor sequence Gln(87)-Val(100). Finally, the peptide biological activity was characterized in vitro and in vivo, and it showed a VEGF-like behavior. Indeed, the peptide activated VEGF-dependent intracellular pathways, induced endothelial cell proliferation and rescue from apoptosis, and promoted angiogenesis in vivo. This compound is one of the few peptides known with proangiogenic activity, which makes it a candidate for the development of a novel peptide-based drug for medical applications in therapeutic angiogenesis.

Because of its B-cell depleting effect, rituximab has entered clinical trials in several autoimmune conditions. This study assesses the efficacy and safety of rituximab in 57 adults with chronic immune thrombocytopenic purpura (ITP). All patients had platelet counts30 x 10(9)/l, all had received two or more previous ITP treatments and 31 had undergone splenectomy. Patients received rituximab 375 mg/m(2) weekly for 4 weeks. Thirty-one patients (54%) responded, achieving a platelet count50 x 10(9)/l: 18 achieved a complete response (CR: platelet count150 x 10(9)/l) and 13 a partial response (PR: platelet count 50-150 x 10(9)/l). Twenty-nine responses occurred within 8 weeks of the first infusion. Sixteen of 18 CR patients (28% overall), including eight who had failed splenectomy, continued in CR after a median of 72.5 weeks; 15 of 16 are1 year from the first infusion. Only two of 13 maintained a PR. Thirty-three patients experienced grade 1-2 adverse events and one a grade 3 event, but they all completed treatment. Circulating B cells fell to0.03 x 10(9)/l. No changes in immunoglobulin levels or infectious complications were seen. In summary, rituximab was well tolerated with no immediate complications and induced a lasting, substantial response in 32% of adults with chronic ITP.

The outcome of a cohort of 218 consecutive patients who failed to respond to a single course of standard daunorubicin plus ARAC (three + seven) induction regimen has been retrospectively evaluated to assess the characteristics of this group of AML patients and the effectiveness of second-line induction programs. Seventy-four of the 218 patients (33.9%) attained complete remission with salvage chemotherapies. The multivariate analysis of pretherapy characteristics of the patients showed that peroxidase positivity and age were the most important factors in determining whether or not the patient would have a favorable response to second-line induction regimen. In addition, comparison of marrow characteristics at diagnosis with those of marrow after the first-line therapy (marrow leukemic index, MLI) provided the greatest differences between second-line CR and resistant patients. Finally, peroxidase positivity and MLI predicted for remission duration and overall survival. Allogeneic BMT, however, appeared the most important factor for survival and event-free survival of remitting patients. These results are of importance when considering that better defined prognostic factors provide an objective rationale for selecting appropriate strategies for the treatment of patients who do not respond to a single course of induction regimen.

Although morphology and cytochemistry continue to be the mainstay of the diagnosis of acute leukemia (AL), new developments in immunophenotyping, cytogenetics, molecular biology, and in vitro assays have dramatically improved our understanding of this disease and enabled the identification of entities with distinct clinico-biologic features. Immunophenotyping is essential for diagnosing and subclassifying acute lymphoblastic leukemia (ALL) and is also very helpful in certain types of acute myeloid leukemias (AML), such as AML with minimal differentiation or acute megakaryoblastic leukemia. Cytogenetic findings are clinically relevant for diagnosis and prognosis. Nonrandom chromosomal abnormalities such as t(15;17)(q22;q12) or t(1;19)(q23;p13) have been so closely associated with distinct types of acute leukemias that their recognition can allow diagnosis independent of the other criteria. Molecular analysis is a powerful method in the assessment of the malignant potential, clonality, and classification of the ALs. It has become clear that in some leukemias a proportion of patients exhibit the biologically relevant molecular defect in the absence of a karyotypic equivalent. On the other hand apparently uniform chromosomal abnormalities such as the t(1;19), t(9;22), t(8;14), or t(15;17) may differ at the molecular level. In vitro assays can evaluate the growth pattern and cell-cycle kinetics of leukemic cells, as well as their sensitivity to therapeutic agents. All these data are relevant to the management of AL. Because the French-American-British (FAB) classification does not fully correlate with much of this new information, alternative classifications have been proposed. In this review we concentrate on recent diagnostic contributions resulting from advances in biotechnology and discuss some of the points that arouse controversy in the single classifications.

This study assesses the value of immunologic and ultrastructural methods in disclosing the lineage commitment of cells from acute leukemias (ALs). Two hundred and fifty-one ALs were characterized morphologically, cytochemically, and immunologically. Myeloperoxidase (MPO) positivity in3% of blasts was regarded as evidence of the myeloid origin of leukemic cells, cytoplasmic CD22 (cCD22) expression was taken as an indication for B-lineage acute lymphoblastic leukemia (ALL), and CD3+ (membrane or cytoplasmic) cases were classified as T-ALL. Diagnosis of minimally differentiated acute myeloid leukemia (AML-M0) was made when blast cells had undifferentiated features by light microscopy, reacted with at least one of the antibodies to myeloid-specific antigens (CD13, CD33, MPO), and lacked CD19, cCD22, and c/mCD3. Megakaryoblastic differentiation was demonstrated by the expression of CD41 and/or CD61. Following these criteria, 209 cases were classified as acute myeloid leukemia (AML) and 39 as ALL. Expression of lymphoid antigens was detected in 45% of AML cases and 30% of ALLs showed myeloid antigens. One case was regarded as a true biphenotypic leukemia because of the combined expression of MPO and CD33 for the myeloid lineage, and cCD3, CD2, and CD5 for the T-cell lineage. Two cases lacked signs of myeloid or lymphoid differentiation and were studied by electron microscopy methods. One displayed platelet peroxidase (PPO) activity and was classified as a megakaryoblastic variant, one other reacted with anti-CD33 and was considered AML-M0. We conclude that light microscopy and standard immunologic methods can accurately demonstrate the lineage orientation in greater than 99% of ALs. Integration with ultrastructural analysis can define the cell nature of virtually all cases of AL.