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Chemotherapy induced polyploidy is a mechanism of inherited drug resistance resulting in an aggressive disease course in cancer patients. Alisertib, an Aurora Kinase A (AK-A) ATP site inhibitor, induces cell cycle disruption resulting in polyaneuploidy in Diffuse Large B Cell Lymphoma (DLBCL). Propidium iodide flow cytometry was utilized to quantify alisertib induced polyploidy in U2932 and VAL cell lines. In U2932 cells, 1µM alisertib generated 8n+ polyploidy in 48% of the total cell population after 5 days of treatment. Combination of Aurkin A an AK-A/TPX2 site inhibitor, plus alisertib disrupted alisertib induced polyploidy in a dose-dependent manner with associated increased apoptosis. We generated a stable FUCCI U2932 cell line expressing Geminin-clover (S/G 2 /M) and cdt1-mKO (G 1 ), to monitor cell cycle progression. Using this system, we identified alisertib induces polyploidy through endomitosis, which was eliminated with Aurkin A treatment. In a VAL mouse xenograft model, we show polyploidy generation in alisertib treated mice versus vehicle control or Aurkin A. Aurkin A plus alisertib significantly reduced polyploidy to vehicle control levels. Our in vitro and in vivo studies show that Aurkin A synergizes with alisertib and significantly decreases the alisertib dose needed to disrupt polyploidy while increasing apoptosis in DLBCL cells., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Cyclophosphamide combined with total body irradiation (Cy/TBI) or busulfan (BuCy) are the most widely used myeloablative conditioning regimens for allotransplants. Recent data regarding their comparative effectiveness are lacking. We analyzed data from the Center for International Blood and Marrow Transplant Research for 1230 subjects receiving a first hematopoietic cell transplant from a human leukocyte antigen-matched sibling or from an unrelated donor during the years 2000 to 2006 for acute myeloid leukemia (AML) in first complete remission (CR) after conditioning with Cy/TBI or oral or intravenous (IV) BuCy. Multivariate analysis showed significantly less nonrelapse mortality (relative risk [RR] = 0.58; 95% confidence interval [CI]: 0.39-0.86; P = .007), and relapse after, but not before, 1 year posttransplant (RR = 0.23; 95% CI: 0.08-0.65; P = .006), and better leukemia-free survival (RR = 0.70; 95% CI: 0.55-0.88; P = .003) and survival (RR = 0.68; 95% CI: 0.52-0.88; P = .003) in persons receiving IV, but not oral, Bu compared with TBI. In combination with Cy, IV Bu is associated with superior outcomes compared with TBI in patients with AML in first CR.

After the transplantation of unmodified marrow from human leukocyte antigen-matched unrelated donors receiving cyclosporine (CSP) and methotrexate (MTX), the incidence of acute graft-versus-host disease (GVHD) is greater than 75%. Tacrolimus is a macrolide compound that, in previous preclinical and clinical studies, was effective in combination with MTX for the prevention of acute GVHD. Between March 1995 and September 1996, 180 patients were randomized in a phase 3, open-label, multicenter study to determine whether tacrolimus combined with a short course of MTX (n = 90), more than CSP and a short course of MTX (n = 90), would reduce the incidence of acute GVHD after marrow transplantation from unrelated donors. There was a significant trend toward decreased severity of acute GVHD across all grades (P =.005). Based on the Kaplan-Meier estimate, the probability of grade II-IV acute GVHD in the tacrolimus group (56%) was significantly lower than in the CSP group (74%; P =.0002). Use of glucocorticoids for the management of GVHD was significantly lower with tacrolimus than with CSP (65% vs 81%, respectively; P =. 019). The number of patients requiring dialysis in the first 100 days was similar (tacrolimus, 9; CSP, 8). Overall and relapse-free survival rates for the tacrolimus and CSP arms at 2 years was 54% versus 50% (P =.46) and 47% versus 42% (P =.58), respectively. The combination of tacrolimus and MTX after unrelated donor marrow transplantation significantly decreased the risk for acute GVHD than did the combination of CSP and MTX, with no significant increase in toxicity, infections, or leukemia relapse.

Patients with severe congenital neutropenia (SCN) are at increased risk for the development of acute myelogenous leukemia (AML). In the subset of patients with SCN that progresses to AML, acquired mutations in the receptor for granulocyte colony-stimulating factor (G-CSF) have been detected that result in the expression of truncated forms of the G-CSF receptor (G-CSFR) protein. G-CSFR truncation mutants from these patients transduce hyperproliferative growth responses. In this paper, we show that the most frequently isolated mutant G-CSFR form from patients with SCN/AML (delta716) confers resistance to apoptosis and prolongs cell survival through a mechanism involving Akt, a downstream target of PI3-kinase. G-CSF stimulation of cells expressing the G-CSFR truncation mutant induces sustained activation of Akt and prolonged phosphorylation of the pro-apoptotic protein Bad, resulting in enhanced cell survival. Extension of cell survival allowing for sufficient time for the acquisition of additional oncogenic events may represent an important mechanism by which G-CSFR mutations contribute to leukemogenesis. These data provide further insight into the pathophysiologic contribution of G-CSFR mutations to AML. (Blood. 2000;95:2132-2137)

Acquired mutations in the granulocyte colony-stimulating factor receptor (G-CSFR) occur in a subset of patients with severe congenital neutropenia (SCN) who develop acute myelogenous leukemia (AML). These mutations affect one allele and result in hyperproliferative responses to G-CSF, presumably through a dominant-negative mechanism. Here we show that a critical domain in the G-CSFR that mediates ligand internalization is deleted in mutant G-CSFR forms from patients with SCN/AML. Deletion of this domain results in impaired ligand internalization, defective receptor downmodulation, and enhanced growth signaling. These results explain the molecular basis for G-CSFR mutations in the pathogenesis of the dominant-negative phenotype and hypersensitivity to G-CSF in SCN/AML.

We report the results of a phase III open-label, randomized, multicenter trial comparing tacrolimus/methotrexate to cyclosporine/methotrexate for graft-versus-host disease (GVHD) prophylaxis after HLA-identical sibling marrow transplantation in patients with hematologic malignancy. The primary objective of this study was to compare the incidence of moderate to severe (grade II-IV) acute GVHD. Secondary objectives were to compare the relapse rate, disease-free survival, overall survival, and the incidence of chronic GVHD. Patients were stratified according to age (<40 v >/=40) and for male recipients of a marrow graft from an alloimmunized female. There was a significantly greater proportion of patients with advanced disease randomized to tacrolimus arm (P = . 02). The incidence of grade II-IV acute GVHD was significantly lower in patients who received tacrolimus than patients in the cyclosporine group (31.9% and 44.4%, respectively; P = .01). The incidence of grade III-IV acute GVHD was similar, 17.1% in cyclosporine group and 13.3% in the tacrolimus group. There was no difference in the incidence of chronic GVHD between the tacrolimus and the cyclosporine group (55.9% and 49.4%, respectively; P = .8). However, there was a significantly higher proportion of patients in the cyclosporine group who had clinical extensive chronic GVHD (P = . 03). The relapse rates of the two groups were similar. The patients in the cyclosporine arm had a significantly better 2-year disease-free survival and overall survival than patients in the tacrolimus arm, 50.4% versus 40.5% (P = .01) and 57.2% versus 46.9% (P = .02), respectively. The significant difference in the overall and disease-free survival was largely the result of the patients with advanced disease, 24.8% with tacrolimus versus 41.7% with cyclosporine (P = .006) and 20.4% with tacrolimus versus 28% with cyclosporine (P = .007), respectively. There was a higher frequency of deaths from regimen-related toxicity in patients with advanced disease who received tacrolimus. There was no difference in the disease-free and overall survival in patients with nonadvanced disease. These results show the superiority of tacrolimus/methotrexate over cyclosporine/methotrexate in the prevention of grade II-IV acute GVHD with no difference in disease-free or overall survival in patients with nonadvanced disease. The survival disadvantage in advanced disease patients receiving tacrolimus warrants further investigation.

The allogeneic mixed lymphocyte reaction (MLR) is a complex in vitro assay of T-cell recognition and responsiveness in which interleukin-2 (IL-2) plays a central role. We have previously demonstrated that c-kit ligand (KL) can enhance IL-2-induced proliferation in a subset of human natural killer cells expressing the c-kit tyrosine kinase receptor. In the present study, we asked whether KL could enhance IL-2-mediated T-cell proliferation in the allogeneic MLR. We demonstrate that the vast majority of activated human T-cell clones express the c-kit mRNA transcript. Binding studies performed on activated T cells with radioiodinated KL were consistent with the expression of a single class of c-kit receptors. The addition of exogenous KL to the MLR led to an increase in tritiated thymidine (3[H]-TdR) incorporation in the absence of other exogenous cytokines, and did so in a dose-dependent fashion. A reproducible increase in 3[H]-TdR incorporation was noted at concentrations of KL, which approximate those normally found in vivo. Antibody blocking of KL binding to c-kit, T-cell depletion and sorting experiments suggest that the action of KL is mediated at least in part by a direct effect on both CD4+ and CD8+ T-cells. KL's enhancement of the MLR also requires the binding of IL-2 to its high-affinity IL-2 receptor. Given the abundance of KL normally found in human serum, these data suggest that this cytokine may have a role during T-cell activation in vivo.

The human granulocyte colony-stimulating factor receptor (hG-CSFR) belongs to the cytokine receptor superfamily. As with other members of this family, the cytoplasmic domain of hG-CSFR lacks intrinsic tyrosine kinase activity. To identify critical regions mediating growth signal transduction by hG-CSFR, deletions or site-directed amino acid substitutions were introduced into the cytoplasmic domain of hG-CSFR, and the mutant cDNAs were transfected into the murine interleukin-3 (IL-3)-dependent Ba/F3 and FDCP cell lines. Truncation of the carboxy-terminal end of the receptor to the membrane-proximal 53 amino acids of the cytoplasmic domain, which retained the conserved Box 1 and Box 2 sequence motifs, decreased the ability of hG-CSFR to transduce G-CSF-mediated growth signals without an associated loss in receptor binding affinity. Substitution of proline by alanine at amino acid positions 639 and 641 within Box 1 completely abolished the G-CSF-mediated growth signal. Rapid induction of tyrosine phosphorylation of several cellular proteins, including a 75-kD protein (p75) identified as c-rel, was an early event associated with transduction of proliferative signals by hG-CSFR in Ba/F3 transfectants. Mutant receptors containing Pro-to-Ala substitutions that inactivated the receptor for mitogenic activity also inactivated the receptor for tyrosine-specific phosphorylation of p75. These results show that the conserved Box 1 sequence motif (amino acids 634 to 641) is critical for mitogenesis and activation of cellular tyrosine kinases by hG-CSFR.

Macrophage inflammatory protein-1 alpha (MIP-1 alpha) and its human homologue GOS19.1/LD78 are members of the C-C chemokine/intercrine family of secreted proteins. They have proinflammatory properties and also inhibit cell cycle progression of hematopoietic stem cells. Characterization of MIP-1 alpha receptor(s) has been confused because of its reported aggregation to inactive forms. Using a defined monomeric form of MIP-1 alpha that is biologically active for stem cell inhibition and induction of oxidative metabolism in polymorphonuclear cells, we report the detection of high- and low-affinity receptor classes on human leukemic CD34+ blast cells, promyelocytic cells, monocytes, peripheral blood neutrophils, and T cells. Both high- and low-affinity classes are expressed simultaneously in promyelocytes and neutrophils. The calculated kd for high-affinity receptors correlates with the concentrations of MIP-1 alpha required to induce a biologic effect on stem cells and neutrophils. Cross-linking studies show that MIP-1 alpha associates with two cell surface proteins with apparent molecular masses of 92 kD and 52 kD. Direct competition binding studies combined with studies on the inhibition of stem cells show that human and murine MIP-1 alpha have different receptor-binding and biologic properties.

A decrease in responsiveness to granulocyte colony-stimulating factor (G-CSF) has been implicated in the pathophysiology of cyclic hematopoiesis. Using the canine model of cyclic neutropenia, we examined the response of neutrophil precursors to G-CSF in vitro and G-CSF receptor expression in neutrophils from grey collie dogs to determine whether the abnormal response observed to G-CSF in vivo in this disorder is present at the level of the progenitor cell and is caused by defective G-CSF receptor expression. Bone marrow mononuclear cells from grey collie dogs required sevenfold higher G-CSF concentrations than normal dog cells to achieve half-maximal colony growth [56 pmol/L v 8 pmol/L). Receptor binding assays with 125I-labeled G-CSF and Scatchard analyses of the equilibrium binding data were consistent with expression of a single class of high-affinity receptors for G-CSF on neutrophils from both normal dogs and grey collies with similar receptor numbers (56 to 446 sites/cell v 78 to 199 sites/cell) and binding affinities (28 to 206 pmol/L v 84 to 195 pmol/L). Chemical cross-linking studies identified a G-CSF binding protein of approximately 120 kD on neutrophils from grey collies, similar in size to that on normal dog neutrophils. No abnormal G-CSF receptor mRNA transcripts were detected in neutrophils from grey collie dogs by Northern blot analysis. Treatment of both normal and grey collie neutrophils with G-CSF rapidly induced tyrosine phosphorylation of an 80-kD protein that behaved like canine c-rel. These results demonstrate that the abnormal responsiveness to G-CSF in canine cyclic hematopoiesis is present in neutrophil precursors and is not associated with demonstrable alterations in the number, binding affinity, or overall size of the G-CSF receptor in neutrophils, or with defective tyrosine phosphorylation of p80. These data suggest that cyclic hematopoiesis is caused by a defect in the G-CSF signal transduction pathway at a point distal to G-CSF receptor binding that does not involve the early biochemical events leading to p80 tyrosine phosphorylation.

One hundred fifteen patients with chronic myelocytic leukemia (CML) were administered busulphan 4 mg/kg for 4 days and cyclophosphamide 60 mg/kg on each of 2 days (BuCy2) followed by allogeneic bone marrow transplantation from histocompatible sibling donors. For 62 patients in chronic phase, 26 in accelerated phase, and 27 in blast transformation, the actuarial survival at 3 years was 58%, 41%, and 25%, respectively. Actuarial probability of relapse was 3%, 12%, and 27%, respectively. Only two patients in chronic phase showed a transient cytogenetic relapse and one of these died from subsequent transplant-related complications, whereas the other remains cytogenetically normal 697 days posttransplant. Patients who were transplanted within 1 year of diagnosis in chronic phase had a survival of 70% compared with 40% when transplanted beyond 1 year from diagnosis. This significant difference in survival was due to transplant-related complications and was correlated with previous exposure to high doses of busulphan. This study indicates that BuCy2 is a useful conditioning regimen for marrow transplantation in patients with CML and results in similar survival statistics and transplant-related mortality as would be expected with conditioning regimens containing total body irradiation. It is possible that relapse after BuCy2 may be lower than expected with regimens containing total body irradiation, but larger analyses are required.

One hundred twenty-seven patients with acute myelocytic leukemia (AML) were given busulfan 4 mg/kg on each of 4 days and cyclophosphamide 60 mg/kg on each of 2 days (BuCy2) followed by allogeneic bone marrow transplantation from an HLA-identical or one antigen disparate sibling. For 71 patients in first complete remission, 23 in second complete remission or initial relapse, and 33 patients with primary refractory disease, second or subsequent relapse, or a preceding hematologic disorder, the 3-year leukemia-free survival (LFS) is 63.1%, 32.6%, and 24.2% respectively. The actuarial probability of relapse for each group is 14.1%, 40.6%, and 61.0%. In multivariate analyses, relapse and decreased LFS were associated with advanced disease phase and with M4/M5 French-American-British classification. The LFS of first remission patients was adversely associated with a short time interval from diagnosis to transplantation. This study indicates that BuCy2 is an attractive preparative regimen for marrow transplantation in patients with AML and that prognostic factors for relapse and LFS are similar those described for regimens containing total body irradiation.

Human granulocyte colony-stimulating factor (G-CSF) is a regulatory glycoprotein that stimulates the production of neutrophilic granulocytes from committed hematopoietic progenitor cells both in vitro and in vivo. In this report, we show that biosynthetic (recombinant) human G-CSF enhances colony formation by normal human bone marrow and the human myeloid leukemic cell lines, HL-60 and KG-1, as well as nonhematopoietic small cell lung cancer lines, H128 and H69. G-CSF also modulates multiple differentiated functions of human neutrophils, including enhanced oxidative metabolism in response to f-Met-Leu-Phe (f-MLP), increased antibody-dependent cell-mediated cytotoxicity (ADCC), and augmented arachidonic acid release in response to ionophore and chemotactic agents. These effects are all maximal at a concentration of 100 to 500 pmol/L. Using 125I-labeled recombinant human G-CSF, high affinity binding sites were identified on human neutrophils, the myeloid leukemia cell lines KG-1 and HL-60, and the small cell carcinoma cell lines, H128 and H69. G-CSF receptor numbers ranged between 138 and 285 sites per cell with a kd of 77 to 140 pmol/L, consistent with the concentrations of G-CSF that elicit biologic responses in vitro. Decreased specific binding of 125l-G-CSF by human neutrophils was consistently observed in the presence of excess unlabeled human granulocyte-macrophage colony-stimulating factor (GM-CSF), suggesting competition or down modulation by GM-CSF of the G-CSF receptor.

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates the colony growth of myeloid progenitors in semisolid media, and enhances the function of mature effector cells, including neutrophils, monocytes, and eosinophils. Small cell carcinoma lines (SCCL) have properties of amine precursor uptake and decarboxylation (APUD) cells and express high levels of the enzyme, L-aromatic amino acid decarboxylase. We looked for possible expression of GM-CSF receptors on nonhematopoietic cells and found specific high-affinity binding of human GM-CSF to SCCL and to the SV40-transformed African green monkey kidney cell line, COS. The small cell carcinoma lines responded to GM-CSF with enhanced proliferation, and both small cells and COS cells were found to express authentic 84,000 dalton GM-CSF receptor protein. These findings indicate that nonhematopoietic cells can bind and respond to GM-CSF, suggesting additional biological activities as well as the possibility of tumor responses when GM-CSF is used therapeutically in humans. Since preliminary clinical trials using CSFs as adjunctive treatment in patients with solid tumors are underway, it will be important to consider the possible responsiveness of nonhematopoietic tumor cells to CSFs.

Human erythroid-potentiating activity (EPA) is a 28,000 mol wt glycoprotein that stimulates the growth of erythroid progenitors in vitro and enhances colony formation by the K562 human erythroleukemia cell line. EPA has potent protease inhibitory activity, and is also referred to as tissue inhibitor of metalloproteinases (TIMP). We observed that colony formation by K562 cells in semi-solid medium containing reduced fetal calf serum (FCS) is not directly proportional to the number of cells plated, suggesting production of autostimulatory factors by K562 cells. Using radioimmunoprecipitation and a bioassay for EPA, medium conditioned by K562 cells was found to contain high levels of biologically active EPA; Northern hybridization analysis confirmed the expression of EPA mRNA. Radiolabeled EPA was used to identify cell surface receptors on K562 cells. Together, these results suggest that EPA may act as an autocrine growth factor for K562 cells.