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Biomedical subjects

Edward D Ball

Publications and source records attributed to Edward D Ball.

13 recordsLinked to original sources
PubMed2006

Targeting gastrin-releasing peptide receptors on small cell lung cancer cells with a bispecific molecule that activates polyclonal T lymphocytes.

PURPOSE: Gastrin-releasing peptide (GRP) is a growth factor for small cell lung cancer (SCLC). GRP belongs to the bombesin peptide family and has significant homology to bombesin. We constructed a bispecific molecule, OKT3xAntag2, by conjugating a monoclonal antibody OKT3 (anti-CD3) with a bombesin/GRP antagonist (Antag2) and evaluated cytotoxicity against SCLC cells. EXPERIMENTAL DESIGN: We tested binding of the bispecific molecule to SCLC cell lines and T cells by flow cytometry, antibody-dependent cellular cytotoxicity (ADCC) of SCLC cells in vitro and in a murine SCLC xenograft model. We studied SCLC apoptosis and necrosis during ADCC and the activity and cleavage of caspase-3, caspase-9, and poly(ADP-ribose) polymerase (PARP). RESULTS: The bispecific molecule functions as a cross-linker between T cells and SCLC cells, induces T cell activation, and mediates ADCC of SCLC cells; 40% to 80% growth inhibition of SCLC cells mediated by the bispecific molecule at low effector to target cell ratios was achieved. Activation of T cells by the bispecific molecule resulted in significant increases in IFNgamma production and apoptosis and necrosis of SCLC cells associated with cleavage of PARP and caspase-3. Targeted immunotherapy with the bispecific molecule-armed human T cells significantly reduced SCLC tumor burdens in a mouse model. CONCLUSION: The bispecific molecule OKT3xAntag2 mediates growth inhibition and apoptosis of SCLC cells by activated T cells through activation and cleavage of caspase-3 and PARP in vitro and in vivo. Clinical trials of this bispecific molecule through adoptive transfer of ex vivo activated T cells in GRP receptor-positive tumors, such as SCLC, are warranted.

Animals↗
PubMed2006

Myeloid precursors and acute myeloid leukemia cells express multiple CD33-related Siglecs.

OBJECTIVES: CD33 is a cell surface marker of committed myelomonocytic precursors and circulating monocytes, and is also found on acute myeloid leukemia (AML) cells. CD33 belongs to a family of sialic acid-binding cell surface proteins named Siglecs, among which there are 7 other functional CD33-related Siglecs (CD33rSiglecs). We sought to characterize the spectrum of expression of the other CD33rSiglecs on bone marrow precursors and AML cells and asked if they can potentially serve as targets for therapy. METHODS: Cell surface CD33rSiglecs were analyzed by flow cytometry. The ability of certain anti-Siglec antibodies to target toxin-mediated cell killing of Siglec-expressing cell lines was characterized and compared. RESULTS: We demonstrate that Siglecs-3, -5, -6, -7, and -9 are expressed on subsets of normal bone marrow precursors, including promonocytes and myelocytes. Furthermore, most AML (but not ALL) cells express these Siglecs. There is substantial variability in Siglec type and expression level between cases, with each having a unique "CD33rSiglec fingerprint." Individual anti-Siglec antibodies along with a saporin toxin-conjugated secondary antibody can target myelomonocytic leukemia cells for death, and targeting of multiple Siglecs improves cell killing. Cytotoxicity was further enhanced by sialidase treatment of target cells, which improves antibody binding. We also confirmed that antibody binding induced rapid internalization of Siglecs from the cell surface, which is a requirement for cell killing via saporin. CONCLUSIONS: Multiple CD33rSiglecs are expressed on normal and malignant myelomonoyctic cells. Targeting these Siglecs, possibly in combinations, could improve anti-CD33 antibody therapy or be used as an alternative to anti-CD33.

Antibodies, Monoclonal↗
PubMed2005

Non-anthracycline based remission induction therapy for newly diagnosed patients with acute myeloid leukemia aged 60 or older.

We assessed remission rates and toxicity in 24 consecutive elderly (age>or=60) patients with untreated Acute myeloid leukemia (AML) who received the anthracycline-free combination of fludarabine, cytosine arabinoside and G-CSF (FLAG) as initial induction chemotherapy at our center. CR was achieved following one cycle of FLAG in 14 patients (58%). Another four patients cleared blasts from their bone marrow by day 30 without complete platelet recovery. Three patients died from infections prior to neutrophil recovery (12%). No other grade 3/4 toxicities and no clinically significant mucositis were seen. No significant association was found between age, WBC and cytogenetic risk group with likelihood of achieving CR. Fifteen patients proceeded to consolidation therapy and seven patients received a stem cell transplant (six autologous, one allogeneic). Primary induction with FLAG in elderly AML patients achieves a high remission rate without prohibitive mucosal or cardiac toxicity and may thus be considered as an alternative to standard anthracycline-based regimens in this setting.

Acute Disease↗
PubMed2005

Anti-CD33 monoclonal antibodies enhance the cytotoxic effects of cytosine arabinoside and idarubicin on acute myeloid leukemia cells through similarities in their signaling pathways.

OBJECTIVE: Chemotherapy agents (CA) such as cytosine arabinoside (ara-C), idarubicin (IDA), and etoposide (VP-16) are widely used in the treatment of acute myeloid leukemia (AML) However, their effects on signaling pathways leading to cytotoxicity have only been described recently. Ligation of the leukemia-associated antigen CD33 by anti-CD33 monoclonal antibody (mAb) also results in signaling events that induce a downregulation of cell growth. We examined the possibility that anti-CD33 mAb and CA might cooperate in mediation of growth inhibition in primary AML samples and AML cell lines. MATERIALS AND METHODS: We investigated two AML cells lines and 14 primary AML samples for their proliferative response ((3)H-thymidine incorporation), colony formation, and biochemical (Western blot analysis) to anti-CD33 mAb treatment combined with chemotherapy agents. RESULTS: CD33 ligation induced a significant increase in ara-C- or IDA- but not VP-16-or Bryostatin-mediated inhibition of proliferation and colony formation. Ara-C and IDA induced SHP-1 and SHP-2 protein tyrosine phosphatase (PTPs) phosphorylation and Lyn/SHP-1 complex formation, while VP-16 and Bryostatin did not. CD33 ligation, however, mediated phosphorylation of these PTPs and Syk/SHP-1 complex formations. Combined treatment of AML cells by ara-C or IDA with anti-CD33 mAb resulted in higher levels of SHP-1 phosphorylation. Reduction in SHP-1 by short interfering RNA abrogated these effects. CONCLUSION: These data suggest that combined incubation of leukemia cells with anti-CD33 mAb and ara-C or IDA, but not VP-16 or Bryostatin, independently triggers similar events in the downstream signaling cascade, and therefore leads to additive antiproliferative effects and enhanced cytotoxicity.

Antibodies, Monoclonal↗
PubMed2004

Small peptide analogs to stromal derived factor-1 enhance chemotactic migration of human and mouse hematopoietic cells.

Stromal cell-derived factor 1 (SDF-1) is a chemokine that binds to the CXCR4 receptor. Its functions include acting as a chemotactic factor for hematopoietic stem and progenitor cells. We recently reported the synthesis of a small cyclized peptide analog (31 amino acids) of the terminal regions of SDF-1 that had biological function comparable to the native molecule (67 amino acids). In the present study, we investigated the effects of SDF-1 analogs (CTCE0021 and CTCE0214) in the chemotactic migration of peripheral blood hematopoietic cells (lineage-negative and CD34(+) cells). Enhanced chemotaxis of normal and G-CSF-mobilized hematopoietic cells was observed with both SDF-1 analogs in a dose-dependent manner. The increases were statistically significant (p < or = 0.016 by one-way ANOVA) at analog concentrations of 50 to 100 microg/mL. Colony-forming progenitor cells were not affected by exposure to the analogs up to 100 microg/mL. When different doses of the SDF-1 analog CTCE0214 were administered to mice, significant increases in circulating hematopoietic cells (identified by flow cytometry as lineage(low/-), Sca-1(+), and c-kit(+)) were observed after a single injection of 75 microg per animal. The effect was apparent at 4 hours and became significant at 24 hours. These results suggest that SDF-1 analogs can be considered for mobilization of hematopoietic stem cells.

Amino Acid Sequence↗
PubMed2004

Inhibition of acute myeloid leukemia cell growth by mono-specific and bi-specific anti-CD33 x anti-CD64 antibodies.

Bi-specific anti-CD33 x anti-CD64 antibodies (BsAb) mediated more potent and longer-lasting inhibition of proliferation of human leukemia cell lines and primary acute myeloid leukemia (AML) samples compared to mono-specific anti-CD33 mAb. There were no differences between these two antibodies in cellular internalization over time. The inhibitory effect of BsAb was mimicked by a mouse IgG2a subclass mono-specific anti-CD33 mAb. These findings indicate that enhanced inhibition of proliferation was caused by simultaneous ligation of both CD33 and CD64 molecules. We conclude that inhibition of leukemia cell growth initiated by BsAb during prolonged exposure may have therapeutic value for the treatment of AML.

Acute Disease↗
PubMed2004

Targeting gastrin-releasing peptide receptors for cancer treatment.

Growth factor receptors play critical roles in cancer cell proliferation and progression. A number of such receptors have been targeted for cancer treatment by either a monoclonal antibody or a specifically designed small molecule to inhibit the receptor function. Bombesin/gastrin-releasing peptide receptors (BN/GRP-Rs) are expressed in a variety of cancer cells and have limited distribution in normal human tissue. Inhibition of BN/GRP-Rs has been shown to block small cell lung cancer growth in vitro. Early phase clinical trials targeting human GRP-R showed anti-cancer activity. This review will focus on the study of the distribution of BN/GRP-Rs in normal and malignant tissues, and various approaches to targeting BN-GRP-Rs for cancer diagnosis and treatment.

Animals↗
PubMed2003

Bombesin/gastrin-releasing peptide receptor: a potential target for antibody-mediated therapy of small cell lung cancer.

PURPOSE: Bombesin/gastrin releasing peptide (BN/GRP) is a growth factor for small cell lung cancer (SCLC). The receptor (R) for BN/GRP is overexpressed on SCLC cells and other solid tumors. BN/GRP and its receptor form an autocrine loop to promote tumor growth. We developed a novel immunotherapeutic approach targeting cell surface BN/GRP-R on SCLC cells and an immune trigger molecule on host immune effector cells to direct immune effector cells to SCLC cells and mediate targeted cancer cell destruction. Targeted immunotherapy combined with chemotherapy enhanced cell killing. EXPERIMENTAL DESIGN: We designed a synthetic BN/GRP antagonist (Antag 2) and constructed a bispecific molecule (BsMol), H22xAntag 2 (humanized monoclonal antibody) for FcgammaRI. We tested the binding of the BsMol to several SCLC cell lines, its ability to mediate cytotoxicity of SCLC by IFN-gamma-activated human monocytes with chemotherapy, and BsMol-mediated immunotherapy in an animal model of SCLC human xenograft. RESULTS: Common chemotherapy (cisplatin, etoposide, and paclitaxel) inhibited thymidine uptake into SCLC cells in a dose-dependent pattern. Antibody-dependent cellular cytotoxicity mediated by the BsMol inhibited thymidine uptake into SCLC cells and was largely dependent on E:T cell ratio. When SCLC cells were treated with antibody-dependent cellular cytotoxicity followed by exposure to chemotherapy agents an additional 25-40% inhibition of thymidine uptake into SCLC cells was observed consistently. With BsMol and IFN-gamma-activated human monocytes, tumor burdens were reduced significantly in immunodeficient mice bearing human SCLC xenografts. CONCLUSIONS: Combined chemotherapy and immunotherapy targeting BN/GRP-R with a BsMol significantly enhances targeted SCLC cell killing.

Animals↗
PubMed2003

The inhibitory effect of anti-CD33 monoclonal antibodies on AML cell growth correlates with Syk and/or ZAP-70 expression.

OBJECTIVES: Acute myeloid leukemia (AML) cells express the cell surface antigen CD33 that can function as a downregulator of cell growth, mediating growth arrest and apoptosis. The protein kinase Syk is an essential element in several cascades coupling certain antigen receptors to cell responses. Recently we reported that CD33 recruits Syk for its signaling in AML cell lines. In this study, we further investigated the mechanism(s) of Syk engagement in CD33 signaling in primary AML samples. METHODS: We investigated 25 primary AML samples for their proliferative response (3H-thymidine incorporation) and biochemical changes (Western blot analysis) to anti-CD33 mAb treatment. RESULTS: Proliferation studies demonstrated that 14 (56%) of AML samples were responsive (R) while 11 (44%) were nonresponsive (n-R) to inhibitory antibody activity. Seven of 25 AML samples (28%) expressed undetectable levels of Syk. However, cells from two of these patients expressed the ZAP-70 protein kinase. In Syk/ZAP-70(+) samples, CD33 ligation inhibited proliferation in 70% of cases, while none of the Syk/ZAP-70(-) samples was responsive. There were significant biochemical differences between responder and nonresponder AML populations. In responder samples, CD33 ligation induced phosphorylation of CD33 andSyk and formation of the CD33/Syk complex. In nonresponder samples, CD33 was not phosphorylated, and Syk was in complex with the SHP-1 protein phosphatase constitutively. CONCLUSIONS: Syk is an important component in the regulation of proliferation in AML cells. The differential response of AML cells to CD33 ligation is associated with the level of the Syk expression.

Antibodies, Monoclonal↗
PubMed2002

Development of allogeneic hematopoietic stem cell transplantation (HSCT).

The field of BMT has entered a new phase based on insights into basic molecular and cellular biology. The mechanism of cure mediated by allogeneic HSCT is now believed to be at least partially mediated by cellular attack against tumor-associated antigens. Better understanding of these cellular targets and the means of targeting them specifically will allow a more precise application of cellular therapy than is currently possible. This in turn may make it possible to design therapies that are increasingly selective without the collateral toxicities of GVHD, infection, and direct organ damage that currently are the limiting features of allogeneic HSCT as practiced until recently. However, it remains a challenge to demonstrate that disease-control using reduced intensity preparative regimens is at least comparable to that achieved by traditional myeloablative HSCT. This will require carefully controlled studies in each the major diseases that have shown sensitivity to the immune-mediated effects of HSCT. The chapters below will highlight progress towards the goals of elucidating the role of NST.

Animals↗
PubMed2002

Sequential modulation of growth factors: a novel strategy for adoptive immunotherapy of acute myeloid leukemia.

Evidence from allogeneic hematopoietic stem cell transplantation indicates a possible immune response against leukemia-associated antigens in patients with either acute myeloid leukemia (AML) or chronic myeloid leukemia (CML). However, autologous immune responses are less evident. We have developed a method using sequential modulation of growth factors (SMGF) to generate specific anti-AML T-cells from primary cultures of mononuclear cells (MNCs) from patients with AML. This culture method induces greater degrees of antigen presentation by inducing dendritic cell (DC) differentiation of AML in the presence of autologous lymphocytes, which are then expanded by interleukin (IL)-2 and costimulatory molecule ligation. MNCs consisting of 92.3% +/- 5.1% AML blasts and 3.4% +/- 3.2% CD3+ T-cells were obtained from AML patients (n = 12) and cultured in AIM-V medium with IL-4 and recombinant granulocyte-monocyte colony-stimulating factor. Recombinant IL-2 was added on day 8. On day 21, culture conditions were changed to anti-CD3/anti-CD28 monoclonal antibodies and IL-2. By day 42, 354 +/- 182-fold CD3+ T-cell expansion had occurred. Cytotoxic T-lymphocyte assays demonstrated that these T-cells caused significant lysis of autologous leukemia cells and AML cell lines, but not of cells of other lineages, in an HLA class I-dependent manner. Specific Vbeta subgroups (Vbeta3, -7, and -12a), possibly representing T-cell clones specific to AML-specific antigens, were expanded in the cultures of cells from 3 AML patients. SMGF can be used to induce and expand autologous T-cells with HLA class I-dependent antileukemia potential from the peripheral blood of AML patients. Adoptive transfer of these expanded T-cells to patients is a possible therapeutic approach for further study.

Acute Disease↗