Karen Rosell

A phase I trial of immunotherapy with intratumoral adenovirus-interferon-gamma (TG1041) in patients with malignant melanoma.

Aims: Interferon-gamma (IFN-γ) has been shown to upregulate MHC class I and II expression, and to promote generation of specific antitumor immune responses. We hypothesized that intratumoral administration of an IFN-γ gene transfer vector facilitates its enhanced local production and may activate effector cells locally. We conducted a phase I dose-escalation study of a replication-deficient adenovirus–interferon-gamma construct (TG1041) to determine safety and tolerability of intratumoral administration, in advanced or locally recurrent melanoma. Methods: Patients were enrolled at four successive dose levels: 107 infectious units (iu) (n=3), 108 iu (n=3), 109 iu (n=3), and 1010 iu (n=2) per injection per week for 3 weeks. TG1041 was injected in the same tumor nodule weekly in each patient. Safety, toxicity, local and distant tumor responses and biologic correlates were evaluated. Results: A total of 11 patients were enrolled and received the planned three injections per cycle. One patient with stable disease received a second cycle of treatment. A maximum tolerated dose was not reached in this study. No grade 4 toxicities were observed. Two grade 3 toxicities, fever and deep venous thrombosis were observed in one patient. The most frequently reported toxicities were grade 1 pain and redness at the injected site (n=8), and grade 1 fatigue (n=5) patients. Clinical changes observed at the local injected tumor site included erythema (n=5), a minor decrease in size of the injected lesion (n=5) and significant central necrosis by histopathology (n=1). Systemic effects included stable disease in one patient. Correlative studies did not reveal evidence of immunologic activity. Conclusion: Weekly intratumoral administration of TG1041 appears to be safe and well tolerated in patients with advanced melanoma.

Flavonoid effects on normal and leukemic cells.

Quercetin and flavopiridol, both flavonoids which influence oxidative milieu, proliferation, and apoptosis of various cell types, were examined for their effects on acute myelogenous leukemic cells and normal progenitors. Both quercetin and flavopiridol inhibited the growth and viability of various acute myelogenous leukemia (AML) cell lines and AML blasts isolated afresh from patients with AML of various subtypes. The effects on inhibition of proliferation and decreased viability were also significant in normal CD34+ cells isolated from normal marrow donors. In certain AML cases, the effects of flavopiridol appeared to be mediated through activation of caspase 3, offering one possible mechanism for the apoptosis evident after exposure to flavopiridol as measured by annexin V expression. These flavonoid compounds might find use in various therapeutic settings in AML.

Acute myelogenous leukemia—microenvironment interactions: Role of endothelial cells and proteasome inhibition

Abstract How leukemia progenitors interact with marrow microenvironment components is poorly understood. In this work, the effects of endothelial coculture on acute myelogenous leukemia (AML) blast survival is examined as are the effects of endothelial coculture on the impact of a cytotoxic agent such as cytarabine. Similar to marrow stromal cells, endothelial cells are able to increase survival and proliferation of AML blasts and to partially protect against cytarabine effects. The proteasome inhibitor, bortezomib, has inhibitory effects in multiple myeloma in part through effects on marrow stromal cells. Bortezomib has been found to inhibit AML blast survival. Such inhibition is less, however, in the presence of endothelial monolayers. Furthermore, AML blast transmigration through human umbilical vein endothelial cells is inhibited by bortezomib. These studies demonstrate that AML is subject to influence of endothelial cells and of agents such as bortezomib which have potential impact on AML interaction with the microenvironmental niche.

Response of Human CD34+ Cells to CXC, CC, and CX3C Chemokines: Implications for Cell Migration and Activation

Ultrastructural studies of marrow and examination of the in vivo processes of stem cell homing and mobilization show that multipotential hematopoietic progenitors are able to traverse endothelial cells. The regulation of this process by various classes of chemokines was studied in this report, using an in vitro model of transendothelial migration. Human umbilical vein endothelial cells (HUVECs) or bone marrow-derived endothelial cells (BMECs) were grown to confluence on 3-microm microporous membrane inserts and placed in 24-well culture plates. CD34(+) cells isolated from normal volunteer donor marrow by immunoadsorption or magnetic bead selection techniques were added to the inserts and various individual chemokines were added to the lower chamber of the culture plates in serum-free conditions. After 24 h, the percentage of transmigrated cells was determined. A mean of 8.5% of unfractionated marrow CD34(+) populations migrated, and all chemokines tested, with the exception of macrophage inflammatory protein-1alpha (MIP-1alpha), had some positive effect on this migration. The greatest effects were seen with stroma-derived factor-1alpha (SDF-1alpha) and stroma-derived factor-1beta (SDF-1beta), with lesser effects noted for other chemokines and cytokines. When the CD34(+) population was subselected for expression of CD38, a greater fraction of the CD38(-) cells migrated as compared to the CD38(+) fraction. CD34(+) cells isolated from mobilized peripheral blood and cord blood also migrated in response to chemokines. Chemokines of the CC, CXC, and CX(3)C classes as well as other hematopoietic cytokines may modulate the process of stem cell transmigration of endothelial cells. Further understanding of this process may help elucidate the mechanism of stem cell mobilization and homing.

Cytotoxicity of Algae Extracts on Normal and Malignant Cells

Algae preparations are commonly used in alternative medicine. We examined the effects of algae extracts on normal hematopoietic cells and leukemia cells. Ethanol extracts were prepared of Dunaliella salina (Dun), Astaxanthin (Ast), Spirulina platensis (Spir), and Aphanizomenon flos-aquae (AFA). Cell viability effects were completed by Annexin staining. Ast and AFA inhibited HL-60 and MV-4-11 whereas Dun and Spir had no effect. Primary AML blasts demonstrated increased apoptosis in AFA. Primary CLL cells showed apoptosis at 24 hours after exposure to Dun, Ast, Spir, and AFA. High AFA concentrations decreased viability of normal marrow cells. Normal CD34+ viability was inhibited by Dun. Dun and AFA inhibited BFU-E, but all extracts inhibited CFU-GM. Cell-cycle analysis of AML cell lines showed G0/G1 arrest in the presence of AFA. These data suggest that algae extracts may inhibit AML cell lines and leukemia blasts, but they may also have potential inhibitory effects on normal hematopoiesis.

Effects of the farnesyl transferase inhibitor R115777 on normal and leukemic hematopoiesis

Patients with acute myelogenous leukemia or myelodysplastic syndrome may respond to farnesyl transferase inhibitors (FTIs) with partial or complete response rates noted in about 30% of such patients. FTIs prevent the attachment of a lipid farnesyl moiety to dependent proteins prior to their insertion into the plasma membrane and thereby prevent activity of these prenylation-dependent proteins, but their mechanism of tumor suppression remains unknown. Many patients receiving FTIs do experience myelosuppression. In this work, the in vitro effects of the FTI, R115777 on normal and leukemic hematopoiesis have been examined as have its effects on apoptosis induction and cell cycle profile in both leukemic blasts and normal CD34+ cells. R115777 was inhibitory to normal CD34+ cell proliferation and to leukemic blast cells, but did not affect long-term culture initiating cell frequency nor NOD-SCID reconstituting capacity. No induction of apoptosis or cell cycle changes were noted in AML blasts. These data suggest that myelosuppression with R115777 occurs largely at the intermediate to late progenitor stage of hematopoiesis and that cyclic use might avoid long-term marrow suppression.

A phase I study of decitabine and rapamycin in relapsed/refractory AML

A phase I study utilizing decitabine (DAC) followed by the mammalian target of rapamycin (mTOR) inhibitor, rapamycin, in patients with relapsed/refractory adult AML was undertaken to assess safety and feasibility. Patients received DAC 20mg/m(2) intravenously daily for 5 days followed by rapamycin from day 6 to day 25 at doses of 2 mg, 4 mg, and 6 mg/day in a standard 3+3 dose escalation design. Twelve patients completed treatment for safety evaluation. Maximum tolerated dose (MTD) was not reached, and except for grade 3 mucositis in 4 patients, no other significant unexpected non-hematologic toxicities have occurred indicating safety of this regimen. This trial is registered at clinical trials.gov as NCT00861874.

Proteasome inhibition in myelodysplastic syndromes and acute myelogenous leukemia cell lines.

In this work, effects of bortezomib on apoptosis, clonal progenitor growth, cytokine production, and NF-κB expression in patients with MDS with cytopenias requiring transfusion support are examined. Bortezomib increased apoptosis in marrow mononuclear cells but had no effects on CFU-GM, BFU-E, or CFU-L content. No consistent effects on NF-κB activation in vivo were noted. To further define the role of bortezomib in AML and MDS, we examined it in combination with several targeted agents and chemotherapeutic agents in vitro. Combinations with arsenic trioxide, sorafenib, and cytarabine demonstrated synergistic in vitro effects in AML cell lines.

Effects of anti-oxidants on normal and leukemic hematopoiesis

Abstract Various compounds affecting oxidation status such as nitric oxide (NO), flavones, and flavonoids have been reported to have antiproliferative and specifically, antileukemic effects. We have examined the effects of NO donors and inhibitors as well as that of quercetin and flavopiridol on myeloid leukemic cells. The NO donor SNAP decreased both proliferation and viability of AML cell lines and primary blasts from AML patients. With leukemic cell lines KG1, KG1a, THP-1, and U937, quercetin decreased the growth and viability in a dose-dependent manner. As early as 4 to 6 hours, quercetin also increased expression on Annexin V in both these cell lines. Flavopiridol also decreased proliferation and viability of each of these cell lines. With fresh myeloid leukemic cells, quercetin and flavopiridol both decreased the viability and proliferation of blast cells in vitro. Wide sample to sample variation was noted, and the inhibitory effects were noted both in the presence and absence of exogenous growth factors. The percentage of cells undergoing apoptosis was higher in the absence of growth factor at all time points, and the effects of flavopiridol on apoptosis induction were more pronounced in the absence of growth factors. Apoptosis with flavopiridol was correlated with activated caspase-3 expression. In order to determine the effect of flavopiridol and quercetin on normal CD34+ cells, cells isolated from marrow of normal donors via a MiniMACS (Miltenyi) CD34+ cell isolation procedure were cultured in 1- to 100 μm flavopiridol or quercetin. Inhibitory effects of both quercetin and flavopiridol were seen at 48 to 72 hours of culture. While the flavonoids, quercetin and flavopiridol and the NO donor, SNAP, have anti-leukemic effects on leukemic cell lines and leukemic blasts and progenitors in culture, they also appear to be inhibitory to normal multipotential hematopoietic cells and clonogenic progenitors. Use of these agents either ex vivo or in future clinical trials would ideally require further exploitation of differential sensitivity of leukemic and normal progenitors to such agents.