Limits of stimulation of proliferation and differentiation of bone marrow cells of mice treated with swainsonine

The limits of stimulation of the immunomodulatory alkaloid swainsonine (8αβ-indolizidine-1α,2α,8β-triol) were studied in inbred C57BL/6 mice for potential support of intense high dose cancer chemotherapy and/or radiation because of its attractive pharmacologic profile on the hematopoietic system. Specifically, the effects of swainsonine on bone marrow cellularity and on in vitro progenitor cell proliferation to total colony forming units (CFU) and differentiation to different lineages were studied as a function of number of days post drug administration. The lineages evaluated were colony forming units-granulocyte-macrophage (CFU-GM), erythroid-burst forming units (BFU-e) and CFU-granulocyte-erythrocyte-monocyte-megakaryocyte (CFU-GEMM or CFU-Mix). Groups of mice were treated with swainsonine or plain vehicle, phosphate buffered saline for 10 consecutive days. The effects of these agents on the hematopoietic system were studied up to 60 days following their discontinuation. The magnitude of the effects of swainsonine on bone marrow system gradually declined with increasing duration of days following its discontinuation. Nevertheless, its residual stimulatory effects on bone marrow cellularity, total CFU, CFU-GM, BFU-e and CFU-Mix continued to be significant (P\u3c0.0001) up to 45, 50, 50, 55 and 50 days, respectively, compared to those of diluent buffer or untreated controls. Since cancer chemotherapeutic agents or radiation are normally given in schedules and/or cycles, these results strongly suggest that swainsonine effects are sustained long enough to potentially support and facilitate hematopoietic recovery during anti-cancer cytotoxic treatment. © 2003 Elsevier B.V. All rights reserved

Activated eosinophils infiltrate MCF-7 breast multicellular tumor spheroids

Background: Previous studies in our laboratory have shown that activated eosinophils and eosinophilic cell lines inhibit the in vitro growth of MCF-7 breast tumor cells. We have also shown that IL-4 and IL-5 partiaIly inhibit MCF-7 growth in vitro. In this study MCF-7 multicellular tumor spheroids (MTS) were developed to study the effect of eosinophils and IL-4 on tumor growth. Materials and Methods: Hypo- and hyperdense metrizamide density gradient fractions of eosinophils from peripheral blood of individuals with mild to moderate esoinophilia were co-cultured with 2-day-old MCF-7 MTS in medium containing bacto agar overlay at 37°C. Results: Light microscopic analyses revealed the attachment of eosinophil effector cells to the spheroid borders. Moreover, the culture media was greater than 90% devoid of effector cells. At six days post co-culture, very large spheroids were observed in both test and control dishes; however the necrotic cores in the co-cultures were more intense and larger than in the control. When MCF-7 tumor cells (1 × 106) were pretreated with IL-4 at 0.5 ng/ml, there was a dramatic decrease in the number of spheroids formed. Conclusion: These data strongly indicate that cytokines like IL-4 and perhaps other eosinophil mediators are capable of killing and inhibiting tumor growth; they suggest that tumor infiltrating eosinophils can degranulate and release toxic inhibitory factors into the tumor milieu which destroy the surrounding tumor. These observations, along with the use of the eosinophil: MTS tumor model provide a unique model system for in depth studies of the role of eosinophils and the cytokines they produce in breast cancer and may offer potential therapeutic implications

Swainsonine stimulates bone marrow cell proliferation and differentiation in different strains of inbred mice

The immunomodulatory alkaloid swainsonine (8αβ-indolizidine-1α,2α,8β-triol) has potential for overcoming the bone marrow suppressive effects of cancer chemotherapeutic drugs and radiation. The effect of swainsonine on bone marrow cellularity was evaluated in four different strains (C57BL/6; C3H-HEN; Balb/C and DBA-2 mice) of inbred mice subjected to multiple doses of the alkaloid. Swainsonine treatment stimulated bone marrow cell proliferation in all strains of mice. Examination of the peripheral blood did not reveal any increase in total leukocyte count. In vitro assessment of total colony-forming unit (CFU) capacity of bone marrow cells showed a two- to eight-fold increase in swainsonine treated mice of different strains compared to their corresponding controls given sham injections of physiological saline. Swainsonine induced increase in CFU capacity of bone marrow cells should find clinical application in cancer treatment with chemotherapeutic agents and radiation. © 2002 Elsevier Science Ltd. All rights reserved

Inhibition of prostate cancer cell growth by activated eosinophils

BACKGROUND. Host Immune response to prostate cancer primarily involves the CTL and NK effector cells. Recent immunotherapeutic strategies incorporating cytokine genes into the tumor cell and/or dendritic cells have had encouraging results. In this study, we describe the inhibitory activity of a third potential effector cell, the eosinophil, against DU 145 and PC-3 prostate tumor cells growth in vitro. METHODS. Subconfluent monolayer cultures of DU 145 and PC-3 cells were incubated with peripheral blood eosinophils from allergic or asthmatic individuals and also with eosinophil cultured supernatants. Newly established eosinophil cell lines were also studied. After harvesting, the plates were washed and stained with Hematoxylin/eosin (H/E) then photographed. The combination of monolayer cell growth inhibition and colony formation inhibition assays were used to evaluate eosinophil inhibitory activity. In the colony formation inhibition assay one hundred cells per well in 6-well plates were incubated overnight, after which peripheral blood eosinophils, conditioned media and cytokines, IL-4 and TNF-α were added. The plates were harvested after 10 days incubation period. Colonies were stained and counted. RESULTS. Hypo- and hyperdense peripheral blood eosinophils from allergic and asthmatic individuals as well as eosinophil cell lines established from these subpopulations inhibited both DU 145 and PC-3 cell growth at 58-78% and 10-38%, respectively. IL-5 up-regulated eosinophil cell line activity by 21-24%. The conditioned media which contained the released mediators of activated eosinophils were potent in their actions on both DU 145 and PC-3, inhibiting colony formation by as much as 90-100%. CONCLUSION. These results clearly demonstrate the inhibitory potential of activated eosinophils and their released soup of mediators and therefore support the hypothesis that eosinophils may participate in host response to prostate cancer together with CTLs and NK cells. Furthermore, this study offers insights into possible strategies for enhancing eosinophilic activity in prostate cancer. © 2003 Wiley-Liss, Inc

Recruitment Experience in the First Phase of the African American Hereditary Prostate Cancer (AAHPC) Study

Abstract available at publisher's web site.http://dx.doi.org/10.1016/S1047-2797(00)00194-