No abstract

Selective methods for the synthesis of C(2) monoallyl and C(2) diallyl derivatives of lupane terpenoids were developed. The methods involve reactions of allyl halides with potassium enolates or potassium enoxy(triethyl)borates generated in situ from 3 oxolupanes (betulonic acid, 3 oxo betulin) under the action of KN(SiMe 3 ) 2 , KH, or Bu t OK with subsequent addition of Et 3 B. The use of the reagent KN(SiMe 3 ) 2 -Et 3 B in 1,2 dimethoxyethane ensured the kinet ically controlled generation of enolate anions, which yielded 2β propenyl lupane terpenoids with high stereoselectivity. Reactions of 3 oxolupanes with excesses of Bu t OK and allyl halide (2.5 equiv.) gave 2,2 bisallylation products. In vitro studies revealed that one of the latter efficiently suppresses the NO production by activated macrophages and has an antitumor effect on Ehrlich carcinoma and P 815 mastocytoma cell lines.

The suppressor activity of bone marrow cells not adhering to plastic is shown to appreciably increase after their 48-hour joint preincubation with mastocytoma P-815 supernatant or WEHI-3 myelomonocytic strain and to be unchanged after incubation with supernatants of K-2 erythroleukemic strain or Ehrlich's ascitic carcinoma. P-815, WEHI-3, and K-2 tumors are shown to produce factors characterized by colony-stimulating activity. Key Words: suppressor cells; tumor; colony-stimulating activityThe so-called natural suppressor cells (NSC) in the bone marrow (BM) are known to inhibit the proliferation of immunocompetent and tumor ceils in vitro by releasing a soluble suppressive factor [5][6][7]10] and in vivo [3,6]. NSC do not possess markers of mature immunoeompetent cells and belong to the BM fraction not adhering to plastic [1]. Experiments with different tumor growth models have shown that the development of a malignant process goes along with an appreciable activation of bone marrow NSC [3,4,6,9,13] and their appearance in the spleen [10,13]. Activation of these cells is associated with the direct influence of colonystimulating factors produced by tumors of many types [14]. Co-incubation of granuloeyte-maerophagal colony-stimulating factor (GM-CSF) or interleukin-3 with normal murine BM cells sharply increases the activity of NSC [12,14]. Tumors are known to vary in their ability to activate bone marrow NSC in vitro. For example, cocultivation of Lewis' pulmonary adenocarcinoma supernatant The purpose of this work was to study the suppressor-inducing and colony-stimulating activities of the factors produced in vitro by different types of tumor eeUs. MATERIALS AND METHODSExperiments were carded out with BALB/c and DBA/2 mice aged 2 to 3 months bred at the Research Laboratory for Experimental Biomedical Simulation, Tomsk Research Center, Russian Academy of Medical Sciences. Ehrlich's adenocarcinoma (in BALB/c mice) and P-815 mastocytoma (in DBA/2 mice) were induced by an intraperitoneal graft of 2x106 tumor cells. K-2 and WEHI-3 cell lines were maintained in vitro in complete culture medium.Cells were cultured in RPMI-1640 medium containing 2 mM HEPES buffer, 2 mM L-glutamine, 10% fetal calf serum (Flow), 5x10 -5 M 2-mercaptoethanol (Fluka), 100 U/ml penicillin, and 100 ~tg/ml streptomycin.

Natural suppressor cells from the bone marrow of intact animals and mice with Th1- and Th2-dependent immune response largely suppressed the production of Th1 (IFN-gamma, IL-2) and Th2 cytokines (IL-4). Antiproliferative activity of natural suppressor cells from intact and immunized animals was mediated by NO. Proliferation of Th1 cells was suppressed greater than that of Th2 cells. This selective effect of natural suppressor cells on the proliferation of target lymphocytes was due to higher stimulatory potential of Th1 cells (in comparison with Th2) towards natural suppressor cells.