Chemoimmunotherapy of cancer: potentiated effectiveness of granulocyte-macrophage colony-stimulating factor and ifosfamide derivative CBM-4A.

The effectiveness of combined chemoimmunotherapy with ifosfamide derivative CBM-4A and granulocyte-macrophage colony-stimulating factor (GM-CSF) was investigated in two experimental tumor models, 3MC-induced MHC class I+ sarcoma Mc12 and HPV16 E6/E7 oncogene-induced MHC class I- carcinoma MK16, transplanted in syngeneic mice. Treatment of Mc12 and MK16 tumor-bearing mice with GM-CSF or CBM-4A alone produced moderate anti-tumor effects. However, when the tumor-bearing mice were first treated i.p. with a single dose of CBM-4A (150 mg/kg) and three days later peritumorally with five daily doses of GM-CSF (100 ng/day), substantially stronger tumor-inhibitory effects were observed. The results indicate that in both, MHC class I+ and MHC class I- tumors, the combined chemoimmunotherapy can inhibit tumor progression more effectively than GM-CSF therapy or chemotherapy alone, and they suggest that GM-CSF should be considered as adjuvant to chemotherapy in clinical trials with HPV 16-associated neoplasms.

Synthesis, and cytotoxic activity of some novel indolo[2,3-b]quinoline derivatives: DNA topoisomerase II inhibitors.

A series of new 5H-indolo[2,3-b]quinoline derivatives bearing methoxy and methyl groups at C-2 and C-9 was synthesized (according to the modified Graebe-Ullmann reaction). These compounds were evaluated for their antimicrobial and cytotoxic activity and tested as inhibitors of DNA topoisomerase II. Lipophilic and calf thymus DNA binding properties of these compounds were also established. In the SAR studies we used quantum-mechanical methodology to analyze the molecular properties of the drugs. All of the 5H-indolo[2,3-b]quinolines tested were found to inhibit the growth of gram-positive bacteria and pathogenic fungi at MIC ranging between 2.0 and 6.0 microM. They showed also cytotoxic activity in vitro against several human cancer cell lines of different origin (ID50 varied from 0.6 to 1.4 microM), and stimulated the formation of topoisomerase-II-mediated pSP65 DNA cleavage at concentration between 0.2 and 0.5 microM. The most active indolo[2,3-b]quinolines which had the greatest contribution to the increase in the Tm of DNA displayed also the highest DNA binding constants and the highest cytotoxic activity. The differences in DNA binding properties and cytotoxic activity seem to be more related to steric than electrostatic effects.

[Antitumor effects of cytokines with immunomodulatory activity]. / Efekt przeciwnowotworowy cytokin o aktywnosci immunomodulatorowej.

The attempts to augment the immune responses in patients with solid tumors have been undertaken since long time ago. Recognition of the nature and biologic functions of cytokines and their receptors was the turning point in the studies on potential use of various immunotherapeutics. The availability of genetically engineered recombinant preparations enabled conducting basic and applied studies on a wide scale. There are numerous Phase I and II clinical trials ongoing in patients with melanoma, renal cell carcinoma, bronchogenic and digestive tract cancers, leukemias as well as other malignancies. Several cytokine preparations were shown to be quite toxic upon systemic application; at present they are more frequently used in loco regional (peritumoral) administration. More recently, a variety of tumor cells or tumor infiltrating lymphocytes (TIL) have been genetically engineered by transfection with different cytokine genes to yield "autovaccines". When applied locally they can be the source of cytokines, which in turn might be beneficial for the organism by unsettling the tumor-host balance. Cytokines are used in mono- and multidrug therapy in combinations with other cytokine or cytostatics. The colony-forming stimulating factors that stimulate proliferation of hematopoietic cells and induce their differentiation have found their application (e.g. GM-CSF or G-CSF) in enhancing the bone marrow renewal after chemo- and radiotherapy in cancer patients. They are also applied after bone marrow transplantation in patients with myelogenous leukemias. The results of immunotherapeutic approaches in cancer treatment are far from expected. Nevertheless, they gave us the fundamental insight into the complexity of tumor-host relationship.

Antitumor activity evaluation of bromine-substituted analogues of ifosfamide. I. Stereodifferentiation of biological effects and selection of the most potent compounds.

The series of 9 compounds, including 3 racemates and 6 enantiomers of bromine-substituted analogues of ifosfamide (bromo-, chlorobromo- and dibromofosfamides) have been evaluated for antitumor activity against L1210 leukemia, Lewis lung carcinoma and B16 melanoma in mice. Effective and curative doses of tested compounds were estimated on the basis of computer-assisted elaboration of the dose-effect curves obtained from experimental data. Two oxazaphosphorine drugs, ifosfamide and its congener cyclophosphamide, were used as referentials. Elementary toxicity studies were conducted in parallel in healthy animals and lethal doses were determined. Selection of the most potent compounds was based on the comparison of their therapeutic indices, calculated from the ratio of lethal to effective doses. In effect four compounds which have been shown therapeutically more effective than both referential drugs, were selected for further evaluation in mice bearing advanced tumours. Stereodifferentiation of evaluated biologic effects favouring S(-) isomers was observed in all three groups of compounds. Preliminary observation was also made indicating significant lethality reduction after per os administration of selected agents, which was not paralleled by diminution of their antitumor effectivity.

Studies on antitumor and myelotoxic effect of Ledakrin and its selected analogues.

Ledakrin (Nitracrine) and its three analogues (C-846, C-857, C-1006) selected in primary in vitro and in vivo screening systems have been tested for antitumor activity in Lewis lung carcinoma, B16 melanoma of 16/C mammary adenocarcinoma bearing mice. Their effect on mouse bone marrow stem cells has also been evaluated by means of CFU-S technique. None of the tested compounds, including Ledakrin, revealed anti-tumor activity. Their bone marrow toxicity was minimal and comparable with that of Bleomycin.

Preparation of anti-cea and anti-goat gamma-globulin sera for radioimmunologic assay of carcinoembryonic antigen.

Goats were immunized with purified carcinoembryonic antigen, and the suitability of the antisera for clinical assays of carcinoembryonic antigen was characterized. Reactivity of equine sera to goat gamma-globulin as a precipitating factor in the radioimmunologic double antibody technique was also evaluated.