Effects of okadaic acid and vanadate on TPA-induced monocytic differentiation in human promyelocytic leukemia cell line HL-60

Carcinogen-induced early molecular events and its implication in the initiation of chemical hepatocarcinogenesis in rats: Chemopreventive role of vanadium on this process

Carcinogen-induced formation of DNA adducts and other types of DNA lesions are the critical molecular events in the initiation of chemical carcinogenesis and modulation of such events by chemopreventive agents could be an important step in limiting neoplastic transformation in vivo. Vanadium, a dietary micronutrient has been found to be effective in several types of cancers both in vivo and in vitro and also possesses profound anticarcinogenicity against rat models of mammary, colon and hepatocarcinogenesis. Presently, we report the chemopreventive potential of vanadium on diethylnitrosamine (DEN)-induced early DNA damages in rat liver. Hepatocarcinogenesis was induced in male Sprague-Dawley rats with a single, necrogenic, intraperitoneal (i.p.) injection of DEN (200 mg/kg body weight) at week 4. There was a significant induction of tissue-specific ethylguanines, steady elevation of modified DNA bases 8-hydroxy-2'-deoxyguanosines (8-OHdGs) (P<0.0001; 89.93%) along with substantial increment of the extent of single-strand breaks (SSBs) (P<0.0001) following DEN exposure. Supplementation of 0.5 ppm of vanadium throughout the experiment abated the formations of O(6)-ethylguanines and 7-ethylguanines (P<0.0001; 48.71% and 67.54% respectively), 8-OHdGs (P<0.0001; 81.37%), length:width (L:W) of DNA mass (P<0.01; 62.12%) and the mean frequency of tailed DNA (P<0.001; 53.58%), and hepatic nodulogenesis in preneoplastic rat liver. The study indicates that 0.5 ppm vanadium is potentially and optimally effective, as derived from dose-response studies, in limiting early molecular events and preneoplastic lesions, thereby modulating the initiation stage of hepatocarcinogenesis. Vanadium is chemopreventive against DEN-induced genotoxicity and resulting hepatocellular transformation in rats.

The use of cytochemistry, immunophenotyping, flow cytometry, and in vitro differentiation to determine the ontogeny of a canine monoblastic leukemia

We evaluated the utility of cytochemistry, immunophenotyping, flow cytometry, and in vitro culture with forced differentiation of leukemic cells as diagnostic aids to identify the malignant cell ontogeny in a dog with leukemia. A tentative diagnosis of monoblastic leukemia was established by microscopic examination of Romanowsky-stained blood smears and bone marrow aspirate smears. This diagnosis also was supported by the light scatter signature that identified the blast cells as large, non-granular monocytic cells using a CellDyn 3500 automated hematology analyzer; as well as by the detection of N-butyrate esterase and the lack of choloroacetate esterase or leukocyte peroxidase by cytochemical staining. Subsequently, leukemic cells were isolated from the dog's peripheral blood and placed into tissue culture or cryopreserved. The leukemic cells grew in suspension cultures and proliferated spontaneously for up to 4 days. By day 7, proliferation was negligible. Upon culture with conditioned supernatant using mitogen-stimulated human T cells as a source of cytokines, an increased proportion of cells entered S phase by day 2 of culture; however, proliferation declined markedly by day 4, at which time the cells had apparently differentiated to adherent, vacuolated macrophages. The cytokine-stimulated leukemic cells were positive for the monocyte/macrophage specific markers alpha-1-antitrypsin, alpha-1-antichymotrypsin, lysozyme, CD14, MHC class II, and calprotectin, an antigen found in differentiated macrophages and granulocytes. Despite the strong tendency of the leukemic cells towards monocytic differentiation, our results suggested that they retained some features of a myelomonocytic precursor. These data show that cytochemistry, immunophenotyping, flow cytometry, and in vitro differentiation of canine leukemia cells are useful tools for confirming the lineage of malignant hematopoietic cells.