scholarly journals Evaluation of Carcinogenic/Co-carcinogenic Activity of Chikusaku-eki, a Bamboo Charcoal By-product Used as a Folk Remedy, in BALB/c 3T3 Cells

2002 ◽  
Vol 25 (8) ◽  
pp. 1026-1029 ◽  
Author(s):  
Yuki Kimura ◽  
Shiho Suto ◽  
Masaaki Tatsuka
Author(s):  
D. C. Hixson

The abilities of plant lectins to preferentially agglutinate malignant cells and to bind to specific monosaccharide or oligosaccharide sequences of glycoproteins and glycolipids make them a new and important biochemical probe for investigating alterations in plasma membrane structure which may result from malignant transformation. Electron and light microscopic studies have demonstrated clustered binding sites on surfaces of SV40-infected or tryp- sinized 3T3 cells when labeled with concanavalin A (con A). No clustering of con A binding sites was observed in normal 3T3 cells. It has been proposed that topological rearrangement of lectin binding sites into clusters enables con A to agglutinate SV40-infected or trypsinized 3T3 cells (1). However, observations by other investigators have not been consistent with this proposal (2) perhaps due to differences in reagents used, cell culture conditions, or labeling techniques. The present work was undertaken to study the lectin binding properties of normal and RNA tumor virus-infected cells and their associated viruses using lectins and ferritin-conjugated lectins of five different specificities.


Author(s):  
R. W. Tucker ◽  
N. S. More ◽  
S. Jayaraman

The mechanisms by which polypeptide growth factors Induce DNA synthesis in cultured cells is not understood, but morphological changes Induced by growth factors have been used as clues to Intracellular messengers responsible for growth stimulation. One such morphological change has been the transient disappearance of the primary cilium, a “9 + 0” cilium formed by the perinuclear centriole in interphase cells. Since calcium ionophore A23187 also produced both mitogenesis and ciliary changes, microtubule depolymerization might explain ciliary disappearance monitored by indirect immunofluorescence with anti-tubulin antibody. However, complete resorption and subsequent reformation of the primary cilium occurs at mitosis, and might also account for ciliary disappearance induced by growth factors. To settle this issue, we investigated the ultrastructure of the primary cilium using serial thin-section electron microscopy of quiescent BALB/c 3T3 cells before and after stimulation with serum.


1987 ◽  
Vol 26 (01) ◽  
pp. 13-23 ◽  
Author(s):  
H. W. Gottinger

AbstractThe purpose of this paper is to report on an expert system in design that screens for potential hazards from environmental chemicals on the basis of structure-activity relationships in the study of chemical carcinogenesis, particularly with respect to analyzing the current state of known structural information about chemical carcinogens and predicting the possible carcinogenicity of untested chemicals. The structure-activity tree serves as an index of known chemical structure features associated with carcinogenic activity. The basic units of the tree are the principal recognized classes of chemical carcinogens that are subdivided into subclasses known as nodes according to specific structural features that may reflect differences in carcinogenic potential among chemicals in the class. An analysis of a computerized data base of known carcinogens (knowledge base) is proposed using the structure-activity tree in order to test the validity of the tree as a classification scheme (inference engine).


Author(s):  
Stefan Dimov ◽  
Anelia Ts. Mavrova ◽  
Denitsa Yancheva ◽  
Biliana Nikolova ◽  
Iana Tsoneva

Aims: The purpose was the synthesis of some new thienopyrimidines derivative of 1,3-disubstituted benzimidazoles and the evaluation of their cytotoxicity towards MDA-MB-231 and MCF-7 cell lines as well 3T3 cells. Background: An overexpression or mutational activation of TK receptors EGFR and HER2/neu are characteristic for tumors. It has been found that some thieno[2,3-d]pyrimidines exhibit better inhibitory activity against epidermal growth factor receptor (EGFR/ErbB-2) tyrosine kinase in comparison to aminoquinazolines. Breast cancer activity towards MDAMB-231 and MCF-7 cell lines by inhibiting EGFR was revealed by a novel 2-arylbenzimidazole. This motivated the synthesis of new thienopyrimidines possessing benzimidazole fragment in order to evaluate their cytotoxicity to the above mentioned cell lines. Objective: The objectives were the design and synthesis of a novel series thieno[2,3-d]pyrimidines bearing biologically active moieties as 1,3-disubstituted-benzimidazole heterocycle structurally similar to diaryl ureas in order to evaluate their cytotoxicity against MDA-MB-231, MCF-7 breast cancer cell lines. Methods: N,N-disubstituted benzimidazole-2-one carbonitriles were synthesized by Aza-Michael addition and used as precursors to generate some of the new thieno[2,3-d]pyrimidines in acidic medium. The interaction of chloroethyl-2- thienopyrimidines and 2-amino-benzimidazole resp. benzimidazol-2-one nitriles under solid-liquid transfer catalysis conditions lead to obtaining of new thienopyrimidines. MTT assay for cells survival was performed in order to establish the cytotoxicity of the tested compounds. Fluorescence study was used to elucidate some aspect of mechanism. Results: The effect of nine of the synthesized compounds was investigated towards MDA-MB-231 and MCF-7 cells as well as to 3T3 cells. Thieno[2,3-d]pyirimidine-4-one 16 (IC50 – 0.058 μM) and 21 (IC50 – 0.029 μM) possess high cytotoxicity against MDA-MB-231 cells after 24h. The most toxic against breast cancer MCF-7 cells was compounds 21 (IC50 – 0.074 μM), revealing lower cytotoxicity towards mouse fibroblast 3T3 cells with IC50 – 0.20 μM. SAR analisys was performed. Fluorescence study of the treatment of MDA-MB cells with compound 21 was carried out in order to clarify some aspects of mechanism of action. Conclusion: The relationship between cytotoxicity of compounds 14 and 20 against MCF-7 and 3T3 cells can suggest a similar mechanism of action. The antitumor potential of the tested compounds proves the necessity for further investigation to estimate the exact inhibition pathway in the cellular processes. The fluorescence study of the treatment of MDA-MB cells with compound 21 showed a rapid process of apoptosis.


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