title: Cytogenetic analyses of Azadirachtin reveal absence of genotoxicity but marked antiproliferative effects in human lymphocytes and CHO cells in vitro.
abstract: In this work we have examined the genotoxic potential of the bioinsecticide Azadirachtin A (AZA) and its influence on cell proliferation on human lymphocytes and Chinese Hamster ovary (CHO) cells. AZA genotoxicity was assessed by the analysis of chromosomal aberrations and sister chromatid exchanges (SCEs) in the absence and presence of rat liver S9 metabolism. Primary DNA damage was also investigated by means of the comet assay. The results obtained clearly indicate that AZA is not genotoxic in mammalian cells. On the other hand, AZA proved to interfere with cell cycle progression as shown by modulation of frequencies of first (M1) and second division (M2) metaphases detected by 5-Bromo-2'-deoxyuridine labeling. Accumulation of M1 metaphases were more pronounced in human lymphocytes. In the transformed CHO cell line, however, significant increases of multinucleated interphases and polyploid cells were observed at long treatment time. At higher dose-levels, the incidence of polyploidy was close to 100%. Identification of spindle structure and number of centrosomes by fluorescent immunostaining with α- and γ-tubulin antibodies revealed aberrant mitoses exhibiting multipolar spindles with several centrosomal signals. These findings suggest that AZA can act either through a stabilizing activity of microtubules or by inhibition of Aurora A, since both mechanisms are able to generate genetically unstable polyploid cells with multipolar spindles and multinucleated interphases.
authors.affiliation: Dipartimento di Scienze Ecologiche e Biologiche, Università degli Studi della Tuscia, Largo dell'Università, 01100 Viterbo, Italy. mosesso@unitus.it
authors.forename: Pasquale
authors.initials: P
authors.lastname: Mosesso
authors.forename: Lothar
authors.initials: L
authors.lastname: Bohm
authors.forename: Gaetano
authors.initials: G
authors.lastname: Pepe
authors.forename: Mario
authors.initials: M
authors.lastname: Fiore
authors.forename: Alice
authors.initials: A
authors.lastname: Carpinelli
authors.forename: Gerd
authors.initials: G
authors.lastname: Gäde
authors.forename: Siddavaram
authors.initials: S
authors.lastname: Nagini
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ottavianelli
authors.forename: Francesca
authors.initials: F
authors.lastname: Degrassi
mesh_terms: D000818:Animals; D064096:Aurora Kinase A; D064127:Aurora Kinases; D016466:CHO Cells; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D002869:Chromosome Aberrations / Q000139:chemically induced; D020552:Comet Assay; D006224:Cricetinae; D003412:Cricetulus; D020732:Cytogenetic Analysis; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007150:Immunohistochemistry; D007306:Insecticides / Q000378:metabolism / Q000633:toxicity*; D036701:Limonins / Q000378:metabolism / Q000633:toxicity*; D008099:Liver / Q000378:metabolism; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D009152:Mutagenicity Tests; D011123:Polyploidy; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D012854:Sister Chromatid Exchange / Q000187:drug effects; D008941:Spindle Apparatus / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors
chemical_list: D007306:Insecticides; D036701:Limonins; C576920:Aurka protein, rat; D064096:Aurora Kinase A; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; C010329:azadirachtin