Inhibition of mitosis and induction of apoptosis in MG63 human osteosarcoma-derived cells in vitro by surface proteins from Actinobacillus actinomycetemcomintans.
Gentle saline extraction releases a heterogeneous mixture of proteins associated with the cell surface of Actinobacillus actinomycetemcomintans, termed the surface protein fraction (SF). Some SF components are biologically active and may modulate cell behaviour in a manner of putative importance in the aetiology of periodontitis. To further characterize this activity, the ability of the SF to induce mitosis and apoptosis in MG63 cells was investigated. Cells were plated at 10(3)-10(4) cells/cm(2) and allowed to attach before culture in the serum-free medium in the presence of 25 microg/ml SF for 2-24 h. The apoptotic and mitotic figures present were counted and the results expressed as an apoptotic or mitotic index. The apoptotic and mitotic compartments were very small, but there was an inverse correlation between mitosis and apoptosis. In control experiments the mitotic was higher than the apoptotic index, whilst in the presence of SF this was reversed. These results were confirmed using in situ end-labelling. SF, therefore, may stimulate apoptotic, but inhibit mitotic, activity in MG63 cells. This raises the possibility that components of SF might induce subtle changes in the balance between apoptosis and mitosis, which, in turn, could contribute to the progression of periodontitis.
Gadhavi
A
A
Department of Periodontology, Eastman Dental Institute, University College London, 256 Grays Inn Road, WC1X 8LD, London, UK.
Wilson
M
M
Tabona
P
P
Newman
H N
HN
Henderson
B
B
Bennett
J H
JH
D016976:Aggregatibacter actinomycetemcomitans / Q000502:physiology*; D017209:Apoptosis / Q000187:drug effects*; D001425:Bacterial Outer Membrane Proteins / Q000494:pharmacology*; D002448:Cell Adhesion; D002452:Cell Count; D004396:Coloring Agents; D016895:Culture Media, Serum-Free; D018450:Disease Progression; D004801:Eosine Yellowish-(YS); D005456:Fluorescent Dyes; D006416:Hematoxylin; D006801:Humans; D020287:In Situ Nick-End Labeling; D008938:Mitosis / Q000187:drug effects*; D012516:Osteosarcoma / Q000473:pathology* / Q000503:physiopathology; D010518:Periodontitis / Q000209:etiology / Q000473:pathology; D014407:Tumor Cells, Cultured
D001425:Bacterial Outer Membrane Proteins; D004396:Coloring Agents; D016895:Culture Media, Serum-Free; D005456:Fluorescent Dyes; D004801:Eosine Yellowish-(YS); D006416:Hematoxylin