Author/Editor		Grujić, Mirjana
Title		Mehanizem delovanja bestatina in aktinonina na proliferacijo celic
Type		monografija
Place		Ljubljana
Publisher		Medicinska fakulteta
Publication year		2000
Volume		str. 57
Language		slo
Abstract		It is assumed that APN has an important role in regulation of the cell cycle because inhibitors of APN (bestatin, probestin and actinonin) inhibit cell proliferation (Ino et al., 1994; Lendeckel et al., 1996). We intended to confirm the assumption with new inhibitor of APN, anstatin. First we have measured the influence of four aminopeptidase inhibitors (actinonin, bestatin, amastatin and anstatin) on cell proliferation, using two human cancer cell lines, myeloic macrophages (U937) and undifferentiated granulocyts (K562). Bestatin and actinonin inhibited cell proliferation but anstatin, which is the most specific inhibitor of APN, did not. From this we concluded that inhibition of activity of APN on the cell surface is not sufficient for inhibition of cell proliferation. To confirm this assumption and to find the AP, whose inhibition by bestatin or actinonin leads to suppressed cell growth, we determined the IC50 of the aminopeptidase inhibitors against the following AP activities on the cell surface: APN, LAP, APB and DPP-IV. Further, we compared these IC50 values with IC50 values for inhibition of cell proliferation and concluded that actinonin does not exert its growth suppressive effect through inhibition of any AP tested, but that bestatin may act by inhibiting APB. We attempted to isolate APB by affinity chromatography. We applied cytoplasmic proteins and proteins from the nucleus to bestatin sepharose and anstatin sepharose. SDS PAGE showed no difference between the proteins (from cytoplasm or nucleus) eluted from bestatin sepharose and anstatin sepharose. We also showed, using the dye trypan blue, that bestatin and actinonin do not exhibit cytotoxic effects.
Descriptors		CELL DIVISION CELL CYCLE PROTEINS TUMOR CELLS, CULTURED AMINOPEPTIDASES