Järvinen M, Ylänne J, Virtanen I
Department of Anatomy, University of Helsinki, Finland.
Cell Biol Int. 1993 Apr;17(4):399-407. doi: 10.1006/cbir.1993.1078.
We studied the effects of differentiation-inducers on the integrin profile and adhesive properties of K562 leukemia cells. The fibronectin (Fn) receptor integrin, alpha 5 beta 1, was the only integrin expressed in suspension cultured K562 cells. When the cells were exposed to 12-0-tetradecanoylphorbol-13-acetate (TPA) immunoreactivity for the beta 1 integrin subunit was slightly enhanced. TPA exposure also induced the appearance of the alpha 2, alpha 3, alpha v and beta 3 integrin subunits, but the platelet integrin subunit alpha IIb was not detected. On the other hand, hemin chloride-induced erythroid differentiation of K562 cells diminished the expression of the alpha 5 beta 1 integrin on the surface of the cells. Adhesion experiments with TPA-exposed K562 cells indicated that although the adherence to the extracellular matrix (ECM) proteins as a rule was low a few cells spread on these proteins. The present results specify the effects of differentiation inducers on the integrin profile of K562 cells and excludes the comprehension that TPA would induce expression of the platelet integrin alpha IIb on their surface. Our results also show, that an increased expression of a certain integrin does not necessarily lead to a comparable adhesion ability on its ligand in vitro.
我们研究了分化诱导剂对K562白血病细胞整合素谱及黏附特性的影响。纤连蛋白（Fn）受体整合素α5β1是悬浮培养的K562细胞中唯一表达的整合素。当细胞暴露于12 - O - 十四烷酰佛波醇 - 13 - 乙酸酯（TPA）时，β1整合素亚基的免疫反应性略有增强。TPA处理还诱导了α2、α3、αv和β3整合素亚基的出现，但未检测到血小板整合素亚基αIIb。另一方面，氯化血红素诱导的K562细胞红系分化减少了细胞表面α5β1整合素的表达。对经TPA处理的K562细胞进行的黏附实验表明，尽管通常对细胞外基质（ECM）蛋白的黏附率较低，但仍有少数细胞能在这些蛋白上铺展。目前的结果明确了分化诱导剂对K562细胞整合素谱的影响，并排除了TPA会诱导其表面血小板整合素αIIb表达的观点。我们的结果还表明，某种整合素表达的增加在体外不一定会导致对其配体具有相当的黏附能力。
