分化诱导剂对人肝癌细胞亚细胞组分酪氨酸蛋白激酶的早期影响

Early Effects of Diffrentiation Inducers on Tyrosine Protein Kinase in Subcellular Fractions of Human Hepatocarcinoma Cell Line

研究双丁酰环磷酸腺苷（ｄｂｃＡＭＰ）和全反式维甲酸（ＡＴＲＡ）两种分化诱导剂对人肝癌细胞株ＳＭＭＣ－７７２１亚细胞组分中酪氨酸蛋白激酶（ＴＰＫ）的早期（２４ｈ内）效应。方法用超离心等法制备胞液（ｃ），胞核（ｎ）和膜性（ｍ）ＴＰＫ酶液，以聚谷氨酸∶酪氨酸（ｐｏ１ｙＥ．Ｙ）４∶ｌ及γ－３２Ｐ－ＡＴＰ为底物测定ＴＰＫ活力。结果对照和ｄｂｃＡＭＰ处理１ｈ使ｃＴＰＫ和ｎＴＰＫ升高，以后对照降至原有水平，而ｄｂｃＡＭＰ处理细胞的ｎＴＰＫ在１２～２４ｈ略低于对照细胞，但ｍＴＰＫ在１ｈ反而降低，在３ｈ（对照）或６ｈ（ｄｂｃＡＭＰ）升至高峰，１２ｈ后ｄｂｃＡＭＰ使ｍＴＰＫ活力低于对照。ＡＴＲＡ作用于ＳＭＭＣ－７７２１细胞后，１ｈ可使三类ＴＰＫ活力均升至高峰，１２ｈ后ｃＴＰＫ和ｎＴＰＫ活力低于对照细胞，但ｍＴＰＫ活力在２４ｈ才低于对照。结论ｄｂｃＡＭＰ和ＡＴＲＡ对不同亚细胞组分ＴＰＫ有不同的时相效应。一般说来，早期（１～６ｈ）有升高作用，而在１２～２４ｈ则有一下降作用。

Purpose To study the early effect ( within 24h ) of two differentiation inducers, all trans retinoic acid (ATRA) and dibutyryl cyclic adenosine monophosphte( db cAMP ), on tyrosine protein kinase ( TPK ) in the subcellular fractions of human hepatocarcinoma cell line 7721. Methods Cytosolic (c ) , nuclear (n ) and membranous (m ) TPK enzyme preparation were prepared by ultracentrifugation and the TPK activity was assayed using polyGlu. Tyr ( 4∶l ) and γ 32 PATP as substrates. Results In the control and db cAMP treated cells, c TPK and n TPK showed activity peaks at 1h, then declined to nearly (0h) original level. At 12～24h n TPK was slightly lower in the db cAMP treated cells than in the control cells, whereas, mTPK value was decreased to the lowest at l h, and increased to peak at 3h (control) or 6h (db cAMP). The m TPK activity was lower in the dbcAMP treated cells than that in the control cells after 12h. In ATRA treated cells, 3 TPKs were all increased to their peaks value at l h, and the levels of c TPK, n TPK and m TPK were lower than the level in the control cells at 12h and 24h respectively. Conclusions The effects of db cAMP and ATRA on different TPKs in subcellular fractions were different at various time phases. Generally speaking, TPKs showed dual phasic changes, which were elevated at early stage ( l～ 6 h ) and declined at 12～24h.