Rydell E L, Axelsson K L, Olofsson J, Hellem S
Department of Pharmacology, Faculty of Health Sciences, Linköping, Sweden.
Cancer Biochem Biophys. 1990 Jul;11(3):187-94.
In the present study the activities of three different protein kinase were determined in squamous cell carcinoma from the upper aero-digestive tract, and compared with the activities in normal oral mucosa. The protein kinases investigated are: a) cAMP-dependent protein kinase; b) cGMP-dependent protein kinase, and c) casein kinase II. The basal protein kinase activity, when histone IIa was used as substrate, was about 3-fold higher in tumors, as compared to normal mucosa, in the soluble fraction (32.0 +/- 4.2 and 10.9 +/- 2.4 pmol 32P/mg prot. X min, respectively). In the particulate fraction the basal protein kinase activity was about 9 times higher in tumors as compared to normal mucosa (19.4 +/- 5.2 and 2.1 +/- 0.3 pmol 32P/mg prot X min, respectively). The protein kinase activity in the presence of cyclic nucleotide (cAMP/cGMP) minus the basal protein kinase activity was taken as the cAMP- and the cGMP-dependent protein kinase activity, respectively. Maximal protein kinase activity was obtained in the presence of 0.5 microM of cyclic nucleotide both in squamous cell carcinoma and normal mucosa. In the cytosolic fraction the cAMP-dependent protein kinase activity was 33.9 +/- 13.0 pmol 32P/mg prot. X min in tumors, and 28.2 +/- 5.8 pmol 32P/mg prot. X min in normal tissue, after stimulation with 0.5 microM cAMP. The cGMP-dependent protein kinase activity was 5-10% of the cAMP-dependent protein kinase activity, and no concentration-dependent stimulation with cGMP was seen. The cGMP-dependent protein kinase activity in the presence of 0.5 microM cGMP was 2.4 +/- 1.3 and 1.8 +/- 0.6 pmol 32P/mg prot. X min in tumors and normal mucosa, respectively. Casein kinase II activity was determined only in the cytosolic fraction and was found to be 3-fold higher in tumors as compared to normal mucosa (31.8 +/- 5.2 and 8.6 +/- 3.5 pmol 32P/mg prot X min, respectively). This study shows a general increase in histone phosphorylation and casein kinase activity in neoplastic squamous epithelia compared to normal epithelia. No evidence for an increase in cyclic nucleotide dependent protein kinase activities in neoplastic squamous epithelia was found. This study thus supports the idea that phosphorylation/dephosphorylation reactions may play an important role in the control of cell growth, differentiation and proliferation.
在本研究中，测定了上呼吸消化道鳞状细胞癌中三种不同蛋白激酶的活性，并与正常口腔黏膜中的活性进行了比较。所研究的蛋白激酶有：a）环磷酸腺苷（cAMP）依赖性蛋白激酶；b）环磷酸鸟苷（cGMP）依赖性蛋白激酶；c）酪蛋白激酶II。以组蛋白IIa为底物时，肿瘤组织可溶性部分的基础蛋白激酶活性比正常黏膜高约3倍（分别为32.0±4.2和10.9±2.4 pmol 32P/mg蛋白·分钟）。在颗粒部分，肿瘤组织的基础蛋白激酶活性比正常黏膜高约9倍（分别为19.4±5.2和2.1±0.3 pmol 32P/mg蛋白·分钟）。环核苷酸（cAMP/cGMP）存在时的蛋白激酶活性减去基础蛋白激酶活性，分别作为cAMP依赖性和cGMP依赖性蛋白激酶活性。在鳞状细胞癌和正常黏膜中，在0.5微摩尔环核苷酸存在时均获得最大蛋白激酶活性。在胞质部分，用0.5微摩尔cAMP刺激后，肿瘤组织中cAMP依赖性蛋白激酶活性为33.9±13.0 pmol 32P/mg蛋白·分钟，正常组织中为28.2±5.8 pmol 32P/mg蛋白·分钟。cGMP依赖性蛋白激酶活性为cAMP依赖性蛋白激酶活性的5 - 10%，未观察到cGMP的浓度依赖性刺激。在0.5微摩尔cGMP存在时，肿瘤组织和正常黏膜中cGMP依赖性蛋白激酶活性分别为2.4±1.3和1.8±0.6 pmol 32P/mg蛋白·分钟。仅在胞质部分测定了酪蛋白激酶II的活性，发现肿瘤组织中的活性比正常黏膜高3倍（分别为31.8±5.2和8.6±3.5 pmol 32P/mg蛋白·分钟）。本研究表明，与正常上皮相比，肿瘤性鳞状上皮中的组蛋白磷酸化和酪蛋白激酶活性普遍增加。未发现肿瘤性鳞状上皮中环核苷酸依赖性蛋白激酶活性增加的证据。因此，本研究支持磷酸化/去磷酸化反应可能在细胞生长、分化和增殖的控制中起重要作用这一观点。
