Expression of Q227L-Gαs in MCF-7 human breast cancer cells inhibits tumorigenesis
Expression of Q227L-Gαs in MCF-7 human breast cancer cells inhibits tumorigenesis
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DOI：
10.1073/pnas.95.5.2648
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发表时间：
1998-03-03
影响因子：
11.1
通讯作者：
Iyengar, R
中科院分区：
文献类型：
--
作者：
Chen, JH;Bander, JA;Iyengar, R
在MCF-7人乳腺上皮细胞系中，研究了突变体（Q227L）激活的G α (s)的表达和cAMP的升高对丝裂原激活蛋白激酶（MAPK）活性和转化表型的影响。cAMP的升高部分抑制了表皮生长因子刺激的DNA合成和血清饥饿MCF-7细胞的内在MAPK （ERK-1和ERK-2）。在MCF-7细胞中添加8Br-cAMP或表达突变体（Q227L）激活的G α (s)阻断了这些细胞以不依赖锚定方式生长的能力，通过软琼脂集落形成评估，培养基中的8Br-cAMP也阻断了雌激素对MCF-7细胞体外增殖的刺激，表达Q227L-G α (s)的MCF-7细胞在体外生长非常缓慢，当将这些细胞注射到植入雌激素颗粒的胸腺小鼠体内时，与转染空载体的MCF-7细胞相比，转染后的MCF-7细胞形成肿瘤的频率大大降低，形成的肿瘤大小也小得多。这些结果表明，转化后的乳腺上皮细胞细胞内cAMP的水平可能是决定转化表型表达的关键因素。G(s)/腺苷酸环化酶与mapk -1,2信号通路之间的相互作用可能是调节乳腺上皮细胞转化表型表达的一种机制。
The effects of expression of mutant (Q227L)-activated G alpha(s) and elevation of cAMP on mitogen-activating protein kinase (MAPK) activity and the transformed phenotype were studied in the MCF-7 human mammary epithelial cell line, Elevation of cAMP partially inhibited the epidermal growth factor-stimulated DNA synthesis and the intrinsic MAPK (ERK-1 and ERK-2) of serum-starved MCF-7 cells, Addition of 8Br-cAMP or expression of mutant (Q227L)-activated G alpha(s) in MCF-7 cells blocked the ability of these cells to grow in an anchorage-independent manner, as assessed by colony formation in soft agar, 8Br-cAMP in the culture medium also blocked estrogen stimulation of MCF-7 cell proliferation in vitro, MCF-7 cells expressing Q227L-G alpha(s) grew very slowly in vitro, and when these cells were injected s.c. into athymic mice implanted with estrogen pellets, the frequency of tumor formation was reduced greatly and the sizes of the tumors formed were much smaller than those in mice injected with MCF-7 cells that had been transfected with the empty vector, These results indicate that the intracellular levels of cAMP in transformed mammary epithelial cells can be a crucial factor in determining the expression of the transformed phenotype, Interactions between the G(s)/adenylyl cyclase and MAPK-1,2 signaling pathways could be one mechanism by which expression of the transformed phenotype in mammary epithelial cells are regulated.