Lieberman M D, Paty P, Li X K, Naama H, Evoy D, Daly J M
Department of Surgery, Cornell University Medical College-New York Hospital, NY., USA.
Surgery. 1996 Aug;120(2):354-9. doi: 10.1016/s0039-6060(96)80309-6.
The epidermal growth factor (EGF) signal transduction pathway, frequently activated in pancreatic cancer, is an important regulator of cellular growth and transformation. This study examined whether activation of the cyclic adenosine monophosphate protein kinase A pathway may inhibit the EGF signal transduction pathway in pancreatic cancer cell lines.
Human pancreatic cancer lines BxPC-3 and AsPC-1 were stimulated with EGF, forskolin, or both. Forskolin is a compound that increases cyclic adenosine monophosphate levels. Assays of cell lines were then obtained for cellular growth (MTT assay), anchorage-independent growth (soft agar), and EGF-induced mitogen-activated protein kinase activation as measured by an in-gel kinase assay.
Treatment with forskolin resulted in inhibition of EGF-induced activation of mitogen-activated protein kinase activity (BxPC-3 78% inhibition and AsPC-1 70% inhibition, p < 0.005), diminished cellular proliferation (BxPC-3 92% inhibition and AsPC-1 86% inhibition, p < 0.001), and formation of colonies in soft agar (BxPC-3 98% inhibition and AsPC-1 76% inhibition, p < 0.001). Forskolin did not inhibit EGF receptor autophosphorylation or tyrosine kinase signaling in response to EGF.
Forskolin-induced inhibition of mitogen-activated protein kinase is associated with diminished pancreatic cancer cell proliferation in vitro. Use of strategies to increase cyclic adenosine monophosphate levels may have therapeutic application in pancreatic cancer.
表皮生长因子（EGF）信号转导通路在胰腺癌中经常被激活，是细胞生长和转化的重要调节因子。本研究检测了环磷酸腺苷蛋白激酶A通路的激活是否可能抑制胰腺癌细胞系中的EGF信号转导通路。
用人胰腺癌系BxPC-3和AsPC-1分别用EGF、福斯高林或两者同时刺激。福斯高林是一种能增加环磷酸腺苷水平的化合物。然后对细胞系进行细胞生长（MTT法）、非锚定依赖性生长（软琼脂法）以及通过凝胶内激酶测定法测量的EGF诱导的丝裂原活化蛋白激酶激活的检测。
用福斯高林处理导致EGF诱导的丝裂原活化蛋白激酶活性受到抑制（BxPC-3抑制78%，AsPC-1抑制70%，p<0.005），细胞增殖减少（BxPC-3抑制92%，AsPC-1抑制86%，p<0.001），以及在软琼脂中形成集落减少（BxPC-3抑制98%，AsPC-1抑制76%，p<0.001）。福斯高林不抑制EGF受体的自身磷酸化或对EGF的酪氨酸激酶信号传导。
福斯高林诱导的丝裂原活化蛋白激酶抑制与体外胰腺癌增殖减少有关。采用提高环磷酸腺苷水平的策略可能在胰腺癌治疗中具有应用价值。
