STAT3 and ras-MAPK signal transduction pathway in non-small cell lung cancer

Abstract

Biochemical and genetic researches suggest that ras protein plays an important role in transduction process of cell proliferation differentiation signals from activated transmembrane receptors to substream protein kinases. This study is to explore the expression of ras, p38, both of which are members of MAPK (mitogen activated protein kinases) signal transduction pathway, and STAT3 (signal transducer and activator of transcription 3) in non-small cell lung cancer, and the association among them. Forty-two resected lung cancer and paracancerous lung tissue samples were used to determine the protein expression of ras, p38 and STAT3 with Western blot, the mRNA expression of p38 and STAT3 in lung cancer tissues of various ras protein expression with RT-PCR. The location of p38 and STAT3 in lung cancer tissues was revealed with immunofluorescent staining. The relative protein expressions of ras, p38 and STAT3 were 0.6012, 0.6724, 0.5119 in cancer tissues, and 0.2793, 0.3071, 0.1917 in paracancerous lung tissues, respectively (P < 0.01). The protein and mRNA expressions of p38 and STAT3 ( 0.7624 and 0.6262; 1.0309 and 1.0538) in cancer tissues with higher ras protein expression were remarkably higher than those with lower ras protein expression (0.4715 and 0.2569; 0. 6569 and 0.3437, P < 0.01). There was a significant correlation between the expression of ras, p38 and STAT3 (correlation coefficient: 0.809 and 0.842, P < 0.01), and so was the p38 and STAT3 (correlation coefficient: 0.829, P < 0.01). Abnormal expressions of STAT3 and some factors of ras-MAPK signal transduction pathway exist in the oncogenesis and development of non-small cell lung cancer, and many of them may have crosstalk.