Inhibitory effects of Notch1 overexpression on proliferation and neuroendocrine marker expression in a small cell lung cancer cell line / 中华肿瘤杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the effects of Notch1 signal activation on proliferation and neuroendocrine marker expression in small cell lung cancer cells.</p><p><b>METHODS</b>The active form of Notch1 (NIC) was over-expressed in NCI-H446 cells by constitutive transfection and a stable transfected cell line was established. Proliferation of NCI-H446 cells was analysed by MTT assay on 6 successive days. Expression of neuroendocrine markers (CgA, NSE) was observed by immunohistochemistry and Western blot analysis. Statistical analysis was conducted to compare the results in cells with NIC transfected and those in control groups.</p><p><b>RESULTS</b>MTT assay showed that absorbance (A) of cells overexpressing Notch1 was significantly depressed compared with that of the control cells (P<0.05). Immunohistochemistry of CgA showed that PUs in the NIC transfected group, sham group and negative control group were 8.81 +/- 0.77, 38.10 +/- 1.55, 38.97 +/- 0.80, respectively, the former one was significantly smaller than that of the latter two (P<0.01). Immunohistochemistry of NSE showed that PUs in the NIC transfected group, sham group and negative control group were 7.21 +/- 0.59, 28.25 +/- 1.46, 30.57 +/- 1.31, respectively, the former one was significantly smaller than that in the latter two (P<0.01). Western blot analysis showed that the gray scales of CgA in the NIC transfected group and sham group were 0.54 +/- 0.03 and 0.99 +/- 0.05, respectively, (gray scale of the negative control set as 1.00), the former one was significantly smaller than that of the other two groups (P<0.01). The gray scales of NSE in the NIC transfected group and sham group were 0.43 +/- 0.02 and 1.07 +/- 0.09, respectively (gray scale of the negative control set as 1.00), the former one was significantly smaller than that of the other two groups (P<0.01).</p><p><b>CONCLUSION</b>Notch1 may behave as a tumor suppressor in small cell lung cancer. Notch1 signal activation can inhibit the proliferation and neuroendocrine marker expression in small cell lung cancer cells, suggesting that Notch1 gene could be a new target for small cell lung cancer treatment and probable relief of paraneoplastic syndrome.</p>