[Analysis of swelling stress and signaling pathway of human lung cancer cells].

Objective To investigate whether swelling stress exists in lung cancer cells by comparing water content and nucleus size as well as mitogen activated protein kinase (MAPK) phosphorylation activation between lung cancer tissues and corresponding paracancerous tissues. Methods Differences in water content between fresh specimens of 10 human lung adenocarcinoma, 12 lung squamous cell carcinoma, and corresponding paracancerous normal lung tissues were examined through "dry and wet" mass comparison. The expressions and phosphorylation activation of mitogen activated protein kinases JNK, ERK1/2, and p38 in 30 lung adenocarcinoma samples, 32 lung squamous cell carcinoma samples, and alveolar epithelial cells and lung bronchial epithelial cells of 10 paracancerous normal tissues samples were detected with their phosphorylated and non-phosphorylated antibodies and by immunohistochemical staining. Nucleus size differences between cancer cells from lung adenocarcinoma and lung squamous cell carcinoma samples and corresponding paracancerous normal lung alveolar epithelial cells or bronchial epithelial cells were estimated by HE staining and analyzed with image analysis software. Results The average water content of lung squamous cell carcinoma and lung adenocarcinoma samples were significantly higher than that of their corresponding paracancerous normal tissues. Immunohistochemistry showed that p38 was highly expressed in all samples of lung adenocarcinoma, lung squamous cell carcinoma, and paracancerous tissues. ERK was weakly expressed in lung adenocarcinoma and squamous cell carcinoma samples, but highly expressed in paracancerous tissues. JNK was weakly expressed in lung adenocarcinoma and paracancerous tissues. JNK, p38 MAPK, and ERK1/2 were not activated through phosphorylation in alveolar or bronchial epithelial tissues. However, JNK, not p38 or ERK1/2, was phosphorylated in lung adenocarcinoma and lung squamous cell carcinoma tissues. The average nucleus size of lung cancer cells was significantly larger than those of their corresponding paracancerous normal lung epithelial cells. Conclusion There is swelling stress in lung cancer cells, and different types of human lung cancer cells have different swelling stress signaling pathways.