Identification of CCA+ and SP-C+ cells by dual immunofluorescent labeling technique in lung tissues / 肿瘤

ABSTRACT

Objective: To determine whether there exist the cells expressing both Clara cell antigen (CCA) and surfactant protein C (SP-C) in different lung tissues from mouse, rat, and human by dual immunofluorescent labeling technique. The CCA+ and SP-C+ cells were named as the double positive cells (DPCs) which may provide the basis for further investigation of lung stem cells. Methods: The normal lung tissues were isolated from adult and newborn mice and rats. The human lung squamous carcinoma and adenocarcinoma tissues and para-cancerous lung tissues were isolated and subjected to cryosection and dual immunofluorescent staining. The DPCs in different lung tissues were identified by using laser confocal microscopy. For each specimen, four to six visual fields were selected and totally 100-200 cells were counted to calculate the percentage of DPCs. The data were analyzed by the SPSS 11.0 software. Results: The DPCs were found in normal lung tissues from adult and newborn mice and rats. DPCs were first discovered in human lung adenocarcinoma tissues but not found in lung squamous carcinoma tissues. Furthermore, the number of DPCs in the paracancerous tissues was significantly increased than the corresponding lung cancer tissues (P < 0.05). Conclusion: We not only validate the wide distribution of DPCs in the normal lung tissues, but also discover the existence of DPCs in the lung adenocarcinoma tissues and the number of DPCs in para-cancerous tissues is significantly higher than that in lung cancer tissues. Our study provide the experimental basis for further isolation and identification of DPCs and investigation of the biological features of normal lung stem cells and lung cancer stem cells.