ABSTRACT
Alveolar epithelia play an essential role in maintaining the integrity and homeostasis of lungs, in which alveolar epithelial type II cells (AECII) are a cell type with stem cell potential for epithelial injury repair and regeneration. However, mechanisms behind the physiological and pathological roles of alveolar epithelia in human lungs remain largely unknown, partially owing to the difficulty of isolation and culture of primary human AECII cells. In the present study, we aimed to characterize alveolar epithelia generated from A549 lung adenocarcinoma cells that were cultured in an air-liquid interface (ALI) state. Morphological analysis demonstrated that A549 cells could reconstitute epithelial layers in ALI cultures as evaluated by histochemistry staining and electronic microscopy. Immunofluorescent staining further revealed an expression of alveolar epithelial type I cell (AECI) markers aquaporin-5 protein (AQP-5), and AECII cell marker surfactant protein C (SPC) in subpopulations of ALI cultured cells. Importantly, molecular analysis further revealed the expression of AQP-5, SPC, thyroid transcription factor-1, zonula occludens-1 and Mucin 5B in A549 ALI cultures as determined by both immunoblotting and quantitative RT-PCR assay. These results suggest that the ALI culture of A549 cells can partially mimic the property of alveolar epithelia, which may be a feasible and alternative model for investigating roles and mechanisms of alveolar epithelia in vitro.
Subject(s)
Humans , Culture Media, Conditioned , Cell Culture Techniques/methods , Alveolar Epithelial Cells/physiology , A549 Cells/physiology , Reference Values , Time Factors , Microscopy, Electron, Scanning , Immunoblotting , Cell Count , Reproducibility of Results , Analysis of Variance , Pulmonary Surfactant-Associated Protein C/analysis , Aquaporin 5/analysis , Mucin-5B/analysis , Real-Time Polymerase Chain Reaction , Zonula Occludens-1 Protein/analysis , Thyroid Nuclear Factor 1/analysisABSTRACT
The coexistence of multiple primary malignant tumors in the same host is not unusual; however, tumor-to-tumor metastasis is rare. According to previous publications, the most common recipient tumor is renal cell carcinoma, and lung carcinoma is the most frequent donor site. According our bibliographic search we are presenting the first published case of primary pulmonary moderately differentiated adenocarcinoma metastatic to a schwannoma, demonstrated with Thyroid Transcription Factor 1 (TTF-1); immunostaining has become an important tool for guiding diagnosis of adenocarcinoma.
La coexistencia de múltiples tumores malignos primarios en un huésped no es un evento infrecuente. Sin embargo, la presencia de una neoplasia con metástasis en otra neoplasia (metástasis de tumor a tumor) es una entidad inusual, según lo publicado en la literatura el tumor receptor más frecuente es el carcinoma de células renales y el donante el carcinoma de pulmón. En el siguiente reporte se presenta un caso de adenocarcinoma moderadamente diferenciado metastásico a schwannoma, donde por inmunomarcaje con el Factor 1 de Transcripción Tiroidea (TTF-1) se demostró el origen pulmonar de la lesión, este correspondería al primer caso según nuestra revisión bibliográfica.