A Unique Cell-Surface Protein Phenotype Distinguishes Human Small-Cell from Non-Small-Cell Lung Cancer

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 79; no. 15; pp. 4650 - 4654
• Main Authors: Baylin, Stephen B., Gazdar, Adi F., Minna, John D., Bernal, Samuel D., Shaper, Joel H.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 01.08.1982; National Acad Sciences
• Subjects: Carcinoma, Small Cell - analysis; Carcinoma, Small Cell - pathology; Cell Differentiation; Cell Line; Cell lines; Endocrine cells; HeLa cells; Humans; Isoelectric Point; Lung neoplasms; Lung Neoplasms - analysis; Lung Neoplasms - pathology; Lungs; Membrane proteins; Membrane Proteins - analysis; Molecular Weight; Neoplasm Proteins - analysis; Neuroblastoma; Neuroblastoma - analysis; Neurons; Phenotypes; Squamous cell carcinoma
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.79.15.4650

We have used radioiodination (125I) and two-dimensional polyacrylamide gel electrophoresis to determine that small- (oat) cell lung carcinoma (SCC)--a tumor with neuroendocrine features--possesses a surface protein pattern distinct from the other types of lung cancer cells (squamous, adeno-, and large-cell undifferentiated carcinoma). Twelve distinguishing proteins, 40 to 70 kilodaltons (kDal), characterized four separate lines of SCC; three of these, designated E (60 kDal; pI = 7.3), S (30 kDal; pI = 6.0), and U (57 kDal; pI = 5.6), may be unique SCC gene products and were identified only in [35S]methionine labeling of SCC and not in non-SCC or human fibroblasts. Two lines of adeno-, one of squamous, and one of undifferentiated large-cell lung carcinoma exhibited similar surface protein patterns to one another. Nine distinguishing proteins (40 to 100 kDal) and at least five large proteins (>100 kDal) were unique to these lines. The surface protein phenotypes for SCC and non-SCC were distinct from those for human lymphoblastoid cells and fibroblasts. However, the neuroendocrine features of SCC were further substantiated because 6 of the 12 distinguishing SCC surface proteins, including E and U, were identified on human neuroblastoma cells. The proteins identified should (i) help define differentiation steps for normal and neoplastic bronchial epithelial cells, (ii) prove useful in better classifying lung cancers, and (iii) be instrumental in tracing formation of neuroendocrine cells.