EXPRESSION OF NEURON-SPECIFIC ENOLASE, CHROMOGRANIN-A, SYNAPTOPHYSIN AND LEU-7 IN LUNG-CANCER CELL-LINES

Recent reports indicate that Small Cell Lung Cancer (SCLC) responds fa vorably to chemotherapy, and this response is associated with the expr ession of neuroendocrine (NE) markers. However, the currently availabl e reports on the expression of NE markers in SCLC and Non-Small Cell L ung Cancer (NSCLC) are highly inconsistent and need to be reevaluated. Therefore, we have undertaken the current study to clearly define the expression of NE markers in SCLC and NSCLC using representative cell lines. We studied the NE markers, chromogranin A, Neuron specific enol ase (NSE), Leu-7 and synaptophysin using various immunochemical and mo lecular biological methods. By employing Western blotting method, we f ound that both SCLC and NSCLC cells express large amounts of NSE and c hromogranin A. The natural killer cell surface associated antigen (Leu -7) was expressed specifically only by SCLC cell lines. This finding w as further confirmed by immunofluorescence staining of the SCLC cells. We could not detect any synaptophysin levels in any of the above cell types by Western blotting technique. Therefore, we employed reverse t ranscription polymerase chain reaction (RT.PCR) to study the expressio n of synaptophysin mRNA and found that both SCLC and NSCLC cells expre ss it, albeit in different amounts.