Heat shock protein 60 is a disease-associated sialoglycoprotein in human non-small cell lung cancer.

The diagnostic and therapeutic potential of Maackia amurensis agglutinin (MAA) have been reported in various malignancies. Earlier, we have found that MAA specifically interacted with human non-small cell lung-cancer (NSCLC) cells and induced apoptosis in these cells. The present study was designed to identify Maackia amurensis leukoagglutinin (MAL-I, one of the components of MAA, having same carbohydrate specificity as MAA) interacting membrane sialoglycoprotein(s) of two subtypes of human NSCLC cell lines. Nine proteins were identified using 2D-PAGE followed by MAL-I-overlay transblotting and MALDI-TOF mass spectrometry. Among these proteins, HSP60 was selected for further characterization. Sialoglycoprotein nature of membrane-HSP60 of NSCLC cell lines was confirmed by its reduced reactivity with MAL-I in Western blots in presence of GM2 and by dual staining of the cell lines with MAL-I and HSP60-antibody. These findings were further substantiated by enzymatic analysis of membrane-HSP60 as well as in-silico evidence regarding this protein. Our observations were validated by immunohistochemical analysis of both subtypes of NSCLC tissue sections. Membrane-HSP60 was found to be involved in inhibition of MAL-I induced morphological alteration of NSCLC cells and in proliferation and migration of these cells, indicating the probable role of sialylated membrane-HSP60 in this disease.