REVELATION AND IDENTIFICATION OF LAMININ IN THE STRUCTURE OF PLASMA MEMBRANE OF
ASCITIC ZAJDELA HEPATOMA CELLS
I. I. Tyuryaeva,1, * O. A. Mirgorodskaya,1 O. A. Cherepanova,1
E. P. Podolskaya,2
A. V. Novikov,2 M. A. Hodorkovski,3 V. A. Ivanov 1
1 Institute of Cytology RAS, 2 Institute of Analytical Instrumentation RAS, and
3 State Institute of Applied Chemistry, St. Petersburg, Russia;
* e-mail: reducer@mail.ru
Cell dysdifferentiation during neoplastic transformation is a crucial problem of cell biology and oncology. Antigenic
diversion of cancer cells is a typical characteristic of dysdifferentiation. It involves the appearance of antigens which are unusual for
normal tissue of this type. Components organospecific for membrane proteins of normal kidney were previously found among plasma membrane
proteins of hepatocellular rat tumors, rat hepatocytes after carcinogen treatment, and regenerating liver, respectively. In the present
work we showed that a protein with mol. weight about 200 kDa reacting with laminin-1 immunoserum is the basic component of plasma
membranes of the rat Zajdela hepatoma cells, which is responsive for organospecific anti-kidney immunoserum in Western blot. A
mass-spectrometer analysis of trypsin proteolysis fragments was carried out in SDS-PA-GE slices containing the investigated component.
The analysis showed the presence of β1-, β2- and α4 laminin chains peptides. The component with mol. weight about 180 kDa, found in the
Western blot with laminin-1 immunoserum, was also subjected to the mass spectrometer analysis. As a result, a γ1 laminin chain was found.
An increased amount of laminin was revealed in the ascitic liquid and sera of rat with developed Zajdela hepatoma, in comparison with
sera of normal rats. In addition, we found the appearance of laminin on the hepatocyte surface on the 4th day after hepatocarcinogen
injection (N-diethylnitrosamine, DENA). Thus, for the first time tumor associated antigens were revealed and identified in the structure
of plasma membranes of Zajdela hepatoma cells, being specific to rat kidneys. Our results allow to conclude that in the process of
carcinogenesis in rat liver laminin synthesis occurs, which is also characteristic of the rat hepatoma Zajdela cells.
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