Naturally occurring and artificially induced tumor-like formations in marine invertebrates: A search for permanent cell lines

Abstract

Many problems of modern virology, biotechnology and ecology cannot be approached without the use of permanent cell lines from marine invertebrates. Tissues with high growth potential are useful for establishment of such cell lines. We estimated the prevalence of naturally occurring tumor-like lesions and neoplasms in bivalve molluscs from the Sea of Japan with the focus on cell mitotic activity and tried to induce similar formations in sea urchins in the laboratory. Inspecting nearly 3000 bivalves of eight species, we have detected the tumor-like lesions occurring in 0–15% of the total number of molluscs that were studied. Many of the molluscan tumor-like lesions had a low mitotic index (MI, 0.01–0.3%). Neoplasms with the MI 3–12% were met only in Mytilus and Pecten. Besides a search for naturally occurring tumor-like lesions and neoplasms in molluscs, we used modulation of gene expression by genetically engineered constructs bearing foreign genes, the yeast transcriptional activator gal4 gene or the agrobacterial rol oncogenes, in sea urchin embryos and sea urchin embryonic cells. We failed to develop a potential permanent cell line; however, the results obtained allow us to assert that some tumor-like formations can be useful objects for establishment of permanent cell lines. Only cells of malignant mussel hemocytes and developmental anomalies in sea urchin embryos transformed by the yeast gal4 gene were involved in active proliferation. Our findings suggest that the transformed by the yeast gal4 gene embryonic cells of sea urchins may be as a suitable model for future studies.