Pineal peptide with an inhibiting effect on growth of HeLa S3 tumor cells.

The aim of the present study was to assess whether a peptide fraction isolated from calf pineal glands has an effect on proliferation and morphology of HeLa S3 tumor cells. Under the experimental conditions adopted, the results showed that the peptide has a marked inhibitory effect on proliferation of HeLa S3 cells and that permeabilization with calcium phosphate of the plasmatic membrane increases this effect. Moreover, the pineal peptide affects the cytoskeletal morphology of HeLa cells by modifying the distribution of actin. The peptide is probably internalized by the cells and irreversibly modifies the cytoskeletal morphology with consequent inhibition of cellular proliferation.