Cell growth inhibition of tumour cell lines induced by the peptide fraction. HeLa (a) and U2OS (b) cells were treated with 1 μg/ml (white) and 2 μg/ml (black) of peptide pool for 1, 2 and 4 days. Gray bars represent untreated controls. Error bars show the standard deviation obtained from three independent experiments. Student’s test. *p < 0.05 **p < 0.01.