Human tumor cells are selectively inhibited by colicins
Related Experiment Video
Updated: Sep 26, 2026
In vitro Organoid Culture of Primary Mouse Colon Tumors
Published on: May 17, 2013
1Department of Biology, Faculty of Medicine, Masaryk University, 66243 Brno, Czechia. jchumch@med.muni.cz
Abstract:
The activity in vitro of four types of colicins (A, E1, E3, U) against one human standard fibroblast line and against 11 human tumor-cell lines carrying defined mutations of the p53 gene was quantified by MTT (tetrazolium bromide) assay. Flow cytometry showed that the pore-forming colicins A, E1 and U affected the cell cycle of 5 of these cell lines. Colicins E3 and U did not show any distinct inhibitory effects on the cell lines, while colicins E1 and especially A inhibited the growth of all of them (with one exception concerning colicin E1). Colicin E1 inhibited the growth of the tumor lines by 17-40% and standard fibroblasts MRC5 by 11%. Colicin A exhibited a differentiated 16-56% inhibition, the growth of standard fibroblasts being inhibited by 36%. In three of the lines, colicins A and E1 increased the number of cells in the G1 phase (by 12-58%) and in apoptosis (by 7-58%). These results correlated with the data from sensitivity assays. Hence, the inhibitory effect of colicins on eukaryotic cells in cell-selective, colicin-specific and can be considered to be cytotoxic.
Insights
Colicins A and E1 show selective cytotoxic effects against human tumor cells and fibroblasts. These pore-forming proteins inhibit cell growth and induce apoptosis, demonstrating specific anti-cancer potential.
Area of Science:
- Microbiology
- Molecular Biology
- Cell Biology
Background:
- Colicins are bacteriocins with known antimicrobial properties.
- The cytotoxic potential of colicins against eukaryotic cells, particularly cancer cells, remains an area of investigation.
- Tumor cells with p53 gene mutations represent a significant challenge in cancer therapy.
Purpose of the Study:
- To quantify the in vitro activity of colicins A, E1, E3, and U against human tumor cell lines and normal fibroblasts.
- To investigate the effects of pore-forming colicins on the cell cycle and apoptosis in cancer cells.
- To determine the cell-selective and colicin-specific nature of colicin-induced cytotoxicity.
Main Methods:
- MTT (tetrazolium bromide) assay for quantifying cell activity.
- Flow cytometry for cell cycle and apoptosis analysis.
- Testing against one human standard fibroblast line and eleven human tumor-cell lines with p53 mutations.
Main Results:
- Colicins E1 and A demonstrated significant inhibition of tumor cell growth (17-56%) and fibroblast growth (11-36%).
- Pore-forming colicins A, E1, and U affected the cell cycle in 5 of the tested cell lines.
- Colicins A and E1 induced G1 phase arrest and apoptosis in specific cell lines, correlating with sensitivity data.
Conclusions:
- Colicins A and E1 exhibit potent, selective cytotoxic effects on human eukaryotic cells, including tumor lines.
- The observed inhibition of cell growth and induction of apoptosis suggest colicins can be considered cytotoxic agents.
- Colicin activity is specific to cell type and colicin type, highlighting their potential as targeted therapeutic agents.
