B. subtilis can be used to deliver anti-tumour compounds. In recent work (Nguyen, et al., 2013) we showed that spores can be engineered to display a monoclonal antibody (termed Cetuximab) that recognizes a marker (EGFR; Epidermal Growth Factor Receptor) that is expressed on cancer cells. Next, we loaded the anti-cancer drug Paclitaxel onto the surface of spores and were able to specifically target cancer cells in vitro. This focused the drug on the surface of affected cells and cell growth was inhibited. This approach is now being followed in animal studies and if successful opens up numerous possibilities for targeting of drugs to a variety of cancerous cells.

Binding of paclitaxel labeled Oregon on HT29 colon cancer cells

Laser scanning confocal micrographs showing the green signal of paclitaxel Oregon Green 488 bound on HT29 cells at concentrations of 1M paclitaxel in different formulations. Negative control image without paclitaxel (panel A), water-soluble paclitaxel (panel B), paclitaxel adsorbed to 5 x 108 spores of PY79 (panel C), paclitaxel adsorbed with 5 x 10SA1 spores (panel D).