Figure 5. MnTnBuOE-2-PyP does not protect colorectal cancer cells from common therapeutic regimens used clinically for colorectal and anal cancers.

The effect of MnTnBuOE-2-PyP (BuOE) on dose response to x-radiation or chemotherapy or combinations of those therapies was determined by clonogenic survival. A. HT-29 cells growing in log phase were treated overnight with 0.5 μM BuOE then treated with [0, 0.5, 1, 2, 4, 6 Gy] x-rays. The surviving fraction was significantly reduced (p<0.0001) in BuOE treated cells, however the dose response due solely to radiation was not enhanced or diminished by the addition of BuOE (DMF=0, A-inset). B. HT-29 cells growing in log phase were treated overnight with 0.5 μM BuOE then treated with [0, 2.5, 5, 10 μM] 5-fluorouracil for 24 hours. The surviving fraction was significantly reduced (p=0.0005) in BuOE treated cells, additionally the dose response due solely to 5-fluorouracil was enhanced by the addition of BuOE (DMF=1.3 ± 0.06, B-inset). C. HT-29 cells growing in log phase were treated overnight with 0.5 μM BuOE then treated with [0, 1, 2, 3 μM] Mitomycin for 2 hour. The surviving fraction was significantly reduced (p<0.0001) in BuOE treated cells, the dose response due solely to Mitomycin was enhanced by the addition of BuOE (DMF=1.7 ± 0.13, C-inset). D. HT-29 cells were exposed overnight to 0.5 μM BuOE or PBS, cells were then treated with 1.5 μM 5-fluorouracil for 24 hours. Half of those cells were treated with 0.5 μM Mitomycin during the final hour of 5-fluorouracil incubation. All of the samples were irradiated with 1 Gy x-rays and then seeded for clonogenic survival. The combination of 5-fluorouracil and radiation was significantly enhanced in the presence of BuOE (p=0.004) and likewise the combination of 5-fluorouracil, Mitomycin, and radiation was significantly enhanced (p=0.006) by BuOE treatment. All data are representative of the mean and standard deviation and were obtained from 3 independent experiments.