Skip to main content
. 2013 Sep 3;8(9):e74071. doi: 10.1371/journal.pone.0074071

Figure 1. Hydrolysis of MNNG & TMZ to active cation and deficient MMR & MGMT protein expression in cancer cells results in increased colony survival after MNNG exposure.

Figure 1

A) N-methyl-N’-nitro-N-nitrosoguanidine (MNNG) and temozolomide (TMZ) hydrolytic conversion to the same methyldiazonium cation. MNNG requires fewer hydrolytic steps to produce the same highly reactive cation. B) MMR & MGMT protein expression in six cell lines by SDS PAGE and immunoblot and C) colony survival of five cell lines after MNNG treatment. MCF12A (normal mammary epithelium) expressing all four MMR proteins and MGMT are most resistant to MNNG because of MGMT expression. MCF12A +siMGMT are more sensitive because of knocked down MGMT (Figure S1). HeLa MR (cervical cancer) and U251 (glioblastoma) are most sensitive because of lack of MGMT and proficient MMR-induced DDR. HeLa MNNGR and U251 MNNGR are resistant (tolerant) due to lack of both MMR and MGMT. Each colony survival was performed a minimum of four times, with average % survival depicted. SD was less than 5% for each average.