Journal: Proceedings of the National Academy of Sciences of the United States of America
Article Title: 2-Sulfonylpyrimidines: Mild alkylating agents with anticancer activity toward p53-compromised cells
doi: 10.1073/pnas.1610421113
Figure Lengend Snippet: Biological effects of PK11007 on diverse cancer cell lines and one human fibroblast cell line. (A) Concentration-dependent viability reduction of WI-38 (fibroblast), NUGC-4 (p53 WT), HUH-6 (p53 WT), SJSA-1 (p53 WT), SW480 (p53 R273H/P309S), NUGC-3 (p53 Y220C), HUH-7 (p53 Y220C), and MKN1 (p53 V143A) cells after treatment with PK11007 for 24 h. The mutant p53 cells HUH-7, MKN1, and NUGC-3 were more sensitive to PK11007 treatment as indicated by strong viability reduction at low compound concentrations. Cell viability was measured in quadruplicate and normalized with the values of blank (viability = 1) and no cell (viability = 0) controls. Data are shown as mean ± SEM. (B) Incubation of the isogenic H1299 (p53−/−), H1299 (p53 H175), HCT116, and HCT116 p53−/− cancer cells with PK11007 yielded a comparable viability reduction after 24 h. (C) Cell viability of HUH-6, HUH-7, and MKN1 after p53 knockdown via siRNA. Cells were treated with PK11007 for 24 h (48 h for 15 µM PK11007 MKN1 sample). In HUH-6 and HUH-7, cell death was independent of p53, whereas it was partially dependent on p53 in MKN1 cells. (D) Western blots of NUGC-4, NUGC-3, MKN1, HUH-6, and HUH-7 cancer cells after 3 h (6 h for MKN1) treatment with PK11007. p53 target genes p21, PUMA, and MDM2 were up-regulated not only in MKN1 (p53-V143A), NUGC-3, and HUH-7 (both p53-Y220C), but also in HUH-6 and NUGC-4 (both p53 WT) cells. With increasing PK11007 concentration, the molecular weight of p53 gradually increased to ∼3 kDa for the mutant p53 cell lines (HUH-7, MKN1, and NUGC-3), suggesting hyperalkylation of unfolded/aggregated p53. The protein level of the antioxidative gene GSTP1 was higher in NUGC-4 (p53 WT) than in NUGC-3. The asterisks at the p53 target gene levels of HUH-6 and HUH-7 cells highlight the genes for which a different β-actin control was used. (E) Quantification of relative mRNA levels of p53 target genes via real-time PCR. Cells were treated with DMSO or 15 µM (MKN1, HUH-7) or 20 µM (NUGC-3, HUH-6) PK11007 for 6 h (4.5 h for HUH-7). p21 and PUMA mRNA levels were especially up-regulated in mutant p53 cells, whereas in p53 WT cells (HUH-6) no increased transcription was observed. Significance levels were calculated with the Student t test (***P < 0.001; **P < 0.01; *P < 0.05). (F) Western blots of protein levels of UPR key markers in MKN1, HUH-6, and HUH-7 cells. PK11007 treatment for 3 h (6 h for MKN1) increased levels of spliced XBP-1 and CHOP (especially in HUH-7). (G) Inhibition of cellular glutathione synthesis by buthionine sulfoximine strongly potentiated cell viability reduction by PK11007 in HUH-7, NUGC-3, and MKN1 mutant p53 cancer cells. (H) Determination of relative intracellular ROS levels via CellROX Deep Red fluorescence after incubating four cancer cell lines with 30 or 60 µM PK11007 for 2 h. PK11007 caused increase of ROS in all tested cell lines. However, at high doses, the increase of relative ROS levels was higher in HUH-7, NUGC-3, and MKN1 cells. Median fluorescence levels were determined in triplicate with error bars depicting the SE. Significance levels were calculated using a one-way ANOVA with the Bonferroni post hoc test for mean comparison (***P < 0.001; **P < 0.01; *P < 0.05).
Article Snippet: Cell line p53 status Organism Tissue type Disease ATCC/JCRB code WI-38 WT Human Lung — CCL-75 HUH-6 WT Human Liver Hepatoblastoma JCRB0401 NUGC-4 WT Human Stomach Gastric adenocarcinoma JCRB0834 SJSA-1 WT Human Fibroblast (lung) Osteosarcoma CRL-2098 HCT-116 WT Human Colon Colorectal carcinoma CCL-247 SW480 R273H-P309S Human Colon Dukes’ type B, colorectal adenocarcinoma CCL-228 HUH-7 Y220C Human Liver Hepatocellular carcinoma JCRB0403 NUGC-3 Y220C Human Stomach Gastric adenocarcinoma JCRB0822 MKN1 V143A Human Stomach Adenosquamous carcinoma JCRB0252 H1299 Null Human Lung Non–small cell lung cancer CRL-5803 Open in a separate window ATCC, American Type Culture Collection; JCRB, Japanese Collection of Research Bioresources.
Techniques: Concentration Assay, Mutagenesis, Incubation, Knockdown, Western Blot, Molecular Weight, Control, Real-time Polymerase Chain Reaction, Inhibition, Fluorescence, Comparison