Figure 3 Zn-curc induces a wild-type-like conformational change in mutant p53 proteins. (A) Immunofluorescence of SKBR3 (H175) and U373 (H273) cells using p53-conformation-specific JPH203 datasheet antibodies (PAB1620 for wt, folded conformation and PAB240 for mutant, unfolded conformation). Cells were treated with Zn-curc (100 μM) for 24 h before fixing and staining with antibodies. The RKO (wtp53) cell line is used as a control to show that the wtp53 conformation is not changed by Zn-curc treatment. Quantification of SKBR3 (B) or RKO (C) positive cells to PAB1620 and PAB240 antibodies before and after Zn-curc
treatment, ±SD. (D) SKBR3 and U373 cells were treated with Zn-curc (100 μM) for 24 h. Total cell extracts were imunoprecipitated (IP) with conformation-specific antibodies (PAB1620 and PAB240) and then imunoblotted (WB) with anti-p53 (DO1) antibody. Input represents
1/10 of total cell extracts used for IP. Zinc-curc localizes in glioblastoma tissues of an orthotopic mice model Targeting a tumor tissue with a systemically administrated anticancer drug is of great importance especially for those tumors difficult to reach such as brain tumor where the blood-tumor barrier (BTB) plays a negative role. Therefore, we took advantage of the fluorescent feature of the Zn-curc compound [13, 14] to evaluate its intratumoral localization. To this aim we used human U373 glioblastoma cells engineered with luciferase reporter (U373-LUC) for imaging VRT752271 in vivo analysis . U373-LUC cells were injected into the brain of athymic nude mice. Ortothopic tumors were let to growth for 6 days, as evaluated by imaging analysis (data not shown), before treating animals with Zn-curc
(10 mg/Kg) every day for 7 days. Glioblastoma untreated or treated tissues were then harvested and analysed with a fluorescent microscope that revealed a diffuse fluorescence into the glioblastoma tissues treated with Zn-curc, compared to the see more Mock-treated tumors (Figure 4A), as also evidenced by quantification of the fluorescence positive cells (Figure 4B). In addition, RT-PCR analyses of the U373-derived tumors showed reactivation of the wtp53 target genes (Puma and Noxa) only after Zn-curc treatment to detriment of mutant p53 target gene MDR1 (Figure 4C); moreover, VEGF and Bcl2 mRNA levels were markedly downregulated in the Zn-curc-treated tumors Tyrosine-protein kinase BLK (Figure 4C). These findings indicate that Zn-curc complex can reach the intratumoral localization and modify molecular pathways for antitumor purpose. Figure 4 Zn-curc reactivates mtp53 in an orthotopic U373 glioblastoma model. (A) U373MG-LUC cells (2.5×105) were injected into the brain of athymic mice and left to growth for 6 days before treating animals with Zn-curc every day for 7 days. Mock- or Zn-curc-treated U373M-derived tumors were then harvested and analysed with a fluorescent microscope that showed as diffuse fluorescence only in Zn-curc-treated tumors.