title: Depletion of pro-oncogenic RUNX2 enhances gemcitabine (GEM) sensitivity of p53-mutated pancreatic cancer Panc-1 cells through the induction of pro-apoptotic TAp63.
abstract: Recently, we have described that siRNA-mediated silencing of runt-related transcription factor 2 (RUNX2) improves anti-cancer drug gemcitabine (GEM) sensitivity of p53-deficient human pancreatic cancer AsPC-1 cells through the augmentation of p53 family TAp63-dependent cell death pathway. In this manuscript, we have extended our study to p53-mutated human pancreatic cancer Panc-1 cells. According to our present results, knockdown of mutant p53 alone had a marginal effect on GEM-mediated cell death of Panc-1 cells. We then sought to deplete RUNX2 using siRNA in Panc-1 cells and examined its effect on GEM sensitivity. Under our experimental conditions, RUNX2 knockdown caused a significant enhancement of GEM sensitivity of Panc-1 cells. Notably, GEM-mediated induction of TAp63 but not of TAp73 was further stimulated in RUNX2-depleted Panc-1 cells, indicating that, like AsPC-1 cells, TAp63 might play a pivotal role in the regulation of GEM sensitivity of Panc-1 cells. Consistent with this notion, forced expression of TAp63α in Panc-1 cells promoted cell cycle arrest and/or cell death, and massively increased luciferase activities driven by TAp63-target gene promoters such as p21WAF1 and NOXA. In addition, immunoprecipitation experiments indicated that RUNX2 forms a complex with TAp63 in Panc-1 cells. Taken together, our current observations strongly suggest that depletion of RUNX2 enhances the cytotoxic effect of GEM on p53-mutated Panc-1 cells through the stimulation of TAp63-dependent cell death pathway even in the presence of a large amount of pro-oncogenic mutant p53, and might provide an attractive strategy to treat pancreatic cancer patients with p53 mutations.
authors.affiliation: Laboratory of DNA Damage Signaling, Chiba Cancer Center Research Institute, Chiba, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Ozaki
authors.affiliation: Laboratory of DNA Damage Signaling, Chiba Cancer Center Research Institute, Chiba, Japan.
authors.forename: Mizuyo
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Laboratory of DNA Damage Signaling, Chiba Cancer Center Research Institute, Chiba, Japan.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Ogata
authors.affiliation: Laboratory of DNA Damage Signaling, Chiba Cancer Center Research Institute, Chiba, Japan.|Department of Regenerative Medicine, Graduate School of Medicine and Pharmatheutical Science, University of Toyama, Toyama, Japan.
authors.forename: Meijie
authors.initials: M
authors.lastname: Sang
authors.affiliation: Laboratory of Cancer Genetics, Chiba Cancer Center Research Institute, Chiba, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yoda
authors.affiliation: Laboratory of Cancer Genetics, Chiba Cancer Center Research Institute, Chiba, Japan.
authors.forename: Kiriko
authors.initials: K
authors.lastname: Hiraoka
authors.affiliation: Laboratory of DNA Damage Signaling, Chiba Cancer Center Research Institute, Chiba, Japan.|Research Center, Fourth Hospital of Hebei Medical University, Shijiazhuang, China.
authors.forename: Meixiang
authors.initials: M
authors.lastname: Sang
authors.affiliation: Laboratory of DNA Damage Signaling, Chiba Cancer Center Research Institute, Chiba, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Shimozato
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D059447:Cell Cycle Checkpoints; D045744:Cell Line, Tumor; D050659:Core Binding Factor Alpha 1 Subunit / Q000502:physiology*; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D016158:Genes, p53; D006801:Humans; D008565:Membrane Proteins / Q000502:physiology*; D009154:Mutation; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D000093542:Gemcitabine
chemical_list: D000964:Antimetabolites, Antineoplastic; C081876:CKAP4 protein, human; D050659:Core Binding Factor Alpha 1 Subunit; D008565:Membrane Proteins; C493709:RUNX2 protein, human; D003841:Deoxycytidine; D000093542:Gemcitabine
keywords: RUNX2; TAp63; gemcitabine; mutant p53; pancreatic cancer