title: Intravesical instillation of c-MYC inhibitor KSI-3716 suppresses orthotopic bladder tumor growth.
abstract: OBJECTIVE
  c-MYC is a promising target for cancer therapy but its use is restricted by unwanted, devastating side effects. We explored whether intravesical instillation of the c-MYC inhibitor KSI-3716 could suppress tumor growth in murine orthotopic bladder xenografts.
  
  
  METHODS
  The small molecule KSI-3716, which blocks c-MYC/MAX binding to target gene promoters, was used as an intravesical chemotherapy agent. KSI-3716 action was assessed by electrophoretic mobility shift assay, chromatin immunoprecipitation, transcription reporter assay and quantitative reverse transcriptase-polymerase chain reaction. Inhibition of cell proliferation and its mechanism was monitored by cell cytotoxicity assay, EdU incorporation assay and flow cytometry. The in vivo efficacy of KSI-3716 was examined by noninvasive luminescence imaging and histological analysis after intravesical instillation of KSI-3716 in murine orthotopic bladder xenografts.
  
  
  RESULTS
  KSI-3716 blocked c-MYC/MAX from forming a complex with target gene promoters. c-MYC mediated transcriptional activity was inhibited by KSI-3716 at concentrations as low as 1 μM. The expression of c-MYC target genes, such as cyclin D2, CDK4 and hTERT, was markedly decreased. KSI-3716 exerted cytotoxic effects on bladder cancer cells by inducing cell cycle arrest and apoptosis. Intravesical instillation of KSI-3716 at a dose of 5 mg/kg significantly suppressed tumor growth with minimal systemic toxicity.
  
  
  CONCLUSIONS
  The c-MYC inhibitor KSI-3716 could be developed as an effective intravesical chemotherapy agent for bladder cancer.
authors.affiliation: Biomolecular Function Research Branch, National Cancer Center, Gyeonggi-do, Republic of Korea.
authors.forename: Kyung-Chae
authors.initials: KC
authors.lastname: Jeong
authors.affiliation: Molecular Epidemiology Branch, National Cancer Center, Gyeonggi-do, Republic of Korea.
authors.forename: Kyung-Tae
authors.initials: KT
authors.lastname: Kim
authors.affiliation: Genitourinary Cancer Branch, National Cancer Center, Gyeonggi-do, Republic of Korea.
authors.forename: Hye-Hyun
authors.initials: HH
authors.lastname: Seo
authors.affiliation: Genitourinary Cancer Branch, National Cancer Center, Gyeonggi-do, Republic of Korea.
authors.forename: Seung-Pil
authors.initials: SP
authors.lastname: Shin
authors.affiliation: Biomolecular Function Research Branch, National Cancer Center, Gyeonggi-do, Republic of Korea.
authors.forename: Kyung-Ohk
authors.initials: KO
authors.lastname: Ahn
authors.affiliation: Molecular Epidemiology Branch, National Cancer Center, Gyeonggi-do, Republic of Korea.
authors.forename: Min-Ju
authors.initials: MJ
authors.lastname: Ji
authors.affiliation: Center for Prostate Cancer, National Cancer Center, Gyeonggi-do, Republic of Korea.
authors.forename: Weon Seo
authors.initials: WS
authors.lastname: Park
authors.affiliation: Molecular Imaging and Therapy Branch, National Cancer Center, Gyeonggi-do, Republic of Korea.
authors.forename: In-Hoo
authors.initials: IH
authors.lastname: Kim
authors.affiliation: Genitourinary Cancer Branch, National Cancer Center, Gyeonggi-do, Republic of Korea. Electronic address: leesj@ncc.re.kr.
authors.forename: Sang-Jin
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Center for Prostate Cancer, National Cancer Center, Gyeonggi-do, Republic of Korea. Electronic address: seohk@ncc.re.kr.
authors.forename: Ho Kyung
authors.initials: HK
authors.lastname: Seo
mesh_terms: D042462:4-Quinolones / Q000008:administration & dosage / Q000037:antagonists & inhibitors*; D000283:Administration, Intravesical; D000814:Aniline Compounds / Q000008:administration & dosage / Q000037:antagonists & inhibitors*; D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D008807:Mice, Inbred BALB C; D016271:Proto-Oncogene Proteins c-myc / Q000037:antagonists & inhibitors*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy*; D023041:Xenograft Model Antitumor Assays
chemical_list: D042462:4-Quinolones; D000814:Aniline Compounds; D000970:Antineoplastic Agents; C587717:KSI-3716; C489428:Myc protein, mouse; D016271:Proto-Oncogene Proteins c-myc
keywords: 5-ethynyl-2′-deoxyuridine; CDK4; CRE; ChIP; DMSO; EdU; IC(50); PARP; PBS; PCR; PEG; RT-PCR; administration; chromatin immunoprecipitation; consensus response element; cyclin-dependent kinase 4; dimethyl sulfoxide; drug therapy; gene expression; hTERT; half inhibitory concentration; heterografts; human telomerase reverse transcriptase; intravesical; phosphate buffered saline; poly adenosine diphosphate ribose polymerase; polyethylene glycol; polymerase chain reaction; qRT-PCR; quantitative RT-PCR; reverse transcriptase-PCR; urinary bladder neoplasms