title: Evaluation of the first Ergocalciferol-derived, non hypercalcemic anti-cancer agent MT19c in ovarian cancer SKOV-3 cell lines.
abstract: OBJECTIVE
  In human trials calcitriol and its analogs displayed unacceptable systemic toxicities including hypercalcemia. This study was designed to evaluate a novel non-hypercalcemic vitamin-D derivative (MT19c) and its anticancer effects in cultured ovarian cancer cell model.
  
  
  METHODS
  We modified the Ergocalciferol structure to generate MT19c, a heterocyclic vitamin-D derivative. Hypercalcemic liabilities of MT19c were assessed by estimating the blood calcium levels in drug treated animals. VDR agonistic or antagonistic properties of MT19c were determined via a VDR-coactivator binding assay. The anticancer effects of MT19c were evaluated by (i) cytotoxicity studies in cancer cell lines and the National Cancer Institute (NCI(60)) cell lines, (ii) identification of apoptosis markers by microscopy and western blots, (iii) cell cycle analysis, and (iv) by studying the insulin receptor substrate-1/2 (IRS1/2) signaling in ovarian cancer cells (SKOV-3) by western blotting.
  
  
  RESULTS
  MT19c treatment did not cause hypercalcemia in mice and showed minor VDR antagonistic activity. In a NCI(60) screen MT19c revealed cell-type specific growth inhibition. MT19c displayed superior cytotoxicity to cisplatin, calcitriol, EB1089 and Iressa in SKOV-3 cell-lines and was comparable to Taxol in our in vitro assays. In SKOV-3 cells MT19c showed caspase dependent apoptosis, DNA fragmentation and cell cycle arrest. MT19c did not alter VDR but downregulated the IGFR/IRS-1/2-MEK-ras-ERK1/2-pathway via activated TNFα-receptor/SAPK/JNK component.
  
  
  CONCLUSIONS
  Our results demonstrate how structural optimization of the vitamin-D scaffold leads to identification of a non-hypercalcemic compound MT19c which exerts cytotoxicity in vitro based on a VDR-independent signaling pathway and displays potent anti-cancer activity in ovarian cancer cell models.
authors.affiliation: Department of Obstetrics and Gynecology, Alpert Medical School, Brown University, Providence, RI 02905, USA.
authors.forename: Laurent
authors.initials: L
authors.lastname: Brard
authors.forename: Thilo S
authors.initials: TS
authors.lastname: Lange
authors.forename: Katina
authors.initials: K
authors.lastname: Robison
authors.forename: Kyu Kwang
authors.initials: KK
authors.lastname: Kim
authors.forename: Tahniyath
authors.initials: T
authors.lastname: Ara
authors.forename: Megan Marie
authors.initials: MM
authors.lastname: McCallum
authors.forename: Leggy A
authors.initials: LA
authors.lastname: Arnold
authors.forename: Richard G
authors.initials: RG
authors.lastname: Moore
authors.forename: Rakesh K
authors.initials: RK
authors.lastname: Singh
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002118:Calcium / Q000097:blood; D045744:Cell Line, Tumor; D004872:Ergocalciferols / Q000494:pharmacology*; D005260:Female; D006801:Humans; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D010051:Ovarian Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D018167:Receptors, Calcitriol / Q000037:antagonists & inhibitors
chemical_list: D000970:Antineoplastic Agents; D004872:Ergocalciferols; C568376:MT19c compound; D018167:Receptors, Calcitriol; D020928:Mitogen-Activated Protein Kinases; D002118:Calcium