Sabutoclax, a Mcl-1 antagonist, inhibits tumorigenesis in transgenic mouse and human xenograft models of prostate cancer

Neoplasia. 2012 Jul;14(7):656-65. doi: 10.1593/neo.12640.

Abstract

Resistance to available therapeutic agents has been a common problem thwarting progress in treatment of castrate-resistant and metastatic prostate cancer (PCa). Overexpression of the Bcl-2 family members, including Mcl-1, in PCa cells is known to inhibit intracellular mitochondrial-dependent apoptosis. Here we report the development of a novel transgenic mouse model that spontaneously develops prostatic intraepithelial neoplasia and adenocarcinoma by the inducible, conditional knockout of transforming growth factor β receptor type II in stromal fibroblastic cells (Tgfbr2(ColTKO)). The Tgfbr2(ColTKO) prostate epithelia demonstrated down-regulation of luminal and basal differentiation markers, as well as Pten expression and up-regulation of Mcl-1. However, unlike in men, Tgfbr2(ColTKO) prostates exhibited no regression acutely after castration. The administration of Sabutoclax (BI-97C1), a pan-active Bcl-2 protein family antagonist mediated apoptosis in castrate-resistant PCa cells of Tgfbr2(ColTKO) mice and human subcutaneous, orthotopic, and intratibial xenograft PCa models. Interestingly, Sabutoclax had little apoptotic effect on benign prostate tissue in Tgfbr2(ColTKO) and wild-type mice. Sabutoclax was able to block c-Met activation, a critical axis in PCa metastatic progression. Further, Sabutoclax synergistically sensitized PC-3 cells to the cytotoxic effects of docetaxel (Taxotere). Together, these data suggest that Sabutoclax inhibits castrate-resistant PCa alone at the primary and bone metastatic site as well as support sensitivity to docetaxel treatment.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Antineoplastic Agents / administration & dosage
  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents / therapeutic use*
  • Apoptosis / drug effects
  • Apoptosis / genetics
  • Bone Neoplasms / drug therapy
  • Bone Neoplasms / metabolism
  • Bone Neoplasms / secondary
  • Cell Transformation, Neoplastic / drug effects*
  • Cell Transformation, Neoplastic / metabolism
  • Disease Progression
  • Docetaxel
  • Drug Synergism
  • Gossypol / administration & dosage
  • Gossypol / analogs & derivatives*
  • Gossypol / pharmacology
  • Gossypol / therapeutic use
  • Humans
  • Male
  • Mice
  • Mice, Transgenic
  • Myeloid Cell Leukemia Sequence 1 Protein
  • Orchiectomy
  • Prostatic Neoplasms / drug therapy*
  • Prostatic Neoplasms / metabolism
  • Prostatic Neoplasms / pathology
  • Proto-Oncogene Proteins c-bcl-2 / antagonists & inhibitors*
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Proto-Oncogene Proteins c-met / metabolism
  • Signal Transduction / drug effects
  • Taxoids / administration & dosage
  • Taxoids / pharmacology
  • Tumor Burden / drug effects
  • Xenograft Model Antitumor Assays

Substances

  • 1,1',6,6',7,7'-hexahydroxy-3,3'-dimethyl-N5-(2-phenylpropyl)-N5'-(2-phenylpropyl)-2,2'-binaphthyl-5,5'-dicarboxamide
  • Antineoplastic Agents
  • Mcl1 protein, mouse
  • Myeloid Cell Leukemia Sequence 1 Protein
  • Proto-Oncogene Proteins c-bcl-2
  • Taxoids
  • Docetaxel
  • Proto-Oncogene Proteins c-met
  • Gossypol