HepaCAM inhibits the malignant behavior of castration-resistant prostate cancer cells by downregulating Notch signaling and PF-3084014 (a γ-secretase inhibitor) partly reverses the resistance of refractory prostate cancer to docetaxel and enzalutamide in vitro

Int J Oncol. 2018 Jul;53(1):99-112. doi: 10.3892/ijo.2018.4370. Epub 2018 Apr 12.

Abstract

Castration-resistant prostate cancer (CRPC) continues to be a major challenge in the treatment of prostate cancer (PCa). The expression of hepatocyte cell adhesion molecule (HepaCAM), a novel tumor suppressor, is frequently downregulated or lost in PCa. Overactivated Notch signaling is involved in the development and progression of PCa, including CRPC. In this study, we found that the activities of Notch signaling were elevated, while HepaCAM expression was decreased in CRPC tissues compared with matched primary prostate cancer (PPC) tissues. In addition, HepaCAM negativity was found to be associated with a worse progression‑free survival (PFS). Furthermore, the overexpression of HepaCAM induced by transfection with a HepaCAM overexpression vector (Ad‑HepaCAM) exerted antitumor effects by decreasing the proliferation, and suppressing the invasion and migration of bicalutamide‑resistant (Bica‑R) cells and enzalutamide‑resistant (Enza‑R) cells. Importantly, we found that the antitumor effects of HepaCAM on the resistant cells were associated with the downregulation of Notch signaling. Moreover, we revealed that PF‑3084014 (a γ‑secretase inhibitor) re‑sensitized Enza‑R cells to enzalutamide, and sequential dual‑resistant (E+D‑R) cells to docetaxel. Additionally, the findings of this study demonstrated that the use of PF‑3084014 alone exerted potent antitumor effect on the resistant cells in vitro. On the whole, this study indicates that HepaCAM potentially represents a therapeutic target and PF‑3084014 may prove to a promising agent for use in the treatment of refractory PCa.

MeSH terms

  • Adult
  • Aged
  • Amyloid Precursor Protein Secretases / antagonists & inhibitors
  • Benzamides
  • Cell Cycle Proteins
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Disease-Free Survival
  • Docetaxel
  • Drug Resistance, Neoplasm / genetics*
  • Humans
  • Male
  • Middle Aged
  • Nitriles
  • Phenylthiohydantoin / administration & dosage
  • Phenylthiohydantoin / adverse effects
  • Phenylthiohydantoin / analogs & derivatives
  • Prostate / drug effects
  • Prostate / pathology
  • Prostatic Neoplasms, Castration-Resistant / drug therapy*
  • Prostatic Neoplasms, Castration-Resistant / genetics
  • Prostatic Neoplasms, Castration-Resistant / pathology
  • Proteins / genetics*
  • Receptors, Notch / antagonists & inhibitors
  • Receptors, Notch / genetics
  • Signal Transduction / drug effects
  • Taxoids / administration & dosage
  • Taxoids / adverse effects
  • Tetrahydronaphthalenes / administration & dosage*
  • Valine / administration & dosage
  • Valine / analogs & derivatives*
  • Xenograft Model Antitumor Assays

Substances

  • Benzamides
  • Cell Cycle Proteins
  • HEPACAM protein, human
  • Nitriles
  • Proteins
  • Receptors, Notch
  • Taxoids
  • Tetrahydronaphthalenes
  • Docetaxel
  • Phenylthiohydantoin
  • enzalutamide
  • Amyloid Precursor Protein Secretases
  • Valine
  • nirogacestat