Maslinic Acid, a Natural Triterpene, Induces a Death Receptor-Mediated Apoptotic Mechanism in Caco-2 p53-Deficient Colon Adenocarcinoma Cells

PLoS One. 2016 Jan 11;11(1):e0146178. doi: 10.1371/journal.pone.0146178. eCollection 2016.

Abstract

Maslinic acid (MA) is a natural triterpene present in high concentrations in the waxy skin of olives. We have previously reported that MA induces apoptotic cell death via the mitochondrial apoptotic pathway in HT29 colon cancer cells. Here, we show that MA induces apoptosis in Caco-2 colon cancer cells via the extrinsic apoptotic pathway in a dose-dependent manner. MA triggered a series of effects associated with apoptosis, including the cleavage of caspases -8 and -3, and increased the levels of t-Bid within a few hours of its addition to the culture medium. MA had no effect on the expression of the Bax protein, release of cytochrome-c or on the mitochondrial membrane potential. This suggests that MA triggered the extrinsic apoptotic pathway in this cell type, as opposed to the intrinsic pathway found in the HT29 colon-cancer cell line. Our results suggest that the apoptotic mechanism induced in Caco-2 may be different from that found in HT29 colon-cancer cells, and that in Caco-2 cells MA seems to work independently of p53. Natural antitumoral agents capable of activating both the extrinsic and intrinsic apoptotic pathways could be of great use in treating colon-cancer of whatever origin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / drug therapy*
  • Adenocarcinoma / genetics
  • Antineoplastic Agents / chemistry
  • Apoptosis*
  • Caco-2 Cells
  • Caspase 3 / metabolism
  • Caspase 8 / metabolism
  • Cell Proliferation
  • Colonic Neoplasms / drug therapy*
  • Colonic Neoplasms / genetics
  • Cytochromes c / metabolism
  • Drug Screening Assays, Antitumor
  • Flow Cytometry
  • Humans
  • Inhibitory Concentration 50
  • Membrane Potential, Mitochondrial
  • Mutation*
  • Receptors, Death Domain / metabolism*
  • Treatment Outcome
  • Triterpenes / chemistry*
  • Tumor Suppressor Protein p53 / genetics*

Substances

  • Antineoplastic Agents
  • Receptors, Death Domain
  • TP53 protein, human
  • Triterpenes
  • Tumor Suppressor Protein p53
  • Cytochromes c
  • maslinic acid
  • CASP3 protein, human
  • CASP8 protein, human
  • Caspase 3
  • Caspase 8

Grants and funding

This study was supported by grants Group BIO 157 from the Technology and Innovation Council of the Andalucian regional government and AGL2006-12210-C03-02/ALI, SAF2005-01627, ISCIII-RTICC (RD06/0020/0046) from the Spanish government and European Union FEDER funds.