Apoptosis

, Volume 12, Issue 3, pp 573–591

Acidic extracellular pH shifts colorectal cancer cell death from apoptosis to necrosis upon exposure to propionate and acetate, major end-products of the human probiotic propionibacteria

Authors

  • Annaïg Lan
    • UMR 1253 INRA AgrocampusScience & Technologie du Lait et de l’Oeuf, 65, rue de St Brieuc
    • Laboratoires Standa68 rue R. Kaskoreff
  • Dominique Lagadic-Gossmann
    • INSERM U620, Université Rennes1Faculté de Pharmacie, 2 av Prof Léon Bernard
  • Christophe Lemaire
    • CNRS UMR 8159, LGBCUniversité de Versailles
  • Catherine Brenner
    • CNRS UMR 8159, LGBCUniversité de Versailles
    • UMR 1253 INRA AgrocampusScience & Technologie du Lait et de l’Oeuf, 65, rue de St Brieuc
Article

DOI: 10.1007/s10495-006-0010-3

Cite this article as:
Lan, A., Lagadic-Gossmann, D., Lemaire, C. et al. Apoptosis (2007) 12: 573. doi:10.1007/s10495-006-0010-3

Abstract

The human probiotic Propionibacterium freudenreichii kills colorectal adenocarcinoma cells through apoptosis in vitro via its metabolites, the short chain fatty acids (SCFA), acetate and propionate. However, the precise mechanisms, the kinetics of cellular events and the impact of environmental factors such as pH remained to be specified. For the first time, this study demonstrates a major impact of a shift in extracellular pH on the mode of propionibacterial SCFA-induced cell death of HT-29 cells, in the pH range 5.5 to 7.5 prevailing within the colon. Propionibacterial SCFA triggered apoptosis in the pH range 6.0 to 7.5, a lethal process lasting more than 96 h. Indeed at pH 7.5, SCFA induced cell cycle arrest in the G2/M phase, followed by a sequence of cellular events characteristic of apoptosis. By contrast, at pH 5.5, the same SCFA triggered a more rapid and drastic lethal process in less than 24 h. This was characterised by sudden mitochondrial depolarisation, inner membrane permeabilisation, drastic depletion in ATP levels and ROS accumulation, suggesting death by necrosis. Thus, in digestive cancer prophylaxis, the observed pH-mediated switch between apoptosis and necrosis has to be taken into account in strategies involving SCFA production by propionibacteria to kill colon cancer cells.

Keywords

Cell deathColorectal cancerShort-chain fatty acids

Abbreviations

AV

annexinV-FITC

ΔΨm

mitochondrial transmembrane potential

DHE

dihydroethidium

DiOC6(3)

dihexyloxacarbocyanine iodide

Eth

Ethidium

Etop.

etoposide

FDA

fluorescein diacetate

IM

inner membrane

LND

lonidamine

O2.−

superoxide anion

Men

Menadione

PARP

poly-ADP-ribose polymerase

PCD

programmed cell death

PI

propidium iodide

PTPC

permeability transition pore complex

RIP

receptor-interacting protein

ROS

reactive oxygen species

SCFA

short-chain fatty acid

TNF

tumor necrosis factor

TRAIL

TNF α related apoptosis inducing ligand

Copyright information

© Springer Science+Business Media, LLC 2006