Defective autophagosome formation in p53-null colorectal cancer reinforces crocin-induced apoptosis

Amr Amin, Khuloud Bajbouj, Regine Schneider-Stock

Research output: Contribution to journalArticlepeer-review

57 Citations (Scopus)

Abstract

Crocin, a bioactive molecule of saffron, inhibited proliferation of both HCT116 wild-type and HCT116 p53-/- cell lines at a concentration of 10 mM. Flow cytometric analysis of cell cycle distribution revealed that there was an accumulation of HCT116 wild-type cells in G1 (55.9%, 56.1%) compared to the control (30.4%) after 24 and 48 h of crocin treatment, respectively. However, crocin induced only mild G2 arrest in HCT116 p53-/- after 24 h. Crocin induced inefficient autophagy in HCT116 p53-/- cells, where crocin induced the formation of LC3-II, which was combined with a decrease in the protein levels of Beclin 1 and Atg7 and no clear p62 degradation. Autophagosome formation was not detected in HCT116 p53-/- after crocin treatment predicting a nonfunctional autophagosome formation. There was a significant increase of p62 after treating the cells with Bafilomycin A1 (Baf) and crocin compared to crocin exposure alone. Annexin V staining showed that Baf-pretreatment enhanced the induction of apoptosis in HCT116 wild-type cells. Baf-exposed HCT116 p53-/- cells did not, however, show any enhancement of apoptosis induction despite an increase in the DNA damage-sensor accumulation, γH2AX indicating that crocin induced an autophagy-independent classical programmed cell death.

Original languageEnglish
Pages (from-to)1544-1561
Number of pages18
JournalInternational journal of molecular sciences
Volume16
Issue number1
DOIs
Publication statusPublished - Jan 9 2015

Keywords

  • Apoptosis
  • Autophagosome
  • Autophagy
  • Colorectal cancer
  • Crocin
  • p53

ASJC Scopus subject areas

  • Catalysis
  • Molecular Biology
  • Spectroscopy
  • Computer Science Applications
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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