WIN induces apoptotic cell death inhuman colon cancer cells through a blockof autophagic flux dependent on PPARγdown-regulation

Anna De Blasio, Renza Vento, Giuseppe Calvaruso, Antonietta Notaro, Michela Giuliano, Selenia Sabella, Ornella Pellerito, Antonietta Notaro, Selenia Sabella, Anna De Blasio, Giuseppe Calvaruso, Michela Giuliano, Renza Vento

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)

Abstract

Cannabinoids have been reported to possess anti-tumorigenic activity in cancer models although their mechanism of action is not well understood. Here, we show that the synthetic cannabinoid WIN55,212-2 (WIN)-induced apoptosis in colon cancer cell lines is accompaniedby endoplasmic reticulum stress induction. The formation of acidic vacuoles and the increase in LC3-II protein indicated the involvement of autophagic process which seemed to play a pro-survival role against the cytotoxic effects of the drug. However, the enhanced lysosomal membrane permeabilization (LMP) blocked the autophagic flux after the formation of autophagosomes as demonstrated by the accumulation of p62 and LC3, two markersof autophagic degradation. Data also provided evidence for a role for nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) in cannabinoid signalling. PPARγ expression, at both protein and mRNA levels, was significantly down-regulated after WIN treatment and its inhibition, either by specific antagonists or by down-regulation via gene silencing, induced effects on cell viabilityas well as on ER stress and autophagic markers similar to those obtained in the presence of WIN. Moreover, the observation that the increase in p62 level and the induction of LMP were also modified by PPARγ antagonists seemed to indicate that PPARγ down-regulation was crucial to determinate the block of autophagic flux, thus confirming the critical role of PPARγ in WIN action. In conclusion, at our knowledge, our results are the first to show that the reduction of PPARγ levels contributes to WIN-induced colon carcinoma cell death by blocking the pro-survival autophagic response of cells.
Original languageEnglish
Pages (from-to)1029-1042
Number of pages14
JournalAPOPTOSIS
Volume19
Publication statusPublished - 2014

All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Pharmaceutical Science
  • Clinical Biochemistry
  • Cell Biology
  • Biochemistry, medical
  • Cancer Research

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