Cisplatin and resveratrol induce apoptosis and autophagy following oxidative stress in malignant mesothelioma cells

Our plain-English summary of Cisplatin and resveratrol induce apoptosis and autophagy following oxidative stress in malignant mesothelioma cells, by Y.J. Lee, G.J. Lee, S.S. Yi, et al (Food and Chemical Toxicology, 2016).

The study

• Authors: Y.J. Lee, G.J. Lee, S.S. Yi, S.H. Heo, C.R. Park, H.S. Nam, M.K. Cho, S.H. Lee
• Journal: Food and Chemical Toxicology
• Published: 2016;97:96-107
• Cited by: 61 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant mesothelioma (MM) is characterized by poor responsiveness to current chemotherapeutic drugs, usually owing to high resistance to apoptosis. Here, we investigated chemosensitizing effects of phytochemical resveratrol, in combination with cisplatin, on MM cells. The combination treatment of cisplatin and resveratrol (CDDP/RSV) synergistically induced apoptosis, as evidenced by typical cell morphological changes, the appearance of sub-G0/G1 peak, an increase in the Annexin V(+) cells and the cleavage of caspase-3 and PARP. CDDP/RSV increased ROS production and depolarization of mitochondrial membrane potential with an increase in the Bax/Bcl-2 ratio. These changes were attenuated by pretreatment with N-acetylcysteine, suggesting that CDDP/RSV induced apoptosis through oxidative mitochondrial damage. Compared with MSTO-211H cells, CDDP/RSV was less efficient in killing H-2452 cells. H-2452 cells exhibited an enhanced autophagy to CDDP/RSV, as observed by an increase in viable cells exhibiting intense LysoTracker Red staining and up-regulation of Beclin-1 and LC3A. Inhibition of autophagy by bafilomycin A1 rendered cells more sensitive to CDDP/RSV-induced cytotoxicity and this was associated with induction of apoptosis. These data indicate that the increased resistance of H-2452 cells to CDDP/RSV is closely related to the activation of self-defensive autophagy, and provide the rationale for targeting the autophagy regulation in the treatment of MM.

Copyright © 2016 Elsevier Ltd. All rights reserved.

In plain English

This was a laboratory study of cells grown in dishes. It did not study patients or asbestos exposure. The authors tested the cancer drug cisplatin together with resveratrol, a plant compound, on two human malignant mesothelioma cell lines, MSTO-211H and H-2452. They chose doses that showed little toxicity in a normal human mesothelial cell line, MeT-5A. After 48 hours the combination worked synergistically. Measured by the MTT assay as a percentage of vehicle-treated control cells, relative cell viability with the combination was 47.5% for MSTO-211H and 71.2% for H-2452. It was 71.8% and 95.9% with cisplatin alone, and 64.7% and 93.4% with resveratrol alone. The combination increased markers of programmed cell death (apoptosis), reactive oxygen species and mitochondrial damage, more so in MSTO-211H cells. The antioxidant N-acetylcysteine reduced these changes. H-2452 cells showed stronger autophagy, a cellular self-recycling process. Blocking autophagy with bafilomycin A1 made the combination kill more of these cells. The authors concluded that the greater resistance of H-2452 cells is closely related to self-defensive autophagy. They said this provides a rationale for targeting autophagy in treating mesothelioma.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory (in vitro) experiment on human cell lines grown in culture
• Who was studied: Two human malignant mesothelioma cell lines (MSTO-211H and H-2452) and one normal human mesothelial cell line (MeT-5A), obtained from the American Type Culture Collection. No patients were studied.
• Exposure: Treatment with cisplatin (CDDP) and resveratrol (RSV), alone or combined, mainly for 48 hours. The article prints the doses as 40 mM for CDDP and 30 mM for RSV. These doses were chosen because they showed little toxicity in normal MeT-5A cells. Some experiments added pretreatment with N-acetylcysteine (an antioxidant) or bafilomycin A1 (an autophagy blocker). Asbestos was not studied.
• Main results:
  • Alone, cisplatin's 50% inhibition concentration was 280 ± 4 in MSTO-211H cells and 381 ± 7 in H-2452 cells. Resveratrol's was 99 ± 5 and 106 ± 1, respectively. The article prints the unit as mM.
  • After 48 hours the combination was synergistic, with a combination index of 0.4 in MSTO-211H cells and 0.7 in H-2452 cells.
  • Relative cell viability was measured by the MTT assay as a percentage of vehicle-treated control cells. With the combination it was 47.5% in MSTO-211H cells and 71.2% in H-2452 cells. With cisplatin alone it was 71.8% and 95.9%, and with resveratrol alone 64.7% and 93.4%.
  • Annexin V-positive (apoptotic) cells after the combination: 49.66% in MSTO-211H cells and 24.41% in H-2452 cells.
  • The combination increased reactive oxygen species production to about 52.26% in MSTO-211H cells and 27.09% in H-2452 cells.
  • The percentage of cells with loss of mitochondrial membrane potential rose to 46.13% in MSTO-211H cells and 34.93% in H-2452 cells.
  • Pretreatment with N-acetylcysteine reduced the combination-induced rise in reactive oxygen species to about 24.59% in MSTO-211H cells and 14.81% in H-2452 cells. It also inhibited cleavage of the apoptosis markers procaspase-3 and PARP.
  • Silencing p53 did not significantly change cell viability compared with control siRNA.
  • Compared with MSTO-211H cells, H-2452 cells showed much higher accumulation of the autophagy markers Beclin-1 and LC3A after the combination.
  • Blocking autophagy with bafilomycin A1 significantly increased combination-induced cell killing in H-2452 cells, and to a lesser degree in MSTO-211H cells.
• The authors' conclusion: The authors concluded that the greater resistance of H-2452 cells to the combination is closely related to activation of self-defensive autophagy. In their view, the data provide a rationale for targeting autophagy regulation in treating malignant mesothelioma.
• Limitations the authors state:
  • The authors did not confirm whether the rise in reactive oxygen species leads to the loss of mitochondrial membrane potential, or the reverse.
  • The authors state that the interplay between reactive oxygen species and autophagy needs further investigation.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Cisplatin, Apoptosis, Oxidative Stress, Mesothelioma.

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