Preclinical demonstration of synergistic Active Nutrients/Drug (AND) combination as a potential treatment for malignant pleural mesothelioma

Our plain-English summary of Preclinical demonstration of synergistic Active Nutrients/Drug (AND) combination as a potential treatment for malignant pleural mesothelioma, by V. Volta, E. Ranzato, S. Martinotti, et al (PloS One, 2013).

The study

• Authors: V. Volta, E. Ranzato, S. Martinotti, S. Gallo, M.V. Russo, L. Mutti, S. Biffo, B. Burlando
• Journal: PloS One
• Published: 2013;8(3):e58051
• Cited by: 20 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Malignant pleural mesothelioma (MPM) is a poor prognosis disease lacking adequate therapy. We have previously shown that ascorbic acid administration is toxic to MPM cells. Here we evaluated a new combined therapy consisting of ascorbate/epigallocatechin-3-gallate/gemcitabine mixture (called AND, for Active Nutrients/Drug). In vitro effects of AND therapy on various MPM cell lines revealed a synergistic cytotoxic mechanism. In vivo experiments on a xenograft mouse model for MPM, obtained by REN cells injection in immunocompromised mice, showed that AND strongly reduced the size of primary tumor as well as the number and size of metastases, and prevented abdominal hemorrhage. Kaplan Meier curves and the log-rank test indicated a marked increase in the survival of AND-treated animals. Histochemical analysis of dissected tumors showed that AND induced a shift from cell proliferation to apoptosis in cancer cells. Lysates of tumors from AND-treated mice, analyzed with an antibody array, revealed decreased TIMP-1 and -2 expressions and no effects on angiogenesis regulating factors. Multiplex analysis for signaling protein phosphorylation exhibited inactivation of cell proliferation pathways. The complex of data showed that the AND treatment is synergistic in vitro on MPM cells, and blocks in vivo tumor progression and metastasization in REN-based xenografts. Hence, the AND combination is proposed as a new treatment for MPM.

In plain English

This was a laboratory and animal study. It did not study people or asbestos. The authors tested a mixture they called AND, made of ascorbate (vitamin C), EGCG (a green tea compound) and the cancer drug gemcitabine, against malignant pleural mesothelioma. In five human mesothelioma cell lines, the mixture worked synergistically, meaning the combination worked better than its parts would predict. The synergy was strongest in REN cells at middle-to-high levels of reduced cell viability. REN cells were then injected into the abdomens of immunodeficient mice, in four groups of 5. After 30 days, the Results reported that all treatments significantly reduced tumor number and weight, bleeding, and diaphragm tumor spread; the Discussion, however, said gemcitabine alone failed to reduce internal bleeding. AND gave the strongest reduction and no abdominal bleeding. In a survival experiment (6 mice per treated group, 10 controls), mice given AND or gemcitabine alone lived significantly longer than controls. AND and gemcitabine alone did not differ significantly. Tumors from AND-treated mice showed less cell growth and more cell death at their surface. The authors proposed testing AND in clinical trials in mesothelioma patients.

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: Preclinical laboratory study: experiments on human mesothelioma cell lines plus animal experiments in mice carrying human mesothelioma tumors (xenografts) in the abdominal cavity
• Who was studied: Five human malignant pleural mesothelioma cell lines (REN, MM98, BR95, NCI-H28, MPP89), and male NOD-SCID CB13 immunodeficient mice (6 to 8 weeks old) injected with REN cells. The tumor experiment used 4 groups of 5 mice. The survival experiment used 2 treated groups of 6 mice and a control group of 10 mice.
• Exposure: No asbestos exposure was studied. The mice were treated by injection into the abdominal cavity every 3rd day for 30 days with one of four options: gemcitabine alone (150 mg/kg); ascorbate (2,000 mg/kg) plus EGCG (30 mg/kg); the AND mixture (2,000 mg/kg ascorbate, 30 mg/kg EGCG, 100 mg/kg gemcitabine); or salt-water placebo. The survival experiment used lower, stepped-up gemcitabine doses: 30 then 50 mg/kg alone, or 20 then 30 mg/kg within AND.
• Main results:
  • In the cell lines, the AND mixture showed synergistic effects in all mesothelioma cells tested, to varying extents. The strongest synergism at mid-to-high levels of inhibited viability was in REN cells.
  • In mice after 30 days, the Results section reported that all treatments significantly reduced the number and weight of tumor masses, the degree of bleeding, and tumor coverage of the diaphragm, compared with placebo.
  • The Discussion, in contrast to the Results section, stated that gemcitabine alone failed to reduce internal bleeding.
  • Of the treatments, AND gave the strongest reduction in main tumor development and spread, and the AND-treated mice had no abdominal bleeding.
  • In tumors from AND-treated mice, most blood-vessel-related factors showed no significant change. The exceptions were TIMP-1 and TIMP-2, which were reduced.
  • AND treatment generally lowered the activation (phosphorylation) of signaling proteins involved in cell growth in the tumors.
  • In the survival experiment, mice treated with AND or with gemcitabine alone survived significantly longer than control-treated mice (p less than 0.05).
  • Most AND-treated mice survived longer than gemcitabine-treated mice, but this difference was not statistically significant. The AND mixture contained a lower gemcitabine dose.
  • At the surface of AND-treated tumors, cell growth dropped and programmed cell death (apoptosis) increased, compared with control tumors.
• The authors' conclusion: The authors concluded that AND was synergistic against mesothelioma cells in the laboratory and inhibited tumor growth in the mouse model, including at a reduced gemcitabine dose. They proposed it as a possible new treatment to be tested in mesothelioma patients in clinical trials.

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: Pleural Mesothelioma, Prognosis, Gemcitabine, Apoptosis, Angiogenesis.

Related studies

• In vitro screening of synergistic ascorbate-drug combinations for the treatment of malignant mesothelioma — S. Martinotti, E. Ranzato, et al. (2011)
• Synergistic antitumor activity of recombinant human Apo2L/tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in combination with carboplatin and pemetrexed in malignant pleural mesothelioma — G. Pasello, L. Urso, et al. (2014)
• Synergistic anti-tumor efficacy of immunogenic adenovirus ONCOS-102 (Ad5/3-D24-GM-CSF) and standard of care chemotherapy in preclinical mesothelioma model — L. Kuryk, E. Haavisto, et al. (2016)
• In vitro and in vivo therapeutic efficacy of the PPAR-γ agonist troglitazone in combination with cisplatin against malignant pleural mesothelioma cell growth — N. Hamaguchi, H. Hamada, et al. (2010)
• Synergistic inhibition of mesothelioma cell growth by the combination of clofarabine and resveratrol involves Nrf2 downregulation — Y.J. Lee, J.H. Im, et al. (2012)
• Impact of hypoxia on chemoresistance of mesothelioma mediated by the proton-coupled folate transporter, and preclinical activity of new anti-LDH-A compounds — G. Li Petri, B. El Hassouni, et al. (2020)

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