In vitro killing of human malignant mesothelioma by photodynamic therapy

Our plain-English summary of In vitro killing of human malignant mesothelioma by photodynamic therapy, by S.M. Keller, D.D. Taylor, J.L. Weese (The Journal of Surgical Research, 1990).

The study

• Authors: S.M. Keller, D.D. Taylor, J.L. Weese
• Journal: The Journal of Surgical Research
• Published: 1990;48(4):337-40
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Photodynamic therapy was investigated as a potential new modality for the treatment of human malignant mesothelioma (HMM) utilizing the H-MESO-1 HMM cell line and the photosensitizing agent, Photofrin-II (PF-II). Up-take of PF-II by H-MESO-1 was documented by incubating H-MESO-1 cells with PF-II and measuring the fluorescence at 625 nm following excitation at 400 nm. Cytotoxicity of photodynamic therapy was determined by incubating H-MESO-1 cells (2 X 10(5)) in microtiter plates for 24 hr with concentrations of PF-II varying from 0 to 10 micrograms/ml. The wells were exposed to gold vapor laser light (628 nm) in doses ranging from 0 to 24,000 J/m2. Twenty-four hours following treatment, [3H]thymidine (1 microCi) was added to each well. Cells were harvested 24 hr later and counted for tritium incorporation. Five replicates were performed for each combination of light and drug. Peak absorption of PF-II by H-MESO-1 was reached within 8 hr. Maximal doses of light alone caused minimal cell killing. PF-II without light was cytotoxic only at the highest concentrations. However, the combination of PF-II at concentrations at or above 2.5 micrograms/ml and light produced a significant increase in cytotoxicity. These data demonstrate that photodynamic therapy can effectively kill human malignant mesothelioma cells in vitro.

In plain English

This was a laboratory study of cancer cells grown in plates, not of patients. The authors tested photodynamic therapy, in which a light-sensitive drug is activated by laser light, on H-MESO-1, a human malignant mesothelioma cell line taken from a patient with documented asbestos exposure and pleural mesothelioma. Cells received the drug Photofrin II (0 to 10 micrograms per ml) and gold vapor laser light (0 to 24,000 J per square meter). Killing was judged by reduced thymidine uptake compared with untreated cells. The cells reached half their maximum drug uptake by 2 hours and a plateau after 8 hours. Light alone caused minimal killing. The drug alone was toxic in proportion to its concentration. Drug plus light increased killing, and adding more drug or light left virtually no viable cells. A sustained statistical difference from controls was reached when the drug concentration exceeded 1.25 micrograms per ml. The authors concluded that photodynamic therapy can effectively kill these cells in vitro. They noted that animal testing, light delivery to the pleural space and safety for chest organs remained to be shown.

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: in vitro laboratory experiment on a cultured human cancer cell line
• Who was studied: The human malignant mesothelioma cell line H-MESO-1, obtained from Biomeasure, Inc. It originated from a patient with documented asbestos exposure and a classic pleural mesothelioma.
• Exposure: Photodynamic therapy. Cells were incubated for 24 hours with Photofrin II at 0 to 10 micrograms per ml, then exposed to gold vapor laser light (628 nm) at doses of 0 to 24,000 J per square meter. Asbestos was not tested.
• Main results:
  • H-MESO-1 cells reached 50% of maximum Photofrin II uptake by 2 hours, and uptake plateaued after 8 hours.
  • Laser light alone caused minimal killing of H-MESO-1 cells.
  • Photofrin II alone, without light, caused cytotoxicity proportional to drug concentration, which the authors called dark toxicity.
  • The combination of drug and light increased cytotoxicity. Adding more drug or light increased it until virtually no viable cells remained.
  • A sustained statistical difference from the no-light, no-drug controls was reached when the Photofrin II concentration exceeded 1.25 micrograms per ml.
• The authors' conclusion: The authors concluded that photodynamic therapy can effectively kill human malignant mesothelioma cells in vitro.
• Limitations the authors state:
  • The authors stated it remains to be shown whether uniform tumor-killing light doses can be delivered in the large, irregular pleural space.
  • The authors stated that no data exist on how lung tissue, heart, esophagus and diaphragm tolerate photodynamic therapy.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma.

Related studies

• Combination effect of photodynamic therapy using NPe6 with pemetrexed for human malignant pleural mesothelioma cells — S. Maehara, J. Usuda, et al. (2015)
• Illumination profile characterization of a light device for the dosimetry of intra-pleural photodynamic therapy for mesothelioma — C. Munck, S. Mordon, et al. (2016)
• Real-time light dosimetry for intra-cavity photodynamic therapy: Application for pleural mesothelioma treatment — N. Betrouni, C. Munck, et al. (2017)
• Phase III randomized trial of surgery with or without intraoperative photodynamic therapy and postoperative immunochemotherapy for malignant pleural mesothelioma — H.I. Pass, B.K. Temeck, et al. (1997)
• Radical pleurectomy and intraoperative photodynamic therapy for malignant pleural mesothelioma — J.S. Friedberg, M.J. Culligan, et al. (2012)
• Photodynamic therapy for lung cancer and malignant pleural mesothelioma — C.B. Simone, K.A. Cengel (2014)

Browse return to medical research.