Characterization and drug sensitivity profiling of primary malignant mesothelioma cells from pleural effusions

Our plain-English summary of Characterization and drug sensitivity profiling of primary malignant mesothelioma cells from pleural effusions, by A. Szulkin, R. Otvös, C.O. Hillerdal, et al (BMC Cancer, 2014).

The study

• Authors: A. Szulkin, R. Otvös, C.O. Hillerdal, A. Celep, E. Yousef-Fadhel, H. Skribek, A. Hjerpe, L. Székely, K. Dobra
• Journal: BMC Cancer
• Published: 2014;14:709
• Cited by: 30 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Patients with malignant mesothelioma have a poor prognosis and only 40% respond to first line treatment; a combination of pemetrexed and cisplatin or carboplatin. We used primary malignant mesothelioma cells and an ex vivo chemosensitivity assay with future purpose to predict best choice of treatment. The clinical outcome of these patients might be predicted by measuring drug sensitivity.

Methods: Pleural effusions containing primary malignant mesothelioma cells were received from the diagnostic routine. We characterized and tested the chemosensitivity of 18 malignant samples and four benign samples from 16 different patients with pleural effusions. Cells were seeded in a 384-well plate for a robotized ex vivo testing of drug sensitivity to 32 different drugs. The primary cells were further characterized by immunocytochemistry to evaluate the proportion of malignant cells and to study the RRM1 and ERCC1 reactivity, two proteins associated with drug resistance.

Results: We observed great individual variability in the drug sensitivity. Primary cell isolates were affected by between one and ten drugs, and resistant to the remaining tested drugs. Actinomycin D and daunorubicin were the two drugs effective in most cases. Adjusting efficiency of individual drugs for varying proportion of tumor cells and to the average effect on benign cells correlated with effect of pemetrexed, cisplatin and survival time. General drug sensitivity, proportion of malignant cells and reactivity to RRM1 correlated to each other and to survival time of the patients.

Conclusions: The proportion of malignant cells and RRM1 reactivity in the pleural effusions correlate to drug sensitivity and survival time. The variability in response to the commonly used chemotherapies emphasizes the need for tests that indicate best individual choice of cytotoxic drugs. The efficiency of the obtained results should preferably be corrected for admixture of benign cells and effects of given drugs on benign cells.

In plain English

This laboratory study tested how mesothelioma cells from pleural effusions (fluid around the lungs) responded to chemotherapy drugs. Cells came from twelve patients with malignant mesothelioma, four patients without a malignant diagnosis, and five mesothelioma cell lines. They exposed the cells to 32 drugs for 72 hours. The study did not examine asbestos exposure. Sensitivity varied widely: the most resistant cultures were affected by one drug, the most sensitive by ten. Actinomycin D and daunorubicin affected 10 of the 18 malignant cultures, though some of these drugs also affected two or three benign samples. Cisplatin, carboplatin, pemetrexed and bortezomib had limited effect, but pemetrexed was tested on only half the samples. A higher proportion of malignant cells correlated with fewer effective drugs (p = 0.037). RRM1 protein staining also correlated with the number of effective drugs (p = 0.0037). Patients' survival time correlated with the proportion of effective drugs (p = 0.036). Its correlations with malignant cell proportion and RRM1 staining were not statistically significant. The authors concluded these factors seemed to correlate with each other and with survival, and that the trends need evaluation in larger cohorts.

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 (ex vivo) study testing the drug sensitivity of primary mesothelioma cells grown from pleural effusions, with staining for RRM1 and ERCC1 and comparison with patient survival time
• Who was studied: Primary cells from pleural effusions of twelve patients diagnosed with malignant mesothelioma (18 malignant cell cultures in total), benign mesothelial cells from four patients with no malignant diagnosis, and five mesothelioma cell lines
• Exposure: Asbestos exposure was not studied. Cells were exposed in the laboratory to 32 chemotherapy drugs at four concentrations for 72 hours.
• Main results:
  • Drug sensitivity varied greatly between cultures. The most resistant malignant cultures were affected by one drug and the most sensitive by ten drugs.
  • Actinomycin D and daunorubicin were the most effective drugs, affecting 10 of the 18 malignant cell cultures. Some of these drugs also affected two or three of the benign samples.
  • Bortezomib, cisplatin, carboplatin and pemetrexed had limited effect on the malignant cells. Pemetrexed was tested on only 50% of the samples.
  • The proportion of malignant cells in the cultures (10-98%) correlated inversely with the proportion of effective drugs (p = 0.037). Its correlation with patients' overall survival was not statistically significant.
  • Patients' survival time correlated with the proportion of effective drugs (p = 0.036) and with the sensitivity score (p = 0.0054). It did not correlate with drug efficiency or adjusted drug efficiency.
  • RRM1 staining correlated with the number of effective drugs (p = 0.0037) but not with survival time.
  • Cultures with higher RRM1 staining scores were more resistant to several drugs.
  • ERCC1 staining did not correlate with the proportion of effective drugs or with patient survival time.
  • In nine patients, drug efficiency was adjusted for the proportion of malignant cells and for drug effects on benign cells. This adjustment increased the tendency of pemetrexed, cisplatin and doxorubicin efficiency to correlate with survival (p = 0.09, p = 0.05 and p = 0.17, respectively).
  • Hyaluronan levels in the effusions correlated with RRM1 staining in the twelve patient samples (p = 0.024) but not with survival time.
• The authors' conclusion: The authors concluded that drug sensitivity, the amount of malignant cells and RRM1 reactivity seemed to correlate with each other and with patient survival time. They also concluded that the variable response to common drugs shows a need for tests that indicate the best individual choice of drugs.
• Limitations the authors state:
  • The mix of benign cells in the samples, and how those cells react to the drugs, are confounding factors that must be dealt with.
  • Culturing cells for a long time may change how they respond to drugs.
  • The test may underestimate pemetrexed's effect; the authors note that analysing the cell cycle is a more sensitive way to detect this drug's short-term effect.
  • The trends seen still need evaluation in larger patient cohorts.

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: Mesothelioma, Pleural Effusion, Prognosis, Pemetrexed (Alimta), Cisplatin, Carboplatin.

Related studies

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• RRM1 and ERCC1 as biomarkers in patients with locally advanced and metastatic malignant pleural mesothelioma treated with continuous infusion of low-dose gemcitabine plus cisplatin — W. Muñoz-Montaño, S. Muñiz-Hernández, et al. (2021)
• Variation in drug sensitivity of malignant mesothelioma cell lines with substantial effects of selenite and bortezomib, highlights need for individualized therapy — A. Szulkin, G. Nilsonne, et al. (2013)
• Correlation between TS, MTHFR, and ERCC1 gene polymorphisms and the efficacy of platinum in combination with pemetrexed first-line chemotherapy in mesothelioma patients — T. Powrózek, D.M. Kowalski, et al. (2014)
• The mesothelioma enigma — R.M. Flores (2015)
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