miR-34a expression, cell cycle arrest and cell death of malignant mesothelioma cells upon treatment with radiation, docetaxel or combination treatment

Our plain-English summary of miR-34a expression, cell cycle arrest and cell death of malignant mesothelioma cells upon treatment with radiation, docetaxel or combination treatment, by T. Ghawanmeh, U. Thunberg, J. Castro, et al (Oncology, 2011).

The study

• Authors: T. Ghawanmeh, U. Thunberg, J. Castro, F. Murray, N. Laytragoon-Lewin
• Journal: Oncology
• Published: 2011;81(5-6):330-5
• Cited by: 34 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: Malignant mesothelioma (MM) is a highly aggressive tumour related to asbestos exposure. Histopathologically, the tumour is classified as epithelial, sarcomatoid or biphasic. To date, MM is still an incurable disease.

Methods: To evaluate treatment strategies on MM cells, the effects of radiotherapy, docetaxel or a combination of both on MM cells derived from the sarcomatoid type ZL34 and the epithelial type M28K were investigated. The TP53 gene, micro-RNA expression, cell cycle distribution and cell death were assessed as indicators of treatment effects.

Results: Despite the normal TP53 gene sequences in these cell lines, radiation-induced miR-34a expression was detected only in the M28K cells. Increasing G0/G1 cell numbers were detected in irradiated M28K and ZL34 cells. There was more radiation-induced cell death in M28K compared to ZL34 cells. The highest degree of cell cycle arrest at G2 and cell death in both cell types was obtained in the presence of docetaxel. The combination of docetaxel and radiation did not show any additive effects on miR-34a expression, cell cycle arrest or cell death in either the M28K or ZL34 cells.

Conclusion: Microtubule formation and other related functions by docetaxel might be the most suitable treatment modulation in both sarcomatoid and epithelial types of MM.

Copyright © 2012 S. Karger AG, Basel.

In plain English

This was a laboratory study of two malignant mesothelioma (MM) cell lines grown in culture. It did not study asbestos exposure and did not treat patients. ZL34 cells came from sarcomatoid-type MM and M28K cells from epithelial-type MM. The cells received 4 Gy of radiation, the chemotherapy drug docetaxel (0.6 µg/ml), or both. Both cell lines had normal TP53 gene sequences. Forty-eight hours after radiation, expression of miR-34a, a small regulatory RNA, rose in M28K cells but not in ZL34 cells. At 48 hours after radiation, 34% of M28K cells and 19% of ZL34 cells were dead. Docetaxel alone produced the highest share of cells halted at the G2 stage of cell division and the most cell death: 63% of M28K cells and 72% of ZL34 cells were dead at 24 hours. Combining radiation with docetaxel gave no advantage over docetaxel alone. The authors concluded that treatment with substances targeting cellular microtubules, such as docetaxel, appears to be the most effective approach in rapidly dividing epithelial and sarcomatoid MM cells.

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 mesothelioma cell lines; no patients or asbestos exposure studied
• Who was studied: Two established malignant mesothelioma cell lines: ZL34 (from sarcomatoid-type MM) and M28K (from epithelial-type MM); experiments done in Sweden
• Exposure: Not asbestos. The cells were treated with 4 Gy of radiation from a caesium-137 source, docetaxel at 0.6 µg/ml, or radiation followed immediately by docetaxel
• Main results:
  • Both the M28K and ZL34 cell lines had normal TP53 sequences in exons 4 to 8 (data not shown)
  • Forty-eight hours after 4 Gy of radiation, miR-34a expression was upregulated in M28K (epithelial) cells but not in ZL34 (sarcomatoid) cells
  • After radiation, 36% and 50% of M28K cells were in the G0/G1 stage at 24 and 48 h; for ZL34 cells the figures were 53% and 72%
  • With docetaxel at 48 h, 69% of epithelial-type cells (printed as 'M24K') and 54% of ZL34 cells were in the G2 stage; this was the highest G2 percentage seen
  • Spontaneous cell death in untreated control cultures was 8% and 11% at 24 and 48 h for M28K, and 2% for ZL34
  • Cell death after radiation was 12% in both cell lines at 24 h, rising to 34% (M28K) and 19% (ZL34) at 48 h
  • Docetaxel produced the highest cell death: 63% in M28K and 72% in ZL34 cultures by 24 h
  • Combination treatment caused 20% and 50% cell death at 24 and 48 h in M28K cultures, and 50% and 38% in ZL34 cultures
  • Combination treatment gave no advantage over docetaxel alone for G2 arrest or cell death
• The authors' conclusion: The authors concluded that treatment with substances targeting cellular microtubules (as docetaxel does), or related functions, appears to be the most effective treatment approach in highly dividing epithelial and sarcomatoid MM cells

Topics

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

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Asbestos Exposure, Sarcomatoid, Biphasic Mesothelioma.

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