Combinatorial anti-angiogenic gene therapy in a human malignant mesothelioma model

Our plain-English summary of Combinatorial anti-angiogenic gene therapy in a human malignant mesothelioma model, by S. Kubo, M. Takagi-Kimura, N. Kasahara (Oncology Reports, 2015).

The study

• Authors: S. Kubo, M. Takagi-Kimura, N. Kasahara
• Journal: Oncology Reports
• Published: 2015;34(2):633-8
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Anti-angiogenic gene therapy represents a promising strategy for cancer; however, it has rarely been tested in malignant mesothelioma, a highly aggressive tumor associated with asbestos with poor prognosis. In the present study, we investigated whether anti-angiogenic factors such as angiostatin, endostatin and the soluble form of vascular endothelial growth factor receptor 2 (sFlk1) were able to inhibit endothelial cell proliferation via lentivirus-mediated gene transfer into malignant mesothelioma cells in culture. We also assessed whether a dual-agent strategy had greater therapeutic benefit. Human malignant pleural mesothelioma MSTO-211H cells were transduced using lentiviral vectors that individually expressed angiostatin, endostatin and sFlk1 and linked to enhanced green fluorescent protein (EGFP) marker gene expression via an internal ribosome entry site. The lentivirus expressing EGFP alone was used as a control. The resultant cells designated as MSTO-A, MSTO-E, MSTO-F and MSTO-C were confirmed by western blot analysis and fluorescence microscopy to stably express the corresponding proteins. No differences were observed in the in vitro growth rates between any of these cells. However, co-culture of MSTO-A, MSTO-E and MSTO-F showed significant suppression of human umbilical endothelial cell growth in vitro compared with that of MSTO-C. Furthermore, a combination of any two among MSTO-A, MSTO-E and MSTO-F significantly enhanced efficacy. These results suggest that combinatorial anti-angiogenic gene therapy targeting different pathways of endothelial growth factor signaling has the potential for greater therapeutic efficacy than that of a single-agent regimen.

In plain English

This was a laboratory study of anti-angiogenic gene therapy in human malignant pleural mesothelioma cells, a tumour the authors describe as asbestos-induced. MSTO-211H cells were transduced with lentiviral vectors expressing angiostatin (LV-A), endostatin (LV-E) or soluble VEGF receptor 2, called sFlk1 (LV-F), each linked to an EGFP marker. A vector expressing EGFP alone (LV-C) served as the control. This produced the cell lines MSTO-A, MSTO-E, MSTO-F and MSTO-C. The cells were nearly 100% EGFP-positive, and the proteins were secreted into the culture medium. Cell morphology and in vitro growth over 7 days did not differ between the transduced lines (P greater than 0.05). Human umbilical vein endothelial cells (HUVEC) were co-cultured across a Transwell membrane. Their growth fell to 77.3±11.6% with MSTO-A (P=0.0191), 62.7±8.3% with MSTO-E (P=0.0009) and 62.2±1.5% with MSTO-F (P=0.0002), against 100.0±5.2% for MSTO-C. Mixing any two factor-expressing lines enhanced inhibition. In nude mice (n=10 per group), the single-factor mixtures C/A and C/E reduced tumour volume by 46.1-65.4% versus C/C (P less than 0.05). The two-factor combinations further enhanced the antitumour effect.

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 experimental study: lentiviral gene transfer into a human mesothelioma cell line, endothelial co-culture assays, and a subcutaneous xenograft experiment in nude mice
• Who was studied: Human malignant pleural mesothelioma MSTO-211H cells, normal human umbilical vein endothelial cells (HUVEC), and 6- to 7-week-old female BALB/c-nu/nu (nude) mice, 10 per group, followed for 12 weeks
• Exposure: Lentivirus-mediated transfer of anti-angiogenic genes (angiostatin LV-A, endostatin LV-E, soluble Flk1 LV-F) into mesothelioma cells, with an EGFP-only vector (LV-C) as control, giving the cell lines MSTO-A, MSTO-E, MSTO-F and MSTO-C. These were used singly and in 1:1 two-agent combinations. No asbestos was administered.
• Main results:
  • In vitro growth rates and morphology of the transduced mesothelioma cells did not differ between MSTO-A, MSTO-E, MSTO-F and MSTO-C (P greater than 0.05)
  • Co-culture with each single-factor mesothelioma line inhibited HUVEC proliferation relative to the EGFP control line, which was set at 100.0±5.2%
  • In 1:1 mixtures with control cells, the single-factor effects on HUVEC growth were weaker: C/A 88.5±8.8%, P=0.1404; C/E 85.6±6.3%, P=0.0557; C/F 80.6±7.7%, P=0.0266; C/C 100.0±7.6%. The two-factor combinations gave enhanced inhibition.
  • In the mouse xenografts, the single-factor mixtures C/A and C/E reduced tumour volume by 46.1-65.4% compared with the C/C group, and the two-factor combinations enhanced this further
• The authors' conclusion: The authors concluded that continuous in situ production of anti-angiogenic factors by combinatorial gene therapy has the potential for greater efficacy than a single-agent regimen
• Limitations the authors state:
  • The authors noted that anti-angiogenic therapy cannot by itself eradicate tumours and would require long-term and combination regimens in clinical use
  • The authors noted that the tumour reduction in mice was larger than expected from the co-culture data, suggesting an indirect effect in the animals that the co-culture assay did not capture

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, Prognosis, Pleural Mesothelioma.

Related studies

• Gene therapy using adenovirus carrying the herpes simplex-thymidine kinase gene to treat in vivo models of human malignant mesothelioma and lung cancer — H.C. Hwang, W.R. Smythe, et al. (1995)
• Current data on predictive markers for anti-angiogenic therapy in thoracic tumours — N. Reinmuth, M. Thomas, et al. (2010)
• Use of protamine to augment adenovirus-mediated cancer gene therapy — M. Lanuti, C.E. Kouri, et al. (1999)
• Replication-restricted vaccinia as a cytokine gene therapy vector in cancer: persistent transgene expression despite antibody generation — S. Mukherjee, T. Haenel, et al. (2000)
• Gene therapy for lung diseases: development in the vector biology and novel concepts for gene therapy applications — M. Suzuki, T. Matsuse, et al. (2001)
• Cytokine gene therapy or infusion as treatment for solid human cancer — B.W. Robinson, S.A. Mukherjee, et al. (1998)

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