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J. Varano
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MO19 - Lung Cancer Immunobiology (ID 91)
- Event: WCLC 2013
- Type: Mini Oral Abstract Session
- Track: Biology
- Presentations: 1
- Moderators:Y. Sekido, J. Minna
- Coordinates: 10/30/2013, 10:30 - 12:00, Bayside 201 - 203, Level 2
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MO19.06 - The role of fibroblast growth factor-9 in the regulation of the tumour-specific immune response in malignant mesothelioma (ID 3237)
11:00 - 11:05 | Author(s): J. Varano
- Abstract
- Presentation
Background
Identifying key molecules in the pathobiology of malignant mesothelioma is needed to develop new therapies and biomarkers. Fibroblast growth factor-9 (FGF-9) is an exciting and novel target uncovered from our global gene profiling of human MPM samples. Recently FGF-9 has been implicated in cancer development and neoplastic transformation of embryonic fibroblasts. We have verified over-expression of FGF-9 in MPM over other cancers and benign pleuritis in five separate cohorts of human pleural tissues and effusions. Our preliminary in vitro work demonstrated that FGF-9 induces mesothelioma cell proliferation and matrix invasion. We therefore hypothesised that antagonising FGF-9 may reduce tumour aggressiveness, growth and induce tumour regression in vivo.Methods
To study the ‘necessity’ of FGF-9 in MPM development in vivo we transfected the mouse MM cell line, AB1, with shRNA directed against murine FGF-9 (or control vector expressing a scrambled sequence). For the heterotopic model murine AB1-FGF-9 knock-down cells (or controls) were injected (5x10[5 ]cells) subcutaneously into the flank of Balb/c mice. Tumour dimensions were measured thrice weekly and animals sacrificed when tumours reached 100mm[2] and tumour tissues harvested. FGF-9 expression in tumour tissue was determined by immunohistochemistry. For orthotopic experiments, Balb/c mice received a single intraperitoneal injection of 5x10[5 ]AB1-FGF-9 knock-down cells (or controls). At day 13, animals were sacrificed and the number of peritoneal tumour nodules enumerated by blinded investigators. To determine whether the immune system plays a role in the regulation of AB1 MM tumour growth, 5x10[5 ]AB1-FGF-9 knock-down cells (or controls) were injected subcutaneously into nude mice. To elucidate the immune cells involved in AB1 MM tumour growth regulation, T cells were depleted in Balb/c tumour bearing mice using specific antibodies to CD4 and CD8 and tumour growth monitored. T cell depletion was confirmed using flow cytometry.Results
Heterotopic tumour growth was significantly retarded in mice inoculated with AB1-FGF-9 knockdown cells compared to the scrambled vector and parent MM cells (p<0.001). A significant reduction in the number, and hence tumour burden, of tumour nodules was also observed for AB1-FGF-9 knockdown tumours in the orthotopic peritoneal model compared to controls (p<0.001). When grown in nude mice, which lack a functional T cell repertoire, AB1-FGF-9 knockdown tumours grew at a similar rate to that of the parent and vector controls which was suggestive of a role of the immune response in the regulation of MM tumours lacking FGF-9. AB1-FGF-9 knockdown tumours demonstrated significantly greater tumour burden in mice depleted of CD4+ and CD8+ T cells, either alone or in combination, when compared to saline controls which is highly suggestive of a T cell-mediated immune response to these tumours. These results also suggest that FGF-9 inhibits the tumour-specific immune response in MM.Conclusion
In combination with our previous in vitro data which clearly demonstrated the proliferative and invasive properties of FGF-9, we suggest that FGF-9 has an important role in the pathobiological characteristics of MM in vivo and represents a novel therapeutic target.Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.
