Virtual Library
Start Your Search
K.H. Sarun
Author of
-
+
OA02 - Novel Targets and Biomarkers in Malignant Pleural Mesothelioma (ID 369)
- Event: WCLC 2016
- Type: Oral Session
- Track: Mesothelioma/Thymic Malignancies/Esophageal Cancer/Other Thoracic Malignancies
- Presentations: 1
- Moderators:L.E. Raez, M. Jakopovic
- Coordinates: 12/05/2016, 11:00 - 12:30, Stolz 2
-
+
OA02.05 - Expression of miR-223 in Mesothelioma Xenografts Originates from Stromal Cells in the Tumour Microenvironment (ID 5875)
11:45 - 11:55 | Author(s): K.H. Sarun
- Abstract
- Presentation
Background:
Malignant pleural mesothelioma (MPM) is an aggressive cancer caused by asbestos exposure with limited therapeutic options. Dysregulated microRNAs play an important role in MPM biology and candidate microRNAs have been investigated as diagnostic and prognostic biomarkers or as a potential treatment targets. The role of miR-223 has previously been investigated in MPM tumour cells and was shown to act as a tumour suppressor by regulating cell mobility. Previous research indicated miR-223 to be primarily expressed by myeloid progenitor derived cells during differentiation of granulocytes and monocytes. This suggests miR-223 might have a more significant role in the inflammatory response during tumourigenesis. In this study we aimed to investigate the origin of miR-223 using mesothelioma xenograft and syngraft models.
Methods:
Human and mouse mesothelioma cell line-derived xenograft (MSTO-H211 and H226) and syngraft (AB1) models were established. MicroRNA profiles of xenografts were compared against profiles of their corresponding in vitro cultured cells to determine candidates. RT-qPCR using TaqMan MicroRNA assays was used to validate expression levels of miR-143-3p, miR-214-3p and miR-223-3p in tumour xenografts and syngrafts with those in corresponding cell lines in vitro. Species-specific ddPCR analysis was performed on RNA from xenograft tumours to determine the expression of human and mouse pri-miR-223.
Results:
MicroRNA profiles of xenograft tumours showed significant upregulation (p < 0.05) of miR-143-3p, miR-214-3p and miR-223-3p compared to corresponding in vitro mesothelioma cell lines. Only miR-223 showed significant upregulation in both xenograft and syngraft tumours compared to corresponding in vitro mesothelioma cell lines (>10000-fold increase). Other microRNAs were not significantly different between cell lines and tumours. RNA isolated from xenograft tumours contained significantly more mouse pri-miR-223 than human pri-miR-223 (p < 0.001), with only minimal expression levels of human tumour pri-miR-223 within xenograft tumours.
Conclusion:
Mature miR-223 is significantly overexpressed in xenograft tumours compared to corresponding in vitro mesothelioma cell lines suggesting stromal contribution. Species-specific pri-miRNA confirmed miR-223 is almost exclusively expressed by the mouse stromal cells in xenograft tumours. Ultimately, localising the expression of miR-223 to specific cell types (such as myeloid derived cells) through in situ hybridisation should help identify a more biologically relevant role for miR-223 in the tumour microenvironment.
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.
-
+
P3.03 - Poster Session with Presenters Present (ID 473)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Mesothelioma/Thymic Malignancies/Esophageal Cancer/Other Thoracic Malignancies
- Presentations: 1
- Moderators:
- Coordinates: 12/07/2016, 14:30 - 15:45, Hall B (Poster Area)
-
+
P3.03-008 - Hypoxia-Induced Changes in microRNA Levels Contribute to Drug Resistance in a 3D Model of Malignant Pleural Mesothelioma (ID 5867)
14:30 - 14:30 | Author(s): K.H. Sarun
- Abstract
Background:
Malignant pleural mesothelioma (MPM) is an aggressive asbestos-related thoracic cancer. Chemotherapy is the most frequent treatment option but almost every patient will be confronted with recurrence of disease and drug resistance. Previous studies have used 3D spheroid cultures to investigate drug response in MPM. We showed that microRNAs are important players in MPM biology and that they contribute to the response of MPM cells to some chemotherapy drugs. In the current study we aimed to investigate the role of microRNAs in the drug resistance of a 3D spheroid model of MPM.
Methods:
MPM cells were grown in standard 2D culture or as 3D spheroids in low adherence round bottom multi-well plates. The structure of the spheroids was confirmed by conventional and scanning electron microscopy. MicroRNA expression was profiled using TaqMan Low Density Arrays. RT-qPCR and droplet digital PCR were used to validate candidate microRNAs. HIF1a expression was examined in MPM spheroids using immunofluorescence staining. Drug cytotoxicity was investigated in both 2D and 3D cultures using standard proliferation assays, and the effect of drugs on gene expression was analysed. MicroRNA mimics and siRNAs were used to determine the influence of microRNA and HIF1a expression on drug resistance.
Results:
In our adapted model of 3D cell growth, MPM cell lines formed spherical 3D structures, in contrast to the donut shapes reported with other models. MPM cells in these spheroids were more resistant to cisplatin and gemcitabine when compared to cells grown in 2D cultures. Immunofluorescence revealed a hypoxic gradient with high HIF1a expression observed in the centre of the spheroids. Spheroids also exhibited a significant up-regulation of miR-210, miR-21, miR-378a, miR-195 and miR-146b, and down-regulation of miR-320b and miR-1225b. Transfecting MPM cells in 2D culture with miR-210 or miR-21 mimics resulted in increased drug resistance, whereas HIF1a knockdown inhibited spheroid formation and decreased drug resistance. Spheroids displayed higher expression of the ABCG2 drug pump, and ABCG2 was also up-regulated in cisplatin and gemcitabine treated MPM cells.
Conclusion:
Our spheroid model revealed a clear impact of hypoxia on gene expression in MPM cells. Hif1a was highly expressed in the hypoxic centre of the spheroids and is an upstream regulator of the microRNAs we found to be differentially expressed. Pharmacologic and genetic modulation of microRNA and HIF1a levels altered drug resistance in MPM cells, suggesting a link between hypoxia, microRNAs and drug resistance in MPM.
