Virtual Library
Start Your Search
Mei-Lin Chan
Author of
-
+
MA12 - Mesothelioma Surgery and Novel Targets for Prognosis and Therapy (ID 913)
- Event: WCLC 2018
- Type: Mini Oral Abstract Session
- Track: Mesothelioma
- Presentations: 1
- Moderators:
- Coordinates: 9/25/2018, 10:30 - 12:00, Room 202 BD
-
+
MA12.10 - Long-Term Impact of Radiotherapy Before Surgery for Mesothelioma on the Distribution of Memory T Cell Subsets (ID 12728)
11:35 - 11:40 | Author(s): Mei-Lin Chan
- Abstract
- Presentation
Background
Postoperative recurrence remains one of the critical issues in treatments for mesothelioma. We previously reported that non-ablative, hypo-fractionated radiation before surgery generated an antigen-specific activation of the immune system and could provide an in situ vaccination with long-term protection against mesothelioma in our murine model. An effective immunological protection depends on memory T cell subset diversification. However, limited work has been done to address the distribution of memory T cell subsets and its effects on the immune system after radiotherapy followed by surgery for mesothelioma.
a9ded1e5ce5d75814730bb4caaf49419 Method
C57BL/6 mice bearing AE17-OVA tumor were treated with local radiotherapy (LRT). LRT 5Gy was delivered on days 10, 11 and 12. We performed radical tumor resection 7 days after LRT. The mice were re-challenged under the skin or into thoracic cavity with AE17-OVA 28 days after surgery and defined as immunological protective memory model if the tumors were completely rejected. Memory model received subcutaneous tumor inoculation once again (second rechallenge), samples were harvested on day 0, 3, 10. We investigated memory T cell subsets using flow cytometry. In addition, the harvested total splenocytes (effector) were co-cultured with CFSE-labeled AE17-OVA (target) for three days. Each of their cytotoxic potential was analyzed by evaluating a number of AE17-OVA and its early or late apoptosis.
4c3880bb027f159e801041b1021e88e8 Result
8 out of 10 mice completely rejected the subcutaneous tumor in mice treated with LRT and surgery after re-challenged. We observed significantly better survival in the memory model re-challenged into the thoracic cavity compared with no treatment mice. After subcutaneous tumor inoculation, central memory T cells (CD44[+]CD62L[+]KLRG1[-]) on day 0, effector memory T cells (CD44[+]CD62L[-]KLRG1[-]) and terminal effector T cells (CD44[+]CD62L[-]KLRG1[+]) on day 0, 3, 10 increased significantly in CD8[+] splenocytes of memory model compared with no treatment mice. This observation was also seen in draining and non-draining lymph nodes. The MFI of CFSE reflecting a number of AE17-OVA cells decreased, whereas the proportion of early (Annexin V[+]FVD[low]) or late (Annexin V[+]FVD[high]) apoptotic cells in CFSE[+] cells increased, depending on time passage and effector/target ratio after tumor inoculation in both memory model and naïve mice. However, during time passage, memory model always had a stronger cytotoxicity (even at Day 0) as compared to naïve mice.
8eea62084ca7e541d918e823422bd82e Conclusion
Our data raise an important possibility that non-ablative, hypo-fractionated radiotherapy followed by surgery for mesothelioma contributes to the development and long-term maintenance of memory T cell subsets, which could remain poised to rapidly recall effector functions upon antigen re-exposure.
6f8b794f3246b0c1e1780bb4d4d5dc53Only 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.
-
+
P2.06 - Mesothelioma (Not CME Accredited Session) (ID 955)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
-
+
P2.06-38 - Mesothelioma Stem Cells May Be the Critical Factor of Treatment Failure (ID 11344)
16:45 - 18:00 | Author(s): Mei-Lin Chan
- Abstract
Background
Cancer cell repopulation during treatments of chemotherapy or radiotherapy is a major factor resulting in treatment failure. It has been indicated that cancer stem cells (CSC) may play critical roles during this process. The goal of our study is to characterise mesothelioma stem cells (MSC) and evaluate the prognostic values in those patients with malignant pleural mesothelioma (MPM). The eventual aim would be to design specific target therapy against MSC and develop novel approaches in clinical practice.
a9ded1e5ce5d75814730bb4caaf49419 Method
We have screened a group of genes that are most likely MSC-specific. Further characterization of the selected genes will be of critical importance in tumorigenesis, progression and prognosis. Murine mesothelioma AB12 and RN5 cells treated with either chemotherapy or γ-ray irradiation in culture, were used to compare gene expression profiles. The selected genes were confirmed by real-time PCR, flow cytometry and immunostaining. In vivo models, peritoneal lavage was collected at different time points after RN5 cell injection, to perform magnetic ranking cytometry with antibody-nanoparticle conjugates, and microarray assay. The expression of Tnfsf18 and Ngfr (CD271) genes associated with prognosis was evaluated in tumor tissues from MPM patients treated with SMART vs pre-SMART protocols, as SMART protocol has already shown significant clinical benefit. Image analysis was performed using Apero Imagescope program.
4c3880bb027f159e801041b1021e88e8 Result
The proportion of MSC significantly increased after RN5 parental cells were treated with either chemotherapy, or γ-ray irradiation, or in combination, while MSC showed more resistance to the above treatments, suggesting that chemoradiation resulted in MSC enrichment. Upregulation of genes Tnfsf18, Serpinb9b, Ly6a (Sca-1), Ngf, and Nppb were confirmed. CD271, the receptor of NGF, was shown to be upregulated after chemoradiation, especially after γ-ray radiation with a dose of 10Gy. Mesothelial precursors captured with magnetic nanoparticles conjugated to anti-Msln and trapped in the microfluidic device in the presence of a magnetic field showed an increase over time from 2-8weeks. Image analysis of human section slides indicated that total positive area of CD271 staining was significantly lower in those who were treated with SMART protocol than those with pre-SMART protocol (p<0.0025). Similar results were obtained in the high, medium and low positive areas from the SMART group, and p values are 0.0013, 0.0017 and 0.0035, respectively, when compared with the pre-SMART group.
8eea62084ca7e541d918e823422bd82e Conclusion
MSC-specific genes like CD271 and Tnfsf18 might be used as potential prognostic indicators and therapeutic targets.
6f8b794f3246b0c1e1780bb4d4d5dc53
