Quantitative in Vivo Imaging of Immune Response to SYMPHONY Using a Murine Window Chamber Model

Palmer, Gregory M

Yang, Jinming

2023-06-08T18:34:42Z

2023

Medical Physics DKU

Bladder cancer is a malignant tumor that develops on the mucosa of the bladder. It is one of the top ten occurring cancers in the body and one of the top ten malignant tumors in the urinary system. Non-muscle invasive bladder cancer is the most common type of bladder cancer, accounting for approximately 70% of all patients with bladder cancer. Typically, for patients who are detected to have muscle-invasive bladder cancer, the hope of cure is less than for patients who have non-muscle-invasive bladder cancer. Nowadays, chemotherapy based on cisplatin is the most common treatment for metastatic bladder cancer. However, only about half of bladder cancer patients are suitable for chemotherapy, and its efficacy ranges from 40% to 65%. Immunotherapy, which reactivates the inhibitory function of immune cells by blocking immunological checkpoints for the aim of treating cancer, is the most generally considered alternative to chemotherapy at present. Immune activation using BCG has also been proposed as a viable treatment for bladder cancer. Yet, these are insufficient to prove effective against metastatic cancers. SYnergistic iMmuno PHOtothermal NanotherapY, called SYMPHONY, refers to the combination of immunotherapy and gold nanostar-mediated photothermal therapy for primary tumor. Gold nanostar-mediated photothermal therapy is the use of a wavelength of 1064 nm laser irradiation for about 10 minutes in the mouse flank tumor location, and its treatment is local. Unlike photothermal treatment, the immune response induced by anti-PD-L1 injection is systemic. We believe that this therapy can enhance the clinical treatment of bladder cancer with metastasis. In previous investigations, C57BL/6 mice were injected at two locations with MB49 bladder cancer cells, but only one location received local laser treatment with 1064 nm wavelength. Tumor volume over time was recorded. One of the five SYMPHONY mice was able to suppress the tumor following treatment, however, the other groups were unable to reach the same outcome. When the same tumor cells were utilized to challenge the mice a second time, the tumor exhibited no symptoms of development, demonstrating a long-term immunity has occurred. The cure for metastatic bladder cancer is related to the development of an immune memory response, as this concept has been prooven. Yet, there is still little known about quantification of the immune response at the distant tumor location after treatment. Our long-term goal is to develop an effective alternative treatment for patients with metastatic bladder cancer. The overall objective of this application is to quantify the immune responses of transgenic mice with fluorescent report genes on myeloid cells (monocytes, macrophages, natural killer cells, dendritic cells), and T cells undergoing one of four treatments (no treatment (control), nano-photothermal therapy (GNS), immunotherapy (anti-PD-L1), SYMPHONY)), and the time point for additional research within the week after treatment was determined. Our central hypothesis is that transgenic mice treated with SYMPHONY would show higher immune cell infiltration in distant tumors within 48 hours after treatment, and symphony-induced immune response in distant tumors would be stronger than antipdl1 alone. This hypothesis was tested by implanting a primary flank tumor and an untreated small distant tumor in 20 mice. The distant tumor cells were stained with DiD red fluorescent dye and then injected into the center of a dorsal skinfold window chamber. The dorsal skinfold window chamber is on the skin of the back of the mouse sutured by surgery for imaging. The primary tumors received one of the four treatments and were imaged using intravital microscope over the 7 days after treatment. From this study, we found that the immune signal of macrophages in the SYMPHONY treatment group peaked on the third day of treatment and then decreased continuously, which was consistent with the change trend of the window chamber tumor area. Secondly, and the primary tumor volume and distant window chamber tumor area decreased within seven days of SYMPHONY treatment group. This is supportive of our hypothesis and previously published work. Future research should concentrate on the immunological response of mice on the day of treatment, monitor the changes in multiple immune cells, and quantify the effects of laser treatment on this day. Notably, the use of immune signals around distant tumor to predict immune response within tumor requires imaging at intervals more frequently than every 24 hours, because estimating the rate of macrophage movement in tissues, where the more appropriate imaging frequency is every 2 hours.

https://hdl.handle.net/10161/27877

Medicine

Quantitative in Vivo Imaging of Immune Response to SYMPHONY Using a Murine Window Chamber Model

Master's thesis

24

2025-05-25T00:00:00Z