| 英文摘要: | 1645195 - Agrawal
Despite the presence of T-cell mediated antitumor immune mechanism in our body, abnormal cells occasionally elude the immune surveillance, resulting in the onset of cancer. A recently developed antitumor approach, Adoptive Cell Transfer therapy (ACT), utilizes T-cells as "living drugs" by expanding their population outside the body (in vitro) and by enhancing their ability to specifically recognize and destroy tumor cells when reinjected into the body. However, the associated technologies involving genetic modifications and ex vivo proliferation are challenging and impractical for large scale implementation. Furthermore, engineered T-cells often fail to recognize the heterogeneous population of mutated tumor cells commonly found in most cancers. To address these challenges, this project will use a novel approach that bypasses the need for in vitro intervention and induces expansion of cytotoxic T-cell population with enhanced homing capacity and the ability to interact with multiple variants of antigens presented by tumor cells. This will be accomplished by synthesizing specialized packets that will allow targeted expansion and stimulation of the immune cell subpopulation that is cytotoxic to tumor cells. The strategy will significantly simplify the production of T-cells within the body while suppressing toxicity and side effects associated with current immunotherapies. The approach has the potential to utilize the individual's own immune system to treat multiple types of tumors, which will have significant transformative impact. In addition to the medical advancements, the project will serve as a fundamental platform to promote scientific education and development of young scientists. The multidisciplinary nature of the project will provide educational opportunities to graduate and undergraduate students in the areas of micro- and nanotechnology, bioengineering, biochemistry, and cancer biology. Findings from the project will be disseminated among students as well as general population through implementation of results in the coursework and publications in scientific as well as social media.
Current adoptive cell transfer therapies (ACTs) screen tumor cells and tumor infiltrating lymphocytes (TIL) for specific markers and genetically modify autologous T-cells to express the corresponding receptors. While these biomanufactured chimeric antigen receptor presenting T-cells (CAR T-cells) demonstrate high efficacy against a monoclonal population of the antigen presenting tumor cells (APCs), introduction of a single type of antigen specific receptor limits the ability of cytotoxic T cells (CTLs) to interact with different mutated phenotypes commonly found in many tumors. Another significant challenge is the inefficient trafficking of CTLs to the tumor sites. The spiked peripheral CAR T-cells rely on successful infiltration of the tumor lesion before they can be activated upon interaction with APCs, diminishing their effectiveness against solid tumors. Ultimately, the ex vivo expansion of immune cells requires substantial resources and specialized facilities making the existing ACT technologies impractical to implement on a large scale. The project addresses the existing limitations by utilizing liposomes to selectively target the growth and stimulation of autologous CTLs for efficient recognition and cytolysis of tumor cells. Interleukin-2 (IL-2) plays a central role during homeostasis and lymphocyte mediated immune responses and stimulates proliferation as well as functional activity of T-cells. IL-2 also upregulates expression of CXCR3, a unique receptor for tumor associates chemoattractants (e.g. I-TAC), and mediates recruitment of lymphocytes to the site of inflammation (homing) via enhanced endothelial adhesion and transendothelial migration (TEM) across cytokine (TNF-alpha, IFN-gamma) activated endothelial cells. The proposed technique will harness the immunogenic potential of IL-2 providing multiple advantages including: 1) Encapsulation of IL-2 within liposomes will keep the cytokine from degradation, significantly improving its functional activity on T-cells, 2) Conjugation of liposomes with anti-CD8 will allow targeting primarily the cytotoxic T-cell population (CD8+). Thus, the undesired co-stimulation of regulatory T-cells, CD4+ cells and endothelial cells will be suppressed, 3) Enhanced CXCR3 expression will lead to improved infiltration of the tumor tissue by CTLs, 4) Stimulation of a large effector CTL population in vivo with enhanced capability to infiltrate the tumor tissue will reduce the biased surveillance of specific antigens and will likely be more effective in destroying the heterogeneous population of tumor phenotypes that are usually present. The utilization of both liposomes as well as IL-2 is FDA approved and presented T-cell biomanufacturing approach will have a considerable transformative impact on tumor therapies. Since the targeted CD8+ T-cell amplification can be induced in vivo, the technique has the potential for a more universal approach against various tumors and infections, greatly impacting the society. The multidisciplinary project, integrating bioengineering, biochemistry, cell biology, and microfabrication, will support the new Bioengineering PhD program at George Mason University offering an excellent opportunity for training in STEM education by involving PhD and undergraduate students. Particular emphasis will be given on the recruitment of underrepresented groups including females and minority students. Findings from the project will also be implemented in the coursework to stimulate student awareness on current scientific developments. Additionally, project outcomes will be disseminated within the scientific community and general population through journal publications and postings in the social media platforms such as YouTube videos as well as laboratory group webpage. |