Development of Artificial Membrane Binding Proteins for the Enhancement of Adoptive Cell Therapies

Adoptive cell therapies (ACT) are rapidly emerging as an exciting new therapeutic modality in medical oncology, due to their novel mechanisms of action that potentially overcome drug resistance and produce durable remissions ^1–3; these therapies aim to redirect the patient's own immune system to selectively target cancer cells. While ACT have shown great success for the treatment of hematologic malignancies such as Acute Lymphoblastic Leukemias (ALL) or Non- Hodgkin Lymphomas, response rates among patients with solid cancers are less favorable. The lack of widespread treatments for solid tumors, which accounts for 85% of all tumor deaths, stems from the inability of immune cells to effectively home to the tumor site and penetrate the tumor microenvironment. Moreover, a hypoxic and suppressive tumor extracellular matrix can inhibit cytotoxic T-cells’ ability to expand, persist and mediate cytotoxicity through the presentation of immunosuppressive modulators. Accordingly, the aim of this research project is to develop artificial membrane-binding proteins (AMBP) to improve the performance of adoptive cell therapies in solid tumors. AMBPs are designer proteins that have been modified to spontaneously insert into the membrane of cells, without penetrating into the cytoplasm. This approach allows the rapid display of functional proteins or peptides on the surface of T-cells, which can provide homing, adhesion, immune regulation, and hypoxia resistance to the donor cell, without affecting their function or viability^4,5. In this work, an AMBP is designed, expressed, purified, and characterized using SDS-PAGE, matrix-assisted laser desorption/ionization time-of- flight mass spectrometry (MALDI-TOF MS) and several biophysical techniques such as Circular Dichroism, UV-Vis spectroscopy and Dynamic Light Scattering. In addition, to demonstrate the improved effectiveness of antigen-specific T-cells coated with AMBPs in controlling tumor growth, <i>in vitro</i> functional assays such as Cell Viability and Cytotoxicity, Proliferation and Activation and Killing assays, will be done.<br/>References:<br/>1. Brentjens, R. J. <i>et al.</i> CD19-targeted T cells rapidly induce molecular remissions in adults with chemotherapy-refractory acute lymphoblastic leukemia. <i>Science translational medicine</i> <b>5</b>, 177ra38 (2013).<br/>2. Maude, S. L. <i>et al.</i> Chimeric antigen receptor T cells for sustained remissions in leukemia. <i>The New England journal of medicine</i> <b>371</b>, 1507–1517 (2014).<br/>3. Besser, M. J. <i>et al.</i> Adoptive transfer of tumor-infiltrating lymphocytes in patients with metastatic melanoma: Intent-to-treat analysis and efficacy after failure to prior immunotherapies. <i>Clinical Cancer Research</i> <b>19</b>, 4792–4800 (2013).<br/>4. Xiao, W. <i>et al.</i> Designer artificial membrane binding proteins to direct stem cells to the myocardium. <i>Chemical Science</i> <b>10</b>, 7610–7618 (2019).<br/>5. Armstrong, J. P. K. <i>et al.</i> Artificial membrane-binding proteins stimulate oxygenation of stem cells during engineering of large cartilage tissue. <i>Nature Communications</i> <b>6</b>, (2015).