Lymphocyte effector crosstalk in inflamed tumor microenvironment, Bioengineered agents for cancer immunotherapy, Immunoscore signature for cancer health disparity, Neuro-immune interaction, Neuroimmunotherapy
After receiving a PhD in tumor immunology in 1999 from Banaras Hindu University, India, Dr. Anil Shanker performed his postdoctoral studies at the CNRS/INSERM Centre d’Immunologie de Marseille-Luminy, France, and the National Cancer Institute, Maryland. He currently leads the Laboratory of Lymphocyte Function in the Department of Biochemistry and Cancer Biology of Meharry Medical College. He is also a member of Vanderbilt-Ingram Cancer Center of Vanderbilt University.
The Shanker laboratory has a history of providing vibrant environment to his trainees, postdoctoral fellows and junior faculty from diverse backgrounds. Dr. Shanker is committed to advancing equity in health and education that empowers the underprivileged. He has conceived of and implemented transdisciplinary research directions by integrating tumor biology, immunology, bioengineering, computational biology, neuroscience and immunotherapy. The Shanker Laboratory explores lymphocyte crosstalk with an aim to understand molecular and cellular players driving immune effector responses. Our ultimate goal is to develop a comprehensive understanding of the circuitry underlying lymphocyte crosstalk with an aim to control immunopathological diseases. The ongoing themes of our research studies are:
Molecular circuitry underlying T–NK cell crosstalk: In response to a cancer-germline self-antigen P1A, akin to human MAGE-like antigens, our pioneering studies using TCR-P1A transgenic mice (J Immunol 172:5069) established normal thymic development of CD8 T cells and discovered a paradigm of CD8 T cell help for innate NK effector function in solid tumor microenvironments. Such a potentiated CD8 T–NK crosstalk enhances immunosurveillance against tumor development and prevents tumor escape (J Immunol 179:6377). This correlates to humans where tumor-infiltrating lymphocytes from post-surgery relapse-free breast cancer patients show signatures of NK cell activation (J Transl Med 11:145). Ongoing work has identified mitochondrial Ca2+ transport-dependent intermembranous interaction critical for CD8 T–NK effector cooperativity. We also dissected the biological relevance of perforin-dependent granule exocytosis and death receptor/ligand-mediated cytolytic mechanisms of lymphocytes. We found that CD8 T cells preferentially use death ligands and NK cells NKG2D to inhibit metastasis of tumor cells that express low-avidity antigens (J Immunol 177:2575; Cancer Res 69:6615; Immunol 121:41). We are capitalizing on these findings to develop efficient adoptive cell immunotherapy protocols.
Combining bortezomib or small-molecule natural product chemotherapeutic agents with adoptive cell immunotherapy in solid tumors: We were the first to show that administration of bortezomib, a proteasome inhibitor, in mice bearing mammary and renal tumors sensitized tumor cells to apoptosis by amplifying tumor cell caspase-8 activation following treatment with TRAIL receptor agonist antibody (JNCI 100:649). Similar effects of bortezomib were observed on human renal cancer cells (Mol Cancer Res 8:729). We identified novel immunostimulatory effects of bortezomib on lymphocyte effector functions (Oncotarget 8:8604). Data demonstrate that bortezomib treatment given at a dose of 1 mg/kg b.w. (<20 nM) into mice does not induce cell death in lymphoid or myeloid cells, nor does it affect antigen presentation or proliferation of antigen-specific CD4 or CD8 T cells (Cancer Res 75:5260). Rather, bortezomib treatment improves antitumor lymphocyte function by upregulating/stabilizing Notch, NFkB and TCR signaling by inducing miR-155-mediated downregulation of SOCS1 and SHIP1 (Oncotarget 6:32439; Front Immunol 12:607044). Recently, screening for sensitizers of cancer cells to TRAIL-mediated apoptosis identified a natural product of the 17β-hydroxywithanolide (17- BHW) class, physachenolide C (PCC), as a promising hit. PCC enhanced tumor cell death in response to activated T cells, both in vitro and in vivo, in a death-ligand dependent manner. These results offer a preclinical proof for combining bortezomib or PCC with lymphocyte transfers to improve the outcomes of cancer immunotherapy.
Bioengineering Notch ligand constructs and controlled-release immune checkpoint inhibitors for cancer immunotherapy and building a prognostic Notch-based immunoscore signature for cancer health disparities: In lung cancer patients, we identified a novel pathological axis of Notch signaling accentuating tumor immunosuppression (Cancer Res 71:6122). We engineered novel multivalent and monovalent Notch Delta-like and Jagged ligand constructs that promote T cell effector and memory functions, thereby overcoming the immunosuppressive tumor microenvironment (Cancer Res 75:4728; JITC 7:95). Using breast, kidney and inducible EGFR-mutant lung cancer mouse models, with human correlative studies in NSCLC patients, we are optimizing adoptive cell therapy of CD8 T and NK cells in combination with engineered immunostimulatory Notch ligands. We are developing controlled release immune checkpoint inhibitors for testing in ovarian cancer models. We are also performing analysis of Notch signaling and associated metabolic, effector and memory markers in tumor-infiltrating lymphocytes of preclinical murine models and NSCLC patient samples. The findings of the ongoing studies will help improve cancer immunotherapy approaches and identify differences in minority populations to provide insights on the immunologic basis of cancer health disparities.
Neuro-immune interaction in lymphocyte function: Immune cells rely on cell-cell communication to specify their responses. During a crosstalk between the nervous system and the immune system, intercellular communication and the downstream signal transduction events are influenced by neurotransmitters present in the local tissue environments in an autocrine or paracrine fashion. We were intrigued by the expression of various neurotransmitter receptors on T cells. In addition, immune cells send signals to the brain through cytokines, and are present in the brain to influence neural responses. Altered communication between the nervous and immune systems is emerging as a common feature in neurodegenerative and immunopathological diseases. We are exploring the mechanistic frameworks of immunostimulatory and immunosuppressive effects neurotransmitters exert on lymphocytes and non-lymphoid immune cells. Identification of underlying mechanisms will provide insights on the role neuroimmune crosstalk plays in the pathogenesis of cancer and various neurodegenerative disorders, including Alzheimer’s disease (J Blood Lymph 1:1; Front Immunol 10:3389).
Modeling of lymphocyte network: We are integrating immunology, biophysics and computational biology to understand the fundamental details of lymphocyte functions. We are testing a model whereby input signals determined by Ca2+ flux between mitochondria, endoplasmic reticulum and cytoplasm form a biosensor module of a cellular proportional–integral–derivative (PID) controller to compute output signals that guide cell fate and lymphocyte network output (Antioxid Redox Signaling 20: 1533; Open Biol 6:160192; Aging 9:627; Front Immunol 10:1906).