Targeting monoamine oxidase A for T cell-based cancer immunotherapy

Monoamine oxidase A (MAO-A) is an enzyme best known for its function in the brain, where it breaks down neurotransmitters and thereby influences mood and behavior. Small-molecule MAO inhibitors (MAOIs) have been developed and are clinically used for treating depression and other neurological disorders. However, the involvement of MAO-A in antitumor immunity has not been reported. Here, we observed induction of the Maoa gene in tumor-infiltrating immune cells. Maoa knockout mice exhibited enhanced antitumor T cell immunity and suppressed tumor growth. MAOI treatment significantly suppressed tumor growth in preclinical mouse syngeneic and human xenograft tumor models in a T cell-dependent manner. Combining MAOI and anti-PD-1 treatments generated synergistic tumor suppression effects. Clinical data correlation studies associated intratumoral MAOA expression with T cell dysfunction and decreased patient survival in a broad range of cancers. We further demonstrated that MAO-A restrains antitumor T cell immunity through controlling intratumoral T cell autocrine serotonin signaling. Together, these data identify MAO-A as an immune checkpoint and support repurposing MAOI antidepressants for cancer immunotherapy.

Psoriasis drugs in the medicare population: dermatologists' spending and prescription patterns

PURPOSE

Over the past decade, many new biologic and small-molecule drugs have been approved for psoriasis. These specialty drugs tend to be expensive and place financial burden on the healthcare system as well as patients. This study aims to explore trends in Medicare Part D spending and prescription patterns for psoriasis drugs by dermatologists.

METHODS

The Centers for Medicare and Medicaid Services' (CMS) Medicare Part D Public Use Files from 2013 to 2017 were utilized to examine prescription rates and pricing FDA-approved psoriasis drugs.

RESULTS

From 2013 to 2017, psoriasis drugs accounted for 41% of total Medicare Part D spending by dermatologists in the database, of which biologics accounted for 86.5%. The proportion of psoriasis-related spending increased from 36% of total spending in 2013 to 53% in 2017. Prescriptions of etanercept decreased while prescribers of newly approved drugs increased significantly. The cost per day of biologics were significantly variable in 2013 but converged toward similar costs in 2017.

CONCLUSION

Psoriasis prescriptions comprise a large, increasing proportion of Medicare Part D spending related to dermatology. These increasing costs have significant implications for the healthcare system and affect out-of-pocket costs for patients who rely on such medications.

Development of Hematopoietic Stem Cell-Engineered Invariant Natural Killer T Cell Therapy for Cancer

Invariant natural killer T (iNKT) cells are potent immune cells for targeting cancer; however, their clinical application has been hindered by their low numbers in cancer patients. Here, we developed a proof-of-concept for hematopoietic stem cell-engineered iNKT (HSC-iNKT) cell therapy with the potential to provide therapeutic levels of iNKT cells for a patient's lifetime. Using a human HSC engrafted mouse model and a human iNKT TCR gene engineering approach, we demonstrated the efficient and long-term generation of HSC-iNKT cells in vivo. These HSC-iNKT cells closely resembled endogenous human iNKT cells, could deploy multiple mechanisms to attack tumor cells, and effectively suppressed tumor growth in vivo in multiple human tumor xenograft mouse models. Preclinical safety studies showed no toxicity or tumorigenicity of the HSC-iNKT cell therapy. Collectively, these results demonstrated the feasibility, safety, and cancer therapy potential of the proposed HSC-iNKT cell therapy and laid a foundation for future clinical development.

miR-146a modulates autoreactive Th17 cell differentiation and regulates organ-specific autoimmunity

Autoreactive CD4 T cells that differentiate into pathogenic Th17 cells can trigger autoimmune diseases. Therefore, investigating the regulatory network that modulates Th17 differentiation may yield important therapeutic insights. miR-146a has emerged as a critical modulator of immune reactions, but its role in regulating autoreactive Th17 cells and organ-specific autoimmunity remains largely unknown. Here, we have reported that miR-146a-deficient mice developed more severe experimental autoimmune encephalomyelitis (EAE), an animal model of human multiple sclerosis (MS). We bred miR-146a-deficient mice with 2D2 T cell receptor-Tg mice to generate 2D2 CD4 T cells that are deficient in miR-146a and specific for myelin oligodendrocyte glycoprotein (MOG), an autoantigen in the EAE model. miR-146a-deficient 2D2 T cells induced more severe EAE and were more prone to differentiate into Th17 cells. Microarray analysis revealed enhancements in IL-6- and IL-21-induced Th17 differentiation pathways in these T cells. Further study showed that miR-146a inhibited the production of autocrine IL-6 and IL-21 in 2D2 T cells, which in turn reduced their Th17 differentiation. Thus, our study identifies miR-146a as an important molecular brake that blocks the autocrine IL-6- and IL-21-induced Th17 differentiation pathways in autoreactive CD4 T cells, highlighting its potential as a therapeutic target for treating autoimmune diseases.

Propagating Humanized BLT Mice for the Study of Human Immunology and Immunotherapy

The humanized BLT (bone marrow-liver-thymus) mouse model harbors a nearly complete human immune system, therefore providing a powerful tool to study human immunology and immunotherapy. However, its application is greatly limited by the restricted supply of human CD34+ hematopoietic stem cells and fetal thymus tissues that are needed to generate these mice. The restriction is especially significant for the study of human immune systems with special genetic traits, such as certain HLA (human leukocyte antigen) haplotypes or monogene deficiencies. In order to circumvent this critical limitation, we have developed a method to quickly propagate established BLT mice. Through secondary transfer of bone marrow cells and human thymus implants from BLT mice into NSG (NOD/SCID/IL-2Rγ−/−) recipient mice, we were able to expand one primary BLT mouse into a colony of 4–5 proBLT (propagated BLT) mice in 6–8 weeks. These proBLT mice reconstituted human immune cells, including T cells, at levels comparable to that of their primary BLT donor mouse. They also faithfully inherited the human immune cell genetic traits from their donor BLT mouse, such as the HLA-A2 haplotype that is of special interest for studying HLA-A2 restricted human T cell immunotherapies. Moreover, an EGFP reporter gene engineered into the human immune system was stably passed from BLT to proBLT mice, making proBLT mice suitable for studying human immune cell gene therapy. This method provides an opportunity to overcome a critical hurdle to utilizing the BLT humanized mouse model and enables its more widespread use as a valuable pre-clinical research tool.

Propagating Humanized BLT Mice for the Study of Human Immunology and Immunotherapy

The humanized bone marrow-liver-thymus (BLT) mouse model harbors a nearly complete human immune system, therefore providing a powerful tool to study human immunology and immunotherapy. However, its application is greatly limited by the restricted supply of human CD34⁺ hematopoietic stem cells and fetal thymus tissues that are needed to generate these mice. The restriction is especially significant for the study of human immune systems with special genetic traits, such as certain human leukocyte antigen (HLA) haplotypes or monogene deficiencies. To circumvent this critical limitation, we have developed a method to quickly propagate established BLT mice. Through secondary transfer of bone marrow cells and human thymus implants from BLT mice into NSG (NOD/SCID/IL-2Rγ^-/-) recipient mice, we were able to expand one primary BLT mouse into a colony of 4-5 proBLT (propagated BLT) mice in 6-8 weeks. These proBLT mice reconstituted human immune cells, including T cells, at levels comparable to those of their primary BLT donor mouse. They also faithfully inherited the human immune cell genetic traits from their donor BLT mouse, such as the HLA-A2 haplotype that is of special interest for studying HLA-A2-restricted human T cell immunotherapies. Moreover, an EGFP reporter gene engineered into the human immune system was stably passed from BLT to proBLT mice, making proBLT mice suitable for studying human immune cell gene therapy. This method provides an opportunity to overcome a critical hurdle to utilizing the BLT humanized mouse model and enables its more widespread use as a valuable preclinical research tool.

Probing the mechanisms of drug release from hydroxypropylmethyl cellulose matrices

The transient dynamic swelling and dissolution behavior during drug release from hydroxypropylmethyl cellulose (HPMC) matrices was investigated using fluorescein as a model drug. A new flow-through cell capable of providing a well-defined hydrodynamic condition and a non-destructive mode of operation was designed for this purpose to assess the associated moving front kinetics. The results obtained show a continuous increase in transient gel layer thickness irrespective of the polymer viscosity grade or drug loading. This is attributed to the faster rate of swelling solvent penetration than that of polymer dissolution under the present experimental condition. On the other hand, the observed shrinkage of sample diameter over a longer time period demonstrates that polymer dissolution does indeed occur in HPMC matrices. Further, both the rates of polymer swelling and dissolution as well as the corresponding rate of drug release increase with either higher levels of drug loading or lower viscosity grades of HPMC. For water-soluble drugs, the present results suggest that the effect of HPMC dissolution on drug release is insignificant and the release kinetics are mostly regulated by a swelling-controlled diffusional process, particularly for higher viscosity grades of HPMC.