Selective refueling of CAR T cells using ADA1 and CD26 boosts antitumor immunity.

Chimeric antigen receptor (CAR) T cell therapy is hindered in solid tumor treatment due to the immunosuppressive tumor microenvironment and suboptimal T cell persistence. Current strategies do not address nutrient competition in the microenvironment. Hence, we present a metabolic refueling approach using inosine as an alternative fuel. CAR T cells were engineered to express membrane-bound CD26 and cytoplasmic adenosine deaminase 1 (ADA1), converting adenosine to inosine. Autocrine secretion of ADA1 upon CD3/CD26 stimulation activates CAR T cells, improving migration and resistance to transforming growth factor ß1 suppression. Fusion of ADA1 with anti-CD3 scFv further boosts inosine production and minimizes tumor cell feeding. In mouse models of hepatocellular carcinoma and non-small cell lung cancer, metabolically refueled CAR T cells exhibit superior tumor reduction compared to unmodified CAR T cells. Overall, our study highlights the potential of selective inosine refueling to enhance CAR T therapy efficacy against solid tumors.

Neural stem cells genetically-modified to express neprilysin reduce pathology in Alzheimer transgenic models.

INTRODUCTION: Short-term neural stem cell (NSC) transplantation improves cognition in Alzheimer's disease (AD) transgenic mice by enhancing endogenous synaptic connectivity. However, this approach has no effect on the underlying beta-amyloid (Aß) and neurofibrillary tangle pathology. Long term efficacy of cell based approaches may therefore require combinatorial approaches. METHODS: To begin to examine this question we genetically-modified NSCs to stably express and secrete the Aß-degrading enzyme, neprilysin (sNEP). Next, we studied the effects of sNEP expression in vitro by quantifying Aß-degrading activity, NSC multipotency markers, and Aß-induced toxicity. To determine whether sNEP-expressing NSCs can also modulate AD-pathogenesis in vivo, control-modified and sNEP-NSCs were transplanted unilaterally into the hippocampus of two independent and well characterized transgenic models of AD: 3xTg-AD and Thy1-APP mice. After three months, stem cell engraftment, neprilysin expression, and AD pathology were examined. RESULTS: Our findings reveal that stem cell-mediated delivery of NEP provides marked and significant reductions in Aß pathology and increases synaptic density in both 3xTg-AD and Thy1-APP transgenic mice. Remarkably, Aß plaque loads are reduced not only in the hippocampus and subiculum adjacent to engrafted NSCs, but also within the amygdala and medial septum, areas that receive afferent projections from the engrafted region. CONCLUSIONS: Taken together, our data suggest that genetically-modified NSCs could provide a powerful combinatorial approach to not only enhance synaptic plasticity but to also target and modify underlying Alzheimer's disease pathology.

Clinical performance metrics of 3D digital breast tomosynthesis compared with 2D digital mammography for breast cancer screening in community practice.

OBJECTIVE: The objective of our study was to assess the clinical performance of combined 2D-3D digital breast tomosynthesis (DBT), referred to as "3D DBT," compared with 2D digital mammography (DM) alone for screening mammography in a community-based radiology practice. MATERIALS AND METHODS: Performance outcomes measures were assessed for 14 radiologists who interpreted more than 500 screening mammography 3D DBT studies after the initiation of tomosynthesis. Outcomes from screening mammography during the study period between August 9, 2011, and November 30, 2012, using 3D DBT (n = 23,149 patients) versus 2D DM (n = 54,684 patients) were compared. RESULTS: For patients screened with 3D DBT, the relative change in recall rate was 16.1% lower than for patients screened with 2D DM (p > 0.0001). The overall cancer detection rate (CDR), expressed as number of cancers per 1000 patients screened, was 28.6% greater (p = 0.035) for 3D DBT (6.3/1000) compared with 2D DM (4.9/1000). The CDR for invasive cancers with 3D DBT (4.6/1000) was 43.8% higher (p = 0.0056) than with 2D DM (3.2/1000). The positive predictive value for recalls from screening (PPV1) was 53.3% greater (p = 0.0003) for 3D DBT (4.6%) compared with 2D DM (3.0%). No significant difference in the positive predictive value for biopsy (PPV3) was found for 3D DBT versus 2D DM (22.8% and 23.8%, respectively) (p = 0.696). CONCLUSION: In community-based radiology practice, mammography screening with 3D DBT yielded lower recall rates, an increased CDR for cancer overall, and an increased CDR for invasive cancer compared with 2D DM. The PPV1 was significantly greater in the group screened using 3D DBT.

Roles of spleen and liver in development of the murine hematopoietic system.

OBJECTIVE: Hematopoietic stem cells (HSCs) and colony-forming progenitor cells (CFCs) are believed to migrate from liver to bone marrow (BM) around the time of birth, where they remain throughout the animal's life. Although in mice the spleen is also a hematopoietic organ, neither the origin nor the contribution of spleen HSCs to hematopoietic homeostasis has been assessed relative to that of BM HSCs. To investigate these issues we quantitated CFC and HSC activity in the spleen, BM, peripheral blood, and liver of the mouse during ontogeny. METHODS: CFCs were assessed by clonogenic colony formation, and HSCs by long-term reconstituting ability. RESULTS: CFCs gradually increased in the BM and decreased in the liver with age. Increased prevalence of CFCs in fetal and pup blood occurred at day (d) 12 postcoitus (pc) and during the period of d16 pc to 4d postbirth, corresponding to the times when hematopoietic cells migrate from the yolk sac and/or aorta-gonad-mesonephros (AGM) to the fetal liver and from the neonatal liver to the BM, respectively. In the spleen, CFCs displayed two peaks of activity at 2d and 14d-15d postbirth. Spleen HSCs also fluctuated during this time period. Neonatal splenectomy did not alter CFC or HSC frequencies in the BM, but CFCs increased in the livers of splenectomized mice. CONCLUSIONS: These data demonstrate that the liver may act as a site of extramedullary hematopoiesis in the neonate, especially in the absence of the spleen, and imply that the spleen, BM, and liver cooperatively contribute to hematopoietic homeostasis.