Recurrent pancreatic cancer treated with N-803 and PD-L1 t-haNK followed by an EGFR-targeted nanocell drug conjugate.

Multimodal temporal therapy orchestrated to leverage immunotherapy, tumor-targeted chemotherapy, and natural killer (NK) cell therapy may provide an opportunity to induce immunogenic cell death for tumor response and increased survival in patients with recurrent cancer. The interleukin-15 (IL-15) superagonist N-803, an enhancer of NK cells, CD4 + T cells, cytotoxic CD8 + T cells, and memory T-cell activity, combined with off-the-shelf PD-L1-targeted high-affinity NK (PD-L1 t-haNK) cells represent novel immunotherapies designed to overcome an immunosuppressive tumor microenvironment (TME). The epidermal growth factor receptor-targeted antibody-nanocell conjugate E-EDV-D682 provides tumor-targeted chemotherapy in the form of its anthracycline metabolite PNU159682 (nemorubicin) cargo and is currently being studied in combination with immunomodulatory EDVs delivering the adjuvant α-galactosyl ceramide (GC). Here, we report the compassionate use treatment of this combination in a patient with recurrent, metastatic pancreatic cancer (mPC) after 3 lines of therapy. Under the initial single-patient Investigational New Drug (spIND) protocol, the patient received N-803, PD-L1 t-haNK cells, and the albumin doxorubicin conjugate aldoxorubicin for ~27 months. The patient's disease became stable on this regimen, and a transient complete response was observed by ~14 months of therapy. Due to progression, a second spIND protocol was designed whereby the patient received E-EDV-D682 plus EDV-GC for more than 24 months, which resulted in stable disease and the patient's continued survival at the time this report was written. The patient's extended survival despite the dire prognosis associated with recurrent mPC points to the merits of this temporal combination regimen in overcoming immuno-chemo resistance with enhanced immune activity required for tumor response and extended survival.

N-803 Plus BCG Treatment for BCG-Naïve or -Unresponsive Non-Muscle Invasive Bladder Cancer: A Plain Language Review.

WHAT IS THIS SUMMARY ABOUT?: This is a summary of two studies that looked at the safety and effectiveness of a potential new treatment, N-803 (Anktiva), in combination with a standard treatment bacillus Calmette-Guerin (BCG) for people with non-muscle invasive bladder cancer (NMIBC).One study was a Phase 1b study that tested increasing doses of N-803 in combination with the same dose of BCG in people with NMIBC who had never received BCG previously (BCG-naive). The other study is a Phase 2/3 study of N-803 and BCG in people with NMIBC whose cancer wasn't eliminated by BCG alone (BCGunresponsive). WHAT HAPPENED IN THE STUDIES?: In the Phase 1b study, the nine participants were split into three groups of 3 participants who received a dose of 100, 200, or 400 µg N-803 along with a standard 50 mg dose of BCG. In the Phase 2/3 study, one group (cohort A) of participants with carcinoma in situ (CIS) disease and another group (cohort B) with papillary disease were treated with 400 µg N-803 plus 50 mg BCG. There was also a cohort C that received only 400 µg N-803. Treatments were delivered directly into the bladder once a week for 6 weeks in a row. WHAT WERE THE KEY TAKEAWAYS?: N-803 plus BCG eliminated NMIBC in all nine BCG-naive participants and the effects were long-lasting, with participants remaining NMIBC-free for a range of 8.3 to 9.2 years.As reported in 2022, cancer was eliminated in 58 of 82 (71%) participants with BCG-unresponsive CIS disease and the effect was also long-lasting. Importantly, approximately 90% of the successfully treated participants avoided surgical removal of the bladder. In cohort B participants with papillary disease, 40 of 72 (55.4%) were cancer-free 12 months after treatment. N-803 used alone was only effective in 2 of 10 participants. In both studies, the combination of N-803 and BCG was found to be associated with very few adverse events.Based on results from the Phase 2/3 study, the U.S. Food and Drug Association (FDA) approved the use of N-803 plus BCG for the treatment of BCG-unresponsive bladder CIS with or without Ta/T1 papillary disease.Clinical Trial Registration: NCT02138734 (Phase 1b study), NCT03022825 (Phase 2/3 study).

Addition of the IL-15 superagonist N-803 to BCG therapy produces a high rate of success in eliminating non-muscle invasive bladder cancer in both BCG-naive and BCG-unresponsive patients, with long-lasting effects that allow patients to avoid surgical removal of the bladder.

Quality of Life in the Phase 2/3 Trial of N-803 Plus Bacillus Calmette-Guérin in Bacillus Calmette-Guérin‒Unresponsive Nonmuscle-Invasive Bladder Cancer.

INTRODUCTION: In the phase 2/3 study QUILT-3.032 (NCT03022825), the ability of the IL-15RαFc superagonist N-803 (nogapendekin alfa inbakicept) plus bacillus Calmette-Guérin (BCG) to elicit durable complete responses in patients with BCG-unresponsive nonmuscle-invasive bladder cancer (NMIBC) was demonstrated. As a secondary end point, patient-reported outcomes (PROs) were assessed. METHODS: Both cohort A patients with carcinoma in situ with or without Ta/T1 disease and cohort B patients with high-grade Ta/T1 papillary disease who received N-803 plus BCG therapy completed the EORTC (European Organization for Research and Treatment of Cancer) Core 30 and Quality of Life NMIBC-Specific 24 questionnaires at baseline and months 6, 12, 18, and 24 on study. Scores were analyzed using descriptive statistics, and multivariable analyses were performed to identify baseline variables associated with PROs. RESULTS: On study, mean physical function (PF) and global health (GH) scores remained relatively stable from baseline for cohorts A (n = 86) and B (n = 78). At month 6, cohort A patients with a complete response reported higher PF scores than those without (P = .0659); at month 12, > 3 as compared with ≤ 3 prior transurethral resections of bladder tumor was associated (P = .0729) with lower GH scores. In cohort B, baseline disease type was associated (P = .0738) with PF and race was significantly associated (P = .0478) with GH at month 6. NMIBC-Specific 24 summary scores also remained stable on study for both cohorts. CONCLUSIONS: The overall stability of PROs scores, taken together with the efficacy findings, indicates a favorable risk-benefit ratio and quality of life following N-803 plus BCG.

Inferred Immune-Cell Activity Is an Independent Predictor of HER2-Negative Breast Cancer Prognosis and Response to Paclitaxel-Based Therapy in the GeparSepto Trial.

PURPOSE: Tumor microenvironment (TME) immune markers have been correlated with both response to neoadjuvant therapy and prognosis in patients with breast cancer. Here, immune-cell activity of breast cancer tumors was inferred by expression-based analysis to determine if it is prognostic and/or predictive of response to neoadjuvant paclitaxel-based therapy in the GeparSepto (G7) trial (NCT01583426). EXPERIMENTAL DESIGN: Pre-study biopsies from 279 patients with HER2-negative breast cancer in the G7 trial underwent RNA-seq-based profiling of 104 immune-cell-specific genes to assess inferred Immune Cell Activity (iICA) of 23 immune-cell types. Hierarchical clustering was used to classify tumors as iICA "hot," "warm," or "cold" by comparison of iICA in the G7 cohort relative to that of 1,467 samples from a tumor database established by Nantomics LLC. Correlations between iICA cluster, pathology-assessed tumor-infiltrating lymphocytes (TIL), and hormone receptor (HR) status for pathologic complete response (pCR), disease-free survival (DFS), and overall survival (OS) were determined. RESULTS: iICA cluster correlated with TIL levels. The highest pCR rates were observed in hot cluster tumors, and those with relatively higher TILs. Greater inferred activity of several T-cell types was significantly associated with pCR and survival. DFS and OS were prolonged in patients with hot or warm cluster tumors, the latter particularly for HR negative tumors, even if TILs were relatively low. CONCLUSIONS: Overall, TIL level better predicted pCR, but iICA cluster better predicted survival. Differences in associations between TILs, cluster, pCR, and survival were observed for HR-positive tumors versus HR-negative tumors, suggesting expanded study of the implication of these findings is warranted.

IL-15 Superagonist NAI in BCG-Unresponsive Non-Muscle-Invasive Bladder Cancer.

BACKGROUND: Patients with Bacillus Calmette­Guérin (BCG)­unresponsive non­muscle-invasive bladder cancer (NMIBC) have limited treatment options. The immune cell­activating interleukin-15 (IL-15) superagonist Nogapendekin alfa inbakicept (NAI), also known as N-803, may act synergistically with BCG to elicit durable complete responses (CRs) in this patient population. METHODS: In this open-label, multicenter study, patients with BCG-unresponsive bladder carcinoma in situ (CIS) with or without Ta/T1 papillary disease were treated with intravesical NAI plus BCG (cohort A) or NAI alone (cohort C). Patients with BCG-unresponsive high-grade Ta/T1 papillary NMIBC also received NAI plus BCG (cohort B). The primary end point was the incidence of CR at the 3- or 6-month assessment visit for cohorts A and C, and the disease-free survival (DFS) rate at 12 months for cohort B. Durability, cystectomy avoidance, progression-free survival, disease-specific survival (DSS), and overall survival were secondary end points for cohort A. RESULTS: In cohort A, CR was achieved in 58 (71%) of 82 patients (95% confidence interval [CI]=59.6 to 80.3; median follow-up, 23.9 months), with a median duration of 26.6 months (95% CI=9.9 months to [upper bound not reached]). At 24 months in patients with CR, the Kaplan­Meier estimated probability of avoiding cystectomy and of DSS was 89.2% and 100%, respectively. In cohort B (n=72), the Kaplan­Meier estimated DFS rate was 55.4% (95% CI=42.0% to 66.8%) at 12 months, with median DFS of 19.3 months (95% CI=7.4 months to [upper bound not reached]). Most treatment-emergent adverse events for patients receiving BCG plus NAI were grade 1 to 2 (86%); three grade 3 immune-related treatment-emergent adverse events occurred. CONCLUSIONS: In patients with BCG-unresponsive bladder carcinoma in situ and papillary NMIBC treated with BCG and the novel agent NAI, CRs were achieved with a persistence of effect, cystectomy avoidance, and 100% bladder cancer­specific survival at 24 months. The study is ongoing, with an estimated target enrollment of 200 participants (Funded by ImmunityBio.)

Heterologous saRNA Prime, DNA Dual-Antigen Boost SARS-CoV-2 Vaccination Elicits Robust Cellular Immunogenicity and Cross-Variant Neutralizing Antibodies.

We assessed if immune responses are enhanced in CD-1 mice by heterologous vaccination with two different nucleic acid-based COVID-19 vaccines: a next-generation human adenovirus serotype 5 (hAd5)-vectored dual-antigen spike (S) and nucleocapsid (N) vaccine (AdS+N) and a self-amplifying and -adjuvanted S RNA vaccine (AAHI-SC2) delivered by a nanostructured lipid carrier. The AdS+N vaccine encodes S modified with a fusion motif to increase cell-surface expression and an N antigen modified with an Enhanced T-cell Stimulation Domain (N-ETSD) to direct N to the endosomal/lysosomal compartment and increase MHC class I and II stimulation potential. The S sequence in the AAHI-SC2 vaccine comprises the D614G mutation, two prolines to stabilize S in the prefusion conformation, and 3 glutamines in the furin cleavage region to confer protease resistance. CD-1 mice received vaccination by homologous and heterologous prime > boost combinations. Humoral responses to S were the highest with any regimen that included the AAHI-SC2 vaccine, and IgG bound to wild type and Delta (B.1.617.2) variant S1 at similar levels. An AAHI-SC2 prime followed by an AdS+N boost particularly enhanced CD4+ and CD8+ T-cell responses to both wild type and Delta S peptides relative to all other vaccine regimens. Sera from mice receiving AAHI-SC2 homologous or heterologous vaccination were found to be highly neutralizing for all pseudovirus strains tested: Wuhan, Beta, Delta, and Omicron strains. The findings here, taken in consideration with the availability of both vaccines in thermostable formulations, support the testing of heterologous vaccination by an AAHI-SC2 > AdS+N regimen in animal models of SARS-CoV-2 infection to assess its potential to provide increased protection against emerging SARS-CoV-2 variants particularly in regions of the world where the need for cold-chain storage has limited the distribution of other vaccines.

Safety, Feasibility, and Merits of Longitudinal Molecular Testing of Multiple Metastatic Sites to Inform mTNBC Patient Treatment in the Intensive Trial of Omics in Cancer.

PURPOSE: Patients with metastatic triple-negative breast cancer (mTNBC) have poor outcomes. The Intensive Trial of Omics in Cancer (ITOMIC) sought to determine the feasibility and potential efficacy of informing treatment decisions through multiple biopsies of mTNBC deposits longitudinally over time, accompanied by analysis using a distributed network of experts. METHODS: Thirty-one subjects were enrolled and 432 postenrollment biopsies performed (clinical and study-directed) of which 332 were study-directed. Molecular profiling included whole-genome sequencing or whole-exome sequencing, cancer-associated gene panel sequencing, RNA-sequencing, and immunohistochemistry. To afford time for analysis, subjects were initially treated with cisplatin (19 subjects), or another treatment they had not received previously. The results were discussed at a multi-institutional ITOMIC Tumor Board, and a report transmitted to the subject's oncologist who arrived at the final treatment decision in conjunction with the subject. Assistance was provided to access treatments that were predicted to be effective. RESULTS: Multiple biopsies in single settings and over time were safe, and comprehensive analysis was feasible. Two subjects were found to have lung cancer, one had carcinoma of unknown primary site, tumor samples from three subjects were estrogen receptor-positive and from two others, human epidermal growth factor receptor 2-positive. Two subjects withdrew. Thirty-four of 112 recommended treatments were accessed using approved drugs, clinical trials, and single-patient investigational new drugs. After excluding the three subjects with nonbreast cancers and the two subjects who withdrew, 22 of 26 subjects (84.6%) received at least one ITOMIC Tumor Board-recommended treatment. CONCLUSION: Further exploration of this approach in patients with mTNBC is merited.

Dual-Antigen COVID-19 Vaccine Subcutaneous Prime Delivery With Oral Boosts Protects NHP Against SARS-CoV-2 Challenge.

We have developed a dual-antigen COVID-19 vaccine incorporating genes for a modified SARS-CoV-2 spike protein (S-Fusion) and the viral nucleocapsid (N) protein with an Enhanced T-cell Stimulation Domain (N-ETSD) to increase the potential for MHC class II responses. The vaccine antigens are delivered by a human adenovirus serotype 5 platform, hAd5 [E1-, E2b-, E3-], previously demonstrated to be effective in the presence of Ad immunity. Vaccination of rhesus macaques with the hAd5 S-Fusion + N-ETSD vaccine by subcutaneous prime injection followed by two oral boosts elicited neutralizing anti-S IgG and T helper cell 1-biased T-cell responses to both S and N that protected the upper and lower respiratory tracts from high titer (1 x 106 TCID50) SARS-CoV-2 challenge. Notably, viral replication was inhibited within 24 hours of challenge in both lung and nasal passages, becoming undetectable within 7 days post-challenge.

Intranasal plus subcutaneous prime vaccination with a dual antigen COVID-19 vaccine elicits T-cell and antibody responses in mice.

We have developed a COVID-19 vaccine, hAd5 S-Fusion + N-ETSD, that expresses SARS-CoV-2 spike (S) and nucleocapsid (N) proteins with modifications to increase immune responses delivered using a human adenovirus serotype 5 (hAd5) platform. Here, we demonstrate subcutaneous (SC) prime and SC boost vaccination of CD-1 mice with this dual-antigen vaccine elicits T-helper cell 1 (Th1) biased T-cell and humoral responses to both S and N that are greater than those seen with hAd5 S wild type delivering only unmodified S. We then compared SC to intranasal (IN) prime vaccination with SC or IN boosts and show that an IN prime with an IN boost is as effective at generating Th1 biased humoral responses as the other combinations tested, but an SC prime with an IN or SC boost elicits greater T cell responses. Finally, we used a combined SC plus IN (SC + IN) prime with or without a boost and found the SC + IN prime alone to be as effective in generating humoral and T-cell responses as the SC + IN prime with a boost. The finding that SC + IN prime-only delivery has the potential to provide broad immunity-including mucosal immunity-against SARS-CoV-2 supports further testing of this vaccine and delivery approach in animal models of viral challenge.

Identification and validation of expressed HLA-binding breast cancer neoepitopes for potential use in individualized cancer therapy.

BACKGROUND: Therapeutic regimens designed to augment the immunological response of a patient with breast cancer (BC) to tumor tissue are critically informed by tumor mutational burden and the antigenicity of expressed neoepitopes. Herein we describe a neoepitope and cognate neoepitope-reactive T-cell identification and validation program that supports the development of next-generation immunotherapies. METHODS: Using GPS Cancer, NantOmics research, and The Cancer Genome Atlas databases, we developed a novel bioinformatic-based approach which assesses mutational load, neoepitope expression, human leukocyte antigen (HLA)-binding prediction, and in vitro confirmation of T-cell recognition to preferentially identify targetable neoepitopes. This program was validated by application to a BC cell line and confirmed using tumor biopsies from two patients with BC enrolled in the Tumor-Infiltrating Lymphocytes and Genomics (TILGen) study. RESULTS: The antigenicity and HLA-A2 restriction of the BC cell line predicted neoepitopes were determined by reactivity of T cells from HLA-A2-expressing healthy donors. For the TILGen subjects, tumor-infiltrating lymphocytes (TILs) recognized the predicted neoepitopes both as peptides and on retroviral expression in HLA-matched Epstein-Barr virus-lymphoblastoid cell line and BC cell line MCF-7 cells; PCR clonotyping revealed the presence of T cells in the periphery with T-cell receptors for the predicted neoepitopes. These high-avidity immune responses were polyclonal, mutation-specific and restricted to either HLA class I or II. Interestingly, we observed the persistence and expansion of polyclonal T-cell responses following neoadjuvant chemotherapy. CONCLUSIONS: We demonstrate our neoepitope prediction program allows for the successful identification of neoepitopes targeted by TILs in patients with BC, providing a means to identify tumor-specific immunogenic targets for individualized treatment, including vaccines or adoptively transferred cellular therapies.

Complete response to avelumab and IL-15 superagonist N-803 with Abraxane in Merkel cell carcinoma: a case study.

Merkel cell carcinoma (MCC) is a rare aggressive form of skin cancer originating in neuroendocrine cells. The antiprogrammed death ligand 1 (PD-L1) monoclonal antibody (mAb) avelumab has been approved for treatment of MCC, but options are limited, should it be ineffective as a monotherapy. Combined therapy with low/moderate dose nab-paclitaxel and an interleukin 15 (IL-15)-based therapeutic such as the IL-15 'superagonist' N-803 may increase response by activation of the immune system. The case of a 71-year-old man diagnosed with MCC who achieved and maintained a complete response (CR) by treatment with the anti-PD-L1 mAb avelumab in combination with IL-15 superagonist N-803 and nab-paclitaxel (Abraxane) is presented. Avelumab treatment alone resulted in a response in a para-aortic lesion, but not the other tumor masses. N-803 was added, followed by nab-paclitaxel; CT showed a decrease in the size of the abdominal mass at 1 month, near resolution at 3 months and CR at 5 months. Abraxane was discontinued after the first CR on CT, and the patient continues on avelumab/N-803 treatment and maintains a CR. Combination of avelumab with low/moderate-dose chemotherapy and an immune enhancer such as N-803 may offer a viable treatment option for MCC patients for whom avelumab therapy alone was not effective.

A small molecule ApoE4-targeted therapeutic candidate that normalizes sirtuin 1 levels and improves cognition in an Alzheimer's disease mouse model.

We describe here the results from the testing of a small molecule first-in-class apolipoprotein E4 (ApoE4)-targeted sirtuin1 (SirT1) enhancer, A03, that increases the levels of the neuroprotective enzyme SirT1 while not affecting levels of neurotoxic sirtuin 2 (SirT2) in vitro in ApoE4-transfected cells. A03 was identified by high-throughput screening (HTS) and found to be orally bioavailable and brain penetrant. In vivo, A03 treatment increased SirT1 levels in the hippocampus of 5XFAD-ApoE4 (E4FAD) Alzheimer's disease (AD) model mice and elicited cognitive improvement while inducing no observed toxicity. We were able to resolve the enantiomers of A03 and show using in vitro models that the L-enantiomer was more potent than the corresponding D-enantiomer in increasing SirT1 levels. ApoE4 expression has been shown to decrease the level of the NAD-dependent deacetylase and major longevity determinant SirT1 in brain tissue and serum of AD patients as compared to normal controls. A deficiency in SirT1 level has been recently implicated in increased tau acetylation, a dominant post-translational modification and key pathological event in AD and tauopathies. Therefore, as a novel approach to therapeutic development for AD, we targeted identification of compounds that enhance and normalize brain SirT1 levels.

Evaluation of an Allosteric BACE Inhibitor Peptide to Identify Mimetics that Can Interact with the Loop F Region of the Enzyme and Prevent APP Cleavage.

The aspartyl protease BACE1 (BACE) has emerged as an appealing target for reduction of amyloid-ß in Alzheimer's disease. The clinical fate of active-site BACE inhibitors may depend on potential side effects related to enzyme and substrate selectivity. One strategy to reduce this risk is through development of allosteric inhibitors that interact with and modulate the Loop F region unique to BACE1. Previously, a BACE-inhibiting antibody (Ab) was shown by co-crystallization to bind and induce conformational changes of Loop F, resulting in backbone perturbations at the distal S6 and S7 subsites, preventing proper binding of a long APP-like substrate to BACE and inhibiting its cleavage. In an effort to discover small Loop F-interacting molecules that mimic the Ab inhibition, we evaluated a peptide series with a YPYF(I/L)P(L/Y) motif that was reported to bind a BACE exosite. Our studies show that the most potent inhibitor from this series, peptide 65007, has a similar substrate cleavage profile to the Ab and reduces sAPPß levels in cell models and primary neurons. As our modeling indicates, it interacts with the Loop F region causing a conformational shift of the BACE protein backbone near the distal subsites. The peptide-bound enzyme adopts a conformation that closely overlays with the crystal structure (PDB: 3R1G) from Ab binding. Importantly, peptide 65007 appears to be BACE substrate and enzyme selective, showing little inhibition of NRG1, PSGL1, CHL1, or Cat D. Thus, peptide 65007 is a promising lead for discovery of Loop F-interacting small-molecule mimetics as allosteric inhibitors of BACE.

Netrin-1 Interrupts Amyloid-ß Amplification, Increases sAßPPα in vitro and in vivo, and Improves Cognition in a Mouse Model of Alzheimer's Disease.

Recent studies have shown that inoculation of susceptible mice with amyloid-ß (Aß) peptides accelerates Aß deposition in the brain, supporting the idea that Aß may be self-amplifying; however, the exact mechanism is not understood. Here we provide evidence that Aß may self-amplify, in part, by inhibiting α-secretase ADAM10 (a disintegrin and metalloprotease) cleavage of full-length Aß precursor protein (FL AßPP) and therefore allow greater ß-secretase processing, and that Aß itself is a substrate for ADAM10. Exposure of primary neuronal cultures from PDAßPP mice to exogenous rat Aß1- 40 resulted in increased de novo human Aß1-42 production and exposure of cells to Aß decreased production of ADAM10 cleavage product soluble AßPPα (sAßPPα). In a cell-free assay, Aß decreased ADAM10 cleavage of the chimeric substrate MBP-AßPPC125 and Aß itself was apparently cleaved by the enzyme. The axonal guidance and trophic factor netrin-1, however, reduced the Aß1- 40-induced Aß1-42 increase, increased sAßPPα, and reversed the Aß-induced sAßPPα decrease in vitro. In vivo, induction of netrin-1 expression in PDAßPPSwe/Ind transgenic mice resulted in reductions in both Aß1-42 and Aß1- 40, and ICV delivery of netrin-1 to PDAßPPSwe/Ind mice increased sAßPPα, decreased Aß, and improved working memory. Finally, to support further study of netrin-1's potential as a therapeutic for Alzheimer's disease, pilot gene therapy studies were performed and a netrin mimetic peptide synthesized and tested that, like netrin, can increase sAßPPα and decrease Aß1-42in vitro. Taken together, these data provide mechanistic insights into Aß self-amplification and the ability of netrin-1 to disrupt it.

Direct Transcriptional Effects of Apolipoprotein E.

A major unanswered question in biology and medicine is the mechanism by which the product of the apolipoprotein E ε4 allele, the lipid-binding protein apolipoprotein E4 (ApoE4), plays a pivotal role in processes as disparate as Alzheimer's disease (AD; in which it is the single most important genetic risk factor), atherosclerotic cardiovascular disease, Lewy body dementia, hominid evolution, and inflammation. Using a combination of neural cell lines, skin fibroblasts from AD patients, and ApoE targeted replacement mouse brains, we show in the present report that ApoE4 undergoes nuclear translocation, binds double-stranded DNA with high affinity (low nanomolar), and functions as a transcription factor. Using chromatin immunoprecipitation and high-throughput DNA sequencing, our results indicate that the ApoE4 DNA binding sites include ∼1700 gene promoter regions. The genes associated with these promoters provide new insight into the mechanism by which AD risk is conferred by ApoE4, because they include genes associated with trophic support, programmed cell death, microtubule disassembly, synaptic function, aging, and insulin resistance, all processes that have been implicated in AD pathogenesis. Significance statement: This study shows for the first time that apolipoprotein E4 binds DNA with high affinity and that its binding sites include 1700 promoter regions that include genes associated with neurotrophins, programmed cell death, synaptic function, sirtuins and aging, and insulin resistance, all processes that have been implicated in Alzheimer's disease pathogenesis.

Paradoxical effect of TrkA inhibition in Alzheimer's disease models.

An unbiased screen for compounds that block amyloid-ß protein precursor (AßPP) caspase cleavage identified ADDN-1351, which reduced AßPP-C31 by 90%. Target identification studies showed that ADDN-1351 is a TrkA inhibitor, and, in complementary studies, TrkA overexpression increased AßPP-C31 and cell death. TrkA was shown to interact with AßPP and suppress AßPP-mediated transcriptional activation. Moreover, treatment of PDAPP transgenic mice with the known TrkA inhibitor GW441756 increased sAßPPα and the sAßPPα to Aß ratio. These results suggest TrkA inhibition-rather than NGF activation-as a novel therapeutic approach, and raise the possibility that such an approach may counteract the hyperactive signaling resulting from the accumulation of active NGF-TrkA complexes due to reduced retrograde transport. The results also suggest that one component of an optimal therapy for Alzheimer's disease may be a TrkA inhibitor.

Endogenously EGFP-Labeled Mouse Embryonic Stem Cells.

Transplantation of embryonic stem cell (ESC)-derived precursors holds great promise for treating various disease conditions. Tracing of precursors derived from ESC after transplantation is important to determine their migration and fate. Chemical labeling, as well as transfection or viral-mediated transduction of tracer genes in ESC or in ESC-derived precursors, which are the methods that have been used in the generation of the vast majority of labeled ESCs, have serious drawbacks such as varying efficacy. To circumvent this problem we generated endogenously traceable mouse (m)ESC clones by direct derivation from blastocysts of transgenic mice expressing enhanced green fluorescent protein (EGFP) under control of the housekeeping ß-actin promoter The only previous report of endogenously EGFP-labeled mESC derived directly from transgenic EGFP embryos is that of Ahn and colleagues (Ahn et al, 2008. Cytotherapy 10:759-769), who used embryos from a different transgenic line and used a significantly different protocol for derivation. Cells from a high-expressing EGFP-mESC clone, G11, retain high levels of EGFP expression after differentiation into derivatives of all three primary germ layers both in vitro and in vivo, and contribution to all tissues in chimeric progeny. To determine whether progenitor cells derived from G11 could be used in transplantation experiments, we differentiated them to early neuronal precursors and injected them into syngeneic mouse brains. Transplanted EGFP-expressing cells at different stages of differentiation along the neuronal lineage could be identified in brains by expression of EGFP twelve weeks after transplantation. Our results suggest that the EGFP-mESC(G11) line may constitute a useful tool in ESC-based cell and tissue replacement studies.