Convective forces increase rostral delivery of intrathecal radiotracers and antisense oligonucleotides in the cynomolgus monkey nervous system.

BACKGROUND: The intrathecal (IT) dosing route introduces drugs directly into the CSF to bypass the blood-brain barrier and gain direct access to the CNS. We evaluated the use of convective forces acting on the cerebrospinal fluid as a means for increasing rostral delivery of IT dosed radioactive tracer molecules and antisense oligonucleotides (ASO) in the monkey CNS. We also measured the cerebral spinal fluid (CSF) volume in a group of cynomolgus monkeys. METHODS: There are three studies presented, in each of which cynomolgus monkeys were injected into the IT space with radioactive tracer molecules and/or ASO by lumbar puncture in either a low or high volume. The first study used the radioactive tracer 64Cu-DOTA and PET imaging to evaluate the effect of the convective forces. The second study combined the injection of the radioactive tracer 99mTc-DTPA and ASO, then used SPECT imaging and ex vivo tissue analysis of the effects of convective forces to bridge between the tracer and the ASO distributions. The third experiment evaluated the effects of different injection volumes on the distribution of an ASO. In the course of performing these studies we also measured the CSF volume in the subject monkeys by Magnetic Resonance Imaging. RESULTS: It was consistently found that larger bolus dose volumes produced greater rostral distribution along the neuraxis. Thoracic percussive treatment also increased rostral distribution of low volume injections. There was little added benefit on distribution by combining the thoracic percussive treatment with the high-volume injection. The CSF volume of the monkeys was found to be 11.9 ± 1.6 cm3. CONCLUSIONS: These results indicate that increasing convective forces after IT injection increases distribution of molecules up the neuraxis. In particular, the use of high IT injection volumes will be useful to increase rostral CNS distribution of therapeutic ASOs for CNS diseases in the clinic.

Cystine-knot peptides: emerging tools for cancer imaging and therapy.

Cystine-knot miniproteins, also known as knottins, constitute a large family of structurally related peptides with diverse amino acid sequences and biological functions. Knottins have emerged as attractive candidates for drug development as they potentially fill a niche between small molecules and protein biologics, offering drug-like properties and the ability to bind to clinical targets with high affinity and selectivity. Due to their extremely high stability and unique structural features, knottins also demonstrate promise in addressing challenging drug development goals, including the potential for oral delivery and the ability to access intracellular drug targets. Several naturally-occurring knottins have recently received approval for treating chronic pain and irritable bowel syndrome, while others are under development for tumor imaging applications. To expand beyond nature's repertoire, rational and combinatorial protein engineering methods are generating tumor-targeting knottins for use as cancer diagnostics and therapeutics.

Increased Risk of Venous Thromboembolism in Patients With Amyotrophic Lateral Sclerosis: Results From a US Insurance Claims Database Study.

Background and Objectives: Reduced mobility in patients with amyotrophic lateral sclerosis (ALS) is hypothesized to increase the risk of venous thromboembolism (VTE). A few small, single-center studies have investigated the risk of VTE in patients with ALS. Given the high morbidity and mortality associated with VTE, further understanding of the risk in patients with ALS may inform clinical care. The objective of this study was to investigate the incidence of VTE in patients with ALS compared with controls without ALS. Methods: Patients were identified from a US health insurance claims database, Optum's deidentified Clinformatics Data Mart Database, between 2004 and 2019. ALS cases were defined as patients aged 18 years or older with (1) 2 or more ALS claims at least 27 days apart including at least 1 claim from a neurologist visit or (2) 1 or more ALS claims and a prescription for riluzole or edaravone. Each ALS case was matched on age and sex to 5 controls without ALS. VTE was defined as at least 1 claim for VTE and at least 1 anticoagulant prescription or VTE-related procedure within 7 days before and 30 days after a VTE claim date. Incidence rates were reported per 1,000 person-years. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using the Cox proportional hazards model. Results: Among 4,205 ALS cases and 21,025 controls, incident VTE occurred in 132 ALS cases (3.1%) and 244 controls (1.2%). Incidence rates of VTE were 19.9 per 1,000 person-years (95% CI 16.7-23.6) in ALS cases compared with 6.0 per 1,000 person-years (95% CI 5.0-7.1) in controls. ALS cases were about 3 times more likely to develop VTE (HR 3.3, 95% CI 2.6-4.0), with similar results among men and women. The median time to first VTE was 10 months from the initial ALS claim in ALS cases. Discussion: Consistent with previous smaller studies, a higher incidence rate of VTE was observed in a large sample of patients with ALS from across the United States, as compared to matched controls. The markedly increased risk underscores the importance of preventive efforts and careful monitoring for VTE in patients with ALS and may have implications for the management of ALS.

Dynamic expression of a LEF-EGFP Wnt reporter in mouse development and cancer.

We have characterized a transgenic mouse line in which enhanced green fluorescent protein (EGFP) is expressed under the control of multimerized LEF-1 responsive elements. In embryos, EGFP was detected in known sites of Wnt activation, including the primitive streak, mesoderm, neural tube, somites, heart, limb buds, mammary placodes, and whisker follicles. In vitro cultured transgenic embryonic fibroblasts upregulated EGFP expression in response to activation of Wnt signaling by GSK3beta inhibition. Mammary tumor cell lines derived from female LEF-EGFP transgenic mice treated with the carcinogen 7, 12-dimethylbenz[a]anthracene (DMBA) also express EGFP. Thus, this transgenic line is useful for ex vivo and in vitro studies of Wnt signaling in development and cancer.

Discovery and pharmacologic characterization of CP-724,714, a selective ErbB2 tyrosine kinase inhibitor.

Amplification and overexpression of erbB2 (Her-2/neu) proto-oncogene has been linked to human malignancies including tumors of the breast, ovary, and stomach. It has been implicated in tumor growth, sensitivity to standard chemotherapy, prognosis of patients, and disease-free survival. Although the clinical use of trastuzumab (Herceptin) has prolonged the survival of breast cancer patients with erbB2-overexpressing tumors, there is an urgent need for more potent and orally bioavailable small-molecule inhibitors. CP-724,714 is a potent inhibitor of erbB2 receptor autophosphorylation in intact cells and is currently undergoing phase I clinical trials. Here, we describe the effects of CP-724,714 in vitro and in vivo in human breast cancer models. CP-724,714 is selective for inhibiting growth of HER2-driven cell lines. In addition, we show that it induces G1 cell cycle block in erbB2-overexpressing BT-474 human breast carcinoma cells and inhibits erbB2 autophosphorylation in xenografts when administered p.o. to athymic mice. It induces a marked reduction of extracellular signal-regulated kinase and Akt phosphorylation, tumor cell apoptosis, and release of caspase-3. P.o. administration (q.d. or b.i.d.) of CP-724,714 inhibits the growth of erbB2-overexpressing tumors in athymic mice without overt adverse effects.

Targeted Drug Delivery with an Integrin-Binding Knottin-Fc-MMAF Conjugate Produced by Cell-Free Protein Synthesis.

Antibody-drug conjugates (ADC) have generated significant interest as targeted therapeutics for cancer treatment, demonstrating improved clinical efficacy and safety compared with systemic chemotherapy. To extend this concept to other tumor-targeting proteins, we conjugated the tubulin inhibitor monomethyl-auristatin-F (MMAF) to 2.5F-Fc, a fusion protein composed of a human Fc domain and a cystine knot (knottin) miniprotein engineered to bind with high affinity to tumor-associated integrin receptors. The broad expression of integrins (including αvß3, αvß5, and α5ß1) on tumor cells and their vasculature makes 2.5F-Fc an attractive tumor-targeting protein for drug delivery. We show that 2.5F-Fc can be expressed by cell-free protein synthesis, during which a non-natural amino acid was introduced into the Fc domain and subsequently used for site-specific conjugation of MMAF through a noncleavable linker. The resulting knottin-Fc-drug conjugate (KFDC), termed 2.5F-Fc-MMAF, had approximately 2 drugs attached per KFDC. 2.5F-Fc-MMAF inhibited proliferation in human glioblastoma (U87MG), ovarian (A2780), and breast (MB-468) cancer cells to a greater extent than 2.5F-Fc or MMAF alone or added in combination. As a single agent, 2.5F-Fc-MMAF was effective at inducing regression and prolonged survival in U87MG tumor xenograft models when administered at 10 mg/kg two times per week. In comparison, tumors treated with 2.5F-Fc or MMAF were nonresponsive, and treatment with a nontargeted control, CTRL-Fc-MMAF, showed a modest but not significant therapeutic effect. These studies provide proof-of-concept for further development of KFDCs as alternatives to ADCs for tumor targeting and drug delivery applications. Mol Cancer Ther; 15(6); 1291-300. ©2016 AACR.

The Eye As a Biomarker for Alzheimer's Disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder resulting in dementia and eventual death. It is the leading cause of dementia and the number of cases are projected to rise in the next few decades. Pathological hallmarks of AD include the presence of hyperphosphorylated tau and amyloid protein deposition. Currently, these pathological biomarkers are detected either through cerebrospinal fluid analysis, brain imaging or post-mortem. Though effective, these methods are not widely available due to issues such as the difficulty in acquiring samples, lack of infrastructure or high cost. Given that the eye possesses clear optics and shares many neural and vascular similarities to the brain, it offers a direct window to cerebral pathology. These unique characteristics lend itself to being a relatively inexpensive biomarker for AD which carries the potential for wide implementation. The development of ocular biomarkers can have far implications in the discovery of treatments which can improve the quality of lives of patients. In this review, we consider the current evidence for ocular biomarkers in AD and explore potential future avenues of research in this area.

CK2 as a positive regulator of Wnt signalling and tumourigenesis.

CK2 is upregulated in rapidly dividing cells including most human tumours. Transgenic overexpression of CK2 in lymphoid or mammary lineages predisposes to transformation. Multiple signalling and oncogene pathways could be regulated by CK2 in this process. Our studies suggest that phosphorylation of critical oncogenes by CK2, as well as by other serine-threonine kinases, regulates their stability via susceptibility to the proteasomal degradation system. Beta-catenin is a transcriptional co-factor in the Wnt signalling pathway that is regulated in this fashion. Inactivating mutations in the adenomatosis polyposis coli (APC) gene, which encodes a carrier protein for beta-catenin, or stabilizing mutations in beta-catenin itself, frequently occur in human tumours. CK2 and the monomeric serine-threonine kinase GSK3 have opposing actions on beta-catenin: GSK-3 phosphorylation of the N-terminus of beta-catenin promotes degradation; while phosphorylation by CK2 in the armadillo repeat protein interaction domain protects it. Beta-catenin is overexpressed in mammary tumours occurring in mice transgenic for CK2 or a dominant negative form of GSK3, and also in mammary tumours arising following treatment with the environmental carcinogen DMBA. Experiments are underway to determine whether expression of both CK2 and kinase inactive GSK3 further accelerates tumorigenesis. Inhibitors of GSK3 under development for treatment of diabetes could promote tumours, while CK2 inhibitors should be useful agents for treatment of cancer.

Oncogenic signaling pathways activated in DMBA-induced mouse mammary tumors.

Only about 5% of human breast cancers can be attributed to inheritance of breast cancer susceptibility genes, while the balance are considered to be sporadic in origin. Breast cancer incidence varies with diet and other environmental influences, including carcinogen exposure. However, the effects of environmental carcinogens on cell growth control pathways are poorly understood. Here we have examined oncogenic signaling pathways that are activated in mammary tumors in mice treated with the prototypical polycyclic aromatic hydrocarbon (PAH) 7,12-dimethylbenz[a]anthracene (DMBA). In female FVB mice given 6 doses of 1 mg of DMBA by weekly gavage beginning at 5 weeks of age, all of the mice developed tumors by 34 weeks of age (median 20 weeks after beginning DMBA); 75% of the mice had mammary tumors. DMBA-induced mammary tumors exhibited elevated expression of the aryl hydrocarbon receptor (AhR), c-myc, cyclin D1, and hyperphosphorylated retinoblastoma (Rb) protein. Because of this, the activation of upstream regulatory pathways was assessed, and elements of the Wnt signaling pathway, the NF-kappa B pathway, and the prolyl isomerase Pin-1 were found to be frequently up-regulated in the tumors when compared to normal mammary gland controls. These data suggest that environmental carcinogens can produce long-lasting alterations in growth and anti-apoptotic pathways, leading to mammary tumorigenesis.

E mu-BRD2 transgenic mice develop B-cell lymphoma and leukemia.

Transgenic mice with lymphoid-restricted overexpression of the double bromodomain protein bromodomain-containing 2 (Brd2) develop splenic B-cell lymphoma and, upon transplantation, B-cell leukemia with leukemic infiltrates in liver and lung. Brd2 is a nuclear-localized transcription factor kinase that is most closely related to TATA box binding protein-associated factor, 250 kDa (TAF(II)250) and the Drosophila developmental protein female sterile homeotic. Constitutive expression of BRD2 in the lymphoid compartment increases cyclin A transcription, "priming" transgenic B cells for proliferation. Mice stochastically develop an aggressive B-cell lymphoma with the features of B-1 cells, including CD5 and surface IgM expression. The B-cell lymphoma is monoclonal for immunoglobulin gene rearrangement and is phenotypically stable. The lymphoblasts are very large and express a transcriptome that is similar to human non-Hodgkin lymphomas. Both a wild-type BRD2 transgene and a kinase-null point mutant drive lymphomagenesis; therefore we propose that, rather than kinase activity, Brd2-mediated recruitment of E2 promoter binding factors (E2Fs) and a specific histone acetyltransferase to the cyclin A promoter by both types of transgene is a mechanistic basis for neoplasia. This report is the first to describe a transgenic mouse model for constitutive expression of a protein with more than one bromodomain.