Circulating Antinuclear Antibodies in Patients with Pelvic Masses Are Associated with Malignancy and Decreased Survival

BACKGROUND: Circulating autoantibodies occur more frequently in cancer patients than in patients without cancer. METHODS AND FINDINGS: We examined sera from patients referred for pelvic mass symptoms to a tertiary university clinic. A total of 127 were diagnosed with epithelial ovarian cancer while 386 had a benign condition. A screen for IgG anti-nuclear antibodies (ANA) by indirect immunofluorescence on HEp-2 cells confirmed a highly significant overrepresentation of ANA in the cancer group where 40% had detectable (i.e., a titer ≥160) ANA compared with less than 12% in the benign group. The overrepresentation of ANA in the cancer group persisted (p<0.0001) after matching the age-profile of the benign group with the ovarian cancer group. Only 19 out of 127 patients in the age-matched benign subgroup were positive for ANA corresponding to an 85% specificity at 40% sensitivity of ANA as the only marker for malignancy. No correlation of ANA positivity in either group with specific bands in immunoblots could be demonstrated even though immunoblot positivity was clearly increased in the malignant group (41% vs. 3%). The presence, strength, and type of ANA did not correlate with serum CA-125 values or with staging, and ANA outcome did not contribute with independent diagnostic information. However, survival was significantly shorter in ANA-positive compared with ANA-negative cancer patients and patients with CA-125 below the median CA-125 value in the cancer group had a significantly decreased survival when positive for ANA. ANA status made no difference in the group with CA-125 values above the median. Also, there was a significant correlation between speckled ANA-strength and histological tumor grade. CONCLUSIONS: Circulating antibodies are a promising source for new biomarkers in cancer. Characterization of epitope specificities and measurements of consecutive samples will be important for further elucidating the role of ANA in evaluating ovarian cancer patients

Data Sheet 1_The Alzheimer's disease 5xFAD mouse model is best suited to investigate pretargeted imaging approaches beyond the blood-brain barrier.docx

Alzheimer's disease (AD) is the most common neurodegenerative disease, with an increasing prevalence. Currently, there is no ideal diagnostic molecular imaging agent for diagnosing AD. Antibodies (Abs) have been proposed to close this gap as they can bind selectively and with high affinity to amyloid β (Aβ)—one of the molecular hallmarks of AD. Abs can even be designed to selectively bind Aβ oligomers or isoforms, which are difficult to target with small imaging agents. Conventionally, Abs must be labeled with long-lived radionuclides which typically results in in high radiation burden to healthy tissue. Pretargeted imaging could solve this challenge as it allows for the use of short-lived radionuclides. To develop pretargeted imaging tools that can enter the brain, AD mouse models are useful as they allow testing of the imaging approach in a relevant animal model that could predict its clinical applicability. Several mouse models for AD have been developed with different characteristics. Commonly used models are: 5xFAD, APP/PS1 and tg-ArcSwe transgenic mice. In this study, we aimed to identify which of these models were best suited to investigate pretargeted imaging approaches beyond the blood brain barrier. We evaluated this by pretargeted autoradiography using the Aβ-targeting antibody 3D6 and an 111In-labeled Tz. Evaluation criteria were target-to-background ratios and accessibility. APP/PS1 mice showed Aβ accumulation in high and low binding brain regions and is as such less suitable for pretargeted purposes. 5xFAD and tg-ArcSwe mice showed similar uptake in high binding regions whereas low uptake in low binding regions and are better suited to evaluate pretargeted imaging approaches. 5xFAD mice are advantaged over tg-ArcSwe mice as pathology can be traced early (6 months compared to 18 months of age) and as 5xFAD mice are commercially available.</p

Pretargeted imaging beyond the blood-brain barrier

Pretargeting is a powerful nuclear imaging strategy to achieve enhanced imaging contrast for nanomedicines and reduce the radiation burden to healthy tissue. Pretargeting is based on bioorthogonal chemistry. The most attractive reaction for this purpose is currently the tetrazine ligation, which occurs between trans-cyclooctene (TCO) tags and tetrazines (Tzs). Pretargeted imaging beyond the blood-brain barrier (BBB) is challenging and has not been reported thus far. In this study, we developed Tz imaging agents that are capable of ligating in vivo to targets beyond the BBB. We chose to develop 18F-labeled Tzs as they can be applied to positron emission tomography (PET) - the most powerful molecular imaging technology. Fluorine-18 is an ideal radionuclide for PET due to its almost ideal decay properties. As a non-metal radionuclide, fluorine-18 also allows for development of Tzs with physicochemical properties enabling passive brain diffusion. To develop these imaging agents, we applied a rational drug design approach. This approach was based on estimated and experimentally determined parameters such as the BBB score, pretargeted autoradiography contrast, in vivo brain influx and washout as well as on peripheral metabolism profiles. From 18 initially developed structures, five Tzs were selected to be tested for their in vivo click performance. Whereas all selected structures clicked in vivo to TCO-polymer deposited into the brain, [18F]18 displayed the most favorable characteristics with respect to brain pretargeting. [18F]18 is our lead compound for future pretargeted neuroimaging studies based on BBB-penetrant monoclonal antibodies. Pretargeting beyond the BBB will allow us to image targets in the brain that are currently not imageable, such as soluble oligomers of neurodegeneration biomarker proteins. Imaging of such currently non-imageable targets will allow early diagnosis and personalized treatment monitoring. This in turn will accelerate drug development and greatly benefit patient care

Astrocytic chloride is brain state dependent and modulates inhibitory neurotransmission in mice

Astrocytes act as a dynamic Cl− reservoir regulating Cl− homeostasis in the CNS. Astrocytic Cl− is high and stable during sleep, it is lower during wakefulness and fluctuates in response to sensory input and motor activity. Efflux of Cl− from astrocytes supports inhibitory transmission in the CNS