Development of new radiopharmaceutical for molecular imaging in oncology

De afgelopen jaren zijn diverse nieuwe geneesmiddelen tegen kanker ontwikkeld. Er kan echter nog niet goed vooraf voorspeld worden bij welke patiënt deze nieuwe geneesmiddelen zullen werken. Niet-invasieve nucleair afbeeldende technieken zoals ‘Single Photon Emission Computed Tomography’ (SPECT) en ‘Positron Emission Tomography’ (PET) zouden kunnen bijdragen aan het selecteren van de juiste patiënt voor een bepaald geneesmiddel en het beoordelen van het resultaat van de behandeling met dat geneesmiddel. In dit proefschrift worden twee belangrijke aangrijpingspunten van huidige en toekomstige anti-kankergeneesmiddelen verkend: de ‘human epidermal growth factor receptor 2’ (HER2) en de extrinsieke apoptotische route. Allereerst liet de nieuw ontwikkelde PET tracer 89Zr-trastuzumab voor HER2 beeldvorming in preklinisch onderzoek een hoge en HER2 specifiek tumoropname zien met een goede resolutie. De eerste klinische toepassing van 89Zr-trastuzumab maakte duidelijk dat deze PET tracer bruikbaar is voor visualisering en kwantificering van HER2 positieve tumorlaesies in patiënten met uitgezaaide borstkanker, mits de juiste trastuzumab eiwitdosis wordt gegeven. Dit is onder andere afhankelijk van het feit of de patiënt al behandeld wordt met trastuzumab of niet. Daarnaast werden de pro-apoptotische eiwitten rhTRAIL en mapatumumab radioactief gelabeld en de biodistributie en tumoraccumulatie bestudeerd in preklinische modellen met een humaan tumortransplantaat met hoge of lage TRAIL-R1 en TRAIL-R2 death receptor expressie op de tumorcellen. Het rhTRAIL en mapatumumab konden efficiënt worden gelabeld en worden toegepast om farmacokinetiek te bestuderen. In patiënten met uitgezaaide kanker bleek radioactief mapatumumab potentieel te kunnen bijdragen aan het op voorhand selecteren van patiënten voor antitumor therapie met mapatumumab. Tenslotte werd gedemonstreerd dat grote hoeveelheden eiwit (zoals scFv425:TRAIL) geproduceerd kunnen worden door gebruik te maken van een ‘solid-support cell growth matrix system’

Postulated Adjuvant Therapeutic Strategies for COVID-19

The number of COVID-19 patients is still growing exponentially worldwide due to the high transmissibility of the SARS-CoV-2 virus. Therapeutic agents currently under investigation are antiviral drugs, vaccines, and other adjuvants that could relieve symptoms or improve the healing process. In this review, twelve therapeutic agents that could play a role in prophylaxis or improvement of the COVID-19-associated symptoms (as add-on substances) are discussed. Agents were identified based on their known pharmacologic mechanism of action in viral and/or nonviral fields and are postulated to interact with one or more of the seven known mechanisms associated with the SARS-CoV-2 virus: (i) regulation of the immune system; (ii) virus entrance in the cell; (iii) virus replication; (iv) hyperinflammation; (v) oxidative stress; (vi) thrombosis; and (vii) endotheliitis. Selected agents were immune transfer factor (oligo- and polypeptides from porcine spleen, ultrafiltered at <10 kDa; Imuno TF®), anti-inflammatory natural blend (Uncaria tomentosa, Endopleura uchi and Haematoccocus pluvialis; Miodesin®), zinc, selenium, ascorbic acid, cholecalciferol, ferulic acid, spirulina, N-acetylcysteine, glucosamine sulfate potassium hydrochloride, trans-resveratrol, and maltodextrin-stabilized orthosilicic acid (SiliciuMax®). This review gives the scientific background on the hypothesis that these therapeutic agents can act in synergy in the prevention and improvement of COVID-19-associated symptoms

Robust, high-throughput LC-MS/MS method for therapeutic drug monitoring of cyclosporine, tacrolimus, everolimus, and sirolimus in whole blood

The authors describe a fast, robust, and straightforward liquid chromatography and tandem mass spectrometry (LC-MS/MS) method with the use of a single LC-MS/MS system for cyclosporine A, tacrolimus, sirolimus, and everolimus in whole blood. The purpose of this method was to replace the immunoassay (IA) methods used in the laboratory of a hospital performing most organ transplantations (including heart, lung, liver, kidneys, bone marrow, and intestinal tract). Several LC-MS/MS methods have been described so far; however, most of them require complicated online extraction procedures. The described LC-MS/MS method uses a chromatographic gradient in combination with protein precipitation as sample preparation. The chromatographic method is capable of separating otherwise interfering peaks, with an analysis time of 2.6 minutes. Analyses were performed on a triple quadrupole LCMS/MS system, with a C 18 column held at 60 degrees C. Sample preparation required only 1 precipitation/dilution step. Sirolimus and everolimus are prepared and measured separately from tacrolimus and cyclosporine. During method development, it was found that the use of zinc sulfate provides process efficiency results of about 100% for tacrolimus and cyclosporine A, but only 81% and 87% for sirolimus and everolimus, respectively. With the developed sample preparation without zinc sulfate for sirolimus and everolimus, process efficiencies were 99% and 108%, respectively. The methods have been fully validated, and in a comparative study, patient samples were analyzed with IA and Our developed LC-MS/MS methods. In the comparative studies, correlations (R 2 values) of more than 0.85 were found between the IA and the new LC-MS/MS patient blood levels. There was a systematic deviation in blood levels measured by LCM-SiMS compared with lAs for cyclosporine A (17% lower than with immunoassay) and everolimus (30% lower than with IA). There seemed to be little or no systematic deviation for sirolimus and tacrolimus. The controls determined by the LC-MS/MS method over the past 10 months showed coefficient of variations of no more than 8.0% for each of the 4 immunosuppressants. In conclusion, the authors found the developed methods to be cost saving, more flexible, and more sensitive and that these methods have larger linear ranges than the previously used IA methods. The methods are already used for more than 20,000 patient samples in the daily routine, analyzing approximately 70 patient samples per day

Characterization and Safety Profile of Transfer Factors Peptides, a Nutritional Supplement for Immune System Regulation

Imuno TF® is a nutritional supplement composed of isolated transfer factors (TF) from porcine spleen. It is composed of a specific mixture of molecules that impact functions of the biological systems and historically is linked to the immune system regulation. In this study, we demonstrate for the first time its proteomic analysis, nutritional composition, and safety profile in terms of mutagenic potential and acute oral dose (LD50). The obtained analysis indicated the product is a complex set of oligo- and polypeptides constituted of 163 different peptides which can potentially act on multiple mechanisms on the immune system pathways. The chemical composition showed low fat and low sugar content, saturated fatty acids-free, and the presence of 10 vitamins and 11 minerals. No mutagenic effect was observed, and the LD50 was 5000 mg kg−1 body weight. This accounts for a safe product to be used by the oral route, with potential benefits for the immune system

Evaluation of RGD-targeted albumin carriers for specific delivery of auristatin E to tumor blood vessels

Induction of apoptosis in endothelial cells is considered an attractive strategy to therapeutically interfere with a solid tumor's blood supply. In the present paper, we constructed cytotoxic conjugates that specifically target angiogenic endothelial cells, thus preventing typical side effects of apoptosis-inducing drugs. For this purpose, we conjugated the potent antimitotic agent monomethyl-auristatin-E ( MMAE) via a lysosomal cleavable linker to human serum albumin ( HSA) and further equipped this drug-albumin conjugate with cyclic c( RGDfK) peptides for multivalent interaction with alpha(v)beta(3)-integrin. The RGD-peptides were conjugated via either an extended poly( ethylene glycol) linker or a short alkyl linker. The resulting drug-targeting conjugates RGDPEG-MMAE-HSA and RGD-MMAE-HSA demonstrated high binding affinity and specificity for alpha(v)beta(3)-integrin expressing human umbilical vein endothelial cells ( HUVEC). Both types of conjugates were internalized by endothelial cells and killed the target cells at low nM concentrations. Furthermore, we observed RGD-dependent binding of the conjugates to C26 carcinoma. Upon i.v. administration to C26-tumor bearing mice, both drug-targeting conjugates displayed excellent tumor homing properties. Our results demonstrate that RGD-modified albumins are suitable carriers for cell selective intracellular delivery of cytotoxic compounds, and further studies will be conducted to assess the antivascular and tumor inhibitory potential of RGDPEG-MMAE-HSA and RGD-MMAE-HSA

Immunoscintigraphy as Potential Tool in the Clinical Evaluation of HER2/neu Targeted Therapy

Many new targeted anticancer drugs have been developed. In order for these drugs to be effective, the tumor target has to be present during treatment. Currently there are only a few biomarkers available to help the physician select the appropriate targeted drug for the patient and often tumor tissue is required for biomarker assays. Immunoscintigraphy might be able to improve diagnostic imaging, to guide antibody based therapy and to support early antibody development. Many different radiopharmaceuticals have been developed and used to visualize all kind of different targets especially in oncology. Intact radiolabeled antibodies generally show high tumor uptake but low tumor-to-blood ratios, particularly at early time points. Radiolabeled antibody fragments and proteins show widely differing values for tumor uptake and tumor-to-blood contrast. One of the promising targets for visualization might be HER2/neu. HER2/neu scans may prove useful for tumor staging, guiding of targeted therapy and measuring target occupancy in early drug development. Immunoscintigraphic clinical studies performed with intact antibodies indicate that HER2/neu imaging is feasible. Additional research will be performed to prove its value and make this technique applicable on a larger scale. The aim of this review is to describe the types of radiopharmaceuticals that are available, and the potential role of immunoscintigraphy in improving diagnostic imaging, guiding monoclonal antibody (mAb)-based therapy and supporting the development of mAb-based drugs using the HER2/neu target as an example

Multidrug resistance in oncology and beyond:from imaging of drug efflux pumps to cellular drug targets

Resistance of tumor cells to several structurally unrelated classes of natural products, including anthracyclines, taxanes, and epipodophyllotoxines, is often referred as multidrug resistance (MDR). This is associated with ATP-binding cassette transporters, which function as drug efflux pumps such as P-glycoprotein (Pgp) and multidrug resistance-associated protein 1 (MRP1). Because of the hypothesis in the early eighties that blockade of these efflux pumps by modulators would improve the effect of chemotherapy, extensive effort has been put to visualize these pumps using nuclear imaging with several specific tracers, using both SPECT and PET techniques. The methods and possibilities to visualize these pumps in both the tumor and the blood-brain barrier will be discussed. Because of the fact that the addition of Pgp or MRP modulators has not shown any clinical benefit in patient outcome, these specific MDR tracers are not routinely used in clinical practice. Evidence emerges that combination of chemotherapeutic drugs involved in MDR with the so-called targeted agents can improve patient outcome. The concept of molecular imaging can also be used to visualize the targets for these agents, such as HER2/neu and angiogenic factors such as vascular endothelial growth factor (VEGF). Potentially visualizing molecular drug targets in the tumor can function as biomarkers to support treatment decision for the individual patient