Search

Additional file 1: Figure S1. Characterisation of ZEGFR:03115-IR700 binding capacity on EGFR-positive GBM cells. Figure S2. Post-PIT DAMPs release. Figure S3. Ability of 18F-AlF-NOTA-ZEGFR:03115 to accumulate in orthotopic U87-MGvIII tumours. Figure S4. In vivo EGFR-targeted PIT in U87-MGvIII subcutaneous tumours. Figure S5. Immune response to PIT.

Automated 18F-trifluoromethylation provided the first radiosynthesis of [18F]Trifluridine, which shows potential as a PET probe of drug mechanism of action., Trifluoromethyl groups are widespread in medicinal chemistry, yet there are limited 18F-radiochemistry techniques available for the production of the complementary PET agents. Herein, we report the first radiosynthesis of the anticancer nucleoside analogue trifluridine, using a fully automated, clinically-applicable 18F-trifluoromethylation procedure. [18F]Trifluridine was obtained after two synthetic steps in 99%, and a molar activity of 0.4 GBq μmol–1 ± 0.05. Biodistribution and PET-imaging data using HCT116 tumour-bearing mice showed a 2.5 %ID g–1 tumour uptake of [18F]trifluridine at 60 minutes post-injection, with bone uptake becoming a prominent feature thereafter. In vivo metabolite analysis of selected tissues revealed the presence of the original radiolabelled nucleoside analogue, together with deglycosylated and phosphorylated [18F]trifluridine as the main metabolites. Our findings suggest a potential role for [18F]trifluridine as a PET radiotracer for elucidation of drug mechanism of action.

Glioblastomas (GBMs) are high‐grade brain tumors, differentially driven by alterations (amplification, deletion or missense mutations) in the epidermal growth factor receptor (EGFR), that carry a poor prognosis of just 12–15 months following standard therapy. A combination of interventions targeting tumor‐specific cell surface regulators along with convergent downstream signaling pathways may enhance treatment efficacy. Against this background, we investigated a novel photoimmunotherapy approach combining the cytotoxicity of photodynamic therapy with the specificity of immunotherapy. An EGFR‐specific affibody (ZEGFR:03115) was conjugated to the phthalocyanine dye, IR700DX, which when excited with near‐infrared light produces a cytotoxic response. ZEGFR:03115–IR700DX EGFR‐specific binding was confirmed by flow cytometry and confocal microscopy. The conjugate showed effective targeting of EGFR positive GBM cells in the brain. The therapeutic potential of the conjugate was assessed both in vitro, in GBM cell lines and spheroids by the CellTiter‐Glo® assay, and in vivo using subcutaneous U87‐MGvIII xenografts. In addition, mice were imaged pre‐ and post‐PIT using the IVIS/Spectrum/CT to monitor treatment response. Binding of the conjugate correlated to the level of EGFR expression in GBM cell lines. The cell proliferation assay revealed a receptor‐dependent response between the tested cell lines. Inhibition of EGFRvIII+ve tumor growth was observed following administration of the immunoconjugate and irradiation. Importantly, this response was not seen in control tumors. In conclusion, the ZEGFR:03115–IR700DX showed specific uptake in vitro and enabled imaging of EGFR expression in the orthotopic brain tumor model. Moreover, the proof‐of‐concept in vivo PIT study demonstrated therapeutic efficacy of the conjugate in subcutaneous glioma xenografts., What's new? Photoimmunotherapy combines the destructive power of photodynamic therapy with the specificity of immunotherapy. But monoclonal antibodies bound to photosensitizers are large, and difficult to get deep into the tumor. Here, the authors attach a photosensitive dye to tiny “affibody” ligands designed to seek out EGFR, which is often overexpressed in glioblastoma. The affibody molecule brings the dye molecules into the cancer cells, and when it is exposed to near‐infrared wavelengths of light. It kills the cell. They showed that the EGFR‐affibody combined with the photoreactive dye selectively kills glioblastoma cells overexpressing EGFR in mice.

Glioblastoma (GBM) is a primary neuroepithelial tumor of the central nervous system, characterized by an extremely aggressive clinical phenotype. Patients with GBM have a poor prognosis and only 3–5% of them survive for more than 5 years. The current GBM treatment standards include maximal resection followed by radiotherapy with concomitant and adjuvant therapies. Despite these aggressive therapeutic regimens, the majority of patients suffer recurrence due to molecular heterogeneity of GBM. Consequently, a number of potential diagnostic, prognostic, and predictive biomarkers have been investigated. Some of them, such as IDH mutations, 1p19q deletion, MGMT promoter methylation, and EGFRvIII amplification are frequently tested in routine clinical practice. With the development of sequencing technology, detailed characterization of GBM molecular signatures has facilitated a more personalized therapeutic approach and contributed to the development of a new generation of anti-GBM therapies such as molecular inhibitors targeting growth factor receptors, vaccines, antibody-based drug conjugates, and more recently inhibitors blocking the immune checkpoints. In this article, we review the exciting progress towards elucidating the potential of current and novel GBM biomarkers and discuss their implications for clinical practice.