Search Results (59)

Sarcomas are very complex and clinically challenging mesenchymal tumors. Although the standard therapeutic approach has improved the 5-year survival rate, many patients experience local relapses and/or distant metastases. To improve patient outcome, new strategies need to be investigated. Immunotoxins (ITs) based on rRNA N-glycosylases (also named ribosome-inactivating proteins, RIPs) are promising tools for cancer therapy because, by combining rRNA-glycosylase’s high cytotoxicity with carrier selectivity, they can specifically eliminate target neoplastic cells. In the last few years, 3D models have been extensively used in cancer research, particularly for target-specific drug screening. This study aimed to evaluate the possibility of utilizing ribosome-inactivating protein (RIP)-containing ITs to selectively target TfR1-, EGFR1- and Her2-expressing sarcoma adherent cells (ACs), spheroids (SSs) and organoids (ORs). To compare Its’ efficacy and ability to induce apoptosis, we performed dose–response viability and caspase 3/7 activation assays on rhabdomyosarcoma and osteosarcoma ACs, SSs and ORs treated with Tf-IT, αEGFR1-IT and αHer2-IT. Our results indicate that, compared to the corresponding unconjugated RIPs, all ITs showed increased cytotoxicity in sarcoma ACs. Despite the increased complexity characterizing 3D models, the higher IC₅₀ differences between ITs and unconjugated RIPs were obtained in ORs, which appeared more resistant to the nonspecific killing of the RIPs than either the ACs or SSs, thus augmenting the therapeutic window between unconjugated and conjugated RIPs. IT induced a more delayed apoptosis in 3D compared to 2D models. Our results provide essential outcomes for the potential use of these RIP-based ITs as a therapeutic strategy to treat sarcoma. Full article

Background: The ⁸⁹Zr radioisotope is increasingly vital in positron emission tomography (PET), especially immuno-PET, due to its long half-life of 78.4 h, allowing extended tracking of biological processes. This makes it particularly suitable for researching medicines with slow pharmacokinetics and enhances the precision of molecular imaging, especially in oncology. Despite zirconium’s potential for skeletal accumulation, effective chelation with agents like deferoxamine (DFO) enables high-resolution imaging of antigen-specific tumours, such as HER2-positive breast cancer, offering insights into tumour biology and treatment response. Methods: ⁸⁹Zr was produced at the ACSI TR-19 cyclotron via ⁸⁹Y(p,n)⁸⁹Zr reaction. Natural yttrium foils (250 μm) were irradiated with 12.9 MeV protons on target, with 100 μA·h. An HER2-targeting affibody was synthesized and conjugated with p-NCS-Bz-DFO (1:4 mass ratio) at 37 °C for 60 min (pH 9.2 ± 0.2), then purified on a PD-10 column. Radiolabelling was performed with [⁸⁹Zr]Zr-oxalate at pH ranging from 7.0 to 9.0, with concentrations from 110 to 460 MBq/mL. Results: Final activity reached 2.95 ± 0.31 GBq/batch (EOB corrected), with ≥ 99.9% radionuclide and ≥95% radiochemical purities. The anti-HER2 affibody was successfully radiolabelled with ⁸⁹Zr, resulting in a radiochemical purity of over 85% with molar activity of 26.5 ± 4.4 and 11.45 MBq/nmol at pH 7.0–7.5. In vitro tests on BT-474 and MCF-7 cell lines confirmed high uptake in HER2-positive cells, validating specificity and stability. Conclusions: The successful synthesis and labelling of the [⁸⁹Zr]Zr-p-NCS-Bz-DFO-anti-HER2 affibody are promising achievements for its further application in targeted immuno-PET imaging for HER2-positive malignancies. Further in vivo studies are needed to support its clinical translation. Full article

(1) Background/Objectives: Primary and secondary brain tumours often hold devastating prognoses and low survival rates despite the application of maximal neurosurgical resection, and state-of-the-art radiotherapy and chemotherapy. One limiting factor in their management is that several antineoplastic agents are unable to cross the blood–brain barrier (BBB) to reach the tumour microenvironment. Nanomedicine could hold the potential to become an effective means of drug delivery to overcome previous hurdles towards effective neuro-oncological treatments. (2) Methods: A scoping review following the PRISMA-ScR guidelines and checklist was conducted using key terms input into PubMed to find articles that reflect emerging trends in the utilisation of nanomedicine in drug delivery for primary and secondary brain tumours. (3) Results: The review highlights various strategies by which different nanoparticles can be exploited to bypass the BBB; we provide a synthesis of the literature on the ongoing contributions to therapeutic protocols based on chemotherapy, immunotherapy, focused ultrasound, radiotherapy/radiosurgery, and radio-immunotherapy. (4) Conclusions: The emerging trends summarised in this scoping review indicate encouraging advantageous properties of nanoparticles as potential effective drug delivery mechanisms; however, there are still nanotoxicity issues that largely remain to be addressed before the translation of these innovations from laboratory to clinical practice. Full article

Monoclonal antibodies (mAbs) have completely changed the face of oncology over the last 50 years, and they have contributed to a major breakthrough in terms of cancer therapy. Esophageal and gastric cancers, the eighth and fifth most commonly diagnosed types of cancer worldwide, respectively, have lately, been managed more effectively, with the introduction of new therapeutic treatment strategies, especially mAbs. Combination treatments and new molecules have changed the face of the disease, while more therapies are getting approved on a daily basis. This review aims to analyse the major up-to-date clinical trials using mAbs and immunotherapy for the treatment of advanced gastro-esophageal cancers. Full article

The present review provides a detailed and comprehensive discussion on antibody–drug conjugates (ADCs) as an evolving new modality in the current therapeutic landscape of malignant diseases. The principle concepts of targeted delivery of highly toxic agents forsaken as stand-alone drugs are examined in detail, along with the biochemical and technological tools for their successful implementation. An extensive analysis of ADCs’ major components is conducted in parallel with their function and impact on the stability, efficacy, safety, and resistance profiles of the immunoconjugates. The scope of the article covers the major classes of currently validated natural compounds used as payloads, with an emphasis on their structural and mechanistic features, natural origin, and distribution. Future perspectives in ADCs’ design are thoroughly explored, addressing their inherent or emerging challenges and limitations. The survey also provides a comprehensive overview of the molecular rationale for active tumor targeting of ADC-based platforms, exploring the cellular biology and clinical relevance of validated tumor markers used as a “homing” mechanism in both hematological and solid tumor malignancies. Full article

Preliminary studies on a radioactive antibody against the neural cell adhesion molecule (NCAM) demonstrated a significant accumulation of [¹³¹I]I-ERIC1 in neuroblastoma tumor cells in mice. This study aims to validate the therapeutic efficacy and potential adverse effects of these radioactive immunoconjugates (RICs) in neuroblastoma-bearing mice. To determine the highest tolerated dose, healthy SCID mice received 1 to 22 MBq of [¹³¹I]I-ERIC1, with the survival time measured. Tumor response was evaluated by administering 0.8 to 22 MBq of [¹³¹I]I-ERIC1 to neuroblastoma-bearing mice and assessing tumor size and systemic toxicity through body weight, blood counts, and survival. It was observed that doses up to approximately 3 MBq per animal (150 MBq/kg) were well tolerated, whereas higher doses resulted in systemic toxicity and death. The neuroblastomas exhibited a dose-dependent response, with optimal therapeutic efficacy achieved at 1.8–2.5 MBq per animal (90–125 MBq/kg), significantly extending survival by a factor of five. The antibody ERIC1 is a promising vehicle for the transport of beta emitters into NCAM-positive tumor tissue. An optimal dosage of the [¹³¹I]I-ERIC1 antibody can be established with a balance of tumor-static effects and adverse effects, resulting in a marked extension of survival time. Full article

Introduction: Hairy-cell leukemia (HCL) is a rare B-cell chronic lymphoproliferative disorder (B-CLPD), whose favorable prognosis has changed with the use of purine nucleoside analogs (PNAs), such as cladribine (CDA) or pentostatin (P). However, some patients eventually relapse and over time HCL becomes resistant to chemotherapy. Many discoveries have been made in the pathophysiology of HCL during the last decade, especially in genomics, with the identification of the BRAF^V600E mutation and cellular biology, including the importance of signaling pathways as well as tumor microenvironment. All of these new developments led to targeted treatments, especially BRAF inhibitors (BRAFis), MEK inhibitors (MEKis), Bruton’s tyrosine kinase (BTK) inhibitors (BTKis) and recombinant anti-CD22 immunoconjugates. Results: The following major changes or additions were introduced in these updated guidelines: the clinical relevance of the changes in the classification of splenic B-cell lymphomas and leukemias; the increasingly important diagnostic role of BRAF^V600E mutation; and the prognostic role of the immunoglobulin (IG) variable (V) heavy chain (H) (IGHV) mutational status and repertory. We also wish to insist on the specific involvement of bones, skin, brain and/or cerebrospinal fluid (CSF) of the disease at diagnosis or during the follow-up, the novel targeted drugs (BRAFi and MEKi) used for HCL treatment, and the increasing role of minimal residual disease (MRD) assessment. Conclusion: Here we present recommendations for the diagnosis of HCL, treatment in first line and in relapsed/refractory patients as well as for HCL-like disorders including HCL variant (HCL-V)/splenic B-cell lymphomas/leukemias with prominent nucleoli (SBLPN) and splenic diffuse red pulp lymphoma (SDRPL). Full article

Acidosis is an important immunosuppressive mechanism that leads to tumor growth. Therefore, we investigated the neutralization of tumor acidity to improve immunotherapy response. L-DOS47, a new targeted urease immunoconjugate designed to neutralize tumor acidity, has been well tolerated in phase I/IIa trials. L-DOS47 binds to CEACAM6, a cell-surface protein that is highly expressed in gastrointestinal cancers, allowing urease to cleave endogenous urea into two NH4+ and one CO₂, thereby raising local pH. To test the synergetic effect of neutralizing tumor acidity with immunotherapy, we developed a pancreatic orthotopic murine tumor model (KPC961) expressing human CEACAM6. Using chemical exchange saturation transfer–magnetic resonance imaging (CEST-MRI) to measure the tumor extracellular pH (pHe), we confirmed that L-DOS47 raises the tumor pHe from 4 h to 96 h post injection in acidic tumors (average increase of 0.13 units). Additional studies showed that combining L-DOS47 with anti-PD1 significantly increases the efficacy of the anti-PD1 monotherapy, reducing tumor growth for up to 4 weeks. Full article

Photo-immunotherapy uses antibodies conjugated to photosensitizers to produce nanostructured constructs endowed with targeting properties and photo-inactivation capabilities towards tumor cells. The superficial receptor density on cancer cells is considered a determining factor for the efficacy of the photodynamic treatment. In this work, we propose the use of a photoactive conjugate that consists of the clinical grade PD-L1-binding monoclonal antibody Atezolizumab, covalently linked to either the well-known photosensitizer eosin or the fluorescent probe Alexa647. Using single-molecule localization microscopy (direct stochastic optical reconstruction microscopy, dSTORM), and an anti-PD-L1 monoclonal antibody labelled with Alexa647, we quantified the density of PD-L1 receptors exposed on the cell surface in two human non-small-cell lung cancer lines (H322 and A549) expressing PD-L1 to a different level. We then investigated if this value correlates with the effectiveness of the photodynamic treatment. The photodynamic treatment of H322 and A549 with the photo-immunoconjugate demonstrated its potential for PDT treatments, but the efficacy did not correlate with the PD-L1 expression levels. Our results provide additional evidence that receptor density does not determine a priori the level of photo-induced cell death. Full article

We are developing cytotoxic immunoconjugates (CICs) targeting the envelope protein (Env) of the Human Immunodeficiency Virus, type 1 (HIV) to purge the persistent reservoirs of viral infection. We have previously studied the ability of multiple monoclonal antibodies (mAbs) to deliver CICs to an HIV-infected cell. We have found that CICs targeted to the membrane-spanning gp41 domain of Env are most efficacious, in part because their killing is enhanced in the presence of soluble CD4. The ability of a mAb to deliver a CIC does not correlate with its ability to neutralize nor mediate Ab-dependent cellular cytotoxicity. In the current study, we seek to define the most effective anti-gp41 mAbs for delivering CICs to HIV-infected cells. To do this, we have evaluated a panel of human anti-gp41 mAbs for their ability to bind and kill two different Env-expressing cell lines: persistently infected H9/NL4-3 and constitutively transfected HEK293/92UG. We measured the binding and cytotoxicity of each mAb in the presence and absence of soluble CD4. We found that mAbs to the immunodominant helix-loop-helix region (ID-loop) of gp41 are most effective, whereas neutralizing mAbs to the fusion peptide, gp120/gp41 interface, and the membrane proximal external region (MPER) are relatively ineffective at delivering CICs. There was only a weak correlation between antigen exposure and killing activity. The results show that the ability to deliver an effective IC and neutralization are distinct functions of mAbs. Full article

The simultaneous detection of atherosclerotic cardiovascular disease (ACSVD) biomarkers was recently of great scientific interest. In this work, magnetic beads-based immunosensors for the simultaneous detection of low density lipoprotein (LDL) and malondialdehyde-modified low density lipoprotein (MDA-LDL) were presented. The approach proposed was based on the formation of two types of specific immunoconjugates consisting of monoclonal antibodies: anti-LDL or anti-MDA-LDL, together with redox active molecules: ferrocene and anthraquinone, respectively, coated on magnetic beads (MBs). The decrease in redox agent current in the concentration range: 0.001–1.0 ng/mL for LDL and 0.01–10.0 ng/mL for MDA-LDL, registered by square wave voltammetry (SWV), was observed upon the creation of complex between LDL or MDA-LDL and appropriate immunoconjugates. The detection limits of 0.2 ng/mL for LDL and 0.1 ng/mL for MDA-LDL were estimated. Moreover, the results of selectivity against the possible interferents were good, as human serum albumin (HSA) and high density lipoprotein (HDL), stability and recovery studies demonstrated the potential of platform proposed for early prognosis and diagnosis of ASCVD. Full article

The availability of several bioorthogonal reactions that can proceed selectively and efficiently under physiologically relevant conditions has garnered the interest of biochemists and organic chemists alike. Bioorthogonal cleavage reactions represent the latest innovation in click chemistry. Here, we employed the Staudinger ligation reaction to release radioactivity from immunoconjugates, improving target-to-background ratios. In this proof-of-concept study, model systems, including the anti-HER2 antibody trastuzumab, radioisotope I-131, and a newly synthesized bifunctional phosphine, were used. Staudinger ligation occurred when biocompatible N-glycosyl azides reacted with this radiolabeled immunoconjugate, leading to cleavage of the radioactive label from the molecule. We demonstrated this click cleavage in vitro and in vivo. Biodistribution studies in tumor models showed that radioactivity was eliminated from the bloodstream, thereby improving tumor-to-blood ratios. SPECT imaging revealed that tumors could be visualized with enhanced clarity. Our simple approach represents a novel application of bioorthogonal click chemistry in the development of antibody-based theranostics. Full article

Cetuximab is a monoclonal antibody blocking the epidermal growth factor receptor (EGFR) in metastatic colorectal cancer (mCRC). However, cetuximab treatment has no clinical benefits in patients affected by mCRC with KRAS mutation or in the presence of constitutive activation of signalling pathways acting downstream of the EGFR. The aim of this study was to improve cetuximab’s therapeutic action by conjugating cetuximab with the type 1 ribosome inactivating protein (RIP) quinoin isolated from quinoa seeds. A chemical conjugation strategy based on the use of heterobifunctional reagent succinimidyl 3-(2-pyridyldithio)propionate (SPDP) was applied to obtain the antibody-type 1 RIP chimeric immunoconjugate. The immunotoxin was then purified by chromatographic technique, and its enzymatic action was evaluated compared to quinoin alone. Functional assays were performed to test the cytotoxic action of the quinoin cetuximab immunoconjugate against the cetuximab-resistant GEO-CR cells. The novel quinoin cetuximab immunoconjugate showed a significant dose-dependent cytotoxicity towards GEO-CR cells, achieving IC₅₀ values of 27.7 nM (~5.0 μg/mL) at 72 h compared to cetuximab (IC₅₀ = 176.7 nM) or quinoin (IC₅₀ = 149.3 nM) alone assayed in equimolar amounts. These results support the therapeutic potential of quinoin cetuximab immunoconjugate for the EGFR targeted therapy, providing a promising candidate for further development towards clinical use in the treatment of cetuximab-resistant metastatic colorectal cancer. Full article

The development of ⁶⁴Cu-based immuno-PET radiotracers requires the use of copper-specific bifunctional chelators (BFCs) that contain functional groups allowing both convenient bioconjugation and stable copper complexes to limit in vivo bioreduction, transmetallation and/or transchelation. The excellent in vivo kinetic inertness of the pentaazamacrocyclic [⁶⁴Cu]Cu-15-5 complex prompted us to investigate its potential for the ⁶⁴Cu-labelling of monoclonal antibodies (mAbs), compared with the well-known NODAGA and DOTA chelators. To this end, three NODAGA, DOTA and 15-5-derived BFCs, containing a pendant azadibenzocyclooctyne moiety, were synthesised and a robust methodology was determined to form covalent bonds between them and azide-functionalised trastuzumab, an anti-HER2 mAb, using strain-promoted azide-alkyne cycloaddition. Unlike the DOTA derivative, the NODAGA- and 15-5-mAb conjugates were radiolabelled with ⁶⁴Cu, obtaining excellent radiochemical yields, under mild conditions. Although all the radioimmunoconjugates showed excellent stability in PBS or mouse serum, [⁶⁴Cu]Cu-15-5- and [⁶⁴Cu]Cu-NODAGA-trastuzumab presented higher resistance to transchelation when challenged by EDTA. Finally, the immunoreactive fraction of the radioimmunoconjugates (88–94%) was determined in HER-2 positive BT474 human breast cancer cells, confirming that the bioconjugation and radiolabelling processes implemented had no significant impact on antigen recognition. Full article

⁸⁹Zr represents a highly favorable positron emitter for application in immuno-PET (Positron Emission Tomography) imaging. Clinically, the ⁸⁹Zr⁴⁺ ion is introduced into antibodies by complexation with desferrioxamine B. However, producing complexes of limited kinetic inertness. Therefore, several new chelators for ⁸⁹Zr introduction have been developed over the last years. Of these, the direct comparison of the most relevant ones for clinical translation, DFO* and 3,4,3-(LI-1,2-HOPO), is still missing. Thus, we directly compared DFO with DFO* and 3,4,3-(LI-1,2-HOPO) immunoconjugates to identify the most suitable agent stable ⁸⁹Zr-complexation. The chelators were introduced into cetuximab, and an optical analysis method was developed, enabling the efficient quantification of derivatization sites per protein. The cetuximab conjugates were efficiently obtained and radiolabeled with ⁸⁹Zr at 37 °C within 30 min, giving the [⁸⁹Zr]Zr-cetuximab derivatives in high radiochemical yields and purities of >99% as well as specific activities of 50 MBq/mg. The immunoreactive fraction of all ⁸⁹Zr-labeled cetuximab derivatives was determined to be in the range of 86.5–88.1%. In vivo PET imaging and ex vivo biodistribution studies in tumor-bearing animals revealed a comparable and significantly higher kinetic inertness for both [⁸⁹Zr]Zr-3,4,3-(LI-1,2-HOPO)-cetuximab and [⁸⁹Zr]Zr-DFO*-cetuximab, compared to [⁸⁹Zr]Zr-DFO-cetuximab. Of these, [⁸⁹Zr]Zr-DFO*-cetuximab showed a considerably more favorable pharmacokinetic profile with significantly lower liver and spleen retention than [⁸⁹Zr]Zr-3,4,3-(LI-1,2-HOPO)-cetuximab. Since [⁸⁹Zr]Zr-DFO* demonstrates a very high kinetic inertness, paired with a highly favorable pharmacokinetic profile of the resulting antibody conjugate, DFO* currently represents the most suitable chelator candidate for stable ⁸⁹Zr-radiolabeling of antibodies and clinical translation. Full article