Lack of efficacy of Doxil® in TNF-α-based isolated limb perfusion in sarcoma-bearing rats

textabstractHere we show that Doxil® has minimal antitumour activity in the isolated limb perfusion (ILP) setting and its activity was not enhanced by the addition of tumour necrosis factor (TNF). Doxil® accumulation in tumour tissue was low and also not augmented by TNF. In contrast, activity of free conventional doxorubicin was enhanced by TNF. We conclude that application of Doxil® in a TNF-based ILP is not a useful alternative to free conventional doxorubicin or melphalan

Targeting of angiogenic endothelial cells at sites of inflammation by dexamethasone phosphate-containing RGD peptide liposomes inhibits experimental arthritis

Objective. To investigate whether RGD peptide-exposing long circulating polyethylene glycol (PEG) liposomes (RGD-PEG-L) targeted to alpha v beta 3 integrins expressed on angiogenic vascular endothelial cells (VECs) are able to bind VECs at sites of inflammation and whether such liposomes containing dexamethasone phosphate (DEXP) can be used as carriers to interfere with the development of experimental arthritis. Methods. Binding and internalization of RGDPEG-L were studied by fluorescence-activated cell sorting and confocal microscopy using fluorescently labeled liposomes. Radiolabeled liposomes were used to test in vivo pharmacokinetics and inflammation site targeting in lipopolysaccharide (LPS)-induced inflammation and adjuvant-induced arthritis (AIA) in rats. In vivo inflammation targeting was visualized by intravital microscopy using fluorescently labeled RGD-PEG-L. Therapeutic efficacy of DEXP-encapsulating RGD-PEG-L compared with nontargeted liposomes was evaluated in rats with AIA. Results. RGD-PEG-L bound to and were taken up by proliferating human VECs in vitro. In vivo, increased targeting of radiolabeled RGD-PEG-L to areas of LPS-induced inflammation in rats was observed. Specific association with the blood vessel wall at the site of inflammation was confirmed by intravital microscopy. One single intravenous injection of DEXP encapsulated in RGD-PEG-L resulted in a strong and long-lasting antiarthritic effect in rat AIA. Conclusion. RGD-targeted PEG liposomes represent an endothelial cell-specific drug delivery system that targets VECs at sites of inflammation. Use of these liposomes to deliver DEXP to VECs at arthritis-affected sites proved efficacious in rat adjuvant arthritis. These data indicate that VECs have an essential role in the inflammation process and suggest the possibility of using VEC targeting for therapeutic intervention in inflammatory processes such as arthritis

Targeting melanoma with immunoliposomes coupled to anti-MAGE A1 TCR-like single-chain antibody

Mesha Saeed,1 Mandy van Brakel,2 Sara Zalba,1 Erik Schooten,2 Joost AP Rens,1 Gerben A Koning,1,† Reno Debets,2 Timo LM ten Hagen1 1Laboratory of Experimental Surgical Oncology, Section Surgical Oncology, Department of Surgery, Erasmus MC, Rotterdam, the Netherlands; 2Laboratory of Tumor Immunology, Department of Medical Oncology, Erasmus MC Cancer Institute, Rotterdam, the Netherlands †Dr Gerben A Koning passed away on December 29, 2015 Abstract: Therapy of melanoma using T-cells with genetically introduced T-cell receptors (TCRs) directed against a tumor-selective cancer testis antigen (CTA) NY-ESO1 demonstrated clear antitumor responses in patients without side effects. Here, we exploited the concept of TCR-mediated targeting through introduction of single-chain variable fragment (scFv) antibodies that mimic TCRs in binding major histocompatibility complex-restricted CTA. We produced scFv antibodies directed against Melanoma AntiGEn A1 (MAGE A1) presented by human leukocyte antigen A1 (HLA-A1), in short M1/A1, and coupled these TCR-like antibodies to liposomes to achieve specific melanoma targeting. Two anti-M1/A1 antibodies with different ligand-binding affinities were derived from a phage-display library and reformatted into scFvs with an added cysteine at their carboxyl termini. Protein production conditions, ie, bacterial strain, temperature, time, and compartments, were optimized, and following production, scFv proteins were purified by immobilized metal ion affinity chromatography. Batches of pure scFvs were validated for specific binding to M1/A1-positive B-cells by flow cytometry. Coupling of scFvs to liposomes was conducted by employing different conditions, and an optimized procedure was achieved. In vitro experiments with immunoliposomes demonstrated binding of M1/A1-positive B-cells as well as M1/A1-positive melanoma cells and internalization by these cells using flow cytometry and confocal microscopy. Notably, the scFv with nonenhanced affinity of M1/A1, but not the one with enhanced affinity, was exclusively bound to and internalized by melanoma tumor cells expressing M1/A1. Taken together, antigen-mediated targeting of tumor cells as well as promoting internalization of nanoparticles by these tumor cells is mediated by TCR-like scFv and can contribute to melanoma-specific targeting. Keywords: cancer, immunotherapy, nanoparticles, cancer testis antigens, HLA-A1 targetin

Balloon catheter hypoxic pelvic perfusion with mitomycin C and melphalan for locally advanced tumours in the pelvic region: A phase I-II trial

Aims: To investigate the feasibility of hypoxic pelvic perfusion (HPP), using balloon catheter techniques as treatment modality for locally advanced pelvic malignancies. Methods: In a phase I-II study, 16 patients with various non-resectabte pelvic tumours were treated with two HIPP with MMC and melphatan, followed by radiotherapy (25 Gy) and surgical resection if feasible. Toxicity and procedure related complications were documented. Tumour responses were assessed by MRI or CT. Pain reductive effects were assessed by evaluation of pain registration forms. Results: HIPP resulted in augmented regional drug concentrations with relatively low systemic levels. Some severe systemic toxicity was observed. One procedure related death occurred. Pain reduction effects were short-lived. Ten patients had radiological NC, two PD and one PR. In 11 patients surgical resection was performed, which was microscopically radical in six cases. Mean survival was 26.8 months (range 1-86). Conclusion: The seemingly favorable pharmacokinetic profiles observed with HIPP in this and other studies can still lead to severe systemic toxicity. In terms of survival, local (re-)recurrence and pain reduction there seems no benefit of addition of HIPP to pre-operative radiotherapy. HPP with MMC and melphalan, does not seem a therapeutic option in patients with locally advanced pelvic tumours. (c) 2005 Published by Elsevier Ltd