Radioiodinated hypericin: its biodistribution, necrosis avidity and therapeutic efficacy are influenced by formulation.

PURPOSE: To study whether formulation influences biodistribution, necrosis avidity and tumoricidal effects of the radioiodinated hypericin, a necrosis avid agent for a dual-targeting anticancer radiotherapy. METHODS: Iodine-123- and 131-labeled hypericin ((123)I-Hyp and (131)I-Hyp) were prepared with Iodogen as oxidant, and formulated in dimethyl sulfoxide (DMSO)/PEG400 (polyethylene glycol 400)/water (25/60/15, v/v/v) or DMSO/saline (20:80, v/v). The formulations with excessive Hyp were optically characterized. Biodistribution, necrosis avidity and tumoricidal effects were studied in rats (n = 42) without and with reperfused liver infarction and implanted rhabdomyosarcomas (R1). To induce tumor necrosis, R1-rats were pre-treated with a vascular disrupting agent. Magnetic resonance imaging, tissue-gamma counting, autoradiography and histology were used. RESULTS: The two formulations differed significantly in fluorescence and precipitation. (123)I-Hyp/Hyp in DMSO/PEG400/water exhibited high uptake in necrosis but lower concentration in the lung, spleen and liver (p < 0.01). Tumor volumes of 0.9 ± 0.3 cm(3) with high radioactivity (3.1 ± 0.3% ID/g) were detected 6 days post-treatment. By contrast, (131)I-Hyp/Hypin DMSO/saline showed low uptake in necrosis but high retention in the spleen and liver (p < 0.01). Tumor volumes reached 2.6 ± 0.7 cm(3) with low tracer accumulation (0.1 ± 0.04%ID/g). CONCLUSIONS: The formulation of radioiodinated hypericin/hypericin appears crucial for its physical property, biodistribution, necrosis avidity and tumoricidal effects.

A safety study on single intravenous dose of tetrachloro-diphenyl glycoluril [iodogen] dissolved in dimethyl sulphoxide (DMSO).

1. Iodogen (tetrachloro-diphenyl glycoluril) dissolved in DMSO (dimethyl sulphoxide) appears indispensable in radioiodination of hypericin for a new anticancer strategy. We studied the safety of intravenously administered iodogen/DMSO in mice (n = 132). 2. Median lethal dose (LD50) of iodogen/DMSO was determined with doses of 40.0, 50.0, 55.0, 60.0, 65.0 and 70.0 mg/kg. Next, toxicity of iodogen/DMSO at 30.0 mg/kg was evaluated using saline and DMSO as controls. Changes in behaviour, body weight and serum biochemistry were evaluated. Histopathology of lungs, heart, liver and kidney was performed. 3. LD50 values of iodogen/DMSO were 59.5 mg/kg (95% confidence limits (CI): 54.1-65.4 mg/kg) and 61.0 mg/kg (95%CI: 56.2-66.2 mg/kg) for female and male mice, respectively. Similar to that of control groups, no animal deaths were encountered after iodogen/DMSO administration at 30.0 mg/kg. Body weights over 24 h were not altered in all groups, but significantly higher in iodogen/DMSO and DMSO groups (p < 0.05) 14 d post-injection. Blood urea nitrogen and alkaline phosphatase increased (p < 0.05) in iodogen/DMSO group without clinical symptoms. No pathologies were found by gross and microscopic inspection. 4. A single dose of iodogen/DMSO up to 30.0 mg/kg, over 3000 times the dose in potential human applications, appears safe, with an LD50 doubling that dose in mice.

Lentiviral vector followed by protein immunisation breaks tolerance against the self-antigen Her1 and results in lung cancer immunotherapy.

BACKGROUND: Lung cancer remains a leading cause of cancer mortality, and so the aim of the present study was to develop a therapeutic vaccine protocol. METHODS: We constructed a lentiviral vector (LV) expressing the extracellular domain (ECD) of murine Her1, an antigen associated with poor prognosis in lung cancer. RESULTS: A single LV injection, followed by two Her1 protein boosts, was effective in reducing the metastatic burden of Lewis lung carcinoma in mice. The Her1 LV immunisation generated CD8+ T cells that recognised Her1 ECD presented by dendritic cells, and that also homed to Her1-expressing tumours. Protein boosting further increased the CD8+ T cell response and generated anti-Her1 antibodies; in the antibody response, Her1 LV priming increased Th1-dependent immunoglobulin G2c production. CONCLUSIONS: The ability of this vaccine protocol to break both T cell and B cell tolerance to a self-antigen likely explains its effectiveness.

HER1-ECD vaccination dispenses with emulsification to elicit HER1-specific anti-proliferative effects.

EGFR (HER1) highlights as one of the most relevant tumor associated antigen in epithelial malignant cells. Monoclonal antibodies and tyrosine kinase inhibitors against EGFR remain as the most advanced approaches in clinical trials. More recently, an active immunotherapy using the HER1 extracellular domain (ECD) adjuvated in very small size proteoliposomes (VSSP) and emulsified in Montanide ISA-51 demonstrated its strength to inhibit tumor cell line proliferation by arresting cells in G(0)/G(1) stage and induction of apoptosis. In this study, we present a simpler HER1-ECD-based formulation, which is lacking the oily component Montanide ISA-51. Generated antibodies following non-emulsive formulation immunization recognized membrane EGFR; avoid EGF and TGFalpha coupling to EGFR leading to a marked abrogation of EGFR phosphorylation levels. Non-emulsive formulation also arrests cell cycle in G(0)/G(1) stage, demonstrating it preserves previous formulation quality in a newer and simpler formulation.

Anti-EGFR activation, anti-proliferative and pro-apoptotic effects of polyclonal antibodies induced by EGFR-based cancer vaccine.

Up to now clinical experiences focusing EGF receptor, an attractive target for cancer therapy, have been limited to passive therapies, suggesting that therapeutic cancer vaccines inducing anti-epidermal growth factor receptor (EGFR) antibodies could also work. Here, the humoral immune response induced in mice with a vaccine formulation containing the human EGFR-extracellular domain and very small-sized proteoliposomes (VSSP), a novel nanoparticulated adjuvant was assessed. In vaccinated mice sera average of the specific polyclonal antibodies (PAb) titers was 10(-5). Anti-EGFR PAb were able to bind EGFR+ tumor cell lines, expressing different levels of the molecule. Noteworthy, the presence of Cetuximab only partially inhibited the vaccine-induced antibodies binding to H125 cells. Anti-EGFR PAb abrogated ligands-dependent EGFR phosphorylation, provoking tumor cells apoptosis. The described EGFR-based vaccine might be a superior therapeutic approach for patients with EGFR+ tumors.