A trustworthy CpG nanoplatform for highly safe and efficient cancer photothermal combined immunotherapy.

Palladium nanosheets (Pd NSs) have recently attracted increasing research interest in the biomedical field due to their excellent near-infrared absorption, photothermal conversion capability and biocompatibility. However, the application of Pd NSs in immunotherapy has not been reported. Here, Pd NSs were used as the carriers of immunoadjuvant CpG ODNs for not only efficient delivery of CpG but also for enhancing the immunotherapeutic effects of CpG by the Pd NS-based photothermal therapy (PTT). Pd NSs had no influence on the immune system, and the prepared Pd-CpG nanocomposites, especially Pd(5)-CpG(PS), could significantly increase the uptake of CpG by immune cells and enhance the immunostimulatory activity of CpG in vitro and in vivo. With the combination of Pd(5)-CpG(PS) mediated PTT and immunotherapy, highly efficient tumor inhibition was achieved and the survival rate of the tumor-bearing mice was greatly increased depending on Pd(5)-CpG(PS) with safe near-infrared (NIR) irradiation (808 nm laser, 0.15 W cm-2). Importantly, the combination therapy induced tumor cell death and released tumor-associated antigens, which could be effectively taken up and presented by antigen presenting cells with the assistance of CpG, leading to increased TNF-α and IL-6 production and enhanced cytotoxic T lymphocyte (CTL) activity. This work provides a new paradigm of utilizing photothermal nanomaterials for safe and highly efficient cancer photothermal combined immunotherapy.

Liposomal CpG-ODN: An in vitro and in vivo study on macrophage subtypes responses, biodistribution and subsequent therapeutic efficacy in mice models of cancers.

CpG oligodeoxynucleotides (CpG-ODN), a common immune stimulator and vaccine adjuvant, was reported to switch Tumor Associated Macrophages (TAMs) from M2 to M1 phenotype inducing anti-tumor responses. Liposomes are of the successfully applied carriers for CpG-ODN. The aim of present study was design and preparation of a liposomal formulation containing phosphodiester CpG-ODN, evaluation of its effect on macrophages responses, and subsequent antitumor responses in mice. Liposomal formulations containing phosphodiester CpG-ODN or non-CpG-ODN were prepared and characterized. MTT reduction assay in four different cell lines, uptake, arginase and iNOS activity evaluation in macrophage cell lines, biodistribution study and therapeutic anti-tumor effects of formulations in mice bearing C26 colon carcinoma or B16F0 melanoma were carried out. The size of liposomes containing CpG-ODN was ~200 nm with the encapsulation efficiency of 33%. The iNOS activity assay showed high nitric oxide (NO) level in M2 phenotype of macrophage cell lines treated by liposomes containing CpG-ODN. In mice which received liposomes containing CpG-ODN as a monotherapy, maximum tumor growth delay with remarkable survival improvement was observed compared to control groups. Biodistribution study showed the accumulation of liposomal formulation in tumor micro-environment. In conclusion, considerable anti-tumor responses observed by liposomes containing CpG-ODN was due to enhanced delivery of CpG-ODN to immune cells and subsequent initiation of anti-tumoral immune responses.

Inhibition of cerebral vascular inflammation by brain endothelium-targeted oligodeoxynucleotide complex.

The present study generated a novel DNA complex to specifically target endothelial NF-κB to inhibit cerebral vascular inflammation. This DNA complex (GS24-NFκB) contains a DNA decoy which inhibits NF-κB activity, and a DNA aptamer (GS-24), a ligand of transferrin receptor (TfR), which allows for targeted delivery of the DNA decoy into cells. The results indicate that GS24-NFκB was successfully delivered into a murine brain-derived endothelial cell line, bEND5, and inhibited inflammatory responses induced by tumor necrosis factor α (TNF-α) or oxygen-glucose deprivation/re-oxygenation (OGD/R) via down-regulation of the nuclear NF-κB subunit, p65, as well as its downstream inflammatory cytokines, inter-cellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule (VCAM-1). The inhibitory effect of the GS24-NFκB was demonstrated by a significant reduction in TNF-α or OGD/R induced monocyte adhesion to the bEND5 cells after GS24-NFκB treatment. Intravenous (i.v.) injection of GS24-'NFκB (15mg/kg) was able to inhibit the levels of phoseph-p65 and VCAM-1 in brain endothelial cells in a mouse lipopolysaccharide (LPS)-induced inflammatory model in vivo. In conclusion, our approach using DNA nanotechnology for DNA decoy delivery could potentially be utilized for inhibition of inflammation in ischemic stroke and other neuro-inflammatory diseases affecting cerebral vasculature.

Refilling drug delivery depots through the blood.

Local drug delivery depots have significant clinical utility, but there is currently no noninvasive technique to refill these systems once their payload is exhausted. Inspired by the ability of nanotherapeutics to target specific tissues, we hypothesized that blood-borne drug payloads could be modified to home to and refill hydrogel drug delivery systems. To address this possibility, hydrogels were modified with oligodeoxynucleotides (ODNs) that provide a target for drug payloads in the form of free alginate strands carrying complementary ODNs. Coupling ODNs to alginate strands led to specific binding to complementary-ODN-carrying alginate gels in vitro and to injected gels in vivo. When coupled to a drug payload, sequence-targeted refilling of a delivery depot consisting of intratumor hydrogels completely abrogated tumor growth. These results suggest a new paradigm for nanotherapeutic drug delivery, and this concept is expected to have applications in refilling drug depots in cancer therapy, wound healing, and drug-eluting vascular grafts and stents.

Non-clinical safety studies of IMT504, a unique non-CpG oligonucleotide.

IMT504 is a non-CpG 24-mer oligodeoxynucleotide (ODN) with immunomodulatory as well as tissue repair activity. IMT504 has been previously proven to be effective in animal models of vaccine potency, chronic lymphocytic leukemia, tissue regeneration, and sepsis. Here, we assessed the safety, including pharmacokinetics and toxicity studies in rats and monkeys, of IMT504 in a single- or repeated-dose administration by the subcutaneous (SC) or intravenous (IV) routes. In rats, the maximum tolerated dose was determined to be 50 mg/kg when administered SC. Adverse effects at 50 mg/kg were mild and reversible liver injury, revealed as lobular inflammation, focal necrosis, and small changes in the transaminase profile. Dose-dependent splenomegaly and lymphoid hyperplasia, most probably associated with immune stimulation, were commonly observed. Rats and monkeys were also IV injected with a single dose of 10 or 3.5 mg/kg, and no adverse effects were observed. Rats injected IV with 10 mg/kg showed a transient increase in spleen weight, together with a slight increase in the marginal zone of the white pulp and in leukocyte count 2 days post-administration. In monkeys, this dosage caused slight changes in total serum complement and leukocyte count on day 14. No adverse effects were observed at 3.5 mg/kg IV in rats or monkeys. Therefore, this dose was defined as the "no observed adverse effect level" for this route. Furthermore, repeated-dose toxicity studies were performed in these species using 3.5 or 0.35 mg/kg/day IV for 6 weeks. A transient increase in the spleen and liver weight was observed at 3.5 mg/kg/day only in female rats. No changes in clotting time and activation of the alternative complement pathway were observed. The toxicity profile of IMT504 herein reported suggests a dose range in which IMT504 can be used safely in clinical trials.

Adjuvant activity of CpG-ODN formulated as a liquid crystal.

The adjuvants approved in human vaccine with recombinant/purified antigens induce weak cellular immune response and so the development of new adjuvant strategies is critical. CpG-ODN has successfully been used as an adjuvant (phase I-III clinical trials) but its bioavailability needs to be improved. We investigated the adjuvant ability of CpG-ODN formulated with a liquid crystal nanostructure of 6-O-ascorbyl palmitate (Coa-ASC16). Mice immunized with OVA/CpG-ODN/Coa-ASC16 elicited a potent specific IgG1, IgG2a, Th1 and Th17 cellular response without systemic adverse effects. These responses were superior to those induced by OVA/CpG-ODN (solution of OVA with CpG-ODN) and to those induced by the formulation OVA/CpG-ODN/Al(OH)3. Immunization with OVA/CpG-ODN/Coa-ASC16 resulted in a long-lasting cell-mediated immune response (at least 6.5 months). Furthermore, Coa-ASC16 alone allows a controlled release of CpG-ODN in vitro and induces local inflammatory response, independent of TLR4 signaling, characterized by an influx of neutrophils and Ly6C(high) monocytes and pro-inflammatory cytokines. Remarkably, the adjuvant capacity of CpG-ODN co-injected with Coa-ASC16 (OVA/CpG-ODN plus Coa-ASC16) was similar to the adjuvant activity of OVA/CpG-ODN, supporting the requirement for whole formulation to help CpG-ODN adjuvanticity. These results show the potential of this formulation, opening a new avenue for the development of better vaccines.

AS1411 aptamer tagged PLGA-lecithin-PEG nanoparticles for tumor cell targeting and drug delivery.

Liposomes and polymers are widely used drug carriers for controlled release since they offer many advantages like increased treatment effectiveness, reduced toxicity and are of biodegradable nature. In this work, anticancer drug-loaded PLGA-lecithin-PEG nanoparticles (NPs) were synthesized and were functionalized with AS1411 anti-nucleolin aptamers for site-specific targeting against tumor cells which over expresses nucleolin receptors. The particles were characterized by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The drug-loading efficiency, encapsulation efficiency and in vitro drug release studies were conducted using UV spectroscopy. Cytotoxicity studies were carried out in two different cancer cell lines, MCF-7 and GI-1 cells and two different normal cells, L929 cells and HMEC cells. Confocal microscopy and flowcytometry confirmed the cellular uptake of particles and targeted drug delivery. The morphology analysis of the NPs proved that the particles were smooth and spherical in shape with a size ranging from 60 to 110 nm. Drug-loading studies indicated that under the same drug loading, the aptamer-targeted NPs show enhanced cancer killing effect compared to the corresponding non-targeted NPs. In addition, the PLGA-lecithin-PEG NPs exhibited high encapsulation efficiency and superior sustained drug release than the drug loaded in plain PLGA NPs. The results confirmed that AS1411 aptamer-PLGA-lecithin-PEG NPs are potential carrier candidates for differential targeted drug delivery.

Solid-phase synthesis, thermal denaturation studies, nuclease resistance, and cellular uptake of (oligodeoxyribonucleoside)methylborane phosphine-DNA chimeras.

The major hurdle associated with utilizing oligodeoxyribonucleotides for therapeutic purposes is their poor delivery into cells coupled with high nuclease susceptibility. In an attempt to combine the nonionic nature and high nuclease stability of the P-C bond of methylphosphonates with the high membrane permeability, low toxicity, and improved gene silencing ability of borane phosphonates, we have focused our research on the relatively unexplored methylborane phosphine (Me-P-BH(3)) modification. This Article describes the automated solid-phase synthesis of mixed-backbone oligodeoxynucleotides (ODNs) consisting of methylborane phosphine and phosphate or thiophosphate linkages (16-mers). Nuclease stability assays show that methylborane phosphine ODNs are highly resistant to 5' and 3' exonucleases. When hybridized to a complementary strand, the ODN:RNA duplex was more stable than its corresponding ODN:DNA duplex. The binding affinity of ODN:RNA duplex increased at lower salt concentration and approached that of a native DNA:RNA duplex under conditions close to physiological saline, indicating that the Me-P-BH(3) linkage is positively charged. Cellular uptake measurements indicate that these ODNs are efficiently taken up by cells even when the strand is 13% modified. Treatment of HeLa cells and WM-239A cells with fluorescently labeled ODNs shows significant cytoplasmic fluorescence when viewed under a microscope. Our results suggest that methylborane phosphine ODNs may prove very valuable as potential candidates in antisense research and RNAi.

Trabedersen, a TGFbeta2-specific antisense oligonucleotide for the treatment of malignant gliomas and other tumors overexpressing TGFbeta2.

Trabedersen (AP-12009), which is being developed by Antisense Pharma GmbH, is a synthetic antisense oligodeoxynucleotide designed to block the production of TGFbeta2, a secreted protein that can exert protumor effects. Trabedersen is indicated for the treatment of malignant brain tumors and other solid tumors overexpressing TGFbeta2, such as those of the skin, pancreas and colon. Preclinical studies demonstrated that trabedersen reduced the secretion of TGFbeta2 in cultured tumor cells and exhibited antitumor activity ex vivo. It was also demonstrated that chronic intracerebral or intravascular administration of trabedersen did not cause life-threatening side effects in animals. This observation was confirmed in early clinical trials in patients with advanced cancer. In a phase IIb trial, improved survival was observed in patients with brain tumors who were intratumorally administered trabedersen, compared with patients receiving standard chemotherapy. However, this observation requires validation by an ongoing large-scale, phase III, randomized, controlled trial. Meanwhile, continued research on trabedersen should help to determine the roles of TGFbeta2 in cancer and also further the development of antisense technology.

Phase I trial of GTI-2040, oxaliplatin, and capecitabine in the treatment of advanced metastatic solid tumors: a California Cancer Consortium Study.

BACKGROUND: GTI-2040 is a 20-mer antisense oligonucleotide targeting the mRNA of ribonucleotide reductase M2. It was combined with oxaliplatin and capecitabine in a phase I trial in patients with advance solid tumors based on previous studies demonstrating potentiation of chemotherapy with ribonucleotide reductase inhibitors. METHODS: Patients at least 18 years of age with advanced incurable solid tumors and normal organ function as well as a Karnofsky performance status of > or =60% were eligible. One prior chemotherapy regimen for advanced disease or relapse within 12 months of adjuvant chemotherapy was required. Patients could have received prior fluoropyrimidines, including capecitabine, but not oxaliplatin. Treatment cycles were 21 days. In each cycle, GTI-2040 was given as a continuous intravenous infusion over 14 days, oxaliplatin as a 2-h intravenous infusion on day 1, and capecitabine orally twice a day for 14 days. In cycle 1 only, oxaliplatin and capecitabine were started on day 2 to allow ribonucleotide reductase mRNA levels to be measured with and without oxaliplatin and capecitabine. Doses were escalated in cohorts of three patients using a standard 3 + 3 design until the maximum tolerated dose was established, defined as no more than one first-cycle dose-limiting toxicity among six patients treated at a given dose level. RESULTS: The maximum tolerated dose was estimated to be the combination of GTI-2040 3 mg/kg per day for 14 days, capecitabine 600 mg/m(2) twice daily for 14 days, and oxaliplatin 100 mg/m(2) every 21 days. Dose-limiting toxicities were hematologic. GTI-2040 pharmacokinetics, obtained at steady-state on days 7 and 14, showed the high inter-patient variability previously reported. Two of six patients had stable disease at the maximum tolerated dose and one patient, with heavily pre-treated non-small cell lung cancer, had a partial response at a higher dose level. In samples from a limited number of patients, there was no clear decrease in ribonucleotide reductase expression in peripheral blood mononuclear cells during treatment. CONCLUSION: A combination of GTI-2040, capecitabine and oxaliplatin is feasible in patients with advanced solid tumors.