Systemic delivery of siRNA specific to tumor mediated by atelocollagen: Combined therapy using siRNA targeting Bcl‐xL and cisplatin against prostate cancer

Abstract

The largest obstacle to the effective use of short interfering RNA (siRNA) in an animal body is the ability to deliver it to the target tissue. Here we showed a systemic delivery method of siRNA specific to pregrown solid tumors via atelocollagen. Atelocollagen facilitated the selective uptake of siRNA into the tumors when an siRNA/atelocollagen complex was administered intravenously to mice. We chose a Bcl‐xL protein as a model target to prove the therapeutic efficacy of the atelocollagen‐mediated method. Bcl‐xL acts as an anti‐apoptotic factor, which is overexpressed in many cancers, including prostate cancer. One of the four designed siRNAs to human Bcl‐xL potently inhibited the expression of Bcl‐xL by the PC‐3 human prostate cancer cell line in vitro, leading to cell apoptosis. Intravenous injections for3 consecutive days (siRNA, 100 μg/injection per day as a complex with atelocollagen) effectively downregulated Bcl‐xL expression in the PC‐3 xenograft. We administered four series of 3 consecutive days of intravenous injections each, for a total of 12 injections, which significantly inhibited tumor growth when the treatment was combined with cisplatin (2 mg/kg). Local injection of Bcl‐xL siRNA also potently inhibited tumor growth. All of the tumors treated with Bcl‐xL siRNA/atelocollagen complex via both intravenous and intratumoral injection showed terminal deoxynucleotidyl transferase‐mediated dUTP nick‐end labeling‐positive apoptosis. There were no severe side effects such as interferon‐α induction and liver or renal damage in mice. Our results indicate that systemic delivery of siRNA via atelocollagen, which specifically targets tumors, is safe and feasible for cancer therapy. © 2009 UICC

The Metastasis-Associated microRNA miR-516a-3p Is a Novel Therapeutic Target for Inhibiting Peritoneal Dissemination of Human Scirrhous Gastric Cancer

“…First, synthetic miRNA instead of the plasmid vector should be examined; second, a systemic delivery system of synthetic miRNA specific to tumors should be developed. Toward these ends we have acquired promising results, because we already have much knowledge about how to systemically deliver synthetic small RNA molecules, that is, siRNA, specifically to tumors (22). The systemic therapeutic effect by the synthetic double-stranded RNA mimicking miR-516a-3p complexed with atelocollagen will be described elsewhere in the near future.…”

“…On the next day, the cells were washed once with serum-free RPMI 1640. Cell proliferation was monitored with a cell counting kit (Dojin) as reported previously (22). Migration and invasion analysis was performed with BD BioCoat Angiogenesis System-Endothelial Cell Migration and BD BioCoat Fluoroblok Tumor Invasion System (BD Biosciences) according to the manufacturer's instructions.…”

“…The analysis was performed according to our previous reports (22,(26)(27)(28). The following primary antibodies were used (Cell Signaling Japan): rabbit antihuman Wnt3a antibody, rabbit anti-human Wnt5a antibody, rabbit antihuman b-catenin antibody, a-tubulin, mouse anti-human a-tubulin antibody, and mouse antihuman histone H3 antibody, respectively.…”

MicroRNAs Associated with Epithelial-Mesenchymal Transition Can Be Targeted to Inhibit Peritoneal Dissemination of Human Scirrhous Gastric Cancers

“…8a). A biomaterial, atelocollagen (Koken) acts to deliver synthetic miRNA molecules specific to the 58As9 orthotopic tumors via intravenous injections, as we or the other group reported previously in the case of siRNA/miRNA delivery [21, 22, 36]. On day 20 (at the end point of the therapy), all of the mice were sacrificed, and the primary tumor tissues were excised.…”

Special delivery: targeted therapy with small RNAs

“…Although these particles have not been modified to target tumors, passive targeting due to the enhanced permeability and retention effect, causes the selective accumulation within the cancerous tissues as shown in several studies with tumor xenografts. 23,[37][38][39] Initial studies indicated that atelocollagen particles could be administered safely without induction of cytokines or observed toxicity to the tissues.…”