Systemic delivery of Eg5 shRNA-expressing plasmids using PEGylated DC-Chol/DOPE cationic liposome: Long-term silencing and anticancer effects in vivo.

Duration of gene silencing due to the short-term silencing effects induced by exogenous siRNA have limited the therapeutic applications of RNAi and the development of RNAi-based therapeutics. We here generated Eg5 shRNA-expressing plasmids using the inverted terminal repeats (ITRs) sequences to produce Eg5 hairpin RNA under the control of U6 promoter. Using PEGylated DC-Chol/DOPE cationic liposomes, we demonstrated that a single systemic administration of Eg5 shRNA-expressing plasmid/liposome lipoplexes induced the long-term Eg5 silencing in the tumor sites of tumor-bearing mice, and ultimately lead to more sustained anticancer effects than standard synthetic siEg5/liposome lipoplexes. This non-viral Eg5 shRNA expression system had no risk of immunogenicity anticipated in the use of viral vectors, and could reduce the potential of off-target effects by scaling down the administration dose of RNAi therapeutics in patient. Therefore, the sustainable shRNA expression properties in the tumor sites suggest an efficient strategy to overcome the limitations caused by chemically synthesized siRNA methods such as short-term silencing effects and off-target effects. Herein, this study provides a non-viral silencing strategy for inducing long-term Eg5 silencing in vivo and suggests the great potential of Eg5 shRNA-expressing lipoplexes as a DNA-based RNAi therapeutics for cancer treatment.

Cancer peptide vaccine therapy developed from oncoantigens identified through genome-wide expression profile analysis for bladder cancer.

OBJECTIVE: The field of cancer vaccine therapy is currently expected to become the fourth option in the treatment of cancer after surgery, chemotherapy and radiation therapy. We developed a novel cancer peptide vaccine therapy for bladder cancer through a genome-wide expression profile analysis. METHODS: Among a number of oncoproteins that are transactivated in cancer cells, we focused on M phase phosphoprotein 1 and DEP domain containing 1, both of which are cancer-testis antigens playing critical roles in the growth of bladder cancer cells, as candidate molecules for the development of drugs for bladder cancer. In an attempt to identify the peptide epitope from these oncoantigens, we conducted a clinical trial using these peptides for patients with advanced bladder cancer. RESULTS: We identified HLA-A24-restricted peptide epitopes corresponding to parts of M phase phosphoprotein 1 and DEP domain containing 1 proteins, which could induce peptide-specific cytotoxic T lymphocytes. Using these peptides, we found that M phase phosphoprotein 1- and DEP domain containing 1-derived peptide vaccines could be well tolerated without any serious adverse events, and effectively induced peptide-specific cytotoxic T lymphocytes in vivo. CONCLUSIONS: The novel approach adopted in the treatment with peptide vaccines is considered to be a promising therapy for bladder cancer.

Kinesin motor domain of Leishmania donovani as a future vaccine candidate.

Visceral leishmaniasis (VL) is one of the important parasitic diseases, with approximately 350 million people at risk. Due to the nonavailability of an ideal drug, development of a safe, effective, and affordable vaccine could be a solution for control and prevention of this disease. The present study was carried out to examine the immunological potential of kinesin protein from the microtubule locus of Leishmania donovani as a suitable vaccine candidate. In silico analysis of this region revealed clusters of major histocompatibility complex class I and II binding epitopes in its motor domain region. A recombinant protein was expressed from this region and named rLvacc. The antigenicity and immunogenicity studies of this protein by Western blot analysis revealed that rLvacc is strongly recognized by sera from acute VL patients. To evaluate its immunogenicity, peripheral blood mononuclear cells from cured VL patients were separated, and a lymphocyte proliferation assay was carried out in the presence of rLvacc. After lymphocyte proliferation, the pooled culture supernatant was assayed for anti-rLvacc antibody titers using an enzyme-linked immunosorbent assay. The results showed that immunoglobulin G2 (IgG2) subtype antibodies were predominant, while IgG1 subtype antibodies were produced in very low titers. On the basis of these ex vivo preliminary findings, its immunogenicity was studied in BALB/c mice. Vaccination with the DNA construct generated a good cellular immune response with significant increases in gamma interferon and interleukin-2 (IL-2) cytokine levels (Th1), but no increase in IL-4 levels (Th2). Taken together, our findings suggest the kinesin motor domain region of L. donovani as a potential vaccine candidate against visceral leishmaniasis.