Induction of CTLs by DCs pulsed with K-ras mutant peptide on the surface of nanoparticles in the treatment of pancreatic cancer
ABSTRACT The aim of this study was to investigate the role of specific cytotoxic T lymphocytes (CTLs) activated by dendritic cells (DCs) presenting cationic nanoparticles with the K-ras (12-Val) mutant peptide in the killing of different pancreatic cancer cell lines in vivo and in vitro. Peripheral blood DCs were induced by rhGM-CSF and IL-4 and cultured. DCs were sensitized by whole antigen of PANC-1 with expression of K-ras mutant, K-ras mutant peptide (K-ras+peptide) and cationic nanoparticles with K-ras mutant peptide (K-ras+peptide-CNP), respectively. Cell surface markers were measured by flow cytometry. Lymphocyte proliferation was detected by the 3H-TdR test, and IL-12 and IFN‑γ secretion was detected by ELISA. 125I-UdR was used to measure the killing effect of CTLs. The antitumor activity of CTLs in tumor-bearing nude mouse models prepared with PANC-1 and SW1990 cells was evaluated. Results showed that, compared with K-ras+peptide, low concentrations of K-ras+peptide-CNP were effectively presented by DCs (P<0.05). CTLs induced by DCs pulsed with whole tumor antigen had a significantly greater killing effect (P<0.05) on PANC-1 and SW1990 pancreatic cancer cells compared with K-ras+peptide- and K-ras+peptide-CNP-induced CTLs. CTLs induced by DCs pulsed with K-ras+peptide and K-ras+peptide- CNP had a specific killing effect (P<0.05) on PANC-1 cells and no effect (P>0.05) on SW1990 cells. In conclusion, cationic nanoparticles with the K-ras (12-Val) mutant peptide can be effectively presented by DCs at a low concentration. CTLs induced by K-ras+peptide-CNP had specific killing activity for the pancreatic cancer cell line with the K-ras mutant and significantly inhibited tumor growth and increased the survival time of tumor-bearing nude mice. Although this study confirmed that whole cell antigen induced a good antitumor immune response, the possibility of immune tolerance and autoimmunity which has been previously proven contribute to the difficulty in the application of this DC vaccine.
SourceAvailable from: Pradyumna Mishra[Show abstract] [Hide abstract]
ABSTRACT: Gastrointestinal (GI) malignancies are one of the most frequently occurring tumors found worldwide. Surgery remains the primary treatment for most solid tumors and adjuvant chemotherapy and radiotherapy are limited by lack of specificity and toxicity. In view of the poor survival rate, there is a great need to introduce new and effective therapeutic modalities. Recently, dendritic cells (DCs)-based vaccines are being explored as a promising therapeutic strategy but their success is limited by the tumor-induced immune escape mechanisms. This article provides a comprehensive analysis of clinical trials conducted using this approach. It also showcases the necessity of exploring nano-engineered strategies for improving the clinical utility of DC-vaccination for GI tract malignancies to overcome immune tolerance.Journal of Drug Targeting 10/2013; DOI:10.3109/1061186X.2012.731069 · 2.72 Impact Factor
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ABSTRACT: Mutant Kras (V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) is observed in more than 20% of non-small-cell lung cancers; however, no effective Kras target therapy is available at present. The Kras DNA vaccine may represent as a novel immunotherapeutic agent in lung cancer. In this study, we investigated the antitumor efficacy of the Kras DNA vaccine in a genetically engineered inducible mouse lung tumor model driven by Kras(G12D). Lung tumors were induced by doxycycline, and the therapeutic effects of Kras DNA vaccine were evaluated with delivery of Kras(G12D) plasmids. Mutant Kras(G12D) DNA vaccine significantly decreased the tumor nodules. A dominant-negative mutant Kras(G12D)N17, devoid of oncogenic activity, achieved similar therapeutic effects. The T-helper 1 immune response was enhanced in mice treated with Kras DNA vaccine. Splenocytes from mice receiving Kras DNA vaccine presented an antigen-specific response by treatment with peptides of Kras but not Hras or OVA. The number of tumor-infiltrating CD8(+) T cells increased after Kras vaccination. In contrast, Kras DNA vaccine was not effective in the lung tumor in transgenic mice, which was induced by mutant L858R epidermal growth factor receptor. Overall, these results indicate that Kras DNA vaccine produces an effective antitumor response in transgenic mice, and may be useful in treating lung cancer-carrying Ras mutation.Gene Therapy advance online publication, 31 July 2014 doi:10.1038/gt.2014.67.Gene Therapy 07/2014; DOI:10.1038/gt.2014.67 · 4.20 Impact Factor
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ABSTRACT: Aim: The work attempts to overcome tumor-associated immune tolerance using a surface-modified solid lipid nanoparticle (SLNP) delivery system for dendritic cell (DC) immunotherapy. Materials & methods: Different formulations of SLNPs (SLNPs-alone, cationic-SLNPs and mannosylated-SLNPs) were prepared using tumor cell lysates. Prepared nanoparticles were characterized and their ability to activate DCs to induce a tumor cell-specific response was assessed. Results: SLNPs induced a strong phagocytic signal to DCs without any significant toxicity. Comparatively, mannosylated-SLNPs evoked an optimum and effective cell-mediated immune response with no significant toxicity. Conclusion: Surface-modified SLNPs may play a pivotal role in designing a clinically translatable DC-based immunotherapy for gastrointestinal malignancies. This novel approach may also facilitate the treatment of residual disease, following standard therapy. Original submitted 9 February 2012; Revised submitted 19 August 2012.Nanomedicine 01/2013; DOI:10.2217/nnm.12.164 · 5.26 Impact Factor