Increased expression of HSP70 by colon cancer cells is not always associated with access to the dendritic cell cross-presentation pathway

MTBHsp70-exFPR1-pulsed Dendritic Cells Enhance the Immune Response against Cervical Cancer

Cervical cancer is the most common malignancy of the female reproductive system. Dendritic cell (DC)-based immunological therapy is a novel treatment for this cancer. DCs are specialized antigen-presenting cells (APCs) in the human immune system, and they can activate the T cells used in tumor immunological therapy. In this study, we developed a novel immunotherapeutic peptide by linking the Mycobacterium tuberculosis (MTB) heat shock protein 70 (Hsp70) functional peptide to the extracellular domain of FPR1, a protein overexpressed in cervical cancer, to obtain an MTBHsp70-exFPR1 fusion protein. Our experiments confirmed that the MTBHsp70-exFPR1 protein could promote DC maturation and induce the secretion of IL-12p70, IL-1β, and TNF-α. The antitumor effect of human cytotoxic T lymphocytes (CTLs) activated by autologous DCs was assessed in NOG mice. These results indicate that DCs pulsed with MTBHsp70-exFPR1 can enhance antitumor immunity against cervical cancer, providing a novel immune therapeutic strategy.

Apoptic Renal Carcinoma Cells are Better Inducers of Cross-Presenting Activity than Their Primary Necrotic Counterpart

Vaccination with tumor-loaded dendritic cells (DC) is a promising treatment strategy for patients with renal cell carcinoma (RCC). Cells undergoing cell death proved useful as a source of tumor antigen for DC loading. Both apoptotic and necrotic tumor cells have been shown to efficiently load RCC-tumor antigens on DC. However, no direct comparison of these two kinds of death has been attempted in the same RCC. We compared DC pulsed with apoptotic cells, whole cell lysates or their supernatants of the cell line K1, derived from a patient with clear cell RCC, to determine their ability to activate T cells. Monocyte-derived DCs were pulsed with the different sources of tumor antigen, matured and co-cultured with autologouos peripheral blood lymphocytes. After three weekly re-stimulations with DCs, generation of cytotoxic T lymphocytes CTL was assessed by IFN-γ release in an ELISpot assay in the presence of the sensitizing target. By comparison with lysate, apoptotic tumor cells induced a higher frequency of MHC class I-restricted IFN-γ releasing lymphocytes. A higher CTL response was induced by pulsing DCs with cell lysate supernatant compared with whole cell lysate. These results indicate that, although necrotic death has been regarded as highly permissive when compared to apoptotic death, the immunogenicity of the death treatment may vary from one tumor to another.