Attenuated Listeria monocytogenes as a cancer vaccine vector for the delivery of CD24, a biomarker for hepatic cancer stem cells

Cell Mol Immunol. 2014 Mar;11(2):184-96. doi: 10.1038/cmi.2013.64. Epub 2014 Feb 3.

Abstract

Attenuated Listeria monocytogenes (LM) is a promising candidate vector for the delivery of cancer vaccines. After phagocytosis by antigen-presenting cells, this bacterium stimulates the major histocompatibility complex (MHC)-I and MHC-II pathways and induces the proliferation of antigen-specific T lymphocytes. A new strategy involving genetic modification of the replication-deficient LM strain ΔdalΔdat (Lmdd) to express and secrete human CD24 protein has been developed. CD24 is a hepatic cancer stem cell biomarker that is closely associated with apoptosis, metastasis and recurrence of hepatocellular carcinoma (HCC). After intravenous administration in mice, Lmdd-CD24 was distributed primarily in the spleen and liver and did not cause severe organ injury. Lmdd-CD24 effectively increased the number of interferon (IFN)-γ-producing CD8(+) T cells and IFN-γ secretion. Lmdd-CD24 also enhanced the number of IL-4- and IL-10-producing T helper 2 cells. The efficacy of the Lmdd-CD24 vaccine was further investigated against Hepa1-6-CD24 tumors, which were inguinally inoculated into mice. Lmdd-CD24 significantly reduced the tumor size in mice and increased their survival. Notably, a reduction of T regulatory cell (Treg) numbers and an enhancement of specific CD8(+) T-cell activity were observed in the tumor-infiltrating lymphocytes (TILs). These results suggest a potential application of the Lmdd-CD24 vaccine against HCC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers, Tumor / metabolism*
  • CD24 Antigen / genetics
  • CD24 Antigen / metabolism*
  • CD8-Positive T-Lymphocytes / immunology*
  • Cancer Vaccines*
  • Carcinoma, Hepatocellular / immunology
  • Carcinoma, Hepatocellular / therapy*
  • Cell Line, Tumor
  • Cytokines / metabolism
  • DNA Replication / genetics
  • DNA, Bacterial / genetics
  • Humans
  • Listeria monocytogenes / genetics*
  • Liver Neoplasms / immunology
  • Liver Neoplasms / therapy*
  • Lymphocyte Activation
  • Mice
  • Mice, Inbred C57BL
  • Neoplasm Transplantation
  • Neoplastic Stem Cells / immunology
  • Neoplastic Stem Cells / metabolism*
  • Th2 Cells / immunology*
  • Tumor Burden
  • Vaccines, Attenuated / genetics

Substances

  • Biomarkers, Tumor
  • CD24 Antigen
  • Cancer Vaccines
  • Cytokines
  • DNA, Bacterial
  • Vaccines, Attenuated