Abstract
Transforming growth factor β (TGF-β) is a powerful promoter of cancer progression and a key target for antitumor therapy. As cancer cells exhibit active cholesterol metabolism, high density lipoproteins (HDLs) appear as an attractive delivery system for anticancer TGFβ-inhibitory molecules. We constructed a plasmid encoding a potent TGF-β-blocking peptide (P144) linked to apolipoprotein A-I (ApoA-I) through a flexible linker (pApoLinkerP144). The ApoLinkerP144 sequence was then incorporated into a hepatotropic adeno-associated vector (AAVApoLinkerP144). The aim was to induce hepatocytes to produce HDLs containing a modified ApoA-I capable of blocking TGF-β. We observed that transduction of the murine liver with pApoLinkerP144 led to the appearance of a fraction of circulating HDL containing the fusion protein. These HDLs were able to attenuate TGF-β signaling in the liver and to enhance IL-12 -mediated IFN-γ production. Treatment of liver metastasis of MC38 colorectal cancer with AAVApoLinkerP144 resulted in a significant reduction of tumor growth and enhanced expression of IFN-γ and GM-CSF in cancerous tissue. ApoLinkerP144 also delayed MC38 liver metastasis in Rag2-/-IL2rγ-/- immunodeficient mice. This effect was associated with downregulation of TGF-β target genes essential for metastatic niche conditioning. Finally, in a subset of ret transgenic mice, a model of aggressive spontaneous metastatic melanoma, AAVApoLinkerP144 delayed tumor growth in association with increased CD8+ T cell numbers in regional lymph nodes. In conclusion, modification of HDLs to transport TGF-β-blocking molecules is a novel and promising approach to inhibit the growth of liver metastases by immunological and non-immunological mechanisms.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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CD3 Complex / metabolism
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Colorectal Neoplasms / drug therapy
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Colorectal Neoplasms / metabolism
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Colorectal Neoplasms / pathology*
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Female
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Genetic Vectors
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Granulocyte-Macrophage Colony-Stimulating Factor / metabolism
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Hepatocytes / metabolism
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Interferon-gamma / metabolism
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Lipoproteins, HDL / pharmacology*
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Liver / metabolism
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Liver Neoplasms / drug therapy
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Liver Neoplasms / metabolism*
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Liver Neoplasms / pathology*
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Mice
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Mice, Inbred BALB C
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Mice, Inbred C57BL
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Mice, Transgenic
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Molecular Targeted Therapy*
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Neoplasm Metastasis / prevention & control
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Plasmids / metabolism
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Proto-Oncogene Proteins c-akt / metabolism
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Proto-Oncogene Proteins c-ret / genetics
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Transforming Growth Factor beta1 / antagonists & inhibitors
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Transforming Growth Factor beta1 / metabolism*
Substances
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CD3 Complex
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Lipoproteins, HDL
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Tgfb1 protein, mouse
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Transforming Growth Factor beta1
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Interferon-gamma
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Granulocyte-Macrophage Colony-Stimulating Factor
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Proto-Oncogene Proteins c-ret
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Ret protein, mouse
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Akt1 protein, mouse
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Proto-Oncogene Proteins c-akt
Grants and funding
This work was supported by the agreement between FIMA and the “UTE project CIMA”, Red de Inmunoterapia IMMUNONET-SOE1/P1/E014, Instituto de Salud Carlos III, Fondo de Investigación Sanitaria (FIS PI10/00264), Fundación Mutua Madrileña, Dr. Mildred Scheel Foundation for Cancer Research (grant 108992, to V.U.) and by the Initiative and Networking Fund of the Helmholtz Association within the Helmholtz Alliance on Immunotherapy of Cancer (to V.U.). J.F. and J.M-E. were supported by a fellowship of Spanish Fondo de Investigación Sanitaria. N.D-V. was supported by a Martin Escudero fellowship. P.B. was supported by a Miguel Servet contract from Spanish Fondo de Investigación Sanitaria. J.D. was employee of Digna Biotech until June 2013. He has neither rights nor benefits from the data presented in this manuscript. This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.