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In vivo electrogene transfer of interleukin‐12 inhibits tumor growth and lymph node and lung metastases in mouse mammary carcinomas
Author(s) -
Shibata MasaAki,
Ito Yuko,
Morimoto Junji,
Kusakabe Ken,
Yoshinaka Ryoji,
Otsuki Yoshinori
Publication year - 2006
Publication title -
the journal of gene medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.689
H-Index - 91
eISSN - 1521-2254
pISSN - 1099-498X
DOI - 10.1002/jgm.854
Subject(s) - pathology , lymphatic system , cd31 , angiogenesis , in vivo , metastasis , medicine , lymph node , microvessel , cancer research , lymph , cancer , biology , microbiology and biotechnology
Background Human breast cancer metastasizes mainly to lymph nodes, lungs, liver, and bone; in the majority of cases, it is the development of metastases which leads to death. In order to suppress mammary cancer metastasis, we applied in vivo electrogene transfer (non‐viral method) as a means of interleukin‐12 ( IL‐12 ) gene therapy on highly metastatic murine mammary cancer model. Methods Metastatic mammary tumors induced by inoculation in BALB/c female mice were treated by intratumoral injections of either a plasmid vector containing IL‐12 or empty vector and then subjected to in vivo electrogene transfer once a week for 8 weeks. Results Treatment with IL‐12 resulted in elevation of both IL‐12 and IFNγ levels in mammary tumors and in serum and intratumoral levels of CD4 and CD8 proteins were also increased. Tumor volumes and lymphatic and pulmonary metastases were significantly reduced. The histopathological changes induced by IL‐12 characteristically included marked inflammation, increased apoptosis, decreased DNA synthesis, peripheral influx of significantly greater numbers of active macrophages, and reduced blood microvessel density, and apoptotic vascular endothelial cells were frequently seen. Western blotting showed decreases in VEGFR‐3 of tumors exposed to IL‐12 gene therapy. In adjuvant immunofluorescence studies, the CD31‐positive endothelial cells of microvessels showed decreased VEGFR‐3 expression in IL‐12 ‐treated tumors. However, apparent alterations in VEGFR‐3 expression of podoplanin‐positive lymphatic endothelial cells were not observed in IL‐12 ‐treated tumors. Although recombinant IL‐12 did not inhibit tubular formation of human umbilical vein endothelial cells in a Matrigel assay, recombinant IFNγ did completely suppress the tubular formation. Conclusions In vivo electrogene transfer of IL‐12 exerts strong anti‐tumorigenic and anti‐metastatic effects likely due to T‐cell‐mediated immune responses as well as anti‐angiogenic action. Copyright © 2005 John Wiley & Sons, Ltd.