Promotion of tumour metastases and induction of angiogenesis by native HIV-1 Tat protein from BK virus/tat transgenic mice

Alfredo Corallini, Diana Campioni, Cristina Rossi, Adriana Albini, Laura Possati, Marco Rusnati, Giancarlo Gazzanelli, Roberto Benelli, Luciana Masiello, Valentina Sparacciari, Marco Presta, Ferdinando Mannello, Gabriella Fontanini, Giuseppe Barbanti-Brodano

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: To characterize the T53 cell line and its clones derived from an adenocarcinoma of BK virus (BKV)/tat transgenic mice and to establish the role of native Tat in tumorigenicity, induction of metastases and angiogenesis. Design and methods: Tat was quantified by flow cytometry and chloramphenicol acetyltransferase (CAT) assays. Tumorigenicity and metastatic ability of cell lines were assayed in nude mice. Production of proteases was evaluated by a plasmin chromogenic assay and gelatinase zymography. The angiogenic effect was studied in vivo with conditioned medium from tumour cell lines. Results: Tat protein was detected in tumour cell lines in amounts from 600-7000 molecules/cell. Conditioned medium from tumour cell lines was able to transactivate an LTR-CAT in HL3T1 cells, indicating release of extracellular Tat. Tumour cell lines, inoculated into nude mice, induced angiogenic tumours with remarkable recruitment of host endothelial cells. Metastases were detected in lymph nodes, lungs, kidneys, and heart. Cell lines produced relevant amounts of proteases. Conditioned medium implanted in mice with matrigel induced an angiogenic response, enhanced by addition of heparin. Preincubation with an anti-Tat antibody abolished the angiogenic effect. Conclusions: Tat from cells from BKV/tat transgenic mice promotes tumorigenesis and formation of metastases and induces angiogenic activity. Angiogenesis occurs at physiological concentrations of Tat lower than 20 ng/ml. The effects of Tat on induction of metastases and angiogenesis appear to be mediated by activation of proteases.

Original languageEnglish
Pages (from-to)701-710
Number of pages10
JournalAIDS (London, England)
Volume10
Issue number7
Publication statusPublished - 1996

Keywords

  • Angiogenesis
  • HIV-1 Tat
  • Kaposi's sarcoma
  • Metastases
  • Proteolytic activity
  • Transgenic mice

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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