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Updated: Aug 19, 2026

Identification and Characterization of Metastatic Factors by Gene Transfer into the Novel RIP-Tag; RIP-tva Murine Model
09:03

Identification and Characterization of Metastatic Factors by Gene Transfer into the Novel RIP-Tag; RIP-tva Murine Model

Published on: October 16, 2017

A type-II DNA topoisomerase and a catenating protein from the transplantable VX2 carcinoma

G F Riou, M Gabillot, M Barrois

    European Journal of Biochemistry
    |February 1, 1985
    PubMed

    Insights

    Rabbit tumor cells exhibit significantly higher type II topoisomerase activity than liver cells, suggesting potential as a model for developing new cancer therapies targeting DNA intercalating drugs.

    Area of Science:

    • Biochemistry
    • Molecular Biology
    • Oncology

    Background:

    • Topoisomerases are crucial enzymes involved in DNA replication and transcription.
    • Type II topoisomerases are implicated as targets for DNA intercalating anticancer drugs.
    • A highly tumorigenic rabbit tumor model (VX2) was utilized for enzyme characterization.

    Purpose of the Study:

    • To purify and characterize type II topoisomerase from a VX2 rabbit tumor.
    • To compare the enzymatic activity of tumor-derived topoisomerase II with that from normal rabbit liver.
    • To identify potential regulatory factors influencing topoisomerase II activity in cancer cells.

    Main Methods:

    • Isolation and purification of type II topoisomerase from VX2 tumor and rabbit liver cells.
    • Assays for decatenating, relaxation, and unknotting activities.
    • Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) for molecular mass determination.
    • Immunological cross-reactivity testing using anti-H1 antiserum.

    Main Results:

    • VX2 tumor cells displayed 40-100 times higher decatenating activity compared to rabbit liver.
    • Type II topoisomerases from both tumor and liver consisted of ~160 kDa subunits.
    • A ~30 kDa protein, identified as similar to H1-2 histone, was found to enhance DNA catenation by topoisomerase II.

    Conclusions:

    • The VX2 rabbit tumor exhibits significantly elevated type II topoisomerase activity, making it a relevant model for cancer research.
    • The identified histone-like protein may play a role in regulating topoisomerase II function in tumorigenesis.
    • The VX2 topoisomerase II and tumor model are valuable tools for screening novel antitumoral drugs.

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