@phdthesis{Hess2013,
  author    = {Heß, Michael},
  title     = {Vaccinia virus-encoded bacterial beta-glucuronidase as a diagnostic biomarker for oncolytic virotherapy},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86789},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2013},
  abstract  = {Oncolytic virotherapy represents a promising approach to revolutionize cancer therapy. Several preclinical and clinical trials display the safety of oncolytic viruses as wells as their efficiency against solid tumors. The development of complementary diagnosis and monitoring concepts as well as the optimization of anti-tumor activity are key points of current virotherapy research. Within the framework of this thesis, the diagnostic and therapeutic prospects of beta-glucuronidase expressed by the oncolytic vaccinia virus strain GLV-1h68 were evaluated. In this regard, a beta-glucuronidase-based, therapy-accompanying biomarker test was established which is currently under clinical validation. By using fluorescent substrates, the activity of virally expressed beta-glucuronidase could be detected and quantified. Thereby conclusions about the replication kinetics of oncolytic viruses in animal models and virus-induced cancer cell lysis could be drawn. These findings finally led to the elaboration and establishment of a versatile biomarker assay which allows statements regarding the replication of oncolytic viruses in mice based on serum samples. Besides the analysis of retrospective conditions, this test is able to serve as therapy-accompanying monitoring tool for virotherapy approaches with beta-glucuronidase-expressing viruses. The newly developed assay also served as complement to routinely used plaque assays as well as reference for virally expressed anti-angiogenic antibodies in additional preclinical studies. Further validation of this biomarker test is currently taking place in the context of clinical trials with GL-ONC1 (clinical grade GLV-1h68) and has already shown promising preliminary results. It was furthermore demonstrated that fluorogenic substrates in combination with beta-glucuronidase expressed by oncolytic viruses facilitated the optical detection of solid tumors in preclinical models. In addition to diagnostic purposes, virus-encoded enzymes could also be combined with prodrugs resulting in an improved therapeutic outcome of oncolytic virotherapy. In further studies, the visualization of virus-induced immune reactions as well as the establishment of innovative concepts to improve the therapeutic outcome of oncolytic virotherapy could be accomplished. In conclusion, the results of this thesis provide crucial findings about the influence of virally expressed beta-glucuronidase on various diagnostic concepts in the context of oncolytic virotherapy. In addition, innovative monitoring and therapeutic strategies could be established. Our preclinical findings have important clinical influence, particularly by the development of a therapy-associated biomarker assay which is currently used in different clinical trials.},
  subject      = {Vaccinia-Virus},
  language  = {en}
}