| dc.description.abstract | Degree project, Programme in Medicine
To develop an in vitro method to measure the penetration of antibody-nuclide
conjugates in tumor tissue: initial attempts on ovarian cancer.
Diana Abona, January 2017
Supervisor: Prof Ragnar Hultborn
Department of Oncology. Institute of Clinical Sciences
Background. Ovarian cancer is the fifth leading cause of cancer death and the most
malignant of gynecological cancer. After standard treatment with surgery and
intravenous chemotherapy, 70% of all women will relapse. Therefore it is important
to develop new treatment methods for ovarian cancer.
Aim. The Targeted Alpha Therapy Group in Gothenburg develops a
radioimmunotherapy based on the use of an alpha particle emitting nuclide, 211-
Astatine, conjugated with ovarian cancer specific monoclonal antibodies, e.g. MX35.
Since the alpha particle track length is only 70 um it is essential to know how deep
into tumour cell clusters the antibody-nuclide complex can reach. Thus we wanted to
develop a simple in vitro method that enables measuring of how deep into an
experimental “micrometastasis”, the vector of the alphaemitting nuclide, i.e. the
antibody with various modifications with respect to size and affinity etc., can
penetrate.
Method. Hollow fibers with a diameter of 1 mm and permeable to molecules up to
500 kD are used. Cultured human ovarian cancer cells, Ovcar-3, in a dense
suspension is added into the "fiber" with a pipette. The fiber containng Ovcar-3 is
then centrifuged at approximately 3000 g for 15 minutes resulting in a densly
compacted cell cylinder, simulating a micrometastsis. The present work describes the
procedures used to reach this goal.
The use of this highly artificial micrometastasis model will be: The fiber with
compacted tumour cells is introduced into a solution containing the murine ovarian
cancer specific antibody (MX35). After different exposure times, the fiber with the
tumour cell cylinder is fixed in formalin. After usual dehydration, the fiber is
embedded in paraffin and cut in 5-10 μm sections. After rehydration,
immunohistochemistry is made using anti-mouse IgG antibody with fluorescence or
peroxidase analysis to see how deep the antibody penetrated into the compacted cell
cylinder.
Results. We succeded, after many attempts with different approaches, to produce a
relatively well filled fiber with tumour cells.
Conclusion. The work has involved several methodological developments with the
achievement of basic cell culture techniques and conventional histotechnology. We
have not yet fully reached the goal of reproducibly establishing a fully-filled fiber
with compacted cells. We will try with cells suspended in a medium of extracellular
matrix, as well as to try different degrees of centrifugation, fixation as well as
cryosection.
Key words: Ovarian cancer, Alpharadioimmunotherapy, Astatine-211 | sv |
