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Case Reports in Surgery and Invasive Procedures | Volume 3
March 11-12, 2019 | London, UK
Biomarkers
Plastic and Cosmetic Surgery
International Conference on
International Conference on
Joint Event
&
In vitro
evaluation of the new radiotracer
99m
Tc-HYNIC-PSMA for prostate cancer diagnosis
Monika Orzelowska, Michał Maurin
and
Piotr Garnuszek
National Centre for Nuclear Research Radioisotope Centre POLATOM, Poland
Introduction:
Prostate cancer is the second commonly occurring
malignance in men. The selection of an effective therapy form
depends on the proper assessment of the disease progression.
The prostate-specific membrane antigen (PSMA) is becoming
increasingly recognizedas a viable target for imaging and therapy
of prostate and other types of cancer.
As it is important to fully characterize the properties of
radiolabelled compounds before in vivo studies, the aim
of this work was to evaluate the in vitro biological activity
of new developed PSMA inhibitor -
99m
Tc-HYNIC-PSMA-
potential tracer for SPECT diagnosis of prostate cancer.
Method:
Saturationbindingassaywasperformedtodetermine
specificity of binding, dissociation constant (Kd) and maximal
concentration of receptors on the cell surface (Bmax). HYNIC-
PSMA inhibitor was labelled with
99m
Tc. The binding of
99m
Tc-
HYNIC-PSMA was evaluated by carrying out the studies using
the cellmembranes isolated fromLNCaP cells. Thenon-specific
binding was determined using membranes isolated from PC3
cells known not to express PSMA. IC50 values of the tested
compounds were determined by competitive binding assay
on LNCaP cell membranes using 131I-MIP1095 radioligand
with known high affinity to PSMA (IC50=0.3). As a reference
substance, PSMA11 was used.
Results:
99m
Tc-PSMA-T4 showed high specific affinity to
PSMA, which represented 99% of total binding. The Kd value
determined from the specific binding of the tested radioligand
was 5.47 nMand the Bmax was 9533 pmol/mg. The IC50 value
of HYNIC-PSMA was assessed at the level of 79.5 and it was 10
times lower than value obtained for PSMA11.
Conclusion:
High specific binding of
99m
Tc-HYNIC-PSMA to
the PSMA suggests its huge potential for prostate cancer
diagnosis. Comparison of the affinities of
99m
Tc-HYNIC-PSMA
and 68Ga-PSMA11 points out that despite SPECT technique
has a lower spatial resolution than PET,
99m
Tc-HYNIC-PSMA
can be a useful alternative in diagnosis and staging of prostate
cancer.
Speaker Biography
Monika Orzełowska graduated in Biotechnology from the Faculty of Biology and
Biotechnology in Maria-Curie Sklodowska University in Lublin, Poland. She obtained a
master’s degree in 2014. In August 2015, she started work in R&D Department at National
Centre for Nuclear Research, Radioisotope Centre POLATOM.
e:
Monika.Orzelowska@polatom.pl