1 research outputs found
Targeting Prostate Cancer Using Bispecific T‑Cell Engagers against Prostate-Specific Membrane Antigen
Prostate cancer (PCa) tops the list of cancer-related
deaths in
men worldwide. Prostate-specific membrane antigen (PSMA) is currently
the most prominent PCa biomarker, as its expression levels are robustly
enhanced in advanced stages of PCa. As such, PSMA targeting is highly
efficient in PCa imaging as well as therapy. For the latter, PSMA-positive
tumors can be targeted directly by using small molecules or macromolecules
with cytotoxic payloads or indirectly by engaging the immune system
of the host. Here we describe the engineering, expression, purification,
and biological characterization of bispecific T-cell engagers (BiTEs)
that enable targeting PSMA-positive tumor cells by host T lymphocytes.
To this end, we designed the 5D3-αCD3 BiTE as a fusion of single-chain
fragments of PSMA-specific 5D3 and anti-CD3 antibodies. Detailed characterization
of BiTE was performed by a combination of size-exclusion chromatography,
differential scanning fluorimetry, and flow cytometry. Expressed in
insect cells, BiTE was purified in monodisperse form and retained
thermal stability of both functional parts and nanomolar affinity
to respective antigens. 5D3-αCD3’s efficiency and specificity
were further evaluated in vitro using PCa-derived
cell lines together with peripheral blood mononuclear cells isolated
from human blood. Our data revealed that T-cells engaged via 5D3-αCD3
can efficiently eliminate tumor cells already at an 8 pM BiTE concentration
in a highly specific manner. Overall, the data presented here demonstrate
that the 5D3-αCD3 BiTE is a candidate molecule of high potential
for further development of immunoÂtherapeutic modalities for
PCa treatment