Antisense oligonucleotides (oligos) have
been evaluated for treating prostate cancer in both in vivo
and in vitro models. This study
evaluates the growth inhibition of in vitro propagating LNCaP cells
employing mono- and bi-specific oligos
directed against BCL-2 and employing RT-PCR, the
expression of five apoptosis regulatory
proteins (BCL-2, bax, caspase-3, clusterin, AKT-1), a tumor
associated transcription factor (MED-12)
and an immune blockade associated regulatory marker (PDL1)
were evaluated. LNCaP prostate tumor
cells were incubated in the presence of oligos specifically
directed against BCL-2 (entering the
cells through a form of nanodelivery) and compared to lipofectin
containing controls. Significant, but
comparable, growth inhibition was produced by both mono- and
bi-specific forms. Employing RT-PCR to
determine BCL-2 expression, we found that the greatest
amount of mRNA suppression approached
100% for each type of oligo: Mono-specific MR4 (directed
only against BCL-2), 100%, and
bispecifics MR24 and MR42, 86% and 100% respectively. The
objective of these experiments was to
determine a compensatory response by cells to (again) evade
apoptosis in the presence of BCL-2
suppression. Levels of mRNA encoding non-targeted bax,
caspase-3, clusterin and AKT-1 were
initially evaluated, while additional experiments sought to
identify additional mechanisms of tumor
adaptability and resistance. Suppression of the apoptosis
inhibitor (BCL-2) in LNCaP cells did not
alter either bax or clusterin expression. However, nontargeted
caspase-3 (an apoptosis promoter) was
suppressed and non-targeted AKT-1 (an apoptosis
inhibitor) was enhanced. This suggests
that tumor variants can resist apoptosis through the altered
expression of non-targeted regulators of
apoptosis. Additional experiments identified other
mechanisms of compensation involving
transcription and immune regulation suggesting further
studies are needed.
Author (s)
Details
Marvin Rubenstein
Independent
Researcher, 1070 Cobblestone Ct., Northbrook, IL 60062, USA.
View Book :- https://bp.bookpi.org/index.php/bpi/catalog/book/239
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