The ability to regulate the cellular homeostasis of a higher organism through tight control of apoptosis and cell division is crucial for life. Dysregulation of these mechanisms is often associated with cancerous phenotypes in cells. Optimal
cancer therapy is a fine balance between effective
cancer cell killing and at the same time minimizing, or avoiding, damage to the surrounding healthy tissue. To obtain this, it is necessary to identify and inhibit molecular targets on which the
cancer cells are strongly dependent.
Survivin represents such a target, and it has been published previously that
peptide vaccines, the small-molecule
YM155, and the antisense molecule
LY2181308/ISIS23722, via different mechanisms, have been used as
survivin inhibitors. In this article, a new potent antisense inhibitor of
survivin,
SPC3042, is presented, and the properties of
SPC3042 are compared with the previously published antisense
drug,
LY2181308/ISIS23722.
SPC3042 is a 16-mer
locked nucleic acid (LNA)
oligonucleotide and designed as a fully phosphorothiolated gapmer containing 7 LNA
nucleotides in the flanks. The LNA
nucleotides in
SPC3042 provide nuclease stability and higher potency for
survivin mRNA inhibition compared with earlier generations of antisense
reagents. It is shown that the down-regulation of
survivin with
SPC3042 leads to cell cycle arrest, pronounced cellular apoptosis, and down-regulation of Bcl-2. It is also shown that
SPC3042 is a sensitizer of
prostate cancer cells to
Taxol treatment in vitro and in vivo.