Luliberin analogues containing the nuclear localization sequence of the SV-40 virus T-antigen

Abstract

To improve the efficiency of anticancer drugs due to their delivery to intracellular targets a set of GnRH analogues containing nuclear localization signal (NLS) of SV-40 virus large T-antigen have been synthesized. NLS was attached to the parent molecule via ε-amino group of D-Lysine in position 1 or 6 of peptide sequence using orthogonal protection strategy. The biological activity studies revealed that incorporation of NLS moiety significantly increases cytotoxic activity of palmitoyl-containing GnRH analogues in vitro. The influence of tested peptides on tumor cells does not accompanied by the destruction of cell membrane, as confirmed in experiments with normal fibroblasts, used as a control.

Synthesis of GnRH analogues and their application in targeted gene delivery systems

“…Previously [11], conjugation of the NLS with GnRH at ε amino group of D lysin at position 6 was demonstrated not to interfere with the specific inter actions of the peptide carrier with GnRH receptors. Still, the possibility of DNA peptide complex forma tion and the mechanism of penetration through the tumor cell membrane was an open issue.…”

“…1) were described [11]. To study the effect of the structure of the ligand responsible for interactions with GnRH receptors on the efficiency of gene transfer to tumor cells, analogues VIII and IX, containing sequences of GnRH antagonist or agonist respectively, were synthe sized ( Fig.…”

“…Initially, peptide synthesis was performed by solid phase technique on a 4 methylbenzhydrylamine resin using the orthogonal protection strategy described in [11]. At peptide chain branching points, Fmoc-D Lys(BOC)-OH residue was introduced, then ε amino group was unblocked and synthesis of the NLS sequence was performed using the Boc/Bzl strategy.…”