The present project is a logical pursuit of our BIOMED-1 programme (CT93-1500). During this programme we developed new anti-ras oligonucleotides. In the present programme we will carry out the necessary experiments to bring this new potential anti-cancer treatment to the clinic.
We have shown that antisense oligonucleotides directed to a point mutation in codon 12 of the Ha-ras mRNA selectively inhibited the proliferation of cells expressing the mutated Ha-ras gene. Tumour growth of these cells in nude mice was markedly inhibited after subcutaneous injection of antisense dodecamer absorbed to nanoparticles.
The predominant nuclease activity which degrades oligonucleotides intracellularly and extracellularly are 3'-exonucleases. By attaching short alkyl chains connected to the 3'-position of antisense dodecamer, we have enhanced stability of the dodecamer towards nucleases and lowered tumour growth inhibition dose by 100-fold.
The discovery of these highly active and selective oligonucleotide analogues prompts us to propose pharmaceutical and medical applications.
Activated mutated Ha-ras has been found in several cancers including bladder carcinomas. Oligonucleotides could be instilled intravesically, as an adjuvant therapy, in order to prevent progression or relapse after endoscopie resection. Therapeutic applications of antisense oligonucleotides to cancer treatment require information concerning the in vivo behaviour of olignonucleotides. Therefore, this proposal will focus on the in vivo evaluation of Ha-ras targeted 3'-end modified antisense oligonucleotides.
The proposal contains three main lines of investigation :
1. In vitro and in vivo evaluation of the efficacy of antisense oligonucleotides : Evaluation of original modifications which could improve the stability and the uptake of oligonucleotides.
2. Pharmacological studies : organ distribution, clearance kinetics and toxicity of modified dodeacamers will be studied in mammalians.
3. Collection of clinical samples and characterisation : the aim is to collect bladder carcinomas samples exhibiting ras mutation in order to establish primary culture and derived cell lines. At the same time antisense oligonucleotide activity will be evaluated and clinical trials will be started in the most optimal conditions.
Funding SchemeCSC - Cost-sharing contracts
2300 RA Leiden