Thymidylate synthase dimer disrupters induce DNA damage, halt cell growth, overcome drug resistance in colorectal cancer
Project BACKGROUND
Thymidylate synthase (TS) is an important target for cancer chemotherapy. Cells selected for high TS protein activity have low sensitivity to TS-targeting chemotherapeutic agents (5-FU and pemetrexed) and show cross-resistance to other chemotherapeutics (e.g., oxalilplatin). This causes failure of therapy in 30% of patients. To prevent/delay treatment-induced resistance, novel therapeutic strategies are required. In response to this need, we propose a new paradigm in TS inhibition consisting in small molecules, such as E7, that target the enzyme dimer interface and favor dissociation of the catalytically active dimer to the inactive monomers (Ddis). The Ddis are active in vivo against pancreatic cancer models.
HYPOTHESIS
1. Computational design and consequent E7 structural modification allow newly synthesized Ddis with improved molecular properties and better in vivo pharmacokinetics and anticancer activity.
2. By targeting hTS and favoring its proteasomal degradation, the Ddis halt DNA synthesis, cause DNA damage and trigger apoptosis, with resulting cancer cell growth inhibition.
3. Combinations of the Ddis with DNA damage targeting agents can counter drug resistance.
AIMS
1. to disclose the structural and mechanistic features of the Ddis:TS interaction.
2. to improve their potency and molecular properties, for a more favorable in vivo pharmacokinetics.
3. to clarify the link between the TS dimer disruption and its proteasomal degradation on one hand and DNA damage response on the other.
4. to show the capability of Ddis to halt drug-resistance development when given in combination with DNA damage-targeting drugs.
4. to achieve information on the efficacy of the newly synthesized Ddis in in vivo CRC models.
EXPERIMENTAL DESIGN
WP1 is devoted to medicinal chemistry design and synthesis of new Ddis; WP2 to assess their effect on cancer cells, thus identifying their intracellular targets and off-targets, and on tumors from patients (after 5FU treatment). WP3 will investigate the effects of the Ddis on DNA damage, apoptosis, TS protein stability and the like. WP4 will focus on combinations of Ddis with other anticancer drugs, aiming at decreasing drug resistance
emergence WP5 will focus on the pharmacokinetics and effectiveness of Ddis in CRC PDX animal models.
EXPECTED RESULTS
1. identification of at least 2 Ddis with suitable profiles to be progress towards advanced in vivo pre-clinical studies.
2. identification of two new Ddis active against a validated target such as TS and, by definitely reducing its cellular levels, able to halt drug resistance development.
IMPACT ON CANCER
•Disclosure of a new class of Ddis that, by dissociating the enzyme dimer, reduce its intracellular levels and lead to apoptosis by inducing a DNA damage response;
•proposal of synergistically-acting combinations of Ddis with drugs targeting the DNA damage, thus increasing their efficacy and reducing their doses.
•proving that these combinations can halt CRC drug resistance.
•providing new leads against CRC with promising biological properties to be developed further in a future project to counteract therapeutical drug resistance.
In perspective, this body of work should lead to savings in therapy costs, decrease of side effects and improvement of the patient's life quality, with faster recovery and return to active life and the corresponding general economic advantages.