Compounds and their uses

Abstract

This invention relates to compounds, pharmaceutical compositions, and methods of using the disclosed compounds for inhibiting PARP.

Description

[0001] This application claims benefit of U.S. Provisional Application No. 60 / 250,132, filed Dec. 1, 2000, and U.S. Provisinal Application No. 60 / 310,274, filed Aug. 9, 2001, the entire contents of each of which is incorporated herein by reference.[0002] The present invention relates to inhibitors of the nuclear enzyme poly(adenosine 5′-diphospho-ribose) polymerase [“poly(ADP-ribose) polymerase” or “PARP”, which is also referred to as ADPRT (NAD:protein (ADP-ribosyl transferase (polymersing)) and PARS (poly(ADP-ribose) synthetase) and provides compounds and compositions containing the disclosed compounds. Moreover, the present invention provides methods of using the disclosed PARP inhibitors to prevent and / or treat tissue damage resulting from cell damage or death due to necrosis or apoptosis; neural tissue damage resulting from, for example, ischemia and reperfusion injury, such as cerebral ischemic stroke, head trauma or spinal cord injury; neurological disorders and neurodegenera...

AI Technical Summary

Benefits of technology

These compounds effectively inhibit PARP activity, reducing tissue damage, extending cellular lifespan, and enhancing the sensitivity of tumor cells to radiation, thereby addressing the limitations of existing inhibitors while minimizing side effects.

Problems solved by technology

However, DNA damage causes an immediate activation of PARP by up to 500-fold.

Extensive PARP activation leads to severe depletion of NAD in cells suffering from massive DNA damage.

The short life of poly(ADP-ribose) (half-life<1 min) results in a rapid turnover rate.

Such a scenario is especially detrimental during ischaemia when deprivation of oxygen has already drastically compromised cellular energy output.

Subsequent free radical production during reperfusion is assumed to be a major cause of tissue damage.

During major cellular stresses the extensive activation of PARP can rapidly lead to cell damage or death through depletion of energy stores.

This excess release of glutamate in turn causes over-stimulation (excitotoxicity) of N-methyl-D-aspartate (NMDA), AMPA, Kainate and MGR receptors, which open ion channels and permit uncontrolled ion flow (e.g., Ca2+ and Na+ into the cells and K+ out of the cells) leading to overstimulation of the neurons.

The over-stimulated neurons secrete more glutamate, creating a feedback loop or domino effect which ultimately results in cell damage or death via the production of proteases, lipases and free radicals.

Attempts to prevent excitotoxicity by blocking NMDA, AMPA, Kainate and MGR receptors have proven difficult because each receptor has multiple sites to which glutamate may bind and hence finding an effective mix of antagonists or universal antagonist to prevent binding of glutamate to all of the receptor and allow testing of this theory, has been difficult.

Moreover, many of the compositions that are effective in blocking the receptors are also toxic to animals.

As such, there is presently no known effective treatment for glutamate abnormalities.

However, effective use of these PARP inhibitors, in the ways discussed above, has been limited by the concurrent production of unwanted side-effects (Milam et al., “Inhibitors of Poly(Adenosine Diphosphate-Ribose) Synthesis; Effect on Other Metabolic Processes”, Science, 223:589-91 (1984)).

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