School of Medical Sciences


Identification of human oxidoreductases that activate bioreductive prodrugs

Project Leader


Translational Therapeutics Main Page

 

All bioreductive prodrugs share a common mechanism of activation, undergoing reductive metabolism by cellular enzymes called oxidoreductases to form toxic species. The capacity for prodrugs to act as single-electron (1e) acceptors is opposed by molecular oxygen and consequently they function as direct oxygen sensors. However two-electron (2e) reduction can bypass this oxygen inhibition step. It is important to understand which enzymes are relevant and in what types of cancer they are found so that bioreductive prodrugs can be used in an optimal clinical context.

 

PR104A (and analogues)

We seek to identify the human enzymes responsible for the metabolic reduction (activation) of the prodrug PR-104A and its analogues. To date we have shown that several diflavin oxidoreductases (POR, MTRR, NDOR1, NOS2A) are involved in the hypoxic activation of PR-104A. In addition, we have shown that aldo-keto reductase 1C3 can activate PR-104A independent of a tissue oxygenation status. AKR1C3, is a ketosteroid reductase that has not previously been described as an aerobic (2e) nitroreductase. This oxygen-independent PR-104A activation raises the possibility that it contributes to dose limiting myelotoxicity. In collaboration with the ACSRC's Medicinal Chemistry group, we are currently developing next generation analogues of PR-104A which are non-substrates for reduction by AKR1C3.

PR-104-1C3
Prodrug PR-104A bound in the active site of aldo-keto reductase 1C3
AKR1C3_array
Lung cancer tissue microarray stained for aldo-keto reductase 1C3 (AKR1C3) expression

Keywords: Prodrug, Oxidoreductases, Cytochrome P450 oxidoreductase, Aldo-keto reductase 1C3

 

PR509 (and analogues)

The hypoxia-selective multikinase inhibitors (HSMKIs) carry a permanent positive charge when in their deactivated (prodrug) state. Cumulative experimental evidence indicates the positively charged HSMKI prodrugs are cell excluded. Following reduction (activation) the positive charge is lost and the MKI are free to diffuse into cancer cells and inhibit the target protein kinase receptor activity. We are currently evaluating whether plasma membrane (cell-surface) reductases are responsible for the reduction of these novel agents. A library of candidate plasma membrane oxidoreductases have been identified and cloned with the intention of elucidating their role in HSMKI metabolism.

Keywords: Hypoxia-selective multikinase inhibitors, Target protein kinase receptor

Collaborators: Medicinal Chemistry Group, Dr Gabi Dachs

 

Related publications


Guise,C.P., Abbattista,M.R., Tipparaju,S.R., Lambie,N.K., Su,J., Li,D., Wilson,W.R., Dachs,G.U., Patterson,A.V. Diflavin Oxidoreductases Activate the Bioreductive Prodrug PR-104A under Hypoxia. Molecular Pharmacology 2012; 81 (1): 31-40. (PMID: 21984255)

Guise,C.P., Abbattista,M.R., Singleton,R.S., Holford,S.D., Connolly,J., Dachs,G.U., Fox,S.B., Pollock,R., Harvey,J., Guilford,P., DoƱate,F., Wilson,W.R., Patterson,A.V. The bioreductive prodrug PR-104A is activated under aerobic conditions by human aldo-keto reductase 1C3. Cancer Research 2010; 70 (4): 1573-1584. (PMID:20145130)

Jameson, M.B., Rischin, D., Pegram, M., Gutheil, J., Patterson, A.V., Denny, W.A. and Wilson, W.R. A phase I pharmacokinetic trial of PR-104, a nitrogen mustard prodrug activated by both hypoxia and aldo-ketoreductase 1C3, in patients with solid tumors. Cancer Chemotherapy Pharmacology 2010; 65 (4): 791-801. (PMID:20012293). 

Gu, Y., Guise, C.P., Abbattista, M., Lie, J., Sun, X., Atwell, G.J., Boyd, M., Patterson, A.V., Wilson, W.R. Reductive metabolism of the dinitrobenzamide mustard anticancer prodrug PR-104 in mice. Chemotherapy Pharmacology 2011; 67 (3): 543-555. (PMID:20473609)

Gu, Y., Patterson, A.V., Atwell, G.J., Chernikova, S.B., Brown, J.M., Thompson, L.H. and Wilson, W.R. Roles of DNA repair and reductase activity in the cytotoxicity of the hypoxia-activated dinitrobenzamide mustard PR-104A. Molecular Cancer Therapeutics 2009, 8 (6): 1714-1723. (PMID:19509245)

Patterson, A.V., Ferry, D.M., Edmunds, S.J., Gu, Y., Singleton, R.S., Patel, K., Pullen, S.M., Syddall, S.P., Hicks, K.O. Atwell, G.J., Yang, S., Denny, W.A. and Wilson, W.R. Mechanism of action and preclinical antitumor activity of the novel hypoxia-activated DNA crosslinking agent PR-104. Clinical Cancer Research 2007; 13: 3922-3932. (PMID:17606726)

Guise C.P., Wang A.T.W., Theil A., Bridewell D.J., Wilson W.R. and Patterson A.V. Identification of human reductases that activate the dinitrobenzamide mustard prodrug PR-104A: a role for cytochrome P450 reductase under hypoxia. Biochemical Pharmacology 2007; 74: 810-820. (PMID:17645874)