Halogenated pyrrolopyrimidine analogues of adenosine from marine organisms: Pharmacological activities and potent inhibition of adenosine kinase

doi:10.1016/0006-2952(84)90225-9

Biochemical Pharmacology

Volume 33, Issue 3, 1 February 1984, Pages 347-355

https://doi.org/10.1016/0006-2952(84)90225-9 Get rights and content

Abstract

Two novel halogenated pyrrolopyrimidine analogues of adenosine, isolated from marine sources, have been examined for pharmacological and biochemical activities. 4-Amino-5-bromopyrrolo [2,3-d]pyrimidine, from a sponge of the genus Echinodictyum, had bronchodilator activity at least as potent as theophylline but with a different biochemical profile; unlike theophylline it had no antagonist activity at CNS adenosine receptors and it was quite a potent inhibitor of adenosine uptake and adenosine kinase in brain tissue. 5′:-Deoxy-5-iodotubercidin, isolated from the red alga Hypnea valentine, caused potent muscle relaxation and hypothermia when injected into mice. This compound was a very potent inhibitor of adenosine uptake into rat and guinea-pig brain slices and an extremely potent inhibitor of adenosine kinase from guinea-pig brain and rat brain and liver. Neither of these two pyrrolopyrimidine analogues was a substrate for, or an inhibitor of, adenosine deaminase. Neither compound appeared to have any direct agonist activity on guinea-pig brain adenosine-stimulated adenylate cyclase (A2 adenosine receptors). 5′:-Deoxy-5-iodotubercidin is unique in two respects: it appears to be the first naturally-occurring example of a 5′:-deoxyribosyl nucleoside and is the first example of a specifically iodinated nucleoside from natural sources. It may be the most potent adenosine kinase inhibitor yet described and, by virtue of its structure, may prove to be the most specific.

References (25)

J.A. Baird-Lambert et al.
Life Sci.
(1980)
L.P. Davies et al.
Neurochem. Res.
(1982)
L.P. Davies et al.
J. Neurochem.
(1979)
P.G.W. Plagemann et al.
Biochim. biophys. Acta
(1974)
C.G.A. Persson et al.
Life Sci.
(1982)
D.L. Powers et al.
J. pharm. Sci.
(1979)
Y.H. Kim et al.
J. nat. Prod.
(1981)
W. Bergmann et al.
J. org. Chem.
(1956)
R.J. Ouinn et al.
Tetrahedron Lett.
(1980)
J.T. Baker et al.J.T. Baker et al.

R. Kazlauskas et al.

Aust. J. Chem.

(1983)

D.D. Jamieson et al.

Clin. exp. Pharmac. Physiol

(1979)

Cited by (75)

Adenosine kinase: A key regulator of purinergic physiology
2021, Biochemical Pharmacology
Citation Excerpt :
This concept was originally based on the ability of AICA riboside (5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide, acadesine) to selectively enhance extracellular ADO levels in ischemic but not normal heart tissue [44]. Since adenosine kinase inhibition more effectively decreases cellular reuptake of ADO and thereby increases the local concentration of extracellular ADO in damaged as compared to normal tissues [43,45], adenosine kinase inhibition was also hypothesized to function as a site and event specific ADO modulator as well [39,46]. From a drug discovery perspective, the concept of adenosine kinase inhibition as a site and event specific therapeutic intervention was especially attractive given the reciprocal mechanism-based side effects associated with ADO receptor subtype agonists targeting either central nervous system or peripheral diseases [39].
Adenosine (ADO) is an essential biomolecule for life that provides critical regulation of energy utilization and homeostasis. Adenosine kinase (ADK) is an evolutionary ancient ribokinase derived from bacterial sugar kinases that is widely expressed in all forms of life, tissues and organ systems that tightly regulates intracellular and extracellular ADO concentrations. The facile ability of ADK to alter ADO availability provides a “site and event” specificity to the endogenous protective effects of ADO in situations of cellular stress. In addition to modulating the ability of ADO to activate its cognate receptors (P1 receptors), nuclear ADK isoform activity has been linked to epigenetic mechanisms based on transmethylation pathways. Previous drug discovery research has targeted ADK inhibition as a therapeutic approach to manage epilepsy, pain, and inflammation. These efforts generated multiple classes of highly potent and selective inhibitors. However, clinical development of early ADK inhibitors was stopped due to apparent mechanistic toxicity and the lack of suitable translational markers. New insights regarding the potential role of the nuclear ADK isoform (ADK-Long) in the epigenetic modulation of maladaptive DNA methylation offers the possibility of identifying novel ADK-isoform selective inhibitors and new interventional strategies that are independent of ADO receptor activation.
Biochemical and biological properties of 5-bromotubercidin: Differential effects on cellular DNA-directed and viral RNA-directed RNA synthesis
2008, Bioorganic and Medicinal Chemistry
We have studied the biochemical and biological properties of 5-bromotubercidin (4-amino-5-bromo-7-β-d-ribofuranosyl-pyrrolo [2,3-d]pyrimidine) (BrTu), a synthetic analogue of the highly cytotoxic pyrrolo[2,3-d]pyrimidine ribonucleoside antibiotic tubercidin (Tu) that interferes with numerous cellular processes, and has been shown to possess biological specificity and selectivity. Thus, BrTu entered the mammalian cell nucleotide pool by phosphorylation, was incorporated into RNA in an unmodified form and, as a consequence, reversibly inhibited (15 μM) mammalian cell growth and the synthesis of high-molecular-weight cellular RNA species (i.e., mRNA and rRNA). However, BrTu (300 μM) did not inhibit picornavirus RNA synthesis or multiplication, and thus discriminated between virus RNA-dependent and all forms of DNA-dependent RNA synthesis whether of cellular or viral origin; because of this BrTu should prove valuable as a metabolic probe for studying the cell–virus relationship. Furthermore, BrTu is a substrate for adenosine kinase (K_m = 24 μM), and is also its potent inhibitor (K_i = 0.93 μM); thus, low concentrations of BrTu (1.5 μM), which did not inhibit cell growth, blocked phosphorylation and the cellular uptake of other, highly cytotoxic pyrrolo-pyrimidine nucleoside analogues (e.g., tubercidin). This block in cellular uptake and incorporation of toxic analogues was associated with the protective effect of BrTu against cell killing by the analogues, providing a mechanism by which BrTu and these analogues can, as we reported elsewhere [J. Virol. 1999, 73, 6444], be used for the selective inactivation of replicating picornaviruses.
5-(3-Bromophenyl)-7-(6-morpholin-4-ylpyridin-3-yl)pyrido[2,3-d] pyrimidin-4-ylamine: Structure-activity relationships of 7-substituted heteroaryl analogs as non-nucleoside adenosine kinase inhibitors
2005, Bioorganic and Medicinal Chemistry
Citation Excerpt :
Inhibition of AK, as compared to inhibition of ADA, was shown to produce higher levels of endogenous ADO release from nervous tissue and enhanced anti-convulsant and anti-nociceptive effects in animal models.6 Previous strategies from our laboratories7 and others8–22 have focused on the identification of nucleoside-like inhibitors. Recently, high-throughput screening of Abbott proprietary compounds identified a pteridine lead structure, 1 (Chart 1).
4-Amino-5,7-disubstituted pyridopyrimidines are potent, non-nucleoside inhibitors of adenosine kinase (AK). We recently identified a potent, orally efficacious analog, 4 containing a 7-pyridylmorpholine substituted ring system as the key structural element of this template. In this report, we disclose the pharmacologic effects of five- and six-membered heterocyclic ring replacements for the pyridine ring in 4. These replacements were found to have interesting effects on in vivo efficacy and genotoxicity as well as in vitro potency. We discovered that the nitrogen in the heterocyclic ring at C(7) is important for the modulation of mutagenic side effects (Ames assay).
Inhibition of adenosine kinase attenuates interleukin-1- and lipopolysaccharide-induced alterations in articular cartilage metabolism
2005, Osteoarthritis and Cartilage
Citation Excerpt :
Alternative explanations should also be considered including the possibility that ITU was acting through another mechanism. ITU is a potent adenosine kinase inhibitor37–39, and it has frequently been used in experiments to increase extracellular adenosine levels6,40,41. The 1 μM concentration used in this study was selected based on the dose response of articular chondrocytes exposed to ITU in which maximal adenosine release was detected with 1 μM ITU without an adverse impact on cell viability6.
To investigate the effect of adenosine kinase inhibition on interleukin (IL)-1β- and lipopolysaccharide (LPS)-induced cartilage damage.
Articular cartilage was obtained from the metacarpophalangeal joints of 10 young adult horses. Following a stabilization period, weighed cartilage explants were exposed to IL-1β (10 ng/ml) or LPS (50 μg/ml) to induce cartilage degradation. To test the potential protective effects of adenosine, these explants were simultaneously exposed to adenosine (100 μM), the adenosine kinase inhibitor 5′iodotubercidin (ITU, 1 μM) or to both adenosine and ITU. After 72 h in culture, conditioned medium was collected for evaluation of glycosaminoglycan (GAG), nitric oxide (NO), prostaglandin E₂ (PGE₂) and matrix metalloproteinase (MMP)-3 release.
IL-1β and LPS stimulated significant release of GAG, NO, PGE₂ and MMP-3. Incubation with ITU significantly inhibited both IL-1β- and LPS-induced GAG release, but did not alter MMP-3 production. Exposure to ITU also reduced IL-1β-induced PGE₂ release and LPS-induced NO production. Direct adenosine supplementation did not attenuate the effects of IL-1β or LPS, and the addition of adenosine or ITU in the absence of IL-1β or LPS did not have any detectable effect on cartilage metabolism in this model.
The adenosine kinase inhibitor ITU attenuated experimentally induced cartilage damage in an in vitro cartilage explant model. Release of adenosine from chondrocytes may play a role in the cellular response to tissue damage in arthritic conditions and modulation of these pathways in the joint may have potential for treatment of arthropathies.
The adenosine kinase inhibitor ABT-702 augments EEG slow waves in rats
2004, Brain Research
Citation Excerpt :
Intracellular metabolism of ADO is under the control of the adenosine kinase (AK) that catalyzes the phosphorylation of ADO to AMP and is the rate-limiting enzyme regulating extracellular ADO concentrations [2]. Increased intracellular ADO by AK inhibition creates an unfavorable concentration gradient for the reuptake of ADO into the cell, thus increasing extracellular ADO [11,15,31]. Compounds that inhibit AK increase basal extracellular ADO levels both in vivo and in vitro [9,10,42].
ABT-702 is a novel and selective non-nucleoside adenosine kinase (AK) inhibitor that produces increases in endogenous extracellular adenosine. Adenosine (ADO) is thought to be an important neuromodulator of sleep, therefore, the effects of ABT-702 and AK inhibition were examined on rat EEG and sleep, and compared to ADO receptor agonists to further evaluate the role of ADO receptor activation on sleep related EEG patterns. ABT-702 (10.0–30.0 μmol/kg, i.p.) increased the amplitude of the 1–4 Hz band (Fast Fourier Transform (FFT) analysis, p<0.05), which is indicative of augmented sleep-related slow waves. Theophylline (5.0 μmol/kg, i.p.), a centrally active, non-selective adenosine receptor antagonist, attenuated the effects of ABT-702 (20.0 μmol/kg, i.p.) on EEG, whereas 8-(p-sulfophenyl)-theophylline (8-PST, 150.0 μmol/kg, i.p.), a peripherally active antagonist, did not, indicating that the EEG effects of ABT-702 are mediated by a central ADO receptor mechanism. The selective A₁ agonist N6-cyclopentyladenosine (CPA, 30.0 μmol/kg, i.p.) also increased the amplitude of 1–4 Hz band, but was not as efficacious as ABT-702. In contrast, the A_2A agonist CGS-21680 (1.0–10.0 μmol/kg, i.p.) and the non-selective agonist, N⁶-ethylcarboximidoadenosine (NECA, 0.03–0.1 μmol/kg, ip.), lowered 1–4 Hz amplitude for 2 h after injection. Finally, ABT-702 (10.0 μmol/kg, i.p.) was found to significantly increase slow wave sleep and decrease REM sleep in rats implanted with both EEG and EMG electrodes for evaluation of sleep. These studies demonstrate that increased extracellular adenosine through AK inhibition can elicit modulatory effects on EEG slow waves via an interaction with central ADO receptor subtypes.
Synthesis and biological evaluation of pteridine and pyrazolopyrimidine based adenosine kinase inhibitors
2004, Bioorganic and Medicinal Chemistry Letters
Three new approaches have been tested to modify existing pyridopyrimidine and alkynylpyrimidine classes of nonnucleoside adenosine kinase inhibitors 2 and 3. 4-Amino-substituted pteridines 8a–e were generally less active than corresponding 5- and 6-substituted pyridopyrimidines 2. Pyrazolopyrimidine 13c with IC₅₀=7.5 nM was superior to its open chain alkynylpyrimidine analog 13g (IC₅₀=22 nM) while pyrrolopyrimidines such as 17a were inactive.

View all citing articles on Scopus

^¶: The Institute closed in June 1981.

^†: Present address: Department of Behavioural Biology, Research School of Biological Sciences, Australian National University, Canberra, A.C.T. 2600, Australia.

^§: Present address: Department of Paediatrics, Westmead Centre, Westmead, N.S.W. 2145, Australia.

^∥: Present address: Department of Pharmacology, Sydney University, N.S.W. 2006, Australia.

View full text

Halogenated pyrrolopyrimidine analogues of adenosine from marine organisms: Pharmacological activities and potent inhibition of adenosine kinase

Abstract

Life Sci.

Neurochem. Res.

J. Neurochem.

Biochim. biophys. Acta

Life Sci.

J. pharm. Sci.

J. nat. Prod.

J. org. Chem.

Tetrahedron Lett.

Aust. J. Chem.

Clin. exp. Pharmac. Physiol