Salicylic acid metabolites and derivatives inhibit CDK activity: Novel insights into aspirin's chemopreventive effects against colorectal cancer

Abstract

Aspirin's potential as a drug continues to be evaluated for the prevention of colorectal cancer (CRC). Although multiple targets for aspirin and its metabolite, salicylic acid, have been identified, no unifying mechanism has been proposed to clearly explain its chemopreventive effects. Our goal here was to investigate the ability of salicylic acid metabolites, known to be generated through cytochrome P450 (CYP450) enzymes, and its derivatives as cyclin dependent kinase (CDK) inhibitors to gain new insights into aspirin's chemopreventive actions. Using in vitro kinase assays, for the first time, we demonstrate that salicylic acid metabolites, 2,3-dihydroxy-benzoic acid (2,3-DHBA) and 2,5-dihydroxybenzoic acid (2,5-DHBA), as well as derivatives 2,4-dihydroxybenzoic acid (2,4-DHBA), 2,6-dihydroxybenzoic acid (2,6-DHBA), inhibited CDK1 enzyme activity. 2,3-DHBA and 2,6-DHBA did not inhibit CDK2 and 4; however, both inhibited CDK-6 activity. Interestingly, another derivative, 2,4,6-trihydroxybenzoic acid (2,4,6-THBA) was highly effective in inhibiting CDK1, 2, 4 and 6 activity. Molecular docking studies showed that these compounds potentially interact with CDK1. Immunoblotting experiments showed that aspirin acetylated CDK1, and pre-incubation with salicylic acid and its derivatives prevented aspirin-mediated CDK1 acetylation, which supported the data obtained from molecular docking studies. We suggest that intracellularly generated salicylic acid metabolites through CYP450 enzymes within the colonic epithelial cells, or the salicylic acid metabolites generated by gut microflora may significantly contribute to the preferential chemopreventive effect of aspirin against CRC through inhibition of CDKs. This novel hypothesis and mechanism of action in aspirin's chemopreventive effects opens a new area for future research. In addition, structural modification to salicylic acid derivatives may prove useful in the development of novel CDK inhibitors in cancer prevention and treatment.

Evidence That Calebin A, a Component of Curcuma Longa Suppresses NF-κB Mediated Proliferation, Invasion and Metastasis of Human Colorectal Cancer Induced by TNF-β (Lymphotoxin)

“…Furthermore, several reports have demonstrated that a residue Cyc38 of p65-NF-κB is essential for the specific binding/interaction to the DNA in different tumor cells [40,43,46,66]. Interestingly, recent studies suggested that polyphenols may mediate their anti-proliferative effects in colon cancer cells through targeting the cyclin-dependent kinase (CDK) activity [67,68]. As the NF-kB family is tightly involved in cell cycle regulation through actions on the CDK/cyclin-dependent kinase inhibitors (CKI) system [69], here, Calebin A, through inhibition of NF-kB DNA binding, may directly suppress cell cycle activation.…”

A review on gentisic acid as a plant derived phenolic acid and metabolite of aspirin: Comprehensive pharmacology, toxicology, and some pharmaceutical aspects

“…In another study, GA proposed to have chemopreventive effects in colorectal cancer (Dachineni et al, ). It is known that cyclin dependent kinases (CDKs) including CDK1, CDK2, CDK3, CDK4, CDK5, and CDK6 are key regulators of the cell cycle regulation, which activated through binding with cyclins, including cyclin A, B, C, and D. When CDK activated via binding to cyclins, facilitated the progression of cell cycle, for example, from G 2 to M phase.…”

“…So the inhibitors of CDK may prove to be useful in cancer prevention and treatment (Malumbres & Barbacid, ). In a study (Dachineni et al, ), the ability of SA metabolites in CDK inhibition was investigated. It was shown that GA interferes with Asp146 in CDK1 through –COOH group and Arg 135 in Cyclin B1 through –OH group and consciously inhibited it.…”

“…So the inhibitors of CDK may prove to be useful in cancer prevention and treatment (Malumbres & Barbacid, 2009). In a study (Dachineni et al, 2017), the ability of SA metabolites in CDK inhibition was investigated. It was shown that GA interferes with Asp146 in In a study by Altinoz, Elmaci, Cengiz, Emekli-Alturfan, and Ozpinar (2018), it was supposed that aspirin's prevention of breast and brain cancer might be associated with GA.…”

Compound C enhances the anticancer effect of aspirin in HER-2-positive breast cancer by regulating lipid metabolism in an AMPK-independent pathway

“…Moreover, aspirin may also indirectly activate AMPK through other processes [14]. It has been reported that aspirin and its metabolites regulate cyclin-dependent kinase (CDK) [15,16] and Wnt/β-catenin signaling [17,18].…”