Olaparib Synergizes the Anticancer Activity of Daunorubicin via Interaction with AKR1C3.
ABSTRACT: Olaparib is a potent poly (ADP-ribose) polymerase inhibitor currently used in targeted therapy for treating cancer cells with BRCA mutations. Here we investigate the possible interference of olaparib with daunorubicin (Daun) metabolism, mediated by carbonyl-reducing enzymes (CREs), which play a significant role in the resistance of cancer cells to anthracyclines. Incubation experiments with the most active recombinant CREs showed that olaparib is a potent inhibitor of the aldo-keto reductase 1C3 (AKR1C3) enzyme. Subsequent inhibitory assays in the AKR1C3-overexpressing cellular model transfected human colorectal carcinoma HCT116 cells, demonstrating that olaparib significantly inhibits AKR1C3 at the intracellular level. Consequently, molecular docking studies have supported these findings and identified the possible molecular background of the interaction. Drug combination experiments in HCT116, human liver carcinoma HepG2, and leukemic KG1? cell lines showed that this observed interaction can be exploited for the synergistic enhancement of Daun's antiproliferative effect. Finally, we showed that olaparib had no significant effect on the mRNA expression of AKR1C3 in HepG2 and KG1? cells. In conclusion, our data demonstrate that olaparib interferes with anthracycline metabolism, and suggest that this phenomenon might be utilized for combating anthracycline resistance.
Project description:Aldo-keto reductase 1C3 (AKR1C3) is a human enzyme that catalyzes the NADPH-dependent reduction of steroids and prostaglandins. AKR1C3 overexpression is associated with the proliferation of hormone-dependent cancers, most notably breast and prostate cancers. Nonsteroidal anti-inflammatory drugs (NSAIDs) and their analogues are well characterized inhibitors of AKR1C3. Here, the X-ray crystal structure of 3-phenoxybenzoic acid in complex with AKR1C3 is presented. This structure provides useful information for the future development of new anticancer agents by structure-guided drug design.
Project description:BACKGROUND:Human 17?-hydroxysteroid dehydrogenase type 5 (17?-HSD5) formally known as aldo-keto reductase 1C3 (AKR1C3) play a major role in the formation and metabolism of androgens. The enzyme is highly expressed in the prostate gland and previous studies indicate that genetic variation in the AKR1C3 gene may influence the prostate volume and risk of prostate cancer. AIM:Here we aimed to further study the genetic regulation of AKR1C3 and its putative role in prostate cancer. EXPERIMENTS:A previously identified promoter polymorphism (A>G, rs3763676) localized at -138 from the translational start site were studied in relation to prostate cancer in a Swedish population based case-control study including 176 patients diagnosed with prostate cancer and 161 controls. Moreover, we have studied the basal and androgen induced promoter activity of the AKR1C3 gene. Expression studies with AKR1C3 promoter reporter constructs were performed in HepG2 and DSL2 cells. RESULTS:We found that carriers of the promoter A-allele had a borderline significant decreased risk of prostate cancer (OR?=?0.59; 95% CI?=?0.32-1.08). We also show that dihydrotestosterone (DHT) induced the promoter activity of the A-allele 2.2-fold (p?=?0.048). Sp3 seem to play an important role in regulating the transcription activity of AKR1C3 and site-directed mutagenesis of a GC-box 78 base-pair upstream the ATG-site significantly inhibited the basal AKR1C3 promoter activity by 70%. CONCLUSION:These results further supports previous findings that the A>G promoter polymorphism may be functional and that AKR1C3 plays a critical role in prostate carcinogenesis. Our findings also show that the members of Sp family of transcription factors are important for the constitutive expression of AKR1C3 gene.
Project description:Aberrant androgen receptor (AR) activation is the major driver of castrate resistant prostate cancer (CRPC). CRPC is ultimately fatal and more therapeutic agents are needed to treat this disease. Compounds that target the androgen axis by inhibiting androgen biosynthesis and or AR signaling are potential candidates for use in CRPC treatment and are currently being pursued aggressively. Aldo-keto reductase 1C3 (AKR1C3) plays a pivotal role in androgen biosynthesis within the prostate. It catalyzes the 17-ketoreduction of weak androgen precursors to give testosterone and 5?-dihydrotestosterone. AKR1C3 expression and activity has been implicated in the development of CRPC, making it a rational target. Selective inhibition of AKR1C3 will be important, however, due to the presence of closely related isoforms, AKR1C1 and AKR1C2 that are also involved in androgen inactivation. We examine the evidence that supports the vital role of AKR1C3 in CRPC and recent developments in the discovery of potent and selective AKR1C3 inhibitors. This article is part of a Special Issue entitled 'CSR 2013'.
Project description:Aldo-Keto-Reductase 1C3 (type 5 17?-hydroxysteroid dehydrogenase (HSD)/prostaglandin (PG) F2? synthase) is the only 17?-HSD that is not a short-chain dehydrogenase/reductase. By acting as a 17-ketosteroid reductase, AKR1C3 produces potent androgens in peripheral tissues which activate the androgen receptor (AR) or act as substrates for aromatase. AKR1C3 is implicated in the production of androgens in castration-resistant prostate cancer (CRPC) and polycystic ovarian syndrome; and is implicated in the production of aromatase substrates in breast cancer. By acting as an 11-ketoprostaglandin reductase, AKR1C3 generates 11?-PGF2? to activate the FP receptor and deprives peroxisome proliferator activator receptor? of its putative PGJ2 ligands. These growth stimulatory signals implicate AKR1C3 in non-hormonal dependent malignancies e.g. acute myeloid leukemia (AML). AKR1C3 moonlights by acting as a co-activator of the AR and stabilizes ubiquitin ligases. AKR1C3 inhibitors have been used clinically for CRPC and AML and can be used to probe its pluripotency.
Project description:We report the design, synthesis, and evaluation of potent and selective inhibitors of aldo-keto reductase 1C3 (AKR1C3), an important enzyme in the regulatory pathway controlling proliferation, differentiation, and apoptosis in myeloid cells. Combination treatment with the nontoxic AKR1C3 inhibitors and etoposide or daunorubicin in acute myeloid leukemia cell lines, elicits a potent adjuvant effect, potentiating the cytotoxicity of etoposide by up to 6.25-fold and the cytotoxicity of daunorubicin by >10-fold. The results validate AKR1C3 inhibition as a common adjuvant target across multiple AML subtypes. These compounds in coadministration with chemotherapeutics in clinical use enhance therapeutic index and may avail chemotherapy as a treatment option to the pediatric and geriatric population currently unable to tolerate the side effects of cancer drug regimens.
Project description:The aldo-keto reductase 1C3 (AKR1C3) has been heavily implicated in the propagation of prostate malignancy. AKR1C3 protein is elevated within prostate cancer tissue, it contributes to the formation of androgens and downstream stimulation of the androgen receptor (AR). Elevated expression of AKR1C3 is also reported in acute myeloid leukemia but the target nuclear receptors have been identified as members of the peroxisome-proliferator activated receptor (PPARs) subfamily. Thus, AKR1C3 cancer biology is likely to be tissue dependent and hormonally linked to the availability of ligands for both the steroidogenic and non-steroidogenic nuclear receptors.In the current study we investigated the potential for AKR1C3 to regulate the availability of prostaglandin-derived ligands for PPARg mainly, prostaglandin J2 (PGJ2). Using prostate cancer cell lines with stably reduced AKR1C3 levels we examined the impact of AKR1C3 upon proliferation mediated by PPAR ligands.These studies revealed knockdown of AKR1C3 had no effect upon the sensitivity of androgen receptor independent prostate cancer cells towards PPAR ligands. However, the reduction of levels of AKR1C3 was accompanied by a significantly reduced mRNA expression of a range of HDACs, transcriptional co-regulators, and increased sensitivity towards SAHA, a clinically approved histone deacetylase inhibitor.These results suggest a hitherto unidentified link between AKR1C3 levels and the epigenetic status in prostate cancer cells. This raises an interesting possibility of a novel rational to target AKR1C3, the utilization of AKRIC3 selective inhibitors in combination with HDAC inhibition as part of novel epigenetic therapies in androgen deprivation therapy recurrent prostate cancer.
Project description:Aldo-keto reductase 1C3 (AKR1C3) also known as type 5 17?-hydroxysteroid dehydrogenase has been implicated as one of the key enzymes driving the elevated intratumoral androgen levels observed in castrate resistant prostate cancer (CRPC). AKR1C3 inhibition therefore presents a rational approach to managing CRPC. Inhibitors should be selective for AKR1C3 over other AKR1C enzymes involved in androgen metabolism. We have synthesized 2-, 3-, and 4-(phenylamino)benzoic acids and identified 3-(phenylamino)benzoic acids that have nanomolar affinity and exhibit over 200-fold selectivity for AKR1C3 versus other AKR1C isoforms. The AKR1C3 inhibitory potency of the 4'-substituted 3-(phenylamino)benzoic acids shows a linear correlation with both electronic effects of substituents and the pK(a) of the carboxylic acid and secondary amine groups, which are interdependent. These compounds may be useful in treatment and/or prevention of CRPC as well as understanding the role of AKR1C3 in endocrinology.
Project description:Signet ring cell gastric carcinoma (SRCGC) is a lethal malignancy that has developed drug resistance to cisplatin therapies. The aim of this study was to characterize the acquisition of the cisplatin-resistance SRCGC cell line (KATO/DDP cells) and to understand the molecular mechanisms underlying cisplatin resistance. Transcriptomic and bioinformatic analyses were used to identify the candidate gene. This was confirmed by qPCR and Western blot. Aldoketoreductase1C1 and 1C3 (AKR1C1 and AKR1C3) were the most promising molecules in KATO/DDP cells. A specific inhibitor of AKR1C1 (5PBSA) and AKR1C3 (ASP9521) was used to enhance cisplatin-induced KATO/DPP cell death. Although cisplatin alone induced KATO/DDP apoptosis, a combination treatment of cisplatin and the AKR1C inhibitors had no influence on percent cell apoptosis. In conjunction with the autophagy inhibitor, 3MA, attenuated the effects of 5PBSA or ASP9521 to enhance cisplatin-induced cell death. These results indicated that AKR1C1 and 1C3 regulated cisplatin-induced KATO/DDP cell death via autophagy. Moreover, cisplatin in combination with AKR1C inhibitors and N-acetyl cysteine increased KATO/DDP cells' viability when compared with a combination treatment of cisplatin and the inhibitors. Taken together, our results suggested that AKR1C1 and 1C3 play a crucial role in cisplatin resistance of SRCGC by regulating redox-dependent autophagy.
Project description:There is considerable interest in the development of an inhibitor of aldo-keto reductase (AKR) 1C3 (type 5 17?-hydroxysteroid dehydrogenase and prostaglandin F synthase) as a potential therapeutic for both hormone-dependent and hormone-independent cancers. AKR1C3 catalyzes the reduction of 4-androstene-3,17-dione to testosterone and estrone to 17?-estradiol in target tissues, which will promote the proliferation of hormone dependent prostate and breast cancers, respectively. AKR1C3 also catalyzes the reduction of prostaglandin (PG) H(2) to PGF(2?) and PGD(2) to 9?,11?-PGF(2), which will limit the formation of anti-proliferative prostaglandins, including 15-deoxy-?(12,14)-PGJ(2), and contribute to proliferative signaling. AKR1C3 is overexpressed in a wide variety of cancers, including breast and prostate cancer. An inhibitor of AKR1C3 should not inhibit the closely related isoforms AKR1C1 and AKR1C2, as they are involved in other key steroid hormone biotransformations in target tissues. Several structural leads have been explored as inhibitors of AKR1C3, including non-steroidal anti-inflammatory drugs, steroid hormone analogues, flavonoids, cyclopentanes, and benzodiazepines. Inspection of the available crystal structures of AKR1C3 with multiple ligands bound, along with the crystal structures of the other AKR1C isoforms, provides a structural basis for the rational design of isoform specific inhibitors of AKR1C3. We find that there are subpockets involved in ligand binding that are considerably different in AKR1C3 relative to the closely related AKR1C1 or AKR1C2 isoforms. These pockets can be used to further improve the binding affinity and selectivity of the currently available AKR1C3 inhibitors. Article from the special issue on Targeted Inhibitors.
Project description:Drugs used for the treatment of castration resistant prostate cancer (CRPC) include Abiraterone acetate (Zytiga®) and Enzalutamide (XTANDI®). However, these drugs provide clinical benefit in metastatic disease for only a brief period before drug resistance emerges. One mechanism of drug resistance involves the overexpression of type 5 17-?-hydroxysteroid dehydrogenase (aldo-keto reductase 1C3 or AKR1C3), a major enzyme responsible for the formation of intratumoral androgens that activate the androgen receptor (AR). 3-((4-Nitronaphthalen-1-yl)amino)benzoic acid 1 is a "first-in-class" AKR1C3 competitive inhibitor and AR antagonist. Compound 1 was compared in a battery of in vitro studies with structurally related N-naphthyl-aminobenzoates, and AKR1C3 targeted therapeutics e.g. GTx-560 and ASP9521, as well as with R-bicalutamide, enzalutamide and abiraterone acetate. Compound 1 was the only naphthyl derivative that was a selective AKR1C3 inhibitor and AR antagonist in direct competitive binding assays and in AR driven reporter gene assays. GTx-560 displayed weak activity as a direct AR antagonist but had high potency in the AR reporter gene assay consistent with its ability to inhibit the co-activator function of AKR1C3. By contrast ASP9521 did not act as either an AR antagonist or block AR reporter gene activity. Compound 1 was the only compound that showed comparable potency to inhibit AKR1C3 and act as a direct AR antagonist. Compound 1 blocked the formation of testosterone in LNCaP-AKR1C3 cells, and the expression of PSA driven by the AKR1C3 substrate (4-androstene-3,17-dione) and by an AR agonist, 5?-dihydrotestosterone consistent with its bifunctional role. Compound 1 blocked the nuclear translocation of the AR at similar concentrations to enzalutamide and caused disappearance of the AR from cell lysates. R-biaclutamide and enzalutamide inhibited AKR1C3 at concentrations 200x greater than compound 1, suggesting that its bifunctionality can be explained by a shared pharmacophore that can be optimized.