A specific pharmacophore model of sodium-dependent glucose co-transporter 2 (SGLT2) inhibitors

Sodium-dependent glucose co-transporter 2 (SGLT2) plays a pivotal role in maintaining glucose equilibrium in the human body, emerging as one of the most promising targets for the treatment of diabetes mellitus type 2. Pharmacophore models of SGLT2 inhibitors have been generated with a training set of 25 SGLT2 inhibitors using Discovery Studio V2.1. The best hypothesis (Hypo1(SGLT2)) contains one hydrogen bond donor, five excluded volumes, one ring aromatic and three hydrophobic features, and has a correlation coefficient of 0.955, cost difference of 68.76, RMSD of 0.85. This model was validated by test set, Fischer randomization test and decoy set methods. The specificity of Hypo1(SGLT2) was evaluated. The pharmacophore features of Hypo1(SGLT2) were different from the best pharmacophore model (Hypo1(SGLT1)) of SGLT1 inhibitors we developed. Moreover, Hypo1(SGLT2) could effectively distinguish selective inhibitors of SGLT2 from those of SGLT1. These results indicate that a highly predictive and specific pharmacophore model of SGLT2 inhibitors has been successfully obtained. Then Hypo1(SGLT2) was used as a 3D query to screen databases including NCI and Maybridge for identifying new inhibitors of SGLT2. The hit compounds were subsequently subjected to filtering by Lipinski's rule of five. And several compounds selected from the top ranked hits have been suggested for further experimental assay studies.     

SGLT2 inhibitor activates the STING/IRF3/IFN-β pathway and induces immune infiltration in osteosarcoma

SGLT2 (sodium-glucose cotransporter 2) is an important mediator of epithelial glucose transport and has been reported that SGLT2, robustly and diffusely expressed in malignant cancer cells, was overexpressed in various tumors, and inhibiting the SGLT2 expression significantly inhibited tumor progression. By blocking the functional activity of SGLT2, SGLT2 inhibitors have shown anticancer effects in several malignant cancers, including breast cancer, cervical cancer, hepatocellular cancer, prostate cancer, and lung cancer. However, the anticancer effect of SGLT2 inhibitors in osteosarcoma and the specific mechanism are still unclear. In the present study, we found that SGLT2 was overexpressed at the protein level in osteosarcoma. Furthermore, our results showed that the SGLT2 inhibitor significantly inhibited osteosarcoma tumor growth and induced infiltration of immune cells in vivo by upregulating STING expression and activating the IRF3/IFN-β pathway, which could attribute to the suppression of AKT phosphorylation. In addition, the combined treatment with SGLT2 inhibitor and STING agonist 2’3’-cGAMP exerted synergistic antitumor effects in osteosarcoma. Furthermore, the overexpression of SGLT2 at the protein level was correlated with the degradation of SGLT2 induced by TRIM21. This result demonstrated that SGLT2 is a novel therapeutic target of osteosarcoma, and that the SGLT2 inhibitor, especially in combination with 2’3’-cGAMP, is a potential therapeutic drug.Subject terms: Bone cancer, Cell signalling     

More than apical: Distribution of SGLT1 in Caco-2 cells

We investigated the distribution of the endogenous sodium-D-glucose cotransporter (SGLT1) in polarized Caco-2 cells, a model for enterocytes. A cellular organelle fraction was separated by free-flow electrophoresis and subjected to the analysis of endogenous and exogenous marker enzymes for various membrane vesicle components. Furthermore, the presence of SGLT1 was tested by an ELISA assay employing newly developed epitope specific antibodies. Thereby it was found that the major amount of SGLT1 resided in intracellular compartments and only a minor amount in apical plasma membranes. The distribution ratio between intracellular SGLT1 and apical membrane-associated SGLT1 was 2:1. Further immunocytochemical investigation of SGLT1 distribution in fixed Caco-2 cells by epifluorescence and confocal microscopy revealed that the intracellular compartments containing SGLT1 were associated with microtubules. Elimination of SGLT1 synthesis by incubation of cells with cycloheximide did not significantly reduce the size of the intracellular SGLT1 pool. Furthermore, the half-life of SGLT1 in Caco-2 cells was determined to be 2.5 days by metabolic labeling followed by immunoprecipitation. Our data suggest that most of the intracellular SGLT1 are not transporters en route from biosynthesis to their cellular destination but represent an intracellular reserve pool. We therefore propose that intracellular compartments containing SGLT1 are involved in the regulation of SGLT1 abundance at the apical cell surface. endosome; microtubules; enterocyte; D-glucose transport; antibodies     

Sodium-Glucose Transporter-2 (SGLT2; SLC5A2) Enhances Cellular Uptake of Aminoglycosides

Aminoglycoside antibiotics, like gentamicin, continue to be clinically essential worldwide to treat life-threatening bacterial infections. Yet, the ototoxic and nephrotoxic side-effects of these drugs remain serious complications. A major site of gentamicin uptake and toxicity resides within kidney proximal tubules that also heavily express electrogenic sodium-glucose transporter-2 (SGLT2; SLC5A2) in vivo. We hypothesized that SGLT2 traffics gentamicin, and promotes cellular toxicity. We confirmed in vitro expression of SGLT2 in proximal tubule-derived KPT2 cells, and absence in distal tubule-derived KDT3 cells. D-glucose competitively decreased the uptake of 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG), a fluorescent analog of glucose, and fluorescently-tagged gentamicin (GTTR) by KPT2 cells. Phlorizin, an SGLT2 antagonist, strongly inhibited uptake of 2-NBDG and GTTR by KPT2 cells in a dose- and time-dependent manner. GTTR uptake was elevated in KDT3 cells transfected with SGLT2 (compared to controls); and this enhanced uptake was attenuated by phlorizin. Knock-down of SGLT2 expression by siRNA reduced gentamicin-induced cytotoxicity. In vivo, SGLT2 was robustly expressed in kidney proximal tubule cells of heterozygous, but not null, mice. Phlorizin decreased GTTR uptake by kidney proximal tubule cells in Sglt2^+/− mice, but not in Sglt2^−/− mice. However, serum GTTR levels were elevated in Sglt2^−/− mice compared to Sglt2^+/− mice, and in phlorizin-treated Sglt2^+/− mice compared to vehicle-treated Sglt2^+/− mice. Loss of SGLT2 function by antagonism or by gene deletion did not affect gentamicin cochlear loading or auditory function. Phlorizin did not protect wild-type mice from kanamycin-induced ototoxicity. We conclude that SGLT2 can traffic gentamicin and contribute to gentamicin-induced cytotoxicity.     

Glycosylated dihydrochalcones as potent and selective sodium glucose co-transporter 2 (SGLT2) inhibitors

A series of glucose conjugates was synthesized and tested for inhibition of SGLT1 and SGLT2. The core structure was derived from compound 1a. Modification of the benzofuran moiety and 4'-substituent of the phenyl ring in compound 1a improved selectivity at SGLT2. Select compounds were compared to 1a in metabolic stability and in vivo efficacy studies.     

Discovery of non-glucoside SGLT2 inhibitors

A series of benzothiazinone and benzooxazinone derivatives were discovered as SGLT2 inhibitors. The optimization led to the discovery of compounds 31 and 32, which exhibited similar potency and better SGLT1 selectivity compared to dapagliflozin. These compounds may provide novel promising scaffolds, which are different from phlorizin-based SGLT2 inhibitors.     

A selectivity study of sodium‐dependent glucose cotransporter 2/sodium‐dependent glucose cotransporter 1 inhibitors by molecular modeling

Sodium‐dependent glucose cotransporters (SGLTs) play an important role in glucose reabsorption in the kidney and have been identified as promising targets to treat diabetes. Because of the side effects like glucose and galactose malabsorption by targeting SGLT1, highly selective SGLT2 inhibitors are more promising in the treatment of diabetes. To understand the mechanism of selectivity, we conducted selectivity‐based three‐dimensional quantitative structure–activity relationship studies to highlight the structure requirements for highly selective SGLT2 inhibitors. The best comparative molecular field analysis and comparative molecular similarity indices analysis models showed the noncross‐validated coefficient (r²) of 0.967 and 0.943, respectively. The predicted correlation coefficients (r²_pred) of 0.974 and 0.938 validated the reliability and predictability of these models. Besides, homology models of SGLT2 and SGLT1 were also constructed to investigate the selective mechanism from structure‐based perspective. Molecular dynamics simulation and binding free energy calculation were performed on the systems of a potent and selective compound interacting with SGLT2 and SGLT1 to compare the different binding modes. The simulation results showed that the stretch of the methylthio group on Met241 had an essential effect on the different binding modes between SGLT1 and SGLT2, which was consistent with the three‐dimensional quantitative structure–activity relationship analysis. Hydrogen bond analysis and binding free energy calculation revealed that SGLT2 binding complex was more stable and favorable than SGLT1 complex, which was highly correlated with the experimental results. Our obtained results give useful information for the investigation of the inhibitors' selectivity between SGLT2 and SGLT1 and will help for further development of highly selective SGLT2 inhibitors. Copyright © 2015 John Wiley & Sons, Ltd.     

Potential Place of SGLT2 Inhibitors in Treatment Paradigms for type 2 Diabetes Mellitus

Objective: Following the first Food and Drug Administration (FDA) approval in 2013, sodium glucose cotransporter 2 (SGLT2) inhibitors have generated much interest among physicians treating patients with type 2 diabetes mellitus (T2DM). Here, the role in treatment with this drug class is considered in the context of T2DM treatment paradigms.Methods: The clinical trials for the SGLT2 inhibitors are examined with a focus on canagliflozin, dapagliflozin, and empagliflozin.Results: Evidence from clinical trials in patients with T2DM supports the use of SGLT2 inhibitors either as monotherapy or in addition to other glucose-lowering treatments as adjuncts to diet and exercise, and we have gained significant clinical experience in a relatively short time.Conclusion: The drugs appear to be useful in a variety of T2DM populations, contingent primarily on renal function. Most obviously, SGLT2 inhibitors appear to be well suited for patients with potential for hypoglycemia or weight gain. In clinical trials, patients treated with SGLT2 inhibitors have experienced moderate weight loss and a low risk of hypoglycemic events except when used in combination with an insulin secretagogue. In addition, SGLT2 inhibitors have been shown to reduce blood pressure, so they may be beneficial in patients with T2DM complicated by hypertension. SGLT2 inhibitors were incorporated into the 2015 American Diabetes Association (ADA)/European Association for the Study of Diabetes (EASD) position statement on the management of hyperglycemia and received an even more prominent position in the American Association of Clinical Endocrinologists (AACE)/American College of Endocrinology (ACE) comprehensive diabetes management guidelines and algorithm.Abbreviations: AE = adverse event A1C = glycated hemoglobin CI = confidence interval CKD = chronic kidney disease DKA = diabetic ketoacidosis DPP-4 = dipeptidyl peptidase 4 eGFR = estimated glomerular filtration rate FDA = Food and Drug Administration FPG = fasting plasma glucose GLP-1 = glucagon-like peptide 1 HDL-C = high-density lipoprotein cholesterol HR = hazard ratio LADA = late-onset autoimmune diabetes of adulthood LDL-C = low-density lipoprotein cholesterol MACE = major adverse cardiovascular events SGLT1 = sodium glucose cotransporter 1 SGLT2 = sodium glucose cotransporter 2 T1DM = type 1 diabetes mellitus T2DM = type 2 diabetes mellitus UACR = urine albumin to creatinine ratio     

Heteroaryl-O-glucosides as novel sodium glucose co-transporter 2 inhibitors. Part 1

A series of benzo-fused heteroaryl-O-glucosides was synthesized and evaluated in SGLT1 and 2 cell-based functional assays. Indole-O-glucoside 10a and benzimidazole-O-glucoside 18 exhibited potent in vitro SGLT2 inhibitory activity.     

The design and synthesis of novel SGLT2 inhibitors: C-glycosides with benzyltriazolopyridinone and phenylhydantoin as the aglycone moieties

The sodium glucose co-transporter 2 (SGLT2) has received considerable attention in recent years as a target for the treatment of type 2 diabetes mellitus. This report describes the design, synthesis and structure–activity relationship (SAR) of C-glycosides with benzyltriazolopyridinone and phenylhydantoin as the aglycone moieties as novel SGLT2 inhibitors. Compounds 5p and 33b demonstrated high potency in inhibiting SGLT2 and high selectivity against SGLT1. The in vitro ADMET properties of these compounds will also be discussed.     

Sodium–glucose cotransporter 2 inhibitors and inflammation in chronic kidney disease: Possible molecular pathways

Clinical trials with sodium–glucose cotransporter 2 (SGLT2) inhibitors (empagliflozin, dapagliflozin, and canagliflozin) have shown a decrease in the progression of chronic kidney disease (CKD). SGLT2 inhibitors represent a new category of oral antidiabetic agents that can also reduce systolic and diastolic blood pressure, as well as serum uric acid, and improve the glomerular filtration rate. Apart from affecting renal hemodynamics and glycotoxicity, evidence suggests that SGLT2 inhibitors may be renoprotective due to their effects on inflammation in renal tissues. Inflammatory responses play a prominent role in the pathophysiology of CKD as several structural and functional disorders of renal failure are strongly related to the overproduction of proinflammatory mediators. The present review discusses the anti-inflammatory properties of SGLT2 inhibitors. The different molecular pathways through which SGLT2 inhibitors may affect inflammation in the kidneys are also commented upon.     

N-Indolylglycosides bearing modifications at the glucose C6-position as sodium-dependent glucose co-transporter 2 inhibitors

Suppression of glucose reabsorption through the inhibition of sodium-dependent glucose co-transporter 2 (SGLT2) is a promising therapeutic approach for the treatment of type 2 diabetes. To investigate the effect of C6-substitution on inhibition of SGLT2 by N-indolylglucosides, a small library of 6-triazole, 6-amide, 6-urea, and 6-thiourea N-indolylglycosides were synthesized and tested. A detailed structure–activity relationship (SAR) study culminated in the identification of 6-amide derivatives 6a and 6o as potent SGLT2 inhibitors, which were further tested for inhibitory activity against SGLT1. The data obtained indicated that 6a and 6o are mildly to moderately selective for SGLT2 over SGLT1. Both compounds were also evaluated in a urinary glucose excretion test and pharmacokinetic study; 6a was found capable of inducing urinary glucose excretion in normal SD rats.     

Effects of sodium glucose cotransporter-2 inhibitors on serum uric acid in type 2 diabetes mellitus: A systematic review with an indirect comparison meta-analysis

To describe the effects of sodium-glucose co-transporter 2 (SGLT2) inhibitors on serum uric acid (SUA) in patients with type 2 diabetes mellitus (T2DM). PubMed, EMBASE, and CENTRAL were searched for randomized controlled trials of SGLT2 inhibitors in patients with T2DM up to Aug 10, 2017, without language or date restrictions. Thirty-one studies totaling 13,650 patients were included. SGLT2 inhibitors significantly decreased SUA levels compared with placebo, canagliflozin WMD –37.02?μmol/L, 95% CI [–38.41, –35.63], dapagliflozin WMD –38.05?μmol/L, 95% CI [–44.47, –31.62], empagliflozin WMD –42.07?μmol/L, 95% CI [–46.27, –37.86]. The drug class effect of SUA reduction suggesting SGLT2 inhibitors might be beneficial for diabetic patients with hyperuricemia.     

Discovery of Ipragliflozin (ASP1941): a novel C-glucoside with benzothiophene structure as a potent and selective sodium glucose co-transporter 2 (SGLT2) inhibitor for the treatment of type 2 diabetes mellitus

A series of C-glucosides with various heteroaromatics has been synthesized and its inhibitory activity toward SGLTs was evaluated. Upon screening several compounds, the benzothiophene derivative (14a) was found to have potent inhibitory activity against SGLT2 and good selectivity versus SGLT1. Through further optimization of 14a, a novel benzothiophene derivative (14h; ipragliflozin, ASP1941) was discovered as a highly potent and selective SGLT2 inhibitor that reduced blood glucose levels in a dose-dependent manner in diabetic models KK-A(y) mice and STZ rats.     

Synthesis and biological evaluation of 6-hydroxyl C-aryl glucoside derivatives as novel sodium glucose co-transporter 2 (SGLT2) inhibitors

The sodium glucose co-transporter 2 (SGLT2) was considered as an important target for the treatment of type 2 diabetes mellitus in recent years. This report describes the design and synthesis of a series of novel SGLT2 inhibitors (11a–17a) as well as their dehydrate dihydrofuran derivatives (11b–17b), which were prepared by Mitsunobu reaction. Their SGLT2 inhibitory activity was also evaluated, and 16a and 17a were found to be the most potent compounds with IC₅₀ values of 0.63 and 0.81?nM, respectively. However, all the dehydrate derivatives lose the SGLT2 inhibitory activity, with inhibition percentage no more than 66.5% at the concentration of 0.5?μM, which might because of the configuration inversion at C-2 of glucose. In conclusion, the present study improves understanding of the SAR of SGLT2 inhibitors, and provided more information that could be applied to design new molecules.     

Synthesis and biological evaluation of N-glucosyl indole derivatives as sodium-dependent glucose co-transporter 2 inhibitors

Sodium-dependent glucose co-transporter 2 (SGLT2) inhibition has been demonstrated to efficiently control hyperglycemia via an insulin secretion-independent pathway. The unique mode of action eliminates the risk of hypoglycemia and makes SGLT2 inhibitors an attractive option for the treatment of type 2 diabetes. In a continuation of our previous studies on SGLT2 inhibitors bearing different sugar moieties, sixteen new N-glucosyl indole derivatives were designed, synthesized, and evaluated for their inhibitory activity against hSGLT2. Of these sixteen, acethydrazide-containing N-glucosyl indole 9d was found to be the most potent SGLT2 inhibitor, and caused a significant elevation in urine glucose excretion in rats at 50 mg/kg, relative to the vehicle control.     

Design and synthesis of fluorescent SGLT2 inhibitors

The design and synthesis of the first fluorophore-conjugated SGLT2 inhibitors is described. The mode of linking the fluorophore to the SGLT2 pharmacophore was found to be crucial in achieving optimum potency. Superior potency to phlorizin was provided by examples containing TAMRA, BODIPY, Cy3B and NBD fluorophores.     

Synthesis of pyridazine and thiazole analogs as SGLT2 inhibitors

With anticipation of the improvement in biological aspects in our SGLT2 program, novel pyridazinyl and thiazolyl analogs were designed and efficiently synthesized. The installation of the pyridazine ring at the anomeric carbon of d-glucopyranose was carried out in a stereoselective fashion. On the other hand, a series of thiazolyl analogs was also synthesized through a coupling reaction between perbenzyl gluconolactone 9 and 2-lithiothiazole. Biological activities of the compounds thus prepared were evaluated by the in vitro SGLT2 inhibition assay. Considering assay results, the novel benzylpyridazinyl and benzylthiazolyl analogs, disclosed in this article, could be a quick reference to prospective SGLT2 inhibitors useful for pharmacotherapy.