The Design, Structure-Activity, and kinetic studies of 3-Benzyl-5-oxa-1,2,3,4-Tetrahydro-2H-chromeno-(3,4-c)pyridin-8-yl sulfamates as Steroid sulfatase inhibitors.

Steroid sulfatase inhibitors block the local production of estrogenic steroids and are attractive agents for the treatment of estrogen-dependent cancers. Inspiration of coumarin-based inhibitors, we synthesized thirty-two 5-oxa-1,2,3,4-tetrahydro-2H-chromeno-(3,4-c)pyridin-8-yl sulfamates, focusing on the substitution derivatives on the adjacent phenyl ring and evaluated their abilities to block STS from human placenta and MCF-7 cells. SAR analysis revealed that the incorporation of chlorine at either meta and/or para position of the adjacent phenyl ring of the tricyclic skeleton enhanced STS inhibition. Di-substitutions at the adjacent phenyl ring were superior to mono and tri-substitutions. Further kinetic analysis of these compounds revealed that chloride-bearing compounds, such as 19m, 19v, and 19w, had KI of 0.02 to 0.11 nM and kinact/KI ratios of 8.8-17.5 nM-1min-1, a parameter indicated for the efficiency of irreversible inhibition. We also used the docking model to illustrate the difference in STS inhibitory potency of compounds. Finally, the safety and anti-cancer activity of selected compounds 19m, 19v, and 19w were also studied, showing the results of low cytotoxicity on NHDF cell line and being more potent than irosustat on ZR-75-1 cell, which was a hormone-dependent cancer cell line with high STS expression.

Targeting Colorectal Cancer with Conjugates of a Glucose Transporter Inhibitor and 5-Fluorouracil.

Overexpression of glucose transporters (GLUTs) in colorectal cancer cells is associated with 5-fluorouracil (1, 5-FU) resistance and poor clinical outcomes. We designed and synthesized a novel GLUT-targeting drug conjugate, triggered by glutathione in the tumor microenvironment, that releases 5-FU and GLUTs inhibitor (phlorizin (2) and phloretin (3)). Using an orthotopic colorectal cancer mice model, we showed that the conjugate exhibited better antitumor efficacy than 5-FU, with much lower exposure of 5-FU during treatment and without significant side effects. Our study establishes a GLUT-targeting theranostic incorporating a disulfide linker between the targeting module and cytotoxic payload as a potential antitumor therapy.

Design and synthesis of 3-benzylaminocoumarin-7-O-sulfamate derivatives as steroid sulfatase inhibitors.

Steroid sulfatase (STS) is a sulfatase enzyme that catalyzes the conversion of sulfated steroid precursors to free steroid. The inhibition of STS could abate estrogenic steroids that stimulate the proliferation and development of breast cancer, and therefore STS is a potential target for adjuvant endocrine therapy. In this study, a series of 3-benzylaminocoumarin-7-O-sulfamate derivatives targeting STS were designed and synthesized. Structure-relationship activities (SAR) analysis revealed that attachment of a benzylamino group at the 3-position of coumarin improved inhibitory activity. Compound 3j was found to have the highest inhibition activity against human placenta isolated STS (IC50  0.13 µM) and MCF-7 cell lines (IC50 1.35 µM). Kinetic studies found compound 3j to be an irreversible inhibitor of STS, with KI and kinact value of 86.9 nM and 158.7 min-1, respectively.

Sulfation pattern of chondroitin sulfate in human osteoarthritis cartilages reveals a lower level of chondroitin-4-sulfate.

Chondroitin sulfates (CS) account for more than 80% of the glycosaminoglycans of articular cartilage, which impart its physiological functions. We quantified the absolute concentration of the CS components of the full thickness cartilages from the knees of patients with terminal-phase osteoarthritis. Osteochondrol biopsies were removed from the medial femoral condyle and lateral femoral condyle of sixty female patients received total knee arthroplasty, aged from 58 to 83 years old. We found the total CS concentrations and chondroitin-4-sulfate disaccharide were significantly lowered in osteoarthritic samples. Microstructure analysis indicated while chondroitin-0-sulfate was equally distributed across different zones of the osteoarthritic cartilages, chondroitin-4-sulfate is significantly less in the deep zones. Down-regulation of sulfotransferases, the enzymes responsible for CS sulfation, in the lesion site of cartilage were observed. Our study suggested chondroitin-4-sulfate down-regulation can be a diagnostic marker for degraded osteoarthritis cartilage, with potential implications in cartilage regeneration.

S-Linked sialyloligosaccharides bearing liposomes and micelles as influenza virus inhibitors.

An efficient, homogeneous synthesis of phospholipid conjugation of S-Neu5Acα2-6Galß1-4GluNAcß1-3 (3) and its 6-sulphate analogue 4 has been developed. The self-assembled micelles and liposomes of these trisaccharides formed in solution were found to be inhibitors interfering with the entry of the H1N1 influenza virus into MDCK cells. Compound 3 bearing a liposome and a micelle displayed superior inhibitory activity than its 6-sulfate congener 4 in both the virus neutralization assay and the hemagglutination inhibition assay.

Synthesis and biological evaluation of novel C-aryl d-glucofuranosides as sodium-dependent glucose co-transporter 2 inhibitors.

Novel C-aryl-d-glucofuranosides were synthesized and evaluated for their capacity to inhibit human sodium-dependent glucose co-transporter 2 (hSGLT2) and hSGLT1. Compound 21q demonstrated the best in vitro inhibitory activity against SGLT2 in this series (EC50=0.62µM).

Development of a novel non-radioactive cell-based method for the screening of SGLT1 and SGLT2 inhibitors using 1-NBDG.

Sodium-coupled glucose co-transporters SGLT1 and SGLT2 play important roles in intestinal absorption and renal reabsorption of glucose, respectively. Blocking SGLT2 is a novel mechanism for lowering the blood glucose level by inhibiting renal glucose reabsorption and selective SGLT2 inhibitors are under development for treatment of type 2 diabetes. Furthermore, it has been reported that perturbation of SGLT1 is associated with cardiomyopathy and cancer. Therefore, both SGLT1 and SGLT2 are potential therapeutic targets. Here we report the development of a non-radioactive cell-based method for the screening of SGLT inhibitors using COS-7 cells transiently expressing human SGLT1 (hSGLT1), CHO-K1 cells stably expressing human SGLT2 (hSGLT2), and a novel fluorescent d-glucose analogue 1-NBDG as a substrate. Our data indicate that 1-NBDG can be a good replacement for the currently used isotope-labeled SGLT substrate, (14)C-AMG. The Michaelis constant of 1-NBDG transport (0.55 mM) is similar to that of d-glucose (0.51 mM) and AMG (0.40 mM) transport through hSGLT1. The IC50 values of a SGLT inhibitor phlorizin for hSGLT1 obtained using 1-NBDG and (14)C-AMG were identical (0.11 µM) in our cell-based system. The IC50 values of dapagliflozin, a well-known selective SGLT2 inhibitor, for hSGLT2 and hSGLT1 determined using 1-NBDG were 1.86 nM and 880 nM, respectively, which are comparable to the published results obtained using (14)C-AMG. Compared to (14)C-AMG, the use of 1-NBDG is cost-effective, convenient and potentially more sensitive. Taken together, a non-radioactive system using 1-NBDG has been validated as a rapid and reliable method for the screening of SGLT1 and SGLT2 inhibitors.