Qianqian Qiu

Free fatty acid receptor agonists for the treatment of type 2 diabetes: drugs in preclinical to phase II clinical development

ABSTRACT Introduction: The alarming prevalence of type 2 diabetes mellitus (T2DM) stimulated the exploitation of new antidiabetic drugs with extended durability and enhanced safety. In this regard, the free fatty acid receptor 1 (FFA1) and FFA4 have emerged as attractive targets in the last decade. FFA1 has prominent advantages in promoting insulin and incretin secretion while FFA4 shows great potential in incretin secretion, insulin sensitization and anti-inflammatory effects. Area covered: Herein, the authors focus specifically on FFA1 and FFA4 agonists in clinical trials and preclinical development. LY2922470, P11187 and SHR0534 are currently active in clinical trials while the CNX-011-67, SAR1, DS-1558 and BMS-986118 are in preclinical phase. The information for this review is retrieved from Integrity, Scifinder, Espacenet and clinicaltrials.gov databases. Expert opinion: Current proof-of-concept in clinical trials suggests that FFA1 agonists have a significant improvement for T2DM without the risk of hypoglycemia. However, there are still several challenging problems including the mechanism of the receptor and the efficacy and safety of the ligands.

Design, synthesis and Structure-activity relationship studies of new thiazole-based free fatty acid receptor 1 agonists for the treatment of type 2 diabetes.

The free fatty acid receptor 1 (FFA1/GPR40) has attracted interest as a novel target for the treatment of type 2 diabetes. Several series of FFA1 agonists including TAK-875, the most advanced compound terminated in phase III studies due to concerns about liver toxicity, have been hampered by relatively high molecular weight and lipophilicity. Aiming to develop potent FFA1 agonists with low risk of liver toxicity by decreasing the lipophilicity, the middle phenyl of TAK-875 was replaced by 11 polar five-membered heteroaromatics. Subsequently, systematic exploration of SAR and application of molecular modeling, leads to the identification of compound 44, which was an excellent FFA1 agonist with robustly hypoglycemic effect both in normal and type 2 diabetic mice, low risks of hypoglycemia and liver toxicity even at the twice molar dose of TAK-875. Meanwhile, two important findings were noted. First, the methyl group in our thiazole series occupied a small hydrophobic subpocket which had no interactions with TAK-875. Furthermore, the agonistic activity revealed a good correlation with the dihedral angle between thiazole core and the terminal benzene ring. These results promote the understanding of ligand-binding pocket and might help to design more promising FFA1 agonists.

Synthesis and biological evaluation of phenoxyacetic acid derivatives as novel free fatty acid receptor 1 agonists

Free fatty acid receptor 1 (FFA1) is a new potential drug target for the treatment of type 2 diabetes because of its role in amplifying glucose-stimulated insulin secretion in pancreatic β-cell. In the present studies, we identified phenoxyacetic acid derivative (18b) as a potent FFA1 agonist (EC50=62.3 nM) based on the structure of phenylpropanoic acid derivative 4p. Moreover, compound 18b could significantly improve oral glucose tolerance in ICR mice and dose-dependently reduced glucose levels in type 2 diabetic C57BL/6 mice without observation of hypoglycemic side effect. Additionally, compound 18b exhibited acceptable PK profiles. In summary, compound 18b with ideal PK profiles exhibited good activity in vitro and in vivo, and might be a promising drug candidate for the treatment of diabetes mellitus.

Design, synthesis and biological evaluation of novel peptides with anti-cancer and drug resistance-reversing activities.

Chemotherapy is an important approach used to treat cancer, but severe side effects and emerging drug resistance restrict its clinical application. In this present study, we found that peptide B1 showed specific cytotoxicity to tumor cells. Moreover, a helix-wheel plot predicted that the Ser14 in this peptide is located at the interface of the hydrophobic and hydrophilic faces of B1. Subsequently, we wondered whether replacing Ser14 would alter the activity of B1, and so a series of B1 analogs were synthesized where the Ser14 was replaced by amino acids with distinct physicochemical properties. Amongst them, peptides where Ser14 was substituted by a nonpolar and basic amino acid had improved anti-cancer activity. Further investigations revealed that B1 and its analogs were capable of penetrating into cytoplasm and triggering cytochrome C release from mitochondria, which ultimately resulted in apoptosis. Meanwhile, B1 and its analogs inhibited the migration of cancer cells. The peptides also acted against drug-resistant cells and had drug resistance-reversing effects. In conclusion, these peptides might be promising candidates for oncotherapy.

Discovery of Novel P-Glycoprotein-Mediated Multidrug Resistance Inhibitors Bearing Triazole Core via Click Chemistry

A novel series of P‐glycoprotein (P‐gp)‐mediated multidrug resistance (MDR) inhibitors bearing a triazol‐phenethyl‐tetrahydroisoquinoline scaffold were designed and synthesized via click chemistry. Most of the synthesized compounds showed higher reversal activity than verapamil (VRP). Among them, the most potent compound 5 showed a comparable activity with the known potent P‐gp inhibitor WK‐X‐34 with lower cytotoxicity (IC50s > 100 μm). Compared with VRP, compound 5 exhibited more potency in increasing drug accumulation in K562/A02 MDR cells. Moreover, compound 5 persisted longer chemo‐sensitizing effect (>24 h) than VRP (<6 h) with reversibility. Given the low intrinsic cytotoxicity and the potent reversal activity, compound 5 may represent a promising candidate for developing P‐gp‐mediated MDR inhibitor.

Exploration of 2-((Pyridin-4-ylmethyl)amino)nicotinamide Derivatives as Potent Reversal Agents against P-Glycoprotein-Mediated Multidrug Resistance

Overexpression of the ATP-binding cassette (ABC) transport proteins, like ABCB1, commonly referred to as P-glycoprotein (P-gp), initiates active efflux of a broad spectrum of unrelated chemotherapeutic drugs in structure and function, leading to chemotherapy failure. A series of 2-((pyridin-4-ylmethyl)amino)nicotinamide derivatives as potent reversal agents against P-glycoprotein-mediated multidrug resistance (MDR) were designed and synthesized. The majority of target compounds displayed great reversal potency, especially 9n. In-depth studies demonstrated 9n has high potency (EC50 = 119.6 ± 6.9 nM), low cytotoxicity, and long duration (>24 h) in reversing adriamycin (ADM) resistance in K562/A02 cells. 9n also improved the effects of other cytotoxic agents related to MDR, increased accumulation of ADM, interrupted P-gp-mediated Rh123 efflux function, and suppressed P-gp ATPase activity in K562/A02 MDR cells. The Western blot analysis indicated that the MDR reversal by 9n was not due to a decrease in protein expression. Besides, the effect of CYP3A4 was not influenced by 9n, avoiding the toxicity caused by drug interactions. The study yielded 9n with superior properties compared to the classical inhibitor verapamil (VRP) and leading compound apatinib.

Design, synthesis and biological evaluation of LBM-A5 derivatives as potent P-glycoprotein-mediated multidrug resistance inhibitors.

A novel series of P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) inhibitors with triazol-N-phenethyl-tetrahydroisoquinoline or triazol-N-ethyl-tetrahydroisoquinoline scaffold were designed and synthesized via click chemistry. Most of the synthesized compounds showed higher reversal activity than verapamil (VRP). Among them, the most potent compound 4 showed a comparable activity with the known potent P-gp inhibitor WK-X-34 with lower cytotoxicity toward K562 cells (IC50>100μM). Compared with VRP, compound 4 exhibited more potency in increasing drug accumulation in K562/A02 MDR cells. Moreover, compound 4 could significantly reverse MDR in a dose-dependent manner and also persist longer chemo-sensitizing effect than VRP with reversibility. Further mechanism studies revealed that compound 4 could remarkably increase the intracellular accumulation of Adriamycin (ADM) in K562/A02 cells as well as inhibit rhodamine-123 (Rh123) efflux from the cells. These results suggested that compound 4 may represent a promising candidate for developing P-gp-mediated MDR inhibitors.

Design, Synthesis, and Pharmacological Characterization of N-(4-(2 (6,7-Dimethoxy-3,4-dihydroisoquinolin-2(1H)yl)ethyl)phenyl)quinazolin-4-amine Derivatives: Novel Inhibitors Reversing P-Glycoprotein-Mediated Multidrug Resistance

P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) is a principal obstacle for successful cancer chemotherapy. A novel P-gp inhibitor with a quinazoline scaffold, 12k, was considered to be the most promising for in-depth study. 12k possessed high potency (EC50 = 57.9 ± 3.5 nM), low cytotoxicity, and long duration of activity in reversing doxorubicin (DOX) resistance in K562/A02 cells. 12k also boosted the potency of other MDR-related cytotoxic agents with different structures, increased accumulation of DOX, blocked P-gp-mediated Rh123 efflux, and suppressed P-gp ATPase activity in K562/A02 MDR cells. However, 12k did not have any effects on CYP3A4 activity or P-gp expression. In particular, 12k had a good half-life and oral bioavailability and displayed no influence on DOX metabolism to obviate the side effects closely related to increased plasma concentrations of cytotoxic agents in vivo.

Design, synthesis and evaluation of novel triazole core based P-glycoprotein-mediated multidrug resistance reversal agents.

A novel series of triazol-N-ethyl-tetrahydroisoquinoline based compounds were designed and synthesized via click chemistry. Most of the synthesized compounds showed P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) reversal activities. Among them, compound 7 with little cytotoxicity towards GES-1 cells (IC50 >80μM) and K562/A02 cells (IC50 >80μM) exhibited more potency than verapamil (VRP) on increasing anticancer drug accumulation in K562/A02 cells. Moreover, compound 7 could significantly reverse MDR in a dose-dependent manner and also persist longer chemo-sensitizing effect than VRP with reversibility. Further mechanism studies revealed that compound 7 in reversing MDR revealed that it could remarkably increase the intracellular accumulation of both rhodamine-123 (Rh123) and adriamycin (ADM) in K562/A02 cells as well as inhibit their efflux from the cells. These results suggested that compound 7 showed more potency than the classical P-gp inhibitor VRP under the same conditions, which may be a promising P-gp-mediated MDR modulator for further development.

Design, synthesis and biological evaluation of novel triazole-core reversal agents against P-glycoprotein-mediated multidrug resistance

We designed and synthesized a novel series of P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) inhibitors bearing a triazolphenethyl–tetrahydroisoquinoline scaffold through click chemistry. Then those synthesized compounds were tested on doxorubicin-resistant erythroleukemia K562/A02 cells in a series of experiments. The result is that most of the synthesized compounds exhibit more active MDR reversal activity than verapamil (VRP). However, among them, compound 11 exhibits less cytotoxicity (IC50s > 100 μM), but more potency than the known P-gp inhibitors WK-X-34 and VRP on increasing anticancer drug accumulation in K562/A02 cells. Moreover, this compound can not only maintain a longer chemo-sensitizing effect (>24 h) than VRP (<6 h) with reversibility, but also significantly reverses MDR in a dose-dependent manner. Therefore, considering the low intrinsic cytotoxicity but strong reversal activity in vitro, compound 11 may be a promising lead with a potent and safe resistance modulator in combinational cancer chemotherapy.