Apatinib (YN968D1) mesylate

Apatinib (YN968D1) is a novel, orally bioavailable, selective inhibitor with potential antiangiogenic and antineoplastic activities. Apatinib selectively binds to and inhibits VEGFR2. Apatinib can also potently suppress the activities of Ret, c-kit and c-src with IC50 of 0.013 μM, 0.429 μM and 0.53 μM, respectively. Apatinib inhibits cellular phosphorylation of VEGFR-2, c-kit and PDGFRβ. Apatinib significantly inhibits proliferation stimulated by 20 ng/mL VEGF (IC50 = 0.17μM). Apatinib effectively inhibits proliferation, migration and tube formation of human umbilical vein endothelial cells induced by FBS, and blocked the budding of rat aortic ring. ^[1] Apatinib reverses ABCB1- and ABCG2-mediated MDR by inhibiting their transport function, but not by blocking the AKT or ERK1/2 pathway or downregulating ABCB1 or ABCG2 expression. Apatinib significantly potentiates the cytotoxicity of established ABCB1 and ABCG2 substrates and increased the accumulation of DOX and Rho 123 in ABCB1- or ABCG2-overexpressing cells. Furthermore, apatinib significantly inhibited the photoaffinity labeling of both ABCB1 and ABCG2 with [¹²⁵I]iodoarylazidoprazosin in a concentration-dependent manner. ^[2]

Apatinib inhibits the growth of a broad range of human tumor xenografts in a significant dose-dependent manner. ^[1] Apatinib reverses ABCB1-mediated MDR in the nude mouse xenograft model. ^[2] Apatinib significantly enhances the antitumor activity of doxorubicin in nude mice bearing K562/ADR xenografts. ^[3]

• Enzyme-linked immunosorbent assay

  A poly(glu, ala, tyr) 6:3:1 random copolymer is used as a tyrosine containing substrate solution. The substrate is stored as a 1 mg/mL stock in PBS at −20 °C and diluted 1 in 500 with PBS in order to coat 96 well plates (100 μL/well). Plates are coated on the day prior to assay, sealed with adhesive seals, and stored overnight at 4 °C. On the day of the assay, the substrate solution is discarded and the assay plate wells are washed once with PBST (PBS containing 0.05% v/v Tween 20) and once with Hepes buffer (50 mM, pH 7.4).Test compounds are diluted with 10% DMSO de-ionized water and 25 μL volumes transferred to wells in the washed assay plates. Manganese chloride solution (40 mM) containing 8 μM ATP is then added (25 μL) to all test wells. Control and blank wells, containing compound diluent and manganese chloride solution with and without ATP, respectively, are also included to determine the dynamic range of the assay. Freshly diluted enzyme (50 μL) is added to each well, and the plates incubated at room temperature for 20 min. The liquid is then discarded and the wells are washed twice with PBST. Mouse IgG anti-phosphotyrosine antibody diluted 1:6000 with PBST containing 0.5% (w/v) bovine serum albumin (BSA) is added (100 μL/well), and the plates incubated for 1h at room temperature before discarding the liquid and washing the wells twice with PBST. Horseradish peroxidase (HRP)-linked sheep anti-mouse Ig antibody diluted 1:500 with PBST containing 0.5% (w/v) BSA, is then added (100 μL/well) and the plates incubated for a further 1 h at room temperature before discarding the liquid and washing the wells twice with PBST. A 1 mg/mL solution of 2,2‘-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid is freshly prepared in 50 mM phosphate-citrate buffer (pH5.0) containing 0.03% (w/v) sodium perborate, and 100 μL added to each well. Plates are then incubated for 20−60 min at room temperature until the optical density value of control wells measured at 405 nm is approximately 1.0. IC50 values for compound enzyme inhibition are interpolated using Microcal Origin following subtraction of blank values.

• Cell lines

  HUVEC

• Concentrations

  ~25 μM

• Incubation Time

  72 h

• Method

  The HUVEC are seeded into 96-well plates. After 24 h of incubation, cells are exposed to the test agents (vehicle as control) together with 20 ng/mL VEGF or 20% FBS for another 72 h. After fixation with 10% trichloroacetic acid, the cells are stained with 0.4% sulforhodamine B for 30 min at 37 °C and then washed with 1% acetic acid. Tris is added to dissolve the complex, and the optical density is measured at 520 n

• Animal Models

  Ls174t, HCT 116, SGC-7901, HT-29, A549, NCI-H460 xenografted BALB/cA nude mice

• Dosages

  50, 100, 200 mg/kg

• Administration

  p.o.