Tozasertib

Biological Activity

Tozasertib (VX-680, MK-0457) is a small-molecule Aurora kinase inhibitor. The Aurora kinases are essential for the regulation of chromosome segregation and cytokinesis during mitosis. Tozasertib (VX-680) blocks cell-cycle progression and induces apoptosis in a diverse range of human tumor types. Tozasertib (VX-680) effectively inhibits proliferation of several different cell lines of clear cell renal carcinoma (IC50s < 10 μM) and blocks the growth of tumors in a rodent model of cancer (80 mg/kg), inhibiting H3 histone phosphorylation, to an increase of apoptotic cells, and to morphological changes such as vacuolization and swelling of the cells and nuclei. The combination of VX-680 and histone deacetylase inhibitor SAHA had a synergistic effect on the proliferation of HUH6 cells. Tozasertib (VX-680) might improve treatment results in HB with increased Aurora kinase activity by inhibiting cell proliferation and induction of apoptosis.

Product Citations

• 

  J Hematol Oncol. 2017 Jun 8;10(1):115.

  SIX3, a tumor suppressor, inhibits astrocytoma tumorigenesis by transcriptional repression of AURKA/B
  Tozasertib purchased from AbMole

Customer Product Validations & Biological Datas

	Source	Journal of Hematology & Oncology (2017). Figure 7. VX680 (Abmole Bioscience)
	Method	CCK8 assay
	Cell Lines	U251, U87 and U118 cell lines
	Concentrations
	Incubation Time	48 and 72 h
	Results	We found that the U251-SIX3 cells showed less sensitivity to VX680 compared with the U251-CON cells (Fig. 7a). With increased expression of AURKA or AURKB and reduced expression of SIX3, the p53 mutant U251 cells were more sensitive to VX680 treatment, compared with the p53 wild-type U87 cells (Fig. 7b).

Protocol

Cell Experiment
Cell lines	SW620, K562, HL-60, MIA PaCa-2 and HCT116 cells
Preparation method	Analysis of cell proliferation and viability. Tumor cells were seeded in 96-well plates and incubated with VX-680 for 96 h. To measure DNA synthesis, 0.5 mCi of [3H]thymidine was added to each well 3 h before the end of the experiment. Cells were then collected, and the incorporated radioactivity was counted on a Wallac microplate beta-counter. Cell viability was assessed using Promega CellTiter 96AQ to measure MTS (3-(4,5 dimethylthiazol-2-yl)-5-(3- carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt) conversion.
Concentrations	1~10 μM
Incubation time	96 h

Animal Experiment
Animal models	female athymic NCr-nu mice HL-60, MIA PaCa-2 and HCT116 cells tumour xenograft model
Formulation	50% PEG 300 in 50 mM phosphate buffer
Dosages	q.4.d. at a dose of 12.5, 25, 50 and 75 mg/kg
Administration	i.v.

Conversion of different model animals based on BSA (Value based on data from FDA Draft Guidelines)

Species	Mouse	Rat	Rabbit	Guinea pig	Hamster	Dog
Weight (kg)	0.02	0.15	1.8	0.4	0.08	10
Body Surface Area (m2)	0.007	0.025	0.15	0.05	0.02	0.5
Km factor	3	6	12	8	5	20

Animal A (mg/kg) = Animal B (mg/kg) multiplied by	Animal B Km
	Animal A Km

For example, to modify the dose of Compound A used for a mouse (20 mg/kg) to a dose based on the BSA for a rat, multiply 20 mg/kg by the K_m factor for a mouse and then divide by the K_m factor for a rat. This calculation results in a rat equivalent dose for Compound A of 10 mg/kg.

Chemical Information

References

[1] Dewerth A, et al. Pediatr Surg Int. In vitro evaluation of the Aurora kinase inhibitor VX-680 for Hepatoblastoma.

[2] Fei F, et al. Mol Cancer Ther. Activity of the Aurora kinase inhibitor VX-680 against Bcr/Abl-positive acute lymphoblastic leukemias.

[3] Harrington EA, et al. Nat Med. VX-680, a potent and selective small-molecule inhibitor of the Aurora kinases, suppresses tumor growth in vivo.