NVP-BEP800

Biological Activity

NVP-BEP800 (VER-82576) is an ATP-competitive HSP90β inhibitor. Heat shock protein 90 (Hsp90) is a ubiquitously expressed molecular chaperone with ATPase activity involved in the conformational maturation and stability of key signaling molecules involved in cell proliferation, survival, and transformation. NVP-BEP800 (VER-82576) showed activity against a panel of human tumor cell lines and primary human xenografts in vitro at nanomolar concentrations. In A375 melanoma and BT-474 breast cancer cell lines, NVP-BEP800 induced client protein degradation (including ErbB2, B-Raf(V600E), Raf-1, and Akt) and Hsp70 induction. Oral administration of NVP-BEP800 was well tolerated and induced robust antitumor responses in tumor xenograft models, including regression in the BT-474 breast cancer model. In these tumor models, NVP-BEP800 modulated Hsp90 client proteins and downstream signaling pathways at doses causing antitumor activity. NVP-BEP800 (VER-82576) showed in vivo activity in a variety of dosing regimens covering daily to weekly schedules, potentially providing a high degree of flexibility in dose and schedule within the clinical setting. NVP-BEP800 can radiosensitise tumour cell lines of different entities through destabilisation and depletion of several Hsp90 client proteins, thus causing the depletion of S phase and G2/M arrest, increased DNA damage and repair protraction and, to some extent, apoptosis.

Protocol

Cell Experiment
Cell lines	BT-474, SKBr3, MCF-7, MDA-MB-157, MDA-MB-231, MDA-MB-468 and BT20 cells line
Preparation method	Cell proliferation was determined using either sulforhodamine B for adherent cells or MTS assay for suspension cells or those showing low adherence. GI50 was the compound concentration that inhibits cell growth by 50% compared with vehicle control.
Concentrations	0~1 μ M
Incubation time	24 h

Animal Experiment
Animal models	T-474 tumor xenografts in nude mice
Formulation	0.5% methyl cellulose
Dosages	30 mg/kg qd for 2 weeks
Administration	PO.

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] Stingl L, et al. Br J Cancer. Novel HSP90 inhibitors, NVP-AUY922 and NVP-BEP800, radiosensitise tumour cells through cell-cycle impairment, increased DNA damage and repair protraction.

[2] Massey AJ, et al. Mol Cancer Ther. Preclinical antitumor activity of the orally available heat shock protein 90 inhibitor NVP-BEP800.