A-1331852

Biological Activity

In vitro: A-1331852 selectively disrupts BCL-XL–BIM complexes and induces the hallmarks of apoptosis in BCL-XL–dependent Molt-4 cells with IC50s in the low nanomolar range but does not affect MEF cells lacking BAK or BAX. In CellTiter-Glo cell viability assay, A-1331852 inhibits NCI-H847, NCI-H1417, SET-2, HEL, OCI-M2 with EC50 values of 3, 7, 80, 120 and 100 nM.

In vivo: A-1331852 demonstrates antitumor efficacy in the Molt-4 xenograft model, inducing tumor regressions as a single agent. Additionally, A-1331852 combines with venetoclax to recapitulate the efficacy of navitoclax in the NCI-H1963.FP5 xenograft model of SCLC. A-1331852 significantly inhibits tumor growth in seven subcutaneous xenograft models of solid tumors, including breast cancer, NSCLC, and ovarian cancer.

Protocol

Cell Experiment
Cell lines	bone marrow cells
Preparation method	5 × 104 bone marrow cells were cultured for 4 or 24 h with or without the BCL-XL inhibitor A-1331852 in a 96-well plate in 100 μl of medium. Plates were allowed to equilibrate at room temperature prior to adding 100 μl Caspase-9 Glo reagent
Concentrations	1 μM
Incubation time	4 or 24 h

Animal Experiment
Animal models	SCID-bg mice
Formulation
Dosages	25 mg/kg
Administration	orally

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 resveratrol used for a mouse (22.4 mg/kg) to a dose based on the BSA for a rat, multiply 22.4 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 resveratrol of 11.2 mg/kg.

Chemical Information

References

Targeting senescent cholangiocytes and activated fibroblasts with B-cell lymphoma-extra large inhibitors ameliorates fibrosis in multidrug resistance 2 gene knockout (Mdr2-/- ) mice.
Moncsek A, et al. Hepatology. 2018 Jan;67(1):247-259. PMID: 28802066.

The BH3-only proteins BIM and PUMA are not critical for the reticulocyte apoptosis caused by loss of the pro-survival protein BCL-XL.
Delbridge AR, et al. Cell Death Dis. 2017 Jul 6;8(7):e2914. PMID: 28682312.