PCI-32765

Biological Activity

PCI-32765, a selective, irreversible Btk inhibitor, is a novel, molecularly targeted agent for patients with B-cell malignancies, and is particularly active in patients with CLL. B-cell receptor (BCR) signaling is a critical pathway in the pathogenesis of several B-cell malignancies, including chronic lymphocytic leukemia (CLL), and can be targeted by inhibitors of BCR-associated kinases, such as Bruton tyrosine kinase (Btk). PCI-32765 significantly inhibited CLL cell survival, DNA synthesis, and migration in response to tissue homing chemokines (CXCL12, CXCL13). PCI-32765 also down-regulated secretion of BCR-dependent chemokines (CCL3, CCL4) by the CLL cells, both in vitro and in vivo. In an adoptive transfer TCL1 mouse model of CLL, PCI-32765 affected disease progression. In this model, PCI-32765 caused a transient early lymphocytosis, and profoundly inhibited CLL progression, as assessed by weight, development, and extent of hepatospenomegaly, and survival. Inhibition of BTK by PCI-32765 overcomes BCR- and chemokine-controlled integrin-mediated retention and homing of malignant B cells in their growth- and survival-supporting lymph node and bone marrow microenvironment, which results in clinically evident CLL regression.

Product Citations

• 

  BMC Biol. 2021 May 20;19(1):108.

  Very long intergenic non-coding (vlinc) RNAs directly regulate multiple genes in cis and trans
  PCI-32765 purchased from AbMole

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  J Virol. 2020 Feb 14;94(5):e01791-19.

  Targeting Kaposi's Sarcoma-Associated Herpesvirus ORF21 Tyrosine Kinase and Viral Lytic Reactivation by Tyrosine Kinase Inhibitors Approved for Clinical Use
  PCI-32765 purchased from AbMole

Customer Product Validations & Biological Datas

	Source	Blood (2011). Figure 3. PCI-32765
	Method	Western Bolt
	Cell Lines	CD19+ cells
	Concentrations	10 μM
	Incubation Time	8 h
	Results	We found that inhibition of caspase activity by z-VAD-fmk completely prevented the induction of apoptosis provided by PCI-32765 concurrent with a decrease in cleaved PARP expression and a decrease in enzymatic activity of caspase-3

	Source	Blood (2011). Figure 2. PCI-32765
	Method	MTT assay
	Cell Lines	CD19+ cells
	Concentrations	10 μM
	Incubation Time	12-72 h
	Results	We found that there were no significant differences in PCI-32765–induced cell death based on interphase cytogenetic analysis

Protocol

Cell Experiment
Cell lines	osteoblast cells
Preparation method	In vitro osteoblast differentiation Cells derived from calvaria were cultured in an osteogenic medium (50 μM ascorbic acid, 10 nM dexamethasone and 10 mM β- glycerophosphate) in the presence of ibrutinib and subjected to an analysis of the activity of alkaline phosphatase (after 7 days) and bone nodule formation (after 21 days).
Concentrations	0~100nM
Incubation time	7days

Animal Experiment
Animal models	RANKL-induced bone loss in mice
Formulation	saline
Dosages	6.25, 12.5 or 25 mg/kg 1 h before the first GST-RANKL injection
Administration	oral gavage

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] Advani RH, et al. J Clin Oncol. Bruton tyrosine kinase inhibitor ibrutinib (PCI-32765) has significant activity in patients with relapsed/refractory B-cell malignancies.

[2] de Rooij MF, et al. Blood. The clinically active BTK inhibitor PCI-32765 targets B-cell receptor- and chemokine-controlled adhesion and migration in chronic lymphocytic leukemia.

[3] Chang BY, et al. Arthritis Res Ther. The Bruton tyrosine kinase inhibitor PCI-32765 ameliorates autoimmune arthritis by inhibition of multiple effector cells.

[4] Honigberg LA, et al. Proc Natl Acad Sci U S A. The Bruton tyrosine kinase inhibitor PCI-32765 blocks B-cell activation and is efficacious in models of autoimmune disease and B-cell malignancy.