Lapatinib

 

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Biological Activity

Description	Lapatinib, used in the form of Lapatinib Ditosylate, is a potent EGFR and ErbB2 inhibitor with IC50 of 10.8 and 9.2 nM, respectively.
Targets	EGFR	ErbB2
IC50	10.8 nM	9.2 nM [1]
In vitro	Lapatinib weakly inhibits the activity of ErbB4 with IC50 of 367 nM, and displays >300-fold selectivity for EGFR and ErbB2 over other kinases such as c-Src, c-Raf, MEK, ERK, c-Fms, CDK1, CDK2, p38, Tie-2, and VEGFR2. Lapatinib significantly inhibits receptor autophosphorylation of EGFR and ErbB2 in a dose-dependent manner with IC50 of 170 nM and 80 nM, respectively in HN5 cells; as well as 210 nM and 60 nM, respectively in BT474 cells. Unlike OSI-774 and Iressa (ZD1839) which preferentially inhibit the growth of the EGFR-overexpressing cells, Lapatinib inhibits the growth of both EGFR- and ErbB2-overexpressing cells. Lapatinib displays higher inhibitory activity against EGFR- or ErbB2-overexpressing cells with IC50 of 0.09-0.21 μM, compared with cells expressing low levels of EGFR or ErbB2 with IC50 of 3-12 μM, and exhibits ~100-fold selectivity over the normal fibroblast cells. Lapatinib potently inhibits the outgrowth of EGFR-overexpressing HN5 and A-431 cells, as well as ErbB2-overexpressing BT474 and N87 cells, and significantly induces G1 arrest of HN5 cells and apoptosis of BT474 cells, which are associated with inhibition of AKT phosphorylation. [1]
In vivo	Oral administration of Lapatinib (~100 mg/kg) twice daily significantly inhibits the growth of BT474 and HN5 xenografts in a dose-dependent manner. [1]
Features

Protocol(Only for Reference)

Kinase Assay: ^[1]

In vitro kinase assays

The IC50 values for inhibition of enzyme activity are generated by measuring inhibition of phosphorylation of a peptide substrate. The intracellular kinase domains of EGFR and ErbB2 are purified from a baculovirus expression system. EGFR and ErbB2 reactions are performed in 96-well polystyrene round-bottomed plates in a final volume of 45 μL. Reaction mixtures contain 50 mM 4-morpholinepropanesulfonic acid (pH 7.5), 2 mM MnCl2, 10 μM ATP, 1 μCi of [γ33P] ATP/reaction, 50 μM Peptide A [Biotin-(amino hexonoic acid)-EEEEYFELVAKKK-CONH2], 1 mM dithiothreitol, and 1 μL of DMSO containing serial dilutions of Lapatinib beginning at 10 μM. The reaction is initiated by adding the indicated purified type-1 receptor intracellular domain. The amount of enzyme added is 1 pmol/reaction (20 nM). Reactions are terminated after 10 minutes at 23°C by adding 45 μL of 0.5% phosphoric acid in water. The terminated reaction mix (75 μL) is transferred to phosphocellulose filter plates. The plates are filtered and washed three times with 200 μL of 0.5% phosphoric acid. Scintillation cocktail (50 μL) is added to each well, and the assay is quantified by counting in a Packard Topcount. IC50 values are generated from 10-point dose-response curves.

Cell Assay: ^[1]

Cell lines	HFF, MCF-7, T47D, A-431, HN5, BT474, N87, CaLu-3, HB4a, and HB4a c5.2 cells
Concentrations	Dissolved in DMSO, final concentrations ~100 μM
Incubation Time	72 hours
Method	Cells are exposed to various concentrations of Lapatinib for 72 hours. Relative cell number is estimated using methylene blue staining. The absorbance at 620 nm is read in a Spectra microplate reader. Cell death and cell cycle analysis are assessed by propidium iodide staining and antibody detection of incorporated BrdUrd and staining with propidium iodide.

Animal Study: ^[1]

Animal Models	CD-1 nude female mice implanted s.c. with HN5 cells, and C.B-17 SCID female mice implanted s.c. with BT474 cells
Dosages	~100 mg/kg
Administration	Orally twice daily
Solubility	15% Captisol, 30 mg/mL

1

References

Clinical Trial Information( data from http://clinicaltrials.gov)

NCT Number	Recruitment	Conditions	Sponsor /Collaborators	Start Date	Phases
NCT01808573	Recruiting	HER2+ Metastatic Breast Cancer (MBC)	Puma Biotechnology, Inc.	2013-03	Phase 3
NCT01947023	Recruiting	Recurrent Thyroid Cancer	National Cancer Institute (NCI)	2013-08	Phase 1
NCT01875666	Recruiting	Breast Neoplasms	UNC Lineberger Comprehensive Cancer Center|Genentech|Susan G. Komen Breast Cancer Foundation|GlaxoSmithKline	2013-09	Phase 1
NCT01985893	Recruiting	Metastatic Breast Cancer	Berufsverband Niedergelassener Gyn kologischer Onkologen in Deutschland e.V.|OnkoDataMed GmbH	2013-09	Phase 2
NCT01973660	Recruiting	Breast Cancer	SOLTI Breast Cancer Research Group|GlaxoSmithKline	2013-10	Phase 2
NCT01934894	Recruiting	Metastatic Breast Cancer With Intracranial Metastases	SCRI Development Innovations, LLC|SCRI Development Innovations|GlaxoSmithKline|Sanofi	2013-11	Phase 2

Chemical Information

Download Lapatinib SDF

Chemical Name	N-(4-(3-fluorobenzyloxy)-3-chlorophenyl)-6-(5-((2-(methylsulfonyl)ethylamino)methyl)furan-2-yl)quinazolin-4-amine,di4-methylbenzenesulfonate

Preparing Stock Solutions

Stock Solution (1ml DMSO)	1mM	10mM	20mM	30mM
Mass(mg)	0.58106	5.8106	11.6212	17.4318

Customer Reviews (7)

Click to enlarge	Rating
	Source	ANTICANCER RESEARCH, 31, 3767-3774. Lapatinib purchased from Selleck
	Method	Real time PCR/Western Blot
	Cell Lines	SKBR3 cells
	Concentrations	2 μM
	Incubation Time	30 min
	Results	Both EGF and TGF-α significantly increased the level of CD44 mRNA expression . However, EGF- or TGF-α-induced CD44 mRNA expression was reduced by EGFR inhibitors …. EGF-induced CD44 protein expression was reduced by both AG1478 and lapatinib.

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  Consecutive targetable smart nanoprobe for molecular recognition of cytoplasmic microRNA in metastatic breast cancer. [Kim E, et al. ACS Nano 2012;6(10):8525-35]

  
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  The HER2 amplicon includes several genes required for the growth and survival of HER2 positive breast cancer cells. [Sahlberg KK, et al. Mol Oncol 2012;7(3):392-401]

  
  PubMed: 23253899