Lapatinib Ditosylate

Biological Activity

Lapatinib Ditosylate is a selective and effective inhibitor of ErbB-2 and EGFR dual tyrosine kinases. ErbB-2 and EGFR dual tyrosine kinases are growth promoting factors that are over expressed in some breast cancer cell lines. Lapatinib inhibits the growth of both EGFR- and ErbB-2-overexpressing cells, whereas OSI-774 and Iressa which are EGFR selective inhibitors preferentially inhibit the growth of the EGFR-overexpressing cell lines. Research studies have reported that Lapatinib Ditosylate can inhibit breast cancer cell proliferation.

Product Citations

• 

  Cell Death Dis. 2021 Feb 15;12(2):179.

  Targeting transcription of MCL-1 sensitizes HER2-amplified breast cancers to HER2 inhibitors
  Lapatinib Ditosylate purchased from AbMole

• 

  Proc Natl Acad Sci U S A. 2018 Feb 23.

  Coamplification of miR-4728 protects HER2-amplified breast cancers from targeted therapy
  Lapatinib Ditosylate purchased from AbMole

• 

  J Pharm Pharm Sci. 2016 Feb;404-407.

  Phase dependent discrepancy in murine vaginal micro-environment: A correlative analysis of PH, glycogen and Serum Estrogen upon exposure to Lapatinib Ditosylate
  Lapatinib Ditosylate purchased from AbMole

Customer Product Validations & Biological Datas

	Source	Proc Natl Acad Sci U S A (2018) . Figure 6. Lapatinib Ditosylate (AbMole BioScience)
	Method	i.v.
	Cell Lines	NSG mice
	Concentrations	100 mg/kg
	Incubation Time	5 d
	Results	Again, the single agents displayed modest activity, inhibiting tumor growth, whereas the combination shrank most of the tumors, similar to the BT-474 xenograft model.

	Source	Proc Natl Acad Sci U S A (2018) . Figure 5. Lapatinib Ditosylate (AbMole BioScience)
	Method	Western blotting
	Cell Lines	HCC-1419 and MDA-MB-453 cells
	Concentrations	1 μM
	Incubation Time	6, 12, and 24 h
	Results	To verify that both MCL-1:BIM and MCL-1:BAK complexes were disrupted by S63845, we immunoprecipitated MCL-1 complexes in lysates of the HER2-amplified breast cancer cells, HCC- 1419 and MDA-MB-453, following treatment with lapatinib, S63845 (at two concentrations of 300 nM and 1 μM), or their combination.

	Source	Proc Natl Acad Sci U S A (2018) . Figure 4. Lapatinib Ditosylate (AbMole BioScience)
	Method	Western blotting
	Cell Lines	MDA-MB-361 and BT-474 cells
	Concentrations	1 μM
	Incubation Time	24 h
	Results	Importantly, since HER2 inhibitors like lapatinib block ERK signaling in HER2-amplified breast cancers, it is likely that miR-4728 only has an antagonistic effect in the presence of HER2 inhibitors, while miR-4728 likely promotes tumorigenesis in the absence of HER2 inhibition.

	Source	Int J Pharm Pharm Sci (2016). Figure 3.Lapatinib (Abmole)
	Method	PH test
	Cell Lines
	Concentrations
	Incubation Time	1~21 days
	Results	No significant changes in the vaginal pH were observed between control and treated animals throughout the three phases of the estrous cycle. Even though, on the 12th d, prolonged diestrus phase in treated group animals was evidenced with the vaginal pH as compared with the control mice [fig. 3].

Protocol (for reference only)

Cell Experiment
Cell lines	HFF; BT474, MCF-7, N87, and CaLu-3; HN5, A-431, T47D, HB4a, and HB4a c5.2 cell lines
Preparation method	In Vitro Growth Inhibition Assays For assessment of cell-based potency, cells were plated in 96-well Falcon plates (Becton Dickinson) in the growth media described above. Plating densities that resulted in logarithmic growth of vehicle-treated cells for the duration of the assay were used: HFF, 15,000 cells/cm2; BT474, MCF-7, N87, and CaLu-3, 30,000 cells/cm2; and HN5, A-431, T47D, HB4a, and HB4a c5.2, 10,000 cells/cm2. After 24 h, cells were exposed to compounds at the concentrations indicated in Fig. 2. HFF, BT474, HN5, and N87 cells were treated in low-glucose DMEM containing 5% FBS, 50 μg/ml gentamicin, and 0.3% v/v DMSO. MCF-7 cells were treated in 50% high-glucose DMEM, 50% low-glucose DMEM containing 5% FBS, 50 μg/ml gentamicin, and 0.3% v/v DMSO. T47D, A-431, and CaLu-3 cells were treated in 50% RPMI, 50% low-glucose DMEM containing 5% FBS, 50 μg/ml gentamicin, and 0.3% v/v DMSO. HB4a and HB4a c5.2 cells were treated in 50% DMEM, 50% RPMI 1640 supplemented with 5% FBS, 2.5 μg/ml hydrocortisone, 2.5 μg/ml insulin, 25 μg/ml hygromycin B, 50 μg/ml gentamicin, and 0.3% v/v DMSO. After 3 days, relative cell number was estimated using methylene blue staining. The media were removed, and 100 μl of 0.5% w/v methylene blue dissolved in 50% ethanol and 50% water were added to each well. Plates were washed by immersion in deionized water and allowed to air dry. 1% w/v n-lauroylsarcosine (100 μl) dissolved in PBS was added to each well, and plates were incubated for 30 min at room temperature. The absorbance at 620 nm was read in a Spectra (Tecan) microplate reader. Data were analyzed using curve-fitting macros written for Microsoft Excel. Concentrations with IC50 were interpolated using the method of Levenberg and Marquardt and this equation: y = Vmax × [1 − (xn/(Kn + xn))], where “K” is equal to IC50.
Concentrations	0~100 μM
Incubation time	3 days

Animal Experiment
Animal models	CD-1 nude female mice were used for HN5 human tumor xenografts, C.B-17 SCID female mice were used for BT474 human tumor xenografts
Formulation	sulfo-butyl-ether-β-cyclodextrin 10% aqueous solution (CD10)
Dosages	30 or 100 mg/kg twice daily for 21 days
Administration	p.o.

Chemical Information

Molecular Weight	925.46
Formula	C29H26ClFN4O4S.2C7H8O3S
CAS Number	388082-78-8
Solubility (25°C)	DMSO 90 mg/mL
Storage	-20°C, sealed, protect from light

Conversion of different model animals based on BSA (PMID: 27057123)

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.

References

[1] Simonelli M, et al. Eur J Cancer. Phase I pharmacokinetic and pharmacodynamic study of lapatinib in combination with sorafenib in patients with advanced refractory solid tumors.

[2] Bachelot T, et al. Lancet Oncol. Lapatinib plus capecitabine in patients with previously untreated brain metastases from HER2-positive metastatic breast cancer (LANDSCAPE): a single-group phase 2 study.

[3] Jegg AM, et al. Breast Cancer Res Treat. PI3K independent activation of mTORC1 as a target in lapatinib-resistant ERBB2+ breast cancer cells.

[4] de Jonge MJ, et al. Invest New Drugs. Phase I and pharmacokinetic study of pazopanib and lapatinib combination therapy in patients with advanced solid tumors.

[5] Rusnak DW, et al. Mol Cancer Ther. The effects of the novel, reversible epidermal growth factor receptor/ErbB-2 tyrosine kinase inhibitor, GW2016, on the growth of human normal and tumor-derived cell lines in vitro and in vivo.