Pheophorbide a pha

Yttrium(III) chloride hexahydrate (YCl₃·6H₂O), erbium(III) chloride hexahydrate (ErCl₃·6H2O), ytterbium(III) chloride hexahydrate (YbCl₃·6H₂O), ammonium fluoride (NH₄F), 4-(dimethylamino) pyridine (DMAP), and triphosgene oleic acid were purchased from Aldrich Chemical Co. (Milwaukee, WI, USA). Sodium borohydride, N,N’-dicyclohexylarbodiimide (DCC), and N-hydroxysuccinimide (NHS) were obtained from Fluka (Buchs, Switzerland). 4-Hydroxy-2-butanone was purchased from TCI (Tokyo, Japan). α-Lipoic acid (LA), N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC), folic acid (FA), β-benzyl-L-aspartate (BLA), triethylamine (TEA), hydrazine monohydrate, PEG-bis(amine) (molecular weight: 3.350 kDa), sodium bicarbonate were purchased from Sigma Chemical Co. (St. Louis, MO, USA). Tetrahydrofuran (THF), n-hexane, benzene, N,N-dimethylformamide (DMF), methanol, chloroform, diethyl ether, dimethyl sulfoxide (DMSO), 1, 4-dioxane, acetic acid, and dichloromethane (DCM) were obtained from Samchun Pure Chemical Co., Ltd. (Gyeonggi-do, Korea). Pheophorbide a (Pha) was obtained from Frontier Scientific, Inc. (Logan, UT, USA).

5-ALA hydrochloride from Frontier Scientific Inc. (Logan, Utah) and rhodamine 123 from Life Technologies (Grand Island, New York) were dissolved in phosphate-buffered saline (PBS). Lapatinib, gefitinib, and sunitinib malate salt (all from LC Laboratories, Woburn, Massachusetts), PD169316 (from Millipore, Burlington, Massachusetts), pheophorbide a (Pha, from Frontier Scientific Inc.), Ko143 (from Santa Cruz Biotechnology, Santa Cruz, California) were all dissolved in DMSO. All chemicals were sterilized through $0.22\text{-}\mu \mathrm{m}$ filters and stored in a $-20°\mathrm{C}$ freezer.

Delta-aminolevulinic acid hydrochloride (ALA) from Frontier Scientific Inc. (Logan, UT) and rhodamine 123 from Life Technologies (Grand Island, NY) were dissolved in phosphate buffered saline (PBS) solution. Pheophorbide a (Pha) from Frontier Scientific Inc. and ABCG2 inhibitor Ko143 from Santa Cruz Biotechnology (Santa Cruz, CA) were dissolved in dimethyl sulfoxide (DMSO). All chemicals were sterilized through filters and stored in a −20 °C freezer.

Bosutinib (SKI-606), and C-14 radiolabeled bosutinib (C-14 bosutinib) were obtained from Pfizer Inc, New York, NY. Both drugs were dissolved in DMSO to obtain a 10-mM stock solution. Imatinib (STI-571, Gleevec) was synthesized by Enrico Rosso, PhD, University of Venice, Italy and was dissolved in water to obtain a 10-mM stock solution.
Doxorubicin (Sigma-Aldrich, Saint Louis, MO) was dissolved in DMSO to obtain a final concentration of 10 mM. Geneticin and puromycin, (Euroclone Milan, Italy) were both dissolved in water to obtain stock solutions of 400 mg/mL and 25 mg/mL, respectively.
Verapamil hydrochloride (Sigma-Aldrich, Saint Louis, MO) was dissolved in ethanol to obtain a final concentration of 100 mM and used as a selective ABCB1 inhibitor. Amantadine hydrochloride (Sigma-Aldrich, Saint Louis, MO) was dissolved in ethanol to obtain a final concentration of 1 M and used as a selective SLC22A1 inhibitor. Fumitremorgin C (FTC) (Sigma-Aldrich, Saint Louis, MO) was dissolved in DMSO to obtain a final concentration of 1 mM and used as a selective ABCG2 inhibitor.
Rhodamine 123 (Rho-123) (Sigma-Aldrich, Saint Louis, MO), 4-Di-2-ASP (4-(4-Diethylaminostyryl)-1-methylpyridinium iodide, ASP) (Invitrogen, Carlsbad, CA), and Pheophorbide A (PhA) (Frontier Scientific, Logan, UT) were dissolved in DMSO to obtain a final concentration of 2 mM, 10 mM, and 1 mM, respectively.