Axially Substituted Silicon Phthalocyanine Payloads for Antibody–Drug Conjugates

Abstract

IR700, a silicon phthalocyanine (SiPc) photosensitizer, is an antibody–drug conjugate payload used clinically. It is, however, the sole SiPc payload to date, possibly due to the difficulty of its synthesis, resulting from its asymmetric phthalocyanine skeleton. Here, we report a new axially substituted SiPc payload that is more easily synthesized. Trastuzumab conjugated with the SiPc showed light- and antigen-dependent cytotoxicity in HER2-overexpressing cancer cell lines.

Key words

phthalocyanines - antibody–drug conjugates - photodynamic therapy - cancer - medicinal chemistry

Publikationsverlauf

Eingereicht: 19. April 2021

Angenommen nach Revision: 08. Mai 2021

Accepted Manuscript online:
08. Mai 2021

Artikel online veröffentlicht:
28. Mai 2021

• References and Notes

• 1 Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre LA, Jemal A. CA Cancer J. Clin. 2018; 68: 394
• 2 Khongorzul P, Ling CJ, Khan FU, Ihsan AU, Zhang J. Mol. Cancer Res. 2020; 18: 3
• 3a Maderna A, Leverett CA. Mol. Pharmaceutics 2015; 12: 1798
• 3b Lopus M, Oroudjev E, Wilson L, Wilhelm S, Widdison W, Chari R, Jordan MA. Mol. Cancer Ther. 2010; 9: 2689
• 4a Bross PF, Beitz J, Chen G, Chen XH, Duffy E, Kieffer L, Roy S, Sridhara R, Rahman A, Williams G, Pazdur R. Clin. Cancer Res. 2001; 7: 1490
• 4b Elgersma RC, Coumans RG. E, Huijbregts T, Menge WM. P. B, Joosten JA. F, Spijker HJ, de Groot FM. H, van der Lee MM. C, Ubink R, van den Dobbelsteen DJ, Egging DF, Dokter WH. A, Verheijden GF. M, Lemmens JM, Timmers CM, Beusker PH. Mol. Pharmaceutics 2015; 12: 1813
• 5 Mitsunaga M, Ogawa M, Kosaka N, Rosenblum LT, Choyke PL, Kobayashi H. Nat. Med. 2011; 17: 1685
• 6 Peng X, Draney DR, Chen J. US 7005518, 2004
• 7 Li X, Zheng B.-D, Peng X.-H, Li S.-Z, Ying J.-W, Zhao Y, Huang J.-D, Yoon J. Coord. Chem. Rev. 2019; 379: 147
• 8 Sato K, Ando K, Okuyama S, Moriguchi S, Ogura T, Totoki S, Hanaoka H, Nagaya T, Kokawa R, Takakura H, Nishimura M, Hasegawa Y, Choyke PL, Ogawa M, Kobayashi H. ACS Cent. Sci. 2018; 4: 1559

For examples of targeted silicon phthalocyanines, see
• 9a Li K, Dong W, Liu Q, Lv G, Xie M, Sun X, Qiu L, Lin J. J. Photochem. Photobiol., B 2019; 190: 1
• 9b Li K, Qiu L, Liu Q, Lv G, Zhao X, Wang S, Lin J. J. Photochem. Photobiol., B 2017; 174: 243
• 9c Zheng Y.-W, Chen S.-F, Zheng B.-Y, Ke M.-R, Huang J.-D. Chem. Lett. 2014; 43: 1701
• 10 Kobayashi H, Choyke PL. Acc. Chem. Res. 2019; 52: 2332
• 11 Silicon phthalocyanine dihydroxide can be synthesized from unsubstituted 1,3-diiminoisoindoline and silicon tetrachloride in a single step in 79% yield; see: Ishidai K, Ookubo K. EP 2644660, 2012

For selected examples of silicon phthalocyanines possessing reactive functionalities as axial ligands, see ref. 9a and:
• 12a Cheng Y, Doane TL, Chuang C.-H, Ziady A, Burda C. Small 2014; 10: 1799
• 12b Galstyan A, Kauscher U, Block D, Ravoo BJ, Strassert CA. ACS Appl. Mater. Interfaces 2016; 8: 12631
• 12c Martín-Gomis L, Peralta-Ruiz F, Thomas MB, Fernández-Lázaro F, D’Souza F, Sastre-Santos Á. Chem. Eur. J. 2017; 23: 3863
• 12d Szuwarzyński M, Wolski K, Pomorska A, Uchacz T, Gut A, Łapok Ł, Zapotoczny S. Chem. Eur. J. 2017; 23: 11239
• 13 Kobayashi M, Harada M, Takakura H, Ando K, Goto Y, Tsuneda T, Ogawa M, Taketsugu T. ChemPlusChem 2020; 85: 1959
• 14 Conjugation of NHS-SiPcs with Antibodies; General Procedure Trastuzumab (8.0 mg; Roche) was purified by using a PD Minitrap G-25 column with pH 8.0 phosphate buffer to afford a 7.7 mg/mL trastuzumab solution. To 100 μL of this solution was added a solution of NHS-SiPc (50 nmol) in DMSO (20 μL), and the mixture was stirred at rt in darkness for 12 h. The mixture was then purified twice on a PD Minitrap G-25 column with phosphate-buffered saline (PBS) to afford an Ab-SiPc stock solution.
• 15 In Vitro Phototoxicity Studies The phototoxicities of Ab-NuSiPc, Ab-CyaSiPc, and Ab-IR700 were quantified by using Cell Counting Kit-8 (Dojindo Molecular Technologies, Inc.) according to the method described in the manufacturer’s manual. Briefly, ten thousand cells per well with 50 μL of medium were seeded into 96-well plates and cultured overnight. Subsequently, the cells were separately incubated for 24 h at 37 °C with the addition of 50 μL of various concentrations of Ab-NuSiPc, Ab-CyaSiPc, or Ab-IR700, prepared by three-times sequential dilution from 20 μg mL^–1. The drug-containing medium was then removed and the cells were washed with PBS once, and fresh medium was added. The cells were irradiated from the bottom of the 96-wells plate with a 690 nm LED lamp (Yamato Scientific Co., Ltd.) at 100 J cm^–2 at rt. After 24 h, Cell Counting Kit-8 reagent was added at 10 μL per well and the cells were incubated for 1.5 h. The absorbance of the samples was then measured on an iMark™ Microplate Absorbance Reader (BIO-RAD) with a 450 nm-wavelength filter.