An anti‑TROP2 monoclonal antibody TrMab‑6 exerts antitumor activity in breast cancer mouse xenograft models

Abstract

Trophoblast cell surface antigen 2 (TROP2), reported to be overexpressed in several types of cancer, is involved in cell proliferation, invasion, metastasis, and poor prognosis of many types of cancer. Previously, a highly sensitive anti-TROP2 monoclonal antibody (clone TrMab-6; mouse IgG 2b , κ) was developed using a Cell-Based Immunization and Screening (CBIS) method. TrMab-6 was useful for investigations using flow cytometry, western blot, and immunohistochemistry. The aim of the present study was to investigate whether TrMab-6 possesses in vitro antibody-dependent cellular cytotoxicity (ADCC) or complement-dependent cytotoxicity (CDC) activities or in vivo antitumor activities using mouse xenograft models of TROP2-overexpressed CHO-K1 (CHO/TROP2) and breast cancer cell lines, including MCF7, MDA-MB-231, and MDA-MB-468. In vitro experiments revealed that TrMab-6 strongly induced ADCC and CDC activities against CHO/TROP2 and the three breast cancer cell lines, whereas it did not show those activities against parental CHO-K1 and MCF7/TROP2-knockout cells. Furthermore, in vivo experiments on CHO/TROP2 and MCF7 xenografts revealed that TrMab-6 significantly reduced tumor growth, whereas it did not show antitumor activities against parental CHO-K1 and MCF7/TROP2-knockout xenografts. The findings suggest that TrMab-6 is a promising treatment option for TROP2-expressing breast cancers.

Defucosylated mouse‑dog chimeric anti‑HER2 monoclonal antibody exerts antitumor activities in mouse xenograft models of canine tumors

“…Canine mononuclear cells (MNCs) obtained from Yamaguchi University were resuspended in DMEM (Nacalai Tesque, Inc.) with 10% FBS and were used as effector cells (37,38,42). Target cells (CHO-K1, CHO/dHER2, and SNP) were labeled with 10 µg/ml Calcein AM (Thermo Fisher Scientific, Inc.) (31,(39)(40)(41)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53). The target cells (2x10 4 cells) were plated in 96-well plates and mixed with effector canine MNCs (effector/target cells ratio, 50), 100 µg/ml of H77Bf or control dog IgG.…”

“…CDC of H77Bf. Target cells (CHO-K1, CHO/dHER2, and SNP) were labeled with 10 µg/ml Calcein AM (31,(39)(40)(41)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53). The target cells (2x10 4 cells) were plated in 96-well plates and mixed with rabbit complement (final dilution 1:10; Low-Tox-M Rabbit Complement; Cedarlane Laboratories,) and 100 µg/ml of control dog IgG or H77Bf.…”

Defucosylated Mouse–Dog Chimeric Anti-EGFR Antibody Exerts Antitumor Activities in Mouse Xenograft Models of Canine Tumors

“…ADCC assay was performed as previously described [ 16 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Briefly, canine mononuclear cells derived from dog blood were obtained from Yamaguchi University and resuspended in DMEM with 10% FBS to be used as effector cells.…”

Antitumor Activity of an anti-EGFR/HER2 Bispecific Antibody in a Mouse Xenograft Model of Canine Osteosarcoma

“…Canine mononuclear cells (MNCs) obtained from Yamaguchi University were resuspended in DMEM (Nacalai Tesque, Inc.) with 10% FBS and were used as effector cells. Target D-17 cells were labeled with 10 μg/mL Calcein AM (Thermo Fisher Scientific, Inc.) [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. The target cells (2 × 10 4 cells) were plated in 96-well plates and mixed with effector canine MNCs (effector/target cells ratio, 50), 100 μg/mL of control normal dog IgG, E134Bf, H77Bf, and E134Bf-H77scFv.…”

“…Target D-17 cells were treated with 10 μg/mL calcein AM [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. The target cells (2 × 10 4 cells) were mixed with rabbit complement (final dilution 1:10; Low-Tox-M Rabbit Complement; Cedarlane Laboratories) and 100 μg/mL of control normal dog IgG, E134Bf, H77Bf, and E134Bf-H77scFv.…”