SIBP-03 

SIBP-03 is a specifical anti-HER3 antibody. SIBP-03 binds strongly and specifically to recombinant HER3 protein. SIBP-03 inhibits HER3 activation, as well as the downstream PI3K/AKT signaling pathway. SIBP-03 exhibits anticancer activity against squamous cell carcinoma, non-small cell lung cancer, gastric cancer, and breast cancer. SIBP-03 synergistically enhances the antitumor activity of DS-8201 (HY-138298A) and Cetuximab (HY-P9905)^[1][2].

Human IgG2 kappa

Human IgG2 kappa, Isotype Control

Human

SIBP-03 (10^-4-10⁴ ng/mL) binds strongly and specifically to recombinant human HER3 protein, while no binding is detected with recombinant human EGFR, HER2 or HER4 proteins^[1].
SIBP-03 binds to HER3 on the surface of MC38/HER3 cells with overexpressed HER3, while no detectable binding is observed with HER3-negative MC38 cells^[1].
SIBP-03 (0.01-10 μg/mL; 24 h treatment of FaDu/BT-474 cells, with 2 h pre-incubation of cells stimulated by NRG1) effectively inhibits ligand-independent and ligand-dependent HER3 activation, as well as the downstream PI3K/AKT signaling pathway, in FaDu, BT-474, and NRG1-stimulated MCF7 and BT-474 cells^[1].
SIBP-03 (0.01-100 μg/mL; 120 h) exerts only weak antiproliferative effects on FaDu, A549, BT-474, SK-BR-3 and NCI-N87 cells, but potently inhibits NRG1-stimulated proliferation of MCF7 cells, with an inhibition rate of 74.8% after treatment at 100 μg/mL^[1].
SIBP-03 (10-100 μg/mL; 1 h) does not induce complement-dependent cytotoxicity in FaDu cells or HER3-overexpressing MC38/HER3 cells at concentrations of 10 and 100 μg/mL^[1].
SIBP-03 (10-100 μg/mL; 5 h) induces ADCC activity in MC38/HER3 cells overexpressing HER3, but fails to induce such activity in BT-474 cells at concentrations of 10 and 100 μg/mL^[1].
SIBP-03 (10-100 μg/mL; 5 h) induces antibody-dependent cellular phagocytosis activity in human breast cancer BT-474 cells and HER3-overexpressing MC38/HER3 cells at concentrations of 10 μg/mL and 100 μg/mL^[1].
SIBP-03 (30 μg/mL; 144 h) can synergistically enhance the antiproliferative activity of DS-8201 in SK-BR-3 and MDA-MB-453 cells^[2].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

SIBP-03 (0.2-2 mg/kg; i.v.) exhibits potent antitumor activity in FaDu xenograft mouse models, with a TGI of 116.3% at the dose of 2 mg/kg, and produces sustained inhibition of the HER3/AKT signaling pathway for up to 168 h after a single intravenous administration^[1].
SIBP-03 (6 mg/kg; i.v.) exhibits significant anti-tumor activity in the A549 xenograft mouse model, with a tumor growth inhibition (TGI) rate of 57.5% at the dose of 6 mg/kg^[1].
SIBP-03 (20 mg/kg; i.v.) exhibits significant antitumor activity in the NCI-N87 xenograft mouse model, with a tumor growth inhibition (TGI) rate of 50.8% at the dose of 20 mg/kg^[1].
Single treatment with SIBP-03 (0.6 mg/kg; i.v.) achieves a TGI of 96% in FaDu xenograft-bearing mice, while combination treatment with Cetuximab (HY-P9905) induces a TGI of 152% and causes tumor regression in 66.7% of treated mice^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

2065  [NCBI]

P21860

ERBB3/HER3

ELISA, FACS, Functional assay

Unconjugated

The product can be reconstituted/diluted with sterile PBS or saline.

[SIBP-03]

Please store the product under the recommended conditions in the Certificate of Analysis.

• [1]. Li WJ, et al. SIBP-03, a novel anti-HER3 antibody, exerts antitumor effects and synergizes with EGFR- and HER2-targeted drugs. Acta Pharmacol Sin. 2024;45(4):857-866.  [Content Brief]

  [2]. Li WJ, et al. HER3 upregulation reduces DS-8201 sensitivity in HER2-positive tumor cells by ATR/CHK1/FoxO1 signaling cascade. Acta Pharmacol Sin. 2026;47(2):481-492.  [Content Brief]