The inventors have prepared a novel anti-Cath-D
antibody (F1M1) that can reduce
tumor growth in a Cath-D secreting basal-like TNBC
cell line with strong immune infiltration, without significant
toxicity. The F1M1
antibody prevents recruitment of immunosuppressive M2 polarized tumor-associated macrophages (TAMs) and induces activation of natural killer cells in the tumor, and the F1M1 also enhances activation of antitumor M1 polarized TAM, recruitment and maturation of conventional cDC1 dendritic cells in the tumor to promote
antigen presentation and reduce depletion marker expression of CD4 + and CD8 + T cells in the tumor and drainage
lymph nodes. It is worthy of noting that the affinity of the
antibody F1M1 to Cath-D is better than that of the antibody F1 prepared by the inventor in advance. The inventors also have prepared a novel Fc-optimized F1M1-Fc + human antibody which can promote ADCC induction of
cancer cells and CAF, improve anti-tumor
efficacy, and trigger recruitment, activation and cytotoxic activity of NK cells in tumors. The F1M1-Fc + F1M1-Fc + can inhibit the growth of MDA-MB-231 and SUM159 TNBC
cell xenografts and two TNBC-PDX (one of the TNBC-PDX is resistant to neoadjuvant
chemotherapy), and has no obvious
toxicity. In addition, the F1M1-Fc < + > improves the
treatment effect of the
paclitaxel and
enzalutamide combined
medicine. Thus, the present invention relates to anti-
cathepsin-D antibodies and their use in the treatment of
cancer, in particular
triple negative breast cancer.