title: Combating HER2-overexpressing breast cancer through induction of calreticulin exposure by Tras-Permut CrossMab.
abstract: Although trastuzumab has succeeded in breast cancer treatment, acquired resistance is one of the prime obstacles for breast cancer therapies. There is an urgent need to develop novel HER2 antibodies against trastuzumab resistance. Here, we first rational designed avidity-imporved trastuzumab and pertuzumab variants, and explored the correlation between the binding avidity improvement and their antitumor activities. After characterization of a pertuzumab variant L56TY with potent antitumor activities, a bispecific immunoglobulin G-like CrossMab (Tras-Permut CrossMab) was generated from trastuzumab and binding avidity-improved pertuzumab variant L56TY. Although, the antitumor efficacy of trastuzumab was not enhanced by improving its binding avidity, binding avidity improvement could significantly increase the anti-proliferative and antibody-dependent cellular cytotoxicity (ADCC) activities of pertuzumab. Further studies showed that Tras-Permut CrossMab exhibited exceptional high efficiency to inhibit the progression of trastuzumab-resistant breast cancer. Notably, we found that calreticulin (CRT) exposure induced by Tras-Permut CrossMab was essential for induction of tumor-specific T cell immunity against tumor recurrence. These data indicated that simultaneous blockade of HER2 protein by Tras-Permut CrossMab could trigger CRT exposure and subsequently induce potent tumor-specific T cell immunity, suggesting it could be a promising therapeutic strategy against trastuzumab resistance.
authors.affiliation: Department of Oncology; PLA General Hospital; PLA School of Medicine ; Beijing, People's Republic of China.
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Nursing Department; PLA General Hospital; PLA School of Medicine ; Beijing, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Nephrology; General Hospital of Jinan Military Command ; Jinan, People's Republic of China.
authors.forename: Moyan
authors.initials: M
authors.lastname: Liu
authors.affiliation: Medical Department; General Hospital of Jinan Military Command ; Jinan, People's Republic of China.
authors.forename: Lichao
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Oncology; PLA General Hospital; PLA School of Medicine ; Beijing, People's Republic of China.
authors.forename: RuiXia
authors.initials: R
authors.lastname: LingHu
authors.affiliation: Department of Pharmacy; General Hospital of Shenyang Military Command ; Shenyang, People's Republic of China.
authors.forename: Fan
authors.initials: F
authors.lastname: Feng
authors.affiliation: Department of Gastroenterology ; PLA 302 Hospital ; Beijing, People's Republic of China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Gao
authors.affiliation: Department of Oncology; PLA General Hospital; PLA School of Medicine ; Beijing, People's Republic of China.
authors.forename: Shunchang
authors.initials: S
authors.lastname: Jiao
authors.affiliation: PLA General Hospital; PLA School of Medicine ; Beijing, People's Republic of China ; Institute for Translational Medicine; Second Military Medical University ; Shanghai, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Oncology; PLA General Hospital; PLA School of Medicine ; Beijing, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Oncology; PLA General Hospital; PLA School of Medicine ; Beijing, People's Republic of China.
authors.forename: Junlan
authors.initials: J
authors.lastname: Yang
keywords: ADCC; CDR, complementarity determining region; CH1, constant heavy chain 1; CL, constant light chain; CRT, calreticulin; CrossMab; FCM, flow cytometry; HER, human epidermal growth factor receptor; HER2-ECD, extracellular domain of HER2; HER2-overexpressing breast cancer; LDH, lactate dehydrogenase; PBMCs, peripheral blood mononuclear cells; PI3K, phosphatidylinositol 3-kinase; SEC, size-exclusion chromatography; T cell immunity; antibody-dependent cellular cytotoxicity; calreticulin exposure; mAb, monoclonal antibody; pertuzumab; trastuzumab