Abstract 6174: Developing a novel antibody drug conjugate against cervical cancer

Abstract Background: Cervical cancer ranks fourth in incidence and mortality among female tumors, with over 0.6 million patients diagnosed worldwide in 2020. A large percentage of cervical cancer patients will develop advanced diseases (stage IV or recurrent disease) and the 5-year survival rate of these patients was only 15-20% due to the lack of efficacy and adverse effects of first line chemodrugs. Recently, antibody drug conjugates (ADCs) emerge as a novel class of targeted therapeutics that selectively ablate tumor cells without damaging normal organs and tissues, which has shown promising efficacy in treating solid tumors. In this study, we sought to develop a cervical cancer-targeted ADC using a novel molecular target. Methods: Firstly, human cervical cancer and paracancerous tissue were stained by immunohistochemistry (IHC) in order to determine the difference of the expression level of a molecular target. Three human cervical cancer cell lines (C-33A, Si-Ha and Ca-Ski) and one normal cervical cell line (HCerEpiC) were used to determine the subcellular location of an ADC target on the cells by immunofluorescence (IF) staining, flow cytometry and single photon confocal microscopy. Secondly, endocytosis capability of target antibodies was visualized by confocal imaging and was quantified by flow cytometric analysis. Furthermore, a panel of ADC formulations with different chemical linkers and payloads were designed, constructed and characterized as ADC candidates for cervical cancer therapy. We next evaluated in vitro inhibitory activity of these ADC candidates on three cervical cancer cell lines by CCK8 assay. Finally, orthotopic and lung metastasis animal models of cervical cancer were established to determine the in vivo inhibitory activity and biosafety of constructed ADC candidates. Results: IHC staining of clinical specimens showed that the expression level of CD54 in cervical tumor tissues was significantly higher than those of paracancerous tissues. Fluorescence imaging and flow cytometry further determined the overexpression level, plasma membrane location and antigen-mediated endocytosis activity of CD54 in multiple human cervical cancer cell lines. Among several ADC formulations, an optimized CD54-targeted ADC linker and warhead combination was identified by comparing its IC50 with other ADC candidates and standard-of-care chemodrugs for cervical cancer. The optimized CD54 ADC exhibited promising anti-tumor activity on primary and lung metastatic cervical tumor models. Conclusion: In our study, we identified CD54 as a novel ADC target for cervical cancer. An optimized CD54-targeted ADC formulation was determined and its anti-tumor activity and biosafety profile were determined in multiple human cervical cancer cell lines in vitro and orthotopic and lung metastatic cervical tumor models in vivo, providing a promising targeted therapeutic candidate for the targeted treatment of cervical cancer. Citation Format: Shili Yao, Bing Zhu, Xinyan Wang, Rui Xu, Tong Yang, Peng Guo, Huarong Tang, Tao Zhu. Developing a novel antibody drug conjugate against cervical cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6174.