Sarah T K Sin1, Yan Li2, Ming Liu3, Stephanie Ma4, Xin-Yuan Guan5. 1. Department of Clinical Oncology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong. 2. Department of Biology, Southern University of Science and Technology of China, Shenzhen, China. 3. School of Basic Sciences, Guangzhou Medical University, Guangzhou, China. 4. School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong. 5. Department of Clinical Oncology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong; State Key Laboratory of Oncology in South China, Sun Yat-Sen University Cancer Center, Guangzhou, China. Electronic address: xyguan@hku.hk.
Abstract
OBJECTIVE: Inactivation of tumor suppressor genes promotes initiation and progression of cervical cancer. This study aims to investigate the tumor suppressive effects of TROP-2 in cervical cancer cells and to explain the underlying mechanisms. METHODS: The tumor suppressive functions of TROP-2 in cervical cancer cells were examined by in vitro and in vivo tumorigenic functional assays. Downstream factors of TROP-2 were screened using Human Phospho-Receptor Tyrosine Kinase Array. Small molecule inhibitors were applied to HeLa cells to test the TROP-2 effects on the oncogenicity of IGF-1R and ALK. Protein interactions between TROP-2 and the ligands of IGF-1R and ALK were detected via immunoprecipitation assay and protein-protein affinity prediction. RESULTS: In vitro and in vivo functional assays showed that overexpression of TROP-2 significantly inhibited the oncogenicity of cervical cancer cells; while knockdown of TROP-2 exhibited opposite effects. Human Phospho-Receptor Tyrosine Kinase Array showed that the activity of IGF-1R and ALK was stimulated by TROP-2 knockdown. Small molecule inhibitors AG1024 targeting IGF-1R and Crizotinib targeting ALK were treated to HeLa cells with and without TROP-2 overexpression, and results from cell viability and migration assays indicated that the oncogenicity of vector-transfected cells was repressed to a greater extent by the inhibition of either IGF-1R or ALK than that of the TROP-2-overexpressed cells. Immunoprecipitation assay and protein-protein affinity prediction suggested protein interactions between TROP-2 and the ligands of IGF-1R and ALK. CONCLUSIONS: Collectively, our results support that TROP-2 exhibits tumor suppressor functions in cervical cancer through inhibiting the activity of IGF-1R and ALK.
OBJECTIVE: Inactivation of tumor suppressor genes promotes initiation and progression of cervical cancer. This study aims to investigate the tumor suppressive effects of TROP-2 in cervical cancer cells and to explain the underlying mechanisms. METHODS: The tumor suppressive functions of TROP-2 in cervical cancer cells were examined by in vitro and in vivo tumorigenic functional assays. Downstream factors of TROP-2 were screened using Human Phospho-Receptor Tyrosine Kinase Array. Small molecule inhibitors were applied to HeLa cells to test the TROP-2 effects on the oncogenicity of IGF-1R and ALK. Protein interactions between TROP-2 and the ligands of IGF-1R and ALK were detected via immunoprecipitation assay and protein-protein affinity prediction. RESULTS: In vitro and in vivo functional assays showed that overexpression of TROP-2 significantly inhibited the oncogenicity of cervical cancer cells; while knockdown of TROP-2 exhibited opposite effects. Human Phospho-Receptor Tyrosine Kinase Array showed that the activity of IGF-1R and ALK was stimulated by TROP-2 knockdown. Small molecule inhibitors AG1024 targeting IGF-1R and Crizotinib targeting ALK were treated to HeLa cells with and without TROP-2 overexpression, and results from cell viability and migration assays indicated that the oncogenicity of vector-transfected cells was repressed to a greater extent by the inhibition of either IGF-1R or ALK than that of the TROP-2-overexpressed cells. Immunoprecipitation assay and protein-protein affinity prediction suggested protein interactions between TROP-2 and the ligands of IGF-1R and ALK. CONCLUSIONS: Collectively, our results support that TROP-2 exhibits tumor suppressor functions in cervical cancer through inhibiting the activity of IGF-1R and ALK.