Ruriko Nakae1, Shinya Matsuzaki2, Satoshi Serada3, Koji Matsuo4, Mayu Shiomi5, Kazuaki Sato6, Yoshikazu Nagase5, Satoko Matsuzaki7, Satoshi Nakagawa5, Kosuke Hiramatsu5, Akiko Okazawa5, Toshihiro Kimura5, Tomomi Egawa-Takata8, Eiji Kobayashi5, Yutaka Ueda5, Kiyoshi Yoshino9, Tetsuji Naka10, Tadashi Kimura5. 1. Department of Obstetrics and Gynecology, Osaka University, Osaka, Japan; Department of Obstetrics and Gynecology, Sumitomo Hospital, Osaka, Japan. 2. Department of Obstetrics and Gynecology, Osaka University, Osaka, Japan; Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Southern California, Los Angeles, CA. Electronic address: zacky@gyne.med.osaka-u.ac.jp. 3. Center for Intractable Immune Disease, Kochi Medical School, Kochi University, Kochi, Japan. Electronic address: serada@kochi-u.ac.jp. 4. Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Southern California, Los Angeles, CA; Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA. 5. Department of Obstetrics and Gynecology, Osaka University, Osaka, Japan. 6. Department of Pathology, Graduate School of Medicine, Osaka University, Osaka, Japan. 7. Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Southern California, Los Angeles, CA; Department of Obstetrics and Gynecology, Otemae Hospital, Osaka, Japan. 8. Department of Obstetrics and Gynecology, Osaka Police Hospital, Osaka, Japan; Department of Obstetrics and Gynecology, Kansai Rosai Hospital, Amagasaki, Japan. 9. Department of Obstetrics and Gynecology, Osaka University, Osaka, Japan; Department of Obstetrics and Gynecology, University of Occupational and Environmental Health, Fukuoka, Japan. 10. Center for Intractable Immune Disease, Kochi Medical School, Kochi University, Kochi, Japan.
Abstract
BACKGROUND: Uterine leiomyosarcoma is a rare and aggressive gynecologic malignancy originating in the myometrium of the uterine corpus that tends to recur even after complete surgical excision. Current therapeutic agents have only modest effects on uterine leiomyosarcoma. Although antibodies and antibody-drug conjugates have been recognized as useful targeted therapies for other cancers, no study has yet evaluated the effects of this approach on uterine leiomyosarcoma. OBJECTIVE: This study aimed to examine the activity of tumoral CD70 in uterine leiomyosarcoma and assess the antitumor activity of CD70-antibody-drug conjugate treatment in uterine leiomyosarcoma. STUDY DESIGN: Target membrane proteins were screened by profiling and comparing membrane protein expression in 3 uterine leiomyosarcoma cell lines (SK-UT-1, SK-LMS-1, and SKN) and normal uterine myometrium cells using the isobaric tags for relative and absolute quantitation labeling method. Western blotting, fluorescence-activated cell sorting analyses, and immunohistochemistry were used to examine CD70 expression in the membrane proteins in uterine leiomyosarcoma cell lines and clinical samples. We developed an antibody-drug conjugate with a monoclonal antibody of the target membrane protein linked to monomethyl auristatin F and investigated its antitumor effects against uterine leiomyosarcoma (in vitro, in vivo, and in patient-derived xenograft models). RESULTS: CD70 was identified as a specific antigen highly expressed in uterine leiomyosarcoma cell lines. Of the 3 uterine leiomyosarcoma cell lines, CD70 expression was confirmed in SK-LMS-1 cells by western blotting and fluorescence-activated cell sorting analysis. CD70 overexpression was observed in 19 of 21 (90.5%) tumor specimens from women with uterine leiomyosarcoma. To generate CD70-antibody-drug conjugate, anti-CD70 monoclonal antibody was conjugated with a novel derivative of monomethyl auristatin F. CD70-antibody-drug conjugate showed significant antitumor effects on SK-LMS-1 cells (half maximal inhibitory concentration, 0.120 nM) and no antitumor effects on CD70-negative uterine leiomyosarcoma cells. CD70-antibody-drug conjugate significantly inhibited tumor growth in the SK-LMS-1 xenograft mouse model (tumor volume, 129.8 vs 285.5 mm3; relative reduction, 54.5%; P<.001) and patient-derived xenograft mouse model (tumor volume, 128.1 vs 837.7 mm3; relative reduction, 84.7%; P<.001). CONCLUSION: Uterine leiomyosarcoma tumors highly express CD70 and targeted therapy with CD70-antibody-drug conjugate may have a potential therapeutic implication in the treatment of uterine leiomyosarcoma.
BACKGROUND: Uterine leiomyosarcoma is a rare and aggressive gynecologic malignancy originating in the myometrium of the uterine corpus that tends to recur even after complete surgical excision. Current therapeutic agents have only modest effects on uterine leiomyosarcoma. Although antibodies and antibody-drug conjugates have been recognized as useful targeted therapies for other cancers, no study has yet evaluated the effects of this approach on uterine leiomyosarcoma. OBJECTIVE: This study aimed to examine the activity of tumoral CD70 in uterine leiomyosarcoma and assess the antitumor activity of CD70-antibody-drug conjugate treatment in uterine leiomyosarcoma. STUDY DESIGN: Target membrane proteins were screened by profiling and comparing membrane protein expression in 3 uterine leiomyosarcoma cell lines (SK-UT-1, SK-LMS-1, and SKN) and normal uterine myometrium cells using the isobaric tags for relative and absolute quantitation labeling method. Western blotting, fluorescence-activated cell sorting analyses, and immunohistochemistry were used to examine CD70 expression in the membrane proteins in uterine leiomyosarcoma cell lines and clinical samples. We developed an antibody-drug conjugate with a monoclonal antibody of the target membrane protein linked to monomethyl auristatin F and investigated its antitumor effects against uterine leiomyosarcoma (in vitro, in vivo, and in patient-derived xenograft models). RESULTS: CD70 was identified as a specific antigen highly expressed in uterine leiomyosarcoma cell lines. Of the 3 uterine leiomyosarcoma cell lines, CD70 expression was confirmed in SK-LMS-1 cells by western blotting and fluorescence-activated cell sorting analysis. CD70 overexpression was observed in 19 of 21 (90.5%) tumor specimens from women with uterine leiomyosarcoma. To generate CD70-antibody-drug conjugate, anti-CD70 monoclonal antibody was conjugated with a novel derivative of monomethyl auristatin F. CD70-antibody-drug conjugate showed significant antitumor effects on SK-LMS-1 cells (half maximal inhibitory concentration, 0.120 nM) and no antitumor effects on CD70-negative uterine leiomyosarcoma cells. CD70-antibody-drug conjugate significantly inhibited tumor growth in the SK-LMS-1 xenograft mouse model (tumor volume, 129.8 vs 285.5 mm3; relative reduction, 54.5%; P<.001) and patient-derived xenograft mouse model (tumor volume, 128.1 vs 837.7 mm3; relative reduction, 84.7%; P<.001). CONCLUSION: Uterine leiomyosarcoma tumors highly express CD70 and targeted therapy with CD70-antibody-drug conjugate may have a potential therapeutic implication in the treatment of uterine leiomyosarcoma.