Masafumi Iida1,2, Kouki Tsuboi3, Toshifumi Niwa3, Takanori Ishida4, Shin-Ichi Hayashi3. 1. Department of Molecular and Functional Dynamics, Graduate School of Medicine, Tohoku University, 2-1, Seiryoumachi, Aoba-ku, Sendai, 980-8575, Japan. m.iida@med.tohoku.ac.jp. 2. Department of Breast and Endocrine Surgical Oncology, Graduate School of Medicine, Tohoku University, Sendai, Japan. m.iida@med.tohoku.ac.jp. 3. Department of Molecular and Functional Dynamics, Graduate School of Medicine, Tohoku University, 2-1, Seiryoumachi, Aoba-ku, Sendai, 980-8575, Japan. 4. Department of Breast and Endocrine Surgical Oncology, Graduate School of Medicine, Tohoku University, Sendai, Japan.
Abstract
BACKGROUND: Hormone therapy targeting the estrogen receptor (ER) pathway is the most common treatment used for ER-positive breast cancer. However, some patients experience de novo or acquired resistance, which becomes a critical problem. Activation of the insulin-like growth factor (IGF) pathway allows breast cancer cells to proliferate and is associated with the ER pathway. Little is known about the role of the IGF pathway in hormone therapy and resistance; therefore, we investigated whether the inhibition of this pathway may represent a novel therapeutic target for overcoming hormone therapy resistance in ER-positive breast cancers. METHODS: Crosstalk between the ER and IGF pathways was analyzed in breast cancer cell lines by inhibiting or stimulating either one or both pathways. We studied the effect of insulin-like growth factor one receptor (IGF1R) inhibition in aromatase inhibitor-resistant breast cancer cell lines and fulvestrant-resistant cell lines which were uniquely established in our laboratory. RESULTS: Under normal conditions, IGF signaling is controlled by ER signaling to promote cell growth. Temporary disruption of the estrogen supply results in attenuated ER signaling, and IGF-1 dramatically increased relative growth compared with normal conditions. In addition, IGF1R inhibitor strongly suppressd cell growth in hormone-resistant breast cancer cells where ER remains than cells where ER decreased or was almost lost. CONCLUSIONS: Our study suggests that inhibition of the IGF pathway may be an effective strategy for ER-positive breast cancer therapy, even in hormone therapy-resistant cases.
BACKGROUND: Hormone therapy targeting the estrogen receptor (ER) pathway is the most common treatment used for ER-positive breast cancer. However, some patients experience de novo or acquired resistance, which becomes a critical problem. Activation of the insulin-like growth factor (IGF) pathway allows breast cancer cells to proliferate and is associated with the ER pathway. Little is known about the role of the IGF pathway in hormone therapy and resistance; therefore, we investigated whether the inhibition of this pathway may represent a novel therapeutic target for overcoming hormone therapy resistance in ER-positive breast cancers. METHODS: Crosstalk between the ER and IGF pathways was analyzed in breast cancer cell lines by inhibiting or stimulating either one or both pathways. We studied the effect of insulin-like growth factor one receptor (IGF1R) inhibition in aromatase inhibitor-resistant breast cancer cell lines and fulvestrant-resistant cell lines which were uniquely established in our laboratory. RESULTS: Under normal conditions, IGF signaling is controlled by ER signaling to promote cell growth. Temporary disruption of the estrogen supply results in attenuated ER signaling, and IGF-1 dramatically increased relative growth compared with normal conditions. In addition, IGF1R inhibitor strongly suppressd cell growth in hormone-resistant breast cancer cells where ER remains than cells where ER decreased or was almost lost. CONCLUSIONS: Our study suggests that inhibition of the IGF pathway may be an effective strategy for ER-positive breast cancer therapy, even in hormone therapy-resistant cases.
Authors: Tone Hoel Lende; Marie Austdal; Anne Elin Varhaugvik; Ivar Skaland; Einar Gudlaugsson; Jan Terje Kvaløy; Lars A Akslen; Håvard Søiland; Emiel A M Janssen; Jan P A Baak Journal: BMC Cancer Date: 2019-11-08 Impact factor: 4.430
Authors: Christopher Godina; Somayeh Khazaei; Helga Tryggvadottir; Edward Visse; Björn Nodin; Karin Jirström; Signe Borgquist; Ana Bosch; Karolin Isaksson; Helena Jernström Journal: Carcinogenesis Date: 2021-11-12 Impact factor: 4.944