Estradiol Augments Tumor-Induced Neutrophil Production to Promote Tumor Cell Actions in Lymphangioleiomyomatosis Models.

Lymphangioleiomyomatosis (LAM) is a rare cystic lung disease caused by smooth muscle cell-like tumors containing tuberous sclerosis (TSC) gene mutations and found almost exclusively in females. Patient studies suggest LAM progression is estrogen-dependent, an observation supported by in vivo mouse models. However, in vitro data using TSC-null cells lines demonstrate modest estradiol responses, suggesting estradiol effects in vivo may involve pathways independent of direct tumor stimulation. We previously reported tumor-dependent neutrophil expansion and promotion of TSC2-null tumor growth in an estradiol-sensitive LAM mouse model. We therefore hypothesized that estradiol stimulates tumor growth in part by promoting neutrophil production. Here we report that estradiol-enhanced lung colonization of TSC2-null cells is indeed dependent on neutrophils. We demonstrate that estradiol induces granulopoiesis via ERα in male and female bone marrow cultures. With our novel TSC2-null mouse myometrial cell line, we show that factors released from these cells drive estradiol-sensitive neutrophil production. Lastly, we analyzed single-cell RNA sequencing data from LAM patients and demonstrate the presence of tumor-activated neutrophils. Our data suggest a powerful positive feedback loop whereby estradiol and tumor factors induce neutrophil expansion, which in turn intensifies tumor growth and production of neutrophil-stimulating factors, resulting in continued TSC2-null tumor growth.