Investigator

Anda M. Vlad

University Of Pittsburgh

AMVAnda M. Vlad
Papers(3)
Murine cell lines wit…Quiescent Ovarian Can…Endometriosis-Associa…
Collaborators(10)
Francesmary ModugnoEster GoldfeldEsther ElishaevHuda I. AtiyaIbrahim UygunJaynish S. ShahJoan F. BrozickLan CoffmanLeonard FrisbieLixin Zhang
Institutions(3)
University Of Pittsbu…Monash UniversityMagee-Womens Hospital

Papers

Quiescent Ovarian Cancer Cells Secrete Follistatin to Induce Chemotherapy Resistance in Surrounding Cells in Response to Chemotherapy

Abstract Purpose: We recently reported that the transcription factor NFATC4, in response to chemotherapy, drives cellular quiescence to increase ovarian cancer chemoresistance. The goal of this work was to better understand the mechanisms of NFATC4-driven ovarian cancer chemoresistance. Experimental Design: We used RNA sequencing to identify NFATC4-mediated differential gene expression. CRISPR-Cas9 and FST (follistatin)-neutralizing antibodies were used to assess impact of loss of FST function on cell proliferation and chemoresistance. ELISA was used to quantify FST induction in patient samples and in vitro in response to chemotherapy. Results: We found that NFATC4 upregulates FST mRNA and protein expression predominantly in quiescent cells and FST is further upregulated following chemotherapy treatment. FST acts in at least a paracrine manner to induce a p-ATF2–dependent quiescent phenotype and chemoresistance in non-quiescent cells. Consistent with this, CRISPR knockout (KO) of FST in ovarian cancer cells or antibody-mediated neutralization of FST sensitizes ovarian cancer cells to chemotherapy treatment. Similarly, CRISPR KO of FST in tumors increased chemotherapy-mediated tumor eradication in an otherwise chemotherapy-resistant tumor model. Suggesting a role for FST in chemoresistance in patients, FST protein in the abdominal fluid of patients with ovarian cancer significantly increases within 24 hours of chemotherapy exposure. FST levels decline to baseline levels in patients no longer receiving chemotherapy with no evidence of disease. Furthermore, elevated FST expression in patient tumors is correlated with poor progression-free, post–progression-free, and overall survival. Conclusions: FST is a novel therapeutic target to improve ovarian cancer response to chemotherapy and potentially reduce recurrence rates.

Endometriosis-Associated Mesenchymal Stem Cells Support Ovarian Clear Cell Carcinoma through Iron Regulation

Abstract Ovarian clear cell carcinoma (OCCC) is a deadly and treatment-resistant cancer, which arises within the unique microenvironment of endometriosis. In this study, we identified a subset of endometriosis-derived mesenchymal stem cells (enMSC) characterized by loss of CD10 expression that specifically support OCCC growth. RNA sequencing identified alterations in iron export in CD10-negative enMSCs and reciprocal changes in metal transport in cocultured OCCC cells. CD10-negative enMSCs exhibited elevated expression of iron export proteins hephaestin and ferroportin and donate iron to associated OCCCs, functionally increasing the levels of labile intracellular iron. Iron is necessary for OCCC growth, and CD10-negative enMSCs prevented the growth inhibitory effects of iron chelation. In addition, enMSC-mediated increases in OCCC iron resulted in a unique sensitivity to ferroptosis. In vitro and in vivo, treatment with the ferroptosis inducer erastin resulted in significant death of cancer cells grown with CD10-negative enMSCs. Collectively, this work describes a novel mechanism of stromal-mediated tumor support via iron donation. This work also defines an important role of endometriosis-associated MSCs in supporting OCCC growth and identifies a critical therapeutic vulnerability of OCCC to ferroptosis based on stromal phenotype. Significance: Endometriosis-derived mesenchymal stem cells support ovarian clear cell carcinoma via iron donation necessary for cancer growth, which also confers sensitivity to ferroptosis-inducing therapy.

3Papers
25Collaborators