American Association for Cancer Research
10780432ccr161326-sup-166884_2_supp_3664636_rdg7s6.pptx (166.04 kB)

Supplementary Figure S3 from Influencing the Tumor Microenvironment: A Phase II Study of Copper Depletion Using Tetrathiomolybdate in Patients with Breast Cancer at High Risk for Recurrence and in Preclinical Models of Lung Metastases

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posted on 2023-03-31, 19:42 authored by Nancy Chan, Amy Willis, Naomi Kornhauser, Maureen M. Ward, Sharrell B. Lee, Eleni Nackos, Bo Ri Seo, Ellen Chuang, Tessa Cigler, Anne Moore, Diana Donovan, Marta Vallee Cobham, Veronica Fitzpatrick, Sarah Schneider, Alysia Wiener, Jessica Guillaume-Abraham, Elnaz Aljom, Richard Zelkowitz, J. David Warren, Maureen E. Lane, Claudia Fischbach, Vivek Mittal, Linda Vahdat

The top panel shows the reaction chemistry of established lysyl oxidase (LOX) activity assay. The bottom panel shows the Amplex Red/HRP-based LOX activity assay that detects LOX activity in vitro.



Purpose: Bone marrow–derived progenitor cells, including VEGFR2+ endothelial progenitor cells (EPCs) and copper-dependent pathways, model the tumor microenvironment. We hypothesized that copper depletion using tetrathiomolybdate would reduce EPCs in high risk for patients with breast cancer who have relapsed. We investigated the effect of tetrathiomolybdate on the tumor microenvironment in preclinical models.Experimental Design: Patients with stage II triple-negative breast cancer (TNBC), stage III and stage IV without any evidence of disease (NED), received oral tetrathiomolybdate to maintain ceruloplasmin (Cp) between 8 and 17 mg/dL for 2 years or until relapse. Endpoints were effect on EPCs and other biomarkers, safety, event-free (EFS), and overall survival (OS). For laboratory studies, MDA-LM2-luciferase cells were implanted into CB17-SCID mice and treated with tetrathiomolybdate or water. Tumor progression was quantified by bioluminescence imaging (BLI), copper depletion status by Cp oxidase levels, lysyl oxidase (LOX) activity by ELISA, and collagen deposition.Results: Seventy-five patients enrolled; 51 patients completed 2 years (1,396 cycles). Most common grade 3/4 toxicity was neutropenia (3.7%). Lower Cp levels correlated with reduced EPCs (P = 0.002) and LOXL-2 (P < 0.001). Two-year EFS for patients with stage II–III and stage IV NED was 91% and 67%, respectively. For patients with TNBC, EFS was 90% (adjuvant patients) and 69% (stage IV NED patients) at a median follow-up of 6.3 years, respectively. In preclinical models, tetrathiomolybdate decreased metastases to lungs (P = 0.04), LOX activity (P = 0.03), and collagen crosslinking (P = 0.012).Conclusions: Tetrathiomolybdate is safe, well tolerated, and affects copper-dependent components of the tumor microenvironment. Biomarker-driven clinical trials in high risk for patients with recurrent breast cancer are warranted.