Iron Induces Cell Death and Strengthens the Efficacy of Antiandrogen Therapy in Prostate Cancer Models.

Abstract

PURPOSE:

In search of novel strategies to improve the outcome of advanced prostate cancer, we considered that prostate cancer cells rearrange iron homeostasis, favoring iron uptake and proliferation. We exploited this adaptation by exposing prostate cancer preclinical models to high-dose iron to induce toxicity and disrupt adaptation to androgen starvation.

EXPERIMENTAL DESIGN:

We analyzed markers of cell viability and mechanisms underlying iron toxicity in androgen receptor-positive VCaP and LNCaP, castration-resistant DU-145 and PC-3, and murine TRAMP-C2 cells treated with iron and/or the antiandrogen bicalutamide. We validated the results in vivo in VCaP and PC-3 xenografts and in TRAMP-C2 injected mice treated with iron and/or bicalutamide.

RESULTS:

Iron was toxic for all prostate cancer cells. In particular, VCaP, LNCaP, and TRAMP-C2 were highly iron sensitive. Toxicity was mediated by oxidative stress, which primarily affected lipids, promoting ferroptosis. In highly sensitive cells, iron additionally caused protein damage. High-basal iron content and oxidative status defined high iron sensitivity. Bicalutamide-iron combination exacerbated oxidative damage and cell death, triggering protein oxidation also in poorly iron-sensitive DU-145 and PC-3 cells.In vivo, iron reduced tumor growth in TRAMP-C2 and VCaP mice. In PC-3 xenografts, bicalutamide-iron combination caused protein oxidation and successfully impaired tumor expansion while single compounds were ineffective. Macrophages influenced body iron distribution but did not limit the iron effect on tumor expansion.

CONCLUSIONS:

Our models allow us to dissect the direct iron effect on cancer cells. We demonstrate the proof of principle that iron toxicity inhibits prostate cancer cell proliferation, proposing a novel tool to strengthen antiandrogen treatment efficacy.

• Authors: Jessica Bordini, Federica Morisi, Angela Rita Elia, Paolo Santambrogio, Alessia Pagani, Vito Cucchiara, Paolo Ghia, Matteo Bellone, Alberto Briganti, Clara Camaschella, Alessandro Campanella
• Journal: Clinical cancer research : an official journal of the American Association for Cancer Research (Clin Cancer Res) Vol. 26 Issue 23 Pg. 6387-6398 (12 01 2020) ISSN: 1557-3265 [Electronic] United States
• PMID: 32928793 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: ©2020 American Association for Cancer Research.

Chemical References

• Androgen Antagonists
• Anilides
• Nitriles
• Tosyl Compounds
• bicalutamide
• Iron

Topics

• Androgen Antagonists (pharmacology)
• Anilides (pharmacology)
• Animals
• Apoptosis
• Cell Proliferation
• Drug Synergism
• Humans
• Iron (pharmacology)
• Male
• Mice
• Nitriles (pharmacology)
• Prostatic Neoplasms (drug therapy, pathology)
• Tosyl Compounds (pharmacology)
• Tumor Cells, Cultured
• Xenograft Model Antitumor Assays