Iron depletion-induced downregulation of N-cadherin expression inhibits invasive malignant phenotypes in human esophageal cancer.

Esophageal carcinomas often have a poor prognosis due to early lymph node metastasis. Epithelial-mesenchymal transition (EMT) is strongly associated with the acquisition of cancer metastasis and invasion. However, there is no established treatment to eliminate the EMT of cancer cells. Iron is an essential element for both normal and cancer cells in humans. Recently, iron depletion has been discovered to suppress tumor growth. Therefore, we hypothesized that decreased iron conditions would regulate EMT phenotypes, as well as suppressing tumor growth. The human TE esophageal cancer cell lines and OE19 were used in our study. Decreased iron conditions were made using an iron-depletion diet in mice and the iron chelator deferasirox for cell studies. Migration and invasion abilities of cells were measured using migration, invasion, and sphere-formation assays. Esophageal subcutaneous tumor growth was suppressed in decreased iron conditions. In vitro study showed that decreased iron conditions inhibited esophageal cancer cell proliferation as well as migration and invasion abilities, with downregulation of N-cadherin expression. Also, migration and invasion abilities were suppressed by inhibiting expression of N-cadherin. In conclusion, decreased iron conditions revealed a profound anticancer effect by the suppression of tumor growth and the inhibition of migration and invasion abilities via N-cadherin.

A novel synergistic effect of iron depletion on antiangiogenic cancer therapy.

Iron is an essential element for both normal and cancer cells in humans. Treatment to reduce iron levels has been shown to suppress tumor growth in vivo. However, iron depletion monotherapy by iron decreased treatment has not been thought to be superior to ordinary chemotherapy and is not part of the standard therapeutic strategy for the treatment of cancer. Iron depletion is also known to reduce serum hemoglobin and oxygen supply to the tissue, which indicates that iron depletion may induce angiogenesis. Therefore, we hypothesized that iron depletion with antiangiogenic therapy can have a novel therapeutic effect in the treatment of cancer. Human nonsmall cell carcinoma cell lines A549 and H1299 were used in our study. An iron-deficient diet and an iron chelator were used to simulate an iron-depleted condition. The antitumor effects of iron depletion and antiangiogenic therapy were determined on A549 xenograft mice. The iron-depleted condition produced by an iron-deficient diet suppressed tumor growth. Tumor tissue from the iron-deficient diet group showed that cancer cell proliferation was suppressed and hypoxia was induced. Microvessel density of this group was increased which suggested that the iron-depleted condition induced angiogenesis. Bevacizumab administration had a synergetic effect on inhibiting the tumor growth on Day 39. An iron-depleted condition inhibited cancer cell proliferation and reciprocally induced angiogenesis. Bevacizumab synergistically enhanced the iron-depleted antitumor effect. Treatment to deplete iron levels combined with anti-angiogenic therapy could induce a novel therapeutic effect in the treatment of cancer.