Betula etnensis Raf. (Betulaceae) Extract Induced HO-1 Expression and Ferroptosis Cell Death in Human Colon Cancer Cells.

Giuseppe Antonio Malfa,Marcella Renis,Francesco Paolo Cammarata,Monica Ragusa,Alfonsina La Mantia,Carlo Genovese,Claudia Di Giacomo,Barbara Tomasello,Rosaria Acquaviva

doi:10.3390/ijms20112723

Abstract

Betula etnensis Raf. (Birch Etna) belonging to the Betulaceae family grows on the eastern slope of Etna. Many bioactive compounds present in Betula species are considered promising anticancer agents. In this study, we evaluated the effects of B. etnensis Raf. bark methanolic extract on a human colon cancer cell line (CaCo2). In order to elucidate the mechanisms of action of the extract, cellular redox status, cell cycle, and heme oxygenase-1 (HO-1) expression in ferroptosis induction were evaluated. Cell viability and proliferation were tested by tetrazolium (MTT) assayand cell cycle analysis, while cell death was evaluated by annexin V test and lactic dehydrogenase (LDH) release. Cellular redox status was assessed by measuring thiol groups (RSH) content, reactive oxygen species (ROS) production, lipid hydroperoxide (LOOH) levels and (γ-glutamylcysteine synthetase) γ-GCS and HO-1 expressions. The extract significantly reduced cell viability of CaCo2, inducing necrotic cell death in a concentration-depending manner. In addition, an increase in ROS levels and a decrease of RSH content without modulation in γ-GCS expression were detected, with an augmentation in LOOH levels and drastic increase in HO-1 expression. These results suggest that the B. etnensis Raf. extract promotes an oxidative cellular microenvironment resulting in CaCo2 cell death by ferroptosis mediated by HO-1 hyper-expression.

Highlights

After prostate cancer in men, breast cancer in women and lung cancer, the colorectal cancer (CRC) represents the second leading cause of death in the Western world in both males and females
Cell Cycle AWnhaelynsiCsaCo2 cells were treated with increasing concentrations of B. etnensis Raf. for 72 h, a dose W2.h8.edCneeCpllaeCCnydoce2lenctAeclnlesalllwycseyirsceletraearrteesdt watitGh0i/nGcr1eaansidngS cpohnacseenstrwateiroenesvoifdBen. ettwneinthsiscoRnacf.omfoirta7n2thm, aardkoesde decrease dependenitnctehllecGyc2l/eMarprehsatsaet
CRC is the most responsive to dietary modification, several studies demonstrated that approximatively 75% of all sporadic cases of CRC are directly influenced by diet and that dietary modification is a feasible strategy for reducing CRC risk [5,15,16]

Summary

Introduction

After prostate cancer in men, breast cancer in women and lung cancer, the colorectal cancer (CRC) represents the second leading cause of death in the Western world in both males and females. Natural antioxidants are known to have a dual face, behaving as pro-oxidant compounds after reacting directly with reactive oxygen species (ROS) in the presence of transition metal ions, such as copper and iron. This increase of cellular ROS to cytotoxic level may generate secondary oxidative damage and induce a selective killing of cancer cells by a variety of ways including ferroptosis, a non-apoptotic form of cell death characterized by the high expression of heme oxygenase-1 (HO-1) and accumulation of lipid hydroperoxides (LOOH) [8]. HO-1 has been described as survival molecule because of its anti-apoptotic and pro-angiogenic effects in several cancer types and its modulation can be induced by several natural compounds such as polyphenols and terpenoids [5]

Methods

Results

Discussion

Conclusion