Halophilic Carotenoids and Breast Cancer: From Salt Marshes to Biomedicine

Abstract

Breast cancer is the leading cause of death among women worldwide. Over the years, oxidative stress has been linked to the onset and progression of cancer. In addition to the classical histological classification, breast carcinomas are classified into phenotypes according to hormone receptors (estrogen receptor—RE—/progesterone receptor—PR) and growth factor receptor (human epidermal growth factor receptor—HER2) expression. Luminal tumors (ER/PR-positive/HER2-negative) are present in older patients with a better outcome. However, patients with HER2-positive or triple-negative breast cancer (TNBC) (ER/PR/HER2-negative) subtypes still represent highly aggressive behavior, metastasis, poor prognosis, and drug resistance. Therefore, new alternative therapies have become an urgent clinical need. In recent years, anticancer agents based on natural products have been receiving huge interest. In particular, carotenoids are natural compounds present in fruits and vegetables, but algae, bacteria, and archaea also produce them. The antioxidant properties of carotenoids have been studied during the last years due to their potential in preventing and treating multiple diseases, including cancer. Although the effect of carotenoids on breast cancer during in vitro and in vivo studies is promising, clinical trials are still inconclusive. The haloarchaeal carotenoid bacterioruberin holds great promise to the future of biomedicine due to its particular structure, and antioxidant activity. However, much work remains to be performed to draw firm conclusions. This review summarizes the current knowledge on pre-clinical and clinical analysis on the use of carotenoids as chemopreventive and chemotherapeutic agents in breast cancer, highlighting the most recent results regarding the use of bacterioruberin from haloarchaea.

Identification, Antioxidant Capacity, and Matrix Metallopeptidase 9 (MMP-9) In Silico Inhibition of Haloarchaeal Carotenoids from Natronococcus sp. and Halorubrum tebenquichense

“…genera it is common to find bisanhydrobacterioruberin as the more abundant C50 carotenoid [ 13 , 40 ]. In the case of astaxanthin found in Halorubrum tebenquichense SU10, other xanthophylls were reported in Halobacterium and Haloferax species, principally canthaxanthin or haloxanthin [ 41 , 42 ].…”

Extremophiles in a changing world

“…Haloarchaeal carotenoids, in particular bacterioruberin, are especially exciting as they might represent the first case of extremolytes with a demonstrated therapeutic effect in vitro. Bacterioruberin, a rare C 50 carotenoid synthesized by most haloarchaea has been shown to exhibit the highest antioxidant capacity of all known carotenoids, including ß-carotene (Mandelli et al 2012 ), and were recently shown in in vitro studies to have a cytotoxic effect on human breast cancer lines (Giani et al 2021 , 2023 ). A novel C 50 carotenoid were also recently identified from Natrialba sp.…”

Control of Redox Homeostasis by Short-Chain Fatty Acids: Implications for the Prevention and Treatment of Breast Cancer

“…There is preclinical evidence of the preventive effects of lycopene on mouse cutaneous tumors in the promotion phase, via stimulation of NRF2 signaling pathway, and p62-mediated degradation of Keap1, via the autophagy-lysosomal pathway [ 38 ]. Recent studies have shown that the halophilic carotenoid bacterioruberin from haloarchae may have a promising future due to its particular structure and antioxidant activity [ 39 ].…”