Bacterioruberin extract from Haloferax mediterranei induces apoptosis and cell cycle arrest in myeloid leukaemia cell lines

Carotenoids, a diverse group of naturally occurring pigments, have gained attention for their potential anticancer properties. Among them, bacterioruberin (BR), a rare C50 carotenoid, has shown promising bioactivities. This study evaluates the antiproliferative and cytotoxic effects of a bacterioruberin-rich carotenoid extract (BRCE) derived from Haloferax (H.) mediterranei on myeloid leukaemia (ML) cell lines, including chronic myelogenous leukaemia (CML) and acute myelogenous leukaemia (AML) models. Using MTT assay, Annexin V/PI and AO/EtBr staining, CFDA-SE proliferation assay, PI-based cell cycle analysis, and H₂DCF-DA for reactive oxygen species (ROS) quantification, we demonstrate that BRCE significantly reduces cell viability, induces apoptosis, causes G2/M cell cycle arrest, and increases ROS levels in leukaemia cell lines. Notably, BRCE exhibited selective cytotoxicity, with minimal effects on normal PBMCs from healthy donors, suggesting its potential for tumour-specific targeting. Additionally, we analysed the morphological features of the cells treated with BRCE, observing significant changes such as cell blebbing, clumping, and the formation of apoptotic bodies, which are indicative of the induction of apoptosis. Overall, this research underscores an antitumoural therapeutic potential of BRCEs from H. mediterranei, providing a basis for future studies on their application in leukaemia treatment. Further investigation is needed to fully understand the molecular mechanisms involved and optimize BRCE for clinical use.