The Triangle: Carotenoids–Retinoids–Cytochromes Govern Essential Functions for Development and Progression of Cancer

In this review, we demonstrate that the carotenoids–retinoids–cytochromes c triangle is an important cancer factor controlling most aspects of the development, proliferation, and progression of cancer. Cancer is a multidimensional disease that needs a balance between the enzymes controlling the amount of carotenoids, the production of retinoids (particularly retinoic acid), and the concentration of cytochromes (particularly cytochrome c). The proper balance between these enzymes will help in overcoming the bottleneck in cancer therapeutics using drugs. First, we discuss the impact of carotenoids on cancer. In the next section, we show how carotenoid cleavage products, including retinal, retinol, and retinoic acid, induce positive and negative effects on cancer development. Then, we discuss the impact of cytochrome c on cancer. We have demonstrated that an alteration in the cellular redox status of cytochrome c is a crucial factor in cancer, influencing numerous aspects of malignant progression. The results obtained by Raman imaging showed significant differences between normal and cancerous human cells. First, a significant redox imbalance in the hem group of cytochrome c with the upregulation of the reduced form of hem is observed. Cancer tissue has a higher concentration of reduced cytochrome c than normal tissue. Secondly, both breast and brain tumors exhibit enhanced de novo lipogenesis in comparison to normal cells. Third, this research illustrates the essential function of the extracellular matrix in oxidative phosphorylation and apoptosis pathways.