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Vasculogenic mimicry (VM) is the formation of a blood supply system that confers aggressive and metastatic properties to tumors and correlates with a poor prognosis in cancer patients. Thus, the inhibition of VM is considered an effective approach for cancer treatment, although such a mechanism remains poorly described. In the present study, we examined methionine aminopeptidase‑2 (MetAP2), a key factor of angiogenesis, and demonstrated that it is pivotal for VM, using pharmacological and genetic approaches. Fumagillin and TNP‑470, angiogenesis inhibitors that target MetAP2, significantly suppressed VM in various human cancer cell lines. We established MetAP2‑knockout (KO) human fibrosarcoma HT1080 cells using the CRISPR/Cas9 system and found that VM was attenuated in these cells. Furthermore, re‑expression of wild‑type MetAP2 restored VM in the MetAP2‑KO HT1080 cells, but the substitution of D251, a conserved amino acid in MetAP2, failed to rescue the VM. Collectively, our results demonstrate that MetAP2 is critical for VM in human cancer cells and suggest fumagillin and TNP‑470 as potent VM‑suppressing agents.

Mitochondria evolved from endosymbiotic bacteria to become essential organelles of eukaryotic cells. The unique lipid composition and structure of mitochondrial membranes are critical for the proper functioning of mitochondria. However, stress responses that help maintain the mitochondrial membrane integrity are not well understood. One reason for this lack of insight is the absence of efficient tools to specifically damage mitochondrial membranes. Here, through a compound screen, we found that two bis-biguanide compounds, chlorhexidine and alexidine, modified the activity of the inner mitochondrial membrane (IMM)-resident protease OMA1 by altering the integrity of the IMM. These compounds are well-known bactericides whose mechanism of action has centered on their damage-inducing activity on bacterial membranes. We found alexidine binds to the IMM likely through the electrostatic interaction driven by the membrane potential as well as an affinity for anionic phospholipids. Electron microscopic analysis revealed that alexidine severely perturbated the cristae structure. Notably, alexidine evoked a specific transcriptional/proteostasis signature that was not induced by other typical mitochondrial stressors, highlighting the unique property of alexidine as a novel mitochondrial membrane stressor. Our findings provide a chemical-biological tool that should enable the delineation of mitochondrial stress-signaling pathways required to maintain the mitochondrial membrane homeostasis.

Ultraviolet B radiation represents 10% of the total UV radiation that reaches the Earth's surface, being the primary responsible for the biological effects related to skin cancer and photoaging. Ilex Paraguariensis A. St. Hil., known as Yerba mate (YM), is a native tree of South America whose polyphenols in its leaves are described to exhibit photochemoprotective effect and are employed in the treatment of cancer. Additionally, the polyphenols are used to prevent lipid peroxidation and reduce the UV-induced damage, which ultimately decreases the oxidative stress. Thus, the present study aimed to characterize a new YM extract, evaluate the extract cytotoxicity and develop a formulation containing YM extract to prevent UVB-induced damage in mice skin. The YM extract showed high levels of polyphenols, flavonoids, and tannins and exhibited excellent antioxidant activity. Its main components were suggested as chlorogenic acid (1.92%) and caffeic acid (0.41%). Besides, YM extract did not exhibit cytotoxicity in fibroblasts and decreased the activity of myeloperoxidase and metalloproteinase-2 after acute UVB exposure. As a result, the formulation containing the YM extract showed a potential photochemoprotective., (Copyright © 2018. Published by Elsevier B.V.)