In vivo inhibition of tumor progression by 5 hydroxy-1,4-naphthoquinone (juglone) and 2-(4-hydroxyanilino)-1,4-naphthoquinone (Q7) in combination with ascorbate

Abstract

The purpose of the study was to obtain further in vivo data of antitumor effects and mechanisms triggered by juglone and Q7 in combination with ascorbate. The study was done using Ehrlich ascites tumor-bearing mice. Treatments were intraperitoneal every 24 h for 9 days. Control group was treated with excipient. Previous tests selected the doses of juglone and Q7 plus ascorbate (1 and 100 mg/kg, respectively). Samples of ascitic fluid were collected to evaluate carbonyl proteins, GSH and activity of antioxidant enzymes such as catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase. Hypoxia inducible factor HIF-1α, GLUT1, proteins driving cell cycle (p53, p16 and cyclin A) and apoptosis (poly-ADP-polymerase PARP, Bax and Bcl-xL) were assessed by western blot. Tumor cells were categorized by the phase of cell cycle using flow cytometry and type of cell death using acridine orange/ethidium bromide. A glucose uptake assessment was performed by liquid scintillation using Ehrlich tumor cells cultured with (14)C-deoxyglucose. Treatments caused increased protein carbonylation and activity of antioxidant enzymes and decreased levels of GSH, HIF-1α, GLUT1 and glucose uptake in tumor cells. They also caused increased number of tumor cells in G1, p53 and p16 activation and decreased cyclin A, but only when combined with ascorbate. Apoptosis was induced mostly when treatments were done with ascorbate, causing PARP and Bax cleavage, and increased Bax/Bcl-xL ratio. Juglone and Q7 in combination with ascorbate caused inhibition of tumor progress in vivo by triggering apoptosis and cell cycle arrest associated with oxidative stress, suppression of HIF-1 and uncoupling of glycolytic metabolism.

IL-1β induced HIF-1α inhibits the differentiation of human FOXP3+ T cells

“…Notably, enhanced glycolysis or FAO inhibition prevents murine iTreg differentiation 10, 27, 47 . The inhibition of glycolysis, for example by using 2-Deoxy-D-Glucose (2-DG), promotes iTreg polarization by regulating mTOR activity 47 , which could be linked to its downregulation of HIF-1α expression, as described in tumor cell lines 48, 49 . As previous studies described HIF-1α as an important regulator of cell metabolism 10, 18, 50 , we thus analyzed the effect of IL-1β and DMOG on Treg metabolism.…”

Modulatory Effect of 2‐(4‐Hydroxyphenyl)amino‐1,4‐naphthoquinone on Endothelial Vasodilation in Rat Aorta

“…Free radicals can attack DNA at C4 of deoxyribose generating products as propenal, which react with 2-thiobarbituric acid and produce the TBARS formation [ 40 ]. In both T24 and MCF-7 cells, we found that Q7 provoked elevated levels of intracellular ROS [ 23 , 25 , 35 , 39 ].…”

“…This inhibition induced cancer cells senescence [ 10 ], reduction of DNA damage, and inhibition of in vivo tumor growth [ 11 ]. It also leads to an inhibition of in vivo tumor progression by triggering apoptosis, cell cycle arrest, suppression of HIF-1, and uncoupling glycolytic metabolism [ 25 ]. All these effects have been attributed to its ability to generate ROS through quinone redox-cycling.…”

Natural Products to Fight Cancer: A Focus on Juglans regia

“…Juglone demonstrated antitumour efficacy in in vivo models of prostate, intestinal, and Ehrlich ascites carcinoma [ 106 , 115 , 179 , 180 , 181 ]. Juglone 200 ppm was fed to weanling F344 male rats concurrently with the induced initiation phase of carcinogenesis.…”

“…Ascorbate potentiated juglone-mediated cell-cycle arrest and apoptosis, increasing the number of cells in G1 and the expression of cell-cycle inhibitors like p53 and p16. Furthermore, only in the presence of ascorbate, juglone was able to reduce the expression of cyclin A. Apoptosis-wise, the presence of ascorbate made possible to detect cleaved PARP, and increased the Bax/Bcl2 ratio [ 181 ].…”