Epithelial Mesenchymal Transition and Progression of Breast Cancer Promoted by Diabetes Mellitus in Mice Are Associated with Increased Expression of Glycolytic and Proteolytic Enzymes.

The development of breast cancer (BC) is influenced by age, overweight, obesity, metabolic syndrome, and diabetes mellitus (DM), which are associated with hyperglycemia, glucose intolerance, insulin resistance, and oxidative stress. High glucose concentration increases a metastatic phenotype in cultured breast cancer cells, promoting cell proliferation, reactive species production (ROS), epithelial mesenchymal transition (EMT), and expression of proteolytic enzymes. Our aim was to determine whether diabetes mellitus favor BC progression in mice and its association with changes in the content of ROS and glycolytic and proteolytic enzymes. Diabetes was induced in 7-week-old Balb/c mice, under 6-h fasting with a unique i. p. dose of streptozotocin 120 mg/kg. Furthermore, 4T1 breast cancer cells were injected beneath the nipple to induce tumors. G6PD, GAPDH, ENO1, uPA, uPAR, PAI-1, ß-catenin, Snail, vimentin, and E-cadherin were measured by western blot and MPP-9 and MMP-2 by gel zymography. TBARS were measured as markers of the lipid peroxidation. Lower survival and increased tumor growth, together with marked EMT, were found in diabetic in comparison with nondiabetic mice. The effects of diabetes were associated with enhanced lipid peroxidation and higher levels of glycolytic (G6PD, GAPDH, and ENO1) and proteolytic (uPA, MMP-9) enzymes. Possibly, hyperglycemia and ROS led to faster progression of breast cancer in diabetic mice, fomenting EMT and the expression of glycolytic and proteolytic enzymes. These enzymes participate in the supply of energy and precursors for macromolecular biosynthesis and extracellular matrix degradation during breast cancer progression.

Epsilon-aminocaproic acid prevents high glucose and insulin induced-invasiveness in MDA-MB-231 breast cancer cells, modulating the plasminogen activator system.

Obesity and type II diabetes mellitus have contributed to the increase of breast cancer incidence worldwide. High glucose concentration promotes the proliferation of metastatic cells, favoring the activation of the plasminogen/plasmin system, thus contributing to tumor progression. The efficient formation of plasmin is dependent on the binding of plasminogen to the cell surface. We studied the effect of ε-aminocaproic acid (EACA), an inhibitor of the binding of plasminogen to cell surface, on proliferation, migration, invasion, epithelial-mesenchymal transition (EMT), and plasminogen activation system, in metastatic MDA-MB-231 breast cancer cells grown in a high glucose microenvironment and treated with insulin. MDA-MB-231 cells were treated with EACA 12.5 mmol/L under high glucose 30 mmol/L (HG) and high glucose and insulin 80 nmol/L (HG-I) conditions, evaluating: cell population growth, % of viability, migratory, and invasive abilities, as well as the expression of uPA, its receptor (uPAR), and its inhibitor (PAI-1), by real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, MMP-2 and MMP-9 mRNAs were evaluated by RT-PCR. Markers of EMT were evaluated by Western blot. Additionally, the presence of active uPA was studied by gel zymography, using casein-plasminogen as substrates. EACA prevented the increase in cell population, migration and invasion induced by HG and insulin, which was associated with the inhibition of EMT and the attenuation of HG- and insulin-dependent expression of uPA, uPAR, PAI-1, MMP-2, MMP-9, α-enolase (ENO A), and HCAM. The interaction of plasminogen to the cell surface and plasmin formation are mediators of the prometastasic action of hyperglycemia and insulin, potentially, EACA can be employed in the prevention and as adjuvant treatment of breast tumorigenesis promoted by hyperglycemia and insulin.