E‐cadherin, a central component of the adherens junction (AJ), is a single‐pass transmembrane protein that mediates cell–cell adhesion. The loss of E‐cadherin surface expression, and therefore cell–cell adhesion, leads to increased cell migration and invasion. Treatment of colorectal cancer (CRC)‐derived cells (SW‐480 and HT‐29) with 2.0 mM metformin promoted a redistribution of cytosolic E‐cadherin to de novo formed puncta along the length of the contacting membranes of these cells. Metformin also promoted translocation from the cytosol to the plasma membrane of p120‐catenin, another core component of the AJs. Furthermore, E‐cadherin and p120‐catenin colocalized with β‐catenin at cell–cell contacts. Western blot analysis of lysates of CRC‐derived cells revealed a substantial metformin‐induced increase in the level of p120‐catenin as well as E‐cadherin phosphorylation on Ser838/840, a modification associated with β‐catenin/E‐cadherin interaction. These modifications in E‐cadherin, p120‐catenin and β‐catenin localization suggest that metformin induces rebuilding of AJs in CRC‐derived cells. Those modifications were accompanied by the inhibition of focal adhesion kinase (FAK), as revealed by a significant decrease in the phosphorylation of FAK at Tyr397 and paxillin at Tyr118. These changes were associated with a reduction in the numbers, but an increase in the size, of focal adhesions and by the inhibition of cell migration. Overall, these observations indicate that metformin targets multiple pathways associated with CRC development and progression.

Fibronectin (Fn) enhances human sperm capacitation via the cAMP/PKA pathway, and the endocannabinoid system participates in this process. Moreover, Fn has been linked to endocannabinoid system components in different cellular models, even though no evidence of such interactions in human sperm is available. Normal semen samples were evaluated over a 4‐year period. Our findings suggest that (a) the capacitating effects of Fn were reversed by preincubating the sperm with a cannabinoid receptor 1 (CB1) or transient receptor potential cation channel subfamily V member 1 (TRPV1) antagonist ( p < 0.001 and p < 0.05, respectively); (b) cooperation between CB1 and TRPV1 may exist ( p < 0.01); (c) the activity of specific fatty acid amide hydroxylase (FAAH) decreased after 1 min ( p < 0.01) and increased after 60 min ( p < 0.01) of capacitation in the presence of Fn; (d) the effects of Fn on FAAH activity were prevented by preincubating spermatozoa with a protein kinase A (PKA) inhibitor ( p < 0.01); (e) Fn modulated both the cyclic adenosine monophosphate concentration and PKA activity ( p < 0.05) during early capacitation; and (f) FAAH was a PKA substrate modulated by phosphorylation. These findings indicate that Fn stimulates human sperm capacitation via the cAMP/PKA pathway through modulation of the endocannabinoid system. Understanding the functional competence of human spermatozoa is essential for facilitating clinical advances in infertility treatment and for developing novel contraceptive strategies.