Adipose cells could favor breast cancer invasion by inducing the loss of the tumor-suppressor profile of mammary myoepithelial cells

Session: Progression et résistance tumorale, thérapies innovantesObesity is responsible for higher recurrence and mortality breast cancer (BC) rates. Of all the cell types present in the breast, myoepithelial cells (MyoEpCs) are considered "tumor suppressors". During the transition from in situ to invasive ductal BC, a disorganization of MyoEpCs is observed that promotes the ability of cancer cells to migrate. As the adipose microenvironment could promote BC, we would like to characterize its role on the functionality of MyoEpCs in an obese context.For this purpose, MyoEpCs (Hs 578Bst) were co-cultured with human adipose stem cells (hASC) (hMAD cell line and hASCs from healthy women). We found that the viability of MyoEpCs was reduced in the presence of hASC (-23%, -10% with hMAD and hASC respectively, p<0.05) associated with a slight increase in apoptosis. When hASC were differentiated into mature adipocytes (MA), the same impact on viability was observed (-11%, p<0.01). The influence of obesity was evaluated using hASC from thin or obese patients (hASC20, hASC30) differentiated into MA (MA20, MA30). Cells of obese women had slightly less activity on MyoEpCs viability (-13% with hASC20; -8% with hASC30; -16% with MA20, p