RAC2 regulates cell adhesion in MCL. (A) JeKo-1 cells. Left: RAC2 siRNA effectively reduced RAC2 protein level compared with control siRNA. Right: cell adhesion to NKTert cells was significantly compromised. Cells were cocultured with NKTert and allowed to adhere for 24 hours before washing. Error bar represents mean ± SEM of 6 replicate reactions. (B) Same experiment as in panel A with Mino cells. (C) JeKo-1 cells. Left: exogenous expression of His-tagged RAC2 in JeKo-1 cells. Immunoblots for RAC2 and His-tag are shown. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was included as the loading control. Right: exogenous RAC2 reversed ibrutinib-induced cell adhesion impairment. (D) Same experiment as in panel A with Mino cells. Error bar represents mean ± SEM of 6 replicate reactions. (E) RAC2 single-guide RNAs (sgRNAs) effectively reduced RAC2 protein levels in Granta-519 cells compared with control cells. (F) Representative fluorescent microscopic photos showing that RAC2 knockout significantly compromised adhesion of Granta-519 cells (green) to tdTomato-BMF cells (red). **P < .01; ***P < .001.