lncRNA BANCR promotes the colorectal cancer metastasis through accelerating exosomes-mediated M2 macrophage polarization via regulating RhoA/ROCK signaling.

Cancer cells-derived exosomal lncRNAs could modulate the tumorigenesis of colorectal cancer (CRC) via modulating macrophage M2 polarization. However, the clarified mechanism and function of lncRNA BANCR in CRC remains unclear. Exosomes were identified by TEM, NTA, western blot and fluorescent staining. M2 macrophages were identified by CD206 and CD163 expressions using by flow cytometry and RT-qPCR. In addition, the relation between IGF2BP2 and BANCR or RhoA were explored by RIP assay. The malignant behaviors of CRC cells were examined by CCK-8, EdU and transwell assays. Histopathological changes in mice were observed by H&E staining. Silencing of BANCR notably inhibited the proliferation, migration and invasion of CRC cells. SW620 and HCT-15 cells-derived exosomal BANCR positively regulated the macrophage M2 polarization. In addition, exosomal BANCR remarkably enhanced the promoting roles mediated by M2 macrophages on proliferation and invasion in CRC cells. Meanwhile, exosomal BANCR promoted the M2 macrophage polarization via activation of RhoA/Rock pathway by recruiting IGF2BP2. Inhibition of RhoA/Rock pathway reversed exosomal BANCR-mediated macrophages M2 polarization and CRC malignant behaviors in SW620 and HCT-15 cells. Exosomal lncRNA BANCR derived from SW620 and HCT-15 cells promoted the metastasis of CRC via inducing the polarization of M2 macrophages. Thus, BANCR might be a new target for the treatment of CRC.