MAP30 inhibits proliferation and metastasis of bladder cancer by increasing EGR1 expression and promoting the transcriptional activation of DUSP1

The confirmed tumor-inhibitory effects of the 30 kDa Momordica anti-human immunodeficiency virus protein (MAP30) have yet to be complemented by an exploration into its mechanism of action on tumor development and metastasis. For this purpose, we delved into the intrinsic mechanism of MAP30 in bladder cancer (BC). Here, we demonstrated that MAP30 markedly suppressed the proliferation, migration, invasion, and angiogenic capabilities of human BC cells in vitro, and the tumor metastatic potential in vivo. Furthermore, our findings showed that MAP30 suppressed the functional activities of BC cells by upregulating the expression levels of early growth response 1 (EGR1). Additionally, our investigation confirmed that EGR1 and dual specificity phosphatase 1 (DUSP1) were down-expressed in BC and had been identified as closely linked to the advancement of BC. DUSP1 was transcriptionally induced by EGR1, and the expression of EGR1 was found to be positively linked with DUSP1 in human BC tissues. The knockdown of EGR1 was found to boost cell invasion, migration, proliferation, and angiogenesis via the MAPK signaling pathway, however, the overexpression of DUSP1 inhibited EGR1 knockdown-induced promotion of these functional activities in BC cells. Furthermore, MAP30 inhibited the invasion, migration, proliferation, and angiogenesis of BC cells by regulating the EGR1-DUSP1 axis. Our study yielded an exhaustive insight into the suppressive actions of MAP30 on BC progression.