ERN1 and glioblastoma: In the context of ERN1 knocked-down glioblastoma cell lines, the proliferation is markedly reduced in an environment without glutamine and glucose, an aspect that seems to be directly correlated with a change in expression of ERN1-dependent genes, such as endothelin-1 (EDN1, downregulated), its receptors A and B (EDNRA, downregulated, and EDNRB, upregulated), and the endothelin converting enzyme (ECE1, upregulated, although more markedly in control cells than in ERN1 knocked-down cells) [56].