Fig. 3
From: Targeting the tumor microenvironment in B-cell lymphoma: challenges and opportunities
Impact of hypoxic TME and targeted therapy. Growth factors regulate HIF-1α through MAPK/ERK and PI3K/AKT/mTOR pathway, consequently induce the simulation of HIF-1α mRNA transactivation. Under the hypoxic microenvironment, HIF-1α in cells up-regulates the expression of PD-L1 in hypoxic tumor cells, prevents MDSC from maturation at the tumor site and involves the up-regulation of CD47 on the surface of tumor cells. After CD47 combines with SIRPα on the surface of macrophages, tumor cells provide a robust “don't phagocytize me” signal, thus preventing the phagocytosis of macrophages