HSPA5 and glioblastoma: To further analyze whether the high expression of GRP78 renders GBM cells resistant to TAK-243, we downregulated GRP78 expression in U87 and LN229 cells, which had high GRP78 expression, and over-expressed GRP78 in U251 cells, which had a low level of GRP78 expression (Supplemental Fig. S4).