DDIT3 and neuroblastoma: Consistent with this mechanism, increased levels of GRP78, ATF4 and P-eIF2α (Figure 2A), as well as a not statistically significant up-regulation of CHOP and TRB3 mRNA (Figure 2B), were detected in neuroblastoma cells following cinacalcet exposure in a time-, dose-, calcium- and CaSR-dependent manner (Supplementary Figure S2A and S2B).