Figure 3.

Trp depletion upregulates WARS expression.

(A) WARS mRNA expression measured by qRT-PCR in A172 glioblastoma cells, which exhibit constitutive TDO2 activity, cultured for 120 h in normal DMEM or with additional supplementation of 78 µM Trp after 72 h. (B) WARS2 mRNA expression measured by qRT-PCR in A172 glioblastoma cells under the conditions described in (A). (C) WARS mRNA expression measured by qRT-PCR in glioblastoma (A172, LN18, LN229) and ovarian carcinoma cells (SKOV-3) after 24 h of cultivation in medium containing 78 µM versus no Trp. (D) WARS protein levels in LN229 glioblastoma cells detected by Western blot after 48 h or 72 h of cultivation in medium containing 78 µM or no Trp. GAPDH served as loading control (E) WARS2 mRNA expression measured by qRT-PCR was not altered by the conditions described in (C). (F) WARS protein levels in the cytoplasmic or nuclear fraction of LN229 glioblastoma cells detected by Western blot after 48 h of cultivation in medium containing 78 µM or no Trp. GAPDH served as loading control for the cytoplasmic fraction, lamin A/C as loading control for the nuclear fraction. (G) WARS protein concentrations measured by ELISA in the supernatants of LN229 and A172 glioblastoma cells cultured for 48 h in the presence or absence of Trp. All data are expressed as mean ± s.e.m. Statistical significance is assumed at P < 0.05 (*P < 0.05, **P < 0.01, ***P <0.001).