Fig. 5

Modulation of HSP70 and MAPK signaling by circ_0000045 silencing in HNSCC cells. A, B The elevation of HSP70 and HSPA8 gene expression in HNSCC cells by circ_0000045 silencing. The expression of HSP70 (A) and HSPA8 (B) genes were determined in both FaDu and SCC-9 cells by quantitative RT-PCR. C, D Significant decrease in JNK2 and p38 gene mRNA levels in both FaDu and SCC-9 cells caused by circ_0000045 silencing. Quantitative RT-PCR was conducted to analyze JNK2 and P38 mRNA levels. E Alterations in HSP70, JNK2, and P38 protein levels in FaDu and SCC-9 cells with silenced circ_0000045 expression at 48 h. Western blotting was used to measure protein abundances in HNSCC cells. However, GAPDH was detected as the internal standard. N = 3; HSP70: heat shock 70kDa protein; HSPA8: heat shock 70kDa protein 8; NC: negative control of siRNA; JNK2: c-Jun N-terminal kinase 2; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; *P < 0.05; **P < 0.01