Fig. 6: HECTD3 mediated IR resistance through p62.

A HECTD3 KO-impaired pCHK1 (S345) was reversed by p62 knockdown. HECTD3 (Con), HECTD3 (KO) and p62 knockdown/HECTD3 KO HCC1806 and HCC1937 cells were irradiated with 10 Gy. CHK1 and pCHK1 were detected by WB. B p62 knockdown restored IR resistance in HECTD3 KO HCC1806 and HCC1937 cells. Apoptosis were analyzed by flow cytometry after annexin V/PI staining at 72 h post-IR. Data are mean ± SD. Statistical analysis was performed using two-tailed unpaired t-tests. Data are representative of three independent experiments. *p < 0.05 and **p < 0.01; ns, not significant. C p62 knockdown decreased the accumulation of \({\rm{\gamma }}\)H2AX and PARP cleavage in HECTD3 KO HCC1806 and HCC1937 cells. Cells were treated with IR (10 Gy) and harvested for WB at 72 h post-IR. D p62 knockdown restored IR resistance in HECTD3 KO HCC1806 and HCC1937 cells. Clonogenic formation of HCC1806 and HCC1937 cells in response to IR were measured. Data are mean ± SD. Statistical analysis was performed using two-tailed unpaired t-tests. Data are representative of three independent experiments. *p < 0.05 and n.s, not significant. E Schematic diagram of radiotherapy process for HECTD3 Con, HECTD3 KO and HECTD3 KO/p62 KD tumors. F–I HECTD3 KO increased the efficacy of radiotherapy and p62 KD rescues HECTD3 KO mediated IR sensitivity. Mice with HECTD3 Con, HECTD3 KO and HECTD3 KO/p62 KD tumors were divided into two groups, control or radiotherapy (n = 4 per group). 21 days post five times radiotherapy (4 Gy/time), the mice were euthanized. The image of tumors was shown (F); the tumor weight (G) and TUNEL positive ratio (H–I) were recorded. Data are mean ± SD. Statistical analysis was performed using two-tailed unpaired t-tests. *p < 0.05 and ns, not significant. Scale bar, 100 μm. J The working model of this study.