HKDC1 promotes autophagy and proliferation in pancreatic adenocarcinoma through interaction with PARP1 and poly(ADP-ribosyl)ation

Abstract

Background

HKDC1 has been shown to play an important role in promoting malignant progression of pancreatic adenocarcinoma (PAAD), but the exact mechanism is unclear. This study aimed to investigate the function of HKDC1 in autophagy activation and cell proliferation.

Methods

By GSEA analysis of TCGA data of PAAD, we found that HKDC1 was closely associated with autophagy. We evaluated the effects of HKDC1 knockdown and overexpression on the expression of LC3B, an autophagy marker, and Cyclin D1 and PCNA, cell proliferation-associated proteins, by Western blotting (WB) and transmission electron microscopy (TEM) analysis.

Results

Knockdown of HKDC1 decreased LC3B expression and led to a decrease in the accumulation of autophagic vesicles and autophagic lysosomes, while overexpression of HKDC1 produced the opposite effect. Meanwhile, HKDC1 overexpression significantly promoted the proliferation of PAAD cells and increased the expression levels of Cyclin D1 and PCNA. Further studies showed that HKDC1 enhanced PARP1's own poly ADP-ribosylation (PARylation) activity by interacting with PARP1, which in turn promoted autophagy. In vivo experiments showed that knockdown of HKDC1 significantly inhibited the growth of pancreatic cancer cells in nude mice in vivo, reduced tumor volume and weight, and down-regulated the expression of PARP1, LC3, Cyclin D1 and PCNA.

Conclusion

HKDC1 plays a critical role in the malignant progression of PAAD by activating autophagy and promoting cell proliferation. Our findings suggest that targeting HKDC1 and its downstream signaling pathways may provide novel strategies for PAAD treatment.