Programmed cell death protein 5 inhibits hepatocellular carcinoma progression by inducing pyroptosis through regulation of TGF-β/Smad2/3/Snail pathway

Background

Programmed cell death protein 5 (PDCD5) is involved in apoptosis and is regarded as a tumor suppressor in various tumors. However, its role and underlying molecular mechanisms in hepatocellular carcinoma (HCC) remain unclear.

Methods

PDCD5-overexpressing cell and xenograft tumor models were developed. Cell Counting Kit-8, 5-Ethynyl-2′-deoxyuridine, wound healing, Transwell, flow cytometry, immunohistochemistry, and hematoxylin-eosin staining were employed to explore the effects of PDCD5 on HCC cell behaviors and tumor growth. The enzyme-linked immunosorbent assay and western blot were used to detect pyroptosis-related marker levels. The molecular mechanisms underlying PDCD5's role in HCC were investigated through transcriptome sequencing and coimmunoprecipitation. SRI-011381, a TGF-β signaling activator, was applied to evaluate the impact of PDCD5 in modulating the TGF-β/Smad2/3/Snail pathway.

Results

PDCD5 expression was reduced in HCC cells. Overexpression of PDCD5 inhibited HCC cell proliferation, migration, invasion, and xenograft tumor growth. Additionally, PDCD5 overexpression promoted apoptosis and pyroptosis, with corresponding increases in inflammatory factors and Caspase-1, GSDMD, and NLRP3 protein levels. Mechanistically, PDCD5 bound to receptor-regulated Smads (Smad2/3), inhibiting the TGF-β pathway. Treatment with the TGF-β pathway activator SRI-011381 significantly counteracted the inhibitory effects of PDCD5 overexpression on HCC progression.

Conclusion

Our findings suggest that PDCD5 impedes the progression of HCC by promoting pyroptosis via regulation of TGF-β/Smad2/3/Snail pathway, which could be a possible therapeutic target for HCC.