HBV X protein regulates cancer stemness and tumor invasiveness through SENP1 in hepatocellular carcinoma

BACKGROUND & AIMS: The niche in hepatocellular carcinoma (HCC) critically influences cancer stem cell (CSC)-associated properties, including stemness, early recurrence, and poor prognoses. HBV infection acts as a niche driver for tumor progression and malignancy. While the HBV X (HBx) protein has been linked to CSC-associated properties, the underlying molecular mechanisms remain unclear.

METHODS: Paired tumor and peritumor tissues from 211 patients with HCC were analyzed to correlate SENP1, OCT4, SNAIL, PIN1, and TWIST expression with overall survival (OS) and disease-free survival (DFS) using a Kaplan-Meier survival analysis. Validation was performed using HCC microarray data (n = 167). HBx-SENP1's role in regulating CSC-associated properties was examined in vitro (stemness expression, sphere formation, CD133 + cells, migration/invasion, and sorafenib sensitivity) and in vivo using an orthotopic xenograft model.

RESULTS: Clinically, SENP1 expression was correlated with OCT4, SNAIL, and TWIST ( p <0.001), and was associated with poor OS (69.2 vs. 172.8 months, p <0.001) and DFS (15.8 vs. 39.7 months, p <0.001). SENP1 expression was correlated with gene sets linked to HCC recurrence and embryonic stem cell signatures. In HBV-related HCC, elevated SENP1 (7.8 vs. 15.7 months, p = 0.003), OCT4 (7.8 vs. 16.7 months, p <0.001), SNAIL (8.6 vs. 15.7 months, p = 0.012), and TWIST (8.2 vs. 15.5 months, p = 0.028) were linked to early recurrence. Mechanistically, HBx induced CSC-associated properties through SENP1, including sphere formation, CD133 + cells, migration/invasion, and sorafenib resistance. SENP1-knockdown decreased HBx-induced pulmonary metastases and sorafenib refractoriness in vivo.

CONCLUSIONS: HBx-induced SENP1 is critical for CSC properties. SENP1 can serve as a novel biomarker for early recurrence, metastasis, and drug resistance, particularly in HBV-related HCC.

IMPACT AND IMPLICATIONS: Early recurrence, tumor metastasis, and drug resistance are significant therapeutic challenges in hepatocellular carcinoma (HCC), which are closely associated with cancer stem cell (CSC)-related properties. In this study, we demonstrated that HBx-induced SENP1 expression regulates CSC-related properties and tumor metastasis, particularly in HBV-related HCC, in clinical, in vitro, and in vivo settings. Findings from this research highlight that HBx-induced SENP1 is crucial for promoting CSC-associated properties in HCC. SENP1 could serve as a novel biomarker of early tumor recurrence and metastasis, especially for HBV-related HCC.