Lenvatinib inhibited HCC cell migration and invasion through regulating the transcription and ubiquitination of UHRF1 and DNMT1

Targeted silencing of SOCS1 by DNMT1 promotes stemness of human liver cancer stem-like cells

BACKGROUND

Human liver cancer stem-like cells (HLCSLCs) are widely acknowledged as significant factors in the recurrence and eradication of hepatocellular carcinoma (HCC). The sustenance of HLCSLCs' stemness is hypothesized to be intricately linked to the epigenetic process of DNA methylation modification of genes associated with anticancer properties. The present study aimed to elucidate the stemness-maintaining mechanism of HLCSLCs and provide a novel idea for the clearance of HLCSLCs.

METHODS

The clinical relevance of DNMT1 and SOCS1 in hepatocellular carcinoma (HCC) patients was evaluated through the GEO and TCGA databases. Cellular immunofluorescence assay, methylation-specific PCR, chromatin immunoprecipitation were conducted to explore the expression of DNMT1 and SOCS1 and the regulatory relationship between them in HLCSLCs. Spheroid formation, soft agar colony formation, expression of stemness-associated molecules, and tumorigenicity of xenograft in nude mice were used to evaluate the stemness of HLCSLCs.

RESULTS

The current analysis revealed a significant upregulation of DNMT1 and downregulation of SOCS1 in HCC tumor tissues compared to adjacent normal liver tissues. Furthermore, patients exhibiting an elevated DNMT1 expression or a reduced SOCS1 expression had low survival. This study illustrated the pronounced expression and activity of DNMT1 in HLCSLCs, which effectively targeted the promoter region of SOCS1 and induced hypermethylation, consequently suppressing the expression of SOCS1. Notably, the stemness of HLCSLCs was reduced upon treatment with DNMT1 inhibitors in a concentration-dependent manner. Additionally, the overexpression of SOCS1 in HLCSLCs significantly mitigated their stemness. The knockdown of SOCS1 expression reversed the effect of DNMT1 inhibitor on the stemness of HLCSLCs. DNMT1 directly binds to the SOCS1 promoter. In vivo, DNMT1 inhibitors suppressed SOCS1 expression and inhibited the growth of xenograft.

CONCLUSION

DNMT1 targets the promoter region of SOCS1, induces hypermethylation of its CpG islands, and silences its expression, thereby promoting the stemness of HLCSLCs.

Recent Insights into the Roles of PEST-Containing Nuclear Protein

PEST-containing nuclear protein (PCNP), a short-lived small nuclear protein with 178 amino acids, is a nuclear protein containing two PEST sequences. PCNP is highly expressed in several malignant tumors such as cervical cancer, rectal cancer, and lung cancer. It is also associated with cell cycle regulation and the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) and Wnt signaling pathways during tumor growth. The present article discuss how PCNP regulates the PI3K/AKT/mTOR and Wnt signaling pathways and related proteins, and the ubiquitination of PCNP regulates tumor cell cycle as well as the progress of the application of PCNP in the pathophysiology and treatment of colon cancer, human ovarian cancer, thyroid cancer, lung adenocarcinoma and oral squamous cell carcinoma. The main relevant articles were retrieved from PubMed, with keywords such as PEST-containing nuclear protein (PCNP), cancer (tumor), and signaling pathways as inclusion/exclusion criteria. Relevant references has been included and cited in the manuscript.

Roles of post-translational modifications of UHRF1 in cancer

UHRF1 as a member of RING-finger type E3 ubiquitin ligases family, is an epigenetic regulator with five structural domains. It has been involved in the regulation of a series of biological functions, such as DNA replication, DNA methylation, and DNA damage repair. Additionally, aberrant overexpression of UHRF1 has been observed in over ten cancer types, indicating that UHRF1 is a typical oncogene. The overexpression of UHRF1 repressed the transcription of such tumor-suppressor genes as CDKN2A, BRCA1, and CDH1 through DNMT1-mediated DNA methylation. In addition to the upstream transcription factors regulating gene transcription, post-translational modifications (PTMs) also contribute to abnormal overexpression of UHRF1 in cancerous tissues. The types of PTM include phosphorylation, acetylation, methylationand ubiquitination, which regulate protein stability, histone methyltransferase activity, intracellular localization and the interaction with binding partners. Recently, several novel PTM types of UHRF1 have been reported, but the detailed mechanisms remain unclear. This comprehensive review summarized the types of UHRF1 PTMs, as well as their biological functions. A deep understanding of these crucial mechanisms of UHRF1 is pivotal for the development of novel UHRF1-targeted anti-cancer therapeutic strategies in the future.

Advances in Targeted Drug Resistance Associated with Dysregulation of Lipid Metabolism in Hepatocellular Carcinoma

Hepatocellular carcinoma is the prevailing malignant neoplasm affecting the liver, often diagnosed at an advanced stage and associated with an unfavorable overall prognosis. Sorafenib and Lenvatinib have emerged as first-line therapeutic drugs for advanced hepatocellular carcinoma, improving the prognosis for these patients. Nevertheless, the issue of tyrosine kinase inhibitor (TKI) resistance poses a substantial obstacle in the management of advanced hepatocellular carcinoma. The pathogenesis and advancement of hepatocellular carcinoma exhibit a close association with metabolic reprogramming, yet the attention given to lipid metabolism dysregulation in hepatocellular carcinoma development remains relatively restricted. This review summarizes the potential significance and research progress of lipid metabolism dysfunction in Sorafenib and Lenvatinib resistance in hepatocellular carcinoma. Targeting hepatocellular carcinoma lipid metabolism holds promising potential as an effective strategy to overcome hepatocellular carcinoma drug resistance in the future.

Systematic Characterization of DNA Methyltransferases Family in Tumor Progression and Antitumor Immunity

Objective: DNA methylation is an essential epigenetic marker governed by DNA methyltransferases (DNMTs), which can influence cancer onset and progression. However, few studies have provided an integrated analysis of the relevance of DNMT family genes to cell stemness, the tumor microenvironment (TME), and immunotherapy biomarkers across diverse cancers. Methods: This study investigated the impact of five DNMTs on transcriptional profiles, prognosis, and their association with Ki67 expression, epithelial-mesenchymal transition signatures, stemness scores, the TME, and immunological markers across 31 cancer types from recognized public databases. Results: The results indicated that DNMT1/DNMT3B/DNMT3A expression increased, whereas TRDMT1/DNMT3L expression decreased in most cancer types. DNMT family genes were identified as prognostic risk factors for numerous cancers, as well as being prominently associated with immune, stromal, and ESTIMATE scores, as well as with immune-infiltrating cell levels. Expression of the well-known immune checkpoints, PDCD1 and CILA4, was noticeably related to DNMT1/DNMT3A/DNMT3B expression. Finally, we validated the role of DNMT1 in MCF-7 and HepG2-C3A cell lines through its knockdown, whereafter a decrease in cell proliferation and migration ability in vitro was observed. Conclusion: Our study comprehensively expounded that DNMT family genes not only behave as promising prognostic factors but also have the potential to serve as therapeutic targets in cancer immunotherapy for various types of cancer.

UHRF1 inhibition epigenetically reprograms cancer stem cells to suppress the tumorigenic phenotype of hepatocellular carcinoma

Cancer stem cells (CSCs) contribute to tumor initiation, progression, and recurrence in many types of cancer, including hepatocellular carcinoma (HCC). Epigenetic reprogramming of CSCs has emerged as a promising strategy for inducing the transition from malignancy to benignity. Ubiquitin-like with PHD and ring finger domains 1 (UHRF1) is required for DNA methylation inheritance. Here, we investigated the role and mechanism of UHRF1 in regulating CSC properties and evaluated the impact of UHRF1 targeting on HCC. Hepatocyte-specific Uhrf1 knockout (Uhrf1^HKO) strongly suppressed tumor initiation and CSC self-renewal in both diethylnitrosamine (DEN)/CCl₄-induced and Myc-transgenic HCC mouse models. Ablation of UHRF1 in human HCC cell lines yielded consistent phenotypes. Integrated RNA-seq and whole genome bisulfite sequencing revealed widespread hypomethylation induced by UHRF1 silencing epigenetically reprogrammed cancer cells toward differentiation and tumor suppression. Mechanistically, UHRF1 deficiency upregulated CEBPA and subsequently inhibited GLI1 and Hedgehog signaling. Administration of hinokitiol, a potential UHRF1 inhibitor, significantly reduced tumor growth and CSC phenotypes in mice with Myc-driven HCC. Of pathophysiological significance, the expression levels of UHRF1, GLI1, and key axis proteins consistently increased in the livers of mice and patients with HCC. These findings highlight the regulatory mechanism of UHRF1 in liver CSCs and have important implications for the development of therapeutic strategies for HCC.

Secukinumab plays a synergistic role with starvation therapy in promoting autophagic cell death of hepatocellular carcinoma via inhibiting IL-17A-increased BCL2 level

It is known that IL-17A inhibits autophagy of hepatocellular carcinoma (HCC) cells, thus contributing to the carcinogenesis of HCC. Starvation therapy can promote the autophagic death of HCC cells by blocking the nutrition supply. The purpose of this study was to explore whether the pharmacological antagonist of IL-17A, secukinumab, and starvation therapy have a synergistic effect on the autophagic cell death of HCC. Here, it could be observed that compared with serum-free condition, the combination of secukinumab and serum-free status better promoted autophagy (observed by LC3 conversion rate, p62 protein expression and the formation of autophagosomes), and more significantly inhibited the survival and function (observed by Trypan blue staining, CCK-8, Transwell, and scratch assays) in HCC HepG2 cells. Moreover, secukinumab significantly decreased BCL2 protein expression under serum-normal and serum-free conditions. However, both the addition of recombinant IL-17A and overexpression of BCL2 blocked the regulation of secukinumab on the survival and autophagy in HepG2 cells. Nude mice experiments demonstrated that compared to the lenvatinib-alone group, the combination group of lenvatinib and secukinumab better inhibited the in vivo tumorigenesis of HepG2 cells and enhanced autophagy in xenotumor tissues. Furthermore, secukinumab significantly decreased BCL2 protein expression in xenotumor tissues without or with lenvatinib application. In conclusion, the antagonism of IL-17A with secukinumab, due to the upregulation on BCL2-related autophagic cell death, can cooperate with starvation therapy in inhibiting HCC carcinogenesis. Our data suggested that secukinumab can become an effective adjuvant for the treatment of HCC.