Epithelial cell adhesion molecule (EpCAM) functions not only in physiological processes but also participates in the development and progression of cancer. In recent decades, extensive efforts have been made to decipher the role of EpCAM in cancers. Great advances have been achieved in elucidating its structure, molecular functions, pathophysiological mechanisms, and clinical applications. Beyond its well-recognized role as a biomarker of cancer stem cells (CSCs) or circulating tumor cells (CTCs), EpCAM exhibits novel and promising value in targeted therapy. At the same time, the roles of EpCAM in cancer progression are found to be highly context-dependent and even contradictory in some cases. The versatile functional modules of EpCAM and its communication with other signaling pathways complicate the study of this molecule. In this review, we start from the structure of EpCAM and focus on communication with other signaling pathways. The impacts on the biology of cancers and the up-to-date clinical applications of EpCAM are also introduced and summarized, aiming to shed light on the translational prospects of EpCAM.

Resistance to anoikis, cell death due to matrix detachment, is acquired during tumor progression. The 14-3-3σ protein is implicated in the development of chemo- and radiation resistance, indicating a poor prognosis in multiple human cancers. However, its function in anoikis resistance and metastasis in hepatocellular carcinoma (HCC) is currently unknown.

Cancer stem cells (CSCs) are central to tumor progression, metastasis, immune evasion, and therapeutic resistance. Characterized by remarkable self-renewal and adaptability, CSCs can transition dynamically between stem-like and differentiated states in response to external stimuli, a process termed “CSC plasticity.” This adaptability underpins their resilience to therapies, including immune checkpoint inhibitors and adoptive cell therapies (ACT). Beyond intrinsic properties, CSCs reside in a specialized microenvironment—the CSC niche—which provides immune-privileged protection, sustains their stemness, and fosters immune suppression. This review highlights the critical role of CSCs and their niche in driving immunotherapy resistance, emphasizing the need for integrative approaches to overcome these challenges.

Transcriptional intermediary factor 1 gamma (TIF1γ) may play either a potential tumor-suppressor or -promoter role in cancer. Here we report on a critical role of TIF1γ in the progression of hepatocellular carcinoma (HCC). Reduced expression of TIF1γ was detected in HCC, especially in advanced HCC tissues, compared to adjacent noncancerous tissues. HCC patients with low TIF1γ expression had shorter overall survival times and higher recurrence rates than those with high TIF1γ expression. Reduced TIF1γ expression was an independent and significant risk factor for recurrence and survival after curative resection. In HCC cells, TIF1γ played a dual role: It promoted tumor growth in early-stage HCC, but not in advanced-stage HCC, whereas it inhibited invasion and metastasis in both early- and advanced-stage HCC. Mechanistically, we confirmed that TIF1γ inhibited transforming growth factor-β/ Drosophila mothers against decapentaplegic protein (TGF-β/Smad) signaling through monoubiquitination of Smad4 and suppressed the formation of Smad2/3/4 complex in HCC cells. TGF-β-inducing cytostasis and metastasis were both inhibited by TIF1γ in HCC. We further proved that TIF1γ suppressed cyotstasis-related TGF-β/Smad downstream c-myc down-regulation, as well as p21/cip1 and p15/ink4b up-regulation in early-stage HCC. Meanwhile, TGF-β inducible epithelial-mesenchymal transition and TGF-β/Smad downstream metastatic cascades, including phosphatase and tensin homolog deleted on chromosome ten down-regulation, chemokine (CXC motif) receptor 4 and matrix metalloproteinase 1 induction, and epidermal growth factor receptor– and protein kinase B–signaling transactivation, were inhibited by TIF1γ. In addition, we found that the down-regulation of TIF1γ in HCC was caused by hypermethylation of CpG islands in the TIF1γ promoter, and demonstrated that the combination of TIF1γ and phosphorylated Smad2 was a more powerful predictor of poor prognosis. Conclusion : TIF1γ regulates tumor growth and metastasis through inhibition of TGF-β/Smad signaling and may serve as a novel prognostic biomarker in HCC. (Hepatology 2014;60:1620–1636)

Objective: The gain of function (GOF) CTNNB1 mutations (CTNNB1 ^GOF ) in hepatocellular carcinoma (HCC) cause significant immune escape and resistance to anti-PD-1. Here, we aimed to investigate the mechanism of CTNNB1 ^GOF HCC-mediated immune escape and raise a new therapeutic strategy to enhance anti-PD-1 efficacy in HCC. Design: RNA sequencing was performed to identify the key downstream genes of CTNNB1 ^GOF associated with immune escape. An in vitro coculture system, murine subcutaneous or orthotopic models, spontaneously tumourigenic models in conditional gene-knock-out mice and flow cytometry were used to explore the biological function of matrix metallopeptidase 9 (MMP9) in tumour progression and immune escape. Single-cell RNA sequencing and proteomics were used to gain insight into the underlying mechanisms of MMP9. Results: MMP9 was significantly upregulated in CTNNB1 ^GOF HCC. MMP9 suppressed infiltration and cytotoxicity of CD8 ⁺ T cells, which was critical for CTNNB1 ^GOF to drive the suppressive tumour immune microenvironment (TIME) and anti-PD-1 resistance. Mechanistically, CTNNB1 ^GOF downregulated sirtuin 2 (SIRT2), resulting in promotion of β-catenin/lysine demethylase 4D (KDM4D) complex formation that fostered the transcriptional activation of MMP9. The secretion of MMP9 from HCC mediated slingshot protein phosphatase 1 (SSH1) shedding from CD8 ⁺ T cells, leading to the inhibition of C-X-C motif chemokine receptor 3 (CXCR3)-mediated intracellular of G protein-coupled receptors signalling. Additionally, MMP9 blockade remodelled the TIME and potentiated the sensitivity of anti-PD-1 therapy in HCC. Conclusions: CTNNB1 ^GOF induces a suppressive TIME by activating secretion of MMP9. Targeting MMP9 reshapes TIME and potentiates anti-PD-1 efficacy in CTNNB1 ^GOF HCC.

Background: N4‐acetylcytidine (ac4C) represents a novel messenger RNA (mRNA) modification, and its associated acetyltransferase N‐acetyltransferase 10 (NAT10) plays a crucial role in the initiation and progression of tumors by regulating mRNA functionality. However, its role in hepatocellular carcinoma (HCC) development and prognosis is largely unknown. This study aimed to elucidate the role of NAT10‐mediated ac4C in HCC progression and provide a promising therapeutic approach. Methods: The ac4C levels were evaluated by dot blot and ultra‐performance liquid chromatography‐tandem mass spectrometry with harvested HCC tissues. The expression of NAT10 was investigated using quantitative real‐time polymerase chain reaction, western blotting, and immunohistochemical staining across 91 cohorts of HCC patients. To explore the underlying mechanisms of NAT10‐ac4C in HCC, we employed a comprehensive approach integrating acetylated RNA immunoprecipitation and sequencing, RNA sequencing and ribosome profiling analyses, along with RNA immunoprecipitation, RNA pull‐down, mass spectrometry, and site‐specific mutation analyses. The drug affinity responsive targets stability, cellular thermal shift assay, and surface plasmon resonance assays were performed to assess the specific binding of NAT10 and Panobinostat. Furthermore, the efficacy of targeting NAT10‐ac4C for HCC treatment was elucidated through in vitro experiments using HCC cells and in vivo HCC mouse models. Results: Our investigation revealed a significant increase in both the ac4C RNA level and NAT10 expression in HCC. Notably, elevated NAT10 expression was associated with poor outcomes in HCC patients. Functionally, silencing NAT10 suppressed HCC proliferation and metastasis in vitro and in vivo. Mechanistically, NAT10 stimulates the ac4C modification within the coding sequence (CDS) of high mobility group protein B2 (HMGB2), which subsequently enhances HMGB2 translation by facilitating eukaryotic elongation factor 2 (eEF2) binding to the ac4C sites on HMGB2 mRNA's CDS. Additionally, high‐throughput compound library screening revealed Panobinostat as a potent inhibitor of NAT10‐mediated ac4C modification. This inhibition significantly attenuated HCC growth and metastasis in both in vitro experiments using HCC cells and in vivo HCC mouse models. Conclusions: Our study identified a novel oncogenic epi‐transcriptome axis involving NAT10‐ac4C/eEF2‐HMGB2, which plays a pivotal role in regulating HCC growth and metastasis. The drug Panobinostat validates the therapeutic potential of targeting this axis for HCC treatment.