Suiyi Wu

The overall response rate for anti-PD-1 therapy remains modest in hepatocellular carcinoma (HCC). We found that a combination of IFNα and anti-PD-1-based immunotherapy resulted in enhanced antitumor activity in patients with unresectable HCC. In both immunocompetent orthotopic and spontaneous HCC models, IFNα therapy synergized with anti-PD-1 and the combination treatment led to significant enrichment of cytotoxic CD27+CD8+ T cells. Mechanistically, IFNα suppressed HIF1α signaling by inhibiting FosB transcription in HCC cells, resulting in reduced glucose consumption capacity and consequentially establishing a high-glucose microenvironment that fostered transcription of the T-cell costimulatory molecule Cd27 via mTOR-FOXM1 signaling in infiltrating CD8+ T cells. Together, these data reveal that IFNα reprograms glucose metabolism within the HCC tumor microenvironment, thereby liberating T-cell cytotoxic capacities and potentiating the PD-1 blockade-induced immune response. Our findings suggest that IFNα and anti-PD-1 cotreatment is an effective novel combination strategy for patients with HCC. SIGNIFICANCE: Our study supports a role of tumor glucose metabolism in IFNα-mediated antitumor immunity in HCC, and tumor-infiltrating CD27+CD8+ T cells may be a promising biomarker for stratifying patients for anti-PD-1 therapy. See related commentary by Kao et al., p. 1615. This article is highlighted in the In This Issue feature, p. 1599.

Abstract Background The efficacy of immune checkpoint blockade therapy in patients with hepatocellular carcinoma (HCC) remains poor. Although serine‐ and arginine‐rich splicing factor (SRSF) family members play crucial roles in tumors, their impact on tumor immunology remains unclear. This study aimed to elucidate the role of SRSF10 in HCC immunotherapy. Methods To identify the key genes associated with immunotherapy resistance, we conducted single‐nuclear RNA sequencing, multiplex immunofluorescence, and The Cancer Genome Atlas and Gene Expression Omnibus database analyses. We investigated the biological functions of SRSF10 in immune evasion using in vitro co‐culture systems, flow cytometry, various tumor‐bearing mouse models, and patient‐derived organotypic tumor spheroids. Results SRSF10 was upregulated in various tumors and associated with poor prognosis. Moreover, SRSF10 positively regulated lactate production, and SRSF10/glycolysis/ histone H3 lysine 18 lactylation (H3K18la) formed a positive feedback loop in tumor cells. Increased lactate levels promoted M2 macrophage polarization, thereby inhibiting CD8 + T cell activity. Mechanistically, SRSF10 interacted with the 3′‐untranslated region of MYB , enhancing MYB RNA stability, and subsequently upregulating key glycolysis‐related enzymes including glucose transporter 1 ( GLUT1 ), hexokinase 1 ( HK1 ), lactate dehydrogenase A ( LDHA ), resulting in elevated intracellular and extracellular lactate levels. Lactate accumulation induced histone lactylation, which further upregulated SRSF10 expression. Additionally, lactate produced by tumors induced lactylation of the histone H3K18la site upon transport into macrophages, thereby activating transcription and enhancing pro‐tumor macrophage activity. M2 macrophages, in turn, inhibited the enrichment of CD8 + T cells and the proportion of interferon‐γ + CD8 + T cells in the tumor microenvironment (TME), thus creating an immunosuppressive TME. Clinically, SRSF10 could serve as a biomarker for assessing immunotherapy resistance in various solid tumors. Pharmacological targeting of SRSF10 with a selective inhibitor 1C8 enhanced the efficacy of programmed cell death 1 (PD‐1) monoclonal antibodies (mAbs) in both murine and human preclinical models. Conclusions The SRSF10/MYB/glycolysis/lactate axis is critical for triggering immune evasion and anti‐PD‐1 resistance. Inhibiting SRSF10 by 1C8 may overcome anti‐PD‐1 tolerance in HCC.

RATIONALE: CD13 is a new marker for liver cancer stem cells (CSCs) that contributes to sorafenib resistance in hepatocellular carcinoma (HCC). However, the underlying mechanism of CD13 in HCC sorafenib resistance remains enigmatic. METHODS: The expression of CD13 in HCC cell lines and tissues was assayed by RT-PCR, western-blot, and immunohistochemistry staining. Athymic BALB/c nu/nu mice model was used to study the in vivo functions of CD13. Clinical significance of CD13 was evaluated by Kaplan-Meier methods. Cellular proliferation rate was evaluated by cell counting kit-8 cell proliferation assay and colony formation assay. Tunel assay was used to detect cell death ratio. Transwell assay was used to evaluate the motility of cells. Immunoprecipitation (IP), liquid chromatography-mass spectrometry (LC-MS)/MS, and co-IP were applied to investigate potential protein interactions of CD13. RESULTS: In this research, we found that CD13 expression was higher in metastatic HCC samples, and its overexpression was predicted worse prognosis for patients after surgical resection. Functionally, CD13 promoted HCC proliferation, invasion, cell cycle progression as well as sorafenib resistance. Mechanistically, CD13 interacted with histone deacetylase5 (HDAC5) to promote its protein stability, thus resulting in HDAC5-mediated lysine-specific demethylase 1 (LSD1) deacetylation and protein stabilization. Consequently, LSD1 decreased the NF-κB catalytic unit p65 methylation that led to p65 protein stability. A CD13 inhibitor ubenimex in combination with sorafenib, suppressed the tumor growth and attenuated the resistance of HCC cells toward sorafenib in patient-derived xenograft models. CONCLUSIONS: CD13 promotes HCC progression and induces sorafenib resistance, mainly via interacting with HDAC5 to prevent the degradation of p65 and activate NF-kB signaling pathway. CD13 is a prognostic indicator for HCC patients underwent curative resection as well as a predictor of response to treatment with sorafenib. Our study establishes the new therapeutic potential of targeting CD13-HDAC5-LSD1-NF-κB in HCC.

BACKGROUND & AIMS: Liver transplantation (LTx) is one of the most effective treatments for hepatocellular carcinoma (HCC); however, tumour recurrence after LTx often leads to poor outcomes. This study investigated the value of circulating tumour cells (CTCs) as a predictor of recurrence following LTx in patients with HCC. METHODS: This analysis included 193 patients with HCC who underwent LTx at our institute and accepted pre- and post-operative CTC detection; 38 were selected for serial CTC monitoring. The predictive value of CTCs for tumour recurrence in patients with HCC following LTx was evaluated. Single-cell whole genome sequencing was used to characterize CTCs. RESULTS: Overall, the CTC burden decreased after LTx (P < .05). Post-operative CTC count ≥ 1 per 5 mL peripheral blood was identified as a potential biomarker for predicting tumour recurrence after LTx, especially in patients with no detectable CTCs prior to LTx and negative tumour serological biomarkers. The predictive value of post-operative CTC count ≥ 1 per 5 mL blood was retained in patients who did not meet the Milan criteria, University of California San Francisco (UCSF) criteria, or Fudan criteria (all P < .05). Furthermore, post-operative serial CTC detection may be useful in post-surgical surveillance for HCC recurrence. CONCLUSIONS: CTCs may be a useful biomarker to evaluate recurrence risk following LTx in patients with HCC. Evaluation based on CTC detection may enhance the post-transplant management of HCC, and improve the therapeutic efficacy of LTx.

Background: Current treatment options for intrahepatic cholangiocarcinoma (ICC) are limited by the lack of understanding of the disease pathogenesis. It has been known that mucin 1 (MUC1) is a cell surface mucin that highly expressed in various cancer tissues. However, its role in ICC has not been well studied. The purpose of this study was to investigate the clinical significance and biological function of MUC1 in ICC. Methods: qRT-PCR and western blot assays were performed to examine MUC1 expression. RNA-Seq (RNA Sequencing) s conducted to explore the RNA expression. A tissue microarray study including 214 ICC cases was also conducted to evaluate the clinical relevance and prognostic significance of MUC1. The role and underlying mechanisms of MUC1 in regulating cell growth and invasion were further explored both in vitro and in vivo models. Results: The mRNA and protein levels of MUC1 were significantly up-regulated in ICC compared to paired non-tumor tissues. Depletion of MUC1 in HCCC9810 cells significantly inhibited cell proliferation, migration and invasion in vitro and overexpression of MUC1 in RBE cells resulted in increased cell proliferation, migration and invasion. Both univariate and multivariate analysis revealed that the protein expression of MUC1 was associated with overall survival and relapse-free survival after tumor resection. Clinically, high MUC1 expression was more commonly observed in aggressive tumors. Further studies indicated that MUC1 exerted its function through activating Wnt/ -catenin pathway.