Human HCC Research Articles

SIRT7 stabilizes β-catenin and promotes canonical Wnt activation via upregulating FZD7

AimsThe dysregulated Wnt/β-Catenin signaling pathway leads to occurrence of various diseases, and abnormal activation of β-Catenin is a major characteristic of human HCC. FZD7 is a positive regulator of the Wnt/β-catenin signaling pathway, and its upregulation is related to increase of β-catenin expression and carcinogenesis in human HCC. However, mechanisms underlying FZD7 upregulation in HCC remain elusive. Main methodsNuclear cytosol fractionation, immunofluorescence and Top-Flash were used to detect the activation of β-Catenin. Protein half-life and ubiquitination assays were applied to evaluate protein stability. RNA-seq combined with qRT-PCR was used to evaluate differential gene expressions after SIRT7 knockdown. Wound healing and transwell assays were used to measure cancer cell migration. Key findingsSIRT7-mediated FZD7 expression is essential for stability and activation of β-catenin. Knockdown SIRT7 in HCC cells resulted in enhanced binding of β-catenin to the DC, decreased its stability, nuclear localization and activation. Knockdown FZD7 reversed SIRT7 overexpression mediated β-catenin stabilization and impairment of binding of β-catenin to the DC. At molecular level, SIRT7 promotes FZD7 expression via upregulating transcription factor PU.1, knockdown PU.1 abolished SIRT7-mediated upregulation of FZD7. Finally, we confirmed that FZD7 was responsible for SIRT7-mediated β-catenin stabilization and HCC cells migration. By using clinical samples, we observed strong positive correlations between SIRT7 and PU.1, FZD7, p-GSK3β and β-Catenin in human HCC. SignificanceOur results thus revealed a previously undisclosed role of SIRT7 in regulating the canonical Wnt/β-catenin signaling pathway, thereby offering additional evidence that SIRT7 holds promise as a novel therapeutic target for human HCC.

-RAMP3 promotes hepatocellular carcinoma tumor cell-mediated CCL2 degradation by supporting membrane distribution of ACKR2

This study aimed to explore the potential bind of Receptor Activity-Modifying Protein 3 (RAMP3) with atypical chemokine receptor 2 (ACKR2), and their cooperative regulation on the degradation of the immunosuppressive chemokine CCL2 in the tumor microenvironment of HCC. Bioinformatic analysis was conducted using available bulk-tissue RNA-seq, single-cell RNA-seq, and protein–protein interaction datasets. Human HCC cell line Huh7 and HepG2 and mouse HCC cell line Hepa1-6 were utilized for experiments. Results showed that RAMP3 binds with ACKR2 in HCC tumor cells and promotes the membrane distribution of ACKR2 through RAB4-positive vesicles. RAMP3 promotes CCL2 scavenging through ACKR2 in HCC cells. Mouse RAMP3 inhibited the proliferation of mouse liver cancer cell line (Hepa1-6)-derived syngeneic tumors through ACKR2, reduced the intratumoral concentration of CCL2 in the tumor, and inhibited the phosphorylation of Signal Transducer and Activator of Transcription 3 (STAT3) and protein kinase B (AKT). In addition, mouse RAMP3 inhibited CD11b+/Gr-1 + myeloid cell infiltration and neovascularization in the tumors through ACKR2. In TCGA-LIHC, RAMP3low/ACKR2low group had the worst progression-free interval (PFI), while the RAMP3high/ACKR2high group had the best overall survival (OS). In summary, restoring RAMP3 expression in HCC cells may generate synergistic support for the anticancer effect of ACKR2.

The TGF-β1 target WISP1 is highly expressed in liver cirrhosis and cirrhotic HCC microenvironment and involved in pro- and anti-tumorigenic effects

IntroductionWNT1-inducible signalling pathway protein 1 (WISP1) promotes progression of several tumor entities often correlating with worse prognosis. Here its expression regulation and role in the progression of chronic liver diseases (CLD) was investigated. MethodsWISP1 expression was analyzed in human HCC datasets, in biopsies and serum samples and an HCC patient tissue microarray (TMA) including correlation to clinicopathological parameters. Spatial distribution of WISP1 expression was determined using RNAscope analysis. Regulation of WISP1 expression was investigated in cytokine-stimulated primary mouse hepatocytes (PMH) by array analysis and qRT-PCR. Outcome of WISP1 stimulation was analyzed by IncuCyte S3-live cell imaging, qRT-PCR, and immunoblotting in murine AML12 cells. ResultsIn a TMA, high WISP1 expression was positively correlated with early HCC stages and male sex. Highest WISP1 expression levels were detected in patients with cirrhosis as compared to healthy individuals, patients with early fibrosis, and non-cirrhotic HCC in liver biopsies, expression datasets and serum samples. WISP1 transcripts were predominantly detected in hepatocytes of cirrhotic rather than tumorous liver tissue. High WISP1 expression was associated with better survival. In PMH, AML12 and HepaRG, WISP1 was identified as a specific TGF-β1 target gene. Accordingly, expression levels of both cytokines positively correlated in human HCC patient samples. WISP1-stimulation induced the expression of Bcl-xL, PCNA and p21 in AML12 cells. ConclusionsWISP1 expression is induced by TGF-β1 in hepatocytes and is associated with cirrhotic liver disease. We propose a crucial role of WISP1 in balancing pro- and anti-tumorigenic effects during premalignant stages of CLD.

Combined neurokinin-1 receptor antagonist and sorafenib is a promising approach for hepatocellular carcinoma therapy

BackgroundHCC (Hepatocellular carcinoma) is the most common primary malignant cancer in the liver. Treatment options to incurable HCC such as sorafenib, an oral multikinase inhibitor, had numerous side effects and questionable effectiveness. Neurokinin-1 receptor (NK1R) have a major role in inflammation and tumour environment including the resistance to cell death, the induction of angiogenesis and the promotion of cell migration and proliferation. Additionally, NK-1R is over-expressed in human tumour cells including HCC. Moreover, Aprepitant, one of the NK-1R antagonists exerts multiple antitumor activities (antiproliferative, apoptotic, antimigration, and antiangiogenesis) in vivo and in vitro.Study aimTo analyze the effectiveness of combining sorafenib with aprepitant in the management of HCC (experimental).Patients and methodsIn this retrospective experimental study, the human HCC cell line, HepG2, cells were exposed to increasing concentrations of sorafenib alone, aprepitant alone and combination of both sorafenib and aprepitant evaluation of cytotoxicity, apoptosis, MMP-9, VEGF, NF-kB p-65, p-AKT and p-ERK were done. Moreover, The extent of the NK-1 receptor expression was assessed by immunocytochemistry on 50 HCC paraffin blocks of Egyptian HCC patients and another 50 paraffin blocks of liver cirrhosis only as a control.ResultsDecreased levels of MMP-9, VEGF, NF-kB p-65, p-AKT and p-ERK was more substantial in the combination therapy compared to sorafenib alone and aprepitant alone. Moreover, the rate of apoptosis and cytotoxicity were significantly higher in the combination treatment group than the monotherapy groups with more anti inflammatory, anti angiogentic and anti metastatic effects. Also, among the 50 HCC paraffin blocks, the majority (60%) showed a strong NK-1 expression; which significantly (p < 0.05) correlated with the progression free survival (PFS) but not the overall survival (OS) of the patients when applying multivariate analysis.ConclusionHCC had strong expression and immunostaining for NK1R.Therefore, combined aprepitant and sorafenib may be a promising approach in HCC treatment compared to each one alone.

Loss of FAM172A gene prompts cell proliferation in liver regeneration.

The present study was designed to explore the function of FAM172A in liver regeneration and HCC. Mice were sacrificed after 70% partial hepatectomy (PH). RNA sequencing was performed on primary hepatocytes of WT and FAM172A-/- mice. We used HepG2 cells to construct cell lines with stably knockdown and overexpression of FAM172A. The expression of FAM172A in liver tissues was investigated by immunohistochemical staining, and we also used public database to perform survival analysis and prognostic model in HCC. Compared with WT mice after PH, normalized liver weight/body weight (LW/BW) ratio and the proliferating cell nuclear antigen (PCNA) protein level of FAM172A-/- mice elevated. The DEGs were mainly enriched in inflammatory response, tumor necrosis factor production, and wound healing. FAM172A knockdown enhanced the NFκB-TNFα and pERK-YAP1-Cyclin D1 axis. FAM172A peptide inhibited proliferation of primary hepatocytes. Moreover, the low expression of FAM172A in human HCC tissues implies a lower likelihood of survival and a valid diagnostic marker for HCC. Loss of FAM172A gene promotes cell proliferation by pERK-YAP1-Cyclin D1 and pNFκB-TNFα pathways during liver regeneration after PH. FAM172A may be a favorable diagnosis marker of HCC.

Caspases compromise SLU7 and UPF1 stability and NMD activity during hepatocarcinogenesis

Background & AimsThe homeostasis of the cellular transcriptome depends on transcription and splicing mechanisms. Moreover, the fidelity of gene expression, essential to preserve cellular identity and function is secured by different quality control mechanisms including nonsense-mediated RNA decay (NMD). In this context, alternative splicing is coupled to NMD, and several alterations in these mechanisms leading to the accumulation of aberrant gene isoforms have been involved in human disease including cancer. MethodsRNAseq, Westen blot, qPCR, co-IP in multiple silenced culture cell lines (replicates n≥4), primary hepatocytes and samples of animal models (Jo2, APAP, Mdr2-/- mice, n≥3). ResultsHere we describe that in animal models of liver injury and in human HCC (TCGA, NT =50 vs HCC =374), the process of NMD is inhibited. Moreover, we demonstrate that the splicing factor SLU7 interacts with and preserves the levels of the NMD effector UPF1, and that SLU7 is required for a correct NMD. Our previous findings demonstrated that SLU7 expression is reduced in the diseased liver, contributing to hepatocellular de-differentiation and genome instability during disease progression. However, little was known about the mechanisms underlying SLU7 downregulation. Here we provide evidence showing that caspases activated during liver damage would be responsible of the cleavage and degradation of SLU7. ConclusionsHere we identify the downregulation of UPF1 and the inhibition of NMD as a new molecular pathway contributing to the malignant reshaping of the liver transcriptome. Moreover, and importantly, we uncover caspases activation as the mechanism responsible for the downregulation of SLU7 expression during liver disease progression, which is a new link between apoptosis an hepatocarcinogenesis. Impact and implicationsThe mechanisms involved in the reshaping of hepatocellular transcriptome driving the progressive loss of cell identity and function in liver disease are not completely understood. In this context, we provide evidence on the impairment of a key mRNA surveillance mechanism known as nonsense-mediated mRNA decay (NMD). Mechanistically, we uncover a novel role for the splicing factor SLU7 in the regulation of NMD, including its ability to interact and preserve the levels the key NMD factor UPF1. Moreover, we demonstrate that the activation of caspases during liver damage mediates SLU7 and UPF1 proteins degradation and NMD inhibition. Our findings identify potential new markers of liver disease progression, and SLU7 as a novel therapeutic target to prevent the functional decay of the chronically injured organ.

Material basis revelation of anti-hepatoma effect of Huachansu (Cinobufacini) through down-regulation of thymidylate synthase

ObjectiveHepatocellular carcinoma (HCC) is a leading cause of mortality worldwide. Huachansu (Cinobufacini) is active extract isolated from the dry skin of Bufo Bufo gargarizans. It has now been widely used in clinical treatment of cancer, this study is to clarify the material basis of down-regulation of thymidylate synthase (TYMS) induced by Huachansu. MethodsOur study utilized UPLC-MS/MS to identify major bioactive components from Huachansu. Cell Counting Kit 8 (CCK-8) assay and clone formation assay were used to examine the cell viability of tumor cells. TYMS and γ-H2AX level were detected by using quantitative real-time RT-PCR and/or western blotting. Small interfering RNA (siRNA) transfection was used to explore whether inhibition of TYMS could enhance the suppressive effect of Huachansu on cell growth of HCC cells. ResultsIn our study, firstly, we identify 21 major bioactive components from Huachansu. CCK-8 assay results showed that Huachansu and its bioactive bufadienolides (Bufalin, Bufotalin, Cinobufotalin, Desacetylcinobufagin, Arenobufagin, Telocinobufagin, and Resibufogenin) significantly inhibited the proliferation of HepG2 and SK-HEP-1 cells in a dose- and time-dependent manner. Further molecular mechanistic investigation demonstrates that Huachansu significantly suppresses thymidylate synthase (TYMS), the enzyme which provides the sole de novo source of thymidylate for DNA synthesis. The inhibition of TYMS could lead to cell-cycle block and DNA damage of HCC cells. Furthermore, we identified that Huachansu markedly increased γ-H2AX expression, which indicated the presence of DNA damage. Moreover, we confirmed that transfection of cells with small interfering RNA specific to TYMS could increase the suppressive effects of Huachansu on the HCC cells proliferation. Quantitative RT-PCR analysis showed that Huachansu treatment had no effect on the transcription level of TYMS. Furthermore, proteasomal inhibitor MG132 could block TYMS inhibition induced by Huachansu, and concomitant administration of protein synthesis inhibitor cycloheximide (CHX) with Huachansu could further suppress the protein level of TYMS, indicating that Huachansu promotes proteasome-dependent degradation of TYMS in liver cancer cells. More importantly, the bioactive bufadienolides of Huachansu such as Bufalin, Bufotalin, Cinobufotalin, Desacetylcinobufagin, Arenobufagin, Telocinobufagin, and Resibufogenin could also significantly restrain the protein level of TYMS, revealing the material basis of inhibition of TYMS exposed to Huachansu. 5-fluorouracil (5-FU) is a TYMS inhibitor, we also evaluate the effects of the combined treatment of Huachansu with 5-FU, the results show that interactions between Huachansu and 5-FU are synergistic or antagonistic. Thus, in clinical, attention should be paid to the dosage of Huachansu in combination with 5-FU. ConclusionHuachansu inhibits the growth and induces DNA damage of human HCC cells through proteasome-dependent degradation of TYMS, bioactive bufadienolides are the material basis of down-regulation of TYMS induced by Huachansu.

Abstract LB005: Identification of novel targets for MYC-driven hepatocellular carcinoma via transomics

Abstract Hepatocellular carcinoma (HCC) is an aggressive tumor, and treatment options for patients with unresectable HCC are limited to targeted therapies and immunotherapy. The activation and dysregulation of MYC have been implicated in multiple cancers, including HCC, where approximately 30% of human HCC samples show MYC gene amplification. However, it is challenging to target MYC directly. Therefore, we applied a novel approach to circumvent targeting MYC directly by leveraging Pepper’s proprietary transomic analysis platform, COMPASS, to identify novel targets that are predicted to mimic the effect of turning MYC off. Specifically, COMPASS unlocks functional drivers of disease to identify novel drug targets. To study the role of MYC in tumor biology, we utilize an HCC cell line with tunable MYC expression. We generate genomic, transcriptomic, proteomic, and phosphoproteomic data from samples with MYC-on and MYC-off and compare via COMPASS to identify novel targets that mimic turning MYC off. The MYC-conditional HCC cell line (EC4) allows the regulation of MYC expression via the tetracycline regulatory (Tet-Off) system. Four omic datasets were collected from each sample: genomics (next-generation sequencing, NGS), transcriptomics (NGS), proteomics (mass spectrometry), and phosphoproteomics (mass spectrometry). We employed the COMPASS target prioritization algorithm to identify and rank novel targets that mimic turning MYC off. Targets were then filtered to select those with an available pharmacological tool compound (PTC). The PTCs were used to evaluate the targets in the Huh-7 xenograft model of HCC. All targets were kinases or related to kinase activity and pathways. All PTCs inhibited tumor growth from 18.1-78.3%. One multi-tyrosine kinase inhibitor resulted in maximum tumor growth inhibition, resulting in stasis of tumor growth and increased survival compared with control vehicle-treated mice. We have previously shown how the COMPASS transomics analysis approach can identify novel drug targets for drug resistant EGFRm NSCLC. The data presented here on MYC-driven HCC further validates this approach for novel target identification. Ongoing work will investigate novel targets using gene silencing, as PTCs were unavailable for many of these novel high-ranked targets identified in this study. Further validation studies are ongoing against other difficult-to-treat MYC-driven cancers to identify novel clinical targets and drug candidates to circumvent the MYC pathway. Citation Format: Simon P. Fricker, Christopher J. Nicholson, Samuel J. Roth, Arudhir Singh, Caitlin Brown, Jon Hu, Petronela Buiga, Vishnu P. Kanakaveti, Anja Deutzmann, Dean Felsher, Samantha D. Strasser. Identification of novel targets for MYC-driven hepatocellular carcinoma via transomics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB005.

Cyclovirobuxine D inhibits hepatocellular carcinoma growth by inducing ferroptosis of hepatocellular carcinoma cells

ObjectiveHepatocellular carcinoma (HCC) is one cancer with high death rates. Nowadays, there are no effective drugs to treat it. Cyclovirobuxine D (CVB-D) is the primary ingredient of the traditional Chinese medicine (TCM) Buxus microphylla. Here, we try to explore the impacts of CVB-D on human HCC cells and explain the potential mechanisms.MethodsHepG2 and Huh-7 cells were used for our experiments. The cell viability and half inhibitory concentration (IC50) were detected by MTT assays. The apoptosis ratio was examined by Annexin V-FITC/7AAD staining and flow cytometry (FCM). The Fe2+ content was examined by ferrous ion content assays. The malondialdehyde (MDA) content was evaluated by lipid peroxidation MDA assays. The reactive oxygen species (ROS) level was examined by the DCFH-DA probe. The expression of apoptotic markers (Bax and Bcl-2) and ferroptosis-related proteins (GPX4 and FSP1) was detected by western blotting. The in vivo curative effect of CVB was explored using xenograft models established in C-NKG mice.ResultsThe cell viability could be inhibited by CVB-D in HepG2 and Huh-7 cells. The IC50 value of CVB-D on HepG2 and Huh-7 cells are 91.19 and 96.29 µM at 48 h, and 65.60 and 72.80 µM at 72 h. FCM showed that the apoptosis rate was increased by CVB-D in HepG2 and Huh-7 cells. Next, ferrous ion content assays showed that the level of Fe2+ was increased by CVB-D in HepG2 and Huh-7 cells. Then, we found the level of MDA and ROS was increased by CVB-D. And the Fe2+ promotion by CVB-D could be reversed by Fer-1. Additionally, western blotting assays showed that the expression of GPX4 and FSP1 was inhibited by CVB-D in HepG2 and Huh-7 cells. Moreover, in vivo, CVB-D displayed excellent anticancer effects in HCC tumor-bearing C-NKG mice.ConclusionCVB-D suppresses the growth in HCC cells through ferroptosis.

Abstract 4283: NAMPT-enriched small extracellular vesicle promotes liver cancer via activation of SLC27A4-mediated glycolysis

Abstract Introduction: Tumor-derived small extracellular vesicles (sEV) act as a major mediator of the tumor microenvironment (TME) and are reported to regulate various metabolic pathways. Methods: Small extracellular vesicles (sEV) were collected from normal human hepatocyte and metastatic HCC cell lines using differential ultracentrifugation. Mass Spectrometry proteomic analysis was employed to identify NAMPT to be enriched in metastatic HCC-sEV. The glycolytic effect of NAMPT-sEV was analyzed by seahorse glycolytic assay. Result: Mass spectrometry protein analysis revealed nicotinamide phosphoribosyl transferase (NAMPT) to be upregulated in metastatic HCC-sEV. NAMPT is a rate-limiting enzyme essential for maintaining cellular level of nicotinamide dinucleotide (NAD+). However, the underlying pathway of sEV-NAMPT-induced metabolic consequence in HCC remains largely unknown. This study elucidated sEV-NAMPT’s carcinogenic role by establishing NAMPT-knockdown (NAMPT-KD) stable clone in metastatic HCC cell lines, which significantly hampered the promoting effect of HCC-sEV in glycolysis. sEV-mediated in vitro and in vivo tumor growth was also inhibited. Through sEV treatment, we found that sEV-NAMPT significantly elevate SLC27A4 in both transcription and protein level of recipient cells. Mechanistically, it is demonstrated that SLC27A4 expression was enhanced by NF-κB transcription factor, which is activated upon binding of sEV-NAMPT to toll-like receptor 4 (TLR4). SLC27A4 mainly function as a long-chain fatty acid transporter or acyl-CoA synthetase. Lipidomic and metabolomic analysis unveiled SLC27A4 to be positively correlated with intracellular triacylglycerol (TG) and dihydroxyacetone phosphate (DHAP) level. Elevation of TG aggravates lipolysis by hepatic lipase and promotes conversion of glycerol-3-P to DHAP, which is an intermediate metabolite that transit between lipid metabolism and glycolysis. This study uncovers a regulatory axis of sEV-NAMPT-mediated SLC27A4 in glycolysis, apart from conventional fatty acid-related metabolisms. Clinically, we explored the therapeutic potential of targeting sEV-NAMPT by inhibitor FK866. Treatment of NAMPT-inhibitor significantly hampered tumor growth in various HCC in vivo models, which suggested an alternative therapeutic strategy for HCC. Conclusion: NAMPT is enriched in metastatic HCC sEV. sEV-NAMPT regulates the promoting effect of HCC-sEV in glycolysis and oncogenesis. SLC27A4 function as the downstream target that promotes HCC progression via glycolysis. NAMPT inhibitor FK866 are proven to reduce in vitro and in vivo tumorigenic ability of metastatic HCC-sEV, which may serve as potential HCC treatment option. Citation Format: Lot Sum Cherlie Yeung, Tu Him ng, Judy Wai Ping Yam. NAMPT-enriched small extracellular vesicle promotes liver cancer via activation of SLC27A4-mediated glycolysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4283.

Abstract 2274: Genomic and transcriptomic analyses of chemical hepatocarcinogenesis aggravated by loss of oncoproteins in hepatocytes

Abstract Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death without effective treatment. Oncogenic drivers, including PTPN11/Shp2, Ikkβ kinase (IKK), c-Met and β-catenin, as well as tumor microenvironment as illustrated by a carcinogen or diethylnitrosamine (DEN)-treated models, have combined contribution to cancer progression that have distinct prevalence in human HCC progression. We previously found that disruption of Ras/Erk by Shp2 deletion combined with deletion of NF-κB unexpectedly dysregulated circadian clock genes which leads to further cancer progression. Except for this, limited reports investigated how various other oncogenic genes aberration would incorporate with DEN to induce HCC. Further, no reports investigated the dynamic evolution of transcriptomic aberration incorporating genetic changes and the differential functional pathways involved in DEN plus oncogene triggered-HCC progression. Thus, we here sought to investigate the context-dependent contribution of PTPN11/Shp2, IKK, c-Met and β-catenin to HCC using hepatocyte-specific deletion models (SKO, IKO, MKO, BKO) combined with DEN treatment. Exome sequencing and RNAseq were used to identify dynamic changes of the genomic and transcriptomic variations of HCC development under the influence of both genetic deletion and DEN-treatment. We found that upregulated epithelial-mesenchymal transition (EMT), cancer metastasis/migration and downregulated fatty-acid and cholesterol metabolism were highly involved across models. Macrophages together with genes including Spi1, Clec7a, and microRNA networks including miR-122 and miR-155 etc. were also deregulated. Specifically, upregulated IL2-STAT5 signaling in DEN-SKO liver tissues, upregulated myogenesis, KRAS signaling and EMT as well as apoptosis in DEN-MKO, downregulated xenobiotic metabolism and bile acid metabolism in DEN-IKO and -BKO were identified to be distinct to oncogenic deletion in relation with HCC development. Citation Format: Xinyi Wang, Jiemeng Zhang, Yingluo Liu, Shuo Zhang, Yan Liang, Min Zong, Xiaoxue Lin, Michael Karin, Gensheng Feng. Genomic and transcriptomic analyses of chemical hepatocarcinogenesis aggravated by loss of oncoproteins in hepatocytes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2274.

Abstract 7065: AMBRA1 coordinates mitochondrial function to regulate cancer stemness and tumorigenesis in hepatocellular carcinoma

Abstract Hepatocellular carcinoma (HCC) is a prevalent and aggressive cancer, with emerging evidence highlighting the role of cancer stem cells (CSCs) in its progression. AMBRA1 has been implicated to exert both tumor-promoting and tumor-suppressive roles through regulating cell cycle and mitophagy in various solid tumors. However, the functional roles of AMBRA1 in modulating cancer stemness and tumorigenesis in HCC remain elusive. Initial analysis of The Cancer Genome Atlas data revealed a significant inverse correlation between AMBRA1 expression and stemness indices (TSS) in HCC patients, with low AMBRA1 levels associated with an upregulated oxidative phosphorylation (OXPHOS) gene signature. To elucidate the functional consequences of AMBRA1 modulation in liver tumor development and stemness maintenance, we exploited both hydrodynamic mouse models and human HCC cell lines. Our findings indicate that hepatic AMBRA1 deletion enhances cancer stemness and tumorigenesis both in vivo and in vitro. Moreover, HCC cells with reduced AMBRA1 expression demonstrated heightened mitochondrial activity, characterized by increased oxygen consumption, respiration, mitochondrial membrane potential, and intracellular ATP levels. Apart from OXPHOS, we also observed a concomitant up-regulation and enrichment of MYC targets in TSS-high and AMBRA1-low HCC patients, pointing towards a deregulated c-MYC signaling to promote cancer stemness under AMBRA1 regulation in HCC. Collectively, our results demonstrate that AMBRA1 loss enhances mitochondrial function to support hepatic tumorigenesis in HCC. Citation Format: Yan Liu, Yunong Xie, Yimiao He, Stephanie Ma, Man Tong. AMBRA1 coordinates mitochondrial function to regulate cancer stemness and tumorigenesis in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7065.

Abstract 630: The role of AKT pathway in β-catenin mutated hepatocellular carcinoma

Abstract The Wnt/β-catenin and PI3K/AKT pathways are pivotal contributors to the development of the malignant phenotype in cancer. The activated Wnt/β-catenin pathway synergizes with various signaling cascades to propel HCC formation, operating through its downstream effectors. It has been well-established that the mammalian target of rapamycin complex 2 (mTORC2) serves as an upstream regulator of AKT, orchestrating the phosphorylation and activation of AKT. Once activated, AKT phosphorylates and inhibits canonical downstream targets like forkhead box O protein (FOXO) and tuberous sclerosis complex 2 (TSC2). Studies indicated that AKT-mediated phosphorylation of TSC2 activates mTORC1, subsequently suppressing autophagy. However, there are limited data exist on the interplay between Wnt/β-catenin and AKT pathways in HCC. In this study, we sought to explore the role of the AKT pathway in β-catenin activated HCC tumors. Sleeping beauty-mediated hydrodynamic transfection was used to overexpress constitutively active forms of β-catenin (N90-β-catenin) and c-MET in the livers of mice to establish the HCC model (c-Met/β-catenin model). Notably, the knockout of Rictor, a component of the mTORC2 complex, significantly impeded tumor growth, underscoring the pivotal role of AKT in c-Met/β-catenin tumor development. AKT1 and AKT2 are the two main isoforms expressed in the liver. We determined that both AKT1 and AKT2 isoforms are critical for c-Met/β-catenin tumor growth. Intriguingly, simultaneous knockout of Rictor and activation of mTORC1 in the c-Met/β-catenin model resulted in delayed tumor growth, indicating that mTORC1 is not the sole downstream determinant of AKT signaling during c-Met/β-Catenin tumor development. Furthermore, overexpression of the activated FOXO1 (FOXO1AAA) significantly delayed the tumor growth, which highlighted the importance of FOXO1. Given the limited understanding of FOXO1 in HCC, we extended our investigation on FOXO1 to human HCC cell lines. Overexpression of FOXO1AAA notably delayed tumor growth in vitro. RNAseq analysis of FOXO1AAA-overexpressed human HCC cell lines revealed a significant upregulation of "metabolic pathways", suggesting metabolic reprogramming post FOXO1 activation. This study, for the first time, unveils the role of the AKT pathway in β-catenin-mutated HCC growth and highlights the potential therapeutic value of targeting the AKT pathway in patients with β-catenin-mutated HCC. Citation Format: Xue Wang, Xin Chen. The role of AKT pathway in β-catenin mutated hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 630.

Abstract 2370: Revitalizing anti-tumor immunity through PLT012 monoclonal antibody, targeting CD36 for metabolic rewiring in the tumor microenvironment

Abstract The accumulation of lipid metabolic products in the TME has been extensively documented to exacerbate cancer malignancy by suppressing anti-tumor immunity. This phenomenon is characterized by the induction of immunosuppressive features in various immune cells and the development of exhausted phenotypes in T cells, creating formidable obstacles for effective immunotherapies. Notably, CD36, a fatty acid transporter, has been identified as up-regulated in both malignant cells and various tumor-associated immune cells, including regulatory T cells, tumor-associated macrophages, and CD8+ T cells. This upregulation serves to adjust the metabolic preferences of these cells, enabling adaptation to the lipid-enriched TME. CD36-mediated adaptation not only instigates alterations in metabolic regulations but also significantly influences immune cell properties, contributing to the establishment of an immunosuppressive TME. Consequently, it has been proposed that inhibiting CD36-mediated fatty acid uptake could strategically reshape the host's anti-tumor immunity within the TME, resulting in the reduction of tumor-infiltrating regulatory T cells and the restoration of both survival and functionality in CD8 T cells. These findings underscore the therapeutic potential of anti-CD36 antibodies as a targeted approach to mitigate the immunosuppressive milieu within the TME. Hence, PLT012, a humanized anti-CD36 antibody, was developed via phage display, followed by affinity maturation and developability optimization, and possesses cross-reactivity among species, including murine, non-human primates, and human. Through CryoEM-based structural analysis, we found that PLT012 recognizes the lipid binding domain of CD36 without interfering with the TSP-1 binding site. Moreover, administration of PLT012 significantly reduced oxLDL-mediated M2 macrophage polarization and fatty acid uptake in CD8+ TILs. Notably, HCC-bearing mice treated with PLT012 exhibited a significant reduction in tumor growth with an increased CD8/Treg ratio and CD8 effector functions, consistent with the ex vivo observations of PLT012 treatments in human HCC samples. In addition to murine studies, PLT012 also demonstrated excellent tolerability in NHP studies without any adverse effects. Ongoing studies in translational medicine will further bridge our findings and proposed mechanism of action with clinical observations, highlighting the potential therapeutic outcome in HCC patients particularly. Taken together, these results reveal that blocking CD36-mediated metabolic alterations in Treg and CD8+ TILs with PLT012 treatment can elicit robust tumor growth inhibition and shift the immunosuppressive nature within the TME toward an immunosupportive one. This study further provides the pillar for harnessing immunometabolic targeting in cancer immunotherapy. Citation Format: Yi-Ru Yu, Sheue-Fen Tzeng, Huey-Wen Hsiao, Jaeoh Park, Lana Kandalaft, Yun-Han Lin, Chin-Hsien Tsai, Ping-Chih Ho. Revitalizing anti-tumor immunity through PLT012 monoclonal antibody, targeting CD36 for metabolic rewiring in the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2370.

Steroid receptor coactivator 1 promotes human hepatocellular carcinoma invasiveness through enhancing MMP-9.

SRC-1 functions as a transcriptional coactivator for steroid receptors and various transcriptional factors. Notably, SRC-1 has been implicated in oncogenic roles in multiple cancers, including breast cancer and prostate cancer. Previous investigations from our laboratory have established the high expression of SRC-1 in human HCC specimens, where it accelerates HCC progression by enhancing Wnt/beta-catenin signalling. In this study, we uncover a previously unknown role of SRC-1 in HCC metastasis. Our findings reveal that SRC-1 promotes HCC metastasis through the augmentation of MMP-9 expression. The knockdown of SRC-1 effectively mitigated HCC cell metastasis both invitro and invivo by suppressing MMP-9 expression. Furthermore, we observed a positive correlation between SRC-1 mRNA levels and MMP-9 mRNA levels in limited and larger cohorts of HCC specimens from GEO database. Mechanistically, SRC-1 operates as a coactivator for NF-κB and AP-1, enhancing MMP-9 promoter activity in HCC cells. Higher levels of SRC-1 and MMP-9 expression are associated with worse overall survival in HCC patients. Treatment with Bufalin, known to inhibit SRC-1 expression, significantly decreased MMP-9 expression and inhibited HCC metastasis in both invitro and invivo settings. Our results demonstrated the pivotal role of SRC-1 as a critical modulator in HCC metastasis, presenting a potential therapeutic target for HCC intervention.

Hepatocellular carcinoma cells downregulate NADH:Ubiquinone Oxidoreductase Subunit B3 to maintain reactive oxygen species homeostasis.

HCC is a leading cause of cancer-related death. The role of reactive oxygen species (ROS) in HCC remains elusive. Since a primary ROS source is the mitochondrial electron transport chain complex Ι and the NADH:ubiquinone Oxidoreductase Subunit B3 (NDUFB3), a complex I subunit, is critical for complex I assembly and regulates the associated ROS production, we hypothesize that some HCCs progress by hijacking NDUFB3 to maintain ROS homeostasis. NDUFB3 in human HCC lines was either knocked down or overexpressed. The cells were then analyzed in vitro for proliferation, migration, invasiveness, colony formation, complex I activity, ROS production, oxygen consumption, apoptosis, and cell cycle. In addition, the in vivo growth of the cells was evaluated in nude mice. Moreover, the role of ROS in the NDUFB3-mediated changes in the HCC lines was determined using cellular and mitochondrion-targeted ROS scavengers. HCC tissues showed reduced NDUFB3 protein expression compared to adjacent healthy tissues. In addition, NDUFB3 knockdown promoted, while its overexpression suppressed, HCC cells' growth, migration, and invasiveness. Moreover, NDUFB3 knockdown significantly decreased, whereas its overexpression increased complex I activity. Further studies revealed that NDUFB3 overexpression elevated mitochondrial ROS production, causing cell apoptosis, as manifested by the enhanced expressions of proapoptotic molecules and the suppressed expression of the antiapoptotic molecule B cell lymphoma 2. Finally, our data demonstrated that the apoptosis was due to the activation of the c-Jun N-terminal kinase (JNK) signaling pathway and cell cycle arrest at G0/G1 phase. Because ROS plays essential roles in many biological processes, such as aging and cancers, our findings suggest that NDFUB3 can be targeted for treating HCC and other human diseases.

Studies on Differentially Expressed Genes of Tetrastigma hemsleyanum and Its Antitumor Activity

Objective: To analyze highly expressed genes in Tetrastigma hemsleyanum roots and the in vitro antitumor effects of extracts from different parts of this plant. Methods: The expression profiles of the roots, stems, and leaves of T hemsleyanum were analyzed via high-throughput sequencing technology with the Illumina Genome Analyzer platform. Then, gene ontology (GO) functional and pathway enrichment analyses of the significantly differentially expressed genes were performed. The inhibition rates of the extracts from different plant parts were determined through the CCK-8 method. Results: Genes related to catalytic activity and cytochrome P450 were upregulated in roots compared with leaves. The genes that we screened that were expressed at high levels in the roots may play an important role in the accumulation of active ingredients. GO functional enrichment analysis revealed that there were substantial differences in genes related to metabolic processes in roots compared with those in stems, and KEGG analysis revealed significant differences in genes related to the zeatin biosynthesis and diterpenoid biosynthesis pathways. Moreover, the expression of genes related to catalytic activity, ion binding, and hydrolase activity differed significantly between the roots and leaves, and KEGG analysis revealed significant differences in the expression of genes related to terpenoid biosynthesis and flavonoid biosynthesis pathways. Quantitative PCR indicated that Thhg was highly expressed in roots. The total triterpene content was also high in the tissue. The CCK-8 assays showed that the root ethanol extract had the highest antitumor activity. Conclusion: The genes we screened that were expressed at high levels in the roots may play an important role in the accumulation of active ingredients. Importantly, stem and leaf ethanol extracts also showed certain antitumor effects on human HCC Huh-7 and Hep3B cells in vitro and may also have medicinal value.

USP40 promotes hepatocellular carcinoma cell proliferation, migration and stemness by deubiquitinating and stabilizing Claudin1

BackgroundHepatocellular carcinoma (HCC) is a prevalent malignant tumor that poses a major threat to people’s lives and health. Previous studies have found that multiple deubiquitinating enzymes are involved in the pathogenesis of HCC. The purpose of this work was to elucidate the function and mechanism of the deubiquitinating enzyme USP40 in HCC progression.MethodsThe expression of USP40 in human HCC tissues and HCC cell lines was investigated using RT-qPCR, western blotting and immunohistochemistry (IHC). Both in vitro and in vivo experiments were conducted to determine the crucial role of USP40 in HCC progression. The interaction between USP40 and Claudin1 was identified by immunofluorescence, co-immunoprecipitation and ubiquitination assays.ResultsWe discovered that USP40 is elevated in HCC tissues and predicts poor prognosis in HCC patients. USP40 knockdown inhibits HCC cell proliferation, migration and stemness, whereas USP40 overexpression shows the opposite impact. Furthermore, we confirmed that Claudin1 is a downstream gene of USP40. Mechanistically, USP40 interacts with Claudin1 and inhibits its polyubiquitination to stabilize Claudin1 protein.ConclusionsOur study reveals that USP40 enhances HCC malignant development by deubiquitinating and stabilizing Claudin1, suggesting that targeting USP40 may be a novel approach for HCC therapy.

Downregulation of Roundabout guidance receptor 2 suppresses hepatocellular carcinoma progression by interacting with Y-box binding protein 1

Roundabout guidance receptor 2 (Robo2) is closely related to malignant tumors such as pancreatic cancer and liver fibrosis, but there is no relevant research on the role of Robo2 in HCC. The study will further explore the function and mechanism of Robo2 and its downstream target genes in HCC. Firstly, Robo2 protein levels in human HCC tissues and paired adjacent normal liver tissues were detected. Then we established HepG2 and Huh7 hepatoma cell lines with knock-down Robo2 by transfection with lentiviral vectors, and examined the occurrence of EMT, proliferation and apoptosis abilities in HCC cells by western blot, flow cytometry, wound healing assay and TUNEL staining. Then we verified the interaction between Robo2 and its target gene by Co-IP and immunofluorescence co-staining, and further explored the mechanism of Robo2 and YB-1 by rescue study. The protein expression level of Robo2 in HCC was considerably higher than that in the normal liver tissues. After successfully constructing hepatoma cells with knock-down Robo2, it was confirmed that down-regulated Robo2 suppressed EMT and proliferation of hepatoma cells, and accelerated the cell apoptosis. High-throughput sequencing and validation experiments verified that YB-1 was the downstream target gene of Robo2, and over-expression of YB-1 could reverse the apoptosis induced by Robo2 down-regulation and its inhibitory effect on EMT and proliferation. Robo2 deficiency inhibits EMT and proliferation of hepatoma cells and augments the cell apoptosis by regulating YB-1, thus inhibits the occurrence of HCC and provides a new strategy for the treatment of HCC.

Targeting the SphK1/S1P/PFKFB3 axis suppresses hepatocellular carcinoma progression by disrupting glycolytic energy supply that drives tumor angiogenesis

BackgroundHepatocellular carcinoma (HCC) remains a leading life-threatening health challenge worldwide, with pressing needs for novel therapeutic strategies. Sphingosine kinase 1 (SphK1), a well-established pro-cancer enzyme, is aberrantly overexpressed in a multitude of malignancies, including HCC. Our previous research has shown that genetic ablation of Sphk1 mitigates HCC progression in mice. Therefore, the development of PF-543, a highly selective SphK1 inhibitor, opens a new avenue for HCC treatment. However, the anti-cancer efficacy of PF-543 has not yet been investigated in primary cancer models in vivo, thereby limiting its further translation.MethodsBuilding upon the identification of the active form of SphK1 as a viable therapeutic target in human HCC specimens, we assessed the capacity of PF-543 in suppressing tumor progression using a diethylnitrosamine-induced mouse model of primary HCC. We further delineated its underlying mechanisms in both HCC and endothelial cells. Key findings were validated in Sphk1 knockout mice and lentiviral-mediated SphK1 knockdown cells.ResultsSphK1 activity was found to be elevated in human HCC tissues. Administration of PF-543 effectively abrogated hepatic SphK1 activity and significantly suppressed HCC progression in diethylnitrosamine-treated mice. The primary mechanism of action was through the inhibition of tumor neovascularization, as PF-543 disrupted endothelial cell angiogenesis even in a pro-angiogenic milieu. Mechanistically, PF-543 induced proteasomal degradation of the critical glycolytic enzyme 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3, thus restricting the energy supply essential for tumor angiogenesis. These effects of PF-543 could be reversed upon S1P supplementation in an S1P receptor-dependent manner.ConclusionsThis study provides the first in vivo evidence supporting the potential of PF-543 as an effective anti-HCC agent. It also uncovers previously undescribed links between the pro-cancer, pro-angiogenic and pro-glycolytic roles of the SphK1/S1P/S1P receptor axis. Importantly, unlike conventional anti-HCC drugs that target individual pro-angiogenic drivers, PF-543 impairs the PFKFB3-dictated glycolytic energy engine that fuels tumor angiogenesis, representing a novel and potentially safer therapeutic strategy for HCC.