Ablation of secreted phosphoprotein-1 in hepatocytes increases fatty acid oxidation and ameliorates alcohol-associated liver disease.

BACKGROUND: Previously, we demonstrated that Spp1-/- mice exhibit a greater susceptibility to alcohol-induced liver injury than wild-type (WT) mice. Notably, alcohol triggers the expression of osteopontin (encoded by SPP1) in hepatocytes. However, the specific role of hepatocyte-derived SPP1 in either mitigating or exacerbating alcohol-associated liver disease (AALD) has yet to be elucidated. We hypothesized that hepatocyte-derived SPP1 plays a role in AALD by modulating the regulation of steatosis. METHODS: We analyzed hepatic SPP1 expression using four publicly available datasets from patients with alcoholic hepatitis (AH). Additionally, we examined SPP1 expression in the livers of WT mice subjected to either a control or ethanol Lieber-DeCarli (LDC) diet for 6 weeks. We compared the relationship between SPP1 expression and significantly dysregulated genes in AH with controls using correlation and enrichment analyses. To investigate the specific impact of hepatocyte-derived SPP1, we generated hepatocyte-specific Spp1 knock-out (Spp1ΔHep) mice and subjected them to either a control or ethanol Lieber-DeCarli diet for 6 weeks. RESULTS: Alcohol induced hepatic SPP1 expression in both humans and mice. Our analysis, focusing on genes correlated with SPP1, revealed an enrichment of fatty acid oxidation (FAO) in three datasets, and peroxisome proliferator-activated receptor signaling in one dataset. Notably, FAO genes correlating with SPP1 were downregulated in patients with AH. Ethanol-fed WT mice exhibited higher serum-free fatty acids (FFAs), adipose tissue lipolysis, and hepatic fatty acid (FA) transporters. In contrast, ethanol-fed Spp1ΔHep mice displayed lower liver triglycerides, FFAs, and serum alanine transaminase and greater FAO gene expression than WT mice, indicating a protective effect against AALD. Primary hepatocytes from Spp1∆Hep mice exhibited heightened expression of genes encoding proteins involved in FAO. CONCLUSIONS: Alcohol induces the expression of SPP1 in hepatocytes, leading to impaired FAO and contributing to the development of AALD.

Autologous Gastrointestinal Graft-vs-Host Disease in a Patient With Multiple Myeloma and Hematopoietic Stem Cell Transplantation.

Graft-vs-host disease (GVHD) of the gastrointestinal (GI) tract is notably a serious complication of allogeneic hematopoietic stem cell transplant (HSCT). However, GI GVHD has rarely been reported in autologous HSCT, and the pathophysiology remains unclear. Diagnosing GVHD after autologous HSCT requires a high level of clinical suspicion, given its nonspecific clinical presentation and endoscopic findings necessitating a histological diagnosis for confirmation. We present a case of autologous GVHD involving the GI tract in a patient with multiple myeloma who responded well to corticosteroids, highlighting the importance of early identification of this rare entity to initiate therapy and improve outcomes.

Hepatocellular Carcinoma Epigenetic Patterns Correspond to Differences in Ethnoracial Status and Treatment Response in a Single-Center Retrospective Study.

PURPOSE: To correlate epigenetic patterns with ethnoracial status and locoregional therapy (LRT) response in patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: DNA and RNA were extracted from 47 distinct formalin-fixed paraffin-embedded tumor samples from 42 patients with HCC (n = 14 Black, n = 19 White, n = 9 Hispanic). LRT response was determined using computed tomography (CT) or magnetic resonance (MR) imaging 3 months posttreatment of 35 tumors (n = 22 complete response, n = 13 retreatment candidates). RNA expression and DNA methylation were used to stratify patients by ethnoracial status and treatment response using partial least-squares discriminant analysis (PLS-DA). Results were validated using hierarchical clustering. Ingenuity pathway analysis was performed to identify upstream regulators and pathways. RESULTS: PLS-DA identified 100 genes and 12 methylated regions that differentiated tumors from Black from White/Hispanic patients. Hierarchical clustering clustered samples with the top 16 genes or the top 5 methylation regions. Dysregulated pathways included adrenomedullin pathway (P = .030), EIF2 signaling (P = .007), and several metabolic pathways. AGTR1 (log2fold = 1.59) and GSTM3 (log2fold = 2.53) represented potential differentially expressed therapeutic targets. PLS-DA identified 100 genes and 150 methylation regions that differentiated between complete responders and retreatment candidates. Hierarchical clustering clustered samples with the top 30 genes or the top 13 methylation regions. Dysregulated pathways included metabolic and DNA repair-related pathways. ASAP2 (log2fold = 0.29) and RAD50 (log2fold = 0.22) represented potential differentially expressed therapeutic targets. CONCLUSIONS: Variation in gene expression and DNA methylation patterns in patients with HCC corresponded to ethnoracial status and LRT response. These initial results suggest tumor profiling has the potential to close ethnoracial disparities and improve treatment stratification.

Overexpression of HMGB1 in hepatocytes accelerates PTEN inactivation-induced liver cancer.

BACKGROUND: Liver cancer is increasing due to the rise in metabolic dysfunction-associated steatohepatitis (MASH). High-mobility group box-1 (HMGB1) is involved in the pathogenesis of chronic liver disease, but its role in MASH-associated liver cancer is unknown. We hypothesized that an increase in hepatocyte-derived HMGB1 in a mouse model of inactivation of PTEN that causes MASH could promote MASH-induced tumorigenesis. METHODS: We analyzed publicly available transcriptomics datasets, and to explore the effect of overexpressing HMGB1 in cancer progression, we injected 1.5-month-old Pten∆Hep mice with adeno-associated virus serotype-8 (AAV8) vectors to overexpress HMGB1-EGFP or EGFP, and sacrificed them at 3, 9 and 11 months of age. RESULTS: We found that HMGB1 mRNA increases in human MASH and MASH-induced hepatocellular carcinoma (MASH-HCC) compared to healthy livers. Male and female Pten∆Hep mice overexpressing HMGB1 showed accelerated liver tumor development at 9 and 11 months, respectively, with increased tumor size and volume, compared to control Pten∆Hep mice. Moreover, Pten∆Hep mice overexpressing HMGB1, had increased incidence of mixed HCC-intrahepatic cholangiocarcinoma (iCCA). All iCCAs were positive for nuclear YAP and SOX9. Male Pten∆Hep mice overexpressing HMGB1 showed increased cell proliferation and F4/80+ cells at 3 and 9 months. CONCLUSION: Overexpression of HMGB1 in hepatocytes accelerates liver tumorigenesis in Pten∆Hep mice, enhancing cell proliferation and F4/80+ cells to drive MASH-induced liver cancer.

Intracranial hematolymphoid malignancies: A case series with molecular characterization.

OBJECTIVE: Central nervous system (CNS) manifestations of hematologic malignancies are uncommon and often have a poor prognosis. As hematologic neoplasms are typically chemotherapy- and radiotherapy-sensitive, surgical resection is usually not indicated; thus, opportunities for in-depth characterization of CNS hematologic tumors are limited. Here, we report four cases of rare intracranial hematologic tumors requiring surgical intervention, allowing for histopathologic and genomic characterization. METHODS: The clinical course, genetic perturbations, and histopathological features are described for a case of 1) primary marginal zone B-cell lymphoma of the dura as well as cases of brain metastases of 2) cutaneous T-cell lymphoma, 3) acute myeloid leukemia/myeloid sarcoma, and 4) multiple myeloma. Targeted DNA sequencing, fluorescence in situ hybridization, cytogenetic analysis, flow cytometry and immunohistochemical staining were used to assess the lesions. RESULT: Molecular and histopathological characterizations of four unusual presentations of hematolymphoid diseases involving the CNS are presented. Genetic abnormalities were identified in each lesion, including chromosomal aberrations and single nucleotide variants resulting in missense or nonsense mutations in oncogenes. CONCLUSIONS: Our case series provides insight into unique pathological phenotypes of hematologic neoplasms with atypical CNS involvement. We offer targets for future studies by identifying potentially pathogenic genetic variants in these lesions, as the full implications of the novel molecular abnormalities described remain unclear.

Phenylpropionic acid produced by gut microbiota alleviates acetaminophen-induced hepatotoxicity.

The gut microbiota affects hepatic drug metabolism. However, gut microbial factors modulating hepatic drug metabolism are largely unknown. In this study, using a mouse model of acetaminophen (APAP)-induced hepatotoxicity, we identified a gut bacterial metabolite that controls the hepatic expression of CYP2E1 that catalyzes the conversion of APAP to a reactive, toxic metabolite. By comparing C57BL/6 substrain mice from two different vendors, Jackson (6J) and Taconic (6N), which are genetically similar but harbor different gut microbiotas, we established that the differences in the gut microbiotas result in differential susceptibility to APAP-induced hepatotoxicity. 6J mice exhibited lower susceptibility to APAP-induced hepatotoxicity than 6N mice, and such phenotypic difference was recapitulated in germ-free mice by microbiota transplantation. Comparative untargeted metabolomic analysis of portal vein sera and liver tissues between conventional and conventionalized 6J and 6N mice led to the identification of phenylpropionic acid (PPA), the levels of which were higher in 6J mice. PPA supplementation alleviated APAP-induced hepatotoxicity in 6N mice by lowering hepatic CYP2E1 levels. Moreover, PPA supplementation also reduced carbon tetrachloride-induced liver injury mediated by CYP2E1. Our data showed that previously known PPA biosynthetic pathway is responsible for PPA production. Surprisingly, while PPA in 6N mouse cecum contents is almost undetectable, 6N cecal microbiota produces PPA as well as 6J cecal microbiota in vitro, suggesting that PPA production in the 6N gut microbiota is suppressed in vivo. However, previously known gut bacteria harboring the PPA biosynthetic pathway were not detected in either 6J or 6N microbiota, suggesting the presence of as-yet-unidentified PPA-producing gut microbes. Collectively, our study reveals a novel biological function of the gut bacterial metabolite PPA in the gut-liver axis and presents a critical basis for investigating PPA as a modulator of CYP2E1-mediated liver injury and metabolic diseases.

Macrophage-derived Osteopontin (SPP1) Protects From Nonalcoholic Steatohepatitis.

BACKGROUND & AIMS: Nonalcoholic steatohepatitis (NASH) is characterized by steatosis, lobular inflammation, hepatocyte ballooning degeneration, and fibrosis, all of which increase the risk of progression to end-stage liver disease. Osteopontin (OPN, SPP1) plays an important role in macrophage (MF) biology, but whether MF-derived OPN affects NASH progression is unknown. METHODS: We analyzed publicly available transcriptomic datasets from patients with NASH, and used mice with conditional overexpression or ablation of Spp1 in myeloid cells and liver MFs, and fed them a high-fat, fructose, and cholesterol diet mimicking the Western diet, to induce NASH. RESULTS: This study demonstrated that MFs with high expression of SPP1 are enriched in patients and mice with nonalcoholic fatty liver disease (NAFLD), and show metabolic but not pro-inflammatory properties. Conditional knockin of Spp1 in myeloid cells (Spp1KI Mye) or in hepatic macrophages (Spp1KI LvMF) conferred protection, whereas conditional knockout of Spp1 in myeloid cells (Spp1ΔMye) worsened NASH. The protective effect was mediated by induction of arginase-2 (ARG2), which enhanced fatty acid oxidation (FAO) in hepatocytes. Induction of ARG2 stemmed from enhanced production of oncostatin-M (OSM) in MFs from Spp1KI Mye mice. OSM activated STAT3 signaling, which upregulated ARG2. In addition to hepatic effects, Spp1KI Mye also protected through sex-specific extrahepatic mechanisms. CONCLUSION: MF-derived OPN protects from NASH, by upregulating OSM, which increases ARG2 through STAT3 signaling. Further, the ARG2-mediated increase in FAO reduces steatosis. Therefore, enhancing the OPN-OSM-ARG2 crosstalk between MFs and hepatocytes may be beneficial for patients with NASH.

CAR-T Therapies in Solid Tumors: Opportunities and Challenges.

PURPOSE OF REVIEW: This review will discuss the challenges facing chimeric antigen receptor (CAR)-T cell application for solid tumors and opportunities to overcome these obstacles. In addition, this review will examine therapies that are in development for pediatric solid tumors. RECENT FINDINGS: The similar success of CAR-T cell treatment for hematological malignancies has not been observed in solid tumors because of the hostile tumor microenvironment and tumor heterogeneity. Most strategies developed to combat these limitations emphasize combinatorial techniques that still require further testing. Preliminary results of multiple clinical trials, including GD2- and HER2-CAR-T cells, are encouraging but must be reproduced and validated on a larger scale. CAR-T cell application in solid tumors remains challenging, and most research is in development. Several clinical trials are ongoing for pediatric solid tumors. Early results are promising but demonstrate the need for CAR-T cell modification to prevent tumor recurrence.

Splicing factor SRSF1 deficiency in the liver triggers NASH-like pathology and cell death.

Regulation of RNA processing contributes profoundly to tissue development and physiology. Here, we report that serine-arginine-rich splicing factor 1 (SRSF1) is essential for hepatocyte function and survival. Although SRSF1 is mainly known for its many roles in mRNA metabolism, it is also crucial for maintaining genome stability. We show that acute liver damage in the setting of targeted SRSF1 deletion in mice is associated with the excessive formation of deleterious RNA-DNA hybrids (R-loops), which induce DNA damage. Combining hepatocyte-specific transcriptome, proteome, and RNA binding analyses, we demonstrate that widespread genotoxic stress following SRSF1 depletion results in global inhibition of mRNA transcription and protein synthesis, leading to impaired metabolism and trafficking of lipids. Lipid accumulation in SRSF1-deficient hepatocytes is followed by necroptotic cell death, inflammation, and fibrosis, resulting in NASH-like liver pathology. Importantly, SRSF1-depleted human liver cancer cells recapitulate this pathogenesis, illustrating a conserved and fundamental role for SRSF1 in preserving genome integrity and tissue homeostasis. Thus, our study uncovers how the accumulation of detrimental R-loops impedes hepatocellular gene expression, triggering metabolic derangements and liver damage.

CAR T-cells to treat brain tumors.

Tremendous success using CAR T therapy in hematological malignancies has garnered significant interest in developing such treatments for solid tumors, including brain tumors. This success, however, has yet to be mirrored in solid organ neoplasms. CAR T function has shown limited efficacy against brain tumors due to several factors including the immunosuppressive tumor microenvironment, blood-brain barrier, and tumor-antigen heterogeneity. Despite these considerations, CAR T-cell therapy has the potential to be implemented as a treatment modality for brain tumors. Here, we review adult and pediatric brain tumors, including glioblastoma, diffuse midline gliomas, and medulloblastomas that continue to portend a grim prognosis. We describe insights gained from different preclinical models using CAR T therapy against various brain tumors and results gathered from ongoing clinical trials. Furthermore, we outline the challenges limiting CAR T therapy success against brain tumors and summarize advancements made to overcome these obstacles.

Hepatocyte PPARγ contributes to the progression of non-alcoholic steatohepatitis in male and female obese mice.

Non-alcoholic steatohepatitis (NASH) is associated with obesity and increased expression of hepatic peroxisome proliferator-activated receptor γ (PPARγ). However, the relevance of hepatocyte PPARγ in NASH associated with obesity is still poorly understood. In this study, hepatocyte PPARγ was knocked out (PpargΔHep) in male and female mice after the development of high-fat diet-induced obesity. The diet-induced obese mice were then maintained on their original diet or switched to a high fat, cholesterol, and fructose (HFCF) diet to induce NASH. Hepatic PPARγ expression was mostly derived from hepatocytes and increased by high fat diets. PpargΔHep reduced HFCF-induced NASH progression without altering steatosis, reduced the expression of key genes involved in hepatic fibrosis in HFCF-fed male and female mice, and decreased the area of collagen-stained fibrosis in the liver of HFCF-fed male mice. Moreover, transcriptomic and metabolomic data suggested that HFCF-diet regulated hepatic amino acid metabolism in a hepatocyte PPARγ-dependent manner. PpargΔHep increased betaine-homocysteine s-methyltransferase expression and reduced homocysteine levels in HFCF-fed male mice. In addition, in a cohort of 102 obese patients undergoing bariatric surgery with liver biopsies, 16 cases were scored with NASH and were associated with increased insulin resistance and hepatic PPARγ expression. Our study shows that hepatocyte PPARγ expression is associated with NASH in mice and humans. In male mice, hepatocyte PPARγ negatively regulates methionine metabolism and contributes to the progression of fibrosis.

The basis and design for time-restricted eating compared with daily calorie restriction for weight loss and colorectal cancer risk reduction trial (TRE-CRC trial).

OBJECTIVE: Approximately 42% of American adults are living with obesity, increasing their risk of colorectal cancer (CRC). Efficacious approaches to prevent and treat obesity may reduce CRC incidence. Daily calorie restriction (Cal-R) is the most common approach to treating obesity, yet clinically meaningful weight loss is elusive owing to waning adherence. Time-restricted eating (TRE) consists of consuming foods within a specified time frame, creating a natural calorie deficit. TRE in animals shows cancer protective effects. In humans, TRE is safe and acceptable among adults with obesity, producing ~3% to 5% weight loss and reductions in oxidative stress and insulin resistance. However, TRE has not been tested rigorously for CRC preventive effects. METHODS: The authors describe a 12-month randomized controlled trial of 8-hour TRE (ad libitum 12 PM-8 PM), Cal-R (25% restriction daily), or Control among 255 adults at increased risk for CRC and with obesity. RESULTS: Effects on the following will be examined: 1) body weight, body composition, and adherence; 2) circulating metabolic, inflammation, and oxidative stress biomarkers; 3) colonic mucosal gene expression profiles and tissue microenvironment; and 4) maintenance of benefits on body weight/composition and CRC risk markers. CONCLUSIONS: This study will examine efficacious lifestyle strategies to treat obesity and reduce CRC risk among individuals with obesity.

Immunoglobulin G4 associated autoimmune cholangitis and pancreatitis following the administration of nivolumab: A case report.

BACKGROUND: Immune checkpoint inhibitors have significantly improved survivals for an increasing range of malignancies but at the cost of several immune-related adverse events, the management of which can be challenging due to its mimicry of other autoimmune related disorders such as immunoglobulin G4 (IgG4) related disease when the pancreaticobiliary system is affected. Nivolumab, an IgG4 monoclonal antibody, has been associated with cholangitis and pancreatitis, however its association with IgG4 related disease has not been reported to date. CASE SUMMARY: We present a case of immune-related pancreatitis and cholangiopathy in a patient who completed treatment with nivolumab for anal squamous cell carcinoma. Patients IgG4 levels was normal on presentation. She responded to steroids but due to concerns for malignant biliary stricture, she opted for surgery, the pathology of which suggested IgG4 related disease. CONCLUSION: We hypothesize this case of IgG4 related cholangitis and pancreatitis was likely triggered by nivolumab.

The hexokinase "HKDC1" interaction with the mitochondria is essential for liver cancer progression.

Liver cancer (LC) is the fourth leading cause of death from cancer malignancies. Recently, a putative fifth hexokinase, hexokinase domain containing 1 (HKDC1), was shown to have significant overexpression in LC compared to healthy liver tissue. Using a combination of in vitro and in vivo tools, we examined the role of HKDC1 in LC development and progression. Importantly, HKDC1 ablation stops LC development and progression via its action at the mitochondria by promoting metabolic reprogramming and a shift of glucose flux away from the TCA cycle. HKDC1 ablation leads to mitochondrial dysfunction resulting in less cellular energy, which cannot be compensated by enhanced glucose uptake. Moreover, we show that the interaction of HKDC1 with the mitochondria is essential for its role in LC progression, and without this interaction, mitochondrial dysfunction occurs. As HKDC1 is highly expressed in LC cells, but only to a minimal degree in hepatocytes under normal conditions, targeting HKDC1, specifically its interaction with the mitochondria, may represent a highly selective approach to target cancer cells in LC.

Intestinal Osteopontin Protects From Alcohol-induced Liver Injury by Preserving the Gut Microbiome and the Intestinal Barrier Function.

BACKGROUND & AIMS: The gut-liver axis plays a key role in the pathogenesis of alcohol-associated liver disease (ALD). We demonstrated that Opn-/- develop worse ALD than wild-type (WT) mice; however, the role of intestinal osteopontin (OPN) in ALD remains unknown. We hypothesized that overexpression of OPN in intestinal epithelial cells (IECs) could ameliorate ALD by preserving the gut microbiome and the intestinal barrier function. METHODS: OpnKI IEC, OpnΔIEC, and WT mice were fed control or ethanol Lieber-DeCarli diet for 6 weeks. RESULTS: OpnKI IEC but not OpnΔIEC mice showed improved intestinal barrier function and protection from ALD. There were less pathogenic and more beneficial bacteria in ethanol-fed OpnKI IEC than in WT mice. Fecal microbiome transplant (FMT) from OpnKI IEC to WT mice protected from ALD. FMT from ethanol-fed WT to OpnKI IEC mice failed to induce ALD. Antimicrobial peptides, Il33, pSTAT3, aryl hydrocarbon receptor (Ahr), and tight-junction protein expression were higher in IECs from jejunum of ethanol-fed OpnKI IEC than of WT mice. Ethanol-fed OpnKI IEC showed more tryptophan metabolites and short-chain fatty acids in portal serum than WT mice. FMT from OpnKI IEC to WT mice enhanced IECs Ahr and tight-junction protein expression. Oral administration of milk OPN replicated the protective effect of OpnKI IEC mice in ALD. CONCLUSION: Overexpression of OPN in IECs or administration of milk OPN maintain the intestinal microbiome by intestinal antimicrobial peptides. The increase in tryptophan metabolites and short-chain fatty acids signaling through the Ahr in IECs, preserve the intestinal barrier function and protect from ALD.

Effect of CRISPR Knockout of AXIN1 or ARID1A on Proliferation and Migration of Porcine Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is an aggressive disease lacking effective treatment. Animal models of HCC are necessary for preclinical evaluation of the safety and efficacy of novel therapeutics. Large animal models of HCC allow testing image-guided locoregional therapies, which are widely used in the management of HCC. Models with precise tumor mutations mimicking human HCC provide valuable tools for testing precision medicine. AXIN1 and ARID1A are two of the most frequently mutated genes in human HCC. Here, we investigated the effects of knockout of AXIN1 and/or ARID1A on proliferation, migration, and chemotherapeutic susceptibility of porcine HCC cells and we developed subcutaneous tumors harboring these mutations in pigs. Gene knockout was achieved by CRISPR/Cas9 and was validated by Next Generation Sequencing. AXIN1 knockout increased the migration of porcine HCC cells but did not alter the cell proliferation. Knockout of ARID1A increased both the proliferation and migration of porcine HCC cells. Simultaneous knockout of AXIN1 and ARID1A increased the migration, but did not alter the proliferation of porcine HCC cells. The effect of gene knockout on the response of porcine HCC cells to two of the most commonly used systemic and locoregional HCC treatments was investigated; sorafenib and doxorubicin, respectively. Knockout of AXIN1 and/or ARID1A did not alter the susceptibility of porcine HCC cells to sorafenib or doxorubicin. Autologous injection of CRISPR edited HCC cells resulted in development of subcutaneous tumors in pigs, which harbored the anticipated edits in AXIN1 and/or ARID1A. This study elucidates the effects of CRISPR-mediated knockout of HCC-associated genes in porcine HCC cells, and lays the foundation for development and utilization of genetically-tailored porcine HCC models for in vivo testing of novel therapeutic approaches in a clinically-relevant large animal model.

Hepatocellular carcinoma evades RB1-induced senescence by activating the FOXM1-FOXO1 axis.

Hepatocellular carcinoma (HCC) is one of the deadliest cancers. The retinoblastoma protein (RB1), a regulator of cell proliferation, is functionally inactivated in HCC by CYCLIN D/E-mediated phosphorylation. However, the mechanism of RB1-inactivation is unclear because only small percentages of HCCs exhibit amplification of CYCLIN D/E or mutations in the CDK-inhibitory genes. We show that FOXM1, which is overexpressed and critical for HCC, plays essential roles in inactivating RB1 and suppressing RB1-induced senescence of the HCC cells. Mechanistically, FOXM1 binds RB1 and DNMT3B to repress the expression of FOXO1, leading to a decrease in the levels of the CDK-inhibitors, creating an environment for phosphorylation and inactivation of RB1. Consistent with that, inhibition of FOXM1 causes increased expression of FOXO1 with consequent activation of RB1, leading to senescence of the HCC cells, in vitro and in vivo. Also, repression-deficient mutants of FOXM1 induce senescence that is blocked by depletion of RB1 or FOXO1. We provide evidence that human HCCs rely upon this FOXM1-FOXO1 axis for phosphorylation and inactivation of RB1. The observations demonstrate the existence of a new autoregulatory loop of RB1-inactivation in HCC involving a FOXM1-FOXO1 axis that is required for phosphorylation of RB1 and for aggressive progression of HCC.