Deep whole-genome analysis of 494 hepatocellular carcinomas.

Over half of hepatocellular carcinoma (HCC) cases diagnosed worldwide are in China1-3. However, whole-genome analysis of hepatitis B virus (HBV)-associated HCC in Chinese individuals is limited4-8, with current analyses of HCC mainly from non-HBV-enriched populations9,10. Here we initiated the Chinese Liver Cancer Atlas (CLCA) project and performed deep whole-genome sequencing (average depth, 120×) of 494 HCC tumours. We identified 6 coding and 28 non-coding previously undescribed driver candidates. Five previously undescribed mutational signatures were found, including aristolochic-acid-associated indel and doublet base signatures, and a single-base-substitution signature that we termed SBS_H8. Pentanucleotide context analysis and experimental validation confirmed that SBS_H8 was distinct to the aristolochic-acid-associated SBS22. Notably, HBV integrations could take the form of extrachromosomal circular DNA, resulting in elevated copy numbers and gene expression. Our high-depth data also enabled us to characterize subclonal clustered alterations, including chromothripsis, chromoplexy and kataegis, suggesting that these catastrophic events could also occur in late stages of hepatocarcinogenesis. Pathway analysis of all classes of alterations further linked non-coding mutations to dysregulation of liver metabolism. Finally, we performed in vitro and in vivo assays to show that fibrinogen alpha chain (FGA), determined as both a candidate coding and non-coding driver, regulates HCC progression and metastasis. Our CLCA study depicts a detailed genomic landscape and evolutionary history of HCC in Chinese individuals, providing important clinical implications.

Integrated Multi-Omics Landscape of Liver Metastases.

BACKGROUND & AIMS: Lack of thorough knowledge about the complicated immune microenvironment (IM) within a variety of liver metastases (LMs) leads to inappropriate treatment and unsatisfactory prognosis. We aimed to characterize IM subtypes and investigate potential mechanisms in LMs. METHODS: Mass cytometry was applied to characterize immune landscape of a primary liver cancers and liver metastases cohort. Transcriptomic and whole-exome sequencing were used to explore potential mechanisms across distinct IM subtypes. Single-cell transcriptomic sequencing, multiplex fluorescent immunohistochemistry, cell culture, mouse model, Western blot, quantitative polymerase chain reaction, and immunohistochemistry were used for validation. RESULTS: Five IM subtypes were revealed in 100 LMs and 50 primary liver cancers. Patients featured terminally exhausted (IM1) or rare T-cell-inflamed (IM2 and IM3) immune characteristics showed worse outcome. Increased intratumor heterogeneity, enriched somatic TP53, KRAS, APC, and PIK3CA mutations and hyperactivated hypoxia signaling accounted for the formation of vicious subtypes. SLC2A1 promoted immune suppression and desert via increasing proportion of Spp1+ macrophages and their inhibitory interactions with T cells in liver metastatic lesions. Furthermore, SLC2A1 promoted immune escape and LM through inducing regulatory T cells, including regulatory T cells and LAG3+CD4+ T cells in primary colorectal cancer. CONCLUSIONS: The study provided integrated multi-omics landscape of LM, uncovering potential mechanisms for vicious IM subtypes and confirming the roles of SLC2A1 in regulating tumor microenvironment remodeling in both primary tumor and LM lesions.

Hepatobiliary Tumor Organoids Reveal HLA Class I Neoantigen Landscape and Antitumoral Activity of Neoantigen Peptide Enhanced with Immune Checkpoint Inhibitors.

Neoantigen-directed therapy lacks preclinical models recapitulating neoantigen characteristics of original tumors. It is urgent to develop a platform to assess T cell response for neoantigen screening. Here, immunogenic potential of neoantigen-peptides of tumor tissues and matched organoids (n = 27 pairs) are analyzed by Score tools with whole genome sequencing (WGS)-based human leukocyte antigen (HLA)-class-I algorithms. The comparisons between 9203 predicted neoantigen-peptides from 2449 mutations of tumor tissues and 9991 ones from 2637 mutations of matched organoids demonstrate that organoids preserved majority of genetic features, HLA alleles, and similar neoantigen landscape of original tumors. Higher neoantigen load is observed in tumors with early stage. Multiomics analysis combining WGS, RNA-seq, single-cell RNA-seq, mass spectrometry filters out 93 candidate neoantigen-peptides with strong immunogenic potential for functional validation in five organoids. Immunogenic peptides are defined by inducing increased CD107aCD137IFN-γ expressions and IFN-γ secretion of CD8 cells in flow cytometry and enzyme-linked immunosorbent assay assays. Nine immunogenic peptides shared by at least two individuals are validated, including peptide from TP53R90S . Organoid killing assay confirms the antitumor activity of validated immunogenic peptide-reactive CD8 cells, which is further enhanced in the presence of immune checkpoint inhibitors. The study characterizes HLA-class-I neoantigen landscape in hepatobiliary tumor, providing practical strategy with tumor organoid model for neoantigen-peptide identification in personalized immunotherapy.

The effect of biliary obstruction, biliary drainage and bile reinfusion on bile acid metabolism and gut microbiota in mice.

BACKGROUND & AIMS: Preoperative obstructive jaundice is usually associated with higher post-operative mortality. Although external biliary drainage (EBD) has been widely used to relieve obstructive jaundice, the role of bile reinfusion after EBD is still controversial. The aim of our study was to study the effects of biliary obstruction, biliary drainage and bile reinfusion on bile acid metabolism and gut microbiota. METHODS: Firstly, we created a mice bile drainage collection (BDC) model to simulate the process of biliary obstruction, drainage and bile reinfusion. Then, we analysed the faecal, serum, liver and bile samples to investigate the effects of the process on bile acid profiles and gut microbiota. Finally, we evaluated the clinical effects of bile reinfusion. RESULTS: We evaluated the bile acid profiles of faeces, serum, liver and bile of normal mice. During biliary obstruction, secondary bile acids can still be produced, and increased in the liver and serum of mice. Compared with no bile reinfusion, bile reinfusion was beneficial to the recovery of T-ωMCA in the liver and bile, and can restore the colon crypt length shortened by biliary obstruction. Only Ruminococcus_1 proliferated when the biliary obstruction lasted for 12 days. In the clinic, bile reinfusion cannot accelerate the patient's perioperative recovery or prolong long-term survival. CONCLUSION: We have successfully created a mice bile drainage collection model. Short-term bile reinfusion can partially benefit the recovery of the secondary bile acids in the liver and bile, but hardly benefit the patient's perioperative recovery or long-term survival. (247 words).

Comprehensive analysis of spatial architecture in primary liver cancer.

Heterogeneity is the major challenge for cancer prevention and therapy. Here, we first constructed high-resolution spatial transcriptomes of primary liver cancers (PLCs) containing 84,823 spots within 21 tissues from seven patients. The progressive comparison of spatial tumor microenvironment (TME) characteristics from nontumor to leading-edge to tumor regions revealed that the tumor capsule potentially affects intratumor spatial cluster continuity, transcriptome diversity, and immune cell infiltration. Locally, we found that the bidirectional ligand-receptor interactions at the 100-µm-wide cluster-cluster boundary contribute to maintaining intratumor architecture and the PROM1+ and CD47+ cancer stem cell niches are related to TME remodeling and tumor metastasis. Last, we proposed a TLS-50 signature to accurately locate tertiary lymphoid structures (TLSs) spatially and unveiled that the distinct composition of TLSs is shaped by their distance to tumor cells. Our study provides previous unknown insights into the diverse tumor ecosystem of PLCs and has potential benefits for cancer intervention.

Discovery of a Carbamoyl Phosphate Synthetase 1-Deficient HCC Subtype With Therapeutic Potential Through Integrative Genomic and Experimental Analysis.

BACKGROUND AND AIMS: Metabolic reprogramming plays an important role in tumorigenesis. However, the metabolic types of different tumors are diverse and lack in-depth study. Here, through analysis of big databases and clinical samples, we identified a carbamoyl phosphate synthetase 1 (CPS1)-deficient hepatocellular carcinoma (HCC) subtype, explored tumorigenesis mechanism of this HCC subtype, and aimed to investigate metabolic reprogramming as a target for HCC prevention. APPROACH AND RESULTS: A pan-cancer study involving differentially expressed metabolic genes of 7,764 tumor samples in 16 cancer types provided by The Cancer Genome Atlas (TCGA) demonstrated that urea cycle (UC) was liver-specific and was down-regulated in HCC. A large-scale gene expression data analysis including 2,596 HCC cases in 7 HCC cohorts from Database of HCC Expression Atlas and 17,444 HCC cases from in-house hepatectomy cohort identified a specific CPS1-deficent HCC subtype with poor clinical prognosis. In vitro and in vivo validation confirmed the crucial role of CPS1 in HCC. Liquid chromatography-mass spectrometry assay and Seahorse analysis revealed that UC disorder (UCD) led to the deceleration of the tricarboxylic acid cycle, whereas excess ammonia caused by CPS1 deficiency activated fatty acid oxidation (FAO) through phosphorylated adenosine monophosphate-activated protein kinase. Mechanistically, FAO provided sufficient ATP for cell proliferation and enhanced chemoresistance of HCC cells by activating forkhead box protein M1. Subcutaneous xenograft tumor models and patient-derived organoids were employed to identify that blocking FAO by etomoxir may provide therapeutic benefit to HCC patients with CPS1 deficiency. CONCLUSIONS: In conclusion, our results prove a direct link between UCD and cancer stemness in HCC, define a CPS1-deficient HCC subtype through big-data mining, and provide insights for therapeutics for this type of HCC through targeting FAO.

Seven interferon gamma response genes serve as a prognostic risk signature that correlates with immune infiltration in lung adenocarcinoma.

Interferon-gamma (IFN-γ) plays a complex role in modulating tumor microenvironment during lung adenocarcinoma (LUAD) development. In order to define the role of IFN-γ response genes in LUAD progression, we characterized the gene expression, mutation profile, protein-protein interaction of 24 IFN-γ response genes, which exhibited significant hazard ratio in overall survival. Two subgroups of LUAD from the TCGA cohort, which showed significant difference in the survival rate, were identified based on the expression of these genes. Furthermore, LASSO penalized cox regression model was used to derive a risk signature comprising seven IFN-γ response genes, including CD74, CSF2RB, PTPN6, MT2A, NMI, LATS2, and PFKP, which can serve as an independent prognostic predictor of LUAD. The risk signature was validated in an independent LUAD cohort. The high risk group is enriched with genes regulating cell cycle and DNA replication, as well as a high level of pro-tumor immune cells. In addition, the risk score is negatively correlated with the expression of immune metagenes, but positively correlated with DNA damage repair genes. Our findings reveal that seven-gene risk signature can be a valuable prognostic predictor for LUAD, and they are crucial participants in tumor microenvironment of LUAD.

Cancer stem cell property and gene signature in bone-metastatic Breast Cancer cells.

The majority of the deaths from breast cancer is due to metastasis. Bone is the most common organ to which breast cancer cells metastasize. The mechanism regulating the bone-metastatic preference remains unclear; there is a lack of a gene signature to distinguish bone-metastatic breast cancer cells. Herein, florescence-labeled MDA-MB-231 cells were transplanted into the fat pads of of the mammary gland in nude mice to generate breast tumors. Tumor cells invaded into the circulation were tracked by in vivo flow cytometry system. Metastatic tumor cells in the bone were isolated using fluorescent-activated cell sorting technique, followed by assays of cell colony formation, migration and invasion, mammosphere formation in vitro, mammary gland tumorigenesis in vivo, and Next-Generation Sequencing analysis as well. Through tumor regeneration and cell sorting, two bone-metastatic cell sublines were derived from MDA-MB-231 cells; which showed higher abilities to proliferate, migrate, invade and epithelial-to-mesenchymal transit in vitro, and stronger ability to regenerate tumors and metastasize to the bone in vivo. Both cell sublines exhibited cancer stem cell-like characteristics including higher expression levels of stem cell markers and stronger ability for mommaspheres formation. Furthermore, a Normal Distribution-like pattern of the bone-metastatic cells invading into circulation was firstly identified. Deep-sequencing analysis indicated upregulation of multiple signaling pathways in regulating EMT, cell membrane budding and morphologic change, lipid metabolism, and protein translation, which are required to provide adequate metabolic enzymes, structural proteins, and energy for the cells undergoing metastasis. In conclusion, we established two bone-metastatic breast cancer cell sublines, carrying higher degree of stemness and malignancy. The gene signature distinguishing the bone-metastatic breast cancer cells holds therapeutic potentials in prevention of breast cancer metastasis to the bone.