TP53 R249S mutation in hepatic organoids captures the predisposing cancer risk.

BACKGROUND AND AIMS: Major genomic drivers of hepatocellular carcinoma (HCC) are nowadays well recognized, although models to establish their roles in human HCC initiation remain scarce. Here, we used human liver organoids in experimental systems to mimic the early stages of human liver carcinogenesis from the genetic lesions of TP53 loss and L3 loop R249S mutation. In addition, chromatin immunoprecipitation sequencing (ChIP-seq) of HCC cell lines shed important functional insights into the initiation of HCC consequential to the loss of tumor-suppressive function from TP53 deficiency and gain-of-function activities from mutant p53. APPROACH AND RESULTS: Human liver organoids were generated from surgical nontumor liver tissues. CRISPR knockout of TP53 in liver organoids consistently demonstrated tumor-like morphological changes, increased in stemness and unrestricted in vitro propagation. To recapitulate TP53 status in human HCC, we overexpressed mutant R249S in TP53 knockout organoids. A spontaneous increase in tumorigenic potentials and bona fide HCC histology in xenotransplantations were observed. ChIP-seq analysis of HCC cell lines underscored gain-of-function properties from L3 loop p53 mutants in chromatin remodeling and overcoming extrinsic stress. More importantly, direct transcriptional activation of PSMF1 by mutant R249S could increase organoid resistance to endoplasmic reticulum stress, which was readily abrogated by PSMF1 knockdown in rescue experiments. In a patient cohort of primary HCC tumors and genome-edited liver organoids, quantitative polymerase chain reaction corroborated ChIP-seq findings and verified preferential genes modulated by L3 mutants, especially those enriched by R249S. CONCLUSIONS: We showed differential tumorigenic effects from TP53 loss and L3 mutations, which together confer normal hepatocytes with early clonal advantages and prosurvival functions.

Overexpression of nucleotide metabolic enzyme DUT in hepatocellular carcinoma potentiates a therapeutic opportunity through targeting its dUTPase activity.

Uracil misincorporation during DNA replication is a major cell toxic event, of which cancer cells overcome by activating the dUTPase enzyme. The DUT gene is the only known dUTPase in human. Despite reports on common upregulations in cancers, the role of DUT in human hepatocellular carcinoma (HCC) remains largely undetermined. In this study, we investigated the mechanism underlying DUT biology in HCC and tumor susceptibility to drug targeting dUTPase. Overexpression of DUT was found in 42% of HCC tumors and correlated with advanced stage HCC. Knockout of DUT in HCC cell lines showed suppressed proliferation through cell cycle arrest and a spontaneous induction of DNA damage. A protective effect from oxidative stress was also demonstrated in both knockout and overexpression DUT assays. Transcriptome analysis highlighted the NF-κB survival signaling as the downstream effector pathway of DUT in overriding oxidative stress-induced cell death. Interestingly, stably expressed DUT in liver progenitor organoids conferred drug resistance to TKI Sorafenib. Targeting dUTPase activity by TAS-114, could potentiate suppression of HCC growth that synergized with Sorafenib for better treatment sensitivity. In conclusion, upregulated DUT represents a nucleotide metabolic weakness and therapeutic opportunity in HCC.

Patient-derived tumor organoid predicts drugs response in glioblastoma: A step forward in personalized cancer therapy?

Despite significant medical advances, glioblastoma multiforme (GBM) remains a formidable therapeutic challenge. Advent of targeted capture sequencing and patients-derived organoid cultures may hold the key to scientifically sound individualized treatment approaches. We report on our initial experience of using the combination of these two technologies to create a tailored approach of systemic therapies for a patient with GBM, which challenges the conventional treatment paradigm, as well as specifically highlighting the complexities of such an approach and the potential for a more favorable treatment outcome.

Personalized therapy for hepatocellular carcinoma: Where are we now?

Following the approval of sorafenib, a large number of molecular targeted agents have been tested clinically for advanced hepatocellular carcinoma (HCC), but all have failed to demonstrate significant efficacy in clinical trials. Multiple reasons for this phenomenon have been discussed in the literature, with one reason being the lack of patient selection on the basis of molecular profile in clinical trials. The concept of drug testing in selected populations has been recently suggested by retrospective analyses of HCC clinical trials in which a particular subgroup of patients, either enriched by clinical factors or by tissue biomarkers, derived more benefits from the novel drug. In addition, recent advances in genomic medicine have enhanced the understanding of genetic and epigenetic events occurring in HCC, raising the possibility of personalizing targeted agents in accordance with the genetic make-up of the tumors. The development of 'personalized' treatment for HCC is, however, hindered by the lack of fresh biopsy of advanced HCC, the low incidence of genetic driver mutations in HCC and the tumor heterogeneity. These limitations may be overcome by sequencing cell-free DNA in plasma, frequently known as liquid biopsy, and revolution in the concept of the design of clinical trials. In this review article, we aim to: (1) give a summary of the recent sequencing results of HCC and the related implications for drug development; (2) highlight potential individual targeted agents and existing research on biomarker selection in clinical trials; and (3) discuss future directions, including the potential of liquid biopsy and umbrella clinical trials, to enhance personalized drug testing for HCC.

Viral-human chimeric transcript predisposes risk to liver cancer development and progression.

The mutagenic effect of hepatitis B (HBV) integration in predisposing risk to hepatocellular carcinoma (HCC) remains elusive. In this study, we performed transcriptome sequencing of HBV-positive HCC cell lines and showed transcription of viral-human gene fusions from the site of genome integrations. We discovered tumor-promoting properties of a chimeric HBx-LINE1 that, intriguingly, functions as a hybrid RNA. HBx-LINE1 can be detected in 23.3% of HBV-associated HCC tumors and correlates with poorer patient survival. HBx-LINE1 transgenic mice showed heightened susceptibility to diethylnitrosamine-induced tumor formation. We further show that HBx-LINE1 expression affects ß-catenin transactivity, which underlines a role in activating Wnt signaling. Thus, this study identifies a viral-human chimeric fusion transcript that functions like a long noncoding RNA to promote HCC.