Molecular variation between geographical populations and subtypes indicate potential genomic heterogeneity and novel genomic features within CCA. Here, we analyze exome-sequencing data of 87 perihilar cholangiocarcinoma (pCCA) and 261 intrahepatic cholangiocarcinoma (iCCA) cases from 3 Asian centers (including 43 pCCAs and 24 iCCAs from our center). iCCA tumours demonstrate a higher tumor mutation burden and copy number alteration burden (CNAB) than pCCA tumours, and high CNAB indicates a poorer pCCA prognosis. We identify 12 significantly mutated genes and 5 focal CNA regions, and demonstrate common mutations in post-transcriptional modification-related potential driver genes METTL14 and RBM10 in pCCA tumours. Finally we demonstrate the tumour-suppressive role of METTL14, a major RNA N6-adenosine methyltransferase (m6A), and illustrate that its loss-of-function mutation R298H may act through m6A modification on potential driver gene MACF1. Our results may be valuable for better understanding of how post-transcriptional modification can affect CCA development, and highlight both similarities and differences between pCCA and iCCA.

Background: Cholangiocarcinoma (CCA) comprises a heterogeneous group of biliary tract cancer. Our previous CCA mutation pattern study focused on genes in the post-transcription modification process, among which the alternative splicing factor RBM10 captured our attention. However, the roles of RBM10 wild type and mutations in CCA remain unclear. Methods: RBM10 mutation spectrum in CCA was clarified using our initial data and other CCA genomic datasets from domestic and international sources. Real-time PCR and tissue microarray were used to detect RBM10 clinical association. Function assays were conducted to investigate the effects of RBM10 wild type and mutations on CCA. RNA sequencing was to investigate the changes in alternative splicing events in the mutation group compared to the wild-type group. Minigene splicing reporter and interaction assays were performed to elucidate the mechanism of mutation influence on alternative splicing events. Results: RBM10 mutations were more common in Chinese CCA populations and exhibited more protein truncation variants. RBM10 exerted a tumor suppressive effect in CCA and correlated with favorable prognosis of CCA patients. The overexpression of wild-type RBM10 enhanced the ASPM exon18 exon skipping event interacting with SRSF2. The C761Y mutation in the C₂H₂-type zinc finger domain impaired its interaction with SRSF2, resulting in a loss-of-function mutation. Elevated ASPM203 stabilized DVL2 and enhanced β-catenin signaling, which promoted CCA progression. Conclusions: Our results showed that RBM10^C761Y-modulated ASPM203 promoted CCA progression in a Wnt/β-catenin signaling-dependent manner. This study may enhance the understanding of the regulatory mechanisms that link mutation-altering splicing variants to CCA.

Objectives. Our previous study showed that aldose reductase (AR) played key roles in fatty liver ischemia-reperfusion (IR) injury by regulating inflammatory response and energy metabolism. Here, we aim to investigate the role and mechanism of AR in the regeneration of normal and fatty livers after liver surgery. Methods. The association of AR expression with liver regeneration was studied in the rat small-for-size liver transplantation model and the mice major hepatectomy and hepatic IR injury model with or without fatty change. The direct role and mechanism of AR in liver regeneration was explored in the AR knockout mouse model. Results. Delayed regeneration was detected in fatty liver after liver surgery in both rat and mouse models. Furthermore, the expression of AR was increased in liver after liver surgery, especially in fatty liver. In a functional study, the knockout of AR promoted liver regeneration at day 2 after major hepatectomy and IR injury. Compared to wild-type groups, the expressions of cyclins were increased in normal and fatty livers of AR knockout mice. AR inhibition increased the expressions of PPAR-α and PPAR-γ in both normal liver and fatty liver groups after major hepatectomy and IR injury. In addition, the knockout of AR promoted the expressions of SDHB, AMPK, SIRT1, and PGC1-α in liver, which regulated mitochondrial biogenesis and energy metabolism. Conclusions. The knockout of AR promoted the regeneration of normal and fatty livers through regulating energy metabolism. AR may be a new potential therapeutic target to accelerate liver regeneration after surgery.

Intrahepatic cholangiocarcinoma (ICC) remains one of the most lethal malignancies with an increasing incidence worldwide. Gemcitabine has been considered the standard first-line chemotherapeutic agent for ICC but the therapeutic response is unsatisfactory due to the development of chemoresistance. Caspase-3-mediated pyroptosis has been reported to play significant roles in chemotherapeutic response but the relevant therapeutic strategy remains unstated due to the unclear molecular mechanisms under pyroptosis in ICC. This study was designed to comprehensively explore the crucial role and underlying mechanisms of NRXN3 in pyroptosis and chemosensitivity of ICC. We performed genome-scale CRISPR-Cas9 screen integrated with transcriptomic analysis to identify key regulators of pyroptosis and gemcitabine sensitivity in ICC. In vitro and in vivo experiments were employed to investigate the effects of NRXN3 on gemcitabine-induced pyroptosis. RNA-seq and IP-MS were conducted to explore the mechanisms of NRXN3-regulated pyroptosis and chemosensitivity. NRXN3 was identified to be a critical contributor to pyroptosis and chemosensitivity in ICC. Low NRXN3 expression correlates with poor prognosis and worse therapeutic response. Mechanistically, NRXN3 competitively blocks caspase-3 binding to the RSK1 serine/threonine-protein kinase, thereby inhibiting RSK1-dependent phosphorylation of caspase-3 at T152. Inhibition of caspase-3 phosphorylation impairs its interaction with the ubiquitin ligase component FBXO1 and enhances its stability, thus facilitating caspase-3/GSDME-dependent pyroptotic cell death and chemosensitivity. Furthermore, administration of an RSK1 inhibitor or caspase-3 activator boosts the efficacy of gemcitabine in murine models of ICC. NRXN3 plays a crucial role in maintaining chemotherapy-induced pyroptosis in ICC. Targeting the NRXN3/RSK1/FBXO1/caspase-3 axis emerges as a promising strategy for ICC treatment, with the potential to improve chemosensitivity and survival.

Presence of inferior vena cava tumor thrombosis (IVCTT) is an unfavorable factor to prognosis for patients with hepatocellular carcinoma (HCC). Herein we report a case of HCC with IVC tumor thrombosis extending from the right hepatic vein (RHV) to the IVC, but it had not infiltrated the right atrium. Anterior approach right hepatectomy combined with IVC thrombectomy using trans-diaphragmatic IVC occlusion was performed for this patient. The patient is alive with disease-free at 32 months after treatment. A literature review was also performed. This case was demonstrated with the details and concepts of surgery. This case suggested that surgical resection of HCC involving the IVC, but still outside the right atrium (RA), could offer satisfactory surgical outcomes in selected patients.