Hepatic Nuclear Receptors in Cholestasis-to-Cholangiocarcinoma Pathology.

Cholestasis, characterized by impaired bile flow, is associated with an increased risk of cholangiocarcinoma (CCA), a malignancy originating from the biliary epithelium and hepatocytes. Hepatic nuclear receptors (NRs) are pivotal in regulating bile acid and metabolic homeostasis, and their dysregulation is implicated in cholestatic liver diseases and the progression of liver cancer. This review elucidates the role of various hepatic NRs in the pathogenesis of cholestasis-to-CCA progression. We explore their impact on bile acid metabolism as well as their interactions with other signaling pathways implicated in CCA development. Additionally, we introduce available murine models of cholestasis/primary sclerosing cholangitis leading to CCA and discuss the clinical potential of targeting hepatic NRs as a promising approach for the prevention and treatment of cholestatic liver diseases and CCA. Understanding the complex interplay between hepatic NRs and cholestasis-to-CCA pathology holds promise for the development of novel preventive and therapeutic strategies for this devastating disease.

Developmental ROS individualizes organismal stress resistance and lifespan.

A central aspect of aging research concerns the question of when individuality in lifespan arises1. Here we show that a transient increase in reactive oxygen species (ROS), which occurs naturally during early development in a subpopulation of synchronized Caenorhabditis elegans, sets processes in motion that increase stress resistance, improve redox homeostasis and ultimately prolong lifespan in those animals. We find that these effects are linked to the global ROS-mediated decrease in developmental histone H3K4me3 levels. Studies in HeLa cells confirmed that global H3K4me3 levels are ROS-sensitive and that depletion of H3K4me3 levels increases stress resistance in mammalian cell cultures. In vitro studies identified SET1/MLL histone methyltransferases as redox sensitive units of the H3K4-trimethylating complex of proteins (COMPASS). Our findings implicate a link between early-life events, ROS-sensitive epigenetic marks, stress resistance and lifespan.

Update on Hepatobiliary Plasticity.

The liver field has been debating for decades the contribution of the plasticity of the two epithelial compartments in the liver, hepatocytes and biliary epithelial cells (BECs), to derive each other as a repair mechanism. The hepatobiliary plasticity has been first observed in diseased human livers by the presence of biphenotypic cells expressing hepatocyte and BEC markers within bile ducts and regenerative nodules or budding from strings of proliferative BECs in septa. These observations are not surprising as hepatocytes and BECs derive from a common fetal progenitor, the hepatoblast, and, as such, they are expected to compensate for each other's loss in adults. To investigate the cell origin of regenerated cell compartments and associated molecular mechanisms, numerous murine and zebrafish models with ability to trace cell fates have been extensively developed. This short review summarizes the clinical and preclinical studies illustrating the hepatobiliary plasticity and its potential therapeutic application.

Farnesoid X Receptor Activation Impairs Liver Progenitor Cell-Mediated Liver Regeneration via the PTEN-PI3K-AKT-mTOR Axis in Zebrafish.

BACKGROUND AND AIMS: Following mild liver injury, pre-existing hepatocytes replicate. However, if hepatocyte proliferation is compromised, such as in chronic liver diseases, biliary epithelial cells (BECs) contribute to hepatocytes through liver progenitor cells (LPCs), thereby restoring hepatic mass and function. Recently, augmenting innate BEC-driven liver regeneration has garnered attention as an alternative to liver transplantation, the only reliable treatment for patients with end-stage liver diseases. Despite this attention, the molecular basis of BEC-driven liver regeneration remains poorly understood. APPROACH AND RESULTS: By performing a chemical screen with the zebrafish hepatocyte ablation model, in which BECs robustly contribute to hepatocytes, we identified farnesoid X receptor (FXR) agonists as inhibitors of BEC-driven liver regeneration. Here we show that FXR activation blocks the process through the FXR-PTEN (phosphatase and tensin homolog)-PI3K (phosphoinositide 3-kinase)-AKT-mTOR (mammalian target of rapamycin) axis. We found that FXR activation blocked LPC-to-hepatocyte differentiation, but not BEC-to-LPC dedifferentiation. FXR activation also suppressed LPC proliferation and increased its death. These defects were rescued by suppressing PTEN activity with its chemical inhibitor and ptena/b mutants, indicating PTEN as a critical downstream mediator of FXR signaling in BEC-driven liver regeneration. Consistent with the role of PTEN in inhibiting the PI3K-AKT-mTOR pathway, FXR activation reduced the expression of pS6, a marker of mTORC1 activation, in LPCs of regenerating livers. Importantly, suppressing PI3K and mTORC1 activities with their chemical inhibitors blocked BEC-driven liver regeneration, as did FXR activation. CONCLUSIONS: FXR activation impairs BEC-driven liver regeneration by enhancing PTEN activity; the PI3K-AKT-mTOR pathway controls the regeneration process. Given the clinical trials and use of FXR agonists for multiple liver diseases due to their beneficial effects on steatosis and fibrosis, the detrimental effects of FXR activation on LPCs suggest a rather personalized use of the agonists in the clinic.

Attenuating the Epidermal Growth Factor Receptor-Extracellular Signal-Regulated Kinase-Sex-Determining Region Y-Box 9 Axis Promotes Liver Progenitor Cell-Mediated Liver Regeneration in Zebrafish.

BACKGROUND AND AIMS: The liver is a highly regenerative organ, but its regenerative capacity is compromised in severe liver injury settings. In chronic liver diseases, the number of liver progenitor cells (LPCs) correlates proportionally to disease severity, implying that their inefficient differentiation into hepatocytes exacerbates the disease. Moreover, LPCs secrete proinflammatory cytokines; thus, their prolonged presence worsens inflammation and induces fibrosis. Promoting LPC-to-hepatocyte differentiation in patients with advanced liver disease, for whom liver transplantation is currently the only therapeutic option, may be a feasible clinical approach because such promotion generates more functional hepatocytes and concomitantly reduces inflammation and fibrosis. APPROACH AND RESULTS: Here, using zebrafish models of LPC-mediated liver regeneration, we present a proof of principle of such therapeutics by demonstrating a role for the epidermal growth factor receptor (EGFR) signaling pathway in differentiation of LPCs into hepatocytes. We found that suppression of EGFR signaling promoted LPC-to-hepatocyte differentiation through the mitogen-activated ERK kinase (MEK)-extracellular signal-regulated kinase (ERK)-sex-determining region Y-box 9 (SOX9) cascade. Pharmacological inhibition of EGFR or MEK/ERK promoted LPC-to-hepatocyte differentiation as well as genetic suppression of the EGFR-ERK-SOX9 axis. Moreover, Sox9b overexpression in LPCs blocked their differentiation into hepatocytes. In the zebrafish liver injury model, both hepatocytes and biliary epithelial cells contributed to LPCs. EGFR inhibition promoted the differentiation of LPCs regardless of their origin. Notably, short-term treatment with EGFR inhibitors resulted in better liver recovery over the long term. CONCLUSIONS: The EGFR-ERK-SOX9 axis suppresses LPC-to-hepatocyte differentiation during LPC-mediated liver regeneration. We suggest EGFR inhibitors as a proregenerative therapeutic drug for patients with advanced liver disease.

Extracellular vesicles mediate improved functional outcomes in engineered cartilage produced from MSC/chondrocyte cocultures.

Several recent studies have demonstrated that coculture of chondrocytes (CHs) with bone marrow-derived mesenchymal stem cells (MSCs) improves their chondrogenesis. This implies that intercellular communication dictates fate decisions in recipient cells and/or reprograms their metabolic state to support a differentiated function. While this coculture phenomenon is compelling, the differential chondroinductivity of zonal CHs on MSC cocultures, the nature of the molecular cargo, and their transport mechanisms remains undetermined. Here, we demonstrate that juvenile CHs in coculture with adult MSCs promote functional differentiation and improved matrix production. We further demonstrate that close proximity between the two cell types is a prerequisite for this response and that the outcome of this interaction improves viability, chondrogenesis, matrix formation, and homeostasis in the recipient MSCs. Furthermore, we visualized the transfer of intracellular contents from CHs to nearby MSCs and showed that inhibition of extracellular vesicle (EV) transfer blocks the synergistic effect of coculture, identifying EVs as the primary mode of communication in these cocultures. These findings will forward the development of therapeutic agents and more effective delivery systems to promote cartilage repair.

Volar locking plate removal after distal radius fracture: a 10-year retrospective study.

INTRODUCTION: Distal radius fracture (DRF) is the most common upper extremity fracture. After the introduction of volar locking plate (VLP) fixation, treatment has shifted from conservative management to more operative management. The implant removal rate after VLP fixation in patients with DRF varies and the reasons for removal and associated patient characteristics have not been clearly defined. This study aimed to compare the characteristics of patients who underwent VLP with and without subsequent implant removal. Second, the rate of implant removal according to the implant position and type was investigated. Finally, we summarized clinical outcome with implant removal, the reasons for, and complications associated with implant removal. METHODS: In this retrospective study, patient data were collected between January 1, 2008, and December 31, 2017. The study population was divided into two groups based on subsequent implant removal. Data on patient characteristics, such as age, sex, comorbidities, side of the fractured arm, the AO Foundation and Orthopaedic Trauma Association classification of the DRF, plate position grade based on the Soong classification type, type of inserted plate, insurance coverage, and treatment costs were collected. Furthermore, we investigated the reason for implant removal, clinical outcomes, and post-removal complications. RESULTS: After applying the exclusion criteria, 806 patients with a total of 814 DRFs were included in the study. Among the 806 patients who underwent VLP fixation for DRF, 252 (31.3%) patients underwent implant removal. Among the patients undergoing implant removal, the mean age was 50.8 ± 14.0 years, 94 (37.3%) were male. The average time to implant removal from the fracture fixation was 12.1 ± 9.2 months (range 1-170 months). When comparing groups, patients who underwent implant removal were significantly younger and had fewer cases of diabetes, hypertension, and cancer history. According to the Soong plate position grade, the most common position was G1 in both groups. Although there was no significant difference (p = 0.075), more G2 cases were found in the removal group (15.0%) than in the retention group (10.2%). About 66.5% of the patients with implant removal had other health insurance as well as the national service, compared with 47% of the patients with implant retention. In total, 186 patients (73.8%) underwent implant removal despite being asymptomatic after the bony union. The patient satisfaction scores improved from 4.1 to 4.4 after implant removal, and 93% of the patients answered that they would choose implant removal again. Only 10% of the patients who underwent removal reported minor complications. No major complications were reported. CONCLUSION: Although the implant removal was conducted without clinical symptoms in the majority of patients, overall patients presented improved functional outcomes with implant removal. The evidence is inconclusive regarding its necessity, however, implant removal after VLP fixation for DRF is not a challenging procedure and is not associated with major complications. LEVEL OF EVIDENCE: Level IV.

Visibility of hexagonal boron nitride on transparent substrates.

The high transmittance and low reflectance of monolayer hexagonal boron nitride (hBN) lead to its invisibility under white-light, causing serious troubles in the search, transfer, and fabrication of 2D material devices. In this work, we demonstrate enhancing the contrast of hBN on a transparent substrate by simulation and experimental observation, where the highest contrast is obtained by using a polymer-based interfacial layer on a polydimethylsiloxane (PDMS) substrate. The simulation result reveals that the contrast under short wavelength light is higher than that under long wavelength. To confirm this, the red-green-blue components are extracted from the optical color image. The blue component image shows an hBN flake clearly on the substrate, while the hBN flake fades on the green and red components. Moreover, the contrast on transparent substrates have only positive value, while opaque substrates cause both negative and positive contrast depending on the thickness of the interfacial layer. Thus, the high contrast (∼4.5%) of hBN on the PDMS substrate enables us to observe mono- and few-layer hBN flakes under white-light illumination by an optical microscope.

Redox potential change by the cystine importer affected on enzymatic antioxidant protection in Deinococcus geothermalis.

Radiation resistant bacteria genus Deinococcus species were well studied on DNA repair and anti-oxidative stress response mechanisms. There are many protection factors as enzymatic and nonenzymatic involved. One of them is intracellular redox potential as like thiol compounds including cysteine acts as primary protectant against oxidation stress. A gene cluster consisting of the genes Dgeo_1986 and Dgeo_1987 of Deinococcus geothermalis was identified as a cystine importer. The expression levels of dgeo_1986 and dgeo_1987 were up-regulated by over 60-fold and 4-fold during the late exponential (L) growth phase, respectively. The double-knockout mutant of dgeo_1986 and dgeo_1987 was reduced in cystine and thiol concentrations and leading to enhanced sensitivity against H2O2 stress. The expression of catalase (Dgeo_2728) as an enzymatic anti-oxidant is more induced in the wild-type strain than the Δdgeo_1986-87 strain at the late growth phase. The expression level of the oxidative stress response regulator OxyR (Dgeo_1888) is dependent on the intracellular redox balance. That is, when the intracellular thiol content was reduced in the wild-type strain during the L phase, OxyR was clearly induced. Interestingly, the expression level of OxyR was higher in the Δdgeo_1986-87 strain than in the wild-type strain upon H2O2 treatment. Although OxyR was induced by H2O2 treatment in Δdgeo_1986-87 strain, where intracellular redox potential of cystine was reduced as a thiol compound due to reduced cystine import, the relative level of expression of catalase was unexpectedly down-regulated. Therefore, the catalase induction system as an enzymatic antioxidant protection should be affected via the cystine importer but not rely on the OxyR controlled manner.

Characterization of the copper-sensing transcriptional regulator CopR from the hyperthermophilic archeaon Thermococcus onnurineus NA1.

A putative copper ion-sensing transcriptional regulator CopR (TON_0836) from Thermococcus onnurineus NA1 was characterized. The CopR protein consists of a winged helix-turn-helix DNA-binding domain in the amino-terminal region and a TRASH domain that is assumed to be involved in metal ion-sensing in the carboxyl-terminal region. The CopR protein was most strongly bound to a region between its own gene promoter and a counter directional promoter region for copper efflux system CopA. When the divalent metals such as nickel, cobalt, copper, and iron were present, the CopR protein was dissociated from the target promoters on electrophoretic mobility shift assay (EMSA). The highest sensible ion is copper which affected protein releasing under 10 µM concentrations. CopR recognizes a significant upstream region of TATA box on CopR own promoter and acts as a transcriptional repressor in an in vitro transcription assay. Through site-directed mutagenesis of the DNA-binding domain, R34M mutant protein completely lost the DNA-binding activity on target promoter. When the conserved cysteine residues in C144XXC147 motif 1 of the TRASH domain were mutated into glycine, the double cysteine residue mutant protein alone lost the copper-binding activity. Therefore, CopR is a copper-sensing transcriptional regulator and acts as a repressor for autoregulation and for a putative copper efflux system CopA of T. onnurineus NA1.

Maribacter pelagius sp. nov., isolated from seawater.

A Gram-stain-negative, gliding, non-endospore-forming and slightly halophilic bacterial strain, CBA3204T, was isolated from seawater and characterized by polyphasic taxonomic analysis. Phylogenetic analysis based on 16S rRNA sequences revealed that strain CBA3204T formed a distinct lineage within the family Flavobacteriaceae. The 16S rRNA sequences of strain CBA3204T had a sequence similarity level of 96.96 % to Maribacter arcticus KOPRI 20941T as the nearest phylogenetic neighbour. The strain grew optimally at 25-30 °C and in the presence of 2-4 % (w/v) NaCl. The dominant menaquinone was MK-6 and the major fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH and iso-C15 : 1 G. The DNA G+C content was 35.1 mol%. There were some differences in phenotypic properties among strain CBA3204T and other Maribacter species. On the basis of polyphasic analysis containing phenotypic, phylogenetic and chemotaxonomic data, strain CBA3204T (=KACC 17671T=JCM 19533T) is proposed as a novel species Maribacter pelagius sp. nov.

Aquimarina versatilis sp. nov., isolated from seashore sand, and emended description of the genus Aquimarina.

Strain CBA3207T, a novel Gram-stain-negative, aerobic and rod-shaped bacterium, was isolated from the seashore sand of Jeju island in South Korea. Strain CBA3207T grew optimally at 25-30 °C and pH 7.0-7.5 with 3.0-4.0 % (w/v) NaCl. It was catalase-positive, oxidase-negative, and hydrolysed starch, gelatin, and Tweens 20, 40 and 80. The 16S rRNA gene sequence of strain CBA3207T showed 96.0, 95.6, 95.6, 95.5 and 95.5 % similarity to that of Aquimarinamytili PSC33T, Aquimarinaagarivorans HQM9T, Aquimarinalatercula DSM 2041T, Aquimarinaintermedia KMM 6258T and Aquimarinaamphilecti 92VT, respectively. The major fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH, iso-C15 : 1 G and summed feature 9 (10-methyl C16 : 0 and/or iso-C17 : 1ω9c). The major respiratory quinone was menaquinone-6, and the major polar lipids were phosphatidylethanolamine, an unidentified aminolipid and six unidentified lipids. The G+C content of the genomic DNA was 38.8 mol%. Based on phenotypic, genotypic and phylogenetic analyses, strain CBA3207T represents a novel species in the genus Aquimarina, for which the name Aquimarinaversatilissp. nov. is proposed. The type strain is CBA3207T (=KACC 17666T=JCM 19528T).

Safety and efficacy of letibotulinumtoxinA(BOTULAX®) in treatment of post stroke upper limb spasticity: a randomized, double blind, multi-center, phase III clinical trial.

OBJECTIVE: To investigate a new botulinum neurotoxin type A, termed letibotulinumtoxinA(Botulax®) and compare its efficacy and safety for post-stroke upper limb spasticity with that of onabotulinumtoxinA(Botox®). DESIGN: A prospective, double-blinded, multicenter, randomized controlled clinical study. SETTING: Six university hospitals in Korea. SUBJECTS: A total of 187 stroke participants with upper limb spasticity. INTERVENTIONS: Two kinds of botulinum neurotoxin type A were used. One set of injection was performed and total injected doses were 309.21±62.48U(Botulax) and 312.64±49.99U(Botox)( P>0.05). MAIN MEASURES: Primary outcome was measured using the modified Ashworth scale for wrist flexors at week 4 and secondary outcome was measured using modified Ashworth scale for wrist flexors, elbow flexors, finger flexors, and thumb flexors as well as Global Assessment in spasticity, Disability Assessment Scale, and Caregiver Burden Scale. Safety measures including adverse events, vital signs and physical examination, and laboratory tests were also monitored. RESULTS: The mean ages for the Botulax group were 56.81±9.49 and which for the Botox group were 56.93±11.93( P>0.05). In primary outcome, the change in modified Ashworth scale for wrist flexors was -1.45±0.61 in the Botulax group and -1.40±0.57 in the Botox group, and the difference between the two groups was -0.06(95% CI:-0.23-0.12, P>0.05). In secondary outcome, both groups demonstrated significant improvements with respect to modified Ashworth scale, Global Assessment in spasticity, Disability Assessment Scale, and Caregiver Burden Scale ( P<0.05), and no significant difference was observed between the two groups ( P>0.05). In addition, safety measures showed no significant differences between the two groups ( P>0.05). CONCLUSIONS: The efficacy and safety of Botulax were comparable with those of Botox in treatment of post-stoke upper limb spasticity.

Croceitalea litorea sp. nov., isolated from seashore sand.

Strain CBA3205T is a Gram-stain-negative, non-motile and rod-shaped bacterium that was isolated from the seashore sand of Jeju Island in South Korea. Based on the phylogenetic analysis, the most closed related species was Croceitalea eckloniae DOKDO 025T, with 94.8 % sequence similarity for the 16S rRNA gene. Strain CBA3205T was observed to grow optimally at 25-30 °C and at pH 8.5 in the presence of 2-3 % (w/v) NaCl. The major fatty acids of strain CBA3205T were iso-C15 : 0, iso-C15 : 1 G, and iso-C17 : 0 3-OH. The major respiratory quinone was MK-6 and the major polar lipids were two unidentified amino-group-containing phospholipids and an unidentified polar lipid. The G+C content of the genomic DNA of strain CBA3205T was 62.5 mol%. Based on the phenotypic, genotypic and phylogenetic analyses, strain CBA3205T was considered to be a novel species belonging to the genus Croceitalea within the family Flavobacteriaceae, for which the name Croceitalea litorea sp. nov. is proposed. The type strain is CBA3205T ( = KACC 17669T = JCM 19531T).

Language-specific dysgraphia in Korean patients with right brain stroke: influence of unilateral spatial neglect.

The purpose of the present study was to investigate the relationship between Korean language-specific dysgraphia and unilateral spatial neglect in 31 right brain stroke patients. All patients were tested for writing errors in spontaneous writing, dictation, and copying tests. The dysgraphia was classified into visuospatial omission, visuospatial destruction, syllabic tilting, stroke omission, stroke addition, and stroke tilting. Twenty-three (77.4%) of the 31 patients made dysgraphia and 18 (58.1%) demonstrated unilateral spatial neglect. The visuospatial omission was the most common dysgraphia followed by stroke addition and omission errors. The highest number of errors was made in the copying and the least was in the spontaneous writing test. Patients with unilateral spatial neglect made a significantly higher number of dysgraphia in the copying test than those without. We identified specific dysgraphia features such as a right side space omission and a vertical stroke addition in Korean right brain stroke patients. In conclusion, unilateral spatial neglect influences copy writing system of Korean language in patients with right brain stroke.

NemR is a bleach-sensing transcription factor.

BACKGROUND: Little is known about how bacteria sense or respond to reactive chlorine species, such as bleach. RESULTS: NemR is a redox-regulated transcription factor which senses bleach. CONCLUSION: NemR controls expression of genes encoding electrophile detoxification enzymes, which increase bleach resistance. SIGNIFICANCE: We demonstrate a bleach-sensing bacterial response system and a new mechanism contributing to bacterial bleach survival. Hypochlorous acid (HOCl), the active component of household bleach, also functions as a powerful antimicrobial during the innate immune response. Despite its widespread use, surprisingly little is known about how cells sense or respond to HOCl. We now demonstrate that Escherichia coli NemR is a redox-regulated transcriptional repressor, which uses the oxidation status of HOCl-sensitive cysteine residues to respond to bleach and related reactive chlorine species. NemR controls bleach-mediated expression of two enzymes required for detoxification of reactive electrophiles: glyoxalase I and N-ethylmaleimide reductase. Both enzymes contribute to bacterial bleach survival. These results provide evidence that bleach resistance relies on the capacity of organisms to specifically sense reactive chlorine species and respond with the up-regulation of enzymes dedicated to detoxification of methylglyoxal and other reactive electrophiles.

Nuclear localization of huntingtin during spermatogenesis.

Huntingtin is a ubiquitous cytoplasmic protein. Mutant huntingtin causes Huntington's disease and its intranuclear inclusion is associated with cytotoxicity. Nuclear localization of normal huntingtin is detected in the oocyte up to 2.5 days post coitum. Therefore, huntingtin is expected to reside in the nucleus even before fertilization. The present study determined normal huntingtin distribution during spermatogenesis. Testicles from an adult male Sprague-Dawley rat were stained with anti-huntingtin antibody and nuclear counterstaining was performed with 4',6-diamidino-2-phenylindole. Concerning nuclear localization, huntingtin was detected in the spermatids, whereas predominant cytoplasmic localization of it was evident in the spermatogonia. Between the primary and secondary spermatocytes, huntingtin appeared to be delocalized in the nuclei when meiosis occurred. The findings provide evidence that normal huntingtin is transported to the nuclear compartment during the meiotic stage of spermatogenesis.

Cellular Plasticity in Gut and Liver Regeneration.

The intestine and liver share a unique regenerative property that sets them apart from other mammalian visceral organs. The intestinal epithelium exhibits rapid renewal, making it one of the fastest renewing tissues in humans. Under physiological conditions, intestinal stem cells within each intestinal crypt continuously differentiate into the different types of intestinal epithelial cells to maintain intestinal homeostasis. However, when exposed to tissue damage or stressful conditions such as inflammation, intestinal epithelial cells in the gastrointestinal tract exhibit plasticity, allowing fully differentiated cells to regain their stem cell properties. Likewise, hepatic epithelial cells possess a remarkable regenerative capacity to restore lost liver mass through proliferation-mediated liver regeneration. When the proliferation-mediated regenerative capacity is impaired, hepatocytes and biliary epithelial cells (BECs) can undergo plasticity-mediated regeneration and replenish each other. The transition of mammalian liver progenitor cells to hepatocytes/BECs can be observed under tightly controlled experimental conditions such as severe hepatocyte injury accompanied by the loss of regenerative capacity. In this review, we will discuss the mechanism by which cellular plasticity contributes to the regeneration process and the potential therapeutic implications of understanding and harnessing cellular plasticity in the gut and liver.

Therapeutic potential of SOX9 dysruption in Combined Hepatocellular Carcinoma-Cholangiocarcinoma.

Combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CCA) represents a challenging subtype of primary liver cancer with limited treatment options and a poor prognosis. Recently, we and others have highlighted the context-dependent roles of the biliary-specific transcription factor SOX9 in the pathogenesis of liver cancers using various Cre applications in Sox9 (flox/flox) strains, to achieve elimination for exon 2 and 3 of the Sox9 gene locus as a preventive manner. Here, we reveal the contrasting responses of developmental Sox9 elimination using Alb-Cre;Sox9 (flox/flox) ( Sox9 LKO) versus CRISPR/Cas9 -based tumor specific acute Sox9 CKO in SB-HDTVI-based Akt-YAP1 and Akt-NRAS cHCC-CCA formation. Sox9 LKO specifically abrogates the Akt-YAP1 CCA region while robustly stimulating the proliferation of remaining poorly differentiated HCC pertaining liver progenitor cell characteristics, whereas Sox9 CKO potently prevents Akt-YAP1 and Akt-NRAS cHCC-CCA development irrespective of fate of tumor cells compared to respective controls. Additionally, we find that Akt-NRAS , but not Akt-YAP1 , tumor formation is partially dependent on the Sox9-Dnmt1 cascade. Pathologically, SOX9 is indispensable for Akt-YAP1 -mediated HC-to-BEC/CCA reprogramming but required for the maintenance of CCA nodules. Lastly, therapeutic elimination of Sox9 using the OPN-CreERT2 strain combined with an inducible CRISPR/Cas9 -based Sox9 iKO significantly reduces Akt-YAP1 cHCC-CCA tumor burden, similar to Sox9 CKO. Thus, we contrast the outcomes of acute Sox9 deletion with developmental Sox9 knockout models, emphasizing the importance of considering adaptation mechanisms in therapeutic strategies. This necessitates the careful consideration of genetic liver cancer studies using developmental Cre and somatic mutant lines, particularly for genes involved in hepatic commitment during development. Our findings suggest that SOX9 elimination may hold promise as a therapeutic approach for cHCC-CCA and underscore the need for further investigation to translate these preclinical insights into clinical applications.

Context-Dependent Distinct Roles of SOX9 in Combined Hepatocellular Carcinoma-Cholangiocarcinoma.

Combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CCA) is a challenging primary liver cancer subtype with limited treatment options and a devastating prognosis. Recent studies have underscored the context-dependent roles of SOX9 in liver cancer formation in a preventive manner. Here, we revealed that liver-specific developmental Sox9 elimination using Alb-Cre;Sox9(flox/flox) (LKO) and CRISPR/Cas9-based tumor-specific acute Sox9 elimination (CKO) in SB-HDTVI-based Akt-YAP1 (AY) and Akt-NRAS (AN) cHCC-CCA models showed contrasting responses. LKO abrogates the AY CCA region while stimulating poorly differentiated HCC proliferation, whereas CKO prevents AY and AN cHCC-CCA development irrespective of tumor cell fate. Additionally, AN, but not AY, tumor formation partially depends on the Sox9-Dnmt1 cascade. SOX9 is dispensable for AY-mediated, HC-derived, LPC-like immature CCA formation but is required for their maintenance and transformation into mature CCA. Therapeutic Sox9 elimination using the OPN-CreERT2 strain combined with inducible Sox9 iKO specifically reduces AY but not AN cHCC-CCA tumors. This necessitates the careful consideration of genetic liver cancer studies using developmental Cre and somatic mutants, particularly for genes involved in liver development. Our findings suggest that SOX9 elimination may hold promise as a therapeutic approach for a subset of cHCC-CCA and highlight the need for further investigation to translate these preclinical insights into personalized clinical applications.