SERPINE1: Role in Cholangiocarcinoma Progression and a Therapeutic Target in the Desmoplastic Microenvironment.

A heterogenous population of inflammatory elements, other immune and nonimmune cells and cancer-associated fibroblasts (CAFs) are evident in solid malignancies where they coexist with the growing tumor mass. In highly desmoplastic malignancies, CAFs are the prominent mesenchymal cell type in the tumor microenvironment (TME), where their presence and abundance signal a poor prognosis. CAFs play a major role in the progression of various cancers by remodeling the supporting stroma into a dense, fibrotic matrix while secreting factors that promote the maintenance of cancer stem-like characteristics, tumor cell survival, aggressive growth and metastasis and reduced sensitivity to chemotherapeutics. Tumors with high stromal fibrotic signatures are more likely to be associated with drug resistance and eventual relapse. Identifying the molecular underpinnings for such multidirectional crosstalk among the various normal and neoplastic cell types in the TME may provide new targets and novel opportunities for therapeutic intervention. This review highlights recent concepts regarding the complexity of CAF biology in cholangiocarcinoma, a highly desmoplastic cancer. The discussion focuses on CAF heterogeneity, functionality in drug resistance, contributions to a progressively fibrotic tumor stroma, the involved signaling pathways and the participating genes.

Cost-effectiveness of ivosidenib versus chemotherapy for previously treated IDH1-mutant advanced intrahepatic cholangiocarcinoma in Taiwan.

BACKGROUND: International guidelines recommend ivosidenib followed by modified FOLFOX (mFOLFOX) for advanced intrahepatic cholangiocarcinoma (ICC) with isocitrate dehydrogenase 1 (IDH1) mutations. Taiwan National Health Insurance covers only fluorouracil/leucovorin (5-FU/LV) chemotherapy for this ICC group, and there has been no prior economic evaluation of ivosidenib. Therefore, we aimed to assess ivosidenib's cost-effectiveness in previously treated, advanced ICC-presenting IDH1 mutations compared with mFOLFOX or 5-FU/LV. METHODS: A 3-state partitioned survival model was employed to assess ivosidenib's cost-effectiveness over a 10-year horizon with a 3% discount rate, setting the willingness-to-pay threshold at 3 times the 2022 GDP per capita. Efficacy data for Ivosidenib, mFOLFOX, and 5-FU/LV were sourced from the ClarIDHy, ABC06, and NIFTY trials, respectively. Ivosidenib's cost was assumed to be NT$10,402/500 mg. Primary outcomes included incremental cost-effectiveness ratios (ICERs) and net monetary benefit. Deterministic sensitivity analyses (DSA) and probabilistic sensitivity analyses (PSA) were employed to evaluate uncertainty and explore price reduction scenarios. RESULTS: Ivosidenib exhibited ICERs of NT$6,268,528 and NT$5,670,555 compared with mFOLFOX and 5-FU/LV, respectively, both exceeding the established threshold. PSA revealed that ivosidenib was unlikely to be cost-effective, except when it was reduced to NT$4,161 and NT$5,201/500 mg when compared with mFOLFOX and 5-FU/LV, respectively. DSA underscored the significant influence of ivosidenib's cost and utility values on estimate uncertainty. CONCLUSIONS: At NT$10,402/500 mg, ivosidenib was not cost-effective for IDH1-mutant ICC patients compared with mFOLFOX or 5-FU/LV, indicating that a 50-60% price reduction is necessary for ivosidenib to be cost-effective in this patient group.

Bortezomib in previously treated phosphatase and tension homology-deficient patients with advanced intrahepatic cholangiocarcinoma: An open-label, prospective and single-centre phase II trial.

INTRODUCTION: Intrahepatic cholangiocarcinoma (ICC) is characterized by a dismal prognosis with limited therapeutic alternatives. To explore phosphatase and tension homolog (PTEN) as a biomarker for proteasome inhibition in ICC, we conducted a phase II trial to assess the second-line efficacy of bortezomib in PTEN-deficient advanced ICC patients. METHODS: A total of 130 patients with advanced ICC in our centre were screened by PTEN immunohistochemical staining between 1 July 2017, and 31 December 2021, and 16 patients were ultimately enrolled and treated with single-agent bortezomib 1.3 mg/m2 on days 1, 4, 8 and 11 of a 21-day cycle. The primary endpoint was the objective response rate (ORR) according to Response Evaluation Criteria in Solid Tumors v1.1. RESULTS: The median follow-up was 6.55 months (95% confidence interval [CI]: 0.7-19.9 months). Among the 16 enrolled patients, the ORR was 18.75% (3/16) and the disease control rate was 43.75% (7/16). The median progress-free survival was 2.95 months (95% CI: 2.1-5.1 months) and the median overall survival (mOS) was 7.2 months (95% CI: 0.7-21.6 months) in the intent-to-treat-patients. Treatment-related adverse events of any grade were reported in 16 patients, with thrombopenia being the most common toxicity. Patients with PTEN staining scores of 0 were more likely to benefit from bortezomib than those with staining scores > 0. CONCLUSIONS: Bortezomib yielded an encouraging objective response and a favourable OS as a second-line agent in PTEN-deficient ICC patients. Our findings suggest bortezomib as a promising therapeutic option for patients with PTEN-deficient ICC. HIGHLIGHTS: There is a limited strategy for the second-line option of intrahepatic cholangiocarcinoma (ICC). This investigator-initiated phase 2 study evaluated bortezomib in ICC patients with phosphatase and tension homology deficiency. The overall response rate was 18.75% and the overall survival was 7.2 months in the intent-to-treat cohort. These results justify further developing bortezomib in ICC patients with PTEN deficiency.

SRC inhibition enables formation of a growth suppressive MAGI1-PP2A complex in isocitrate dehydrogenase-mutant cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (ICC) is an aggressive bile duct malignancy that frequently exhibits isocitrate dehydrogenase (IDH1/IDH2) mutations. Mutant IDH (IDHm) ICC is dependent on SRC kinase for growth and survival and is hypersensitive to inhibition by dasatinib, but the molecular mechanism underlying this sensitivity is unclear. We found that dasatinib reduced p70 S6 kinase (S6K) and ribosomal protein S6 (S6), leading to substantial reductions in cell size and de novo protein synthesis. Using an unbiased phosphoproteomic screen, we identified membrane-associated guanylate kinase, WW, and PDZ domain containing 1 (MAGI1) as an SRC substrate in IDHm ICC. Biochemical and functional assays further showed that SRC inhibits a latent tumor-suppressing function of the MAGI1-protein phosphatase 2A (PP2A) complex to activate S6K/S6 signaling in IDHm ICC. Inhibiting SRC led to activation and increased access of PP2A to dephosphorylate S6K, resulting in cell death. Evidence from patient tissue and cell line models revealed that both intrinsic and extrinsic resistance to dasatinib is due to increased phospho-S6 (pS6). To block pS6, we paired dasatinib with the S6K/AKT inhibitor M2698, which led to a marked reduction in pS6 in IDHm ICC cell lines and patient-derived organoids in vitro and substantial growth inhibition in ICC patient-derived xenografts in vivo. Together, these results elucidated the mechanism of action of dasatinib in IDHm ICC, revealed a signaling complex regulating S6K phosphorylation independent of mTOR, suggested markers for dasatinib sensitivity, and described a combination therapy for IDHm ICC that may be actionable in the clinic.

Integrative analyses of bulk and single-cell transcriptomics reveals the infiltration and crosstalk of cancer-associated fibroblasts as a novel predictor for prognosis and microenvironment remodeling in intrahepatic cholangiocarcinoma.

BACKGROUND: Intrahepatic cholangiocarcinoma (ICC) is a highly malignant neoplasm and characterized by desmoplastic matrix. The heterogeneity and crosstalk of tumor microenvironment remain incompletely understood. METHODS: To address this gap, we performed Weighted Gene Co-expression Network Analysis (WGCNA) to identify and construct a cancer associated fibroblasts (CAFs) infiltration biomarker. We also depicted the intercellular communication network and important receptor-ligand complexes using the single-cell transcriptomics analysis of tumor and Adjacent normal tissue. RESULTS: Through the intersection of TCGA DEGs and WGCNA module genes, 784 differential genes related to CAFs infiltration were obtained. After a series of regression analyses, the CAFs score was generated by integrating the expressions of EVA1A, APBA2, LRRTM4, GOLGA8M, BPIFB2, and their corresponding coefficients. In the TCGA-CHOL, GSE89748, and 107,943 cohorts, the high CAFs score group showed unfavorable survival prognosis (p < 0.001, p = 0.0074, p = 0.028, respectively). Additionally, a series of drugs have been predicted to be more sensitive to the high-risk group (p < 0.05). Subsequent to dimension reduction and clustering, thirteen clusters were identified to construct the single-cell atlas. Cell-cell interaction analysis unveiled significant enhancement of signal transduction in tumor tissues, particularly from fibroblasts to malignant cells via diverse pathways. Moreover, SCENIC analysis indicated that HOXA5, WT1, and LHX2 are fibroblast specific motifs. CONCLUSIONS: This study reveals the key role of fibroblasts - oncocytes interaction in the remodeling of the immunosuppressive microenvironment in intrahepatic cholangiocarcinoma. Subsequently, it may trigger cascade activation of downstream signaling pathways such as PI3K-AKT and Notch in tumor, thus initiating tumorigenesis. Targeted drugs aimed at disrupting fibroblasts-tumor cell interaction, along with associated enrichment pathways, show potential in mitigating the immunosuppressive microenvironment that facilitates tumor progression.

Practical considerations for pathological diagnosis and molecular profiling of cholangiocarcinoma: an expert review for best practices.

INTRODUCTION: Advances in precision medicine have expanded access to targeted therapies and demand for molecular profiling of cholangiocarcinoma (CCA) patients in routine clinical practice. However, pathologists face challenges in establishing a definitive intrahepatic CCA (iCCA) diagnosis while preserving sufficient tissue for molecular profiling. Additionally, they frequently face challenges in optimal tissue handling to preserve nucleic acid integrity. AREAS COVERED: This article first identifies the challenges in establishing a definitive diagnosis of iCCA in a lesional liver biopsy while preserving sufficient tissue for molecular profiling. Then, the authors explore the clinical value of molecular profiling, the basic principles of single gene and next-generation sequencing (NGS) techniques, and the challenges in tissue sampling for genomic testing. They also propose an algorithm for best practice in tissue management for molecular profiling of CCA. EXPERT OPINION: Several practical challenges face pathologists during tissue sampling and processing for molecular profiling. Optimized tissue processing, careful tissue handling, and selection of appropriate approaches to molecular testing are essential to ensure that the highest possible quality of diagnostic information is provided in the greatest proportion of cases.

Combined hepatocellular-cholangiocarcinoma: from genesis to molecular pathways and therapeutic strategies.

Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) are the most common primary liver cancers. Little is known about the combined hepatocellular-cholangiocarcinoma (cHCC-ICC) variant and the proper therapeutic strategies. Out of over 1200 available studies about cHCC-ICC, we selected the most representative ones that reflected updated information with application to individualized therapy. Based on literature data and own experience, we hypothesize that two molecular groups of cHCC-ICC can be identified. The proposed division might have a significant therapeutic role. Most cases develop, like HCC, on a background of cirrhosis and hepatitis and share characteristics with HCC; thus, they are named HCC-type cHCC-ICC and therapeutic strategies might be like those for HCC. This review also highlights a new carcinogenic perspective and identifies, based on literature data and the own experience, a second variant of cHCC-ICC called ICC-type cHCC-ICC. Contrary to HCC, these cases show a tendency for lymph node metastases and ICC components in the metastatic tissues. No guidelines have been established yet for such cases. Individualized therapy should be, however, oriented toward the immunoprofile of the primary tumor and metastatic cells, and different therapeutic strategies should be used in patients with HCC- versus ICC-type cHCC-ICC.

FGFR inhibition blocks NF-ĸB-dependent glucose metabolism and confers metabolic vulnerabilities in cholangiocarcinoma.

Genomic alterations that activate Fibroblast Growth Factor Receptor 2 (FGFR2) are common in intrahepatic cholangiocarcinoma (ICC) and confer sensitivity to FGFR inhibition. However, the depth and duration of response is often limited. Here, we conduct integrative transcriptomics, metabolomics, and phosphoproteomics analysis of patient-derived models to define pathways downstream of oncogenic FGFR2 signaling that fuel ICC growth and to uncover compensatory mechanisms associated with pathway inhibition. We find that FGFR2-mediated activation of Nuclear factor-κB (NF-κB) maintains a highly glycolytic phenotype. Conversely, FGFR inhibition blocks glucose uptake and glycolysis while inciting adaptive changes, including switching fuel source utilization favoring fatty acid oxidation and increasing mitochondrial fusion and autophagy. Accordingly, FGFR inhibitor efficacy is potentiated by combined mitochondrial targeting, an effect enhanced in xenograft models by intermittent fasting. Thus, we show that oncogenic FGFR2 signaling drives NF-κB-dependent glycolysis in ICC and that metabolic reprogramming in response to FGFR inhibition confers new targetable vulnerabilities.

The deubiquitinase USP5 promotes cholangiocarcinoma progression by stabilizing YBX1.

AIMS: Ubiquitin specific peptidase 5 (USP5), a member of deubiquitinating enzymes, has garnered significant attention for its crucial role in cancer progression. This study aims to explore the role of USP5 and its potential molecular mechanisms in cholangiocarcinoma (CCA). MAIN METHODS: To explore the effect of USP5 on CCA, gain-of-function and loss-of-function assays were conducted in human CCA cell lines RBE and HCCC9810. The CCK8, colony-forming assay, EDU, flow cytometry, transwell assay and xenografts were used to assess cell proliferation, migration and tumorigenesis. Western blot and immunohistochemistry were performed to measure the expression of related proteins. Immunoprecipitation and immunofluorescence were applied to identify the interaction between USP5 and Y box-binding protein 1 (YBX1). Ubiquitination assays and cycloheximide chase assays were carried out to confirm the effect of USP5 on YBX1. KEY FINDINGS: We found USP5 is highly expressed in CCA tissues, and upregulated USP5 is required for the cancer progression. Knockdown of USP5 inhibited cell proliferation, migration and epithelial-mesenchymal transition (EMT) in vitro, along with suppressed xenograft tumor growth and metastasis in vivo. Mechanistically, USP5 could interact with YBX1 and stabilize YBX1 by deubiquitination in CCA cells. Additionally, silencing of USP5 hindered the phosphorylation of YBX1 at serine 102 and its subsequent translocation to the nucleus. Notably, the effect induced by USP5 overexpression in CCA cells was reversed by YBX1 silencing. SIGNIFICANCE: Our findings reveal that USP5 is required for cell proliferation, migration and EMT in CCA by stabilizing YBX1, suggesting USP5-YBX1 axis as a promising therapeutic target for CCA.

Cholangiocarcinoma combined with biliary obstruction: an exosomal circRNA signature for diagnosis and early recurrence monitoring.

Cholangiocarcinoma (CCA) is a highly malignant biliary tract cancer with currently suboptimal diagnostic and prognostic approaches. We present a novel system to monitor CCA using exosomal circular RNA (circRNA) via serum and biliary liquid biopsies. A pilot cohort consisting of patients with CCA-induced biliary obstruction (CCA-BO, n = 5) and benign biliary obstruction (BBO, n = 5) was used to identify CCA-derived exosomal circRNAs through microarray analysis. This was followed by a discovery cohort (n = 20) to further reveal a CCA-specific circRNA complex (hsa-circ-0000367, hsa-circ-0021647, and hsa-circ-0000288) in both bile and serum exosomes. In vitro and in vivo studies revealed the three circRNAs as promoters of CCA invasiveness. Diagnostic and prognostic models were established and verified by two independent cohorts (training cohort, n = 184; validation cohort, n = 105). An interpreter-free diagnostic model disclosed the diagnostic power of biliary exosomal circRNA signature (Bile-DS, AUROC = 0.947, RR = 6.05) and serum exosomal circRNA signature (Serum-DS, AUROC = 0.861, RR = 4.04) compared with conventional CA19-9 (AUROC = 0.759, RR = 2.08). A prognostic model of CCA undergoing curative-intent surgery was established by calculating early recurrence score, verified with bile samples (Bile-ERS, C-index=0.783) and serum samples (Serum-ERS, C-index = 0.782). These models, combined with other prognostic factors revealed by COX-PH model, enabled the establishment of nomograms for recurrence monitoring of CCA. Our study demonstrates that the exosomal triple-circRNA panel identified in both bile and serum samples serves as a novel diagnostic and prognostic tool for the clinical management of CCA.

Bmi1 facilitates the progression of cholangiocarcinoma by inhibiting Foxn2 expression dependent on a histone H2A ubiquitination manner.

Cholangiocarcinoma (CCA), an exceptionally aggressive malignancy originating from the epithelium of the bile duct, poses a formidable challenge in cancer research and clinical management. Currently, attention is focused on exploring the oncogenic role and prognostic implications associated with Bmi1 in the context of CCA. In our study, we assessed the correlation of Bmi1 and Foxn2 expression across all types of CCA and evaluated their prognostic significance. Our results demonstrated that Bmi1 exhibits significantly upregulated expression in CCA tissues, while Foxn2 expression shows an inverse pattern. Simultaneously, the high expression of Bmi1, coupled with the low expression of Foxn2, indicates an unfavorable prognosis. Through in vitro and in vivo experiments, we confirmed the crucial role of Foxn2 in the proliferation, metastasis, and epithelial-mesenchymal transition (EMT) of CCA. Mechanistically, Bmi1 promotes the ubiquitination of histone H2A (H2AUb), leading to chromatin opening attenuation and a decrease in Foxn2 expression, ultimately driving CCA progression. Additionally, we described the potential value of Bmi1 and H2AUb inhibitors in treating CCA through in vitro experiments and orthotopic models. This study is of significant importance in deepening our understanding of the interaction between Bmi1 and Foxn2 in CCA and has the potential to advance the development of precision therapies for CCA.

The histone lysine acetyltransferase KAT2B inhibits cholangiocarcinoma growth: evidence for interaction with SP1 to regulate NF2-YAP signaling.

BACKGROUND: Cholangiocarcinoma (CCA) is a highly malignant cancer of the biliary tract with poor prognosis. Further mechanistic insights into the molecular mechanisms of CCA are needed to develop more effective target therapy. METHODS: The expression of the histone lysine acetyltransferase KAT2B in human CCA was analyzed in human CCA tissues. CCA xenograft was developed by inoculation of human CCA cells with or without KAT2B overexpression into SCID mice. Western blotting, ChIP-qPCR, qRT-PCR, protein immunoprecipitation, GST pull-down and RNA-seq were performed to delineate KAT2B mechanisms of action in CCA. RESULTS: We identified KAT2B as a frequently downregulated histone acetyltransferase in human CCA. Downregulation of KAT2B was significantly associated with CCA disease progression and poor prognosis of CCA patients. The reduction of KAT2B expression in human CCA was attributed to gene copy number loss. In experimental systems, we demonstrated that overexpression of KAT2B suppressed CCA cell proliferation and colony formation in vitro and inhibits CCA growth in mice. Mechanistically, forced overexpression of KAT2B enhanced the expression of the tumor suppressor gene NF2, which is independent of its histone acetyltransferase activity. We showed that KAT2B was recruited to the promoter region of the NF2 gene via interaction with the transcription factor SP1, which led to enhanced transcription of the NF2 gene. KAT2B-induced NF2 resulted in subsequent inhibition of YAP activity, as reflected by reduced nuclear accumulation of oncogenic YAP and inhibition of YAP downstream genes. Depletion of NF2 was able to reverse KAT2B-induced reduction of nuclear YAP and subvert KAT2B-induced inhibition of CCA cell growth. CONCLUSIONS: This study provides the first evidence for an important tumor inhibitory effect of KAT2B in CCA through regulation of NF2-YAP signaling and suggests that this signaling cascade may be therapeutically targeted for CCA treatment.

Bioinformatics and system biology approaches to determine the connection of SARS-CoV-2 infection and intrahepatic cholangiocarcinoma.

INTRODUCTION: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of coronavirus disease 2019 (COVID-19), has infected millions of individuals worldwide, which poses a severe threat to human health. COVID-19 is a systemic ailment affecting various tissues and organs, including the lungs and liver. Intrahepatic cholangiocarcinoma (ICC) is one of the most common liver cancer, and cancer patients are particularly at high risk of SARS-CoV-2 infection. Nonetheless, few studies have investigated the impact of COVID-19 on ICC patients. METHODS: With the methods of systems biology and bioinformatics, this study explored the link between COVID-19 and ICC, and searched for potential therapeutic drugs. RESULTS: This study identified a total of 70 common differentially expressed genes (DEGs) shared by both diseases, shedding light on their shared functionalities. Enrichment analysis pinpointed metabolism and immunity as the primary areas influenced by these common genes. Subsequently, through protein-protein interaction (PPI) network analysis, we identified SCD, ACSL5, ACAT2, HSD17B4, ALDOA, ACSS1, ACADSB, CYP51A1, PSAT1, and HKDC1 as hub genes. Additionally, 44 transcription factors (TFs) and 112 microRNAs (miRNAs) were forecasted to regulate the hub genes. Most importantly, several drug candidates (Periodate-oxidized adenosine, Desipramine, Quercetin, Perfluoroheptanoic acid, Tetrandrine, Pentadecafluorooctanoic acid, Benzo[a]pyrene, SARIN, Dorzolamide, 8-Bromo-cAMP) may prove effective in treating ICC and COVID-19. CONCLUSION: This study is expected to provide valuable references and potential drugs for future research and treatment of COVID-19 and ICC.

Generation of Metastatic Cholangiocarcinoma Patient-Derived Xenograft Models.

Cholangiocarcinoma (CCA) poses a substantial clinical hurdle as it is often detected at advanced metastatic stages with limited therapeutic options. To enhance our understanding of advanced CCA, it is imperative to establish preclinical models that faithfully recapitulate the disease's characteristics. Patient-derived xenograft (PDX) models have emerged as a valuable approach in cancer research, offering an avenue to reproduce and study the genomic, histologic, and molecular features of the original human tumors. By faithfully preserving the heterogeneity, microenvironmental interactions, and drug responses observed in human tumors, PDX models serve as highly relevant and predictive preclinical tools. Here, we present a comprehensive protocol that outlines the step-by-step process of generating and maintaining PDX models using biopsy samples from patients with advanced metastatic CCA. The protocol encompasses crucial aspects such as tissue processing, xenograft transplantation, and subsequent monitoring of the PDX models. By employing this protocol, we aim to establish a robust collection of PDX models that accurately reflect the genomic landscape, histologic diversity, and therapeutic responses observed in advanced CCA, thereby enabling improved translational research, drug development, and personalized treatment strategies for patients facing this challenging disease.

YBX1 promotes stemness and cisplatin insensitivity in intrahepatic cholangiocarcinoma via the AKT/ß-catenin axis.

BACKGROUND: Intrahepatic cholangiocarcinoma (ICC) is a highly aggressive malignancy characterized by a poor prognosis and closely linked to tumor stemness. However, the key molecules that regulate ICC stemness remain elusive. Although Y-box binding protein 1 (YBX1) negatively affects prognosis in various cancers by enhancing stemness and chemoresistance, its effect on stemness and cisplatin sensitivity in ICC remains unclear. METHODS: Three bulk and single-cell RNA-seq datasets were analyzed to investigate YBX1 expression in ICC and its association with stemness. Clinical samples and colony/sphere formation assays validated the role of YBX1 in stemness and sensitivity to cisplatin. AZD5363 and KYA1979K explored the interaction of YBX1 with the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/AKT) and WNT/ß-catenin pathways. RESULTS: YBX1 was significantly upregulated in ICC, correlated with worse overall survival and shorter postoperative recurrence time, and was higher in chemotherapy-non-responsive ICC tissues. The YBX1-high group exhibited significantly elevated stemness scores, and genes linked to YBX1 upregulation were enriched in multiple stemness-related pathways. Moreover, YBX1 expression is significantly correlated with several stemness-related genes (SOX9, OCT4, CD133, CD44 and EPCAM). Additionally, YBX1 overexpression significantly enhanced the colony- and spheroid-forming abilities of ICC cells, accelerated tumor growth in vivo and reduced their sensitivity to cisplatin. Conversely, the downregulation of YBX1 exerted the opposite effect. The transcriptomic analysis highlighted the link between YBX1 and the PI3K/AKT and WNT/ß-catenin pathways. Further, AZD5363 and KYA1979K were used to clarify that YBX1 promoted ICC stemness through the regulation of the AKT/ß-catenin axis. CONCLUSIONS: YBX1 is upregulated in ICC and promotes stemness and cisplatin insensitivity via the AKT/ß-catenin axis. Our study describes a novel potential therapeutic target for improving ICC prognosis.

N6-methyladenosine-modified circSLCO1B3 promotes intrahepatic cholangiocarcinoma progression via regulating HOXC8 and PD-L1.

BACKGROUND: Refractoriness to surgical resection and chemotherapy makes intrahepatic cholangiocarcinoma (ICC) a fatal cancer of the digestive system with high mortality and poor prognosis. Important function invests circRNAs with tremendous potential in biomarkers and therapeutic targets. Nevertheless, it is still unknown how circRNAs contribute to the evolution of ICC. METHODS: CircRNAs in paired ICC and adjacent tissues were screened by circRNAs sequencing. To explore the impact of circRNAs on ICC development, experiments involving gain and loss of function were conducted. Various experimental techniques, including quantitative real-time PCR (qPCR), western blotting, RNA immunoprecipitation (RIP), luciferase reporter assays, RNA pull-down, chromatin immunoprecipitation (ChIP), ubiquitination assays and so on were employed to identify the molecular regulatory role of circRNAs. RESULTS: Herein, we reported a new circRNA, which originates from exon 9 to exon 15 of the SLCO1B3 gene (named circSLCO1B3), orchestrated ICC progression by promoting tumor proliferation, metastasis and immune evasion. We found that the circSLCO1B3 gene was highly overexpressed in ICC tissues and related to lymphatic metastasis, tumor sizes, and tumor differentiation. Mechanically, circSLCO1B3 not only promoted ICC proliferation and metastasis via miR-502-5p/HOXC8/SMAD3 axis, but also eradicated anti-tumor immunity via suppressing ubiquitin-proteasome-dependent degradation of PD-L1 by E3 ubiquitin ligase SPOP. We further found that methyltransferase like 3 (METTL3) mediated the m6A methylation of circSLCO1B3 and stabilizes its expression. Our findings indicate that circSLCO1B3 is a potential prognostic marker and therapeutic target in ICC patients. CONCLUSIONS: Taken together, m6A-modified circSLCO1B3 was correlated with poor prognosis in ICC and promoted ICC progression not only by enhancing proliferation and metastasis via potentiating HOXC8 expression, but also by inducing immune evasion via antagonizing PD-L1 degradation. These results suggest that circSLCO1B3 is a potential prognostic marker and therapeutic target for ICC.

Identification and validation of a lactate metabolism-related six-gene prognostic signature in intrahepatic cholangiocarcinoma.

PURPOSE: Intrahepatic cholangiocarcinoma (iCCA) is a highly malignant and fatal liver tumor with increasing incidence worldwide. Lactate metabolism has been recently reported as a crucial contributor to tumor progression and immune regulation in the tumor microenvironment. However, it remains poorly identified about the biological functions of lactate metabolism in iCCA, which hinders the development of prognostic tools and therapeutic interventions. METHODS: The univariate Cox regression analysis and Boruta algorithm were utilized to identify key lactate metabolism-related genes (LMRGs), and a prognostic signature was constructed based on LMRG scores. Genomic variations and immune cell infiltration were evaluated in the high and low LMRG score groups. Finally, the biological functions of key LMRGs were verified with in vitro and in vivo experiments. RESULTS: Patients in the high LMRG score group exhibit a poor prognosis compared to those in the low LMRG score group, with a high frequency of TP53 and KRAS mutations. Moreover, the infiltration and function of NK cells were compromised in the high LMRG score group, consistent with the results from two independent single-cell RNA sequencing datasets and immunohistochemistry of tissue microarrays. Experimental data revealed that lactate dehydrogenase A (LDHA) knockdown inhibited proliferation and migration in iCCA cell lines and tumor growth in immunocompetent mice. CONCLUSION: Our study revealed the biological roles of LDHA in iCCA and developed a reliable lactate metabolism-related prognostic signature for iCCA, offering promising therapeutic targets for iCCA in the clinic.