Cholangiocarcinoma Growth Research Articles

Glycerophospholipid-driven lipid metabolic reprogramming as a common key mechanism in the progression of human primary hepatocellular carcinoma and cholangiocarcinoma

Metabolic reprogramming, a key mechanism regulating the growth and recurrence of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), still lacks effective clinical strategies for its integration into the precise screening of primary liver cancer. This study utilized ultra-high-performance liquid chromatography with quadrupole time-of-flight mass spectrometry to conduct a comprehensive, non-targeted metabolomics analysis, revealing significant upregulation of lipid metabolites such as phosphatidylcholine and lysophosphatidylcholine in patients with HCC and CCA, particularly within the glycerophospholipid metabolic pathway. Hematoxylin and eosin and immunohistochemical staining demonstrated marked upregulation of phospholipase A2 in tumor tissues, further emphasizing the potential of lipid metabolism as a therapeutic target and its important part in the course of cancer. This work provides a new viewpoint for addressing the clinical challenges associated with HCC and CCA, laying the groundwork for the broad application of early diagnosis and personalized treatment strategies, and ultimately aiming to provide tailored and precise therapeutic options for patients.

RBM39 Enhances Cholangiocarcinoma Growth Through EZH2-mediated WNT7B/β-catenin Pathway

Background and aimsThe RNA-binding motif protein 39 (RBM39) functions as both an RNA-binding protein and a splicing factor in a variety of cancer types. However, the function of RBM39 in cholangiocarcinoma (CCA) remains undefined. In this study, we aimed to investigate the role of RBM39 in CCA and explore its potential as a therapeutic target. MethodsThe expression of RBM39 in CCA was investigated by analyzing human CCA tumor specimens. CRISPR/Cas9 or shRNA-mediated depletion of RBM39 was performed in vitro and in vivo to document the oncogenic role of RBM39 in CCA. The anti-tumor effect of the RBM39 inhibitor Indisulam in combination with the EZH2 degrader MS177 was assessed in vitro and in vivo. ResultsRBM39 is significantly increased in human CCA tissues and associated with a poor prognosis in CCA patients. Depletion of RBM39 by CRISPR/Cas9 or shRNA inhibited CCA cell proliferation in vitro and prevented CCA development and tumor growth in mice. Mechanistically, our results showed that depletion of RBM39 suppressed EZH2 expression via disrupting its mRNA splicing. RBM39-regulated EZH2 controls WNT7B/β-catenin activity. Pharmacological co-targeting of RBM39 (with Indisulam) and EZH2 (with MS177) resulted in a synergistic antitumor effect, both in vitro and in vivo. ConclusionThis study discloses a novel RBM39-EZH2-β-catenin signaling axis that is crucial for CCA growth. Our findings suggest that simultaneous inhibition of RBM39 and EZH2 presents a promising therapeutic strategy for CCA treatment.

Targeting USP7 to induce ubiquitination degradation of oncogenic ATAD2 and effects on cholangiocarcinoma growth.

e16215 Background: Cholangiocarcinoma (CCA) is a highly fatal disease due to limited therapeutic targets. Deubiquitinase USP7 is an oncogene and has been suggested to be deeply involved in regulating tumor initiation and progression, but its abundance and role in CCA still remain unclear. Methods: USP7 mRNA expression was performed using TCGA and GEO database. Survival analysis in CCA patients with high- and low-USP7 mRNA expression was performed using NODE database. CCK8, colony formation, flow cytometry and shRNA interference assay were used to evaluate the biological function of USP7-ATAD2 axis on CCA cancer cells in vitro. 4D label-free quantification proteomics was used to analyze the targets and networks regulated by USP7. The molecular mechanism of USP7 and ATAD2 in CCA was determined by conducting Western blot, co-immunoprecipitation, IHC and quantitative real-time PCR (qPCR) analyses. The CCA PDX model was used to evaluate the efficacy of targeting USP7 in the treatment of cholangiocarcinoma. Results: Here, we found USP7 is highly expressed in CAA, and is associated with poor outcomes of CCA patients. We show that USP7 depletion induces S phase arrest, and suppresses CCA tumor cells proliferation. Next, we provide a comprehensive understanding of targets and networks affected by USP7 depletion by performing a 4D label-free quantification proteomics analysis. We show that ATAD2 is a USP7 target, and USP7 interacts with and deubiquitinates ATAD2 to stabilize ATAD2 protein level. Ectopic expression of ATAD2 in USP7-depleted cells rescues the cell proliferation phenotype. Further, pharmacological blocking the activity of USP7 by P5091 inhibits tumor growth in CCA patient-derived xenograft (PDX) mouse model. Conclusions: This study uncovers the role of USP7-ATAD2 axis in regulating tumor growth, and targeting USP7 may provide a novel therapeutic strategy for CCA.

Photodynamic therapy inhibits cancer progression and induces ferroptosis and apoptosis by targeting P53/GPX4/SLC7A11 signaling pathways in cholangiocarcinoma

BackgroundCholangiocarcinoma (CCA) is a malignant tumor with a poor prognosis. The specific mechanism of photodynamic therapy (PDT) in treating CCA remains unclear. This study aims to investigate the mechanisms of PDT in the treatment of CCA and try to improve the therapeutic effect of PDT by intervening associated signaling pathways. MethodsThe Cell Counting Kit-8 (CCK-8) was used to examine the cytotoxicity of CCA cell lines following PDT. Apoptosis and reactive oxygen species (ROS) levels were measured by flow cytometry. A transmission electron microscope was used to study the changes in cell mitochondria after PDT. The levels of glutathione (GSH), malondialdehyde (MDA), ferrous iron (Fe2+), lactate dehydrogenase (LDH), and lipid peroxide (LPO) were determined. Changes in the expression of apoptosis and ferroptosis-related proteins were determined using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. Xenograft tumor models were developed to investigate the effects of PDT on tumor proliferation, apoptosis, and ferroptosis in vivo. ResultsPDT inhibited tumor proliferation and induced apoptosis both in vivo and in vitro. This treatment led to swelling and damage of the mitochondria in affected cells. Furthermore, ROS levels rose, accompanied by an increase in the proportion of apoptotic-positive cells. The expressions of Bax and Caspase-3 were upregulated, while the Bcl-2 was downregulated. Meanwhile, PDT triggered ferroptosis, marked by decreased expressions of GPX4 and SLC7A11, and reduced GSH levels. This was accompanied by upregulation of P53 expression and heightened levels of Fe2+, LPO, MDA, and LDH. After inducing the ferroptosis pathway, the therapeutic effect of PDT was enhanced, the tumor tissue was further reduced, and the degree of malignancy was reduced. ConclusionPDT promotes apoptosis and ferroptosis of cholangiocarcinoma cells by activating the P53/SLC7A11/GPX4 signaling pathway and inhibits the growth of cholangiocarcinoma. Inducing ferroptosis can enhance the effectiveness of photodynamic therapy.

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

BackgroundCholangiocarcinoma (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.MethodsThe 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.ResultsWe 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.ConclusionsThis 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.

FATP5 Is Indispensable for the Growth of Intrahepatic Cholangiocarcinoma.

This study provides the first in vivo evidence that FATP5 is a potential therapeutic target for treating ICC.

Overexpression of microRNA-205-5p promotes cholangiocarcinoma growth by reducing expression of homeodomain-interacting protein kinase 3

The microRNA miR-205-5p has diverse effects in different malignancies, including cholangiocarcinoma (CCA), but its effects on CCA progression is unclear. Here we investigated the role and function of miR-205-5p in CCA. Three CCA cell lines and human serum samples were found to have much higher expression levels of miR-205-5p than seen in typical cholangiocyte cell lines and healthy controls. Inhibition of miR-205-5p suppressed CCA cell motility, invasion and proliferation of KKU-213B whereby overexpression of miR-205-5p promoted cell proliferation and motility of KKU-100 cells. Bioinformatics tools (miRDB, TargetScan, miRWalk, and GEPIA) all predicted various miR-205-5p targets. Experiments using miR-205-5p inhibitor and mimic indicated that homeodomain-interacting protein kinase 3 (HIPK3) was a potential direct target of miR-205-5p. Overexpression of HIPK3 using HIPK3 plasmid cloning DNA suppressed migration and proliferation of KKU-100 cells. Notably, HIPK3 expression was lower in human CCA tissues than in normal adjacent tissues. High HIPK3 expression was significantly associated with longer survival time of CCA patients. Multivariate regression analysis indicated tissue HIPK3 levels as an independent prognostic factor for CCA patients. These findings indicate that overexpression of miR-205-5p promotes CCA cells proliferation and migration partly via HIPK3-dependent way. Therefore, targeting miR-205-5p may be a potential treatment approach for CCA.

The RNA methyltransferase METTL16 enhances cholangiocarcinoma growth through PRDM15-mediated FGFR4 expression

BackgroundRNA N6-Methyladenosine (m6A) modification is implicated in the progression of human cancers including cholangiocarcinoma (CCA). METTL16 is recently identified as a new RNA methyltransferase responsible for m6A modification, although the role of METTL16 in CCA has not yet been examined. The current study aims to investigate the effect and mechanism of the RNA methyltransferase METTL16 in CCA.MethodsThe expression of METTL16 in CCA was examined by analyzing publicly available datasets or by IHC staining on tumor samples. siRNA or CRISPR/Cas9-mediated loss of function studies were performed in vitro and in vivo to investigate the oncogenic role of METTL16 in CCA. MeRIP-Seq was carried out to identify the downstream target of METTL16. ChIP-qPCR, immunoprecipitation, and immunoblots were used to explore the regulation mechanisms for METTL16 expression in CCA.ResultsWe observed that the expression of METTL16 was noticeably increased in human CCA tissues. Depletion of METTL16 significantly inhibited CCA cell proliferation and decreased tumor progression. PRDM15 was identified as a key target of METTL16 in CCA cells. Mechanistically, our data showed that METTL16 regulated PRDM15 protein expression via YTHDF1-dependent translation. Accordingly, we observed that restoration of PRDM15 expression could rescue the deficiency of CCA cell proliferation/colony formation induced by METTL16 depletion. Our subsequent analyses revealed that METTL16-PRDM15 signaling regulated the expression of FGFR4 in CCA cells. Specifically, we observed that PRDM15 protein was associated with the FGFR4 promoter to regulate its expression. Furthermore, we showed that the histone acetyltransferase p300 cooperated with the transcription factor YY1 to regulate METTL16 gene expression via histone H3 lysine 27 (H3K27) acetylation in CCA cells.ConclusionsThis study describes a novel METTL16-PRDM15-FGFR4 signaling axis which is crucial for CCA growth and may have important therapeutic implications. We showed that depletion of METTL16 significantly inhibited CCA cell proliferation and decreased tumor progression.

HS6ST1 overexpressed in cancer-associated fibroblast and inhibited cholangiocarcinoma progression.

Fibroblasts turn into cancer associated fibroblasts (CAFs) in the tumor microenvironment, which play an important role in tumor progression. However, the mechanism is unclear. To investigate the role of CAFs with HS6ST1-overexpression in cell migration and invasion effects. Human primary CAFs were isolated and identified from intrahepatic cholangiocarcinoma. mRNA profiles differences between CAFs and NFs were examined by using transcriptome sequencing. Using Transwell® migration assays, ICCA cells (RBE and HUCCT1) with NF-CM, CAF-CM, CAFsNC-CM, and CAFsHS6ST1-CM were analyzed. Immunohistochemical staining were used to analyze the expression of HS6ST1 in CAF in 152 patients with ICCA. Overall survival (OS) was compared based on CAF HS6ST1 expression were analysed. The relationship between clinicopathological parameters and survival was also examined. Successfully isolated CAFs is positive staining with αSMA, FSP-1, FAP, and PDGFR-β. Transcriptome sequencing showed that differently expressed genes were enriched in the function of the extracellular matrix and chemokine signaling pathway. HS6ST1 is differentially expressed between CAFs and NFs, and associated with the migration and invasion of ICCA cells. Moreover, HS6ST1 positive expression of CAFs predicted unfavorable prognosis in patients with intrahepatic cholangiocarcinoma and showed correlation with the presence of lymph node metastasis. HS6ST1 is new possibilities for targeting the CAFs to reduce cholangiocarcinoma growth and metastasis.

MUC1 induces the accumulation of Foxp3+ Treg cells in the tumor microenvironment to promote the growth and metastasis of cholangiocarcinoma through the EGFR/PI3K/Akt signaling pathway.

Tumor microenvironment (TME) plays an important role in the progression of cholangiocarcinoma. This study aims to explore whether Mucin 1 (MUC1) regulates Foxp3+ Treg cells in the TME of cholangiocarcinoma through the epidermal growth factor receptor (EGFR)/phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathway. High-throughput sequencing dataset in the GEO database combined with GeneCards and Phenolyzer databases was used to obtain key genes in cholangiocarcinoma, followed by downstream pathway prediction. The relationship among MUC1, EGFR, and PI3K/Akt signaling pathway was explored. CD4+ T cells extracted from peripheral blood were induced to differentiate into Treg cells, followed by co-culture with cholangiocarcinoma cells. A mouse model was constructed to detect the role of MUC1 in the accumulation of Foxp3+ Treg cells, malignant phenotypes of cholangiocarcinoma, and tumorigenesis in vivo. MUC1, highly expressed in cholangiocarcinoma, might be involved in cholangiocarcinoma development. MUC1 interacted with the EGFR to activate the EGFR/PI3K/Akt signaling pathway. MUC1 overexpression could activate the EGFR/PI3K/Akt signaling pathway, which promoted the accumulation of Foxp3+ Treg cells in the TME and the malignant phenotypes of cholangiocarcinoma cells both in vitro and in vivo and enhanced tumorigenesis in vivo. MUC1 may interact with EGFR to activate the EGFR/PI3K/Akt signaling pathway, which induces the accumulation of Foxp3+ Treg cells, enhancing the malignant phenotypes of cholangiocarcinoma cells and tumorigenesis in vivo and ultimately augmenting cholangiocarcinoma growth and metastasis.

Exosomal lncRNA HCG18 contributes to cholangiocarcinoma growth and metastasis through mediating miR-424-5p/SOX9 axis through PI3K/AKT pathway

Cholangiocarcinoma is a highly aggressive malignant tumor disease with the increasing incidence and mortality. It’s urgent to identify specific biomarkers for cholangiocarcinoma treatment and diagnosis. Recent studies have noted the importance of lncRNAs in cancer and the following downstream mechanism with miRNAs network has been a hotspot. This work aimed to discover the role of lncRNA HCG18 and its possible downstream mechanism in cholangiocarcinoma tumor progression. Initially, through bioinformatics tools, we observed abnormal expression of lncRNA HCG18 in cholangiocarcinoma. In vitro experiments like (CCK-8, EdU, colony formation, flow cytometry, transwell, wound healing assays) and animal study confirmed that lncRNA HCG18 served as a cancer-promoting gene, promoted cancer proliferation, migration and invasion abilities. Besides, we found cancer cell-secreted exosomes transitted HCG18 to surrounding tumor cells and accelerated tumor growth and metastasis. After that, we confirmed HCG18 directly interacted with miR-424-5p through FISH, RIP and dual luciferase reporter assays with negative modulation. The inhibition of miR-424-5p reversed the HCG18 knockdown induced suppression on cholangiocarcinoma cancer cells. More specific, miR-424-5p targeted to SOX9 contributed to cholangiocarcinoma growth and metastasis through mediating PI3K/AKT pathway. In conclusion, these findings provide solid evidence of lncRNAs/miRNAs regulation in cholangiocarcinoma progression.

Spatiotemporal regulation of cholangiocarcinoma growth and dissemination by peritumoral myofibroblasts in a Vcam1-dependent manner

Intrahepatic cholangiocarcinoma (iCCA) is characterized by its highly desmoplastic stroma. Myofibroblasts (MFs) are present both within the tumor mass (intratumoral MFs, iMFs) and at the tumor border (peritumoral MFs, pMFs). Using a spheroid-based coculture system, we show that the initial iCCA-pMF contact is growth suppressive to the tumor cells. However, prolonged iCCA-pMF interaction elicits significant tumor cell invasion and dissemination. We find that vascular cell adhesion molecule-1 (Vcam1) level is elevated in tumor cells in contact with pMFs but low in disseminated tumor cells both in vitro and in vivo. A gene regulatory network analysis of mouse and patient iCCA tumors and Vcam1 knockout (Vcam1KO) demonstrate a heavy involvement of Vcam1 in epithelial-to-mesenchymal transition. While Vcam1KO has only a limited impact on tumor cell growth in their monoculture, Vcam1KO spheroids exhibit instant dissemination and a severe growth defect when cocultured with pMFs. When transplanted into the liver, Vcam1KO iCCA cells show a similar increase in dissemination but a significant defect in establishing primary and metastatic tumors. Incomplete blocking of Vcam1 in vivo reduces the size but increase the number of metastatic lesions. Overall, our study shows a spatiotemporal regulation of iCCA growth and dissemination by pMFs in a Vcam1-dependent manner.

Elevated ITGA2 expression promotes collagen type I-induced clonogenic growth of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) arises along the peripheral bile ducts and is often accompanied by a tumor microenvironment (TME) high in extracellular matrices (ECMs). In this study, we aimed to evaluate whether an ECM-rich TME favors iCCA progression. We identified ITGA2, which encodes collagen-binding integrin α2, to be differentially-expressed in iCCA tumors compared with adjacent normal tissues. Elevated ITGA2 is also positively-correlated with its ligand, collagen type I. Increased ITGA2 expression and its role in collagen type I binding was validated in vitro using four iCCA cell lines, compared with a non-cancerous, cholangiocyte cell line. Robust interaction of iCCA cells with collagen type I was abolished by either ITGA2 depletion or integrin α2β1-selective inhibitor treatment. In a phenotypic study, collagen type I significantly enhances clonogenic growth of HuCCA-1 and HuCCT-1 cells by three and sixfold, respectively. Inhibition of integrin α2 expression or its activity significantly blocks collagen type I-induced colony growth in both cell lines. Taken together, our data provide mechanistic evidence that collagen type I promotes growth of iCCA colonies through integrin α2 suggesting that the collagen type I—integrin α2 axis could be a promising target for cancer prevention and a therapeutic opportunity for this cancer.

Triptolide inhibits intrahepatic cholangiocarcinoma growth by suppressing glycolysis via the AKT/mTOR pathway

BackgroundHigh levels of glycolysis supply large quantities of energy and biological macromolecular raw materials for cell proliferation. Triptolide (TP) is a kind of epoxy diterpene lactone extracted from the roots, flowers, leaves, or grains of the Celastraceae plant, Tripterygium wilfordii. TP has multiple biological activities, including anti-inflammatory, immunologic suppression, and anti-cancer effects. Nevertheless, it is little known regarding its anti-intrahepatic cholangiocarcinoma (ICC) growth, and the mechanism still require exploration. PurposeThis research explored the effect of TP on ICC growth and investigated whether TP inhibits glycolysis via the AKT/mTOR pathway. MethodsCell proliferation was analyzed by Cell Counting Kit-8 (CCK-8), clonogenic assay, and flow cytometry. The underlying molecular mechanism was identified by determining glucose consumption, ATP production, lactate production, hexokinase (HK) and pyruvate kinase (PK) activity, and Western blot analysis. A rapid ICC model of AKT/YapS127A oncogene coactivation in mice was used to clarify the effect of TP treatment on tumor growth and glycolysis. ResultsThe results showed that TP treatment significantly inhibited ICC cell proliferation and glycolysis in a dose- and time-dependent manner(P < 0.05). Further analysis suggested that TP suppressed ICC cell glycolysis by targeting AKT/mTOR signaling. Additionally, we found that TP inhibits tumor growth and glycolysis in AKT/YapS127A mice(P < 0.05). ConclusionTaken together, we revealed that TP suppressed ICC growth by suppressing glycolysis via the AKT/mTOR pathway and may provide a potential therapeutic target for ICC treatment.

Conjugated Bile Acids Accelerate Progression of Pancreatic Cancer Metastasis via S1PR2 Signaling in Cholestasis.

Pancreatic cancer (PC) has an extremely high mortality rate, where obstructive jaundice due to cholestasis is a classic symptom. Conjugated bile acids (CBAs) such as taurocholic acid (TCA) have been reported to activate both the ERK1/2 and AKT signaling pathways via S1P receptor 2 (S1PR2) and promote growth of cholangiocarcinoma. Thus, we hypothesize that CBAs, which accumulate in cholestasis, accelerate PC progression via S1PR2. Murine Panc02-luc and human AsPC-1, MIA PaCa2, and BxPC-3 cells were treated with TCA, S1PR2 agonist CYM5520, S1PR2 antagonist JTE-013, sphingosine-1-phosphate (S1P), and functional S1P receptor antagonist (except S1PR2) FTY720. Bile duct ligation (BDL) was performed on liver implantation or intraperitoneal injection of Panc02-luc cells. Panc02-luc and AsPC-1 cells predominantly expressed S1PR2, and their growth and migration were stimulated by TCA or CYM5520 in dose-dependent manner, which was blocked by JTE-013. This finding was not seen in PC cell lines expressing other S1P receptors than S1PR2. Panc02-luc growth stimulation by S1P was not blocked by FTY720. BDL significantly increased PC liver metastasis compared with sham. PC peritoneal carcinomatosis was significantly worsened by BDL, confirmed by number of nodules, tumor weight, bioluminescence, Ki-67 stain, ascites, and worse survival compared with sham. CYM5520 significantly worsened PC carcinomatosis, whereas treatment with anti-S1P antibody or FTY720 also worsened progression. CBAs accelerated growth of S1PR2 predominant PC both in vitro and in vivo. This finding implicates S1PR2 as a potential therapeutic target in metastatic S1PR2 predominant pancreatic cancer.

Circ_0000284 facilitates the growth, metastasis and glycolysis of intrahepatic cholangiocarcinoma through miR-152-3p-mediated PDK1 expression.

Circular RNAs (circRNAs) are key molecules in the regulation of intrahepatic cholangiocarcinoma (ICC) progression. The purpose of this study was to analyze the function and underlying molecular mechanism of circ_0000284 in ICC. Quantitative real-time PCR was used to analyze the circ_0000284, microRNA (miR)-152-3p and pyruvate dehydrogenase kinase 1 (PDK1) expression. Cell proliferation, apoptosis, invasion and migration were executed by cell counting kit 8 assay, EdU assay, flow cytometry, transwell assay and wound healing assay, respectively. All protein expression levels were examined using western blot analysis. Cell glycolysis was analyzed by detecting glucose consumption, lactate production and ATP/ADP ratios. Target relationship was estimated by dual-luciferase reporter assay. The effect of circ_0000284 on ICC tumor growth in vivo was evaluated by constructing xenograft mice model. We detected high expression of circ_0000284 in ICC tumor tissues and cells. Downregulated circ_0000284 inhibited ICC cell proliferation, invasion, migration, glycolysis, and accelerated apoptosis. MiR-152-3p was sponged by circ_0000284, and its inhibitor revoked the effect of circ_0000284 knockdown on ICC cell progression. PDK1 was a target of miR-152-3p, and its expression was suppressed by circ_0000284 knockdown. PDK1 overexpression reversed the inhibition effect of miR-152-3p on ICC cell growth, metastasis and glycolysis. In animal experiments, circ_0000284 downregulation also inhibited ICC tumor growth. Circ_0000284 promoted the growth, metastasis and glycolysis of ICC by miR-152-3p/PDK1 pathway, showing that circ_0000284 was a potential therapeutic target for ICC.

Inhibition of 14-3-3ε by K50 acetylation activates YAP1 to promote cholangiocarcinoma growth

14-3-3 proteins are ubiquitous adapters combining with phosphorylated serine/threonine motifs to regulate multiple cellular processes. As a negative regulator, 14-3-3 proteins could sequester the phosphorylated YAP1 in cytoplasm to inhibit its activity. In this study, we identified the K50 acetylation (K50ac) of 14-3-3ε protein and investigated its roles and mechanism in cholangiocarcinoma progression. The NAD (+)-dependent protein deacetylases inhibitor, NAM treatment significantly up-regulated the K50ac of 14-3-3ε. K50R mutation resulted in the decrease of K50ac of 14-3-3ε. The K50ac of 14-3-3ε was reversibly mediated by PCAF acetyltransferase and sirt1 deacetylases. K50ac had no obvious effect on the protein stability of 14-3-3ε, but inhibited the combination of 14-3-3ε with phosphorylated YAP1, which resulted in the activation of YAP1 in cholangiocarcinoma. K50R significantly decreased cholangiocarcinoma cell proliferation in vitro and the growth of tumor xenograft in vivo compared with WT (wild type) 14-3-3ε. The level of K50ac were higher in cholangiocarcinoma tissues accompanied by the accumulation of YAP1 in nuclear than para-carcinoma tissues. Our study revealed the underlying mechanism of K50ac of 14-3-3ε and its roles in cholangiocarcinoma, providing a potential targeting for cholangiocarcinoma therapy.

Chimeric immune checkpoint protein vaccines inhibit the tumorigenesis and growth of rat cholangiocarcinoma

Cholangiocarcinoma (CCA) isthe second most common primary liver malignancy and carries a dismal prognosis due to difficulties in achieving an optimal resection, and poor response to current standard-of-care systemic therapies. We previously devised a CTLA4-PD-L1 DNA cancer vaccine (DNA vaccine) and demonstrated its therapeutic effects on reducing tumor growth in a thioacetamide (TAA)-induced rat intrahepatic CCA (iCCA) model. Here, we developed a CTLA4-PD-L1 chimeric protein vaccine (Protein vaccine), and examined its effects in the rat iCCA model. In a therapeutic setting, iCCA-bearing rats received either DNA plus Protein vaccines or Protein vaccine alone, resulting in increased PD-L1 and CTLA-4 antibody titers, and reduced iCCA tumor burden as verified by animal positron emission tomography (PET) scans. Treating iCCA-bearing rats with Protein vaccine alone led to the increase of CTAL4 antibody titers that correlated with the decrease of tumor SUV ratio, indicating regressed tumor burden, along with increased &lt;i&gt;CD8&lt;/i&gt; and granzyme A (&lt;i&gt;GZMA&lt;/i&gt;) expression, anddecreased PD-L1 expression on tumor cells. In a preventive setting,DNA or Protein vaccines were injected in rats before the induction of iCCA by TAA. Protein vaccines induced a more sustained PD-L1 and CTLA-4 antibody titers compared with DNA vaccines, and was more potent in preventing iCCA tumorigenesis. Correspondingly, Protein vaccines, but not DNA vaccines, downregulated PD-L1 gene expression and hindered the carcinogenesis of iCCA. Taken together, the CTLA4-PD-L1 chimeric proteinvaccine may function both as a therapeuticcancer vaccine andas a preventive cancer vaccine in theTAA-induced iCCA rat model.

Brusatol suppresses the growth of intrahepatic cholangiocarcinoma by PI3K/Akt pathway

BackgroundIntrahepatic cholangiocarcinoma (ICC) is a malignancy with a hidden onset, high metastasis recurrence rate, and poor prognosis. Research on effective drugs for ICC is important for improving the prognosis of patients in the clinic. Brusatol is a quassinoid extracted from the seeds of Brucea sumatrana and has been shown to have the potential to inhibit tumor metastasis and proliferation. There has been no scientific research on the therapeutic effect of brusatol on ICC. Our study offers a novel strategy for the therapy of ICC. PurposeExplore effects of brusatol treatment on ICC and clarify the possible mechanism. Study DesignVarious cell functional experiments and basic experimental techniques were applied to ICC cell lines to explore the influences of brusatol on ICC cells; this conclusion was further verified in animal models. MethodsThe anti-cancer effects of the drug on the cell, protein, and RNA level were verified by cell functional experiments, WB blotting and transcriptome sequencing experiments, respectively. Finally, the experimental results were verified using subcutaneous tumor experiments in nude mice. ResultsThe consequences exhibited that the levels of epithelial markers of ICC cells increased after brusatol treatment, and the levels of interstitial indicators decreased, suppressing the epithelial-mesenchymal transition (EMT) process. Brusatol inhibited proliferation, induced apoptosis, and suppressed the migration and invasion abilities of Hucc-T1 and RBE oncocytes via activating PI3K/Akt pathway. It also suppressed the growth of Hucc-T1 xenografts in nude mice. ConclusionBrusatol inhibits the proliferation and EMT process in ICC oncocytes by the PI3K/Akt pathway and promotes apoptosis in oncocytes.

Abstract 1573: Paradoxical roles of peritumoral myofibroblasts in intrahepatic cholangiocarcinoma growth and metastasis

Abstract Background and Rationale: Intrahepatic cholangiocarcinoma (iCCA) is an aggressive type of primary liver cancer characterized by its highly desmoplastic stroma. Compared to the ample knowledge on the protumorigenic functions of iCCA intratumoral myofibroblasts (iMFs), little is known about the activation status of MFs in the tumor-surrounding liver (peritumoral myofibroblasts, pMFs) and their potential role in iCCA development. Results: We examined MF activation in both patient iCCA tumors and an iCCA orthotopic allograft mouse model. We found there was a significant, tumor-induced activation and accumulation of pMFs at the tumor border. Using an in vitro spheroid coculture system, we confirmed that iCCA-liver interaction induced rapid pMF activation at their interface. We found that MFs mixed within tumor spheroids as iMFs had a pro-proliferative effect on iCCA tumor cells similar to the previous reports. However, when the same MFs were seeded around iCCA spheroids as pMFs, they exerted a strong suppressive effect on tumor cells growth. Interestingly, prolonged iCCA-pMF coculture elicited marked tumor cell invasion and dissemination which did not occur in iCCA-iMF coculture. We found vascular cell adhesion protein 1 (Vcam1), a glycoprotein that has been implicated in solid tumor metastasis, was part of the dynamic regulation of tumor cell behaviors by iCCA-pMF interaction. Vcam1 was upregulated in the tumor cells at the early, growth-suppressing phase of iCCA-pMF interaction both in vitro and in vivo, and was then downregulated in tumor cells when they started to disseminate. Systemic blocking of Vcam1 activity in iCCA allograft mouse models using a Vcam1 neutralizing antibody slowed the primary tumor growth but promoted tumor cell dissemination. Conclusion: Our data suggest that pMFs are beyond simple pro- or anti-tumorigenic in iCCA development. iCCA development induces rapid activation and accumulation of pMFs at the tumor border which suppress tumor growth at early stage but eventually elicit tumor cell dissemination at late stage. Citation Format: Cheng Tian, Liyuan Li, Yizhen Li, Wentao Yang, Li Fan, Anthony Brown, Michelle Morrison, Jun J. Yang, Evan S. Glazer, Liqin Zhu. Paradoxical roles of peritumoral myofibroblasts in intrahepatic cholangiocarcinoma growth and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1573.