Neoadjuvant therapy leads to objective response in intrahepatic cholangiocarcinoma

BACKGROUND

Intrahepatic cholangiocarcinoma (iCCA) is the second most common hepatic malignancy and has a poor prognosis. Surgical resection is the standard of care for patients with resectable disease, representing 30-40% of cases. Increasingly, neoadjuvant systemic therapy is being utilized in patients due to high-risk anatomic or biologic considerations. However, data on the clinical effect of this approach are limited. We performed a cohort study to evaluate the effect of neoadjuvant therapy in patients with oncologically high-risk iCCA.

METHODS

iCCA patients (n = 181) between the years 2014-2020 were reviewed for clinical, histopathologic, treatment, and outcome-related data. Tumor regression grade was scored per CAP criteria for gastrointestinal carcinomas.

RESULTS

47 iCCA patients received neoadjuvant therapy and 72 did not. Neoadjuvant treatment led to objective response and tumor regression by CAP score. After adjustment for age, clinical stage, and tumor size, the outcomes of patients who had neoadjuvant therapy followed by surgery were not significantly different from those patients who had surgery first.

DISCUSSION

In conclusion, neoadjuvant therapy in iCCA facilitated surgical care. The progression-free and overall survival for surgical patients with and without neoadjuvant therapy were not significantly different suggesting this approach needs further exploration as an effective treatment paradigm.

Syngeneic murine models with distinct immune microenvironments represent subsets of human intrahepatic cholangiocarcinoma

BACKGROUND & AIMS

Cholangiocarcinoma (CCA) is a poorly immunogenic malignancy associated with limited survival. Syngeneic immunocompetent mouse models of CCA are an essential tool to elucidate the tumor immune microenvironment (TIME), understand mechanisms of tumor immune evasion, and test novel immunotherapeutic strategies. The scope of this study was to develop and characterize immunocompetent CCA models with distinct genetic drivers, and correlate tumor genomics, immunobiology, and therapeutic response.

METHODS

A multifaceted approach including scRNA-seq, CITE-seq, whole exome and bulk RNA sequencing was employed. FDA-approved PD-1/PD-L1 antibodies were tested in humanized PD-1/PD-L1 mice (HuPD-H1).

RESULTS

A genetic mouse model of intrahepatic CCA (iCCA) driven by intrabiliary transduction of Fbxw7ΔF/Akt that mimics human iCCA was generated. From the Fbxw7ΔF/Akt tumors, a murine cell line (FAC) and syngeneic model with genetic and phenotypic characteristics of human iCCA were developed. Established SB1 (YAPS127A/Akt) and KPPC (KrasG12Dp53L/L) models were compared to the FAC model. Although the models had transcriptomic similarities, they had substantial differences as well. Mutation patterns of FAC, SB1, and KPPC cells matched different mutational signatures in Western and Japanese CCA patient cohorts. KPPC tumors had a high tumor mutation burden. FAC tumors had a T cell-infiltrated TIME, while SB1 tumors had a preponderance of suppressive myeloid cells. FAC, SB1, and KPPC tumors matched different immune signatures in human iCCA cohorts. Moreover, FAC, SB1, and KPPC tumor-bearing HuPD-H1 mice displayed differential responses to nivolumab or durvalumab.

CONCLUSIONS

Syngeneic iCCA models display a correlation between tumor genotype and TIME phenotype, with differential responses to FDA-approved immunotherapies. This study underscores the importance of leveraging multiple preclinical models to understand responses to immunotherapy in different genetic subsets of human CCA.

IMPACT AND IMPLICATIONS

Understanding the relationship between tumor genotype and the phenotype of the immune microenvironment is an unmet need in cholangiocarcinoma (CCA). Herein, we use syngeneic murine models of intrahepatic CCA with different genetic drivers to demonstrate a correlation between tumor genotype and immune microenvironment phenotype in murine models, which is associated with differential responses to FDA-approved immunotherapies. This information will help guide other preclinical studies. Additionally, it emphasizes that immune checkpoint inhibition in patients with CCA is not a "one-size-fits-all" approach. Our observations suggest that, as for targeted therapies, patients should be stratified and selected for treatment according to their tumor genetics.

PTEN Deficiency Induces an Extrahepatic Cholangitis-Cholangiocarcinoma Continuum via Aurora kinase A in Mice

BACKGROUND & AIMS

The PTEN-AKT pathway is frequently altered in extrahepatic cholangiocarcinoma (eCCA). We aim to evaluate the role of PTEN in the pathogenesis of eCCA and find novel therapies for this disease.

METHODS

The Pten gene in the biliary epithelial cells were genetically deleted using the Cre-loxp system. The pathologies were evaluated both macroscopically and histologically. The characteristics were further analyzed by immunohistochemistry (IHC), RT-PCR, cell culture, and RNAseq. Some features were compared to those in human eCCA samples. Further mechanistic studies utilized the conditional knockout of Trp53 and Aurora kinase A (Aurka) genes. Experimental therapy was tested using an Aurka inhibitor.

RESULTS

We observed that genetic deletion of the Pten gene in the extrahepatic biliary epithelium and peri-ductal glands initiated sclerosing cholangitis-like lesions in mice, resulting in enlarged and distorted extrahepatic bile ducts in mice as early as one month old. Histologically, these lesions exhibited increased epithelial proliferation, inflammatory cell infiltration, and fibrosis. With aging, the lesions progressed from low-grade dysplasia to invasive carcinoma. Trp53 inactivation further accelerated the disease progression, potentially through downregulating senescence. Further mechanistic studies showed that both human and mouse eCCA showed high expressions of AURKA. Notably, the genetic deletion of Aurka completely eliminated Pten deficiency-induced extrahepatic bile duct lesions. Furthermore, pharmacological inhibition of Aurka alleviated disease progression.

CONCLUSIONS

Pten deficiency in extrahepatic cholangiocytes and peribiliary glands led to a cholangitis-to-cholangiocarcinoma continuum through an Aurka-dependent manner. These findings offer new insights into preventive and therapeutic interventions for extrahepatic CCA.

IMPACT AND IMPLICATIONS

The aberrant PTEN-PI3K-AKT signaling pathway is commonly observed in human extrahepatic cholangiocarcinoma (eCCA), a disease with a poor prognosis. In our study, we developed a mouse model mimicking cholangitis to eCCA progression by conditionally deleting the Pten gene via Pdx1-Cre in epithelial cells and peribiliary glands of the extrahepatic biliary duct. The conditional Pten deletion in these cells led to cholangitis, which gradually advanced to dysplasia, ultimately resulting in eCCA. The loss of Pten heightened Akt signaling, cell proliferation, inflammation, fibrosis, DNA damage, epigenetic signaling, epithelial-mesenchymal transition (EMT), cell dysplasia, and cellular senescence. Genetic deletion or pharmacological inhibition of Aurka successfully halted the disease progression. This model shall be valuable for testing novel therapies and unraveling the mechanisms of eCCA tumorigenesis.

Macrophage RAGE activation is proinflammatory in NASH

Intrahepatic macrophages in nonalcoholic steatohepatitis (NASH) are heterogenous and include proinflammatory recruited monocyte-derived macrophages. The receptor for advanced glycation endproducts (RAGE) is expressed on macrophages and can be activated by damage associated molecular patterns (DAMPs) upregulated in NASH, yet the role of macrophage-specific RAGE signaling in NASH is unclear. Therefore, we hypothesized that RAGE-expressing macrophages are proinflammatory and mediate liver inflammation in NASH. Compared with healthy controls, RAGE expression was increased in liver biopsies from patients with NASH. In a high-fat, -fructose, and -cholesterol-induced (FFC)-induced murine model of NASH, RAGE expression was increased, specifically on recruited macrophages. FFC mice that received a pharmacological inhibitor of RAGE (TTP488), and myeloid-specific RAGE KO mice (RAGE-MKO) had attenuated liver injury associated with a reduced accumulation of RAGE+ recruited macrophages. Transcriptomics analysis suggested that pathways of macrophage and T cell activation were upregulated by FFC diet, inhibited by TTP488 treatment, and reduced in RAGE-MKO mice. Correspondingly, the secretome of ligand-stimulated BM-derived macrophages from RAGE-MKO mice had an attenuated capacity to activate CD8+ T cells. Our data implicate RAGE as what we propose to be a novel and potentially targetable mediator of the proinflammatory signaling of recruited macrophages in NASH.

Noncanonical TRAIL Signaling Promotes Myeloid-Derived Suppressor Cell Abundance and Tumor Growth in Cholangiocarcinoma

BACKGROUND & AIMS

Proapoptotic tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) signaling as a cause of cancer cell death is a well-established mechanism. However, TRAIL-receptor (TRAIL-R) agonists have had very limited anticancer activity in human beings, challenging the concept of TRAIL as a potent anticancer agent. Herein, we aimed to define mechanisms by which TRAIL+ cancer cells can leverage noncanonical TRAIL signaling in myeloid-derived suppressor cells (MDSCs) promoting their abundance in murine cholangiocarcinoma (CCA).

METHODS

Multiple immunocompetent syngeneic, orthotopic models of CCA were used. Single-cell RNA sequencing and cellular indexing of transcriptomes and epitopes by sequencing of CD45+ cells in murine tumors from the different CCA models was conducted.

RESULTS

In multiple immunocompetent murine models of CCA, implantation of TRAIL+ murine cancer cells into Trail-r-/- mice resulted in a significant reduction in tumor volumes compared with wild-type mice. Tumor-bearing Trail-r-/- mice had a significant decrease in the abundance of MDSCs owing to attenuation of MDSC proliferation. Noncanonical TRAIL signaling with consequent nuclear factor-κB activation in MDSCs facilitated enhanced MDSC proliferation. Single-cell RNA sequencing and cellular indexing of transcriptomes and epitopes by sequencing of immune cells from murine tumors showed enrichment of a nuclear factor-κB activation signature in MDSCs. Moreover, MDSCs were resistant to TRAIL-mediated apoptosis owing to enhanced expression of cellular FLICE inhibitory protein, an inhibitor of proapoptotic TRAIL signaling. Accordingly, cellular FLICE inhibitory protein knockdown sensitized murine MDSCs to TRAIL-mediated apoptosis. Finally, cancer cell-restricted deletion of Trail significantly reduced MDSC abundance and murine tumor burden.

CONCLUSIONS

Our findings highlight the therapeutic potential of targeting TRAIL+ cancer cells for treatment of a poorly immunogenic cancer.

IL-17 Signaling in Primary Sclerosing Cholangitis Patient-Derived Organoids

The pathogenesis of primary sclerosing cholangitis (PSC) is unclear, although studies implicate IL-17A as an inflammatory mediator in this disease. However, a direct assessment of IL-17 signaling in PSC cholangiocytes is lacking. In this study we aimed to investigate the response of PSC extrahepatic cholangiocyte organoids (ECO) to IL-17A stimulation. Cholangiocytes obtained from PSC and non-PSC patients by endoscopic retrograde cholangiography (ERC) were cultured as ECO. The ECO were treated with vehicle or IL-17A and assessed by transcriptomics, secretome analysis, and genome sequencing (GS). Unsupervised clustering of all integrated scRNA-seq data identified 8 cholangiocyte clusters which did not differ between PSC and non-PSC ECO. However, PSC ECO cells demonstrated a robust response to IL-17 treatment, noted by an increased number of differentially expressed genes (DEG) by transcriptomics, and more abundant chemokine and cytokine expression and secretion. After rigorous filtering, GS identified candidate somatic variants shared among PSC ECO from unrelated individuals. However, no candidate rare variants in genes regulating the IL-17 pathway were identified, but rare variants regulating the MAPK signaling pathway were present in all PSC ECO. In conclusion, PSC and non-PSC patient derived ECO respond differently to IL-17 stimulation implicating this pathway in the pathogenesis of PSC.

Immunobiology of cholangiocarcinoma

Recent literature has significantly advanced our knowledge and understanding of the tumour immune microenvironment of cholangiocarcinoma. Detailed characterisation of the immune landscape has defined new patient subtypes. While not utilised in clinical practice yet, these novel classifications will help inform decisions regarding immunotherapeutic approaches. Suppressive immune cells, such as tumour-associated macrophages and myeloid-derived suppressor cells, form a barrier that shields tumour cells from immune surveillance. The presence of this immunosuppressive barrier in combination with a variety of immune escape mechanisms employed by tumour cells leads to poor tumour immunogenicity. Broad strategies to re-equip the immune system include blockade of suppressive immune cell recruitment to priming cytotoxic effector cells against tumour antigens. While immunotherapeutic strategies are gaining traction for the treatment of cholangiocarcinoma, there is a long road of discovery ahead in order to make meaningful contributions to patient therapy and survival.

Noncanonical TRAIL Signaling Promotes Myeloid-Derived Suppressor Cell Abundance and Tumor Progression in Cholangiocarcinoma

Proapoptotic tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) signaling as a cause of cancer cell death is a well-established mechanism. However, TRAIL-receptor (TRAIL-R) agonists have had very limited anticancer activity in humans, challenging the concept of TRAIL as a potent anticancer agent. Herein, we demonstrate that TRAIL + cancer cells can leverage noncanonical TRAIL signaling in myeloid-derived suppressor cells (MDSCs) promoting their abundance in murine cholangiocarcinoma (CCA). In multiple immunocompetent syngeneic, orthotopic murine models of CCA, implantation of TRAIL + murine cancer cells into Trail-r -/- mice resulted in a significant reduction in tumor volumes compared to wild type mice. Tumor bearing Trail-r -/- mice had a significant decrease in the abundance of MDSCs due to attenuation of MDSC proliferation. Noncanonical TRAIL signaling with consequent NF-κB activation in MDSCs facilitated enhanced MDSC proliferation. Single cell RNA sequencing and cellular indexing of transcriptomes and epitopes by sequencing (CITE-Seq) of CD45 + cells in murine tumors from three distinct immunocompetent CCA models demonstrated a significant enrichment of an NF-κB activation signature in MDSCs. Moreover, MDSCs were resistant to TRAIL-mediated apoptosis due to enhanced expression of cellular FLICE inhibitory protein (cFLIP), an inhibitor of proapoptotic TRAIL signaling. Accordingly, cFLIP knockdown sensitized murine MDSCs to TRAIL-mediated apoptosis. Finally, cancer cell-restricted deletion of Trail significantly reduced MDSC abundance and murine tumor burden. In summary, our findings define a noncanonical TRAIL signal in MDSCs and highlight the therapeutic potential of targeting TRAIL + cancer cells for the treatment of a poorly immunogenic cancer.

EASL-ILCA Clinical Practice Guidelines on the management of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) develops inside the liver, between bile ductules and the second-order bile ducts. It is the second most frequent primary liver cancer after hepatocellular carcinoma, and its global incidence is increasing. It is associated with an alarming mortality rate owing to its silent presentation (often leading to late diagnosis), highly aggressive nature and resistance to treatment. Early diagnosis, molecular characterisation, accurate staging and personalised multidisciplinary treatments represent current challenges for researchers and physicians. Unfortunately, these challenges are beset by the high heterogeneity of iCCA at the clinical, genomic, epigenetic and molecular levels, very often precluding successful management. Nonetheless, in the last few years, progress has been made in molecular characterisation, surgical management, and targeted therapy. Recent advances together with the awareness that iCCA represents a distinct entity amongst the CCA family, led the ILCA and EASL governing boards to commission international experts to draft dedicated evidence-based guidelines for physicians involved in the diagnostic, prognostic, and therapeutic management of iCCA.

Cholangiocarcinoma - novel biological insights and therapeutic strategies

In the past 5 years, important advances have been made in the scientific understanding and clinical management of cholangiocarcinoma (CCA). The cellular immune landscape of CCA has been characterized and tumour subsets with distinct immune microenvironments have been defined using molecular approaches. Among these subsets, the identification of 'immune-desert' tumours that are relatively devoid of immune cells emphasizes the need to consider the tumour immune microenvironment in the development of immunotherapy approaches. Progress has also made in identifying the complex heterogeneity and diverse functions of cancer-associated fibroblasts in this desmoplastic cancer. Assays measuring circulating cell-free DNA and cell-free tumour DNA are emerging as clinical tools for detection and monitoring of the disease. Molecularly targeted therapy for CCA has now become a reality, with three drugs targeting oncogenic fibroblast growth factor receptor 2 (FGFR2) fusions and one targeting neomorphic, gain-of-function variants of isocitrate dehydrogenase 1 (IDH1) obtaining regulatory approval. By contrast, immunotherapy using immune-checkpoint inhibitors has produced disappointing results in patients with CCA, underscoring the requirement for novel immune-based treatment strategies. Finally, liver transplantation for early stage intrahepatic CCA under research protocols is emerging as a viable therapeutic option in selected patients. This Review highlights and provides in-depth information on these advances.

Abstract 814: Novel strategy for aptamer-directed nanovesicle targeting in cholangiocarcinoma

Background: Cholangiocarcinoma (CCA) is a heterogeneous malignancy arising from the biliary epithelium. Its diverse molecular landscape and aggressive biology render many anti-cancer therapies ineffective. Nanovesicle technology provides an opportunity for therapeutic inhibition of oncogenic targets that have been previously classified as undruggable. EpCAM is an epithelial-specific, transmembrane glycoprotein with increased expression in human and murine CCA which can be used for nanovesicle targeting. As a proof of concept study, we designed and validated a novel strategy to direct therapeutic milk-derived nanovesicles (tMNVs) to CCA tumors.

Methods: tMNVs were decorated with RNA nanoparticles containing a validated aptamer (EpDT3) against EpCAM conjugated to a cholesterol-triethylene-glycol (TEG) scaffold containing an Alexa647 fluorophore. Human and murine CCA cell lines were treated with aptamer directed tMNVs and assessed for nanovesicle uptake by fluorescent microscopy. CCA tumor tissue, derived from orthotopic implantation of a syngeneic CCA cell line, SB1, into a C57BL/6 mouse, was collected and treated with either aptamer-directed or bare tMNVs ex vivo, and compared with adjacent normal liver tissue. Flow cytometry was utilized to characterize tMNVs absorption profile. C57BL/6 mice who had previously undergone SB1 orthotopic and flank implantation were treated with aptamer-directed tMNVs by tail-vein injection and subsequently euthanized. Tissue was collected for biodistribution analyses by fluorescent microscopy. The experiment was repeated in NOD-scid mice following orthotopic implantation of patient derived xenograft (PDX) CCA tumor.

Results: Both human and murine CCA cells treated with aptamer-directed tMNVs demonstrated high fluorescent signal consistent with tMNV absorption within 12 hours of application. Flow cytometry analysis showed aptamer-directed tMNVs were absorbed at a higher proportion by CCA tumors than bare tMNVs ex vivo. Aptamer-directed tMNVs also had better absorption by CCA tumors compared to adjacent normal liver tissue. Following treatment with aptamer-directed or bare tMNVs in vivo, fluorescent microscopy demonstrated that aptamer-directed tMNVs were significantly better absorbed in the orthotopic SB1 tumors, followed by the subcutaneous tumors. Minimal fluorescent signal was noted in the normal adjacent liver. Orthotopically implanted PDX tumors also demonstrated high fluorescent signals following intravenous treatment with aptamer-directed tMNVs.

Conclusions: Utilizing a novel targeting strategy, we were able to design tMNVs capable of reliably and specifically targeting CCA in preclinical models. This work is foundational to the future application of nanovesicle technology in the CCA treatment paradigm.

Citation Format: Mincheng Yu, Jennifer L. Tomlinson, Emilien J. Loeuillard, Ryan D. Watkins, Caitlin B. Conboy, Shohei Takaichi, Nathan W. Werneburg, Roberto Alva-Ruiz, Amro Abdelrahman, Danielle M. Carlson, Jingchun Yang, Sumera I. Ilyas, Gregory J. Gores, Tushar Patel, Rory L. Smoot. Novel strategy for aptamer-directed nanovesicle targeting in cholangiocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 814.

Abstract IA21: Molecular Pathogenesis and Cells of Origin of Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) originates in the intrahepatic biliary tree above the second order bile ducts. There are two primary histological subtypes of iCCA: small bile duct iCCAs which arise at the level of the smaller intrahepatic bile ducts, and large bile duct iCCAs which arise in the large intrahepatic bile ducts. Hepatic stem or progenitor cells and cuboidal cholangiocytes are the cells of origin of small bile duct iCCA, whereas large bile duct iCCAs arise from columnar mucous cholangiocytes or peribiliary glands. The molecular pathogenesis of iCCA is distinct from the other anatomic subtypes of CCA. Potentially actionable genomic aberrations that occur in iCCA include fibroblast growth factor receptor 2 (FGFR2) gene fusions, isocitrate dehydrogenase (IDH) 1 and 2 mutations, BRAF mutations, and neutrotrophic tyrosine receptor kinase (NTRK) gene fusions. Epigenetic aberrations that occur in iCCA include inactivating mutations of chromatin remodeling genes such as BAP1 and ARIDIA. Additionally, IDH 1/2 mutations lead to the production of oncometabolites with consequent widespread epigenetic changes. IDH inhibitors and FGFR inhibitors have now received FDA approval for IDH mutated and FGFR altered CCA, respectively. Immune checkpoint inhibition has received tissue agnostic FDA approval for mismatch repair deficient/MSI high CCAs. Other targeted therapies such as PARP inhibitors and CDK4/6 inhibitors are under active investigation.

Citation Format: Sumera I Ilyas. Molecular Pathogenesis and Cells of Origin of Intrahepatic Cholangiocarcinoma [abstract]. In: Proceedings of the AACR Special Conference: Advances in the Pathogenesis and Molecular Therapies of Liver Cancer; 2022 May 5-8; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(17_Suppl):Abstract nr IA21.

Abstract 1315: Tumor necrosis factor related apoptosis inducing ligand fosters myeloid derived suppressor cell mediated tumor immune evasion in cholangiocarcinoma

Background and Aims: Tumor necrosis factor related apoptosis inducing ligand (TRAIL) is predominantly expressed on immune cells. Although TRAIL biology has garnered considerable attention as a potential anti-cancer strategy, TRAIL agonists have had very limited anti-cancer activity in humans. TRAIL signaling can attenuate the T lymphocyte response. However, this potential immunosuppressive function of TRAIL has not been examined in cancer biology. Cholangiocarcinoma (CCA), a highly lethal biliary tract cancer, has a dense immunosuppressive microenvironment. Accordingly, CCA provides a model to examine the potential immune regulatory function of TRAIL in cancer biology.

Methods: Using a syngeneic, orthotopic murine model of CCA (PMID: 29464042), murine CCA cells (SB cells) that express both Trail and Trail receptor (Tr) were implanted into livers of WT and Tr-/- mice. Hence, in this model the host immune cells express Trail but not the receptor; therefore, they would be capable of inducing TRAIL-mediated apoptosis in CCA cells but would be resistant to TRAIL-mediated immunosuppression. After 4 weeks of tumor growth, mice were sacrificed, and tumors were characterized using flow cytometry.

Results: We observed that Tr-/- mice had a significant reduction in tumor burden compared to WT mice. Moreover, tumor bearing Tr-/- mice had a significant increase in cytotoxic T lymphocytes (CTLs) and enhanced CTL effector function. Myeloid-derived suppressor cells (MDSCs) were significantly decreased in Tr-/- tumors compared to WT tumors. Furthermore, implantation of SB cells devoid of Trail (SB-Trail-/-) into WT mice resulted in a significant reduction in tumor burden and MDSC infiltration. In vitro functional studies employing SB cells deficient in Tr (SB-Tr-/-) and MDSCs were carried out. There was a significant reduction in proliferation and immunosuppressive function of MDSCs when cocultured with SB-Tr-/- compared to SB cells. These results indicate that TRAIL-TR fosters MDSC growth and immunosuppressive function.

In conclusion, we have demonstrated that Tr-/- mice have a significant reduction in CCA tumor burden and MDSC infiltration. Consequently, Tr-/- tumors have enhanced CTL infiltration and function. These data suggest that the TRAIL-TR system mediates tumors immune evasion via MDSCs, and direct targeting of TRAIL on CCA cells is a potential anti-tumor strategy.

Citation Format: Emilien Loeuillard, Jingchun Yang, Haidong Dong, Gregory J. Gores, Sumera I. Ilyas. Tumor necrosis factor related apoptosis inducing ligand fosters myeloid derived suppressor cell mediated tumor immune evasion in cholangiocarcinoma [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 1315.

Cholangiocarcinoma: what are the most valuable therapeutic targets - cancer-associated fibroblasts, immune cells, or beyond T cells?

INTRODUCTION

CCAs are dense and desmoplastic tumors with an abundant tumor microenviroment (TME). The evolving TME is characterized by reciprocal interactions between cancer cells and their environment and is essential in facilitating tumor progression. The TME has nonimmune and immune components. Nonimmune cell types include cancer-associated fibroblasts (CAFs) and endothelial cells accompanying tumor angiogenesis. Immune cell types include elements of the innate and adaptive immune response, and can have pro-tumor or antitumor roles. The TME can shape treatment response and resistance. Therefore, elements of the TME are attractive therapeutic targets. TME targeting therapies have been evaluated in preclinical and clinical studies but only a small subset of patients has a meaningful response.

AREAS COVERED

We discuss the TME components and potential TME targeting strategies. Literature search was performed on PubMed and ClinicalTrials.gov until October 2021.

EXPERT OPINION

Elucidating the CCA TME is essential for developing effective treatment strategies. Preclinical models that recapitulate the disease (such as organoids) are important tools in uncovering the intricate cross talk in the CCA TME. Characterization of patient-derived specimens using multi-omic and single-omic technologies can dissect the cellular interplay in the CCA TME, which can guide development of effective treatment strategies and identify biomarkers for patient stratification.

Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a highly lethal adenocarcinoma of the hepatobiliary system, which can be classified as intrahepatic, perihilar and distal. Each anatomic subtype has distinct genetic aberrations, clinical presentations and therapeutic approaches. In endemic regions, liver fluke infection is associated with CCA, owing to the oncogenic effect of the associated chronic biliary tract inflammation. In other regions, CCA can be associated with chronic biliary tract inflammation owing to choledocholithiasis, cholelithiasis, or primary sclerosing cholangitis, but most CCAs have no identifiable cause. Administration of the anthelmintic drug praziquantel decreases the risk of CCA from liver flukes, but reinfection is common and future vaccination strategies may be more effective. Some patients with CCA are eligible for potentially curative surgical options, such as resection or liver transplantation. Genetic studies have provided new insights into the pathogenesis of CCA, and two aberrations that drive the pathogenesis of non-fluke-associated intrahepatic CCA, fibroblast growth factor receptor 2 fusions and isocitrate dehydrogenase gain-of-function mutations, can be therapeutically targeted. CCA is a highly desmoplastic cancer and targeting the tumour immune microenvironment might be a promising therapeutic approach. CCA remains a highly lethal disease and further scientific and clinical insights are needed to improve patient outcomes.

The YAP-Interacting Phosphatase SHP2 Can Regulate Transcriptional Coactivity and Modulate Sensitivity to Chemotherapy in Cholangiocarcinoma

The Hippo pathway effector Yes-associated protein (YAP) is localized to the nucleus and transcriptionally active in a number of tumor types, including a majority of human cholangiocarcinomas. YAP activity has been linked to chemotherapy resistance and has been shown to rescue KRAS and BRAF inhibition in RAS/RAF-driven cancers; however, the underlying mechanisms of YAP-mediated chemoresistance have yet to be elucidated. Herein, we report that the tyrosine phosphatase SHP2 directly regulates the activity of YAP by dephosphorylating pYAPY357 even in the setting of RAS/RAF mutations, and that diminished SHP2 phosphatase activity is associated with chemoresistance in cholangiocarcinomas. A screen for YAP-interacting tyrosine phosphatases identified SHP2, and characterization of cholangiocarcinomas cell lines demonstrated an inverse relationship between SHP2 levels and pYAPY357. Human sequencing data demonstrated lower SHP2 levels in cholangiocarcinomas tumors as compared with normal liver. Cell lines with low SHP2 expression and higher levels of pYAPY357 were resistant to gemcitabine and cisplatin. In cholangiocarcinomas cells with high levels of SHP2, pharmacologic inhibition or genetic deletion of SHP2 increased YAPY357 phosphorylation and expression of YAP target genes, including the antiapoptotic regulator MCL1, imparting resistance to gemcitabine and cisplatin. In vivo evaluation of chemotherapy sensitivity demonstrated significant resistance in xenografts with genetic deletion of SHP2, which could be overcome by utilizing an MCL1 inhibitor. IMPLICATIONS: These findings demonstrate a role for SHP2 in regulating YAP activity and chemosensitivity, and suggest that decreased phosphatase activity may be a mechanism of chemoresistance in cholangiocarcinoma via a MCL1-mediated mechanism.

The rise of the FGFR inhibitor in advanced biliary cancer: the next cover of time magazine?

Cholangiocarcinomas (CCAs) are heterogeneous tumors arising from the biliary tract with features of cholangiocyte differentiation. CCAs are aggressive tumors with limited treatment options and poor overall survival. Only a subset of CCA patients with early stage disease can avail potentially curative treatment options. For advanced biliary tract tumors, currently there are limited effective treatment modalities. Recent advances have provided greater insight into the genomic landscape of CCAs. The fibroblast growth factor receptor (FGFR) pathway is involved in key cellular processes essential to survival and differentiation. Accordingly, aberrant FGFR signaling has significant oncogenic potential. Recent discovery of FGFR2 gene fusions in CCA has heightened interest in FGFR inhibition in advanced biliary tract cancer. These findings have served as a catalyst for ongoing clinical investigation of FGFR inhibition in CCA patients with various FGFR signaling abnormalities. Herein, we review FGFR aberrations in CCA and their prognostic implications, FGFR targeting as a viable therapeutic option in advanced biliary tract malignancies, and future directions for development of combination approaches utilizing FGFR inhibition.