Novel and emerging targets for cholangiocarcinoma progression: therapeutic implications

Clinical outcomes of immune checkpoint inhibitor combined with other targeted or immunological therapy regimens for the treatment of advanced bile tract cancer: a systematic review and meta-analysis

Background and aims

A single immune checkpoint inhibitor (ICI) regimen has limited value in treating advanced bile tract cancer (BTC); therefore, ICI combination therapy is often applied. This meta-analysis aimed to evaluate the effectiveness and safety of ICI combination therapy for advanced BTC.

Methods

The study protocol was registered on PROSPERO (CRD42023452422). Data on the median progression-free survival (PFS), median overall survival (OS), objective response rate (ORR), disease control rate (DCR), and grade ≥3 adverse events (AEs) reported in relevant studies were pooled and analyzed to determine the efficacy and safety of ICI combination therapy.

Results

In total, 15 studies with 665 patients were included in this meta-analysis. The overall ORR and DCR were 34.6% and 77.6%, respectively. The overall median PFS and OS were 6.06 months [95% confidence interval (CI): 4.91-7.21] and 12.11 months (95% CI: 10.66-13.55), respectively. Patients receiving ICI combination therapy in addition to other therapies had a considerably prolonged median PFS and OS (z=9.69, p<0.001 and z=16.17, p<0.001). Patients treated as first-line treatment had a substantially longer median PFS and OS compared to patients treated as non-first-line treatment (z=11.19, p<0.001 and z=49.17, p<0.001). The overall pooled grade ≥3 AEs rate was 38.2% (95% CI: 0.268-0.497) and was not influenced by whether ICI therapy was combined with other treatments or not or the treatment line.

Conclusion

Advanced BTC patients may benefit from ICI combination treatment without additional AEs. However, concurrent chemotherapy or radiotherapy is still needed to achieve better outcomes.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023452422.

Cholangiocarcinoma: Pathologic and Molecular Classification in the Era of Precision Medicine

CONTEXT.—

Cholangiocarcinoma (CCA) is a heterogeneous cancer of the bile duct, and its diagnosis is often challenging.

OBJECTIVE.—

To provide insights into state-of-the-art approaches for the diagnosis of CCA.

DATA SOURCES.—

Literature review via PubMed search and authors' experiences.

CONCLUSIONS.—

CCA can be categorized as intrahepatic or extrahepatic. Intrahepatic CCA is further classified into small-duct-type and large-duct-type, whereas extrahepatic CCA is classified into distal and perihilar according to site of origin within the extrahepatic biliary tree. Tumor growth patterns include mass forming, periductal infiltrating, and intraductal tumors. The clinical diagnosis of CCA is challenging and usually occurs at an advanced tumor stage. Pathologic diagnosis is made difficult by tumor inaccessibility and challenges in distinguishing CCA from metastatic adenocarcinoma to the liver. Immunohistochemical stains can assist in differentiating CCA from other malignancies, such as hepatocellular carcinoma, but no distinctive CCA-specific immunohistochemical profile has been identified. Recent advances in next-generation sequencing-based high-throughput assays have identified distinct genomic profiles of CCA subtypes, including genomic alterations that are susceptible to targeted therapies or immune checkpoint inhibitors. Detailed histopathologic and molecular evaluations of CCA by pathologists are critical for correct diagnosis, subclassification, therapeutic decision-making, and prognostication. The first step toward achieving these goals is to acquire a detailed understanding of the histologic and genetic subtypes of this heterogeneous tumor group. Here, we review state-of-the-art approaches that should be applied to establish a diagnosis of CCA, including clinical presentation, histopathology, staging, and the practical use of genetic testing methodologies.

Moving beyond single-agent checkpoint inhibition in biliary tract cancers: what is the next frontier?

Background: Immunotherapy has been shown to improve outcomes for patients with cancer. Biliary tract cancers are a group of lethal diseases, and immunotherapy is an exciting new strategy to treat patients in advanced stages. Role of immunotherapy in biliary cancers: Durvalumab, an anti-PD-L1 antibody, is a new immunotherapy option for patients with advanced biliary cancers. In a randomized phase III trial, the combination of durvalumab and chemotherapy improved disease outcomes, including overall survival, in patients with advanced biliary cancers regardless of PD-L1 expression. Future perspective: Promising new combinations with new and potent antibodies or antiangiogenics are under development. Combinations with new immunotherapy agents targeting CTLA-4 or OX40 can enhance T-cell activation and improve outcomes compared with single anti-PD-1/PD-L1 agents. Furthermore, ctDNA is being used as an alternative to tissue genomic analysis and can be used to identify actionable targets. In this review, we will discuss the most important studies involving immunotherapy in biliary cancers as well as future perspectives in the field.

New molecular mechanisms in cholangiocarcinoma: signals triggering interleukin-6 production in tumor cells and KRAS co-opted epigenetic mediators driving metabolic reprogramming

Background

Cholangiocarcinoma (CCA) is still a deadly tumour. Histological and molecular aspects of thioacetamide (TAA)-induced intrahepatic CCA (iCCA) in rats mimic those of human iCCA. Carcinogenic changes and therapeutic vulnerabilities in CCA may be captured by molecular investigations in bile, where we performed bile proteomic and metabolomic analyses that help discovery yet unknown pathways relevant to human iCCA.

Methods

Cholangiocarcinogenesis was induced in rats (TAA) and mice (Jnk^Δhepa + CCl₄ + DEN model). We performed proteomic and metabolomic analyses in bile from control and CCA-bearing rats. Differential expression was validated in rat and human CCAs. Mechanisms were addressed in human CCA cells, including Huh28-KRAS^G12D cells. Cell signaling, growth, gene regulation and [U-¹³C]-D-glucose-serine fluxomics analyses were performed. In vivo studies were performed in the clinically-relevant iCCA mouse model.

Results

Pathways related to inflammation, oxidative stress and glucose metabolism were identified by proteomic analysis. Oxidative stress and high amounts of the oncogenesis-supporting amino acids serine and glycine were discovered by metabolomic studies. Most relevant hits were confirmed in rat and human CCAs (TCGA). Activation of interleukin-6 (IL6) and epidermal growth factor receptor (EGFR) pathways, and key genes in cancer-related glucose metabolic reprogramming, were validated in TAA-CCAs. In TAA-CCAs, G9a, an epigenetic pro-tumorigenic writer, was also increased. We show that EGFR signaling and mutant KRAS^G12D can both activate IL6 production in CCA cells. Furthermore, phosphoglycerate dehydrogenase (PHGDH), the rate-limiting enzyme in serine-glycine pathway, was upregulated in human iCCA correlating with G9a expression. In a G9a activity-dependent manner, KRAS^G12D promoted PHGDH expression, glucose flow towards serine synthesis, and increased CCA cell viability. KRAS^G12D CAA cells were more sensitive to PHGDH and G9a inhibition than controls. In mouse iCCA, G9a pharmacological targeting reduced PHGDH expression.

Conclusions

In CCA, we identified new pro-tumorigenic mechanisms: Activation of EGFR signaling or KRAS mutation drives IL6 expression in tumour cells; Glucose metabolism reprogramming in iCCA includes activation of the serine-glycine pathway; Mutant KRAS drives PHGDH expression in a G9a-dependent manner; PHGDH and G9a emerge as therapeutic targets in iCCA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02386-2.