Immunotherapy in cholangiocarcinoma: From concept to clinical trials

Combined hepatocellular cholangiocarcinoma: A clinicopathological update

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a rare primary liver cancer associated with an appalling prognosis. The diagnosis and management of this entity have been challenging to physicians, radiologists, surgeons, pathologists, and oncologists alike. The diagnostic and prognostic value of biomarkers such as the immunohistochemical expression of nestin, a progenitor cell marker, have been explored recently. With a better understanding of biology and the clinical course of cHCC-CCA, newer treatment modalities like immune checkpoint inhibitors are being tried to improve the survival of patients with this rare disease. In this review, we give an account of the recent developments in the pathology, diagnostic approach, and management of cHCC-CCA.

Emerging Therapies in Management of Cholangiocarcinoma

Cholangiocarcinoma is a heterogeneous group of biliary tract cancers that has a poor prognosis and globally increasing incidence and mortality. While surgical resection remains the only curative option for the treatment of cholangiocarcinoma, the majority of cancers are unresectable at the time of diagnosis. Additionally, the prognosis of cholangiocarcinoma remains poor even with the current first-line systemic therapy regimens, highlighting the difficulty of treating locally advanced, metastatic, or unresectable cholangiocarcinoma. Through recent developments, targetable oncogenic driver mutations have been identified in the pathogenesis of cholangiocarcinoma, leading to the utilization of molecular targeted therapeutics. In this review, we comprehensively discuss the latest molecular therapeutics for the treatment of cholangiocarcinoma, including emerging immunotherapies, highlighting promising developments and strategies.

Lacking Immunotherapy Biomarkers for Biliary Tract Cancer: A Comprehensive Systematic Literature Review and Meta-Analysis

BACKGROUND

Immunotherapy has recently been incorporated into the spectrum of biliary tract cancer (BTC) treatment. The identification of predictive response biomarkers is essential in order to identify those patients who may benefit most from this novel treatment option. Here, we propose a systematic literature review and a meta-analysis of PD-1, PD-L1, and other immune-related biomarker expression levels in patients with BTC.

METHODS

Prisma guidelines were followed for this systematic review and meta-analysis. Eligible studies were searched on PubMed. Studies published between 2017 and 2022, reporting data on PD-1/PD-L1 expression and other immune-related biomarkers in patients with BTC, were considered eligible.

RESULTS

A total of 61 eligible studies were identified. Despite the great heterogeneity between 39 studies reporting data on PD-L1 expression, we found a mean PD-L1 expression percentage (by choosing the lowest cut-off per study) of 25.6% (95% CI 21.0 to 30.3) in BTCs. The mean expression percentages of PD-L1 were 27.3%, 21.3%, and 27.4% in intrahepatic cholangiocarcinomas (iCCAs-15 studies), perihilar-distal CCAs (p/dCCAs-7 studies), and gallbladder cancer (GBC-5 studies), respectively. Furthermore, 4.6% (95% CI 2.38 to 6.97) and 2.5% (95% CI 1.75 to 3.34) of BTCs could be classified as TMB-H and MSI/MMRd tumors, respectively.

CONCLUSION

From our analysis, PD-L1 expression was found to occur approximately in 26% of BTC patients, with minimal differences based on anatomical location. TMB-H and MSI molecular phenotypes occurred less frequently. We still lack a reliable biomarker, especially in patients with mismatch-proficient tumors, and we must need to make an effort to conceive new prospective biomarker discovery studies.

Immunotherapy in Biliary Tract Cancers: Where Are We?

PURPOSE OF REVIEW

Biliary tract cancers (BTCs) are a heterogenous group of cancers arising from the biliary tract. The hallmark of these cancers is the advanced stage of presentation and a paucity of durable treatment options. Despite the advances in targeted therapy and immunotherapy in solid tumors, systemic cytotoxic chemotherapy has remained the mainstay for cholangiocarcinomas.

RECENT FINDINGS

With advances in the understanding of the tumor microenvironment, genetic features, and inflammatory milieu, have led to the identification of tumor-infiltrating immune cells as indicators of prognosis and response to treatment in BTC. Through an improved comprehension of immunology, immuno-oncology is becoming another pillar of treatment along with traditional radiation, surgery, cytotoxic chemotherapy, and targeted therapies. This article reviews the evidence for immunotherapy use in cholangiocarcinoma, which still being in infancy, and offers promising new novel options for the management of biliary tract cancers.

Integrating cell interaction with transcription factors to obtain a robust gene panel for prognostic prediction and therapies in cholangiocarcinoma

Objective: The efficacy of immunotherapy for cholangiocarcinoma (CCA) is blocked by a high degree of tumor heterogeneity. Cell communication contributes to heterogeneity in the tumor microenvironment. This study aimed to explore critical cell signaling and biomarkers induced via cell communication during immune exhaustion in CCA.

Methods: We constructed empirical Bayes and Markov random field models eLBP to determine transcription factors, interacting genes, and associated signaling pathways involved in cell-cell communication using single-cell RNAseq data. We then analyzed the mechanism of immune exhaustion during CCA progression.

Results: We found that VEGFA-positive macrophages with high levels of LGALS9 could interact with HAVCR2 to promote the exhaustion of CD8+ T cells in CCA. Transcription factors SPI1 and IRF1 can upregulate the expression of LGALS9 in VEGFA-positive macrophages. Subsequently, we obtained a panel containing 54 genes through the model, which identified subtype S2 with high expression of immune checkpoint genes that are suitable for immunotherapy. Moreover, we found that patients with subtype S2 with a higher mutation ratio of MUC16 had immune-exhausted genes, such as HAVCR2 and TIGIT. Finally, we constructed a nine-gene eLBP-LASSO-COX risk model, which was designated the tumor microenvironment risk score (TMRS).

Conclusion: Cell communication-related genes can be used as important markers for predicting patient prognosis and immunotherapy responses. The TMRS panel is a reliable tool for prognostic prediction and chemotherapeutic decision-making in CCA.

Combined MEK/PD-L1 Inhibition Alters Peripheral Cytokines and Lymphocyte Populations Correlating with Improved Clinical Outcomes in Advanced Biliary Tract Cancer

PURPOSE

Biliary tract cancers (BTC) are aggressive malignancies refractory to chemotherapy and immunotherapy. MEK inhibition (MEKi)-based regimens may have utility in this disease when combined with PD-L1 blockade. We hypothesize that dual MEK/PD-L1 inhibition alters circulating soluble and cellular immune mediators to improve clinical outcomes in patients with advanced BTC.

EXPERIMENTAL DESIGN

We examined immune features in peripheral blood from 77 patients with advanced BTC enrolled in a phase II clinical trial investigating atezolizumab with or without cobimetinib. Plasma and peripheral blood mononuclear cells (PBMC) were isolated from whole blood to evaluate soluble factors and immune cell populations. Baseline blood samples were additionally compared with healthy donors to identify immune signatures unique to BTC.

RESULTS

At baseline, the soluble factors platelet-derived growth factor B (PDGF)-BB, placental growth factor (PlGF)-1, IL5, and IL17A were elevated in patients with BTC compared with healthy adult donors, and higher baseline frequencies of CD8+BTLA+ T cells correlated with better overall survival (OS) in this trial. There were also significant treatment-related alterations in several factors, including decreased PDGF-BB following combination treatment, that correlated with improved OS and progression-free survival (PFS). Higher baseline levels of IL23 and RANTES corresponded to improved clinical outcomes following combination treatment. Dual MEK/PD-L1 inhibition increased populations of CD4+TIM3+ and decreased CD8+VISTA+ T cells, correlating with worse OS and better PFS, respectively.

CONCLUSIONS

This work represents a comprehensive analysis of peripheral immune features in patients with BTC and systemic responses to dual MEK/PD-L1 inhibition. These data support further investigation to understand how MEKi combines with immunotherapeutic approaches to improve clinical outcomes for patients with advanced BTC.

Genistein Sensitizes Human Cholangiocarcinoma Cell Lines to Be Susceptible to Natural Killer Cells

Cholangiocarcinoma (CCA) is a lethal bile duct cancer, which has poor treatment outcomes due to its high resistance to chemotherapy and cancer recurrence. Activation of aberrant anti-apoptotic signaling pathway has been reported to be a mechanism of chemoresistance and immune escape of CCA. Therefore, reversal of anti-apoptotic signaling pathway represents a feasible approach to potentiate effective treatments, especially for CCA with high chemoresistance. In this study, we demonstrated the effects of genistein on reactivation of apoptosis cascade and increase the susceptibility of CCA cells to natural killer (NK-92) cells. Genistein at 50 and 100 µM significantly activated extrinsic apoptotic pathway in CCA cells (KKU055, KKU100, and KKU213A), which was evident by reduction of procaspase-8 and -3 expression. Pretreatment of CCA cells with genistein at 50 µM, but not NK-92 cells, significantly increased NK-92 cell killing ability over the untreated control, suggesting the ability of genistein to sensitize CCA cells. Interestingly, genistein treatment could greatly lower the expression of cFLIP, an anti-apoptotic protein involved in the immune escape pathway, in addition to upregulation of death receptors, Fas- and TRAIL-receptors, in CCA cells, which might be the underlying molecular mechanism of genistein to sensitize CCA to be susceptible to NK-92 cells. Taken together, this finding revealed the benefit of genistein as a sensitizer to enhance the efficiency of NK cell immunotherapy for CCA.

Precision Medicine in Biliary Tract Cancer

Precision medicine has become a dominant theme in the treatment of biliary tract cancers (BTCs). Although prognosis remains poor, technologies for improved molecular characterization along with the US Food and Drug Administration approval of several targeted therapies have changed the therapeutic landscape of advanced BTC. The hallmark of BTC oncogenesis is chronic inflammation of the liver and biliary tract regardless of the anatomical subtype. Subtypes of BTC correspond to distinct molecular characteristics, making BTC a molecularly heterogenous collection of tumors. Collectively, up to 40% of BTCs harbor a potentially targetable molecular abnormality, and the National Comprehensive Cancer Network guidelines recommend molecular profiling for all patients with advanced BTC. Use of circulating tumor DNA, immunohistochemistry, and next-generation sequencing continues to expand the utility for biomarker-driven management and molecular monitoring of BTC. Improving outcomes using biomarker-agnostic treatment for nontargetable tumors also remains a priority, and combinational treatment strategies such as immune checkpoint inhibition plus chemotherapy hold promise for this subgroup of patients.

An Insight into the Novel Immunotherapy and Targeted Therapeutic Strategies for Hepatocellular Carcinoma and Cholangiocarcinoma

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) constitute highly malignant forms of primary liver cancers. Hepatocellular and bile duct carcinogenesis is a multiplex process, caused by various genetic and epigenetic alterations, the influence of environmental factors, as well as the implication of the gut microbiome, which was undervalued in the previous years. The molecular and immunological analysis of the above malignancies, as well as the identification of the crucial role of intestinal microbiota for hepatic and biliary pathogenesis, opened the horizon for novel therapeutic strategies, such as immunotherapy, and enhanced the overall survival of cancer patients. Some of the immunotherapy strategies that are either clinically applied or under pre-clinical studies include monoclonal antibodies, immune checkpoint blockade, cancer vaccines, as well as the utilization of oncolytic viral vectors and Chimeric antigen, receptor-engineered T (CAR-T) cell therapy. In this current review, we will shed light on the recent therapeutic modalities for the above primary liver cancers, as well as on the methods for the enhancement and optimization of anti-tumor immunity.

MICA/B-targeted antibody promotes NK cell-driven tumor immunity in patients with intrahepatic cholangiocarcinoma

The major histocompatibility complex-class I chain related proteins A and B (MICA/B) is upregulated because of cellular stress and MICA/B shedding by cancer cells causes escape from NKG2D recognition favoring the emergence of cancers. Cholangiocarcinoma (CCA) is a relatively rare, though increasingly prevalent, primary liver cancer characterized by a late clinical presentation and a dismal prognosis. We explored the NKG2D-MICA/B axis in NK cells from 41 patients with intrahepatic cholangiocarcinoma (iCCA). The MICA/B-specific 7C6 mAb was used for ex vivo antibody-dependent cytotoxicity (ADCC) experiments using circulating, non tumor liver- and tumor-infiltrating NK cells against the HuCCT-1 cell line and patient-derived primary iCCA cells as targets. MICA/B were more expressed in iCCA than in non-tumoral tissue, MICA transcription being higher in moderately-differentiated compared with poorly-differentiated cancer. Serum MICA was elevated in iCCA patients in line with higher expression of ADAM10 and ADAM17 that are responsible for proteolytic release of MICA/B from tumor. Addition of 7C6 significantly boosted peripheral, liver- and tumor-infiltrating-NK cell degranulation and IFNγ production toward MICA/B-expressing established cell lines and autologous iCCA patient target cells. Our data show that anti-MICA/B drives NK cell anti-tumor activity, and provide preclinical evidence in support of 7C6 as a potential immunotherapeutic tool for iCCA.