An Oncogenic Hepatocyte-Induced Orthotopic Mouse Model of Hepatocellular Cancer Arising in the Setting of Hepatic Inflammation and Fibrosis

From biology to the clinic - exploring liver metastasis in prostate cancer

Liver metastases from prostate cancer are associated with an aggressive disease course and poor prognosis. Results from autopsy studies indicate a liver metastasis prevalence of up to 25% in patients with advanced prostate cancer. Population data estimate that ~3-10% of patients with metastatic castration-resistant prostate cancer harbour liver metastases at the baseline, rising to 20-30% in post-treatment cohorts, suggesting that selective pressure imposed by novel therapies might promote metastatic spread to the liver. Liver metastases are associated with more aggressive tumour biology than lung metastases. Molecular profiling of liver lesions showed an enrichment of low androgen receptor, neuroendocrine phenotypes and high genomic instability. Despite advancements in molecular imaging modalities such as prostate-specific membrane antigen PET-CT, and liquid biopsy markers such as circulating tumour DNA, early detection of liver metastases from prostate cancer remains challenging, as both approaches are hampered by false positive and false negative results, impeding the accurate identification of early liver lesions. Current therapeutic strategies showed limited efficacy in this patient population. Emerging targeted radionuclide therapies, metastasis-directed therapy, and novel systemic agents have shown preliminary activity against liver metastases, but require further validation. Treatment with various novel prostate cancer therapies might lead to an increase in the prevalence of liver metastasis, underscoring the urgent need for coordinated efforts across preclinical and clinical researchers to improve characterization, monitoring, and management of liver metastases from prostate cancer. Elucidating molecular drivers of liver tropism and interactions with the liver microenvironment might ultimately help to identify actionable targets to enhance survival in this high-risk patient group.

Experimental Models of Hepatocellular Carcinoma-A Preclinical Perspective

Hepatocellular carcinoma (HCC), the most frequent form of primary liver carcinoma, is a heterogenous and complex tumor type with increased incidence, poor prognosis, and high mortality. The actual therapeutic arsenal is narrow and poorly effective, rendering this disease a global health concern. Although considerable progress has been made in terms of understanding the pathogenesis, molecular mechanisms, genetics, and therapeutical approaches, several facets of human HCC remain undiscovered. A valuable and prompt approach to acquire further knowledge about the unrevealed aspects of HCC and novel therapeutic candidates is represented by the application of experimental models. Experimental models (in vivo and in vitro 2D and 3D models) are considered reliable tools to gather data for clinical usability. This review offers an overview of the currently available preclinical models frequently applied for the study of hepatocellular carcinoma in terms of initiation, development, and progression, as well as for the discovery of efficient treatments, highlighting the advantages and the limitations of each model. Furthermore, we also focus on the role played by computational studies (in silico models and artificial intelligence-based prediction models) as promising novel tools in liver cancer research.

A novel mouse model for liver metastasis of prostate cancer reveals dynamic tumour-immune cell communication

Objectives

In contrast to extensive studies on bone metastasis in advanced prostate cancer (PCa), liver metastasis has been under‐researched so far. In order to decipher molecular and cellular mechanisms underpinning liver metastasis of advanced PCa, we develop a rapid and immune sufficient mouse model for liver metastasis of PCa via orthotopic injection of organoids from PbCre⁺; rb1^f/f;p53^f/f mice.

Materials and Methods

PbCre⁺;rb1^f/f;p53^f/f and PbCre⁺;pten^f/f;p53^f/f mice were used to generate PCa organoid cultures in vitro. Immune sufficient liver metastasis models were established via orthotopic transplantation of organoids into the prostate of C57BL/6 mice. Immunofluorescent and immunohistochemical staining were performed to characterize the lineage profile in primary tumour and organoid‐derived tumour (ODT). The growth of niche‐labelling reporter infected ODT can be visualized by bioluminescent imaging system. Immune cells that communicated with tumour cells in the liver metastatic niche were determined by flow cytometry.

Results

A PCa liver metastasis model with full penetrance is established in immune‐intact mouse. This model reconstitutes the histological and lineage features of original tumours and reveals dynamic tumour‐immune cell communication in liver metastatic foci. Our results suggest that a lack of CD8⁺ T cell and an enrichment of CD163⁺ M2‐like macrophage as well as PD1⁺CD4⁺ T cell contribute to an immuno‐suppressive microenvironment of PCa liver metastasis.

Conclusions

Our model can be served as a reliable tool for analysis of the molecular pathogenesis and tumour‐immune cell crosstalk in liver metastasis of PCa, and might be used as a valuable in vivo model for therapy development.

Synergizing sunitinib and radiofrequency ablation to treat hepatocellular cancer by triggering the antitumor immune response

Background

Minimally invasive radiofrequency ablation (RFA) is used as a first-line treatment option for hepatocellular cancer (HCC) with the weaknesses of incomplete ablation, tumor recurrence, and inferior outcomes. To overcome this limitation, we proposed to develop sunitinib-RFA integrated therapy with a potential of activating anti-HCC immune response.

Methods

Using our unique murine model, we developed a novel RFA platform with a modified human cardiac RF generator. Therapeutic efficacy of sunitinib–RFA combined treatment in HCC was tested in this platform. Tumor progression was monitored by MRI; tumor necrosis and apoptosis were detected by H&E and terminal deoxynucleotidyl transferase dUTP nick end labeling; immune reaction was defined by flow cytometry; and signaling molecules were examined with real-time PCR (qPCR), western blot, and immunohistochemical staining.

Results

A significantly reduced tumor growth and extended lift span were observed in the mice receiving combined treatment with RFA and sunitinib. This combined treatment significantly increased the frequency of CD8⁺ T cell, memory CD8⁺ T cell, and dendritic cells (DCs); decreased the frequency of regulatory T cells; and activated tumor-specific antigen (TSA) immune response in tumor microenvironment. We found that RFA caused PD-1 upregulation in tumor-infiltrated T cells by boosting hepatocyte growth factor (HGF) expression, which was suppressed by sunitinib treatment. We have also demonstrated that sunitinib suppressed VEGF’s effect in enhancing PD-L1 expression in DCs and attenuated heat-sink effect. The results indicate that RFA induced tumor destruction and release of in situ TSAs which can activate a tumoricidal immune response in sunitinib-treated mice, significantly improving anti-HCC therapeutic efficacy.

Conclusions

Sunitinib enables RFA-released in situ TSA to ignite an effective anti-tumor immune response by suppressing HGF and VEGF signaling pathways. Sunitinib–RFA as a synergistic therapeutic approach significantly suppresses HCC growth.