Liver cancer, particularly hepatocellular carcinoma (HCC), remains one of the leading causes of cancer-related mortality worldwide. Despite advancements in therapeutic options, the variability in patient responses highlights a significant challenge in personalising treatment. Understanding this heterogeneity is crucial for improving outcomes. A promising avenue for precision medicine lies in the development of human-correlated genetic models, which offer deeper insights into the disease's complexity. These models, which replicate key features of human HCC, have allowed researchers to investigate the molecular and histopathological characteristics of liver cancer and test novel therapies more effectively.
Development of Human-Correlated HCC Models
To advance our understanding of HCC and its various subtypes, a team of researchers developed a comprehensive suite of genetically modified mouse models that replicate the most common genetic alterations seen in human liver cancer. These models, which use a viral vector system to introduce genetic changes into adult hepatocytes, closely mirror the clonal evolution observed in human cancer. The genetic alterations incorporated into the models were selected based on common mutations found in HCC patients, such as changes in the WNT signalling pathway, tumour suppressor genes and the RTK–RAS–PI3K growth pathways.
By inducing these genetic changes and allowing them to evolve over time, researchers were able to recreate HCC’s characteristic clonal expansion, histopathological appearance and metastasis. Notably, the researchers observed that combinations of mutations, rather than the total number of mutations, drove distinct tumour characteristics, including tumour growth rates, survival outcomes and the spread of the disease. This finding underscores the importance of understanding the genetic landscape of HCC at a molecular level, as different genetic profiles contribute to the variability in tumour behaviour and treatment response.
Cross-Species Transcriptomic Alignment
In order to evaluate how accurately these mouse models reflected human disease, the researchers performed a comprehensive transcriptomic analysis, comparing the gene expression profiles of their mouse models with data from human HCC patients. This comparison revealed four distinct molecular subtypes of HCC that were common across both species. These subtypes were defined by unique transcriptional characteristics related to various biological processes, such as metabolism, differentiation, immune response and tumour progression.
For example, one of the key subtypes identified in both human and mouse models was characterised by a high activation of the β-catenin signalling pathway, a mutation present in a significant proportion of human HCC patients. This subtype, associated with immune-excluded tumours, has been shown to be resistant to immune checkpoint inhibitors (ICIs), a class of therapies that have revolutionised the treatment of several cancers. The alignment of these subtypes between humans and mice allowed the researchers to map mouse models onto the human disease spectrum more precisely. By linking specific mutations with distinct molecular and histopathological features, these models offer valuable insight into the progression of the disease and its response to different therapeutic interventions.
Exploring New Therapeutic Strategies
One of the most exciting implications of these human-correlated models is their potential to identify novel therapeutic options for HCC. Researchers utilised high-throughput screening of FDA-approved cancer drugs on organoid cultures derived from mouse HCC models, aiming to discover compounds that could offer targeted treatment for specific HCC subtypes. Through this approach, cladribine, an antimetabolite previously unlinked to liver cancer, emerged as a promising candidate.
Cladribine was found to be particularly effective in treating tumours with activated β-catenin signalling, a common feature in a subtype of HCC that is typically resistant to standard treatments. Further experiments showed that cladribine, when combined with standard tyrosine kinase inhibitors (TKIs) like lenvatinib, significantly improved survival outcomes. This combination therapy not only reduced tumour size but also influenced the tumour microenvironment by increasing T-cell infiltration, a critical factor in enhancing the immune response to cancer. This discovery of cladribine’s efficacy in combination with lenvatinib holds promise for improving treatment options for patients with this difficult-to-treat subtype of HCC.
Moreover, the researchers explored a ‘priming’ strategy in which combination therapy with cladribine and lenvatinib was administered before immune checkpoint inhibition (ICI) therapy. This approach led to enhanced anti-tumour efficacy and increased T-cell infiltration into the tumour, suggesting that combination treatments can shift the tumour microenvironment to a more favourable immune phenotype. These findings highlight the potential of repurposing existing drugs for new therapeutic indications and the importance of studying the tumour microenvironment to optimise treatment responses.
The development of human-correlated genetic models for liver cancer has provided a valuable platform for advancing our understanding of the disease and its treatment. These models, which accurately replicate key molecular and histopathological features of human HCC, offer a more effective way to investigate the complexities of tumour progression and treatment response. By linking specific genetic alterations to distinct tumour characteristics and exploring targeted therapies, researchers have made significant strides towards personalised treatments for liver cancer. The identification of cladribine as a promising therapeutic candidate for specific subtypes of HCC illustrates the power of these models in uncovering new drug possibilities. Moreover, the integration of these findings with patient data enhances the likelihood of successful clinical translations, offering hope for more effective, precision-based treatments for liver cancer in the near future.
Source: Nature
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