Study proposes a novel therapeutic avenue for tackling EHF-induced cholangiocarcinogenesis

This study is led by Dr. Yiming Luo (Hepatic Surgery Centre, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology) and Professor. Huifang Liang (Hepatic Surgery Centre, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology). In their study, the researchers discovered that EHF directly binds to the promoter regions of GLI1 and CCL2, thereby stimulating their transcription. This finding was supported by dual-luciferase reporter gene assays and ChIP experiments.

Furthermore, they observed that blocking GLI1 effectively mitigated the upregulation of EHF in tumor cells and immunosuppressed animal models, resulting in decreased proliferation and growth of cholangiocarcinoma cells.

However, we found that the inhibitory effect of blocking GLI1 was then lost in C57 mice, an immunologically sound animal model."

Dr. Yiming Luo, Department of Liver Surgery, Tongji Hospital, Huazhong University of Science and Technology

Thus, more complex mechanisms may exist in the microenvironment of EHF-mediated tumors.

EHF, acting as a potent oncogenic transcription factor, likely employs multiple mechanisms beyond a single pathway. The researchers postulated that other crucial target genes might participate in tumor cell interactions. Through analyzing tissue sequencing results in an immunocompetent mouse model, they highlighted the cytokine pathway's significance and identified CCL2 as a pivotal effector gene. Validation experiments confirmed EHF's role in facilitating the migration and infiltration of TAMs into tumors via the CCL2-CCR2 axis, thereby complementing GLI1's function in tumor cells and offering a more comprehensive understanding of EHF-mediated cholangiocarcinogenesis. Additionally, they speculated on EHF's indirect influence on immune cells such as T cells, primarily mediated through macrophages, as evidenced by flow cytometry analysis.

Targeted therapy holds immense promise for CCA treatment by specifically addressing gene abnormalities, thereby enhancing patient survival and treatment outcomes. Leveraging EHF's critical role in cholangiocarcinoma, the researchers devised a strategy to inhibit EHF-induced CCA by targeting GLI1 and CCL2. GANT58, a GLI1-specific small-molecule inhibitor, exhibited significant efficacy in vitro, albeit with limited in vivo and clinical validation. Meanwhile, INCB3344, a specific CCL2-CCR2 antagonist, effectively reduced macrophage infiltration in target tissues. Combining these two inhibitors in animal experiments yielded promising results, significantly inhibiting EHF-mediated CCA development compared to control or single-drug treatments. These findings propose a novel therapeutic avenue for tackling EHF-induced cholangiocarcinogenesis.