217P - Tumor-derived CCL15 regulates RNA m6A methylation in cancer-associated fibroblasts to promote hepatocellular carcinoma growth

Background

HCC is a lethal malignancy characterized by rapid growth. The interaction between tumor cells and cancer-associated fibroblasts (CAFs) significantly influences HCC progression. CCL15 is predominantly expressed in HCC and strongly correlates with tumor size, indicating its critical role in HCC growth. However, previous studies suggest that CCL15 doesn’t directly stimulate cancer cell proliferation. The specific role and mechanism of CCL15 in HCC proliferation remain unknown.

Methods

Through single-cell RNA sequencing data and immunofluorescence, we identified that CCL15 was predominantly overexpressed by HCC cells. Furthermore, we discovered that CCL15 promotes HCC growth by stimulating the crosstalk between HCC cells and CAFs via CCR1 signaling, as evidenced by co-culture assays, organoid models, and allograft models.

Results

CCL15 induced the expression of FTO in CAFs through the STAT3 pathway. By m⁶A sequencing and RNA sequencing, we found that CEBPA mRNA, a transcription factor regulating CXCL5 expression, was a target of FTO. CXCL5, secreted by CAFs, activated the CXCR2 receptor on HCC cells and enhanced their proliferation. Notably, we found that interfering with CCL15 signaling using a neutralizing antibody attenuated HCC growth in heterotypic co-injection and patient-derived xenograft murine models. Finally, CXCL5 also upregulated CCL15 expression in HCC cells by modulating P53 expression through MDM2, forming a positive feedback loop.

Conclusions

Our study unveiled CCL15 as a key mediator in HCC progression, facilitating communication between HCC cells and CAFs. This highlighted a novel regulatory axis in HCC and suggested that targeting CCL15 could be a potential therapeutic strategy.

Legal entity responsible for the study

The author.

Funding

National Natural Science Foundation of China.

Disclosure

The author has declared no conflicts of interest.