Differentially Expressed Genes Between High-Metastatic LOVO-HM and Wild-Type LOVO Colorectal Cancer Cell Lines

Colorectal cancer (CRC) remains a leading cause of cancer-related morbidity and mortality globally, with 30-40% of cases developing metastasis, primarily to the liver (CRLM). While immunotherapy has shown promise for the treatment of CRC, CRLM patients still experience limited therapeutic benefits potentially due to an immunosuppressive tumor microenvironment (TME). Therefore, it is urgently needed to elucidate the key-players that drives CRLM and potentiates immunotherapeutic resistance. In this study, we started from establishing a liver-metastatic subline of LoVo cells through continuous passaging in vivo, allowing the screening of RNA expression profiles associated with CRLM. Combining spatial-transcriptomic sequencing and single-cell analysis, we demonstrated a significant upregulation of SPP1 (secreted phosphoprotein 1) expression and secretion in CRLM, and potentiated its contribution to immunotherapeutic resistance. By applying patient-derived xenograft/organoid models and various syngeneic culturing systems, we discovered that SPP1 manipulates the production of CXCL12 by cancer-associated fibroblasts (CAFs) through activating the β-catenin/HIF-1α-related transcription, thus drives a feedback loop for cancer development, shapes an immunosuppressive landscape and contributes to primary/acquired resistance against immunotherapy. Our study underscores the potential of targeting SPP1 and CAFs as a strategy to overcome immunotherapeutic resistance in CRC, especially for CRLM. By providing robust preclinical evidence, we advocate for further investigation into SPP1 as a biomarker and a druggable target for precision cancer treatment. This research contributes critical insights into the intricate interactions within the TME and offers promising avenues for enhancing therapeutic outcomes in CRC patients facing liver metastasis.