The integration of single-cell and metabolomics reveals the increase of oxidative phosphorylation during the liver metastasis of colorectal cancer.

Abstract

Background: Colorectal cancer (CRC) is among the most prevalent malignant tumors, with liver metastasis as the leading cause of mortality. Although metabolic reprogramming is known to play a crucial role in tumor metastasis, our understanding of this process during colorectal cancer liver metastasis (CRLM) remains limited.

Methods: A stepwise mouse model of CRC liver metastasis was developed, and metabolomic profiling was performed to verify model stability and identify metabolic changes. Single-cell RNA sequencing (scRNA-seq) was used to assess oxidative phosphorylation (OXPHOS) activity within the metastatic tumor microenvironment (TME). Additionally, spatial transcriptomics (ST) was conducted to elucidate the spatial distribution of metabolic phenotypes within metastatic sites. Finally, in vivo experiments were conducted by administering TGFβ inhibitor (LY2157299) or OXPHOS inhibitor (IACS-010759) to evaluate the potential for liver metastasis, and in vitro, the functions of HCT116 and SW620 cells were assessed through Transwell assays and oxygen consumption rate (OCR) measurements.

Results: Metabolomic profiling revealed heightened tricarboxylic acid (TCA) cycle activity in liver metastases. ScRNA-seq analysis showed increased OXPHOS in metastatic cells, including a highly malignant cell subtype characterized by augmented OXPHOS. Further analysis identified a significant upregulation of OXPHOS associated with TGFβ pathway activation. ST localized this OXPHOS -enriched subtype within metastatic tissue. Both in vivo and in vitro experiments demonstrate that inhibition of TGFβ signaling reduces OXPHOS activity, thereby attenuating the progression of colorectal cancer liver metastasis.

Conclusions: This study identifies OXPHOS upregulation as a key metabolic alteration during CRC liver metastasis, which could be induced by TGFβ signaling pathway. These findings contribute to a refined understanding of CRC metabolic adaptation in liver metastases and may inform therapeutic strategies targeting OXPHOS in advanced CRC.