Abstract
Abstract Objectives To elucidate the role and molecular mechanism of elemene (ELE) in the malignant progression of colorectal cancer. Methods Bulk RNA-seq analysis was used to identify the genes regulated by elemene (ELE). Integrated single-cell transcriptome analysis was performed to dissect the cellular heterogeneity, malignant evolutionary trajectory, and cellular communication characteristics in the tumor microenvironment of colorectal cancer. Tumor progression was evaluated in vivo by transplantation in nude mice. In vitro, the protein expression levels of RGC32, SIRT7, p-STAT3, nuclear YAP, nuclear BRD4, KLF4 and SOX4 in HCT116 cells were detected by Western blot assay, and the cell proliferation was examined by flow cytometry and plate colony formation assay. Cell migration was detected by scratch assay. Cell invasion ability was detected by transwell assay. In addition, cell apoptosis was detected by flow cytometry. Results Elemene exerts antitumor effects by targeting and inhibiting the oncogene RGC32. As a signaling hub, RGC32 activates the transcriptional activity of P65/P50, a key subunit of the NF-κB pathway, which in turn drives the expression of the deacetylase SIRT7. SIRT7 has a dual regulatory function: on one hand, it inhibits the phosphorylation and degradation of YAP proteins by MST1 kinase to promote the stability of YAP proteins and nuclear translocation; on the other hand, SIRT7 activates the phosphorylation of STAT3 signaling, which induces the expression of the early growth response factor EGR1 (early growth response factor 1), and ultimately enhances the activity of the transcriptional coactivator BRD4. Single-cell transcriptome analysis confirmed that colorectal cancer tissues exhibit remarkable cellular heterogeneity. Cancer cells display highly proliferative and dedifferentiated stem-like properties, and RGC32 knockdown significantly downregulates SIRT7 expression and reshapes the cellular communication network in the tumor microenvironment. Notably, YAP and BRD4 synergistically activated the downstream oncogene network, which significantly promoted the stemness maintenance, proliferation, migration, invasion and anti-apoptosis of colorectal cancer cells. Conclusions By inhibiting RGC32, elemene blocked the downstream SIRT7/STAT3/BRD4 and SIRT7/YAP and synchronously inhibited the synergistic oncogenic effects of YAP and BRD4, which provided a new strategy for targeting colorectal cancer.