Yan Gao

Was not provided for this article.

Adipogenesis, a crucial physiological process, serves to safely sequester lipids, thereby preventing lipotoxicity in peripheral organs and preserving metabolic health during obesity. While insulin signaling plays a pivotal role in adipogenesis, regulating factors, especially the braking mechanism governing this process, warrant further investigation. Our study identified proteasome-dependent degradation of the insulin receptor (IR) during the early stages of adipogenesis as a critical event for the mitotic clonal expansion phase of the adipocyte differentiation program. A series of studies confirmed that the ubiquitinated modification of IR is regulated by E3 ligase FBXO2, and this is based on IR phosphorylation. We further elucidated that the FBD domain of FBXO2 is indispensable for its function in catalyzing p-IR ubiquitination. Gain or loss of function of Fbxo2 inhibited or promoted SVF or 3T3L1 cells proliferation and adipogenesis both in vitro and in vivo, which regulated adipose hyperplasia and plasticity of adipose tissue. Moreover, FBXO2 played an important role in regulating the metabolic health of mice when subjected to caloric excess. Collectively, our findings unveil FBXO2 as a negative regulator of adipogenesis by impairing the insulin signaling pathway.

Adipogenesis, a crucial physiological process, serves to safely sequester lipids, thereby preventing lipotoxicity in peripheral organs and preserving metabolic health during obesity. While insulin signaling plays a pivotal role in adipogenesis, regulating factors especially the braking mechanism governing this process warrants further investigation. Our study identified proteasome-dependent degradation of the insulin receptor (IR) during the early stages of adipogenesis as a critical event for the mitotic clonal expansion phase of the adipocyte differentiation program. A series of studies confirmed that the ubiquitinated modification of IR is regulated by E3 ligase FBXO2 and this is based on its phosphorylation. We further elucidated that the FBD domain of FBXO2 is indispensable for its function in catalyzing p-IR ubiquitination. Gain or loss of function of Fbxo2 inhibited or promoted adipocyte progenitors proliferation and adipogenesis both in vitro and In vivo , which regulated adipose hyperplasia and plasticity of adipose tissue. Moreover, FBXO2 played an important role in regulating metabolic health of mice when subjected to caloric excess. Collectively, our findings unveil FBXO2 as a negative regulator of adipogenesis by impairing insulin signaling pathway.

Cancer-testicular antigens (CTAs) have been considered as potential prognostic biomarkers and therapeutic targets due to their specific expression and roles in tumorigenesis and metastasis. Among these, the function and mechanism of SPANXB1 in breast cancer brain metastasis (BCBM) remain poorly understood. In this study, we investigated the role of SPANXB1 in BCBM. Our results demonstrated that SPANXB1 was highly expressed in brain-tropic breast cancer cells and brain metastasis samples. Functional assays revealed that SPANXB1 promoted breast cancer cell invasion, migration, vasculogenic mimicry (VM) formation, and blood-brain barrier (BBB) extravasation, thereby accelerating the process of brain metastasis. Mechanistically, SPANXB1 facilitated chromatin opening at the MMP1 promoter region via histone H3R17me2 modification and upregulated transcription factor YY1, leading to increased MMP1 expression. In vivo experiments further confirmed the role of SPANXB1 in enhancing brain metastasis. Notably, metformin effectively inhibited the expression of SPANXB1 and MMP1, thereby attenuating BCBM progression. The present study indicates the potential of SPANXB1 as a diagnostic and therapeutic target for BCBM. Additionally, our findings suggest metformin as a promising therapeutic strategy for this highly aggressive disease.

The brain is a common metastatic site for carcinoma, and metabolic reprogramming is crucial for organ‐tropic metastatic formation. Li et al. found RARRES2 deficiency affected lipid metabolic reprogramming through PTEN‐mTOR‐SREBP1 pathway and promoted BCBrM. Other studies revealed that lipid metabolic reprogramming is part of metabolic adaptation to central nervous system. Overall, there is an intricate connection between lipid metabolism and brain metastases, and disrupting this connection may be a potential therapeutic target for BCBrM treatment.

Immune cell infiltration into the tumor microenvironment is associated with cancer prognosis. Tumor-associated macrophages play essential roles in tumor initiation, progression, and metastasis. Follistatin-like protein 1 (FSTL1), a widely expressed glycoprotein in human and mouse tissues, is a tumor suppressor in various cancers and a regulator of macrophage polarization. However, the mechanism by which FSTL1 affects crosstalk between breast cancer cells and macrophages remains unclear. By analyzing public data, we found that FSTL1 expression was significantly low in breast cancer tissues compared to normal breast tissues, and high expression of FSTL1 in patients indicated prolonged survival. Using flow cytometry, we found that total and M2-like macrophages dramatically increased in the metastatic lung tissues during breast cancer lung metastasis in Fstl1^+/− mice. Transwell assay in vitro and q-PCR experimental results showed that FSTL1 inhibited macrophage migration toward 4T1 cells by decreasing CSF1, VEGF-α, and TGF-β secretion in 4T1 cells. We demonstrated that FSTL1 inhibited M2-like tumor-associated macrophage recruitment toward the lungs by suppressing CSF1, VEGF-α, and TGF-β secretion in 4T1 cells. Therefore, we identified a potential therapeutic strategy for triple-negative breast cancer.