Core Fucosylation Is Required for the Secretion of and the Enzymatic Activity of SOD3 in Nonsmall-Cell Lung Cancer Cells

Role of copper and SOD3-mediated extracellular redox regulation in tumor progression

Copper (Cu), an essential micronutrient, participates in several physiological processes, including cell proliferation and development. Notably, the disturbance of Cu homeostasis promotes tumor progression through the generation of oxidative stress. Chronic or excessive accumulation of reactive oxygen species (ROS) causes lipid peroxidation, protein denaturation, and enzyme inactivation, which leads to a breakdown of intracellular homeostasis and exacerbates tumor progression. The disruption of the ROS scavenging mechanism also reduces resistance to oxidative stress, leading to further deterioration in a disease state, and maintenance of redox homeostasis is thought to inhibit the onset and progression of various diseases. Superoxide dismutase 3 (SOD3), a Cu-containing secretory antioxidative enzyme, plays a key role in extracellular redox regulation, and the significant reduction in SOD3 facilitates tumor progression. Furthermore, the significant induction of SOD3 participates in tumor metastasis. This review focuses on the role of Cu homeostasis and antioxidative enzymes, including SOD3, in tumor progression, to help clarify the role of redox regulation.

Targeting branched N-glycans and fucosylation sensitizes ovarian tumors to immune checkpoint blockade

Aberrant glycosylation is a crucial strategy employed by cancer cells to evade cellular immunity. However, it's unclear whether homologous recombination (HR) status-dependent glycosylation can be therapeutically explored. Here, we show that the inhibition of branched N-glycans sensitizes HR-proficient, but not HR-deficient, epithelial ovarian cancers (EOCs) to immune checkpoint blockade (ICB). In contrast to fucosylation whose inhibition sensitizes EOCs to anti-PD-L1 immunotherapy regardless of HR-status, we observe an enrichment of branched N-glycans on HR-proficient compared to HR-deficient EOCs. Mechanistically, BRCA1/2 transcriptionally promotes the expression of MGAT5, the enzyme responsible for catalyzing branched N-glycans. The branched N-glycans on HR-proficient tumors augment their resistance to anti-PD-L1 by enhancing its binding with PD-1 on CD8+ T cells. In orthotopic, syngeneic EOC models in female mice, inhibiting branched N-glycans using 2-Deoxy-D-glucose sensitizes HR-proficient, but not HR-deficient EOCs, to anti-PD-L1. These findings indicate branched N-glycans as promising therapeutic targets whose inhibition sensitizes HR-proficient EOCs to ICB by overcoming immune evasion.

SOD3 regulates FLT1 to affect bone metabolism by promoting osteogenesis and inhibiting adipogenesis through PI3K/AKT and MAPK pathways

Osteoporosis is a chronic disease that seriously affects the quality of life and longevity of the elderly, so exploring the mechanism of osteoporosis is crucial for drug development and treatment. Bone marrow mesenchymal stem cells are stem cells with multiple differentiation potentials in bone marrow, and changing their differentiation direction can change bone mass. As an extracellular superoxide dismutase, Superoxide Dismutase 3 (SOD3) has been proved to play an important role in multiple organs, but the detailed mechanism of action in bone metabolism is still unclear. In this study, the results of clinical serum samples ELISA and single cell sequencing chip analysis proved that the expression of SOD3 was positively correlated with bone mass, and SOD3 was mainly expressed in osteoblasts and adipocytes and rarely expressed in osteoblasts in BMSCs. In vitro experiments showed that SOD3 can promote osteogenesis and inhibit adipogenesis. Compared with WT mice, the mice that were knocked out of SOD3 had a significant decrease in bone mineral density and significant changes in related parameters. The results of HE and IHC staining suggested that knocking out SOD3 would lead to fat accumulation in the bone marrow cavity and weakened osteogenesis. Both in vitro and in vivo experiments indicated that SOD3 affects bone metabolism by promoting osteogenesis and inhibiting adipogenesis. The results of transcriptome sequencing and revalidation showed that SOD3 can affect the expression of FLT1. Through in vitro experiments, we proved that FLT1 can also promote osteogenesis and inhibit adipogenesis. In addition, through the repeated experiments, the interaction between the two molecules (SOD3 and FLT1) was verified again. Finally, it was verified by WB that SOD3 regulates FLT1 to affect bone metabolism through PI3K/AKT and MAPK pathways.