Caveolin-1: oxidative stress target in tumor cells / 生理学报

Aberrant oxidative metabolism in cells is one of the hallmarks of cancer. Overproduction of reactive species promotes carcinogenesis by inducing genetic mutations and activating oncogenic pathways, and thus, antioxidant therapy is considered as an important strategy for cancer prevention and treatment. Caveolin-1 (Cav-1), a constituent protein of caveolae, is involved in not only the formation of the caveolae, vesicular transport, maintaining cholesterol homeostasis directly, but also many cellular physiological and pathological processes including growth, regulation of mitochondrial antioxidant level, apoptosis and carcinomas by interacting with a lot of signaling molecules through caveolin scaffolding domain. Cav-1 has also been shown to mediate tumor genesis and progression through oxidative stress modulation, while Cav-1-targeted treatment could scavenge the reactive species. Intracellular reactive species could modulate the expression, degradation, post-translational modifications and membrane trafficking of Cav-1. More importantly, emerging evidence has indicated that multiple antioxidants could exert antitumor activities in cancer cells by modulating the signaling of Cav-1. This paper reviewed the research progresses on the roles of Cav-1 and oxidative stress in tumorigenesis and development, and would provide new insights on designing strategies for cancer prevention or treatment.

Different subtypes of estrogen receptor α and related signal molecules in the hippocampus are associated with spatial cognitive impairment of diabetic mice / 生理学报

To study the correlation between the spatial cognitive impairment and different subtypes of estrogen receptor α (ERα) of hippocampus in diabetic mice, we used alloxan (intraperitoneal injection) to induce type 1 diabetes in male Kunming mice and compared the spatial cognitive ability of the model mice with that of control mice through Morris water maze test. Meanwhile, using Western blot, we detected the protein expressions of ER-α36, ER-α66, caveolin-1, PKCα, cAMP-response element binding protein 2 (CREB2), and synaptophysin (Syn) in the hippocampus of the mice. The results showed that on the 3rd and 5th days of training, the ability of spatial learning and memory in the diabetic mice was significantly inferior to that of the control mice (P < 0.05). In the diabetic mice, the protein expressions of caveolin-1 and PKCα were decreased (P < 0.05), but ER-α66 expression was unaffected, while ER-α36 and CREB2 expressions were significantly increased (P < 0.05) compared with those of the control mice. The results suggest that abnormal expression of ER-α36 and related signal molecules may be important factors for diabetes-induced spatial cognitive impairment.

Caveolin-1 is involved in DNA damage and repair signaling in X-irradiated Chang liver cells / 生理学报

Caveolin-1 (Cav-1), as an important structural protein of caveolae, has been proven to be correlated with several signal transduction pathways. Recent studies have shown that Cav-1 may play a critical role in response to DNA damage in irradiated pancreatic cancer cells. However, it is not known whether down-regulation of Cav-1 is required to enhance the damage of other kinds of human cells exposed to X-radiation. In this study, the role of Cav-1 in Chang liver cell line (CHL) exposed to X-radiation was investigated. Cav-1 knockdown cell line (CHL-CAV7) was stably established by the siRNA plasmids transfection, and Cav-1 expression was suppressed by 60%, compared with that of control group (CHL-C) which was transfected with non-targeting plasmids. Cellular survival ability and the expressions of proteins related to DNA damage and repair were examined by colony formation assay and Western blot, respectively. Down-regulation of Cav-1 expression induced a significant decrease of the survival rate in CHL-CAV7 cells exposed to 8 and 10 Gy X-radiation. Compared with CHL-C cells, CHL-CAV7 cells showed increased γH2AX expression, as well as decreased p-ATM, DNA-dependent protein kinase, catalytic subunit (DNA-PKcs) and p53 protein expressions when treated with X-radiation. Meanwhile, the colocalization of Mdm2 and Cav-1 was decreased in CHL-CAV7 cells compared with that in CHL-C cells. These results suggest that the down-regulation of Cav-1 may aggravate DNA damage of CHL cells through reducing the interaction of Cav-1 and Mdm2, which results in the promotion of p53 degradation.