ABSTRACT
Cluster of differentiation 36 (CD36) is a membrane glycoprotein receptor capable of binding and transporting fatty acid. Nogo-B regulates the metabolism of fatty acids in the liver and affects the development of liver cancer. To date, it remains unclear whether the interaction between CD36 and Nogo-B affects the proliferation and migration of breast cancer cells. In the current study, we aimed to determine whether the interference of CD36 and Nogo-B affects the proliferation and migration of triple-negative breast cancer (TNBC) cells. The results showed that inhibition of CD36 or Nogo-B alone can inhibit the proliferation and migration of TNBC cells, and the inhibitory effect was more pronounced when CD36 and Nogo-B were inhibited simultaneously. Meanwhile, it was found that inhibition of CD36 and Nogo-B expression can inhibit the expression of Vimentin, B-cell lympoma-2 (BCL2) and proliferating cell nuclear antigen (PCNA). In vivo, knockdown of CD36 or Nogo-B in E0771 cells reduced its tumorigenic ability, which was further enhanced by knockdown of CD36 and Nogo-B simultaneously. Mechanistically, inhibition of CD36 and Nogo-B expression can decrease fatty acid binding protein 4 (FABP4) and fatty acid transport protein 4 (FATP4) expression. Moreover, overexpression of CD36 and Nogo-B-induced cell proliferation was attenuated by FABP4 siRNA, indicating that inhibition of CD36 and Nogo-B expression could inhibit the absorption and transport of fatty acids, thereby inhibiting the proliferation and migration of TNBC. Furthermore, inhibition of CD36 and Nogo-B expression activated the P53-P21-Rb signaling pathway which contributed to the CD36 and Nogo-B-inhibited proliferation and migration of TNBC. Taken together, the results suggest that inhibition of CD36 and Nogo-B can reduce the proliferation and migration of TNBC, which provides new targets for the development of drugs against TNBC.
Subject(s)
Humans , Triple Negative Breast Neoplasms/metabolism , Cell Movement , Cell Proliferation , Cell Line, Tumor , Fatty AcidsABSTRACT
Nogo protein is the fourth member of reticulin famity. Nogo mRNA produced by encoding gene transcription, forms three different RNA transcripts due to different promoter and splicing modes, namely Nogo-A, Nogo-B and Nogo-C protein. Nogo protein was first found in the central nervous system, and then proved to be widely expressed in peripheral tissues such as heart, liver and vascular endothelium. Studies have shown that Nogo protein can participate in the regulation of myocardial fibrosis through RhoA/Rho-associated kinase(ROCK) pathway, endoplasmic reticulum stress, Sce61 a and other signaling pathways. In this paper, the relationship between Nogo-A, Nogo-B, Nogo-C and myocardial fibrosis is briefly introduced.
ABSTRACT
Objective:To investigate the role of Nogo-B in mitochondrial reactive oxygen species(m-ROS)production and vascular remodeling in vascular smooth muscle cells(VSMCs), and to further clarify the molecular mechanism for Nogo-B in m-ROS production via regulating ATP synthase expression.Methods:A mouse model of vascular remodeling was established.The expression of Nogo-B in mouse smooth muscle cells was detected.Forty mice were divided into the AAV-NC+ control, AAV-NC+ angiotensin Ⅱ(AngⅡ), AAV-Nogo-B+ control and AAV-Nogo-B+ AngⅡ groups(n=10 for each group). VSMCs cultured in vitro were divided into the control group and the Nogo-B overexpression group(Ad-Nogo-B). The expression of Nogo-B in VSMCs in vitro stimulated with AngⅡ was detected.Through experiments conducted in vivo, Nogo-B was overexpressed in VSMCs, then VSMCs were stimulated with AngⅡ, and m-ROS production, tissue fibrosis and mitochondrial function were examined.The regulatory effects of Nogo-B on m-ROS production were explored.Molecular mechanisms for NoGO-B in vascular remodeling via regulating ATP synthase/m-ROS production were examined. Results:Compared with the control group, the expression of Nogo-B was decreased in VSMCs treated with AngⅡ(0.36±0.13 vs.1.00±0.13, t=8.44, P<0.05). The production of m-ROS, fibrosis and mitochondrial dysfunction were increased in VSMCs during vascular remodeling( P<0.05), while overexpression of Nogo-B significantly reduced m-ROS production, fibrosis and mitochondrial dysfunction( P<0.05). ATP synthase expression in VSMCs was positively regulated by Nogo-B.ATP synthase expression was higher in the AAV-Nogo-B+ AngⅡ group than in the AAV-NC+ AngⅡ group(0.86±0.14 vs.0.49±0.17, t=-3.97, P<0.05). The production of m-ROS was reduced by Nogo-B and was lower in the AAV-Nogo-B+ AngⅡ group than in the AAV-NC+ AngⅡ group(1.28±0.34 vs.3.26±0.57, t=7.18, P<0.05). Meanwhile, the ability of Nogo-B to mitigate the deleterious effects of oxidative stress in VSMCs could be offset by oligomycin. Conclusions:Nogo-B participates in vascular remodeling by regulating ATP synthase-mediated m-ROS production.
ABSTRACT
Nogo-B is a major family member of the reticulon protein family 4. It is widely expressed in the central nervous system and peripheral tissues. Studies have shown that Nogo-B binds to three different receptors; Nogo receptor-1 (NgRl), Nogo-B specific receptor (NgBR) and paired immunoglobulin like receptor B(PirB). These receptors play a dual role of suppression and promotion in angiogenesis, proliferation and apoptosis, invasion and migration, which are important events in tumor development and progression, through various post-receptor signaling pathways, including RhoA/Rho- associated coiled-coil contaning protein kinase (RhoA/ROCK), phosphatidylinositol 3-kinase/protein kinase B (PI3K/ Akt), adenosine 5-monophosphate-activated protein kinase α/liver X receptor α(AMPAa/LXRα), extracellular signal- regulated kinase (ERK), epithelial-mesenchymal transition (EMT), unfolded protein response (UPR) and so on. An in- depth understanding of the mechanisms by which Nogo-B receptors are involved in tumor pathogenesis will provide new insights into the development of drugs. Here, we will summarize the up-to-date researches on the basic structure and expression of Nogo-B/Nogo-B receptors and the suppressing/activating effects of post-receptor signaling pathways in the pathogenesis of malignant solid tumors.