Atractylenolide III Attenuates Angiogenesis in Gastric Precancerous Lesions Through the Downregulation of Delta-Like Ligand 4.

Background: Blocking and even reversing gastric precancerous lesions (GPL) is a key measure to lower the incidence of gastric cancer. Atractylenolide III (AT-III) is a mainly active component of the Atractylodes rhizome and has been widely used in tumor treatment. However, the effects of AT-III on GPL and its mechanisms have not been reported. Methods: H & E staining and AB-PAS staining were employed to evaluate the histopathology in the gastric mucosa. In parallel, CD34 immunostaining was performed for angiogenesis assessment, and transmission electron microscope for microvessel ultrastructural observation. Investigation for the possible mechanism in vivo and in vitro was conducted using immunohistochemistry, RT-qPCR and western blotting. Results: In most GPL specimens, AT-III treatment reduced microvascular abnormalities and attenuated early angiogenesis, with the regression of most intestinal metaplasia and partial dysplasia. Meanwhile, the expression of VEGF-A and HIF-1α was enhanced in GPL samples of model rats, and their expressions were decreased in AT-III-treated GPL rats. Moreover, DLL4 mRNA and protein expression were higher in GPL rats than in control rats. DLL4 protein expression was significantly enhanced in human GPL tissues. In addition, AT-III treatment could diminish DLL4 mRNA level and protein expression in the MNNG-induced GPL rats. In vitro study showed that in AGS and HGC-27 cells, DLL4 mRNA level and protein expression were significantly decreased after AT-III treatment. However, AT-III had no significant regulatory effect on Notch1 and Notch4. Conclusion: AT-III treatment is beneficial in lessening gastric precancerous lesions and attenuating angiogenesis in rats, and that may be contributed by the decrease of angiogenesis-associated HIF-1α and VEGF-A, and downregulation of DLL4.

Ginsenoside Rg3 inhibits angiogenesis in gastric precancerous lesions through downregulation of Glut1 and Glut4.

Ginsenoside Rg3 (GRg3) is a ginsenoside extracted from Panax ginseng. GRg3 displays multiple pharmacological properties, such as antitumor, anti-inflammatory, antioxidative and antifibrotic properties. However, whether GRg3 inhibits angiogenesis in gastric precancerous lesions (GPLs) and the possible mechanisms remain unknown. GRg3 attenuated gastric intestinal metaplasia and gastric dysplasia, the hallmark of GPL pathology, in rats with MNNG-ammonia compound induced GPLs. Increased CD34+ microvessel density and VEGF expression, which indicate the presence of angiogenesis, were evident in the rats with GPLs. GRg3 administration reduced VEGF protein expression and CD34+ microvessel density. In addition, GRg3 was capable of attenuating microvascular abnormalities. Data analysis revealed that enhanced protein expression of GLUT1, GLUT3 and GLUT4 were present in both human and animal GPL specimens. The administration of GRg3 caused significant decreases in the mRNA and protein expression levels of GLUT1 and GLUT4 in the rats with GPLs. However, the GRg3-treated rats with GPLs did not demonstrate regulatory effects on GLUT3, GLUT6, GLUT10, and GLUT12. Consistent with in vitro results, GRg3 administration significantly reduced the protein expression levels of GLUT1 and GLUT4 in both AGS and HGC-27 human gastric cancer cells in vitro. In conclusion, GRg3 can attenuate angiogenesis and temper microvascular abnormalities in rats with GPLs, which may be associated with its inhibition on the aberrant activation of GLUT1 and GLUT4.

Ginsenoside Rb1 Lessens Gastric Precancerous Lesions by Interfering With ß-Catenin/TCF4 Interaction.

Background: Seeking novel and effective therapies for gastric precancerous lesions (GPL) is crucial to reducing the incidence of gastric cancer. Ginsenoside Rb1 (GRb1) is a major ginsenoside in ginseng and has been proved to possess multiple bioactivities. However, whether GRb1 could protect against GPL and the underlying mechanisms have not been explored. Methods: We evaluated the effects of GRb1 on gastric precancerous lesions in rats on macroscopic, microscopic and ultramicroscopic levels. Then, an antibody array was employed to screen differential expression proteins (DEPs). Validation for the targeting DEP and investigation for the possible mechanism was conducted using immunohistochemistry, qRT-PCR, TUNEL apoptosis assay, immunoprecipitation and immunoblotting. Results: GRb1 was found to reverse intestinal metaplasia and a portion of dysplasia in the MNNG-induced GPL rats. The antibody array assay revealed seven DEPs in GPL rats as compared to control rats (5 DEPs were up-regulated, while two DEPs were down-regulated). Among the DEPs, ß-catenin, beta-NGF and FSTL1 were significantly down-regulated after GRb1 administration. Our validation results revealed that enhanced protein expression and nuclear translocation of ß-catenin were present in animal GPL samples. In addition, analysis of human gastric specimens demonstrated that ß-catenin up-regulation and nuclear translocation were significantly associated with advanced GPL pathology. GRb1 intervention not only decreased protein expression and nuclear translocation of ß-catenin, but interfered with ß-catenin/TCF4 interaction. Along with this, declined transcriptional and protein expression levels of downstream target genes including c-myc, cyclin D1 and Birc5 were observed in GRb1-treated GPL rats. Conclusion: GRb1 is capable of preventing the occurrence and progression of GPL, which might be contributed by diminishing protein expression and nuclear translocation of ß-catenin and interfering with ß-catenin/TCF4 interaction.