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Macrophage adenosine monophosphate-activated protein kinase (AMPK) limits the development of experimental colitis. AMPK activation inhibits NADPH oxidase (NOX) 2 expression, reactive oxygen species (ROS) generation, and pro-inflammatory cytokine secretion in macrophages during inflammation, while increased NOX2 expression is reported in experimental models of colitis and inflammatory bowel disease (IBD) patients. Although there are reductions in AMPK activity in IBD, it remains unclear whether targeted inhibition of NOX2 in the presence of defective AMPK can reduce the severity of colitis. Here, we investigate whether the inhibition of NOX2 ameliorates colitis in mice independent of AMPK activation. Our study identified that VAS2870 (a pan-Nox inhibitor) alleviated dextran sodium sulfate (DSS)-induced colitis in macrophage-specific AMPKβ1-deficient (AMPKβ1LysM) mice. Additionally, VAS2870 blocked LPS-induced TLR-4 and NOX2 expression, ROS production, nuclear translocation of NF-κB, and pro-inflammatory cytokine secretion in bone marrow-derived macrophages (BMDMs) from AMPKβ1LysM mice, whereas sodium salicylate (SS; AMPK β1 activator) did not. Both VAS2870 and SS inhibited LPS-induced NOX2 expression, ROS production, and pro-inflammatory cytokine secretions in bone marrow-derived macrophages (BMDMs) from wildtype (AMPKβ1fl/fl) mice but only VAS2870 inhibited these effects of LPSs in AMPKβ1LysM BMDMs. Furthermore, in macrophage cells (RAW 264.7), both SS and VAS2870 inhibited ROS production and the secretion of pro-inflammatory cytokines and reversed the impaired autophagy induced by LPSs. These data suggest that inhibiting NOX2 can reduce inflammation independent of AMPK in colitis.

Background/Purpose: Type 2 diabetes and obesity increase the risk of developing colorectal cancer. Metformin may reduce colorectal cancer but the mechanisms mediating this effect remain unclear. In mice and humans, a high-fat diet (HFD), obesity and metformin are known to alter the gut microbiome but whether this is important for influencing tumor growth is not known. Methods: Mice with syngeneic MC38 colon adenocarcinomas were treated with metformin or feces obtained from control or metformin treated mice. Results: We find that compared to chow-fed controls, tumor growth is increased when mice are fed a HFD and that this acceleration of tumor growth can be partially recapitulated through transfer of the fecal microbiome or in vitro treatment of cells with fecal filtrates from HFD-fed animals. Treatment of HFD-fed mice with orally ingested, but not intraperitoneally injected, metformin suppresses tumor growth and increases the expression of short-chain fatty acid (SCFA)-producing microbes Alistipes, Lachnospiraceae and Ruminococcaceae. The transfer of the gut microbiome from mice treated orally with metformin to drug naïve, conventionalized HFD-fed mice increases circulating propionate and butyrate, reduces tumor proliferation, and suppresses the expression of sterol response element binding protein (SREBP) gene targets in the tumor. Conclusion: These data indicate that in obese mice fed a HFD, metformin reduces tumor burden through changes in the gut microbiome.

Breast cancer: Trapping tumors in place Drugs that inhibit two protein-digesting enzymes could offer potent protection against tumor growth and metastasis in an aggressive form of breast cancer. “Triple-negative breast cancer” (TNBC), which lacks three common tumor biomarkers, carries a poor prognosis for patients, with few treatment options. Enzymes that degrade the protein matrix that anchors tumor cells play a prominent role in metastasis. Researchers led by Jung Ae Kim and Byeong-Seon Jeong at Yeungnam University, Gyeongsan, South Korea, have demonstrated that these enzymes offer potential therapeutic exploitation. The researchers identified a compound that simultaneously suppresses the activity of two different matrix-digesting enzymes. This parallel inhibition markedly reduced tumor growth and metastatic invasion in mouse models of TNBC, with minimal toxicity to non-cancerous cells. This approach could thus offer new hope for treating a challenging class of tumors.

Background: Avipattikar churna, a poly-herbal formulation, is one of the popular ayurvedic formulations which is used for peptic ulcer diseases but the scientific documentation with regards to its effect for the indication is lacking. Aims: This study was carried out to evaluate the anti-secretory and the anti-ulcerogenic activities of the churna and to compare its activity with that of ranitidine in a pyloric ligated model of rats. Material and methods: Four groups of rats with 6 animals in each served as the ulcer controls, churna low dose (500 mg/ kg), churna high dose (750mg/kg) and ranitidine (25mg/kg). The control group rats received only vehicle (2% (v/v) gum acacia), while the rats of the other groups received the respective dose of the churna or ranitidine which was suspended in the vehicle. The treatments were given twice a day, orally, for two days. After 1 hour of the last dose, pyloric ligations were performed and the rats were sacrificed for evaluation after four hours of the ligations. The gastric contents were collected and its volume, pH and acidity were measured. The numbers of ulcers and their lengths were measured which were used to calculate the gastric irritancy index and the curative ratio. The histological examinations of the gastric tissues were also performed. Results: The churna, in both doses, significantly decreased the volumes of the gastric contents, the ulcer score, the length of the ulcer, the gastric irritancy index and pH increased as compared to those in the control group. The effects of the churna were comparable to that of ranitidine. The histopathological evaluation of the gastric tissue also supported the results. Conclusion: Avipattikar churna has anti-secretory and antiulcerogenic effects which are comparable to those of ranitidine in peptic ulcer diseases.

5-Hydroxytryptamine (5-HT) induces proliferation of cancer cells and vascular cells. In addition to 5-HT production by several cancer cells including gastrointestinal and breast cancer, a significant level of 5-HT is released from activated platelets in the thrombotic environment of tumors, suggesting that inhibition of 5-HT signaling may constitute a new target for antiangiogenic anticancer drug discovery. In the current study we clearly demonstrate that 5-HT-induced angiogenesis was mediated through the 5-HT1 receptor-linked Gβγ/Src/PI3K pathway, but not through the MAPK/ERK/p38 pathway. In addition, 5-HT induced production of NADPH oxidase (NOX)-derived reactive oxygen species (ROS). In an effort to develop new molecularly targeted anticancer agents against 5-HT action in tumor growth, we demonstrate that BJ-1108, a derivative of 6-amino-2,4,5-trimethylpyridin-3-ol, significantly inhibited 5-HT-induced angiogenesis. In addition, BJ-1108 induced a significant reduction in the size and weight of excised tumors in breast cancer cell-inoculated CAM assay, showing proportionate suppression of tumor growth along with inhibition of angiogenesis. In human umbilical vein endothelial cells (HUVECs), BJ-1108 significantly suppressed 5-HT-induced ROS generation and phosphorylation of PI3K/Akt but not of Src. Unlike NOX inhibitors, BJ-1108, which showed better antioxidant activity than vitamin C, barely suppressed superoxide anion induced by mevalonate or geranylgeranyl pyrophosphate which directly activates NOX without help from other signaling molecules in HUVECs, implying that the anti-angiogenic action of BJ-1108 was not mediated through direct action on NOX activation, or free radical scavenging activity. In conclusion, BJ-1108 inhibited 5-HT-induced angiogenesis through PI3K/NOX signaling but not through Src, ERK, or p38.