Breast carcinoma is the most common female cancer with considerable metastatic potential. Signal transducers and activators of the transcription 3 (Stat3) signaling pathway is constitutively activated in many cancers including breast cancer and has been validated as a novel potential anticancer target. Here, we reported our finding with nifuroxazide, an antidiarrheal agent identified as a potent inhibitor of Stat3. The potency of nifuroxazide on breast cancer was assessed in vitro and in vivo. In this investigation, we found that nifuroxazide decreased the viability of three breast cancer cell lines and induced apoptosis of cancer cells in a dose-dependent manner. In addition, western blot analysis demonstrated that the occurrence of its apoptosis was associated with activation of cleaved caspases-3 and Bax, downregulation of Bcl-2. Moreover, nifuroxazide markedly blocked cancer cell migration and invasion, and the reduction of phosphorylated-Stat3Tyr705, matrix metalloproteinase (MMP) MMP-2 and MMP-9 expression were also observed. Furthermore, in our animal experiments, intraperitoneal administration of 50 mg/kg/day nifuroxazide suppressed 4T1 tumor growth and blocked formation of pulmonary metastases without detectable toxicity. Meanwhile, histological and immunohistochemical analyses revealed a decrease in Ki-67-positive cells, MMP-9-positive cells and an increase in cleaved caspase-3-positive cells upon nifuroxazide. Notably, nifuroxazide reduced the number of myeloid-derived suppressor cell in the lung. Our data indicated that nifuroxazide may potentially be a therapeutic agent for growth and metastasis of breast cancer.
Human dihydroorotate dehydrogenase (DHODH) is a flavin-dependent mitochondrial enzyme catalyzing the fourth step in the de novo pyrimidine synthesis pathway. It is originally a target for the treatment of the non-neoplastic diseases involving in rheumatoid arthritis and multiple sclerosis, and is re-emerging as a validated therapeutic target for cancer therapy. In this review, we mainly unravel the biological function of DHODH in tumor progression, including its crucial role in de novo pyrimidine synthesis and mitochondrial respiratory chain in cancer cells. Moreover, various DHODH inhibitors developing in the past decades are also been displayed, and the specific mechanism between DHODH and its additional effects are illustrated. Collectively, we detailly discuss the association between DHODH and tumors in recent years here, and believe it will provide significant evidences and potential strategies for utilizing DHODH as a potential target in preclinical and clinical cancer therapies.
Epidemiological studies have shown that an elevated uric acid (UA) level predicts the development of metabolic syndrome and diabetes; however, there is no direct evidence of this, and the underlying mechanism remains unclear. Here, we showed that a high-UA diet triggered the expression of pro-inflammatory cytokines, activated the NF-κB pathway, and increased gliosis in the hypothalamus. Intracerebroventricular injection of UA induced hypothalamic inflammation and reactive gliosis, whereas these effects were markedly ameliorated by the inhibition of NF-κB. Moreover, magnetic resonance imaging confirmed that hyperuricemia in rodents and humans was associated with gliosis in the mediobasal hypothalamus. Importantly, the rats administered UA exhibited dyslipidemia and glucose intolerance, which were probably mediated by hypothalamic inflammation and hypothalamic neuroendocrine alterations. These results suggest that UA can cause hypothalamic inflammation via NF-κB signaling. Our findings provide a potential therapeutic strategy for UA-induced metabolic disorders.
Uric acid (UA) is a purine metabolite that in most mammals is degraded by the hepatic enzyme uricase to allantoin. Epidemiological studies have shown that an elevated UA level predicts the development of cognition and memory deficits; however, there is no direct evidence of this relationship, and the underlying mechanism is largely undefined. Here, we show that a high-UA diet triggers the expression of proinflammatory cytokines, activates the Toll-like receptor 4 (TLR4)/nuclear factor (NF)-B pathway, and increases gliosis in the hippocampus of Wistar rats. We, subsequently, identify a specific inhibitor of NF-B, BAY11-7085, and show that stereotactic injections of the inhibitor markedly ameliorate UA-induced hippocampal inflammation and memory deficits in C57BL/6 mice. We also found that NF-B is activated in the primary cultured hippocampal cells after UA administration. Additionally, C57BL/6 mice that lack TLR4 are substantially protected against UA-induced cognitive dysfunction, possibly due to a decrease in inflammatory gene expression in the hippocampus. Importantly, magnetic resonance imaging confirms that hyperuricemia in rats and humans is associated with gliosis in the hippocampus. Together, these results suggest that UA can cause hippocampal inflammation via the TLR4/NF-B pathway, resulting in cognitive dysfunction. Our findings provide a potential therapeutic strategy for counteracting UA-induced neurodegeneration.
Human dihydroorotate dehydrogenase (hDHODH) is an attractive target for cancer therapy. Based on its crystal structure, we designed and synthesized a focused compound library containing the structural moiety of 1,4-benzoquinone, which possesses reactive oxygen species (ROS) induction capacity. Compound 3s with a naphtho[2,3-d][1,2,3]triazole-4,9-dione scaffold exhibited inhibitory activity against hDHODH. Further optimization led to compounds 11k and 11l, which inhibited hDHODH activity with IC50 values of 9 and 4.5 nM, respectively. Protein–ligand cocrystal structures clearly depicted hydrogen bond and hydrophobic interactions of 11k and 11l with hDHODH. Compounds 11k and 11l significantly inhibited leukemia cell and solid tumor cell proliferation and induced ROS production, mitochondrial dysfunction, apoptosis, and cell cycle arrest. Nanocrystallization of compound 11l displayed significant in vivo antitumor effects in the Raji xenograft model. Overall, this study provides a novel bifunctional compound 11l with hDHODH inhibition and ROS induction efficacy, which represents a promising anticancer lead worthy of further exploration.
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