Ru(II)-based complexes containing 2-thiouracil derivatives suppress liver cancer stem cells by targeting NF-κB and Akt/mTOR signaling.

Cancer stem cells (CSCs) are defined as a rare population of cancer cells related to tumor initiation and maintenance. These cells are primarily responsible for tumor growth, invasion, metastasis, recurrence, and resistance to chemotherapy. In this paper, we demonstrated the ability of Ru(II)-based complexes containing 2-thiouracil derivatives with the chemical formulas trans-[Ru(2TU)(PPh3)2(bipy)]PF6 (1) and trans-[Ru(6m2TU)(PPh3)2(bipy)]PF6 (2) (where 2TU = 2-thiouracil and 6m2TU = 6-methyl-2-thiouracil) to suppress liver CSCs by targeting NF-κB and Akt/mTOR signaling. Complexes 1 and 2 displayed potent cytotoxic effects on cancer cell lines and suppressed liver CSCs from HepG2 cells. Increased phosphatidylserine exposure, loss of mitochondrial transmembrane potential, increased PARP (Asp214) cleavage, DNA fragmentation, chromatin condensation and cytoplasmic shrinkage were detected in HepG2 cells treated with these complexes. Mechanistically, complexes 1 and 2 target NF-κB and Akt/mTOR signaling in HepG2 cells. Cell motility inhibition was also detected in HepG2 cells treated with these complexes. Complexes 1 and 2 also inhibited tumor progression in mice with HepG2 cell xenografts and exhibited tolerable systemic toxicity. Taken together, these results indicate that these complexes are new anti-HCC drug candidates that can suppress liver CSCs.

Blockade of cannabinoid receptors reduces inflammation, leukocyte accumulation and neovascularization in a model of sponge-induced inflammatory angiogenesis.

OBJECTIVE: Angiogenesis depends on a complex interaction between cellular networks and mediators. The endocannabinoid system and its receptors have been shown to play a role in models of inflammation. Here, we investigated whether blockade of cannabinoid receptors may interfere with inflammatory angiogenesis. MATERIALS AND METHODS: Polyester-polyurethane sponges were implanted in C57Bl/6j mice. Animals received doses (3 and 10 mg/kg/daily, s.c.) of the cannabinoid receptor antagonists SR141716A (CB1) or SR144528 (CB2). Implants were collected at days 7 and 14 for cytokines, hemoglobin, myeloperoxidase, and N-acetylglucosaminidase measurements, as indices of inflammation, angiogenesis, neutrophil and macrophage accumulation, respectively. Histological and morphometric analysis were also performed. RESULTS: Cannabinoid receptors expression in implants was detected from day 4 after implantation. Treatment with CB1 or CB2 receptor antagonists reduced cellular influx into sponges at days 7 and 14 after implantation, although CB1 receptor antagonist were more effective at blocking leukocyte accumulation. There was a reduction in TNF-α, VEGF, CXCL1/KC, CCL2/JE, and CCL3/MIP-1α levels, with increase in CCL5/RANTES. Both treatments reduced neovascularization. Dual blockade of cannabinoid receptors resulted in maximum inhibition of inflammatory angiogenesis. CONCLUSIONS: Blockade of cannabinoid receptors reduced leukocyte accumulation, inflammation and neovascularization, suggesting an important role of endocannabinoids in sponge-induced inflammatory angiogenesis both via CB1 and CB2 receptors.

Role of the chemokines CCL3/MIP-1 alpha and CCL5/RANTES in sponge-induced inflammatory angiogenesis in mice.

OBJECTIVE: We examined the potential contribution of CCL3 and CCL5 to inflammatory angiogenesis in mice. METHODS: Polyester-polyurethane sponges were implanted in mice and blood vessel counting and hemoglobin, myeloperoxidase and N-acetylglucosaminidase measurements used as indexes for vascularization, neutrophil and macrophage accumulation, respectively. RESULTS: CCL3 and CCL5 were expressed throughout the observation period. Exogenous CCL3 enhanced angiogenesis in WT, but angiogenesis proceeded normally in CCL3(-/-) mice, suggesting that endogenous CCL3 is not critical for sponge-induced angiogenesis in mice. CCL5 expression was detected at day 1, but levels significantly increased thereafter. Exogenous CCL5 reduced angiogenesis in WT mice possible via CCR5 as CCL5 was without an effect in CCR5(-/-) mice. Treatment of WT with the CCR1/CCR5 antagonist, Met-RANTES, prevented neutrophil and macrophage accumulation, but enhanced sponge vascularization. CONCLUSION: Thus, endogenous CCL3 appears not to play a role in driving sponge-induced inflammatory angiogenesis in mice. The effects of CCL5 were anti-angiogenic and appeared to be mediated via activation of CCR5.

Platelet activating factor receptors drive CXC chemokine production, neutrophil influx and edema formation in the lungs of mice injected with Tityus serrulatus venom.

Lung injury is a common finding and a frequent cause of death in cases of severe human envenoming by scorpion sting. The present work investigated the effects of pretreatment with a platelet activation factor receptor (PAFR) antagonist and a CXCR2 inhibitor on the lung injury induced by subcutaneous injection of Tityus serrulatus venom (TsV) in mice. Lung injury was assessed by evaluating the extravasation of Evans blue dye, as an index of increased vascular permeability, the neutrophil accumulation (mieloperoxidase activity), the concentration of tumor necrosis factor-alpha (TNF-alpha) and the chemokine KC in the lung after TsV administration. Neutrophil influx was preceded by the production of KC and dependent on CXCR2, as shown by the ability of repertaxin, a CXCR2 inhibitor, to prevent an increase of MPO activity in the lung. Repertaxin had no effect on TsV-induced lethality. The PAFR antagonist (UK-74,505) significantly reduced TsV-induced vascular permeability changes and neutrophil influx in the lungs. The inhibition of neutrophil influx was associated with inhibition of the production of the CXCR2-active chemokine KC. UK-74,505 had no effect on the lethality induced by TsV. In conclusion, these results show that the influx of neutrophils in the lungs of mice injected with TsV is dependent on the activation of PAFR and on PAFR-dependent production of the chemokine KC as well as activation of CXCR2 on neutrophils. Although lung injury may contribute to late lethality after TsV envenoming, acute lethality is not modified by inhibitors of neutrophil influx.