Reactive oxygen species (ROS) have a crucial role in melanoma differentiation-associated gene-7 (MDA-7)/interleukin-24 (IL-24)-induced cancer cell apoptosis. However, cancer cell has a series of protective mechanisms to resist ROS damage. Nuclear factor erythroid 2-related factor 2 (Nrf2) activates antioxidant response element (ARE)-mediated gene expression involved in cellular protection against oxidative stress. As the Nrf2 repressor, Kelch-like ECH-associated protein-1 (Keap1) sequesters Nrf2 in cytoplasm to block Nrf2 nuclear translocation. In the present study, administration of MDA-7/IL-24 by means of tumor-selective replicating adenovirus (ZD55-IL-24) was used to investigate whether ZD55-IL-24 could attenuate Nrf2-mediated oxidative stress response in cancer cell. We found that ZD55-IL-24 effectively strengthened the association between Nrf2 and Keap1 to restrict Nrf2 nuclear translocation, thereby inhibiting ARE-dependent transcriptional response. To evaluate the detailed mechanism underlying the suppression of ZD55-IL-24 on Nrf2-mediated oxidative stress response, we further tested three different mitogen-activated protein kinase (MAPK) signaling pathways in A549 and HeLa cells transfected by ZD55-IL-24. Our data showed that ZD55-IL-24 inhibited extracellular signal-regulated kinase (ERK) signal pathway but activated p38 and c-Jun-NH2-kinase (JNK) signal pathways to exert the tumor-specific apoptosis. Moreover, ERK pathway inhibitor U0126 prevented Nrf2 phosphorylation at Ser40 to retard Nrf2 nuclear translocation, thus decreasing antioxidant gene transcription. In contrast, p38 pathway inhibitor SB203580 obviously promoted the dissociation of Nrf2 from Keap1 to promote antioxidant gene transcription. However, JNK pathway had no effect on Nrf2 subcellular localization or the association of Nrf2 with Keap1. Conclusively, our results indicate that ZD55-IL-24 inhibits Nrf2-mediated oxidative stress response not only by activating p38 signal pathway to potentiate the association of Nrf2 and Keap1 but also by suppressing ERK signal pathway to postpone Nrf2 nuclear translocation. Given the 'dark' side of Nrf2 on carcinoma cell survival and chemoresistance, our study provides a novel explanation about MDA-7/IL-24-induced cancer-specific apoptosis and therapeutic sensitization through suppression of the cytoprotective system.
Hepatocellular carcinoma is the most common primary malignancy of the liver. The chemotherapeutic drug cisplatin is widely used for advanced liver cancer. However, the development of cisplatin resistance in cancer cells, which is related to the decreased cellular susceptibility to apoptosis, results in a major limitation of cisplatin-based chemotherapy. Recently, triggering necroptosis has been proposed to be a novel therapeutic strategy to eradicate apoptosis-resistant cancer cells. In this study, we provided evidence that cisplatin could induce cell death in HepG2 cells, but not in the apoptosis-resistant HepG2/DDP cells. Ectopic expression of RIP3 promoted cisplatin-induced HepG2/DDP cells death, HMGB1 and LDH release. Moreover, we demonstrated that this type of cell death was necroptosis and depended on RIP1-RIP3-MLKL signaling pathway because inhibition of MLKL activity by necrosulfonamide (NSA) or knockdown of RIP1 significantly attenuated cisplatin-induced cell death in HepG2/DDP-RIP3 cells. Finally, we found that ectopic expression of RIP3 sensitized HepG2/DDP cancer cells to cisplatin treatment in vivo. The findings offer new insights into the molecular mechanisms underlying cisplatin-induced necroptosis in liver cancer cells and suggest that combination of cisplatin with other drugs which can restore RIP3 expression in cancer cells maybe a better choice for therapy of apoptosis-resistant cancer.
Introduction: Chuanxiong, a traditional Chinese medicine, has been proved to treat a variety of cardiovascular and cerebrovascular diseases by promoting angiogenesis. However, the mechanisms of Chuanxiong’s pro-angiogenesis is currently unknown. This study aimed to uncover the effect and mechanisms of Chuanxiong promoting angiogenesis in vivo and in vitro.Methods: First, potential targets were predicted by network pharmacology analysis, and PPI network was established and the pathways were enriched. Then, the chorioallantoic membrane test on quails was applied to assess the proangiogenic effects in vivo. As well, to evaluate the effects in vitro, real-time PCR, western blot analysis, the scratch test, and the tube formation experiment were used. Subsequently, the major metabolic pathways were analyzed using non-targeted metabolomics.Results: As a result of network pharmacological analysis, 51 collective targets of Chuanxiong and angiogenesis were identified, which are mainly associated with PI3K/AKT/Ras/MAPK pathway. And the biological verification results showed that Chuanxiong could increase the vessel numbers and vessel area in qCAM models. Meanwhile, Chuanxiong contributed to HUVEC proliferation, tube formation, migration, by encouraging scratch healing rates and boosting tube branch points. In addition, the levels of VEGFR2, MAPK and PI3K were elevated compared to the control group. The western blot analysis also confirmed Chuanxiong could promote an increase in AKT, FOXO1 and Ras. Furtheremore, metabolomic results showed that the proangiogenic effect of Chuanxiong is associated with glycine, serine and threonine metabolism.Discussion: In conclusion, this study clarified that Chuanxiong could promote angiogenesis in vivo and in vitro via regulating PI3K/AKT/Ras/MAPK pathway.
19Current evidence to support extensive use of probiotics in inflammatory bowel disease is 20 limited and factors contribute to the inconsistent effectiveness of clinical probiotic therapy are 21 not completely known. Here, as a proof-of-concept, we utilized Bifidobacterium longum JDM 22 301, a widely used commercial probiotic strain in China, to study potential factors that may 23 influence the beneficial effect of probiotics in experimental colitis. We found that the probiotic 24 therapeutic effect was varied across individual mouse even with the same genetic background 25 and consuming the same type of food. The different probiotic efficacy was highly correlated 26 with different microbiome features in each mouse. Consumption of a diet rich in fat can change 27 the host sensitivity to mucosal injury-induced colitis but did not change the host responsiveness 28 to probiotic therapy. Finally, the host genetic factor TLR2 was required for a therapeutic effect 29 of B. longum JDM 301. Together, our results suggest that personalized microbiome and genetic 30 features may modify the probiotic therapeutic effect.31
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