Patients with EGFR mutations in non-small cell lung cancer (NSCLC) have been greatly benefited from gefitinib, however, the therapeutic has failed due to the presence of acquired resistance. In this study, we show that gefitinib significantly induces downregulation of Sterol Regulator Element Binding (SREBP1) in therapy-sensitive cells. However, this was not observed in EGFR mutant NSCLC cells with acquired resistance. Lipidomics analysis showed that gefitinib could differently change the proportion of saturated phospholipids and unsaturated phospholipids in gefitinib-sensitive and acquired-resistant cells. Besides, levels of ROS and MDA were increased upon SREBP1 inhibition and even more upon gefitinib treatment. Importantly, inhibition of SREBP1 sensitizes EGFR-mutant therapy-resistant NSCLC to gefitinib both in vitro and in vivo models. These data suggest that sustained de novo lipogenesis through the maintenance of active SRBEP-1 is a key feature of acquired resistance to gefitinib in EGFR mutant lung cancer. Taken together, targeting SREBP1-induced lipogenesis is a promising approach to overcome acquired resistance to gefitinib in EGFR-mutant lung cancer.
Salvia miltiorrhiza is one of the most commonly used traditional Chinese medicines in the treatment of cardiovascular and cerebrovascular diseases. Cryptotanshinone (CTS), tanshinone IIA (Tan IIA), dihydrotanshinone I (diTan I), and tanshinone I (Tan I) are the main active compounds in the liposoluble extract of Salvia miltiorrhiza. The differences in the pharmacokinetic and tissue distribution behaviors of the four tanshinones after oral administration of the liposoluble extract of Salvia miltiorrhiza and pure compounds are not clear. This study aims to compare the pharmacokinetics and tissue distribution of the four tanshinones after oral administration of pure tanshinone monomers and the liposoluble extract of Salvia miltiorrhiza. An ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis method was developed for the determination of the four tanshinones. Theresults showed that the AUC and C max of tanshinones in rats receiving the extract of Salvia miltiorrhiza were significantly increased compared with those receiving the pure tanshinones. In the tissue distribution experiments, the AUC of the four tanshinones in the extract was much greater than the AUC of the monomers in the lung, heart, kidney, liver, and brain, and the coexisting constituents particularly promoted the distribution of tanshinones into tissues that the drug cannot sufficiently penetrate. These findings suggested that the coexisting constituents in the liposoluble extract of Salvia miltiorrhiza play an important role in the alteration of plasma concentration and tissue distribution of the four tanshinones. Understanding these differences could be of significance for the development and application of Salvia miltiorrhiza extract and tanshinone components.
Cryptotanshinone (CTS) is a lipophilic constituent of Salvia miltiorrhiza, with a broad-spectrum anticancer activity. We have observed that CTS enhances the efficacy of gefitinib in human lung cancer H1975 cells, yet little is known about its molecular mechanism. To explore how CTS enhances H1975 cell sensitivity to gefitinib, we figured out differential proteins of H1975 cells treated by gefitinib alone or in combination with CTS using label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS). Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein–protein interaction (PPI) bioinformatic analyses of the differential proteins were performed. CTS enhanced H1975 cell sensitivity to gefitinib in vitro and in vivo, with 115 and 128 differential proteins identified, respectively. GO enrichment, KEGG analysis, and PPI network comprehensively demonstrated that CTS mainly impacted the redox process and fatty acid metabolism in H1975 cells. Moreover, three differential proteins, namely, catalase (CAT), heme oxygenase 1 (HMOX1), and stearoyl-CoA desaturase (SCD) were validated by RT-qPCR and Western blot. In conclusion, we used a proteomic method to study the mechanism of CTS enhancing gefitinib sensitivity in H1975 cells. Our finding reveals the potential protein targets of CTS in overcoming gefitinib resistance, which may be therapeutical targets in lung cancer.
version includes a concrete description of the strategy design and gives quantitative extension of conducting sampling vectors. Besides, the outdoor system evaluation is appended to further validate our tracking strategy.
Focusing on the unreliable sensing phenomenon in wireless sensor networks and its impact on target-tracking accuracy, this paper first analyzes the uncertain area and its boundaries. Then the monitor area can be divided into faces by these uncertain boundaries and each face has an identical signature vector. On the other hand, for each target localization, any pair-wise nodes' RSS is ordinal or flipped can be determined by multiple grouping samplings and the sampling vector is built. Hence, the Fault-Tolerant Target-Tracking (FTTT) strategy is proposed, which transforms the tracking problem into a vector matching process in order to improve the tracking flexibility, increase the tracking accuracy and reduce the influence of in-the-filed factors. In addition, a heuristic matching algorithm is introduced to reduce the computational complexity. Results have shown that FTTT is more flexible and has higher tracking accuracy than congenerous methods.
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