RNA-binding domain 2 of nucleolin is important for the autophagy induction of curcumol in nasopharyngeal carcinoma cells.

BACKGROUND & AIMS: Excessive autophagy induces cell death and is regarded as the treatment of cancer therapy. We have confirmed that the anti-cancer mechanism of curcumol is related to autophagy induction. As the main target protein of curcumol, RNA binding protein nucleolin (NCL) interacted with many tumor promoters accelerating tumor progression. However, the role of NCL in cancer autophagy and in curcumol's anti-tumor effects haven't elucidated. The purpose of the study is to identify the role of NCL in nasopharyngeal carcinoma autophagy and reveal the immanent mechanisms of NCL played in cell autophagy. METHODS & RESULTS: In the current study, we have found that NCL was markedly upregulated in nasopharyngeal carcinoma (NPC) cells. NCL overexpression effectively attenuated the level of autophagy in NPC cells, and NCL silence or curcumol treatment obviously aggravated the autophagy of NPC cells. Moreover, the attenuation of NCL by curcumol lead a significant suppression on PI3K/AKT/mTOR signaling pathway in NPC cells. Mechanistically, NCL was found to be directly interact with AKT and accelerate AKT phosphorylation, which caused the activation of the PI3K/AKT/mTOR pathway. Meanwhile, the RNA Binding Domain (RBD) 2 of NCL interacts with Akt, which was also influenced by curcumol. Notably, the RBDs of NCL delivered AKT expression was related with cell autophagy in the NPC. CONCLUSION: The results demonstrated that NCL regulated cell autophagy was related with interaction of NCL and Akt in NPC cells. The expression of NCL play an important role in autophagy induction and further found that was associated with its effect on NCL RNA-binding domain 2. This study may provide a new perspective on the target protein studies for natural medicines and confirm the effect of curcumol not only regulating the expression of its target protein, but also influencing the function domain of its target protein.

Osthole Induces Apoptosis and Caspase-3/GSDME-Dependent Pyroptosis via NQO1-Mediated ROS Generation in HeLa Cells.

Osthole is a natural coumarin which has been proved to inhibit growth of cancer cells by inducing cell death, while its mechanism was considered to be just caused by apoptosis. In our study, we found that osthole activated not just apoptosis, but also pyroptosis which is a form of regulated cell death accompanied by loss of cell membrane integrity and lactate dehydrogenase (LDH) release. Caspase-3 is a key protein of apoptosis as well as pyroptosis. The apoptosis and pyroptosis induced by osthole were all inhibited by irreversible caspase-3 inhibitor Z-DEVD-FMK. Meanwhile, knockdown of gasdermin E (GSDME) only reduced the osthole-induced pyroptosis but did not affect the occurrence of apoptosis. Our proteomic analysis revealed that the expression of NAD(P)H: quinone oxidoreductase 1 (NQO1) was decreased in osthole-treated cells. Moreover, NQO1 inhibition by osthole induced the overproduction of reactive oxygen species (ROS), as well as apoptosis and pyroptosis. ROS inhibitor N-Acetyl-L-cysteine (NAC) not only reduced osthole-induced apoptosis but also reversed its effect on the pyroptosis. Meanwhile, knockdown of NQO1 by si-NQO1 or its inhibitor dicoumarol (DIC) not only enhanced ROS generation but also strengthened the GSDME-mediated pyroptosis. Finally, we demonstrated that osthole inhibited tumor growth and the expression of NQO1 in a HeLa xenograft mode. Similar to the results in vitro, osthole stimulated the activation of caspase-3, PARP, and GSDME in vivo. Taken together, all these data suggested that osthole induced apoptosis and caspase-3/GSDME-mediated pyroptosis via NQO1-mediated ROS accumulation.

Curcumol simultaneously induces both apoptosis and autophagy in human nasopharyngeal carcinoma cells.

Autophagy is usually considered as a protective mechanism against cell death, and in the meantime, leads to cell injury even apoptosis. Apoptosis and autophagy are very closely connected and may cooperate, coexist, or antagonize each other on progressive occurrence of cell death triggered by natural compounds. Therefore, the interplay between the two modes of death is essential for the overall fate of cancer cells. Our previous study revealed that curcumol induced apoptosis in nasopharyngeal carcinoma (NPC) cells. Recently, curcumol was found to induce autophagy in cancer cells. However, whether curcumol can induce NPC cells autophagy and the effects of autophagy on apoptosis remain elusive. In this study, we found that curcumol induced autophagy through AMPK/mTOR pathway in CNE-2 cells. Moreover, inhibiting autophagy by autophagy inhibitor 3-methyladenine (3-MA) or apoptosis inhibitor z-VAD-fmk significantly increased proliferation while attenuated apoptosis and autophagy compared with the curcumol 212 µM group. In contrast, combining curcumol with autophagy agonist rapamycin and apoptosis inducer MG132 synergized the apoptotic and autophagic effect of curcumol. Taken together, our study demonstrates that curcumol promotes autophagy in NPC via AMPK/mTOR pathway, induces autophagy enhances the activity of curcumol in NPC cells; the combination of autophagy inducer and curcumol can be a new therapeutic strategy for NPC.

Mogroside V reduce OVA-induced pulmonary inflammation based on lung and serum metabolomics.

BACKGROUND: Mogroside V, the main ingredient of Siraitia grosvenorii, has been proved to have therapeutic effects on pulmonary diseases. The specific mechanism still remains to be clarified, which hinders the potence of its medicinal value. PURPOSE: Serum and lung metabolomics based on LC-MS analysis were applied to explore the mechanism of mogroside V against lung inflammation. METHOD: In this study, balb/c mice were divided into control, model, mogeoside V and SH groups. We evaluated the protective effects of mogroside V on lung inflammation in asthmatic mice. Suhuang Zhike Jiaonang was used as positive drug. Metabolic profiles of serum and lung samples of mice in control, model and mogroside V groups were analyzed by LC-MS. RESULTS: Administration of mogroside V effectively relieved the expression of biochemical cytokines and lung inflammatory infiltration of asthmatic mice caused by ovalbumin (OVA). And visceral index of mice treated with mogroside V was close to control group. These results indicated that mogroside V ameliorated OVA-induced lung inflammation. LC-MS based metabolomics analysis demonstrated 6 main pathways in asthmatic mice including Vitamin B6 metabolism, Taurine and hypotaurine metabolism, Ascorbate and aldarate metabolism, Histidine metabolism, Pentose and glucuronate interconversions, Citrate cycle (TCA cycle) were regulated after using mogroside V. CONCLUSION: The study firstly elucidates the metabolic pathways regulated by mogroside V on lung inflammation through metabolomics, providing a theoretical basis for more sufficient utilization and compatibility of mogroside V.

Curcumol inhibits EBV-positive Nasopharyngeal carcinoma migration and invasion by targeting nucleolin.

Metastasis is a major cause of recurrence and death in patients with EBV-positive Nasopharyngeal carcinoma (NPC). Previous reports documented that curcumol has both anti-cancer and anti-viral effects, but there is little literature systematically addressing the mechanism of curcumol in EBV-positive tumors. Previously we found that nucelolin (NCL) is a target protein of curcumol in CNE2 cells, an EBV-negative NPC, and in this experiment, we reported a critical role for NCL in promoting migration and invasion of C666-1 cells, an EBV-positive NPC, and found that the expression of NCL determined the level of curcumol's efficacy. Mechanistically, NCL interacted with Epstein-Barr Virus Nuclear Antigen 1 (EBNA1) to activate VEGFA/VEGFR1/PI3K/AKT signaling pathway, which in turn promoted NPC cell invasion and metastasis. Moreover, further study showed that the differential expression of NCL and curcumol intervention only had a regulatory effect on the nuclear accumulation of VEGFR1, which strengthened the anti-cancer effect of curcumol mediated through NCL. Our findings indicated that curcumol exerted anti EBV-positive NPC invasion and metastasis by downregulating EBNA1 and inhibiting VEGFA/VEGFR1/PI3K/AKT signaling by targeting NCL, which provides a novel pharmacological basis for curcumol's clinical use in treating patients with EBV-positive NPC.

Curcumol inhibits the viability and invasion of colorectal cancer cells via miR-30a-5p and Hippo signaling pathway.

MicroRNA-30a-5p (miR-30a-5p), which functions as a tumor suppressor, has been reported to be downregulated in colorectal cancer (CRC) tissues and to be associated with cancer invasion. However, the detailed regulatory mechanism of curcumol in the malignant progression of CRC remains unknown. MTT, Transwell, scratch, western blotting and reverse transcription-quantitative PCR assays were performed to examine how curcumol inhibited CRC cell viability, invasion and migration, and to detect the role of miR-30a-5p and curcumol in the invasion and Hippo signaling pathways of CRC cells. The present study revealed that miR-30a-5p expression was downregulated in human CRC tissues and cells. The results demonstrated that miR-30a-5p downregulation was accompanied by the inactivation of the Hippo signaling pathway, which was demonstrated to promote CRC cell viability, invasion and migration. Curcumol treatment was identified to increase miR-30a-5p expression and to activate the Hippo signaling pathway, which in turn inhibited the invasion and migration of CRC cells. Overexpression of miR-30a-5p enhanced the effects of curcumol on cell invasion and migration, and the Hippo signaling pathway in CRC cells. Furthermore, downregulation of miR-30a-5p reversed the effects of curcumol on cell invasion and migration, and the Hippo signaling pathway in CRC cells. These findings identified novel signaling pathways associated with miR-30a-5p and revealed the effects of curcumol on miR-30a-5p expression. Therefore, curcumol may serve as a potential therapeutic strategy to delay CRC progression.

Luminescent metal-organic frameworks as chemical sensors based on "mechanism-response": a review.

Metal-organic frameworks (MOFs), composed of metal ions/clusters and organic ligands and possessing inherent crystallinity, a definite structure, a tunable pore, and multiple functionalizations, have shown potential for numerous applications. Recently, luminescent MOFs (LMOFs) have attracted much attention as sensing materials because their structural and chemical tunability can afford good selectivity through pore-sieving functions with different pore sizes or host framework-guest interactions. Meanwhile, MOFs with high internal surface areas can concentrate analytes to a high density, thereby decreasing detection limits and exhibiting high sensitivity. Numerous LMOFs have been synthesized and employed for sensing applications. Here, the recent advances of LMOFs as chemical sensors based on "mechanism-response" were summarized, including collapse of frameworks, overlap, cation exchange, ligand exchange, reaction- and redox-based mechanisms, electron transfer, energy transfer, hydrogen bonding, linker-analyte interaction, synergistic effects, and multiple interactions. Moreover, in this review, present challenges and future opportunities in this field are discussed. This review could be a valuable reference for the rational construction and sensing applications of LMOFs.

Osthole induces necroptosis via ROS overproduction in glioma cells.

Glioma is a common primary malignant tumor that has a poor prognosis and often develops drug resistance. The coumarin derivative osthole has previously been reported to induce cancer cell apoptosis. Recently, we found that it could also trigger glioma cell necroptosis, a type of cell death that is usually accompanied with reactive oxygen species (ROS) production. However, the relationship between ROS production and necroptosis induced by osthole has not been fully elucidated. In this study, we found that osthole could induce necroptosis of glioma cell lines U87 and C6; such cell death was distinct from apoptosis induced by MG-132. Expression of necroptosis inhibitor caspase-8 was decreased, and levels of necroptosis proteins receptor-interacting protein 1 (RIP1), RIP3 and mixed lineage kinase domain-like protein were increased in U87 and C6 cells after treatment with osthole, whereas levels of apoptosis-related proteins caspase-3, caspase-7, and caspase-9 were not increased. Lactate dehydrogenase release and flow cytometry assays confirmed that cell death induced by osthole was primarily necrosis. In addition, necroptosis induced by osthole was accompanied by excessive production of ROS, as observed for other necroptosis-inducing reagents. Pretreatment with the RIP1 inhibitor necrostatin-1 attenuated both osthole-induced necroptosis and the production of ROS in U87 cells. Furthermore, the ROS inhibitor N-acetylcysteine decreased osthole-induced necroptosis and growth inhibition. Overall, these findings suggest that osthole induces necroptosis of glioma cells via ROS production and thus may have potential for development into a therapeutic drug for glioma therapy.

PTEN/AKT/mTOR signaling mediates anticancer effects of epigallocatechin­3­gallate in ovarian cancer.

Epigallocatechin­3­gallate (EGCG), a polyphenol present in green tea, exhibits anticancer effects in various types of cancer. A number of studies have focused on the effects of EGCG on lung cancer, but not ovarian cancer. Previous reports have implicated that EGCG suppressed ovarian cancer cell proliferation and induced apoptosis, but its potential anticancer mechanisms and signaling pathways remain unclear. Thus, it is necessary to determine the anti­ovarian cancer effects of EGCG and explore the underlying mechanisms. In the present study, EGCG exerted stronger proliferation inhibition on SKOV3 cells compared with A549 cells and induced apoptosis in SKOV3 cells, as well as upregulated PTEN expression and downregulated the expression of phosphoinositide­dependent kinase­1 (PDK1), phosphor (p)­AKT and p­mTOR. These effects were reversed by the PTEN inhibitor VO­Ohpic trihydrate. The results of the mouse xenograft experiment demonstrated that 50 mg/kg EGCG exhibited increased tumor growth inhibition compared with 5 mg/kg paclitaxel. In addition, PTEN expression was upregulated, whereas the expression levels of PDK1, p­AKT and p­mTOR were downregulated in the EGCG treatment group compared with those in untreated mice in vivo. In conclusion, the results of the present study provided a new underlying mechanism of the effect of EGCG on ovarian cancer and may lead to the development of EGCG as a candidate drug for ovarian cancer therapy.

Lanthanide-Based Metal-Organic Frameworks Containing "V-Shaped" Tetracarboxylate Ligands: Synthesis, Crystal Structures, "Naked-Eye" Luminescent Detection, and Catalytic Properties.

Three lanthanide-based metal-organic frameworks, [Tb(HMDIA)(H2O)3]·H2O (Tb-MDIA), [Ho(HMDIA)(H2O)3]·(H2O)2 (Ho-MDIA), and [Nd(HMDIA)(H2O)3]·(H2O)2 (Nd-MDIA) from the same V-shaped ligand 5,5'-methylenediisophthalic acid (H4MDIA), were prepared by mixing Ln3+ and H4MDIA under solvothermal conditions. The crystal structures of the three complexes were determined by single-crystal X-ray diffraction. The different coordination modes of the organic ligands resulted in different framework structures among the three complexes. The luminescent properties of Ln-MDIA in the ultraviolet-visible region were also studied. Interestingly, the bright-green emitter Tb-MDIA showed high selectivity and sensitivity to allow the naked-eye visualization of Fe3+ ions and picric acid (PA) explosive, and both sensing mechanisms were revealed. Finally, Ho-MDIA and Nd-MDIA were shown to work as heterogeneous catalysts for the cyanosilylation reaction of aromatic aldehydes, and the catalysts could be recycled at least three times without any decrease in activity.

Post-imparting Brønsted acidity into an amino-functionalized MOF as a bifunctional luminescent turn-ON sensor for the detection of aluminum ions and lysine.

A novel aldehyde- and amino-functionalized luminescent metal-organic framework, Cd-TCHO, was constructed through the solvothermal reaction of 4,4',4''-tricarboxytriphenylamine, 2-amino-3-pyridinecarboxaldehyde and cadmium nitrate and was characterized. Post-synthetically oxidizing the aldehyde groups into carboxylate groups afforded a new complex, Cd-TCOOH, and this successful conversion process was confirmed by FT-IR and 1H NMR studies. With the Brønsted acidic sites inside the cavities of Cd-TCOOH, it could be used as a luminescent sensor for Al3+ detection with a high selectivity and sensitivity (LOD = 0.54 ppb), which could be attributed to the coordination between free Brønsted acidic sites and Al3+. Importantly, it could also detect Lys among 20 kinds of natural amino acids; the selectivity, sensitivity and the sensing mechanism are discussed in detail. Also, both of the sensing processes were carried out in the HEPES buffer.

Multifunctional Luminescent Eu(III)-Based Metal-Organic Framework for Sensing Methanol and Detection and Adsorption of Fe(III) Ions in Aqueous Solution.

A novel lanthanide-organic framework (Eu-HODA), consisting of 2,2',3,3'-oxidiphthalic acids as efficient sensitizing units, is assembled and characterized. Eu-HODA features rare chiral helical channels despite the achiral nature of H4ODA. It is found that this MOF shows a unique luminescent response to methanol, in contrast to n-propanol and ethanol. Eu-HODA reveals a turn-off luminescence switching initiated by acetone molecules with an EC50 of 0.03 vol %, which is below the occupational exposure limit of acetone stipulated by the American Conference of Governmental Industrial Hygienists. Furthermore, it also exhibits high sensitivity (Stern-Volmer constant KSV = 2.09 × 104 L/mol) and low detection limit (6.4 ppb) for Fe3+ ions in pure water because of the existence of uncoordinated carboxyl groups within open frameworks. Eu-HODA-based test paper provides a simple and reliable detection method for Fe3+ in practical applications.