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This study evaluates the application of eco-friendly deep eutectic solvents (DESs) in the extraction of phenolic antioxidants from dogbane leaf-tea (DLT). The results showed DESs with lower viscosity allowed an efficient extraction of significantly higher contents of total phenolics or flavonoids. An innovative and high-efficient solvent, choline chloride-levulinic acid (ChCl-LevA), was screened and used in ultrasonic-assisted extraction (UAE) of phenolic compounds from DLT. According to full factorial design experimental results, total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity, and anti-α-glucosidase activity (α-GIA) of the DLT extracts were simultaneously optimized by response surface methodology. Sonication temperature and water content in ChCl-LevA were found to be the major factors affecting the TPC, TFC, antioxidant activity, and α-GIA of DLT extracts. Under the optimum parameters (water content in ChCl-LevA was 45%, sonication temperature was 50 °C, and extraction time was 30 min), the measured results for all the responses were obtained as follows: TPC-91.38 ± 7.20 mg GAE/g DW, TFC-84.12 ± 3.47 mg RE/g DW, ABTS+-492 ± 7.33 mmol TE/g DW, FRAP-6235 ± 121 μmol Fe(II)/g DW and α-GIA-230 ± 7.59 mmol AE/g DW, which were consistent with the predicted values. In addition, strongly significant positive correlations were observed between TPC/TFC and bio-activities of the DLT extracts. HPLC results indicated high contents of (-)-epigallocatechin (4272 ± 84.86 μg/g DW), catechin (5268 ± 24.53 μg/g DW), isoquercitrin (3500 ± 86.07 μg/g DW), kaempferol 3-O-rutinoside (3717 ± 97.71 μg/g DW), and protocatechuic acid (644 ± 1.65 μg/g DW) were observed in the DLT extracts. In contrast to other extraction methods, ChCl-LevA-based UAE yielded higher TPC, TFC, individual phenolic contents, stronger antioxidant activity, and α-GIA. Scanning electron microscope (SEM) analysis further confirmed that ChCl-LevA-based UAE enhanced the disruption of cell wall structure, thereby making more phenolic antioxidants released from DLT. In short, ChCl-LevA-based UAE was confirmed to be an innovative and high-efficient method for extraction of phenolic antioxidants from DLT. Dogbane leaves can be considered as a good tea source rich in natural antioxidants.

Long non-coding RNAs (lncRNAs) are a new class of regulatory genes that play critical roles in various processes ranging from normal development to human diseases. Recent studies have shown that protein complexes are required for the functions of lncRNAs. The identification of these proteins which are associated with lncRNAs is critical for the understanding of molecular mechanisms of lncRNAs in gene regulation and their functions. In this chapter, we describe a method to isolate proteins associated with lncRNAs. This procedure involves fusion protein Maltose-Binding Protein (MBP) fused to MS2-binding protein to pull down the proteins associated with lncRNA and the identification of these proteins by mass spectrometry.

Many studies have uncovered the essential role of ZBTB7A in regulating tumourigenesis. However, its functional significance in cell responses to endoplasmic reticulum stress (ER stress) remains poorly understood. Here we report that ZBTB7A functions as an important prosurvival factor in osteosarcoma cells undergoing pharmacological ER stress-induced by tunicamycin (TM) or thapsigargin (TG). The downregulation of ZBTB7A expression by ER stress promoted cell apoptosis in vitro and in vivo. ZBTB7A expression levels were increased in osteosarcoma tissues and elevated ZBTB7A was associated with osteosarcoma metastasis. Further mechanistic studies revealed that miR-663a induced by ER stress directly bound to the 3′UTR of ZBTB7A and contributed to ER stress-induced ZBTB7A downregulation in osteosarcoma cells. Additionally, our data revealed that ZBTB7A bound to the promoter of LncRNA GAS5 and transcriptionally suppressed LncRNA GAS5 expression, leading to a decline in ER stress-induced cell apoptosis. Collectively, our findings reveal the prosurvival role of ZBTB7A in osteosarcoma adaptation to ER stress and suggest that the miR-663a-ZBTB7A-LncRNAGAS5 pathway is essential for the survival of human osteosarcoma cells under ER stress.

Background The dismal prognosis of patients with glioma is largely attributed to cancer stem cells that display pivotal roles in tumour initiation, progression, metastasis, resistance to therapy, and relapse. Therefore, understanding how these populations of cells maintain their stem-like properties is critical in developing effective glioma therapeutics. Methods RNA sequencing analysis was used to identify genes potentially involved in regulating glioma stem cells (GSCs). Integrin β4 (ITGB4) expression was validated by quantitative real-time PCR (qRT-PCR) and immunohistochemical (IHC) staining. The role of ITGB4 was investigated by flow cytometry, mammosphere formation, transwell, colony formation, and in vivo tumorigenesis assays. The reciprocal regulation between Integrin β4 and KLF4 was investigated by chromatin immunoprecipitation (ChIP), dual-luciferase reporter assay, immunoprecipitation, and in vivo ubiquitylation assays. Results In this study, we found that ITGB4 expression was increased in GSCs and human glioma tissues. Upregulation of ITGB4 was correlated with glioma grades. Inhibition of ITGB4 in glioma cells decreased the self-renewal abilities of GSCs and suppressed the malignant behaviours of glioma cells in vitro and in vivo. Further mechanistic studies revealed that KLF4, an important transcription factor, directly binds to the promoter of ITGB4, facilitating its transcription and contributing to increased ITGB4 expression in glioma. Interestingly, this increased expression enabled ITGB4 to bind KLF4, thus attenuating its interaction with its E3 ligase, the von Hippel-Lindau (VHL) protein, which subsequently decreases KLF4 ubiquitination and leads to its accumulation. Conclusions Collectively, our data indicate the existence of a positive feedback loop between KLF4 and ITGB4 that promotes GSC self-renewal and gliomagenesis, suggesting that ITGB4 may be a valuable therapeutic target for glioma. Electronic supplementary material The online version of this article (10.1186/s13046-019-1034-1) contains supplementary material, which is available to authorized users.

Arecanut (Areca catechu L.) seed is an important by-product of commercial crop Arecanut planted in tropical or sub-tropical regions. This study for the first time investigated the phyto-chemical compositions and bio-activities of the Arecanut seed extracts extracted by conventional solvents and deep eutectic solvents (DESs). Results showed that the Arecanut seed extracts obtained by the screened DESs exhibited the highest total alkaloid content (TAC, 33.92 mg ARE/g DW), moderate total phenolic content (TPC) and total flavonoid content (TFC). However, high TPC (57.92 mg GAE/g DW) and TFC (427.56 mg RE/g DW) were obtained by acetone and 50 % EtOH, respectively. Ethyl acetate extracts yielded the lowest TPC (0.74 mg GAE/g DW), TFC (4.24 mg RE/g DW) and TAC (0.62 ARE/g DW). A total of 32 compounds (phenolics, flavonoids, and alkaloids) were identified in the Arecanut seed extracts by using high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF/MS) method. Among them, gallic acid, (-)-gallocatechin, (-)-epigallocatechin, D-catechin, isorhamnetin-3-O-galactoside, arecaine, arecoline, and guvacoline were the main compounds. Additionally, two kinds of DESs (L-Proline-Ethylene glycol and L-Proline-Lactic acid) extracts exhibited superior properties on 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS+ ), hydroxyl (OH−) and 2,2-diphenyl-1-picrylhydrazyl (DPPH ) free radical scavenging activities, ferric reducing antioxidant power (FRAP), reducing power, cupric reducing antioxidant capacity (CUPRAC), inhibitory ability of α-glucosidase and anti-bacterial activity as compared with the extracts extracted by other solvents. Multivariate analysis results revealed that the extraction solvents significantly affected the phytochemical constituents and biological activities of the Arecanut seed extracts. In conclusion, Arecanut seed is a potential source enriched in natural antioxidants for application in the medicinal aspects. Additionally, the present work provided eco-friendly DESs for high-efficient extracting the useful active compounds from Arecanut seed.

Herein, high efficient extraction of natural antioxidants from partridge leaf-tea (PLT) was carried out by using eco-friendly choline chloride-based deep eutectic solvents combined with ultrasonic method. Choline chloride-malic acid (ChCl-MaA), a new type of green solvent, with the highest efficient for extracting the natural antioxidants from PLT (DPPH -756.70 ± 12.13 μmol TE/g DW; FRAP-4139.17 ± 65.79 μM Fe(Ⅱ)SE/g DW) was screened for further optimization. The key parameters for simultaneously maximizing total phenolic content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhyldrazyl (DPPH ) and ferric reducing antioxidant activity (FRAP) were optimized by single-factor experiments along with response surface methodology (RSM). Results exhibited that L/S ratio and water content in DES had significant effects on TPC and antioxidant activities, while ultrasonic power indicated a significant negative effect on all responses. Under the optimal conditions (ultrasonic power at 210 W, ultrasonic time at 30 min, L/S ratio at 27.50:1, water content in DES at 45%), experimentally obtained results were obtained as follows: 42.20 ± 2.17 mg GAE/g DW for TPC, 30.33 ± 2.16 mg RE/g DW for TFC, 838.64 ± 12.81 μmol TE/g DW for DPPH , and 5958.33 ± 153.52 μM Fe(Ⅱ)SE/g DW for FRAP, which were well in agreement with the predicted values. Furthermore, ChCl-MaA-based ultrasonic assisted extraction (UAE) yielded higher TPC, TFC and antioxidant activities compared with traditional solvents-based UAE. Strong antioxidant activities of PLT extracts were correlated with high levels of individual antioxidants including salvianic acid A, 3-chlorogenic acid, gallic acid, catechin and rutin. The functional groups analysis by Fourier transform infrared spectroscopy (FT-IR) were used to compare the solvents characterization before and after extraction. Scanning electron microscope (SEM) results further verified ChCl-MaA intensified the destruction of cell wall structure, and thereby allowed greater release of antioxidants from PLT. This work provides an eco-friendly ChCl-MaA-based UAE technique for efficiently extraction and valorization of phenolic compounds from PLT, which can be further used in pharmaceutical, food, and cosmetic industries.

Increasing evidence has revealed the aberrant expression of long non-coding RNAs (lncRNAs) in many cancer types, including oral squamous cell carcinoma (OSCC). However, limited investigations report metastasis-related lncRNAs in OSCC. Herein, we report the identification of dysregulated intergenic lncRNAs in the highly metastatic OSCC cell line, UM-SCC6H. One of the lncRNAs, termed AC132217.4, was remarkably upregulated and promoted cell migration and epithelial-mesenchymal transition (EMT) by upregulating IGF2 expression. Further mechanistic studies revealed that AC132217.4 interacted with the 3′UTR of IGF2 mRNA and increased its stability, leading to increased IGF2 levels. Thereafter, we found that KLF8 binds to the upstream sequence of AC132217.4, activating its expression at the transcriptional level, which accelerated OSCC metastasis via the AC132217.4-IGF2 axis both in vitro and in vivo. We also revealed that the expression level of AC132217.4 was increased in OSCC tissues, and this elevation correlated with KLF8 and IGF2 expression. Thus, our data demonstrate that the KLF8-AC132217.4-IGF2 signalling pathway plays a critical role in OSCC metastasis.

Chemoresistance remains a major drawback to osteosarcoma treatment. ZBTB7A, a member of the POK transcription repressor family, was shown to play an important role in tumorigenesis. However, the effect of ZBTB7A on osteosarcoma chemoresistance is completely unknown. In this study, we found that ZBTB7A is increased in cisplatin-resistant osteosarcoma cells and that elevated ZBTB7A inhibits cisplatin-induced apoptosis by repressing LINC00473 expression. Further mechanistic studies revealed that ZBTB7A directly binds to the promoter and suppresses the transcription of LINC00473. Additionally, our data indicate that LINC00473 interacts with the transcript factor C/EBPβ, facilitating its binding to the promoter of IL24, leading to decrease chemoresistance. Thus, these findings indicate that the ZBTB7A-mediated LINC00473-C/EBPβ-IL24 pathway is a promising novel target for overcoming cisplatin resistance in osteosarcoma.

Background Chemotherapeutic insensitivity remains a big challenge in prostate cancer treatment. Recently, increasing evidence has indicated that KLF4 plays a key role in prostate cancer. However, the potential biological role of KLF4 in Chemotherapeutic insensitivity of prostate cancer is still unknown. Methods The role of KLF4 in cisplatin-induced apoptosis was detected by western blotting and a cell counting kit (CCK8). The potential molecular mechanism of KLF4 in regulating prostate cancer chemosensitivity was investigated by RNA sequencing analysis, q-RT-PCR, western blotting and chromatin immunoprecipitation (ChIP). The expression level of KLF4 mediated by miR-32-5p was confirmed by bioinformatic analysis and luciferase assays. Results Here, we found that KLF4 was induced by cisplatin in prostate cancer cells and that the increase in KLF4 promoted cell apoptosis. Further mechanistic studies revealed that KLF4 directly bound to the promoter of BIK, facilitating its transcription. Additionally, we also found that the gene encoding KLF4 was a direct target of miR-32-5p. The downregulation of miR-32-5p in response to cisplatin treatment promoted KLF4 expression, which resulted in a increase in the chemosensitivity of prostate cancer. Conclusion Thus, our data revealed that KLF4 is an essential regulator in cisplatin-induced apoptosis, and the miR-32-5p-KLF4-BIK signalling axis plays an important role in prostate cancer chemosensitivity. Electronic supplementary material The online version of this article (10.1186/s12964-018-0270-x) contains supplementary material, which is available to authorized users.

Background Adaptation to ER stress has been indicated to play an important role in resistance to therapy in human melanoma. However, the relationship between adaptation to ER stress and cell metastasis in human melanoma remains unclear. Methods The relationship of adaptation to ER stress and cell metastasis was investigated using transwell and mouse metastasis assays. The potential molecular mechanism of KLF4 in regulating the adaptation to ER stress and cell metastasis was investigated using RNA sequencing analysis, q-RT-PCR and western blot assays. The transcriptional regulation of nucleobindin 2 (NUCB2) by KLF4 was identified using bioinformatic analysis, luciferase assay, and chromatin immunoprecipitation (ChIP). The clinical significance of KLF4 and NUCB2 was based on human tissue microarray (TMA) analysis. Results Here, we demonstrated that KLF4 was induced by ER stress in melanoma cells, and increased KLF4 inhibited cell apoptosis and promoted cell metastasis. Further mechanistic studies revealed that KLF4 directly bound to the promoter of NUCB2, facilitating its transcription. Additionally, an increase in KLF4 promoted melanoma ER stress resistance, tumour growth and cell metastasis by regulating NCUB2 expression in vitro and in vivo. Elevated KLF4 was found in human melanoma tissues, which was associated with NUCB2 expression. Conclusion Our data revealed that the promotion of ER stress resistance via the KLF4-NUCB2 axis is essential for melanoma cell metastasis, and KLF4 may be a promising specific target for melanoma therapy.

Background The tumour microenvironment is essential for cancer progress and metastasis. Integrin-β5 (ITGB5), a member of the integrin family, has been implicated to mediate the interactions of cells with the extracellular matrix (ECM) and promote tumorigenesis in several malignancies. However, the role of ITGB5 in hepatocellular carcinoma (HCC) is still unknown. Methods The biological function of ITGB5 in HCC was investigated using migration, colony formation assays. The potential molecular mechanism of ITGB5 in regulating HCC tumorigenesis and β-catenin stabilization was investigated by western blotting, co-immunoprecipitation and ubiquitination assays. The expression level of ITGB5 mediated by miR-185 was confirmed by bioinformatic analysis, luciferase assay. The clinical significance of ITGB5 was based on human tissue microarray (TMA) analysis. Results Here, we found that the expression of ITGB5 is increased in HCC tissues. Elevated ITGB5 markedly facilitates HCC cell migration and tumorigenesis in vitro and in vivo. Further mechanistic studies revealed that ITGB5, as a partner of β-catenin, directly interacts with β-catenin and inhibits its degradation, thus leading to WNT/β-catenin activity. Subsequently, we also found that ITGB5 is a direct targeted gene of miR-185. The downregulation of miR-185 in HCC cells promotes an increase in ITGB5. An additional increase of ITGB5 is associated with β-catenin upregulation and a miR-185 decrease in HCC tissues. Conclusions Our data reveal that the miR-185-ITGB5-β-catenin pathway plays an important role in HCC tumorigenesis, and ITGB5 may be a promising specific target for HCC therapy. Electronic supplementary material The online version of this article (10.1186/s13046-018-0691-9) contains supplementary material, which is available to authorized users.