Purine and purinergic receptors in health and disease.

Purines and purinergic receptors are widely distributed throughout the human body. Purine molecules within cells play crucial roles in regulating energy metabolism and other cellular processes, while extracellular purines transmit signals through specific purinergic receptors. The ubiquitous purinergic signaling maintains normal neural excitability, digestion and absorption, respiratory movement, and other complex physiological activities, and participates in cell proliferation, differentiation, migration, and death. Pathological dysregulation of purinergic signaling can result in the development of various diseases, including neurodegeneration, inflammatory reactions, and malignant tumors. The dysregulation or dysfunction of purines and purinergic receptors has been demonstrated to be closely associated with tumor progression. Compared with other subtypes of purinergic receptors, the P2X7 receptor (P2X7R) exhibits distinct characteristics (i.e., a low affinity for ATP, dual functionality upon activation, the mediation of ion channels, and nonselective pores formation) and is considered a promising target for antitumor therapy, particularly in patients with poor response to immunotherapy This review summarizes the physiological and pathological significance of purinergic signaling and purinergic receptors, analyzes their complex relationship with tumors, and proposes potential antitumor immunotherapy strategies from tumor P2X7R inhibition, tumor P2X7R overactivation, and host P2X7R activation. This review provides a reference for clinical immunotherapy and mechanism investigation.

Tanshinone I attenuates gastric precancerous lesions by inhibiting epithelial mesenchymal transition through the p38/STAT3 pathway.

BACKGROUND: Gastric precancerous lesions (GPLs) are omens for gastric cancer (GC), which developing with a series of pathological changes of gastric mucosa. Reversing epithelial-mesenchymal transition (EMT) in gastric mucosa is the main approach to restrain GPLs from evolving into cancer. Tanshinone I (Tan-I), the active ingredients of traditional Chinese herb Salvia miltiorrhiza, has exhibited anticancer effect. PURPOSE: To investigate the effect and mechanism of Tan-I in intervening GPLs, and provide a new therapeutic strategy for prevention of GC. METHODS: Gastric mucosal epithelial cells were treated with the N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) to construct MNNG-induced cell (MC cell) of gastric mucosa that undergoing EMT process. Then, this study explored the effect and mechanism of Tan-I in vitro. Subsequently, this study constructed GPL mice to clarify the exact efficacy and mechanism of Tan-I on GPLs. RESULTS: Tan-I inhibited MC cell proliferation, invasion and migration. Simultaneously, the aberrant expression of E-cadherin and N-cadherin were reversed. Tan-I attenuated inflammation by reducing the release of nitric oxide, TNFα and IL-1ß. Tan-I reversed the EMT and inflammatory processes by regulating p38 and STAT3. CONCLUSION: This study showed that Tan-I inhibited the progression of GPLs by reversing the EMT process and reducing inflammation by restraining the p38/STAT3 signaling pathway.

Targeting extracellular matrix through phytochemicals: a promising approach of multi-step actions on the treatment and prevention of cancer.

Extracellular matrix (ECM) plays a pivotal and dynamic role in the construction of tumor microenvironment (TME), becoming the focus in cancer research and treatment. Multiple cell signaling in ECM remodeling contribute to uncontrolled proliferation, metastasis, immune evasion and drug resistance of cancer. Targeting trilogy of ECM remodeling could be a new strategy during the early-, middle-, advanced-stages of cancer and overcoming drug resistance. Currently nearly 60% of the alternative anticancer drugs are derived from natural products or active ingredients or structural analogs isolated from plants. According to the characteristics of ECM, this manuscript proposes three phases of whole-process management of cancer, including prevention of cancer development in the early stage of cancer (Phase I); prevent the metastasis of tumor in the middle stage of cancer (Phase II); provide a novel method in the use of immunotherapy for advanced cancer (Phase III), and present novel insights on the contribution of natural products use as innovative strategies to exert anticancer effects by targeting components in ECM. Herein, we focus on trilogy of ECM remodeling and the interaction among ECM, cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs), and sort out the intervention effects of natural products on the ECM and related targets in the tumor progression, provide a reference for the development of new drugs against tumor metastasis and recurrence.

Chelerythrine chloride inhibits the progression of colorectal cancer by targeting cancer-associated fibroblasts through intervention with WNT10B/ß-catenin and TGFß2/Smad2/3 axis.

Chelerythrine chloride (CHE) is a benzodiazepine alkaloid derived from natural herbs with significant anti-tumor and anti-inflammatory activities. However, the exact role and underlying mechanisms of CHE in colorectal cancer (CRC) remain unclear. Therefore, this study is aimed to investigate the influence of CHE on the progression of CRC. Cell Counting Kit-8 assay (CCK-8), transwell, apoptosis rate, cell cycle distribution, reactive oxygen species (ROS), and colony formation determined the anti-proliferative activity of CHE in CRC cell lines. Transcriptome sequencing and western blot were used to explore the mechanism. Finally, H&E staining, Ki67, TUNEL, and immunofluorescence were conducted to verify the anti-CRC activity and potential mechanisms of CHE in vivo. CHE had a prominent inhibitory effect on the proliferation of CRC cells. CHE induces G1 and S phase arrest and induces cell apoptosis by ROS accumulation. Cancer-associated fibroblasts (CAFs) play a key role in CRC metastasis. Then, this study found that CHE regulates WNT10B/ß-catenin and TGFß2/Smad2/3 axis, thereby decreasing the expression of α-SMA, which is a maker of CAFs. Taken together, CHE is a candidate drug and a potent compound for metastatic CRC, which can intervene CAFs in a dual pathway to effectively inhibit the invasion and migration of cancer cells, which can provide a new choice for future clinical treatment.

Renoprotective Effects of Tanshinone IIA: A Literature Review.

The kidney is an important organ in the human body, with functions such as urine production, the excretion of metabolic waste, the regulation of water, electrolyte and acid-base balance and endocrine release. The morbidity and mortality of kidney diseases are increasing year by year worldwide, and they have become a serious public health problem. In recent years, natural products derived from fungi, plants and animals have become an important alternative source of treatment for kidney diseases because of their multiple pathways, multiple targets, safety, low toxicity and few side effects. Tanshinone IIA (Tan IIA) is a lipid-soluble diterpene quinone isolated from the Chinese herb Salvia miltiorrhiza, considered as a common drug for the treatment of cardiovascular diseases. As researchers around the world continue to explore its unknown biological activities, it has also been found to have a wide range of biological effects, such as anti-cancer, anti-oxidative stress, anti-inflammatory, anti-fibrotic, and hepatoprotective effects, among others. In recent years, many studies have elaborated on its renoprotective effects in various renal diseases, including diabetic nephropathy (DN), renal fibrosis (RF), uric acid nephropathy (UAN), renal cell carcinoma (RCC) and drug-induced kidney injury caused by cisplatin, vancomycin and acetaminophen (APAP). These effects imply that Tan IIA may be a promising drug to use against renal diseases. This article provides a comprehensive review of the pharmacological mechanisms of Tan IIA in the treatment of various renal diseases, and it provides some references for further research and clinical application of Tan IIA in renal diseases.

Direct adsorption sampling and ambient mass spectrometry analysis of tobacco smoke with porous paper strips.

Chemical analysis of atmospheric aerosols by conventional analytical methods is usually required to perform complicated and time-consuming sample preparation processes. In recent decades, ambient ionization mass spectrometry (AI-MS) methods have been proven to be simple, rapid, and effective analytical tools for direct analysis of various complex samples. In this work, we applied porous paper filters for direct adsorptive sampling of tobacco smoke, and then the sampled paper filters were performed the emitters of the paper spray ionization (PSI) device. An auto-sampling device was made to control the generation and collection of tobacco smoke. Nicotine, the typical compound of tobacco smoke, was used to optimize the key conditions of auto-sampling. Moreover, different types of tobacco smoke were also compared with multivariate variable analysis, and the makers of tobacco smoke from different sources of tobacco smoke were investigated. By using this method, direct sampling and analysis of a single tobacco sample can be completed within minutes. Overall, our results show that PSI-MS is a powerful tool that integrates collection, extraction, ionization, and identification analytes in smoke.

Determination and Difference Analysis of Phenolic Compounds in Smokers' Saliva and Mainstream Smoke.

To study the differences in phenolic compounds between tobacco smokers' saliva and mainstream smoke, a method was developed for the analysis of 12 phenolic compounds in saliva and mainstream smoke based on ultrahigh-performance liquid chromatography with fluorescence detection (UPLC-FLD). The contents and distributions of phenolic compounds in tobacco smokers' saliva and mainstream smoke were compared. The results were as follows: (1) Phenolic compounds were quantitatively analyzed by the internal standard method using 4-fluorophenol as an internal standard. For smokers' saliva samples, the limits of quantification (LOQs) ranged from 2.2 to 19.1 µg/L, and the recoveries were from 80.2% to 119.2% at the three spiked levels. For mainstream smoke samples, the LOQs ranged from 0.03 to 0.26 µg/cig, and the recoveries ranged from 84.9% to 107.0% at the three spiked levels. (2) The contents of phenolic compounds from 14 cigarettes in mainstream smoke and smokers' saliva were determined. In mainstream smoking, the main phenolic compounds were hydroquinone, catechol, phenol, meta- and para-Cresol, and o-methylhydroquinone. In smokers' saliva, the main phenolic compounds were phenol and meta- and para-Cresol and the contents of phenolic compounds in smokers' saliva from different cigarettes were significantly different. (3) The content distribution patterns of phenolic compounds in smokers' saliva differed from those in mainstream smoke. The predominant phenolic compound in mainstream smoke was dihydroxybenzene, while monophenols predominated in smokers' saliva. (4) The contents of phenolic compounds from five kinds of cigarettes were analyzed in the saliva of different smokers using principal component analysis, which indicated that cigarettes with different sensory effects were clearly distinguished by differences in the contents of phenolic compounds in saliva.

METTL3 inhibits inflammation of retinal pigment epithelium cells by regulating NR2F1 in an m6A-dependent manner.

N6-metyladenosine (m6A) RNA methylation has been proven to be involved in diverse biological processes, but its potential roles in the development of lipopolysaccharide (LPS) induced retinal pigment epithelium (RPE) inflammation have not been revealed. In this study, we explored the effects and underlying mechanisms of methyltransferase-like 3 (METTL3) in LPS stimulated RPE cells. Proliferation of METTL3-silenced RPE cells was examined by Cell counting kit-8 (CCK8) and 5-Ethynyl-2´-Deoxyuridine (Edu). Expression of tight junction proteins ZO-1 and Occludin, and secretion of inflammatory factors interleukins (IL)-1, 6 and 8 were detected by Western blotting or Enzyme-linked immunosorbent assay (ELISA). RNA sequencing and methylated RNA immunoprecipitation (MeRIP) sequencing were used to analyze the target gene nuclear receptor subfamily 2 group F member 1 (NR2F1) of METTL3. Our results showed that both human RPE (hRPE) cells and ARPE19 cells exhibited inhibited proliferation, tight junction protein expression, and increased inflammatory factor secretion after METTL3 silencing. Mechanistically, we found that NR2F1, as a METTL3-methylated target gene, inhibits Occludin level and promotes IL-6 secretion of RPE cells in an m6A-dependent manner. Interestingly, NR2F1 deficiency reversed the decreased Occludin expression and increased IL-6 secretion in METTL3-defective RPE cells. In conclusion, our study revealed that METTL3 attenuates RPE cell inflammation by methylating NR2F1, suggesting the critical role of METTL3 in RPE cells.

N6-methyladenosine demethylase FTO regulates inflammatory cytokine secretion and tight junctions in retinal pigment epithelium cells.

OBJECTIVE: Uveitis is an intraocular inflammatory disease. Epigenetics has been associated with its pathogenesis. However, the role of N6-methyladenosine (m6A) in uveitis has not been reported. We aimed to examine the role of m6A and its regulatory mechanism in experimental autoimmune uveitis (EAU). METHODS: The mRNA expression of m6A-related methylase and demethylase of retinal pigment epithelium (RPE) between mice with EAU and control mice was detected by RT-qPCR. The overall m6A level of ARPE-19 cells was detected by an m6A quantitative detection kit. Cell proliferation was observed by CCK-8 assays, and ELISA was used to test the secretion of inflammatory factors. The expression of tight junction proteins and the target genes of FTO were examined by western blotting and MeRIP-PCR. RESULTS: A decreased expression of FTO in RPE cells was found in mice with EAU. Increased overall m6A%, proliferation of cells and secretion of IL-6, IL-8 and MCP-1 were found after FTO knockdown in ARPE-19 cells. However, ZO-1 and occludin protein expression was decreased. ATF4 protein expression was decreased in the FTO knockdown (shFTO) group as compared with the control (shNC) group. In contrast, the m6A level of ATF4 was elevated, as shown by MeRIP-PCR. Functional analysis showed that p-STAT3 expression was increased in the shFTO group, and the change in occludin expression was reversed in ATF4 rescue experiment. CONCLUSION: FTO may affect the translation of ATF4 by regulating its m6A level, resulting in the increased expression of p-STAT3 and inflammatory factors, and leading to uveitis.

Three new sesquiterpenes from the stems of Nicotiana tabacum and their bioactivities.

Three new sesquiterpenes, methyl 4-isopropyl-7-methoxy-6-methylnaphthalene-1-carboxylate (1), methyl 2-hydroxy-4-isopropyl-7-methoxy-6-methylnaphthalene-1-carboxylate (2), and methyl 2-hydroxy-6-(hydroxymethyl)-4-isopropyl-7-methoxynaphthalene-1-carboxylate (3), together with three known sesquiterpenes (4-6), were isolated from the stems of Nicotiana tabacum. Their structures were determined by means of HRESIMS and extensive 1D and 2D NMR spectroscopic studies. The results showed that compounds 2, 3, and 5 exhibited high anti-TMV activity with inhibition rates of 33.6, 35.8, and 36.7%. Compounds 1-6 showed weak inhibitory activities against some tested human tumor cell lines (NB4, A549, SHSY5Y, PC3, and MCF7) with IC50 values in the range of 6.7-9.6 µM.

Rab-like protein 1 A is upregulated by cisplatin treatment and partially inhibits chemoresistance by regulating p53 activity.

Rab-like protein 1 A (RBEL1A), which is a predominant isoform of RBEL1, has been identified to serve an important function in breast tumorigenesis and may be upregulated in breast tumor cells. RBEL1A may block the transcriptional activity of p53, which is important in the induction of cisplatin sensitivity. Previous studies supported the association between the induction of chemoresistance and the inhibition of p53 by RBEL1A. However, the response of RBEL1A to chemotreatment and its interaction with p53 remains to be investigated. The present study revealed that the cisplatin treatment induced the expression of RBEL1A in MCF-7 cells. Consistent with previous studies, the present study demonstrated that cisplatin treatment and RBEL1A overexpression blocked the oligomerization of p53 in MCF-7 cells and led to a decrease of the transcriptional activity of p53 and its downstream target gene p21. Additionally, upregulation of RBEL1A decreased the protein level of p53 by promoting the ubiquitination of p53. A cytotoxicity assay demonstrated that upregulation of RBEL1A partially contributed to chemosensitivity via inhibiting p53 in MCF-7 cells. A pG13L (p53-responsive reporter plasmid) luciferase reporter and co-immunoprecipitation assay revealed that upregulation of RBEL1A led to an inhibition of the transcriptional activity of p53 or its target gene p21. Analysis of cellular proliferation, cell cycle and invasion also confirmed the regulatory activity of RBEL1A on the malignancy of breast cancer cells. Taken together, these results suggest that the induction of RBEL1A following cisplatin treatment may partially inhibit chemosensitivity in a p53-dependent manner.

Isopentylated diphenyl ether derivatives from the fermentation products of an endophytic fungus Phomopsis fukushii.

Three new isopentylated diphenyl ethers, (1-3), together with two known isopentylated diphenyl ethers derivatives (4 and 5) were isolated from the fermentation products of an endophytic fungus Phomopsis fukushii. Their structures were elucidated by spectroscopic methods, including extensive 1D- and 2D NMR techniques. Compounds 1-3 were evaluated for their anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) activity. The results showed that compounds 1-3 showed strong activity with diameter of inhibition zone (IZD) of 21.8 ± 2.4 mm, 16.8 ± 2.2 mm, and 15.6 ± 2.0 mm, respectively.

Three new isoflavones from the Pueraria montana var. lobata (Willd.) and their bioactivities.

Three new isoflavones, 7-acetyl-4',6-dimethoxy-isoflavone (1), 7-acetyl-4'-hydroxy-6-methoxy-isoflavone (2) and 7-acetyl-6,8-dimethoxy-4'-hydroxy-isoflavone (3), together with five known flavones (4-8), were isolated from the Pueraria montana var. lobata (Willd.). Their structures were elucidated by spectroscopic methods, including extensive 1D- and 2D NMR techniques. Compounds 1-8 were evaluated for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compounds 1 and 2 exhibited high anti-TMV activities with inhibition rates of 36.8 and 33.6%, respectively. The inhibition rates are higher than that of positive control. The other compounds also showed potential anti-TMV activities with inhibition rates in the range of 21.8~28.4%, respectively. The cytotoxicities of compounds 1-3 against five human tumour cell lines (NB4, A549, SHSY5Y, PC3 and MCF7) were also tested. The results revealed that compounds 1-3 showed weak inhibitory activities against some tested human tumour cell lines with IC50 values in the range of 1.2-3.6 µM.

Three new isobenzofurans from the roots of Nicotiana Tabacum and their bioactivities.

Three new isobenzofurans (1-3), together with four known phenylpropanoids (4-7) were isolated from the roots of Nicotiana tabacum. Their structures were determined by means of HRESIMS and extensive 1D and 2D NMR spectroscopic studies. Compounds 1-6 were tested for their anti-tobacco mosaic virus (anti-TMV) activities and cytotoxicity activities. The results showed that compounds 5 and 6 exhibited high anti-TMV activities with inhibition rates of 35.1 and 33.4%, respectively. The cytotoxicities of compounds 1-7 against five human tumor cell lines (NB4, A549, SHSY5Y, PC3 were also tested. Compounds 1-7 showed weak inhibitory activities against some tested human tumor cell lines with IC50 values in the range of 3.8-9.6 µM.

Three new benzolactones from Lavandula angustifolia and their bioactivities.

Three new benzolactones (1-3), together with four known ones (4-7), were isolated from the whole herb of Lavandula angustifolia. Their structures were established on the basis of detailed spectroscopic analysis (1D- and 2D-NMR, HRESIMS, UV, and IR) and comparison with data reported in the literature. New compounds were evaluated for their anti-tobacco mosaic virus (TMV) activities and cytotoxic activities. The results revealed that compounds 1-3 showed obvious anti-TMV activities with inhibition rates of 26.9, 30.2, and 28.4%, which were at the same grade as positive control. Compounds 1-3 also showed weak inhibitory activities against some tested human tumor cell lines with IC50 values in the range of 32.1-7.6 µM.

Three new phenylpropanoids from Lavandula angustifolia and their bioactivities.

Three new phenylpropanoids, 3-(3,4-dimethoxy-5-methylphenyl)-3-oxopropyl acetate (1), 3-hydroxy-1-(3,4-dimethoxy-5-methylphenyl)propan-1-one (2), and 3-hydroxy-1-(4-methylbenzo[d][1,3]dioxol-6-yl) propan-1-one (3), together with three known phenylpropanoids (4-6) were isolated from the whole plant of Lavandula angustifolia. Their structures were determined by means of HRESIMS and extensive 1D and 2D NMR spectroscopic studies. Compounds 1-6 were tested for their anti-tobacoo mosaic virus (TMV) activities and cytotoxicity activities. The results revealed that compounds 1-3 showed high anti-TMV activity with inhibition rate of 35.2, 38.4 and 33.9%. These rates are higher than that of positive control. The other compounds also showed potential anti-TMV activities with inhibition rates in the range of 26.8-28.9%, respectively. Compounds 1-6 also showed weak inhibitory activities against some tested human tumour cell lines with IC50 values in the range of 3.8-8.8 µM.

Cyclic-AMP-dependent protein kinase (PKA) activity assay based on FRET between cationic conjugated polymer and chromophore-labeled peptide.

A sensitive fluorescence turn-on biosensing platform for protein kinase activity assay has been developed based on fluorescence resonance energy transfer (FRET) between a fluorophore labeled peptide and a water soluble cationic conjugated polymer (CCP). The CCP-based assay is based on the electrostatic interaction between the peptide and the CCP. The FRET efficiency will change with the changing charges around the peptide after phosphorylation. The feasibility of this method has been demonstrated by sensitive measurement of the activity of cAMP-dependent protein kinase (PKA) with a low detection limit (0.3 mU µL(-1)). Based on its simple mechanism, this assay is also sensitive and robust enough to be applied to the evaluation of PKA inhibitor H-89. The IC50 value, the half maximal inhibitory concentration, was 40 nM. Furthermore, our method has excellent selectivity. CCP-based assay is sensitive, versatile, cost-effective and easy to operate, so, this method is a promising candidate for kinase activity assay and inhibitor screening.