Ursolic acid inhibits cigarette smoke extract-induced human bronchial epithelial cell injury and prevents development of lung cancer

Exploring the Potential Use of Natural Products Together with Alkalization in Cancer Therapy

Cancer treatment is a significant focus in medicine, owing to the increasing global incidence of cancers. Patients with advanced cancers that do not respond to conventional therapies have limited options and an unfavorable prognosis. Consequently, researchers are investigating complementary approaches to conventional treatments. One such approach is alkalization therapy, which aims to neutralize the acidic tumor microenvironment (TME) by increasing its pH level. The acidic TME promotes inflammation, tumor progression, and drug resistance. Alkalization therapy has been demonstrated to be effective for various cancers. In addition, natural products, such as triterpenoids, parthenolides, fulvic acid, Taxus yunnanensis, and apple pectin have the potential to alleviate symptoms, maintain physical fitness, and improve treatment outcomes of cancer patients through their anti-inflammatory, antioxidant, and anticancer properties. In this review, we focus on the effects of alkalization therapy and natural products on cancer. Furthermore, we present a case series of advanced cancer patients who received alkalization therapy and natural products alongside standard treatments, resulting in long-term survival. We posit that alkalization therapy together with supplementation with natural products may confer benefits to cancer patients, by mitigating the side effects of chemotherapy and complementing standard treatments. However, further research is warranted to validate these clinical findings.

Overexpressed RBPMS-AS1 increased cell radiosensitivity by sponging miR-19a-3p in lung cancer cell lines (A549 and SK-MES-1) via regulating PTEN/AKT axis

PURPOSE

This paper intended to study RBPMS-AS1 in lung cancer (LC) radiosensitivity.

MATERIALS AND METHODS

LC cells were transfected with RBPMS-AS1 overexpression plasmid and miR-19a-3p mimic and treated with radiation. PTEN, AKT, p-AKT, RBPMS-AS1, and miR-19a-3p expressions were detected via Western blot and qRT-PCR. The localization of RBPMS-AS1 in cells was determined through fluorescence in situ hybridization assay. The targeting relationships of RBPMS-AS1 and miR-19a-3p/miR-19a-3p and PTEN were determined through RIP and dual luciferase reporter analysis. Cell survival, viability, and apoptosis were assessed through colony formation, CCK-8, and flow-cytometry assays.

RESULTS

RBPMS-AS1 was downregulated in LC and mainly distributed in cytoplasm. RBPMS-AS1 targeted miR-19a-3p in LC cells. Radiation suppressed LC cell survival, viability, and induced apoptosis, as overexpressed RBPMS-AS1 performed the similar effects and enhanced those effects induced by radiation. MiR-19a-3p mimic reversed the effect of overexpressed RBPMS-AS1 on enhancing radiation-induced LC cell apoptosis. MiR-19a-3p targeted PTEN and miR-19a-3p mimic reversed the effect of overexpressed RBPMS-AS1 on PTEN and phosphorylation of AKT in LC cells.

CONCLUSION

Overexpressed RBPMS-AS1 sponged miR-19a-3p to increase cell radiosensitivity in LC via regulating PTEN/AKT axis.

Inhibitory Effect and Mechanism of Ursolic Acid on Cisplatin-Induced Resistance and Stemness in Human Lung Cancer A549 Cells

The survival rate of lung cancer patients remains low largely due to chemotherapy resistance during treatment, and cancer stem cells (CSCs) may hold the key to targeting this resistance. Cisplatin is a chemotherapy drug commonly used in cancer treatment, yet the mechanisms of intrinsic cisplatin resistance have not yet been determined because lung CSCs are hard to identify. In this paper, we proposed a mechanism relating to the function of ursolic acid (UA), a new drug, in reversing the cisplatin resistance of lung cancer cells regulated by CSCs. Human lung cancer cell line A549 was selected as the model cell and treated to become a cisplatin-resistant lung cancer cell line (A549-CisR), which was less sensitive to cisplatin and showed an enhanced capability of tumor sphere formation. Furthermore, in the A549-CisR cell line expression, levels of pluripotent stem cell transcription factors Oct-4, Sox-2, and c-Myc were increased, and activation of the Jak2/Stat3 signaling pathway was promoted. When UA was applied to the cisplatin-resistant cells, levels of the pluripotent stem cell transcription factors were restrained by the inhibition of the Jak2/Stat3 signaling pathway, which reduced the enrichment of tumor stem cells, and in turn, reversed cisplatin resistance in lung cancer cells. Hence, as a potential antitumor drug, UA may be able to inhibit the enrichment of the lung CSC population by inhibiting the activation of the Jak2-Stat3 pathway and preventing the resistance of lung cancer cells to cisplatin.

Effects of rosmarinic acid, carnosic acid, rosmanol, carnosol, and ursolic acid on the pathogenesis of respiratory diseases

This review aimed to identify preclinical and clinical studies examining the effects of rosmarinic acid (RA), carnosic acid (CaA), rosmanol (RO), carnosol (CA), and ursolic acid (UA) against allergic and immunologic disorders. Various online databases, including PubMed, Science Direct, EMBASE, Web of Sciences, Cochrane trials, and Scopus, were searched from inception until October 2022. Due to the suppression of the nuclear factor-κB (NF-κB) pathway, the main factor in allergic asthma, RA may be a promising candidate for the treatment of asthma. The other ingredients comprising CA and UA reduce the expression of interleukin (IL)-4, IL-5, and IL-13 and improve airway inflammation. Rosemary's anti-cancer effect is mediated by several mechanisms, including DNA fragmentation, apoptosis induction, inhibition of astrocyte-upregulated gene-1 expression, and obstruction of cell cycle progression in the G1 phase. The compounds, essentially found in Rosemary essential oil, prevent smooth muscle contraction through its calcium antagonistic effects, inhibiting acetylcholine (ACH), histamine, and norepinephrine stimulation. Additionally, CA exhibits a substantially greater interaction with the nicotinic ACH receptor than a family of medications that relax the smooth muscles, making it a potent antispasmodic treatment. The components have demonstrated therapeutic effects on the immune, allergy, and respiratory disorders.

Evidence of the Beneficial Effects of Ursolic Acid against Lung Cancer

Lung cancer is the leading cause of cancer-related deaths globally. Despite current treatment approaches that include surgery, chemotherapy, radiation and immunotherapies, lung cancer accounted for 1.79 million deaths worldwide in 2020, emphasizing the urgent need to find novel agents and approaches for more effective treatment. Traditionally, chemicals derived from plants, such as paclitaxel and docetaxel, have been used in cancer treatment, and in recent years, research has focused on finding other plant-derived chemicals that can be used in the fight against lung cancer. Ursolic acid is a polyphenol found in high concentrations in cranberries and other fruits and has been demonstrated to have anti-inflammatory, antioxidant and anticancer properties. In this review, we summarize recent research examining the effects of ursolic acid and its derivatives on lung cancer. Data from in vitro cell culture and in vivo animal studies show potent anticancer effects of ursolic acid and indicate the need for clinical studies.

Potential Natural Small Molecular Compounds for the Treatment of Chronic Obstructive Pulmonary Disease: An Overview

Chronic obstructive pulmonary disease (COPD) is one of the major diseases threatening human life and health. According to the report released by the World Health Organization (WHO) in 2020, COPD has become the third leading cause of death in the world, featuring a sustainable growth of incidence rate as well as population age. The purpose of this review focuses on the advancement of bioactive natural compounds, such as baicalin, quercetin, resveratrol, and curcumin, which demonstrate promising therapeutic/interventional effects on CODP in vitro and in vivo. Information emphasizing on COPD was systematically collected from several authoritative internet databases including Web of Science, PubMed, Elsevier, Wiley Online Library, and Europe PMC, with a combination of keywords containing “COPD” and “natural small molecular compounds”. The new evidence indicated that these valuable molecules featured unique functions in the treatment of COPD through various biological processes such as anti-inflammatory, anti-oxidant, anti-apoptosis, and anti-airway fibrosis. Moreover, we found that the promising effects of these natural compounds on COPD were mainly achieved through JAK3/STAT3/NF-κB and MAPK inflammatory signaling pathways, Nrf2 oxidative stress signaling pathway, and TGF-β1/Smad 2/3 fibrosis signaling pathway, which referenced to multiple targets like TNF-α, IL-6, IL-8, TIMP-1, MMP, AKT, JAK3, IKK, PI3K, HO-1, MAPK, P38, ERK, etc. Current challenges and future directions in this promising field are also discussed at the end of this review. For the convenience of the readers, this review is divided into ten parts according to the structures of potential natural small molecular compounds. We hope that this review brings a quick look and provides some inspiration for the research of COPD.

MiR-552-3p facilitated cell proliferation, migration and invasion by sponging Fibulin 5 in non-small cell lung cancer via activation of ERK/GSK3β/β-catenin signaling pathway

Apart from the fact that miR-552-3p is known to promote cell progression among various cancers, its function on non-small cell lung cancer (NSCLC) is unknown which therefore emerges as the purpose of this research. TargetScan, Starbase, miRWalk, miRDB and the Cancer Genome Atlas Lung Adenocarcinoma (TCGA-LUAD) were utilized to analyze the target genes of miR-552-3p. NSCLC cells were transfected with miR-552-3p mimic, miR-552-3p inhibitor, Fibulin 5 (FBLN5) overexpression plasmid, and small interfering FBLN5 (siFBLN5) and treated with extracellular regulated protein kinases (ERK) pathway inhibitor PD98059. MiR-552-3p, FBLN5, p-ERK, ERK, p-glycogen synthase kinase 3β (GSK3β) and β-catenin levels were detected through quantitative reverse transcription-polymerase chain reaction and western blot. The binding sites between miR-552-3p and FBLN5 were predicted by TargetScan, which was tested through dual luciferase reporter analysis. Cell viability, migration and invasion were determined by cell counting kit-8 (CCK-8) assay, wound healing assay and transwell assay, respectively. MiR-552-3p expression was upregulated in NSCLC and FBLN5 functioned as its target. MiR-552-3p mimic promoted proliferation, migration, invasion, p-ERK, p-GSK3β and β-catenin expressions in NSCLC cells while miR-552-3p inhibitor did the opposite. Overexpressed FBLN5 suppressed proliferation, migration, invasion, p-ERK, p-GSK3β and β-catenin expressions in NSCLC cells whereas siFBLN5 exerted the effects opposite to overexpressed FBLN5. PD98059 enhanced the effect of overexpressed FBLN5 on NSCLC cell migration and invasion while reversing the effect of siFBLN5. MiR-552-3p facilitated cell proliferation, migration and invasion in NSCLC through sponging FBLN5 via activation of ERK/GSK3β/β-catenin pathway.

Cancer Chemopreventive Role of Dietary Terpenoids by Modulating Keap1-Nrf2-ARE Signaling System—A Comprehensive Update

ROS, RNS, and carcinogenic metabolites generate excessive oxidative stress, which changes the basal cellular status and leads to epigenetic modification, genomic instability, and initiation of cancer. Epigenetic modification may inhibit tumor-suppressor genes and activate oncogenes, enabling cells to have cancer promoting properties. The nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that in humans is encoded by the NFE2L2 gene, and is activated in response to cellular stress. It can regulate redox homoeostasis by expressing several cytoprotective enzymes, including NADPH quinine oxidoreductase, heme oxygenase-1, UDP-glucuronosyltransferase, glutathione peroxidase, glutathione-S-transferase, etc. There is accumulating evidence supporting the idea that dietary nutraceuticals derived from commonly used fruits, vegetables, and spices have the ability to produce cancer chemopreventive activity by inducing Nrf2-mediated detoxifying enzymes. In this review, we discuss the importance of these nutraceuticals in cancer chemoprevention and summarize the role of dietary terpenoids in this respect. This approach was taken to accumulate the mechanistic function of these terpenoids to develop a comprehensive understanding of their direct and indirect roles in modulating the Keap1-Nrf2-ARE signaling system.

LINC01272 Suppressed Cell Multiplication and Induced Apoptosis Via Regulating MiR-7-5p/CRLS1 Axis in Lung Cancer

LINC01272 is a long non-coding RNA (lncRNA) that has been considered as a biomarker for many diseases including lung squamous cell carcinoma. Here, we investigated the function and mechanism of LINC01272 on lung cancer (LC). The differential expression of LINC01272 in LC and normal samples was analyzed by GEPIA based on the data from TCGA-LUAD database, as survival prognosis was analyzed through Kaplan-Meier Plotter. LINC01272 overexpression plasmid and miR-7-5p mimic were transfected into A549 and PC-9 cells. LINC01272, miR-7-5p and cardiolipin synthase 1 (CRLS1) mRNA expression was measured by quantitative reverse transcription-polymerase chain reaction. Cell viability was detected through MTT assay. Cell multiplication was evaluated by cell formation assay. Cell apoptosis was assessed through flow cytometry assay. Through bioinformatics, the target miRNA of LINC01272 and downstream genes of miR-7-5p were predicted. The targeting relationship was tested by dual luciferase reporter analysis. CRLS1, B-cell lymphoma-2 (Bcl-2), BCL2-associated X (Bax) and cleaved caspase-3 protein levels were detected through western blot. LINC01272 was downregulated in LC and low LINC01272 expression had poor prognosis. In A549 and PC-9 cells, LINC01272 inhibited cell viability and multiplication and induced apoptosis. LINC01272 negatively regulated miR-7-5p and CRLS1 was a target of miR-7-5p. MiR-7-5p reversed the effect of LINC01272 on viability, multiplication, apoptosis and expression of miR-7-5p and CRLS1 as well as apoptosis-related factors (Bcl-2, Bax and cleaved caspase-3). LINC01272 suppressed cell multiplication and induced apoptosis via regulating the miR-7-5p/CRLS1 axis in LC.

Improved Pharmacokinetic Characteristics of Ursolic Acid in Rats Following Intratracheal Instillation and Nose-Only Inhalation Exposure

Ursolic acid (UA) is a common pentacyclic triterpene phytochemical with various pharmacological activities. However, UA is classified as a class IV drug in BCS system and its development as an oral drug is limited. Pulmonary delivery is an effective way to improve the bioavailability of drugs with low absorption. In this study, the differences in pharmacokinetic behaviors of UA after pulmonary and oral administration was explored in rats. Compared with oral administration, the plasma concentration of UA increased rapidly after pulmonary administration, and the bioavailability increased about 80 times. UA instantly accumulated in the lungs after pulmonary administration, and the pulmonary AUC0-t/dose increased by 114 times compared to oral dosing. Incubation experiments showed that the metabolism of UA in rat lung microsomes was significantly reduced compared with that in liver microsomes, in which the clearance rate of phase I and phase II metabolism was reduced by 14.7 times and 1.4 times respectively. These results indicated that pulmonary administration could improve the bioavailability of UA and reduce its metabolism. This study not only provides a preferable route of administration for the application of UA but also offers new insights for the development of phytochemical drug candidates with poor pharmacokinetic properties.

Plants derived therapeutic strategies targeting chronic respiratory diseases: Chemical and immunological perspective

The apparent predicament of the representative chemotherapy for managing respiratory distress calls for an obligatory deliberation for identifying the pharmaceuticals that effectively counter the contemporary intricacies associated with target disease. Multiple, complex regulatory pathways manifest chronic pulmonary disorders, which require chemotherapeutics that produce composite inhibitory effect. The cost effective natural product based molecules hold a high fervor to meet the prospects posed by current respiratory-distress therapy by sparing the tedious drug design and development archetypes, present a robust standing for the possible replacement of the fading practice of poly-pharmacology, and ensure the subversion of a potential disease relapse. This study summarizes the experimental evidences on natural products moieties and their components that illustrates therapeutic efficacy on respiratory disorders.

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Plant derived therapeutics for managing chronic respiratory disorders.

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Activity of natural product based molecules on key regulatory pathways of COPD.

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Preclinical evidence for the efficacy of natural product moieties.

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Clinical significance of plant derived molecules in pulmonary distress.

Synthesis and antitumor activity evaluation of ursolic acid derivatives

Eighteen uronic acid derivatives were designed and synthesized, and the cytotoxicities in vitro of two cancer cell lines (BEL7402 and SGC7901) were evaluated by MTT assay. The results showed that the inhibitory rate of the compounds on both cell lines was significantly higher than the parent compound. The IC50 of compounds II4, II6, III4, and III6 are comparable or stronger than the positive control drug, the interactions between compounds II4, II6, III4, III6, and NF-κB were also studied by docking simulations.

Histone Methyltransferase Setd7 Regulates Nrf2 Signaling Pathway by Phenethyl Isothiocyanate and Ursolic Acid in Human Prostate Cancer Cells

SCOPE

This study aims to investigate the role of the epigenetic regulator SET domain-containing lysine methyltransferase 7 (Setd7) in regulating the antioxidant Nrf2 pathway in prostate cancer (PCa) cells and examines the effects of two phytochemicals, phenethyl isothiocyanate (PEITC) and ursolic acid (UA).

METHODS AND RESULTS

Lentivirus-mediated shRNA knockdown of Setd7 in LNCaP and PC-3 cells decreases the expression of downstream Nrf2 targets, such as NAD(P)H: quinone oxidoreductase 1 (Nqo1) and glutathione S-transferase theta 2 (Gstt2). Downregulation of Setd7 decreases soft agar colony formation ability of PCa cells. Knockdown of Setd7 increases reactive oxygen species (ROS) generation. Furthermore, Setd7 knockdown attenuates Nqo1 and Gstt2 expression in response to H2 O2 challenge, whereas increased DNA damage is observed in Setd7 knockdown cells in comet assay. Interestingly, Setd7 expression could be induced by the dietary phytochemicals PEITC and UA. Chromatin immunoprecipitation (ChIP) assays show that Setd7 knockdown decreased H3K4me1 enrichment in the Nrf2 and Gstt2 promoter regions, while PEITC and UA treatments elevated the enrichment.

CONCLUSION

Taken together, these results indicate that Setd7 knockdown decreases Nrf2 and Nrf2-target genes expression and that PEITC and UA induce Setd7 expression, which activates the Nrf2/antioxidant response element (ARE) signaling pathway and protects DNA from oxidative damage.

Phenolics from Barleria cristata var. Alba as carcinogenesis blockers against menadione cytotoxicity through induction and protection of quinone reductase

Background

There are increasing interests in natural compounds for cancer chemoprevention. Blocking agents represent an important class of chemopreventive compounds. They prevent carcinogens from undergoing metabolic activation and thereby suppressing their interaction with cellular macromolecular targets.

Methods

The effect of phenolic compounds isolated from Barleria cristata var. alba as chemopreventive agent was evaluated. The ethyl acetate fraction of B. cristata was subjected to different chromatographic techniques for isolation of its major phenolic compounds. The isolated compounds were evaluated for their potential to induce the cancer chemopreventive enzyme marker NAD(P)H quinonereductase 1 (NQO1) in murine Hepa-1c1c7 cell model.

Results

The ethyl acetate fraction of B. cristata var. alba yielded five known compounds identified as verbascoside (1), isoverbascoside (2), dimethoxyverbascoside (3), p-hydroxy benzoic acid (4), and apigenin-7-O-glucoside (5). Among the tested compounds, isoverbascoside (2) was shown to potently induce the activity of the enzyme in a dose –dependent manner. As a functional assay for detoxification, compound 2 was the strongest to protect Hepa-1c1c7 against the toxicity of menadione, a quinone substrate for NQO1.

Conclusion

This effect seemed to be attributed to the compound’s potential to induce both the catalytic activity and protein expression of NQO1 as revealed by enzyme assay and Western blotting, respectively.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2214-9) contains supplementary material, which is available to authorized users.

Tripterine alleviates lipopolysaccharide-induced airway epithelial barrier dysfunction through suppressing the Hippo pathway

Recent studies show that airway epithelial barrier dysfunction is closely associated with allergic inflammation and asthma pathogenesis.

Pharmacokinetics and Pharmacodynamics of the Triterpenoid Ursolic Acid in Regulating the Antioxidant, Anti-inflammatory, and Epigenetic Gene Responses in Rat Leukocytes

The triterpenoid ursolic acid (UA) has been proposed as a potential cancer chemopreventive agent in many preclinical and clinical studies. In the present work, we aimed to characterize the pharmacokinetics (PK) of UA and to quantitatively assess the antioxidative and anti-inflammatory effects of UA, which are potentially linked to its chemopreventive efficacy. UA was administered intravenously (i.v., 20 mg/kg) or by oral gavage (100 mg/kg) to male Sprague-Dawley rats, and blood samples were collected at a series of designated time points. The plasma concentration of UA was determined using a validated liquid chromatography-mass spectrometry (LC-MS) approach. A biexponential decline in the UA plasma concentration was observed after i.v. dosing and was fitted to a two-compartmental model. The expression levels of phase II drug metabolism (DM)/antioxidant genes and the inflammatory iNos gene in corresponding treatment arms were measured using qPCR as a pharmacodynamic (PD) marker. The expression of phase II DM/antioxidant genes increased and peaked approximately 3 h after 20 mg/kg UA treatment. In a lipopolysaccharide (LPS)-induced acute inflammation model, UA inhibited LPS-stimulated iNos expression and that of the epigenetic markers the DNA methyltransferases (DNMTs) and histone deacetylases (HDACs) in leukocytes. A PK-PD model using Jusko's indirect response model (IDR) with transition compartments (TC) was established to describe the time delay and magnitude of the gene expression elicited by UA. The PK-PD model provided reasonable fitting linking the plasma concentration of UA simultaneously with the PD response based on leukocyte mRNA expression. Overall, our results indicate that UA is effective at inducing various phase II DM/antioxidant genes and inhibiting pro-inflammatory genes in vivo. This PK-PD modeling approach may provide a conceptual framework for the future clinical evaluation of dietary chemopreventive agents in humans.

Chemical composition of Ocimum sanctum by LC-ESI-MS/MS analysis and its protective effects against smoke induced lung and neuronal tissue damage in rats

Smoke induced oxidative stress is known to cause various cancers and associated health problems including lung cancer. Herbal extracts have been reported as antioxidant supplements which attenuate free radical induced oxidative damage of tissues, among which Ocimum sanctum has been reported as the elixir of life due to its innumerable health benefits. In the present study, we investigated the protective effect of O. sanctum against cracker smoke induced lung and brain tissue damage. The results of the study demonstrate that O. sanctum regulates the hematological and serum biochemical parameters such as RBC, WBC, blood urea nitrogen and creatinine kinase. O. sanctum supplementation inhibited oxidative stress as analyzed by SOD, CAT enzyme levels and i-NOS, HSP-70 protein expression. O. sanctum administration also regulated neurotransmitter levels, such as serotonin, dopamine, and regulated acetylcholine esterase levels which play a vital role in neuronal function. Further O. sanctum treatment also preserved the morphology of lung and brain tissues of smoke stress induced rats as observed by histopathology and transmission electron microscope analysis. The biodistribution of O. sanctum was showed its accumulation in key tissues such as kidney, liver, lungs and heart. The LC-ESI-MS/MS analysis of O. sanctum showed the presence of polyphenols, flavonoids and fatty acids which might be responsible for the observed anti-stress effects.

Ursolic acid from apple pomace and traditional plants: A valuable triterpenoid with functional properties

Apple juice production generates a large amount of residue comprising mainly peels, seeds, and pulp, known as apple pomace. In the global context, Brazil ranks 11th in apple production and thousands of tons of apple pomace are produced every year. This by-product is little explored, since it is a rich and heterogeneous mixture, containing interesting phytochemical groups. Among them, ursolic acid (UA) has attracted attention because of its therapeutic potential. UA is a pentacyclic triterpene found too in several traditional plants, and has shown several functional properties such as antibacterial, antiprotozoal, anti-inflammatory and antitumor. Therefore, this review attempts to shed some light on the economical viability of apple and apple pomace as sources of bioactive compounds, highlighting the UA extraction, and its main functional properties published in the last 5years (2010-2015).

Ursolic Acid Ameliorates Early Brain Injury After Experimental Traumatic Brain Injury in Mice by Activating the Nrf2 Pathway

Previous studies have indicated oxidative stress and inflammatory injury as significant contributors to the secondary damage associated with traumatic brain injury (TBI). Ursolic acid (UA) has been demonstrated to exert anti-oxidative and anti-inflammatory effects on cerebral ischemia by activating the nuclear factor-erythroid 2-related factor 2 (Nrf2) pathway. However, the effects of UA on TBI remain unclear. The aim of this study is to evaluate the potential roles of UA in the activation of the Nrf2 pathway using an experimental TBI model and the underlying mechanism. Wild-type (WT) and Nrf2(-/-) mice were divided into eight groups: (1) sham; (2) TBI; (3) TBI + vehicle; (4) TBI + 50 mg/kg UA; (5) TBI + 100 mg/kg UA; (6) TBI + 150 mg/kg UA; (7) TBI + Nrf2(-/-) + vehicle; (8) TBI + Nrf2(-/-) + UA. All mice underwent the TBI with the exception of the sham group. The neurologic outcomes of the mice were evaluated at 24 h after TBI, as well as the expression of Nrf2, NQO1, HO1,SOD, GPx, and MDA. Treatment of UA significantly ameliorated brain edema and the neurological insufficiencies after TBI. In addition, UA treatment markedly strengthened the nuclear translocation of Nrf2 protein and increased the expression of NQO1 and HO1. Moreover, UA significantly increased the expression of AKT, an Nrf2 upstream factor, suggesting that UA play a neuroprotective role through the activation of the Nrf2-ARE signal pathway. On the contrary, UA showed no neuroprotective effect on the Nrf2(-/-) mice. These data indicated that UA increases the activity of antioxidant enzymes and attenuated brain injury via Nrf2 factor.

Study on the mechanisms of the bronchodilator effects of Folium Eriobotryae and the selected active ingredient on isolated guinea pig tracheal strips

CONTEXT

Folium Eriobotryae (FE), the dry leaf of Eriobotrya japonica (Thunb.) Lindl. (Rosaceae), has been widely used to treat respiratory disorders.

OBJECTIVE

To examine the bronchodilatory activity of FE and the potential mechanisms involved.

MATERIALS AND METHODS

The effects of ethyl acetate fraction of FE (EFE) (0.05-0.3 mg/mL) on the isolated tracheal strips, and ursolic acid (UA) (5-30 μg/mL) that was the main constituent of EFE, were tested in vitro. Meanwhile, acetylcholine (Ach) and histamine (His)-induced bronchospasm were conducted in vivo in guinea pig. Furthermore, mechanisms of relaxant effects of EFE and UA were evaluated in the absence and presence of specific inhibitors.

RESULTS

With in vitro studies, the contractile response evoked by Ach or His (EC50 = 0.21 and 0.16 mg/mL) was decreased by EFE, and UA caused a concentration-dependent relaxation precontracted by His (EC50 = 23.2 μg/mL). With in vivo studies, EFE strongly prolonged preconvulsive time similar to isoprenalin. The bronchodilator effects of EFE could be blocked by propranolol (1 μM), NG-nitro-l-arginine methyl ester (l-NAME) (100 μM) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ) (1 μM). EFE also inhibited the contraction in Ca2+-free medium and produced rightward parallel displacement of CaCl2 curves. In addition, the relaxant effects of UA could only be blocked by l-NAME and ODQ.

DISCUSSION AND CONCLUSION

These results suggest that bronchodilator activities of EFE were related to activation of β-adrenoceptor and NO/cGMP pathway. Blockage of Ca2+ channels and inhibition of IP3R-mediated internal Ca2+ release were also involved. Additionally, UA produced relaxant effects by the NO/cGMP pathway.

Ursolic acid sensitizes cisplatin-resistant HepG2/DDP cells to cisplatin via inhibiting Nrf2/ARE pathway

BACKGROUND

Combinations of adjuvant sensitizers with anticancer drugs is a promising new strategy to reverse chemoresistance. Ursolic acid (UA) is one of the natural pentacyclic triterpene compounds known to have many pharmacological characteristics such as anti-inflammatory and anticancer properties. This study investigates whether UA can sensitize hepatocellular carcinoma cells to cisplatin.

MATERIALS AND METHODS

Cells were transfected with nuclear factor erythroid-2-related factor 2 (Nrf2) small interfering RNA and Nrf2 complementary DNA by using Lipofectin 2000. The cytotoxicity of cells was investigated by Cell Counting Kit 8 assay. Cell apoptosis, cell cycle, reactive oxygen species, and mitochondrial membrane potential were detected by flow cytometry fluorescence-activated cell sorting. The protein level of Nrf2, NAD(P)H quinone oxidoreductase 1 (NQO1), glutathione S-transferase (GST), and heme oxygenase-1 (HO-1) was detected by Western blot analysis.

RESULTS

The results showed that the reverse index was 2.9- and 9.69-fold by UA of 1.125 μg/mL and 2.25 μg/mL, respectively, for cisplatin to HepG2/DDP cells. UA-cisplatin combination induced cell apoptosis and reactive oxygen species, blocked the cell cycle in G0/G1 phase, and reduced the mitochondrial membrane potential. Mechanistically, UA-cisplatin dramatically decreased the expression of Nrf2 and its downstream genes. The sensibilization of UA-cisplatin combination was diminished in Nrf2 small interfering RNA-transfected HepG2/DDP cells, as well as in Nrf2 complementary DNA-transfected HepG2/DDP cells.

CONCLUSION

The results confirmed the sensibilization of UA on HepG2/DDP cells to cisplatin, which was possibly mediated via the Nrf2/antioxidant response element pathway.

Ursolic Acid--A Pentacyclic Triterpenoid with a Wide Spectrum of Pharmacological Activities

Ursolic acid (UA) is a natural terpene compound exhibiting many pharmaceutical properties. In this review the current state of knowledge about the health-promoting properties of this widespread, biologically active compound, as well as information about its occurrence and biosynthesis are presented. Particular attention has been paid to the application of ursolic acid as an anti-cancer agent; it is worth noticing that clinical tests suggesting the possibility of practical use of UA have already been conducted. Amongst other pharmacological properties of UA one can mention protective effect on lungs, kidneys, liver and brain, anti-inflammatory properties, anabolic effects on skeletal muscles and the ability to suppress bone density loss leading to osteoporosis. Ursolic acid also exhibits anti-microbial features against numerous strains of bacteria, HIV and HCV viruses and Plasmodium protozoa causing malaria.

Ursolic acid improves survival and attenuates lung injury in septic rats induced by cecal ligation and puncture

BACKGROUND

Sepsis is characterized as a systemic inflammatory response syndrome during infection, which can result in multiple organ dysfunction and death. Ursolic acid (UA), a pentacyclic triterpene acid, has been reported to have potent anti-inflammatory and antioxidant properties. The aim of this study was to detect the possible protective effects of UA on sepsis-evoked acute lung injury.

MATERIALS AND METHODS

A rat model of sepsis induced by cecal ligation and puncture (CLP) was used. Rats were injected intraperitoneally with UA (10 mg/kg) after CLP, and then the survival was determined twice a day for 4 d. The protective effects of UA on CLP-induced acute lung injury were assayed at 24 h after CLP.

RESULTS

The results revealed that UA treatment markedly improved the survival of septic rats, and attenuated CLP-induced lung injury, including reduction of lung wet/dry weight ratio, infiltration of leukocytes and proteins, myeloperoxidase activity, and malondialdehyde content. In addition, UA significantly decreased the serum levels of tumor necrosis factor-α, interleukin-6, and interleukin-1β, inhibited the expression of inducible nitric oxide synthase and cyclooxygenase-2 in the lung, which are involved in the productions of nitric oxide and prostaglandin E2.

CONCLUSIONS

These findings indicate that UA exerts protective effects on CLP-induced septic rats. UA may be a potential therapeutic agent against sepsis.

Ursolic acid inhibited growth of hepatocellular carcinoma HepG2 cells through AMPKα-mediated reduction of DNA methyltransferase 1

Hepatocellular carcinoma (HCC), the major histological subtype of primary liver cancer, remains one of the most common malignancies worldwide. Due to the complicated pathogenesis of this malignancy, the outcome for comprehensive treatment is limited. Chinese herbal medicine (CHM) is emerging as a promising choice for its multi-targets and coordinated intervention effects against HCC. Ursolic acid (UA), a natural pentacyclic triterpenoid carboxylic acid found in CHM, exerts anti-tumor effects and is emerging as an effective compound for cancer prevention and therapy. However, the molecular mechanisms underlying the action of UA remain largely unknown. In this study, we showed that UA inhibited the growth of HCC cells and induced apoptosis in the dose- and time-dependent fashion. Furthermore, we found that UA induced phosphorylation of AMP-activated protein kinase alpha (AMPKα) and suppressed the protein expression of DNA methyltransferase 1 (DNMT1) in the dose-dependent manner. The inhibitor of AMPK, compound C blocked, while an activator of AMPK, metformin augmented the effect of UA on DNMT1 expression. In addition, UA suppressed the expression of transcription factor Sp1. Conversely, overexpression of Sp1 reversed the effect of UA on DNMT1 expression and cell growth. Collectively, our results show for the first time that UA inhibits growth of HCC through AMPKα-mediated inhibition of Sp1; this in turn results in inhibition of DNMT1. This study reveals a potential novel mechanism by which UA controls growth of HCC cells and suggests that DNMT1 could be novel target for HCC chemoprevention and treatment.

Antioxidative and antiinflammatory activities of asiatic acid, glycyrrhizic acid, and oleanolic acid in human bronchial epithelial cells

Protective effects of triterpenic acids, asiatic acid (AA), glycyrrhizic acid (GA), or oleanolic acid (OA), for two human bronchial epithelial cells, 16HBE and BEAS-2B cells, against hydrogen peroxide (H2O2) induced injury were examined. Cells were pretreated by triterpenic acid at 4 or 8 μmol/L and followed by H2O2 treatment. Results showed that H2O2 significantly upregulated both Bax and cleaved caspase-3 expression, and also downregulated Bcl-2 expression in test cells. AA at these doses retained Bcl-2 expression, but GA and OA only at 8 μmol/L reserved Bcl-2 expression. Test triterpenic acids lowered cleaved caspase-3 expression dose-dependently. H2O2 treatment lowered Na(+)-K(+)-ATPase activity and mitochondrial membrane potential in cells. Triterpenic acid pretreatments significantly maintained mitochondrial membrane potential and Na(+)-K(+)-ATPase activity. H2O2 enhanced reactive oxygen species, interleukin-6, tumor necrosis factor-α, and prostaglandin E2 levels in test cells. Three triterpenic acid treatments dose-dependently reversed these changes. H2O2 promoted the protein expression of p47(phox), gp91(phox), cyclooxygenase-2 (COX-2), mitogen-activated protein kinase, and nuclear factor-κB (NF-κB). AA, GA, or OA pretreatments dose-dependently downregulated the expression of p47(phox), COX-2, NF-κB p65, and p-p38 but only at 8 μmol/L decreased gp91(phox) expression. These results support that these triterpenic acids could protect bronchial epithelial cells to attenuate apoptotic, oxidative, and inflammatory stress.

Ursolic acid differentially modulates apoptosis in skin melanoma and retinal pigment epithelial cells exposed to UV-VIS broadband radiation

The signaling pathways via mTOR (mammalian target of rapamycin) and AMPK (AMP-activated protein kinase) play key roles in transcription, translation and carcinogenesis, and may be activated by light exposure. These pathways can be modulated by naturally occurring compounds, such as the triterpenoid, ursolic acid (UA). Previously, the transcription factors p53 and NF-κB, which transactivate mitochondrial apoptosis-related genes, were shown to be differentially modulated by UA. UA-modulated apoptosis, following exposure to UV-VIS radiation (ultraviolet to visible light broadband radiation, hereafter abbreviated to UVR), is observed to correspond to differential levels of oxidative stress in retinal pigment epithelial (RPE) and skin melanoma (SM) cells. The cellular response to this phytochemical was characterized using western blot, flow cytometry, microscopy with reactive oxidative species probes MitoTracker and dihydroethidium, and membrane permeability assay. UA pretreatment potentiated cell cycle arrest and UVR-induced apoptosis selectively in SM cells while reducing photo-oxidative stress in the DNA of RPE cells presumably by antioxidant activity of UA. Mechanistically, the nuclear transportation of p65 and p53 was reduced by UA administration prior to UVR exposure while the levels of p65 and p53 nuclear transportation in SM cells were sustained at a substantially higher level. Finally, the mitochondrial functional assay showed that UVR induced the collapse of the mitochondrial membrane potential, and this effect was exacerbated by rapamycin or UA pretreatment in SM preferentially. These results were consistent with reduced proliferation observed in the clonogenic assay, indicating that UA treatment enhanced the phototoxicity of UVR, by modulating the activation of p53 and NF-κB and initiating a mitogenic response to optical radiation that triggered mitochondria-dependent apoptosis, particularly in skin melanoma cells. The study indicates that this compound has multiple actions with the potential for protecting normal cells while sensitizing skin melanoma cells to UV irradiation.

Resveratrol and P-glycoprotein inhibitors enhance the anti-skin cancer effects of ursolic acid

Ursolic acid, present in apples, rosemary, and other sources, is known to inhibit tumor formation and tumor cell viability in multiple systems, including skin. However, various cancers are resistant to ursolic acid treatment. Herein, skin carcinoma cells (Ca3/7) as compared with skin papilloma cells (MT1/2) displayed more resistance to ursolic acid-induced cytotoxicity. Interestingly, Ca3/7 cells had elevated levels of P-glycoprotein (P-gp), an ATP-dependent efflux pump that mediates resistance to chemotherapy in preclinical and clinical settings, and not only accumulated less but also more rapidly expelled the P-gp substrate rhodamine 123 (Rh123) indicating ursolic acid is transported by P-gp. To determine whether P-gp inhibition can enhance ursolic acid-mediated cytotoxicity, cells were challenged with P-gp inhibitors verapamil or cyclosporin A. Alternatively, cells were pretreated with the natural compound resveratrol, a known chemotherapy sensitizer. Verapamil and resveratrol enhanced the effects of ursolic acid in both cell lines, whereas cyclosporin A only did so in Ca3/7 cells. Similarly, verapamil inhibited Rh123 efflux in both lines, whereas cyclosporin A only inhibited Rh123 efflux in Ca3/7 cells. Resveratrol did not inhibit Rh123 efflux in either line, indicating the synergistic effects of resveratrol and ursolic acid are not manifest by inhibition of P-gp-mediated efflux of ursolic acid. These results indicate that the anti-skin cancer effects of ursolic acid are enhanced with P-gp inhibitors. In addition, resveratrol and ursolic acid interact synergistically, but not through inhibition of P-gp.

IMPLICATIONS

Resveratrol and/or p-glycoprotein inhibitors in combination with ursolic acid are an effective anti-skin cancer regimen.

Mechanistic targets and phytochemical strategies for breaking the obesity-cancer link

The prevalence of obesity, an established risk and progression factor for many cancers, has increased dramatically in many countries over the past three decades. Worldwide, an estimated 600 million adults are currently obese. Thus, a better understanding of the mechanistic links between obesity and cancer is urgently needed to identify intervention targets and strategies to offset the procancer effects of obesity. This review synthesizes the evidence on key biological mechanisms underlying the obesity-cancer association, with particular emphasis on obesity-associated enhancements in growth factor signaling, inflammation, and perturbations in the tumor microenvironment. These interrelated pathways and processes that are aberrantly regulated in obese individuals represent mechanism-based targets for disrupting the obesity-cancer link using phytochemicals.

Ursolic acid in cancer prevention and treatment: molecular targets, pharmacokinetics and clinical studies

Discovery of bioactive molecules and elucidation of their molecular mechanisms open up an enormous opportunity for the development of improved therapy for different inflammatory diseases, including cancer. Triterpenoids isolated several decades ago from various medicinal plants now seem to have a prominent role in the prevention and therapy of a variety of ailments and some have already entered Phase I clinical trials. One such important and highly investigated pentacyclic triterpenoid, ursolic acid has attracted great attention of late for its potential as a chemopreventive and chemotherapeutic agent in various types of cancer. Ursolic acid has been shown to target multiple proinflammatory transcription factors, cell cycle proteins, growth factors, kinases, cytokines, chemokines, adhesion molecules, and inflammatory enzymes. These targets can potentially mediate the chemopreventive and therapeutic effects of ursolic acid by inhibiting the initiation, promotion and metastasis of cancer. This review not only summarizes the diverse molecular targets of ursolic acid, but also provides an insight into the various preclinical and clinical studies that have been performed in the last decade with this promising triterpenoid.

Ursolic acid simultaneously targets multiple signaling pathways to suppress proliferation and induce apoptosis in colon cancer cells

Ursolic acid (UA), a natural pentacyclic triterpenoid carboxylic acid distributed in medical herbs, exerts antitumor effects and is emerging as a promising compound for cancer prevention and therapy, but its excise mechanisms of action in colon cancer cells remains largely unknown. Here, we identified the molecular mechanisms by which UA inhibited cell proliferation and induced apoptosis in human colon cancer SW480 and LoVo cells. Treatment with UA led to significant inhibitions in cell viability and clone formation and changes in cell morphology and spreading. UA also suppressed colon cancer cell migration by inhibiting MMP9 and upregulating CDH1 expression. Further studies showed that UA inhibited the phosphorylation of Akt and ERK proteins. Pretreatment with an Akt or ERK-specific inhibitor considerably abrogated the proliferation inhibition by UA. UA also significantly inhibited colon cancer cell COX-2 expression and PGE2 production. Pretreatment with a COX-2 inhibitor (celecoxib) abrogated the UA-induced cell proliferation. Moreover, we found that UA effectively promoted NF-κB and p300 translocation from cell nuclei to cytoplasm, and attenuated the p300-mediated acetylation of NF-κB and CREB2. Pretreatment with a p300 inhibitor (roscovitine) abrogated the UA-induced cell proliferation, which is reversed by p300 overexpression. Furthermore, UA treatment induced colon cancer cell apoptosis, increased the cleavage of PARP, caspase-3 and 9, and trigged the release of cytochrome c from mitochondrial inter-membrane space into cytosol. These results indicate that UA inhibits cell proliferation and induces apoptosis in colon cancer cells through simultaneous modulation of the multiple signaling pathways such as MMP9/CDH1, Akt/ERK, COX-2/PGE2, p300/NF-κB/CREB2, and cytochrome c/caspase pathways.