Anticancer effects of oleanolic acid on human melanoma cells

Simultaneous quantitation of pentacyclic triterpenoids in fruit peels using liquid chromatography-single quadrupole mass spectrometry

The simultaneous determination of pentacyclic triterpenoids, which are secondary metabolites in plants, is difficult because of the similarity in structure and minimal differences in polarity. In this study, we established a simple and sensitive method for the simultaneous determination of pentacyclic triterpenoids based on liquid chromatography-single-quadrupole mass spectrometry (LC-MS) using a C30 column. The established method completely separated 13 pentacyclic triterpenoids based on their different retention times. Furthermore, the molecular weight and reliability were confirmed for ten compounds. This method was used to quantify pentacyclic triterpenoids in acetone extracts of the peels of ten varieties of apple and eight varieties of persimmon. Therefore, this method is expected to be used in a comprehensive search for pentacyclic triterpenoids in fruit-processing residues.

Exploring the therapeutic potential of oleanolic acid and its derivatives in cancer treatment: a comprehensive review

Oleanolic acid (OA) is a triterpenoid that occurs naturally and may be isolated from various plants. Analogs of oleanolic acid can be produced artificially or naturally. The current treatments have limited selectivity and may also impact normal cells. OA and its derivatives provide a promising cancer treatment platform with greater selectivity and less toxic effects. As a result of their enhanced sensitivity, selectivity, and low toxicity, they are great options for focusing on particular biological pathways and reducing the growth of tumor cells. The effects of OA and derivatives of OA on various cancer types have been investigated. However, breast and hepatocellular malignancies are the most studied cancers. In breast cancer, derivatives such as saikosaponin A (SSa), saikosaponin B (SSb), and SZC014 influence key pathways such as the Janus kinase/signal transducer and activator of transcription (JAK/STAT), protein kinase-B (Akt), and nuclear factor-kappa B (NF-κB) pathways, inhibiting metastasis, angiogenesis, and cell migration, respectively. When a para-aminobenzoic acid (PABA)/nitric oxide (NO) derivative of OA is administered to HepG2 cells, the reactive oxygen species (ROS)/mitogen-activated protein kinase (MAPK)-mediated mitochondrial pathway causes apoptosis. Nanoformulations incorporating OA, such as OA-paclitaxel (PTX), show potential for suppressing tumor progression by inhibiting drug efflux mechanisms. Thus, exploring the interactions of OA and a few of its derivatives with various cellular pathways offers a promising approach to combating different types of cancer. This review delves into the potential of oleanolic acid and its derivatives in retarding cancer progression through their interactions with diverse cellular pathways.

Inhibition of colorectal cancer aggressiveness by Oleanolic acid through Nur77 degradation

BACKGROUND

Colorectal cancer (CRC) is the second primary malignancy in China with tough treatment challenge. Although Oleanolic acid (OA) protects against various cancers, its mechanisms in CRC are not well defined. Our previously study showed that Nur77 has CRC promoting effect. Thus, we investigated the roles of OA as Nur77 ligand and the regulatory effects on Nur77 degradation in CRC progression.

METHODS

The proliferative and metastatic phenotypes of OA was examined by CCK-8, EdU, organoid culture, would healing and transwell assays, respectively. Epithelial-mesenchymal transition (EMT) properties were assessed by Western blotting (WB). The interaction between OA and Nur77 was monitored by molecular docking and Molecular Dynamics stimulation (MD). Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene set enrichment analysis (GSEA) were employed to screen the downstream regulatory pathways. The half-time and proteasome degradation of Nur77 were treated with cycloheximide (CHX) and MG132. Co-immunoprecipitation (Co-IP) and ubiquitination assays were employed to detect direct association between Nur77 and PPARγ. Rescued experiments were performed by Nur77 agonist Cytosporone B (Csn-B) treatment. The findings were verified in xenograft and in situ models.

RESULTS

For the first time, we found the effect of OA on ubiquitination degradation. OA inhibited CRC cell survival and EMT phenotypes by suppressing Nur77. Mechanistically, OA directly bind to Nur77 and facilitated the ubiquitin degradation of Nur77. During this process, PPARγ acted as the ubiquitination activator via interacting with Nur77. Rescued experiments revealed that OA-induced inhibition was recovered by replenishing Nur77. In both subcutaneous and orthotopic CRC models, OA exhibited significant anti-tumor effect together with Nur77 inhibition.

CONCLUSION

We revealed a new regulatory effect of OA in CRC tumorigenesis via PPARγ-mediated Nur77 ubiquitin degradation.

Antitumour activity of oleanolic acid: A systematic review and meta‑analysis

Oleanolic acid (OA), a compound known for its potent antitumour properties, has been the subject of investigations in both cell and animal models. Although OA has good biological activity, its low water solubility and bioavailability limit its therapeutic use, and therefore translating the potential of OA into the clinical oncology setting remains challenging. The present systematic review and meta-analysis utilized evidence from animal model studies to gain insights into the antitumour mechanisms of OA to address the gap in understanding, and to provide guidance for future research directions and potential clinical applications. The guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses were applied in the present study and a comprehensive search was conducted across the PubMed/MEDLINE, Web of Science, Cochrane Library and Embase databases, with a cut-off date of June 30, 2023. The primary focus was on randomized controlled trials that used animal models to assess the antitumour effects of OA. The methodological quality appraisal was conducted using the Systematic Review Centre for Laboratory Animal Experimentation risk of bias tool, and tumour volume and weight served as the principal outcome measures. Data were analysed using the RevMan (version 5.3) and Stata SE11 software packages, with an assessment of heterogeneity conducted using the I2 statistical test, sensitivity analysis conducted using the leave-one-out approach, and evaluation of publication bias performed using Egger's test and funnel plot analysis. The present study demonstrated a significant inhibitory effect of OA intervention on tumour growth and a decrease in tumour weight in animal models. Despite the broad spectrum of antitumour effects exhibited by OA, further investigations are warranted to optimize the dosage and administration routes of OA to maximize its efficacy in clinical cancer treatment.

Complex Inhibitory Activity of Pentacyclic Triterpenoids against Cutaneous Melanoma In Vitro and In Vivo: A Literature Review and Reconstruction of Their Melanoma-Related Protein Interactome

Pentacyclic triterpenoids (PTs) are a class of plant metabolites with a wide range of pharmacological activities, including strong antitumor potential against skin malignancies. By acting on multiple signaling pathways that control key cellular processes, PTs are able to exert complex effects on melanoma progression in vitro and in vivo. In this review, we have analyzed the works published in the past decade and devoted to the effects of PTs, both natural and semisynthetic, on cutaneous melanoma pathogenesis, including not only their direct action on melanoma cells but also their influence on the tumor microenvironment and abberant melanogenesis, often associated with melanoma aggressiveness. Special attention will be paid to the molecular basis of the pronounced antimelanoma potency of PTs, including a detailed consideration of the pathways sensitive to PTs in melanoma cells, as well as the reconstruction of the melanoma-related protein interactome of PTs using a network pharmacology approach based on previously published experimentally verified protein targets of PTs. The information collected on the primary targets of PTs was compiled in the Protein Interactome of PTs (PIPTs) database, freely available at http://www.pipts-db.ru/, which can be used to further optimize the mechanistic studies of PTs in the context of melanoma and other malignancies. By summarizing recent research findings, this review provides valuable information to scientists working in the fields related to the evaluation of melanoma pathogenesis and development of PTs-based drug candidates.

Selectivity Screening and Structure-Cytotoxic Activity Observations of Selected Oleanolic Acid (OA)-Type Saponins from the Amaranthaceae Family on a Wiade Panel of Human Cancer Cell Lines

Plants from the Amaranthaceae family are a source of oleanolic acid (OA)-type saponins with cytotoxic activity. Two known OA-type saponins, calenduloside E and chikusetsusaponin IVa, were isolated from the roots of Chenopodium strictum Roth. Their structures were confirmed using MS and NMR techniques. This constitutes the inaugural report of the saponins in Ch. strictum. Both the isolated saponins and structurally similar compounds, momordin Ic and OA, were compared for their cytotoxicity against various cancer and normal cell lines (including skin, breast, thyroid, gastrointestinal, and prostate panels). Their effects were dose- and time-dependent, varying with the specific cell line and compound structure. A chemometric approach demonstrated the effects of the compounds on the cell lines. The study discusses the structure-activity observations. The key structural elements for potent cytotoxic activity included the free carboxyl group 28COOH in the sapogenin structure (OA) and the presence of a sugar moiety. The monodesmosides with glucuronic acid (GlcA) at the C3 position of OA were generally more cytotoxic than bidesmosides or OA alone. The addition of xylose in the sugar chain modified the activity towards the cancer cells depending on the specific cell line. OA-type saponins with GlcA (particularly calenduloside E and momordin Ic) represent a promising avenue for further investigation as potential anticancer agents.

An Update on Pentacyclic Triterpenoids Ursolic and Oleanolic Acids and Related Derivatives as Anticancer Candidates

Cancer is a global health problem, with the incidence rate estimated to reach 40% of the population by 2030. Although there are currently several therapeutic methods, none of them guarantee complete healing. Plant-derived natural products show high therapeutic potential in the management of various types of cancer, with some of them already being used in current practice. Among different classes of phytocompounds, pentacyclic triterpenoids have been in the spotlight of research on this topic. Ursolic acid (UA) and its structural isomer, oleanolic acid (OA), represent compounds intensively studied and tested in vitro and in vivo for their anticancer and chemopreventive properties. Since natural compounds can rarely be used in practice as such due to their characteristic physico-chemical properties, to tackle this problem, their derivatization has been attempted, obtaining compounds with improved solubility, absorption, stability, effectiveness, and reduced toxicity. This review presents various UA and OA derivatives that have been synthesized and evaluated in recent studies for their anticancer potential. It can be observed that the most frequent structural transformations were carried out at the C-3, C-28, or both positions simultaneously. It has been demonstrated that conjugation with heterocycles or cinnamic acid, derivatization as hydrazide, or transforming OH groups into esters or amides increases anticancer efficacy.

Exploring the Potential of Oleanolic Acid Dimers-Cytostatic and Antioxidant Activities, Molecular Docking, and ADMETox Profile

The presented work aimed to explore the potential of oleanolic acid dimers (OADs): their cytostatic and antioxidant activities, molecular docking, pharmacokinetics, and ADMETox profile. The cytostatic properties of oleanolic acid (1) and its 14 synthesised dimers (2a-2n) were evaluated against 10 tumour types and expressed as IC50 values. Molecular docking was performed with the CB-Dock2 server. Antioxidant properties were evaluated with the CUPRAC method. ADMETox properties were evaluated with the ADMETlab Manual (2.0) database. The results indicate that the obtained OADs can be effective cytostatic agents, for which the IC50 not exceeded 10.00 for many tested cancer cell lines. All OADs were much more active against all cell lines than the mother compound (1). All dimers can inhibit the interaction between the 1MP8 protein and cellular proteins with the best results for compounds 2f and 2g with unsaturated bonds within the linker. An additional advantage of the tested OADs was a high level of antioxidant activity, with Trolox equivalent for OADs 2c, 2d, 2g-2j, 2l, and 2m of approximately 0.04 mg/mL, and beneficial pharmacokinetics and ADMETox properties. The differences in the DPPH and CUPRAC assay results obtained for OADs may indicate that these compounds may be effective antioxidants against different radicals.

Redox-sensitive self-assembling polymer micelles based on oleanolic modified hydroxyethyl starch: Synthesis, characterisation, and oleanolic release

Our study aimed at developing polymer micelles that possess redox sensitivity and excellent controlled release properties. 3,3'-dithiodipropionic acid (DTDPA, Abbreviation in synthetic polymers: SS) was introduced as ROS (Reactive oxygen species)response bond and connecting arm to couple hydroxyethyl starch (HES) with oleanolic acid (OA), resulting in the synthesis of four distinct grafting ratios of HES-SS-OA. FTIR (Fourier Transform infrared spectroscopy) and 1H NMR (1H Nuclear magnetic resonance spectra) were used to verify the triumphant combination of HES-SS-OA. Polymer micelles were found to encapsulate OA in an amorphous form, as indicated by the results of XRD (X-ray diffraction) and DSC (Differential scanning calorimetry). When the OA grafting rate on HES increased from 7.72 % to 11.75 %, the particle size decreased from 297.79 nm to 201.39 nm as the polymer micelles became compact due to enhanced hydrophobicity. In addition, the zeta potential changed from -16.42 mv to -25.78 mv, the PDI (polydispersity index) decreased from 0.3649 to 0.2435, and the critical micelle concentration (CMC) decreased from 0.0955 mg/mL to 0.0123 mg/mL. Results of erythrocyte hemolysis, cytotoxicity and cellular uptake illustrated that HES-SS-OA had excellent biocompatibility and minimal cytotoxicity for AML-12 cells. Disulfide bond breakage of HES-SS-OA in the presence of H2O2 and GSH confirmed the redox sensitivity of the HES-SS-OA micelles and their excellent controlled release properties for OA. These findings suggest that HES-SS-OA can be potentially used in the future as a healthcare drug and medicine for the prevention or adjuvant treatment of inflammation.

Oleanolic acid inhibits the tumor progression by regulating Lactobacillus through the cytokine-cytokine receptor interaction pathway in 4T1-induced mice breast cancer model

The therapeutic mechanism of oleanolic acid (OA) in breast cancer has been widely reported, but little has been known about the combined effects of transcriptome and gut microbiome. In this study, the phenotypic effect of oleanolic acid on mice was tested at the end of the administration cycle, and RNA sequencing on murine tumor tissue and 16S-rRNA sequencing on intestinal contents were conducted to analyze gene expression profiles and microbial diversity between the control group and OA treated group using 4T1-induced mice breast cancer model. As a result, it has been confirmed that oleanolic acid would play a significant inhibitory effect on the development of breast tumors in mice. Based on the integrative analysis of the transcriptomic and metagenomic data, it was found that the abundance of Lactobacillus in the intestinal flora of mice significantly increased in the OA group. Moreover, the up-regulation of Il10 had a significant effect on inhibiting the tumor progression, which played a role through cytokine-cytokine receptor interaction pathway.

Progress in Antimelanoma Research of Natural Triterpenoids and Their Derivatives: Mechanisms of Action, Bioavailability Enhancement and Structure Modifications

Melanoma is one of the most dangerous forms of skin cancer, characterized by early metastasis and rapid development. In search for effective treatment options, much attention is given to triterpenoids of plant origin, which are considered promising drug candidates due to their well described anticancer properties and relatively low toxicity. This paper comprehensively summarizes the antimelanoma potential of natural triterpenoids, that are also used as scaffolds for the development of more effective derivatives. These include betulin, betulinic acid, ursolic acid, maslinic acid, oleanolic acid, celastrol and lupeol. Some lesser-known triterpenoids that deserve attention in this context are 22β-hydroxytingenone, cucurbitacins, geoditin A and ganoderic acids. Recently described mechanisms of action are presented, together with the results of preclinical in vitro and in vivo studies, as well as the use of drug delivery systems and pharmaceutical technologies to improve the bioavailability of triterpenoids. This paper also reviews the most promising structural modifications, based on structure-activity observations. In conclusion, triterpenoids of plant origin and some of their semi-synthetic derivatives exert significant cytotoxic, antiproliferative and chemopreventive effects that can be beneficial for melanoma treatment. Recent data indicate that their poor solubility in water, and thus low bioavailability, can be overcome by complexing with cyclodextrins, or the use of nanoparticles and ethosomes, thus making these compounds promising antimelanoma drug candidates for further development.

Suppression of SIRT1/FXR signaling pathway contributes to oleanolic acid-induced liver injury

Oleanolic acid (OA) is a pentacyclic triterpenoid compound used clinically for acute and chronic hepatitis. However, high dose or long-term use of OA causes hepatotoxicity, which limits its clinical application. Hepatic Sirtuin (SIRT1) participates in the regulation of FXR signaling and maintains hepatic metabolic homeostasis. This study was designed to determine whether SIRT1/FXR signaling pathway contributes to the hepatotoxicity caused by OA. C57BL/6J mice were administered with OA for 4 consecutive days to induce hepatotoxicity. The results showed that OA suppressed the expression of FXR and its downstream targets CYP7A1, CYP8B1, BSEP and MRP2 at both mRNA and protein levels, breaking the homeostasis of bile acid leading to hepatotoxicity. However, treatment with FXR agonist GW4064 noticeably attenuated hepatotoxicity caused by OA. Furthermore, it was found that OA inhibited protein expression of SIRT1. Activation of SIRT1 by its agonist SRT1720 significantly improved OA-induced hepatotoxicity. Meanwhile, SRT1720 significantly reduced the inhibition of protein expression of FXR and FXR-downstream proteins. These results suggested that OA may cause hepatotoxicity through SIRT1 dependent suppression of FXR signaling pathway. In vitro experiments confirmed that OA suppressed protein expressions of FXR and its targets through inhibition of SIRT1. It was further revealed that silencing of HNF1α with siRNA significantly weakened regulatory effects of SIRT1 on the expression of FXR as well as its target genes. In conclusion, our study reveals that SIRT1/FXR pathway is crucial in OA-induced hepatotoxicity. Activation of SIRT1/HNF1α/FXR axis may represent a novel therapeutic target for ameliorating OA and other herb-induced hepatotoxicity.

Exosomes derived from mesenchymal stem cells overexpressing miR-210 inhibits neuronal inflammation and contribute to neurite outgrowth through modulating microglia polarization

Inflammatory responses play a critical role in the progress of neurodegenerative disorders. MSC-Exos is considered to have an anti-inflammatory effect on the treatment strategy for brain injury. However, the therapeutic effect and possible mechanism of Exosomal miR-210 on microglia polarization-induced neuroinflammation and neurite outgrowth have not been reported. MSC-Exos were isolated by ultracentrifugation, identified by Nanosight NS300, transmission electron microscopy, and western bolt. In vitro, to explore the protective mechanism of MSC-Exos against neuroinflammation, the microglial BV2 cell was exposed to lipopolysaccharide to assess inflammatory changes. The intake of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil)-MSC-Exos into microglia was observed by fluorescence microscopy. The results showed that Exosomal miR-210 treatment significantly inhibited the production of nitric oxide and pro-inflammatory cytokines. Exosomal miR-210 treatment also increased the number of M2 microglia cells and inhibited M1 microglia polarization. In addition, western blot demonstrated that Exosomal miR-210 reduced neuronal apoptosis. Thus, Exosomal miR-210 attenuated neuronal inflammation and promoted neurite outgrowth. Exosomal miR-210 from MSCs attenuated neuronal inflammation and contributed to neurogenesis possibly by inhibiting microglial M1 polarization.

Cisplatin and oleanolic acid Co-loaded pH-sensitive CaCO3 nanoparticles for synergistic chemotherapy

Despite being one of the most potent anticancer agents, cisplatin (CDDP) clinical usage is limited owing to the acquired resistance and severe adverse effects including nephrotoxicity. The current work has offered a unique approach by designing a pH-sensitive calcium carbonate drug delivery system for CDDP and oleanolic acid (OA) co-delivery, with an enhanced tumor efficacy and reduced unwanted effects. Micro emulsion method was employed to generate calcium carbonate cores (CDDP encapsulated) followed by lipid coating along with the OA loading resulting in the generation of lipid-coated cisplatin/oleanolic acid calcium carbonate nanoparticles (CDDP/OA-LCC NPs). In vitro biological assays confirmed the synergistic apoptotic effect of CDDP and OA against HepG2 cells. It was further verified in vivo through the tumor-bearing nude mice model where NPs exhibited enhanced satisfactory antitumor efficacy in contrast to free drug solutions. In vivo pharmacokinetic study demonstrated that a remarkable long circulation time with a constant therapeutic concentration for both drugs could be achieved via this drug delivery system. In addition, the in vivo imaging study revealed that DiR-loaded NPs were concentrated more in tumors for a longer period of time as compared to other peritoneal tissues in tumor bearing mice, demonstrating the site specificity of the delivery system. On the other hand, hematoxylin and eosin (H&E) staining of Kunming mice kidney tissue sections revealed that OA greatly reduced CDDP induced nephrotoxicity in the formulation. Overall, these results confirmed that our pH-sensitive dual loaded drug delivery system offers a handy direction for effective and safer combination chemotherapy.

Piperlongumine induces ROS mediated apoptosis by transcriptional regulation of SMAD4/P21/P53 genes and synergizes with doxorubicin in osteosarcoma cells

Piperlongumine is a herbal drug, with well-known anti-microbial and anti-neoplastic properties. The anti-carcinogenic potential of piperlongumine has been extensively explored for breast, colorectal, lungs, pancreatic, prostate, and oral carcinoma. However, a few numbers of studies are available on its bio-activity in osteosarcoma. Therefore, the present study aimed at exploring the therapeutic potential and possible mechanisms of action of piperlongumine in three human osteosarcoma cell lines in-vitro. The cytotoxicity of piperlongumine was determined by MTT assay, which shows dose and time-dependent inhibition of MG-63, 143B and KHOS/NP cells. Piperlongumine arrest the cells in G2/M phase of cell cycle and increases reactive oxygen species production, which possibly leads to lethal oxidative stress and apoptosis. Piperlongumine treatment significantly upregulated the expression of genes BAX, P21, P53, and SMAD4; while the BCL-2, SURVIVIN, TNFA, and NFKB genes expression was found down-regulated. Furthermore, piperlongumine exposure inhibited the migration of osteosarcoma cells as the expression of migration marker genes CDH2, CTNNB1, FN1, and TWIST were found to be down-regulated. The drug combination studies show the synergistic effect of piperlongumine with the conventional chemotherapeutic drug doxorubicin in osteosarcoma cells. Taken together, the above results suggest that PL displays anticancer properties against osteosarcoma and can be used as a therapeutic agent for osteosarcoma treatment in clinical settings.

Systematic Review of Potential Anticancerous Activities of Erythrina senegalensis DC (Fabaceae)

The objective of this study was to carry out a systematic review of the substances isolated from the African medicinal plant Erythrina senegalensis, focusing on compounds harboring activities against cancer models detailed in depth herein at both in vitro and in vivo preclinical levels. The review was conducted through Pubmed and Google Scholar. Nineteen out of the forty-two secondary metabolites isolated to date from E. senegalensis displayed interesting in vitro and/or in vivo antitumor activities. They belonged to alkaloid (Erysodine), triterpenes (Erythrodiol, maniladiol, oleanolic acid), prenylated isoflavonoids (senegalensin, erysenegalensein E, erysenegalensein M, alpinumisoflavone, derrone, warangalone), flavonoids (erythrisenegalone, senegalensein, lupinifolin, carpachromene) and pterocarpans (erybraedine A, erybraedine C, phaseollin). Among the isoflavonoids called "erysenegalensein", only erysenealenseins E and M have been tested for their anticancerous properties and turned out to be cytotoxic. Although the stem bark is the most frequently used part of the plant, all pterocarpans were isolated from roots and all alkaloids from seeds. The mechanisms of action of its metabolites include apoptosis, pyroptosis, autophagy and mitophagy via the modulation of cytoplasmic proteins, miRNA and enzymes involved in critical pathways deregulated in cancer. Alpinumisoflavone and oleanolic acid were studied in a broad spectrum of cancer models both in vitro and in preclinical models in vivo with promising results. Other metabolites, including carpachromen, phaseollin, erybraedin A, erysenegalensein M and maniladiol need to be further investigated, as they display potent in vitro effects.