Ursolic acid exerts anti-cancer activity by suppressing vaccinia-related kinase 1-mediated damage repair in lung cancer cells

Ursolic acid interaction with transcription factors BRAF, V600E, and V600K: a computational approach towards new potential melanoma treatments

CONTEXT

Melanoma is one of the cancers with the highest mortality rate for its ability to metastasize. Several targets have undergone investigation for the development of drugs against this pathology. One of the main targets is the kinase BRAF (RAF, rapidly accelerated fibrosarcoma). The most common mutation in melanoma is BRAFV600E and has been reported in 50-90% of patients with melanoma. Due to the relevance of the BRAFV600E mutation, inhibitors to this kinase have been developed, vemurafenib-OMe and dabrafenib. Ursolic acid (UA) is a pentacyclic triterpene with a privileged structure, the pentacycle scaffold, which allows to have a broad variety of biological activity; the most studied is its anticancer capacity. In this work, we reported the interaction profile of vemurafenib-OMe, dabrafenib, and UA, to define whether UA has binding capacity to BRAFWT, BRAFV600E, and BRAFV600K. Homology modeling of BRAFWT, V600E, and V600K; molecular docking; and molecular dynamics simulations were carried out and interactions and residues relevant to the binding of the inhibitors were obtained. We found that UA, like the inhibitors, presents hydrogen bond interactions, and hydrophobic interactions of van der Waals, and π-stacking with I463, Q530, C532, and F583. The ΔG of ursolic acid in complex with BRAFV600K (- 63.31 kcal/mol) is comparable to the ΔG of the selective inhibitor dabrafenib (- 63.32 kcal/mol) in complex to BRAFV600K and presents a ΔG like vemurafenib-OMe with BRAFWT and V600E. With this information, ursolic acid could be considered as a lead compound for design cycles and to optimize the binding profile and the selectivity towards mutations for the development of new selective inhibitors for BRAFV600E and V600K to new potential melanoma treatments.

METHODS

The homology modeling calculations were executed on the public servers I-TASSER and ROBETTA, followed by molecular docking calculations using AutoGrid 4.2.6, AutoDockGPU 1.5.3, and AutoDockTools 1.5.6. Molecular dynamics and metadynamics simulations were performed in the Desmond module of the academic version of the Schrödinger-Maestro 2020-4 program, utilizing the OPLS-2005 force field. Ligand-protein interactions were evaluated using Schrödinger-Maestro program, LigPlot + , and PLIP (protein-ligand interaction profiler). Finally, all of the protein figures presented in this article were made in the PyMOL program.

Cucurbitacin B Inhibits the Proliferation of WPMY-1 Cells and HPRF Cells via the p53/MDM2 Axis

Modern research has shown that Cucurbitacin B (Cu B) possesses various biological activities such as liver protection, anti-inflammatory, and anti-tumor effects. However, the majority of research has primarily concentrated on its hepatoprotective effects, with limited attention devoted to exploring its potential impact on the prostate. Our research indicates that Cu B effectively inhibits the proliferation of human prostate stromal cells (WPMY-1) and fibroblasts (HPRF), while triggering apoptosis in prostate cells. When treated with 100 nM Cu B, the apoptosis rates of WPMY-1 and HPRF cells reached 51.73 ± 5.38% and 26.83 ± 0.40%, respectively. In addition, the cell cycle assay showed that Cu B had a G2/M phase cycle arrest effect on WPMY-1 cells. Based on RNA-sequencing analysis, Cu B might inhibit prostate cell proliferation via the p53 signaling pathway. Subsequently, the related gene and protein expression levels were measured using quantitative real-time PCR (RT-qPCR), immunocytochemistry (ICC), and enzyme-linked immunosorbent assays (ELISA). Our results mirrored the regulation of tumor protein p53 (TP53), mouse double minute-2 (MDM2), cyclin D1 (CCND1), and thrombospondin 1 (THBS1) in Cu B-induced prostate cell apoptosis. Altogether, Cu B may inhibit prostate cell proliferation and correlate to the modulation of the p53/MDM2 signaling cascade.

Unraveling the Impact of Six Pentacyclic Triterpenes Regulating Metabolic Pathways on Lung Carcinoma Cells

Recently, there has been great interest in plant-derived compounds known as phytochemicals. The pentacyclic oleanane-, ursane-, and lupane-type triterpenes are phytochemicals that exert significant activity against diseases like cancer. Lung cancer is the leading cause of cancer-related death worldwide. Although chemotherapy is the treatment of choice for lung cancer, its effectiveness is hampered by the dose-limiting toxic effects and chemoresistance. Herein, we investigated six pentacyclic triterpenes, oleanolic acid, ursolic acid, asiatic acid, betulinic acid, betulin, and lupeol, on NSCLC A549 cells. These triterpenes have several structural variations that can influence the activation/inactivation of key cellular pathways. From our results, we determined that most of these triterpenes induced apoptosis, S-phase and G2/M-phase cycle arrest, the downregulation of ribonucleotide reductase (RR), reactive oxygen species, and caspase 3 activation. For chemoresistance markers, we found that most triterpenes downregulated the expression of MAPK/PI3K, STAT3, and PDL1. In contrast, UrA and AsA also induced DNA damage and autophagy. Then, we theoretically determined other possible molecular targets of these triterpenes using the online database ChEMBL. The results showed that even slight structural changes in these triterpenes can influence the cellular response. This study opens up promising perspectives for further research on the pharmaceutical role of phytochemical triterpenoids.

Ursolic Acid's Alluring Journey: One Triterpenoid vs. Cancer Hallmarks

Cancer is a multifactorial disease characterized by various hallmarks, including uncontrolled cell growth, evasion of apoptosis, sustained angiogenesis, tissue invasion, and metastasis, among others. Traditional cancer therapies often target specific hallmarks, leading to limited efficacy and the development of resistance. Thus, there is a growing need for alternative strategies that can address multiple hallmarks concomitantly. Ursolic acid (UA), a naturally occurring pentacyclic triterpenoid, has recently emerged as a promising candidate for multitargeted cancer therapy. This review aims to summarize the current knowledge on the anticancer properties of UA, focusing on its ability to modulate various cancer hallmarks. The literature reveals that UA exhibits potent anticancer effects through diverse mechanisms, including the inhibition of cell proliferation, induction of apoptosis, suppression of angiogenesis, inhibition of metastasis, and modulation of the tumor microenvironment. Additionally, UA has demonstrated promising activity against different cancer types (e.g., breast, lung, prostate, colon, and liver) by targeting various cancer hallmarks. This review discusses the molecular targets and signaling pathways involved in the anticancer effects of UA. Notably, UA has been found to modulate key signaling pathways, such as PI3K/Akt, MAPK/ERK, NF-κB, and Wnt/β-catenin, which play crucial roles in cancer development and progression. Moreover, the ability of UA to destroy cancer cells through various mechanisms (e.g., apoptosis, autophagy, inhibiting cell growth, dysregulating cancer cell metabolism, etc.) contributes to its multitargeted effects on cancer hallmarks. Despite promising anticancer effects, this review acknowledges hurdles related to UA's low bioavailability, emphasizing the need for enhanced therapeutic strategies.

Targeting Apoptotic Pathway of Cancer Cells with Phytochemicals and Plant-Based Nanomaterials

Apoptosis is the elimination of functionally non-essential, neoplastic, and infected cells via the mitochondrial pathway or death receptor pathway. The process of apoptosis is highly regulated through membrane channels and apoptogenic proteins. Apoptosis maintains cellular balance within the human body through cell cycle progression. Loss of apoptosis control prolongs cancer cell survival and allows the accumulation of mutations that can promote angiogenesis, promote cell proliferation, disrupt differentiation, and increase invasiveness during tumor progression. The apoptotic pathway has been extensively studied as a potential drug target in cancer treatment. However, the off-target activities of drugs and negative implications have been a matter of concern over the years. Phytochemicals (PCs) have been studied for their efficacy in various cancer cell lines individually and synergistically. The development of nanoparticles (NPs) through green synthesis has added a new dimension to the advancement of plant-based nanomaterials for effective cancer treatment. This review provides a detailed insight into the fundamental molecular pathways of programmed cell death and highlights the role of PCs along with the existing drugs and plant-based NPs in treating cancer by targeting its programmed cell death (PCD) network.

Ursolic Acid Analogs as Potential Therapeutics for Cancer

Ursolic acid (UA) is a pentacyclic triterpene isolated from a large variety of vegetables, fruits and many traditional medicinal plants. It is a structural isomer of Oleanolic Acid. The medicinal application of UA has been explored extensively over the last two decades. The diverse pharmacological properties of UA include anti-inflammatory, antimicrobial, antiviral, antioxidant, anti-proliferative, etc. Especially, UA holds a promising position, potentially, as a cancer preventive and therapeutic agent due to its relatively non-toxic properties against normal cells but its antioxidant and antiproliferative activities against cancer cells. Cell culture studies have shown interference of UA with multiple pharmacological and molecular targets that play a critical role in many cells signaling pathways. Although UA is considered a privileged natural product, its clinical applications are limited due to its low absorption through the gastro-intestinal track and rapid elimination. The low bioavailability of UA limits its use as a therapeutic drug. To overcome these drawbacks and utilize the importance of the scaffold, many researchers have been engaged in designing and developing synthetic analogs of UA via structural modifications. This present review summarizes the synthetic UA analogs and their cytotoxic antiproliferative properties reported in the last two decades.

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.

Microfluidic platform for studying the anti-cancer effect of ursolic acid on tumor spheroid

At present, the probability that a new anti-tumor drug will eventually succeed in clinical trials is extremely low. In order to make up for this shortcoming, the use of a three-dimensional (3D) cell culture model for secondary screening is often necessary. Cell spheroid is the easiest 3D model tool for drug screening. In this study, the microfluidic chip with a microwell array was manufactured, which could allow the formation of tumor spheroids with uniform size and easily retrieve cell spheroids from the chip. Cell spheroids were successfully cultured for over 15 days and the survival rate was as high as 80%. Subsequently, cellular response to the ursolic acid (UA) was observed on the chip. Compared to the monolayer culture cells in vitro, the tumor spheroids showed minor levels of epithelial-mesenchymal transition fluctuation after drug treatment. The mechanism of cell spheroid resistance to UA was further verified by detecting the expression level of upstream pathway proteins. But the invasive ability of tumor spheroids was attenuated when the duration of action of UA extended. The anti-cancer effect of UA was innovatively evaluated on breast cancer by using the microfluidic device, which could provide a basis and direction for future preclinical research on UA.

HNRNP A1 Promotes Lung Cancer Cell Proliferation by Modulating VRK1 Translation

THeterogeneous nuclear ribonucleoprotein (HNRNP) A1 is the most abundant and ubiquitously expressed member of the HNRNP protein family. In recent years, it has become more evident that HNRNP A1 contributes to the development of neurodegenerative diseases. However, little is known about the underlying role of HNRNP A1 in cancer development. Here, we report that HNRNP A1 expression is significantly increased in lung cancer tissues and is negatively correlated with the overall survival of patients with lung cancer. Additionally, HNRNP A1 positively regulates vaccinia-related kinase 1 (VRK1) translation via binding directly to the 3′ untranslated region (UTR) of VRK1 mRNA, thus increasing cyclin D1 (CCND1) expression by VRK1-mediated phosphorylation of the cAMP response element–binding protein (CREB). Furthermore, HNRNP A1 binding to the cis-acting region of the 3′UTR of VRK1 mRNA contributes to increased lung cancer cell proliferation. Thus, our study unveils a novel role of HNRNP A1 in lung carcinogenesis via post-transcriptional regulation of VRK1 expression and suggests its potential as a therapeutic target for patients with lung cancer.

Ursolic acid inhibits the invasiveness of A498 cells via NLRP3 inflammasome activation

Renal cell cancer is a common malignant tumor of the urinary system. Ursolic acid (UA) serves an important antitumor role in certain types of cancer, such as lung cancer, breast cancer and hepatocellular carcinoma; however, to the best of our knowledge, the effect of UA on renal cancer has not yet been investigated. In the present study, A498 cells were treated with different concentrations of UA for 12, 24 and 48 h, and then MCC950, an inhibitor of the NLR family pyrin domain-containing 3 (NLRP3) receptor, was added to block NLRP3 signaling. The proliferation of A498 cells was analyzed using an MTS assay and invasiveness was analyzed using a Transwell assay. The expression levels of NLRP3, cleaved caspase-1, IL-1β and MMP-2 were detected using western blotting. The present results demonstrated that the invasiveness of A498 cells was significantly decreased following UA treatment (P<0.05), while expression levels of NLRP3, cleaved caspase-1 and IL-1β were significantly increased, and MMP-2 expression was decreased following UA stimulation (P<0.05). This was reversed by MCC950 treatment (P<0.05), with the exception of NLRP3. In conclusion, the present results indicated that UA exposure decreased the proliferation and invasiveness of A498 cells. Additionally, UA exposure significantly decreased MMP-2 production and induced the activation of NLRP3 inflammasome, which was reversed by MCC950 treatment, indicating that NLRP3 activation may be involved in UA inhibition of A498 cell invasiveness.

Ursolic Acid-Based Derivatives as Potential Anti-Cancer Agents: An Update

Ursolic acid is a pharmacologically active pentacyclic triterpenoid derived from medicinal plants, fruit, and vegetables. The pharmacological activities of ursolic acid have been extensively studied over the past few years and various reports have revealed that ursolic acid has multiple biological activities, which include anti-inflammatory, antioxidant, anti-cancer, etc. In terms of cancer treatment, ursolic acid interacts with a number of molecular targets that play an essential role in many cell signaling pathways. It suppresses transformation, inhibits proliferation, and induces apoptosis of tumor cells. Although ursolic acid has many benefits, its therapeutic applications in clinical medicine are limited by its poor bioavailability and absorption. To overcome such disadvantages, researchers around the globe have designed and developed synthetic ursolic acid derivatives with enhanced therapeutic effects by structurally modifying the parent skeleton of ursolic acid. These structurally modified compounds display enhanced therapeutic effects when compared to ursolic acid. This present review summarizes various synthesized derivatives of ursolic acid with anti-cancer activity which were reported from 2015 to date.

Effect of Oleanolic Acid on Apoptosis and Autophagy of SMMC-7721 Hepatoma Cells

BACKGROUND Liver cancer is a common cancer with high morbidity and mortality. Due to the large toxic side effects of chemotherapeutic drugs and the overexpression of multidrug resistance genes in liver cancer, no effective chemotherapeutic drug has yet been found. Therefore, the search for a highly effective, low-toxic, and safe natural anticancer therapy is a hot issue. MATERIAL AND METHODS SMMC-7721 cells (a hepatocellular carcinoma cell line) were treated with different concentrations of oleanolic acid (OA) plus autophagy inhibitor 3-methyladenine (3-MA) (3-MA+OA) or chloroquine (CQ) plus OA (CQ+OA). We used MTT and Hoechst 33258 staining methods to determine the proliferation and apoptotic effect of OA on cells. Flow cytometry was used to detect apoptosis. Mitochondrial function was assessed by measuring mitochondrial membrane potential and adenosine triphosphate (ATP) concentration. To evaluate the ability of OA on apoptosis and autophagy mechanisms on SMMC 7721 cells, the related protein expression for apoptosis, autophagy, and the autophagic pathway were detected and analyzed by western blot. RESULTS OA can inhibit and induce apoptosis of SMMC-7721 in a dose-dependent manner. Compared with the control group, OA significantly reduced the intracellular mitochondrial membrane potential, and the intracellular ATP concentration was also significantly reduced. Moreover, OA reduced the expression of p-Akt and p-mTOR. The expression of p62 was decreased, and LC3-II and Beclin-1 protein expression levels increased. After inhibiting autophagy with 3-MA or CQ, compared with OA alone, cell mitochondrial membrane potential and ATP concentration were significantly reduced, cell p62 expression was reduced, and LC3-II expression was increased, apoptosis-related protein Bax protein was increased, and Bcl-2 protein was decreased, which suggested that 3-MA or CQ treatment increased OA-induced apoptosis of SMMC-7721 cells. This suggested that OA activated autophagy of SMMC-7721 cells in a protective autophagic manner. CONCLUSIONS The study findings suggest that OA combined with autophagy inhibitor 3-MA can better exert its anticancer effect.

Epigenetics/epigenomics of triterpenoids in cancer prevention and in health

Triterpenoids are a powerful group of phytochemicals derived from plant foods and herbs. Many reports have shown that they possess chemopreventive and chemotherapeutic effects not only in cell lines and animal models but also in clinical trials. Because epigenetic changes could potentially occur in the early stages of carcinogenesis preceding genetic mutations, epigenetics are considered promising targets in early interventions against cancer using epigenetic bioactive substances. The biological properties of triterpenoids in cancer prevention and in health have multiple mechanisms, including antioxidant and anti-inflammatory activities, cell cycle regulation, as well as epigenetic/epigenomic regulation. In this review, we will discuss and summarize the latest advances in the study of the pharmacological effects of triterpenoids in cancer chemoprevention and in health, including the epigenetic machinery.

Investigating the effect of radiosensitizer for Ursolic Acid and Kamolonol Acetate ‌ on HCT-116 cell line

PURPOSE

The aim of this study was evaluating the cytotoxic and radiosensitizing effects of Ursolic Acid (UA) and Kamolonol Acetate (KA) on HCT116 cell line and finally investigating the functional role of NF-κB and CCND1 genes in the radiosensitizing activity of UA and KA.

MATERIALS AND METHOD

The cytotoxic effects of UA and KA by MTT assay was evaluated on HCT-116. Clonogenic assay was performed to investigate of radiosensitizing effects of UA and KA on HCT116. To assessment the expression levels of NF-κB and CCND1 genes, real-time PCR method was used.

RESULTS

The results of MTT assay revealed that UA and KA have cytotoxic effects on HCT116 cell line. According to clonogenic assay, survival fraction of treated cells with UA and KA has been decreased compared to the survival fraction of untreated cells. UA and KA lead to the decrease in the expression level of NF-κB. Synergistic effect of radiosensitizing agents with radiation was only approved for UA and 2 Gy of radiation.

CONCLUSION

Based on our study, UA and KA have cytotoxic effects on HCT116 cell line. Furthermore, UA may lead to radiosensitization of human colorectal tumor cells by NF-κB1 and CCND1signaling pathways.

Reviewing the role of P2Y receptors in specific gastrointestinal cancers

Extracellular nucleotides are important intercellular signaling molecules that were found enriched in the tumor microenvironment. In fact, interfering with G protein-coupled P2Y receptor signaling has emerged as a promising therapeutic alternative to treat aggressive and difficult-to-manage cancers such as those affecting the gastrointestinal system. In this review, we will discuss the functions of P2Y receptors in gastrointestinal cancers with an emphasis on colorectal, hepatic, and pancreatic cancers. We will show that P2Y2 receptor up-regulation increases cancer cell proliferation, tumor growth, and metastasis in almost all studied gastrointestinal cancers. In contrast, we will present P2Y6 receptor as having opposing roles in colorectal cancer vs. gastric cancer. In colorectal cancer, the P2Y6 receptor induces carcinogenesis by inhibiting apoptosis, whereas P2Y6 suppresses gastric cancer tumor growth by reducing β-catenin transcriptional activity. The contribution of the P2Y11 receptor in the migration of liver and pancreatic cancer cells will be compared to its normal inhibitory function on this cellular process in ciliated cholangiocytes. Hence, we will demonstrate that the selective inhibition of the P2Y12 receptor activity in platelets was associated to a reduction in the risk of developing colorectal cancer and metastasis formation. We will succinctly review the role of P2Y1, P2Y4, P2Y13, and P2Y14 receptors as the knowledge for these receptors in gastrointestinal cancers is sparse. Finally, redundant ligand selectivity, nucleotide high lability, cell context, and antibody reliability will be presented as the main difficulties in defining P2Y receptor functions in gastrointestinal cancers.

Ursolic acid promotes apoptosis and mediates transcriptional suppression of CT45A2 gene expression in non-small-cell lung carcinoma harbouring EGFR T790M mutations

BACKGROUND AND PURPOSE

In non-small-cell lung carcinoma (NSCLC) patients, the L858R/T790M mutation of the epithelial growth factor receptor (EGFR) is a major cause of acquired resistance to EGFR-TKIs treatment that limits their therapeutic efficacy. Identification of drugs that can preferentially kill the NSCLC harbouring L858R/T790M mutation is therefore critical. Here, we have evaluated the effects of ursolic acid, an active component isolated from herbal sources, on erlotinib-resistant H1975 cells that harbour the L858R/T790M mutation.

EXPERIMENTAL APPROACH

Gene expression omnibus (GEO) profiles analyses was applied to detect differentially expressed genes in NSCLC cells harbouring EGFR mutation. AnnexinV-FITC/PI, TUNEL staining, MTT, wound healing, RT-PCR, qRT-PCR, western blots, immunostaining, dual-luciferase reporters and ChIP-PCR were utilized to investigate the effects of ursolic acid in vitro and in vivo.

KEY RESULTS

The cancer/testis antigen family 45 member A2 (CT45A2) was highly expressed in H1975 cells. Ectopic expression of CT45A2 in H1975 cells increased cell proliferation and motility in vitro. Silencing the CT45A2 expression strongly attenuated H1975 cells motility and growth. The anti-cancer effect of ursolic acid was critically dependent on CT45A2 expression in H1975 cells. Ursolic acid suppressed CT45A2 gene transcription mediated by transcriptional factor TCF4 and β-catenin signalling.

CONCLUSIONS AND IMPLICATIONS

CT45A2 is a novel oncogene for NSCLC with an EGFR T790 mutation. Ursolic acid induced apoptosis and inhibited proliferation of H1975 cells by negatively regulating the β-catenin/TCF4/CT45A2 signalling pathway. Therefore, ursolic acid may be a potential candidate treatment for NSCLC harbouring the EGFR-L858R/T790M mutation.

Ursolic and Oleanolic Acids Induce Mitophagy in A549 Human Lung Cancer Cells

Ursolic and oleanolic acids are natural isomeric triterpenes known for their anticancer activity. Here, we investigated the effect of triterpenes on the viability of A549 human lung cancer cells and the role of autophagy in their activity. The induction of autophagy, the mitochondrial changes and signaling pathway stimulated by triterpenes were systematically explored by confocal microscopy and western blotting. Ursolic and oleanolic acids induce autophagy in A549 cells. Ursolic acid activates AKT/mTOR pathways and oleanolic acid triggers a pathway independent on AKT. Both acids promote many mitochondrial changes, suggesting that mitochondria are targets of autophagy in a process known as mitophagy. The PINK1/Parkin axis is a pathway usually associated with mitophagy, however, the mitophagy induced by ursolic or oleanolic acid is just dependent on PINK1. Moreover, both acids induce an ROS production. The blockage of autophagy with wortmannin is responsible for a decrease of mitochondrial membrane potential (Δψ) and cell death. The wortmannin treatment causes an over-increase of p62 and Nrf2 proteins promote a detoxifying effect to rescue cells from the death conducted by ROS. In conclusion, the mitophagy and p62 protein play an important function as a survival mechanism in A549 cells and could be target to therapeutic control.

Pyrazine-Fused Triterpenoids Block the TRPA1 Ion Channel in Vitro and Inhibit TRPA1-Mediated Acute Inflammation in Vivo

TRPA1 is a nonselective cation channel, most famously expressed in nonmyelinated nociceptors. In addition to being an important chemical and mechanical pain sensor, TRPA1 has more recently appeared to have a role also in inflammation. Triterpenoids are natural products with anti-inflammatory and anticancer effects in experimental models. In this paper, 13 novel triterpenoids were created by synthetically modifying betulin, an abundant triterpenoid of the genus Betula L., and their TRPA1-modulating properties were examined. The Fluo 3-AM protocol was used in the initial screening, in which six of the 14 tested triterpenoids inhibited TRPA1 in a statistically significant manner. In subsequent whole-cell patch clamp recordings, the two most effective compounds (pyrazine-fused triterpenoids 8 and 9) displayed a reversible and dose- and voltage-dependent effect to block the TRPA1 ion channel at submicromolar concentrations. Interestingly, the TRPA1 blocking action was also evident in vivo, as compounds 8 and 9 both alleviated TRPA1 agonist-induced acute paw inflammation in mice. The results introduce betulin-derived pyrazine-fused triterpenoids as promising novel antagonists of TRPA1 that are potentially useful in treating diseases with a TRPA1-mediated adverse component.

Ursolic acid: An overview on its cytotoxic activities against breast and colorectal cancer cells

Ursolic acid (UA) is a pentacyclic triterpene of the ursane type. As a common chemical constituent among species of the family Lamiaceae, UA possesses a broad spectrum of pharmacological properties. This overview focuses on the anticancer properties of UA against breast cancer (BC) and colorectal cancer (CRC) that are most common among women and men, respectively. In vitro studies have shown that UA inhibited the growth of BC and CRC cell lines through various molecular targets and signaling pathways. There are several in vivo studies on the cytotoxic activity of UA against BC and CRC. UA also inhibits the growth of other types of cancer. Studies on structural modifications of UA have shown that the -OH groups at C3 and at C28 are critical factors influencing the cytotoxic activity of UA and its derivatives. Some needs for future research are suggested. Sources of information were from ScienceDirect, Google Scholar and PubMed.

Continued poxvirus research: From foe to friend

The eradication of smallpox is one of the greatest medical successes in history. Vaccinia virus was made famous by being the virus used in the live vaccine that enabled this feat. Nearly 40 years on from that success, this prototypical poxvirus continues to empower the exploration of fundamental biology and the potential to develop therapeutics against some of the major causes of death and disease in the modern world.

Induction of apoptosis by in vitro and in vivo plant extracts derived from Menyanthes trifoliata L. in human cancer cells

Menyanthes trifoliata L. has been used in traditional medicine for centuries. It exists in Asia, Europe, North America and in Morocco and is exploited as a remedy for anemia and lack of appetite. This plant shows many pharmacological properties, but its most interesting one is its anti-cancer potential. The present study examines the induction of apoptosis in grade IV glioma cells after treatment with the extracts from aerial part and root of M. trifoliata plants derived from in vitro (MtAPV and MtRV, respectively) and from soil (MtAPS and MtRS, respectively) and presents the first comparison of the biological effects of four different extracts of M. trifoliata against glioblastoma cells. The root extracts of M. trifoliata plants were found to exhibit cytotoxic effects against grade IV glioma cells, but not normal human astrocytes. HPLC analysis demonstrated the presence of various polyphenolic compounds, including sinapinic acid, ferulic acid, syringic acid and vanilic acid. Higher amount of pentacyclic triterpene (betulinic acid) was also found in MtRV extract. The growth inhibition of human grade IV glioma cells mediated by MtRV extract appears to be associated with apoptosis and G2/M phase cell cycle arrest, and altered expression of the pro- and anti-apoptotic genes (Bax, Bcl-2, Cas-3 and TP53) and proteins (Bax, Bcl-2, Cas-3 and p53), as well as decreased mitochondrial membrane potential. Our results indicate that M. trifoliata gives promising results as an anti-cancer agent for human glioblastoma cell lines. However, further research is necessary in view of its therapeutic use.

Crystal structure of human vaccinia-related kinase 1 in complex with AMP-PNP, a non-hydrolyzable ATP analog

Vaccinia-related kinase 1 (VRK1), a serine/threonine mitotic kinase, is widely over-expressed in dividing cells and regarded as a cancer drug target primarily due to its function as an early response gene in cell proliferation. However, the mechanism of VRK1 phosphorylation and substrate activation is not well understood. More importantly even the molecular basis of VRK1 interaction with its cofactor, adenosine triphosphate (ATP), is unavailable to-date. As designing specific inhibitors remains to be the major challenge in kinase research, such a molecular understanding will enable us to design ATP-competitive specific inhibitors of VRK1. Here we report the molecular characterization of VRK1 in complex with AMP-PNP, a non-hydrolyzable ATP-analog, using NMR titration followed by the co-crystal structure determined upto 2.07 Å resolution. We also carried out the structural comparison of the AMP-PNP bound-form with its apo and inhibitor-bound counterparts, which has enabled us to present our rationale toward designing VRK1-specific inhibitors.

P2Y2 Receptor Functions in Cancer: A Perspective in the Context of Colorectal Cancer

Purinergic signaling has recently emerged as a network of signaling molecules, enzymes and receptors that coordinates the action and behavior of cancerous cells. Extracellular adenosine 5' triphosphate activates a plethora of P2 nucleotide receptors that can putatively modulate cancer cell proliferation, survival and dissemination. In this context, the G protein-coupled P2Y₂ receptor was identified as one of the entities coordinating the cellular and molecular events that characterize cancerous cells. In this chapter, we will look at the contribution of the P2Y₂ receptor in cancer outcomes and use this information to demonstrate that the P2Y₂ receptor represents a drug target of interest in the setting of colorectal cancer, for which the role and function of this receptor is poorly defined. More particularly, we will review how the P2Y₂ receptor modulates cancer cell proliferation and survival, while promoting cell dissemination and formation of metastases. Finally, we will investigate how the P2Y₂ receptor can contribute to the detrimental development of drug resistance that is often observed in cancerous cells.

Natural agents mediated autophagic signal networks in cancer

Recent studies suggested that natural compounds are important in finding targets for cancer treatments. Autophagy (“self-eating”) plays important roles in multiple diseases and acts as a tumor suppressor in cancer. Here, we examined the molecular mechanism by which natural agents regulate autophagic signals. Understanding the relationship between natural agents and cellular autophagy may provide more information for cancer diagnosis and chemoprevention.

[Effect of ursolic acid on proliferation and apoptosis of human osteosarcoma cell line U2-OS]

Objective

To investigate the effect of ursolic acid on the proliferation and apoptosis of human osteosarcoma cell line U2-OS and analyze its mechanism.

Methods

Human osteosarcoma cell line U2-OS was divided into 4 groups, which was cultured with ursolic acid of 0, 10, 20, and 40 μmol/L, respectively. At 0, 24, 48, and 72 hours after being cultured, the cell proliferation ability was detected by cell counting kit 8 (CCK-8). At 48 hours, the effects of ursolic acid on cell cycle and apoptosis of U2-OS cells were measured by flow cytometry. Besides, the expressions of cyclin D1 and Caspase-3 were detected by real-time fluorescent quantitative PCR and Western blot.

Results

CCK-8 tests showed that the absorbance ( A) value of each group was not significant at 0 and 24 hours ( P>0.05); but the differences between groups were significant at 48 and 72 hours ( P<0.05). Flow cytometry results showed that, with the ursolic acid concentration increasing, the G 1 phase of U2-OS cells increased, the S phase and G 2/M phase decreased, and cell apoptosis rate increased gradually. There were significant differences between groups ( P<0.05). Compared with the 0 μmol/L group, the relative expressions of cyclin D1 mRNA and protein in 10, 20, and 40 μmol/L groups significantly decreased ( P<0.05); whereas, there was no significant difference in relative expression of Caspase-3 mRNA between groups ( P>0.05). However, with the ursolic acid concentration increasing, the relative expressions of pro-Caspase-3 protein decreased and the relative expressions of activated Caspase-3 increased; there were significant differences between groups ( P<0.05).

Conclusion

Ursolic acid can effectively inhibit the proliferation of osteosarcoma cell line U2-OS, induce the down-regulation of cyclin D1 expression leading to G 0/G 1 phase arrest, increase the activation of Caspase-3 and promote cell apoptosis.

Location of the bioactive pentacyclic triterpene ursolic acid in the membrane. A molecular dynamics study

Ursolic acid (URS), an ursane-representative bioactive pentacyclic triterpene, is a plant secondary metabolite presenting a great number of pharmacological beneficial properties. Due to the prominent hydrophobic character of URS and its high phospholipid/water partition coefficient, some of its possible effects on biological systems might be related to its capacity to interact with and locate into the membrane as well as interact specifically with its components. In this work, we have studied the location and orientation of URS in the membrane by molecular dynamics simulations. At the end of the simulation, URS locates near the surface in vicinity to the phospholipid headgroups but its orientation depends on lipid composition, its final average orientation being a nearly parallel one in POPC but a nearly perpendicular one in POPC/POPE/POPG/PSM/Chol. Furthermore, in the complex lipid system URS seems to interact specifically with POPE, PSM, and Chol excluding POPG from its surroundings, which could lead to phase separation and domain formation. The different disposition of URS in the membrane and its specific interaction with certain lipid types could lead to a significant perturbation of the membrane structure. The important pharmacological activities of URS would rely on the effects it exerts on the membrane structure in general and the existence of specific interactions with specific lipids in particular.

Tianfoshen oral liquid: a CFDA approved clinical traditional Chinese medicine, normalizes major cellular pathways disordered during colorectal carcinogenesis

Colorectal cancer remains the third leading cause of cancer death worldwide, suggesting exploration of novel therapeutic avenues may be useful. In this study, therefore, we determined whether Tianfoshen oral liquid, a Chinese traditional medicine that has been used to treat non-small cell lung cancer, would be therapeutically beneficial for colorectal cancer patients. Our data show that Tianfoshen oral liquid effectively inhibits growth of colorectal cancer cells both in vitro and in vivo. We further employed a comprehensive strategy that included chemoinformatics, bioinformatics and network biology methods to unravel novel insights into the active compounds of Tianfoshen oral liquid and to identify the common therapeutic targets and processes for colorectal cancer treatment. We identified 276 major candidate targets for Tianfoshen oral liquid that are central to colorectal cancer progression. Gene enrichment analysis showed that these targets were associated with cell cycle, apoptosis, cancer-related angiogenesis, and chronic inflammation and related signaling pathways. We also validated experimentally the inhibitory effects of Tianfoshen oral liquid on these pathological processes, both in vitro and in vivo. In addition, we demonstrated that Tianfoshen oral liquid suppressed multiple relevant key players that sustain and promote colorectal cancer, which is suggests the potential therapeutic efficacy of Tianfoshen oral liquid in future colorectal cancer treatments.

The Apoptotic Effect of Ursolic Acid on SK-Hep-1 Cells is Regulated by the PI3K/Akt, p38 and JNK MAPK Signaling Pathways

Ursolic acid (UA) is a pentacyclic triterpene acid that is present in a wide variety of medicinal herbs and edible plants. This study investigated the effect of UA on apoptosis and proliferation of hepatocellular carcinoma SK-Hep-1 cells. After treatment of SK-Hep-1 cells with different concentrations of UA, we observed that cell viability was reduced in a dose- and time-dependent manner. Furthermore, there was a dose-dependent increase in the percentage of cells in the sub-G1 and G2/M phases, with cells treated with 60 μM showing the highest percentages of cells in those phases. UA-induced chromatin condensation of nuclei was observed by using DAPI staining. The western blot results revealed that exposure to UA was associated with decreased expression of the anti-apoptotic proteins Mcl-1, Bcl-xL, Bcl-2, and TCTP and increased expression of apoptosis-related proteins TNF-α, Fas, FADD, Bax, cleaved caspase-3, caspase-8, caspase-9, and PARP. Immunocytochemistry staining showed that treatment with UA resulted in increased expression of caspase-3. Moreover, exposure to UA resulted in the inhibition of the PI3K/Akt and p38 MAPK signaling pathways. These findings suggest that UA inhibits the proliferation of SK-Hep-1 cells and induces apoptosis.

VRK1 phosphorylates and protects NBS1 from ubiquitination and proteasomal degradation in response to DNA damage

NBS1 is an early component in DNA-Damage Response (DDR) that participates in the initiation of the responses aiming to repair double-strand breaks caused by different mechanisms. Early steps in DDR have to react to local alterations in chromatin that are induced by DNA damage. NBS1 participates in the early detection of DNA damage and functions as a platform for the recruitment and assembly of components that are sequentially required for the repair process. In this work we have studied whether the VRK1 chromatin kinase can affect the activation of NBS1 in response to DNA damage induced by ionizing radiation. VRK1 is forming a basal preassembled complex with NBS1 in non-damaged cells. Knockdown of VRK1 resulted in the loss of NBS1 foci induced by ionizing radiation, an effect that was also detected in cell-cycle arrested cells and in ATM (-/-) cells. The phosphorylation of NBS1 in Ser343 by VRK1 is induced by either doxorubicin or IR in ATM (-/-) cells. Phosphorylated NBS1 is also complexed with VRK1. NBS1 phosphorylation by VRK1 cooperates with ATM. This phosphorylation of NBS1 by VRK1 contributes to the stability of NBS1 in ATM (-/-) cells, and the consequence of its loss can be prevented by treatment with the MG132 proteasome inhibitor of RNF8. We conclude that VRK1 regulation of NBS1 contributes to the stability of the repair complex and permits the sequential steps in DDR.