Butein suppresses breast cancer growth by reducing a production of intracellular reactive oxygen species

SIRT1-activating butein inhibits arecoline-induced mitochondrial dysfunction through PGC1α and MTP18 in oral cancer

BACKGROUND

Mitochondrial dysfunction associated with mitochondrial DNA mutations, enzyme defects, generation of ROS, and altered oxidative homeostasis is known to induce oral carcinogenesis during exposure to arecoline. Butein, a natural small molecule from Butea monosperma, possesses anti-inflammatory, anti-diabetic, and anti-cancer effects. However, the role of butein in the mitochondrial quality control mechanism has not been illuminated clearly.

PURPOSE

This study aimed to explore the role of butein in preserving mitochondrial quality control during arecoline-induced mitochondrial dysfunction in oral cancer to curtail the early onset of carcinogenesis.

METHODS

Cell viability was evaluated by MTT assay. The relative protein expressions were determined by western blotting. Immunofluorescence and confocal imaging were used to analyze the relative fluorescence and co-localization of proteins. Respective siRNAs were used to examine the knockdown-based studies.

RESULTS

Butein, in the presence of arecoline, significantly caused a decrease in mitochondrial hyperpolarization and ROS levels in oral cancer cells. Mechanistically, we found an increase in COXIV, TOM20, and PGC1α expression during butein treatment, and inhibition of PGC1α blunted mitochondrial biogenesis and decreased the mitochondrial pool. Moreover, the fission protein MTP18, and its molecular partners DRP1 and MFF were dose-dependently increased during butein treatment to maintain mitochondria mass. In addition, we also found increased expression of various mitophagy proteins, including PINK1, Parkin, and LC3 during butein treatment, suggesting the clearance of damaged mitochondria to maintain a healthy mitochondrial pool. Interestingly, butein increased the activity of SIRT1 to enhance the functional mitochondrial pool, and inhibition of SIRT1 found to reduce the mitochondrial levels, as evident from the decrease in the expression of PGC1α and MTP18 in oral cancer cells.

CONCLUSION

Our study proved that SIRT1 maintains a functional mitochondrial pool through PGC1α and MTP18 for biogenesis and fission of mitochondria during arecoline exposure and could decrease the risk of mitochondria dysfunctionality associated with the onset of oral carcinogenesis.

Butein inhibits oral squamous cell carcinoma growth via promoting MCL-1 ubiquitination

Oral squamous cell carcinoma (OSCC) is the most common malignant head and neck carcinoma type. Myeloid cell leukemia-1 (MCL-1), an anti-apoptotic BCL-1 protein, has been verified to be among the most highly upregulated pathologic proteins in human cancers linked to tumor relapse, poor prognosis and therapeutic resistance. Herein, therapeutic targeting MCL-1 is an attractive focus for cancer treatment. The present study found that butein, a potential phytochemical compound, exerted profound antitumor effects on OSCC cells. Butein treatment significantly inhibited cell viability, proliferation capacity and colony formation ability, and activated cell apoptotic process. Further potential mechanism investigation showed that promoting MCL-1 ubiquitination and degradation is the major reason for butein-mediated OSCC cell cytotoxicity. Our results uncovered that butein could facilitate E3 ligase FBW7 combined with MCL-1, which contributed to an increase in the ubiquitination of MCL-1 Ub-K48 and degradation. The results of both in vitro cell experiments and in vivo xenograft models imply a critical antitumor function of butein with the well-tolerated feature, and it might be an attractive and promising agent for OSCC treatment.

Progress in discovery and development of natural inhibitors of histone deacetylases (HDACs) as anti-cancer agents

The study of epigenetic translational modifications had drawn great interest for the last few decades. These processes play a vital role in many diseases and cancer is one of them. Histone acetyltransferase (HAT) and histone deacetylases (HDACs) are key enzymes involved in the acetylation and deacetylation of histones and ultimately in post-translational modifications. Cancer frequently exhibits epigenetic changes, particularly disruption in the expression and activity of HDACs. It includes the capacity to regulate proliferative signalling, circumvent growth inhibitors, escape cell death, enable replicative immortality, promote angiogenesis, stimulate invasion and metastasis, prevent immunological destruction, and genomic instability. The majority of tumours develop and spread as a result of HDAC dysregulation. As a result, HDAC inhibitors (HDACis) were developed, and they today stand as a very promising therapeutic approach. One of the most well-known and efficient therapies for practically all cancer types is chemotherapy. However, the efficiency and safety of treatment are constrained by higher toxicity. The same has been observed with the synthetic HDACi. Natural products, owing to many advantages over synthetic compounds for cancer treatment have always been a choice for therapy. Hence, naturally available molecules are of particular interest for HDAC inhibition and HDAC has drawn the attention of the research fraternity due to their potential to offer a diverse array of chemical structures and bioactive compounds. This diversity opens up new avenues for exploring less toxic HDAC inhibitors to reduce side effects associated with conventional synthetic inhibitors. The review presents comprehensive details on natural product HDACi, their mechanism of action and their biological effects. Moreover, this review provides a brief discussion on the structure activity relationship of selected natural HDAC inhibitors and their analogues which can guide future research to discover selective, more potent HDACi with minimal toxicity.

Potent Antioxidant and Anti-Tyrosinase Activity of Butein and Homobutein Probed by Molecular Kinetic and Mechanistic Studies

Butein (BU) and homobutein (HB) are bioactive polyhydroxylated chalcones widespread in dietary plants, whose antioxidant properties require mechanistic definition. They were investigated by inhibited autoxidation kinetic studies of methyl linoleate in Triton™ X-100 micelles at pH 7.4, 37 °C. Butein had kinh = (3.0 ± 0.9) × 104 M-1s-1 showing a chain-breaking mechanism with higher antioxidant activity than reference α-tocopherol (kinh = (2.2 ± 0.6) × 104 M-1s-1), particularly concerning the stoichiometry or peroxyl radical trapping n = 3.7 ± 1.1 vs. 2.0 for tocopherol. Homobutein had kinh = (2.8 ± 0.9) × 103 M-1s-1, pairing the relative BDEOH measured by radical equilibration EPR as 78.4 ± 0.2 kcal/mol for BU and estimated as 82.6 kcal/mol for HB. The inhibition of mushroom tyrosinase (mTYR) by HB and BU was also investigated. BU gives a reversible uncompetitive inhibition of monophenolase reaction with KI' = 9.95 ± 2.69 µM and mixed-type diphenolase inhibition with KI = 3.30 ± 0.75 µM and KI' = 18.75 ± 5.15 µM, while HB was nearly competitive toward both mono- and diphenolase with respective KI of 2.76 ± 0.70 µM and 2.50 ± 1.56 µM. IC50 values (monophenolase/diphenolase at 1 mM substrate) were 10.88 ± 2.19 µM/15.20 ± 1.25 µM, 14.78 ± 1.05 µM/12.36 ± 2.00 µM, and 33.14 ± 5.03 µM/18.27 ± 3.42 µM, respectively, for BU, HB, and reference kojic acid. Molecular docking studies confirmed the mechanism. Results indicate very potent antioxidant activity for BU and potent anti-tyrosinase activity for both chalcones, which is discussed in relation to bioactivity toward protection from skin disorders and food oxidative spoilage.

Design, Synthesis, and Evaluation of Novel Indole Hybrid Chalcones and Their Antiproliferative and Antioxidant Activity

The synthesis, anticancer, and antioxidant activities of a series of indole-derived hybrid chalcones are reported here. First, using the well-known Claisen-Schmidt condensation method, a set of 29 chalcones has been designed, synthesized, and consequently characterized. Subsequently, screening for the antiproliferative activity of the synthesized hybrid chalcones was performed on five cancer cell lines (HCT116, HeLa, Jurkat, MDA-MB-231, and MCF7) and two non-cancer cell lines (MCF-10A and Bj-5ta). Chalcone 18c, bearing 1-methoxyindole and catechol structural features, exhibited selective activity against cancer cell lines with IC50 values of 8.0 ± 1.4 µM (Jurkat) and 18.2 ± 2.9 µM (HCT116) and showed no toxicity to non-cancer cells. Furthermore, antioxidant activity was evaluated using three different methods. The in vitro studies of radical scavenging activity utilizing DPPH radicals as well as the FRAP method demonstrated the strong activity of catechol derivatives 18a-c. According to the ABTS radical scavenging assay, the 3-methoxy-4-hydroxy-substituted chalcones 19a-c were slightly more favorable. In general, a series of 3,4-dihydroxychalcone derivatives showed properties as a lead compound for both antioxidant and antiproliferative activity.

Anticancer Potential of Natural Chalcones: In Vitro and In Vivo Evidence

There is no doubt that significant progress has been made in tumor therapy in the past decades. However, the discovery of new molecules with potential antitumor properties still remains one of the most significant challenges in the field of anticancer therapy. Nature, especially plants, is a rich source of phytochemicals with pleiotropic biological activities. Among a plethora of phytochemicals, chalcones, the bioprecursors of flavonoid and isoflavonoids synthesis in higher plants, have attracted attention due to the broad spectrum of biological activities with potential clinical applications. Regarding the antiproliferative and anticancer effects of chalcones, multiple mechanisms of action including cell cycle arrest, induction of different forms of cell death and modulation of various signaling pathways have been documented. This review summarizes current knowledge related to mechanisms of antiproliferative and anticancer effects of natural chalcones in different types of malignancies including breast cancers, cancers of the gastrointestinal tract, lung cancers, renal and bladder cancers, and melanoma.

Explicit molecular dynamics simulation studies to discover novel natural compound analogues as Mycobacterium tuberculosis inhibitors

Tuberculosis (TB) in one of the dreadful diseases present globally. This is caused by Mycobacterium tuberculosis. Mycobacterium tuberculosis dethiobiotin synthetase (MtDTBS) is an essential enzyme in biotin biosynthesis and is an ideal target to design and develop novel inhibitors. In order to effectively combat this disease six natural compound (butein) analogues were subjected to molecular docking to determine their binding mode and the binding affinities. The resultant complex structures were subjected to 500 ns simulation run to estimate their binding stabilities using GROMACS. The molecular dynamics simulation studies provided essential evidence that the systems were stable during the progression of 500 ns simulation run. The root mean square deviation (RMSD) of all the systems was found to be below 0.3 nm stating that the systems are well converged. The radius of gyration (Rg) profiles indicated that the systems were highly compact without any major fluctuations. The principle component analysis (PCA) and Gibbs energy landscape studies have revealed that the comp3, comp5 and comp11 systems navigated marginally through the PC2. The intermolecular interactions have further demonstrated that all the compounds have displayed key residue interactions, firmly holding the ligands at the binding pocket. The residue Lys37 was found consistently to interact with all the ligands highlighting its potential role in inhibiting the MtDTBS. Our investigation further put forth two novel compounds (comp10 and comp11) as putative antituberculosis agents. Collectively, we propose six compounds has plausible inhibitors to curtail TB and further can act as scaffolds in designing new compounds.

Chalcones: Potential Chemotherapeutic Compounds and Educational Tools for Closing the Loop in STEM

ConspectusThe study discussed herein describes the synthesis of halogenated chalcones as potential chemotherapeutics. The synthesis work was conducted by undergraduate students participating in an Organic Chemistry II laboratory course at Tuskegee University, while the biological assays were conducted by students enrolled in a Molecular Biology I laboratory course. Chalcones were synthesized via aldol condensation and purified from hot ethanol. The impetus for the work was the fact that Tuskegee University sits positioned within the Black Belt of Alabama which, in addition to being an area of fertile soil and excellent farmland, is also an area rife with health disparities that particularly affect African-Americans. Breast cancer, specifically triple-negative breast cancer, affects African-American women at a higher rate than any other ethnic group. The work described herein addresses a practical problem [teaching undergraduate students about the interface of synthetic techniques, synthesis of specific classes of compounds, functional groups, and their relation to biological activity], as well an existential problem [the prevalence of breast cancer among African-American women, and the need to develop targeted treatments]. One of the chief aims of this approach of integrating these ideas into our laboratory courses was to facilitate the understanding of translational science, i.e. taking chalcones from benchtop to potential therapies for breast cancer. Another aim of the current approach was to, in essence, create a research problem based course and concomitantly use the results of the experiments performed in the course as a way to address the dearth of research funding that HBCUs typically receive. The pharmacological activities of chalcones and their derivatives are well documented. They are an important class of natural products that occur in edible plant derivatives such as spices, teas, fruits and various vegetables. In vitro studies have shown that chalcones inhibit proliferation of breast cancer cells by inducing apoptosis and blocking cell progression. The synthesis of chalcones with aromatic substituents has been investigated, and electron rich chalcones, i.e., chalcones with donors attached to the aromatic rings, have been studied extensively. The effect that adding electron withdrawing groups to the chalcone structural motif has on the antiproliferation ability of chalcones had been only minimally investigated at the time that our studies were being conducted. We examined the introduction of chlorine to the aromatic system of the chalcone and how these electron withdrawing substituents affect the chalcone's antiproliferative ability. It was discovered that (E)-3-(4-chlorophenyl)-1-phenylprop-2-en-1-one inhibited MDA-MB-231 cell progression in a dose dependent manner and outperformed the unsubstituted (E)-1,3-diphenyl-2-propen-1-one (1) at concentrations ranging from 0 μg/mL to 20 μg/mL. Cell death was determined by MTT assay.

Butein Ameliorates Oxidative Stress in H9c2 Cardiomyoblasts through Activation of the NRF2 Signaling Pathway

Oxidative stress, defined as an imbalance between reactive oxygen species (ROS) production and the antioxidant defense system, contributes to the pathogenesis of many heart diseases. Therefore, oxidative stress has been highlighted as a therapeutic target for heart disease treatment. Butein, a tetrahydroxychalcone, has potential biological activities, especially antioxidant properties. However, the effect of butein on oxidative-stressed heart cells has been poorly studied. Thus, we sought to identify the antioxidant effects of butein in H9c2 cardiomyoblasts. To elucidate these antioxidant effects, various concentrations of butein were used to pretreat H9c2 cells prior to H₂O₂ treatment. Thereafter, measures of oxidative damages, such as ROS production, antioxidant expression levels, and apoptosis, were evaluated. Butein effectively increased cell viability and rescued the cells from oxidative damage through the inhibition of ROS production, apoptosis, and increased antioxidant expression. Furthermore, butein dramatically inhibited mitochondrial dysfunction and endoplasmic reticulum (ER) stress, which are the main ROS inducers. Nrf2 protein translocated from the cytosol to the nucleus and consequently activated its target genes as oxidative stress suppressors. These findings demonstrate that butein has potential antioxidant effects in H9c2 cardiomyoblasts, suggesting that it could be used as a therapeutic substance for the treatment of cardiac diseases.

Dihydroconiferyl Ferulate Isolated from Dendropanax morbiferus H.Lév. Suppresses Stemness of Breast Cancer Cells via Nuclear EGFR/c-Myc Signaling

Breast cancer is the leading cause of global cancer incidence and breast cancer stem cells (BCSCs) have been identified as the target to overcome breast cancer in patients. In this study, we purified a BCSC inhibitor from Dendropanax morbiferus H.Lév. leaves through several open column and high-performance liquid chromatography via activity-based purification. The purified cancer stem cell (CSC) inhibitor was identified as dihydroconiferyl ferulate using nuclear magnetic resonance and mass spectrometry. Dihydroconiferyl ferulate inhibited the proliferation and mammosphere formation of breast cancer cells and reduced the population of CD44^high/CD24^low cells. Dihydroconiferyl ferulate also induced apoptosis, inhibited the growth of mammospheres and reduced the level of total and nuclear EGFR protein. It suppressed the EGFR levels, the interaction of Stat3 with EGFR, and c-Myc protein levels. Our findings show that dihydroconiferyl ferulate reduced the level of nuclear epidermal growth factor receptor (EGFR) and induced apoptosis of BCSCs through nEGFR/Stat3-dependent c-Myc deregulation. Dihydroconiferyl ferulate exhibits potential as an anti-CSC agent through nEGFR/Stat3/c-Myc signaling.

The Biphasic Effect of Flavonoids on Oxidative Stress and Cell Proliferation in Breast Cancer Cells

Flavonoids have been reported to play an essential role in modulating processes of cellular redox homeostasis such as scavenging ROS. Meanwhile, they also induce oxidative stress that exerts potent antitumor bioactivity. However, the contradiction between these two aspects still remains unclear. In this study, four typical flavonoids were selected and studied. The results showed that low-dose flavonoids slightly promoted the proliferation of breast cancer cells under normal growth via gradually reducing accumulated oxidative products and demonstrated a synergistic effect with reductants NAC or VC. Besides, low-dose flavonoids significantly reduced the content of ROS and MDA induced by LPS or Rosup but restored the activity of SOD. However, high-dose flavonoids markedly triggered the cell death via oxidative stress as evidenced by upregulated ROS, MDA and downregulated SOD activity that could be partly rescued by NAC pretreatment, which was also confirmed by antioxidative gene expression levels. The underlying mechanism of such induced cell death was pinpointed as apoptosis, cell cycle arrest, accumulated mitochondrial superoxide, impaired mitochondrial function and decreased ATP synthesis. Transcriptomic analysis of apigenin and quercetin uncovered that high-dose flavonoids activated TNF-α signaling, as verified through detecting inflammatory gene levels in breast cancer cells and RAW 264.7 macrophages. Moreover, we identified that BRCA1 overexpression effectively attenuated such oxidative stress, inflammation and inhibited ATP synthesis induced by LPS or high dose of flavonoids possibly through repairing DNA damage, revealing an indispensable biological function of BRCA1 in resisting oxidative damage and inflammatory stimulation caused by exogenous factors.

Butein and Frondoside-A Combination Exhibits Additive Anti-Cancer Effects on Tumor Cell Viability, Colony Growth, and Invasion and Synergism on Endothelial Cell Migration

Despite the significant advances in targeted- and immuno-therapies, lung and breast cancer are at the top list of cancer incidence and mortality worldwide as of 2020. Combination therapy consisting of a mixture of different drugs taken at once is currently the main approach in cancer management. Natural compounds are extensively investigated for their promising anti-cancer potential. This study explored the anti-cancer potential of butein, a biologically active flavonoid, on two major solid tumors, namely, A549 lung and MDA-MB-231 breast cancer cells alone and in combination with another natural anti-cancer compound, frondoside-A. We demonstrated that butein decreases A549 and MDA-MB-231 cancer cell viability and colony growth in vitro in addition to tumor growth on chick embryo chorioallantoic membrane (CAM) in vivo without inducing any noticeable toxicity. Additionally, non-toxic concentrations of butein significantly reduced the migration and invasion of both cell lines, suggesting its potential anti-metastatic effect. We showed that butein anti-cancer effects are due, at least in part, to a potent inhibition of STAT3 phosphorylation, leading to PARP cleavage and consequently cell death. Moreover, we demonstrated that combining butein with frondoside-A leads to additive effects on inhibiting A549 and MDA-MB-231 cellular viability, induction of caspase 3/7 activity, inhibition of colony growth, and inhibition of cellular migration and invasion. This combination reached a synergistic effect on the inhibition of HUVECs migration in vitro. Collectively, this study provides sufficient rationale to further carry out animal studies to confirm the relevance of these compounds’ combination in cancer therapy.

Molecular mechanisms underlying chemopreventive potential of butein: Current trends and future perspectives

Despite extensive efforts, cancer is still often considered as an incurable disease and initiation of novel drug development programs is crucial to improve the prognosis and clinical outcome of patients. One of the major approaches in designing the novel cancer drugs has historically comprised studies of natural agents with diverse anticancer properties. As only a marginal part of natural compounds has been investigated, this approach still represents an attractive source of new potential antitumor molecules. In this review article, different anticancer effects of plant-derived chalcone, butein, are discussed, including its growth inhibitory action, proapoptotic, antiangiogenic and antimetastatic activities in a variety of cancer cells. The molecular mechanisms underlying these effects are presented in detail, revealing interactions of butein with multiple cellular targets (Bcl-2/Bax, caspases, STAT3, cyclins, NF-κB, COX-2, MMP-9, VEGF/R etc.) and regulation of a wide range of intracellular signal transduction pathways. These data altogether allow a good basis for initiating further in vivo studies as well as clinical trials. Along with the efforts to overcome low bioavailability issues generally characteristic to plant metabolites, butein can be considered as a potential lead compound for safe and more efficient cancer drugs in the future.

Naturally occurring heterocyclic anticancer compounds

Naturally occurring heterocyclic scaffolds are key ingredients for the development of various therapeutics employed for biomedical applications. Heterocyclic pharmacophores are widely disseminated and have been befallen in almost all categories of drugs for the alleviation of myriad ailments including diabetes, neurodegenerative, psychiatric, microbial infections, disastrous cancers etc. Countless fused heterocyclic anticancerous templates are reported to display antimetabolite, antioxidant, antiproliferative, cytostatic etc. pharmacological actions via targeting different signaling pathways (cell cycle, PI-3kinase/Akt, p53, caspase extrinsic pathway etc.), overexpressive receptors (EGRF, HER2, EGF, VEGF etc.) and physiological enzymes (topoisomerase I and II, cyclin dependent kinase etc.). A compiled description on various natural sources (plants, microbes, marine) containing anticancer agents comprising heterocyclic ring specified with presence of nitrogen (vincristine, vinblastine, indole-3-carbinol, meridianins, piperine, lamellarins etc.), oxygen (paclitaxel, halichondrin B, quercetin, myricetin, kaempferol etc.) and sulphur atoms (brugine, fucoidan, carrageenan etc.) are displayed here along with their molecular level cytotoxic action and therapeutic applications.

Novel Butein Derivatives Repress DDX3 Expression by Inhibiting PI3K/AKT Signaling Pathway in MCF-7 and MDA-MB-231 Cell Lines

Background

Breast cancer is one of the major causes of mortalities noticed in women globally. DDX3 has emerged as a potent target for several cancers, including breast cancer to which currently there are no reported or approved drugs.

Methods

To find effective cancer therapeutics, three compounds were computationally designed tweaking the structure of natural compound butein. These compounds were synthesized and evaluated for their anticancer property in MCF-7 and MDA-MB-231 cell lines targeting DDX3. The in silico molecular docking studies have shown that the compounds have occupied the binding site of the human DDX3 target. Furthermore, to investigate the cell viability effect of 3a, 3b, and 3c on MCF-7 and MDA-MB-231 cell lines, the cell lines were treated with different concentrations of compounds for 24 and 48 h and measured using MTT assay.

Results

The cell viability results showed that the have induced dose dependent suppression of DDX3 expression. Additionally, 3b and 3c have reduced the expression of DDX3 in MCF-7 and MDA-MD-231 cell lines. 3b or 3c treated cell lines increased apoptotic protein expression. Both the compounds have induced the apoptotic cell death by elevated levels of cleaved PARP and cleaved caspase 3 and repression of the anti-apoptosis protein BCL-xL. Additionally, they have demonstrated the G2/M phase cell cycle arrest in both the cell lines. Additionally, 3c decreased PI3K and AKT levels.

Conclusions

Our results shed light on the anticancer ability of the designed compounds. These compounds can be employed as chemical spaces to design new prospective drug candidates. Additionally, our computational method can be adapted to design new chemical scaffolds as plausible inhibitors.

Butein combined with radiotherapy enhances radioresponse of gastric cancer cell by impairing DNA damage repair

Radiation therapy is common in the current procedures of cancer treatment, but in many cases, radiation resistance of cancerous tissue limits efficacy in clinical applications. Therefore, the use of radiosensitizers has been introduced as an effective strategy to increase the efficiency of radiotherapy. Butein (2', 3, 4, 4'-Tetrahydroxychalcone), a polyphenolic compound of flavonoids family, presents anti-cancer properties and inhibits the signaling pathways associated with radiation resistance. Therefore, we hypothesized that butein in combination with radiation may increase radiosensitivity. To evaluate the radiosensitizing effect of butein, we used MKN-45 cell line and performed several assays such as MTT, soft-agar colony formation, apoptosis, cell cycle, and comet assays. Based on obtained results, butein significantly enhanced radiosensitivity of MKN-45 cells. Butein treatment abrogated the radiation-induced G2/M cell cycle arrest, increased DNA damage, enhanced apoptosis, and reduced colony-forming ability of irradiated cells. This study on MKN-45 cells demonstrates that combination of butein with radiotherapy increases its radiosensitivity by abrogating the radiation-induced G2/M blockage, impairing DNA repair, and enhancing apoptotic and reproductive cell death. Therefore, we suggest butein as a candidate for combination with radiation therapy to decrease dose of radiation delivered to the patients and its corresponding side effects.

Naringenin inhibits migration, invasion, induces apoptosis in human lung cancer cells and arrests tumour progression in vitro

Lung cancer is one of the major cause for high-death rate all over the world, due to increased metastasize and difficulties in diagnosis. Naringenin is naturally occurring flavonoid found in various fruits including tomatoes, citrus fruit and figs. Naringenin is known to have several therapeutic effects including anti-atherogenic, antimicrobial, anti-inflammatory, hepatoprotective, anticancer and anti-mutagenic. The present study was aimed to analyse the naringenin induced anti-proliferative and apoptosis effects in human lung cancer cells. Cells were treated with various concentrations of naringenin (10, 100 & 200 µmol/L) for 48 hours. Cisplatin (20 µg/mL) was used as positive control. Cell viability, apoptosis, migration and mRNA, and protein expression of caspase-3, matrixmetallo proteinases-2 (MMP-2) and MMP-9 were determined. The cell viability was 93.7 ± 7.5, 51.4 ± 4.4 and 32.1 ± 2.1 at 10, 100 and 200 µmol/L of naringenin respectively. Naringenin significantly increased apoptotic cells. The 100 and 200 µmol/L of naringenin significantly suppressed the larger wounds of cultured human cancer cells compared with the untreated lung cancer cells. Naringenin increased d the expression of caspase-3 and reduced the expression of MMP-2 and MMP-9. Taking all these data together, it is suggested that the naringenin was effective against human lung cancer proliferation, migration and metastasis.

Naringenin inhibits migration, invasion, induces apoptosis in human lung cancer cells and arrests tumour progression in vitro

Lung cancer is one of the major cause for high-death rate all over the world, due to increased metastasize and difficulties in diagnosis. Naringenin is naturally occurring flavonoid found in various fruits including tomatoes, citrus fruit and figs. Naringenin is known to have several therapeutic effects including anti-atherogenic, antimicrobial, anti-inflammatory, hepatoprotective, anticancer and anti-mutagenic. The present study was aimed to analyse the naringenin induced anti-proliferative and apoptosis effects in human lung cancer cells. Cells were treated with various concentrations of naringenin (10, 100 & 200 µmol/L) for 48 hours. Cisplatin (20 µg/mL) was used as positive control. Cell viability, apoptosis, migration and mRNA, and protein expression of caspase-3, matrixmetallo proteinases-2 (MMP-2) and MMP-9 were determined. The cell viability was 93.7 ± 7.5, 51.4 ± 4.4 and 32.1 ± 2.1 at 10, 100 and 200 µmol/L of naringenin respectively. Naringenin significantly increased apoptotic cells. The 100 and 200 µmol/L of naringenin significantly suppressed the larger wounds of cultured human cancer cells compared with the untreated lung cancer cells. Naringenin increased d the expression of caspase-3 and reduced the expression of MMP-2 and MMP-9. Taking all these data together, it is suggested that the naringenin was effective against human lung cancer proliferation, migration and metastasis.

ERα is a target for butein-induced growth suppression in breast cancer

Breast cancer (BCa) has the highest incidence and mortality among malignant diseases in female worldwide. BCa is frequently caused by estrogen receptor α (ERα), a ligand-dependent receptor that highly expressed in about 70% of breast tumors. Therefore, ERα has become a well-characterized and the most effective target for treating ERα-expressing BCa (ERα⁺ BCa). However, the acquire resistance was somehow developed in patients who received current ERα signaling-targeted endocrine therapies. Hence, discovery of novel anti-estrogen/ERα strategies is urgent. In the present study, we identified butein as a potential agent for breast cancer treatment by the use of a natural product library. We showed that butein inhibits the growth of ERα⁺ BCa both in vitro and in vivo which is associated with cell cycle arrest that partially triggered by butein-induced ERα downregulation. Mechanically, butein binds to a specific pocket of ERα and promotes proteasome-mediated degradation of the receptor. Collectively, this work reveals that butein is a candidate to diminish ERα signaling which represents a potentially novel strategy for treating BCa.

MCF7 Spheroid Development: New Insight about Spatio/Temporal Arrangements of TNTs, Amyloid Fibrils, Cell Connections, and Cellular Bridges

Human breast adenocarcinoma cells (MCF7) grow in three-dimensional culture as spheroids that represent the structural complexity of avascular tumors. Therefore, spheroids offer a powerful tool for studying cancer development, aggressiveness, and drug resistance. Notwithstanding the large amount of data regarding the formation of MCF7 spheroids, a detailed description of the morpho-functional changes during their aggregation and maturation is still lacking. In this study, in addition to the already established role of gap junctions, we show evidence of tunneling nanotube (TNT) formation, amyloid fibril production, and opening of large stable cellular bridges, thus reporting the sequential events leading to MCF7 spheroid formation. The variation in cell phenotypes, sustained by dynamic expression of multiple proteins, leads to complex networking among cells similar to the sequence of morphogenetic steps occurring in embryogenesis/organogenesis. On the basis of the observation that early events in spheroid formation are strictly linked to the redox homeostasis, which in turn regulate amyloidogenesis, we show that the administration of N-acetyl-l-cysteine (NAC), a reactive oxygen species (ROS) scavenger that reduces the capability of cells to produce amyloid fibrils, significantly affects their ability to aggregate. Moreover, cells aggregation events, which exploit the intrinsic adhesiveness of amyloid fibrils, significantly decrease following the administration during the early aggregation phase of neutral endopeptidase (NEP), an amyloid degrading enzyme.

Molecular and cellular basis of the anticancer activity of the prenylated flavonoid icaritin in hepatocellular carcinoma

The prenylated flavonoid icaritin (ICT) is currently undergoing phase 3 clinical trial for the treatment of advanced hepatocellular carcinoma (HCC), based on a solid array of preclinical and clinical data. The antitumor activity originates from the capacity of the drug to modulate several signaling effectors in cancer cells, mainly the estrogen receptor splice variant ERα36, the transcription factors STAT3 and NFκB, and the chemokine receptor CXCR4. Recent studies have implicated additional components, including different microRNAs, the generation of reactive oxygen species and the targeting of sphingosine kinase-1. ICT also engages the RAGE-HMGB1 signaling route and modulates the apoptosis/autophagy crosstalk to promote its anticancer activity. In addition, ICT exerts profound changes on the tumor microenvironment to favor an immune-response. Collectively, these multiple biochemical and cellular characteristics confer to ICT a robust activity profile which can be exploited to treat HCC, as well as other cancers, including glioblastoma and onco-hematological diseases such as chronic myeloid leukemia. This review provides an update of the pharmacological properties of ICT and its metabolic characteristics. It also addresses the design of derivatives, including both natural products and synthetic molecules, such as SNG1153 also in clinical trial. The prenylated flavonoid ICT deserves attention as a multifunctional natural product potentially useful to improve the treatment of advanced hepatocellular carcinoma.

The inhibitory effects of butein on cell proliferation and TNF-α-induced CCL2 release in racially different triple negative breast cancer cells

Drug resistance is the leading cause of breast cancer-related mortality in women, and triple negative breast cancer (TNBC) is the most aggressive subtype, affecting African American women more aggressively compared to Caucasians women. Of all cancer-related deaths, 15 to 20% are associated with inflammation, where proinflammatory cytokines have been implicated in the tumorigenesis process. The current study investigated the effects of the polyphenolic compound butein (2',3,4,4'-tetrahydroxychalcone) on cell proliferation and survival, as well as its modulatory effect on the release of proinflammatory cytokines in MDA-MB-231 (Caucasian) and MDA-MB-468 (African American) TNBC cell. The results obtained showed that butein decreased cell viability in a time and dose-dependent manner, and after 72-h of treatment, the cell proliferation rate was reduced in both cell lines. In addition, butein was found to have higher potency in MDA-MB-468, exhibiting anti-proliferative effects in lower concentrations. Apoptosis assays demonstrated that butein (50 μM) increased apoptotic cells in MDA MB-468, showing 60% of the analyzed cells in the apoptotic phase, compared to 20% in MDA-MB-231 cells. Additionally, butein downregulated both protein and mRNA expression of the proinflammatory cytokine, CCL2, and IKBKE in TNFα-activated Caucasian cells, but not in African Americans. This study demonstrates butein potential in cancer cell suppression showing a higher cytotoxic, anti-proliferative, and apoptotic effects in African Americans, compared to Caucasians TNBC cells. It also reveals the butein inhibitory effect on CCL2 expression with a possible association with IKBKE downregulation in MDA-MB-231 cells only, indicating that Caucasians and African Americans TNBC cells respond differently to butein treatment. The obtained findings may provide an explanation regarding the poor therapeutic response in African American patients with advanced TNBC.

The sirtuin family in cancer

Sirtuins are a family of protein deacylases and ADP-ribosyl-transferases, homologs to the yeast SIR2 protein. Seven sirtuin paralogs have been described in mammals, with different subcellular locations, targets, enzymatic activities, and regulatory mechanisms. All sirtuins share NAD+ as substrate, placing them as central metabolic hubs with strong relevance in lifespan, metabolism, and cancer development. Much effort has been devoted to studying the roles of sirtuins in cancer, providing a wealth of data on sirtuins roles in mouse models and humans. Also, extensive data are available on the effects of pharmacological modulation of sirtuins in cancer development. Here, we present a comprehensive and organized resume of all the existing evidence linking every sirtuin with cancer development. From our analysis, we conclude that sirtuin modulation after tumor initiation results in unpredictable outcomes in most tumor types. On the contrary, all genetic and pharmacological models indicate that sirtuins activation prior to tumor initiation can constitute a powerful preventive strategy.

PERK/eIF-2α/CHOP Pathway Dependent ROS Generation Mediates Butein-induced Non-small-cell Lung Cancer Apoptosis and G2/M Phase Arrest

Butein, a member of the chalcone family, is a potent anticarcinogen against multiple cancers, but its specific anti-NSCLC mechanism remains unknown. The present study examined the effects of butein treatment on NSCLC cell lines and NSCLC xenografts. Butein markedly decreased NSCLC cell viability; inhibited cell adhesion, migration, invasion, and colony forming ability; and induced cell apoptosis and G2/M phase arrest in NSCLC cells. Moreover, butein significantly inhibited PC-9 xenograft growth. Both in vivo and in vitro studies verified that butein exerted anti-NSCLC effect through activating endoplasmic reticulum (ER) stress-dependent reactive oxygen species (ROS) generation. These pro-apoptotic effects were reversed by the use of 4- phenylbutyric acid (4-PBA), CHOP siRNA, N-acetyl-L-cysteine (NAC) and Z-VAD-FMK (z-VAD) in vitro. Moreover, inhibition of ER stress markedly reduced ROS generation. In addition, in vivo studies further confirmed that inhibition of ER stress or oxidative stress partially abolished the butein-induced inhibition of tumor growth. Therefore, butein is a potential therapeutic agent for NSCLC, and its anticarcinogenic action might be mediated by ER stress-dependent ROS generation and the apoptosis pathway.

Flavonoids: New Frontier for Immuno-Regulation and Breast Cancer Control

Breast cancer (BC) remains the second most common cause of cancer-related deaths in women in the US, despite advances in detection and treatment. In addition, breast cancer survivors often struggle with long-term treatment related comorbidities. Identifying novel therapies that are effective while minimizing toxicity is critical in curtailing this disease. Flavonoids, a subclass of plant polyphenols, are emerging as promising treatment options for the prevention and treatment of breast cancer. Recent evidence suggests that in addition to anti-oxidant properties, flavonoids can directly interact with proteins, making them ideal small molecules for the modulation of enzymes, transcription factors and cell surface receptors. Of particular interest is the ability of flavonoids to modulate the tumor associated macrophage function. However, clinical applications of flavonoids in cancer trials are limited. Epidemiological and smaller clinical studies have been largely hypothesis generating. Future research should aim at addressing known challenges with a broader use of preclinical models and investigating enhanced dose-delivery systems that can overcome limited bioavailability of dietary flavonoids. In this review, we discuss the structure-functional impact of flavonoids and their action on breast tumor cells and the tumor microenvironment, with an emphasis on their clinical role in the prevention and treatment of breast cancer.

Development of near-infrared region luminescent N-acetyl-L-cysteine-coated Ag2S quantum dots with differential therapeutic effect

AIM

N-acetyl-L-cysteine (NAC) is a free radical scavenger. We developed NAC-coated Ag₂S (NAC-Ag₂S) quantum dot (QD) as an optical imaging and therapeutic agent.

MATERIALS & METHODS

QDs were synthesized in water. Their optical imaging potential and toxicity were studied in vitro.

RESULTS

NAC-Ag₂S QDs have strong emission, that is tunable between 748 and 840 nm, and are stable in biologically relevant media. QDs showed significant differences both in cell internalization and toxicity in vitro. QDs were quite toxic to breast and cervical cancer cells but not to lung derived cells despite the higher uptake. NAC-Ag₂S reduces reactive oxygen species (ROS) but causes cell death via DNA damage and apoptosis.

CONCLUSION

NAC-Ag₂S QDs are stable and strong signal-generating theranostic agents offering selective therapeutic effects.

Targeting triple negative breast cancer heterogeneity with chalcones: a molecular insight

Triple negative breast cancers (TNBCs) are aggressive heterogeneous cancers with not yet determined conventional targeted medication. Therefore, identification of new alternatives or improved treatment options to combat this deadly disease is highly needed. On the other hand, various derived products with chalcone scaffold were historically considered excellent candidates for the development of anticancer drugs. Chalcones unique chemical structure and their substantial biological activities in cancer cells make them an extremely attractive target for the treatment of several human carcinomas including TNBCs. This review highlights the promising therapeutic role of chalcones in TNBC management.

Leukemia therapy by flavonoids: Future and involved mechanisms

Flavonoids are a varied family of phytonutrients (plant chemicals) usually are detected in fruits and vegetables. In this big family, there exist more than 10,000 members that is separated into six chief subtypes: isoflavonols, flavonoenes, flavones, flavonols, anthocyanins, and chalcones. The natural compounds, such as fruits, have visible positive effects in regulating of survival involved signaling pathways that performance as the regulator of cell survival, growth, and proliferation. Researchers have established that commonly consumption up flavonoids decreases incidence and development risk of certain cancers, especially leukemia. Flavonoids have been able to induce apoptosis and stimulate cell cycle arrest in cancer cells via different pathways. Similarly, they have antiangiogenesis and antimetastasis capability, which were shown in wide ranges of cancer cells, particularly, leukemia. It seems that flavonoid because of their widespread approval, evident safety and low rate of side effects, have hopeful anticarcinogenic potential for leukemia therapy. Based on the last decade reports, the most important acting mechanisms of these natural compounds in leukemia cells are stimulating of apoptosis pathways by upregulation of caspase 3, 8, 9 and poly ADP-ribose polymerase (PARP) and proapoptotic proteins, particularly Bax activation. As well, they can induce cell cycle arrest in target cells not only via increasing of activated levels of p21 and p53 but also by inhibition of cyclins and cyclin-dependent kinases. Furthermore, attenuation of neclear factor-κB and signal transducer and activator of transcription 3 activation, suppression of signaling pathway and downregulation of intracellular antiapoptotic proteins are other significant antileukemic function mechanism of flavonoids. Overall, it appears that flavonoids are promising and effective compounds in the field of leukemia therapy. In this review, we tried to accumulate and revise most promising flavonoids and finally declared their major working mechanisms in leukemia cells.

New Insights into the Role of Endoplasmic Reticulum Stress in Breast Cancer Metastasis

Cellular stress severely disrupts endoplasmic reticulum (ER) function, leading to the abnormal accumulation of unfolded or misfolded proteins in the ER and subsequent development of endoplasmic reticulum stress (ERS). To accommodate the occurrence of ERS, cells have evolved a highly conserved, self-protecting signal transduction pathway called the unfolded protein response. Notably, ERS signaling is involved in the development of a variety of diseases and is closely related to tumor development, particularly in breast cancer. This review discusses recent research regarding associations between ERS and tumor metastasis. The information presented here will help researchers elucidate the precise mechanisms underlying ERS-mediated tumor metastasis and provide new directions for tumor therapies.

Manilkara zapota (L.) P. Royen Leaf Water Extract Induces Apoptosis in Human Hepatocellular Carcinoma (HepG2) Cells via ERK1/2/Akt1/JNK1 Signaling Pathways

Manilkara zapota (L.) P. Royen, called sapodilla, or locally known as ciku, belongs to the family Sapotaceae. We found that Manilkara zapota leaf water extract has cytotoxic effect against human hepatocellular carcinoma (HepG2) cell line in our earlier study. Therefore, this study aimed to explore the anticancer properties of Manilkara zapota leaf water extract in HepG2 cells. We also aimed to unravel yet undiscovered mechanisms and identified several expressed genes whose functions in cytotoxicity activity of Manilkara zapota leaf water extract in HepG2 cells have not been well-studied. The apoptosis and intracellular reactive oxygen species (ROS) activities were analyzed using Annexin V-propidium iodide staining and dichlorodihydrofluorescein diacetate, respectively, by NovoCyte Flow Cytometer. Bax and Bcl-2 expression were assessed using Enzyme-Linked Immunosorbent Assay. The associated molecular pathways were evaluated by quantitative real-time PCR. Overall analyses revealed that Manilkara zapota leaf water extract can increase percentage of early apoptotic cells, induce the formation of ROS, upregulate c-Jun N-terminal kinase 1 (JNK1) and inducible nitric oxide synthase (iNOS), and reduce Akt1 and vascular endothelial growth factor A (VEGFA) transcriptional activities. Our data suggest that Manilkara zapota leaf water extract can suppress the growth of HepG2 cells via modulation of ERK1/2/Akt1/JNK1 transcriptional expression.

RNA sequencing and de novo assembly of Solanum trilobatum leaf transcriptome to identify putative transcripts for major metabolic pathways

Solanum trilobatum L. is an important medicinal plant in traditional Indian system of medicine belonging to Solanaceae family. However, non-availability of genomic resources hinders its research at the molecular level. We have analyzed the S. trilobatum leaf transcriptome using high throughput RNA sequencing. The de novo assembly of 136,220,612 reads produced 128,934 non-redundant unigenes with N50 value of 1347 bp. Annotation of unigenes was performed against databases such as NCBI nr database, Gene Ontology, KEGG, Uniprot, Pfam, and plnTFDB. A total of 60,097 unigenes were annotated including 48 Transcription Factor families and 14,490 unigenes were assigned to 138 pathways using KEGG database. The pathway analysis revealed the transcripts involved in the biosynthesis of important secondary metabolites contributing for its medicinal value such as Flavonoids. Further, the transcripts were quantified using RSEM to identify the highly regulated genes for secondary metabolism. Reverse-Transcription PCR was performed to validate the de novo assembled unigenes. The expression profile of selected unigenes from flavonoid biosynthesis pathway was analyzed using qRT-PCR. We have also identified 13,262 Simple Sequence Repeats, which could help in molecular breeding. This is the first report of comprehensive transcriptome analysis in S. trilobatum and this will be an invaluable resource to understand the molecular basis related to the medicinal attributes of S. trilobatum in further studies.

Butein suppresses hepatocellular carcinoma growth via modulating Aurora B kinase activity

Aurora B is aberrantly expressed in various tumors and shown to be a promising target for cancer therapy. Butein, a chalcone isolated from Rhus cerniciflua, has demonstrated antitumor activities in different cancers. In this study, we aimed to validate whether Aurora B kinase was the direct target of butein to exhibit its potency in hepatocellular carcinoma (HCC). Comparing with the normal cell line and tissue, Aurora B was overexpressed in all tested HCC cells and the majority of tumor tissue. Knocking down of Aurora B with shRNA substantially inhibited HCC cell proliferation, colony formation and delayed tumor growth in nude mice. Except computer docking, a series of kinase assays revealed butein directly interacted with Aurora B and inhibited its kinase activity. Along with the decrease of Aurora B and histone H3 phosphorylation, HCC cells were induced G2/M cell cycle arrest and subjected to cell apoptosis. Butein-mediated antitumor activities were substantially impaired in Aurora B knockdown cells, suggesting Aurora B was an important target of butein in HCC. Oral administration of butein substantially restrained HCC xenograft growth and the expressions of Ki67 and phosphor-histone H3 were significantly decreased in butein-treated tissue. To the best of our knowledge, our studies revealed that Aurora B was the direct target of butein in HCC.

Cytotoxic Compounds from the Seeds of Sophora alopecuroides

Chemical purification of the ethyl acetate extract from the seeds of Sophora alopecuroides yielded a new natural product, ethyl 2-(4-hydroxybenzyl) malic acid (1), along with 7 known compounds, methyl eucomate (2), eucomic acid (3), piscidic acid (4) and ethyl 2-(4-hydroxybenzyl) tartrate (5), butein-4'-O-β-D-glucopyranoside (6), iso-liquiritigenin (7), and butein (8). The structure of 1 was determined by spectroscopic analyses including extensive 1D (1H NMR, 13C NMR) and 2D NMR spectra (COSY, HSQC and HMBC) as well as MS data. All compounds were evaluated for their cytotoxic activities against hepato-cellular carcinoma (HCC) cell lines, HepG2 andHep3B. Compound 8 significantly inhibited the cancer cell growth in a concentration-dependent manner.

Butein Inhibited In Vitro Hexokinase-2-Mediated Tumor Glycolysis in Hepatocellular Carcinoma by Blocking Epidermal Growth Factor Receptor (EGFR)

BACKGROUND Anaerobic glycolysis is an important physiological process of all cancer cells. Butein has been reported to demonstrate substantial antitumor activities in various cancers. However, the effect of butein on tumor glycolysis remains unclear. In this study, the effect of butein on tumor glycolysis and the underlying mechanism were investigated in hepatocellular carcinoma (HCC). MATERIAL AND METHODS Cell proliferation assay and anchorage-independent growth assay were carried out to evaluate the antitumor activities of butein in vitro. The effect of butein on tumor glycolysis was determined by examining the changes in glucose uptake and lactate production. Hexokinase-2 (HK-2) expression in HCC cells upon butein treatment was analyzed by Western blotting. The activity of butein on EGFR signaling pathway was studied and its potency in EGFR exogenous overexpression cells was investigated. RESULTS After butein treatment, HCC cell proliferation was significantly inhibited (91.4% in Hep3B and 88.2% in Huh-7 at 80 μM, p<0.001). Moreover, the number of colonies formed in the agar was substantially decreased (93.8% in Hep3B and 72.3% in Huh-7 at 80 μM, p<0.001). With the suppression of HK-2 expression, glucose consumption in Hep3B and Huh-7 cells decreased by 48.4% and 56.3%, respectively (p<0.01), and the lactate production also was reduced accordingly (39.5% in Hep3B and 48.6% in Huh-7, p<0.01). Mechanism investigations demonstrated that butein dose-dependently blocked the activation of the EGFR signaling pathway in HCC cells. In EGFR exogenous overexpression cells, the glycolysis suppression exerted by butein was substantially attenuated. CONCLUSIONS Butein has a substantial inhibitory effect on tumor glycolysis in HCC cells, and the glycolysis suppression exerted by butein is closely related to its effect on the EGFR signaling pathway.

Butein activates p53 in hepatocellular carcinoma cells via blocking MDM2-mediated ubiquitination

Introduction

In this study, we aimed to investigate the effect of butein on p53 in hepatocellular carcinoma (HCC) cells and the related molecular mechanisms by which p53 was activated.

Methods

MTS assay and clonogenic survival assay were used to examine the antitumor activity of butein in vitro. Reporter gene assay was adopted to evaluate p53 transcriptional activity. Flow cytometry and western blotting were performed to study apoptosis induction and protein expression respectively. Xenograft model was applied to determine the in vivo efficacy and the expression of p53 in tumor tissue was detected by immunohistochemistry.

Results

HCC cell proliferation and clonogenic survival were significantly inhibited after butein treatment. With the activation of cleaved-PARP and capsase-3, butein induced apoptosis in HCC cells in a dose-dependent manner. The transcriptional activity of p53 was substantially promoted by butein, and the expression of p53-targeted gene was increased accordingly. Mechanism studies demonstrated that the interaction between MDM2 and p53 was blocked by butein and MDM2-mediated p53 ubiquitination was substantially decreased. Short-hairpin RNA experiment results showed that the sensitivity of HCC cells to butein was substantially impaired after p53 was knocked down and butein-induced apoptosis was dramatically decreased. In vivo experiments validated substantial antitumor efficacy of butein against HepG2 xenograft growth, and the expression of p53 in butein-treated tumor tissue was significantly increased.

Conclusion

Butein demonstrated potent antitumor activities in HCC by activating p53, and butein or its analogs had therapeutic potential for HCC management.

Modulation of reactive oxygen species via ERK and STAT3 dependent signalling are involved in the response of mesothelioma cells to exemestane

Pleural mesothelioma is a deadly form of cancer. The prognosis is extremely poor due to the limited treatment modalities. Uptake of asbestos fibres, the leading cause of mesothelioma, lead to the accumulation of reactive-oxygen-species (ROS). Interestingly, increasing ROS production by using ROS-generating drugs may offer a strategy to selectively trigger cell death. Exemestane, an aromatase inhibitor, has previously shown anti-tumor properties in mesothelioma preclinical models suggesting a role of G protein-coupled receptor 30 (GPR30) in the drug response. As exemestane, in addition to blocking estrogen biosynthesis, generates ROS that are able to arrest the growth of breast cancer, we explored the role of ROS, antioxidant defense system, and ROS-induced signalling pathways in mesothelioma cells during exemestane response. Here we report that exemestane treatment reduced cell proliferation with an increase in ROS production and reduction of cyclic adenosine monophosphate (cAMP) levels in MSTO-H211, Ist-Mes1, Ist-Mes2 and MPP89 exemestane-sensitive mesothelioma cell lines, but not in NCI-H2452 exemestane-insensitive mesothelioma cells. Exemestane induced a significant antioxidant response in NCI-H2452 cells, as highlighted by an increase in γ-glutamylcysteine levels, catalase (Cat), superoxide-dismutase and (SOD) and glutathione-peroxidase (GSH-Px) activity and nuclear factor E2-related factor 2 (Nrf2) activation, responsible for drug insensitivity. Conversely, exemestane elevated ROS levels along with increased ERK phosphorylation and a reduction of p-STA3 in exemestane-sensitive mesothelioma cells. ROS generation was the crucial event of exemestane action because ROS inhibitor N-acetyl-L-cysteine (NAC) abrogated p-ERK and p-STAT3 modulation and cellular death. Exemestane also modulates ERK and STAT3 signalling via GPR30. Results indicate an essential role of ROS in the antiproliferative action of exemestane in mesothelioma cells. It is likely that the additional oxidative insults induced by exemestane results in the lethal effects of mesothelioma cells by increasing ROS production. As such, manipulating ROS levels with exemestane seems to be a feasible strategy to selectively kill mesothelioma cells with less toxicity to normal cells by regulating ERK and STAT3 activity.

Molecular chemotherapeutic potential of butein: A concise review

Butein is a biologically active flavonoid isolated from the bark of Rhus verniciflua Stokes, which is known to have therapeutic potential against various cancers. Notably, butein inhibits cancer cell growth by inducing G₂/M phase arrest and apoptosis. Butein-induced G₂/M phase arrest is associated with increased phosphorylation of ataxia telangiectasia mutated (ATM) and Chk1/2, and consequently, with reduced cdc25C levels. In addition, butein-induced apoptosis is mediated through the activation of caspase-3, which is associated with changes in the expression of Bcl-2 and Bax proteins. Intriguingly, butein sensitizes cells to tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis via ERK-mediated Sp1 activation, which promotes the transcription of specific death receptor 5. Butein also inhibits the migration and invasion of human cancer cells by suppressing nuclear factor-κB- and extracellular signal-regulated kinases 1/2-mediated expression of matrix metalloproteinase-9 and vascular endothelial growth factor. Additionally, butein downregulates the expression of human telomerase reverse transcriptase and causes a concomitant decrease in telomerase activity. These findings provide the basis for the pharmaceutical development of butein. The aim of this review is to provide an update on the mechanisms underlying the anticancer activity of butein, with a special focus on its effects on different cellular signaling cascades.

Butein in health and disease: A comprehensive review

BACKGROUND

The risk of suffering from many chronic diseases seems to have made no improvement despite the advancement in medications available in the modern world. Moreover, the use of synthetic chemicals as medications has proved to worsen the scenario due to the various adverse side effects associated with them.

PURPOSE

Extensive research on natural medicines provides ample evidence on the safety and efficacy of phytochemicals and nutraceuticals against diverse chronic ailments. Therefore, it is advisable to use natural products in the management of such diseases. This article aims to present a comprehensive and critical review of known pharmacological and biological effects of butein, an important chalcone polyphenol first isolated from Rhus verniciflua Stokes, implicated in the prevention and treatment of various chronic disease conditions.

METHODS

An extensive literature search was conducted using PubMed, ScienceDirect, Scopus and Web of Science^TM core collections using key words followed by evaluation of the bibliographies of relevant articles.

RESULTS

Butein has been preclinically proven to be effective against several chronic diseases because it possesses a wide range of biological properties, including antioxidant, anti-inflammatory, anticancer, antidiabetic, hypotensive and neuroprotective effects. Furthermore, it has been shown to affect multiple molecular targets, including the master transcription factor nuclear factor-κB and its downstream molecules. Moreover, since it acts on multiple pathways, the chances of non-responsiveness and resistance development is reduced, supporting the use of butein as a preferred treatment option.

CONCLUSION

Based on numerous preclinical studies, butein shows significant therapeutic potential against various diseases. Nevertheless, well-designed clinical studies are urgently needed to validate the preclinical findings.

Butein induction of HO-1 by p38 MAPK/Nrf2 pathway in adipocytes attenuates high-fat diet induced adipose hypertrophy in mice

Adipose tissue inflammation and oxidative stress are key components in the development of obesity and insulin resistance. Heme oxygenase (HO)-1 in adipocytes protects against obesity and adipose dysfunction. In this study, we report the identification of butein, a flavonoid chalcone, as a novel inducer of HO-1 expression in adipocytes in vitro and in vivo. Butein upregulated HO-1 mRNA and protein expression in 3T3-L1 adipocytes, accompanied by Kelch-Like ECH-Associated Protein (Keap) 1 degradation and increase in the nuclear level of nuclear factor erythroid 2-related factor 2 (Nrf2). Butein modulation of Keap1 and Nrf2 as well as HO-1 upregulation was reversed by pretreatment with p38 MAPK inhibitor SB203580, indicating the involvement of p38 MAPK in butein activation of Nrf2 in adipocytes. In addition, HO-1 activation by butein led to the inhibitions of reactive oxygen species and adipocyte differentiation, as evidenced by the fact that butein repression of reactive oxygen species and adipogenesis was reversed by pretreatment with HO-1 inhibitor SnPP. Induction of HO-1 expression by butein was also demonstrated in the adipose tissue of C57BL/6 mice fed a high-fat diet administered along with butein for three weeks, and correlated with the inhibitions of adiposity and adipose tissue inflammation, which were reversed by co-administration of SnPP. Altogether, our results demonstrate that butein activates the p38 MAPK/Nrf2/HO-1 pathway to act as a potent inhibitor of adipose hypertrophy and inflammation in a diet-induced obesity model and thus has potential for suppressing obesity-linked metabolic syndrome.

Naringenin inhibits migration of lung cancer cells via the inhibition of matrix metalloproteinases-2 and -9

Lung cancer is among the most common causes of cancer-related mortality. It has a high mortality rate and resistance to chemotherapy due to its high metastatic potential. Naringenin, a bioactive compound identified in several fruits, displays anti-inflammatory and antitumor effects. Furthermore, naringenin mitigates the migration of several human cancer cell types. However, the effects of naringenin on lung cancer remain unclear. The current study investigated the mechanisms of naringenin on the migration of lung cancer A549 cells. The results indicate that significant alteration in A549 cell proliferation was observed in response to naringenin (0-300 µM) treatment for 24 and 48 h. Furthermore, a dose-dependent migration inhibition of A549 in the presence of naringenin was observed by healing and transwell migration assays. In addition, a zymography assay revealed that naringenin exhibited a concentration-dependent inhibition of matrix metalloproteinase (MMP)-2 and -9 activities. Furthermore, naringenin also inhibited the activities of AKT in a dose-dependent manner. These observations indicated that naringenin inhibited the migration of lung cancer A549 cells through several mechanisms, including the inhibition of AKT activities and reduction of MMP-2 and -9 activities.

Sequencing, De novo Assembly, Functional Annotation and Analysis of Phyllanthus amarus Leaf Transcriptome Using the Illumina Platform

Phyllanthus amarus Schum. and Thonn., a widely distributed annual medicinal herb has a long history of use in the traditional system of medicine for over 2000 years. However, the lack of genomic data for P. amarus, a non-model organism hinders research at the molecular level. In the present study, high-throughput sequencing technology has been employed to enhance better understanding of this herb and provide comprehensive genomic information for future work. Here P. amarus leaf transcriptome was sequenced using the Illumina Miseq platform. We assembled 85,927 non-redundant (nr) "unitranscript" sequences with an average length of 1548 bp, from 18,060,997 raw reads. Sequence similarity analyses and annotation of these unitranscripts were performed against databases like green plants nr protein database, Gene Ontology (GO), Clusters of Orthologous Groups (COG), PlnTFDB, KEGG databases. As a result, 69,394 GO terms, 583 enzyme codes (EC), 134 KEGG maps, and 59 Transcription Factor (TF) families were generated. Functional and comparative analyses of assembled unitranscripts were also performed with the most closely related species like Populus trichocarpa and Ricinus communis using TRAPID. KEGG analysis showed that a number of assembled unitranscripts were involved in secondary metabolites, mainly phenylpropanoid, flavonoid, terpenoids, alkaloids, and lignan biosynthetic pathways that have significant medicinal attributes. Further, Fragments Per Kilobase of transcript per Million mapped reads (FPKM) values of the identified secondary metabolite pathway genes were determined and Reverse Transcription PCR (RT-PCR) of a few of these genes were performed to validate the de novo assembled leaf transcriptome dataset. In addition 65,273 simple sequence repeats (SSRs) were also identified. To the best of our knowledge, this is the first transcriptomic dataset of P. amarus till date. Our study provides the largest genetic resource that will lead to drug development and pave the way in deciphering various secondary metabolite biosynthetic pathways in P. amarus, especially those conferring the medicinal attributes of this potent herb.

p53 causes butein‑mediated apoptosis of chronic myeloid leukemia cells

Progression of chronic myeloid leukemia, marked by the oncogenic Bcr‑Abl mutation, is tightly associated with an alteration of the p53 pathway. It is known that butein extracted from various plants represses cancer growth. Although the anticancer effects of butein are widely accepted, the mechanisms by which butein induces apoptosis of chronic myeloid leukemia cells remains to be elucidated. The present study demonstrated that butein-induced apoptosis was mediated by p53. KBM5 chronic myeloid leukemia (CML) cells expressing wild-type p53 were more sensitive to butein compared with p53-null K562 CML cells in terms of apoptotic cell death. In addition, butein arrested KBM5 cells at S-phase and altered the expression levels of certain cyclins and the p53-downstream targets, MDM2 and p21. In addition, while butein reduced the protein expression of MDM2 in the KBM5 and K562 cells, it resulted in proteasome-independent MDM2 degradation in p53-expressing KBM5 cells, however, not in p53-null K562 cells. Therefore, the present study suggested that p53 causes the butein-mediated apoptosis of leukemic cells.

Potential of butein, a tetrahydroxychalcone to obliterate cancer

BACKGROUND

Despite the major advances made in the field of cancer biology, it still remains one of the most fatal diseases in the world. It is now well established that natural products are safe and efficacious and have high potential in the prevention and treatment of different diseases including cancer. Butein is one such compound which is now found to have anti-cancer properties against various malignancies.

PURPOSE

To thoroughly review the literature available on the anti-cancer properties of butein against different cancers and its molecular targets.

METHODS

A thorough literature search has been done in PubMed for butein, its biological activities especially cancer and its molecular targets.

RESULTS

Our search retrieved several reports on the various biological activities of butein in which around 43 articles reported that butein shows potential anti-proliferative effect against a wide range of neoplasms and the molecular target varies with cancer types. Most often it targets NF-κB and its downstream pathways. In addition, butein induces the expression of genes which mediate the cell death and apoptosis in cancer cells. It also inhibits tumor angiogenesis, invasion and metastasis in prostate, liver and bladder cancers through the inhibition of MMPs, VEGF etc. Moreover, it inhibits the overexpression of several proteins and enzymes such as STAT3, ERK, CXCR4, COX-2, Akt, EGFR, Ras etc. involved in tumorigenesis.

CONCLUSION

Collectively, all these findings suggest the enormous potential and efficacy of butein as a multitargeted chemotherapeutic, chemopreventive and chemosensitizing agent against a wide range of cancers with minimal or no adverse side effects.

Butein sensitizes HeLa cells to cisplatin through the AKT and ERK/p38 MAPK pathways by targeting FoxO3a

Drug resistance remains a major challenge in cancer therapy. Butein, a polyphenolic compound, has been shown to exhibit anticancer activity through the inhibition of the activation of the protein kinase B (PKB/AKT) and mitogen-activated protein kinase (MAPK) pathways, which are two pathways known to be involved in resistance to cisplatin. Hence, we hypotheiszed that butein may be a chemosensitizer to cisplatin. In the present study, we demonstrated that butein synergistically enhanced the growth inhibitory and apoptosis-inducing effects of cisplatin on HeLa cells. Moreover, the combination of butein and cisplatin led to G1 phase arrest. We then aimed to explore the underlying mechanisms. We found that butein inhibited the activation of AKT, extracellular signal-regulated kinase (ERKs) and p38 kinases in the presence of cisplatin. The use of the AKT inhibitor, LY294002, in combination with cisplatin, induced an increase in apoptosis compared to treatment with cisplatin alone, although this effect was not as prominent as that exerted by butein in combination with cisplatin. Of note, the inhibition of ERK or p38 MAPK by U0126 or SB203580, respectively, decreased the apoptosis induced by cisplatin; however, enhanced apoptotic effects were observed with the use of ERK/p38 MAPK inhibitor in combination with butein. These data suggest that the AKT and ERK/p38 MAPK pathways are involved in the synergistic effects of butein and cisplatin. Furthermore, co-treatment with butein and cisplatin promoted the nuclear translocation and expression of forkhead box O3a (FoxO3 or FoxO3a). FoxO3a may be the key molecule on which these pathways converge and is thus implicated in the synergistic effects of butein and cisplatin. This was further confirmed by the RNAi-mediated suppression of FoxO3a. FoxO3a target genes involved in cell cycle progression and apoptosis were also investigated, and combined treatment with butein and cisplatin resulted in the downregulation of cyclin D1 and Bcl-2 and the upregulation of p27 and Bax. In addition, the combination of both agents markedly inhibited tumor growth and increased the expression of FoxO3a in mouse tumor xenograft models of cervical cancer. Taken together, to the best of our knowledge, our results reveal for the first time that butein sensitizes cervical cancer cells to cisplatin in vitro and in vivo, and these effects of butien may be related to the inhibition of the activation of the AKT and ERK/p38 MAPK pathways by targeting FoxO3a.

ROS-p53-cyclophilin-D signaling mediates salinomycin-induced glioma cell necrosis

BACKGROUND

The primary glioblastoma multiforme (GBM) is the most malignant form of astrocytic tumor with an average survival of approximately 12-14 months. The search for novel and more efficient chemo-agents against this disease is urgent. Salinomycin induces broad anti-cancer effects; however, its role in GBM and the underlying mechanism are not clear.

RESULTS

Here we found that salinomycin induced both apoptosis and necrosis in cultured glioma cells, and necrosis played a major role in contributing salinomycin's cytotoxicity. Salinomycin induced p53 translocation to mitochondria, where it formed a complex with cyclophilin-D (CyPD). This complexation was required for mitochondrial permeability transition pore (mPTP) opening and subsequent programmed necrosis. Blockade of Cyp-D by siRNA-mediated depletion or pharmacological inhibitors (cyclosporin A and sanglifehrin A) significantly suppressed salinomycin-induced glioma cell necrosis. Meanwhile, p53 stable knockdown alleviated salinomycin-induced necrosis in glioma cells. Reactive oxygen species (ROS) production was required for salinomycin-induced p53 mitochondrial translocation, mPTP opening and necrosis, and anti-oxidants n-acetylcysteine (NAC) and pyrrolidine dithiocarbamate (PDTC) inhibited p53 translocation, mPTP opening and glioma cell death.

CONCLUSIONS

Thus, salinomycin mainly induces programmed necrosis in cultured glioma cells.

Bromelain and N-acetylcysteine inhibit proliferation and survival of gastrointestinal cancer cells in vitro: significance of combination therapy

BACKGROUND

Bromelain and N-acetylcysteine are two natural, sulfhydryl-containing compounds with good safety profiles which have been investigated for their benefits and application in health and disease for more than fifty years. As such, the potential values of these agents in cancer therapy have been variably reported in the literature. In the present study, the efficacy of bromelain and N-acetylcysteine in single agent and combination treatment of human gastrointestinal carcinoma cells was evaluated in vitro and the underlying mechanisms of effect were explored.

METHODS

The growth-inhibitory effects of bromelain and N-acetylcysteine, on their own and in combination, on a panel of human gastrointestinal carcinoma cell lines, including MKN45, KATO-III, HT29-5F12, HT29-5M21 and LS174T, were assessed by sulforhodamine B assay. Moreover, the influence of the treatment on the expression of a range of proteins involved in the regulation of cell cycle and survival was investigated by Western blot. The presence of apoptosis was also examined by TUNEL assay.

RESULTS

Bromelain and N-acetylcysteine significantly inhibited cell proliferation, more potently in combination therapy. Drug-drug interaction in combination therapy was found to be predominantly synergistic or additive. Mechanistically, apoptotic bodies were detected in treated cells by TUNEL assay. Furthermore, Western blot analysis revealed diminution of cyclins A, B and D, the emergence of immunoreactive subunits of caspase-3, caspase-7, caspase-8 and cleaved PARP, withering or cleavage of procaspase-9, overexpression of cytochrome c, reduced expression of anti-apoptotic Bcl-2 and pro-survival phospho-Akt, the emergence of the autophagosomal marker LC3-II and deregulation of other autophagy-related proteins, including Atg3, Atg5, Atg7, Atg12 and Beclin 1. These results were more prominent in combination therapy.

CONCLUSION

We report for the first time to our knowledge the growth-inhibitory and cytotoxic effects of bromelain and N-acetylcysteine, in particular in combination, on a panel of gastrointestinal cancer cell lines with different phenotypes and characteristics. These effects apparently resulted from cell cycle arrest, apoptosis and autophagy. Towards the development of novel strategies for the enhancement of microscopic cytoreduction, our results lay the basis for further evaluation of this formulation in locoregional approaches to peritoneal surface malignancies and carcinomatosis.

Bromelain and N-acetylcysteine inhibit proliferation and survival of gastrointestinal cancer cells in vitro: significance of combination therapy

Background

Bromelain and N-acetylcysteine are two natural, sulfhydryl-containing compounds with good safety profiles which have been investigated for their benefits and application in health and disease for more than fifty years. As such, the potential values of these agents in cancer therapy have been variably reported in the literature. In the present study, the efficacy of bromelain and N-acetylcysteine in single agent and combination treatment of human gastrointestinal carcinoma cells was evaluated in vitro and the underlying mechanisms of effect were explored.

Methods

The growth-inhibitory effects of bromelain and N-acetylcysteine, on their own and in combination, on a panel of human gastrointestinal carcinoma cell lines, including MKN45, KATO-III, HT29-5F12, HT29-5M21 and LS174T, were assessed by sulforhodamine B assay. Moreover, the influence of the treatment on the expression of a range of proteins involved in the regulation of cell cycle and survival was investigated by Western blot. The presence of apoptosis was also examined by TUNEL assay.

Results

Bromelain and N-acetylcysteine significantly inhibited cell proliferation, more potently in combination therapy. Drug-drug interaction in combination therapy was found to be predominantly synergistic or additive. Mechanistically, apoptotic bodies were detected in treated cells by TUNEL assay. Furthermore, Western blot analysis revealed diminution of cyclins A, B and D, the emergence of immunoreactive subunits of caspase-3, caspase-7, caspase-8 and cleaved PARP, withering or cleavage of procaspase-9, overexpression of cytochrome c, reduced expression of anti-apoptotic Bcl-2 and pro-survival phospho-Akt, the emergence of the autophagosomal marker LC3-II and deregulation of other autophagy-related proteins, including Atg3, Atg5, Atg7, Atg12 and Beclin 1. These results were more prominent in combination therapy.

Conclusion

We report for the first time to our knowledge the growth-inhibitory and cytotoxic effects of bromelain and N-acetylcysteine, in particular in combination, on a panel of gastrointestinal cancer cell lines with different phenotypes and characteristics. These effects apparently resulted from cell cycle arrest, apoptosis and autophagy. Towards the development of novel strategies for the enhancement of microscopic cytoreduction, our results lay the basis for further evaluation of this formulation in locoregional approaches to peritoneal surface malignancies and carcinomatosis.