A decisive role of mitochondria in defining rate and intensity of apoptosis induction by different alkaloids

Tap the sap - investigation of latex-bearing plants in the search of potential anticancer biopharmaceuticals

Latex-bearing plants have been in the research spotlight for the past couple of decades. Since ancient times their extracts have been used in folk medicine to treat various illnesses. Currently they serve as promising candidates for cancer treatment. Up to date there have been several in vitro and in vivo studies related to the topic of cytotoxicity and anticancer activity of extracts from latex-bearing plants towards various cell types. The number of clinical studies still remains scarce, however, over the years the number is systematically increasing. To the best of our knowledge, the scientific community is still lacking in a recent review summarizing the research on the topic of cytotoxicity and anticancer activity of latex-bearing plant extracts. Therefore, the aim of this paper is to review the current knowledge on in vitro and in vivo studies, which focus on the cytotoxicity and anticancer activities of latex-bearing plants. The vast majority of the studies are in vitro, however, the interest in this topic has resulted in the substantial growth of the number of in vivo studies, leading to a promising number of plant species whose latex can potentially be tested in clinical trials. The paper is divided into sections, each of them focuses on specific latex-bearing plant family representatives and their potential anticancer activity, which in some instances is comparable to that induced by commonly used therapeutics currently available on the market. The cytotoxic effect of the plant's crude latex, its fractions or isolated compounds, is analyzed, along with a study of cell apoptosis, chromatin condensation, DNA damage, changes in gene regulation and morphology changes, which can be observed in cell post plant extract addition. The in vivo studies go beyond the molecular level by showing significant reduction of the tumor growth and volume in animal models. Additionally, we present data regarding plant-mediated biosynthesis of nanoparticles, which is regarded as a new branch in plant latex research. It is solely based on the green-synthesis approach, which presents an interesting alternative to chemical-based nanoparticle synthesis. We have analyzed the cytotoxic effect of these particles on cells. Data regarding the cytotoxicity of such particles raises their potential to be involved in the design of novel cancer therapies, which further underlines the significance of latex-bearing plants in biotechnology. Throughout the course of this review, we concluded that plant latex is a rich source of many compounds, which can be further investigated and applied in the design of anticancer pharmaceuticals. The molecules, to which this cytotoxic effect can be attributed, include alkaloids, flavonoids, tannins, terpenoids, proteases, nucleases and many novel compounds, which still remain to be characterized. They have been studied extensively in both in vitro and in vivo studies, which provide an excellent starting point for their rapid transfer to clinical studies in the near future. The comprehensive study of molecules from latex-bearing plants can result in finding a promising alternative to several pharmaceuticals on the market and help unravel the molecular mode of action of latex-based preparations.

Rediscovery of Traditional Plant Medicine: An Underestimated Anticancer Drug of Chelerythrine

In many studies, the extensive and significant anticancer activity of chelerythrine (CHE) was identified, which is the primary natural active compound in four traditional botanical drugs and can be applied as a promising treatment in various solid tumors. So this review aimed to summarize the anticancer capacities and the antitumor mechanism of CHE. The literature searches revolving around CHE have been carried out on PubMed, Web of Science, ScienceDirect, and MEDLINE databases. Increasing evidence indicates that CHE, as a benzophenanthridine alkaloid, exhibits its excellent anticancer activity as CHE can intervene in tumor progression and inhibit tumor growth in multiple ways, such as induction of cancer cell apoptosis, cell cycle arrest, prevention of tumor invasion and metastasis, autophagy-mediated cell death, bind selectively to telomeric G-quadruplex and strongly inhibit the telomerase activity through G-quadruplex stabilization, reactive oxygen species (ROS), mitogen-activated protein kinase (MAPK), and PKC. The role of CHE against diverse types of cancers has been investigated in many studies and has been identified as the main antitumor drug candidate in drug discovery programs. The current complex data suggest the potential value in clinical application and the future direction of CHE as a therapeutic drug in cancer. Furthermore, the limitations and the present problems are also highlighted in this review. Despite the unclearly delineated molecular targets of CHE, extensive research in this area provided continuously fresh data exploitable in the clinic while addressing the present requirement for further studies such as toxicological studies, combination medication, and the development of novel chemical methods or biomaterials to extend the effects of CHE or the development of its derivatives and analogs, contributing to the effective transformation of this underestimated anticancer drug into clinical practice. We believe that this review can provide support for the clinical application of a new anticancer drug in the future.

Sanguinarine mediated apoptosis in Non-Small Cell Lung Cancer via generation of reactive oxygen species and suppression of JAK/STAT pathway

Effective treatment of lung cancer remains a significant clinical challenge due to its multidrug resistance and side effects of the current treatment options. The high mortality associated with this malignancy indicates the need for new therapeutic interventions with fewer side effects. Natural compounds offer various benefits such as easy access, minimal side effects, and multi-molecular targets and thus, can prove useful in treating lung cancer. Sanguinarine (SNG), a natural compound, possesses favorable therapeutic potential against a variety of cancers. Here, we examined the underlying molecular mechanisms of SNG in Non-Small Cell Lung Cancer (NSCLC) cells. SNG suppressed cell growth and induced apoptosis via downregulation of the constitutively active JAK/STAT pathway in all the NSCLC cell lines. siRNA silencing of STAT3 in NSCLC cells further confirmed the involvement of the JAK/STAT signaling cascade. SNG treatment increased Bax/Bcl-2 ratio, which contributed to a leaky mitochondrial membrane leading to cytochrome c release accompanied by caspase activation. In addition, we established the antitumor effects of SNG through reactive oxygen species (ROS) production, as inhibiting ROS production prevented the apoptosis-inducing potential of SNG. In vivo xenograft tumor model further validated our in vitro findings. Overall, our study investigated the molecular mechanisms by which SNG induces apoptosis in NSCLC, providing avenues for developing novel natural compound-based cancer therapies.

Comparative Study of Bioactivity and Safety Evaluation of Ethanolic Extracts of Zanthoxylum schinifolium Fruit and Pericarp

The fruit and pericarp of Zanthoxylum schinifolium (ZS) have been used in traditional medicine; however, few studies have characterized ZS fruit and pericarp. Therefore, in the present study, we evaluated the safety of ZS fruit (ZSF) and pericarp (ZSP) extracts and compared their bioactivity. To evaluate the safety of ZSF and ZSP, mutagenicity, cytotoxicity, and oxidative stress assays were performed and nontoxic concentration ranges were obtained. ZSP was found to be superior to ZSF in terms of its antimutagenic, antioxidant, and anti-inflammatory activities. In the S9 mix, the mutation inhibition rate of ZSP was close to 100% at concentrations exceeding 625 µg·plate⁻¹ for both the TA98 and TA100 strains. ZSP exhibited efficient DPPH (IC₅₀ = 75.6 ± 6.1 µg·mL⁻¹) and ABTS (IC₅₀ = 57.4 ± 6 µg·mL⁻¹) scavenging activities. ZSP inhibited the release of cytokines, involved in IL-1β (IC₅₀ = 134.4 ± 7.8), IL-6 (IC₅₀ = 262.8 ± 11.2), and TNF-α (IC₅₀ = 223.8 ± 5.8). These results indicate that ZSP contains a higher amount of biochemicals than ZSF, or that ZSP contains unique biochemicals. In conclusion, for certain physiological activities, the use of ZSP alone may be more beneficial than the combined use of ZSF and ZSP.

Reactive oxygen species (ROS) in cancer pathogenesis and therapy: An update on the role of ROS in anticancer action of benzophenanthridine alkaloids

Reactive oxygen species play crucial role in biological homeostasis and pathogenesis of human diseases including cancer. In this line, now it has become evident that ROS level/concentration is a major factor in the growth, progression and stemness of cancer cells. Moreover, cancer cells maintain a delicate balance between ROS and antioxidants to promote pathogenesis and clinical challenges via targeting a battery of signaling pathways converging to cancer hallmarks. Recent findings also entail the therapeutic importance of ROS for the better clinical outcomes in cancer patients as they induce apoptosis and autophagy. Moreover, poor clinical outcomes associated with cancer therapies are the major challenge and use of natural products have been vital in attenuation of these challenges due to their multitargeting potential with less adverse effects. In fact, most available drugs are derived from natural resources, either directly or indirectly and available evidence show the clinical importance of natural products in the management of various diseases, including cancer. ROS play a critical role in the anticancer actions of natural products, particularly phytochemicals. Benzophenanthridine alkaloids of the benzyl isoquinoline family of alkaloids, such as sanguinarine, possess several pharmacological properties and are thus being studied for the treatment of different human diseases, including cancer. In this article, we review recent findings, on how benzophenanthridine alkaloid-induced ROS play a critical role in the attenuation of pathological changes and stemness features associated with human cancers. In addition, we highlight the role of ROS in benzophenanthridine alkaloid-mediated activation of the signaling pathway associated with cancer cell apoptosis and autophagy.

Mitochondria-targeted ratiometric fluorescent imaging of cysteine

As an indispensable biothiol, cysteine (Cys) plays a critical part in cellular redox homeostasis, and pathological and physiological processes. One of the main sources of reactive oxygen species (ROS) in human cells is the substrate end of the respiratory chain in the mitochondrial inner membrane. Therefore, it is valuable to develop probes targeting mitochondria to detect Cys. In this work, we designed a novel fluorescent probe, 2-(2-(6-(acryloyloxy) naphthalen-2-yl) vinyl)-3-ethylbenzothiazol-3-ium (ANET). The naphthyl benzothiazole is the fluorophore group and the acrylate moiety is the Cys response site to avoid the interference of homocysteine (Hcy) and glutathione (GSH). ANET combines multiple strengths for detecting Cys: targeting mitochondria, ratiometric fluorescence, high selectivity, and a large Stokes shift. After ANET reacted with Cys, the fluorescence signals changed from green (λem = 525 nm) to orange red (λem = 595 nm), and the detection limit was calculated to be 74 nM through a linear relationship between ratiometric fluorescence F595/F525 and Cys concentration. The imaging of Cys was confirmed in HepG2 cells.

Development of Natural Bioactive Alkaloids: Anticancer perspective

Cancer is a frightful disease that still poses a 'nightmare' worldwide, causing millions of casualties annually due to one of the human race's most significant healthcare challenges that requires a pragmatic treatment strategy. However, plants and plant-derived products revolutionize the field as they are quick, cleaner, eco-friendly, low-cost, effective, and less toxic than conventional treatment methods. Plants are repositories for new chemical entities and have a promising cancer research path, supplying 60% of the anticancer agents currently used. Alkaloids are important chemical compounds that serve as a rich reservoir for drug discovery and development. However, some alkaloids derived from natural herbs display anti-proliferation and antimetastatic activity on different forms of cancer, both in vitro and in vivo. Alkaloids have also been widely formulated as anticancer medications, such as camptothecin and vinblastine. Still, more research and clinical trials are required before final recommendations can be made on specific alkaloids. This review focuses on the naturally-derived bioactive alkaloids with prospective anticancer properties based on the information in the literature.

Isolation and purification of alkaloids from the fruits of Macleaya cordata by ionic-liquid-modified high-speed counter-current chromatography

Macleaya cordata (Willd) R. Br. is a medicinal plant. The most important bioactive compounds of M. cordata are alkaloids that have many biological activities including antifungal, anti-inflammatory, and antitumor. In this study, an ionic-liquid-modified high-speed counter-current chromatography method was established to obtain alkaloids from the fruits of M. cordata. The conditions of ionic-liquid-modified high-speed counter-current chromatography, including solvent systems, the content of ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate [C₄ mim][BF₄ ]), and the posttreatment of the ionic liquid, were investigated. Five alkaloids protopine, allocryptopine, sanguinarine, 8-O-demethylchelerythrine, and chelerythrine were separated from the extract of the fruits using a high speed counter-current chromatography with two-phase solvent system composed of dichloromethane/methanol/0.3 mol/L hydrochloric acid aqueous solution/[C₄ mim][BF₄ ] (4:2:2:0.015, v/v). Their purities were 96.33, 95.56, 97.94, 96.22, and 97.90%, respectively. The results indicated that a small amount of ionic liquids as modifier of the two-phase solvent system could shorten the separation time and improve the separation efficiency of the alkaloids from the fruits. The ionic-liquid-modified high-speed counter-current chromatography would provide a feasible way for highly effective separation of alkaloids from natural products.

Design, synthesis and apoptosis-related antiproliferative activities of chelidonine derivatives

To get chelidonine derivatives with enhanced antiproliferative activity and selectivity, a series of nitric oxide donating derivatives (10a-f and 11a-j) were designed, synthesized and biologically evaluated. Compared with chelidonine, these compounds exhibited lower IC₅₀ values against human hepatoma cells HepG2, breast cancer cells MCF-7, colon cancer cells HCT-116, as well as leukemia cells K562. Compound 11j displayed the strongest antiproliferative activity with IC₅₀ values of 3.91, 6.90, 4.36 and 1.12 μM against the above four cells, respectively. Nevertheless, it showed an IC₅₀ value >40 μM against human peripheral blood mononuclear cells (PBMCs), which demonstrated high selectivity between normal and cancer blood cells. In further mechanism studies, 11j showed the capability to induce K562 cells apoptosis, S phase cell cycle arrest and mitochondrial membrane potential disorder. Besides, 11j was found to be effective in promoting the expression of proapoptotic protein Bad and suppressing the expression of anti-apoptotic proteins Bcl-xL, catalase, survivin, claspin and clusterin.

Sanguinarine Induces Apoptosis Pathway in Multiple Myeloma Cell Lines via Inhibition of the JaK2/STAT3 Signaling

Sanguinarine (SNG), a benzophenanthridine alkaloid, has displayed various anticancer abilities in several vivo and in vitro studies. However, the anticancer potential of SNG is yet to be established in multiple myeloma (MM), a mostly incurable malignancy of plasma cells. In this study, we aimed to investigate the potential anti-proliferative and pro-apoptotic activities of SNG in a panel of MM cell lines (U266, IM9, MM1S, and RPMI-8226). SNG treatment of MM cells resulted in a dose-dependent decrease in cell viability through mitochondrial membrane potential loss and activation of caspase 3, 9, and cleavage of PARP. Pre-treatment of MM cells with a universal caspase inhibitor, Z-VAD-FMK, prevented SNG mediated loss of cell viability, apoptosis, and caspase activation, confirming that SNG-mediated apoptosis is caspase-dependent. The SNG-mediated apoptosis appears to be resulted from suppression of the constitutively active STAT3 with a concomitant increase in expression of protein tyrosine phosphatase (SHP-1). SNG treatment of MM cells leads to down-regulation of the anti-apoptotic proteins including cyclin D, Bcl-2, Bclxl, and XIAP. In addition, it also upregulates pro-apoptotic protein, Bax. SNG mediated cellular DNA damage in MM cell lines by induction of oxidative stress through the generation of reactive oxygen species and depletion of glutathione. Finally, the subtoxic concentration of SNG enhanced the cytotoxic effects of anticancer drugs bortezomib (BTZ) by suppressing the viability of MM cells via induction of caspase-mediated apoptosis. Altogether our findings demonstrate that SNG induces mitochondrial and caspase-dependent apoptosis, generates oxidative stress, and suppresses MM cell lines proliferation. In addition, co-treatment of MM cell lines with sub-toxic doses of SNG and BTZ potentiated the cytotoxic activity. These results would suggest that SNG could be developed into therapeutic agent either alone or in combination with other anticancer drugs in MM.

Synthesis and Anticancer Activity Evaluation of Novel Phenanthridine Derivatives

Based on the structure of sanguinarine, fourteen phenanthridine derivatives were designed and synthesized in the current study. The cytotoxic activities of synthesized compounds were evaluated against five human cancer cell lines (MCF-7, PC3, Hela, A549, and HepG2 cell lines) via MTT assay. Among all the compounds tested, molecule 8a exhibited significant cytotoxic activity against MCF-7 cells with a IC₅₀ value of 0.28 μM. A following up enzymatic assay indicated that compound 8a could inhibit the activity of DNA topoisomerase I/II. Further mechanistic studies performed in the MCF-7 cell line revealed that compound 8a could arrest cell cycle in S phase and induce cell apoptosis via downregulation of Bcl-2 and upregulation of Bax. Collectively, a potent DNA topoisomerase inhibitor (8a) was discovered, which exhibited potential as a candidate chemotherapeutic agent for the management of tumors in the present study.

Effects of 2-aryl-1-cyano-1,2,3,4-tetrohydroisoquinolines on apoptosis induction mechanism in NB4 and MKN-45 cells

Our previous study found that 2-aryl-1-cyano-1,2,3,4-tetrahydroisoquinolines (CATHIQs) have excellent anti-cancer activity and obvious apoptosis induction phenomenon. As our continuing research, this study further explored their underlying molecular mechanism of apoptosis induction in cancer cells. Flow cytometry analysis showed that the NB4 cells treated by 1-cyano-2-(2-fluorophenyl)-1,2,3,4-tetrahydroisoquinoline or the MKN-45 cells treated by 1-cyano-2-(4-trifluoromethylphenyl)-1,2,3,4-tetrahydroisoquinoline for 48 h were at early stage of apoptosis, and the cell cycle arrest was only slightly affected. Apoptosis rates of the cells significantly increase with the treatment concentration of the compounds. The compounds could significantly decrease the activities of SOD, raise the MDA level and promote the LDH leakage, suggesting that the excessive formation of ROS should be involved in the cell apoptosis. Western blot analysis showed that the compounds improved both Bax/Bcl-2 ratio and cleavages of procaspase-3, promoted efflux of cytochrome c to cytosol and phosphorylation of p38 and JNK, and attenuated phosphorylations of Akt and ERK. Together, inhibitions of PI3K/Akt and ERK and activation of p38 mediated the compounds-induced apoptosis through modulating the mitochondrial pathway and/or ROS production.

Necrosis in human neuronal cells exposed to paraquat

Paraquat (PQ) is an herbicide that was once used worldwide, but is now prohibited in many nations due to its high toxicity to humans. However, there are still rare cases of the fetal intoxication of PQ, which was purchased prior to the prohibition in Japan. In this study, several cell death pathways, the mitochondrial stress response, and autophagy were examined in SH-SY5Y cells exposed to PQ. The results reveal the decrease of a mitochondrial stress sensitive-BNIP3 (Bcl-2/adenovirus E1B 19-kDa-interacting protein 3) protein, the suppression of autophagic flux, and the lack of apoptosis as well as other regulated forms of necrosis, such as necroptosis and ferroptosis. Taken together, our preliminary survey of cellular responses against PQ shows that, although responses of mitochondria and autophagy are observed, subsequent cell death is necrosis. Mechanism of PQ-induced SH-SY5Y cell death should be complicated and cannot be explained thoroughly by already-known mechanisms.

Medicinal plants of the genus Macleaya (Macleaya cordata, Macleaya microcarpa): A review of their phytochemistry, pharmacology, and toxicology

In the genus Macleaya, Macleaya cordata and Macleaya microcarpa have been recognized as traditional herbs that are primarily distributed in China, North America, and Europe and have a long history of medicinal usage. These herbs have been long valued and studied for detumescence, detoxification, and insecticidal effect. This review aims to provide comprehensive information on botanical, phytochemical, pharmacological, and toxicological studies on plants in the genus Macleaya. Plants from the genus of Macleaya provide a source of bioactive compounds, primarily alkaloids, with remarkable diversity and complex architectures, thereby having attracted attention from researchers. To date, 291 constituents have been identified and/or isolated from this group. These purified compounds and/or crude extract possess antitumor, anti-inflammatory, insecticidal, and antibacterial activities in addition to certain potential toxicities. Macleaya species hold potential for medicinal applications. However, despite the pharmacological studies on these plants, the mechanisms underlying the biological activities of active ingredients derived from Macleaya have not been thoroughly elucidated to date. Additionally, there is a need for research focusing on in vivo medical effects of Macleaya compounds and, eventually, for clinical trials.

Molecular targets and anticancer potential of sanguinarine-a benzophenanthridine alkaloid

BACKGROUND

Cancer is an enormous global health burden, and should be effectively addressed with better therapeutic strategies. Currently, over 60% of the clinically approved anticancer agents are either directly isolated from natural sources or are modified from natural lead molecules. Sanguinarine (SNG), a quaternary benzophenanthridine alkaloid has gained increasing attention in recent years as a potential anticancer agent.

PURPOSE

There is a large untapped source of phytochemical-based anticancer agents remaining to be explored. This review article aims to recapitulate different anticancer properties of SNG, and describes some of the molecular targets involved in exerting its effect. It also depicts the pharmacokinetic and toxicological properties of SNG, two parameters important in determining the druggability of a molecule.

METHODS

Numerous in vivo and in vitro published studies have signified the anticancer properties of SNG. In order to collate and decipher these properties, an extensive literature search was conducted in PubMed, ScienceDirect, and Scopus using keywords followed by the evaluation of the relevant articles where the relevant reports are integrated and analyzed.

RESULTS

Apart from inducing cell death, SNG inhibits pro-tumorigenic processes such as invasion, angiogenesis, and metastasis in different cancers. Moreover, SNG has been shown to synergistically enhance the sensitivity of several chemotherapeutic agents and is effective against a variety of multi-drug resistant cancers.

Carcinogenic potential of sanguinarine, a phytochemical used in 'therapeutic' black salve and mouthwash

Black salves are escharotic skin cancer therapies in clinical use since the mid 19th century. Sanguinaria canadensis, a major ingredient of black salve formulations, contains a number of bioactive phytochemicals including the alkaloid sanguinarine. Despite its prolonged history of clinical use, conflicting experimental results have prevented the carcinogenic potential of sanguinarine from being definitively determined. Sanguinarine has a molecular structure similar to known polyaromatic hydrocarbon carcinogens and is a DNA intercalator. Sanguinarine also generates oxidative and endoplasmic reticulum stress resulting in the unfolded protein response and the formation of 8-hydroxyguanine genetic lesions. Sanguinarine has been the subject of contradictory in vitro and in vivo genotoxicity and murine carcinogenesis test results that have delayed its carcinogenic classification. Despite this, epidemiological studies have linked mouthwash that contains sanguinarine with the development of oral leukoplakia. Sanguinarine is also proposed as an aetiological agent in gallbladder carcinoma. This literature review investigates the carcinogenic potential of sanguinarine. Reasons for contradictory genotoxicity and carcinogenesis results are explored, knowledge gaps identified and a strategy for determining the carcinogenic potential of sanguinarine especialy relating to black salve are discussed. As patients continue to apply black salve, especially to skin regions suffering from field cancerization and skin malignancies, an understanding of the genotoxic and carcinogenic potential of sanguinarine is of urgent clinical relevance.

Sanguinarine and Its Role in Chronic Diseases

The use of natural products derived from plants as medicines precedes even the recorded human history. In the past few years there were renewed interests in developing natural compounds and understanding their target specificity for drug development for many devastating human diseases. This has been possible due to remarkable advancements in the development of sensitive chemistry and biology tools. Sanguinarine is a benzophenanthridine alkaloid derived from rhizomes of the plant species Sanguinaria canadensis. The alkaloid can exist in the cationic iminium and neutral alkanolamine forms. Sanguinarine is an excellent DNA and RNA intercalator where only the iminium ion binds. Both forms of the alkaloid, however, shows binding to functional proteins like serum albumins, lysozyme and hemoglobin. The molecule is endowed with remarkable biological activities and large number of studies on its various activities has been published potentiating its development as a therapeutic agent particularly for chronic human diseases like cancer, asthma, etc. In this article, we review the properties of this natural alkaloid, and its diverse medicinal applications in relation to how it modulates cell death signaling pathways and induce apoptosis through different ways, its utility as a therapeutic agent for chronic diseases and its biological effects in animal and human models. These data may be useful to understand the therapeutic potential of this important and highly abundant alkaloid that may aid in the development of sanguinarine-based therapeutic agents with high efficacy and specificity.

Anticancer potential of sanguinarine for various human malignancies

Sanguinarine (Sang) - a benzophenanthridine alkaloid extracted from Sanguinaria canadensis - exhibits antioxidant, anti-inflammatory, proapoptotic and growth inhibitory activities on tumor cells of various cancer types as established by in vivo and in vitro studies. Although the underlying mechanism of Sang antitumor activity is yet to be fully elucidated, Sang has displayed multiple biological effects, which remain to suggest its possible use in plant-derived treatments of human malignancies. This review covers the anticancer abilities of Sang including inhibition of aberrantly activated signal transduction pathways, induction of cell death and inhibition of cancer cell proliferation. It also highlights Sang-mediated inhibition of angiogenesis, inducing the expression of tumor suppressors, sensitization of cancer cells to standard chemotherapeutics to enhance their cytotoxic effects, while addressing the present need for further pharmacokinetic-based studies.

Effect of bafilomycin and NAADP on membrane-associated ATPases and respiration of isolated mitochondria of the murine Nemeth-Kellner lymphoma

The goal of the study was to estimate the effect of a selective V-type H⁺ -ATPase inhibitor bafilomycin A1 and nicotinic acid adenine dinucleotide phosphate (NAADP) on energetic processes in NK/Ly cell by directly measuring the respiration of isolated mitochondria and ATPase activities. NAADP (7 μM) increased the activity of Na⁺ /K⁺ -ATPase in the postmitochondrial fraction of NK/Ly cells, but lower concentration of NAADP decreased it (0.1 and 1 μM). The increase the activity of plasma membrane Ca²⁺ ATPase (PMCA) under NAADP application (1 and 7 μM) was observed. However, NAADP (1 μM) decreased activities of sarcoendoplasmic reticulum Ca²⁺ -ATPase (SERCA) and basal Mg²⁺ -ATPase. Bafilomycin A1 (1 μM) increased the activity of Na⁺ /K⁺ -ATPase and potentiated the effect of NAADP (1 μM) on this pump. At the same time, bafilomycin A1 (1 μM) completely prevented all effects of NAADP (1 μM) on activities of PMCA, SERCA, and basal Mg²⁺ -ATPase, confirming that these effects are dependent on acidic stores. Bafilomycin A1 or NAADP decreased respiratory and oxidative phosphorylation rates in NK/Ly mitochondria when α-ketoglutarate was used as substrate in contrast to succinate. Thus, α-ketoglutarate oxidation is more sensitive to bafilomycin A1 and NAADP influences compared with succinate oxidation. However, bafilomycin A1 + NAADP and any of these compounds separately lead to full uncoupling of mitochondria after ADP addition irrespectively to substrate used. Bafilomycin A1 affects isolated tumor mitochondria more effectively in combination with NAADP. Bafilomycin and NAADP alter some membrane-associated ATPases and inhibit respiration in mitochondria of the Nemeth-Kellner lymphoma.

SIGNIFICANCE OF RESEARCH PARAGRAPH

Bafilomycin A1 potentiates the effect of NAADP by inhibiting the mitochondrial energetic process in lymphoma cells and activity of Na⁺ /K⁺ -ATPase. The obtained data show promising possibility to use bafilomycin A1 and NAADP as chemotherapeutic agents for lymphoma cells treatment. This is important because lymphomas are seventh most common form of cancer. Today the lymphoma mortality is 15% to 30%, whereas the effectiveness of malignant neoplasms treatment is less than 50%.

Assessment of the Cytotoxic and Apoptotic Eἀects of Chaetominine in a Human Leukemia Cell Line

Chaetominine is a quinazoline alkaloid originating from the endophytic fungus Aspergillus fumigatus CY018. In this study, we showed evidence that chaetominine has cytotoxic and apoptotic effects on human leukemia K562 cells and investigated the pathway involved in chaetominine-induced apoptosis in detail. Chaetominine inhibited K562 cell growth, with an IC50 value of 35 nM, but showed little inhibitory effect on the growth of human peripheral blood mononuclear cells. The high apoptosis rates, morphological apoptotic features, and DNA fragmentation caused by chaetominine indicated that the cytotoxicity was partially caused by its pro-apoptotic effect. Under chaetominine treatment, the Bax/Bcl-2 ratio was upregulated (from 0.3 to 8), which was followed by a decrease in mitochondrial membrane potential, release of cytochrome c from mitochondria into the cytosol, and stimulation of Apaf-1. Furthermore, activation of caspase-9 and caspase-3, which are the main executers of the apoptotic process, was observed. These results demonstrated that chaetominine induced cell apoptosis via the mitochondrial pathway. Chaetominine inhibited K562 cell growth and induced apoptotic cell death through the intrinsic pathway, which suggests that chaetominine might be a promising therapeutic for leukemia.

Chelidonine induces mitotic slippage and apoptotic-like death in SGC-7901 human gastric carcinoma cells

The aim of the present study was to investigate the effect of chelidonine on mitotic slippage and apoptotic-like death in SGC-7901 human gastric cancer cells. The MTT assay was performed to detect the antiproliferative effect of chelidonine. Following treatment with chelidonine (10 µmol/l), the ultrastructure changes in SGC-7901, MCF-7 and HepG2 cells were observed by transmission electron microscopy. The effects of chelidonine on G2/M phase arrest and apoptosis of SGC-7901 cells were determined by flow cytometry. Indirect immunofluorescence assay and laser scanning confocal microscopy (LSCM) were used to detect the phosphorylation level of histone H3 (Ser10) and microtubule formation was detected using LSCM following immunofluorescent labeling. Subsequent to treatment with chelidonine (10 µmol/l), expression levels of mitotic slippage-associated proteins, including BUB1 mitotic checkpoint serine/threonine kinase B (BubR1), cyclin-dependent kinase 1 (Cdk1) and cyclin B1, and apoptosis-associated protein, caspase-3 were examined by western blotting at 24, 48 and 72 h. The half maximal inhibitory concentration of chelidonine was 23.13 µmol/l over 48 h and chelidonine induced G2/M phase arrest of cells. The phosphorylation of histone H3 at Ser10 was significantly increased following treatment with chelidonine for 24 h, indicating that chelidonine arrested the SGC-7901 cells in the M phase. Chelidonine inhibited microtubule polymerization, destroyed microtubule structures and induced cell cycle arrest in the M phase. Giant cells were observed with multiple micronuclei of varying sizes, which indicated that following a prolonged arrest in the M phase, the cells underwent mitotic catastrophe. Western blotting demonstrated that the protein expression levels of BubR1, cyclin B1 and Cdk1 decreased significantly between 48 and 72 h. Low expression levels of BubR1 and inactivation of the cyclin B1-Cdk1 complex results in the cells being arrested at mitosis and leads to mitotic slippage. In addition, apoptotic morphological changes in multinucleated cells were observed, the apoptosis rates increased gradually with administration of chelidonine in a time-dependent manner and the protein levels of caspase-3 increased significantly between 24 and 72 h. Thus, chelidonine induces mitotic slippage, and apoptotic-like death occurs in SGC-7901 cells undergoing mitotic catastrophe. Gastric cancer is a common malignancy, and ranks second in overall cancer-associated mortalities worldwide. The present study demonstrated that chelidonine induces M phase arrest and mitotic slippage of SGC-7901 human gastric carcinoma cells via downregulating the expression of BubR1, Cdk1 and cyclin B1 proteins. With the prolongation of chelidonine treatment, the giant cells with multiple micronuclei underwent mitotic slippage and were maintained in the G1 phase and did not survive. A number of multinucleated cells underwent apoptosis via a caspase-dependent signaling pathway. The current study proposes that chelidonine induces mitotic slippage and apoptotic-like death of SGC-7901 cells.

Increased μ-Calpain Activity in Blasts of Common B-Precursor Childhood Acute Lymphoblastic Leukemia Correlates with Their Lower Susceptibility to Apoptosis

Childhood acute lymphoblastic leukemia (ALL) blasts are characterized by inhibited apoptosis promoting fast disease progress. It is known that in chronic lymphocytic and acute myeloid leukemias the reduced apoptosis is strongly related with the activity of calpain-calpastatin system (CCS) composed of cytoplasmic proteases--calpains--performing the modulatory proteolysis of key proteins involved in cell proliferation and apoptosis, and of their endogenous inhibitor--calpastatin. Here, the CCS protein abundance and activity was for the first time studied in childhood ALL blasts and in control bone marrow CD19+ B cells by semi-quantitative flow cytometry and western blotting of calpastatin fragments resulting from endogenous calpain activity. Significantly higher μ-calpain (CAPN1) gene transcription, protein amounts and activity (but not those of m-calpain), with calpastatin amount and transcription of its gene (CAST) greatly varying were observed in CD19(+) ALL blasts compared to control cells. Significant inverse relation between the amount/activity of calpain and spontaneous apoptosis was noted. Patients older than 10 years (considered at higher risk) displayed increased amounts and activities of blast calpain. Finally, treatment of blasts with the tripeptide calpain inhibitors II and IV significantly and in dose-dependent fashion increased the percentage of blasts entering apoptosis. Together, these findings make the CCS a potential new predictive tool and therapeutic target in childhood ALL.

Multiple mechanisms of cell death induced by chelidonine in MCF-7 breast cancer cell line

In a preliminary study screening anti-proliferative natural alkaloids, a very potent benzophenanthridine, chelidonine showed strong cytotoxicity in cancer cells. While several modes of death have been identified, most of anti-cancer attempts have focused on stimulation of cells to undergo apoptosis. Chelidonine seems to trigger multiple mechanisms in MCF-7 breast cancer cells. It induces both apoptosis and autophagy modes of cell death in a dose dependent manner. Alteration of expression levels of bax/bcl2, and dapk1a by increasing concentration of chelidonine approves switching the death mode from apoptosis induced by very low to autophagy by high concentrations of this compound. On the other hand, submicromolar concentrations of chelidonine strongly suppressed telomerase at both enzyme activity and hTERT transcriptional level. Long exposure of the cells to 50 nanomolar concentration of chelidonine considerably accelerated senescence. Altogether, chelidonine may provide a promising chemistry from nature to treat cancer.

Chelerythrine induces reactive oxygen species-dependent mitochondrial apoptotic pathway in a murine T cell lymphoma

Chelerythrine is a well-known protein kinase C inhibitor and potential antiproliferative and antitumor pharmacological agent. Chelerythrine inhibits/suppresses the HSF1 phosphorylation by inhibiting PKC and blocks the nuclear migration and subsequent synthesis of hsp70 leading to reduced cell viability and activation of apoptotic machinery. Chelerythrine is also known to enhance the production of reactive oxygen intermediate that is strong activator of apoptosis in high concentration. Therefore, the present study intended to investigate the role of chelerythrine-induced reactive oxygen intermediate on the viability and apoptosis of Dalton's lymphoma cells. Enhanced production of reactive oxygen species in Dalton's lymphoma (DL) cells was observed upon treatment of chelerythrine only which was seen completely abolished on treatment of mitochondrial complex inhibitors rotenone and malonate, and anti-oxidant, N-acetyl-L-cysteine. Increased number of DL cells undergoing apoptosis, as observed by fluorescent microscopy and flow cytometry analysis, in chelerythrine only-treated group was seen that was significantly inhibited on treatment of mitochondrial complex inhibitors and anti-oxidants. Staurosporine, on the other hand, does not lead to enhanced production of reactive oxygen intermediate in DL cells.

Amitozyn impairs chromosome segregation and induces apoptosis via mitotic checkpoint activation

Amitozyn (Am) is a semi-synthetic drug produced by the alkylation of major celandine (Chelidonium majus L.) alkaloids with the organophosphorous compound N,N'N'-triethylenethiophosphoramide (ThioTEPA). We show here that the treatment of living cells with Am reversibly perturbs the microtubule cytoskeleton, provoking a dose-dependent cell arrest in the M phase. Am changed the dynamics of tubulin polymerization in vitro, promoted the appearance of aberrant mitotic phenotypes in HeLa cells and induced apoptosis by the activation of caspase-9, caspase-3 and PARP, without inducing DNA breaks. Am treatment of HeLa cells induced changes in the phosphorylation of the growth suppressor pRb that coincided with maximum mitotic index. The dose-dependent and reversible anti-proliferative effect of Am was observed in several transformed cell lines. Importantly, the drug was also efficient against multidrug-resistant, paclitaxel-resistant or p53-deficient cells. Our results thus open the way to further pre-clinical evaluation of Am.

Mitochondrial remodeling in cancer metabolism and survival: potential for new therapies

Mitochondria are semi-autonomous organelles that play essential roles in cellular metabolism and programmed cell death pathways. Genomic, functional and structural mitochondrial alterations have been associated with cancer. Some of those alterations may provide a selective advantage to cells, allowing them to survive and grow under stresses created by oncogenesis. Due to the specific alterations that occur in cancer cell mitochondria, these organelles may provide promising targets for cancer therapy. The development of drugs that specifically target metabolic and mitochondrial alterations in tumor cells has become a matter of interest in recent years, with several molecules undergoing clinical trials. This review focuses on the most relevant mitochondrial alterations found in tumor cells, their contribution to cancer progression and survival, and potential usefulness for stratification and therapy.

Respiration characteristics of mitochondria in parental and giant transformed cells of the murine Nemeth-Kellner lymphoma

Respiration characteristics of mitochondria of the parental and giant cells of murine NK/Ly (Nemeth-Kellner lymphoma) were studied. The giant cell-enriched ascites were obtained by serial intraperitoneal injections of vinblastine in tumour-bearing mice. Ascites containing >70% giant cells were used. Their diameter of was over 17 μm (~2800 μm(3)), while the diameter of the parental cells was 12.7 μm (1100 μm(3)). The respiration rate of mitochondria in situ was measured by oxygen consumption in intact and digitonin-permeabilized NK/Ly cells. Endogenous respiration of intact giant NK/Ly cells was three times higher compared to the parental ones, roughly in agreement with the volume change. The giant NK/Ly cells were far more resistant to permeabilization with digitonin than the parental cells, as shown by Trypan Blue and LDH (lactate dehydrogenase) release tests. After digitonin permeabilization, oxygen consumption was reduced to a minimal level (0.06 ng atom O/(s × 106 cells) in both types of cells. Addition of α-ketoglutarate or succinate to the incubation medium increased oxygen consumption in the parental cells by 46 and 164% respectively. In the giant NK/Ly cells, the corresponding increases were 164 and 276%. Addition of ADP to α-ketoglutarate- or succinate-supplemented medium further stimulated oxygen consumption of the permeabilized NK/Ly cells; however, the effect of ADP was more pronounced in the giant cells. In addition, indices of respiratory control were significantly higher in the giant cells. Oligomycin suppressed considerably the respiration of the intact giant cells but had a much weaker effect on parental cells. Thus, giant NK/Ly cells possess much higher respiration rates and show tighter coupling between the respiration and oxidative phosphorylation compared with parental cells.

Activity of the chelerythrine, a quaternary benzo[c]phenanthridine alkaloid from Chelidonium majus L. on Dactylogyrus intermedius

Dactylogyrus intermedius is a significant monogenean parasite on the gills of cyprinid fishes and can cause severe economic losses in aquaculture and ornamental fish breeding. In the present study, bioactivity-guide fractionation was employed to identify active compound from Chelidonium majus L. against D. intermedius. In vivo anthelmintic activity of petroleum ether, ethyl acetate, chloroform, and n-butanol extracts of C. majus were tested. Among them, only the n-butanol extract exhibited promising anthelmintic efficacy, and therefore subjected to the further isolation and purification using various chromatographic techniques. A compound showing potent activity was obtained and identified by hydrogen, carbon-13 nuclear magnetic resonance spectrum and electron ionization mass spectrometry as chelerythrine. In vivo anthelmintic efficacy tests exhibited that chelerythrine was 100% effective against D. intermedius at a concentration of 1.60 mg L(-1), with LC(50) values of 0.68 mg L(-1) after 48 h of exposure. The 48-h LC(50) value (acute toxicity tests) of chelerythrine was found to be 3.59 mg L(-1) for grass carp. These results provided evidence that chelerythrine can be selected as a lead compound for the development of new drugs against D. intermedius.

Benzo[c]phenanthridine alkaloids exhibit strong anti-proliferative activity in malignant melanoma cells regardless of their p53 status

BACKGROUND

Search for new substances with antiproliferative activity towards melanoma cells is important since malignant melanoma is notoriously resistant to conventional chemotherapy. Benzo[c]phenanthridine alkaloids (BAs) are natural products with significant anti-proliferative activities, therefore they are considered as agents promising for cancer therapy.

OBJECTIVES

The effects of five BAs (sanguinarine, chelerythrine, chelidonine, sanguilutine, and chelilutine) on human malignant melanoma cell lines were compared. The study focused on BAs effects on DNA, anti-apoptotic and p53 protein levels; and the involvement of p53 in cellular responses to alkaloids treatment.

METHODS

Melanoma cell lines, two wild types and two with dysfunctional p53 derived from one of them were used. The mechanism of anti-proliferative and pro-apoptotic effects and the effect on DNA was investigated using MTT assay, flow cytometry, Western blot analysis, fluorescence and electron microscopy.

RESULTS

All tested alkaloids exhibit strong anti-proliferative activity. CHL, CHE and SA induced apoptosis, which was probably mediated by decreasing levels of anti-apoptotic proteins (Bcl-xL, Mcl-1, XIAP) and was accompanied by mitochondrial membrane potential decrease as well as caspase-3 and PARP cleavage. Although all alkaloids caused DNA damage, which was demonstrated by induction of H2AX phosphorylation, none of the tested alkaloids stabilised p53 and their toxicity in cells with non-functional p53 was comparable to wild type cells.

CONCLUSION

Despite the profound similarity of BAs molecular structures, it is clear that the mechanism of cell death induction is different for each alkaloid. Our results indicate that BAs could be effective in malignant melanoma treatment, including tumours which have lost wild type p53.

Sanguinarine cytotoxicity on mouse melanoma K1735-M2 cells--nuclear vs. mitochondrial effects

Sanguinarine (SANG) is an alkaloid recognized to have anti-proliferative activity against various human tumour cell lines. No data is available on the susceptibility of advanced malignant melanoma to SANG, although this disease has a very poor prognosis if not detected in time due to the resistance to conventional chemotherapy. The present work was designed to study the nuclear and mitochondrial involvement in the pro-apoptotic effect of SANG in an invasive mouse melanoma cell line. The results obtained show that SANG is primarily accumulated by the cell nuclei, causing inhibition of cell proliferation and inducing cell death, as confirmed by an increase in sub-G1 peaks. At low concentrations, SANG induces mitochondrial depolarization in a sub-population of melanoma cells, which also generally displayed strong nuclear labelling of phosphorylated histone H2AX. Western blotting revealed an increase in p53, but not Bax protein, in both whole-cell extracts and in mitochondrial fractions. Isolated hepatic mitochondrial fractions revealed that SANG affects the mitochondrial respiratory chain, and has dual effects on mitochondrial calcium loading capacity. We suggest that SANG is able to induce apoptosis in metastatic melanoma cells. The knowledge of mitochondrial vs. nuclear effects of SANG is important in the development of this promising compound for clinical use against aggressive melanoma.