Antineoplastic activity of the thiazolo[5,4-b]quinoline derivative D3CLP in K-562 cells is mediated through effector caspases activation

Concept of Hybrid Drugs and Recent Advancements in Anticancer Hybrids

Cancer is a complex disease, and its treatment is a big challenge, with variable efficacy of conventional anticancer drugs. A two-drug cocktail hybrid approach is a potential strategy in recent drug discovery that involves the combination of two drug pharmacophores into a single molecule. The hybrid molecule acts through distinct modes of action on several targets at a given time with more efficacy and less susceptibility to resistance. Thus, there is a huge scope for using hybrid compounds to tackle the present difficulties in cancer medicine. Recent work has applied this technique to uncover some interesting molecules with substantial anticancer properties. In this study, we report data on numerous promising hybrid anti-proliferative/anti-tumor agents developed over the previous 10 years (2011–2021). It includes quinazoline, indole, carbazole, pyrimidine, quinoline, quinone, imidazole, selenium, platinum, hydroxamic acid, ferrocene, curcumin, triazole, benzimidazole, isatin, pyrrolo benzodiazepine (PBD), chalcone, coumarin, nitrogen mustard, pyrazole, and pyridine-based anticancer hybrids produced via molecular hybridization techniques. Overall, this review offers a clear indication of the potential benefits of merging pharmacophoric subunits from multiple different known chemical prototypes to produce more potent and precise hybrid compounds. This provides valuable knowledge for researchers working on complex diseases such as cancer.

In-silico Pharmacokinetic and Affinity Studies of Piperazine/Morpholine Substituted Quinolines in Complex with GAK as Promising Anti-HCV Agent

Piperazine/morpholine derivatives of quinoline substituted at positions C-3, C-6 and C-8 has been previously prepared by SNAr reactions of 3,6,8-tribromoquinoline (1) under microwave or conventional heating reaction conditions. In this study, we evaluated binding interactions between the piperazine/morpholine substituted quinolines and its highly-likely receptor, Cyclin G associated kinase (GAK) involved in hepatitis C virus (HCV) entry into host cells, via docking, molecular dynamics (MD), thermodynamic and pharmacokinetics computations in order to select a possible lead compound, which may be used for lead-optimization in our future studies to develop novel drug candidates against HCV infections. 372 nsec MD simulations followed by MM-PBSA thermodynamic computations revealed that compound 23 ([Formula: see text]= 0.08[Formula: see text]nM) possesses the greatest potential to inhibit GAK. Pharmacokinetics computations suggest that compound 23 is a drug-like molecule as it conforms to the Lipinski filter. We determined that compound 23 could be a lead-like molecule for peripheric and cerebral HCV infections.

Quinoline anticancer agents active on DNA and DNA-interacting proteins: From classical to emerging therapeutic targets

Quinoline is one of the most important and versatile nitrogen heterocycles embodied in several biologically active molecules. Within the numerous quinolines developed as antiproliferative agents, this review is focused on compounds interfering with DNA structure or with proteins/enzymes involved in the regulation of double helix functional processes. In this light, a special focus is given to the quinoline compounds, acting with classical/well-known mechanisms of action (DNA intercalators or Topoisomerase inhibitors). In particular, the quinoline drugs amsacrine and camptothecin (CPT) have been studied as key lead compounds for the development of new agents with improved PK and tolerability properties. Moreover, notable attention has been paid to the quinoline molecules, which are able to interfere with emerging targets involved in cancer progression, as G-quadruplexes or the epigenetic ones (e.g.: histone deacetylase, DNA and histones methyltransferase). The antiproliferative and the enzymatic inhibition data of the reviewed compounds have been analyzed. Furthermore, concerning the SAR (structure-activity relationship) aspects, the most recurrent ligand-protein interactions are summarized, underling the structural requirements for each kind of mechanism of action.

Have molecular hybrids delivered effective anti-cancer treatments and what should future drug discovery focus on?

INTRODUCTION

Cancer continues to be a big threat and its treatment is a huge challenge among the medical fraternity. Conventional anti-cancer agents are losing their efficiency which highlights the need to introduce new anti-cancer entities for treating this complex disease. A hybrid molecule has a tendency to act through varied modes of action on multiple targets at a given time. Thus, there is the significant scope with hybrid compounds to tackle the existing limitations of cancer chemotherapy.

AREA COVERED

This perspective describes the most significant hybrids that spring hope in the field of cancer chemotherapy. Several hybrids with anti-proliferative/anti-tumor properties currently approved or in clinical development are outlined, along with a description of their mechanism of action and identified drug targets.

EXPERT OPINION

The success of molecular hybridization in cancer chemotherapy is quite evident by the number of molecules entering into clinical trials and/or have entered the drug market over the past decade. Indeed, the recent advancements and co-ordinations in the interface between chemistry, biology, and pharmacology will help further the advancement of hybrid chemotherapeutics in the future.List of abbreviations: Deoxyribonucleic acid, DNA; national cancer institute, NCI; peripheral blood mononuclear cells, PBMC; food and drug administration, FDA; histone deacetylase, HDAC; epidermal growth factor receptor, EGFR; vascular endothelial growth factor receptor, VEGFR; suberoylanilide hydroxamic acid, SAHA; farnesyltransferase inhibitor, FTI; adenosine triphosphate, ATP; Tamoxifen, TAM; selective estrogen receptor modulator, SERM; structure activity relationship, SAR; estrogen receptor, ER; lethal dose, LD; half maximal growth inhibitory concentration, GI₅₀; half maximal inhibitory concentration, IC₅₀.

Decision making for promising quinoline-based anticancer agents through combined methodology

During the development of effective drugs for the treatment of cancer, one of the most important tasks is to identify effective drug candidates having maximum antiproliferation and minimum side effects. This paper considers the problem of selecting the most promising anticancer agents, showing inhibition at low IC50 concentration and low releasing lactate dehydrogenase percentage (cytotoxicity). Recently, we prepared quinoline analogs bearing different functional groups and determined their anticancer potential against the HeLa, C6, and HT29 cancer cell lines using different anticancer assays. Experimentally, seven quinoline derivatives consisting of different substituents were determined as promising anticancer agents. We propose a multicriteria recommendation method to identify the most promising anticancer agents against all tested cell lines with an accurate prediction algorithm according to the available input data. A multicriteria decision-making methodology (MCDM) was used for the solution of the relevant problem in this study. Both the experimental results and MCDM method indicated that 5,7-dibromo-8-hydroxyquinoline (2) and 6,8-dibromo-1,2,3,4-tetrahydroquinoline (6) are the most promising anticancer agents against the HeLa, HT29, and C6 cell lines.

Application of the Povarov Reaction in Biaryls under Iron Catalysis for the General Synthesis of Dibenzo[a,c]Acridines

A modified Povarov reaction involving 2'-alkynylbiaryl-2-carbaldehydes and aryl amines with tandem oxidation was performed using catalytic FeCl₃. The outcome was an efficient general synthesis of dibenzo[a,c]acridines with moderate to high yields. This method offers simplicity in the preparation of substrates, diverse substrate scope, and high atom economy. The generality of the protocol was verified by synthesizing a tribenzo[a,c,h]acridine derivative. Photophysical properties of the synthesized compounds were also studied. The compounds absorb UV light typically in the range 230-330 nm and emit in the visible range of 400-420 nm.

Synthesis and evaluation of anticancer activity of new 9-acridinyl amino acid derivatives

A series of eleven 9-acridinyl amino acid derivatives were synthesized using a two-step procedure. Cytotoxicity was tested on the K562 and A549 cancer cell lines and normal diploid cell line MRC5 using the MTT assay. Compounds 6, 7, 8 and 9 were the most active, with IC₅₀ values comparable to or lower than that of chemotherapeutic agent amsacrine. 8 and 9 were especially effective in the A549 cell line (IC₅₀ ≈ 6 μM), which is of special interest since amsacrine is not sufficiently active in lung cancer patients. Cell cycle analysis revealed that 7 and 9 caused G2/M block, amsacrine caused arrest in the S phase, while 6 and 8 induced apoptotic cell death independently of the cell cycle regulation. In comparison to amsacrine, 6, 7, 8, and 9 showed similar inhibitory potential towards topoisomerase II, whereas only 7 showed DNA intercalation properties. In contrast to amsacrine, 6, 7, 8 and 9 showed a lack of toxicity towards unstimulated normal human leucocytes.

Identification of dehydroxy isoquine and isotebuquine as promising anticancer agents targeting K+ channel

Traditional antimalarial drugs based on 4-aminoquinolines have exhibited good antiproliferative activities against human tumor cells; however, their low relative efficacy has limited their corresponding clinical uses. In order to identify new potent anticancer agents based on 4-aminoquinoline, we evaluated the antiproliferative activity of a series of dehydroxy isoquines and isotebuquines against five human cancer lines. HeLa and SKBr3 were significantly more sensitive to the action of tested quinolines than the A549, MCF-7, and PC-3 cancer lines. Compound 2h was by far the most potent derivative against four of the tested lines (except to PC3 line), exhibiting low micromolar or nanomolar IC₅₀ values superior to adriamycin reference, low toxicities on dermis human fibroblasts (LD₅₀  > 250 μM), and excellent selectivity indexes against the mentioned cancer cells. A structure-activity relationship analysis put in evidence that a pyrrolidine or morpholine moiety as N-alkyl terminal substitution and the incorporation of the extra phenyl attached to aniline ring are pharmacophore essentials for improvement the anticancer activity of the studied dehydroxy isoquines and isotebuquines. From the results, compound 2h emerged as a promising anticancer candidate for further in vitro assays against resistant-strain and in vivo studies as well as pharmacokinetic and genotoxicity studies. Mechanistic assays suggested that the most active quinoline 2h act as calcium-activated potassium channel activator.

Biological evaluation of some quinoline derivatives with different functional groups as anticancer agents

Due to a great deal of biological activities, quinoline derivatives have drawn attention for synthesis and biological activities in the search for new anticancer drug development. In this work, a variety of substituted (phenyl, nitro, cyano, N-oxide, and methoxy) quinoline derivatives (3-13) were tested in vitro for their biological activity against cancer cell lines, including rat glioblastoma (C6), human cervical cancer cells (HeLa), and human adenocarcinoma (HT29). 6-Bromo-5-nitroquinoline (4), and 6,8-diphenylquinoline (compound 13) showed the greatest antiproliferative activity as compared with the reference drug, 5-fluorouracil (5-FU), while the other compounds showed low antiproliferative activity. 6-Bromo-5-nitroquinoline (4) possesses lower cytotoxic activity than 5-FU in HT29 cell line. Due to its the apoptotic activity 6-Bromo-5-nitroquinoline (4) has the potential to cause cancer cell death.

Prolactin-induced neuroprotection against glutamate excitotoxicity is mediated by the reduction of [Ca2+]i overload and NF-κB activation

Prolactin (PRL) is a peptidic hormone that displays pleiotropic functions in the organism including different actions in the brain. PRL exerts a neuroprotective effect against excitotoxicity produced by glutamate (Glu) or kainic acid in both in vitro and in vivo models. It is well known that Glu excitotoxicity causes cell death through apoptotic or necrotic pathways due to intracellular calcium ([Ca²⁺] i) overload. Therefore, the aim of the present study was to assess the molecular mechanisms by which PRL maintains cellular viability of primary cultures of rat hippocampal neurons exposed to Glu excitotoxicity. We determined cell viability by monitoring mitochondrial activity and using fluorescent markers for viable and dead cells. The intracellular calcium level was determined by a fluorometric assay and proteins involved in the apoptotic pathway were determined by immunoblot. Our results demonstrated that PRL afforded neuroprotection against Glu excitotoxicity, as evidenced by a decrease in propidium iodide staining and by the decrease of the LDH activity. In addition, the MTT assay shows that PRL maintains normal mitochondrial activity even in neurons exposed to Glu. Furthermore, the Glu-induced intracellular [Ca²⁺]i overload was attenuated by PRL. These data correlate with the reduction found in the level of active caspase-3 and the pro-apoptotic ratio (Bax/Bcl-2). Concomitantly, PRL elicited the nuclear translocation of the transcriptional factor NF-κB, which was detected by immunofluorescence and confocal microscopy. To our knowledge, this is the first report demonstrating that PRL prevents Glu excitotoxicity by a mechanism involving the restoration of the intracellular calcium homeostasis and mitochondrial activity, as well as an anti-apoptotic action possibly mediated by the activity of NF-κB. Overall, the current results suggest that PRL could be of potential therapeutic advantage in the treatment of neurodegenerative diseases.

Recent developments in the synthesis and biological activity of acridine/acridone analogues

Many people in the world struggle with cancer or bacterial, parasitic, viral, Alzheimer's and other diseases.

Prolactin mediates neuroprotection against excitotoxicity in primary cell cultures of hippocampal neurons via its receptor

Recently it has been reported that prolactin (PRL) exerts a neuroprotective effect against excitotoxicity in hippocampus in the rat in vivo models. However, the exact mechanism by which PRL mediates this effect is not completely understood. The aim of our study was to assess whether prolactin exerts neuroprotection against excitotoxicity in an in vitro model using primary cell cultures of hippocampal neurons, and to determine whether this effect is mediated via the prolactin receptor (PRLR). Primary cell cultures of rat hippocampal neurons were used in all experiments, gene expression was evaluated by RT-qPCR, and protein expression was assessed by Western blot analysis and immunocytochemistry. Cell viability was assessed by using the MTT method. The results demonstrated that PRL treatment of neurons from primary cultures did not modify cell viability, but that it exerted a neuroprotective effect, with cells treated with PRL showing a significant increase of viability after glutamate (Glu)--induced excitotoxicity as compared with neurons treated with Glu alone. Cultured neurons expressed mRNA for both PRL and its receptor (PRLR), and both PRL and PRLR expression levels changed after the excitotoxic insult. Interestingly, the PRLR protein was detected as two main isoforms of 100 and 40 kDa as compared with that expressed in hypothalamic cells, which was present only as a 30 kDa variant. On the other hand, PRL was not detected in neuron cultures, either by western blot or by immunohistochemistry. Neuroprotection induced by PRL was significantly blocked by specific oligonucleotides against PRLR, thus suggesting that the PRL role is mediated by its receptor expressed in these neurons. The overall results indicated that PRL induces neuroprotection in neurons from primary cell cultures.

A direct synthetic route to fused tricyclic quinolones from 2,3-diaminoquinolin-4(1H)one

Fused tricyclic heterocycles are useful compounds in many areas of chemistry. In this study, 2,3-diaminoquinolin-4(1

One Pot Synthesis, Photophysical and X-ray Studies of Novel Highly Fluorescent Isoquinoline Derivatives with Higher Antibacterial Efficacy Based on the In-vitro and Density Functional Theory

Series of cyano substituted isoquinoline dyes were synthesized by one-pot multicomponent reactions (MCRs) of aldehydes, malononitrile, 6-methoxy-1,2,3,4-tetrahydro-naphthalin-1-one and ammonium acetate. Results obtained from spectroscopic (FT-IR, (1)H-NMR, (13)C-NMR, EI-MS) and elemental analysis of synthesized compounds was in agreement with their chemical structures. Structure of the compound was further conformed by X-ray crystallographic. UV-vis and fluorescence spectroscopy measurements provided that all compounds are good absorbent and fluorescent. Fluorescence polarity study demonstrated that these compounds were sensitive to the polarity of the microenvironment provided by different solvents. In addition, spectroscopic and physicochemical parameters, including electronic absorption, extenction coefficient, Stokes shift, oscillator strength transition dipole moment and fluorescence quantum yield were investigated in order to explore the analytical potential of synthesized compounds. The anti-bacterial activity of these compounds were first studied in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria. The minimum inhibitory concentration was then determined with the reference of standard drug chloramphenicol. The results displayed that compound 3 was better inhibitors of both types of the bacteria (Gram-positive and Gram-negative) than chloramphenicol. Furthermore, quantum chemistry calculations using DFT/6-31-G* level of theory confirm the results. Dipole moment and frontier molecular orbitals were also investigated.

Acridine and its derivatives: a patent review (2009 - 2013)

INTRODUCTION

Acridine derivatives have been extensively explored as potential therapeutic agents for the treatment of a number of diseases, such as cancer, Alzheimer's, and bacterial and protozoan infections. Their mode of action is mainly attributed to DNA intercalation and the subsequent effects on the biological processes linked to DNA and its related enzymes.

AREA COVERED

This review covers the relevant efforts in developing acridine derivatives with enhanced therapeutic potency and selectivity and as fluorescent materials, with particular focus on the newly patented acridine derivatives in 2009 - 2013, acridine drugs in clinical trials and preclinical studies, and other new derivatives that emerged in 2009 - 2013.

EXPERT OPINION

Thousands of acridines with therapeutic and biological activities or with photochemical properties have been developed. In addition, to modify the position and the nature of the substituent on the acridine core, more attention may be paid to the development of azaacridine or other heteroatom-substituted acridine derivatives and their synthesis methods to broaden the application of acridine derivatives. In cancer chemotherapy, the mode of action of acridine derivatives needs to be further studied. Efficient methods for identification and optimization of acridine derivatives to localize at the sites of disease need to be further developed. Moreover, acridine drugs may be combined with such bioactive agents as DNA repair proteins inhibitors to overcome tumor resistance and improve outcomes.

A review on anticancer potential of bioactive heterocycle quinoline

The advent of Camptothecin added a new dimension in the field anticancer drug development containing quinoline motif. Quinoline scaffold plays an important role in anticancer drug development as their derivatives have shown excellent results through different mechanism of action such as growth inhibitors by cell cycle arrest, apoptosis, inhibition of angiogenesis, disruption of cell migration, and modulation of nuclear receptor responsiveness. The anti-cancer potential of several of these derivatives have been demonstrated on various cancer cell lines. In this review we have compiled and discussed specifically the anticancer potential of quinoline derivatives, which could provide a low-height flying bird's eye view of the quinoline derived compounds to a medicinal chemist for a comprehensive and target oriented information for development of clinically viable anticancer drugs.

Magnolia dealbata seeds extract exert cytotoxic and chemopreventive effects on MDA-MB231 breast cancer cells

CONTEXT

Cancer prevention remains a high priority for the scientific world. Magnolia dealbata Zucc (Magnoliaceae), a Mexican endemic species, is used for the empirical treatment of cancer.

OBJECTIVE

To evaluate the cytotoxic and cancer chemopreventive effects of an ethanol extract of Magnolia dealbata seeds (MDE).

MATERIALS AND METHODS

The cytotoxic effect of MDE, at concentrations ranging from 1 to 200 µg/ml, on human cancer cells and human nontumorigenic cells was evaluated using the MTT assay for 48 h. The apoptotic activities of MDE 25 μg/ml on MDA-MB231 breast cancer cells were evaluated using the TUNEL assay and the detection of caspase 3 using immunofluorescence analysis for 48 h, each. The chemopreventive effect was evaluated by administrating different doses of MDE, between 1 and 50 mg/kg, injected intraperitoneally daily into athymic mice which were implanted with MDA-MB231 cells during 28 days. The growth and weight of tumors were measured.

RESULTS

MDE showed cytotoxic effects on MDA-MB231 cells (IC₅₀ = 25 µg/ml) and exerted pro-apoptotic activities as determined by DNA fragmentation in MDA-MB231 cells. MDE 25 µg/ml also induces the activation of caspase 3 in MDA-MB231 cells. These results suggest that Magnolia dealbata may be an optimal source of the bioactive compounds: honokiol (HK) and magnolol (MG). MDE 50 mg/kg i.p. exerted chemopreventive effects by inhibiting the growth of MDA-MB231 tumor by 75% in athymic mice, compared to the control group.

CONCLUSIONS

MDE exerts cytotoxic, apoptotic and chemopreventive activities on MDA-MB231 human cancer cells.

Molecular mechanisms involved in the cytotoxicity induced by coumarins from Calophyllum brasiliense in K562 leukaemia cells

OBJECTIVES

The aim of this study was to determine the cellular and molecular mechanisms of cell death induced by mammea A/BA and A/BB (3 : 1) on K562 cells.

METHODS

These compounds were isolated from Calophyllum brasiliense and its cytotoxicity was tested using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell death was evaluated by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and immunocytofluorescence of active caspase-3. Genotoxicity was tested using comet assay. Lastly, a chemoinformatic analysis was performed with Osiris-Molinspiration software.

KEY FINDINGS

The mixture of mammea A/BA and A/BB (3 : 1) showed cytotoxic activity against K562 cells (IC50 = 43.5 μm). TUNEL positive cells and active caspase-3 were detected after treatment. Genotoxicity of mammea A/BA and A/BB on K562 was detected since first hour of treatment. Additionally, mammea A/BA and A/BB were found to be in compliance with Lipinski 'rule of 5' suggesting that they possess strong potential of druglikeness.

CONCLUSIONS

The overall results confirm and extend the knowledge about coumarins as an important resource of antitumor drugs, and indicate that these compounds could be used in further preclinical studies against leukaemia.

Synthesis and anticancer activity of some novel trifluoromethylquinolines carrying a biologically active benzenesulfonamide moiety

Several trifluoromethylquinoline derivatives containing a biologically active benzenesulfonamide moiety 2-14, 16, urea derivatives 15, 17, 4-isothiocyanate 18 and the corresponding carbamimidothioic acid derivatives 19-30, were synthesized from the strategic starting material 4-chloro-7-trifluoromethylquinoline 1. The structures of the newly synthesized compounds were elucidated on the basis of elemental and spectral analyses. All the prepared compounds were evaluated for their in vitro anticancer activity against various cancer cell lines. Most of the synthesized compounds showed good activity, especially compound 15 which exhibited higher activity than the reference drug doxorubicin. In order to suggest the mechanism of action for their cytotoxic activity, molecular docking for all synthesized compounds was done on the active site of PI3K and good results were obtained.

In vitro drug metabolism testing using blood-monocyte derivatives

INTRODUCTION

Monocytes and their cell derivatives can participate in drug metabolism. These cells express different Phase-I or -II drug metabolizing enzymes and can be differentiated into neo-hepatocytes (NeoHep) and represent a promising alternative strategy to test drug metabolism. This is particularly useful as primary human hepatocytes (PHH), are difficult to obtain and maintain in culture.

AREAS COVERED

The authors analyze the use of blood monocytes and their derivatives for the study of drug metabolism. They also compare them to the in vitro ability of cells from different sources including: PHH, immortalized hepatocytes, tumor cell lines and NeoHep.

EXPERT OPINION

The use of monocytes, macrophages, dendritic or Kupffer cells, to test drug metabolism, has serious limitations because these cells express lower levels of cytochrome P450 enzymes than PHH. The best available option, to replace PHH, have been tumor cell lines such as HepaRG, as well as immortalized hepatocytes from adult or fetal sources. Monocyte-derived NeoHep cells are novel and easily accessible cells, which express many drug metabolizing enzymes at levels comparable to PHH. These cells allow drug evaluation under a diverse genetic background. While these cells are in the early stages of evaluation and do need to be examined more thoroughly, they constitute a promising new tool for in vitro drug testing.

Novel synthetic acridine derivatives as potent DNA-binding and apoptosis-inducing antitumor agents

Acridine derivatives have been explored as DNA-binding anticancer agents. Some derivatives show undesired pharmacokinetic properties and new derivatives need to be explored. In this work, a series of novel acridine analogues were synthesized by modifying previously unexplored linkers between the acridine and benzene groups and their antiproliferative activity and the DNA-binding ability were evaluated. Among these derivatives, compound 5c demonstrated DNA-binding capability and topoisomerase I inhibitory activity. In K562 cell lines, 5c induced apoptosis through mitochondria-dependent intrinsic pathways. These data suggested that compound 5c and other acridine derivatives with modified linkers between the acridine and benzene groups might be potent DNA-binding agents.

Kaempferitrin induces apoptosis via intrinsic pathway in HeLa cells and exerts antitumor effects

ETHNOPHARMACOLOGICAL RELEVANCE

Justicia spicigera is used for the empirical treatment of cervical cancer in Mexico. Recently, we showed that Justicia spicigera extracts exerted cytotoxic and antitumoral effects and the major component of this extract was kaempferitrin (KM).

MATERIALS AND METHODS

The cytotoxic and apoptotic effect of KM on human cancer cells and human nontumorigenic cells were evaluated using MTT and TUNEL assays, and Annexin V/Propidium iodide detection by flow cytometry. The effect of KM on cell cycle was analyzed by flow cytometry with propidium iodide. The apoptotic and cell cycle effects were also evaluated by western blot analysis. Also, different doses of KM were injected intraperitoneally daily into athymic mice bearing tumors of HeLa cells during 32 days. The growth and weight of tumors were measured.

RESULTS

KM induces high cytotoxic effects in vitro and in vivo against HeLa cells. The general mechanisms by which KM induces cytotoxic effects include: cell cycle arrest in G1 phase and apoptosis via intrinsic pathway in a caspase dependent pathway. Also, KM exerts chemopreventive and antitumor effects.

CONCLUSION

KM exerts cytotoxic and antitumor effects against HeLa cells.

The antitumoral effect of the American mistletoe Phoradendron serotinum (Raf.) M.C. Johnst. (Viscaceae) is associated with the release of immunity-related cytokines

ETHNOPHARMACOLOGICAL RELEVANCE

Phoradendron serotinum is commonly used in Mexican traditional medicine for the empirical treatment of cancer. However, there are no studies regarding the antitumoral or immunomodulatory activities of Phoradendron serotinum.

MATERIALS AND METHODS

The in vivo toxicity of ethanolic extracts of Phoradendron serotinum (PSE) was evaluated in mice according to the Lorke procedure. The in vitro immunomodulatory effects of PSE were evaluated estimating the effects of PSE on the pinocytosis, NO production and lysosomal enzyme activity in murine macrophages RAW 264.7. The effects of PSE on the proliferation of murine splenocytes and NK cell activity were also assayed. The cytotoxic effects on TC-1 (lung murine cancer cells) were evaluated using the MTT assay, whereas the apoptotic effect of PSE on TC-1 cells was evaluated using TUNEL assay. Also, different doses of PSE were injected intraperitoneally daily into C57BL/6 mice bearing tumors of TC-1 cells during 25 days. The growth and weight of tumors was measured. In addition, the levels of IL-2, IL-6, IL-12, IL-23 and IFN-γ in murine serum and supernatants of K562 cell-murine splenocyte cocultures were measured.

RESULTS

PSE stimulated the proliferation, pinocytosis and lysosomal enzyme activity in murine macrophages with a similar potency than lypopolisaccharides 1 μg/ml. In addition, PSE stimulated the proliferation of murine splenocytes and induced the NK cell activity. PSE showed cytotoxic (IC(50)=1.9 μg/ml) and apoptotic effects against TC-1 cells. The LD(50) was 125 mg/kg by intraperitoneal route (i.p.) and 375 mg/kg by oral route. PSE administrated at 1, 5 and 10 mg/kg i.p. inhibited the tumor growth by 18%, 40% and 69%, respectively, in mice bearing TC-1 tumor. PSE increased the in vitro and in vivo release of IL-2, IL-6 and IFN-γ but lacked effect on IL-12 and IL-23 release.

CONCLUSIONS

Phoradendron serotinum shows moderate toxic effects in vivo, exerts cytotoxic and apoptotic effects on TC-1 cells. Phoradendron serotinum also has antitumor effects in mice bearing TC-1 tumor and induces immunomodulatory activities in vivo. The results suggest that antitumoral effects of PSE are related with the production of immunity-related cytokines.