Discovery of harmiprims, harmine-primaquine hybrids, as potent and selective anticancer and antimalarial compounds.

Although cancer and malaria are not etiologically nor pathophysiologically connected, due to their similarities successful repurposing of antimalarial drugs for cancer and vice-versa is known and used in clinical settings and drug research and discovery. With the growing resistance of cancer cells and Plasmodium to the known drugs, there is an urgent need to discover new chemotypes and enrich anticancer and antimalarial drug portfolios. In this paper, we present the design and synthesis of harmiprims, hybrids composed of harmine, an alkaloid of the ß-carboline type bearing anticancer and antiplasmodial activities, and primaquine, 8-aminoquinoline antimalarial drug with low antiproliferative activity, covalently bound via triazole or urea. Evaluation of their antiproliferative activities in vitro revealed that N-9 substituted triazole-type harmiprime was the most selective compound against MCF-7, whereas C1-substituted ureido-type hybrid was the most active compound against all cell lines tested. On the other hand, dimeric harmiprime was not toxic at all. Although spectrophotometric studies and thermal denaturation experiments indicated binding of harmiprims to the ds-DNA groove, cell localization showed that harmiprims do not enter cell nucleus nor mitochondria, thus no inhibition of DNA-related processes can be expected. Cell cycle analysis revealed that C1-substituted ureido-type hybrid induced a G1 arrest and reduced the number of cells in the S phase after 24 h, persisting at 48 h, albeit with a less significant increase in G1, possibly due to adaptive cellular responses. In contrast, N-9 substituted triazole-type harmiprime exhibited less pronounced effects on the cell cycle, particularly after 48 h, which is consistent with its moderate activity against the MCF-7 cell line. On the other hand, screening of their antiplasmodial activities against the erythrocytic, hepatic, and gametocytic stages of the Plasmodium life cycle showed that dimeric harmiprime exerts powerful triple-stage antiplasmodial activity, while computational analysis showed its binding within the ATP binding site of PfHsp90.

A miniaturized matrix solid-phase dispersion methodology (µMSPD) for determination of ß-carboline alkaloids in tobacco samples by UPLC-ESI-Q-TOF/MSE.

Alkaloids play an important role in the chemical composition of tobacco, due to their effects that have led to the global consumption of this commodity. The ß-carboline alkaloids present inhibitory action against the enzyme monoamine oxidase (MAO), which enhances the susceptibility to chemical dependence in smokers. There is a need for scientific studies to ensure the correct identification and quantification of these compounds in tobacco matrices. In this work, we present the development and validation of a microextraction analytical method for determination and quantification of the alkaloids harmaline, harmalol, harmane, harmine, norharmane, and tetrahydroharmine in natural and processed samples of tobacco, employing micro-matrix solid-phase dispersion (µMSPD), ultra-performance liquid chromatography (UPLC), and mass spectrometry (MS). The optimized µMSPD procedure employed of 0.01 g of sample, 0.1 g of Discovery® DPA-6S adsorbent, and elution with 2 mL of aqueous 1 % formic acid solution, resulting in a fast, practical, economical, and environmentally friendly technique. Validation of the methodology showed that it presented good linearity (R2 > 0.9945), satisfactory accuracy and precision (in the range from 72 ± 16 % to 109 ± 9 %), and limits of quantification (LOQ) and detection (LOD) in the ranges 0.02-1.0 µg g-1 and 0.01-0.2 µg g-1, respectively. The developed method was applied to tobacco samples, proving to be efficient for determination of ß-carboline alkaloids. The compounds harmane and norharmane were quantified in samples of fresh tobacco leaves, cured tobacco leaves, twisted tobacco, and cigarettes. Harmine was only not quantified in the cigarettes.

Rational Design and Identification of Harmine-Inspired, N-Heterocyclic DYRK1A Inhibitors Employing a Functional Genomic In Vivo Drosophila Model System.

Deregulation of dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) plays a significant role in developmental brain defects, early-onset neurodegeneration, neuronal cell loss, dementia, and several types of cancer. Herein, we report the discovery of three new classes of N-heterocyclic DYRK1A inhibitors based on the potent, yet toxic kinase inhibitors, harmine and harmol. An initial in vitro evaluation of the small molecule library assembled revealed that the core heterocyclic motifs benzofuranones, oxindoles, and pyrrolones, showed statistically significant DYRK1A inhibition. Further, the utilization of a low cost, high-throughput functional genomic in vivo model system to identify small molecule inhibitors that normalize DYRK1A overexpression phenotypes is described. This in vivo assay substantiated the in vitro results, and the resulting correspondence validates generated classes as architectural motifs that serve as potential DYRK1A inhibitors. Further expansion and analysis of these core compound structures will allow discovery of safe, more effective chemical inhibitors of DYRK1A to ameliorate phenotypes caused by DYRK1A overexpression.

Structure-activity insights of harmine targeting DNA, ROS inducing cytotoxicity with PARP mediated apoptosis against cervical cancer, anti-biofilm formation and in vivo therapeutic study.

Harmine exhibits pH dependent structural equilibrium and possesses numerous biological and pharmacological activities. Mode and mechanism of DNA binding and its cytotoxicity were studied by multiple spectroscopic, calorimetric, molecular docking and in vitro apoptotic as well as in vivo biochemical and histological studies. It exists as cationic (structure I) and decationic form (structure II) in the pH range 3.0-7.8 and 8.5-12.4, respectively, with a pKa of 8.0. Structure I at pH 6.8 binds strongly to DNA with a cooperative mode of binding of Kiω 1.03 × 106 M-1and stoichiometry of 5.0 nucleotide phosphates. Structure I stabilized DNA by 10 °C, showed85%quenching of fluorescence intensity, perturbation in circular dichroism, partial intercalation and enthalpy driven exothermic binding. While, structure II at pH 8.5 has very weak interaction with CT DNA. Cytotoxic potencies of structure I was tested on four different cancer cell lines along with normal embryonic cell. It showed maximum cytotoxicity with GI50of 20 µM, against HeLa causing several apoptotic induction abilities. Harmine exhibited G2M arrest with ROS induced effective role in PARP mediated apoptosis as well as anti-inflammatory action on HeLa cells. Harmine further presented MIC and antibiofilm activity against Staphylococcus aureus in presence of <160 and 30 µg/ml, respectively. Mice with post harmine treatment (30 mg/kg b.w., I.P.) showed maximum recovery from damaged to near normal architecture of cervical epithelial cells. This study may be of prospective use in a framework to design novel beta carboline compounds for improved therapeutic applications in future against cervical cancer. HighlightsHarmine exists in structure I and structure II forms in the pH 6.8 and 8.5with a pKa of 8.0.Structure I at pH 6.8 binds strongly to DNA compared to structure II.Structure I showed maximum cytotoxicity with GI50 of 20 µM against HeLa.ROS mediated cytotoxicitywithG2M arrest with PARP mediated apoptosis was studied.Harmine (30µg/ml) exhibited antibiofilm activity against Staphylococcus aureus.Post harmine dose (30 mg/kg b.w., I.P.) in mice showed recovery of cervical epithelial cells.Communicated by Ramaswamy H. Sarma.

The effect of onion and garlic on non-polar heterocyclic aromatic amines (α-, ß-, γ- and δ-carbolines) formation in pan-fried meat and gravy.

Thermal treatment of protein-rich food can lead to the formation of biologically active heterocyclic aromatic amines (HAAs). One of the methods to learn how to reduce the content as well as the influence of these compounds on heath is the study of factors inhibiting their synthesis. In the current investigation, the effect of onion and garlic on the formation of six possibly carcinogenic non-polar HAAs (α-, γ- and δ-carbolines) and two co-mutagenic ß-carbolines (harmane and norharmane) was evaluated by comparing their contents in meat and gravy samples obtained from pan-fried pork dishes prepared in the presence and absence of these vegetables. Carbolines were isolated from food samples by solid phase extraction. The quantitative analysis was performed by high-performance liquid chromatography with fluorescence detection. The concentrations of individual compounds in dishes prepared without added vegetables ranged from 0.02 ng g-1 (3-amino-1,4-dimethyl-5 H-pyrido(4,3-b)indole; Trp-P-1) to 10.1 ng g-1 of meat (2-amino-9 H-pyrido[2,3-b]indole; AαC). Onion (30 g/100 g of meat) and garlic (15 g/100 g of meat) lowered the total content (in meat and gravy) of the α-, δ- and γ-carbolines in the range from 52% to 87%. In contrast, onion caused an increase in the norharmane concentration both in meat and gravy. The percentage of carbolines in the gravies (assuming that their total content in meat and gravy is 100%) was higher in dishes prepared with onion and garlic than in dishes without these seasonings.

Harmine Hydrochloride Mediates the Induction of G2/M Cell Cycle Arrest in Breast Cancer Cells by Regulating the MAPKs and AKT/FOXO3a Signaling Pathways.

Breast cancer (BC) is one of the most common causes of death among women worldwide. Recently, interest in novel approaches for BC has increased by developing new drugs derived from natural products with reduced side effects. This study aimed to treat BC cells with harmine hydrochloride (HMH) to identify its anticancer effects and mechanisms. HMH treatment suppressed cell growth, migration, invasion, and colony formation in MCF-7 and MDA-MB-231 cells, regardless of the hormone signaling. It also reduced the phosphorylation of PI3K, AKT, and mTOR and increased FOXO3a expression. Additionally, HMH treatment increased p38 phosphorylation in MCF-7 cells and activated c-Jun N-terminal kinase (JNK) phosphorylation in MDA-MB-231 cells in a dose-dependent manner, where activated p38 and JNK increased FOXO3a expression. Activated FOXO3a increased the expression of p53, p21, and their downstream proteins, including p-cdc25, p-cdc2, and cyclin B1, to induce G2/M cell cycle arrest. Furthermore, HMH inhibited the PI3K/AKT/mTOR pathway by significantly reducing p-AKT expression in combination with LY294002, an AKT inhibitor. These results indicate that mitogen-activated protein kinases (MAPKs) and AKT/FOXO3a signaling pathways mediate the induction of cell cycle arrest following HMH treatment. Therefore, HMH could be a potential active compound for anticancer bioactivity in BC cells.

Harmine-inspired design and synthesis of benzo[d]imidazo[2,1-b]thiazole derivatives bearing 1,3,4-oxadiazole moiety as potential tumor suppressors.

Standard chemotherapy and personalized target therapies are commonly used in patients with advanced non-small cell lung cancer (NSCLC). However, multidrug resistance (MDR) and tumor metastasis lead to the decline of therapeutic efficacy, which are closely related to epithelial-mesenchymal transition (EMT). Twist1, an EMT transcription factor, plays an essential role in promoting EMT, MDR and tumor metastasis. In view of the essential role of Twist1 in the tumorigenesis of NSCLC, developing antitumor small molecules that can suppress the expression of Twist1 is of far-reaching significance for the treatment of NSCLC. A series of novel benzo[d]imidazo[2,1-b]thiazole derivatives possessing 1,3,4-oxadiazole moiety were designed based on the structure of the first-in-class Twist1 inhibitor harmine. Among the synthetic twenty-two compounds, the compound containing 2-(piperidine-1-yl) ethyl exhibited remarkable anti-proliferative activity with IC50 value of 2.03 µM and 9.80 µM against A549 and H2228 cell lines superior to harmine (IC50 = 17.12 µM against A549, IC50 = 31.06 µM against H2228). Meanwhile, western blot assay showed that the optimal compound significantly down-regulated Twist1 protein expression in a dose-dependent manner and reduced Twist1 level better than harmine. Collectively, the promising compound was identified a potential antineoplastic lead with the ability of down-regulating Twist1 level.

Cell-based assays and molecular simulation reveal that the anti-cancer harmine is a specific matrix metalloproteinase-3 (MMP-3) inhibitor.

The biological activities of harmine have been a much clearer picture in recent years, which include anti-tumor, anti-inflammation and cytotoxic properties. Numerous in vitro and in vivo animal models have confirmed its activities, but its mode of action remains a relative unsolved issue. We therefore investigated harmine for its effects on MMP-3 and the molecular interaction was also simulated. The human glioma cancer cell line, U-87 MG cells, was subjected to different concentrations (1-10 µM) of harmine for 24 h. Methylthiazol tetrazolium (MTT) test, half maximal inhibitory concentration (IC50), western blot analysis, enzyme-linked immunosorbent assay and molecular docking through BIOVIA DiscoveryStudio™ were performed. These results showed that although harmine stimulation in vitro has very little or no effects on MMP-3 expression by U-87 MG cells, the treatment of harmine decreases MMP-3 activity in a dose dependent manner. It was further calculated that 7.9 µM is the IC50 towards MMP-3. Using a molecular dynamic simulation approach, we identified the N2, methyl of C1 and benzene ring of harmine interact with Zn2+ (2.4 Å), His205 (2.4 Å) and His211 (2.4 Å) as well as Val163 (2.7 Å) at the active site of MMP-3, respectively, and thus conferred a striking specific binding advantage. Taken altogether, the present study evidences that harmine acts as an MMP-3 inhibitor specially targeting the enzymatic active site and possibly efficiently ameliorates MMP-3-driven malignant and inflammatory diseases.

The ß-Carboline Harmine Induces Actin Dynamic Remodeling and Abrogates the Malignant Phenotype in Tumorigenic Cells.

Numerous studies have shown that alteration of actin remodeling plays a pivotal role in the regulation of morphologic and phenotypic changes leading to malignancy. In the present study, we searched for drugs that can regulate actin polymerization and reverse the malignant phenotype in cancer cells. We developed a cell-free high-throughput screening assay for the identification of compounds that induce the actin polymerization in vitro, by fluorescence anisotropy. Then, the potential of the hit compound to restore the actin cytoskeleton and reverse the malignant phenotype was checked in EWS-Fli1-transformed fibroblasts and in B16-F10 melanoma cells. A ß-carboline extracted from Peganum harmala (i.e., harmine) is identified as a stimulator of actin polymerization through a mechanism independent of actin binding and requiring intracellular factors involved in a process that regulates actin kinetics. Treatment of malignant cells with non-cytotoxic concentrations of harmine induces the recovery of a non-malignant cell morphology accompanied by reorganization of the actin cytoskeleton, rescued cell-cell adhesion, inhibition of cell motility and loss of anchorage-independent growth. In conclusion, harmine induces the reversion of the malignant phenotype by a process involving the modulation of actin dynamics and is a potential anti-tumor agent acting principally through a non-cytotoxic process.

Complexation with ß-cyclodextrin enhances apoptosis-mediated cytotoxic effect of harman in chemoresistant BRAF-mutated melanoma cells.

Harman, a natural ß-carboline alkaloid, has recently gained considerable interest due to its anticancer properties. However, its physicochemical characteristics and poor oral bioavailability have been limiting factors for its pharmaceutical development. In this paper, we described the complexation of harman (HAR) with ß-cyclodextrin (ßCD) as a promising alternative to improve its solubility and consequently its cytotoxic effect in chemoresistant melanoma cells (A2058 cell line). Inclusion complexes (ßCD-HAR) were prepared using a simple method and then characterized by FTIR, NMR and SEM techniques. Through in silico studies, the mechanism of complexation of HAR with ßCD was elucidated in detail. Both HAR and ßCD-HAR promoted cytotoxicity, apoptosis, cell cycle arrest and inhibition of cell migration in melanoma cells. Interestingly, complexation of HAR with ßCD enhanced its pro-apoptotic effect by increasing of caspase-3 activity (p < 0.05), probably due to an improvement in HAR solubility. In addition, HAR and ßCD-HAR sensitized A2058 cells to vemurafenib, dacarbazine and 5FU treatments, potentializing their cytotoxic activity. These findings suggest that complexation of HAR with natural polymers such as ßCD can be useful to improve its bioavailability and antimelanoma activity.

Synthesis of Four Optical Isomers of Antiviral Agent NK0209 and Determination of Their Configurations and Activities against a Plant Virus.

Previously, we reported for the first time that harmala alkaloids harmine and tetrahydroharmine exhibit activity against plant viruses, and we developed an analogue, designated NK0209, that efficiently prevents and controls plant virus diseases. Here, to investigate the influence of the spatial configuration of NK0209 on its antiviral activities, we synthesized its four optical isomers, determined their configurations, and evaluated their activities against tobacco mosaic virus. All four isomers were significantly more active than ningnanmycin, which is one of the most successful commercial antiviral agents, with in vivo inactivation, cure, and protection rates of 57.3 ± 1.9, 54.2 ± 3.3, and 55.0 ± 4.1% at 500 µg/mL. Furthermore, analysis of structure-activity relationships demonstrated for the first time that the spatial conformation of NK0209 is an important determinant of its antiviral activity, and our results provide information about the possible optimum configuration for interaction of this molecule with its target protein.

Harmicines - harmine and cinnamic acid hybrids as novel antiplasmodial hits.

Harmicines constitute novel hybrid compounds that combine two agents with reported antiplasmodial properties, namely ß-carboline harmine and a cinnamic acid derivative (CAD). Cu(I) catalyzed azide-alkyne cycloaddition was employed for the preparation of three classes of hybrid molecules: N-harmicines 6a-i, O-harmicines 7a-i and N,O-bis-harmicines 8a-g,i. In vitro antiplasmodial activities of harmicines against the erythrocytic stage of Plasmodium falciparum (chloroquine-sensitive Pf3D7 and chloroquine-resistant PfDd2 strains) and hepatic stage of P. berghei, as well as cytotoxicity against human liver hepatocellular carcinoma cell line (HepG2), were evaluated. Remarkably, most of the compounds exerted significant activities against both stages of the Plasmodium life cycle. The conjugation of various CADs to harmine resulted in the increased antiplasmodial activity relative to harmine. In general, O-harmicines 7 exhibited the highest activity against the erythrocytic stage of both P. falciparum strains, whereas N,O-bis harmicines 8 showed the most pronounced activity against P. berghei hepatic stages. For the latter compound, molecular dynamics simulations confirmed binding within the ATP binding site of PfHsp90, while the weaker binders, namely 6b and harmine, were found to be positioned away from this structural element. In addition, decomposition of the computed binding free energies into contributions from individual residues suggested guidelines for further derivatization of harmine towards more efficient compounds. Cytotoxicity screening revealed N-harmicines 6 as the least, and O-harmicines 7 as the most toxic compounds. Harmicines 6g, 8b and 6d exerted the most selective action towards Plasmodium over human cells, respectively. These results establish harmicines as hits for future optimisation and development of novel antiplasmodial agents.

Harmine-loaded galactosylated pluronic F68-gelucire 44/14 mixed micelles for liver targeting.

Harmine (HM), a phytoconstituent has wide range of pharmacological activities including antimicrobial, antifungal, antioxidative, and anticancer. HM has shown promising anticancer activity against liver cancer cells. However, poor aqueous solubility, multidrug pump P-gp efflux, extensive in vivo metabolism, and rapid elimination due to glucuronidation/sulfation limit clinical utility of HM. In order to overcome the drawbacks of HM, the current work reports preparation of HM-loaded galactosylated pluronic F-68 (PF68)-Gelucire® 44/14 (GL44) mixed micelles (HM-MM). 32 factorial design was used to investigate the effect of formulation variables on formation HM-loaded mixed micelles. Solvent evaporation method was used for preparation of HM-MM. The optimized HM-MM was evaluated for size, percent drug entrapped (EE), in vitro HM release, oral bioavailability, and biodistribution in rats. HM-MM with an average size 277.5 ± 3.24 nm had an EE of 86.5 ± 1.51% w/w. HM-MM released HM in a controlled manner. Additionally, HM-MM showed significant enhancement in oral bioavailability (around six-folds) of HM when compared to HM alone. Further, HM-MM showed around sevenfold higher amount of HM in the liver when compared to HM alone revealing efficient drug targeting capability. Such significant improvement in oral bioavailability of HM when formulated into mixed micelles could be attributed to solubilization of hydrophobic HM into micellar core along with P-gp inhibition effect of both galactosylated PF68 and GL44. Thus, the present work highlights galactosylated PF68 and GL44 mixed micelles as an efficient carrier system having drug targeting capability and potential to enhance bioavailability of BCS class II drugs.

Development of Kinase-Selective, Harmine-Based DYRK1A Inhibitors that Induce Pancreatic Human ß-Cell Proliferation.

DYRK1A has been implicated as an important drug target in various therapeutic areas, including neurological disorders and oncology. DYRK1A has more recently been shown to be involved in pathways regulating human ß-cell proliferation, thus making it a potential therapeutic target for both Type 1 and Type 2 diabetes. Our group, using a high-throughput phenotypic screen, identified harmine that is able to induce ß-cell proliferation both in vitro and in vivo. Since harmine has suboptimal kinase selectivity, we sought to expand structure-activity relationships for harmine's DYRK1A activity, to enhance selectivity, while retaining human ß-cell proliferation capability. We carried out the optimization of the 1-position of harmine and synthesized 15 harmine analogues. Six compounds showed excellent DYRK1A inhibition with IC50 in the range of 49.5-264 nM. Two compounds, 2-2 and 2-8, exhibited excellent human ß-cell proliferation at doses of 3-30 µM, and compound 2-2 showed improved kinase selectivity as compared to harmine.

Suppression of Non-Small Cell Lung Cancer Growth and Metastasis by a Novel Small Molecular Activator of RECK.

BACKGROUND/AIMS: Reversion-inducing cysteine-rich protein with kazal motifs (RECK) is a novel tumor suppressor gene that is critical for regulating tumor cell invasion and metastasis. The expression of RECK is dramatically down-regulated in human cancers. Harmine, a tricyclic compound from Peganum harmala, has been shown to have potential anti-cancer activity. METHODS: Cell proliferation assay (CCK-8 cell viability assay), cell cycle analysis (detection by flow cytometry), apoptosis staining assay (TUNEL staining), cell migration assay and invasion assay (transwell assay) were carried out to investigate the Harmine's efficacy on non-small cell lung cancer (NSCLC) cells in vitro. A549-luciferase cell orthotropic transplantation xenograft mouse model was used to determine the effect of Harmine treatment on NSCLC in vivo. Western blotting analysis of cell growth and metastasis related signal pathways was conducted to investigate the molecular mechanism of Harmine's inhibitory effect on NSCLC. RESULTS: Harmine treatment effectively inhibited cell proliferation and induced the G1/S cell cycle arrest of NSCLC cells. Further study proved that Harmine treatment led to apoptosis induction. Furthermore, treatment with NSCLC cells with Hamine resulted in decreased cell migration and cell invasion in vitro. More importantly, Harmine treatment significantly suppressed the NSCLC tumor growth and metastasis in mouse xenograft model in vivo. Mechanistically, in Harmine-treated NSCLC cells, RECK expression and its downstream signaling cascade were dramatically activated. As a consequence, the expression level of MMP-9 and E-cadherin were significantly decreased. CONCLUSION: These findings identify Harmine as a promising activator of RECK signaling for metastatic NSCLC treatment.

Harmines inhibit cancer cell growth through coordinated activation of apoptosis and inhibition of autophagy.

Harmine and its analogs have long been considered as anticancer agents. In vitro analyses suggested that intercalating DNA or inhibiting topoisomerase might contribute to the cytotoxic effect of this class of compound. However, this idea has not been rigorously tested in intact cells. By synthesizing novel derivatives, here we demonstrate that harmines did not activate the DNA damage response, a cellular signaling commonly induced by agents that intercalate DNA or inhibit topoisomerase. These findings suggest that mechanisms other than DNA intercalating or topoisomerase inhibiting contribute to the toxicity of harmines in vivo. Using a novel N2-benzyl and N9-arylated alkyl compound 10f that has good solubility and stability as the model, we show that harmines strongly inhibited the growth of cancer cells originated from breast, lung, bone and pancreas, but not that of normal fibroblasts. We further show that 10f induced apoptosis and inhibited autophagy in a dose and time-dependent manner. An apoptosis inhibitor suppressed 10f-induced cell death. Together, our results reveal previously unidentified insights into the anticancer mechanism of harmines, supporting future development of this compound class in the treatment of human cancers.

Combination of doxorubicin with harmine-loaded liposomes exerting synergistic antitumor efficacy.

CONTEXT: Long-circulation (PEGLip), pH-sensitive (PEOzLip), and active targeted liposomes (PEG-TATLip)-loading doxorubicin (DOX) and harmine (HM) were prepared. Their physicochemical properties and antitumor effect were investigated. OBJECTIVES: The aims of the present study were to evaluate synergistic antitumor efficacy. MATERIALS AND METHODS: Liposomes were prepared by using thin-film dispersion, active drug-loading and target post-insertion method. Subsequently physiochemical properties including particle size distribution, zeta potential, entrapment efficiency (EE), drug-loading content and in-vitro release were determined. Besides, the in vitro cytotoxicity of free drugs and drug-loaded liposomes was explored by using a Sulforhodamine-B Staining assay and the combination index values (CI Value) were calculated. Finally, the cellular uptake experiments by MCF-7cells were carried out via flow cytometry. RESULTS AND DISCUSSION: All liposomes enhanced the antitumor effect significantly compared to free drugs. Among liposomes, PEG-TATLip enhanced the antitumor effect significantly compared to others. DOX and HM had moderate synergism with CI Value 0.85 for free drugs, 0.81 for PEGLip, 0.72 for PEOzLip, and 0.84 for PEG-TATLip respectively when the weight ratio of two drugs was 1:2. Moreover, the similarity between DOX and HM such as physicochemical properties, in vitro release modes and in vitro uptake kinetics characteristics when they were in the same formulations proved it possible for them to be delivered together. CONCLUSION: Active targeting liposomes were the most effective delivery system as compared with pH-sensitive and long circulation liposomes. Additionally, DOX and HM could be co-delivered in liposomes and they could play moderate synergism effect in antitumor efficacy.

Shipment of a photodynamic therapy agent into model membrane and its controlled release: A photophysical approach.

Harmine, an efficient cancer cell photosensitizer (PS), emits intense violet color when it is incorporated in well established self assembly based drug carrier formed by cationic surfactants of identical positive charge of head group but varying chain length, namely, dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB) and cetyltrimethylammonium bromide (CTAB). Micelle entrapped drug emits in the UV region when it interacts with non-toxic ß-cyclodextrin (ß-CD). Inspired by these unique fluorescence/structural switching properties of the anticancer drug, in the present work we have monitored the interplay of the drug between micelles and non-toxic ß-CDs. We have observed that the model membranes formed by micelles differing in their hydrophobic chain length interact with the drug differently. Variation in the surfactant chain length plays an important role for structural switching i.e. in choosing a particular structural form of the drug that will be finally presented to their targets. The present study shows that in case of necessity, the bound drug molecule can be removed from its binding site in a controlled manner by the use of non-toxic ß-CD and it is exploited to serve a significant purpose for the removal of excess/unused adsorbed drugs from the model cell membranes. We believe this kind of ß-CD driven translocation of drugs monitored by fluorescence switching may find possible applications in controlled release of the drug inside cells.

Differential Perturbation of the Protrotropic Equilibrium of a Biological Photosensitizer within Bile Salt Aggregates of Varying Hydrophobicity: A Fluorimetric Investigation.

The present work reveals the binding interactions of a credible cancer cell photosensitizer, harmane (HM), with some selected bile salt aggregates of dissimilar hydrophobicity viz. sodium deoxycholate (NaDC), sodium cholate (NaC) and sodium taurocholate (NaTC). The explicit variation of the prototropic equilibrium of the photosensitizer both in the ground and excited state has been utilized to scrutinize the interaction phenomena. Differential modulation in the prototropic equilibrium of HM in the aforesaid aggregates has been explained on the basis of the structural dissimilarities of the bile salt monomers. The contrived hydrophobic surroundings provided by the aggregates have been reflected on the spectroscopic results, especially in the time-resolved fluorescence and the rotational dynamical behavior of the molecule of interest. Slow solvent reorientation time with regard to the lifetime of HM proliferated by the red-edge effect in two specific bile salts namely NaC and NaTC, whereas its absence in NaDC aggregates has also been elucidated on the basis of accessibility of the solvent molecules within the aggregates.

Binding of Harmine Derivatives to DNA: A Spectroscopic Investigation.

Harmine belongs to a group of ß-carboline alkaloids endowed with antitumor properties. Harmine and its derivatives are thought to bind to DNA and interfere with topoisomerase activities. We investigated the base-dependent binding of harmine, and three of its synthetic anticancer-active derivatives to the genomic DNA from calf thymus and two synthetic 20-mer double helices, the poly(dG-dC)·poly(dG-dC) and the poly(dA-dT)·poly(dA-dT), by means of UV-Vis and circular dichroism (CD) spectroscopies. The data show that the DNA binding and stabilising properties of the investigated derivatives are base pair-dependent. These results could be used as a guide to design and develop further bioactive analogues.