Human Cervical Adenocarcinoma HeLa Cells Research Articles

Effect of sun ginseng potentiation on epirubicin and paclitaxel-induced apoptosis in human cervical cancer cells

BackgroundSun ginseng (SG), a specific formulation of quality-controlled red ginseng, contains approximately equal amounts of three major ginsenosides (RK1, Rg3, and Rg5), which reportedly has antitumor-promoting activities in animal models. MethodsMTT assay was used to assess whether SG can potentiate the anticancer activity of epirubicin or paclitaxel in human cervical adenocarcinoma HeLa cells, human colon cancer SW111C cells, and SW480 cells; apoptosis status was analyzed by annexin V-FITC and PI and analyzed by flow cytometry; and apoptosis pathway was studied by analysis of caspase-3, -8, and -9 activation, mitochondrial accumulation of Bax and Bak, and cytochrome c release. ResultsSG remarkably enhances cancer cell death induced by epirubicin or paclitaxel in human cervical adenocarcinoma HeLa cells, human colon cancer SW111C cells, and SW480 cells. Results of the mechanism study highlighted the cooperation between SG and epirubicin or paclitaxel in activating caspase-3 and -9 but not caspase-8. Moreover, SG significantly increased the mitochondrial accumulation of both Bax and Bak triggered by epirubicin or paclitaxel as well as the subsequent release of cytochrome c in the targeted cells. ConclusionSG significantly potentiated the anticancer activities of epirubicin and paclitaxel in a synergistic manner. These effects were associated with the increased mitochondrial accumulation of both Bax and Bak that led to an enhanced cytochrome c release, caspase-9/-3 activation, and apoptosis. Treating cancer cells by combining epirubicin and paclitaxel with SG may prove to be a novel strategy for enhancing the efficacy of the two drug types.

PEGylated graphene oxide as a nanocarrier for podophyllotoxin

Graphene, a two-dimensional nanomaterial, has become a hot spot of research at the interface of nanotechnology and biomedicine. In this study, the oxidized form of graphene, graphene oxide (GO), was functionalized with 6-armed polyethylene glycol (PEG), which rendered it stable and biocompatible in physiological solution. The successful synthesis of PEGylated graphene oxide (GO-PEG) nanocarrier with low toxicity was confirmed by UV–Vis spectroscopy, Fourier-transform infrared spectroscopy, atomic force microscopy, and thermogravimetric analysis. By dynamic light scattering (DLS), the size distribution of the nanoparticles were shown to be 60–200 nm. Furthermore, a complex by loading an aromatic anticancer compound, podophyllotoxin (PPT), onto GO-PEG (GO-PEG/PPT) via π–π stacking and hydrophobic interactions was investigated. It was demonstrated that GO-PEG/PPT showed remarkably high cytotoxicity compared to free PPT in both the human cervical adenocarcinoma HeLa cell line and human hepatoma SMMC-7721 cell line. The loading and delivery of anticancer drugs using this kind of graphene-based nanocarrier may find potential application in biomedicine.

Antimony(III) halide compounds of thioureas: Structures and biological activity

Antimony(III) halide compounds (SbX3, X=Cl and Br) of thioureas; tetramethylthiourea (TMTU), N,N′-diethylthiourea (DETU) and 1,3-diisopropyl-2-thiourea (DIPTU) of formulae {[SbCl3(TMTU)]n} (1), {[SbBr3(TMTU)]n} (2), {[mer-SbCl3(DIPTU)3] [fac-SbCl3(DIPTU)3] C6H6} (3) and {[SbBr2(DETU)2]+·Br−}n (4) were synthesized. The complexes were characterized by their melting point, elemental analysis, FT-IR spectroscopy, FT-Raman spectroscopy, 1H and 13C NMR spectroscopy and Thermal Gravimetry-Differential Thermal Analysis (TG-DTA). The crystal and molecular structures of complexes 2–4 were determined with single crystal X-ray diffraction analysis. Compounds 1 and 2 are polymers with pseudotrigonal–bipyramidal (ψ-TBP) geometry in each monomeric unit. Compound 3 is a monomer with octahedral (Oh) geometry around Sb(III). Two different coordination modes of the ligands around antimony ions are observed in 3 forming two units. One with meridional orientation and the other with facial one. This complex is the first example of polymeric antimony(III) where two sequential antimony atoms have two different coordination modes. Two sulfur atoms and two bromines form a pseudotrigonal–bipyramidal cationic [SbBr2(L)2]+ part with a bromide as counter anion in complex 4. Complexes 1–4 and their ligands were evaluated for their in vitro cytotoxic activity against human breast adenocarcinoma (MCF-7) and human cervical adenocarcinoma (HeLa) cells. Principal components analysis (PCA) was performed to discriminate the significant physicochemical molecular descriptors while regression analysis successfully relates the experimental inhibitory concentrations, (IC50) to the independent variables indexed by PCA.

Crinane Alkaloids of the Amaryllidaceae with Cytotoxic Effects in Human Cervical Adenocarcinoma (HeLa) Cells

The family Amaryllidaceae has a long history of usage in the traditional medicinal practices of the indigenous peoples of South Africa, with three of its species known to be used for cancer treatment. Furthermore, the Amaryllidaceae is widely recognized for its unique alkaloid constituents, several of which exhibit potent and selective cytotoxic activities. In this study, several crinane alkaloids derived from local Amaryllidaceae species were examined for cytotoxic effects against the human cervical adenocarcinoma cell line, of which distichamine was the most potent (IC50 2.2 microM).

Synthesis of novel pyrazolo[3,4-d]pyrimidinone derivatives as cytotoxic inhibitors

Various α-fonctionalized iminoethers 2 were easily prepared from ethyl 5-amino-3-substituted-1-phenyl-1H-pyrazole-4-carboxylate 1. The reaction of iminoethers 2 with ammonia afforded 3-substitued-1-phenyl-1H-pyrazolo[3,4-d] pyrimidin-4(5H)-ones 3 which were also synthesized by the addition of formamide to ethyl 5-amino-3-substituted-1-phenyl-1H-pyrazole-4-carboxylate 1. The 5-amino-3-substitued-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-ones 4 were obtained from hydrazonolysis of iminoethers 2. Otherwise, the condensation of these intermediates 2 with a series of some primary amines and hydroxylamine led respectively, to the corresponding 3,5-disubstitued-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-ones 5 and the 3-substitued-5-hydroxy-1-phenyl-1H-pyrazolo[3,4-d] pyrimidin-4-(5H)-ones 6. The synthesized compounds 1-6 were completely characterized by 1H NMR, 13C NMR, IR and HRMS. Some synthesized compounds were evaluated for their cytotoxic effect using the Human cervical adenocarcinoma Hela cell line.

Synthesis, structural characterization and cytostatic properties of N,N-dicyclohexyldithiooxamide complexes of antimony(III) halides (SbX3, X: Br or I)

The novel antimony(III) halide complexes with the bi-dentate substituted dithiooxamide ligand, N,N-dicyclohexyldithiooxamide (HDTOA) of formulae {[SbBr3(HDTOA)1.5]}n (1) and {[SbI3(HDTOA)1.5].C6H6}n (2), were prepared by reacting antimony(III) bromide or antimony(III) iodide with HDTOA in 1:1 molar ratio. The compounds were characterized by their m.p., FT-IR spectroscopy, Raman spectroscopy, 1H, 13C NMR spectroscopy, Thermal Gravimetric – Differential Thermal Analysis (TG-DTA) and single crystal X-ray diffraction analysis. Both complexes are polymeric consisting by [SbX3(HDTOA)1.5] building blocks. The octahedral geometric demand of the metal center is covered by three halides and three sulfur atoms from three different HDTOA ligands with facial conformation in both complexes. Each ligand bridged two metal centers of two units, through sulfur donor atoms, acting as bi-dentate bridging ligand. Complexes 1 and 2 were also tested for in vitro cytotoxic activity against human breast adenocarcinoma (MCF-7) and human cervical adenocarcinoma (HeLa) cells. Principal components analysis (PCA) was performed to discriminate the significant physicochemical molecular descriptors while regression analysis successfully related the experimental inhibitory concentrations, (IC50) to the independent variables indexed by PCA. The calculated IC50 values are satisfactorily compared with the measured inhibitory activity of the complexes.

Alkaloids from Boophone haemanthoides (Amaryllidaceae)

In this study, the South African Amaryllid Boophone haemanthoides was examined for its phytochemical composition and cytotoxicity. In the process eight alkaloid structures, including the new compound distichaminol, were identified in bulb ethanolic extracts. Of the isolates, lycorine and distichamine exhibited strong activities against human acute lymphoblastic leukemia (CEM), breast adenocarcinoma (MCF7) and cervical adenocarcinoma (HeLa) cells with IC50S ranging from 1.8 to 9.2 microM.

Inhibition of Signal Transducer and Activator of Transcription 3 and Cyclooxygenase-2 Is Involved in Radiosensitization of Cepharanthine in HeLa Cells

To investigate the radiosensitizing effects of cepharanthine (CEP) in the human cervical adenocarcinoma HeLa cell line and to examine the underlying mechanisms. Survival of HeLa cells after treatment with or without ionizing radiation (IR) and CEP administration was investigated. MTT assays and apoptosis analysis were used to assess cytotoxicity. Nude mouse xenografts were established to evaluate the antitumor effects of CEP and IR in vivo. Expression of signal transducer and activator of transcription 3 (STAT3) and its downstream signaling molecules as well as cyclooxygenase-2 (COX-2) were examined by Western blot analysis. Clonogenic assays showed that treatment with CEP and IR resulted in significant radiosensitization. Cepharanthine and IR treatment achieved maximum cytotoxic effects on HeLa cells with regard to apoptosis induction. Cepharanthine efficiently decreased IR-induced STAT3 and COX-2 activation. The STAT3 target genes, including the antiapoptotic Bcl-2 and the cell cycle regulator c-Myc, were decreased concomitantly. In vivo administration of CEP (20 mg/kg every 2 days) combined with radiation in HeLa xenografts enhanced tumor growth delay and apoptosis (indicated by activated caspase-3 Western blot analysis), with reduced expression of STAT3, Bcl-2, c-Myc, and COX-2. Cepharanthine was shown to induce radiation sensitization in HeLa cells in vitro and in vivo. The inhibitory effects of CEP on STAT3 signaling pathway and COX-2 help us to better understand the radiosensitization of CEP.

Resistance of cervical adenocarcinoma cells (HeLa) to venom from the scorpion Centruroides limpidus limpidus.

BackgroundThe venom of Centruroides limpidus limpidus (Cll) is a mixture of pharmacologically active principles. The most important of these are toxic proteins that interact both selectively and specifically with different cellular targets such as ion channels. Recently, anticancer properties of the venom from other scorpion species have been described. Studies in vitro have shown that scorpion venom induces cell death, inhibits proliferation and triggers the apoptotic pathway in different cancer cell lines. Herein, after treating human cervical adenocarcinoma (HeLa) cells with Cll crude venom, their cytotoxic activity and apoptosis induction were assessed.ResultsCll crude venom induced cell death in normal macrophages in a dose-dependent manner. However, through viability assays, HeLa cells showed high survival rates after exposure to Cll venom. Also, Cll venom did not induce apoptosis after performing ethidium bromide/acridine orange assays, nor was there any evidence of chromatin condensation or DNA fragmentation.ConclusionsCrude Cll venom exposure was not detrimental to HeLa cell cultures. This may be partially attributable to the absence of specific HeLa cell membrane targets for molecules present in the venom of Centruroides limpidus limpidus. Although these results might discourage additional studies exploring the potential of Cll venom to treat human papilloma cervical cancer, further research is required to explore positive effects of crude Cll venom on other cancer cell lines.

Oxidative stress-mediated cytotoxicity and apoptosis induction by TiO2 nanofibers in HeLa cells

Titanium dioxide nanoparticles are increasingly being used in pharmaceutical and cosmetic products. The high aspect ratio of fibrous nanomaterials, such as carbon nanotubes and TiO2 nanofibers (TiO2NFs), similar to the one used in this study makes them an attractive structural material and has attracted a lot of attention due to their possible negative health effects as suggested by their morphological similarities with asbestos. In the present study, therefore, toxicity of TiO2NFs was evaluated in human cervical adenocarcinoma HeLa cells. The TEM and XRD analyses showed that TiO2NFs used in this study are pure with uniform diameter of around 200nm, and their length to width aspect ratio ranged between 5 and 15. Exposure of HeLa cells to TiO2NFs induced significant cytotoxicity even at doses as low as 2μg/ml. The intracellular uptake of TiO2NFs in cells was shown by Alizarin Red S (ARS) labeled nanofibers. The mechanism of toxicity is mainly due to the induction of cellular oxidative stress, as revealed by elevated ROS levels, reduced antioxidant levels, and increased lipid peroxidation leading to apoptosis. The cell cycle analysis indicated G2/M cell cycle arrest in the cells exposed to TiO2NF. TiO2NFs treatment to HeLa cells resulted in increased expression of proapoptotic proteins Bax with an increase in cytosolic Cytochrome-C and inhibition of anti-apoptotic protein Bcl-2. Our results revealed the potential mechanism of cellular effects of TiO2NFs.

Nanobarcoding: detecting nanoparticles in biological samples using in situ polymerase chain reaction.

BackgroundDetermination of the fate of nanoparticles (NPs) in a biological system, or NP biodistribution, is critical in evaluating an NP formulation for nanomedicine. Current methods to determine NP biodistribution are greatly inadequate, due to their limited detection thresholds. Herein, proof of concept of a novel method for improved NP detection based on in situ polymerase chain reaction (ISPCR), coined “nanobarcoding,” is demonstrated.MethodsNanobarcoded superparamagnetic iron oxide nanoparticles (NB-SPIONs) were characterized by dynamic light scattering, zeta potential, and hyperspectral imaging measurements. Cellular uptake of Cy5-labeled NB-SPIONs (Cy5-NB-SPIONs) was imaged by confocal microscopy. The feasibility of the nanobarcoding method was first validated by solution-phase PCR and “pseudo”-ISPCR before implementation in the model in vitro system of HeLa human cervical adenocarcinoma cells, a cell line commonly used for ISPCR-mediated detection of human papilloma virus (HPV).ResultsDynamic light-scattering measurements showed that NB conjugation stabilized SPION size in different dispersion media compared to that of its precursor, carboxylated SPIONs (COOH-SPIONs), while the zeta potential became more positive after NB conjugation. Hyperspectral imaging confirmed NB conjugation and showed that the NB completely covered the SPION surface. Solution-phase PCR and pseudo-ISPCR showed that the expected amplicons were exclusively generated from the NB-SPIONs in a dose-dependent manner. Although confocal microscopy revealed minimal cellular uptake of Cy5-NB-SPIONs at 50 nM over 24 hours in individual cells, ISPCR detected definitive NB-SPION signals inside HeLa cells over large sample areas.ConclusionProof of concept of the nanobarcoding method has been demonstrated in in vitro systems, but the technique needs further development before its widespread use as a standardized assay.

Optical parameters measurement for diagnostic and photodynamic therapy of human cervical adenocarcinoma (HeLa) cell line

The purpose of this study was to investigate the optical properties, absorption coefficient (μ a ) scattering coefficient (μ s ) and refractive indices, (n) of HeLa cell line in a suspension of 2% minimum essential medium (MEM) at two different (632.8 and 532.0 nm) wave lengths of laser light. Optical properties were determined with Kubelka Munk Model (KMM) and refractive index measurement was made through minimum angle of deviation method (MAD). We reported μ a = 8.643 ± 0.187 and 2.348 ± 0.249 cm−1 and μ s = 5.609 ± 0.287 and 88.166 ± 2.833 cm−1 at 632.8 and 532.0 nm, respectively. Refractive index was found to be 1.332 and 1.312 at 632.8 nm and 532.0 nm, respectively. The discussed results provide a route of information for clinical diagnosis, therapeutic application and dosimetry studies in HeLa and other cell lines.

Latex of Euphorbia Antiquorum Induces Apoptosis in Human Cervical Cancer Cells via c-Jun N-terminal Kinase Activation and Reactive Oxygen Species Production

Latex of Euphorbia antiquorum (EA) has inhibitory effects on several different cancer cell lines. However, the molecular mechanism of EA inhibitory effects on human cervical cancer HeLa cell growth has not been explored. EA induced apoptosis, which was characterized by morphological change, DNA fragmentation, increased sub-G1 population, and alterations in levels of apoptosis-associated proteins. Treatment with EA increased cell death and expression levels of caspase-8, -9, and -3. EA suppressed expression of Bcl-2, increased Bax, and reduced cleavage of Bid and the translocation of tBid to the mitochondria and the release of cytochrome c from mitochondria. EA caused a loss of mitochondrial membrane potential (ΔΨm) and an increase in cellular reactive oxygen species (ROS). EA-induced ROS formation was suppressed by cyclosporine A (an inhibitor of the ΔΨm) or allopurinol (an effective scavenger of ROS). EA also increased expression of Fas, FasL, and c-Jun N-terminal kinase (JNK), p38, and mitogen-activated protein kinase (MAPK) and decreased expression of extracellular signal-regulated kinase (ERK) 1/2-p. Co-treatment with the JNK inhibitor SP600125 inhibited EA-induced apoptosis and the activation of caspase-8, -9, and -3. Results of this study provide support for the hypothesis that EA causes cell death via apoptotic pathways in human cervical adenocarcinoma HeLa cells.

Major determinants of photoinduced cell death: Subcellular localization versus photosensitization efficiency

We present a study on whether and to what extent subcellular localization may compete favorably with photosensitization efficiency with respect to the overall efficiency of photoinduced cell death. We have compared the efficiency with which two cationic photosensitizers, namely methylene blue (MB) and crystal violet (CV), induce the photoinduced death of human cervical adenocarcinoma (HeLa) cells. Whereas MB is well known to generate singlet oxygen and related triplet excited species with high quantum yields in a variety of biological and chemical environments (i.e., acting as a typical type II photosensitizer), the highly mitochondria-specific CV produces triplet species and singlet oxygen with low yields, acting mostly via the classical type I mechanism (e.g., via free radicals). The findings described here indicate that the presumably more phototoxic type II photosensitizer (MB) does not lead to higher degrees of cell death compared to the type I (CV) photosensitizer. In fact, CV kills cells with the same efficiency as MB, generating at least 10 times fewer photoinduced reactive species. Therefore, subcellular localization is indeed more important than photochemical reactivity in terms of overall cell killing, with mitochondrial localization representing a highly desirable property for the development of more specific/efficient photosensitizers for photodynamic therapy applications.

Cytotoxic Activity of Paris quadrifolia Extract and Isolated Saponin Fractions Against Human Tumor Cell Lines

Steroidal saponins isolated from many plant species belonging to Monocotyledones display potent cytotoxic activity towards many human tumor cells. We examined the cytotoxic effects of crude Paris quadrifolia extract for the first time, testing isolated saponin-rich fractions against four different human cell lines using the [(3-(4,5dimethylthiazol-2-yl)]-2,5-diphenyltetrazolium bromide (MTT) assay. Cytotoxic activity was tested against human promyelocytic leukemia (HL-60) cells, human cervical adenocarcinoma (HeLa) cells and human breast cancer (MDA-MB-468) cells. Human skin fibroblasts were used as non-neoplastic control cells. Our results show significant activity of the weakly water-soluble solid residue and butanolic fraction against HL-60 and HeLa cells. The solid residue exerted cytotoxicity against all tested cell lines.

Eupafolin, a flavonoid isolated from Artemisia princeps, induced apoptosis in human cervical adenocarcinoma HeLa cells

Although eupafolin, a flavone found in Artemisia princeps Pampanini, has been shown to inhibit the growth of several human cancer cells, its mode of action is poorly understood. In this study, we investigated the pro-apoptotic activities of eupafolin in human cervical carcinoma HeLa cells. It was found that eupafolin induced apoptosis in a dose-dependent manner, as evidenced by DNA fragmentation and the accumulation of positive cells for annexin V. In addition, eupafolin triggered the activations of caspases-3, -6, -7, -8, and -9 and the cleavages of their substrates, such as, poly (ADP-ribose) polymerase and lamin A/C. Furthermore, treatment with eupafolin resulted in a loss of mitochondrial membrane potential (DeltaPsi(m)), increased the release of cytochrome c to the cytosol, and altered the expression levels of B-cell lymphoma 2 (Bcl-2) family proteins. Interestingly, caspase-8, an initiator caspase, was activated after the loss of DeltaPsi(m) and the activations of caspases-3 and -9. Moreover, treatment with z-DEVD-fmk (a specific caspase-3 inhibitor) and the overexpression of Bcl-2 prevented eupafolin-stimulated caspase-8 activation. Altogether, these results suggest that the eupafolin-induced apoptosis in HeLa cells is mediated by caspase-dependent pathways, involving caspases-3, -9, and -8, which are initiated by the Bcl-2-dependent loss of DeltaPsi(m).

Antioxidant, cytotoxic and apoptotic activity of Drosophyllum lusitanicum extracts.

This study was designed to determine the antioxidant, anti-proliferative, cytotoxic and apoptogenic properties of aqueous, methanol and hexane extracts fromDrosophyllum lusitanicum leaves. Assays showed that the methanol extract had the highest antioxidant activity (F-C: 1188.06 ± 52.96 µmolGAE/mgextract; TEAC: 432.23 ± 6.71 µmolTE/mgextract; ORAC: 764.18 ± 61.18 µmolTE/mgextract) and the hexane extract had the lowest (F-C: 20.16 ± 1.62 µmolGAE/mgextract; TEAC: 20.94 ± 1.73 µmolTE/mgextract; ORAC: 50.66 ± 0.91 µmolTE/mgextract). The effect of plant extracts on HeLa cells proliferation and viability was evaluated by the crystal violet and WST-1 assays, respectively and apoptotic cells were determined using PI staining of DNA fragmentation by flow cytometry (sub-G1 peak). It was observed that the methanol extract inhibited cell proliferation and induced apoptosis on human cervical adenocarcinoma HeLa cells. Moreover, results indicated that the D. lusitanicum hexane extract exhibited cytotoxic effects on HeLa cells via apoptosis and also arrested cell cycle progression in G2/M phase. As damaging events are frequently correlated with oxidative stress, the prevalence of both antioxidant and anti-proliferative properties in the same plant species could be beneficial in terms of rational, preventive or therapeutic purposes. Thus D. lusitanicum may be a potential candidate in the field of anticancer drug discovery. Key words: Anti-proliferation, apoptosis, cell cycle, HeLa cells, carnivorous plant, viability.

Knockdown of BMI-1 causes cell-cycle arrest and derepresses p16INK4a, HOXA9 and HOXC13 mRNA expression in HeLa cells

The human oncogene B-cell-specific Moloney murine leukemia virus integration site 1 (BMI-1) is a member of the mammalian Polycomb group family. The overexpression of BMI-1 is associated with human malignancies. In this study, the effects of knockdown of BMI-1 by shRNA-mediated RNA interference on cell cycle and possible downstream targets in human cervical adenocarcinoma HeLa cells were investigated. As a result, when the shRNA plasmid was stably introduced into the cell line, the mRNA and protein of BMI-1 were specifically down-regulated, and the cells increased in the phase of G1 and cells in S phase significantly decreased by flow cytometric analysis; the knockdown of BMI-1 expression could lead to significant up-regulation of p16INK4a, HOXA9 and HOXC13 mRNA expression, but hTERT and HOXB4 mRNA expression did not change significantly. In conclusion, RNAi-mediated knockdown of BMI-1 expression can induce cell-cycle arrest and up-regulate p16INK4a, HOXA9 and HOXC13 in HeLa cells. Our results suggest that targeting BMI-1 might be a therapeutic potential for the treatment of cancer.

In vitro cytotoxic and antiproliferative activities of marine macroalgae from Yucatán, Mexico

Extracts from 27 marine algal species (14 Rhodophyta, 5 Phaeophyta, and 8 Chlorophyta) from the Yucatán Peninsula (Mexico) were evaluated for cytotoxic and antiproliferative activity by 3(4,5-dimethylthiazole-2-yl)-2,5 diphenyltetrazolium bromide (MTT) and sulforhodamine B (SRB) assays, respectively. To determine the specificity of cytotoxic activity against tumor cells, the selective index (SI) was also calculated. The following cancer cell lines were employed: normal canine kidney (MDCK) cells, human laryngeal carcinoma (Hep-2) cells, human cervical adenocarcinoma (HeLa) cells, and human nasopharyngeal carcinoma (KB) cells. The results indicated that 44% and 51% of the algal species tested showed cytotoxic and antiproliferative activity, respectively. Most of the cytotoxic extracts were from species of Chlorophyta, with Udotea flabellum and U. conglutinate showing the highest cytotoxic activity against all the cancer cell lines. For Rhodophyta, the Bryothamnion triquetrum extract showed outstanding selective cytotoxicity against Hep-2 cells (CC50 8.29 µg mL–1, SI = 12.04). Two of the five species of Phaeophyta tested (Lobophora variegata and Dictyota caribaea) showed high cytotoxicity activity against the KB cell line. The data show that these species are a potential source of compounds for the treatment of certain cancer diseases.

Characterization of the Group II Chaperonin TriC derived from Human Cervical Adenocarcinoma (HeLa) Cells

Molecular chaperones are key elements in protein folding pathways, and there are numerous proteins which are unable to fold in the absence of one or more molecular chaperones. Eukaryotic chaperones can be broadly separated into two families: chaperones, which sequester and protect unfolded proteins, but do not facilitate folding, and chaperonins, which require ATP, and actively fold nacent or misfolded proteins. The mammalian chaperonin TRiC, in addition to being required for actin and tubulin folding, binds and refold several disease causing proteins in vitro, including those associated with Alzheimer's disease, Von Hippel Landau tumor, and Huntington's disease. This refolding activity has revealed TRiC as a possible therapeutic agent for the treatment and prevention of aggregation diseases. We have purified TriC from cervical adenocarcinoma cells. To assess the properties of Human TriC, we are characterizing its interactions of with human γ Crystallins. Crystallins are a family of structural proteins found in the lens of the human eye, and aggregation of these proteins is thought to be the cause of cataract. Methanococcus marapaludis chaperonin Mm-Cpn, a homolog of human TriC, has been shown to both suppress aggregation of Human γ Crystallins, and refold the Crystallins to a native-like conformation. Suppression of γ Crystallin aggregation is being investigated using UV/Vis spectroscopy, and the ability of TriC to restore unfolded γ Crystallin to a native fold investigated using size exclusion chromatography. In collaboration with fellow members of the Center for Protein Folding Machinery, we are investigating the possibility of visualizing the crystallin substrate in the chaperonin/substrate complex by Cryo-EM.Supported by an NIH Roadmap Award to the Center for Protein Folding Machinery (http://ncmi.bcm.tmc.edu/nanomedicine).