Cervical Carcinoma Cell Line HeLa Research Articles

Inhibitory Effects of the Active Components Isolated from Satureja Boissieri Hausskn. Ex Boiss. On Human Cervical Cancer Cell Line

The aim of this study was to isolate the active components from the essential oil (EO) of Satureja boissieri and to investigate the cytotoxic effects of these components on human cervical epithelioid carcinoma (HeLa) cell line. The major components of EO were found to be p-cymene (23.15%), γ-terpinene (22.84%), thymol (18.96%) and carvacrol (21.25%) using GC-MS. The components were separated by column chromatography and p-cymene, thymol and spathulenol were isolated as pure terpenoids. The cytotoxic activity of the components was investigated using the xCELLigence system (Real Time Cell Analyzer). The pure compounds, p-cymene and thymol exhibited excellent cytotoxic effects against HeLa cell line. Practical Applications Satureja boissieri Hausskn. ex Boiss.(Lamiaceae) is known as Catri/Kekik and used as a condiment and herbal tea in the kitchen of local people in Turkey. The genus Satureja has therapeutic properties because of its high amounts of active components such as thymol, carvacrol, p-cymene and γ-terpinene. The results demonstrated that S. boissieri and its active components may be suggested as a promising natural agents for alleviating human cervical epithelioid carcinoma cell growth.

Cationic niosomes an effective gene carrier composed of novel spermine-derivative cationic lipids: effect of central core structures

Context: Cationic niosomes formulated from Span 20, cholesterol (Chol) and novel spermine-based cationic lipids of multiple central core structures (di(oxyethyl)amino, di(oxyethyl)amino carboxy, 3-amino-1,2-dioxypropyl and 2-amino-1,3-dioxypropyl) were successfully prepared for improving transfection efficiency in vitro. The niosomes composed of spermine cationic lipid with central core structure of di(oxyethyl)amino revealed the highest gene transfection efficiency.Objectives: To investigate the factors affecting gene transfection and cell viability including differences in the central core structures of cationic lipids, the composition of vesicles, molar ratio of cationic lipids in formulations and the weight ratio of niosomes to DNA.Methods: Cationic niosomes composed of nonionic surfactants (Span20), cholesterol and spermine-based cationic lipids of multiple central core structures were formulated. Gene transfection and cell viability were evaluated on a human cervical carcinoma cell line (HeLa cells) using pDNA encoding green fluorescent protein (pEGFP-C2). The morphology, size and charge were also characterized.Results and discussion: High transfection efficiency was obtained from cationic niosomes composed of Span20:Chol:cationic lipid at the molar ratio of 2.5:2.5:0.5 mM. Cationic lipids with di(oxyethyl)amino as a central core structure exhibited highest transfection efficiency. In addition, there was also no serum effect on transfection efficiency.Conclusions: These novel cationic niosomes may constitute a good alternative carrier for gene transfection.

One-pot synthesis of a photostable green fluorescent probe for biological imaging

An excited state intramolecular proton transfer fluorogen, 2-(4-(benzo[d]thiazol-2-yl)-4-hydroxyphenylcarbamoyl) benzoic acid (T4BA), has been synthesized via one-pot reaction for the first time. The cellular imaging effect of T4BA was investigated on human cervical carcinoma cell line HeLa. The fluorescence stability and cellular uptake mechanism of T4BA were also investigated. T4BA exhibits a typical fluorescent characteristic of organic small molecule and the carboxyl group of T4BA can easily form hydrogen bond with the active constituents in cytoplasm which leads to rapid (as quick as 30 s) and selective light-up of the cytoplasm of HeLa cells. Survival rate reached more than 85 % with the cultural concentration up to 100 μM, indicating almost no toxicity of T4BA to the living cells at the working concentration. Results revealed that fluorescence intensity of T4BA decreased less than 10 % after 10 min continuous laser illumination and this dye acts well over a wide pH range, indicating a significant photostability and great potential of it for commercializing as a highly attractive cell imaging agent.

Bioactive Hydantoin Alkaloids from the Red Sea Marine Sponge Hemimycale arabica.

In the course of our continuing efforts to identify bioactive secondary metabolites from Red Sea marine invertebrates, we have investigated the sponge Hemimycale arabica. The antimicrobial fraction of an organic extract of the sponge afforded two new hydantoin alkaloids, hemimycalins A and B (2 and 3), together with the previously reported compound (Z)-5-(4-hydroxybenzylidene)imidazolidine-2,4-dione (1). The structures of the compounds were determined by extensive 1D and 2D NMR (COSY, HSQC and HMBC) studies and high-resolution mass spectral determinations. Hemimycalins A (2) and B (3) represent the first examples of the natural N-alkylated hydantoins from the sponge Hemimycale arabica. Compounds 1–3 displayed variable antimicrobial activities against E. coli, S. aureus, and C. albicans. In addition, compound 1 displayed moderate antiproliferative activity against the human cervical carcinoma (HeLa) cell line. These findings provide further insight into the chemical diversity as well as the biological activity of this class of compounds.

Structure-Activity Relationship of Oligomeric Flavan-3-ols: Importance of the Upper-Unit B-ring Hydroxyl Groups in the Dimeric Structure for Strong Activities.

Proanthocyanidins, which are composed of oligomeric flavan-3-ol units, are contained in various foodstuffs (e.g., fruits, vegetables, and drinks) and are strongly biologically active compounds. We investigated which element of the proanthocyanidin structure is primarily responsible for this functionality. In this study, we elucidate the importance of the upper-unit of 4–8 condensed dimeric flavan-3-ols for antimicrobial activity against Saccharomyces cerevisiae (S. cerevisiae) and cervical epithelioid carcinoma cell line HeLa S3 proliferation inhibitory activity. To clarify the important constituent unit of proanthocyanidin, we synthesized four dimeric compounds, (−)-epigallocatechin-[4,8]-(+)-catechin, (−)-epigallocatechin-[4,8]-(−)-epigallocatechin, (−)-epigallocatechin-[4,8]-(−)-epigallocatechin-3-O-gallate, and (+)-catechin-[4,8]-(−)-epigallocatechin and performed structure–activity relationship (SAR) studies. In addition to antimicrobial activity against S. cerevisiae and proliferation inhibitory activity on HeLa S3 cells, the correlation of 2,2-diphenyl-l-picrylhydrazyl radical scavenging activity with the number of phenolic hydroxyl groups was low. On the basis of the results of our SAR studies, we concluded that B-ring hydroxyl groups of the upper-unit of the dimer are crucially important for strong and effective activity.

Antioxidant capacity and cytotoxicity of sulfated polysaccharide TLH-3 from Tricholoma lobayense

Polysaccharide TLH-3 from the fruit body of Tricholoma lobayense Heim has shown outstanding antioxidant activity. In order to further explore it, TLH-3 was successfully modified to obtain a sulfated derivative (STLH-3). The chemical characteristics of STLH-3 and TLH-3 were determined by high performance liquid chromatography and infrared spectroscopy. Antioxidant activity and cytotoxicity of the samples were investigated in vitro. The antioxidant activities of STLH-3 were significantly improved. In the four indicators of antioxidant activity, the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion scavenging activities of STLH-3 have exceeded that of Vitamin C (Vc). The cytotoxicity against tumor cells including human cervical carcinoma cell line (HeLa) and human breast cancer cell line (MCF-7) of STLH-3 was obviously stronger than that of TLH-3. STLH-3 had no toxic on human embryonic lung fibroblasts (HELF) cells. These results suggested that STLH-3 would be a promising bioactive macromolecule for potential applications in the field of health care and pharmaceutical.

Amantelides A and B, Polyhydroxylated Macrolides with Differential Broad-Spectrum Cytotoxicity from a Guamanian Marine Cyanobacterium.

Cytotoxicity-guided fractionation of a Guamanian cyanobacterial collection yielded the new compounds amantelides A (1) and B (2). These polyketides are characterized by a 40-membered macrolactone ring consisting of a 1,3-diol and contiguous 1,5-diol units and a tert-butyl substituent. Amantelide A (1) displayed potent cytotoxicity with submicromolar IC₅₀ against HT29 colorectal adenocarcinoma and HeLa cervical carcinoma cell lines. Acetylation of the hydroxy group at C-33 in 2 caused a close to 10-fold decrease in potency. Exhaustive acetylation of the hydroxy groups abrogated the antiproliferative activity of amantelide A (1) by 20-67-fold. Further bioactivity assessment of 1 against bacterial pathogens and marine fungi indicated a broad spectrum of bioactivity.

Novel in situ biosynthesized fluorescent zinc nanoclusters for specific cellular bio-imaging

Abstract It is well known that zinc ions play an indispensable role in the structure and function of a large number of biological process and relevant bio-macromolecules. When some cancers occurred, the relevant concentration of zinc ions considerably decreased. Since cancer cells have a completely different redox homeostasis from normal cells, in this contribution, we have explored the possibility of bio-imaging or labeling of cancer cells through the in situ biosynthesized zinc nanoclusters by cancerous cells. The results demonstrate that we can readily realize the in vivo fluorescent bio-imaging of cancer cells through the in situ biosynthesis of the biocompatible zinc nanoclusters from cancerous cells ( i.e. , Hela cervical carcinoma cell line and others) when target cells cultured with micromolar zinc gluconate solutions.

Doxycycline Induces Apoptosis and Inhibits Proliferation and Invasion of Human Cervical Carcinoma Stem Cells.

BackgroundCancer stem cells (CSCs) are proposed to be responsible for high recurrence rate in cervical carcinoma. Reagents that can suppress the proliferation and differentiation of CSCs would provide new opportunities to fight against tumor recurrence. Doxycycline has been reported as a potential anti-cancer compound. However, few studies investigated its inhibitory effect against cervical cancer stem cells.MethodsHeLa cells were cultured in cancer stem cell conditional media in a poly-hema-treated dish. In this non-adhesive culture system, HeLa cells were treated with cisplatin until some cells survived and formed spheroids, which were then collected and injected into the immunodeficient mice. Cisplatin was administered every three days for five times. The tumor xenografts with CSC enrichment were cultured in cancer stem cell specific medium again to form tumorsphere, which we called HeLa-CSCs. Expression of cancer stem cell markers in HeLa-CSCs was measured by flow cytometry and qPCR. HeLa-CSCs were then treated with doxycycline. Proliferation and differentiation rates were determined by the size of spheres formed in vitro and tumor formed in vivo.ResultsWe developed a new strategy to selectively enrich CSCs from human cervical carcinoma cell line HeLa, and these HeLa-CSCs are CD133+/CD49f+ cell populations with significantly enhanced expression of stem cell markers. When these HeLa-CSCs were treated with doxycycline, the colony formation, proliferation, migration and invasion, and differentiation were all suppressed. Meanwhile, stem cell markers SOX-2, OCT-4, NANOG, NOTCH and BMI-1 decreased in doxycycline treated cells, so as the surface markers CD133 and CD49f. Furthermore, proliferation markers Ki67 and PCNA were also decreased by doxycycline treatment in the in vivo xenograft mouse model.ConclusionsCancer stem cells are enriched from sphere-forming and chemoresistant HeLa-derived tumor xenografts in immunodeficient mice. Doxycycline inhibits proliferation, invasion, and differentiation, and also induces apoptosis of these HeLa-CSCs in vitro and in vivo.

A ruthenium(II) complex inhibits tumor growth in vivo with fewer side-effects compared with cisplatin

The antitumor activity of a ruthenium(II) polypyridyl complex, Δ-[Ru(bpy)2(HPIP)](ClO4)2 (Δ-Ru1, where bpy=2,2′-bipyridine, HPIP=2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline), was evaluated. The in vivo experiments showed that Δ-Ru1 inhibited the growth of a human cervical carcinoma cell line (HeLa) xenotransplanted into nude mice with efficiency similar to that of cisplatin. Histopathology examination of the tumors from treated xenograft models was consistent with apoptosis in tumor cells. Importantly, in striking contrast with cisplatin, Δ-Ru1 did not cause any detectable side effects on the kidney, liver, peripheral neuronal system, or the hematological system at the pharmacologically effective dose. The preclinical studies reported here provide support for the clinical use of Δ-Ru1 as an exciting new drug candidate with lower toxicity than cisplatin, endowed with proapoptotic properties.

Selenium Dioxide Induced Apoptosis in Cervical Cancer Cells via Regulating Apoptosis-related Let-7a MicroRNA and Proteins

Aim: To investigate the effects of selenium dioxide (SeO2) on the apoptosis and the involved epigenetic mechanisms in two cervical cancer cell lines. Methods: Human cervical carcinoma cell lines HeLa and CaSki were treated with 1.875–30 µmol/L SeO2 for 24 h. Morphological changes were observed by optical microscope; anti-proliferative effects were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; flow cytometry (FCM) was employed to detect the cell apoptosis; real-time polymerase chain reaction was used to detect the expression of let-7a; and the levels of caspase-3 and p53 proteins in HeLa cells were determined by Western blot analysis. Differences between the mean values of multiple groups were analyzed by one-way analysis of variance or Student's t test. P Results: Compared to control group, obvious morphological changes were observed in the SeO2 group. SeO2 significantly (P Conclusion: SeO2 showed anti-tumor properties via apoptotic pathway by up-regulating the expressions of let-7a, as well as caspase-3 and p53 in cervical cancer cells.

Efficient and mild one-pot synthesis of (E)-8′-arylidene-5′,6′,7′,8′-tetrahydrospiro[oxindole-3,4′-pyrano[3,2-c]pyridin] derivatives with potential antitumor activity

A mild and efficient cyclization procedure for the synthesis of (E)-8′-arylidene-5′,6′,7′,8′-tetrahydrospiro[oxindole-3,4′-pyrano[3,2-c]pyridin] derivatives was achieved via one-pot three-component condensation of isatins, malononitrile and (E)-3-arylidene-1-methylpiperidin-4-ones using piperidine as an efficient catalyst and ethanol as an environmentally benign solvent. The in vitro antitumor activity of these compounds was evaluated in human cervical carcinoma cell line (Hela), human liver hepatocellular carcinoma cell line (HepG2), and human breast carcinoma cell line (MDA-MB-231).

Quaternized Chitosans as Gene Delivery Carriers: Effect of Degree of Quaternization

The objective of this study was to investigate the transfection efficiency of quaternized chitosan or trimethylated chitosans (TMCs) using the plasmid DNA encoding green fluorescent protein (pEGFP-C2) on human cervical carcinoma cell line (HeLa cells). The factors affecting the transfection efficiency, e.g. degree of quaternization (DQ) and polymer/DNA weight ratio were evaluated. The results revealed that the complexes of TMC30 with DNA had the highest transfection efficiency and safety followed by the complexes of TMC60 and TMC94, respectively. Increasing the DQ of chitosan not only improve the efficiency of gene delivery, but also increase cytotoxicity. In conclusion, TMC30 showed elevated potential as a gene carrier by efficient DNA condensation and mediated the highest level of gene transfection with negligible cytotoxicity in HeLa cells.

Cytotoxicity and Antimicrobial Studies of Silver Nanoparticles Synthesized Using Psidium guajava L. Extract

Polyphenols in guava extract act as reducing as well as stabilizing agent to produce silver nanoparticles. UV-Visible spectra at 420 nm confirmed the formation of silver nanoparticles. The Fourier transform infrared spectroscopy analysis was carried out to identify the functional groups responsible for the bio-reduction of silver. The morphology of silver nanoparticles was confirmed by high-resolution transmission electron microscopy. Ag nanoparticles showed excellent antibacterial activity against Staphylococcus mutans, Bacillus cereus, Eschericia coli, Staphylococcus aureus, and Staphylococcus typhii. In our study, cervical carcinoma HeLa cell line was used to observe the efficacy of cancer cell killing ability of silver nanoparticles.

Synthesis, cytotoxic activity, and computational analysis of N10-substituted acridone analogs

A series of twenty N10-substituted acridone derivatives were synthesized, tested for in vitro cytotoxic activity, and analyzed computationally to predict their multi-drug resistance (MDR) modulation potential. All synthesized N10-substituted acridone analogs were tested for their in vitro cytotoxic activity against human breast adenocarcinoma (MCF-7), human small cell lung carcinoma (A-549), human colon adenocarcinoma (HT-29), and human cervical epithelioid carcinoma (HeLa) cell lines by MTT assay. The compounds were observed to be inactive against the HT-29 cell line. Among the synthesized compounds, compound 14 showed good in vitro activity against MCF-7, A-549, and HeLa cancer cell lines in the low micromolar (µM) range as compared to other compounds. Additionally, in silico study was performed to check the multi-drug resistance modulator (MDR) effect of these compounds using docking simulations in the ATP binding site of P-gp. The results of docking simulation displayed important interactions of molecules 6, 7, 13, 14, 19, and 20 in the active site of this protein and proposed their dual action, i.e., anti-cancer and MDR modulation.

Bioactive Steroids from a Marine-Derived Fungus Penicillium sp. from the South China Sea

Marine organisms have been found to be a source of steroids, particularly in terms of unique side-chain structures and unusual functionalization [1]. Marine steroids are often found in highly oxygenated forms, and such steroids sometimes show a variety of biological and pharmacological activities [2]. Despite the number of marine-derived steroids that have been found to date, marine-derived fungi appear to be an infertile source of novel bioactive steroids [3]. In the course of our ongoing investigation on bioactive secondary metabolites from marine fungi in the South China Sea, a sponge-derived fungus Penicillium sp. attracted our attention because of the fact that the EtOAc extract of the fungal culture showed pronounced cytotoxic activity against K562 chronic leukemia cell line. Investigation of the active extract of this fungus led to the isolation of 12 steroids (1–12). The structures of these steroids were determined on the basis of their 1H NMR, 13C NMR, and ESI-MS spectroscopic data, and by comparison with those previously reported in the literature, as six steroids with ketone carbonyl groups, dankasterone A (1) [4], dankasterone B (2) [4], 3 ,15 -dihydroxyl-(22E,24R)-ergosta-5,8(14),22-trien-7-one (3) [5], 3 ,15 -dihydroxyl-(22E,24R)-ergosta-5,8(14),22-trien-7-one (4) [5], 6 -hydroxy-ergosta-4,7,22-trien-3-one (5) [6], and 6 -hydroxy-stigmast-4-en-3-one (6) [7]; two epoxy-ergosterols, 5 ,6 -epoxy-(22E,24R)-ergosta-8(14),22-diene-3 ,7 -diol (7) [8] and 5 ,6 -epoxy-(22E,24R)-ergosta-8,22-diene-3 ,7 -diol (8) [8]; two epidioxy-ergosterols, 5 ,8 -epidioxy-ergosta6,22E-dien-3 -ol (9) [9] and 5 ,8 -epidioxy-ergosta-6,9,22E-trien-3 -ol (10) [9]; and two polyoxygenated sterols, 3 ,5 -dihydroxy-6 -methoxyergosta-7,22-diene (11) [10], and 3 ,5 ,6 ,9 -tetrahydroxyergosta-7,22-diene (12) [10]. The cytotoxic activity of all isolated compounds was evaluated against human promyelocytic leukemia HL-60, human lung carcinoma A-549, chronic leukemia K562, and human cervical carcinoma Hela cell lines. Compound 1 showed pronounced cytotoxic activity against HL-60, Hela, and K562 with IC50 values of 0.78, 4.11, and 7.57 M, respectively, especially to HL-60, which was stronger than that of the positive control adriamycin (IC50 0.98 M). Compound 2 also exhibited strong growth inhibition against HL-60, Hela, and K562 with IC50 values of 3.25, 4.74, and 7.89 M. Compounds 3 and 4 showed significant cytotoxic activity against K562 with IC50 values of 4.38 and 5.54 M, respectively. These results suggested that ketone carbonyl groups in compounds 1–4 should play an important role for enhancement of cancer cell growth inhibition. The antibacterial activity of all isolated compounds was also evaluated with a panel of pathogenic bacteria, including Gram-positive Staphylococcus aureus, S. albus, Bacillus cereus, Micrococcus tetragenus, and Kocuria rhizophila, and Gram-negative Escherichia coli, Vibrio parahaemolyticus, V. anguillarum, and Pseudomonas putida (Table 1). The results indicated that the isolated steroids (1–5, 7–11) exhibited widely significant antibacterial effects against most of pathogenic bacteria except for S. albus and V. parahaemolyticus. Among these steroids, compound 1 was found to be the most active and showed a broad spectrum of antibacterial activity, while compounds 2–5 and 7–11 exhibited selective antibacterial activity. In particular, compounds 1, 4, 7, and 8 showed strong antibacterial activity against V. anguillarum with MIC values of 0.39, 0.78, 0.78, and 0.39 M, respectively, which were stronger than or equivalent to that of the positive control ciprofloxacin. It is noteworthy that the activity of 1 was stronger than that of 2, and the only difference between their structures was the absence of double bond at C-4/C-5 in 2, indicating that the double bond at C-4/C-5 in 13(14 8)abeo-8-ergostane had a significant effect on the antibacterial activity. The results of antibacterial activity also suggested that the ketone carbonyl groups, epoxy rings, and peroxy groups in steroids played apparent role on the antibacterial activity. Moreover, compound 12 with four hydroxy groups was less active than 11, suggesting that the simultaneous presence of several hydroxy groups caused loss of activity.

Dual pH and temperature stimuli-responsive magnetic nanohydrogels for thermo-chemotherapy.

Dual stimuli pH and temperature-responsive nanohydrogels based on poly(N-isopropylacrylamide)-chitosan have been synthesized. Fe3O4 magnetic nanoparticles (NPs) (-12 nm) have been incorporated into hydrogels to achieve temperature optimized magnetic nanohydrogel (MNHG) for magnetic hyperthermia with lower critical solution temperature, LCST > 42 degrees C. The composite was further investigated for its potential application in drug delivery and in vitro cancer cell cytotoxicity. Water-bath assisted drug release studies were carried out using anti-cancer drug doxorubicin (DOX) in acetate buffer medium (pH - 4.6) to mimic tumor cell environment which is slightly acidic in nature. The pH and temperature responsiveness of the system was demonstrated by DOX release under different conditions. The released amount of DOX was found to be nearly 4 microg/mg above hyperthermia temperature (-42 degrees C) as opposed to only 1.9 microg/mg of MNHG at physiological temperature (37 degrees C) under acidic environment (pH - 4.6). Further, AC magnetic field (AMF) induced heating of NPs entrapped inside hydrogels showed appreciable reduction of cell population in human breast (MCF-7) and cervical carcinoma (HeLa) cell lines for given duration of field exposures. Quantitatively, death percentages of HeLa cells were nearly 35 and 45% while for MCF-7, these were 20 and 70% when exposed to AMF for 10 and 30 min, respectively. Further the cell killing efficacy of MNHG loaded with DOX was assessed under AMF using HeLa cell lines. The AMF induced heat triggered DOX release from the MNHG which enhances the cell death up to 85% due to combined effect of thermo-chemotherapeutics. The present system with both pH and temperature responsivity serves as a promising candidate for a combination therapy.

Protein, free amino acid, phenolic, β-carotene, and lycopene content, and antioxidative and cancer cell inhibitory effects of 12 greenhouse-grown commercial cherry tomato varieties

The content of water, free amino acids, amino acid metabolites, crude protein, the carotene pigments β-carotene and lycopene, and 9 characterized and 2 incompletely characterized individual phenolic (flavonoid) compounds of 12 greenhouse-grown cherry tomato varieties of various colors (green, yellow, orange, red, and black) was determined using HPLC and LC/MS methods. The phenolic content of the cherry tomatoes per unit weight is 3-4 times greater than reported values for large-sized tomatoes. Antioxidative effects using the ABTS and FRAP assays and cancer-cell-inhibiting effects against 2 normal (Chang liver and Hel299 lung) and 3 human cancer (lung A549; liver HepG2; and cervical HeLa) cell lines using the MTT cell viability assay were also determined. Lycopene inhibited all the cell lines, but showed strong activity against the cervical carcinoma and the lung cancer cells. The tomato extracts showed inhibition at the higher doses. The HeLa cervical carcinoma cell line was most inhibited by the pure compounds, and the HeLa or the HepG2 cells lines were the most inhibited by the tomato extracts. The results demonstrate wide-ranging differences as well as similarities in the content of nutritional and bioactive compounds in cherry tomatoes, and suggest that such knowledge can benefit consumers.

A Novel Mechanism by Which Tissue Transglutaminase Activates Signaling Events That Promote Cell Survival

Tissue transglutaminase (tTG) functions as a GTPase and an acyl transferase that catalyzes the formation of protein cross-links. tTG expression is frequently up-regulated in human cancer, where it has been implicated in various aspects of cancer progression, including cell survival and chemo-resistance. However, the extent to which tTG cooperates with other proteins within the context of a cancer cell, versus its intrinsic ability to confer transformed characteristics to cells, is poorly understood. To address this question, we asked what effect the ectopic expression of tTG in a non-transformed cellular background would have on the behavior of the cells. Using NIH3T3 fibroblasts stably expressing a Myc-tagged form of tTG, we found that tTG strongly protected these cells from serum starvation-induced apoptosis and triggered the activation of the PI3-kinase/mTOR Complex 1 (mTORC1)/p70 S6-kinase pathway. We determined that tTG forms a complex with the non-receptor tyrosine kinase c-Src and PI3-kinase, and that treating cells with inhibitors to block tTG function (monodansylcadaverine; MDC) or c-Src kinase activity (PP2) disrupted the formation of this complex, and prevented tTG from activating the PI3-kinase pathway. Moreover, treatment of fibroblasts over-expressing tTG with PP2, or with inhibitors that inactivate components of the PI3-kinase pathway, including PI3-kinase (LY294002) and mTORC1 (rapamycin), ablated the tTG-promoted survival of the cells. These findings demonstrate that tTG has an intrinsic capability to stimulate cell survival through a novel mechanism that activates PI3-kinase signaling events, thus highlighting tTG as a potential target for the treatment of human cancer.

Nonionic Surfactant Vesicles Composed of Novel Spermine-Derivative Cationic Lipids as an Effective Gene Carrier In Vitro

In the present study, nonionic surfactant vesicles (niosomes) formulated with Span 20, cholesterol, and novel synthesized spermine-based cationic lipids with four hydrocarbon tails in a molar ratio of 2.5:2.5:1 were investigated as a gene carrier. The effects of the structure of the cationic lipids, such as differences in the acyl chain length (C14, C16, and C18) of the hydrophobic tails, as well as the weight ratio of niosomes to DNA on transfection efficiency and cell viability were evaluated in a human cervical carcinoma cell line (HeLa cells) using pDNA encoding green fluorescent protein (pEGFP-C2). The niosomes were characterized both in terms of morphology and of size and charge measurement. The formation of complexes between niosomes and DNA was verified with a gel retardation assay. The transfection efficiency of these cationic niosomes was in the following order: spermine-C18 > spermine-C16 > spermine-C14. The highest transfection efficiency was obtained for transfection with spermine-C18 niosomes at a weight ratio of 10. Additionally, no serum effect on transfection efficiency was observed. The results from a cytotoxicity and hemolytic study showed that the cationic niosomes were safe in vitro. In addition, the cationic niosomes showed good physical stability for at least 1 month at 4°C. Therefore, the cationic niosomes offer an excellent prospect as an alternative gene carrier.