Selective cytotoxicity of goniothalamin against hepatoblastoma HepG2 cells

Liver cancer has become one of the major types of cancer with high mortality and liver cancer is not responsive to the current cytotoxic agents used in chemotherapy. The purpose of this study was to examine the in vitro cytotoxicity of goniothalamin on human hepatoblastoma HepG2 cells and normal liver Chang cells. The cytotoxicity of goniothalamin against HepG2 and liver Chang cell was tested using MTT cell viability assay, LDH leakage assay, cell cycle flow cytometry PI analysis, BrdU proliferation ELISA assay and trypan blue dye exclusion assay. Goniothalamin selectively inhibited HepG2 cells [IC?? = 4.6 (±0.23) μM in the MTT assay; IC?? = 5.20 (±0.01) μM for LDH assay at 72 hours], with less sensitivity in Chang cells [IC?? = 35.0 (±0.09) μM for MTT assay; IC?? = 32.5 (±0.04) μM for LDH assay at 72 hours]. In the trypan blue dye exclusion assay, the Viability Indexes were 52 ± 1.73% for HepG2 cells and 62 ± 4.36% for Chang cells at IC?? after 72 hours. Cytotoxicity of goniothalamin was related to inhibition of DNA synthesis, as revealed by the reduction of BrdU incorporation. At 72 hours, the lowest concentration of goniothalamin (2.3 μL) retained 97.6% of normal liver Chang cells proliferation while it reduced HepG2 cell proliferation to 19.8% as compared to control. Besides, goniothalamin caused accumulation of hypodiploid apoptosis and different degree of G2/M arrested as shown in cell cycle analysis by flow cytometry. Goniothalamin selectively killed liver cancer cell through suppression of proliferation and induction of apoptosis. These results suggest that goniothalamin shows potential cytotoxicity against hepatoblastoma HepG2 cells.     

Tadehaginoside modulates lipogenesis and glucose consumption in HepG2 cells

Tadehaginoside (TS) is a phenylpropanoid glycoside found in Tadehagi triquetrum, a medicinal plant with multiple biological activities. This study investigated the effect of TS on lipogenesis and glucose consumption in HepG2 cells. Treatment with TS inhibited lipid accumulation in a dose-dependent manner. This inhibition was closely associated with the downregulation of lipogenic genes such as SREBP-1a, SREBP-2 and their downstream targets (FAS, ACC, HMGR) and the upregulation of lipolytic gene PPARα as revealed by real-time quantitative PCR. Further investigation showed that TS significantly stimulated glucose consumption by HepG2 cells and glucose uptake by C2C12 myotubes, which could be partially explained by the upregulation of PPARγ. Collectively, these results clearly indicate that TS is an effective regulator of lipogenesis and glucose consumption, which could be useful in treatment of obesity and diabetes.     

Using aptamers to visualize and capture cancer cells

Since diseased cells exist in exceedingly low concentration at the early stage of cancer, highly sensitive imaging and detection methods are required. By improving the methods for capturing and visualizing cancer cells, clinicians can diagnose metastatic relapse, stratify patients for therapeutic purposes, monitor response to drugs and therapies, and track tumor progression. Therefore, using advanced biotechnological and analytical methods combined with cell-SELEX (systematic evolution of ligands by exponential enrichment)-based aptamers, we improved the capture and visualization of diseased cells in a manner that is inexpensive, simple, sensitive, and fast. This multiplexed cancer detection platform therefore improves our control over a range of clinical exigencies, including cancer diagnosis, therapeutic modalities, and drug delivery systems.     

Prenylated flavonoids and dihydrophenanthrenes from the leaves of Epimedium brevicornu and their cytotoxicity against HepG2 cells

Phytochemical study on the leaves of Epimedium brevicornu finally led to the isolation of four prenylated flavonoids (1–4) and three dihydrophenanthrenes (5–7), of which 1, 2, 5 and 7 were new compounds. The structures of these compounds were established mainly by spectroscopic techniques, including NMR spectroscopy and mass spectrometry. These isolates exhibited the cytotoxic activities against HepG2 cells with the IC₅₀ values of 32.8–87.3 μM.     

Cucurbitane triterpenoids from Momordica charantia and their cytoprotective activity in tert-butyl hydroperoxide-induced hepatotoxicity of HepG2 cells

Two novel pentanorcucurbitane triterpenes, 22-hydroxy-23,24,25,26,27-pentanorcucurbit-5-en-3-one (1) and 3,7-dioxo-23,24,25,26,27-pentanorcucurbit-5-en-22-oic acid (2) together with a new trinorcucurbitane triterpene, 25,26,27-trinorcucurbit-5-ene-3,7,23-trione (3) were isolated from the methyl alcohol extract of the stems of Momordica charantia. The structures of the new compounds were elucidated by spectroscopic methods. Compounds 2 and 3 showed potent cytoprotective activity in tert-butyl hydroperoxide (t-BHP)-induced hepatotoxicity of HepG2 cells.     

Characterizing doxorubicin-induced apoptosis in HepG2 cells using an integrated microfluidic device

Apoptosis has now established its importance in numerous areas of biology and is recently receiving great attention as an important topic related to the development of diseases. In this work, an integrated microfluidic device was developed to characterize doxorubicin-induced apoptosis in human hepatocellular carcinoma (HepG2) cells. A continuous concentration gradient of stimulator (doxorubicin) was generated in the upstream network and used to perfuse downstream cultured HepG2 cells. The appropriate fluorescent dyes were introduced into cells from the inlets connected to the cell culture chambers, allowing one to distinguish apoptotic cells from nonapoptotic or necrotic cells. The resultant fluorescence of cellular population was monitored and quantified with single-cell resolution to infer the apoptosis process being studied. The feasibility of studying apoptosis was demonstrated by measuring several apoptotic events, including morphological alterations, plasma membrane phosphatidylserine externalization, and mitochondrial membrane potential collapse. This microfluidic device, integrating the cell culture, stimulation, staining, and washing steps into a single device, can simultaneously generate a number of experimental conditions and investigate multiple parameters relating stimulation to apoptosis. It offers a unique platform to characterize various cellular responses in a high-throughput fashion, which is otherwise impossible with conventional methods.     

A new flavonol triglycoside derived from Anoectochilus elwesii on stimulating glucose uptake in insulin-induced human HepG2 cells

A novel flavonol triglycoside (4), isorhamnetin-3-O-β-d-glucopyranosyl (1→2)-α-l-rhamnopyranosyl (1→6)-β-d-glucopyranoside, named elwesoside A, together with six known flavonols (1–3, 5–7) was isolated from Anoectochilus elwesii (Clarke ex Hook. f.) King et Pantl. and its structure was elucidated by extensive spectroscopic methods and comparison with the literature data. All compounds were first reported in this plant and two of them (4 and 5) were the first examples of flavonol triglycosides isolated from Anoectochilus genus. The effects of 1–7 were evaluated on insulin-treated human HepG2 cells under high glucose conditions for stimulating glucose uptake activities. The novel compound (4) displayed highly potent dose-dependent effect on the stimulation of glucose uptake in insulin-resistant human HepG2 cells.     

Components from the steamed leaves of Acanthopanax koreanum and their effects on PPAR activity in HepG2 cells

Three ent-kaurane diterpenes (1-3), four lupane-triterpene glycosides (4-7), and an oleanane-triterpene glycoside (8) were isolated from the ethyl acetate and water extracts of the steamed leaves of Acanthopanax koreanum using a combination of various column chromatographies. The structures of the isolates were determined by 1H-, 13C-NMR spectroscopy and mass spectrometry. To investigate the biological effects of the eight compounds (1-8) on peroxisome proliferator-activated receptor gamma (PPARgamma), luciferase reporter assays were used. Among the tested compounds, ent-kaur-16-en-19-oic acid (1), 16alpha-hydroxy-ent-kauran-19-oic acid (2), and 17-hydroxy-ent-kaur-15-en-19-oic acid (3) showed considerable effects on PPARgamma activity, compared with the positive control, troglitazone. To evaluate specificity and sensitivity of the active compounds (1-3) in the regulation of transactivation of PPARs, Gal4-PPARs-LBD luciferase reporter assays were examined. In this study, the three ent-kaurane diterpenes (1-3) were found to up-regulate PPARbeta/delta and PPARgamma activities, whereas they did not activate PPARalpha activity.     

Novel megastigmanes with lipid accumulation inhibitory and lipid metabolism-promoting activities in HepG2 cells from Sedum sarmentosum

Four novel megastigmanes, neosedumosides I (1), II (2), III (3), and IV (4) were isolated from the whole plant of Sedum sarmentosum (Crassulaceae). Absolute stereostructures of these constituents were determined on the basis of chemical and physicochemical evidence. Among them, 1-3 were found to show lipid accumulation inhibitory activity in HepG2 cells. Furthermore, 2 and 3 were found to also show lipid metabolism-promoting activity.     

HepG2 Cell Resistance against Camptothecin from a Lysosomal Drug Delivery

A galactose‐appended drug delivery system released camptothecin (CPT) to lysosomes of HepG2 hepatoma cells, resulting in the cell resistance to the anticancer drug. We found that the resistance to CPT is caused by alteration of the drug release from the prodrug in lysosomes, emphasizing that the final delivery locations may critically influence drug efficacy.     

HepG2 human hepatocarcinoma cells: an experimental model for photosensitization by endogenous porphyrins

Endogenous protoporphyurin IX (PpIX) synthesis after δ-aminolaevulinic acid (ALA) administration occurs in cancer cells in vivo; PpIX, which has a short half-life, may thus constitute a good alternative to haematoporphyrin derivative (HPD) (or Photofrin). This study assesses the ability of the human hepatocarcinoma cell line HepG2 to synthesize PpIX in vitro from exogenous ALA, and compares ALA-induced toxicity and phototoxicity with the photodynamic therapy (PDT) effects of HPD on this cell line.

ALA induced a dose-dependent dark toxicity, with 79% and 66% cell survival for 50 and 100 μg ml⁻¹ ALA respectively after 3 h incubation; the same treatment, followed by laser irradiation (λ = 632 nm, 25 J cm⁻²), induced a dose-dependent phototoxicity, with 54% and 19% cell survival 24 h after PDT. Whatever the incubation time with ALA, a 3 h delay before light exposure was found to be optimal to reach a maximum phototoxicity.

HPD induced a slight dose-dependent toxicity in HepG2 cells and a dose- and time-dependent phototoxicity ten times greater than that of ALA-PpIX PDT. After 3 h incubation of 2.5 and 5 μg ml⁻¹ HPD, followed by laser irradiation (λ = 632 nm, 25 J cm⁻²), cell survival was 59% and 24% respectively at 24 h.

Photoproducts induced by light irradiation of porphyrins absorb light in the red spectral region at longer wavelengths than the original porphyrins. The possible enhancement of PDT effects after HepG2 cell incubation with ALA or HPD was investigated by irradiating cells successively with red light (λ = 632 nm) and light (λ = 650 nm). The total fluence was kept constant at 25 J cm⁻². For both HPD and ALA-PpIX PDT, phototoxicity was lower when cells were irradiated for increased periods with λ = 650 nm light than with λ = 632 nm light alone. This suggests that any photoproducts involved either have a short life or are poorly photoreactive.

Not all cell lines can synthesize PpIX after ALA incubation. HepG2 cells, which can synthesize enzymes and precursors of endogenous porphyrin synthesis, represent a good in vitro model for experiments using ALA-PpIX PDT. In addition, ALA-PpIX PDT may represent a new, specific treatment for hepatocarcinomas.     

Ultrasensitive determination of intracellular superoxide in individual HepG2 cells by microfluidic chip electrophoresis

A microchip electrophoresis method was established for the determination of intracellular superoxide (O₂⁻) in individual HepG2 cells. Dihydroethidium (DHE) was used as the specific fluorescent probe to react with intracellular O₂⁻ to form the fluorescent 2-hydroxyethidium. Excellent resolution between 2-hydroxyethidium and ethidium cation (E⁺) can be achieved within 20 s. E⁺ was reported to be generated from photochemical oxidation of DHE and interfere the determination of O₂⁻ with fluorescence microscopic technique. An extremely low detection limit of 2.0 amol was achieved owing to the minute sample volume and insignificant dispersion effect during microfluidic chip-based electrophoretic separation. Furthermore, only 2-hydroxyethidium peak was detected with the suggested single-cell analysis method, which indicates the photooxidation of DHE to E⁺ could be blocked by isolating either oxygen or light from them.     

Synthetic applications of the carbanion generated from 4,4,4-trifluorobutan-2-one

Synthetic routes for α-trifluoromethylated carbonyl compounds based on the aldol reaction of silylenol ether and the palladium(0) catalyzed reaction using by 4,4,4-trifluorobutan-2-one are described.     

Loosely packed self-assembled monolayers on gold generated from 2-alkyl-2-methylpropane-1,3-dithiols

A series of 2-alkyl-2-methylpropane-1,3-dithiol derivatives with increasing alkyl chain lengths (i.e., CH3(CH2)mC(CH3)[CH2SH]2, where m = 7, 9, 11, 13, 15) were synthesized and used to generate self-assembled monolayers (SAMs) on gold. The resulting monolayers were analyzed by ellipsometry, contact angle goniometry, polarization modulation infrared reflection-absorption spectroscopy, and X-ray photoelectron spectroscopy. These data were compared with those obtained on SAMs on gold derived from normal alkanethiols (CH3(CH2)(m+2)SH) and 2-monoalkylpropane-1,3-dithiols (CH3(CH2)(m)CH[CH2SH]2) having the same number of carbon atoms in the primary chain. The results demonstrate that the 2-alkyl-2-methylpropane-1,3-dithiols generate conformationally disordered monolayer films in which the density of alkyl chains is less than those generated from normal alkanethiols and the 2-monoalkylpropane-1,3-dithiols.     

Selenium methylselenocysteine protects human hepatoma HepG2 cells against oxidative stress induced by tert-butyl hydroperoxide

Selenium methylselenocysteine (Se-MeSeCys) is a common selenocompound in the diet with a tested chemopreventive effect. This study investigated the potential protective effect of Se-MeSeCys against a chemical oxidative stress induced by tert-butyl hydroperoxide (t-BOOH) on human hepatoma HepG2 cells. Speciation of selenium derivatives by liquid chromatography–inductively coupled plasma mass spectrometry depicts Se-MeSeCys as the only selenocompound in the cell culture. Cell viability (lactate dehydrogenase) and markers of oxidative status—concentration of reduced glutathione (GSH) and malondialdehyde (MDA), generation of reactive oxygen species (ROS) and activity of the antioxidant enzymes glutathione peroxidase (GPx) and glutathione reductase (GR)—were evaluated. Pretreatment of cells with Se-MeSeCys for 20 h completely prevented the enhanced cell damage, MDA concentration and GR and GPx activity and the decreased GSH induced by t-BOOH but did not prevent increased ROS generation. The results show that treatment of HepG2 cells with concentrations of Se-MeSeCys in the nanomolar to micromolar range confers a significant protection against an oxidative insult.     

A dual near-infrared pH fluorescent probe and its application in imaging of HepG2 cells

A dual near-infrared pH fluorescent probe has been designed, synthesized and applied to HepG2 cells, with a pK(a) value of 5.14 under acidic conditions and 11.31 under basic conditions, which is valuable for studying acidic organelles in living cells and pH changes in chemical systems.     

Regioselective formation of alkylidenecyclopropanes from 2-substituted cyclobutylidenes generated from geminal dibromocyclobutanes and methyllithium

Four different 2-substituted geminal dibromocyclobutanes were reacted with methyllithium at -78 degrees C. In contrast to previous studies using diazocyclobutanes as carbene precursors at temperatures above 200 degrees C via reaction of the corresponding tosylhydrazone sodium salts, the organometallic route in each case produces only an alkylidenecyclopropane that could be isolated in good yields. B3LYP calculations were employed to rationalize the observed regioselective ring contraction of the generated cyclobutyliden(oid)s. [reaction: see text]     

In-vitro cytotoxicity of synthesized phthalide-fused indoles and indolines against HL-60 and HepG2 cells

Phthalide derivatives bearing indole or indoline moieties were successfully synthesized via eco-friendly method and were evaluated for their antiproliferative activity on HL-60 and HepG2 cell lines in vitro. At a final concentration of 100 μM, most of the compounds showed moderate potency on both the cell lines tested. Compound 3b bearing 5-chloro substituted indoline had the best potency against HL-60 and HepG2 cell lines with IC₅₀ values of 45.4 and 57.7 μM, respectively. It was also found that replacement of a conjugated indoline to indole moiety gave better antiproliferative activity on HL-60 cells by almost two-fold. Morphological observation demonstrated numerous fragmented nuclei which are indicative of apoptosis. Molecular docking studies predicted non-covalent interactions and H-bonding of selected compounds with the P2 binding hot spot of the anti-apoptotic protein, Bcl-2, formed by Asp108, Phe109, Met112, Leu134, Arg143, Ala146 and Val153. Overall, our work highlights the potential of synthesized phthalide-fused indoles or indolines as antitumor agents.