HepG2 Cell Resistance against Camptothecin from a Lysosomal Drug Delivery

Lee, Hoyeon; Uhm, Soojin; Shin, Jung Won; Jeon, Hosang; Dongbang, Sun; Jung, Hyo Sung; Na, Yun-Cheol; Kang, Chulhun; Kim, Jong Seung

doi:10.1002/asia.201500913

Cited by 5 publications

(1 citation statement)

References 24 publications

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“…Another possible reason for not observing any effect of fructose exposure on CS activity could be due to the type of in vitro model used in the study (L6 versus HepG2 cells). L6 myotubes are mouse cells, whereas HepG2 cells are human liver carcinoma cells that have a tendency to be resistant to a variety of stimuli [15,16], and they have an upregulated carbohydrate metabolism [17,18]. To this end, another study has shown that in a model of HepG2 mitochondrial dysfunction, CS activity remained unaltered despite the presence of a pathophysiologic stimulus [19].…”

Section: Discussionmentioning

confidence: 99%

Fructose impairs mitochondrial respiration and substrate utilization in hepatocytes via the enzyme, glutamate oxaloacetate transaminase

Madlala¹,

Maarman²,

Ojuka³

2018

Integr Food Nutr Metab

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Excess fructose associates with increased production of reactive oxygen species (ROS) that inhibits enzymes such as aconitase, which should affect mitochondrial metabolism. Yet there is a lack of studies investigating the impact of excess fructose on mitochondrial metabolic pathways and substrate utilization. We evaluated the impact of excess fructose on hepatocyte mitochondrial enzymes; citrate synthase (CS), aconitase and glutamate-oxaloacetate transaminase (GOT). Also, highresolution using complex I-linked substrates [pyruvate+malate (PM), glutamate+malate (GM) and PGM]. Fructose decreased the activities of aconitase and GOT by 35% and 47% respectively. Respiration at Leak, OXPHOS and ETS states were reduced with GM but not PM or PGM. Thus, excess fructose inhibits GOT activity, reduced mitochondrial leak respiration, OXPHOS and ETS capacity. These changes were observed with complex-1 linked respiration (substrates GM). Therefore, fructose impairs mitochondrial respiration and substrate utilization via the enzyme GOT.lines were initially propagated in 25 cm 2 flasks (Bibby Sterilin, Stone, Staffordshire, UK), at 37 °C in 5 mL DMEM (Gibco BRL, Inchinnan, Scotland) containing 10% (v/v) fetal bovine serum, 20 mM HEPES, 10 mM NaHCO 3 , 100 μg mL -1 penicillin G, and 100 μg mL -1 streptomycin sulfate (Whittaker Bioproducts, Walkersville, MD, USA) at pH 7.5. Cells were incubated for 24 h to permit attachment and grown to semiconfluence and passaged 1:3 every 4-5 days. One group of cells received normal growth medium (control group, DMEM for 72 hours), while the second group were exposed to growth medium supplemented with excess fructose (15 mM, 72 hours) as previously reported [6]. Enzyme activity measurementsSample preparation: HepG2 cells were homogenised in extraction buffer (0.1 M Tris-HCl; 15 mM Tricarballylic acid; pH 7.8) and incubated on ice for 20 min. The homogenate was centrifuged at 10 000 rpm for 20 min and the supernatant was used as a sample for further experimentation. Subsequent enzyme assays were performed according to modified protocols previously described by Wang et al. [11]. Citrate synthase: The following components were added in a cuvette: 473 µl of citrate synthase buffer (0.1 M Tris-HCl, 1.25 mM 5,5'-dithiobis-[2-nitrobenzoic acid] in deionized water, pH 8.0), 2 µl of sample and 25 µl of Oxaloacetate-Acetyl-CoA solution (50 mM Madlala HP (2018) Fructose impairs mitochondrial respiration and substrate utilization in hepatocytes via the enzyme, glutamate oxaloacetate transaminase

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Section: Discussionmentioning

confidence: 99%

Fructose impairs mitochondrial respiration and substrate utilization in hepatocytes via the enzyme, glutamate oxaloacetate transaminase

Madlala¹,

Maarman²,

Ojuka³

2018

Integr Food Nutr Metab

View full text Add to dashboard Cite

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A Lysosome‐Targeting Fluorescence Off‐On Probe for Imaging of Nitroreductase and Hypoxia in Live Cells

Zhou

Shi

et al. 2016

Chemistry An Asian Journal

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A lysosome-targeting fluorescent off-on probe has been developed by one-step synthesis for detecting lysosomal nitroreductase and hypoxia. The probe is constructed by incorporating morpholine (a lysosome-targeting unit) into 4-nitro-1,8-naphthalimide (as a fluorochrome and specific substrate for nitroreductase), and the detection mechanism is based on the nitroreductase-catalyzed reduction of the probe to 4-amino-1,8-naphthalimide, accompanied by a large fluorescence enhancement at a wavelength of 543 nm. The probe shows an accurate lysosome-targeting ability with high selectivity and sensitivity to nitroreductase (detection limit: 2.2 ng mL ). Notably, the probe has been used to image the change of lysosomal nitroreductase in live cells during hypoxia, revealing that the increase of nitroreductase in lysosomes may be smaller than that in the cytoplasm. In addition, the probe is expected to be useful for studying the function of nitroreductase in the acidic organelle of lysosomes.

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Lysosome-targeting red fluorescent probe for broad carboxylesterases detection in breast cancer cells

Sun

Zhou²,

Sun

et al. 2022

Chinese Chemical Letters

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HepG2 Cell Resistance against Camptothecin from a Lysosomal Drug Delivery

Cited by 5 publications

References 24 publications

Fructose impairs mitochondrial respiration and substrate utilization in hepatocytes via the enzyme, glutamate oxaloacetate transaminase

Fructose impairs mitochondrial respiration and substrate utilization in hepatocytes via the enzyme, glutamate oxaloacetate transaminase

A Lysosome‐Targeting Fluorescence Off‐On Probe for Imaging of Nitroreductase and Hypoxia in Live Cells

Lysosome-targeting red fluorescent probe for broad carboxylesterases detection in breast cancer cells

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