γ-Glutamylcysteine synthetase (γ-GCS) as a target for overcoming chemo- and radio-resistance of human hepatocellular carcinoma cells

Li Ching Lin, Chi Fen Chen, Chun Te Ho, Jun Jen Liu, Tsan Zon Liu, Chi Liang Chern

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Aims: This study uncovered that the genetically endowed intracellular glutathione contents (iGSH) regulated by the catalytic subunit of γ‑glutamylcysteine synthetase heavy chain (γ‑GCSh) as a prime target for overcoming both the inherited and stimuli-activated chemo- and radio-resistance of hepatocellular carcinoma (HCC) cells. Main methods: Reactive oxygen species (ROS) production and mitochondrial membrane potential (Δψm) were determined by the probe-based flow cytometry. The TUNEL assay was used as an index of radio-sensitivity and the MTT assay was used as an index of chemo-sensitivity against various anti-cancer agents. iGSH and γ‑GCSh activity were measured by HPLC methods. γ‑GCSh-overexpressing GCS30 cell line was established by tetracycline-controlled Tet-OFF gene expression system in SK-Hep-1 cells. Key findings: The relative radio-sensitivities of a panel of five HCC cells were found to be correlated negatively with both the contents of iGSH and their corresponding γ‑GCSh activities with an order of abundance being Hep G2 > Hep 3B > J5 > Mahlavu > SK-Hep-1, respectively. Similarly, the cytotoxicity response patterns of these HCC cells against arsenic trioxide (ATO), a ROS-producing anti-cancer drug, were exactly identical to the order of ranking instigated by the radiotherapy (RT) treatment. Next, γ‑GCSh-overexpressing GCS30 cells were found to possess excellent ability to profoundly mitigate both the drop of Δψm and apoptotic TUNEL-positive cell population engendered by ATO, cisplatin, doxorubicin, and RT treatments. Significance: Our data unequivocally demonstrate that γ‑GCSh may represent a prime target for overcoming anti-cancer drugs and RT resistance for HCC cells.

Original languageEnglish
Pages (from-to)25-31
Number of pages7
JournalLife Sciences
Volume198
DOIs
Publication statusPublished - Apr 1 2018

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Keywords

  • Chemo- and radio-resistance
  • GCS30 cells
  • Hepatocellular carcinoma
  • Intracellular glutathione (iGSH)
  • ROS-producing anti-cancer drugs
  • γ‑Glutamylcysteine synthetase heavy chain (γ‑GCSh)

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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