Molecular mechanisms of toxicity and cell damage by chemicals in a human pancreatic beta cell line, 1.1B4

Srividya Vasu, Neville McClenaghan, Peter Flatt

Research output: Contribution to journalArticle

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Abstract

Objectives: Mechanisms of toxicity and cell damage were investigated in novel clonal human pancreatic beta cell line, 1.1B4, after exposure to streptozotocin, alloxan, ninhydrin, and hydrogen peroxide. Methods: Viability, DNA damage, insulin secretion/content, [Ca2+]i, andglucokinase/hexokinase, mRNA expression were measured by MTTassay, comet assay, radioimmunoassay, fluorometric imaging plate reader, enzymecoupled photometry, and real-time polymerase chain reaction, respectively. Results: Chemicals significantly reduced 1.1B4 cell viability in a time/concentration–dependent manner. Chronic 18-hour exposure decreased cellularinsulin, glucokinase, and hexokinase activities. Chemicals decreased transcription of INS, GCK, PCSK1, PCSK2, and GJA1 (involved in secretory function). Insulin release and [Ca2+]i responses to nutrients and membrane-depolarizing agents were impaired. Streptozotocin and alloxanup-regulated transcription of genes, SOD1 and SOD2 (antioxidant enzymes). Ninhydrin and hydrogen peroxide up-regulated SOD2 transcription, whereas alloxan and hydrogen peroxide increased CAT transcription. Chemicals induced DNA damage, apoptosis, and increasedcaspase 3/7 activity. Streptozotocin and alloxan decreased transcription of BCL2 while increasing transcription of BAX. Chemicals did not affect transcription of HSPA4 and HSPA5 and nitrite production. Conclusions: 1.1B4 cells represent a useful model of human beta cells. Chemicals impaired 1.1B4 cell secretory function and activated antioxidant defense and apoptotic pathways without
Original languageEnglish
Pages (from-to)1320-1329
JournalPancreas
Volume45
Issue number9
DOIs
Publication statusPublished - 1 Oct 2013

Keywords

  • 1.1B4 cells
  • apoptosis
  • beta cells
  • chemicals
  • oxidative stress
  • toxicity

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