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

TY - JOUR

T1 - Molecular mechanisms of toxicity and cell damage by chemicals in a human pancreatic beta cell line, 1.1B4

AU - Vasu, Srividya

AU - McClenaghan, Neville

AU - Flatt, Peter

PY - 2013/10/1

Y1 - 2013/10/1

N2 - 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

AB - 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

KW - 1.1B4 cells

KW - apoptosis

KW - beta cells

KW - chemicals

KW - oxidative stress

KW - toxicity

U2 - 10.1097/MPA.0000000000000645

DO - 10.1097/MPA.0000000000000645

M3 - Article

VL - 45

SP - 1320

EP - 1329

JO - Pancreas

T2 - Pancreas

JF - Pancreas

SN - 0885-3177

IS - 9

ER -