Pituitary adenylate cyclase-activating polypeptide attenuates streptozotocin-induced apoptotic death of RIN-m5F cells through regulation of Bcl-2 family protein mRNA expression

FEBS J. 2008 Nov;275(22):5542-51. doi: 10.1111/j.1742-4658.2008.06672.x.


Oxidative stress, followed by the apoptotic death of pancreatic beta cells, is considered to be one of causative agents in the evolution of the type 2 diabetic state; therefore, the protection of beta cells can comprise an efficacious strategy for preventing type 2 diabetes. In the present study, RIN-m5F cells (i.e. the rat insulinoma beta cell line) were stimulated with streptozotocin, resulting in a time- and concentration-dependent release of lactate dehydrogenase. There appeared to be significant apoptotic cell death after 2 h of treatment with streptozotocin at 10 mM, as demonstrated by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling staining and 2.6-fold activation of cellular caspase-3, an apoptotic enzyme. By contrast, some neuropeptides of the glucagon-secretin family and coenzyme Q(10), an endogenous mitochondrial antioxidant, could attenuate streptozotocin cytotoxicity, and especially pituitary adenylate cyclase-activating polypeptide (PACAP), at a concentration of 10(-7) M, exhibited 34% attenuation of lactate dehydrogenase release from streptozotocin-treated RIN-m5F cells. Quantitative RT-PCR experiments indicated the inhibitory effect of PACAP on streptozotocin-evoked up-regulation of pro-apoptotic factor (Noxa and Bax) and a 2.3-fold enhancement of Bcl-2 mRNA expression, a pro-survival protein, was also observed after addition of PACAP. The data obtained suggest the anti-apoptotic role of PACAP in streptozotocin-treated RIN-m5F cells through the regulation of pro-apoptotic and pro-survival factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Apoptosis Regulatory Proteins / genetics
  • Cell Line, Tumor
  • Insulin-Secreting Cells / pathology*
  • L-Lactate Dehydrogenase / metabolism
  • Neuropeptides / pharmacology
  • Pituitary Adenylate Cyclase-Activating Polypeptide / pharmacology*
  • Proto-Oncogene Proteins c-bcl-2 / genetics*
  • RNA, Messenger / drug effects
  • Rats
  • Streptozocin / pharmacology*
  • Ubiquinone / analogs & derivatives
  • Ubiquinone / pharmacology
  • Up-Regulation / genetics
  • bcl-2-Associated X Protein / genetics


  • Apoptosis Regulatory Proteins
  • Neuropeptides
  • Pituitary Adenylate Cyclase-Activating Polypeptide
  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Messenger
  • bcl-2-Associated X Protein
  • Ubiquinone
  • Streptozocin
  • L-Lactate Dehydrogenase
  • coenzyme Q10