Insulinoma cells

Step 1 Cytotoxicity. Each polymer was evaluated, at least twice, in blind experiments, according to their toxicity toward insulinoma cells. For many polymers alternative suppliers and molecular weights were also tested. In total 37 polyanions were obtained of which 23 were systematically evaluated. By comparison, 29 of the 36 polycations procured were systematically tested. The results of these experiments are provided in Table 4. 

From Table 4 it is evident that several natural and modified polyanions did not induce insulinoma cell detachment. Furthermore, the DNA content, a quantitative metric of cell viability, was in general near the baseline (100%) observed in the control studies with PBS. In generalboth the cell attachment and DNA indices gave similar indications of cytotoxicity. Therefore, in an effort to unify these measures the third column of Table 4 reports an overall ranking of the polymer... 

The poor response of the synthetic polymers in the cytotoxicity tests with insulinoma cells (Table 4) provides further support for the utilization of polyanions as the inner cell suspending fluids. Given the rigid nature of the moderate molecular weight anionic polysaccharides, it seems reasonable that low molecular weight polycations can be effective in membrane formation, due to their high diffusivity. This will be elaborated upon in the discussion. 

Synthetic polymers are generally cytotoxic to insulinoma cells. 

Laychock, S. G., Modica, M. E., and Cavanaugh, C. T. (1991). L-arginine stimulates cyclic guanosine 3, 5 -monophosphate formation in rat islets of Langerhans and RlNm5F insulinoma cells Evidence for L-arginine Nitric oxide synthase. Endocrinology (Baltimore) 129, 3043-3052. 

Verspohl, E. J., Kuhn, M., and Ammon, H. P. T. (1988). RlNm5F (Rat insulinoma) cells possess receptors for atrial natriuretic peptide (ANP) and a functioning cGMP system Harm. Metab. Res. 20, 770-771. 

Hohmeier, H.E., Thigpen, A., Tran, V. V., Davis, R. andNewgard, C.B. (1998) Stable expression of manganese superoxide dismutase (MnSOD) in insulinoma cells prevents IL-1 beta-induced cytotoxicity and reduces nitric oxide production. J. Clin. Invest., 101, 1811-1820. 

Howard BD, Gundersen CBJ (1980) Effects and mechanisms of polypeptide neurotoxins that act presynaptically. Annu Rev Pharmacol Toxicol 20 307-36 Huang X, Wheeler MB, Kang YH, Sheu L, Lukacs GL et al. (1998) Truncated SNAP-25 (1-197), like botulinum neurotoxin A, can inhibit insulin secretion from HIT-T15 insulinoma cells. Mol Endocrinol 12 1060-70... 

Cell death, apopto- MnSOD in NOD mice (J. in IFN-y and j in TGF-/J at the transplant site) Insulinoma cells Protection against IL-1 ji Hohmeier et al. (1998)... 

Glutathion peroxi- Insulinoma cells Protection from NO and O toxicity Insulinoma cells Protection against cytokine-mediated injury Insulinoma cells Protection from NO and Tiedge et al. (1999) Lortz et al. (2000) Tiedge et al. (1999)... 

Insulinoma cells Protection against cytokine-mediated injury... 

Briscoe, C. P., Hanif, S., Arch, J. R., and Tadayyon, M. 2001. Fatty acids inhibit leptin signalling in BRIN-BD11 insulinoma cells. J. Mol. Endocrinol. 26 145-154. 

Leech, C.A., and Habener, J.F. 1997. Insulinotropic glucagon-like peptide-1-mediated activation of non-selective cation currents in insulinoma cells is mimicked by maitotoxin. J Biol Chem 212, 17987-17993. 

Fig. 1. Pertussis toxin-mediated ADP ribosylation of membrane G proteins. Isolated cell membranes (50 ng of protein) from N1E 115 cells (mouse neuroblastoma cell line), N2A cells (mouse neuroblastoma cell line), S49-1 eye cells (S49(-) mutated mouse lymphoma cell line deficient in Ga ), 549 wt cells (wild-type mouse lymphoma cell line), RBL (RBL 2H3 rat basophilic leukemia cell line), GH3 cells (GH3 rat hypophyseal tumor cell line), PC-12 (rat pheochromocytoma cell line), HIT-T15 cells (hamster insulinoma cell line), Y-1 cells (mouse adrenal cortex tumor cell line), 108 cc 15 cells (mouse/rat neuroblastoma x glioma hybrid cell line), HL-60 cells (DMSO-differentiated human leukemia cell line), HL-60 (+PT) cells (HL-60 cells pretreated with 25 ng/ml of pertussis toxin for 24 h prior to preparation of membranes), RINm5F cells (rat insulinoma cell line), and C6-2 cells (rat glioma cell line) were subjected to P-ADP-ribosylation as described in section 4.3.3. Samples were precipitated as outlined in section 4.3.5 and subjected to SDS-PAGE with separating gels containing 8% acrylamide (w/v). An autoradiogram of the dried gel is shown. Molecular masses of marker proteins are indicated (kDa). Modified Ga proteins migrate at approximately 40 kDa. Radioactivity running in front of the 30 kDa marker protein comigrates with the dye front...

Boyd RS, Duggan MJ, Shone CC, Foster KA (1995 b) The effect of botulinum neurotoxins on the release of insulin from insulinoma cell lines HIT-15 and RINm5F. In J. Biol. Chem. 270 18216-8... 

Roosterman D, Roth A, Kreienkamp H-J, Richter D, Meyerhof W (1997) Distinct agonist-mediated endocytosis of cloned rat somatostatin receptor subtypes expressed in insulinoma cells. J Neuroendocrinol 9 741-751... 

Corkey, B.E., K. Tomheim, J.T. Deeney, M.C. Glennon, J.C. Parker, F.M. Matschinsky, N.B. Ruderman M. Prentki. 1988. Linked oscillations of free Ca and the ATP/ADP ratio in permeabilized RINmSF insulinoma cells supplemented with a glycolyzing cell-free muscle extract. J. Biol. Chem. 263 4254-8. 

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