Glycosylated DOTA−α-Melanocyte-Stimulating Hormone Analogues for Melanoma Targeting: Influence of the Site of Glycosylation on in Vivo Biodistribution

2009 ◽  
Vol 20 (5) ◽  
pp. 984-993 ◽  
Author(s):  
Jean-Philippe Bapst ◽  
Martine Calame ◽  
Heidi Tanner ◽  
Alex N. Eberle
1999 ◽  
Vol 112 (5) ◽  
pp. 623-630
Author(s):  
D. Rusciano ◽  
P. Lorenzoni ◽  
M.M. Burger

B16 murine melanoma cells selected in vivo for enhanced liver metastatic ability (B16-LS9) show on the one hand an increased expression and constitutive activation of the proto-oncogene c-met (the receptor for hepatocyte growth factor/scatter factor), and on the other hand a more differentiated phenotype, when compared to the parental cell line, B16-F1. Following this observation, we have tried to establish whether there is a direct relationship between differentiation and c-met expression in B16 melanoma cells. Treatment of these cells with differentiating agents indicated that c-met expression was strongly induced by melanocyte stimulating hormone, while retinoic acid had almost no influence. c-met induction was triggered by engagement of the melanocortin receptor, cAMP elevation and PKA/PKC(α) activation, as respectively shown by the effects of ACTH, cAMP elevating agents and specific PK inhibitors. Regulation of c-met expression via the melanocortin receptor and cAMP raises the intriguing possibility that autocrine and/or paracrine mechanisms acting in vivo on this circuit might influence (through c-met expression and activation) the metastatic behavior of these tumor cells, which we have shown to be dependent on their c-met expression.


1999 ◽  
Vol 26 (6) ◽  
pp. 687-693 ◽  
Author(s):  
JianQing Chen ◽  
Michael F. Giblin ◽  
Nannan Wang ◽  
Silvia S. Jurisson ◽  
Thomas P. Quinn

1993 ◽  
Vol 139 (2) ◽  
pp. 295-300 ◽  
Author(s):  
E. Ellerkmann ◽  
R. D. Kineman ◽  
T. E. Porter ◽  
L. S. Frawley

ABSTRACT We have previously reported that hypophysial neurointermediate lobe peptides, di-acetylated α-melanocyte-stimulating hormone (di-ac-α-MSH) and N-acetylated β-endorphin (N-ac-β-END), can acutely increase the relative number of prolactin-secreting cells in anterior pituitary cell cultures from ovariectomized rats. Inasmuch as the des-acetylated forms of these peptides (des-ac-α-MSH and β-END) were not effective in this regard, we concluded that acetylation was an absolute requirement for manifestation of the recruitment response. The aim of the present study was to determine whether these des-acetylated variants could antagonize the mammotrope-recruiting activity of their acetylated congeners. Treatment of anterior pituitary cell cultures with di-ac-α-MSH and N-ac-β-END increased the relative amount of prolactin secretors above control values. Interestingly, des-acetylated variants of α-MSH and β-END blocked the mammotrope-recruitment activity of their respective acetylated forms. In addition, β-END antagonized the mammotrope-recruitment activity of di-ac-α-MSH while des-ac-α-MSH did not attenuate the stimulatory effect of N-ac-β-END. Given that mammotropes maintained in vivo are exposed to all these peptides, it is possible that these acetylated and non-acetylated congeners may act in an opposing manner to regulate dynamic prolactin release. Journal of Endocrinology (1993) 139, 295–300


1980 ◽  
Vol 58 (3) ◽  
pp. 326-329 ◽  
Author(s):  
M. E. Celis

The effects of Leu-enkephalin, Met-enkephalin, and β-endorphin on melanocyte-stimulating hormone (MSH) secretion were studied in vivo and in vitro. The three opioid peptides release MSH. In vitro this release is dose dependent for Met-enkephalin between 10 and 1000 ng/mL and for Leu-enkephalin between 10 and 100 ng/mL. β-Endorphin releases MSH at the low concentration of 1 ng/mL and the effect is dose dependent between 1 and 100 ng/mL. Naloxone reverses this effect. In vivo the three petptides release MSH.


1983 ◽  
Vol 245 (1) ◽  
pp. E47-E54 ◽  
Author(s):  
D. Rudman ◽  
B. M. Hollins ◽  
M. H. Kutner ◽  
S. D. Moffitt ◽  
M. J. Lynn

Three types of alpha-melanocyte-stimulating hormone (alpha MSH) that differ in the acetyl status of the N-terminal serine have been found in the neurointermediate lobe of the pituitary gland and in the brain: desacetyl alpha MSH, which lacks an acetyl group; monoacetyl alpha MSH, in which the amino group of the serine is acetylated; and diacetyl alpha MSH, in which both amino and hydroxy groups of the serine are acetylated. We compared the lipolytic and melanotropic actions of these three peptides, and their rates of disappearance from plasma, both in vitro and in vivo. The following differences were found. a) For in vitro lipolytic actions on rabbit adipose tissue slices, the potencies differed according to the order diacetyl = monoacetyl greater than desacetyl. On rabbit isolated adipocytes, however, the three peptides were equipotent. b) For in vivo lipolytic action in the rabbit, not only potency but also kinetics differed. Diacetyl alpha MSH had the slowest onset, longest duration, and greatest potency. The desacetyl variant had the quickest onset, shortest duration, and least potency. c) The half-life for elimination from rabbit plasma both in vitro and in vivo was shortest for the desacetyl form and longest for the diacetyl peptide. d) For in vitro melanotropic effect on frog skin, kinetics of action were the same for all three peptides, but potency differed according to the order diacetyl = monoacetyl greater than desacetyl. Thus acetylation of alpha MSH alters lipolytic and melanotropic potencies in vitro and lipolytic potency and kinetics in vivo. These differences result in part from the fact that acetylation slows the degradation of the tridecapeptide both inside and outside the circulation.


1966 ◽  
Vol 51 (1) ◽  
pp. 149-160 ◽  
Author(s):  
Halvor Möller ◽  
Aaron B. Lerner

ABSTRACT The mechanism of aggregation induced in MSH-dispersed dermal melanocytes was studied in Rana pipiens by reflectance photometry in vitro and by microscopy in vivo. Acetylcholine inhibits MSH strongly and irreversibly in one third of all frogs tested in vitro and has almost no effect on the remaining animals. No lightening action occurs in vivo. Different skin samples from the same animal give the same response to acetylcholine. An individual response to acetylcholine implies similar responses to other cholinergics. The lightening action of acetylcholine is inhibited by atropine. Noradrenaline induces a reversible MSH-inhibition in all frogs in vitro as well as in vivo. The lightening action of noradrenaline, inhibited by sympatholytics, is ten times stronger than that of acetylcholine. The l-isomer has only twice the lightening potency as the d-isomer. Both lightening agents work if given at the maximum of MSH-dispersion or before the addition of MSH. Fundamental differences between the mechanisms of dispersion and aggregation, and between the lightening induced by acetylcholine and by noradrenaline, are emphasized.


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