Rhodamine B accumulation and MXR protein expression in mussel blood cells:effects of exposure to vincristine

Abstract

ABSTRACT. Mussel hemocytes accumulate rhodamine B within their lysosomal compartment. This intracellular retention, detected and quantified by computerised confocal microscopy, is enhanced by the presence of verapamil. Study of 2 different populations showed alteration in rhodamine B retention and simultaneous differential expression levels of proteins immunorelated to the multidrug resistance (MDR) transporter in relation to their environment. Chronic exposure of animals to the Vinca antitumor alkaloid vincristine causes the hemocytes to accumulate less rhodamine B, to be more sensitive to verapamil and to express more MDR-related proteins. These data add consistency to prevlous results on multixenobiotic resistance in mussels.

Multixenobiotic resistance protein expression in Mytilus edulis, M. galloprovincialis and Crassostrea gigas from the French coasts

“…Bivalve cells are able to bind and transport anticancer compounds against which mammalian cells are resistant , Minier & Moore 1996. It has been proposed that these molluscan Pgp could be part of a defence system against toxic compounds including anthropogenic wastes (Smital et al 2004).…”

Multixenobiotic resistance in coelomocytes from three echinoderm species

“…The presence of MXR proteins has already been reported in various invertebrates, including the sponge Suberites domuncula (W. , the marine worm Urechis caupo (Holland Toomey & Epel 1993), as well as in the haemocytes of freshwater (Zaja et al 2006) and marine mussels (Minier & Moore 1996, Marin et al 2004. Even though there are several studies available on invertebrate MXR, only 1 study discussed MXR activity in an echinoderm.…”

“…The molecular weights of Pgp and MRP are quite similar and change with species. For instance, a 135 kDa Pgp was reported in Corbicula fluminea gills (Waldmann et al 1995), while a 170 kDa Pgp was reported in Mytilus edulis and M. californianus gills (Cornwall et al 1995, Minier & Moore 1996 and a 145 and a 220 kDa Pgp were found in M. galloprovincialis (Galgani et al 1996), all determined by Western blot with the C219 anti body. Finally, other MRPs, with other molecular weights, were recognized by C9, although this is an antibody against MRP1, a 190 kDa protein (Cole et al 1992).…”

“…Since some substrates and inhibitors are more specific to one MXR protein than to another, it is sometimes possible to discriminate the proteins involved. For example, Rhodamine B (RB) is often used as a Pgp substrate (Minier & Moore 1996, Reungpatthanaphong et al 2003, Zaja et al 2006) and a similar molecule, Rhodamine 123, is used as a Pgp-and MRP-like substrate (Hollo et al 1996, Daoud et al 2000. Calcein-AM (CAM) is also known as a substrate for both Pgp-like and MRP-like proteins, but calcein, its fluorescent hydrolysis product, is only a substrate for MRP-like transporters (Hollo et al 1996, Essodaïgui et al 1998.…”

“…Indeed, the coelomocytes showed MXR activity, as indicated by the effect of MXR inhibitors on the accumulation of model MXR substrates (measured by FCM). In addition, Western blot enabled the detection of potential MXR proteins using anti-MXR antibodies, even though the identity of the proteins could not be confirmed.The presence of MXR proteins has already been reported in various invertebrates, including the sponge Suberites domuncula (W. , the marine worm Urechis caupo (Holland Toomey & Epel 1993), as well as in the haemocytes of freshwater (Zaja et al 2006) and marine mussels (Minier & Moore 1996, Marin et al 2004. Even though there are several studies available on invertebrate MXR, only 1 study discussed MXR activity in an echinoderm.…”