Einfluss der löslichen Guanylylzyklase auf die Expression der cGMP-Exporter MRP4 und 5 in humanen Melanomzellen unter Hypergravitationsbedingungen

  • Influence of the soluble guanylyl cyclase on the expression of the cGMP exporter MRP4 and 5 in human melanoma cells under hypergravity conditions

Tsiockas, Wasiliki; Gerzer, Rupert (Thesis advisor); Conrath, Uwe (Thesis advisor)

Aachen : Publikationsserver der RWTH Aachen University (2012)
Dissertation / PhD Thesis

Aachen, Techn. Hochsch., Diss., 2012


Previous studies showed that altered gravity conditions lead to different adaptation responses in various cells, like changes in proliferation, morphology or signal transduction. These changes are forwarded through intracelllular signaling cascades which are, amongst others, mediated by the important second messengers cGMP and cAMP. On the basis of their strategical position in the epidermis, human melanocytes are constantly exposed to mechanical stimuli. That makes them an interesting in vitro system for hyper- and hypogravity studies. Earlier studies showed different influences of hypergravity on the cGMP- and cAMP-Efflux and the expression of the highly-selective nucleotide transporters MRP (multidrug resistance proteins) 4/5 in human melanocytes and melanoma cells with different metastatic behaviour. Based on these results the influence of the soluble, NO-sensitive guanylylcyclase (sGC) on the hypergravity-induced expression of MRP4/5, endothelial and inducible nitric oxide synthase (e/iNOS) and particulate GC (GC-A/B) in the non-metastatic 1F6 melanoma cell line was studied by silencing the mRNA-expression of the sGCb1 subunit through siRNA-transfection. The data show an increased expression of the investigated genes (MRP4/5, e/iNOS) after the cells were exposed to hypergravity (5g for 24 h), whereas no alteration could be found after silencing the sGCb1 subunit with siRNA. Furthermore the expression of the investigated genes remained unaffected in highly metastatic BLM cells which, as siRNA-sGCb1 transfected 1F6 melanoma cells, do not have an NO-sensitive sGC. The received data indicate an important role of sGC on the adaptation of non-metastatic 1F6 melanoma cells, but not highly metastatic BLM cells, to hypergravity. The current and further studies could contribute to the question whether astronauts have an increased risc to develop cancer and how to improve medical care during long-term space flights.