10th International Congress "Cell Volume Regulation: Novel Therapeutic Targets and Pharmacological Approaches"
ACID-EXTRUDING TRANSPORTERS IN MAMMARY AND PANCREATIC ADENOCARCINOMA: REGULATION AND ROLES IN CELL MOTILITY
Pedersen, S.F.
Department of Biology, University of Copenhagen, Copenhagen, Denmark
A fundamental property of solid tumors is an altered pH-profile compared to normal tissues. This at least in part reflects increased glycolytic metabolism, necessitating increased acid extrusion to maintain survival, and in turn stimulating cancer cell motility [1, 2]. Acid extruding transporters are therefore interesting potential targets in cancer. The overall aim of these studies was to explore the regulation and roles of acid extruding transporters in human mammary and pancreatic adenocarcinomas.
In MCF-7 mammary cancer cells, expression of a constitutively active ErbB2 receptor (ANErbB2) greatly increased pH regulatory capacity, mediated by the Na+/H+ exchanger NHE1 and the Na+, HCO3-cotransporter NBCnl [3]. ANErbB2 expression or stimulation of wt ErbB receptors greatly increased NBCn1 expression and induced NHE1 phosphorylation at Ser703 [3, 4]. NHE1 was strongly expressed in invadopodial rosettes and, surprisingly, negatively regulated adhesion and 2D motility of ANErbB2-MCF-7 cells [5]. Finally, NHE1 and NBCn1 were upregulated in primary carcinomas and lymph node metastases of mammary cancer patients and Na+,HCO3- cotransport was a major determinant of pHt regulation in freshly dissected human mammary tumors.
In PDAC, we screened a panel of 4 human PDAC cell lines (AsPC-1, BxPC-3, Panc-1, MIAPaCa-2) against normal human pancreatic ductal cells (HPDE) by qPCR, immunoblotting and immunocytochemistry, and found major changes in the expression of NHE1, -2, V-type H+-ATPase subunit a3, Na+-HCO3- transporters SLC4A7 and -A8, anion exchangers SLC4A2 and -3, and H+/lactate cotransporters MCT1 and -4.
In conclusion, expression and regulation of NHE1 and NBCn1 are markedly altered in breast cancer, resulting in altered pH regulation and cell motility. Also PDAC cells exhibit major changes in the expression pattern of acid extruding transporters. Ongoing experiments are addressing the functional relevance of this in PDAC development.
References
1. Boedtkjer, E., Bunch, L., Pedersen, S.F. Curr. Pharm. Des., 2012, 18, pp. 1345-1371.
2. Webb, B.A., Chimenti, M., Jacobson, M.P., Barber, D.L. Nat. Rev. Cancer., 2011, 11, pp. 671-677.
3. Lauritzen, G., Jensen, M.B., Boedtkjer, E., Dybboe, R., Aalkjaer, C., Nylandsted, J., Pedersen, S.F. Exp. Cell Res., 2010), 316, pp. 2538-2553.
4. Lauritzen, G., Stock, C.M., Lemaire, J., Lund, S.F., Jensen, M.F., Damsgaard, B., Petersen, K.S., Wiwel, M., Ronnov-Jessen, L., Schwab, A., Pedersen, S.F. Cancer Lett., 2012, 317, pp. 172-183.
Бюллетень сибирской медицины, 2013, том 12, № 4, с. 24-68
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