Naslov
NM23/NDPK Subunits in Head and Neck Tumor Cells : Where do they go?

Autori
Herak Bosnar, Maja ; de Gunzburg, J. ; Bago, Ružica ; Brečević, Lukrecija ; Weber, Igor ; Pavelić, Jasminka

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Proceedings of Abstracts of the 12th World Congress on Advances in Oncology and 10th International Symposium of Molecular Medicine and Cancer Chemoprevention Symposium ; u: International Journal of Molecular Medicine. Supplement 20 (2007) (S) / Spandidos, D.A. - Heraklion, 2007, S44-S44

Skup
12th World Congress on Advances in Oncology and 10th International Symposium on Molecular Medicine and Cancer Chemoprevention Symposium

Mjesto i datum
Hersonissos, Grčka, 11.10.2007. - 13.10.2007

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
nm23; GFP; oral squamous cell carcinoma; subcellular localization

Sažetak
Since the day of its discovery Nm23/NDPK has been assigned a number of different functions in the cell apart from its well-known ability to catalyze the conversion of (d)NDPs to (d)NTPs through a high-energy His118 intermediate. Eukaryotic NDP kinases have been reported to be catalytically active only as homo- or heterohexamers. In humans the hexamers consist of two highly homologous subunits Nm23-H1/NDPK A and Nm23-H2/NDPK B, having an 88% amino acid sequence identity. On the basis of its reduced expression in melanoma cell lines with low versus high metastatic potential nm23-H1 was proposed to constitute a potential metastatic suppressor gene. Apart from being involved in metastasis formation, Nm23 proteins have been linked to several biological processes. Although forming a functional enzyme together, Nm23-H1 and Nm23-H2 have also been assigned separate cellular functions. The aim of this study was to determine the specific, and potentially distinct, localizations of both subunits in tumor cells of different origin and differentiation and therefore to search for a possible link between their localization and the stage of disease. The issue was addressed using GFP reporter system to analyze the ectopic expression of GFP-Nm23 proteins in head and neck tumor cell lines by fluorescent microscopy techniques. Our experiments revealed that GFP-fused Nm23 proteins display the same localization in transfected cells, regardless of their origin and differentiation status. Nm23 proteins colocalize, also, with the endoplasmic reticulum, and could be found in the portion of the nuclei which appears to be cell-cycle dependent. In conclusion it seams that although Nm23-H1 and Nm23-H2 proteins have some distinct functions in the cell they perform them in the same or similar locations. The functional significance of the ER and cell cycle-dependent nuclear localization for Nm23 proteins remains to be elucidated.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

POVEZANOST RADA