HAX-1 overexpression, splicing and cellular localization in tumors.
BACKGROUND
HAX-1 has been described as a protein potentially involved in carcinogenesis and especially metastasis. Its involvement in regulation of apoptosis and cell migration along with some data indicating its overexpression in cancer cell lines and tumors suggests that HAX-1 may play a role in neoplastic transformation. Here we present the first systematic analysis of HAX-1 expression in several solid tumors.


METHODS
Using quantitative RT-PCR, we have determined the mRNA levels of HAX1 splice variant I in several solid tumors. We have also analyzed by semiquantitative and quantitative RT-PCR the expression of five HAX-1 splice variants in breast cancer samples and in normal tissue from the same individuals. Quantitative PCR was also employed to analyze the effect of estrogen on HAX1 expression in breast cancer cell line. Immunohistochemical analysis of HAX-1 was performed on normal and breast cancer samples.


RESULTS
The results reveal statistically important HAX1 up-regulation in breast cancer, lung cancer and melanoma, along with some minor variations in the splicing pattern. HAX-1 up-regulation in breast cancer samples was confirmed by immunohistochemical analysis, which also revealed an intriguing HAX-1 localization in the nuclei of the tumor cells, associated with strong ER status.


CONCLUSIONS
HAX-1 elevated levels in cancer tissues point to its involvement in neoplastic transformation, especially in breast cancer. The connection between HAX-1 nuclear location and ER status in breast cancer samples remains to be clarified.
Trebinska
Alicja
A
Cancer Center Institute, Roentgena 5, 02-781 Warsaw, Poland.
Rembiszewska
Alina
A
Ciosek
Karolina
K
Ptaszynski
Konrad
K
Rowinski
Sebastian
S
Kupryjanczyk
Jolanta
J
Siedlecki
Janusz A
JA
Grzybowska
Ewa A
EA
D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis* / Q000737:chemistry*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement; D002467:Cell Nucleus / Q000378:metabolism; D002471:Cell Transformation, Neoplastic; D047628:Estrogen Receptor alpha / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008875:Middle Aged; D012326:RNA Splicing
D048868:Adaptor Proteins, Signal Transducing; D047628:Estrogen Receptor alpha; C104759:HAX1 protein, human