Expression of the zinc finger gene EVI-1 in ovarian and other cancers

Abstract

Summary The EVI-I gene was originally detected as an ectopic viral insertion site and encodes a nuclear zinc finger DNA-binding protein. Previous studies showed restricted EVI-1 RNA or protein expression during ontogeny; in a kidney and an edometrial carcinoma cell line; and in normal murine oocytes and kidney cells. EVI-1 expression was also detected in a subset of acute myeloid leukaemias (AMLs) and myelodysplasia. Because EVI-1 is expressed in the urogenital tract during development, we examined ovarian cancers and normal ovaries for EVI-1 RNA expression using reverse transcription-polymerase chain reaction (RT-PCR) and RNAase protection. Chromosome abnormalities were examined using karyotypes and whole chromosome 3 and 3q26 fluorescence in situ hybridisation (FISH). RNA from six primary ovarian tumours, five normal ovaries and 47 tumour cell lines (25 ovarian, seven melanoma, three prostate, seven breast and one each of bladder, endometrial, lung, epidermoid and histiocytic lymphoma) was studied. Five of six primary ovarian tumours, three of five normal ovaries and 22 of 25 ovarian cell lines expressed EVI-1 RNA. A variety of other non-haematological cancers also expressed EVI-1 RNA. Immunostaining of ovarian cancer cell lines revealed nuclear EVI-1 protein. In contrast, normal ovary stained primarily within oocytes and faintly in stroma. Primary ovarian tumours showed nuclear and intense, diffuse cytoplasmic staining. Quantitation of EVI-1 RNA, performed using RNAase protection, showed ovarian carcinoma cells expressed 0 to 40 times the EVI-I RNA in normal ovary, and 0 -6 times the levels in leukaemia cell lines. Southern analyses of ovarian carcinoma cell lines showed no amplification or rearrangements involving EVI-1. In some acute leukaemias, activation of EVI-1 transcription is associated with translocations involving 3q26, the site of the EVI-I gene. Ovarian carcinoma karyotypes showed one line with quadruplication 3(q24q27), but no other clonal structural rearrangements involving 3q26. However, whole chromsome 3 and 3q26 FISH performed on lines with high EVI-1 expression showed translocations involving chromosome 3q26. EVI-1 is overexpressed in ovarian cancer compared with normal ovaries, suggesting a role for EVI-1 in solid tumour carcinogenesis or progression. Mechanisms underlying EVI-1 overexpression remain unclear, but may include rearrangements involving chromosome 3q26.

Evi1 is a survival factor which conveys resistance to both TGFβ- and taxol-mediated cell death via PI3K/AKT

“…Evi1 mRNA was also abundant in HT-29 cells Figure 6b. Evi1 is located on human chromosome 3q26, and this region is known to be amplified in a number of carcinomas (Brass et al, 1996;Brooks et al, 1996;Racz et al, 1999). Therefore, we used quantitative real-time PCR to measure Evi1 gene copy number in the human colon cancer cell lines.…”

“…Evi1 is located on human chromosome 3q26, and the 3q25-27 region is amplified in cancer of the cervix (Sugita et al, 2000), ovary (Sonoda et al, 1997), lung (Brass et al, 1996;Racz et al, 1999;Imoto et al, 2001), head and neck (Bergamo et al, 2000), and prostate (Sattler et al, 2000). The relationship between 3q26 amplification and Evi1 expression has not been systematically studied, although it is known that Evi1 is overexpressed in some ovarian cancers (Brooks et al, 1996). These data suggest that Evi1 may play a role in the initiation and/or progression of solid tumors, as well as hematopoietic malignancies.…”

The EVI1 gene in myeloid leukemia

“…In addition, expression of EVI1 has been reported in ovarian and other cancers and in promyelocytic leukemia. 69,70 In addition to the t(3;12) and t(3;21), EVI1 is involved in several other chromosomal translocations such as the t(2;3)(p13;q26), t(2;3)(q23;q26), t(3;7)(q26;q22), t(3;13) (q27;q13-14), and t(3;17)(q26;q22). [71][72][73][74][75][76][77] Although these rearrangements result in EVI1 overexpression, as determined by RT-PCR of the 3Ј region of the gene, it is not known yet whether the inappropriate expression relates to EVI1 only or to a fusion protein which includes EVI1.…”

Evi-1 ZF1 DNA binding activity and a second distinct transcriptional repressor region are both required for optimal transformation of Rat1 fibroblasts

“…Primary murine (Bergeron et al, 1992) and human leukaemia cells (Morishita et al, 1992a) also have retroviral insertions or translocations, respectively, which activate Evi-1 gene expression. Several lines of evidence strongly suggest that the activation of Evi-1 expression contributes to cell transformation: (1) Some translocations produce either a truncated (Ogawa et al, 1996;Suzukawa et al, 1997) or a fusion Evi-1 protein product (Mitani et al, 1994); (2) Evi-1 is overexpressed in ovarian cancers (Brooks et al, 1996) suggesting a link with other cancers as well as leukaemia; (3) Constitutive Evi-1 expression in both primary erythroid progenitor cells and 32Dcl3 myeloid cells (Morishita et al, 1992b) results in the loss of erythropoietin responsiveness and G-CSF-dependent survival respectively; and (4) Evi-1 transforms Rat1 ®broblasts (Kurokawa et al, 1995).…”