Molecular cloning, characterization and isolation of novel spliced variants of the human ortholog of a rat estrogen-regulated membrane-associated protein, UO-44

Abstract

We have previously reported the characterization of an estrogen-regulated rat uterine-ovarian-specific complementary DNA (UO-44). To understand the involvement of this protein in the initiation and progression of human ovarian and uterine cancers, we now report the cloning and characterization of the human ortholog (HuUO-44). HuUO-44 is mapped to chromosome 10q26.13 and contains nine exons. Multiple tissue Northern blot detected two HuUO-44 transcripts of approximately 2 and 3 kb in the pancreas. RT-PCR demonstrated that HuUO-44 undergoes a complex series of alternative splicing events between exons 2 and 6 that yielded four novel splice variants, HuUO-44A, HuUO-44B, HuUO-44C and HuUO-44D. Putative functional motifs identified in HuUO-44 are two CUB domains and a zona-pellucida domain. Transfection studies demonstrated the membrane-associated nature of HuUO-44. By immunohistochemistry, HuUO-44 was located to the normal ovarian and ovarian tumor epithelial cells; in NIH-OVCAR3 ovarian cancer cells, HuUO-44 was detected only at the leading edge of the dividing cells. Most importantly, a marked loss in cell attachment and proliferation was observed in NIH-OVCAR3 cells cultured in the presence of a polyclonal HuUO-44 antiserum. These findings suggest the potential role of HuUO-44 in cell motility, cell-cell interactions and/or interactions with the extracellular matrices.

Crohn’s disease specific pancreatic antibodies: clinical and pathophysiological challenges

“…CUZD1, also known as UO-44, is expressed in cancerous ovarian tissue and is considered a novel serological biomarker for ovarian cancer [48]. However, Northern blot analysis revealed two differing human pancreatic UO-44 transcripts [49,50]. To the best of our knowledge, corresponding data regarding CUZD1 expression in the intestine are still lacking [17,51].…”

Silencing expression of UO-44 (CUZD1) using small interfering RNA sensitizes human ovarian cancer cells to cisplatin in vitro

“…More specifically, the human orthologue of UO-44 (HuUO-44) is involved in ovarian cancer cell attachment and proliferation (Leong et al, 2004). Collectively, these previous findings identify that UO-44 functions in ovarian cancer cell invasiveness, and silencing of UO-44 may enhance cell death following treatment with chemotherapeutic agents.…”

“…Our present study investigates the involvement of HuUO-44 in chemoresistance. UO-44 is an inscrutable protein that is overexpressed in the pancreas, uterus and ovaries (Huynh et al, 2001;Leong et al, 2004). Despite previous in vitro and in vivo studies, which reflect its multifunctionality, its common function remains unclear.…”

“…UO-44 has been implicated in diverse physiological functions, including pregnancy development (Kasik, 1998;Chen et al, 1999), protection against severity of pancreatitis (Imamura et al, 2002) and cell adhesion (Huynh et al, 2001). In our previous study, we have isolated alternatively spliced variants of the human UO-44 gene, which may function to regulate its gene expression (Leong et al, 2004). Another feature of UO-44 is its overexpression in a majority of ovarian tumors, suggesting that the gene exerts a significant role in tumorigenesis and progression of ovarian cancers (Leong et al, 2004).…”

“…In our previous study, we have isolated alternatively spliced variants of the human UO-44 gene, which may function to regulate its gene expression (Leong et al, 2004). Another feature of UO-44 is its overexpression in a majority of ovarian tumors, suggesting that the gene exerts a significant role in tumorigenesis and progression of ovarian cancers (Leong et al, 2004).…”