Mammalian selenoprotein differentially expressed in tumor cells

Abstract

A 15 kDa selenium-containing protein (“selenoprotein”) is disclosed. The protein is shown to be differentially expressed in cancer cells, such as prostate cancer cells. There is a correlation between the presence of a polymorphism at nucleotide positions 811 and 1125 of the 15 kDa selenoprotein gene, and the presence of cancer. This polymorphism is more prevalent in the African American population. The determination of an individual's genotype may be used as an indicator of the need for dietary selenium supplementation to inhibit tumor development. Compositions including the isolated protein, specific binding agents that recognize the protein, as well as underlying nucleic acid sequences are presented, as are methods of using such compositions.

1 . A method of detecting a polymorphism in a human 15 kDa selenoprotein gene, comprising determining all or part of a nucleic acid sequence of the human 15 kDa selenoprotein gene, cDNA or mRNA in a biological sample. 
     
     
         2 . The method of  claim 1 , wherein the polymorphism is C811. 
     
     
         3 . The method of  claim 1 , wherein the polymorphism is G1125. 
     
     
         4 . The method of  claim 1 , wherein the polymorphism is C811/G1125. 
     
     
         5 . The method of  claim 1 , further comprising hybridizing the biological sample with a nucleic acid probe under conditions whereby the probe will hybridize to the 15 kDa selenoprotein gene, cDNA or mRNA carrying a polymorphism selected from the group consisting of C811, G1125 and C811/G1125, but not to a wild-type 15 kDa selenoprotein gene, cDNA or mRNA. 
     
     
         6 . The method of  claim 1 , wherein the nucleic acid sequence of the human 15 kDa selenoprotein gene has at least 90% sequence identity to SEQ ID NO: 2 or SEQ ID NO: 3 
     
     
         7 . The method of  claim 1 , wherein the nucleic acid sequence of the human 15 kDa selenoprotein gene has at least 95% sequence identity to SEQ ID NO: 2 or SEQ ID NO: 3. 
     
     
         8 . The method of  claim 1 , wherein the human 15 kDa selenoprotein gene comprises the nucleic acid sequence shown in SEQ ID NO: 2 or SEQ ID NO: 3. 
     
     
         9 . The method of  claim 1 , wherein the nucleic acid sequence encodes a peptide comprising the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 4. 
     
     
         10 . The method of  claim 1 , wherein detecting a polymorphism in a human 15 kDa selenoprotein gene is used to determine if a human has an increased risk of developing cancer. 
     
     
         11 . The method of  claim 10 , wherein the cancer is selected from the group consisting of prostate cancer, liver cancer, head and neck cancers, and colon cancer.