Am J Cancer Res 2013;3(3):278-289
Original Article
The C-terminal common to group 3 POTES (CtG3P): a newly discov-ered
nucleolar marker associated with malignant progression and metastasis
Samantha M Redfield, Jinghe Mao, He Zhu, Zhi He, Xu Zhang, Steven A Bigler, Xinchun Zhou
Department of Pathology, University of Mississippi Medical Center, 2500 North State Street, MS 39216, USA; Department of
Biology, Touga-loo College, 500 West County Line Road, Tougaloo, MS 39157, USA; Center of biostatistics and Bioinformatics,
University of Mississippi Medical Center, 2500 North State Street, MS 39216, USA; Department of Pathology, Mississippi Baptist
Medical Center, 1190 North State Street, Jackson, MS 39202, USA
Received May 10, 2013; Accepted May 31, 2013; Epub June 20, 2013; Published June 30, 2013
Abstract: A gene family expressed in prostate, ovary, testis and placenta (POTEs) is newly defined and primate-specific. POTE
genes have 13 paralogs, which are dispersed in 8 chromosomes and divided into three groups. The proteins encoded by these
genes contain three domains: An N-terminal, ankyrin repeats and a C-terminus. Previous studies suggest that POTE proteins
are localized in the inner aspect of cellular membrane and are considered as cancer-testis antigens, because they expressed
widely in cancers, but in limited benign tissues. In this study, we will study the subcellular distribution of all POTE proteins and
their associations with the progress and metastasis of malignancies. By performing Immunohistochemistry,
Immunocytochemistry and immunofluorescence assay on tissue microarray slides containing tissues with different pathology
and origins or on cell lines, we found that the epitopes of N- and C-terminals of all detected POTEs were widely expressed in
benign and malignant tissues. Among these epitopes, C-terminal common to group 3 POTEs (CtG3P) was the only portion
localized in nucleoli. The nucleolar IHC scores for CtG3P was lowest in benign tissues (4.47 ± 3.43), significantly higher in
localized malignancies (5.32 ± 3.36, p = 3.63E-02), and highest in metastatic malignancies (7.90 ± 2.29, p = 8.13E-12). The
CtG3P was better in differentiation of benign from malignant changes, and/or in differentiation of localized from metastatic
cancers as compared with Ki-67 and AgNORs. In addition, transient transfection of siRNA against mRNA of group 3 POTEs
influences the growth and survival of MCF-7 cells in vitro in a dose dependent manner. (ajcr0000201).
Keywords: POTEs gene family, prostate, ovary, testis and placenta, cancer, ankyrin repeats, cancer-testis antigens, nucleolar
marker, malig-nant progression, metastasis
Address correspondence to: Dr. Xinchun Zhou, Department of Pathology, University of Mississippi Medical Center, 2500 North
State Street, Jackson, MS 39216, USA. Phone: 601-984-1687; Fax: 601-984-1531; E-mail: XZhou@umc.edu
Original Article
The C-terminal common to group 3 POTES (CtG3P): a newly discov-ered
nucleolar marker associated with malignant progression and metastasis
Samantha M Redfield, Jinghe Mao, He Zhu, Zhi He, Xu Zhang, Steven A Bigler, Xinchun Zhou
Department of Pathology, University of Mississippi Medical Center, 2500 North State Street, MS 39216, USA; Department of
Biology, Touga-loo College, 500 West County Line Road, Tougaloo, MS 39157, USA; Center of biostatistics and Bioinformatics,
University of Mississippi Medical Center, 2500 North State Street, MS 39216, USA; Department of Pathology, Mississippi Baptist
Medical Center, 1190 North State Street, Jackson, MS 39202, USA
Received May 10, 2013; Accepted May 31, 2013; Epub June 20, 2013; Published June 30, 2013
Abstract: A gene family expressed in prostate, ovary, testis and placenta (POTEs) is newly defined and primate-specific. POTE
genes have 13 paralogs, which are dispersed in 8 chromosomes and divided into three groups. The proteins encoded by these
genes contain three domains: An N-terminal, ankyrin repeats and a C-terminus. Previous studies suggest that POTE proteins
are localized in the inner aspect of cellular membrane and are considered as cancer-testis antigens, because they expressed
widely in cancers, but in limited benign tissues. In this study, we will study the subcellular distribution of all POTE proteins and
their associations with the progress and metastasis of malignancies. By performing Immunohistochemistry,
Immunocytochemistry and immunofluorescence assay on tissue microarray slides containing tissues with different pathology
and origins or on cell lines, we found that the epitopes of N- and C-terminals of all detected POTEs were widely expressed in
benign and malignant tissues. Among these epitopes, C-terminal common to group 3 POTEs (CtG3P) was the only portion
localized in nucleoli. The nucleolar IHC scores for CtG3P was lowest in benign tissues (4.47 ± 3.43), significantly higher in
localized malignancies (5.32 ± 3.36, p = 3.63E-02), and highest in metastatic malignancies (7.90 ± 2.29, p = 8.13E-12). The
CtG3P was better in differentiation of benign from malignant changes, and/or in differentiation of localized from metastatic
cancers as compared with Ki-67 and AgNORs. In addition, transient transfection of siRNA against mRNA of group 3 POTEs
influences the growth and survival of MCF-7 cells in vitro in a dose dependent manner. (ajcr0000201).
Keywords: POTEs gene family, prostate, ovary, testis and placenta, cancer, ankyrin repeats, cancer-testis antigens, nucleolar
marker, malig-nant progression, metastasis
Address correspondence to: Dr. Xinchun Zhou, Department of Pathology, University of Mississippi Medical Center, 2500 North
State Street, Jackson, MS 39216, USA. Phone: 601-984-1687; Fax: 601-984-1531; E-mail: XZhou@umc.edu
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American Journal of Cancer Research
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