Monoclonal antibody to prostate cancer nuclear matrix protein (PRO:4-216) recognizes nucleophosmin/B23

Abstract

BACKGROUND The nuclear protein B23, nucleophosmin, is an RNA‐associated nucleolar phosphoprotein reported to be more abundant in malignant and growing cells than in normal nondividing cells. We examined the levels of B23 in fresh human prostate tissue and in five human prostate cancer cell lines with monoclonal antibodies (mAb) to nucleophosmin (α‐B23) and to human prostate cancer nuclear matrix proteins (PRO:4‐216). METHODS mAb PRO:4‐216 and mAb α‐B23 were used for protein level detection. Nuclear matrix proteins (NMPs) were prepared from prostate tumor and five human prostate cancer cell lines: LNCaP, TSU, DU145, PC‐3, and PPC‐1. The NMPs were run on one‐dimensional and two‐dimensional (2D) electrophoresis gels for Western blot analysis with the two mAbs. Histologic sections from paraffin‐embedded normal and cancerous prostate tissue were stained immunohistochemically with both mAbs. RESULTS PRO:4‐216 and B23 mAbs identified a 40‐kD protein (pI ∼5.0) by Western blot analysis in the human prostate cancer cell lines and on two‐dimensional blots of human prostate cancer NMPs. Immunohistochemical staining demonstrated large punctate nuclear dots in most cancer nuclei, while staining of normal tissue was less intense or absent. Predominant reactivity was of epithelial nuclei, with some minor reactivity of stromal nuclei. Red blood cells (RBCs) and white blood cells (WBCs) were routinely negative. CONCLUSIONS PRO:4‐216, previously characterized as recognizing prostate cancer nuclear matrix proteins, recognized B23/nucleophosmin. PRO:4‐216 and α‐B23 showed intense immunohistochemical staining of B23/nucleophosmin in cancer nuclei compared to adjacent normal cells in paraffin‐embedded prostate tissue. This preliminary study showed the potential of B23 as a tumor marker for human prostate cancer. Prostate 39:298–304, 1999. © 1999 Wiley‐Liss, Inc.

GLTSCR2 is an upstream negative regulator of nucleophosmin in cervical cancer

“…However, the majority of patients with these genetic changes are confined to specific tumour types, such as haematologic malignancies. Little is known about the mechanism for NPM overexpression in solid tumours such as gastrointestinal 36,37, ovarian 38 and prostatic cancers 39. In the present study, we demonstrated that GLTSCR2 overexpression shortened the half-life of NPM to approximately 10 hrs, augmented polyubiquitination, and promoted the proteasomal degradation of NPM.…”

Identification of proteins differentially expressed in adriamycin-resistant (pumc-91/ADM) and parental (pumc-91) human bladder cancer cell lines by proteome analysis

“…NPM1 was highly up-regulated in proliferative cells, and it promoted cell growth by inhibiting tumor suppressors (Ye 2005). NPM1 was over-expressed in many tumors and had been considered a marker for colon (Nozawa et al 1996), gastric (Tanaka et al 1992), and prostate carcinomas (Subong et al 1999) and thyroid tumors (Pianta et al 2010). Additionally, NPM1 had been found to be mutated in acute myeloid leukemia (AML; Falini et al 2005;Verhaak et al 2005).…”

DNA damage, p14ARF, Nucleophosmin (NPM/B23), and cancer

“…Finally, knock down of NPM in human tumor cells results in destabilization of ARF, decreased levels of ARF, and partial and specific delocalization of ARF (Korgaonkar et al 2005). Thus moderate levels of overexpressed NPM, a frequent feature of cancer (Nozawa et al 1996;Subong et al 1999), may be oncogenic through negative regulation of ARF.…”