S100P is selectively upregulated in tumor cell lines challenged with DNA cross-linking agents.

Department of Pathology, Vanderbilt University School of Medicine, Nashville, TN 37232-5310, USA.
Leukemia Research (Impact Factor: 2.69). 11/2005; 29(10):1181-90. DOI: 10.1016/j.leukres.2005.03.012
Source: PubMed

ABSTRACT Bifunctional alkylating agents that cross-link DNA are implicated in the pathogenesis of therapy related myelodysplastic syndromes (MDS) and MDS related acute myeloid leukemia (MDR-AML). We exposed HL60 cells to the highest level of bifunctional alkylating nitrogen mustard mechlorethamine (HN2) that was consistent with recovery following suppressed growth. Microarray analyses showed minor changes in transcripts in HN2 treated cells. A moderate up-regulation of S100P mRNA was consistently observed after 1 day of exposure to bifunctional alkylating agents and expression was not induced with monofunctional agents. Elevated S100P protein/antigen was not detected until days later in a subset of non-mitotic G2 cells. Elevated S100P protein persisted over the course of a delayed recovery phase. The results confirm recent reports indicating that S100P is a survival factor. In addition, our results indicate that S100P has a specific role in G2 cell function associated with a prolonged phase of recovery after exposure to bifunctional alkylating agents.

  • [Show abstract] [Hide abstract]
    ABSTRACT: S100P is a member of the S100 family of calcium-binding proteins involved in calcium sensing and signal transduction. Its abnormal expression and biological activities are linked to tumor phenotype, namely to increased survival, proliferation, invasion and metastatic propensity of tumor cells. Association of S100P with outcome of tumor treatment and preliminary data from S100P promoter analysis prompted us to study regulation of S100P expression by glucocorticoids, which are implicated in tumor response to chemotherapy. We showed that dexamethasone (DX), a representative glucocorticoid, was capable to induce activity of S100P promoter by means of increased expression, nuclear translocation, and transactivation properties of the glucocorticoid receptor (GR). Moreover, DX treatment led to decreased phosphorylation of ERK1/2, reduced transcriptional activity of AP1, and modulated activity of some additional transcription factors. We identified a promoter region responsible for DX-mediated transactivation and proved GR binding to S100P promoter. We found that the effect of DX was enhanced by partial but not complete inhibition of the MAPK/ERK pathway, supporting an active crosstalk between GR and MAPK/ERK signal transduction in control of S100P expression. On the other hand, suppression of GR mRNA level by transient siRNA expression resulted in reduced S100P transcription. The role of GR activation in S100P regulation was supported by co-expression of GR with S100P in cells treated with DX. These data suggest that S100P is a direct transcriptional target of glucocorticoid-mediated signaling in tumor cells that is activated through the interplay of GR and MAPK pathways.
    Journal of Cellular Biochemistry 07/2011; 112(11):3373-84. · 3.37 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: S100P is a 95-amino-acid protein and a member of the S100 family. It was first purified from placenta. The promoter area of S100P has binding sites for SMAD, STAT/CREB and SP/KLF, key regulatory elements participating in transcriptional activation of the S100P gene. Increased levels of S100P have been observed in multiple tumor cell lines and breast, pancreas, lung and ovary carcinomas. S100P has been shown to mediate tumor growth, metastasis and invasion through the binding of Ca(2+) ions, receptor for advanced glycation end products, cytoskeletal protein ezrin, calcyclin-binding protein/Siah-1-interacting protein and cathepsin D. S100P could potentially serve as diagnostic marker, prognostic/predictive indicator and therapy target for different carcinomas.
    Journal of Cancer Research and Clinical Oncology 09/2011; 138(1):1-9. · 2.91 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: • To investigate the role of S100 calcium-binding protein P (S100P) in the gain of cis-diamminedichloroplatinum (II) (cisplatin) resistance in bladder cancer, having previously found, with cDNA microarrays using two pairs of parental (T24, KK47) and their cisplatin-resistant bladder cancer cell lines (T24/DDP10, KK47/DDP20), that S100P mRNA expression was significantly reduced in cisplatin-resistant cells. • S100P mRNA and protein expression levels were investigated by northern and western blot analyses, respectively. • Intracellular S100P localization was examined by immunocytochemistry and immunohistochemistry. • S100P over-expression, obtained by transfection with S100P expression plasmid, was used to investigate whether or not S100P affected cellular resistance to cisplatin. • S100P mRNA showed increased expression by cisplatin stimulation in parental cell lines. • On the other hand, S100P mRNA and protein expression levels were markedly reduced in cisplatin-resistant cells. • The over-expression of S100P in resistant cells resulted in an increased sensitivity to cisplatin. • In bladder cancer cells, S100P was expressed and localized mainly in the nucleus. • S100P expression was also involved in cisplatin sensitivity. • S100P might thus represent a molecular marker predicting cisplatin sensitivity and a molecular therapeutic target for cisplatin-based chemotherapy.
    BJU International 04/2011; 107(7):1148-53. · 3.13 Impact Factor