Silencing of Lactotransferrin expression by methylation in prostate cancer progression

Syed Shaheduzzaman, Anu Vishwanath, Bungo Furusato, Jennifer Cullen, Yongmei Chen, Lionel Bañez, Martin Nau, Lakshmi Ravindranath, Kee Hong Kim, Ahmed Mohammed, Yidong Chen, Mathias Ehrich, Vasantha Srikantan, Isabell A. Sesterhenn, David G. McLeod, Maryanne Vahey, Gyorgy Petrovics, Albert Dobi, Shiv Srivastava

Research output: Contribution to journalArticle

34 Scopus citations

Abstract

Background: Cancer cells gain selection advantages by the coordinated silencing of protective and by the activation of cell proliferation/cell survival genes. Evaluations of epithelial cell transcriptome of benign and malignant prostate glands by laser capture microdissection (LCM) identified Lactotransferrin (LTF) as the most significantly downregulated gene in prostate cancer (CaP) cells (p < 10-6). Frequent downregulation, significant association of LTF with PSA recurrence-free survival in CaP patients and the established anti-tumorigenic effects of LTF in experimental cancer models have provided impetus to evaluate LTF expression features and mechanisms in CaP specimens. Methods: LTF mRNA expression analysis was performed in LCM derived benign and malignant prostate epithelial cells by using Affymetrix GeneChip and QRT-PCR. LTF protein expression was assessed in tissue specimens by immunohistochemistry and in serum samples from CaP patients compared to healthy male control by using ELISA. Mechanism of LTF downregulation was analyzed in 5-azadeoxycytidine treated LNCaP and LAPC4 cells using MALDI-TOF MS. Proliferation and cell cycle analysis of CaP cells by FACS flow cytrometry was assessed in LNCaP cell cultures. Results: Quantitative analysis of LTF mRNA expression in tumor cells revealed marked downregulation of LTF with significant associations to decreased PSA recurrence-free survival of CaP patients (n = 100, p ≤ 0.0322). Moreover, low levels of LTF protein expression was observed in tumor tissues as well as in sera from CaP patients (p ≤ 0.0001). LTF promoter downstream CpG island methylation was found in LNCaP and LAPC4 cells. Furthermore, replenishing of LTF by supplementing growth media with LTF protein resulted in reduced cell growth. Cell cycle analysis revealed robust increases in apoptosis in response to LTF treatment. Conclusion: This study highlights the potential for LTF in chemoprevention and to become a biologically relevant prognostic marker of CaP, suggesting that silencing of the LTF gene may be causally linked to CaP progression.

Original languageEnglish (US)
Pages (from-to)1088-1095
Number of pages8
JournalCancer Biology and Therapy
Volume6
Issue number7
DOIs
StatePublished - Jul 2007
Externally publishedYes

Keywords

  • Chemoprevention
  • Downregulation
  • LTF
  • Methylation
  • PSA doubling time

ASJC Scopus subject areas

  • Molecular Medicine
  • Oncology
  • Pharmacology
  • Cancer Research

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  • Cite this

    Shaheduzzaman, S., Vishwanath, A., Furusato, B., Cullen, J., Chen, Y., Bañez, L., Nau, M., Ravindranath, L., Kim, K. H., Mohammed, A., Chen, Y., Ehrich, M., Srikantan, V., Sesterhenn, I. A., McLeod, D. G., Vahey, M., Petrovics, G., Dobi, A., & Srivastava, S. (2007). Silencing of Lactotransferrin expression by methylation in prostate cancer progression. Cancer Biology and Therapy, 6(7), 1088-1095. https://doi.org/10.4161/cbt.6.7.4327