CXC receptor-1 silencing inhibits androgen-independent prostate cancer

Nagarajarao Shamaladevi, Dominic A. Lyn, Diogo O. Escudero, Balakrishna L Lokeshwar

Research output: Contribution to journalArticle

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Abstract

The CXC receptor-1 (CXCR1) is a coreceptor for interleukin-8 (IL-8) and is expressed on both normal and tumor cells. The function of CXCR1 in prostate cancer was investigated by silencing its expression, using RNA interference. We established stable cell colonies of PC-3 cells, depleted of CXCR1, using lentiviral plasmids (pLK0.1puro) generating small hairpin RNA (shRNA) against CXCR1 mRNA. Stable shRNA transfectants (PLK1-PLK5) that express significantly reduced CXCR1 mRNA (≥90% down) and protein (≥43% down) or vector-only transfectants (PC-3V) were characterized. PLK cells showed reduced cell proliferation (down, ≥66%), due to cell cycle arrest at G1-S phase, decreases in Cyclin D1, CDK4, phosphorylated Rb, and extracellular signal-regulated kinase 1/2 levels compared with those in PC-3V cells. CXCR1 depletion lead to increases in spontaneous apoptosis bymitochondria-mediated intrinsic mechanism and increases in proapoptotic proteins (BAD, 40%; BAX, 12%), but decreases in antiapoptotic proteins (BCL2, down 38%; BCLxL, 20%). PLK2 cells grewas slow-growing tumors (decrease of 54%), compared with that of PC3V tumors in athymic mice. Ex vivo analyses of PLK2 tumor tissues showed reduced expression of Cyclin D1 and vascular endothelial growth factor, and increased apoptosis activity. Other IL-8-expressing prostate cancer cell lines also exhibited similar phenotypes when CXCR1 was depleted by CXCR1 shRNA transfection. In contrast to these cells, CXCR1 depletion had little effect on IL-8 ligand-deficient LNCaP cells. RNA interference rescue using mutated CXCR1 plasmids reversed the silencing effect of PLK2, thus demonstrating the specificity of phenotypic alteration by CXCR1 shRNA. These studies establish that CXCR1 promotes IL-8-mediated tumor growth.

Original languageEnglish (US)
Pages (from-to)8265-8274
Number of pages10
JournalCancer Research
Volume69
Issue number21
DOIs
StatePublished - Nov 1 2009

Fingerprint

Androgens
Prostatic Neoplasms
Interleukin-8
Small Interfering RNA
Cyclin D1
Neoplasms
RNA Interference
Plasmids
Apoptosis
Messenger RNA
Proteins
Mitogen-Activated Protein Kinase 3
Mitogen-Activated Protein Kinase 1
G1 Phase
Cell Cycle Checkpoints
S Phase
Nude Mice
Vascular Endothelial Growth Factor A
Transfection
Cell Proliferation

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

Cite this

CXC receptor-1 silencing inhibits androgen-independent prostate cancer. / Shamaladevi, Nagarajarao; Lyn, Dominic A.; Escudero, Diogo O.; Lokeshwar, Balakrishna L.

In: Cancer Research, Vol. 69, No. 21, 01.11.2009, p. 8265-8274.

Research output: Contribution to journalArticle

Shamaladevi, Nagarajarao ; Lyn, Dominic A. ; Escudero, Diogo O. ; Lokeshwar, Balakrishna L. / CXC receptor-1 silencing inhibits androgen-independent prostate cancer. In: Cancer Research. 2009 ; Vol. 69, No. 21. pp. 8265-8274.
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