Down-Regulation of SLC8A1 as a Putative Apoptosis Evasion Mechanism by Modulation of Calcium Levels in Penile Carcinoma

Author(s):Show less -

Munoz, Juan J. ^{[1, 2]} ; Drigo, Sandra A. ^[3] ; Barros-Filho, Mateus C. ^[1] ; Marchi, Fabio A. ^[1] ; Scapulatempo-Neto, Cristovam ^[4] ; Pessoa, Gustavo S. ^[5] ; Guimaraes, Gustavo C. ; Trindade Filho, Jose Carlos S. ^[3] ; Lopes, Ademar ^[6] ; Arruda, Marco A. Z. ^[5] ; Rogatto, Silvia R. ^{[1, 3]}

Affiliation

^[1] AC Camargo Canc Ctr, Int Res Ctr, Sao Paulo - Brazil

^[2] Sao Paulo State Univ Univ Estadual Paulista, Dept Genet, Inst Biosci, Botucatu, SP - Brazil

^[3] Sao Paulo State Univ Univ Estadual Paulista, Dept Urol, Fac Med, Botucatu, SP - Brazil

^[4] Barretos Canc Hosp, Dept Pathol, Sao Paulo - Brazil

^[5] Univ Estadual Campinas, Grp Spectrometry Sample Preparat & Mech, Campinas, SP - Brazil

^[6] AC Camargo Canc Ctr, Dept Pelv Surg, Sao Paulo - Brazil

• Document type: Journal article
• Source: JOURNAL OF UROLOGY; v. 194, n. 1, p. 245-251, JUL 2015.
• Web of Science Citations: 15

Abstract

Purpose: The SLC8A1 gene, which encodes the Na+/Ca2(+) exchanger, has a key role in calcium homeostasis. Our previous gene expression oligoarray data revealed SLC8A1 under expression in penile carcinoma. We investigated whether dysregulation of SLC8A1 expression is associated with apoptosis and cell proliferation in penile carcinoma via modulation of the calcium concentration. The underlying mechanisms of SLC8A1 under expression were also explored, focusing on copy number alteration and miRNA. Materials and Methods: Transcript levels of the SLC8A1 gene and miR-223 were evaluated by quantitative polymerase chain reaction to compare penile carcinoma samples with normal glans tissue. SLC8A1 copy number was evaluated by microarray based comparative genomic hybridization. In normal and tumor samples we investigated caspase-3 and Ki-67 immunostaining as well as calcium distribution by laser ablation imaging inductively coupled plasma mass spectrometry. Results: SLC8A1 under expression was detected in penile carcinoma samples (p = 0.001), confirming our previous data. It was not associated with gene copy number loss. In contrast, miR-223 over expression (p = 0.002) inversely correlated with its putative repressor SLC8A1 (r = -0.426, p = 0.015). SLC8A1 under expression was associated with decreased calcium distribution, high Ki-67 and low caspase-3 immunoexpression in penile carcinoma compared to normal tissue. Conclusions: Down-regulation of the SLC8A1 gene, most likely mediated by its regulator miR-223, can lead to decreased calcium in penile carcinoma and consequently to suppressed apoptosis and increased tumor cell proliferation. These data suggest that the miR-223-NCX1-calcium signaling axis may represent a potential therapeutic approach to penile carcinoma. (AU)

• FAPESP's process: 09/52088-3 - Cancer of the penis, a real Brazilian problem: from morphology to molecular etiopathogenesis
• Grantee: José Vassallo
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 10/51601-6 - Profile methyla tion in penile carcinoma
• Grantee: Silvia Regina Rogatto
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/21344-7 - Metallomics studies applied to genetically modified species of soybean [Glycine max (L.) Merrill] and Arabidopsis thaliana
• Grantee: Marco Aurelio Zezzi Arruda
• Support Opportunities: Regular Research Grants