Identification of the dopamine transporter SLC6A3 as a biomarker for patients with renal cell carcinoma

Abstract

BackgroundClear cell renal cell carcinoma (ccRCC) is among the most common human malignancies.MethodsIn order to provide better understanding of the molecular biology of ccRCC and to identify potential diagnostic/prognostic biomarker and therapeutic targets, we utilized a microarray to profile mRNA expression of corresponding normal and malignant renal tissues. Real-time PCR, Western Blot and immunohistochemistry were applied to study the expression of candidate biomarkers. ccRCC cell lines were treated with sertraline to inhibit the dopamine transporter SLC6A3.ResultsDifferential expression of fourteen mRNAs, yet not studied in ccRCC in depth, was confirmed using qPCR (upregulation: SLC6A3, NPTX2, TNFAIP6, NDUFA4L2, ENPP3, FABP6, SPINK13; downregulation: FXYD4, SLC12A1, KNG1, NPHS2, SLC13A3, GCGR, PLG). Up-/downregulation was also confirmed for FXYD4, KNG1, NPTX2 and SLC12A1 by Western Blot on the protein level. In contrast to the mRNA expression, protein expression of the dopamine transporter SLC6A3 was lower in ccRCC compared to normal renal tissue. Immunohistochemistry indicated that this decrease was due to higher concentrations of SLC6A3 in the proximal tubules. Immunohistochemical analyses further demonstrated that high SLC6A3 expression in ccRCC tissue was correlated with a shorter period of recurrence-free survival following surgery. Treatment of ccRCC cells with the SLC6A3 inhibitor sertraline induced dose-dependent cell-death.ConclusionOur study identified several novel biomarkers with diagnostic potential and further investigations on sertraline as therapeutic agent in ccRCC patients are warranted.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-016-0495-5) contains supplementary material, which is available to authorized users.

Relationship between anti-depressant use and lung cancer survival

“…(36,38,40) Norepinephrine was recently shown to inhibit the migratory ability of pancreatic cells(41) while as mentioned earlier, beta-adrenergic receptor blockade is also associated with improved outcomes. (6,42-44) Recent work also found that the dopamine transporter inhibitor, sertraline, induced cell death in renal cell carcinoma,(45) data that collectively implicate catecholamine biology in carcinogenesis. (32,33)…”

Systematic Expression Analysis of Mitochondrial Complex I Identifies NDUFS1 as a Biomarker in Clear-Cell Renal-Cell Carcinoma

“…Some subunits of the electron transport chain have been linked to RCC before: NDUFA4 expression is decreased in ccRCC and may predict unfavorable outcome following nephrectomy. 9 In contrast, NDUFA4L2, a paralogue of NDUFA4, is upregulated in RCC 10,11 and altered gene expression is associated with a poor prognosis. 11 The aim of this study was to develop a better understanding of the expression of the mitochondrial complex I subunits and to determine whether some subunits may have the potential to be used as a new biomarker.…”

Systematic expression analysis of the mitochondrial complex III subunits identifies UQCRC1 as biomarker in clear cell renal cell carcinoma

“…deregulated oxygen sensing is characterized by VHL/ HIF pathway alterations with subsequent upregulation of HIF-responsive genes and glucose transporters allowing the reliance on aerobic glycolysis [24]. We earlier reported dysregulation of the electron transport chain subunit NDUFA4 [25] and its paralogue NDUFA4L2 [26], and demonstrated an prognostic relevance of NDUFA4 [25]. There is evidence for an decreased expression level of the complex III in RCC [6,27] leading to decreased activity of the electron transport chain [27].…”

“…UQCRFS1 and UQCRC1 expression was further investigated in RCC, oncocytoma and benign renal tissue using a tissue microarray (published in [26]). Paraffin sections were cut at 5 μm thickness, deparaffinized using xylene and rehydrated in graded ethanol.…”