Expression of lactate/H⁺ symporters MCT1 and MCT4 and their chaperone CD147 predicts tumor progression in clear cell renal cell carcinoma: immunohistochemical and The Cancer Genome Atlas data analyses.

Clear cell renal cell carcinomas (ccRCCs) have inactivation of the von Hippel-Lindau protein, leading to the accumulation of hypoxia-inducible factor-α (HIF-α). HIF-1α induces aerobic glycolysis, the Warburg effect, whereas HIF-2α functions as an oncoprotein. Lactate transport through monocarboxylate transporters (MCTs) and the chaperone CD147 is essential for high glycolytic cancer cell survival. To elucidate the clinical significance of MCT1, MCT4, and CD147 expression, we investigated their expressions by immunohistochemistry in ccRCC specimens and validated the results by an open-access The Cancer Genome Atlas data analysis. Overexpression of MCT1, MCT4, and CD147 was observed in 49.4% (89/180), 39.4% (71/180), and 79.4% (143/180) of ccRCC patients, respectively. High MCT1 expression was associated with older age (P = .017), larger tumor size (P = .015), and advanced TNM stage (P = .012). However, MCT4 overexpression was not related to any variables. CD147 overexpression correlated with high grade (P = .005), tumor necrosis (P = .016), and larger tumor size (P = .038). In univariate analysis, high expression of MCT1 (P < .001), MCT4 (P = .016), and CD147 (P = .02) was linked to short progression-free survival. In multivariate analysis, high MCT1 expression was associated with worse progression-free survival (P = .001). In conclusion, high expression of MCT1 and CD147 is associated with poor prognostic factors. Overexpression of MCT1, MCT4, and CD147 predicts tumor progression. Reversing the Warburg effect by targeting the lactate transporters may be a useful strategy to prevent ccRCC progression.

Kim Y ，Choi JW ，Lee JH ，Kim YS ... -  《-》

Prognostic significance of lactate/proton symporters MCT1, MCT4, and their chaperone CD147 expressions in urothelial carcinoma of the bladder.

To investigate the prognostic significance of lactate/proton monocarboxylate transporters MCT1, MCT4, and their chaperone CD147 expressions in urothelial carcinoma of the bladder (UCB). We examined the expressions of MCT1, MCT4, and CD147 proteins in a total of 360 cases of UCB by immunohistochemistry. The immunohistochemical expressions were quantified using an ImageJ-based analysis program. MCT1, MCT4, and CD147 expressions were increased in 130 (36.1%), 168 (46.7%), and 228 (63.3%) UCB cases, respectively. Most tumor cells showed diffuse membranous staining, whereas normal urothelial cells showed negative or weak staining. High levels of MCT1 expression correlated with high World Health Organization grade (P<.001), advanced tumor node metastasis (TNM) stage (P<.001), nonpapillary growth type (P<.001), and lymphatic tumor invasion (P=.010), whereas high levels of MCT4 expression did not significantly correlate with any of these variables. High CD147 expression was associated with high World Health Organization grade (P<.001), advanced tumor node metastatis stage (P<.001), and nonpapillary growth type (P=.003). Univariate analyses revealed that high MCT1 (P<.001) and CD147 (P=.029) expressions were associated with poor overall survival and that high MCT4 expression was correlated with poor recurrence-free survival (P=.036). Multivariate analyses revealed that high MCT1 and MCT4 expressions were independent prognostic factors for poor overall survival and poor recurrence-free survival, respectively, in UCB patients. Our results indicate that increased MCT1, MCT4, and CD147 expressions have prognostic implications in UCB and suggest their roles in urothelial cancer metabolism.

Choi JW ，Kim Y ，Lee JH ，Kim YS ... -  《-》

The two glycolytic markers GLUT1 and MCT1 correlate with tumor grade and survival in clear-cell renal cell carcinoma.

Ambrosetti D ，Dufies M ，Dadone B ，Durand M ，Borchiellini D ，Amiel J ，Pouyssegur J ，Rioux-Leclercq N ，Pages G ，Burel-Vandenbos F ，Mazure NM ... -  《-》

Monocarboxylate transporters MCT1 and MCT4 are independent prognostic biomarkers for the survival of patients with clear cell renal cell carcinoma and those receiving therapy targeting angiogenesis.

Prognostic biomarkers for patients with clear cell renal cell carcinoma (ccRCC), particularly those receiving therapy targeting angiogenesis, are not well established. In this study, we examined the correlations of monocarboxylate transporter 1 (MCT1) and MCT4, 2 critical transporters for glycolytic metabolism, with various clinicopathological parameters as well as survival of patients with ccRCC and those treated with vascular endothelial growth factor receptor (VEGFR) inhibitors. A cohort of 150 ccRCC patients were recruited into this study. All patients underwent radical or partial nephrectomy as the first-line treatment, and 38 received targeted therapy (sorafenib or sunitinib) after the surgery. Expression levels of MCT1, MCT4, and CD34 were examined by immunohistochemistry. Correlations between MCT1 or MCT4 expression and different clinicopathological parameters or patient survival were analyzed among all as well as patients receiving targeted therapy. MCT1 or MCT4 expression did not significantly correlate with sex, age, tumor diameter, microvascular density, tumor staging, pathological Furmann grade, or MSKCC (P>0.05). High expression of either MCT1 or MCT4 significantly correlated with reduced overall survival (OS) and progression-free survival (PFS) among the total cohort of ccRCC patients. For patients receiving targeted therapy, high expression of either MCT1 or MCT4 significantly correlated with reduced PFS, but not OS. Both conditions were independent prognostic biomarkers for reduced PFS among all patients or those receiving targeted therapy. MCT1 and MCT4 are prognostic biomarkers for patients with ccRCC or those receiving targeted therapy. High expression of these 2 proteins predicts reduced PFS in these patients.

Cao YW ，Liu Y ，Dong Z ，Guo L ，Kang EH ，Wang YH ，Zhang W ，Niu HT ... -  《-》

DNA methylation of the SLC16A3 promoter regulates expression of the human lactate transporter MCT4 in renal cancer with consequences for clinical outcome.

The monocarboxylate transporter 4 (MCT4) is a metabolic target in tumor biology because it mediates lactate transport across membranes resulting in antiapoptotic effects. Cell experiments support the importance of MCT4 in clear cell renal cell carcinoma (ccRCC). In this study, we assessed the prognostic potential of MCT4 expression in ccRCC and its epigenetic regulation by DNA methylation as novel predictive marker for patient outcome using independent ccRCC cohorts. MCT4 protein expression was quantified in 207 ccRCC and corresponding nontumor tissues. Data of an independent ccRCC cohort from The Cancer Genome Atlas (TCGA) were analyzed on MCT4 mRNA (n = 482) and DNA methylation (n = 283) level. The findings on MCT4 expression and DNA methylation in the SLC16A3 promoter were validated in a third cohort (n = 64). Promoter activity assays were conducted in four RCC cell lines. MCT4 protein expression was upregulated (P < 0.0001) in ccRCC and showed significant association with cancer-related death. Upregulation of MCT4 mRNA expression (P < 0.00001) was confirmed in the TCGA cohort. Single CpG sites correlated inversely with mRNA expression and were associated with overall survival in Kaplan-Meier analyses [HR = 0.39; 95% confidence interval (CI), 0.24-0.64; P[log-rank] = 1.23e(-04)]. Promoter activity studies confirmed MCT4 regulation by DNA methylation. The significant correlation between MCT4 protein and gene expression or DNA methylation at single CpG sites was validated in a third cohort. Again, higher methylation at individual CpG sites was associated with prolonged survival [HR = 0.05; 95% CI, 0.01-0.40; P[log-rank] = 6.91e(-05)]. We identified SLC16A3 promoter DNA methylation as a novel epigenetic mechanism for MCT4 regulation in ccRCC with first evidence of a biological rationale for prognosis and clinical outcome.

Fisel P ，Kruck S ，Winter S ，Bedke J ，Hennenlotter J ，Nies AT ，Scharpf M ，Fend F ，Stenzl A ，Schwab M ，Schaeffeler E ... -  《-》