Search

Supplementary Data from Sphingosine Kinase 1 Is Associated with Gastric Cancer Progression and Poor Survival of Patients

Purpose: The present study was to investigate the clinical significance of sphingosine kinase 1 (SPHK1), an oncoenzyme, in the development and progression of gastric cancer.Experimental Design: mRNA and protein levels of SPHK1 expression in normal gastric epithelial cells, gastric cancer cell lines, and paired gastric cancer lesions and the adjacent noncancerous tissues were examined using reverse transcription-PCR and Western blotting. Immunohistochemistry was employed to analyze SPHK1 expression in 175 clinicopathologically characterized gastric cancer cases. Statistical analyses were applied to derive prognostic and diagnostic associations.Results: Levels of SPHK1 mRNA and protein were higher in gastric cancer cell lines than in normal gastric epithelial cells. SPHK1 protein level was up-regulated in gastric cancer lesions compared with that in the paired adjacent noncancerous tissues. Gastric cancer tissues from 115 of 175 (65.7%) patients revealed high level of SPHK1 protein expression in contrast to the undetectable or marginally detectable expression of SPHK1 in the adjacent noncancerous gastric tissues. Significantly different expression levels of SPHK1 were found in patients at different clinical stages (P = 0.003), T classification (P = 0.035), and M classification (P = 0.020). Patients with higher SPHK1 expression had shorter overall survival time, whereas those with lower SPHK1 expression survived longer. Further multivariate analysis suggested that SPHK1 up-regulation was an independent prognostic indicator for the disease.Conclusions: SPHK1 protein could be a useful marker for the prognosis of gastric cancer. Further study on the potential use of SPHK1 as a therapeutic target is also warranted.

Supplementary Table 1, Figures 1-5 from Mel-18 Acts as a Tumor Suppressor by Repressing Bmi-1 Expression and Down-regulating Akt Activity in Breast Cancer Cells

The Bmi-1 oncogene is overexpressed in a number of malignancies including breast cancer. In addition to Bmi-1, mammalian cells also express four other polycomb group (PcG) proteins that are closely related to Bmi-1. Virtually nothing is known about the role of these PcG proteins in oncogenesis. We have recently reported that Mel-18, a Bmi-1–related PcG protein, negatively regulates Bmi-1 expression, and that its expression negatively correlates with Bmi-1 in proliferating and senescing human fibroblasts. Here, we report that the expression of Bmi-1 and Mel-18 inversely correlates in a number of breast cancer cell lines and in a significant number of breast tumor samples. Overexpression of Mel-18 results in repression of Bmi-1 and reduction of the transformed phenotype in malignant breast cancer cells. Furthermore, the repression of Bmi-1 by Mel-18 is accompanied by the reduction of Akt/protein kinase B (PKB) activity in breast cancer cells. Similarly, Bmi-1 knockdown using RNA interference approach results in down-regulation of Akt/PKB activity and reduction in transformed phenotype of MCF7 cells. Importantly, we show that overexpression of constitutively active Akt overrides tumor-suppressive effect of Mel-18 overexpression and the knockdown of Bmi-1 expression. Thus, our studies suggest that Mel-18 and Bmi-1 may regulate the Akt pathway in breast cancer cells, and that Mel-18 functions as a tumor suppressor by repressing the expression of Bmi-1 and consequently down-regulating Akt activity. [Cancer Res 2007;67(11):5083–9]

Purpose: This retrospective study aimed to examine the expression and localization of SAM68 (Src-associated in mitosis, 68 kDa) in a larger cohort of surgical specimens of renal cell carcinoma and their correlation with the progression of human renal cell carcinoma.Experimental Design: The protein and mRNA expression levels of SAM68 in normal renal tubular epithelial cells, renal cell carcinoma cell lines, as well as nine pairs of renal cell carcinoma and matched tumor-adjacent renal tissues were examined using reverse transcription-PCR and Western blot. Moreover, SAM68 protein expression and localization in 241 clinicopathologically characterized renal cell carcinoma samples were examined by immunohistochemistry. Prognostic and diagnostic associations were examined by statistical analyses.Results: SAM68 was markedly overexpressed in renal cell carcinoma cell lines and renal cell carcinoma tissues at both the transcriptional and translational levels. Immunohistochemical analysis revealed high SAM68 protein expression in 129 of the 241 (53.5%) paraffin-embedded archival renal cell carcinoma specimens. Moreover, there was a significant correlation between SAM68 expression and pathologic stage (P < 0.001), T classification (P = 0.003), N classification (P = 0.001), M classification (P = 0.006), and Fuhrman grade (P < 0.001). Patients with higher SAM68 expression had shorter overall survival time than patients with lower SAM68 expression, and the cytoplasmic localization of SAM68 significantly correlated with clinicopathologic grade and outcome. Multivariate analysis indicated that SAM68 protein overexpression and cytoplasmic localization were independent predictors for poor survival of renal cell carcinoma patients.Conclusions: Our results suggest that SAM68 could represent a novel and useful prognostic marker for renal cell carcinoma. High SAM68 expression and cytoplasmic localization are associated with poor overall survival in renal cell carcinoma patients. (Cancer Epidemiol Biomarkers Prev 2009;18(10):2685–93)

The Bmi-1 oncogene is overexpressed in a number of malignancies including breast cancer. In addition to Bmi-1, mammalian cells also express four other polycomb group (PcG) proteins that are closely related to Bmi-1. Virtually nothing is known about the role of these PcG proteins in oncogenesis. We have recently reported that Mel-18, a Bmi-1–related PcG protein, negatively regulates Bmi-1 expression, and that its expression negatively correlates with Bmi-1 in proliferating and senescing human fibroblasts. Here, we report that the expression of Bmi-1 and Mel-18 inversely correlates in a number of breast cancer cell lines and in a significant number of breast tumor samples. Overexpression of Mel-18 results in repression of Bmi-1 and reduction of the transformed phenotype in malignant breast cancer cells. Furthermore, the repression of Bmi-1 by Mel-18 is accompanied by the reduction of Akt/protein kinase B (PKB) activity in breast cancer cells. Similarly, Bmi-1 knockdown using RNA interference approach results in down-regulation of Akt/PKB activity and reduction in transformed phenotype of MCF7 cells. Importantly, we show that overexpression of constitutively active Akt overrides tumor-suppressive effect of Mel-18 overexpression and the knockdown of Bmi-1 expression. Thus, our studies suggest that Mel-18 and Bmi-1 may regulate the Akt pathway in breast cancer cells, and that Mel-18 functions as a tumor suppressor by repressing the expression of Bmi-1 and consequently down-regulating Akt activity. [Cancer Res 2007;67(11):5083–9]