CD133 expression in renal cell carcinoma (RCC) is correlated with nuclear hypoxia-inducing factor 1α (HIF-1α).

Purpose: In our previous study, we have found that the hypoxia-inducible factor 1α (HIF-1α) is upregulated in renal cell carcinoma (RCC) tissues compared with para-cancer normal tissues by 2-dimensional polyacrylamide gel electrophoresis. It was reported that hypoxic conditions were correlated with cancer stem cell generation and HIF-1α acted as a transcription regulator in nuclear HIF-1α expression. Therefore, in this study we investigate the relation between CD133 and nuclear HIF-1α expression levels in RCC tissues. Methods: In this study 61 RCC tissues from the patients that treated with radical nephrectomy were collected. Then, we investigated the expression of CD133 and nuclear HIF-1α expression by immunohistochemistry. To verify the relation between CD133 and nuclear HIF-1α expression, we treated 786-O cells with cobalt chloride. The expression of CD133 on 786-O cells was analyzed by flowcytometry. Results: The immunohistochemical study showed that CD133 was correlated with tumor stage and metastatic stage, whereas nuclear HIF-1α had no association with clinicopathological parameters. However, the expression of nuclear HIF-1α was correlated with CD133. The CD133 expression in 786-O cells was enhanced by cobalt chloride, which meant that CD133 expression was affected by hypoxia. Conclusions: Our study showed that in RCC, CD133 expression was strongly related to nuclear HIF-1α and the expression of CD133 might be upregulated under hypoxia environment. [ABSTRACT FROM AUTHOR]