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Down-regulation of PKCζ in renal cell carcinoma and its clinicopathological implications.

Pu YS, Huang CY, Chen JY, Kang WY, Lin YC, Shiu YS, Chuang SJ, Yu HJ, Lai MK, Tsai YC, Wu WJ, Hour TC - J. Biomed. Sci. (2012)

Bottom Line: Unfortunately, nearly all patients die of the metastatic and chemoresistant RCC.Interestingly, an increase of PKCζ expression was associated with the elevated tumor grade (P=0.04), but no such association was found in TNM stage (P=0.13).PKCζ expression was associated with tumorigenesis and chemoresistance in RCC.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Urology, National Taiwan University College of Medicine, Taipei, Taiwan.

ABSTRACT

Background: Metastatic renal cell carcinoma (RCC) is highly resistant to systemic chemotherapy. Unfortunately, nearly all patients die of the metastatic and chemoresistant RCC. Recent studies have shown the atypical PKCζ is an important regulator of tumorigenesis. However, the correlation between PKCζ expression and the clinical outcome in RCC patients is unclear. We examined the level of PKCζ expression in human RCC.

Methods: PKCζ mRNA and protein expressions were examined by real-time polymerase chain reaction (PCR) and immunohistochemistry (IHC) respectively in RCC tissues of 144 patients. Cellular cytotoxicity and proliferation were assessed by MTT.

Results: PKCζ expression was significantly higher in normal than in cancerous tissues (P<0.0001) by real-time PCR and IHC. Similarly, PKCζ expression was down-regulated in four renal cancer cell lines compared to immortalized benign renal tubular cells. Interestingly, an increase of PKCζ expression was associated with the elevated tumor grade (P=0.04), but no such association was found in TNM stage (P=0.13). Tumors with higher PKCζ expression were associated with tumor size (P=0.048). Expression of higher PKCζ found a poor survival in patients with high tumor grade. Down-regulation of PKCζ showed the significant chemoresistance in RCC cell lines. Inactivation of PKCζ expression enhanced cellular resistance to cisplatin and paclitaxel, and proliferation in HK-2 cells by specific PKCζ siRNA and inhibitor.

Conclusions: PKCζ expression was associated with tumorigenesis and chemoresistance in RCC.

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Down-regulation of PKCζ in RCC tissues. (A) Expression of PKCζ mRNA in 3 pairs of RCC and adjacent normal kidney tissues from 3 patients by cDNA microarray analysis. Fold change compared with normal kidney tissues. Paired sample t test was used to compare PKCζ expression in the normal and RCC tissues (*P < 0.001). (B) Real-time PCR analysis of PKCζ in 5 pairs of RCC (T) and adjacent normal kidney tissues (N) from 5 patients. (C) Expression of PKCζ protein in 8 pairs of normal and RCC tissues by Western blotting analysis. β-actin was used as an internal control (D) The ration of protein intensity of PKC ζ/β-actin from Figure 1(C) was examined by densitometer analysis. Paired sample t test was used to compare PKCζ expression in the normal and RCC tissues (*P < 0.05).
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Figure 1: Down-regulation of PKCζ in RCC tissues. (A) Expression of PKCζ mRNA in 3 pairs of RCC and adjacent normal kidney tissues from 3 patients by cDNA microarray analysis. Fold change compared with normal kidney tissues. Paired sample t test was used to compare PKCζ expression in the normal and RCC tissues (*P < 0.001). (B) Real-time PCR analysis of PKCζ in 5 pairs of RCC (T) and adjacent normal kidney tissues (N) from 5 patients. (C) Expression of PKCζ protein in 8 pairs of normal and RCC tissues by Western blotting analysis. β-actin was used as an internal control (D) The ration of protein intensity of PKC ζ/β-actin from Figure 1(C) was examined by densitometer analysis. Paired sample t test was used to compare PKCζ expression in the normal and RCC tissues (*P < 0.05).

Mentions: Three pairs of RCC and normal renal parenchymal tissues from the same patients were analyzed using cDNA microarray, showing PKCζ gene expression in the cancerous tissues was 3-fold lower than in the normal tissues (P < 0.0001, Figure 1A). PKCζ mRNA expression was determined with real-time PCR using five pairs of tissues including the three used in the cDNA microarray experiment (Figure 1B). PKCζ mRNA levels were significantly higher in normal than in cancerous tissues (Figure 1B). Similarly, the expression of PKCζ protein was estimated in eight pairs of tissues by Western blotting (Figure 1C and 1D).


Down-regulation of PKCζ in renal cell carcinoma and its clinicopathological implications.

Pu YS, Huang CY, Chen JY, Kang WY, Lin YC, Shiu YS, Chuang SJ, Yu HJ, Lai MK, Tsai YC, Wu WJ, Hour TC - J. Biomed. Sci. (2012)

Down-regulation of PKCζ in RCC tissues. (A) Expression of PKCζ mRNA in 3 pairs of RCC and adjacent normal kidney tissues from 3 patients by cDNA microarray analysis. Fold change compared with normal kidney tissues. Paired sample t test was used to compare PKCζ expression in the normal and RCC tissues (*P < 0.001). (B) Real-time PCR analysis of PKCζ in 5 pairs of RCC (T) and adjacent normal kidney tissues (N) from 5 patients. (C) Expression of PKCζ protein in 8 pairs of normal and RCC tissues by Western blotting analysis. β-actin was used as an internal control (D) The ration of protein intensity of PKC ζ/β-actin from Figure 1(C) was examined by densitometer analysis. Paired sample t test was used to compare PKCζ expression in the normal and RCC tissues (*P < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376037&req=5

Figure 1: Down-regulation of PKCζ in RCC tissues. (A) Expression of PKCζ mRNA in 3 pairs of RCC and adjacent normal kidney tissues from 3 patients by cDNA microarray analysis. Fold change compared with normal kidney tissues. Paired sample t test was used to compare PKCζ expression in the normal and RCC tissues (*P < 0.001). (B) Real-time PCR analysis of PKCζ in 5 pairs of RCC (T) and adjacent normal kidney tissues (N) from 5 patients. (C) Expression of PKCζ protein in 8 pairs of normal and RCC tissues by Western blotting analysis. β-actin was used as an internal control (D) The ration of protein intensity of PKC ζ/β-actin from Figure 1(C) was examined by densitometer analysis. Paired sample t test was used to compare PKCζ expression in the normal and RCC tissues (*P < 0.05).
Mentions: Three pairs of RCC and normal renal parenchymal tissues from the same patients were analyzed using cDNA microarray, showing PKCζ gene expression in the cancerous tissues was 3-fold lower than in the normal tissues (P < 0.0001, Figure 1A). PKCζ mRNA expression was determined with real-time PCR using five pairs of tissues including the three used in the cDNA microarray experiment (Figure 1B). PKCζ mRNA levels were significantly higher in normal than in cancerous tissues (Figure 1B). Similarly, the expression of PKCζ protein was estimated in eight pairs of tissues by Western blotting (Figure 1C and 1D).

Bottom Line: Unfortunately, nearly all patients die of the metastatic and chemoresistant RCC.Interestingly, an increase of PKCζ expression was associated with the elevated tumor grade (P=0.04), but no such association was found in TNM stage (P=0.13).PKCζ expression was associated with tumorigenesis and chemoresistance in RCC.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Urology, National Taiwan University College of Medicine, Taipei, Taiwan.

ABSTRACT

Background: Metastatic renal cell carcinoma (RCC) is highly resistant to systemic chemotherapy. Unfortunately, nearly all patients die of the metastatic and chemoresistant RCC. Recent studies have shown the atypical PKCζ is an important regulator of tumorigenesis. However, the correlation between PKCζ expression and the clinical outcome in RCC patients is unclear. We examined the level of PKCζ expression in human RCC.

Methods: PKCζ mRNA and protein expressions were examined by real-time polymerase chain reaction (PCR) and immunohistochemistry (IHC) respectively in RCC tissues of 144 patients. Cellular cytotoxicity and proliferation were assessed by MTT.

Results: PKCζ expression was significantly higher in normal than in cancerous tissues (P<0.0001) by real-time PCR and IHC. Similarly, PKCζ expression was down-regulated in four renal cancer cell lines compared to immortalized benign renal tubular cells. Interestingly, an increase of PKCζ expression was associated with the elevated tumor grade (P=0.04), but no such association was found in TNM stage (P=0.13). Tumors with higher PKCζ expression were associated with tumor size (P=0.048). Expression of higher PKCζ found a poor survival in patients with high tumor grade. Down-regulation of PKCζ showed the significant chemoresistance in RCC cell lines. Inactivation of PKCζ expression enhanced cellular resistance to cisplatin and paclitaxel, and proliferation in HK-2 cells by specific PKCζ siRNA and inhibitor.

Conclusions: PKCζ expression was associated with tumorigenesis and chemoresistance in RCC.

Show MeSH
Related in: MedlinePlus