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Period-2: a tumor suppressor gene in breast cancer.

Xiang S, Coffelt SB, Mao L, Yuan L, Cheng Q, Hill SM - J Circadian Rhythms (2008)

Bottom Line: The inhibitory effect of PER 2 on breast cancer cells was also demonstrated by its suppression of the anchorage-independent growth of MCF-7 cells as evidenced by the reduced number and size of colonies.A corresponding blockade of MCF-7 cells in the G1 phase of the cell cycle was also observed in response to the expression of PER 2 alone or in combination with CRY 2.Finally, our studies demonstrate that PER 2 expression in MCF-7 breast cancer cells is associated with a significant decrease in the expression of cyclin D1 and an up-regulation of p53 levels.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Structural and Cellular Biology, Tulane University Health Sciences Center, New Orleans, LA 70112, USA. smhill@tulane.edu.

ABSTRACT
Previous reports have suggested that the ablation of the Period 2 gene (Per 2) leads to enhanced development of lymphoma and leukemia in mice. Employing immunoblot analyses, we have demonstrated that PER 2 is endogenously expressed in human breast epithelial cell lines but is not expressed or is expressed at significantly reduced level in human breast cancer cell lines. Expression of PER 2 in MCF-7 breast cancer cells significantly inhibited the growth of MCF-7 human breast cancer cells, and, when PER 2 was co-expressed with the Crytochrome 2 (Cry 2) gene, an even greater growth-inhibitory effect was observed. The inhibitory effect of PER 2 on breast cancer cells was also demonstrated by its suppression of the anchorage-independent growth of MCF-7 cells as evidenced by the reduced number and size of colonies. A corresponding blockade of MCF-7 cells in the G1 phase of the cell cycle was also observed in response to the expression of PER 2 alone or in combination with CRY 2. Expression of PER 2 also induced apoptosis of MCF-7 breast cancer cells as demonstrated by an increase in PARP [poly (ADP-ribose) polymerase] cleavage. Finally, our studies demonstrate that PER 2 expression in MCF-7 breast cancer cells is associated with a significant decrease in the expression of cyclin D1 and an up-regulation of p53 levels.

No MeSH data available.


Related in: MedlinePlus

Expression of PER 2 in human breast epithelial and breast cancer cell lines. Total cellular protein was isolated from two immortalized human breast epithelial cell lines (HME-tert and MCF-10A), two ERα-positive human breast tumor cell lines (MCF-7 and T47D lines) and one ERα-negative human breast tumor cell lines (MDA-MB-231 line). One hundred micrograms of total cellular protein from each cell line was separated by 10% polyacrylamide gel electrophoresis and subjected to Western blot analysis using an antibody directed against the human PER 2 protein.
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Figure 1: Expression of PER 2 in human breast epithelial and breast cancer cell lines. Total cellular protein was isolated from two immortalized human breast epithelial cell lines (HME-tert and MCF-10A), two ERα-positive human breast tumor cell lines (MCF-7 and T47D lines) and one ERα-negative human breast tumor cell lines (MDA-MB-231 line). One hundred micrograms of total cellular protein from each cell line was separated by 10% polyacrylamide gel electrophoresis and subjected to Western blot analysis using an antibody directed against the human PER 2 protein.

Mentions: Total cellular protein was isolated from two immortalized human breast epithelial cell lines (HME-tert and MCF-10A), two ERα-positive human breast tumor cell lines (MCF-7 and T47D lines) and one ERα-negative human breast tumor cell lines (MDA-MB-231), and was examined by Western blot analysis using an antibody directed against the human PER 2 protein (Figure 1). Expression of PER 2 was evident in the two breast epithelial cell lines, but was not observed in MCF-7 and T47D cell lines. It was present in the MDA-MB-231 cell line, but at a level greatly reduced compare to the breast epithelial cell lines.


Period-2: a tumor suppressor gene in breast cancer.

Xiang S, Coffelt SB, Mao L, Yuan L, Cheng Q, Hill SM - J Circadian Rhythms (2008)

Expression of PER 2 in human breast epithelial and breast cancer cell lines. Total cellular protein was isolated from two immortalized human breast epithelial cell lines (HME-tert and MCF-10A), two ERα-positive human breast tumor cell lines (MCF-7 and T47D lines) and one ERα-negative human breast tumor cell lines (MDA-MB-231 line). One hundred micrograms of total cellular protein from each cell line was separated by 10% polyacrylamide gel electrophoresis and subjected to Western blot analysis using an antibody directed against the human PER 2 protein.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2365929&req=5

Figure 1: Expression of PER 2 in human breast epithelial and breast cancer cell lines. Total cellular protein was isolated from two immortalized human breast epithelial cell lines (HME-tert and MCF-10A), two ERα-positive human breast tumor cell lines (MCF-7 and T47D lines) and one ERα-negative human breast tumor cell lines (MDA-MB-231 line). One hundred micrograms of total cellular protein from each cell line was separated by 10% polyacrylamide gel electrophoresis and subjected to Western blot analysis using an antibody directed against the human PER 2 protein.
Mentions: Total cellular protein was isolated from two immortalized human breast epithelial cell lines (HME-tert and MCF-10A), two ERα-positive human breast tumor cell lines (MCF-7 and T47D lines) and one ERα-negative human breast tumor cell lines (MDA-MB-231), and was examined by Western blot analysis using an antibody directed against the human PER 2 protein (Figure 1). Expression of PER 2 was evident in the two breast epithelial cell lines, but was not observed in MCF-7 and T47D cell lines. It was present in the MDA-MB-231 cell line, but at a level greatly reduced compare to the breast epithelial cell lines.

Bottom Line: The inhibitory effect of PER 2 on breast cancer cells was also demonstrated by its suppression of the anchorage-independent growth of MCF-7 cells as evidenced by the reduced number and size of colonies.A corresponding blockade of MCF-7 cells in the G1 phase of the cell cycle was also observed in response to the expression of PER 2 alone or in combination with CRY 2.Finally, our studies demonstrate that PER 2 expression in MCF-7 breast cancer cells is associated with a significant decrease in the expression of cyclin D1 and an up-regulation of p53 levels.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Structural and Cellular Biology, Tulane University Health Sciences Center, New Orleans, LA 70112, USA. smhill@tulane.edu.

ABSTRACT
Previous reports have suggested that the ablation of the Period 2 gene (Per 2) leads to enhanced development of lymphoma and leukemia in mice. Employing immunoblot analyses, we have demonstrated that PER 2 is endogenously expressed in human breast epithelial cell lines but is not expressed or is expressed at significantly reduced level in human breast cancer cell lines. Expression of PER 2 in MCF-7 breast cancer cells significantly inhibited the growth of MCF-7 human breast cancer cells, and, when PER 2 was co-expressed with the Crytochrome 2 (Cry 2) gene, an even greater growth-inhibitory effect was observed. The inhibitory effect of PER 2 on breast cancer cells was also demonstrated by its suppression of the anchorage-independent growth of MCF-7 cells as evidenced by the reduced number and size of colonies. A corresponding blockade of MCF-7 cells in the G1 phase of the cell cycle was also observed in response to the expression of PER 2 alone or in combination with CRY 2. Expression of PER 2 also induced apoptosis of MCF-7 breast cancer cells as demonstrated by an increase in PARP [poly (ADP-ribose) polymerase] cleavage. Finally, our studies demonstrate that PER 2 expression in MCF-7 breast cancer cells is associated with a significant decrease in the expression of cyclin D1 and an up-regulation of p53 levels.

No MeSH data available.


Related in: MedlinePlus