Our study reveals for the first time, the molecular mechanism associated with lower levels of expression of the important tumor suppressor SMAR1 in higher grades of breast cancer.
Therefore, overexpression of SMAR1 may increase radiosensitivity to (89)SrCl2 in breast cancer cell line MCF7 by p53-dependent G2/M checkpoint arrest and apoptosis.
These results indicate a crucial role for SMAR1 in restraining breast cancer cell migration and suggest the candidature of this scaffold matrix-associated region-binding protein as a tumor suppressor.
SMAR1 (scaffold/matrix attachment region binding protein 1), is one such nuclear matrix associated protein whose expression is drastically reduced in higher grades of breast cancer.
Evaluation of SMAR1 and Cytokeratin 8 proteins in different grades of cancer using tissue microarray point out at the inverse expression profiles of these genes (i.e. low levels of SMAR1 correlating with high expression of Cytokeratin 8) in higher grades of breast cancer.
This was correlated with defective p53 expression in breast cancer where acetylated p53 is sequestered into the heterochromatin region and become inaccessible to activate SMAR1 promoter.