Correlations of Breast Carcinoma Biomarkers and p53 Tested by FASAY and Immunohistochemistry

Magnetic poly(glycidyl methacrylate) microspheres for protein capture

The efficient isolation and concentration of protein antigens from complex biological samples is a critical step in several analytical methods, such as mass spectrometry, flow cytometry and immunochemistry. These techniques take advantage of magnetic microspheres as immunosorbents. The focus of this study was on the development of new superparamagnetic polymer microspheres for the specific isolation of the tumor suppressor protein p53. Monodisperse macroporous poly(glycidyl methacrylate) (PGMA) microspheres measuring approximately 5 μm and containing carboxyl groups were prepared by multistep swelling polymerization of glycidyl methacrylate (GMA), 2-[(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA) and ethylene dimethylacrylate (EDMA) as a crosslinker in the presence of cyclohexyl acetate as a porogen. To render the microspheres magnetic, iron oxide was precipitated within their pores; the Fe content in the particles received ∼18 wt%. Nonspecific interactions between the magnetic particles and biological media were minimized by coating the microspheres with poly(ethylene glycol) (PEG) terminated by carboxyl groups. The carboxyl groups of the magnetic PGMA microspheres were conjugated with primary amino groups of mouse monoclonal DO-1 antibody using conventional carbodiimide chemistry. The efficiency of protein p53 capture and the degree of nonspecific adsorption on neat and PEG-coated magnetic microspheres were determined by western blot analysis.

gef gene expression in MCF-7 breast cancer cells is associated with a better prognosis and induction of apoptosis by p53-mediated signaling pathway

Breast cancer research has developed rapidly in the past few decades, leading to longer survival times for patients and opening up the possibility of developing curative treatments for advanced breast cancer. Our increasing knowledge of the biological pathways associated with the progression and development of breast cancer, alongside the failure of conventional treatments, has prompted us to explore gene therapy as an alternative therapeutic strategy. We previously reported that gef gene from E. coli has shown considerable cytotoxic effects in breast cancer cells. However, its action mechanism has not been elucidated. Indirect immunofluorescence technique using flow cytometry and immunocytochemical analysis were used to detect breast cancer markers: estrogen (ER) and progesterone (PR) hormonal receptors, human epidermal growth factor receptor-2 proto-oncogene (c-erbB-2), ki-67 antigen and p53 protein. gef gene induces an increase in ER and PR expressions and a decrease in ki-67 and c-erbB-2 gene expressions, indicating a better prognosis and response to treatment and a longer disease-free interval and survival. It also increased p53 expression, suggesting that gef-induced apoptosis is regulated by a p53-mediated signaling pathway. These findings support the hypothesis that the gef gene offers a new approach to gene therapy in breast cancer.

The biological, clinical and prognostic implications of p53 transcriptional pathways in breast cancers

We hypothesized that the functional status of p53 transcriptional pathways, rather than p53 protein expression alone, could accurately discriminate between low- and high-risk breast carcinoma (BC) and inform about individuals' tumour biological behaviour. To test this, we studied a well-characterized series of 990 BCs with long-term follow-up, immunohistochemically profiled for p53, its main regulators and downstream genes. Results were validated in an independent series of patients (n = 245) uniformly treated with adjuvant anthracycline-based chemotherapy. Eleven p53 transcriptional phenotypes were identified with just two main clinical outcomes. (a) Low risk/good prognosis group (active/partially inactive p53 pathways), defined as p53(+/-)/MDM4(+)/MDM2(+/-)/Bcl2(+/-)/p21(+/-), p53(-)/MDM4(-)/MDM2(+)/Bcl2(+)/p21(+/-) and p53(+/-)/MDM4(-)/MMD2(-)/Bcl2(+)/p21(+/-). These tumours had favourable clinicopathological characteristics, including ER(+) and long survival after systemic adjuvant-therapy (AT). (b) High risk/poor prognosis group (completely inactive p53 pathways), defined as p53(+/-)/MDM4(-) MDM2(-)/Bcl2(-)/p21(-), p53(-)/MDM4(-) MDM2(+)/Bcl2(-)/p21(-) and p53(+/-)/MDM4(-)/MDM2(-)/Bcl2(-)/p21(+). These tumours were characterized by aggressive clinicopathological characteristics and showed shortened survival when treated with AT. Completely inactive p53 pathways but intact p21 axis p53(+/-)/MDM4(-)/MDM2(-)/Bcl2(-)/p21(+) had the worst prognosis, particularly patients who received AT. Multivariate Cox regression models, including validated prognostic factors for both test and validation series, revealed that the functional status of p53 transcriptional pathways was an independent prognosticator for BC-specific survival (HR 2.64 and 4.5, p < 0.001, respectively) and disease-free survival (HR 1.93 and 2.5, p < 0.001, respectively). In conclusion, p53 functional status determined by assessment of p53 regulatory and downstream targets provides independent prognostic value and may help determine more adequate therapeutic regimens for specific subgroups of breast cancer patients.