Specific polypeptide differences in normal versus malignant human breast tissues by two-dimensional electrophoresis

Abstract

Postmitochondrial and cytosolic polypeptides were extracted from human breast tumors and non-malignant breast tissue and analyzed using high resolution two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Approximately 800-1000 postmitochondrial and 600-800 silver stained cytosolic polypeptides were detected over the pH range of 4.8 to 7.5 and molecular weight range of 18-120 kDa. The 2D-PAGE patterns of polypeptides from normal and malignant tissue were very similar, although both qualitative and quantitative polypeptide differences were noted. Six cytosolic polypeptides (pI/molecular weight X 10(-3) 5.20/80 kDa, 5.75/43, 6.25/40, 5.43/35, 5.45/34.5, 5.50/34 and 6.15/24 were expressed only in malignant tissues. One constitutive polypeptide, 7.25/52, was not detected in any of the malignant tissue samples. Quantitatively, marked differences in spot density were noted in polypeptides localized mainly in the molecular weight ranges of 22-40 kDa and pI ranges of 5.65-7.00. A general increase in polypeptide expression was noted in malignant tissues as compared to normal. Twenty-two polypeptides were significantly and consistently increased in tumor samples while only one polypeptide was decreased. One polypeptide, p24 (6.15/24) was expressed in greatest concentrations in tumors which also expressed the greatest estrogen receptor content. Expression of p24 was markedly reduced in normal tissue and malignant tissues expressing low levels of estrogen and progesterone receptors.

Breast Cancer

“…In 1984, it was found that most polypeptides were consistently present in both malignant and nonmalignant breast tissues, as only 10 polypeptides differed out of 350 resolved (9). Subsequently, using better technology, it was shown that of ϳ1000 silver-stained cytosolic polypeptides observed, the 2DE patterns from normal and malignant tissue differed in only 6 places qualitatively and only 22 places quantitatively (10,11). A more precise characterization of such polypeptide differences was published in the early 90s with the demonstration of a defect in tropomyosin 1, 2, and 3 expression in mammary carcinoma, suggesting that such abnormalities may play a role in breast neoplasia (12,13).…”

Proteomic definition of normal human luminal and myoepithelial breast cells purified from reduction mammoplasties

“…Early attempts to resolve proteins from breast material by two-dimensional PAGE were hampered by lack of reproducibility, low sensitivity, use of biopsy material containing mixed cell populations, and an inability to obtain sequence information from proteins of interest (15)(16)(17). More recently, significant progress in key areas of proteomics (18,19) has resulted in reports and databases with proteomes for normal and tumorderived breast cell lines in culture (20)(21)(22) and breast tissue from benign and malignant sources (23,24).…”

Polypeptide composition of normal and neoplastic human breast tissues and cells analyzed by two-dimensional gel electrophoresis

“…2D PAGE has been used to search for polypeptide markers for carcinomas of several human tissues, including stomach [22], colon [22,23,24,25], liver [22], kidney [22], prostate [26,27], and brain [28], as well as breast [22,29,30,31]. Steinbeck etal.…”