Validation of real-time RT-PCR for analysis of human breast cancer cell lines resistant or sensitive to treatment with antiestrogens.

Abstract

Using a quantitative real-time RT-PCR technique we have compared the expression of a number of genes in two different human breast cancer model systems for development of acquired resistance to antiestrogens. The model system developed at the Danish Cancer Society comprises the cell lines MCF-7, MCF-7/TAM R -1, MCF-7/182 R -6 and MCF-7/182 R -7, and the model system developed at the Lombardi Cancer Research Center consists of the cell lines MCF-7/LCC1, MCF-7/LCC2 and MCF-7/ LCC9. The findings on the well-known parameters estrogen receptor (ER)α, progesterone receptor (PR) and epidermal growth factor receptor (EGFR) are in good agreement with previous reports, thus documenting the usefulness of the real-time RT-PCR technique for multiparametric RNA analysis. The gene expression levels in the two model systems were found to be quite similar in relation to ERα, AIB1 (amplified in breast cancer-1), breast cancer antiestrogen resistance gene 1 (BCAR1) and ErbB-2 mRNA expression, whereas significant differences were observed on the expression of ERβ, multidrug resistance gene 1 (MDR1), PR and EGFR. Furthermore, the presented data suggest that ERβ, AIB1, BCAR1, CYP19 and MDR1 are unlikely to be causally involved in development of antiestrogen resistance in these breast cancer cell lines.

Ethanol stimulates the secretion of matrix metalloproteinases 2 and 9 in MCF-7 human breast cancer cells

“…We determined the optimal concentration by analyzing its effect on the expression of a well-known estrogen responsive gene, the progesterone receptor (PR) (25). The concentration of 100 nM had the best efficiency, which is in accordance with a previous study (32). We observed that this concentration could inhibit E 2 -induced increase in the secretion of the two MMPs.…”

Activation of ErbB3, EGFR and Erk is essential for growth of human breast cancer cell lines with acquired resistance to fulvestrant

“…All ErbB receptors were expressed in the parental MCF-7 cells, but the level of EGFR mRNA was extremely low as also described in a previously published work [25]. Figure 1a shows mRNA levels of the four ErbB receptors in seven fulvestrant resistant sublines expressed relative to the level in parental MCF-7 cells.…”

Changes in expression of steroid receptors, their downstream target genes and their associated co-regulators during the sequential acquisition of tamoxifen resistance in vitro

“…Some examples of genes up-and down-regulated in MCF-7 MMU1 cells relative to wtMCF-7 cells following microarray analysis. ------------------------------------------------ ERα expression exceeded that of ERß in accord with other studies (32)(33)(34)(35)(36). This has also proven to be the case in a xenograft model of anti-estrogen resistance and in clinical breast cancer (37,38).…”

“…AIB-1 expression correlated with poorer prognosis in breast cancer and reduced response to hormonal therapy (15). Elevated levels of AIB-1 have been reported in other breast cancer cell studies (32,33,44,45). Elevated levels in our in vitro TAMr model strengthen the involvement of AIB-1 in breast carcinogenesis and its further elevation in TAMr suggests it may be contributory to this phenomenon.…”