Intrinsic Resistance to 5-Fluorouracil in a Brain Metastatic Variant of Human Breast Cancer Cell Line, MDA-MB-231BR
نویسندگان
چکیده
Although drug resistance is often observed in metastatic recurrence of breast cancer, little is known about the intrinsic drug resistance in such metastases. In the present study, we found, for the first time, that MDA-MB-231BR, a brain metastatic variant of a human breast cancer cell line, was refractory to treatment with 5-fluorouracil (5-FU) even without chronic drug exposure, compared to its parent cell line, MDA-MB-231, and a bone metastatic variant, MDA-MB-231SCP2. Both the mRNA and protein levels of COX-2 and BCL2A1 in MDA-MB-231BR were significantly higher than those in MDA-MB-231 or MDA-MB-231SCP2. Neither the COX-2 inhibitor celecoxib nor the NF-κB inhibitor BAY11-7082 could sensitize MDA-MB-231BR to 5-FU, indicating that COX-2 plays little, if any, role in the resistance of MDA-MB-231BR to 5-FU. Although BCL2-family inhibitor ABT-263 failed to sensitize MDA-MB-231BR to 5-FU at a dose at which ABT-263 is considered to bind to BCL2, BCL2-xL, and BCL2-w, but not to BCL2A1, ABT-263 did sensitize MDA-MB-231BR to 5-FU to a level comparable to that in MDA-MB-231 at a dose of 5 μM, at which ABT-263 may disrupt intracellular BCL2A1 protein interactions. More importantly, BCL2A1 siRNA sensitized MDA-MB-231BR to 5-FU, whereas the overexpression of BCL2A1 conferred 5-FU-resistance on MDA-MB-231. These results indicate that BCL2A1 is a key contributor to the intrinsic 5-FU-resistance in MDA-MB-231BR. It is interesting to note that the drug sensitivity of MDA-MB-231BR was distinct from that of MDA-MB-231SCP2 even though they have the same origin (MDA-MB-231). Further investigations pertinent to the present findings may provide valuable insight into the breast cancer brain metastasis.
منابع مشابه
Quercetin Synergistically Enhances the Anticancer Efficacy of Docetaxel through Induction of Apoptosis and Modulation of PI3K/AKT, MAPK/ERK, and JAK/STAT3 Signaling Pathways in MDA-MB-231 Breast Cancer Cell Line
Docetaxel is widely used in the treatment of metastatic breast cancer. However, its effectiveness is limited due to chemoresistance and its undesirable side effects. The combination of chemotherapeutic agents and natural compounds is an effective strategy to overcome drug resistance and the ensuing inevitable toxicities. Quercetin is a natural flavonoid with strong antioxidant and anticancer ac...
متن کاملBrain tumor imaging: imaging brain metastasis using a brain-metastasizing breast adenocarcinoma.
Brain metastases from primary or secondary breast tumors are difficult to model in the mouse. When metastatic breast cancer cell lines are injected directly into the arterial circulation, only a small fraction of cells enter the brain to form metastatic foci. To study the molecular and cellular mechanisms of brain metastasis, we have transfected MB-231BR, a brain-homing derivative of a human br...
متن کاملEstablishment of a 5-fluorouracil-resistant triple-negative breast cancer cell line.
Triple-negative breast cancers (TNBCs) are defined as tumors that lack expression of estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2. Clinically, TNBC patients are treated with cytotoxic drugs including 5-fluorouracil (5-FU). However, TNBCs develop resistance to such drugs after a series of treatments. To elucidate the mechanisms of drug resistance, establi...
متن کاملTHE EFFECT OF QUINACRINE ON THE EXPRESSION OF WNT3A GENE IN MDA-MB 231 AND MCF7 BREAST CANCER CELL LINES
Background & Aims: Triple-negative breast cancer cells refer to any breast cancer that does not express the genes for the estrogen, progesterone, and HER2 receptors. The Wnt signaling pathway is important in the development and progression of various types of cancers. Quinacrine, a derivative of 9-aminoacridine, has been shown to inhibit the growth of several types of cancer cells. In this stud...
متن کاملInteraction Between Ezrin and Cortactin in Promoting Epithelial to Mesenchymal Transition in Breast Cancer Cells
BACKGROUND Epithelial to mesenchymal transition (EMT) contributes to metastases in various types of tumors, and is also the key step in the breast cancer metastatic cascade. In our previous study, a mouse model containing human-derived normal breast tissue was established and allowed EMT/MET process of human breast cancer cells to be mimicked in a humanized mammary microenvironment. MATERIAL AN...
متن کامل