Expression of retinoic acid receptor beta mediates retinoic acid-induced growth arrest and apoptosis in breast cancer cells

Abstract

The expression of the retinoic acid receptor beta (RAR beta) mRNA is absent or down-regulated in most human breast cancer cell lines.

To investigate the role RAR beta may have in regulating the proliferation of breast cancer cells, we used retroviral vector-mediated gene transduction to introduce the human RAR beta gene into two RAR beta-negative breast tumor cell lines, MCF-7 and MDA-MB-231.

RAR beta-transduced clones underwent growth inhibition associated with G1 arrest when treated with 1 microM all-trans-retinoic acid (RA). Moreover, the MCF7-RAR beta transduced clones also underwent apoptosis after 4 to 6 days of RA treatment.

The RA-induced growth arrest in MDA231-RAR beta transduced cells is associated with c-myc mRNA down-regulation, whereas the RA-mediated apoptosis of MCF7-RAR beta transduced cells is not associated with c-myc down-regulation.

These observations suggest a critical role for RAR beta in mediating growth arrest and apoptosis in breast cancer cells.

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