Placental protein-1 (Plac1) modulates immune tolerance in mammary tumor cells. Mus musculus

Plac1 is an X-linked (Xq26) trophoblast gene expressed at high levels in the placenta, at low levels in the testis, but not in other normal somatic tissues. However, it is re-expressed in several malignancies, including breast, colon, lung, gastric, liver and endometrial cancers as well as in most human cancer cell lines. Plac1 contains HLA-A2-restricted epitopes capable of eliciting a cytotoxic T lymphocyte (CTL) response against human breast cancer cells, and colorectal cancer patients with a Plac1-specific CTL response demonstrate long-term survival. To explore the role of Plac1 in cancer, mouse mammary tumor E0771 cells expressing high levels of Plac1 were transduced with a lentivirus expressing a Plac1 shRNA (E0771/shPlac1). Overall design: The RNeasy Mini Kit was used to purify total RNA from three independent cell culture samples for gene expression analysis. After isolation in parallel, 1 μg of each of the total RNA from E0771/Scram or E0771/Shplac1 was pooled prior to microarray gene expression analysis. E0771/Scram was considered as control group in this experiment.