ABCC6P1 pseudogene induces ABCC6 upregulation and multidrug resistance in breast cancer.

Background: The elevated drug efflux by ABC transports has been considered the primary mechanism of drug resistance in cancer. Recently, non-coding RNAs, such as pseudogenes, have been proposed to be involved in transporter-mediated drug resistance in cancer. The human genome has 22 ABC transporter pseudogenes. Among these pseudogenes, ABCC6P1 has co-expression with its ancestral gene in various human tissues. In the present study, we assessed the effect of ABCC6P1 pseudogene overexpression on ABCC6 expression and drug resistance. Methods and results: The ABCC6P1 was transfected into the MCF-7 and MDA-MB-231 cells. In ABCC6P1-overexpressing cells, the ABCC6 level significantly increased. The results of cell treatment with doxorubicin, 5-fluorouracil, cisplatin, and paclitaxel showed that the survival of ABCC6P1-overexpressing cells was higher than normal cells. Furthermore, uptake of doxorubicin was lower in ABCC6P1-overexpressing cells. Conclusions: In conclusion, our results show that overexpression of ABCC6P1 pseudogene induces the drug resistance phenotype, possibly through activation of the ancestral gene. [ABSTRACT FROM AUTHOR]