| First Author | Lee II | Year | 2016 |
| Journal | Oncogene | Volume | 35 |
| Issue | 39 | Pages | 5191-201 |
| PubMed ID | 26996671 | Mgi Jnum | J:230789 |
| Mgi Id | MGI:5766069 | Doi | 10.1038/onc.2016.56 |
| Citation | Lee II, et al. (2016) Akt regulates progesterone receptor B-dependent transcription and angiogenesis in endometrial cancer cells. Oncogene 35(39):5191-201 |
| abstractText | Progestins have long been used clinically for the treatment of endometrial cancers; however, the response rates to progestin therapy vary and the molecular mechanisms behind progestin insensitivity are poorly understood. We hypothesized that in PTEN-mutated endometrial cancers, hyperactive Akt signaling downregulates progesterone receptor B (PRB) transcriptional activity, leading to overall impaired progestin responses. We report that inhibition of Akt with the Akt inhibitor, MK-2206 (MK), in conjunction with progestin (R5020) treatment, is sufficient to upregulate a subset of PRB target genes in Ishikawa cells stably expressing PRB (PRB-Ishikawa). Through gene ontology analysis of Akt-regulated PRB target genes, angiogenesis was found to be the principle process regulated by Akt-PRB. To further interrogate the mechanism by which Akt modulates PRB transcriptional activity, ChIP-Mass spectrometry was performed to identify potential cofactors that differentially interact with PRB in the presence of R5020 and MK+R5020. 14-3-3sigma was identified as a protein enriched in the MK+R5020 data set, and it was demonstrated that 14-3-3sigma is required for the upregulation in PRB target gene expression following inhibition of Akt. To determine the ramifications of MK+R5020 treatment on angiogenesis, in vitro assays were performed and combinatorial MK+R5020 treatment significantly decreased endothelial cell invasion and tube formation more than MK or R5020 treatment alone. Furthermore, we found that combinatorial MK-2206+progesterone treatments decreased angiogenesis and proliferation in the Pten(d/d) conditional mouse model of endometrial cancer. Taken together, these findings suggest that a combinatorial therapeutic approach utilizing Akt inhibitors with progestins may improve the efficacy of progestin therapy for the treatment of endometrial cancer. |
