Abstract 495: Leptin facilitates ovarian cancer metastasis through miR-28-3p and matrix metalloproteinase-1 in the omental tumor microenvironment

Abstract Advanced stage serous ovarian cancers spread beyond the pelvis and preferentially metastasize to the omentum, which is mainly composed of adipose tissue, suggesting that the omental microenvironment is a favorable niche for ovarian cancer cells. By comparing the transcriptome profiles of microdissected ovarian cancer tissues from the primary ovarian site and from the omental site, we identified matrix metalloproteinase-1 (MMP-1) as one of the most significant genes that was up-regulated in the omental site compared with that in the primary site. To identify mediators secreted by the omental microenvironment that up-regulated MMP-1 in the omental site tumors, transcriptome profiling was performed on microdissected ovarian tumor associated adipose tissue in the omental site and the ovarian stromal tissue in the primary ovarian tumor site. We identified leptin as one of the top differentially expressed genes in ovarian tumor associated adipose tissue in the omental site, suggesting that it might up-regulate MMP-1 in the omental ovarian cancer. To further delineate the role of MMP-1 in mediating the effect of leptin on ovarian cancer cell metastasis, ovarian cancer SKOV3 and OVCA433 cells were treated with leptin. The results showed that leptin increased MMP-1 mRNA and protein expression as assessed by quantitative RT-PCR and Western blot analyses, respectively. Furthermore, we demonstrated that leptin induced both the cell migration and invasion potential of SKOV3 and OVCA433 cells, and the effects were abrogated by transfecting cells with MMP-1 siRNAs. In addition, using Ion Torrent next generation sequencing, we found that miR-28-3p is down-regulated in leptin-treated SKOV3 and OVCA433 cells compared to the untreated cells, suggesting that it may play a role in mediating the effect of leptin on MMP-1 expression and the subsequent ovarian cancer cell motility and invasion potential. In conclusion, leptin secreted by the adipocytes in ovarian cancer associated omental microenvironment may be important in facilitating the ovarian cancer cell metastasis through the miR-28-3p/MMP-1 pathway. Citation Format: Chi Lam Au Yeung, Ngai Na Co, Tsz-Lun Yeung, Samuel C. Mok. Leptin facilitates ovarian cancer metastasis through miR-28-3p and matrix metalloproteinase-1 in the omental tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 495.