Abstract 3120: MMP-7 increases migration by decreasing intercellular cell junction complexes in prostate cancer microtumors formed by perlecan/HSPG2

Background: Polarized epithelium is stabilized by lateral cell-cell interactions via cell adhesion molecules (CAMs) and by cell-matrix interactions with basement membrane including with perlecan/HSPG2 (pln). Prostate cancer (PCa) patients with bone metastases have circulating pln fragments, with inverse correlation between MMP-7 staining and loss of pln in cancer tissue. Cleavage of pln by MMP-7 increases cell-matrix interactions and dysregulates cell signaling, permitting migration. We earlier showed pln domain IV-3 (DmIV-3) drives cell-cell cohesion and, when digested with MMP-7, drives cell dyscohesion. Methods: To evaluate the impact of MMP-7 and pln fragments on microtumor dyscohesion and cell migration, uniformly sized PCa microtumors were pre-formed in a microwell system. Pre-formed microtumors were transferred to Dm IV-3 or full length perlecan (FL pln) coated wells for 16-24 hrs. Microtumors were treated with MMP-7 alone or MMP-7 plus predigested Dm IV-3 fragments or MMP-7 plus FL pln fragments. For live cell imaging, tracking of migratory cells leaving microtumors was performed with Imaris software. Co-location of cell adhesion complex components was assessed with Imaris Spots. Results: Pre-formed microtumors cultured with DmIV-3 cleaved by MMP-7 showed lower Pearson9s correlation values at cell boundaries compared to microtumors treated with intact Dm IV-3. Line scan analysis revealed E-cadherin and F-actin fluorescent signals were enriched and co-aligned in microtumors treated with Dm IV-3; enrichment and co-alignment were reduced when DmIV-3 fragments and MMP-7 were present. Track number detected per cell cluster was highest in the presence of FL pln fragments plus MMP-7 along with a measurable change in distribution of track displacement lengths of cells toward high values. Conclusion: Boundary reorganization promotes a migratory cell phenotype in microtumors treated with MMP-7 and DmIV-3 fragments. DmIV-3 fragments generated by MMP-7 cleavage can enhance cell dyscohesion by disrupting interactions between CAMs. Ongoing work will identify DmIV-3 fragment(s) positively associated with tumor dyscohesion that play key roles in secondary metastasis formation. Following patterns of dyscohesion of pre-formed microtumors provides a good model to study dynamic changes in intercellular junction components and quantitate cell migration patterns that foster circulating tumor cell formation and metastasis. Citation Format: Lissette A. Cruz, Tristen V. Tellman, Oleg Igoshin, Daniel Carson, Mary (Cindy) Farach-Carson. MMP-7 increases migration by decreasing intercellular cell junction complexes in prostate cancer microtumors formed by perlecan/HSPG2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3120.