Emerin mislocalization during chromatin bridge resolution can drive prostate cancer cell invasiveness in a collagen-rich microenvironment

Abstract

Micronuclei (MN) can form through many mechanisms, including the breakage of aberrant cytokinetic chromatin bridges. The frequent observation of MN in tumors suggests that they might not merely be passive elements but could instead play active roles in tumor progression. Here, we propose a mechanism through which the presence of micronuclei could induce specific phenotypic and functional changes in cells and increase the invasive potential of cancer cells. Through the integration of diverse in vitro imaging and molecular techniques supported by clinical samples from patients with prostate cancer (PCa) defined as high-risk by the D’Amico classification, we demonstrate that the resolution of chromosome bridges can result in the accumulation of Emerin and the formation of Emerin-rich MN. These structures are negative for Lamin A/C and positive for the Lamin-B receptor and Sec61β. MN can act as a protein sinks and result in the pauperization of Emerin from the nuclear envelope. The Emerin mislocalization phenotype is associated with a molecular signature that is correlated with a poor prognosis in PCa patients and is enriched in metastatic samples. Emerin mislocalization corresponds with increases in the migratory and invasive potential of tumor cells, especially in a collagen-rich microenvironment. Our study demonstrates that the mislocalization of Emerin to MN results in increased cell invasiveness, thereby worsening patient prognosis. Micronuclei, small nuclei formed during incorrect cell division, can signal genomic instability, often found in cancer. This research investigates how micronuclei may contribute to cancer progression, in the context of prostate cancer, by focusing on the nuclear envelope protein, Emerin. The team conducted experiments using different cell lines and patient samples to understand how Emerin’s misplacement from nuclear envelope to micronuclei can impact cancer cell behavior. The study involved analyzing cells for Emerin distribution, observing the effects of Emerin misplacement on cell movement and invasiveness, and examining prostate cancer tissue to see how these findings relate to the disease in patients. It was observed that the presence of Emerin-rich micronuclei correlates to more aggressive cancer behavior and could predict worse outcomes. Targeting the pathways leading to Emerin misplacement could offer novel strategies for treating aggressive prostate cancer. This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author.