The LINC Complex: A Molecular and Biomechanical Investigation into Breast Cancer Cell Migration

Abstract

Cell motility is an important feature during physiological conditions such as in development and wound healing. However, cell migration is also associated with a plethora of debilitating diseases including cancer metastasis. The LInker of the Nucleoskeleton and Cytoskeleton (LINC) complex mechanically tethers the nucleoskeleton to the cytoskeleton to enable force transmission though the nuclear envelope in response to external stimuli. A conserved interaction between Sad1-UNC- 84 (SUN) and Klarsicht, ANC-1 and SYNE/nesprin-1 and -2 Homology (KASH) proteins can be found in the heart of the LINC complex. The LINC complex is thought to govern nuclear envelope architecture and biomechanics, which can be determining factors during restrictive cell migration. Hence, shedding more light onto the role and regulation of the LINC complex could contribute towards a novel understanding of the mechanisms underlying cancer cell invasion and migration.

This project aimed to investigate variations between LINC complex composition and disulphide-dependent interactions in healthy breast epithelia compared to highly metastatic breast cancer cells. Additionally, we assessed the effects of thapsigargin- induced ER stress on LINC complex biology to find that nuclear envelope architecture, composition and chromatin organization are regulated by the LINC complex. Disruption of the conserved disulphide linkage within the SUN/KASH interaction increased directional cell migration in MDA-MB-231 cells but not in HaCaT cells, supporting the idea that different LINC complexes exist in different cell types. Lastly, we investigated the effects of pharmacological inhibition of protein disulphide isomerase (PDI) on the LINC complex. Our results suggest that PDI is unlikely to interact with the LINC complex directly, although it has important functions in promoting 2D and 3D breast cancer cell migration.

Overall, our results suggest that LINC complex conformations are cell type specific while LINC complex disruptions increase the migratory capabilities of MDA-MB-231 breast cancer cells during 2D and space-restrictive 3D migration.