Expression levels and dimer abundance of lamin A/C direct nuclear shape integrity in malignant cancer cells

Abstract

Abnormalities in nuclear morphology are an important diagnostic tool to determine malignancy in cancer cells and are characterised by nuclear blebbing and deformations. Nuclear shape is mostly maintained by a dense protein meshwork of lamins, consisting of 4 lamin subtypes, of which the individual contribution to nuclear shape maintenance remains elusive. In this study, we decouple the roles of lamin A, C, and B1 across cancer cell lines with varying malignant potential (HeLa, HT1080, and MDA-MB-231). Using single-cell correlation analysis, we directly link reduced lamin A/C, and not lamin B1, expression levels to nuclear deformability. We found that the nuclear shape of the more malignant MDA-MB-231 cells is approximately 4-fold more sensitive to lamin A/C than HeLa and HT1080 cells. Biochemical analyses reveal cell-type-specific variation in lamin A/C interactions and homodimer formation that correlates with nuclear shape deformations. In contrast to healthy mouse embryonic fibroblast cells, malignant cells exhibit reduced dimerisation, which correlates with nuclear deformability. As such, our study links, for the first time, the lamin A/C dimerisation state to nuclear abnormalities, thereby providing new avenues for investigating cancer progression.