PGRMC1 phosphorylation affects cell shape, motility, glycolysis, mitochondrial form and function, and tumor growth

BACKGROUND

Progesterone Receptor Membrane Component 1 (PGRMC1) is expressed in many cancer cells, where it is associated with detrimental patient outcomes. It contains phosphorylated tyrosines which evolutionarily preceded deuterostome gastrulation and tissue differentiation mechanisms.

RESULTS

We demonstrate that manipulating PGRMC1 phosphorylation status in MIA PaCa-2 (MP) cells imposes broad pleiotropic effects. Relative to parental cells over-expressing hemagglutinin-tagged wild-type (WT) PGRMC1-HA, cells expressing a PGRMC1-HA-S57A/S181A double mutant (DM) exhibited reduced levels of proteins involved in energy metabolism and mitochondrial function, and altered glucose metabolism suggesting modulation of the Warburg effect. This was associated with increased PI3K/AKT activity, altered cell shape, actin cytoskeleton, motility, and mitochondrial properties. An S57A/Y180F/S181A triple mutant (TM) indicated the involvement of Y180 in PI3K/AKT activation. Mutation of Y180F strongly attenuated subcutaneous xenograft tumor growth in NOD-SCID gamma mice. Elsewhere we demonstrate altered metabolism, mutation incidence, and epigenetic status in these cells.

CONCLUSIONS

Altogether, these results indicate that mutational manipulation of PGRMC1 phosphorylation status exerts broad pleiotropic effects relevant to cancer and other cell biology.

A novel approach to increase robustness, precision and high-throughput capacity of single cell gel electrophoresis

The routine use of single cell gel electrophoresis assay in medical diagnostics and biomonitoring is prevented by its high variability. Several factors have been identified and can be grouped into four main categories: 1) the biological sample, 2) the assay protocol, 3) the physical parameters during electrophoresis and 4) the analysis. Even though the scientific knowledge on assay variability is available, not much has been done so far to tackle the issues from the technological side. Therefore, this study addresses the question in how far the precise and accurate control over the physical parameters of electrophoresis is able to reduce variability of single cell gel electrophoresis assay results. All four above mentioned categories make up the overall assay variability. To resolve the contribution from a single category, the remaining three have to be kept as constant as possible. To achieve this we generated a set of x-ray treated control cells, worked according to a well-defined standard operating procedure and one single operator performed the analysis. Thereby variability resulting from the electrophoresis tank could be elucidated. We compared assay performance in two such tank systems: a newly developed electrophoresis tank that accurately controls voltage, temperature during the electrophoretic run and the homogeneity of the electric field, and a widely used commercially available standard platform tank. In summary, our results demonstrate that, irrespective of the cellular sample and its intrinsic biological variability, accurate control over physical parameters considerably increases repeatability, reproducibility and precision of single cell gel electrophoresis.