# Visualizing Cytoskeletal Protein Reconstruction of Vulvar Cancer with Surface-Enhanced Raman Spectroscopy and Gold Nanoparticles

## TL;DR

The study uses Raman spectroscopy and gold nanoparticles to visualize cytoskeletal changes in vulvar cancer cells undergoing epithelial-mesenchymal transition.

## Contribution

A novel 3D SERS imaging method is introduced to track cytoskeletal protein transitions in vulvar cancer cells.

## Key findings

- Clobetasol treatment induces EMT in A431 cells, marked by E-cadherin loss and vimentin gain.
- 3D SERS imaging reveals unique cytoarchitectural features combining traits of A431 and NIH 3T3 cells.
- Raman signals distinguish protein interactions and folding dynamics during EMT.

## Abstract

Metastasis of epithelial
cancers often involves epithelial–mesenchymal
transition (EMT), characterized by changes in cytoskeletal and adhesion
protein expression. This includes the loss of the cell adhesion protein
E-cadherin and the gain of the cytoskeletal protein vimentin. Our
laboratory found that the epithelial vulvar cancer cell line A431
undergoes permanent loss of E-cadherin and gains vimentin expression
when treated with a corticosteroid known as clobetasol (referred to
as A431D cells). Clobetasol is commonly used to treat chronic vulvar
rashes, making our findings significant when considering the repercussions
of this treatment. Interestingly, the cells continued to express cytokeratin
8/18 in addition to vimentin. Raman spectroscopy has been used to
monitor EMT in breast and oral cancer. We used 3-dimensional Surface-Enhanced
Raman Scattering (SERS) imaging by utilizing colloidal gold nanoparticles.
By tracking protein interactions and surface composition in cells
before and after treatment with clobetasol, the distribution of the
transition can be reasoned and visualized. Spectral assignments revealed
the order of protein gains and losses, while the distinctness of the
collected signals from the literature signals provided information
about the folding, binding, and repelling forces between these cytoskeletal
proteins. The three-dimensional Raman imaging of the cytoplasmic region
of A431D cells exhibited unique features that combined the cytoarchitecture
of A431 cells (parent cells expressing cytokeratins 8 and 18) and
NIH 3T3 cells (used because they only express vimentin). This suggests
that Raman imaging can be used to delineate cells that contain multiple
types of intermediate filaments and serve as another method to identify
cells undergoing EMT.