# Microenvironment Rheology Modulates the Effect of the Anticancer Peptide CIGB300 on 3D Head and Neck Tumoroids

## TL;DR

This study shows how the stiffness of a 3D tumor environment affects the performance of an anticancer peptide called CIGB300.

## Contribution

The first investigation of CIGB300's diffusion in tunable hydrogels using fluorescence spectroscopy for drug screening.

## Key findings

- The antitumor activity of CIGB300 varies with the stiffness of the 3D tumoroid microenvironment.
- Fluorescence spectroscopy effectively tracks CIGB300's diffusion in hydrogels over time.
- CIGB300's structural and stability properties were characterized using spectroscopic methods.

## Abstract

3D cell systems for in vitro experimental studies are able to mimic the in vivo efficacy of drugs before they are tested on animals. However, many studies are still needed in order to mimic the physiological environment with 3D cell-growth systems. The mechano-physical properties of the microenvironment are relevant for the invasiveness of cancer cells and for their drug resistance. In this study, 3D tumoroids of human oral squamous cell carcinoma (OSCC) CAL27 cells of different stiffnesses were produced using a tunable PEG–silk fibroin hydrogel (PSF), and the antitumor activity of the peptide CIGB300, an anticancer therapeutic peptide, with respect to these 3D tumoroid models was assessed. Furthermore, spectroscopic studies on the CIGB300 peptide are reported regarding its structure, stability, aggregation and diffusion properties. For the first time, the diffusion of the peptide CIGB300 in tunable silk fibroin hydrogels of different stiffnesses is investigated over time via fluorescence spectroscopy as a potential tool in drug-screening using hydrogel-based 3D tumoroids.