# Structural Variants of Dermatan Sulfate Can Affect the Expression of Proteins Involved in Breast Cancer Cell Survival

## TL;DR

Dermatan sulfate's structural variants can influence proteins linked to breast cancer cell survival, promoting cell death through specific molecular pathways.

## Contribution

This study is the first to show that structural variants of dermatan sulfate can regulate cFLIP and HO-1 in breast cancer cells via PI3K/NFκB signaling.

## Key findings

- Dermatan sulfate can upregulate either long or short cFLIP splicing variants in a structure-dependent manner.
- Dermatan sulfate reduces HO-1 levels and influences the intracellular distribution of cFLIP and HO-1.
- These effects are mediated through PI3K and/or NFκB signaling pathways.

## Abstract

Dermatan sulfate (DS) is an animal glycosaminoglycan with significant structural heterogeneity and a high, but variable density of negative electric charge. Owing to these characteristics DS displays a high degree of biological reactivity that is subject to regulation. We previously demonstrated that structural variants of DS rapidly induce moderate necroptosis in luminal breast cancer cells. In the present study, we investigated the intracellular molecular mechanism(s) that may underlie this effect, focusing on the expression of key regulators of intrinsic (BCL-2A1) and extrinsic (cFLIP) apoptosis, autophagy (Beclin-1), and oxidative stress protection (heme oxygenase-1 (HO-1)). Using RT-qPCR, Western blotting, immunofluorescence, and pharmacological inhibition, we have shown for the first time that DS, depending on its structure and the cancer cell line, can rapidly, albeit transiently, upregulate either the long or short cFLIP splicing variant and also reduce the level of HO-1. These effects are mediated via DS-triggered PI3K and/or NFκB signaling. Moreover, DS can also influence the intracellular distribution of these proteins. In contrast, this glycan did not affect the expression of BCL-2A1 and BECN1. These findings indicate that DS induces coordinated molecular remodeling in luminal breast cancer cells that creates an intracellular environment favorable for necroptosis induction.