# Fucoidan from Lessonia trabeculata Induces Apoptosis through Caspase Dependent and Caspase-Independent Activation in 4T1 Breast Adenocarcinoma In Vitro

## TL;DR

Fucoidan from Lessonia trabeculata induces apoptosis in breast cancer cells through both caspase-dependent and caspase-independent pathways.

## Contribution

This study demonstrates FLt's dual apoptotic mechanisms in 4T1 breast cancer cells.

## Key findings

- FLt induces apoptosis via caspase-dependent and caspase-independent pathways in 4T1 cells.
- FLt reduces antiapoptotic gene expression and increases proapoptotic gene expression.
- DNA fragmentation and annexin V results suggest both apoptotic and necrotic cell death.

## Abstract

Experiments conducted on triple-negative breast cancer have shown that fucoidan from Lessonia trabeculata (FLt) exhibits cytotoxic and antitumor properties. However, further research is necessary to gain a complete understanding of its bioactivity and level of cytotoxicity. The cytotoxic effect of FLt was determined by the 2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Apoptosis was analyzed using annexin V and caspase 3/7 staining kit and DNA fragmentation. In addition, transcriptional expression of antiapoptotic (Bcl-2 and XIAP) and proapoptotic (caspase 8, caspase 9, and AIF) genes were analyzed in TNBC 4T1 cells. After 72 h of culture, the IC50 for FLt was 561 μg/mL, while doxorubicin (Dox) had an IC50 of 0.04 μg/mL. In addition, assays for FLt + Dox were performed. Annexin V and caspase 3/7 revealed that FLt induces early and late-stage apoptosis. DNA fragmentation results support necrotic death of 4T1 cells. Similarly, transcripts that prevent cell death were decreased, while transcripts that promote cell death were increased. This study showed that FLt induces apoptosis by both caspase-dependent and caspase-independent mechanisms. These findings suggest that FLt may have potential applications in breast cancer treatment. Further research will provide more information to elucidate the mechanism of action of FLt.