# GRB2 Promotes Malignant Behaviors of Breast Cancer by Modulating the Global Expression and Alternative Splicing Profiles in SK‐BR‐3 Cells Through Binding mRNA

## TL;DR

GRB2 promotes breast cancer by regulating mRNA splicing and gene expression, potentially offering a new target for treatment.

## Contribution

GRB2's role in modulating mRNA splicing and gene expression in HER2-overexpression breast cancer is newly identified.

## Key findings

- GRB2 knockdown altered 396 gene expressions and caused 956 alternative splicing events in SK-BR-3 cells.
- GRB2 binds to mRNA intron regions, with UUAGC and UUGGUUGG as potential binding motifs.
- 63 genes with GRB2 binding sites and 66 genes related to splicing events were identified, linking GRB2 to cancer progression.

## Abstract

The flexible protein GRB2 interacts with HER1–4 on the cell surface and regulates the development of tumor cells; meanwhile, it is also an RBP that plays an important role in post‐transcriptional regulation in eukaryotes, which affects every stage of mRNA synthesis, modification, splicing, and stabilization. Although some studies have found a connection between GRB2 and HER2‐overexpression breast cancer, highlighting the potential of GRB2 as a novel biomarker that stimulates tumor growth, limited data were available to elaborate on their interaction mechanisms.

In this research, we found 396 different gene expressions between the Grb2‐knockdown group and the SK‐BR‐3 group by the RNA sequencing approach. After GRB2 was knocked down, 956 alternative splicing events occurred.

The fRIP‐seq results showed that GRB2‐binding reads were significantly enriched in the intron region, indicating that UUAGC and UUGGUUGG might be the binding motifs. An integration analysis of DEGs with the peak genes of fRIP‐seq revealed that 63 genes possess GRB2 binding sites on their mRNAs or antisense RNAs. By integration analysis of AS events with the peak genes of fRIP‐seq, 66 genes related to AS events were found.

Above, these AS events may be regulated by GRB2 to promote the progression of HER2‐overexpression breast cancer.

GRB2 as a flexible protein and an RBP that is involved in post‐transcriptional regulation in eukaryotes, influencing all stages of mRNA synthesis, modification, splicing, and stabilization.