Innovative mouse models for the tumor suppressor activity of Protocadherin-10 isoforms

Area of Science:

• Molecular Biology
• Genetics
• Cancer Research

Background:

• Nonclustered mouse protocadherin genes (Pcdh) encode proteins with unique cytoplasmic domains distinct from classic cadherins.
• Alternative splice isoforms of Pcdh vary in cytoplasmic domain size.
• Gene silencing of protocadherins is implicated in human tumors, prompting investigation in mouse cancer models.

Purpose of the Study:

• To investigate the function of protocadherin-10 (Pcdh10) in mouse cancer models.
• To generate mouse models for studying Pcdh10's role in tumor initiation and progression.
• To analyze the tumor suppressive activity of Pcdh10 isoforms.

Main Methods:

• Generated mouse lines with floxed Pcdh10 alleles for complete or partial isoform ablation.
• Utilized a medulloblastoma model with Cre-mediated Pcdh10 ablation alongside Trp53 and Rb1 ablation.
• Established and analyzed tumor-derived cell lines for malignancy and response to Pcdh10 re-expression via lentiviral transduction.
• Performed RNA-Seq analyses to identify differentially expressed genes.

Main Results:

• Medulloblastomas and auricular (pinnal) tumors developed in the mouse model; Pcdh10 ablation aggravated both.
• Pinnal tumors originated from the perichondrial stem cell compartment.
• Re-expression of either short or long Pcdh10 isoforms counteracted malignancy in derived cell lines across multiple assays.
• RNA-Seq identified distinct sets of differentially expressed genes in Pcdh10-rescued cell lines.

Conclusions:

• A novel mouse model demonstrated the significant tumor suppressor activity of protocadherin-10 (Pcdh10) in vivo.
• The short isoform of Pcdh10 exhibited full tumor suppressor activity despite lacking conserved motifs.
• The study provides insights into the molecular mechanisms of tumor initiation and progression linked to PCDH10 silencing in human cancers.