TIP60 up-regulates ΔNp63α to promote cellular proliferation

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Nonmelanoma skin cancer (NMSC) is a significant health burden in the US.
• ΔNp63α, a proto-oncogene, is overexpressed in squamous cell carcinoma (SCC) and linked to poor patient outcomes.
• The upstream regulation of ΔNp63α in SCC remains largely unknown.

Purpose of the Study:

• To identify novel upstream regulators of ΔNp63α.
• To investigate the role of TIP60 in the regulation of ΔNp63α expression and stability.
• To elucidate the mechanism by which TIP60 influences SCC cell proliferation.

Main Methods:

• Overexpression and silencing of TIP60 in multiple cell lines.
• Cycloheximide treatment to assess protein stabilization.
• Analysis of protein ubiquitination and proteasomal degradation.
• MTS assays and flow cytometry to evaluate cell proliferation and cell cycle progression.

Main Results:

• TIP60 was identified as a novel upstream regulator that up-regulates ΔNp63α expression.
• TIP60's catalytic activity stabilizes ΔNp63α protein levels by inhibiting ubiquitination and proteasomal degradation.
• TIP60-mediated stabilization of ΔNp63α is associated with increased acetylation.
• TIP60-induced ΔNp63α elevation promotes cellular proliferation via G2/M cell cycle progression.

Conclusions:

• TIP60 acts as a novel upstream regulator of ΔNp63α.
• TIP60 stabilizes ΔNp63α protein levels, potentially through acetylation and inhibition of degradation.
• TIP60-mediated ΔNp63α upregulation contributes to SCC progression by promoting cellular proliferation.