TCF3 is epigenetically silenced by EZH2 and DNMT3B and functions as a tumor suppressor in endometrial cancer

Area of Science:

• Oncology
• Molecular Biology
• Epigenetics

Background:

• Endometrial cancer (EC) is a prevalent gynecological malignancy with limited treatment options.
• The molecular drivers of EC progression remain largely unelucidated.
• Understanding EC pathogenesis is crucial for developing effective therapies.

Purpose of the Study:

• To investigate the roles of EZH2 and DNMT3B in endometrial cancer (EC) progression.
• To elucidate the molecular mechanisms by which EZH2 and DNMT3B influence EC cell proliferation.
• To evaluate the therapeutic potential of targeting EZH2 and DNMT3B in EC.

Main Methods:

• Analysis of EZH2 and DNMT3B expression in EC patient samples.
• In vitro and in vivo assays to assess cell proliferation, cell cycle, and colony formation.
• Mechanistic studies involving epigenetic repression of TCF3 by EZH2 and DNMT3B.
• Pharmacological inhibition of EZH2 and DNMT3B in preclinical EC models (CDX and PDX).

Main Results:

• EZH2 and DNMT3B were upregulated in EC and promoted cell proliferation.
• EZH2 epigenetically repressed TCF3, a transcriptional activator of p21, driving EC proliferation.
• DNMT3B methylated the TCF3 promoter, inhibiting its expression and promoting proliferation independently of EZH2.
• Elevated EZH2/DNMT3B and reduced TCF3/p21 expression correlated with poorer patient survival.
• Combined inhibition of EZH2 and DNMT3B synergistically blocked EC cell proliferation and tumor growth in vivo.

Conclusions:

• TCF3 acts as a tumor suppressor in EC, epigenetically silenced by EZH2 and DNMT3B.
• The EZH2/DNMT3B/TCF3/p21 signaling axis represents a promising therapeutic target for EC.
• Targeting EZH2 and DNMT3B demonstrates significant potential for novel EC treatment strategies.