Selective estrogen receptor modulators and betulinic acid act synergistically to target ERα and SP1 transcription factor dependent Pygopus expression in breast cancer.

Aims: Estrogen and progesterone hormone receptor (ER and PR) expression in invasive breast cancer predicts response to hormone disruptive therapy. Pygopus2 (hPYGO2) encodes a chromatin remodelling protein important for breast cancer growth and cell cycle progression. The aims of this study were to determine the mechanism of expression of hPYGO2 in breast cancer and to examine how this expression is affected therapeutically.

Evidence of a novel role for Pygopus in rRNA transcription.

Increased protein synthesis during cell proliferation is accompanied by a compensatory increase in efficient ribosome production, but the mechanisms by which cells adapt to this requirement are not fully understood. In the present study, we demonstrate evidence that Pygo (Pygopus), a protein originally identified as a core component of the Wnt-β-catenin transcription complex is also involved in rRNA transcription during cancer cell growth. Pygo was detected in the nucleoli of several transformed cell lines and was associated with treacle and UBF (upstream binding factor), proteins that are essential for ribosome biogenesis in development and cancer.

Human papilloma virus (HPV) E7-mediated attenuation of retinoblastoma (Rb) induces hPygopus2 expression via Elf-1 in cervical cancer.

The human papillomavirus (HPV) is the etiologic agent of cervical cancer. In this study, we provide evidence for the human Pygopus (hPygo)2 gene as a cellular biomarker for HPV-related disease. In a tumor microarray of cervical cancer progression, hPygo2 levels were greater in high-grade lesions and squamous cell carcinomas than in normal epithelia.