Human ex vivo prostate tissue model system identifies ING3 as an oncoprotein

Area of Science:

• Molecular Biology
• Cancer Research
• Epigenetics

Background:

• The INhibitor of Growth (ING) family, including ING1 and ING2, has been characterized as tumor suppressors in preclinical models.
• The specific roles of other ING proteins, such as ING3, in cancer development and cellular proliferation remain largely undefined.

Purpose of the Study:

• To investigate the function of ING3 in cellular proliferation and its potential role in cancer.
• To determine if ING3 acts as a tumor suppressor or oncogene.

Main Methods:

• Ex vivo transduction of benign prostate hyperplasia tissues with lentiviral particles to express ING proteins.
• Assessment of cellular proliferation using H3S10phos immunohistochemistry (IHC).
• Analysis of ING3 expression in prostate cancer tissue microarrays (TMA) and gene expression profiling via DNA microarray and qPCR.

Main Results:

• ING3 overexpression was found to stimulate cellular proliferation in ex vivo tissues and transform normal human dermal fibroblasts.
• Elevated ING3 levels in prostate cancer samples correlated with reduced patient survival.
• Gene silencing demonstrated that ING3 is essential for the proliferation of breast, ovarian, and prostate cancer cells.
• ING3 regulates cell cycle gene expression by interacting with chromatin modifiers and H3K4me3 marks.

Conclusions:

• ING3 functions as an oncogene, promoting cellular proliferation and cancer progression.
• This study reclassifies ING3 from a potential tumor suppressor to a bona fide oncoprotein.
• The findings shift the paradigm regarding the role of ING proteins in cancer biology.