Hypoxia and Inflammation in Prostate Cancer Progression. Cross-talk with Androgen and Estrogen Receptors and Cancer Stem Cells.

Tumors are complex tissues in which transformed cells communicate with the surrounding microenvironment and evolve traits promoting their own survival and malignancy. Hypoxia and inflammation are constant characteristics of prostate tumor microenvironment influencing both cancer stem cells and differentiated tumor cells. HIFs and NF-kB are the key regulators of the transcriptional response to hypoxic and inflammatory stresses, respectively, and a crosstalk between HIFs and NF-kB pathways has been widely documented.

HIF3α: the little we know.

Hypoxia-inducible factors (HIFs) are key regulators of the transcriptional response to hypoxic stress. Three inducible isoforms of HIF are present in mammals. HIF1α and HIF2α are the best characterized and structurally similar isoforms, while HIF3α is the most distantly related and is less studied.

Distinct phenotypes of human prostate cancer cells associate with different adaptation to hypoxia and pro-inflammatory gene expression.

Hypoxia and inflammation are strictly interconnected both concurring to prostate cancer progression. Numerous reports highlight the role of tumor cells in the synthesis of pro-inflammatory molecules and show that hypoxia can modulate a number of these genes contributing substantially to the increase of cancer aggressiveness. However, little is known about the importance of the tumor phenotype in this process.

Modulators of HIF1α and NFkB in Cancer Treatment: Is it a Rational Approach for Controlling Malignant Progression?

HIF1α and NFkB are two transcription factors very frequently activated in tumors and involved in tumor growth, progression, and resistance to chemotherapy. In fact, HIF1α and NFkB together regulate transcription of over a thousand genes that, in turn, control vital cellular processes such as adaptation to the hypoxia, metabolic reprograming, inflammatory reparative response, extracellular matrix digestion, migration and invasion, adhesion, etc. Because of this wide involvement they could control in an integrated manner the origin of the malignant phenotype.

Action of retinoic acid receptor on EGFR gene transactivation and breast cancer cell proliferation: Interplay with the estrogen receptor.

In the present report, we investigated the action of retinoic acid (RA) on the transactivation of the epidermal growth factor receptor (EGFR) gene promoter. In a previous study, we showed that the estrogen receptor (ER) α activated by 17β-estradiol (E₂) increased EGFR expression by enhancing the binding of the transcription factor Sp1 to the EGFR minimal promoter in HeLa cells. Here, we demonstrate that ligand-activated RA receptor (RAR) α inhibited EGFR transactivation by competing with Sp1 for binding to the same promoter fragment in the same cell model.