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. Similarly, androgen and estrogen signaling, that play important roles in the growth and function of normal prostate gland, when deregulated, have a significant part in the acquisition of hallmarks of malignant diseases. Moreover, androgen and estrogen receptors have been shown to intersect with the HIF/NF-kB signaling in prostate cancer. Aim of this review is to present the current knowledge regarding the crucial role, in prostate cancer progression, of a molecular network linking hypoxia, pro-inflammatory response and steroid receptors.