The acquisition of neuroendocrine (NE) characteristics by prostate cancer (PCa) cells is closely related to tumour progression and hormone resistance. The mechanisms by which NE cells influence PCa growth and progression are not fully understood. Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine involved in oncogenic processes, and MIF serum levels correlate with aggressiveness of PCa. Here, we investigated the regulation and the functional consequences of MIF expression during NE transdifferentiation of PCa cells. NE differentiation (NED) of LNCaP cells, initiated either by increasing intracellular levels of cAMP or by culturing cells in an androgen-depleted medium, was associated with markedly increased MIF release. Yet, intracellular MIF protein and mRNA levels and MIF gene promoter activity decreased during NED of LNCaP cells, suggesting that NED favours MIF release despite decreasing MIF synthesis. Adenoviral-mediated forced MIF expression in NE-differentiated LNCaP cells increased cell proliferation without affecting the expression of NE markers. Addition of exogenous recombinant MIF to LNCaP and PC-3 cells stimulated the AKT and ERK1/2 signalling pathways, the expression of genes involved in PCa, as well as proliferation and resistance to paclitaxel and thapsigargin-induced apoptosis. Altogether, these data provide evidence that increased MIF release during NED in PCa may facilitate cancer progression or recurrence, especially following androgen deprivation. Thus, MIF could represent an attractive target for PCa therapy.
Thomas Tawadros, Florian Alonso, Patrice Jichlinski, Noel Clarke, Thierry Calandra, Jacques-Antoine Haefliger, and Thierry Roger
Wafa Bouleftour, Karima Boussoualim, Sandrine Sotton, Cecile Vassal, Thierry Thomas, Nicolas Magné, and Aline Guillot
Prostate cancer (Pca) is the most commonly diagnosed cancer affecting men in France. Before the age of 75 years old, 1 in 8 French men will have Pca. Androgen deprivation therapies (ADT) remain the standard of care. Such therapies induces significant bone loss. Bone-remodelling cycle depends on the androgen synthesis signalling pathways. Furthermore, age-specific hormonal decline plays a key role in the decrease in bone mass. As a result, the older the patients, the more likely they are to have osteoporosis if they are treated with hormone therapy. Their risk of osteoporotic fracture has an impact on their quality of live and their capacity of independent living. In recent years, newer hormone therapies (acetate abiraterone, enzalutamide, apalutamide and darolutamide) have proved efficient in metastatic castration-resistant Pca (mCRPC) patients as well as in hormone naïve patients, and actually in non-metastatic diagnosis. The combination of these treatments with ADT highly inhibit androgen production pathways. They are prescribed to aged patients undergoing bone density loss after first generation anti-androgen treatment. Specific recommendations for bone health management in Pca patients are currently lacking. To date, bone mineral density in patients treated with second-generation hormone therapy has never been assessed in a prospective study. This review aims at reviewing what is known about the impact of second-generation hormonotherapy on bone microenvironment.
Thomas Cuny, Caroline Zeiller, Martin Bidlingmaier, Céline Défilles, Catherine Roche, Marie-Pierre Blanchard, Marily Theodoropoulou, Thomas Graillon, Morgane Pertuit, Dominique Figarella-Branger, Alain Enjalbert, Thierry Brue, and Anne Barlier
Pegvisomant (PEG), an antagonist of growth hormone (GH)-receptor (GHR), normalizes insulin-like growth factor 1 (IGF1) oversecretion in most acromegalic patients unresponsive to somatostatin analogs (SSAs) and/or uncontrolled by transsphenoidal surgery. The residual GH-secreting tumor is therefore exposed to the action of circulating PEG. However, the biological effect of PEG at the pituitary level remains unknown. To assess the impact of PEG in vitro on the hormonal secretion (GH and prolactin (PRL)), proliferation and cellular viability of eight human GH-secreting tumors in primary cultures and of the rat somatolactotroph cell line GH4C1. We found that the mRNA expression levels of GHR were characterized in 31 human GH-secreting adenomas (0.086 copy/copy β-Gus) and the GHR was identified by immunocytochemistry staining. In 5/8 adenomas, a dose-dependent inhibition of GH secretion was observed under PEG with a maximum of 38.2±17% at 1μg/mL (P<0.0001 vs control). A dose-dependent inhibition of PRL secretion occurred in three mixed GH/PRL adenomas under PEG with a maximum of 52.8±11.5% at 10μg/mL (P<0.0001 vs control). No impact on proliferation of either human primary tumors or GH4C1 cell line was observed. We conclude that PEG inhibits the secretion of GH and PRL in primary cultures of human GH(/PRL)-secreting pituitary adenomas without effect on cell viability or cell proliferation.