There is increasing evidence that describes a histamine role in normal and cancer cell proliferation. To better understand the importance of histamine in breast cancer development, the expression o...

Histamine is a biogenic amine responsible for multiple biological actions including regulation of physiological functions of mammary gland. It has been postulated that histamine plays a critical ro...

Cancer is the second leading cause of death globally and its incidence and mortality are rapidly increasing worldwide. The dynamic interaction of immune cells and tumor cells determines the clinical outcome of cancer. Immunotherapy comes to the forefront of cancer treatments, resulting in impressive and durable responses but only in a fraction of patients. Thus, understanding the characteristics and profiles of immune cells in the tumor microenvironment (TME) is a necessary step to move forward in the design of new immunomodulatory strategies that can boost the immune system to fight cancer. Histamine produces a complex and fine‐tuned regulation of the phenotype and functions of the different immune cells, participating in multiple regulatory responses of the innate and adaptive immunity. Considering the important actions of histamine‐producing immune cells in the TME, in this review we first address the most important immunomodulatory roles of histamine and histamine receptors in the context of cancer development and progression. In addition, this review highlights the current progress and foundational developments in the field of cancer immunotherapy in combination with histamine and pharmacological compounds targeting histamine receptors.

Background: Glibenclamide (Gli) binds to the sulphonylurea receptor (SUR) that is a regulatory subunit of ATP-sensitive potassium channels (K_ATP channels). Binding of Gli to SUR produces the closure of K_ATP channels and the inhibition of their activity. This drug is widely used for treatment of type 2-diabetes and it has been signaled as antiproliferative in several tumor cell lines. In previous experiments we demonstrated the antitumoral effect of Gli in mammary tumors induced in rats. The aim of the present work was to investigate the effect of Gli on MDA-MB-231 breast cancer cell proliferation and to examine the possible pathways involved in this action. Results: The mRNA expression of the different subunits that compose the K_ATP channels was evaluated in MDA-MB-231 cells by reverse transcriptase-polymerase chain reaction. Results showed the expression of mRNA for both pore-forming isoforms Kir6.1 and Kir6.2 and for the regulatory isoform SUR2B in this cell line. Gli inhibited cell proliferation assessed by a clonogenic method in a dose dependent manner, with an increment in the population doubling time. The K_ATP channel opener minoxidil increased clonogenic proliferation, effect that was counteracted by Gli. When cell cycle analysis was performed by flow cytometry, Gli induced a significant cell-cycle arrest in G0/G1 phase, together with an up-regulation of p27 levels and a diminution in cyclin E expression, both evaluated by immunoblot. However, neither differentiation evaluated by neutral lipid accumulation nor apoptosis assessed by different methodologies were detected. The cytostatic, non toxic effect on cell proliferation was confirmed by removal of the drug. Combination treatment of Gli with tamoxifen or doxorubicin showed an increment in the antiproliferative effect only for doxorubicin. Conclusions: Our data clearly demonstrated a cytostatic effect of Gli in MDA-MB-231 cells that may be mediated through K_ATP channels, associated to the inhibition of the G1-S phase progression. In addition, an interesting observation about the effect of the combination of Gli with doxorubicin leads to future research for a potential novel role for Gli as an adjuvant in breast cancer treatment