The NKB/NK3R system dysregulation observed in leiomyoma may contribute to the pathological symptoms observed in women with leiomyomata.

No abstract

Organotypic cultures of tissue slices have been successfully established in lung, prostate, colon, gastric and breast cancer among other malignancies, but until now an ex vivo model based on tissue slices has not been established for uterine leiomyoma. In the present study, we describe a method for culturing tumour slides onto an alginate scaffold. Morphological integrity of tissue slices was maintained for up to 7 days of culture, with cells expressing desmin, estrogen and progesterone receptors. Driver mutations were present in the ex vivo slices at all-time points analyzed. cultivated tumour slices responded to ovarian hormones stimulation upregulating the expression of genes involved in leiomyoma pathogenesis. This tissue model preserves extracellular matrix, cellular diversity and genetic background simulating more in-vivo-like situations. As a novelty, this platform allows encapsulation of microspheres containing drugs that can be tested on the ex vivo tumour slices. After optimizing drug release rates, microspheres would then be directly tested in animal models through local injection. Uterine leiomyoma (UL), also called fibroid or myoma, is the most commonly diagnosed tumour of the female genital tract with an incidence of 40% at the age of 35 and nearly 70-80% around the age of 50 1,2. Severe symptoms develop in 15-30% of patients being irregular, prolonged or heavy vaginal bleeding the most common manifestations frequently associated with moderate to severe anemia 1. In addition, UL may interfere with embryo implantation, complications during pregnancy and childbirth, decreasing reproductive success 3. Fibroids are the leading cause of hysterectomy with an estimated US healthcare cost of ~$21 billion annually 4. Although the etiology remains elusive, some progress has been made about the molecular mechanisms involved in tumour initiation and growth including (1) steroid hormone-dependency 2 , (2) excessive accumulation of extracellular matrix (ECM), a reservoir for growth factors, cytokines, chemokines, angiogenic and inflammatory response mediators and proteases that contribute to cell growth, differentiation and ECM turnover 5,6 and (3) alterations in driver genes such as HMGA2 (high mobility group AT-hook 2) and MED12 (mediator complex subunit 12) occurring in most of the tumours 7,8. Different cell populations are found in leiomyomas, including smooth muscle (SMC), fibroblast and stem cells 9-12 , all of them embedded in the abundant ECM. Communication between these cells seems to be critical for tumour proliferation and survival 9-11. Thus, it has been proposed that leiomyoma stem-progenitor cells devoid of sex hormonal receptors, respond to paracrine signals sent by surrounding tumour cells upon ovarian steroid stimulation, inducing self-renewal and tumour maintenance and growth 13. Furthermore, UL derived fibroblast stimulate the proliferation of leiomyoma cells and collagen type I production 6,11,14. Most studies published to date have used traditional 2D culture models of primary or immortalize...

Leiomyomas or fibroids are the most frequently diagnosed tumors of the female genital tract, and their growth seems to be steroid-hormone dependent by a yet undetermined cellular and molecular mechanism. Sexual hormones induce the secretion of growth factor peptides and the expression of their receptors, stimulating cell proliferation. One of these factors is neurotensin, and increasing evidence suggests that it can promote growth of different cancer cells. Since there are no data on neurotensin expression in normal and tumoral uterine tissue, we have analyzed the expression of NTS and NTSR1 receptor using immunohistochemistry for protein detection, in situ hybridization to detect cells expressing NTS mRNA, and RT-PCR to detect NTSR1 transcript as well as any of the alternative splice variants recently described for this receptor. We found that NTS and NTSR1 are expressed in connective cells of normal myometrium. In leiomyomas, immunoreactivity for NTS and NTSR1 receptor is colocalized in the smooth muscle cells that are also transcribing NTS. Women receiving high doses of steroids for in vitro fertilization showed tumor growth and increased immunoreactivity for neurotensin and NTSR1 receptor. Interestingly, alternative splice variants of NTSR1 receptor were detected only in tumoral tissue. These findings suggest a role of steroid hormones inducing neurotensin expression in leiomyoma smooth muscle cells. In these cells, NTS could act autocrinally through NTSR1 receptor, promoting their proliferation.

These and our previous data demonstrate that the whole tachykinin system is differentially regulated in leiomyomas. The increased expression of NK1R-Tr might stimulate leiomyoma growth in a similar way to that observed in other steroid-dependent tumors.