The expression of aquaporin 1 and 5 in uterine leiomyomata in premenopausal women: a preliminary study

Importance of Water Transport in Mammalian Female Reproductive Tract

Aquaporins (AQPs) are involved in water homeostasis in tissues and are ubiquitous in the reproductive tract. AQPs are classified into classical aquaporins (AQP0, 1, 2, 4, 5, 6 and 8), aquaglycerolporins (AQP3, 7, 9, and 10) and superaquaporins (AQP11 and 12). Nine AQPs were described in the mammalian female reproductive tract. Some of their functions are influenced by sexual steroid hormones. The continuous physiological changes that occur throughout the sexual cycle, pregnancy and parturition, modify the expression of AQPs, thus creating at every moment the required water homeostasis. AQPs in the ovary regulate follicular development and ovulation. In the vagina and the cervix, AQPs are involved mainly in lubrication. In the uterus, AQPs are mostly mediated by estradiol and progesterone to prepare the endometrium for possible embryo implantation and fetal development. In the placenta, AQPs are responsible for the fluid support to the fetus to maintain fetal homeostasis that ensures correct fetal development as pregnancy goes on. This review is focused on understanding the role of AQPs in the mammalian female reproductive tract during the sexual cycle of pregnancy and parturition.

Aquaporin-1 and -5 are involved in the invasion and proliferation of soft tissue sarcomas

BACKGROUND AND AIM

Recent studies of several carcinomas have reported that aquaporin possesses novel oncogenic properties. The aim of this study was to clarify the involvement of aquaporin-1 and -5 in the proliferation, invasion and metastasis of soft tissue sarcomas.

MATERIALS AND METHODS

The expression of aquaporin-1 and -5 was immunohistochemically examined in 73 soft tissue sarcomas as well as in benign, locally aggressive soft tissue tumors, and in soft tissues of adult humans and human fetuses. The mRNA and protein expression of aquaporin-1 and -5 genes were quantified in 19 sarcoma tissues.

RESULTS

Aquaporin-1 was expressed in the tumor cells of 37 (51%) and aquaporin-5 in 29 (40%) of 73 soft tissue sarcomas. Two expression patterns were identified: a differentiation-dependent pattern, similar to their expression in adult human soft tissue and in benign soft tissue tumors, and an aggressiveness-related pattern, that is similar to their expression in the mesenchymal cells of the developing fetal limb. The latter expression pattern proved to be an independent prognostic factor for patients with soft tissue sarcoma, in which aquaporin-1 was related to the invasiveness, and aquaporin-5 to the proliferation of soft tissue sarcoma cells.

CONCLUSION

These results indicate pivotal roles for aquaporin-1 and -5 in the aggressive growth and metastatic potential of soft tissue sarcomas, suggesting that they are promising targets for the treatment of patients with intractable soft tissue sarcoma.

Aquaporin-5: from structure to function and dysfunction in cancer

Aquaporins, a highly conserved group of membrane proteins, are involved in the bidirectional transfer of water and small solutes across cell membranes taking part in many biological functions all over the human body. In view of the wide range of cancer malignancies in which aquaporin-5 (AQP5) has been detected, an increasing interest in its implication in carcinogenesis has emerged. Recent publications suggest that this isoform may enhance cancer cell proliferation, migration and survival in a variety of malignancies, with strong evidences pointing to AQP5 as a promising drug target and as a novel biomarker for cancer aggressiveness with high translational potential for therapeutics and diagnostics. This review addresses the structural and functional features of AQP5, detailing its tissue distribution and functions in human body, its expression pattern in a variety of tumors, and highlighting the underlying mechanisms involved in carcinogenesis. Finally, the actual progress of AQP5 research, implications in cancer biology and potential for cancer detection and prognosis are discussed.

Estradiol concentration and the expression of estrogen receptors in the testes of the domestic goose (Anser anser f. domestica) during the annual reproductive cycle

Seasonal fluctuations in the activity of bird testes are regulated by a complex mechanism where androgens play a key role. Until recently, the role played by estrogens in males has been significantly underestimated. However, there is growing evidence that the proper functioning of the testes is associated with optimal estradiol (E2) concentration in both the plasma and testes of many mammalian species. Estrogens are gradually emerging as very important players in hormonal regulation of reproductive processes in male mammals. Despite the previously mentioned, it should be noted that estrogenic action is limited by the availability of specific receptors--estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ). Interestingly, there is a general scarcity of information concerning the estrogen responsive system in the testes of male birds, which is of particular interest in exploring the phenomenon of seasonality of reproduction. To address this question, we have investigated for the first time the simultaneous expression of testicular ERα and ERβ genes and proteins with the accompanying plasma and testicular E2 concentrations during the annual reproductive cycle of male bird. The research model was the domestic goose (Anser anser f. domestica), a species whose annual reproductive cycle can be divided into 3 distinct phases characterized by changes in testicular activity. It has been revealed that the stable plasma E2 profile did not correspond to changing intratesticular E2 profile throughout the experiment. The expression of ERα and ERβ genes and proteins was detected in gander testes and it fluctuated on a seasonal basis with lower level in breeding and sexual reactivation stages and higher level during the nonbreeding stage. Our results demonstrated changes in testicular sensitivity to estrogens in male domestic goose during the annual reproductive cycle. The seasonal pattern of estrogen receptors (ERs) expression was analyzed against the hormonal background and a potential mechanism of ERs regulation in bird testes was proposed. The present study revealed seasonal variations in the estrogen responsive system, but further research is needed to fully explore the role of estrogens in the reproductive tract of male birds.