Apoptosis in the Human Female Reproductive Tract

Abstract

Throughout fetal and adult life, the balance of cell proliferation and cell death determines the size of cell populations in tissues throughout the body. Apoptosis, or programmed cell death, is the physiologic process of cell deletion. Cell death is critical in morphogenesis in the embryo and fetus as well as in maintaining tissue homeostasis in the adult. Throughout the menstrual cycle, cell death and renewal occur in the female reproductive tract in a highly regulated sequence. The process of follicular atresia and the cyclic shedding of the endometrium involve the process of apoptosis. In pathologic states, resistance to cell death by apoptosis may play a fundamental role in tumorigenesis. Because apoptosis is such a fundamental biologic process in a variety of physiologic and pathologic states, many unique to the female reproductive tract, it is imperative that clinicians be conversant with the rapidly expanding information in this area. Although apoptotic cell death has been recognized histologically for over 20 years (1), the molecular mechanisms that regulate apoptosis have only recently begun to be elucidated. The identification of some of these regulators, such as the p53 gene, has improved our understanding of the mechanisms of tumor response to chemotherapy. This review will summarize our current knowledge of the mechanisms of apoptosis in the ovary and endometrium, and in the normal development and malignant transformation of the breast.

Effect ofChlamydia trachomatisInfection and Subsequent Tumor Necrosis Factor Alpha Secretion on Apoptosis in the Murine Genital Tract

“…shown for shedding of apoptotic cells during menstruation (44). In this respect, shedding of apoptotic cells may be a general phenomenon provoked by infection with different Chlamydia species and strains, since it had previously been reported that dying infected cells with a condensed nucleus are released from the cervical epithelium of guinea pigs infected with the GPIC strain of C. psittaci (43).…”

Cyr61 Suppresses Growth of Human Endometrial Cancer Cells

“…To maintain equilibrium between proliferation and death of cells is vital for many biological processes, especially in reproductive tissues such as the mammary gland, ovary, and uterus (32,33). Defects in this process predispose the tissue to a variety of disorders including cancer.…”

Role of Lipid Peroxidation in the Epidemiology and Prevention of Breast Cancer

“…The position of the apoptotic peak at the end of the luteal phase is important because numerous rodent, mostly, and human studies have shown that lipid peroxidation/ROS significantly increases at this time and this increase is a trigger for luteal regression and luteolysis and also decreases progesterone production in luteal cells (95)(96)(97)(98)(99)(100)(101)(102)(103)(104)(105)(106)(107)(108). In addition, antioxidant and antiapoptotic Bcl-2 protein levels also decline sharply in the late luteal phase as the incidence of apoptosis increases (245). In another study, the status of the normal mammary epithelium was summarized as a balance between factors that were proapoptotic, represented by Bax, or antiapoptotic, represented by Bcl-2, Mcl-1, and Bcl-x (246).…”