Cell cycle hormonal effects

Although there is evidence that hormones play a role in the control of the cell cycle, this control may be indirect, i.e., the hormones may play a permissive role in division or they may influence the cell cycle through effects on expansion or metabolism. It is curious, however, that cells arrested experimentally normally arrest in either or G2 and that gibberellin and cytokinin are important for progression from G to S and G2 to M, respectively. Thus the apparent principal control periods of the cell cycle are those most noticeably responsive to hormones a relationship probably more than coincidental. 

Wang, A. and Zhang L. 2007. Effect of lycopene on proliferation and cell cycle of hormone refractory prostate cancer PC-3 cell line. Wei Sheng Yan Jiu 36 575-578. 

It has been argued that the glycoprotein composition of the cell surface is a determinant in cell behavior,146,149 and it is clear that many properties of cells may be affected by the action of glycosidases on cell-surface glycoproteins. In this respect, changes in their electrophoretic mobility, in the regulation of the cell cycle, and in cell-cell interactions, and the effects on lymphocyte stimulation of cells, their immunogenicity, their interaction with hormones, and their onco-... 

Like all steroids, brassinosteroids derive from a single common precursor mevalonic acid. Some phytohormones are synthesized totally or in part via the isoprenoid pathway, such as absdsic acid, gibberellins and cytokinins. The importance of this biosynthetic pathway in processes involved with cell cycle regulation and tumorigenesis in mammals is well documented. Having in mind the similarities between certain regulatory systems in plants and animals the question arose whether brassinosteroids as putative plant steroid hormones would show a specific effect on plant tumor cells. 

Traditional chemotherapeutic strategies, on the assumption that the majority of the cells within tumor are actively proliferating, have used a variety of drugs and hormonal agents that interfere with the basic cellular machinery (e.g., DNA synthesis and replication, cell cycle, and cytoskeleton) [57]. However, because cancer cells share many properties with their normal counterparts, the serious, sometimes life-threatening, side effects that arise from toxicities to sensitive normal cells limit the efficacy of cytotoxic chemotherapy [58]. Improved understanding of the molecular alterations present in the cancer cells has enabled the... 

The question of whether the effects of altered thyroid states on cell proliferation in the EGL are direct or indirect still must be answered. In favor of a direct effect is our finding that excess thyroxine affects the length of the cell cycle by shortening G2. This is the phase of the cycle which is involved in the decision to differentiate or complete another round of proliferation (Fox and Pardee, 1971). Moreover, it is this same part of the cycle which is shortened when thyroid hormones are presented to cell lines in vitro, where effects are presumably direct (Burki and Tobias, 1970 Defesi and Surks, 1981 Defesi et al., 1985). 

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