Heterobinuclear copper(II)‑platinum(II) complexes with oxindolimine ligands: Interactions with DNA, and inhibition of kinase and alkaline phosphatase proteins.

Two mononuclear copper(II) compounds, [Cu(isad)(HO)Cl]Cl 1 and [Cu(isah)(HO)Cl]Cl 2, and its corresponding heterobinuclear species containing also platinum(II), [CuCl(isad)Pt(NH)Cl] 3 and [CuCl(isah)Pt(NH)Cl] 4 (where isad and isah are oxindolimine ligands, (E)-3-(2-(3-aminopropylamino)ethylimino)indolin-2-one, and (E)-3-(3-amino-2-hydroxypropylimino)indolin-2-one, respectively), have been previously synthesized and characterized by different spectroscopic techniques in our laboratory. Cytotoxicity assays performed with B16F10 murine cancer cells, and MES-SA human uterine sarcoma cells, showed IC values lower or in the same order of cisplatin. Herein, in order to better elucidate their probable modes of action, possible interaction and damage to DNA, as well as their effect on the activity of crucial proteins were verified.

Immunoexpression of aromatase and estrogen receptors β in stem spermatogonia of bullfrogs indicates a role of estrogen in the seasonal spermatogonial mitotic activity.

Bullfrog stem spermatogonia, also named primordial germ cells (PGCs), show strong testosterone immunolabeling in winter, but no or weak testosterone immunoexpression in summer. Thus, the role of testosterone in these cells needs to be clarified. In this study, we proposed to evaluate whether PGCs express aromatase and estrogen receptors, and verify a possible role of estrogen in PGCs seasonal proliferation.

Primordial germ cells (spermatogonial stem cells) of bullfrogs express sex hormone-binding globulin and steroid receptors during seasonal spermatogenesis.

In vertebrate species, testosterone seems to inhibit spermatogonial differentiation and proliferation. However, this androgen can also be converted, via aromatase, into estrogen which stimulates spermatogonial differentiation and mitotic activity. During seasonal spermatogenesis of adult bullfrogs Lithobates catesbeianus, primordial germ cells (PGCs) show enhanced testosterone cytoplasm immunoexpression in winter; however, in summer, weak or no testosterone immunolabelling was observed.