Effects of Tepary bean (Phaseolus acutifolius) protease inhibitor and semipure lectin fractions on cancer cells.

Some natural and synthetic protease inhibitors (PI), such as the Bowman-Birk PI from soybean, have anticancer effects. We previously purified and characterized a Bowman-Birk-type PI from Tepary bean (Phaseolus acutifolius) seeds (TBPI). A semipure protein fraction containing this inhibitor, when tested its in vitro effect on transformed cells, showed a differential cytotoxic effect, as well as an increase in cell attachment to culture dishes. In this article we report that lectins were responsible for the cytotoxic effect previously observed, exhibiting a differential, antiproliferative effect on nontransformed cells and on different lineages of cancer cells. Although the purified TBPI lacked cytotoxicity, it was found to be responsible for the increase in cell adhesion, decreasing culture dishes' extracellular matrix degradation, leading to a decrease of the in vitro cell invasion capacity. This effect coincided with the suppression of Matrix Metalloproteinase-9 activity. These results indicate that Tepary bean seeds contain at least 2 different groups of bioactive proteins with distinct effects on cancer cells.

Local expression and distribution of growth hormone and growth hormone receptor in the chicken ovary: effects of GH on steroidogenesis in cultured follicular granulosa cells.

Preovulatory follicular development (PFD) is mainly regulated by gonadotropins (FSH, LH) and steroids, although other intraovarian factors are also involved. We analyzed the local expression of growth hormone (GH) in the hen ovary and the role that this hormone may play on the regulation of steroidogenesis in granulosa cells (GCs). Ovarian follicles from sexually mature hens were studied at different developmental stages. Both GH mRNA (by in situ hybridization) and protein (by immunohistochemistry) were expressed mainly in the GCs, and to a lesser extent in the theca cells of the follicular wall. Sequence of a GH cDNA 690-bp fragment obtained from the follicular wall was identical to that obtained from the pituitary. The growth hormone receptor (GHR) mRNA was also expressed in the follicles. Nine GH variants were observed by SDS-PAGE and Western blotting, but the main isoform showed a MW of 17 kDa, at all developmental stages. Addition of GH (0.1, 1, 10 nM) stimulated the synthesis of progesterone (P4) in primary GCs cultures in a dose-dependent manner (1.5, 2.9, 5.4 times, respectively). GH also stimulated the expression of cholesterol side-chain cleavage enzyme (cytochrome P450scc) mRNA, a rate-limiting enzyme during P4 synthesis (2.9, 4.6, 4.9 times, respectively), whereas the synthesis of 3ß-hydroxysteroid dehydrogenase (3ß-HSD) mRNA (a constitutive enzyme) was not changed. Both GH and GHR were co-expressed in GCs cultures. The locally expressed GH present in concentrated (4×, 6×, 8×) conditioned media obtained from ovarian GC cultures stimulated P4 production (1.2, 2.2, 4.4 times, respectively) in additional fresh cultured GCs, and this effect disappeared when the conditioned media were treated with antiserum against GH. These data suggest that locally produced GH may modulate follicular development through autocrine/paracrine effects in the chicken ovary.