Joan Villena

Ceramide-induced formation of ROS and ATP depletion trigger necrosis in lymphoid cells

In lymphocytes, Fas activation leads to both apoptosis and necrosis, whereby the latter form of cell death is linked to delayed production of endogenous ceramide and is mimicked by exogenous administration of long- and short-chain ceramides. Here molecular events associated with noncanonical necrotic cell death downstream of ceramide were investigated in A20 B lymphoma and Jurkat T cells. Cell-permeable, C6-ceramide (C6), but not dihydro-C6-ceramide (DH-C6), induced necrosis in a time- and dose-dependent fashion. Rapid formation of reactive oxygen species (ROS) within 30 min of C6 addition detected by a dihydrorhodamine fluorescence assay, as well as by electron spin resonance, was accompanied by loss of mitochondrial membrane potential. The presence of N-acetylcysteine or ROS scavengers like Tiron, but not Trolox, attenuated ceramide-induced necrosis. Alternatively, adenovirus-mediated expression of catalase in A20 cells also attenuated cell necrosis but not apoptosis. Necrotic cell death observed following C6 exposure was associated with a pronounced decrease in ATP levels and Tiron significantly delayed ATP depletion in both A20 and Jurkat cells. Thus, apoptotic and necrotic death induced by ceramide in lymphocytes occurs via distinct mechanisms. Furthermore, ceramide-induced necrotic cell death is linked here to loss of mitochondrial membrane potential, production of ROS, and intracellular ATP depletion.

Daidzein–Estrogen Interaction in the Rat Uterus and Its Effect on Human Breast Cancer Cell Growth

Sex hormone replacement therapy provides several advantages in the quality of life for climacteric women. However, estrogen-induced cell proliferation in the uterus and mammary gland increases the risk of cancer development in these organs. The lower incidence of mammary cancer in Asian women as compared with Western women has been attributed to high intake of soy isoflavones, including genistein. We have previously shown that genistein induces an estradiol-like hypertrophy of uterine cells, but does not induce cell proliferation, uterine eosinophilia, or endometrial edema. It also inhibits estradiol-induced mitosis in uterine cells and hormone-induced uterine eosinophilia and endometrial edema. Nevertheless, genistein stimulates growth of human breast cancer cells in culture; therefore, it is not an ideal estrogen for use in hormone replacement therapy (HRD). The present study investigated the effect of another soy isoflavone, daidzein (subcutaneous, 0.066 mg/kg body weight), in the same animal model, and its effect on responses induced by subsequent treatment (1 h later) with estradiol-17β (E(2); subcutaneous, 0.33 mg/kg body weight). In addition, we investigated the effects of daidzein (1 μg/mL) or E(2) on the growth of human breast cancer cells in culture. Results indicate that daidzein stimulates growth of breast cancer cells and potentiates estrogen-induced cell proliferation in the uterus. We suggest caution for the use of daidzein or formulas containing this compound in HRD. Future research strategies should be addressed in the search for new phytoestrogens that selectively inhibit cell proliferation in the uterus and breast.

Comparative study on the larvicidal activity of drimane sesquiterpenes and nordrimane compounds against Drosophila melanogaster til-til.

Natural compounds from Drimys winteri Forst and derivatives exhibited larvicidal effects against Drosophila melanogaster til-til. The most active compound was isodrimenin (4). The highest lethal concentration to the larvae of D. melanogaster was 4.5 ± 0.8 mg/L. At very low concentrations drimenol (1), confertifolin (3), and drimanol (5) displayed antifeedant and larvae growth regulatory activity. The antifeedant results of nordrimanic and drimanic compounds were better in first instar larvae. The EC50 value of polygodial (2) was 60.0 ± 4.2 mg/L; of diol 15 45.0 ± 2.8 mg/L, and of diol 17 36.9 ± 3.7 mg/L, while the new nordrimane compound 12 presented a value of 83.2 ± 3.5 mg/L.

Microwave-assisted reaction of 2,3-dichloronaphthoquinone with aminopyridines

The synthesis of pyridylaminonaphthoquinones by microwave-assisted reaction of 2,3-dichloro-1,4-naphthoquinone with aminopyridines is described. The use of microwave irradiation diminished the reaction times and improved the yields substantially in all these reactions. The compounds were tested for their cytotoxic activities against MCF-7 breast cancer cell line.

Study on the cytotoxic activity of drimane sesquiterpenes and nordrimane compounds against cancer cell lines

Twelve drimanes, including polygodial (1), isopolygodial (2), drimenol (3), confertifolin (4), and isodrimenin (5), were obtained from natural sources. Semi-synthetic derivatives 6–12 were obtained from 1 and 2, and cytotoxic activity was evaluated in vitro against cancer cell lines (HT-29, MDA-MB231, DHF, MCF-7, PC-3, DU-145, and CoN). IC50 values were determined at concentrations of 12.5–100 µM of each compound for 72 h. In addition, it was found that polygodial (1), 8, and 12 induced changes in mitochondrial membrane permeability in CoN, MCF-7, and PC-3 cells.

Antifungal study of the resinous exudate and of meroterpenoids isolated from Psoralea glandulosa (Fabaceae)

ETHNOPHARMACOLOGICAL RELEVANCE Psoralea glandulosa L. (Fabaceae) is a medicinal resinous shrub used in Chilean folk medicine as antiseptic in treatment of infections and skin diseases caused by bacteria and fungus. AIM OF THE STUDY To evaluate the in vitro antifungal activity of the resin and the active components from P. glandulosa against clinical yeast isolates. MATERIALS AND METHODS Active compounds were obtained of the resinous exudate from aerial parts of P. glandulosa. Eight species of yeast were exposed to the resin and two major compounds. Minimum inhibitory concentration (MIC(80)) was determined according to the standard broth microdilution method. RESULTS Bakuchiol and 3-hydroxy-bakuchiol demonstrated potent activity with the MIC(80) ranging from 4 to >16 and 0.125 to 16 μg/mL, respectively. The resin had some degree of antifungal activity. CONCLUSIONS The overall results provided important information for the potential application of the 3-hydroxy-bakuchiol from P. glandulosa in the therapy of serious infection and skin diseases caused by clinical yeast.

Genistein Selectively Inhibits Estrogen-Induced Cell Proliferation and Other Responses to Hormone Stimulation in the Prepubertal Rat Uterus

Sex hormone replacement therapy helps improve quality of life in climacteric women. However, estrogen-induced cell proliferation in the uterus and mammary gland increases the risk for cancer in these organs. The lower incidence of mammary cancer in Asian women than in western women has been attributed to high intake of soy isoflavones, including genistein. Our previous work in the prepubertal rat uterus model showed that genistein (0.5 mg/kg body weight subcutaneously) caused an estradiol-like hypertrophy in myometrial and uterine luminal epithelial cells and an increase in RNA content in luminal epithelium; however, it did not induce cell proliferation, uterine eosinophilia, or endometrial edema. The present study investigated, in the same animal model, the effect of genistein administration (0.5 mg/kg body weight subcutaneously) before treatment with estradiol-17β (0.33 mg/kg body weight subcutaneously) on uterine responses that were not induced by genistein. Pretreatment with this phytoestrogen completely inhibited estradiol-induced mitoses in uterine luminal epithelium, endometrial stroma, and myometrium and partially inhibited estradiol-induced uterine eosinophilia and endometrial edema. These findings indicate that genistein protects against estrogen-induced cell proliferation in the uterus and suggest that future studies should investigate the possibility of using this agent to decrease the risk for uterine cancer after hormone replacement therapy in climacteric women.

Synthesis of geranylhydroquinone derivatives with potencial cytotoxic activity

Natural geranylhydroquinone 1 and geranyl-p-methoxyphenol 2 were prepared by Electrophilic Aromatic Substitution (EAS) reactions between geraniol and 1,4-hydroquinone or p-methoxyphenol respectively, using BF3∙Et2O as a catalyst. Furthermore, natural geranylquinone 3, geranyl-1,4-dimethoxyquinone 4 and the new geranyl-4-methoxyphenyl acetate 5 were obtained by chemical transformations of 1 and 2. The compounds were evaluated for their in vitro cytotoxicity activities against cultured human cancer cells of PC-3 human prostate cancer, MCF-7 and MDA-MB-231 breast carcinoma, and Dermal Human Fibroblasts DHF. IC50 values were in the µM range.

Cytotoxic and apoptotic effects of leptocarpin, a plant-derived sesquiterpene lactone, on human cancer cell lines

Sesquiterpene lactones have attracted much attention in drug research because they present a series of biological activities such as anticancer, antifungal, anti-inflammatory, antimicrobial and antioxidant. Leptocarpin (LTC) is a sesquiterpene lactone isolated from a native Chilean plant, Leptocarpha rivularis, which has been widely used in traditional medicine by Mapuche people. Previous work has demonstrated that LTC decreases cell viability of cancer cell lines. In this contribution, we analyze the mechanism of LTC cytotoxicity on different cancer cell lines. The results show that in all cases LTC induces an apoptotic process and inhibition of NF-κB. Apoptosis has been confirmed by observing condensation of chromatin, nuclear fragmentation, release of cytochrome c into the cytosol, and increasing of caspase-3 activity. It has also been found that LTC is an effective inhibitor of NF-κB, which suggests that leptocarpin-induced cytotoxicity involves in some degree the inhibition of NF-κB signaling pathway. The concentration at which LTC inhibits NF-κB activity to the control level is similar or even lower than that found for parthenolide and others sesquiterpene lactones. These results indicate that leptocarpine is a very interesting molecule that could be considered as therapeutic agent for cancer treatment.

Psoralea glandulosa as a Potential Source of Anticancer Agents for Melanoma Treatment

With the aim of identifying novel agents with antigrowth and pro-apoptotic activity on melanoma cancer, the present study was undertaken to investigate the biological activity of the resinous exudate of aerial parts from Psoralea glandulosa, and its active components (bakuchiol (1), 3-hydroxy-bakuchiol (2) and 12-hydroxy-iso-bakuchiol (3)) against melanoma cells (A2058). In addition, the effect in cancer cells of bakuchiol acetate (4), a semi-synthetic derivative of bakuchiol, was examined. The results obtained show that the resinous exudate inhibited the growth of cancer cells with IC50 value of 10.5 μg/mL after 48 h of treatment, while, for pure compounds, the most active was the semi-synthetic compound 4. Our data also demonstrate that resin is able to induce apoptotic cell death, which could be related to an overall action of the meroterpenes present. In addition, our data seem to indicate that the apoptosis correlated to the tested products appears, at least in part, to be associated with an increase of reactive oxygen species (ROS) production. In summary, our study provides the first evidence that P. glandulosa may be considered a source of useful molecules in the development of analogues with more potent efficacy against melanoma cells.