Prostate cancer has its highest incidence in the USA and is becoming a major concern in Asian countries. Bufadienolides are extracts of toxic glands from toads and are used as anticancer agents, mainly on leukemia cells. In the present study, the antiproliferative and apoptotic mechanisms of bufalin and cinobufagin on prostate cancer cells were investigated. Proliferation of LNCaP, DU145, and PC3 cells was measured by 3-(4,5-dimethylthiazol-2-yle)-2,5-diphenyltetrazolium bromide assay and the doubling time (tD) was calculated. Bufalin and cinobufagin caused changes in the tD of three prostate cancer cell lines, which were more significant than that of human mesangial cells. In addition, bufadienolides induced prostate cancer cell apoptosis more significantly than that in breast epithelial cell lines. After treatment, the caspase-3 activity and protein expression of caspase-3, -8, and -9 were elevated. The expression of other apoptotic modulators, including mitochondrial Bax and cytosolic cytochrome c, were also increased. However, expression of p53 was only enhanced in LNCaP P rostate cancer is currently showing its highest incidence for decades, and is the second-leading cause of cancer death among men in the USA.(1) It has been estimated that 186 320 new cases of prostate cancer will be diagnosed and that 28 660 deaths attributed to prostate cancer will occur in the USA in 2008.(2) In addition, the mortality of prostate cancer has also increased in Asian countries during the past decade. An assay for prostate-specific antigen has raised the early detection level of prostate cancer, which is curable by surgical and radiation therapies. Androgen ablation is the most common treatment for metastatic prostate cancer; however, 20-30% patients with prostate cancer experience recurrent disease.(3,4) Therefore, searching for chemoprevention or chemical controls for prostate cancer has become a crucial concern.Bufalin and cinobufagin, the major digoxin-like components of Chan-Su extracts from the venom of Bufo bufo gargarizan, have been reported as Na + -K + -ATPase inhibitors that result in elevation of the intracellular calcium concentration. (5,6) On the basis of this mechanism, bufalin and cinobufagin increase vasoconstriction, and have long been used as a treatment for heart failure by Chinese medicine in Asian countries. Disruption of intracellular calcium homeostasis induces apoptosis in diverse cell types.(7) Our previous results have illustrated that bufalin and cinobufagin are able to induce elevated calcium concentration and cell apoptosis in prostate cancer cells, but the detailed mechanism of this remains unclear.(8) Bufalin is also known as a topoisomerase II inhibitor. Topoisomerase II is a nuclear enzyme that relaxes supercoiled DNA at the time of DNA replication. Its inhibitors result in protein-linked DNA double-strand breaks. (9) Some of the topoisomerase poisons, such as etoposide and adriamycin, are efficient and widely prescribed anticancer drugs. (10) According to the mechanism described above, bu...

Progesterone is an endogenous immunomodulator, and can suppress T-cell activation during pregnancy. When analyzed under a genome time scale, the classic steroid receptor pathway does not have any effect on ion fluxes. Therefore, the aim of this study was to investigate whether the non-genomic effects on ion fluxes by progesterone could immunosuppress phytohemagglutinin (PHA)-induced human peripheral T-cell activation. The new findings indicated that, first, only progesterone stimulated both [Ca2+]i elevation and pHi decrease; in contrast, estradiol or testosterone stimulated [Ca2+]i elevation and hydrocortisone or dexamethasone stimulated pHi decrease. Secondly, the [Ca2+]i increase by progesterone was dependent on Ca2+ influx, and the acidification was blocked by Na+/H+ exchange (NHE) inhibitor, 3-methylsulphonyl-4-piperidinobenzoyl, guanidine hydrochloride (HOE-694) but not by 5-(N,N-dimethyl)-amiloride (DMA). Thirdly, progesterone blocked phorbol 12-myristate 13-acetate (PMA) or PHA-induced alkalinization, but PHA did not prevent progesterone-induced acidification. Fourthly, progesterone did not induce T-cell proliferation; however, co-stimulation progesterone with PHA was able to suppress PHA-induced IL-2 or IL-4 secretion and proliferation. When progesterone was applied 72 h after PHA stimulation, progesterone could suppress PHA-induced T-cell proliferation. Finally, immobilization of progesterone by conjugation to a large carrier molecule (BSA) also stimulated a rapid [Ca2+]i elevation, pHi decrease, and suppressed PHA-induced proliferation. These results suggested that the non-genomic effects of progesterone, especially acidification, are exerted via plasma membrane sites and suppress the genomic responses to PHA. Progesterone might act directly through membrane specific nonclassical steroid receptors to cause immunomodulation and suppression of T-cell activation during pregnancy.

Background: Although the eradication of Helicobacter pylori infection benefits patients with gastric or duodenal ulcers, the value of eradicating the infection in the patients with functional dyspepsia (FD) remains controversial. Aims: To determine whether eradicating H. pylori can prevent the subsequent development of ulcers or relieve the symptoms of functional dyspepsia patients. Methods: In a double‐blind, placebo‐controlled trial, 161 patients infected with H. pylori who had functional dyspepsia were randomly assigned to 7 days of treatment with a lansoprazole‐based triple therapy or placebo and then followed for 1 year. The main outcome measures were the development of peptic ulcers and the resolution of symptoms. Results: H. pylori was eradicated in 63 out of 81 patients (78%) in the treatment group and none of the 80 patients (0%) in the placebo group. During the follow‐up period, two patients in the treatment group and six patients in the placebo group developed peptic ulcers at repeat endoscopy (2.5% vs. 7.5%; 95% CI: –12 to 2). The reduction in ulcer rates was statistically significant in the ‘ulcer‐like’ sub‐group (0% vs. 16.7%; 95% CI: –32 to –2), but not in the ‘dysmotility‐like’ and ‘unclassifiable’ sub‐groups. Regarding symptom response, the resolution rates of symptoms were similar between the treatment and placebo groups (58.0% vs. 55.0%, 95% CI: –12 to 18). Additionally, no significant differences existed in the symptom responses between the treatment and control arms in each of the dyspepsia sub‐groups. Conclusions: Eradicating H. pylori can prevent the subsequent development of peptic ulcers in the patients with ‘ulcer‐like’ functional dyspepsia. However, this approach does not significantly reduce the symptoms of functional dyspepsia patients.

RU486 is antagonistic to the rapid mPR-mediated non-genomic responses, but is synergistic with progesterone with respect to the inhibition of PHA-induced cell proliferation. Our findings shine new light on RU486's clinical application and how this relates to the non-genomic rapid physiological responses caused by progesterone.

Progesterone is an endogenous immunomodulator and can suppress T-cell activation during pregnancy. We have previously shown that the non-genomic effects of progesterone, especially acidification, are exerted via plasma membrane sites and suppress cellular genomic responses to mitogens. This study aimed to show that acidification is due to a non-genomic inhibition of Na(+)/H(+)-exchange 1 (NHE1) by progesterone and correlate this with immunosuppressive phytohemagglutinin (PHA)-induced T-cell proliferation. The presence of amiloride-sensitive NHE 1 was identified in T cells. The activity of NHE1 was inhibited by progesterone but not by 20alpha-hydroxyprogesterone (20alpha-OHP). Furthermore, 20alpha-OHP was able to compete with progesterone and release the inhibitory effect on the NHE1. The inhibition of NHE1 activity by progesterone-BSA demonstrated non-genomic action via plasma membrane sites. Finally, co-stimulation with PHA and progesterone or amiloride, (5-(N, N-dimethyl)-amiloride, DMA), inhibited PHA-induced T-cell proliferation, but this inhibition did not occur with 20alpha-OHP and PHA co-stimulation. However, when DMA was applied 72 h after PHA stimulation, it was able to suppress PHA-induced T-cell proliferation. This is the first study to show that progesterone causes a rapid non-genomic inhibition of plasma membrane NHE1 activity in T cells within minutes which is released by 20alpha-OHP. The inhibition of NHE1 leads to immunosuppressive T-cell proliferation and suggests that progesterone might exert a major rapid non-genomic suppressive effect on NHE1 activity at the maternal-fetal interface in vivo and that 20alpha-OHP may possibly be able to quickly release the suppression when T cells circulated away from the interface.