RKIP sensitizes prostate and breast cancer cells to drug-induced apoptosis

Cancer cells are more susceptible to chemotherapeutic agent-induced apoptosis than their normal counterparts. Although it has been demonstrated that the increased sensitivity results from deregulation of oncoproteins during cancer development (Evan, G. I., and Vousden, K. H. (2001) Nature 411, 342-348; Green, D. R., and Evan, G. I. (2002) Cancer Cell 1, 19-30), little is known about the signaling pathways leading to changes in the apoptotic threshold in cancer cells. Here we show that low RKIP expression levels in tumorigenic human prostate and breast cancer cells are rapidly induced upon chemotherapeutic drug treatment, sensitizing the cells to apoptosis. We show that the maximal RKIP expression correlates perfectly with the onset of apoptosis. In cancer cells resistant to DNA-damaging agents, treatment with the drugs does not up-regulate RKIP expression. However, ectopic expression of RKIP resensitizes DNA-damaging agent-resistant cells to undergo apoptosis. This sensitization can be reversed by up-regulation of survival pathways. Down-regulation of endogenous RKIP by expression of antisense and small interfering RNA (siRNA) confers resistance on sensitive cancer cells to anticancer drug-induced apoptosis. Our studies suggest that RKIP may represent a novel effector of signal transduction pathways leading to apoptosis and a prognostic marker of the pathogenesis of human cancer cells and tumors after treatment with clinically relevant chemotherapeutic drugs.     

Synthesis,characterization and cytotoxic activity on breast cancer cells of new half-titanocene derivatives

A series of novel titanocene-complexes has been prepared and evaluated for their growth regulatory effects in MCF7 and SkBr3 breast cancer cells. The capability of some of these compound to elicit relevant repressive effects on cancer cell growth could be taken into account towards novel pharmacological approaches in cancer therapy.     

Synergistic effect and mechanism of vitamin A and vitamin D on inducing apoptosis of prostate cancer cells

To explore the mechanism and synergistic effect of vitamin A and vitamin D in inducing apoptosis of prostate cancer cells. The cell proliferation activity was determined by MTT assay. The proportion of apoptotic cells was analyzed by FACS and fluorescence intensity. TUNEL was used to evaluate vitamin A and vitamin D’s induction of apoptosis in prostate cancer cells. The protein and mRNA expression level of Cyclin D1 and Bax were determined by real time-PCR and western blot. The results of MTT showed vitamin A and vitamin D’s inhibition on proliferation ratio in prostate cancer cells is time and concentration dependent. FACS and fluorescence intensity analysis proved that the proportion of apoptotic cells increased after vitamin A and vitamin D treatment. TUNEL showed vitamin A and vitamin D induced prostate cancer cells apoptosis. The combination of vitamin A and vitamin D markedly enhanced the expression of Bax and reduced the expression of Cyclin D1 by real time-PCR and western blot assay. In conclusion, vitamin A and vitamin D could synergistically induce apoptosis in prostate cancer cells.     

Epidermal growth factor protects prostate cancer cells from apoptosis by inducing BAD phosphorylation via redundant signaling pathways

Protection from apoptosis by receptor tyrosine kinases, resistant to the inhibition of phosphatidylinositol 3 '-kinase/Akt and Ras/MEK pathways, has been reported in several cell types, including fibroblasts and epithelial prostate cancer cells; however, mechanisms of this effect were not clear. Here we report that in prostate cancer cells, epidermal growth factor activates two antiapoptotic signaling pathways that impinge on the proapoptotic protein BAD. One signaling cascade operates via the Ras/MEK module and induces BAD phosphorylation on Ser112. Another pathway predominantly relies on Rac/PAK1 signaling that leads to BAD phosphorylation on Ser136. Each of these two pathways is sufficient to protect cells from apoptosis, and therefore both have to be inhibited simultaneously to block epidermal growth factor-dependent survival. Redundancy of antiapoptotic signaling pathways should be considered when therapies targeting antiapoptotic mechanisms are designed.     

Design, synthesis and vasodilative activity of tanshinone IIA derivatives

A new series of tanshinone IIA (DIIA) derivatives were synthesized through the reaction of brominated tanshinone IIA (1-Br DIIA) and aromatic acids in the presence of K(2)CO(3). Twenty compounds were synthesized, and all of them were novel. Vasodilative activities for synthesized compounds were valuated in vitro on the contractile response of vascular thoracic aorta smooth muscle from Wistar rats. The results showed that most compounds exhibited a concentration-dependent inhibition on the contractile response of norepinephrine. Four prepared compounds, 4, 5, 8 and 13 revealed relatively remarkable vasodilative activity.     

Antiproliferative activity and apoptosis inducing effects of nitric oxide donating derivatives of evodiamine

The first series of nitric oxide donating derivatives of evodiamine were designed and prepared. NO releasing ability of all target derivatives was evaluated in BGC-823, Bel-7402 and L-02 cells. The cytotoxicity was evaluated against three human tumor cell lines (Bel-7402, A549 and BGC-823) and normal human liver cells L-02. The nitrate derivatives 11a and 11b only exhibited moderate activity and furoxan-based derivatives 13a–c, 14a and 14b showed promising activity. 13c showed good cytotoxic selectivity between tumor and normal liver cells and was further investigated for its apoptotic properties on human hepatocarcinoma Bel-7402 cells. The molecular mode of action revealed that 13c caused cell-cycle arrest at S phase and induced apoptosis in Bel-7402 cells through mitochondria-related caspase-dependent pathways.     

Protein analysis through Western blot of cells excised individually from human brain and muscle tissue

Comparing protein levels from single cells in tissue has not been achieved through Western blot. Laser capture microdissection allows for the ability to excise single cells from sectioned tissue and compile an aggregate of cells in lysis buffer. In this study we analyzed proteins from cells excised individually from brain and muscle tissue through Western blot. After we excised individual neurons from the substantia nigra of the brain, the accumulated surface area of the individual cells was 120,000, 24,000, 360,000, 480,000, 600,000 μm2. We used an optimized Western blot protocol to probe for tyrosine hydroxylase in this cell pool. We also took 360,000 μm2 of astrocytes (1700 cells) and analyzed the specificity of the method. In muscle we were able to analyze the proteins of the five complexes of the electron transport chain through Western blot from 200 human cells. With this method, we demonstrate the ability to compare cell-specific protein levels in the brain and muscle and describe for the first time how to visualize proteins through Western blot from cells captured individually.     

Modification of alternative splicing of Bcl-x pre-mRNA in prostate and breast cancer cells. analysis of apoptosis and cell death

There is ample evidence that deregulation of apoptosis results in the development, progression, and/or maintenance of cancer. Since many apoptotic regulatory genes (e.g. bcl-x) code for alternatively spliced protein variants with opposing functions, the manipulation of alternative splicing presents a unique way of regulating the apoptotic response. Here we have targeted oligonucleotides antisense to the 5'-splice site of bcl-x(L), an anti-apoptotic gene that is overexpressed in various cancers, and shifted the splicing pattern of Bcl-x pre-mRNA from Bcl-x(L) to Bcl-x(S), a pro-apoptotic splice variant. This approach induced significant apoptosis in PC-3 prostate cancer cells. In contrast, the same oligonucleotide treatment elicited a much weaker apoptotic response in MCF-7 breast cancer cells. Moreover, although the shift in Bcl-x pre-mRNA splicing inhibited colony formation in both cell lines, this effect was much less pronounced in MCF-7 cells. These differences in responses to oligonucleotide treatment were analyzed in the context of expression of Bcl-x(L), Bcl-x(S), and Bcl-2 proteins. The results indicate that despite the presence of Bcl-x pre-mRNA in a number of cell types, the effects of modification of its splicing by antisense oligonucleotides vary depending on the expression profile of the treated cells.     

Steroidal aromatase inhibitors inhibit growth of hormone-dependent breast cancer cells by inducing cell cycle arrest and apoptosis

Different hormonal therapies are used for estrogen receptor positive (ER⁺) breast cancers, being the third-generation of aromatase inhibitors (AIs), an effective alternative to the classical tamoxifen. AIs inhibit the enzyme aromatase, which is responsible for catalyzing the conversion of androgens to estrogens. In this study, it was evaluated the effects of several steroidal AIs, namely 3β-hydroxyandrost-4-en-17-one (1), androst-4-en-17-one (12), 4α,5α-epoxyandrostan-17-one (13a) and 5α-androst-2-en-17-one (16), on cell proliferation, cell cycle progression and cell death in an ER⁺ aromatase-overexpressing human breast cancer cell line (MCF-7aro). All AIs induced a decrease in cell proliferation and these anti-proliferative effects were due to a disruption in cell cycle progression and cell death, by apoptosis. AIs 1 and 16 caused cell cycle arrest in G₀/G₁, while AIs 12 and 13a induced an arrest in G₂/M. Moreover, it was observed that these AIs induced apoptosis by different pathways, since AIs 1, 12 and 13a activated the apoptotic mitochondrial pathway, while AI 16 induced apoptosis through activation of caspase-8. These results are important for the elucidation of the cellular effects of steroidal AIs on breast cancer cells and will also highlight the importance of AIs as inducers of apoptosis in hormone-dependent breast cancers.     

Caspase信号通路在双歧杆菌脂磷壁酸诱导结肠癌细胞凋亡中的作用

目的探讨Caspase信号通路在双歧杆菌脂磷壁酸（LTA）诱导结肠癌细胞凋亡中的作用。方法RT-PCR检测经双歧杆菌LTA处理后,结肠癌Lovo细胞中MyD88和FADD mRNA的表达变化;AnnexinV检测经Caspase通用抑制剂（Z-Val-Ala-Asp-FMK）预先处理后,双歧杆菌LTA诱导结肠癌Lovo细胞凋亡率的变化;荧光法检测经双歧杆菌LTA处理后,Lovo细胞中Caspase-8活性的变化。结果经双歧杆菌LTA处理后,Lovo细胞中MyD88的mRNA表达明显升高（P〈0．05）,而FADD信号分子的mRNA表达无明显变化;双歧杆菌LTA能够增强Lovo细胞中Caspase-8的活性（P〈0．05）,且其诱导Lovo细胞凋亡的作用能够被Caspase抑制剂所抑制（P〈0．05）。结论MyD88信号分子在双歧杆菌LTA诱导Lovo细胞凋亡中可能起着承接上游分子TLRs与下游信号分子FADD的作用;而Caspase信号通路可能是双歧杆菌LTA诱导结肠癌Lovo细胞凋亡的主要信号传导途径。     

Vulpinic acid as a natural compound inhibits the proliferation of metastatic prostate cancer cells by inducing apoptosis

Molecular Biology Reports - Lichen secondary metabolites have drawn considerable attention in recent years due to the limitations of current treatment options. Vulpinic acid (VA) obtained from...     

Resveratrol derivatives increase cytosolic calcium by inhibiting plasma membrane ATPase and inducing calcium release from the endoplasmic reticulum in prostate cancer cells

Resveratrol (RES) is a putative chemotherapeutic naturally found in grapes, peanuts, and Japanese knotweed. Previous studies demonstrate that RES modulates calcium signaling as part of its chemotherapeutic activity. In this study, we determined the chemotherapeutic activity of three RES esters that have been modified at the 4’ hydroxyl by the addition of pivalate, butyrate, and isobutyrate. All of the RES derivatives disrupted the calcium signaling in prostate cancer cells more than the parent compound, RES. Further, we demonstrate that the RES derivatives may disrupt the calcium homeostasis by activating calcium release from the endoplasmic reticulum and inhibiting plasma membrane Ca²⁺-ATPase. The pivalated and butyrated RES derivatives decreased cell viability significantly more than RES. Because pivalated and butyrated RES are more effective than RES at targeting calcium signaling pathways, pivalated and butyrated RES may serve as more effective chemotherapeutics.     

Effect of diallyl trisulfide derivatives on the induction of apoptosis in human prostate cancer PC-3 cells

The effects of five derivatives of diallyl trisulfide (DATS) were investigated on apoptosis in prostate cancer PC-3 cells, including dibutenyl trisulfide (DBTS), bis(2-methylallyl) trisulfide (2-M-DATS), dipentenyl trisulfide (DPTS), bis(3-methylbut-2-enyl) trisulfide (3-M-DBTS), and dihexenyl trisulfide (DHTS). Our present study demonstrated that DATS derivatives can suppress proliferation of PC-3 cells in a dose- and time-dependent manner, and that a change in the DATS structure could have an impact on its biological activity in the following order: 2-M-DATS > DBTS ≈ DPTS ≈ DATS > 3-M-DBTS ≈ DHTS. Typical apoptotic nuclei were shown by Hoechst 33342 staining with 80 μM concentrations of DATS derivatives for 24 h. And flow cytometric analysis and DNA fragmentation assay also demonstrated that DATS derivatives induced apoptosis in PC-3 cells. Meanwhile, experimental results showed that DBTS, 2-M-DATS, and DPTS cause G2-M phase cell cycle arrest. Furthermore, a series of apoptosis-associated features were observed, which include a notable decrease in the expression of procaspases-3, up-regulation of pro-apoptotic proteins Bax expression, and down-regulation of anti-apoptotic proteins Bcl-2 expression in PC-3 cells. All of the evidences above indicate that DATS derivatives suppressed proliferation of PC-3 cells which was associated with the induction of apoptosis regulated by Bax/Bcl-2.     

Cytotoxicity activity of L-proline analogues of anthraquinone-2-carboxylic acid in breast cancer MCF-7 cells

Although prolidase [E.C.3.4.13.9] is found in normal cells, substantially increased levels are found in some neoplastic tissues. Prolidase evokes the ability to hydrolyse the imido-bond of various low molecular weight compounds coupled to L-proline. The synthesis of three proline analogues of anthraquinone-2-carboxylic acid (1-3) has been performed. Treatment of these prodrugs with prolidase generated L-proline and the free drug, demonstrating their substrate susceptibility prolidase. The concentrations of 1, 2 and 3 needed to inhibit [1H]thymidine incorporation into DNA by 50% (IC50) in breast cancer MCF-7 cells were found to be 185 +/- 5 microM, 107 +/- 6 microM and 87 +/- 6 microM, respectively, suggesting a lower cytotoxic potency of these compounds compared to Hoechst 33228 (IC50 = 55 +/- 6 microM).     

Essential oil analysis and antimicrobial activity of eight Stachys species from Greece

The volatile composition of eight Stachys species has been studied. The investigated taxa were St. alopecuros (L.) Bentham., St. scardica (Griseb.) Hayek, St. cretica L. ssp. cretica, St. germanica L. ssp. heldreichii (Boiss.) Hayek, St. recta L., St. spinulosa L., St. euboica Rech. and St. menthifolia Vis., growing wild in Greece. The essential oils were obtained by hydrodistillation in a modified Clevenger-type apparatus, and their analyses were performed by GC and GC-MS. Identification of the substances was made by comparison of mass spectra and retention indices with literature records. Sesquiterpene hydrocarbons were shown to be the main group of constituents of all taxa. Furthermore, the obtained essential oils were tested against the following six bacteria: Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 35210), Bacillus subtilis (ATCC 10907), Bacillus cereus (clinical isolates), Micrococcus flavus (ATCC 10240), Staphylococcus epidermidis (ATCC 2228), as well as against the following five fungi: Aspergillus niger (ATCC 6275), Penicillium ochrochloron (ATCC 9112), Epidermophyton floccosum (clinical isolates), Candida albicans (clinical isolates) and Trichophyton mentagrophytes (clinical isolates). The tested essential oils showed better activity against bacterial species than against fungi. Pseudomonas aeruginosa was the most resistant strain, as none of the essential oils was active against this strain. The essential oil of St. scardica has been proven most active against both bacteria and fungi.     

Bone morphogenetic protein-9 induces apoptosis in prostate cancer cells, the role of prostate apoptosis response-4

Bone morphogenetic proteins (BMP) have been implicated in the development of bone metastases in prostate cancer. In this study, we investigated the role which BMP-9 played in prostate cancer and found that the expression of BMP-9 was decreased or absent in prostate cancer, particularly in the foci of higher grade disease. We further investigated the influence of BMP-9 on the biological behaviors of prostate cancer cells. The forced overexpression of BMP-9 prevented the in vitro growth, cell-matrix adhesion, invasion, and migration of prostate cancer cells. We also elucidated that BMP-9 induced apoptosis in PC-3 cells through the up-regulation of prostate apoptosis response-4. Among the receptors which have been implicated in the signaling of BMP-9, BMPR-IB and BMPR-II have also been implicated in the development and progression of prostate cancer. Knockdown of BMPR-IB or BMPR-II using respective hammerhead ribozyme transgenes could promote cell growth in vitro. We also found that BMPR-II is indispensable for the Smad-dependent signal transduction by BMP-9 in PC-3 cells, in which Smad-1 was phosphorylated and translocated from the cytoplasm into the nuclei. Taken together, BMP-9 inhibits the growth of prostate cancer cells due to the induced apoptosis, which is related to an up-regulation of prostate apoptosis response-4 through a Smad-dependent pathway. BMP-9 could also prevent the migration and invasiveness of prostate cancer. This suggests that BMP-9 may function as a tumor suppressor and apoptosis regulator in prostate cancer.