Structure-activity relationship for Fe(III)-salen-like complexes as potent anticancer agents.

Quantitative structure activity relationship (QSAR) for the anticancer activity of Fe(III)-salen and salen-like complexes was studied. The methods of density function theory (B3LYP/LANL2DZ) were used to optimize the structures. A pool of descriptors was calculated: 1497 theoretical descriptors and quantum-chemical parameters, shielding NMR, and electronic descriptors. The study of structure and activity relationship was performed with multiple linear regression (MLR) and artificial neural network (ANN). In nonlinear method, the adaptive neuro-fuzzy inference system (ANFIS) was applied in order to choose the most effective descriptors. The ANN-ANFIS model with high statistical significance (R (2) train = 0.99, RMSE = 0.138, and Q (2) LOO = 0.82) has better capability to predict the anticancer activity of the new compounds series of this family. Based on this study, anticancer activity of this compound is mainly dependent on the geometrical parameters, position, and the nature of the substituent of salen ligand.

Enhancement of cisplatin cytotoxicity in combination with herniarin in vitro.

Combinatorial chemotherapy is a valuable route, which can be conducted by different approaches. Use of cisplatin has been approved by the U.S. Food and Drug Administration for different kinds of cancers including bladder cancer. Herniarin is a member of simple coumarins, which are a group of common secondary metabolites in plants. In this study, the enhancing effects of herniarin on cisplatin cytotoxicity were investigated. Cytotoxicity of herniarin on transitional cell carcinoma (TCC) cells was first investigated in comparison with umbelliferone, the parent compound for a large number of coumarins including herniarin, by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. In order to test the effects of herniarin on cisplatin cytotoxicity, TCC cells were also treated with various combining concentrations of herniarin and cisplatin. In these experiments same amounts of dimethyl sulfoxide were used as controls. After 24, 48 and 72 h of treatments, the effects of herniarin on cisplatin cytotoxicity were evaluated by MTT assay. The level of chromatin condensation which represents the apoptotic morphology was also investigated by 4',6-diamidino-2-phenylindole (DAPI) staining. Results indicated that unlike umbelliferone, its methoxy analog, herniarin, had no significant cytotoxicity on TCC cells. On the other hand, the combination of 80 µg/mL herniarin with 5 µg/mL cisplatin, significantly enhanced the cytotoxicity of cisplatin. Furtheremore, DAPI staining revealed that combining concentrations of herniarin and cisplatin resulted in increased chromatin condensation in comparison with controls. This study is another confirmation for bioactivity of herniarin and shows that it might be a good candidate for further experiments investigating its mechanism of action.

Human adipose-derived mesenchymal stem cells can survive and integrate into the adult rat eye following xenotransplantation.

BACKGROUND: Novel threads of discovery provide the basis for optimism for the development of a stem-cell-based strategy for the treatment of retinal blindness. Accordingly, achievement to suitable cell source with potential-to-long-term survival and appropriate differentiation can be an effective step in this direction. METHODS: After derivation of human adipose-derived mesenchymal stem cells (HAD-MSCs), they were stably transfected with a vector containing Turbo-green fluorescent protein (GFP) and JRed to be able to trace them after transplantation. Labeled HAD-MSCs were transplanted into the intact adult rat eye and their survival, integration, and migration during 6 months post-transplantation were assessed. RESULTS: The transplanted cells were traceable in the rat vitreous humor (VH) up until 90 days after transplantation, with gradual reduction in numbers, their adhesion and expansion capacity after recovery. These cells were also integrated into the ocular tissues. Nonetheless, some of the implanted cells succeeded to cross the blood-retina barrier (BRB) and accumulate in the spleen with time. CONCLUSIONS: The survival of the HAD-MSCs for a period of 90 days in VH and even longer period of up to 6 months in other eye tissues makes them a promising source to be considered in regenerative medicine of eye diseases. However, the potency of crossing the BRB by the implanted cells suggests that use of HAD-MSCs must be handled with extreme caution.

New windows to enhance direct reprogramming of somatic cells towards induced pluripotent stem cells.

Induced pluripotent stem cells are generated by direct reprogramming of somatic cells with the introduction of defined transcription factors or other means. Clinical applications of induced pluripotent stem cells are the latest of stem cell therapy approaches due to overcoming problems associated with insufficient cells from conventional sources and immune rejections. In practice, this is restricted by 4 major barriers including the use of genetic manipulations for delivering the reprogramming factors, low efficiency of this process, slow kinetics of the direct reprogramming, and potential for tumor development. Here, we review the latest achievements in improving reprogramming efficiency by alternative strategies. These alternatives mainly involve the replacement of genetic reprogramming factors with small molecules or other factors.

Cytotoxicity of vincristine on the 5637 cell line is enhanced by combination with conferone.

Bladder cancer is one of the most common cancers worldwide, with the highest incidence in industrialized countries. There are three major histological subtypes of bladder cancer: transitional cell carcinoma (TCC) (> 90%), squamous cell carcinoma (< 10%) and adenocarcinoma (1-2%). The present study was carried out to assess the effects of conferone, a sesquiterpene coumarin isolated from Ferula badrakema, on a TCC subline, 5637 cells. In order to test the effects of conferone, 5637 cells were treated with different concentrations (16, 32, 64, 128 microg/ml) of conferone. The results indicated that conferone did not have any significant cytotoxic effect on these neoplastic cells. To determine the combining effects, the cells were cultured in the presence of different concentrations of conferone (16, 32, 64, 128 microg/ ml) and vincristine (30, 40, 50 microg/ml) in combination. The morphological changes were then observed and cytotoxicity effects were studied using the MTT assay 24, 48 and 72 h following drug administration. The cells were more rounded and granulated after treatments with both drugs in comparison to vincristine only. The results of the MTT assay confirmed the morphological observations. After 48 h of combined treatment with 40 microg/ml vincristine and 16 microg/ml conferone, the cytotoxicity of vincristine was increased by 23.6%.

Phosphoenolpyruvate carboxykinase in Arabidopsis: changes in gene expression, protein and activity during vegetative and reproductive development.

The aim of this work was to investigate the occurrence of phosphoenolpyruvate carboxykinase (PEPCK) in different tissues of Arabidopsis thaliana throughout its vegetative and reproductive growth. The A. thaliana genome contains two PEPCK genes (PCK1 and PCK2), and these are predicted to generate 73,404 and 72,891 Da protein products, respectively. Both genes were transcribed in a range of tissues; however, PCK1 mRNA appeared to be more abundant and was present in a wider range of tissues. PEPCK protein was present in flowers, fruit, developing seed, germinating seed, leaves, stems and roots. Two PEPCK polypeptides, of approximately 74 and approximately 73 kDa were detected by immunoblotting, and these may arise from PCK1 and PCK2, respectively. PEPCK was abundant in cotyledons during post-germinative growth, and this is consistent with its well established role in gluconeogenesis. PEPCK was also abundant in sink tissues, such as young leaves, in developing flowers, fruit and seed. Immunohistochemistry and in situ hybridization showed that PEPCK was present in the nectaries, stigma, endocarp of the fruit wall and in tissues involved in the transfer of assimilates to the developing ovules and seeds, such as the vasculature and seed coat. The potential functions of PEPCK in A. thaliana are discussed.

The CDK inhibitor p27 enhances neural differentiation in pluripotent NTERA2 human EC cells, but does not permit differentiation of 2102Ep nullipotent human EC cells.

Embryonal carcinoma (EC) cells, the stem cells of teratocarcinomas, are the malignant counterparts of pluripotent embryonic stem (ES) cells, but commonly exhibit a reduced ability to differentiate, presumably because of continual selection for genetic changes that alter the balance between self-renewal, differentiation and apoptosis in favour of self-renewal. To explore the nature of the genetic changes that promote nullipotency, we have compared two human EC cell lines, a 'nullipotent' line, 2102Ep, and a 'pluripotent' line, NTERA2. A hybrid derived by fusion of these cells differentiates in response to retinoic acid but, unlike the parental NTERA2 line, does not form terminally differentiated neurons. This implies that the nullipotent EC cell line, 2102Ep, differs in expression of at least two functions in comparison with the NTERA2 pluripotent line, one affecting commitment to differentiation, and one affecting terminal neural differentiation. We have now investigated the possible role of the CDK inhibitor, p27kip1 (p27) in commitment and terminal differentiation. In NTERA2, but not in 2102Ep cells, retinoic acid induces up-regulation of p27 expression, suggesting that 2102Ep cells lack this capacity. However, constitutive expression of a p27 transgene does not overcome the block to differentiation in the 2102Ep parental cells; commitment to differentiation must be blocked elsewhere. On the other hand, constitutive over-expression of p27 from a transgene enhances the neural differentiation of NTERA2 cells. Our results suggest that p27 plays a role in terminal neuronal differentiation of human EC cells, but not in their initial commitment to differentiation, and that other factors, possibly Cyclin D2, specifically limit its ability to promote neural differentiation.

Specific knockdown of Oct4 and beta2-microglobulin expression by RNA interference in human embryonic stem cells and embryonic carcinoma cells.

We have used RNA interference (RNAi) to downregulate beta2-microglobulin and Oct4 in human embryonal carcinoma (hEC) cells and embryonic stem (hES) cells, demonstrating that RNAi is an effective tool for regulating specific gene activity in these human stem cells. The knockdown of Oct4 but not beta2-microglobulin expression in both EC and ES cells resulted in their differentiation, as indicated by a marked change in morphology, growth rate, and surface antigen phenotype, with respect to SSEA1, SSEA3, and TRA-1-60 expression. Expression of hCG and Gcm1 was also induced following knockdown of Oct4 expression, in both 2102Ep hEC cells and in H7 and H14 hES cells, consistent with the conclusion that, as in the mouse, Oct4 is required to maintain the undifferentiated stem cell state, and that differentiation to trophectoderm occurs in its absence. NTERA2 hEC cells also differentiated, but not to trophectoderm, suggesting their equivalence to a later stage of embryogenesis than other hEC and hES cells.

Use of fluorescent DNA-intercalating dyes in the analysis of DNA via ion-pair reversed-phase denaturing high-performance liquid chromatography.

SYBR Green 1 is an asymmetrical cyanine DNA-binding dye that provides an opportunity for increasing the sensitivity of nucleic acid detection when used in conjunction with gel electrophoresis. In this paper, we summarize the general properties and specific uses of SYBR green 1 in ion-pair reversed-phase denaturing high-performance liquid chromatography (IP DHPLC). We describe several applications for the WAVE DHPLC platform that illustrate the generic potential of such intercalating dyes in mutation detection and gene expression profiling. We show that SYBR Green 1 obviates the need to use end-labeled oligodeoxynucleotides for the sensitive detection of nucleic acids during chromatography. Moreover the incorporation of SYBR Green 1 into samples and elution buffers does not impair resolution and has no significant effect on the retention times of DNA fragments compared with dye-free DHPLC.

A role for nuclear localised proteasomes in mediating auxin action.

A number of important cellular events in animals and yeast are regulated by protein degradation, and it is becoming apparent that such regulated proteolysis is involved in many facets of plant physiology and development. We have investigated the role of protein degradation by proteasomes in plants using NtPSA1, a tobacco gene that is predominantly expressed in young developing tobacco tissues and has extensive homology to yeast and human alpha-type proteasome subunit genes. The NtPSA1 cDNA was used to complement a lethal mutation of the yeast PRC1 alpha subunit gene indicating that NtPSA1 encodes a functional proteasome subunit, and transient expression of an NtPSA1::GUS protein fusion in onion cells confirmed that the nuclear localisation signal that is present in the NtPSA1 peptide sequence is active in plant cells. Plants transformed with an antisense NtPSA1 gene had reduced levels of NtPSA1 mRNA and exhibited reduced apical dominance. In addition, these low NtPSA1 plants displayed several morphological defects associated with auxin resistance such as reduced stamen length, and showed increased tolerance to high concentrations of auxin. These results support a role for nuclear localised proteasomes in floral development and auxin responses.