OsRab5a encodes a Rab5 protein in rice, which belongs to the Rab family of small GTP-binding protein superfamily. Transgenic plants with POsrab5a::beta-glucuronidase (GUS) gene indicate that OsRab5a is expressed in callus, root, stem, leaf, root base and spikelet (Figs.1, 2H-1). Using the transgenic Arabidopsis with fused gene of GFP::OsRab5a and GFP::OsRab5aCA and by using FM4-64 (the lipophilic styryl dye) staining, we have demonstrated that OsRab5a is involved in vesicular transport and GFP-OsRab5a is localized on the plasma membrane and early endosomes (Fig.2A-C), while GFP-OsRab5aCA is localized in the cell membrane (Fig.2D-F). The reduction of expression of OsRab5a in callus RNA interference, however, led to the lethality of callus during differentiation (Fig.3D-F). The expression of OsRab5a was upregulated slightly by exogenous cytokinin (Fig.4), and was higher in the differentiation medium than that in selection medium (Fig.3G-I). These results suggest that OsRab5a plays an important role in callus differentiation probably through mediating hormone signal transduction.

The complexation and sequestration of heavy metal ions (e.g. Cd) by the cysteine-rich polypeptides known as phytochelatins (PC) are thought to confer heavy metal hyperaccumulation and tolerance in some plant species. PC is synthesized enzymatically from glutathione. The tripeptide glutathione is a product of primary sulfur metabolism. A variety of enzymes or proteins are involved in sulfur assimilation including sulfate transporters (STs), ATP sulfurylase (ATPS), APS reductase (APSR), sulfite reductase (SiR), glutathione synthetase (GS) and phytochelatin synthesis (PCS). These enzymes or proteins are upstream-regulated by Cd at either the metabolic or the genetic level under metal stress. Increasing evidence shows that enhancement of sulfate uptake and reduction occurs with the production of PC in plants under heavy metal stress. In this article, the key aspects of our recent understanding of regulatory mechanisms involved in the relation between the sulfate assimilation and phytochelatin synthesis are described.

Cadmium (Cd) is a strongly phytotoxic heavy metal, which inhibits plant growth and even leads to plant death. The main symptoms of Cd(2+) toxicity to plants are stunting and chlorosis. Plant has developed some functions for Cd(2+) tolerance, which include cell wall binding, chelation with phytochelatins (PCs), compartmentation of Cd(2+) in vacuole, and enrichment in leaf trichomes. However, Cd(2+) tolerance in plant is more likely involved in an integrated network of multiple response processes than several isolated functions cited above. In the network, the processes of sulfur metabolism, antioxidative response, and Cd(2+) transport across plasma and vacuole membrane in plant are closely related with Cd(2+) tolerance in plant. The processes of sulfur uptake, assimilation and sequential sulfur metabolism in plant respond to Cd(2+) stress. The expression of sulfur transporters with varied affinity was changed in different ways under Cd(2+) stress, and the high expression of ATP sulfurylase (APS) and adenosine 5' phosphosulfate reductase (APR), which may help to keep the supply of S(2-) for cysteine (Cys) synthesis. The efficiency of Cys synthesis may function in Cd(2+) detoxification, and the up-regulated expression of Ser acetyltransferase (SAT) and O-acetyl-ser (thiol)-lyase (OASTL) has been found in some Cd(2+) treated plants. Reduced glutathione (GSH) is an important antioxidant and the precursor of PCs, glutamylcysteine synthetase (GCS) and glutathione synthetase (GS) catalyze GSH synthesis from Cys, overexpression of the two enzymes can improve Cd(2+) tolerance in plant. PCs are more important Cd(2+) chelators than metallothioneins (MTs) in plants, and the expression of phytochelatin synthase (PCS) responds to Cd(2+) stress. Plant antioxidative system also contributes to Cd(2+) tolerance. The antioxidative response to Cd(2+)-induced oxidative stress varies in different plants and tissues and is also Cd(2+) concentration dependent, and the Cd hyperaccumulator plants show strong tolerance to oxidative stress. Some genes encoded metal transporters with Cd(2+) substrate specificity at plasma and vacuole membranes, which have been isolated and characterized in recent years. These genes play critical roles in Cd(2+) translocation, allocation, and compartmentation in plants. Despite the great progresses made in the field in recent years, there are still some issues which need further exploration, such as the detail of signal transduction and the responses of gene regulation to Cd(2+), the rhizosphere activation and root adsorption to soil Cd(2+), Cd(2+) trafficking in xylem and phloem, Cd(2+) translocation to fruit and seed, and the possible presence of a high-affinity Cd(2+) transporter in Cd hyperaccumulators.

To explore the potential effects of anti-VEGF hairpin ribozyme gene to gene expression profiles in leukemia cell line K562.

Among the 20000 independent Arabidopsis activation tagging lines, we screened a novel mutant with high-salinity and drought tolerance, namely sdt1 (high-salinity and drought tolerant 1). sdt1 kept normal growth under drought stress by consecutively withholding water for 26d, while all the wild type wilted to death. Furthermore, the same result was repeated under high-salinity stress when sdtl and wild type were treated with 150 mmol/L NaCl. Seeds germination test on the medium indicated that the response of sdt1 to endogenous or exogenous ABA was reduced as compared with wild type. Under drought stress conditions the rates of water loss of sdt1 rosette leaves were significantly lower than that of wild type. Southern hybridization of sdt1 and the result of high-salinity tolerance genetic analysis showed that two copies of T-DNA were inserted into the two linking sites by shoulder to shoulder.

To observe if ER alpha gene can be induced by 5-aza-CdR in ER alpha negative human breast cancer cell lines (MDA-MB-231 and MDA-MB-435) and the synergistic inhibitory effects of 5-aza-CdR and Tamoxifen on these two cell lines in vitro.

To further study the impact of interferon-alpha (IFN-alpha) on thymidine phosphorylase (TP) expression and angiogenesis.

To investigate the mechanism of proliferation inhibition and apoptosis of K562 leukemia cells by lithium chloride (LiCl), after K562 cells were treated with LiCl (30 mmol/L) cell cycle was examined by flow cytometry (FCM) and the expression of bcr/abl fusion gene mRNA was evaluated by RT-PCR. The intracellular Li(+) concentrations of K562 cells were determined at different time after treated with 30 mmol/L LiCl and the effects of TTX and FSK on intracellular Li(+) concentrations of K562 cells were also detected by atomic absorption spectrometry. The effects of TTX and FSK on LiCl-induced growth inhibition of K562 cells were determined by cell counting in liquid culture. The results showed that LiCl (30 mmol/L) caused a sustained arrest in G(2)/M cell cycle and down-regulated the bcr/abl mRNA expression in K562 cells, the intracellular Li(+) concentration of K562 cells increased at 30 minutes after treated with 30 mmol/L LiCl and reached apex at 2 hours, thereafter, gradually decreased and balanced at 4 hours after the treatment. If either Na(+) channel was pre-blocked with TTX or K(+) channel was pre-blocked with FSK, the intracellular Li(+) concentrations of K562 cells treated with 30 mmol/L LiCl were higher than that in the cells just treated with LiCl without pre-blocking. Furthermore, after pre-blocking either Na(+) channel with TTX or K(+) channel with FSK, the inhibition rate of K562 cell growth by 30 mmol/L LiCl could be increased. It is concluded that the mechanism of proliferation inhibition and apoptosis of K562 leukemia cells induced by LiCl is probably related with the G(2)/M cell cycle arrest, the bcr/abl mRNA expression down-regulation and the status of Na(+), K(+), or Li(+) ion channels on K562 leukemia cells.

To explore the regulation mechanism of survivin gene, the NB4 and HL-60 cells were used in experiments, the cell culture in vitro and cell morphological observation were performed and survivin mRNA expression was detected by semi-quantitative RT-PCR. The results showed that the survivin expression in NB4 cell was positive. By treatment of 1 micromol/L ATRA, cell differentiation antigen CD11b was gradually increased ([chi = 47.002, P = 0.000) and CD33 was gradually decreased (chi = 1.614, P = 0.806) with time. Simultaneously, survivin mRNA expression was down-regulated and the cell cycle was arrested at G(0)-G(1) phase (chi = 58.566, P = 0.000). ATRA could down-regulate the survivin mRNA expression of HL-60 cell, but G-CSF, GM-CSF and PHA could up-regulate the survivin expression of HL-60 cell. The cytokine could regulate survivin expression in gene transcription level. The up-regulation of survivin expression was observed while HL-60 cell was stimulated by PHA. The survivin gene expression could be blocked by the survivin antisense oligonucleotide. The survivin mRNA expression of NB4 cell was inhibited by 100 nmol/L-1000 nmol/L survivin antisense oligonucleotide in a dose-dependent manner. The survivin mRNA expression in the NB4 cell was obviously inhibited in 600 nmol/L survivin AS-ODN groups (38%) while the AS-ODN dose increases, the inhibition rate does not descend, but was not inhibited in the control groups, liposomes groups and ODN groups. After NB4 cell was treated by survivin AS-ODN, the typical morphological changes for the apoptosis emerged in NB4 cell. These changes were not found in control groups. It is concluded that PHA, GM-CSF and G-CSF can up-regulate the survivin gene expression, but survivin AS-ODN and ATRA can down-regulate survivin gene expression. The cell cycle arrest at G(0)-G(1) phase while the survivin gene expression was down-regulated by ATRA. It suggested that the survivin gene expression is very related to cell cycle. The morphological changes of cell apoptosis can be observed when the survivin gene expression of NB4 cell was suppressed.

To investigate the inhibition of tumor cell lines' growth and the demethylation of p16 gene by a component of natural drug, CDP.

To investigate the relationship between the expression of phosphoenolpyruvate carboxykinase (PEPCK) gene and insulin resistance induced by high-fat diet and the effect of rosiglitazone, a thiazolidinedione drug.

To investigate the therapeutic effect of nano-sized liposomal adriamycin (NLADR) administered by various routes on rabbits bearing advanced breast tumors.

To study the effect of endothelin-1 (ET-1) and its antagonists on the expression of endothelin and its receptors mRNA in HSC-T6 cells.

To study the effects of Qingdai compound on proliferation and apoptosis of K562 cells, as well as the expression of bcr/abl and JWA mRNA, K562 cells were treated in culture with different concentrations of Qingdai compound (2.5, 5, 7.5, 10 and 20 mg/ml) and harvested at 24 hours. Then morphological changes were observed by light microscopy (LM); expressions of bcr/abl and JWA were detected with semi-quantitative RT-PCR. The results showed that morphological changes were observed as the increment of the Qingdai compound concentration. Inhibition effects on proliferation and apoptosis in K562 cells were seen. A concentration-dependent decreases were found in bcr-abl and JWA mRNA expression of K562 cells. Qingdai compound partially inhibited proliferation and induced apoptosis of K562 cells. Expressions of both bcr/abl and JWA, which took part in cell proliferation and apoptosis, were down-regulated in a dose dependent manner. In conclusion, Qingdai compound can partially inhibit the expressions of bcr/abl and JWA genes in K562 cells, and the clinical effect of Qingdai compound on CML may be associated with apoptosis of leukemic cells.

To elucidate the possible mechanism of differentiation and/or apoptosis in NB4, K562 cells induced by tributyrin (TB), a histone deacetylase inhibitor (HDACi), the level of acetylated histone H3 was detected by Western blot, p21(WAF1) expression was detected by semi-quantitative RT-PCR. The results showed that histone H3 hyperacetylation was detected in NB4 (or K562) cells after treatment with TB 0.1 mmol/L (or TB 0.5 mmol/L) for 16 hours in a dose-dependent manner. p21(WAF1) dose-dependently increased at RNA level in these two cell lines treated by TB 0.1 mmol/L. The level of p21(WAF1) mRNA increased at 2 hours after TB treatment, reaching peak at 16 hours, and maintaining for 48 hours. In conclusion, the mechanism of differentiation and apoptosis in NB4, K562 cells induced by tributyrin may associate with its up-regulation of acetylated histone and p21(WAF1) mRNA level.

To study the gene expression profile in K562 cells treated by IFN-alpha, so as to provide some information about the potential mechanism of IFN-alpha curing CML, the changes of gene expression were examined with the DNA array in K562 cells before and after treatment with IFN-alpha. The results showed that no gene expression difference more than 2.5 times in K562 cells was found on the first day after treatment with IFN-alpha (200 U/ml), then the genes significant expression difference increased step by step, and reached the peak on the forth day. In all examined genes, 97 genes significant expression difference were detected, 86.60% (84/97) gene of interest out of those gene were up-regulated, 13.40% (13/97) were down-regulated. In these 97 genes with significant expression difference, cell regulator protein genes accounted to 23.71% (23/97), surface receptor genes 14.43% (14/97), oncogenes and tumor suppressors 11.34% (11/97), extracellular communication proteins 9.28% (9/97), cell adhesion molecular genes 8.25% (8/97) and the other genes accounted to 32.99% (32/97). JAK1 was up-regulated to 3.78 times, JAK2 to 15.43, STAT1 and STAT2 were up-regulated to 11.98 and 8.11 times respectively, and these genes are components of JAK-STAT pathway. The number of different genes began to decrease on the fifth day. There were still 9 genes that had expression difference more than 3 times on the twenty-first day. It is concluded that when concentration of IFN-alpha was 200 U/ml, the forth day should be considered as the best time to examine change of gene expression in K562 cells treated by IFN-alpha. IFN-alpha realizes its biological functions through the JAK-STAT pathways and it may be one of the mechanisms for curing CML with IFN-alpha.

To examine whether Chinese medical herb Pueraria crude extract (CP) and standard of pure puerarin (SP) possess the same neuroprotective effects during concomitant ethanol (EtOH) treatment.

To investigate the expression profile of genes which are involved in IFN antiviral activity and IFN signal transduction pathway in Hep G2 and HepG2.2.15 cells.

To investigate the effect of human interleukin-4 (hIL-4) on the expression of E-selectin and ICAM-1 on bovine aortic endothelial cells(BAEC) activated with TNF-alpha.