Chen Daoda

Expression of vascular endothelial growth factor C and its correlation with lymph node metastasis in colorectal carcinoma

SummaryTo study the expression of vascular endothelial growth factor C (VEGF-C) in colorectal carcinoma and its relationship with lymph node metastasis, the expression of VEGF-C protein in colorectal carcinoma tissues obtained from 94 patients who underwent radical resection was immunohistochemically detected. Meanwhile, the expression of VEGF-C mRNA in 4 colorectal carcinoma cell lines was examined by reverse transcription polymerase chain reaction (RT-PCR). VEGF-C protein was found to be expressed in 53.2% of patients. The expression was more frequently detected in tumors with lymph node metastasis than in those without metastasis (P<0.01), and there was significant correlation between its expression and lymphatic invasion, TNM stage (P<0.01). However, no significant correlation was found between its expression and the age, gender, tumor location, depth of invasion and vascular invasion. 2 of the 4 colorectal carcinoma cell lines, including LoVo and LoVo-5FU, expressed VEGF-C mRNA. The expression of VEGF-C is closely related to lymph node metastasis, and it might take part in the tumor lymphangiogenesis.

Involvement of M3 cholinergic receptor signal transduction pathway in regulation of the expression of chemokine MOB-1, MCP-1 genes in pancreatic acinar cells

SummaryWhether M3 cholinergic receptor signal transduction pathway is involved in regulation of the activation of NF-κB and the expression of chemokine MOB-1, MCP-1 genes in pancreatic acinar cells was investigated. Rat pancreatic acinar cells were isolated, cultured and treated with carbachol, atropine and PDTCin vitro. The MOB-1 and MCP-1 mRNA expression was detected by using RT-PCR. The activation of NF-κB was monitored by using electrophoretic mobility shift assay. The results showed that as compared with control group, M3 cholinergic receptor agonist (10−3 mol/L, 10−4 mol/L carbachol) could induced a concentration-dependent and time-dependent increase in the expression of MOB-1, MCP-1 mRNA in pancreatic acinar cells. After treatment with 10−3 mol/L carbachol for 2 h, the expression of MOB-1, MCP-1 mRNA was strongest. The activity of NF-κB in pancreatic acinar cells was significantly increased (P<0.01) after treated with M3 cholinergic receptor agonist (10−3 mol/L carbachol)in vitro for 30 min. Either M3 cholinergic receptor antagonist (10−5) mol/L atropine) or NF-κB inhibitor 10−2 mol/L PDTC) could obviously inhibit the activation of NF-κB and the chemokine MOB-1, MCP-1 mRNA expression induced by carbachol (P<0.05). This inhibitory effect was significantly increased by atropine plus PDTC (P<0.01). The results of these studies indicated that M3 cholinergic receptor signal transduction pathway was likely involved in regulation of the expression of chemokine MOB-1 and MCP-1 genes in pancreatic acinar cellsin vitro through the activation of NF-κB.

Effect of estrogen on telomerase activity in human breast cancer cells.

SummaryTo investigate the effects of estrogen (E2) on telomerase activity and its mechanism in human breast cancer cells, estrogen receptor positive MCF-7 cells were treated with different concentrations of E2. Telomerase activity was measured by using TRAP-ELISA method, the cell cycle phases analyzed by using flow cytometry, and the expression of Cyclin D1 detected by using immunohistochemistry method. The results showed that telomerase activity levels were increased in MCF-7 cells treated with 10−8 mol/L E2 during the observed period (P<0.05), and E2 increased telomerase activity levels in a dose-dependent manner (10−10-10−8 mol/L); Simultaneously, the cell cycle phases of MCF-7 cells treated with 10−8 mol/L E2 were changed significantly: G0/G1 phase decreased from 60.52% to 50.93%, S phase increased from 29.03% to 30.83%; However, the expression of Cyclin D1 was decreased. It was concluded that estrogen can upregulate telomerase activity of MCF-7 cells, and the effect can be blocked by antiestrogen tamoxifen. Its mechanism may be closely associated with modulation of cell cycle phases.

Effects of Estradiol and Tamoxifen on Proliferation of Human Breast Cancer Cells and Human Endometrial Cells

SummaryThe effects of estradiol and tamoxifen on the proliferation of estrogen receptor positive cells and the relationship between the tamoxifen tolerance and cell origin were investigated. The tissues of human endometrium and breast cancer were randomly selected following dissection for primary cell culture. After the breast cancer cells and endometrial cells were treated with 1×10−8 mol/L estradiol and/or 1×10−6 tamoxifen,3H-labelled thymine nucleotide was used to trace the kinetics of cell proliferation. There was no significant difference in the inhibition on the human endometrial cells between tamoxifen-treated group (6.3%) and control group (6.4%), but tamoxifen could significantly inhibit the proliferation of the human breast cancer cells (45.84%) as compared with control group (52.72%). Moreover, tamoxifen could significantly stimulate the proliferation of tamoxifen resistant breast cancer cells (9.64%) as compared with control group (6.32%). Estradiol could significantly stimulate the proliferation of all the three kinds of cells as compared with control group. The combined use of estradiol and tamoxifen could inhibit the proliferation of the endometrial cells and breast cancer cells as compared with estradiol used alone, but on the tamoxifen resistant breast cancer cells, they could more significantly stimulate the proliferation than E2. It was concluded that E2 could stimulate the proliferation of these three kinds of cells. However, the inhibitive effects of tamoxifen on the proliferation of these cells were dependent on the estradiol.

A modified method for preparation of adriamycin carried by magnetic albumin microspheres

SummaryThe targeting of antineoplastic agents to restricted anatomic sites and specific target cells have been challenged clinicians all the time in cancer chemotherapy, which resulted in recent efforts to focus the effects of existing antitumor agents and treatments on tumor cells and spare their effects on normal cells. The drug-carrier complex, adriamycin carried by magnetic albumin microspheres (ADM-MAM) was prepared by using our discovered new and modified method. The physical feature of the prepared drug-carrier microspheres was much better than by the traditional method in comparison. The successful preparation of the drug-carrier complex, ADM-MAM, is one of the key steps for our later further researches in the targeted chemotherapy.

The effect of nitric oxide/endothelins system on the hepatic ischemia/reperfusion injury.

SummaryThe relationship between the hepatic ischemia/reperfusion (I/R) injury and the balance of nitric oxide/endothelins (NO/ET) was studied. The changes of the ratio of NO/ET and the hepatic injury were observed in a rat hepatic I/R model pretreated with several tool drugs. In the acute phase of hepatic I/R injury, the ratio of plasma NO/ET was reduced from 1.58±0.20 to 0.29±0.05 (P<0.01) and the hepatic damage deteriorated. NO donor L-Arg and ET receptor antagonist TAK-044 could alleviate the hepatic I/R injury to some degree, whereas NO synthase inhibitor L-NAME aggravated the damage. It was concluded that the hepatic I/R injury might be related with the disturbance of the NO/ET balance. Regulation of this balance might have an effect on the I/R injury.

Construction and expression of human PTEN tumor suppressor gene recombinant adenovirus vector

SummaryThe recombinant defective adenovirus vector carrying human PTEN tumor suppressor gene was constructed by using AdEasy-1 system and its expression was detected in human breast cancer cell line MDA-MB-468. Human PTEN cDNA was cloned into adenovirus shuttle plasmid pAdTrack-CMV to generate a recombinant plasmid pAdTrack-CMV-PTEN, then homologeous recombination was carried out in the E. coli BJ5183 by contransforming linearized shuttle vector with adenovirus backbone plasmid pAdEasy-1. The newly recombined defective adenovirus vector Ad-PTEN containing green fluorescent protein (GFP) was packaged and propagated in 293 cells. After being purified by cesium chloride gradient centrifugation, the adenovirus was transfected into human breast cancer cell line MDA-MB-468 in vitro. The expression of PTEN mRNA and protein in infected human breast cancer cell line MDA-MB-468 was detected by RT-PCR and Western blot respectively. The recombinant defective adenovirus vector carrying PTEN gene was constructed successfully. The viral titer of purified adenovirus was 2.5×1010 pfu/mL, and about 70% breast cancer cells were infected with Ad-PTEN when multiplicity of infection (MOI) reached 50. The exogenous PTEN mRNA and protein were expressed in MDA-MB-468 cells infected with Ad-PTEN by RT-PCR and Western blot. The recombinant defective adenovirus vector of PTEN gene was constructed successfully using AdEasy-1 system rapidly, which paved a sound foundation for gene study of breast cancer.

The NO/ET-1 system is involved in the protection of the hepatic ischemic preconditioning

SummaryTo study the relationship between the disturbance of nitric oxide/endothelin-1 (NO/ET-1) and the hepatic ischemia/reperfusion (I/R) injury as well as the regulation of the NO/ET-1 system by the hepatic ischemic preconditioning (IPC), the changes of the NO/ET-1 system and their relationship with the hepatic I/R injury were compared between the I/R group and the IPC+I/R group in a rat hepatic I/R model. 2 h after reperfusion, the liver tissues were examined for expressed inducible nitric oxide synthase (iNOS) mRNA by RT-PCR. In the acute phase of hepatic reperfusion, the ratio of NO/ET-1 was reduced, which was due to the significant reduction of NO2−/NO3− (the metabolic product of NO) and significant elevation of ET-1 in the blood plasma. The content of ALT, AST, LDH and TNF-α in blood plasma, and level of MDA in liver tissue were increased but ATP in liver tissue was reduced, and the hepatic damage was deteriorated. The protection of the hepatic IPC was associated with the elevated ratio of NO/ET-1 caused by the elevation of NO2−/NO3−, and reduction of ET-1 as well. No iNOS mRNA was detected in the liver tissues. It was concluded that hepatic I/R injury was related to the disturbance of NO/ET-1. The protection of the hepatic IPC in the acute phase might be mediated by its regulation of NO/ET-1 system. The cNOS rather than the iNOS generated the NO in this scenario.

The Influence of Phorbol Ester on the Effect of Tamoxifen in Breast Cancer Cells

SummaryTo investigate the correlation between the activity of kinases in the growth factor signal transduction pathway and the development of resistance of breast cancer to tamoxifen, reporter gene regulated by the regulating fragment of CCD1 was transfected into the MCF-7 cells, and the influence of tamoxifen on the reporter gene expression was examined under different conditions of TPA treatment. Our results showed that the reporter gene expression was inhibited by tamoxifen and promoted by TPA. Furthermore, tamoxifen exerts an agonist effect on the reporter gene expression when the cells was treated by TPA previously for 12 h. It is concluded that TPA could induce estrogen-like effect of tamoxifen on estrogen receptor positive breast cancer cells and it may be one of the mechanisms responsible for the development of tamoxifen resistance.

The effect of hydroxyapatite ultrofine powder on the immunity function of tumor-bearing mice

SummaryThe inhibitory effect of hydroxyapatite ultrofine powder (HAUFP) on tumor and the effect on the immunity function of body were investigated. The levels of IL-2 in the spleen cells and serum TNF levels in the tumor-bearing mice at the 7th day and 14th after peritoneal injection of HAUFP were detected by using the methods of colorimetric analysis of MTT and crystal purple decoration, respectively. The disappearance of the ascites of the mice was observed. The results showed that the levels of IL-2 and TNF in the tumor-bearing mice were higher obviously in the drug-treated group than in the control group (P< 0.01), the ascites growth was inhibited. It was suggested that HAUFP could increase the levels of IL-2 and TNF of the tumor-bearing mice and improve the immune function of body.