[Correlation of aldo-keto reductases with prostate cancer and intervention with traditional Chinese medicine].

The androgen receptor signaling pathway is a key factor in the development and progression of prostate cancer. Aldo-keto reductases AKR1C1-AKR1C4 play an important role in the synthesis and metabolism of androgens in the body, and their expressions influence the androgen receptor signaling pathway and consequently the development and progression of prostate cancer. For the treatment of androgen-resistant prostate cancer, which cannot be cured currently, Chinese medicine and phytotherapy are receiving more and more attention for the mild, long-lasting and multi-target advantages of the small molecules of traditional Chinese medicine. This review summarizes the roles of aldo-keto reductases in the progression of prostate cancer and compares the anti-tumor activities of small molecules in Chinese medicine targeting aldo-keto reductases, hoping to provide a basis for the discovery of new targets for prostate cancer and the development of anti-tumor drugs.

Gap junction composed of connexin43 modulates 5­fluorouracil, oxaliplatin and irinotecan resistance on colorectal cancers.

Chemotherapy is one of the most commonly used therapeutic strategies for metastatic colon cancer. However, the development of resistance to chemotherapeutic agents limits their application in clinical use. The underlying mechanisms of this resistance development require further elucidation. The current study investigated the effects of connexin43 (Cx43) gap junctions on 5­fluorouracil (5­FU), oxaliplatin and irinotecan in colon cancer cells. Three different methods were used to manipulate Cx43 gap junction function: i) Cell culture at different densities; ii) pretreatment with a Cx43 specific inhibitor or enhancer; and iii) Cx43 gene knock­down. Results indicated that the cell toxicity of 5­FU, oxaliplatin and irinotecan was cell density­dependent, which was mediated by gap junctions. Downregulation of Cx43 gap junction functioning attenuated 5­FU, oxaliplatin and irinotecan toxicity in colon cancer cells, which was increased in cells treated with a Cx43 gap junction function enhancer. Thus, the results of the present study suggest that resistance to 5­FU, oxaliplatin and irinotecan in colon cancer cells was relative to Cx43 expression loss as cancer developed, which may indicate a novel basis for therapeutic strategy development to combat drug resistance in numerous cell types, in addition to colon cancer cells.

[Expression of Rictor and mTOR in colorectal cancer and their clinical significance].

OBJECTIVE: To explore the expression of Rictor and mTOR in the colorectal cancer and their clinical significance. METHODS: The expression levels of Rictor and mTOR in HCT116, SW480, LoVo and HCoEpiC cells were detected by indirect immunofluorescence and Western blotting. Sixty-two paraffin-embedded surgical specimens of colorectal cancer tissue and adjacent tissues were examined for Rictor expression using immunohistochemistry. The association of the expression levels of Rictor protein with the clinicopathologic features and the overall survival of the patients was analyzed. RESULTS: The expression level of Rictor was significantly higher in colorectal cancer tissues than in the adjacent tissues (P<0.05). The expression levels of Rictor and mTOR in the colon cancer cell lines were higher than those in human normal colon epithelial cell line HCoEpiC. The expression of Rictor was correlated with Dukes stage and lymphatic metastasis of the tumors but not with other clinicopathological parameter (P>0.05). Patients with Rictor expression had a lower overall survival rate than those without Rictor expression. CONCLUSION: Rictor overexpression is associated with the carcinogenesis and progression of colorectal cancer and can be an independent indicator for evaluating the prognosis of colorectal cancer patients.

[Selective cytotoxic effect of lentivirus-mediated double suicide gene transfer on human gastric adneocarcinoma cells].

OBJECTIVE: To study the selective cytotoxic effect of lentivirus-mediated double suicide gene (CD/TK) against human gastric carcinoma cells SGC-7901 in vitro. METHODS: SGC-7901 cells were infected with FGW-KDRP-CD/TK vector and the infection efficiency was observed under a fluorescence microscope. The morphological changes of the infected cells were observed by Giemsa staining. Flow cytometry (FCM) was employed for cell cycle analysis, and the expression of CD/TK was detected by RT-PCR. The infected cells were then treated with the prodrugs ganciclovir (GCV) and/or 5-fluorocytosine (5-FC) at different concentrations, and the cytotoxic effects were evaluated using MTT method. RESULTS: The infection efficiency of the lentiviral vector in SGC-7901 cells increased with the titer of the virus, which produced no significant effect on the cancer cell morphology in vitro or on the percentages of G0-G1, G2-M and S phase cells (P>0.05). RT-PCR demonstrated the expression of CD/TK gene in SGC-7901 cells infected by FGW-KDRP-CD/TK. The infected cells were highly sensitive to the prodrugs with a dose-dependent cytotoxic effect within a specific concentration range of the drugs, whereas the non-infected cells were not sensitive to the prodrugs. Combined use of the two prodrugs produced an obviously stronger inhibitory effect than either of the them (P<0.05). When combined, GCV and 5-FC at the concentration of 0.1+40, 1+80, 10+160, and 100+320 mg/L demonstrated a synergetic effect with a CDI<1. CONCLUSION: Lentivirus-mediated CD/TK fusion gene system can selectively kill gastric cancer cells, and the two prodrugs show a synergistic cytotoxic effect.

[Preliminary effect of VEGF promoter-driven recombinant adenovirus containing double suicide genes on apoptosis of human gastric carcinoma cells].

OBJECTIVE: To study the effect of the adenovirus containing CD/TK fusion gene controlled by the human vascular endothelial growth factor (VEGF) promoter on apoptosis of human gastric carcinoma cells SGC-7901. METHODS: VEGF-expressing SGC-7901 cells were infected by the recombinant adenovirus Ad-VEGFP-CD/TK, and the infection efficiencies were observed with fluorescence microscopy. The toxic effect and intracellular calcium concentration induced by 5-fluorocytosine (5-FC) and ganciclovic (GCV) were determined by light microscopy, electron microscopy and flow cytometry. RESULTS: The transfection efficiency of the recombinant adenovirus in SGC-7901 cells increased with the viral titer. At the multiplicity of infection (MOI) of 100, 5-FC and GCV could induce apoptosis of SGC-7901 cells within a given dose range in a dose- and time-dependent manner, and apoptotic changes of the cells were observed with electron microscopy. Apoptotic peak was also detected by flow cytometry. Cell cycle analysis revealed increased cell percentage in G(0)-G(1) phase and decreased percentage of cells in G(2)-M and S phases in response to treatment with the pro-drugs, which also induced marked elevation of intracellular calcium concentration in the infected cells. CONCLUSIONS: CD/TK fusion gene system driven by VECF promoter selectively induces apoptosis of VEGF-expressing SGC-7901 cells, the action of which is probably mediated by intracellular calcium variation.

[Targeted killing of colorectal tumor cells by lentiviral constructs containing CD/TK suicide genes and KDR promoter].

OBJECTIVE: To investigate the selective killing of colorectal tumor cells by lentivirus-mediated double suicide gene under the regulation of KDR promoter. METHODS: 293T packaging cells were transfected with the plasmid FGW-KDRP-CD/TK to obtain the infectious viruses. KDR-expressing LoVo cells and LS174T cells that did not produce KDR were transfected with the recombinant virus, and the transfection efficiency was evaluated by the fluorecence microscope. RT-PCR was employed to examine the expression of CDglyTK. After treatment of the cells with 5-FC and GCV, the killing effects on the two cell lines were evaluated. RESULTS: The recombinant construct showed similar infection rate of the two cell lines. RT-PCR demonstrated that CDglyTK gene was expressed only in LoVo cells infected with FGW-KDRP-CD/TK but not in LS147T cells, and the sensitivity of the two cell lines to the prodrugs was significantly different (P<0.001). The killing effect of the double suicide gene was much stronger than that of single suicide gene administered (P<0.001). CONCLUSION: The double suicide gene driven by KDR promoter has specific killing effect on the KDR-expressing colorectal tumor cells.

[Effects of the lipid-lowering drugs on endothelial hyperplasia in inferior vena cava grafts in dogs].

OBJECTIVE: To investigate the effects of the lipid-lowering drugs in alleviating endothelial hyperplasia in the inferior vena cava (IVC) grafts in dogs. METHODS: The Dacron grafts seeded with autologous venous fragments were implanted into the IVC of 20 dogs, including 12 dogs receiving oral lipid-lowering drugs serving as the treatment group and the other 8 without medication as the control group. The levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-ch) and high-density lipoprotein cholesterol (HDL-ch) in the serum were measured regularly, and all the grafts harvested to measure the thickness of the endothelium. RESULTS: The total patency rate of the IVC were higher in the treatment group (75%) than in the control group (37.5%), and new endothelial lining was formed two weeks after the operation. Compared with the control group, the endothelial thickness of the grafts at the proximal (P<0.01), middle (P<0.05) and distal segments (P<0.05) of the IVC were all smaller in the treatment group, which also had lower serum LDL-ch and TC levels (both P<0.05) but with comparable HDL-ch levels (P>0.05). CONCLUSION: Administration of lipid-lowering drugs may reduce the level of serum LDL-ch and TC and the endothelial thickness of the grafts to improve the patency rate of the vessels.