Continuous infusion of a large dose of CF (folinic acid) and 5-FU combined with CDDP in the treatment of advanced esophageal cancer.

5-fluorouracil (5-FU) and cisplatin (CDDP) are common chemotherapy drugs used in the treatment of patients with advanced esophageal cancer. We investigated the efficacy of adding a continuous infusion of a large dose of a common adjuvant, citrovorumfactor (CF), to the traditional 5-FU/wCDDP regimen. 50 patients with advanced esophageal cancer were treated with a continuous infusion of CF, 5-FU, and CDDP, and the short-term effects, adverse reactions, and survival periods after treatment were analyzed. Overall, the treatment was effective in 58% of patients, and the therapeutic effects of the first-line of chemotherapy were significantly better than the second-line (u = 4.121, p < 0.05). Patients experienced severe nausea and vomiting in 18.7% of the treatment cycles and experienced severe hair loss or leucopenia in 1.9% of the treatment cycles. The majority of the treatment cycles produced only mild side effects. The median survival period following chemotherapy treatment was 10.6 months (95% confidence interval was 8.146 ~ 13.054 months), with the median survival time of patients with a Karnofsky Performance Status (KPS) score ≥ 80 being significantly longer than that of patients with KPS scores < 80 (χ2 = 41.595, p < 0.05). The median survival time of patients with metastasis to the lymph nodes and surrounding tissue was significantly longer than that of patients with visceral metastasis (χ2 = 32.246, p < 0.05). Cox regression analysis showed that KPS scores before the treatment < 80 (relative risk (RR= = 1.635) and the incidence of visceral metastasis (RR = 1.875) were associated with survival time (p < 0.05). These results suggest that the continuous infusion of a large dose of CF, 5-FU, and CDDP as chemotherapy treatment of advanced esophageal cancer can produce promising short-term results and decrease adverse reactions.

[Lentivirus-mediated gene transfer of human sTRAIL induced apoptosis in SGC-7901 cells].

OBJECTIVE: To construct self-inactivating (SIN) lentiviral vector carrying human soluble tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) gene and to observe the effects of sTRAIL gene on apoptosis in SGC-7901 cells, so as to assess the value of sTRAIL in gene therapy for gastric cancer. METHODS: The bicistronic SIN lentiviral transfer plasmid containing sTRAIL gene and internal ribosomal entry site-green fluorescent protein gene (IRES-GFP) was constructed. Recombinant lentivirus containing sTRAIL were packaged using liposome by lentiviral packing system. Several cell lines including HL-7702, HLF-1 and SGC-7901 cells were infected with the viral supernatant. Flow cytometry was used to measure apoptosis of cells and recombinant sTRAIL. protein was assayed by ELISA at 24 h after infection. RESULTS: The lentiviral transfer plasmid pXZ208-sTRAIL was constructed, and the virus titres were above 10(6) IU/mL in the supernatant. SGC-7901 cells were efficiently infected by recombinant virus. The apoptosis rate of SGC-7901 cells was increased with the virus multiplicity of infection (MOI) increasing. When the MOI was > or = 0.5, a dose-dependent apoptosis rate was observed. At MOI of 6.0, the highest apoptosis rate (29.12 +/- 2.87)% was observed, while the expression of sTRAIL in the supernatant was only (34.08 +/- 3.43) ng/mL. However, no significant apoptosis was observed in HL-7702 cells and HLF-1 cells. CONCLUSION: Recombinant lentivirus carrying human sTRAIL gene can efficiently infected SGC-7901 cells, which induced apoptosis in SGC-7901 cells in vitro by secreting bioactive sTRAIL protein. However, this effect is not seen in normal cells.

Combinational effect of PPARγ agonist and RXR agonist on the growth of SGC7901 gastric carcinoma cells in vitro.

In order to investigate the inhibitory effects and mechanisms of troglitazone (TGZ), a peroxisome proliferator-activated receptor γ (PPARγ) agonist, and retinoid X receptor (RXR) agonist (9-cis-retinoic acid (RA)) on gastric carcinoma cells SGC7901, SGC7901 cells were treated with TGZ and 9-cis-RA, respectively, or in combination. Then, the cell growth, apoptosis, morphological changes, and the expression of PPARγ, RXRγ, Bcl-2, and Bax were detected by MTT assay, flow cytometry, HE staining, immunocytochemistry staining, and Western blot assay, respectively. Our results showed that the growth of SGC7901 cells was inhibited and the cells got sparser at the concentrations of 50 µmol/L TGZ, 20 µmol/L 9-cis-RA, or combination of TGZ (25 µmol/L) and 9-cis-RA (10 µmol/L). Immunocytochemistry and Western blot showed that after 72 h, the expression of PPARγ, RXRγ, and Bax were upregulated; Bcl-2 was downregulated compared with the negative control group. These data indicated that PPARγ agonist and RXR agonist could inhibit the proliferation of SGC7901 cells via inducing the apoptosis, which involved the increase in the level of Bax/Bcl-2. The combination of RXR agonist and PPARγ agonist could induce the maximal inhibitory effects on tumor growth and apoptosis via promoting the formation of RXR/PPARγ heterodimer.

Reversion of multidrug resistance by SKI-II in SGC7901/DDP cells and exploration of underlying mechanisms.

In order to investigate whether SKI-II could reverse drug resistance and its possible mechanisms, we treated SGC7901/DDP cells with SKI-II or SKI-II in combination with DDP. Then cell growth, apoptosis, micro- morphological changes, and expression of SphK1, P-gp, NF-kB, Bcl-2 and Bax were assessed by MTT assay, flow cytometry, electron microscopy, immunocytochemistry and Western blot assay respectively. SGC7901/DDP cells were insensitive to cisplatin 2.5 mg/L, but when pretreated with SKI-II, their proliferation was inhibited by cisplatin 2.5mg/L significantly, the inhibition rate increasing with time and dose. The apoptosis rate was also significantly elevated. Expression of SphK1 and P-gp was decreased significantly, Pearson correlation analysis showing significant correlation between the two (r=0.595, P<0.01). Expression of NF-kB and Bcl-2 was decreased significantly, while that of Bax was increased, compared to the control group. There were significant correlations between SphK1 and NF-kB(r=0.723, P<0.01), and NF-kB and Bcl-2(r=0.768, P<0.01). All these data indicated that SKI-II could reverse drug resistance of SGC7901/DDP to cisplatin by down-regulating expression of P-gp and up-regulating apoptosis through down-regulation of SphK1. The increased apoptotic sensitivity of SGC7901/ DDP to cisplatin was due to the decreasing proportion of Bcl-2/Bax via down-regulating NF-kB.