胃癌分子免疫学研究进展

Necessity of monitoring blood trace elements in children with Helicobacter pylori infection

AIM: To analyze the necessity of monitoring blood trace elements in children with Helicobacter pylori (H. pylori) infection, and assess the value of trace elements in the treatment of children with H. pylori infection.

METHODS: Eighty children without H. pylori infection (control group) and 80 children with H. pylori infection (observation group) were included. The children in the observation group all accepted triple therapy for two weeks, of whom 40 additionally accepted symptomatic treatment by zinc or iron supplementation (symptomatic treatment subgroup), and another 40 received simultaneous supplementation of zinc and iron (non-symptomatic treatment subgroup). The levels of zinc, iron, copper, calcium and magnesium and the incidence of anemia were compared between the observation group and control group, and H. pylori infection, trace elements, and anemia were compared between the two subgroups after 1 mo of treatment.

RESULTS: Zinc and iron levels were significantly higher in the observation group than in the control group (P < 0.05), although there were no statistically differences in copper, calcium or magnesium levels between the two groups (P > 0.05). In the observation group, the percentages of children with zinc or iron deficiency were significantly higher than those in the control group (31.25% vs 13.75%, 36.25% vs 17.50%, P < 0.01), although the percentages of children with deficiency of other elements had no significant differences (P > 0.05). The incidence of anemia was significantly higher in the observation group than in the control group (40.00% vs 18.75%, P < 0.01). The numbers of children with zinc deficiency, iron deficiency, H. pylori infection or anemia were significantly lower in the symptomatic treatment subgroup than in the non-symptomatic treatment subgroup (5 vs 16, 2 vs 13, 3 vs 11, 1 vs 6, P < 0.05 or P < 0.01).

CONCLUSION: H. pylori infection children may develop zinc or iron deficiency and have a higher incidence of iron-deficiency anemia. Zinc or iron supplementation during H. pylori eradication treatment is conducive to recovery in H. pylori infection children.

Roles of mast cells in gastric carcinogenesis

There is a growing acceptance that mast cells play an active role in tumor growth. However, little is known about the role of mast cells in gastric carcinogenesis. Accumulated evidence suggests that mast cells play critical roles in gastric carcinogenesis in terms of promoting angiogenesis, modulating immune responses and participating in tissue remodeling. All these roles are closely related to tumor growth and metastasis. In this paper, we review recent advances in research on the roles of mast cells in gastric carcinogenesis. We also discuss the clinical application of drugs regulating mast cell function in tumors.

SiRNA-mediated silencing of the RUNX2 gene inhibits proliferation and induces apoptosis in human gastric cancer cell line SGC7901

AIM: To detect the expression of runt-related transcription factor gene 2 (RUNX2) in human gastric cancer cell line SGC7901 and to investigate the influence of small interfering RNA (siRNA)-mediated silencing of the RUNX2 gene on the proliferation and apoptosis of SGC7901 cells.

METHODS: SGC7901 cells were divided into three groups: blank control group, negative control group (transfected with an empty vector), and experiment group (transfected with RUNX2 siRNA). After SGC7901 cells were transfected with RUNX2 siRNA, the mRNA and protein expression of RUNX2 was examined by RT-PCR and Western blot, respectively; cell proliferation was evaluated by MTT assay; and cell apoptosis was detected by flow cytometry (FCM).

RESULTS: Compared with cells of the blank control group, the expression of RUNX2 mRNA (0.27 ± 0.068 vs 0.45 ± 0.058, F = 75.6, P < 0.01) and protein (F = 123.8, P < 0.001) was down-regulated in cells transfected with RUNX2 siRNA. At 24, 48, and 72 h after transfection, the proliferation rates of SGC7901 cells transfected with RUNX2 siRNA were significantly lower than those of non-transfected cells (0.23 ± 0.039 vs 0.32 ± 0.012; 0.31 ± 0.037 vs 0.45 ± 0.074; 0.52 ± 0.021 vs 0.72 ± 0.006; F = 173.744, 14.012, 253.145; all P < 0.001). The apoptosis rate of SGC7901 cells transfected with RUNX2 siRNA was significantly higher than those of cells of the blank control group and negative control (45.65% ± 0.64% vs 4.46% ± 0.27%, 4.23% ± 0.33%, both P < 0.01).

CONCLUSION: RUNX2 expression was detected in SGC7901 cells. SiRNA-mediated silencing of the RUNX2 gene can inhibit proliferation and induce apoptosis in SGC7901 cells. RUNX2 may be a new gene therapy target for gastric cancer.

Antitumor effects of cisplatin and CIK cells against human gastric cancer in nude mice

AIM: To investigate the antitumor effects of cisplatin and cytokine-induced killer (CIK) cells, alone and in combination, against human gastric cancer in nude mice.

METHODS: Peripheral blood mononuclear cells (PBMCs) were obtained from healthy volunteers by Ficoll gradient centrifugation. CIK cells were induced by culturing PBMCs in the complete medium containing recombinant human interferon-g (rhIFN-g), anti-CD3 monoclonal antibody (mcAb), recombinant human interleukin-2 (rhlL-2), and recombinant human interleukin-1 (rhlL-1). Eighty Balb/c nude mice were subcutaneously transplanted with gastric cancer cells (SGC-7901) in the exponential growth phase. Ten days later, these mice were randomly divided into four groups: control group, cisplatin group, CIK cell group and cisplatin plus CIK cell group, which were given normal saline, cisplatin, CIK cells, and cisplatin plus CIK cells for five days, respectively.

RESULTS: Compared with normal saline, cisplatin and CIK cells, alone and in combination, extended the survival time of nude mice bearing tumors and decreased tumor weight (all P < 0.01). The reduced rate of tumor growth was significantly higher in the cisplatin plus CIK cell group (57.8%) than in the control group (P < 0.01). The levels of erythrocyte C3b receptor significantly increased, and those of erythrocyte immune complex receptors significantly decreased in all treatment groups when compared to the control group (all P < 0.01).

CONCLUSION: Cisplatin and CIK cells in combination is better than alone in inhibiting the growth of human gastric cancer in nude mice.

Recombinant human growth hormone promotes tumor growth and VEGF expression in subcutaneous xenografts derived from human gastric carcinoma SGC-7901 cells in nude mice

AIM: To investigate the effects of recombinant human growth hormone (rhGH) on tumor growth and VEGF expression in subcutaneous xenografts derived from human gastric carcinoma SGC-7901 cells in nude mice.

METHODS: The expression of growth hormone receptor (GHR) in human gastric carcinoma cell line SGC-7901 was detected by immunocytochemistry. Thirty nude mice bearing subcutaneous xenografts derived from carcinoma SGC-7901 cells were randomly divided into three groups: control group, low-dose rhGH group and high-dose rhGH group. The low- and high-dose rhGH groups were injected with rhGH at doses of 0.5 and 2.5 U/(kg•d) once a day for two weeks, respectively, while the control group was injected with equal volumes of normal saline for the same duration. The changes in body weight and tumor volume were recorded. The content of serum VEGF in peripheral blood was analyzed by enzyme-linked immunosorbent assay (ELISA). The expression of VEGF mRNA and protein in tumor tissue was detected by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively.

RESULTS: GHR is highly expressed in SGC-7901 cells. After treatment with rhGH for three days, the tumor volume was significantly larger in the two rhGH groups than in the control group (both P < 0.05). High-dose rhGH revealed stronger tumor growth-promoting effect than low-dose one (P < 0.05). No significant difference was found in the body weight of nude mice among the three groups (all P > 0.05). The content of serum VEGF was elevated more obviously in the high-dose rhGH group than in the low-dose rhGH group and the control group. (252.94 ng/L ± 15.32 ng/L vs 167.60 ng/L ± 9.54 ng/L and 49.94 ng/L ± 5.73 ng/L, respectively; both P < 0.05). The expression level of VEGF protein in tumor tissue was significantly higher in the two rhGH groups than in the control group. The relative expression level of VEGF mRNA was much higher in the high-dose rhGH group than in the low-dose rhGH group and the control group (0.647 ± 0.0447 vs 0.412 ± 0.0351 and 0.323 ± 0.0258, respectively; both P < 0.05).

CONCLUSION: RhGH can promote tumor growth and VEGF expression in subcutaneous xenografts derived from human gastric carcinoma SGC-7901 cells in nude mice.