Proliferation and differentiation of Gastric Mucosal Cells in Culture

胃粘膜细胞的增殖和分化用离心淘析器分离兔胃粘膜细胞，并根据细胞大小进行分级。通过流式细胞术对这些分级细胞的细胞周期分析表明，15-35%的细胞处于S期，因此胃干细胞广泛分布在各个分级中。本研究观察了TGF α、TGF β、ET-1等多种生长因子对人胃粘膜上皮细胞的作用，并对人胃粘膜上皮细胞进行了TGF α和表皮生长因子受体的免疫组织化学定位。TGF α和EGFR免疫反应共定位于表面粘膜上皮细胞，壁细胞和胃干细胞（PCNA阳性细胞）。在消化道周围的再生胃粘膜中，TGF α免疫反应性与PCNA阳性细胞共定位于再生腺的基部。因此，TGF α可能以自分泌或旁分泌方式支持胃粘膜细胞增殖。用RT-PCR方法检测人胃活检组织中TGF α mRNA的表达。研究表明，随着胃溃疡的愈合，TGF α mRNA在再生胃粘膜中的表达逐渐增加，c-myc基因在多种胃肠道肿瘤中均呈过表达。c-myc反义寡核苷酸（18 mer和27 mer）在0.1- 10 μ M浓度下对MKN 45胃癌细胞的生长抑制率为40-75%，而正义寡核苷酸则无此作用。缺口末端标记法（TUNEL）显示凋亡细胞的频率与肿瘤细胞生长受抑的程度有关。提示c-myc反义寡核苷酸治疗胃癌有希望。

PROLIFERATION AND DEFFERENTIATION OF GASTRC MUCOSAL CELL IN CULTURERabbit gastric mucosal cells were isolated and fractionated by a centrifugal elutriator according to cell-size. Cell cycli analysis of these fractionated cells by flowcytometry demonstrated that 15-35% of cells are in S-phase and therefore gastric stem cells are widely distributed in various fractions. Effects of a variety of growth factors including TGFa, TGFb, ET-1 on these gastric mucosal cells were examined in this study.Immunohistochemical localization of TGFa and epidermal growth factor receptor was performed using biopsy samples of human stomach. Both TGFa and EGFR immunoreactivity were co-localized in surface mucous epithelias cells, parietal cells, and gastric stem cells (PCNA-positive cells). In the regenerating gastric mucosa arround peptic uleer, TGFa immunoreactivity was co-localized with PCNA-positive cells at the basal portion of the regenerative glands. Thus, TGFa may support gastric mucosal cell proliferation in a autocrine or paracrine fashion. TGFa mRNA expression was also examined in biopsy samples of human stomach using RT-PCR method. It was demonstrated that TGFa mRNA expression in regenerating gastric mucosa is increased with gastric ulcer healing.Overexpression of c-myc gene has been detected in a variety of tumors in the gastrointestinal tract. Antisense oligonneleotides to c-myc (18 mer and 27 mer) inhibited growth of MKN45 gastric cancer cells by 40-75% at concentrations of 0.1-10uM, while sense oligonucleotide did not. TUNEL (Nick-end labeling) method revealed that frequency of apoptotic cells is correlated with the degree of supression of tumor cell growth. These results suggests that antisense oligonucleotide to c-myc may be promising for the treatment of gastric cancer.