Adam L, Crépin M, Savin C, Israël L
Institut d'Oncologie Moléculaire et Cellulaire Humaine, Bobigny, France.
Cancer Res. 1995 Nov 15;55(22):5156-60.
Using a highly tumorigenic human breast cancer model (Ha-ras-transfected MCF7 cell line) we analyzed the efficacy of the differentiation-inducing agent sodium phenylacetate (NaPA), both in vitro and in vivo. NaPA-treated MCF7ras cells showed dose-dependent growth inhibition from 2.5 to 15 mM without apparent toxicity. Western blot analysis showed a Bcl-2 down-regulation after 48 h treatment with 5 mM NaPA, together with apparition of apoptotic nuclei by DAPI staining. Mice bearing MCF7ras xenografts (n = 40) were treated for 2 weeks through s.c.-delivering osmotic pumps, followed by 6 weeks of daily i.p. NaPA administration. After 3 weeks, the treated tumors showed growth arrest without regression for the whole observation time, e.g., 12 weeks. Immunohistochemical analysis showed Bcl-2 down-regulation and differentiation patterns: decrease of Ki-67 and increase of steroid receptors (estrogen and progesterone receptors) compared to controls. Cells cultured from treated tumors (II.b) displayed pseudotrabecular disposition as MCF7ras cells treated in vitro. They also showed a higher NaPA sensitivity, together with 70% Bcl-2 down-regulation as compared to the derived cells of untreated tumors (II.a). When reinjected into nude mice, II.b cells induced only one poorly vascularized, noninvasive tumor (8%) with lower proliferation index, 100% progesterone receptor positive cells, and 35% terminal deoxynucleotidyltransferase-mediated dUTP-X nick end labeling (+) nuclei, as compared to 100% induction of highly vascularized and invasive tumors with 3% terminal deoxynucleotidyltransferase-mediated dUTP-X nick end labeling (+) nuclei induced by II.a cells.
利用一种高致瘤性的人乳腺癌模型（Ha-ras转染的MCF7细胞系），我们在体外和体内分析了分化诱导剂苯乙酸钠（NaPA）的疗效。用NaPA处理的MCF7ras细胞在2.5至15 mM浓度下呈现剂量依赖性生长抑制，且无明显毒性。蛋白质免疫印迹分析显示，用5 mM NaPA处理48小时后，Bcl-2表达下调，同时经4',6-二脒基-2-苯基吲哚（DAPI）染色可见凋亡细胞核。对携带MCF7ras异种移植瘤的小鼠（n = 40）通过皮下植入渗透泵进行2周治疗，随后每天腹腔注射NaPA持续6周。3周后，在整个观察期（即12周）内，治疗后的肿瘤显示生长停滞但未消退。免疫组织化学分析显示Bcl-2表达下调和分化模式：与对照组相比，Ki-67减少，类固醇受体（雌激素和孕激素受体）增加。从治疗后的肿瘤中培养的细胞（II.b）呈现出与体外处理的MCF7ras细胞相同的假小梁排列。它们还表现出更高的NaPA敏感性，与未治疗肿瘤的衍生细胞（II.a）相比，Bcl-2表达下调70%。当将II.b细胞重新注射到裸鼠体内时，与II.a细胞诱导100%的高血管化侵袭性肿瘤且3%的细胞核末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（+）相比，II.b细胞仅诱导出一个血管化不良、非侵袭性的肿瘤（8%），其增殖指数较低，100%的细胞孕激素受体阳性，35%细胞核末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（+）。
