Human breast cancer: correlation of relapse and survival with amplification of the HER-2/neu oncogene

The HER-2/neu oncogene is a member of the erbB-like oncogene family, and is related to, but distinct from, the epidermal growth factor receptor. This gene has been shown to be amplified in human breast cancer cell lines. In the current study, alterations of the gene in 189 primary human breast cancers were investigated. HER-2/neu was found to be amplified from 2- to greater than 20-fold in 30% of the tumors. Correlation of gene amplification with several disease parameters was evaluated. Amplification of the HER-2/neu gene was a significant predictor of both overall survival and time to relapse in patients with breast cancer. It retained its significance even when adjustments were made for other known prognostic factors. Moreover, HER-2/neu amplification had greater prognostic value than most currently used prognostic factors, including hormonal-receptor status, in lymph node-positive disease. These data indicate that this gene may play a role in the biologic behavior and/or pathogenesis of human breast cancer.     

人类表皮生长因子受体2蛋白在宫颈癌组织中的表达及意义

目的观察宫颈癌组织中人类表皮生长因子受体2（HER-2/neu）蛋白表达及其在宫颈癌发生发展中的作用。方法应用免疫组织化学方法检测20例正常宫颈组织、30例宫颈上皮内瘤样病变（CINⅠ-Ⅲ）和50例宫颈癌组织中HER-2/neu蛋白表达。结果宫颈癌组织中HER-2/neu蛋白表达显著高于宫颈上皮内瘤样病变（P〈0.01）,正常宫颈组织未见阳性表达;宫颈癌组织中HER-2/neu蛋白表达与肿瘤浸润深度、淋巴结转移、临床分期密切相关（P〈0.05）。结论 HER-2/neu蛋白表达上调可能在宫颈癌发生发展中起重要作用。     

Osteolytic sterol in human breast cancer

Eleven of twelve human breast cancers contained a lipid which increased urinary (45)Ca and (40)Ca excretion of (45)Ca-labeled, parathyroidectomized rats receiving a low Ca diet. The lipid has mobility on thin-layer chromatography and gas-liquid chromatography close to, but not identical with, that of 7-dehydrocholesterol. Authentic 7-dehydrocholesterol has osteolytic activity similar to that of the extracted sterol. Fluorescence and Lieberman-Burchard reactions of the extracted sterol are similar to those of 7-dehydrocholesterol. The lipid was found by thin-layer chromatography in the extracts which had osteolytic activity. Neither the lipid nor osteolytic activity was found in extracts of tissue from two normal human breasts.     

Reversal of adriamycin resistance by verapamil in human ovarian cancer

The effectiveness of adriamycin in the treatment of ovarian cancer and other human tumors has been limited by the development of drug resistance. Verapamil, a calcium channel blocking agent, completely reversed adriamycin resistance in human ovarian cancer cells with moderate (three- to sixfold) degrees of resistance and partially reversed resistance in highly (150-fold) resistant cells. The potentiating effect of verapamil was due to inhibition of adriamycin efflux in the resistant cells. These results have led to a clinical trial of adriamycin and verapamil in refractory ovarian cancer patients.     

HER2/neu ECD毕赤酵母工程菌大规模发酵工艺研究

采用补料分批培养方法,在80 L发酵罐中对HER2/neu ECD工程菌进行高密度发酵,发酵温度28℃,pH值为4.4,溶氧范围25%以上。在湿重值达到180 g/L时开始诱导,甲醇诱导体积分数为0.5%,发酵时间96 h。发酵液离心后,上清经阳离子交换层析,对其表达产物进行纯化。结果表明:在优化发酵条件下,发酵上清通过阳离子交换层析纯化,可获得纯度较高的重组HER2/neu ECD,产量为600 mg/L。     

茶氨酸和其衍生物茶氨酸氯香酰胺对高转移的 人乳腺癌细胞生长的抑制作用

旨在评估茶氨酸（T）和本实验室合成的新颖的茶氨酸衍生物-茶氨酸氯香酰胺（TClC）对高转移的人乳腺癌MDA-MB-231细胞生长的抑制作用,并对其作用的机制进行初步探究。采用MTT法检测不同浓度的T和TClC对MDA-MB-231细胞体外生长的影响,采用Western blotting对MDA-MB-231细胞中与癌细胞凋亡相关蛋白的表达以及药物作用可能的分子靶点进行检测。结果显示,随着浓度的增高,T和TClC对人乳腺癌MDA-MB-231细胞体外生长的抑制作用逐渐增强, TClC的抑制作用要明显强于T;T和TClC均能够下调抗凋亡蛋白Bcl-2的表达水平,同时上调促凋亡蛋白Bax的表达水平,使Bcl-2/Bax比率减少。此外,T和TClC均能抑制血管内皮生长因子受体VEGFR1和核转录因子NF-κB的表达, 而TClC的抑制作用要明显强于T。T和TClC对这些蛋白水平的调节作用可能是抑制MDA-MB-231细胞生长的重要机制之一。这些结果表明,T和TClC对治疗高转移的人乳腺癌可能具有广阔的应用前景。     

Abnormal cytokinesis in cells deficient in the breast cancer susceptibility protein BRCA2

Germ-line mutations inactivating BRCA2 predispose to cancer. BRCA2-deficient cells exhibit alterations in chromosome number (aneuploidy), as well as structurally aberrant chromosomes. Here, we show that BRCA2 deficiency impairs the completion of cell division by cytokinesis. BRCA2 inactivation in murine embryo fibroblasts (MEFs) and HeLa cells by targeted gene disruption or RNA interference delays and prevents cell cleavage. Impeded cell separation is accompanied by abnormalities in myosin II organization during the late stages in cytokinesis. BRCA2 may have a role in regulating these events, as it localizes to the cytokinetic midbody. Our findings thus link cytokinetic abnormalities to a hereditary cancer syndrome characterized by chromosomal instability and may help to explain why BRCA2-deficient tumors are frequently aneuploid.     

Breast and ovarian cancer risks due to inherited mutations in BRCA1 and BRCA2

Risks of breast and ovarian cancer were determined for Ashkenazi Jewish women with inherited mutations in the tumor suppressor genes BRCA1 and BRCA2. We selected 1008 index cases, regardless of family history of cancer, and carried out molecular analysis across entire families. The lifetime risk of breast cancer among female mutation carriers was 82%, similar to risks in families with many cases. Risks appear to be increasing with time: Breast cancer risk by age 50 among mutation carriers born before 1940 was 24%, but among those born after 1940 it was 67%. Lifetime risks of ovarian cancer were 54% for BRCA1 and 23% for BRCA2 mutation carriers. Physical exercise and lack of obesity in adolescence were associated with significantly delayed breast cancer onset.     

Role of the kinase MST2 in suppression of apoptosis by the proto-oncogene product Raf-1

The ablation of the protein kinase Raf-1 renders cells hypersensitive to apoptosis despite normal regulation of extracellular signal-regulated kinases, which suggests that apoptosis protection is mediated by a distinct pathway. We used proteomic analysis of Raf-1 signaling complexes to show that Raf-1 counteracts apoptosis by suppressing the activation of mammalian sterile 20-like kinase (MST2). Raf-1 prevents dimerization and phosphorylation of the activation loop of MST2 independently of its protein kinase activity. Depletion of MST2 from Raf-1-/- mouse or human cells abrogated sensitivity to apoptosis, whereas overexpression of MST2 induced apoptosis. Conversely, depletion of Raf-1 from Raf-1+/+ mouse or human cells led to MST2 activation and apoptosis. The concomitant depletion of both Raf-1 and MST2 prevented apoptosis.     

A novel nuclear form of estradiol receptor in MCF-7 human breast cancer cells

Nuclear estrogen receptor from MCF-7 cells undergoes a time-dependent, hormone-inducible transformation to a form that is less extractable from nuclei and less exchangeable with ligand. This receptor-modifying, intranuclear event is independent of receptor loss (processing) and appears associated with hormone responsiveness (progesterone-receptor induction) in these cells. The magnitude of receptor loss, however, is variable and apparently not a prerequisite for hormone action to induce progesterone receptor.     

Inheritance of proliferative breast disease in breast cancer kindreds

Previous studies have emphasized that genetic susceptibility to breast cancer is rare and is expressed primarily as premenopausal breast cancer, bilateral breast cancer, or both. Proliferative breast disease (PBD) is a significant risk factor for the development of breast cancer and appears to be a precursor lesion. PBD and breast cancer were studied in 103 women from 20 kindreds that were selected for the presence of two first degree relatives with breast cancer and in 31 control women. Physical examination, screening mammography, and four-quadrant fine-needle breast aspirates were performed. Cytologic analysis of breast aspirates revealed PBD in 35% of clinically normal female first degree relatives of breast cancer cases and in 13% of controls. Genetic analysis suggests that genetic susceptibility causes both PBD and breast cancer in these kindreds. This study supports the hypothesis that this susceptibility is responsible for a considerable portion of breast cancer, including unilateral and postmenopausal breast cancer.     

转染抑癌基因PTEN对人乳腺癌ZR-75-1细胞的细胞周期和增殖能力的影响

目的：观察PTEN（phosphatase and tensin homology deleted on chromosome ten，第10号染色体上磷酸酶和张力蛋白同源缺失的基因）对人乳腺癌细胞ZR-75-1细胞增殖和细胞周期的影响。方法；利用脂质体介导法将携带有野生型和突变型PTEN cDNA的真核表达载体pBP—wt—PTEN和pBP—G129R—PTEN导八人乳腺癌ZR-75-1细胞（质粒转染成功后实验分为C—WT—PTEN组、CG129R—PTEN组和未转染质粒组即对照组）后，以RT—PCR、Western blot分析目的基因的表达，并采用MTT法和流式细胞术检测细胞增殖和细胞周期。结果：C—WT—PTEN组、C—G129R—PTEN组细胞PTEN mRNA及PTEN蛋白出现明显的高表达。C—WT—PTEN组细胞生长的抑制率可高达42．7％，与对照组比较．差异有显著性（P〈0．05）。但C—G129R—PTEN组细胞生长的抑制率与对照组比较，差异无显著性（P〉0．05）。流式细胞术显示C—WT—PTEN组细胞周期从G1期到S期已发生抑制。结论：野生型PTEN可依赖其磷酸酶活性抑制肿瘤细胞的增殖,并最终诱导细胞凋亡。     

Mutational inactivation of STAG2 causes aneuploidy in human cancer

Most cancer cells are characterized by aneuploidy, an abnormal number of chromosomes. We have identified a clue to the mechanistic origins of aneuploidy through integrative genomic analyses of human tumors. A diverse range of tumor types were found to harbor deletions or inactivating mutations of STAG2, a gene encoding a subunit of the cohesin complex, which regulates the separation of sister chromatids during cell division. Because STAG2 is on the X chromosome, its inactivation requires only a single mutational event. Studying a near-diploid human cell line with a stable karyotype, we found that targeted inactivation of STAG2 led to chromatid cohesion defects and aneuploidy, whereas in two aneuploid human glioblastoma cell lines, targeted correction of the endogenous mutant alleles of STAG2 led to enhanced chromosomal stability. Thus, genetic disruption of cohesin is a cause of aneuploidy in human cancer.     

Studies of the human c-myb gene and its product in human acute leukemias

The myb gene is the transforming oncogene of the avian myeloblastosis virus (AMV); its normal cellular homolog, c-myb, is conserved across a broad span of evolution. In humans, c-myb is expressed in malignant hematopoietic cell lines and in primary hematopoietic tumors. Partial complementary DNA clones were generated from blast cells of patients with acute myelogenous leukemia. The sequences of the clones were compared to the c-myb of other species, as well as the v-myb of AMV. In addition, the carboxyl terminal region of human c-myb was placed in an expression vector to obtain protein for the generation of antiserum, which was used to identify the human c-myb gene product. Like v-myb, this protein was found within the nucleus of leukemic cells where it was associated with the nuclear matrix. These studies provide further evidence that c-myb might be involved in human leukemia.