乳腺癌干细胞和乳腺癌

肿瘤干细胞既包含干细胞的特性也包含肿瘤细胞的特性。乳腺癌起源于乳腺癌干细胞的说法能够合理地解释乳腺癌的不均一性及其治疗后的复发,这些变异的干细胞可能作为肿瘤预防策略的靶标。而且,由于乳腺癌干细胞能够抵抗辐射治疗和化学治疗,所以要想更好地治疗乳腺癌就需要寻找针对这些干细胞的靶标。我们综述了乳腺癌干细胞的发现、富集和分离、相关的信号途径,以及在乳腺癌治疗中的应用。     

SUMO与乳腺癌

小泛素修饰物（Small ubiquitin-like modifier,SUMO）是结构上与泛素类似的一种修饰蛋白,能与一些特定的靶蛋白共价连接。与泛素介导蛋白质的降解不同,SUMO化修饰调控主要对靶蛋白的功能,如在蛋白质的稳定性、细胞定位、信号转导、基因转录调控等方面均发挥着重要的作用。最近的研究表明：SUMO与乳腺癌的发生发展密切相关,它是通过SUMO化修饰参与并影响雌激素受体信号通路来实现的,本文将就此做一综述。     

鼠源性人乳腺癌单链抗体库的构建与乳腺癌相关抗体的筛选

目的:获得乳腺癌的噬菌体呈现型单链抗体(scFv)库,筛选与乳腺癌细胞特异结合的抗体,为乳腺癌的诊断和治疗奠定基础。方法:用乳腺癌细胞系MCF-7、T47D、MDA-MB-435免疫BALB/c小鼠,取脾脏提取总RNA,用RT-PCR分别扩增抗体重、轻链可变区(VH和VL)基因,经Linker连接形成scFv基因片段。将scFv基因片段与噬菌粒载体pCANTAB5E的连接产物转化大肠杆菌TG1。用辅助噬菌体M13KO7进行超感染,获得重组噬菌体抗体。选用乳腺癌细胞系MCF-7和人正常肝细胞系HL02做正负差异的筛选细胞,通过5轮筛选,随机挑取克隆,经phage-ELISA筛选特异性结合MCF-7细胞的scFv。结果:构建了1个库容为1.3×106的单链抗体库。筛选到2株与MCF-7细胞有较高结合活性的噬菌体-单链抗体scFv-873和scFv-874。数据库搜索表明这2株单链抗体基因是与以往抗体序列不同的新基因。用Westernblot检测了这2株单链抗体在琥珀密码子非抑制型菌株TOP10中的表达情况。结论:筛选到2个与乳腺癌细胞结合特异性较好的单链抗体,为乳腺癌的诊断和治疗研究奠定了基础。     

The landscape of mitochondrial DNA variation in human colorectal cancer on the background of phylogenetic knowledge

Recently, an increasing number of studies indicate that mutations in mitochondrial genome may contribute to cancer development or metastasis. Hence, it is important to determine whether the mitochondrial DNA might be a good, clinically applicable marker of cancer. This review describes hereditary as well as somatic mutations reported in mitochondrial DNA of colorectal cancer cells. We showed here that the entire mitochondrial genome mutational spectra are different in colorectal cancer and non-tumor cells. We also placed the described mutations on the phylogenetic context, which highlighted the recurrent problem of data quality. Therefore, the most important rules for adequately assessing the quality of mitochondrial DNA sequence analysis in cancer have been summarized. As follows from this review, neither the reliable spectrum of mtDNA somatic mutations nor the association between hereditary mutations and colorectal cancer risk have been resolved. This indicates that only high resolution studies on mtDNA variability, followed by a proper data interpretation employing phylogenetic knowledge may finally verify the utility of mtDNA sequence (if any) in clinical practice.     

窖蛋白-1与乳腺癌

 窖蛋白(caveolin)是分子量为21～24 kD的整合膜蛋白,是胞膜窖(caveolae)的标志性结构分子.目前已克隆并鉴定出窖蛋白基因家族的3个成员：窖蛋白-1,窖蛋白-2和窖蛋白-3.其中窖蛋白-1参与细胞内的许多生命活动,如胆固醇的运输,细胞膜的组装,细胞信号传导,细胞周期调控,细胞转化和肿瘤形成.窖蛋白-1还可以与转录因子相互作用,调节相关基因的表达,抑制肿瘤发生.另外,在乳腺癌、前列腺癌、胃癌、肝癌等多种恶性肿瘤中均发现窖蛋白-1的异常;近年来发现,窖蛋白-1与乳腺上皮细胞转化和乳腺癌发生密切相关.本文概括介绍了窖蛋白-1的结构特点、窖蛋白-1介导的信号通路及与乳腺癌发生的关系方面的研究进展.     

T型钙通道与乳腺癌

T型钙通道是激活电位低、失活速度快、单通道电导小的电压依赖性钙通道,具有高组织特异性、突出的生理功能及药理学选择性等特点。近年来的研究表明,T型钙通道通过独特的激活失活效应参与细胞内外钙流的振荡,影响肿瘤细胞的增殖过程。值得关注的是正常人乳腺上皮细胞中没有T型钙通道,而在不同分化阶段的乳腺癌细胞中该通道却有表达。实验证实,T型钙通道的表达影响乳腺癌细胞的增殖,通道拮抗剂能够显著地抑制乳腺癌细胞增殖。这一发现为乳腺癌的诊断及靶向治疗药物的研发提供了新的思路。本文概要介绍了近年来T型钙通道与乳腺癌关系的研究进展。     

乳腺癌易感基因突变的狭窄分布及其人群差异性

最近10多年来,包括最重要的BRCA1/2在内的多种女性乳腺癌发生发展相关易感基因获得鉴定,并依据其肿瘤风险相关性程度被分别归入高、中和低外显率组别.随后它们的遗传学变异及致病机制研究在世界范围内得以广泛深入地开展,并揭示出其胚系突变具有人群或地域差异性,且局限于仅占10%~20%家族遗传性和早发性乳腺癌的狭窄分布概貌.这些结果转而提示对于大量散发性乳腺癌发病分子机制的研究而言,必须更深入地探讨多重低风险易感多态性复合效应的影响.     

新型雌激素受体ER-α36与乳腺癌

雌激素受体(estrogen receptor,ER)是诊断和治疗乳腺癌的分子标志和靶点.雌激素受体包括ER-α和ER-β,其中ER-α有ER-α66、ER-α46和ER-α36三种亚型.ER-α36作为新型雌激素受体,参与膜起始的雌激素信号或非基因组雌激素信号转导,在肿瘤细胞的增殖、分化、侵袭和转移等过程中发挥作用.胃癌、子宫内膜腺癌、前列腺癌、尤其是乳腺癌的发生发展与ER-α36密切相关.本文介绍了ER-α36的结构域特点,ER-α36介导的信号通路及ER-α36在乳腺癌治疗中的作用研究进展.     

乳腺癌蛋白质组学研究

乳腺癌是妇女中最常见的一种癌症,鉴定出与乳腺癌癌变相关的蛋白质以及病情发展过程中蛋白质的变化对揭示乳腺癌变机理及早期诊断是非常重要的。早在蛋白质组学这一概念提出以前,人们已应用2－维凝胶电泳技术（2DE）研究乳腺癌的癌变机理,且随着人类基因序列测序的完成,质谱的应用,以及生物信息学的引入,蛋白质组的研究获得了飞速发展,高通量的蛋白质组研究以及新的技术如激光捕获显微切割（LCM）,表面加强激光解吸／电离飞行时间质谱（SELDI－TOF）,蛋白质阵列,组织阵列等蛋白质组学技术已被用于乳腺癌研究并获得了很快速的发展。乳腺癌蛋白质组学研究已经鉴定了一些具有诊断潜能的生物分子靶标和信号传导因子。介绍了乳腺癌蛋白质组学研究中所使用的最新研究方法和研究进展。     

Mitochondria: Biogenesis and mitophagy balance in segregation and clonal expansion of mitochondrial DNA mutations

Mitochondria are cytoplasmic organelles containing their own multi-copy genome. They are organized in a highly dynamic network, resulting from balance between fission and fusion, which maintains homeostasis of mitochondrial mass through mitochondrial biogenesis and mitophagy. Mitochondrial DNA (mtDNA) mutates much faster than nuclear DNA. In particular, mtDNA point mutations and deletions may occur somatically and accumulate with aging, coexisting with the wild type, a condition known as heteroplasmy. Under specific circumstances, clonal expansion of mutant mtDNA may occur within single cells, causing a wide range of severe human diseases when mutant overcomes wild type. Furthermore, mtDNA deletions accumulate and clonally expand as a consequence of deleterious mutations in nuclear genes involved in mtDNA replication and maintenance, as well as in mitochondrial fusion genes (mitofusin-2 and OPA1), possibly implicating mtDNA nucleoids segregation. We here discuss how the intricacies of mitochondrial homeostasis impinge on the intracellular propagation of mutant mtDNA.This article is part of a Directed Issue entitled: Energy Metabolism Disorders and Therapies.     

Analysis of Gut Microbiota in Patients with Breast Cancer and Benign Breast Lesions

Breast cancer (BC) and benign breast lesions (BBLs) are common diseases in women worldwide. The gut microbiota plays a vital role in regulating breast diseases’ formation, progression, and therapy response. Hence, we explored the structure and function of gut microflora in patients with BC and BBLs. A cohort of 66 subjects was enrolled in the study. Twenty-six subjects had BC, 20 subjects had BBLs, and 20 matched healthy controls. High throughput 16S ribosomal RNA (16S rRNA) gene sequencing technology was used to determine the microbial community structure. Compared with healthy individuals, BC patients had significantly lower alpha diversity indices (Sobs index, p = 0.019; Chao1 index, p = 0.033). Sobs and Chao1 indices were also lower in patients with BBLs than healthy individuals, without statistical significance (p = 0.279, p = 0.314, respectively). Both unweighted and weighted UniFrac analysis showed that beta diversity differed significantly among the three groups (p = 3.376e–14, p < 0.001, respectively). Compared with healthy individuals, the levels of Porphyromonas and Peptoniphilus were higher in BC patients (p = 0.004, p = 0.007, respectively), whereas Escherichia and Lactobacillus were more enriched in the benign breast lesion group (p < 0.001, p = 0.011, respectively). Our study indicates that patients with BC and BBLs may undergo significant changes in intestinal microbiota. These findings can help elucidate the role of intestinal flora in BC and BBLs patients. Open in a separate window     

Mitochondria,oxidative stress and aging

In the eighties, Miquel and Fleming suggested that mitochondria play a key role in cellular aging. Mitochondria, and specially mitochondrial DNA (mtDNA), are major targets of free radical attack. At present, it is well established that mitochondrial deficits accumulate upon aging due to oxidative damage. Thus, oxidative lesions to mtDNA accumulate with age in human and rodent tissues. Furthermore, levels of oxidative damage to mtDNA are several times higher than those of nuclear DNA. Mitochondrial size increases whereas mitochondrial membrane potential decreases with age in brain and liver.

Recently, we have shown that treatment with certain antioxidants, such as sulphur-containing antioxidants, vitamins C and E or the Ginkgo biloba extract EGb 761, protects against the age-associated oxidative damage to mtDNA and oxidation of mitochondrial glutathione. Moreover, the extract EGb 761 also prevents changes in mitochondrial morphology and function associated with aging of the brain and liver. Thus, mitochondrial aging may be prevented by antioxidants. Furthermore, late onset administration of certain antioxidants is also able to prevent the impairment in physiological performance, particularly motor co-ordination, that occurs upon aging.     

Presence of Human Papillomavirus DNA in Malignant Neoplasia and Non-Malignant Breast Disease

Breast cancer is the leading cause of cancer death among women worldwide. Multiple extrinsic and intrinsic factors are associated with this disease’s development. Various research groups worldwide have reported the presence of human papillomavirus (HPV) DNA in samples of malignant breast tumors. Although its role in mammary carcinogenesis is not fully understood, it is known that the HPV genome, once inserted into host cells, has oncogenic capabilities. The present study aimed to detect the presence of HPV DNA in 116 breast tissue biopsies and classify them according to their histology. It was found that 50.9% of the breast biopsies analyzed were malignant neoplasms, of which 74.6% were histologically classified as infiltrating ductal carcinoma. In biopsies with non-malignant breast disease, fibroadenoma was the most common benign neoplasm (39.1%). Detection of HPV DNA was performed through nested PCR using the external primer MY09/11 and the internal primer GP5+/6+. A hybridization assay genotyped HPV. HPV DNA was identified in 20.3% (12/59) of malignant neoplasms and 35% non-malignant breast disease (16/46). It was also detected in 27.3% (3/11) of breast tissue biopsies without alteration. However, there are no statistically significant differences between these groups and the existence of HPV DNA (p = 0.2521). Its presence was more frequent in non-malignant alterations than in malignant neoplasias. The most frequent genotypes in the HPV-positive samples were low-risk (LR) HPV-42 followed by high-risk (HR) HPV-31.     

DNA methylation and breast tumor clinicopathological features: The Western New York Exposures and Breast Cancer (WEB) study

We evaluated the association between methylation of 9 genes, SCGB3A1, GSTP1, RARB, SYK, FHIT, CDKN2A, CCND2, BRCA1, and SFN in tumor samples from 720 breast cancer cases with clinicopathological features of the tumors and survival. Logistic regression was used to estimate odds ratios (OR) of methylation and Cox proportional hazards models to estimate hazard ratios (HR) between methylation and breast cancer related mortality. Estrogen receptor (ER) and progesterone receptor (PR) positivity were associated with increased SCGB3A1 methylation among pre- and post-menopausal cases. Among premenopausal women, compared with Stage 0 cases, cases of invasive cancer were more likely to have increased methylation of RARB (Stage I OR = 4.7, 95% CI: 1.1–19.0; Stage IIA/IIB OR = 9.7, 95% CI: 2.4–39.9; Stage III/IV OR = 5.6, 95% CI: 1.1–29.4) and lower methylation of FHIT (Stage I OR = 0.2, 95% CI: 0.1–0.9; Stage IIA/IIB OR = 0.2, 95% CI: 0.1–0.8; Stage III/IV OR = 0.6, 95% CI: 0.1–3.4). Among postmenopausal women, methylation of SYK was associated with increased tumor size (OR = 1.7, 95% CI: 1.0–2.7) and higher nuclear grade (OR = 2.0, 95% CI 1.2–3.6). Associations between methylation and breast cancer related mortality were observed among pre- but not post-menopausal women. Methylation of SCGB3A1 was associated with reduced risk of death from breast cancer (HR = 0.41, 95% CI: 0.17–0.99) as was BRCA1 (HR = 0.41, 95% CI: 0.16–0.97). CCND2 methylation was associated with increased risk of breast cancer mortality (HR = 3.4, 95% CI: 1.1–10.5). We observed differences in methylation associated with tumor characteristics; methylation of these genes was also associated with breast cancer survival among premenopausal cases. Understanding of the associations of DNA methylation with other clinicopathological features may have implications for prevention and treatment.     

成骨细胞特异性转录因子2与乳腺癌

Runx2为成骨细胞特异性转录因子,调控成骨细胞分化和骨组织的形成.近年来研究表明,Runx2在乳腺癌中可以激活与癌症转移相关的骨基质、黏附蛋白、金属蛋白酶以及血管内皮生长因子,并且Runx2可以与一些联合抑制剂或激活剂形成调控复合体,在亚核结构域中存在,调节基因的转录以及间接地影响乳腺癌细胞的信号通路.除此之外,Runx2还可以与雌激素受体相互作用在某种程度上解除雌激素及其受体在乳腺癌发展中的调控作用.本文主要概括Runx2在乳腺癌中的作用机制,重点综述Runx2在乳腺癌中与雌激素受体相互作用的研究进展.     

Hedgehog信号通路与乳腺癌

近年来的研究表明,Hedgehog信号通路在肿瘤的发生发展中具有重要的作用,该通路基因突变或异常表达将导致多种器官肿瘤的发生,并与Wnt、MAPK等信号通路相互作用,共同调节肿瘤的发生发展。我们简要综述了Hedgehog信号通路在乳腺癌发生发展中的重要作用,旨在了解乳腺癌发生、发展的分子机制.     

C-Erbb-2 Expression and Dna Ploidy Status In Breast Cancer Cells Obtained By Fine Needle Aspiration (Fna)

The aim of this study was to determine the relative rate of c-erbB-2 oncoprotein immuno-detection on matched fine needle aspiration (FNA) smears and surgical specimens of breast cancer, and to correlate the c-erbB-2 expression with the assessment of the DNA ploidy status. the expression of c-erbB-2 oncoprotein was evaluated using an immunoalkaline phosphatase technique in 49 breast aspirates (four benign and 45 malignant lesions) and 21 matched surgical specimens. the DNA ploidy status was assessed by densitometric techniques on Feulgen-stained smears. Fifty-eight per cent of the smears obtained from 45 malignant lesions and 43% of the 21 corresponding paraffin sections contained cells that were stained by the antibody. the higher incidence of c-erbB-2 expression on smears seems to be due mainly to the better antigen preservation in the fresh cytological preparations. the correlation between c-erbB-2 oncogene expression and DNA ploidy assessment showed an increased incidence of oncogene expression in aneuploid tumours (71% vs 29%; P > 0.05).