HER-2-Positive Breast Cancer

Therapeutic antibodies have shown great promise as targeted agents in the treatment of patients with cancer. Trastuzumab, a humanized monoclonal antibody targeting human epidermal growth factor receptor-2 (HER-2), is of special importance in breast cancers overexpressing HER-2. Such rationally designed substances bind to cancer cells expressing the targeted antigen and, by various mechanisms, lead to tumor cell degradation. Only one-third of patients, however, initially respond to trastuzumab monotherapy and the majority of initial responders demonstrate disease progression within 1 year of treatment initiation. Therefore, alternative compounds targeting the HER-2 receptor or downstream signaling pathways are of great importance. Lapatinib is a tyrosine kinase inhibitor, blocking tryosine kinase domains of both epidermal growth factor receptor and HER-2. This substance holds promise for the treatment of cancer after trastuzumab failure, and might be active in cerebral metastases. Other strategies in trastuzumab-resistant disease include bispecific antibodies (which bind to HER-2 and Fc receptors, thereby directing immune cells towards the tumor), the combination of antibodies, or targeting tumor vessel growth by blocking vascular endothelial growth factor (VEGF) or VEGF receptors. Heat shock protein 90, a chaperone protein that controls the folding of HER-2, also represents a potential target. Multi-targeted kinase inhibitors such as sunitinib or sortenib are already established in renal cell cancer. These compounds are currently being evaluated in breast cancer and might represent interesting options both in HER-2-positive and -negative disease. In conclusion, trastuzumab remains the gold standard in HER-2-positive breast cancer therapy. However, in trastuzumab-resistant disease, new strategies and compounds are currently under evaluation.     

SRL172 (killed Mycobacterium vaccae) may augment the efficacy of trastuzumab in metastatic breast cancer patients

SRL172, non-specific immunological adjuvant downregulates interleukin-4, upregulates interleukin-2 production, switching towards a T-helper-1 response, induces an increase in natural killer cells and activates antigen presenting cells. The human epidermal growth factor receptor 2 gene amplification is frequently observed in a number of primary tumors, suggesting that the overexpression of this growth factor receptor may contribute to transformation and tumorigenesis. Gene amplification occurs in approximately 15-20% of human breast cancers Amplification is associated with aggressive tumor behavior and shortened survival. Trastuzumab, humanized anti-HER-2 antibody targets the HER-2 protein with high affinity. Trastuzumab when used alone or in combination with cytotoxic chemotherapy can induce reasonably durable remissions in a significant percentage of women with metastatic breast cancer whose tumors demonstrate Her-2/neu gene amplification. One of the proposed mechanisms of trastuzumab antitumor action is through antibody dependent cellular cytotoxocity. Pivotal study showed that Trastuzumab+IL-2 resulted in NK cell expansion with enhanced in vitro targeted killing of HER-2-expressing cells. SRL172 by increasing IL-2 production and number of natural killer cells may augment the efficacy of trastuzumab in metastatic breast cancer patients. SRL 172 increases IL-2 production and the number of NK cells in vivo. Based on these data, a clinical trial can be performed to test whether SRL 172 added to trastuzumab is safe and more efficacious.     

In vivo expansion of hemopoietic stem cells

Under conditions of steady-state hemopoiesis, a small fraction of immature hemopoietic cells, including stem cells, circulates in peripheral blood (PB). In rhesus monkeys, a median number of 1.2 x 10(7)/l CD34+ cells was observed as opposed to a median number of 1.5 x 10(9)/l in aspirated bone marrow (BM). The concentration of circulating CD34+ cells is therefore approximately two logs less than that in BM. Since a 4-kg rhesus monkey has an estimated number of 3 x 10(10) BM cells and approximately 300 ml of blood, the fraction of CD34+ cells that circulates can be estimated at approximately 0.4% of the total pool of CD34+ cells. During hemopoietic reconstitution following a cytotoxic insult such as results from a midlethal dose of TBI, PB CD34+ cell numbers appeared to be correlated to those of BM, suggesting that PB CD34+ cells may reflect reconstitution of BM CD34+ cells. Reconstitution of BM immature cells can be accelerated by treatment with pharmacological doses of growth factors, resulting in largely expanded immature cell populations within a few weeks after TBI. Growth factors observed to exert such an effect included, notably, thrombopoietin. Such an acceleration can be monitored by daily assessment of circulating CD34+ cells. Expansion of immature circulating cells indicates expansion of similar cells in the bone marrow rather than growth factor-induced selective mobilization of immature cells.     

Adjuvant targeted therapy with trastuzumab may decrease metastatic capacity in specific group of oropharyngeal cancer patients: downregulation of E-cadherin-catenin complex by cooperative effect of erbB-2 and human papillomavirus type 16 E6/E7 protooncogenes

Human papillomavirus (HPV) type 16 is causally associated with a subset of oral cancers, predominantly those cancers arising in the oropharynx (OP). Increased HPV16 E6 and E7 oncogene expressions are responsible for the malignant transmission in these cancers. ErbB-2 is the family member most closely implicated in human cancer, where it is overexpressed in about 30% of carcinomas including head and neck squamous cell carcinoma. Coexpressions of E6/E7 and ErbB-2 downregulate E-cadherin and catenin expression, therefore induces metastatic process. Trastuzumab is a humanized monoclonal antibody that recognizes the ErbB-2 protein receptor and breakthrough in the treatment of metastatic breast cancer in combination with chemotherapeutic agents. This antibody is also in clinical testing for adjuvant treatment of breast cancer. We propose that trastuzumab as an adjuvant treatment may decrease process of tumor metastasis in oropharyngeal cancer patients who completed primary treatment (surgery and/or radiotherapy) and show expression of both HPV16 E6/E7 and erbB-2 oncoproteins. In vitro and in vivo studies with trastuzumab in these subgroup of patients may support our hypothesis.     

Micropapillary Carcinoma of the Breast with Necrosis-like Cell Death: A Case Report

A primary invasive micropapillary carcinoma of the breast in a 46-year-old woman is reported. Histologically, it was composed predominantly of papillary tumor cell clusters without fibrovascular cores, surrounded by a clear space. Tumor cells were positive for cytokeratin (CK) 7, estrogen receptor (ER), and progesterone receptor (PR), but negative for p53, CK 20, CD34, c-Erb-B2, CK5, epidermal growth factor receptor (EGFR), vimentin, and c-kit. MUC1 expression was found at the reversed apical membrane of neoplastic cell clusters. Accordingly, electron microscopy showed the lack of basement membrane and presence of microvilli at the basal surface of the tumor cells. Moreover, ultrastructural examination revealed single tumor cell death characterized by patchy condensations of chromatin throughout the nucleus. These nuclear alterations were associated with the occurrence of empty cytoplasmic vacuoles, conferring a necrosis-like phenotype to this cell death. Alternative programmed cell deaths are reviewed and their morphologic distinction is discussed.     

Micropapillary carcinoma of the breast with necrosis-like cell death: a case report

A primary invasive micropapillary carcinoma of the breast in a 46-year-old woman is reported. Histologically, it was composed predominantly of papillary tumor cell clusters without fibrovascular cores, surrounded by a clear space. Tumor cells were positive for cytokeratin (CK) 7, estrogen receptor (ER), and progesterone receptor (PR), but negative for p53, CK 20, CD34, c-Erb-B2, CK5, epidermal growth factor receptor (EGFR), vimentin, and c-kit. MUC1 expression was found at the reversed apical membrane of neoplastic cell clusters. Accordingly, electron microscopy showed the lack of basement membrane and presence of microvilli at the basal surface of the tumor cells. Moreover, ultrastructural examination revealed single tumor cell death characterized by patchy condensations of chromatin throughout the nucleus. These nuclear alterations were associated with the occurrence of empty cytoplasmic vacuoles, conferring a necrosis-like phenotype to this cell death. Alternative programmed cell deaths are reviewed and their morphologic distinction is discussed.     

Focal adhesion kinase-related proline-rich tyrosine kinase 2 and focal adhesion kinase are co-overexpressed in early-stage and invasive ErbB-2-positive breast cancer and cooperate for breast cancer cell tumorigenesis and invasiveness

Early cancer cell migration and invasion of neighboring tissues are mediated by multiple events, including activation of focal adhesion signaling. Key regulators include the focal adhesion kinase (FAK) and FAK-related proline-rich tyrosine kinase 2 (Pyk2), whose distinct functions in cancer progression remain unclear. Here, we compared Pyk2 and FAK expression in breast cancer and their effects on ErbB-2-induced tumorigenesis and the potential therapeutic utility of targeting Pyk2 compared with FAK in preclinical models of breast cancer. Pyk2 is overexpressed in tissues from early and advanced breast cancers and overexpressed with both FAK and epidermal growth factor receptor-2 (ErbB-2) in a subset of breast cancer cases. Down-regulation of Pyk2 in ErbB-2-positive, FAK-proficient, and FAK-deficient cells reduced cell proliferation, which correlated with reduced mitogen-activated protein kinase (MAPK) activity. In contrast, Pyk2 silencing had little impact on cell migration and invasion. In vivo, Pyk2 down-regulation reduced primary tumor growth induced by a metastatic variant of ErbB-2-positive MDA 231 breast cancer cells but had little effect on lung metastases in contrast to FAK down-regulation. Dual reduction of Pyk2 and FAK expression resulted in strong inhibition of both primary tumor growth and lung metastases. Together, these data support the cooperative function of Pyk2 and FAK in breast cancer progression and suggest that dual inhibition of FAK and Pyk2 is an efficient therapeutic approach for targeting invasive breast cancer.     

Abnormal Hemopoiesis in Long-Term Bone Marrow Culture from Tumor Necrosis Factor-Deficient Mice

We studied hemopoiesis in mice deficient by the tumor necrosis factor gene. The total number of cells in long-term bone marrow cultures from these mice 2-fold surpassed that in wild-type and tumor necrosis factor p55 receptor-deficient animals. Increased cell production was related to the absence of tumor necrosis factor expression by hemopoietic precursors. The total cell production by explanted hemopoietic cells from tumor necrosis factor-deficient mice did not depend on the genotype of irradiated stromal sublayer in long-term cell cultures from wild-type mice and animals deficient by tumor necrosis factor or p55 receptor. These results suggest that tumor necrosis factor, but not its p55 receptor, is involved in transduction of signals regulating production of cultured cells. Tumor necrosis factor probably regulates hemopoiesis in long-term bone marrow cultures by initiating apoptosis of hemopoietic cells or inhibiting cell proliferation. Increased cell production probably attests to the absence of one or both effects.     

肝癌干细胞分离及其细胞生物学特性

背景：正常干细胞和肿瘤干细胞在基因表达和依赖的细胞信号通路上应该存在不同,如何发现能选择性杀伤肿瘤干细胞的治疗手段是一个仍然需要大量研究的课题。 目的：分离人肝癌细胞系肿瘤干细胞MHCC97,分析其细胞生物学特性。 方法：采用流式细胞技术在人高转移肝癌细胞系MHCC97中筛选肿瘤干细胞,分离正常人肝脏干细胞CD133^-CD34^- MHCC97和人肝癌细胞系肿瘤干细胞CD133⁺CD34⁺ MHCC97,分别检测其表型、生长曲线、细胞周期和多系分化能力。 结果与结论：人肝癌细胞系CD133⁺CD34⁺ MHCC97肿瘤干细胞的表型为CD133⁺CD34⁺ ,人肝癌细胞系CD133⁺CD34⁺ MHCC97具有与CD133^-CD34^- MHCC97相似的细胞曲线和生长周期,可以向上皮和内皮细胞分化,并表达相应特异性的分子标志。提示人肝癌细胞系中CD133⁺CD34⁺MHCC97细胞具有肿瘤干细胞的特性,可以向内皮和上皮细胞分化,同时具有肿瘤干细胞的生物学特性,是肿瘤复发转移的根源,也是临床治疗的靶点。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

Derivation of endothelial cells from CD34- umbilical cord blood

CD34 is a transmembrane glycoprotein constitutively expressed on endothelial cells and hematopoietic stem cells. Use of CD34-recognizing antibodies has helped in the identification and isolation of CD34+ endothelial precursors from embryonic and adult tissues. However, CD34-null mice display no vascular abnormalities, demonstrating that CD34 antigen expression is not required for normal vascular development. Here we show that a CD34- cell population that includes endothelial cell precursors can be isolated from cord blood. In the presence of angiogenic factors, these cells mature to express the endothelial cell markers vascular endothelial-cadherin, vascular endothelial growth factor receptor-1 and -2, Tie-1 and -2 (tyrosine kinase with immunoglobulin and epidermal growth factor homology domains), von Willebrand factor, and CD31 while maintaining their CD34- status, and can be expanded in vitro for over 20 passages. Moreover, in functional studies, these cells can undergo extracellular matrix-dependent morphogenic changes into capillary-like tubular structures. When transplanted into immunodeficient mice in conjunction with tumor cells or with the proangiogenic factor basic fibroblast growth factor, these cells can form functional microvessels arising along with host blood cells. These studies provide strong evidence for the existence of CD34- endothelial cell precursors in cord blood and suggest the use of ex vivo-expanded cord blood CD34- cells as a unique tool for the investigation of postnatal lineage diversification.     

Hierarchy of Stroma-derived Factors in Supporting Growth of Stroma-dependent Hemopoietic Cells: Membrane-bound SCF is Sufficient to Confer Stroma Competence to Epithelial Cells

Hemopoiesis takes place in a microenvironment where hemopoietic cells are closely associated with stroma by various interactions. Stroma coregulates the proliferation and differentiation of hemopoietic cells. Stroma-hemopoietic-cell contact can be supported by locally produced membrane associated growth factors. The stroma derived growth factor, stem cell factor (SCF) is important in hemopoiesis. We examined the different biological interactions of membrane bound and soluble SCF with human hemopoietic cells expressing the SCF receptor, c-kit. To analyze the function of the SCF isoforms in inducing the proliferation of hemopoietic TF1 or Cord blood (CB) CD34 + cells we used stroma cell lines that differ in their presentation of no SCF, membrane SCF, or soluble SCF. We established a new coculture system using an epithelial cell line that excludes potential interfering effects with other known stroma encoded hemopoietic growth factors. We show that soluble SCF, in absence of membrane-bound SCF, inhibits long term clonal growth of primary or established CD34 + hemopoietic cells, whereas membrane-inserted SCF "dominantly" induces long term proliferation of these cells. We demonstrate a hierarchy of these SCF isoforms in the interaction of stroma with hemopoietic TF1 cells. Membrane-bound SCF is "dominant" over soluble SCF, whereas soluble SCF acts epistatically in interacting with hemopoietic cells compared with other stroma derived factors present in SCF deficient stroma. A hierarchy of stroma cell lines can be arranged according to their presentation of membrane SCF or soluble SCF. In our model system, membrane-bound SCF expression is sufficient to confer stroma properties to an epithelial cell line but soluble SCF does not.     

Hierarchy of stroma-derived factors in supporting growth of stroma-dependent hemopoietic cells: membrane-bound SCF is sufficient to confer stroma competence to epithelial cells

Hemopoiesis takes place in a microenvironment where hemopoietic cells are closely associated with stroma by various interactions. Stroma coregulates the proliferation and differentiation of hemopoietic cells. Stroma-hemopoietic-cell contact can be supported by locally produced membrane associated growth factors. The stroma derived growth factor, stem cell factor (SCF) is important in hemopoiesis. We examined the different biological interactions of membrane bound and soluble SCF with human hemopoietic cells expressing the SCF receptor, c-kit. To analyze the function of the SCF isoforms in inducing the proliferation of hemopoietic TF1 or Cord blood (CB) CD34+ cells we used stroma cell lines that differ in their presentation of no SCF, membrane SCF, or soluble SCF. We established a new coculture system using an epithelial cell line that excludes potential interfering effects with other known stroma encoded hemopoietic growth factors. We show that soluble SCF, in absence of membrane-bound SCF, inhibits long term clonal growth of primary or established CD34+ hemopoietic cells, whereas membrane-inserted SCF "dominantly" induces long term proliferation of these cells. We demonstrate a hierarchy of these SCF isoforms in the interaction of stroma with hemopoietic TF1 cells. Membrane-bound SCF is "dominant" over soluble SCF, whereas soluble SCF acts epistatically in interacting with hemopoietic cells compared with other stroma derived factors present in SCF deficient stroma. A hierarchy of stroma cell lines can be arranged according to their presentation of membrane SCF or soluble SCF. In our model system, membrane-bound SCF expression is sufficient to confer stroma properties to an epithelial cell line but soluble SCF does not.     

EGFR and gastrointestinal stromal tumor: an immunohistochemical and FISH study of 82 cases.

Gastrointestinal stromal tumor is the most common mesenchymal neoplasm of the gastrointestinal tract. Mutually exclusive KIT or platelet-derived growth factor receptor-alpha mutations are key events in gastrointestinal stromal tumor pathogenesis, and specific treatment targeting KIT/platelet-derived growth factor receptor-alpha activation is available. Epidermal growth factor receptor plays an important role in cancer biology and also constitutes a promising molecular target of therapy. Very few reports have been published in the literature about the relationship between gastrointestinal stromal tumor and epidermal growth factor receptor. The aim of this study was to investigate epidermal growth factor receptor immunohistochemical expression and epidermal growth factor receptor gene amplification in 82 consecutive gastrointestinal stromal tumor cases using tissue microarray technique. Hematoxylin- and eosin-stained sections and clinical information were reviewed, and expression of CD117 (KIT), CD34 and epidermal growth factor receptor was investigated by immunohistochemistry. Epidermal growth factor receptor gene copy number was determined using fluorescence in situ hybridization. Immunohistochemistry revealed that CD117 and CD34 were expressed in 96 and 57% of tumors, respectively. Variable epidermal growth factor receptor protein immunohistochemical overexpression was detected in 96% of gastrointestinal stromal tumor cases, but none of the 75 cases with represented tumor tissue cores and countable fluorescence signals exhibited epidermal growth factor receptor gene amplification by fluorescence in situ hybridization. These results show that there is no correlation between epidermal growth factor receptor protein overexpression by immunohistochemistry and epidermal growth factor receptor gene amplification by fluorescence in situ hybridization. Considering that the mechanisms of epidermal growth factor receptor protein overexpression are not well understood and the possibility that anti-epidermal growth factor receptor therapy may be beneficial for patients with gastrointestinal stromal tumor that overexpresses epidermal growth factor receptor, additional studies are encouraged.     

Adherent cells generated during long-term culture of human umbilical cord blood CD34+ cells have characteristics of endothelial cells and beneficial effect on cord blood ex vivo expansion

Hematopoiesis depends on the association of hematopoietic stem cells with stromal cells that constitute the hematopoietic microenvironment. The in vitro development of the endothelial cell from umbilical cord blood (UCB) is not well established and has met very limited success. In this study, UCB CD34(+) cells were cultured for 5 weeks in a stroma-free liquid culture system using thrombopoietin, flt3 ligand, and granulocyte-colony stimulating factor. By week 4-5, we found that firmly adherent fibroblast-like cells were established. These cells showed characteristics of endothelial cells expressing von Willebrand factor, human vascular cell adhesion molecule-1, human intracellular adhesion molecule-1, human CD31, E-selectin, and human macrophage. Furthermore, when comparing an ex vivo system without an established endothelial monolayer to an ex vivo system with an established endothelial monolayer, better expansion of total nucleated cells, CD34(+) cells, and colony-forming units (CFUs)-granulocyte-macrophage and CFUs-granulocyte-erythroid-megakaryocyte-macrophage were found during culture. This phenomenon was in part due to the fact that a significant reduction of apoptotic fractions was found in the CD34(+) cells, which were cultured on the adherent monolayer for up to 5 weeks. To gather quantitative data on the number of endothelial cells derived from a given number of CD34 cells, we performed limiting dilution assay by using Poisson distribution: the number of tested cells (linear scale) producing a 37% negative culture (logarithmic scale) is the number of cells containing one endothelial cell. By this method, one endothelial cell may be found from 314 CD34(+) cells after 5 weeks of culture. These results suggest that the UCB CD34(+) cell fraction contains endothelial cell precursors, establishing the hematopoietic microenvironment and providing the beneficial effects through downregulating apoptosis on UCB expansion protocols. These observations may provide insight for future cellular therapy or graft engineering.     

Isolation and transduction of CD34+ cells from small quantities of peripheral blood from HIV-1-infected patients not treated with hemopoietic growth factors

A proposed hemopoietic stem cell gene therapy for treatment for HIV infection would involve transduction of CD34+ hemopoietic stem cells with vectors encoding anti-HIV constructs. Peripheral blood has proved to be a useful source of these hemopoietic stem cells and this study exploits this finding. Small quantities of peripheral blood were obtained from HIV-negative patients and HIV-positive patients who were and were not receiving hemopoietic growth factors (HGFs). CD34+ cells were obtained from these samples using a simple technique and scored for frequency of colony type. This demonstrated that HIV-negative patients had the highest frequency of colony-forming units (CFUs). HIV-positive patients not treated with HGFs had a lower frequency of CFUs, but the same colony type distribution as HIV-negative patients. HIV-positive patients treated with HGFs had the lowest frequency of CFUs, but their colony type distribution demonstrated that they had responded to treatment. CD34+ cells selected in this way were also transduced with the murine retroviral MFG vector using a technique that demonstrated transduction efficiencies ranging from 2% to 16% (median, 11.5%). This study simplifies the experimental requirements for development of a hemopoietic stem cell gene therapy for HIV infection and offers the possibility that longitudinal studies could be performed on peripheral blood CD34+ cells from HIV-positive or HIV-negative patients without the need for granulocyte colony-stimulating factor mobilization.     

Comparative oncology: ErbB-1 and ErbB-2 homologues in canine cancer are susceptible to cetuximab and trastuzumab targeting

To facilitate comparative oncology trials we compared the biological and molecular homologies of canine (dog; Canis lupus familiaris) and human tumor-associated antigens ErbB-1 and -2. Further, we investigated whether they could serve as targets for anti-ErbB-1 (cetuximab) and anti-ErbB-2 antibodies (trastuzumab), which are highly relevant in human clinical oncology. Immunohistochemistry of canine mammary cancer showed ErbB-1 overexpression in 3/10 patients and ErbB-2 in 4/10. We report 91% amino acid homology for ErbB-1 and 92% for ErbB-2 between canine and human molecules. Modeling of canine on human ErbB-1 revealed that the cetuximab epitope only differs by 4 amino acids: Lys443 is replaced by Arg, Ser468 by Asn, Gly471 by Asp, and Asn473 by Lys in canines. The trastuzumab binding site is identical in human and canine ErbB-2 apart from a single amino acid change (Pro557 to Ser). Binding of cetuximab and trastuzumab to canine mammary carcinoma cells CF33, CF41, Sh1b and P114 was confirmed by flow cytometry. Both antibodies significantly inhibited canine tumor cell proliferation partly due to growth arrest in G(0)/G(1) phase. We explain the lower efficiency on the tested canine than on human SKBR3 and A431 cells, by a 2-log lower expression level of the canine ErbB-1 and -2 molecules. Our results indicate significant homology of human and canine Erb-1 and -2 tumor associated antigens. The fact that the canine homologues express the cetuximab and trastuzumab epitopes may facilitate antibody-based immunotherapy in dogs. Importantly, the striking similarities of ErbB-1 and -2 molecules open up avenues towards comparative strategies for targeted drug development.     

CD44+/CD24-细胞在乳腺癌组织及细胞系中的数量与分布

目的 检测CD44+/CIY24-细胞在乳腺癌组织及细胞系中的分布及数量,探讨其与乳腺癌常用标志物表达和乳腺癌分子亚型的关系.方法 采用免疫组织化学SP双染及单染法,分别检测了60例乳腺浸润性导管癌中的CD44及C1724的共表达情况和ER、PR、HER2、人雌激素诱导蛋白PS2、bcl-2、nm23的单独表达情况,同时检测了三种乳腺痛细胞系(MCF-7、MDA-MB-468及MDA-MB-231)中CD44及CD24的表达情况.结果 不同病例标本中CD44+/C1724-细胞的数量差异较大,分布无明显规律,总阳性率为65.0%;CD44+/CD24-细胞数量与患者年龄、肿瘤大小、淋巴结转移情况及ER、PR、HER-2、人雌激素诱导蛋白PS2、bcl-2、nm23表达情况无关(P均>0.05);CD44+/CD24-细胞数量与乳腺癌分子亚型无关.CD44+/CIY24-细胞在MCF-7、MDA-MB-468及MDA-MB-231细胞系中的比例分别为<1%、5%及>80%.结论 CD44+/CD24-细胞存在于部分乳腺癌组织及细胞系中,其数量及分布与乳腺癌的分子亚型和临床病理参数无直接关系.     

CD44+CD24-/low乳腺癌干细胞活性与多药耐药的相关性

BACKGROUND:Tumor stem cells are found to be involved in the recurrence, metastasis and drug resistance of the tumor. OBJECTIVE:To explore the relationship between cell activity and multidrug resistance of CD44⁺CD24^-/low breast cancer stem cells. METHODS: CD44⁺CD24^-/low breast cancer stem cells sorted from multidrug resistant breast cancer cell line MCF-7/ADR were detected as percentage using flow cytometry. P-gp fluorescence intensity of the cell membrane and MDR mRNA expression in sorted cells and MCF-7/ADR were detected using flow cytometry and RT-PCR, respectively. RESULTS AND CONCLUSION:After sorting by flow cytometry, the proportion of CD44⁺CD24^-/low breast cancer stem cells was more than 90%, indicating that the sorted cells could meet the needs of the subsequent experiment. CD44⁺CD24^-/low cell subsets exhibited stronger ability to form microspheres than non- CD44⁺CD24^-/low cell subsets. The P-gp fluorescence intensity and MDR mRNA expression of CD44⁺CD24^-/low cells were significantly higher than those of MFC-7/ADR cell line (P < 0.05). These experimental findings suggest that CD44⁺CD24^-/low breast cancer stem cells sorted from MCF-7/ADR cell lines have a strong ability to form cell microspheres in vitro, and significantly raise the level of P-gp protein and MDR mRNA expression, which may be one of the causes of multidrug resistance.     

Skewed differentiation of bone marrow CD34+ cells of tumor bearers from dendritic toward monocytic cells,and the redirection of differentiation toward dendritic cells by 1alpha,25-dihydroxyvitamin D3

Tumor presence is detrimental to the development of antigen-presenting dendritic cells. Since dendritic cells can arise from CD34+ precursor cells, the present study assessed the capacity of bone marrow CD34+ cells from tumor bearers to develop into dendritic cells when cultured in the absence of either tumor cells or their products. Culturing bone marrow CD34+ cells from mice bearing Lewis lung carcinomas yielded a lower number of dendritic cells than arose from CD34+ cells of normal mice. This reduced yield of dendritic cells was associated with a shift to development of monocytic cells and a reduced antigen presenting capability by the cultures. When the CD34+ cell cultures from tumor bearers were supplemented with the differentiation-inducing hormone 1alpha,25-dihydroxyvitamin D3, there was the restoration of dendritic cell development and antigen presenting ability. These results show that CD34+ cells from tumor bearers remain defective in their development into dendritic cells even when cultured outside the tumor environment, but development of dendritic cells can be restored with 1alpha,25-dihydroxyvitamin D3.