Expression of Ly-6D on the Surface of Normal and Neoplastic Mammary Epithelial Cells of the Mouse

Rat were immunized with mouse mammary epithelial cells and monoclonal antibodies (MAbs) were obtained to identify antigens stably expressed on the surface of both normal and neoplastic mammary epithelial cells of the mouse. Examination of the reactivities of the MAbs by immunofluorescence staining of tissue sections showed that one of the antibodies, MAb 2A2, reacted with luminal epithelium of the mammary gland and spontaneous mammary carcinomas of SHN mice. Further examination of the tissue lysates by western blot analysis revealed that MAb 2A2 reacts with a 17-kDa antigen expressed in normal mammary epithelial cells and mammary carcinoma cells. The antigen recognized by MAb 2A2 was absent in the lysates of liver, lung, salivary gland, kidney, small intestine, ovary and uterus. After immunoaffinity purification of the MAb 2A2- recognized antigen and determination of its N-terminal amino acid sequence, we identified the antigen as Ly-6D, also known as ThB, which belongs to a family of glycosyl-phosphatidylinositol-anchored cell surface proteins. Northern blot analysis further demonstrated that Ly-6D mRNA is expressed in the mammary gland. Based on these observations we concluded that Ly-6D is stably expressed on the surface of both normal and neoplastic mammary epithelial cells of the mouse. Ly-6D will serve as a useful epithelial cell surface marker for the study of mammary gland development, as well as for breast cancer research.     

MCPH1 Protein Expression in Normal and Neoplastic Lung Tissues

Lung cancer is the most common cause of cancer-related death in the world. The main types are small-cell lungcarcinoma (SCLC) and non-small-cell lung carcinoma (NSCLC), the latter including squamous cell carcinoma(SCC), adenocarcinoma and large cell carcinoma. NSCLCs account for about 80% of all lung cancer cases.Microcephalin (MCPH1), also called BRIT1 (BRCT-repeat inhibitor of hTERT expression), plays an importantrole in the maintenance of genomic stability. Recently, several studies have provided evidence that the expressionof MCPH1 gene is decreased in several different types of human cancers. We evaluated the expression of proteinMCPH1 in 188 lung cancer and 20 normal lung tissues by immunohistochemistry. Positive MCPH1 stainingwas found in all normal lung samples and only some cancerous tissues. MCPH1-positive cells were significantlylower in lung carcinoma compared with normal tissues. Furthermore, we firstly found that MCPH1 expressionin lung adenocarcinoma is higher than its expression in squamous cell carcinoma. Change in MCPH1 proteinexpression may be associated with lung tumorigenesis and may be a useful biomarker for identification ofpathological types of lung cancer.     

Estrogen and Progesterone in Normal Mammary Gland Development and in Cancer

There is emerging evidence that the mammary epithelium in both mice and humans is arranged as a hierarchy that spans from stem cells to differentiated hormone-sensing, milk-producing and myoepithelial cells. It is well established that estrogen is an important mediator of mammary gland morphogenesis and exposure to this hormone is associated with increased breast cancer risk. Yet surprisingly, the primitive cells of the mammary epithelium do not express the estrogen receptor-α (ERα) or the progesterone receptor. This article will review the mammary epithelial cell hierarchy, possible cells of origin of different types of breast tumors, and the potential mechanisms on how estrogen and progesterone may influence the different subcomponents in normal development and in cancer. Also presented are some hypothetical scenarios on how this underlying biology may be reflected in the behavior of ERα(+) and ERα(-) breast tumors.     

Hydralazine-induced Changes in Tissue Perfusion and Radiation Response in A C3H Mammary Carcinoma and Mouse Normal Tissues

Hydralazine has been reported to reduce blood perfusion in tumours, thereby increasing hypoxia and subsequently enhancing tumour sensitivity to certain drugs and hyperthermia. We have investigated the ability of hydralazine to induce such changes in a C3H mouse mammary carcinoma and various normal tissues. in tumours, hydralazine (5mg/kg; i.v.) modified the radiation response, measured by a local tumour control assay, producing an effect equivalent to that seen in tumours made fully hypoxic by clamping. This effect was time-dependent and correlated with the decrease in tissue perfusion estimated by the 86-RbCl extraction procedure. Similar effects were seen in normal skin, although the changes were less dramatic and of a shorter duration. Hydralazine also reduced 86-RbCl uptake in liver, kidney, gut and spleen, but not in bladder, muscle and lung, suggesting that it may have the potential to increase the sensitivity of some normal tissues to hypoxic cell cytotoxins.     

Expression Profile and Potential Roles of EVA1A in Normal and Neoplastic Pancreatic Tissues

Background: EVA1A (eva-1 homolog A) is a novel gene that regulates programmed cell death throughautophagy and apoptosis. Our objective was to investigate the expression profiles and potential role of EVA1Ain normal and neoplastic human pancreatic tissues. Materials and Methods: The expression pattern of EVA1Ain normal pancreatic tissue was examined by indirect immunofluorescence and confocal microscopy. Proteinlevels in paraffin-embedded specimens from normal and diseased pancreatic and matched non-tumor tissueswere evaluated by immunohistochemistry. Results: EVA1A colocalized with glucagon but not with insulin,demonstrating production in islet alpha cells. Itwas strongly expressed in chronic pancreatitis, moderately orweakly expressed in the plasma membrane and cytoplasm in pancreatic acinar cell carcinoma, and absent innormal pancreatic acinar cells. Although the tissue architecture was deformed, EVA1A was absent in the alphacells of pancreatic ductal adenocarcinomas, intraductal papillary mucinous neoplasms, mucinous cystadenomas,solid papillary tumors and pancreatic neuroendocrine tumors. Conclusions: EVA1A protein is specificallyexpressed in islet alpha cells, suggesting it may play an important role in regulating alpha-cell function. Theectopic expression of EVA1A in pancreatic neoplasms may contribute to their pathogenesis and warrants furtherinvestigation.     

Amphiregulin Mediates Estrogen, Progesterone, and EGFR Signaling in the Normal Rat Mammary Gland and in Hormone-Dependent Rat Mammary Cancers

Both estrogen (E) and progesterone (P) are implicated in the etiology of human breast cancer. Defining their mechanisms of action, particularly in vivo, is relevant to the prevention and therapy of breast cancer. We investigated the molecular and cellular mechanisms of E and/or P-induced in vivo proliferation, in the normal rat mammary gland and in hormone-dependent rat mammary cancers which share many characteristics with the normal human breast and hormone-dependent breast cancers. We show that E+P treatment induced significantly greater proliferation in both the normal gland and mammary cancers compared to E alone. In both the normal gland and tumors, E+P-induced proliferation was mediated through the increased production of amphiregulin (Areg), an epidermal growth factor receptor (EGFR) ligand, and the activation of intracellular signaling pathways (Erk, Akt, JNK) downstream of EGFR that regulate proliferation. In vitro experiments using rat primary mammary organoids or T47D breast cancer cells confirmed that Areg and the synthetic progestin, R5020, synergize to promote cell proliferation through EGFR signaling. Iressa, an EGFR inhibitor, effectively blocked this proliferation. These results indicate that mediators of cross talk between E, P, and EGFR pathways may be considered as relevant molecular targets for the therapy of hormone-dependent breast cancers, especially in premenopausal women.     

Histological Findings of Mammary Gland Development and Risk of Breast Cancer in BRCA1 Mutant Mouse Models

PurposeThe breast cancer susceptibility gene, BRCA1, is involved in normal development and carcinogenesis of mammary glands. Here, we aimed to evaluate the relationship between histological findings of mammary gland development and breast cancer risk in BRCA1 mutant mice.MethodsFive BRCA1 mutant mice and five non-mutant FVB/NJ mice were used for each group of 1-month-old (pubertal), 3-month-old (fertile), and 8-month-old (menopausal) mice. In another experiment, 15 BRCA1 mutant mice were followed up to 8 months after birth and classified into tumor-bearing (11 mice) and tumor-free (4 mice) groups. Excised mammary gland tissues were stained with Carmine Alum, and the number of terminal end buds (or alveolar buds), branching density, and duct elongation were measured using image analysis programs. Differences between the two groups were assessed using paired t-test.ResultsOne-month-old BRCA1 mutant mice showed a higher number of terminal end buds (23.8 ± 1.0 vs. 15.6 ± 0.8, p = 0.0002), branching density (11.7 ± 0.4 vs. 9.6 ± 0.5%, p = 0.0082), and duct elongation (9.7 ± 0.7 vs. 7.3 ± 0.4 mm, p = 0.0186) than controls. However, there was no difference between the 3- and 8-month-old groups. In BRCA1 mutant mice, the tumor-bearing group showed a significantly higher number of alveolar buds (142.7 ± 5.5 vs. 105.5 ± 5.4, p = 0.0008) and branching density (30.0 ± 1.0 vs. 24.1 ± 1.1%, p = 0.008) than the tumor-free group; however, duct elongation was not different (23.9 ± 0.6 vs. 23.6 ± 0.6 mm, p = 0.8099) between the groups.ConclusionBRCA1 mutant mice exhibited early pubertal mammary gland development and delayed age-related mammary gland involution was associated with breast cancer. Our results may have clinical implications for predicting breast cancer risk and developing prevention strategies for BRCA1 mutation carriers.     

Establishment of Two Hormone-responsive Mouse Mammary Carcinoma Cell Lines Derived from a Metastatic Mammary Tumor

We report the establishment of two mouse mammary cancer cell lines, MC7-2A and MC7-2B obtained from a mouse mammary carcinoma induced by medroxyprogesterone acetate (MPA) and maintained by syngeneic transplantation in BALB/c mice. They are epithelial (express cytokeratins) and express both estrogen receptors alpha (ERalpha) and progesterone receptors (PRs) isoforms A and B (western blots). In vitro, MPA inhibited 3H-thymidine uptake, starting from concentrations as low as 10(-13) M in MC7-2A and 10(10) M in MC7-2B; the antiprogestin RU 486 exerted a stimulatory effect at 10(-14) M in both cell lines; 17-beta-estradiol (E2) also exerted a stimulatory effect starting at 10(-10) M in MC7-2A and at 10(-13) M in MC7-2B. When transplanted in syngeneic mice, both cell lines originated adenocarcinomas that gave rise to lung metastases within 3 months. In in vivo studies, in MC7-2A, the antiprogestin inhibited completely tumor growth, E2 induced a slight although significant ( p < 0.05) stimulatory effect and MPA stimulated tumor growth while MC7-2B cells were unresponsive to all treatments. ER and PR were also expressed in tumors as assessed by immunohistochemistry. Two marker chromosomes were identified by FISH as translocations between chromosomes 4 and 7, and between chromosomes X and 2; the third marker chromosome remains unidentified. All these markers were also present in the parental tumor. A new marker, a centric fusion of chromosomes 2, was acquired in both cell lines. Considering that there are very few murine breast carcinoma responsive cell lines, these cells represent new tools in which the regulatory effect of hormones can be studied.     

乳腺局限性腺体增厚与早期乳腺癌

目的探讨乳腺局限性腺体增厚与癌前病变和早期乳腺癌的关系.方法自1992年1月至2001年6月共对148例乳腺局限性腺体增厚者施行切检,并对其病理结果进行分析.结果148例乳腺局限性腺体增厚患者中乳头状瘤病和/或导管上皮增生活跃(癌前病变)17例,占11.5%,T0期乳腺癌14例,占9.46%.随访1日至9年,除1例乳腺癌患者(保乳手术加放疗)于术后1年半复发伴全身广泛转移而死亡外,余均无复发、转移发生.结论乳腺局限性腺体增厚既是癌前病变,又是早期乳腺癌的重要体征之一,对不随月经周期改变的乳腺局限性腺体增厚观察半年以上不见好转者均应切检,绝经后患者宜尽早切检.肿瘤防治杂志,2001,8(特)269-271     

Mammary leukaemia (ML) antigen isolated from L 1210 leukaemia cells.

Crude 3 M KCl extracts from L 1210 cells and purified ML antigen were characterized and the presence of ML antigens was verified by various anti-ML sera, as well as by antisera to disrupted MMTV B particles. Selected ML-positive fractions from preparative polyacrylamide electrophoresis and purified ML antigen isolated by affinity chromatography were analyzed by polyacrylamide disc electrophoresis. With both procedures the same sharp band was obtained. The molecular weight of both preparations was found to be 73,500 as estimated. The relationship between ML antigen, MMTV antigenic products and cell-associated viral proteins is discussed.