The immunopathology of gross cystic disease fluid proteins

The Lipocalin Apolipoprotein D Functional Portrait: A Systematic Review

Apolipoprotein D is a chordate gene early originated in the Lipocalin protein family. Among other features, regulation of its expression in a wide variety of disease conditions in humans, as apparently unrelated as neurodegeneration or breast cancer, have called for attention on this gene. Also, its presence in different tissues, from blood to brain, and different subcellular locations, from HDL lipoparticles to the interior of lysosomes or the surface of extracellular vesicles, poses an interesting challenge in deciphering its physiological function: Is ApoD a moonlighting protein, serving different roles in different cellular compartments, tissues, or organisms? Or does it have a unique biochemical mechanism of action that accounts for such apparently diverse roles in different physiological situations? To answer these questions, we have performed a systematic review of all primary publications where ApoD properties have been investigated in chordates. We conclude that ApoD ligand binding in the Lipocalin pocket, combined with an antioxidant activity performed at the rim of the pocket are properties sufficient to explain ApoD association with different lipid-based structures, where its physiological function is better described as lipid-management than by long-range lipid-transport. Controlling the redox state of these lipid structures in particular subcellular locations or extracellular structures, ApoD is able to modulate an enormous array of apparently diverse processes in the organism, both in health and disease. The new picture emerging from these data should help to put the physiological role of ApoD in new contexts and to inspire well-focused future research.

Apocrine lesions of the breast

Apocrine change is recognised in benign, atypical and malignant lesions of the breast. Apocrine metaplasia, a frequent finding in the breast of women over the age of 25 years, is most commonly seen in benign cysts with a simple or papillary configuration. Apocrine change is also recognised in other benign lesions including sclerosing adenosis, now known as apocrine adenosis. Apocrine atypia usually refers to cytological atypia in which there is at least threefold variation in nuclear size but architectural atypia may also occur. The distinction between atypical apocrine hyperplasia and non-high-grade apocrine ductal carcinoma in situ may be difficult due to the relative rarity of these entities and the lack of validated diagnostic criteria. Lobular carcinoma in situ (LCIS) with apocrine change is considered to be a variant of pleomorphic LCIS. An apocrine variant of encapsulated papillary carcinoma is also recognised. Apocrine change is described in invasive carcinoma, including no special type, lobular, micropapillary and mucinous variants. The recent WHO 2019 update recognises 'carcinoma with apocrine differentiation' as a special type breast carcinoma based on the presence of apocrine morphology in at least 90% of the tumour. Tumours with apocrine morphology are usually but not always hormone receptor negative. Human epidermal growth factor receptor 2 (HER-2) status is variable. Molecular studies have identified breast tumours with apocrine features and high expression of androgen receptor mRNA including 'luminal androgen receptor tumours' and 'molecular apocrine tumours'. The term 'pure apocrine carcinoma' has been proposed to describe an invasive carcinoma with apocrine morphology that is oestrogen and progesterone receptor negative and androgen receptor positive. HER-2 status may be positive or negative. This article reviews the pathology of benign, atypical and malignant apocrine lesions of the breast, with emphasis on diagnostic criteria including an approach to evaluation of apocrine lesions on needle core biopsy, and recent advances in our understanding of invasive apocrine carcinoma.

Prognostic Factors for Carcinoma of the Male Breast

Male mammary carcinoma (MMC) affects approximately 1000 men in the United States each year. Aside from the impact of estrogen-receptor positivity on the clinical course of this tumor, relatively little information exists in published form on the ability of special pathologic studies to predict its biologic behavior. The authors analyzed 26 cases of invasive ductal MMC, comparing overall survival with tumor size, histologic grade (Page and Anderson), immunohistologic estrogen receptor protein status, DNA ploidy, expression of S 100 and gross cystic disease fluid proteins, and immunohisto chemically-detected amplification of the c-erbB-2 (HER-2/neu) oncoprotein. Tumor size and amplification of c-erbB-2 oncoprotein emerged as the statistically significant predictors in this group; MMCs of <2 cm had a more favorable prognosis than large tumors. Estrogen receptor protein was seen in 80% of cases; c-erbB-2 amplification was present in 35%; 80% were DNA-aneuploid; and S 100 and gross cystic disease fluid were observed in 38% and 62% of cases, respectively. The latter data are virtually identical to those on histologically similar tumors in women, but all except c-erbB-2 failed to achieve statistical prognostic value in this study. Substrata of histologic grades among MMCs were numerically too small to subject to statistical assessment. These findings suggest that no substantive differences exist between the pathologic features of male and female breast cancers. They also indicate that adjunctive laboratory studies are currently unhelpful in the prognostication of MMC. Int J Surg Pathol 2(3):199-206, 1995

Gross cystic disease fluid protein-(GCDFP-15): expression in primary lung adenocarcinoma

A total of 211 cases of primary lung adenocarcinoma were tested for expression of gross cystic disease fluid protein-15 (GCDFP-15) and only 11 cases (5.2%) were positive. The cases occurred with an equal sex distribution in older individuals whose carcinomas were frequently identified on screening radiographs. The adenocarcinomas were peripheral lesions and had an average size of 2.9 cm (range, 1.1 to 7.0). Histologically, they were usually mixed acinar and papillary adenocarcinomas with abundant extracellular mucin production, with the neoplastic cells having a polygonal shape, round to oval nuclei, diffuse powdery chromatin, and abundant eosinophilic granular cytoplasm. Clear cells and apocrinelike cells with prominent central nucleoli were common. GCDFP-15 was expressed in conjunction with thyroid transcription factor-1 in 81% of cases and synaptophysin was seen in 65%. Estrogen and progesterone receptors were not expressed. EGFR gene amplification and mutations of exons 19 and 21 were rare. KRAS mutations and HER2 gene amplification were not seen. This report details the first 11 cases of pulmonary adenocarcinoma to express GCDFP-15 and their distinctive morphology with frequent mucin production and coexpression of thyroid transcription factor-1 and synaptophysin.

Non-operative breast pathology: apocrine lesions

Apocrine metaplasia is a very common finding in the female breast after the age of 25. It is so common that many people regard it as a normal component of the breast. This, however, is only really the case in apocrine sweat glands of the axilla and in the peri-areolar apocrine glands. The apocrine cell does, however, contribute to a number of different breast lesions, some of which are very taxing diagnostically; apocrine variants of both in-situ and invasive cancer are encountered. This review considers the common apocrine metaplastic lesions seen in fibrocystic change as well as apocrine adenoma, apocrine change within sclerosing adenosis, atypical apocrine lesions and apocrine malignancies.

Proteomic approach for purification of seminal plasma proteins involved in tumor proliferation

Human seminal plasma contains a large array of proteins required for the normal physiology and metabolism of spermatozoa. These are mainly secreted from prostate epithelium, testes, and seminal vesicles. Fortunately, many of these are found to be present at elevated concentration in seminal plasma and act as a biomarker of different carcinomas as their levels are also enhanced in serum and are found to be involved in tumor progression and metastasis apart from fertility. The proteins which were overexpressed in the seminal plasma of prostate carcinoma patients were identified by 2-DE and MALDI-TOF/MS. We have designed a strategy to purify these four proteins prostate specific antigen (PSA), prostatic acid phosphatase (PAP), Zinc alpha2-glycoprotein (ZAG), and progastricsin (PG), together in homogeneity by using simple chromatographic techniques. Acidic and basic fractions of human seminal plasma were separated by ion exchange chromatography and further purified by gel permeation chromatography. Our results form a new and valuable resource for those attempting structure-based drug designing for prostate and other cancers where the amount of proteins is required in plenty and in native form.

Expression of androgen receptor and two androgen-induced proteins (apolipoprotein D and pepsinogen C) in ductal carcinoma in situ of the breast

AIMS

To evaluate the expression of androgen receptors (AR) and two androgen-induced proteins [apolipoprotein D (ApoD) and pepsinogen C (PepC)] in ductal carcinoma in situ (DCIS) of the breast.

METHODS AND RESULTS

AR, ApoD and PepC expression was examined in 28 cases of pure DCIS and in 31 cases of DCIS adjacent to invasive carcinoma of the breast using immunohistochemical methods and then correlated with the architectural subtype, the degree of differentiation and the ostrogen receptor (ER)/progesterone receptor (PgR)/HER-2 status. We found no significant differences between pure DCIS and DCIS adjacent to invasive breast cancer regarding the percentage of positive cases for ApoD (64.3% versus 54.8%), PepC (42.9% versus 48.4%), ER (64.3% versus 58.1%), PgR (60.7% versus 58.1%) and HER-2 (39.3% versus 67.7%). However, there was a significantly higher percentage of AR+ DCIS among those adjacent to invasive carcinomas of the breast than among pure DCIS lesions (93.5% versus 60.9%) (P = 0.009). AR expression did not correlate with architectural subtype, degree of differentiation, or ER/PgR/HER-2/ApoD/PepC status, in cases of pure DCIS, nor in DCIS adjacent to invasive carcinoma of the breast.

CONCLUSIONS

AR expression may represent an independent predictive factor in DCIS of the breast.

Immunohistochemical localization of gross cystic disease fluid protein-15, -24 and -44 in ductal carcinoma in situ of the breast: relationship to the degree of differentiation

AIMS

Three major proteins present in breast gross cystic disease fluid and expressed by the cyst lining apocrine epithelium are gross cystic disease fluid protein-15 (GCDFP-15), apolipoprotein-D (APO-D; GCDFP-24) and zinc alpha2-glycoprotein (ZnGP; GCDFP-44). The aim of this study was to investigate the expression of these proteins in ductal carcinoma in situ (DCIS) of the breast and to relate their expression with the degree of differentiation of DCIS.

METHODS AND RESULTS

An immunohistochemical study of these proteins was performed in 57 cases of DCIS and nine cases of morphologically apocrine DCIS. Positivity was seen in 24/57 (42.1%) cases with anti-GCDFP-15, 20/57 (35.1%) cases with anti-GCDFP-24 and 22/57 (38.6%) cases with anti-GCDFP-44. GCDFP-15 positivity was noted in 5/13 (38.5%) of the well-differentiated, 11/19 (57.9%) intermediately differentiated and 8/25 (32.0%) of the poorly differentiated cases (P=0.217). GCDFP-24 positivity was seen in 3/13 (23.0%) well-differentiated, 9/19 (47.4%) intermediately differentiated and 8/25 (32.0%) poorly differentiated cases (P=0.336). GCDFP-44 was detected in 5/13 (38.5%) of well-differentiated cases, 11/19 (57.9%) intermediately differentiated and 6/25 (24.0%) poorly differentiated cases (P=0.074). In the nine cases of apocrine DCIS, GCDFP-15 positivity was detected in seven (77.8%), while five (55.6%) and six (66.7%) cases were positive for GCDFP-24 and GCDFP-44, respectively.

CONCLUSIONS

The results indicate that there is no significant association between the expression of the studied proteins and the degree of differentiation of DCIS of the breast. Moreover, some morphologically apocrine DCIS cases appear to lose expression of these proteins.

Expression and clinical significance of apolipoprotein D in epithelial ovarian carcinomas

OBJECTIVE

Apolipoprotein D is a protein component of the human plasma lipid transport system but is also associated with a more favorable prognosis in women with breast cancer. This retrospective study was undertaken to examine the tumoral expression of apolipoprotein D in epithelial ovarian cancer and to analyze the possible correlation with tumor and patient characteristics as well as androgen receptors and their prognostic significance.

METHODS

Immunohistochemical evaluation was used to examine apolipoprotein D expression in paraffin blocks from 68 epithelial ovarian carcinomas.

RESULTS

A total of 18 (26.4%) tumors stained positively. No significant correlation was found between apolipoprotein D expression and patient or tumor characteristics and androgen receptor status. However, apolipoprotein D expression was significantly associated with prognosis in patients with residual tumor greater than 1 cm. Thus, patients with apolipoprotein-D-negative tumors had a poorer overall survival than those with apolipoprotein-D-positive tumors (P = 0.039). In addition, multivariate analysis demonstrated that apolipoprotein D expression was an independent prognostic factor with initial tumor size in this group of patients (P = 0.005).

CONCLUSIONS

Our results led us to consider the existence of apolipoprotein D expression by a significative percentage of ovarian carcinomas, and this protein expression might be of clinical usefulness for identifying lesions with different evolution.

Immunohistochemical analysis of GCDFP-15 and GCDFP-24 in mammary and non-mammary tissue

BACKGROUND

Gross cystic disease fluid protein (GCDFP)-15, a major constituent protein in breast cysts, is known to be a marker of breast cancer, while the diagnostic value of GCDFP-24, a protein with a molecular weight of 24,000 daltons, has not been determined. The aim of this study was to elucidate the usefulness of GCDFP-24 for the differential diagnosis of breast cancer in combination with GCDFP-15 and to characterize the histologic features of GCDFP-24-positive breast cancer.

METHODS

A total of 326 samples including non-neoplastic tissue and benign and malignant tumors from several anatomic sites were examined using commercially available monoclonal antibodies against GCDFP-15 and GCDFP-24.

RESULTS

In non-mammary tissue, GCDFP-15 was detected in skin, salivary gland, bronchial gland, prostate and seminal vesicle, and GCDFP-24 was detected in apocrine glands and peripheral nerve. Thirty-seven (44.6%) and 22 (26.5%) samples of 83 breast cancers were positive for GCDFP-15 and -24, respectively. Combined assays of GCDFP-15 and -24 raised the positive rate to 50.6%. The markers were not detected in tumors originating from gastrointestinal tract, bronchopulmonary structures or the genitourinary system. Breast cancers positive for both GCDFP-15 and GCDFP-24 were of lower histologic grade according to Bloom & Richardson's scoring system (p < 0.05).

CONCLUSION

Immunohistochemical analysis of GCDFP-24 in combination with GCDFP-15 expression was useful for definitive diagnosis of breast cancers, and the expression of these markers correlated with low grade breast cancer.

Expression and clinical significance of apolipoprotein D in male breast cancer and gynaecomastia

BACKGROUND

Apolipoprotein D (Apo D) is a protein component of the human plasma lipid transport system which is present in benign and malignant human breast tissues. This study analysed the expression of Apo D in men with gynaecomastia or breast cancer, and evaluated its use as a prognostic marker in breast cancer.

METHODS

Immunohistochemical expression of Apo D was examined in specimens from 15 men with gynaecomastia, two with in situ breast carcinoma and 68 with invasive male breast cancer. Median follow-up in patients with breast cancer was 44 months.

RESULTS

All gynaecomastia specimens, both in situ carcinomas and 57 invasive carcinomas (84 per cent) stained positively for Apo D. Apo D values were significantly correlated with axillary node involvement and histological grade of the tumours. In men with breast cancer univariate analysis showed a statistical association between node status and Apo D content with relapse-free survival (P < 0.001) and overall survival (P < 0.05). Cox multivariate analysis showed that Apo D was a significant indicator of relapse-free survival (P = 0. 0089), but node status was the strongest factor able to predict both relapse-free (P = 0.0336) and overall (P = 0.0346) survival.

CONCLUSION

Apo D was expressed in gynaecomastia and a high percentage of male breast carcinomas. There was a positive association of Apo D content in male breast tumours with favourable outcome. Apo D expression was a significant independent indicator of relapse-free survival in male breast cancer.

Immunolocalization of apolipoprotein D, androgen receptor and prostate specific antigen in early stage prostate cancers

PURPOSE

To determine the cellular distribution and levels of immunohistochemical staining for apolipoprotein D (Apo-D), prostate specific antigen (PSA) and androgen receptor (AR) in early stage prostate cancers.

MATERIALS AND METHODS

Cellular distribution of Apo-D, PSA and AR in 30 stage A/B prostate cancers and in non-malignant glandular tissue contained in the same sections was detected immunohistochemically, and staining was evaluated by computerized video image analysis.

RESULTS

Staining for Apo-D (percentage positive cellular area) was significantly increased in tumor cells of early stage prostate cancers compared with non-malignant glandular tissue. PSA and AR were present at high levels in both early stage prostate tumors and non-malignant prostate.

CONCLUSIONS

Malignant transformation in the prostate is associated with increased cellular levels of Apo-D.

Retinoic acid-induced expression of apolipoprotein D and concomitant growth arrest in human breast cancer cells are mediated through a retinoic acid receptor RARalpha-dependent signaling pathway

Apolipoprotein D (apoD) is a human plasma protein, belonging to the lipocalin superfamily, that is produced by a specific subtype of highly differentiated breast carcinomas and that is strongly up-regulated by retinoic acid (RA) in breast cancer cells. In this work, we have examined the molecular mechanisms mediating the induction of apoD gene expression by retinoids in T-47D human breast cancer cells. Northern blot analysis revealed that Ro40-6055, a synthetic retinoid that selectively binds and activates the retinoic acid receptor RARalpha, induced the accumulation of apoD mRNA in breast cancer cells in a time- and dose-dependent manner. The time course analysis demonstrated that apoD mRNA was induced 14-fold over control cells after 48 h of incubation with 10(-8) M Ro40-6055. As little as 10(-11) M of this retinoid induced apoD mRNA 5-fold over the control, whereas incubation with 10(-7) M Ro40-6055 induced maximally 15-fold over control cells. RARalpha-selective antagonists counteracted the inductive effects of all-trans-RA, 9-cis-RA, and Ro40-6055 on the expression of apoD, when present at the same concentration as the retinoid agonists. By contrast, RARbeta-, RARgamma-, and RXR-selective retinoids did not affect apoD gene expression. The retinoid agonist Ro40-6055 had an antiproliferative effect on T-47D cells, with maximal growth inhibition of approximately 60% obtained after 7 days of incubation with 10(-7) M. This antiproliferative effect could be counteracted by a 100-fold excess of the antagonist Ro41-5253. Treatment of the cells with retinoids that do not bind the nuclear retinoic acid receptors did not affect apoD expression, despite the fact that they did have a strong antiproliferative effect on T-47D cells. On the basis of these results, a role for RARalpha on apoD gene expression induction by retinoids in breast cancer cells is proposed.

Expression of the androgen receptor and an androgen-responsive protein, apolipoprotein D, in human breast cancer

Little is known regarding the activity and function of the androgen receptor (AR) in human breast cancer. In the present study AR was evaluated in untreated primary breast cancers using antisera to the amino- and carboxy-termini of the receptor and quantitated using colour video image analysis. A strong correlation between tissue concentration and percentage AR-positive cells was observed for each antiserum. However, comparison of percentage positive cells using the amino- and carboxy-terminal AR antisera in individual breast cancer specimens revealed a subset of tumours with discordantly increased staining for the carboxy terminus. These findings suggest the presence of amino-terminal-truncated AR in a proportion of breast cancer cells or presence of AR mutations or associated protein alterations that affect binding of the amino-terminal AR antiserum. Immunohistochemical expression of the androgen-regulated glycoprotein, apolipoprotein D (apo-D), was also evaluated in the breast cancer specimens. Focal positivity of apo-D staining, which did not always co-localise with AR-positive cells, was observed within breast tumours. Furthermore, no correlation was evident between percentage positive cells stained for AR and apo-D in breast cancer specimens. These findings indicate that, although apo-D expression is androgen regulated in human breast cancer cell lines in vitro, its expression in primary breast cancers may be regulated by other factors. The expression of AR in primary breast cancers also suggests that the receptor may be involved in tumour responsiveness or in abnormal responses to endocrine therapies.

Hormonal regulation of the human pepsinogen C gene in breast cancer cells. Identification of a cis-acting element mediating its induction by androgens, glucocorticoids, and progesterone

Pepsinogen C is an aspartic proteinase mainly involved in the digestion of proteins in the stomach, which is also synthesized by certain human breast tumors. To examine the possibility that extragastric production of this proteolytic enzyme could be mediated by hormonal factors, we have analyzed pepsinogen C gene expression in human breast cancer cells subjected to different hormonal treatments. Northern blot analyses revealed the expression of pepsinogen C gene by T-47D breast cancer cells after induction with dihydrotestosterone, dexamethasone, and progesterone but not with estradiol, retinoic acid, or ethanol. Reverse transcription-polymerase chain reaction analysis in a series of breast cancer cell lines confirmed the amplification of pepsinogen C mRNA after induction with dihydrotestosterone, in those cells expressing the androgen receptor mRNA. The promoter region of the pepsinogen C gene was functionally characterized by transient expression of a vector containing the promoter region cloned in front of the chloramphenicol acetyltransferase (CAT) reporter gene. CAT activity in T-47D cells was stimulated in the presence of dihydrotestosterone, dexamethasone, and progesterone but not by estradiol. By further deletion mapping of the pepsinogen C promoter, a minimal region (AGAACTattTGTTCC) was identified as being responsible for glucocorticoid-, androgen-, and progesterone-regulated gene expression.

Differential expression of apolipoprotein-D and prostate specific antigen in benign and malignant prostate tissues

PURPOSE

To investigate Apolipoprotein-D (Apo-D) and prostate specific antigen (PSA) immunohistochemical staining of nonmalignant and malignant human prostate tissues.

MATERIALS AND METHODS

Apolipoprotein-D and PSA immunoreactivity were evaluated by video image analysis in nonmalignant prostates and in 30 stage D2 prostate cancers.

RESULTS

Apolipoprotein-D was detected in all 30 tumors, and the level of staining was elevated in comparison to age-matched nonmalignant prostates (p < 0.05). In contrast, the level of PSA staining in tumors was less than that detected in nonmalignant prostates.

CONCLUSIONS

Apolipoprotein-D is expressed in normal human prostate. Elevated Apo-D staining is associated with advanced prostate cancer.

Serum lipids and apolipoproteins in women with breast masses

BACKGROUND

Human mammary tissue metabolizes lipids from plasma, a process affected by female gonadal hormones. Both benign and malignant proliferation of breast tissue in women have been associated with changes in plasma lipid and lipoprotein levels.

METHODS

One hundred consecutive women with breast masses (50 malignant, 50 benign) had diagnostic biopsies followed by axillary node dissection in those with cancer. Fasting serum samples were taken just prior to biopsy and analyzed for lipid fatty acid and lipoprotein levels. Malignant breast tissue was analyzed for hormone receptor binding.

RESULTS

Low-density lipoprotein (LDL) components (total cholesterol, LDL-cholesterol, apolipoprotein B) were increased, but not significantly, in cancer patients compared to those with benign masses. Decreased levels of LDL-associated components were found in women with cancer recurrence by 3 years. Three apolipoproteins of high-density lipoprotein (apolipoprotein A-I, apolipoprotein A-II, apolipoprotein D) were more affected by the presence of breast masses than the lipids were. Fibrocystic disease, type of hormone binding, and recurrence within 3 years were significantly related to apolipoprotein changes, especially apolipoprotein D levels with hormone receptor binding and the apolipoprotein A-I/apolipoprotein B ratio with breast cancer recurrence.

CONCLUSIONS

Prior to diagnostic biopsy, serum lipid and apolipoprotein components of low-density lipoproteins were increased in women with fibrocystic disease and early stage cancer but decreased in women with early recurrence. However, apolipoprotein A-I, apolipoprotein A-II, and apolipoprotein D, of the high-density lipoproteins, were more affected than serum lipids. The ratio of apolipoprotein A-I to apolipoprotein B serum levels at time of biopsy was the best predictor of cancer recurrence.

Inverse relationships between cell proliferation and basal or androgen-stimulated apolipoprotein D secretion in LNCaP human prostate cancer cells

We have recently demonstrated that the biphasic action of androgens on LNCaP cell proliferation is opposite to their effect on apolipoprotein D (apo-D) secretion, the stimulation of apo-D secretion being associated with a steroid-induced inhibition of cell proliferation. To further characterize the control of apo-D expression in LNCaP cells, we studied basal as well as androgen-induced apo-D secretion in slowly proliferating, low-passage (LP; 20-29th) and rapidly proliferating high-passage (HP; 111-117th) cell cultures. For comparison, the androgen-induced stimulation of prostate specific antigen secretion was also investigated in LP and HP cell cultures. In the absence of androgens, basal cell proliferation of HP cells was significantly higher than that of LP cells, whereas apo-D secretion was higher in LP cells than in HP cells. Furthermore, the biphasic action of dihydrotestosterone and of the synthetic androgenic compound R1881 on apo-D release and cell proliferation was observed in both LP and HP cells. The stimulation of apo-D secretion was inversely related to that of cell proliferation and influenced by cell density. The inhibition of basal and androgen-induced cell proliferation by the calcium channel blocker nifedipine was also associated with an increase in apo-D secretion. The amount of PSA released and the sensitivity of its response to R1881 were increased in LP cells compared with HP cells. The present study thus demonstrates, for the first time, that apo-D secretion is inversely correlated to cell proliferation and cell density in the absence as well as in the presence of androgens in both LP and HP LNCaP human prostate cancer cells. This finding suggests that apo-D expression can be modulated not only by steroid hormones, but also by other factors involved in the control of cell proliferation.

Glucocorticoids and androgens up-regulate the Zn-alpha 2-glycoprotein messenger RNA in human breast cancer cells

We have studied the hormonal regulation of the gene encoding Zn-alpha 2-glycoprotein (Zn-alpha 2-gp), a human protein with a high degree of amino acid sequence similarity to class I histocompatibility antigens that is produced by a specific subset of breast carcinomas. Northern blot analysis revealed that dexamethasone and 5 alpha-dihydrotestosterone strongly induced the accumulation of Zn-alpha 2-gp mRNA in T-47D human breast cancer cells. Furthermore, the effect of these two hormones was shown to be additive, since the combination of both hormones produced a stimulation of Zn-alpha 2-gp mRNA of at least 3-fold over that produced by either hormone alone. By contrast, the addition of 5 beta-dihydrotestosterone, 17 beta-estradiol, or progesterone failed to induce the expression of Zn-alpha 2-gp. The stimulatory effect of glucocorticoids and androgens on Zn-alpha 2-gp expression was produced in a time and dose dependent manner, without significantly affecting the cell proliferation rate. A time-course study demonstrated that the induction of Zn-alpha 2-gp mRNA by androgens and glucocorticoids reached a level of 4 or 3.2-fold over the untreated control after seven days of incubation in the presence of a 10(-7) M concentration of 5 alpha-dihydrotestosterone or dexamethasone, respectively. A dose-response study showed that as little as 10(-11) M of 5 alpha-dihydrotestosterone or dexamethasone produced an accumulation of Zn-alpha 2-gp mRNA of 2.4 or 2.1-fold over the control, respectively. On the basis of these results, we propose that Zn-alpha2-gp may be useful as a biochemical marker of breast carcinomas with a specific pattern of hormone responsiveness in whose development glucocorticoids and/or androgens may play a significant role.

Secretion of breast gross cystic disease fluid proteins by T47D breast cancer cells in culture--modulation by steroid hormones

The effect of steroid hormones on modulating the secretion rates of three human breast gross cystic disease fluid proteins (GCDFP-15, GCDFP-24, and GCDFP-44) by T47D breast carcinoma cells in tissue culture was evaluated. Androgens (dihydrotestosterone or fluoxymesterone) were capable of stimulating the secretion rates for all three GCDFP's while showing a minimal trend toward slowing the growth rate of T47D cells. This is the first study which shows that androgens can specifically stimulate all three of the major breast GCDFP's concomitantly. Progesterone, and three synthetic progestins, all showed inhibition of the growth rate of T47D cells while causing enhancement of the secretion of GCDFP-15 and GCDFP-44, and only minimal effect on the secretion rate of GCDFP-24. Estradiol was essentially neutral to the growth rate of the T47D cells in our test system. Estradiol did cause a mild enhancement of GCDFP-44 secretion rate, with no appreciable effect on GCDFP-15 or GCDFP-24 secretion rates. These findings suggest that an androgenic stimulus may be involved in the secretion of GCDFP's associated with breast gross cystic disease.

Human Zn-alpha 2-glycoprotein cDNA cloning and expression analysis in benign and malignant breast tissues

Two cDNA clones coding for Zn-alpha 2-glycoprotein (Zn-alpha 2-gp) have been isolated from a human breast library and their nucleotide sequences determined. The deduced amino acid sequence contains the coding information for a hydrophobic signal peptide and the 278 residues of the mature protein. Comparison of this sequence with that from the protein purified from plasma reveals four differences: two amino acid changes (Gln-67 and Glu-222) and insertion of two residues (Ile-75 and Phe-76). Northern-blot analysis showed that the Zn-alpha 2-gp gene is expressed in liver and normal breast, but not in placenta, ovary and thyroid. A comparative analysis in mammary tissues from women with different diseases revealed enhanced expression of Zn-alpha 2-gp gene in benign breast lesions and a variable expression level in breast cancers.