Breast cancer cutaneous metastases are associated to uMUC1 and sialyl Lewis x and to highly malignant primary tumors

Breast cancer spreading to different organs have been related to different molecules and mechanisms, but cutaneous metastasis remains unexplored. Increasing evidence showed that MUC1 and some of its carbohydrate associated antigens may be implicated in breast cancer metastasis. In this study we analyzed these tumor markers in order to identify breast cancer cutaneous metastatic profiles. A cohort of 26 primary tumors from breast cancer patients with cutaneous metastases were included; also, cutaneous and lymphatic node metastatic samples and primary tumors from breast cancer patients without metastases were analysed. Immunohistochemical (IHC) studies demonstrated that both underglycosylated MUC1 (uMUC1) and sialyl Lewis x (sLex) to be positively associated with cutaneous metastatic primary tumors (p < 0.05). Notably, a high percentage of tumors with cutaneous metastases were characterized as triple negative and Her2+ tumors (37.5 % and 29 %, respectively). Some discordant results were found between primary tumors and their matched cutaneous metastases. To determine if MUC1 variants may be carriers of carbohydrate antigens, subcellular fractions from a cutaneous metastatic lesion were obtained, immunoprecipitated and analyzed by Western blot. We found that the isolated uMUC1 with a molecular weight of>200 kDa was also the site for binding of anti-sLex MAb; in coincidence, a high correlation of positive IHC expression of both markers was observed. Our findings confirm that breast cancer cutaneous metastases were associated to highly malignant primary tumors and sustain the hypothesis that u-MUC1 and sLe x may drive breast cancer cutaneous metastases.

Detection of Circulating Mammary Mucin (MUC1) and MUC1 Immune Complexes (MUC1-CIC) in Healthy Women

There is convincing epidemiological evidence that multiparity provides protection against the development of breast cancer. In the present study we evaluated the levels of MUC1 and MUC1 circulating immune complexes (MUC1-CIC) in 135 serum samples obtained from healthy women. The study population included 13 women who had never been pregnant, 31 primiparous pregnant women, 36 multiparous pregnant women who had lactated, 5 multiparous pregnant women who had never lactated, 24 multiparous non-pregnant women who were lactating at the time of the study, 24 multiparous non-pregnant women who had lactated, and 2 multiparous non-pregnant women who had never lactated. The purpose of this work was to detect MUC1 variations during pregnancy and lactation as well as to study the possible induction of a humoral immune response against MUC1 in these conditions. We employed ELISA techniques to measure MUC1 (CASA test) and MUC1-CIC (IgM and IgG) using two anti-MUC1 monoclonal antibodies (MAbs): C595 and SM3. Statistical analysis was performed using the ANOVA test. The pooled results pertaining to pregnant versus non-pregnant women were compared and significant differences were observed in MUC1 and MUC1-CIC-IgM levels detected with both MAbs; the MUC1-CIC-IgG levels detected with C595 were increased in the pregnant group while the MUC1-CIC-IgG levels detected with SM3 did not show any significant differences. When the results were compared between lactating and non-lactating women, no significant differences were found. In conclusion, MUC1 and MUC1-CIC-IgM, detected with both MAbs, and MUC1-CIC-IgG levels detected with the MAb C595 are apparently induced by pregnancy.

Temporal and spatial expression of Muc2 and Muc5ac mucins during rat respiratory and digestive tracts development

Secreted mucins constitute a crucial part of the gel that protects respiratory and digestive epithelia, being MUC2/Muc2 the predominant gel-forming mucin of the intestine while MUC5AC/Muc5ac is one of the gel-forming mucins most expressed at the airways. In this study, we have analyzed Muc2 and Muc5ac during rat development by using immunohistochemistry, Western blotting and RT-PCR. We demonstrated that rat Muc2 was expressed in fetal intestinal goblet cells of surface epithelium of villi and developing Lieberkühn crypts. In neonates and adults, Muc2 was expressed at luminal goblet cells of small and large intestine and at gastric mucous and glandular cells. Muc5ac protein was observed in embryonic gastric and lung samples; expression increased during development and postnatal and adult life. After birth, a low reaction was detected at the tracheal surface epithelium and glands, which increased in adults.

Spatiotemporal expression of Rhomboid domain containing 2 (Rhbdd2) during rat development

Over the last few years rhomboid genes have gained interest because of its association with cancer and neurodegenerative diseases. In previous studies, we demonstrated that human RHBDD2 is over-expressed in the advanced stages of breast and colorectal cancers, suggesting a favorable role in cell proliferation. So far little is known about the expression of RHBDD2 in other tissues and other species, and because of similarities between cancer and embryonic cells, this study focused on the evaluation of Rhbdd2 expression in embryonic and adult rat tissues. By IHC and RT-PCR, Rhbdd2 was identified in early stages of most tissues analyzed, with high expression in brain, spinal cord, kidney and embryonic skin. In adult tissues, the expression remained elevated while salivary glands became positive. Furthermore, Rhbdd2 showed a high expression in the most proliferative stages of the rat mammary gland. Indeed, similar findings were observed in the mouse mammary epithelial cell line HC11, in which Rhbdd2 resides in the Golgi apparatus, and at different stages of mouse mammary gland development. Therefore, Rhbdd2 would be implicated in embryonic and adult tissue proliferation.

Muc5ac mucin expression during rat skin development

Some mucin genes have been detected during human embryonic and fetal organ development; however, little is known about mucin expression in epidermal development, neither in humans nor in other species. The present research was developed to explore Muc5ac skin expression during pre- and post-natal rat development. Immunohistochemistry (IHC), Western blotting (WB) and RT-PCR were employed. By IHC, Muc5ac protein was found early in embryonic epidermis from day 13 of gestation until seven days after birth when the surface epidermis became negative and the reaction was restricted to secreting sebum cells. In coincidence with IHC findings, WB analysis showed a band at approximately 200KDa at the same periods of development. Results were also confirmed by RT-PCR.

Muc5ac expression in rat embryonic epidermis suggests that Muc5ac may play a protective role in embryonic skin previous to birth which may be replaced by pile covering. To our knowledge, this is the first report that confirmed Muc5ac expression during skin development.

Identification of signaling pathways modulated by RHBDD2 in breast cancer cells: a link to the unfolded protein response

Rhomboid domain containing 2 (RHBDD2) was previously observed overexpressed and amplified in breast cancer samples. In order to identify biological pathways modulated by RHBDD2, gene expression profiles of RHBDD2 silenced breast cancer cells were analyzed using whole genome human microarray. Among the statistically significant overrepresented biological processes, we found protein metabolism—with the associated ontological terms folding , ubiquitination, and proteosomal degradation—cell death, cell cycle, and oxidative phosphorylation. In addition, we performed an in silico analysis searching for RHBDD2 co-expressed genes in several human tissues. Interestingly, the functional analysis of these genes showed similar results to those obtained with the microarray data, with negative regulation of protein metabolism and oxidative phosphorylation as the most enriched gene ontology terms. These data led us to hypothesize that RHBDD2 might be involved in endoplasmic reticulum (ER) stress response. Thus, we specifically analyzed the unfolding protein response (UPR) of the ER stress process. We used a lentivirus-based approach for stable silencing of RHBDD2 mRNA in the T47D breast cancer cell line, and we examined the transcriptional consequences on UPR genes as well as the phenotypic effects on migration and proliferation processes. By employing dithiothreitol as an UPR inducer, we observed that cells with silenced RHBDD2 showed increased expression of ATF6, IRE1, PERK, CRT, BiP, ATF4, and CHOP (p <0.01). We also observed that RHBDD2 silencing inhibited colony formation and decreased cell migration. Based on these studies, we hypothesize that RHBDD2 overexpression in breast cancer could represent an adaptive phenotype to the stressful tumor microenvironment by modulating the ER stress response.

IDO is highly expressed in breast cancer and breast cancer-derived circulating microvesicles and associated to aggressive types of tumors by in silico analysis

Indoleamine-2,3-dioxygenase (IDO) has been established as a normal mechanism of peripheral tolerance and immunosuppression. Besides, malignant tumors release microvesicles (MV) related with tumor dissemination. The aims of this study were to determine the expression of IDO in breast cancer and circulating microvesicles from breast cancer patients and to perform an in silico analysis to find genes co-expressed to IDO. One hundred and twenty-two tissue and serum breast samples (91 malignant, 21 benign, and 10 normal), and MCF7, MDA-MB-231, and T47D breast cancer cell lines were included. Standard immunohistochemistry (IHC), immunocytochemistry (ICC), Western blot (WB), and RT-PCR were employed. Microvesicle isolation from plasma samples was obtained by serial centrifugation and ultracentrifugation. By IHC, 60 % breast cancer, 43 % benign, and 20 % normal samples were positive. Significant differences were found among normal, benign, and malignant samples. Breast cancer stages I, II, and III expressed IDO in 42, 66, and 71 % of samples, respectively, while breast cancer cell lines also reacted; by WB, 9/25 microvesicles fractions showed bands at 42 kD. In silico analysis of IDO 1 gene expression in breast cancer showed its association with several genes related to immune response and apoptosis. Moreover, IDO and co-expressed genes were found predominately in basal and erbB2 subtypes. The cumulative data indicate a high expression of IDO in breast cancer which increased with higher stages. Furthermore, IDO was found in association with circulating breast cancer MV, while experimental and in silico gene expression revealed that IDO was mainly expressed in a triple-negative subgroup.

Rhomboid family gene expression profiling in breast normal tissue and tumor samples

Rhomboid is an evolutionary conserved and functionally diversified group of proteins composed of proteolytically active and inactive members that are involved in the modulation of multiple biological processes such as epidermal growth factor receptor signaling pathway, endoplasmic reticulum-associated degradation, cell death, and proliferation. Recently, several human rhomboid genes have been associated with the development of chronic myeloid leukemia and pituitary, colorectal, ovarian, and breast cancers. In this study, we evaluated the mRNA and protein expression profiles of rhomboid genes in cancer cell lines and breast tissue/tumor samples. In silico analysis of publicly available gene expression datasets showed that different rhomboid genes are specifically expressed according to the breast cancer intrinsic subtypes. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis showed a significant RHBDD2 mRNA overexpression in advanced breast cancer compared with normal tissue samples (p = 0.012). In addition, we found that RHBDL2 and PARL mRNA expression was associated with a low/intermediate histologic tumor grade (p = 0.024 and p = 0.015, respectively). Immunohistochemistry analysis showed a significant increase of RHBDD2 protein expression in association with breast cancer samples negative for progesterone receptor (p = 0.015). Moreover, protein expression analysis corroborated the quantitative RT-PCR results, indicating that breast primary tumors belonging to patients with a more disseminated disease expressed significantly increased levels of RHBDD2 protein compared with less disseminated tumors (p = 0.01).

Abstract P3-07-13: Importance of socioeconomic status in relation to breast cancer risk and prognostic factors in Argentina

In Argentina, there are no studies evaluating neither breast cancer screening nor risk and prognostic factors in relation to socioeconomic status among women in metropolitan areas. Taking into account that Argentina presents social and economical disparities and that there is a mixture of features of both developed and developing societies, it is interesting to compare prognostic and risk factors in disadvantaged and advantaged women as it would clarify the influence of socioeconomic factors in breast cancer biology. The purpose of this study was to compare risk and prognostic factors of invasive breast cancer in two different Argentine populations. Study participants and data collection. A total of 625 women who had a histologically confirmed diagnosis of invasive primary breast cancer were included; 270 patients belonged to a private clinic of the city of La Plata (province of Buenos Aires) belonging to an Advantaged Population (AP) and 355 patients belonged to a public hospital of the city of Neuquén (province of Neuquén, Patagonia) belonging to a Disadvantaged Population (DP). Women of these geographical regions and first diagnosed with invasive primary breast carcinoma from 2002 until 2007 were eligible as cases. There were no racial or ethnic differences between the two groups of women; all of them were born in Argentina. Risk factors included age at diagnosis, menarche and menopause status, breastfeeding and parity, while prognostic factors were: disease stage, number of metastatic lymph nodes, tumor size, histological and nuclear grade, vascular invasion, ER, PR, and Her2neu statuses.

Methods: Statistical analysis included frequency analysis and ANOVA (p &lt; 0.05).

Results: A remarkable difference between the two populations was found: the age at diagnosis was significantly lower in DP than in AP: 63% of DP versus 44% of AP was &lt;55 years old. AP stage III was observed at X = 49 years old versus DP at X = 54 years old; cutaneous and/or thoracic wall invasion was found at diagnosis in 15.4% of DP, while it was absent in all APs. Both groups showed advanced stages in younger patients. In general, tumor size versus age showed a negative relationship (p &lt; 0.04); this observation was only significant for AP (p &lt; 0.02). ER, PR expression, and Her2neu status presented differences between the two populations. Percentage of AP patients with positive ER were 78.8%, positive PR: 79.5%; while Her2-neu positive status was found in 5.3%. In the case of DP patients, positive percentages were: ER: 66.3%, PR: 51.2%; and finally Her2-neu: 38.8%. Histological and nuclear grade DP compared to AP were significantly higher, while vascular and lymphatic invasion showed the inverse DP: 30% versus AP: 18%, p &lt; 0.01. Taking into account the number of children, significant differences between groups were found: DP, 2.8+/−0.11 while AP, 1.9+/−0.13 (media +/− standard error). In general, it was observed that patients who had breastfed presented lower number of metastatic lymph nodes than those who had not.

Conclusions: Patients belonging to these two different geographical regions constitute two different populations. Breastfeeding and number of children, considered in relation to socio-economic features, are important risk factors of invasive breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-07-13.

Immunohistochemical evidence of Muc1 expression during rat embryonic development

During embryonic development, studies on mouse and human embryos have established that Muc1/MUC1 expression coincides with the onset of epithelial sheet and glandular formation. This study aimed therefore at evaluating the temporal and spatial expression of Muc1 at different stages of rat development. In this report, 80 animals were included: 64 rat foetuses at 13, 14, 15, 16, 17, 18, 19 and 20 days of gestation from pregnant females (WKAH/Hok), 8 embryos each stage. Standard immunohistochemistry was performed using anti-MUC1 cytoplasmic tail polyclonal antibody (CT33). The reaction was considered positive when more than 5% of the cells were stained; reaction patterns were: L = linear, membrane, C = cytoplasmic and M = mixed; nuclear staining was also recorded. Intensity was graded as negative (−), low (+), moderate (++) and strong (+++). Muc1 expression was observed with a low intensity on 13th day (13 D) in the stomach, lung and kidney; at 14 d, small intestine and pancreas were also reactive; at 16 D, liver and esophagus and at 18 D, trachea and salivary glands. During the development, intensity increased while the pattern of expression changed: at the first days of gestation, it was predominantly linear and apical while during further development an increase in cytoplasmic expression was observed. Trachea, stomach, kidney and lung epithelia were the more reactive tissues. In specimens belonging to neonates and adults, all tissues analyzed showed similar Muc1 expression. The findings of this study assess that Muc1 is highly expressed in the epithelial rat embryonic development.

MUC1 oncogene amplification correlates with protein overexpression in invasive breast carcinoma cells

The MUC1 gene is aberrantly overexpressed in approximately 90% of human breast cancers. Several studies have shown that MUC1 overexpression is due to transcriptional regulatory events. However, the importance of gene amplification as a mechanism leading to the increase of MUC1 expression in breast cancer has been poorly characterized. The aim of this study was to evaluate the role of MUC1 gene amplification and protein expression in human breast cancer development. By means of real-time quantitative polymerase chain reaction and immunohistochemical methods, 83 breast tissue samples were analyzed for MUC1 gene amplification and protein expression. This analysis showed MUC1 genomic amplification and a positive association with the histopathological group in 12% (1 out of 8) of benign lesions and 38% (23 out of 60) of primary invasive breast carcinoma samples (P = 0.004). Array-comparative genomic hybridization meta-analysis of 886 primary invasive breast carcinomas obtained from 22 studies showed MUC1 genomic gain in 43.7% (387 out of 886) of the samples. Moreover, we identified a highly statistical significant association between MUC1 gene amplification and MUC1 protein expression assessed by immunohistochemistry and Western blot test (P < 0.0001). In conclusion, this study demonstrated that MUC1 copy number increases from normal breast tissue to primary invasive breast carcinomas in correlation with MUC1 protein expression.

Rhomboid domain containing 2 (RHBDD2): a novel cancer-related gene over-expressed in breast cancer

In the course of breast cancer global gene expression studies, we identified an uncharacterized gene known as RHBDD2 (Rhomboid domain containing 2) to be markedly over-expressed in primary tumors from patients with recurrent disease. In this study, we identified RHBDD2 mRNA and protein expression significantly elevated in breast carcinomas compared with normal breast samples as analyzed by SAGE (n=46) and immunohistochemistry (n=213). Interestingly, specimens displaying RHBDD2 over-expression were predominantly advanced stage III breast carcinomas (p=0.001). Western-blot, RT-PCR and cDNA sequencing analyses allowed us to identify two RHBDD2 alternatively spliced mRNA isoforms expressed in breast cancer cell lines. We further investigated the occurrence and frequency of gene amplification and over-expression affecting RHBDD2 in 131 breast samples. RHBDD2 gene amplification was detected in 21% of 98 invasive breast carcinomas analyzed. However, no RHBDD2 amplification was detected in normal breast tissues (n=17) or breast benign lesions (n=16) (p=0.014). Interestingly, siRNA-mediated silencing of RHBDD2 expression results in a decrease of MCF7 breast cancer cells proliferation compared with the corresponding controls (p=0.001). In addition, analysis of publicly available gene expression data showed a strong association between high RHBDD2 expression and decreased overall survival (p=0.0023), relapse-free survival (p=0.0013), and metastasis-free interval (p=0.006) in patients with primary ER-negative breast carcinomas. In conclusion, our findings suggest that RHBDD2 over-expression behaves as an indicator of poor prognosis and may play a role facilitating breast cancer progression.

MUC1 cytoplasmic tail detection using CT33 polyclonal and CT2 monoclonal antibodies in breast and colorectal tissue

The immunohistochemical detection (IHC) of MUC1-CT employing a polyclonal antibody (CT33) in relation to CT2 monoclonal antibody (MAb) was analyzed. Western blot (WB) was used to determine the molecular mass of CT.

MATERIALS AND METHODS

We studied 163 breast and 89 colorectal cancer specimens, 10 breast and 14 colorectal benign conditions, and 12 breast and 20 colorectal normal samples. From each tumor sample, subcellular fractions were obtained and analyzed by SDS-PAGE and WB. A nonparametric statistical analysis was employed; data were standardized and a Kendall-Tau correlation was applied.

RESULTS

By IHC, 146/163 (90%) and 151/163 (93%) of breast cancer were positive with CT33 and CT2, respectively; a statistically significant correlation was obtained (t=0.5199). Seven out of ten (70%) benign breast specimens were positive with CT33 while all samples stained with CT2; in normal breast sample tissues, all were positive with both Abs. In colorectal cancer samples, both antibodies stained 47/89 (53%) samples; CT2 reacted in 13/14 (93%) of benign samples while CT33 showed a positive reaction in 9/14 (64%) of benign specimens. In normal samples, CT2 showed staining in 17/20 (85%) of samples and CT33 was reactive in 12/20 (60%). By WB, in breast and colorectal cancer samples, similar results were obtained with both antibodies: a main band at about 30kDa which represents the smaller subunit.

CONCLUSION

CT33 polyclonal antibody has demonstrated its efficacy to detect MUC1 in breast and colorectal cancer tissues with similar reactivity to CT2. It is worthwhile to affirm that CT33 is a good indicator of MUC1 expression.

Alpha 1-acid glycoprotein (AGP): a possible carrier of sialyl lewis X (slewis X) antigen in colorectal carcinoma

OBJECTIVES

1- to detect alpha 1-acid glycoprotein (AGP) and sialyl Lewis x (sLex) in colorectal malignant, benign and normal samples; 2- to isolate AGP from colorectal cancer and 3- to study its immunoreactivity with an anti-sLex monoclonal antibody (MAb).

MATERIALS AND METHODS

tissue and serum samples from 88 patients with colorectal cancer, 22 adenomas and 23 normal were included. Expression of AGP and sLex was studied by immunohistochemistry (IHC); isolation approach: AGP was precipitated with ammonium sulphate and immunoprecipitated with anti-AGP MAb. The immune complex formed was isolated by protein A-Sepharose CL-4B affinity chromatography and further eluted; fractions were analysed by SDS-PAGE and Western-blot. Statistical analysis was performed by means of Principal Component Analysis.

RESULTS

By Western blot employing anti-AGP MAb and sLex MAbs, isolated fractions from malignant samples showed a band at about 45 kD. IHC revealed that AGP was expressed in 70% of colorectal carcinoma samples, 50% of benign and 35% of normals. SLex was detected in 31% of malignant samples, 41% of benign and in one normal sample. In malignant samples, AGP reaction comprised the whole specimen with a strong and homogeneous staining while normal and benign samples showed a restricted reaction. In cancer, sLex expression consisted in an intense reactivity in membrane, cellular debris and some cytoplasmic foci while normal and benign samples were occasionally stained. A statistically significant positive correlation was found between AGP and sLex expression. Serum AGP levels were measured by radial immunodiffusion and statistical comparative analysis with tissue expression did not show a correlation between both parameters.

CONCLUSION

AGP may constitute a carrier of sLex in colorectal cancer.

Antigenic differences between metastatic cells in bone marrow and primary tumours and the anti-MUC1 humoral immune response induced in breast cancer patients

The dissemination of a malignant neoplasia is a complex process, which requires a set of molecules that remains unknown. It has been suggested that mucins and their carbohydrate-associated antigens may be implicated in tumour spreading which may be also influenced by an anti-MUC1 immune response. In this pilot study, we report the pattern of carbohydrate and peptidic MUC1-associated epitopes on carcinoma cells isolated from bone marrow (BM), taking into account primary tumour histopathologic features. We also bring information about the anti-MUC1 humoral response in these patients. Seventeen patients with invasive breast carcinoma were included. A sample of the primary tumour, a serum sample and a BM aspirate were obtained from each patient. Clinical features studied were tumour size, number of metastatic nodes, histological type and disease stage. Standard immunohistochemistry was performed with antigenic retrieval using different monoclonal antibodies (MAbs): anti carbohydrate antigens: Lewis x (KM380), sLewis x (KM93), Lewis y (C14) and Tn, anti-MUC1 peptide core MAbs: C595, HMFG2 and SM3, anti-cytokeratins, anti-protoncogenes ErbB2 and ErbB3 (IgG) MAbs and also anti-CD34 and anti-CD45 MAbs. ELISA techniques were employed to study circulating MUC1 as well as free and complexed anti-MUC1 antibodies. Immunohistochemical results showed that carbohydrate antigenic expression increases in BM neoplastic cells compared to the original tumours. However, we were not able to demonstrate that a humoral immune response to MUC1 has been induced in these patients. Finally, the employed procedures allow the selective immortalisation of micrometastatic carcinoma cells since short-term cell lines were established.

MUC1 mucin and carbohydrate associated antigens as tumor markers in head and neck squamous cell carcinoma

An immunological analysis to study MUC1 mucin core protein and carbohydrate associated antigens as tissue tumor markers in head and neck carcinoma was performed. Twenty nine patients with the following tumor localizations were included: tongue (n=10), larynx (n=8), oral cavity (n=4), maxillary sinus (n=3), tonsillar ring (n=3) and pharynx (n=1); seven samples of epithelium obtained from normal organs at the same localizations were studied as controls. Immunohistochemical analysis was performed following standard procedures and reaction was graded according to staining intensity and distribution. From each tissue section, membrane, cytoplasmic and nuclear moieties were obtained by differential centrifugation with subsequent fractionation by density gradient centrifugation (6M guanidium chloride-CsCl); subcellular moieties and CsCl derived fractions were analyzed by immunoblotting. Monoclonal antibodies (MAbs) reacting with the core protein of MUCI (C595) and associated carbohydrate antigens were: Tn, 83D4 MAb; Lewis y antigen (Le y), C14 MAb; Lewis x antigen (Le x), KM380 MAb and sialyl Lewis x (sLe x), KM93 MAb. Statistical analysis was undertaken by Spearman rank correlation. In tumor samples, the immunohistochemical identification of MUCl core protein and associated antigens was extended; differences were found in the pattern and intensity of expression; results were corroborated by immunoblotting although in a few samples there was not coincidence between both methods. Localization, tumor mass or node involvement did not show significant differences for any of the antigens studied.

CONCLUSIONS

1) head and neck carcinoma expressed MUCI and associated carbohydrate antigens in high levels; 2) no relationship between antigenic expression and tumor status was found.

Humoral immune response induced by the protein core of MUC1 mucin in pregnant and healthy women

Serum levels of MUC1 and antibodies (Abs) against MUC1 (IgG and IgM-MUC1) were evaluated in healthy women related to pregnancy and lactation status. A total of 149 serum samples were obtained from: nulliparous, primiparous pregnant, multiparous pregnant that have lactated, multiparous pregnant without lactation, multiparous non-pregnant actual lactating, multiparous non-pregnant that have lactated and finally, multiparous non-pregnant women without lactation. In all assays, we included pre- and post-serum samples belonging to a breast cancer patient vaccinated with a MUC1 derived peptide. CASA test was employed to measure MUC1 while IgG- and IgM-MUC1 serum Abs were evaluated with an ELISA using a 100 mer peptide as catcher. In all groups, mean IgM levels were higher than IgG mean values; when samples were grouped in pregnants versus non-pregnants, a significant difference was detected with both Abs, being raised in non-pregnants. When samples were grouped in lactating versus non-lactating a significant difference was detected with IgG-MUC1, being raised in lactating women while no significant difference was found with IgM-MUC1. The evaluation of serum MUC1 levels confirmed previous results since a significant difference between pregnant versus non-pregnant groups was found while lactating versus non-lactating samples did not.

CONCLUSIONS

(i) Increased MUC1 serum levels are apparently associated with pregnancy but not with lactation; (ii) MUC1 Abs are mainly associated with lactation and with non-pregnant status. These results may be considered a contribution on studies about protection against breast cancer induced by pregnancy and lactation.

Establishment and characterization of a cell line (T201) derived from a human larynx squamous cell carcinoma

The purpose of this report was the initiation and further maintenance of tumor cells from a primary larynx squamous cell carcinoma. A tumor fragment was mechanically dissociated, the cells were grown in RPMI medium, being the primary culture dependent on the presence of epidermal growth factor and insulin; during subsequent passages the adaptation to conventional growth conditions was obtained. Cells grew in monolayer with an epitheliod shape, showing a pavement-like arrangement; at confluence, cells piled up without contact inhibition maintaining the same morphology. Population doubling time was about 48 h with a colony-forming efficiency of 10%. Immunocytochemical characterization was performed with a panel of monoclonal antibodies reactive against tumor associated antigens, including mucin glycoproteins and related carbohydrate antigens, carcinoembryonic antigen (CEA), p53 as well as cytokeratins, vimentin and desmin. T201 expressed CEA, sialyl Lewis x, Lewis x, Lewis y, MUC1 mucin, Tn hapten, p53, vimentin and cytokeratins. On the other hand, a modal chromosome diploid number of 46 occurring in 74% of cells was detected. Present data confirmed that the methodology employed was adequate for the establishment and characterization of a new cell line which can provide a useful model to study biological and immunological aspects of larynx squamous cell carcinoma.

Association of a alpha1 acidic glycoprotein and squamous cell carcinoma of the head and neck

Serum from patients with different malignancies contain an abnormal concentration of a a1-acidic-glycoprotein (AAG) and also, increased levels of AAG are associated with the presence of tumor mass. In the present report, serum levels of AAG were measured by radial immunodiffusion in squamous cell carcinoma of the head and neck (SCCHN) patients taking into account disease status parameters such as tumor localization, stage and extension of disease. Immunohistochemical methods, SDS-PAGE and Western-blotting were employed to study the expression of AAG and a carbohydrate related antigen (sialyl Lewis x) in tumor tissues and derived fractions. AAG showed abnormal levels in 7/15 oral cavity tumor patients sera, 2/5 oropharynx and 5/10 larynx tumors; increased AAG serum levels belonged to patients with disseminated disease. On the other hand, the presence of AAG and sialyl Lewis x were demonstrated in carcinoma cells and in derived fractions from tumor tissues belonging to patients with elevated AAG serum levels. In the present study, we have found elevated levels of AAG in serum samples from SCCHN patients; these neoplastic cells are capable to express AAG.

Detection and isolation of MUC1 mucin from larynx squamous cell carcinoma

The progression from uncontrolled cell proliferation to invasion and metastasis of epithelial tumors is partially understood. Alteration of epithelial mucin expression have been described in different malignant localizations but only few attempts have been made to identify mucin expression in malignant laryngeal tumors. In the present report, results are shown of studies on the expression of mucins and carbohydrate related antigens in laryngeal cancer and on the isolation of MUC1 mucin from this tumor tissue. Malignant laryngeal specimens were processed for immunohistochemical analysis and for extranuclear membrane fractions (ENM) which were obtained by ultracentrifugation. Subsequently, ENM samples were centrifuged in density-gradient; the analysis of fractions was performed by means of SDS-PAGE and Western-blotting. The panel of monoclonal antibodies (MAbs) included anti MUC1 mucin, anti Lewis x, anti sialyl Lewis x, anti Lewis y, anti MUC-5B, anti oral mucin (gp230), anti Tn hapten, anti p53 and anti cytokeratins. By immunohistochemistry, it was possible to detect MUC1 mucin, Lewis x and Lewis y showing strong reactions while sialyl-Lewis x and Tn antigen only reacted weakly in a few cells; cytokeratins were detected in all samples. In ENM derived fractions obtained by CsCl centrifugation, MUC1 was demonstrated by Western blotting.

CONCLUSIONS

(1) laryngeal cancer antigenic expression comprises mostly MUC1 mucin, Lewis x, Lewis y as well as Tn antigen and (2) the methodology here employed is useful to isolate MUC1 from tumor samples.

Identification and characterization of different subpopulations in a human lung adenocarcinoma cell line (A549)

The morphology, cell growth, antigenic expression and tumorigenicity of cell subpopulations from the A549 lung adenocarcinoma isolated by Percoll gradient separation have been analysed. Four subpopulations were obtained (subpopulations A, B, C and D). Immunocytochemical analysis of several antigens was performed with monoclonal antibodies (MAbs): MUC1 mucin (C595, HMFG1 and HMFG2), MUC5B (PANH2); gp230 (PANH4); carbohydrate antigens including sialyl Lewis x (KM93), Tn antigen (83D4), Lewis y (C14); 5, 6, 8, 17 and 19 cytokeratins and p53. The cell population D tended to form cell aggregates that piled up on the monolayer similar to overgrowth cultures of the A549 parental cell line, whereas A, B and C cell subpopulations formed well spread monolayers. Both parental A549 and subpopulation D secreted abundant mucus. The topographic distribution and secretion production were correlated with tumorigenic assays since only subpopulation D grew in nude mice exhibiting reduced latency period; these characteristics correlated with the fast growth of the subpopulation D in vitro. Immunocytochemical analysis demonstrated that subpopulation D showed greater expression of MUC1 mucin and carbohydrate antigens such as Tn antigen, sialyl Lewis x and Lewis y and less expression of cytokeratins, p53, MUC5B and gp230; conversely, subpopulations A, B and C showed the opposite antigenic profile. Our results illustrate heterogeneity in the A549 cell line; subpopulations A, B and C retained characteristics of more differentiated adenocarcinoma while subpopulation D displayed features of a less differentiated tumor line.

Assessment of methods for primary tissue culture of human breast epithelia

A serie of 29 human normal, benign and malignant breast tissues were cultivated in an attempt to isolate and propagate primary breast epithelial cells in vitro. Explants methodology as well as disaggregation techniques (enzymatic and mechanical) were employed to obtain better culture conditions. Cells derived from breast malignant tissue were propagated in an appropriate and survived in culture for at least 6 months, exhibiting a marked preference to grow in suspension (independent anchorage). Tumorigenicity assays in nude mice were performed with malignant cells obtained from primary culture cells as well as with cells achieved from successive passages. The rate of long time cell survival from malignant and non-malignant tissues demonstrated the accuracy of the methodology but it also emphasised the need for improving technology to obtain cell lines with long survival.

Immunohistopathological characterizatin of spontaneous metastases in a human lung mucoepidermoid adenocarcinoma (HLMC) xenograft

The most common clinical form of lung cancer is a disseminated disease with distant metastases; several years of cancer progression precede presentation, and this ultimately limits the efficacy of curative therapy. In this immunohistochemical study, we examined a mucinous adenocarcinoma cell line, maintained by xenogeneic transplantation, and a spontaneous metastatic variant which produces distant tumors (in liver, spleen and kidney). The aim was to investigate possible parameters which characterize the metastatic process. Histopathological comparison between the two subcutaneous transplanted tumor lines showed that both lines presented a similar cellular morphology, a different pattern of cellular growth and an increased vascularization in the metastatic line with respect to its parent. All the tumor sections expressed differential immune reactivity with monoclonal antibodies against Lewis y (MAb C14), sialyl-Lewis x (MAb SNH3) and Lewis x (MAb FH2) determinants. Neither expressed MUC 1 mucins detectable with monoclonal antibodies reactive with the mucin protein core (MAbs C595 and SM3) nor was carcinoembryonic antigen (MAb C365) expressed. Neoplastic cells were reactive with an anti-pan cytokeratin monoclonal antibody confirming their epithelial histogenesis. Our findings have been evaluated with respect to defining metastatic phenotypes in lung cancer by examination of distinct histopathological and immunological parameters.

Expression of tumour associated antigens in normal, benign and malignant human mammary epithelial tissue: a comparative immunohistochemical study

Breast carcinoma cells may express a variety of clinically relevant epitopes, some of which are associated with aberrant glycosylation of MUC1 mucin molecules, as well as determinants which are commonly expressed on their normal molecular counterparts. The present investigation is primarily an immunochemical analysis of MUC1 epitopes and other tumour associated antigenic determinants, as defined by their reaction with monoclonal antibodies and expressed in normal, benign and malignant epithelia. It was determined that malignant tissues of the breast expressed MUC1 mucin, as well as the Le(y) hapten and CEA, at different intensities, cellular distribution and patterns and percentages of positively stained cells. Conversely, benign tissues expressed a low intensity of MUC1 which was restricted to apical cell surface membranes and lumen debris; a similar pattern was found in some normal breast sections. It was concluded that MUC1 mucin exhibits heterogeneous antigenicity (as defined by its reactivity with a panel of related anti-MUC1 monoclonal antibodies) which is predominantly related to the progression of malignant disease. Le(y) is a marker of breast neoplasia, while CEA was found on only a small proportion of tumours. These immunohistochemical findings are considered in the context of improving breast cancer diagnosis and therapy.

Breast cancer associated mucin: a review

Breast mucins are expressed by malignant epithelial cells and they elicit an immune reaction. The up-regulation of mucin expression is association with tumour invasion, this mucin called MUC-1 reduces the cell-cell interaction facilitating cell detachment. The MUC-1 gene product, known as polymorphic epithelial mucin is a transmembrane high molecular weight glycoprotein. The molecule of MUC-1 has a central polypeptidic core with a carbohydrate linked in O-linkage to serines and threonines. The carbohydrate side chain epitope of MUC-1 molecule produced by breast cancer cells is heavily sialylated, giving their physical properties and increasing their immunogenicity. The development of monoclonal antibodies (MAb) has led to study the MUC-1 in subcellular extracts, tissues and culture supernatants from breast cancer and also colorectal carcinoma. The pattern of tumour cell staining with labeled MAb varies according with the grade of malignancy; these MAb bind either to peptide sequence and/or to the glycosylated epitopes. MUC-1 has a clinical relevance because serum concentrations may be useful for monitoring the response to therapy and progress of disease. MUC-1 epitope masking has been described since specific antibodies can combine with them forming immune complexes. Finally, mucins have been considered to develop vaccines against cancer, targeting specific carbohydrate and mucin epitopes.

Identification of acute-phase proteins (APP) in circulating immune complexes (CIC) in esophageal cancer patients' sera

The occurrence of increased circulating immune complexes (CIC) in sera of patients with esophageal cancer and their usefulness for diagnosis and prognosis have not been demonstrated. Circulating acute-phase proteins (APP) related to esophageal cancer have been described but without any association with CIC. This is a study to measure CIC, C-reactive protein (CRP), and alpha 1-acidic glycoprotein (AAG) in pretreatment esophageal cancer sera and to analyze the presence of both APP associated with these CIC. Increased CIC levels were found in 57% of sera from esophageal cancer patients; elevated CRP was detected in 87% and AAG in 47%. Western blot analysis showed the presence of CRP and AAG in CIC-derived fractions. We conclude that: (1) CIC, CRP, and AAG are elevated in esophageal cancer sera; (2) they may be considered possible useful clinical parameters in pretreatment esophageal cancer patients; (3) these APPs appear in CIC precipitates and may possibly be involved in their composition.

Expression of monoclonal-antibody-defined antigens in fractions isolated from human breast carcinomas and patients' serum

The aim of this study was to examine tissue from patients with breast carcinoma or benign breast disease for the presence of monoclonal-antibody-defined antigens, including the MUC1 mucin and carcinoembryonic antigen CEA. The tests were performed by sodium dodecyl sulphate/polyacrylamide gel electrophoretic separation of proteins, electrophoretic transfer to nitrocellulose membranes and immunostaining with the monoclonal antibodies. Some of the antigens identified are known to circulate at high levels in some but not necessarily all, breast carcinoma patients. Serum from a panel of ten breast cancer patients was subjected to a fractionation procedure designed to release antigen from immune complexes, and again these samples were analysed for the presence of monoclonal-antibody-defined antigens. A high frequency of positive reactions was detected by the anti-MUC1 monoclonal antibody C595 with both breast carcinoma subcellular membrane fractions as well as antigen fractions eluted from circulating immune complexes. No reactions were observed with equivalent materials from benign breast disease samples. The findings illustrate the variability in antigen expression between breast tumours. The data also indicate that a proportion of patients respond to their tumour by the production of antibodies that recognise the MUC1 antigen in their circulation.

Identification of myelin basic proteins in circulating immune complexes associated with lepromatous leprosy

Circulating immune complexes (CIC) were first measured in lepromatous patients (LL) by the 125I-C1q binding assay and the polyethylene glycol (PEG) precipitation test. High levels were found by both methods (95 and 90% of positives, respectively). LL-CIC were investigated for the presence of neural antigens. CIC were precipitated in 3.5% PEG, filtered through protein A-Sepharose affinity chromatography, eluted with glycine-HCl, pH 2.8, and washed with PBS; fractions after CIC dissociation were studied by SDS-PAGE and Western blotting. The LL-CIC PEG precipitates and the glycine-HCl eluates were positive in 76 and 71% respectively against anti-myelin basic proteins (MBP) monoclonal antibody, showing a single band at 15-25 kDa similar to the one obtained incubating MBP with anti-MBP. No reaction was detected with CIC-PBS fractions; strips were incubated with other anti-neural antibodies such as anti-glial fibrillary acidic proteins, anti-S-100, and anti-neurofilaments, without any reactivity. Our results demonstrate that LL-CIC contain MBP as an antigen; its significance could be related to the pathogenesis of leprosy since the liberation of MBP after Mycobacterium leprae nerve damage may elicit anti-MBP autoantibodies to myelin breakdown, which reacts with peripheral nerve MBP inducing CIC formation. This mechanism may be important in demyelination and destruction of nerve in leprosy.

Clinical importance of circulating immune complexes in human acute lymphoblastic leukemia

A total of 122 sera from acute lymphoblastic leukemia (ALL) patients were analyzed for circulating immune complexes (CIC) by two methods: the 125I-Clq binding assay and the polyethylene glycol precipitation test (PEG). The results were correlated with induction, remission and relapse stages of the disease. Using the first method the levels of CIC in induction were 15.18 +/- 9.15, with 19/29 positive cases (65.50%), P less than 0.001 compared with controls. In the remission phase the levels were 9.02 +/- 5.62, 11/45 (24.49%) nonsignificant P value, and in relapse they were 16.14 +/- 11.17 28/48 (58.33%) P less than 0.001. The PEG precipitation test results were: 0.33 +/- 0.10, 8/22 (36.36%); 0.24 +/- 0.11, 10/48 (20.83%) and 0.28 +/- 0.10, 6/28 (21.42%), respectively. Thus the values of CIC as measured by PEG in the three clinical of phases ALL did not differ significantly from controls. This contrasts with results obtained by the radioiodinated C1q binding assay, where the incidence of positive values was significantly higher in induction and in relapse and lower in the remission phase. These observations were extended in sequential vertical studies performed in a group of patients. These results suggest that raised CIC detected by the 125I-C1q method may reflect a progressive state in ALL and that quantitation of these immune complexes may provide an adequate biochemical marker for prognosis.

Immune complexes in human malignant tumours. A review

This paper is a review on immune complexes in malignant tumours. High levels of immune complexes have been detected in the serum of patients with malignant solid tumours, leukemias and lymphomas. These studies were performed using non-specific methods. Results obtained by different laboratories are in general coincident; elevated levels of immune complexes in pre-treatment samples and in recurrent disease and, normal values in post-treatment studies indicating a disease free state. Nevertheless, there are certain variations among the results obtained by different techniques suggesting the necessity to check various methods for each tumour type. Although there is no clear evidence that immune complexes in cancer patients contain tumor related products, the current status of clinical research suggests the potential of circulating immune complexes assays for monitoring malignant diseases.

Antibodies presumably cross-reacting with mouse retrovirus type B and C in the sera of both leukemia-lymphoma and mammary cancer patients

In the mouse, retrovirus B and C are causal agents of mammary cancer and leukemia, respectively. In previous work it was demonstrated that sera of leukemia-lymphoma patients possess antibodies which react with antigenic determinants of Type C virus present on AKR-lymphoma and AKR-thymus targets. The object of this paper was to determine whether these antibodies also reacted with Type B viral antigens present on a virus-induced BALB-mammary carcinoma; at the same time a comparative study was carried out with sera of breast cancer patients. A total of 325 sera were obtained from 277 leukemia-lymphoma cases under protocol treatment: 232 acute lymphoid leukemia, 23 acute myeloid leukemia, 15 chronic myeloid leukemia and 55 Hodgkin lymphoma sera. A total of 240 sera were obtained from breast cancer patients at the time of diagnosis and 196 sera from normal blood donors served as controls. Using indirect immunofluorescence with labeled anti-human IgG and the murine targets, antibodies were encountered in a high percentage of cancer cases and were consistently absent in normal sera. The results confirm the presence of antibodies reacting with murine Type C virus in leukemia-lymphoma cases and indicate the presence of antibodies reacting to both Type B and C retroviruses in the sera of breast cancer patients.