Effects of lymphocytes and fibroblasts on the growth of human mammary carcinoma cells studied in short-term primary cultures

Molecular Insights Into the Relationship Between Autoimmune Thyroid Diseases and Breast Cancer: A Critical Perspective on Autoimmunity and ER Stress

The etiopathologies behind autoimmune thyroid diseases (AITDs) unravel misbehavior of immune components leading to the corruption of immune homeostasis where thyroid autoantigens turn foe to the self. In AITDs lymphocytic infiltration in the thyroid shows up a deranged immune system charging the follicular cells of the thyroid gland (thyrocytes) leading to the condition of either hyperthyroidism or hypothyroidism. The inflammation in AITDs consistently associate with ER function due to which disturbances in the ER protein homeostasis leads to unfolded protein response (UPR) that promotes pathogenesis of autoimmunity. The roles of ER stress in the instantaneous downregulation of MHC class I molecules on thyrocytes and the relevance of IFN γ in the pathogenesis of AITD has been well-documented. Thyroglobulin being the major target of autoantibodies in most of the AITDs is because of its unusual processing in the ER. Autoimmune disorders display a conglomeration of ER stress-induced UPR activated molecules. Several epidemiological data highlight the preponderance of AITDs in women as well as its concurrence with breast cancer. Both being an active glandular system displaying endocrine activity, thyroid as well as breast tissue show various commonalities in the expression pattern of heterogenous molecules that not only participate in the normal functioning but at the same time share the blame during disease establishment. Studies on the development and progression of breast carcinoma display a deranged and uncontrolled immune response, which is meticulously exploited during tumor metastasis. The molecular crosstalks between AITDs and breast tumor microenvironment rely on active participation of immune cells. The induction of ER stress by Tunicamycin advocates to provide a model for cancer therapy by intervening glycosylation. Therefore, this review attempts to showcase the molecules that are involved in feeding up the relationship between breast carcinoma and AITDs.

Transformed epithelial cells and fibroblasts/myofibroblasts interaction in breast tumor: a mathematical model and experiments

It is well known that tumor and its microenvironment, or stroma, interact with each other and that this interaction plays a critical role in tumor initiation, growth, and metastasis. This interaction consists of complex relations between tumor cells, stromal cells such as fibroblasts, epithelial cells and immunocytes, the vascular system, the extracellular matrix, and cytokines secreted by the cells. Understanding these relationships may lead to new therapeutic approaches to cancer. In the present paper, we consider tumor-stroma crosstalk in a simple in vitro situation which involves interaction between tumor epithelial cells from breast cancer and a microenvironment consisting of just fibroblasts. The two populations of cells are separated by a semi-permeable membrane that allows only cytokines to cross over. We develop a mathematical model that includes two critical growth factors: TGF-beta, produced by the tumor cells, and EGF, secreted by the fibroblasts. The TGF-beta modifies the microenvironment by transforming fibroblasts into myofibroblasts. Myofibroblasts secrete higher concentrations of EGF than fibroblasts, thereby, increasing the proliferation of tumor cells. Thus already in this simple setup one sees a mutual interaction between tumor cells and their microenvironment. We conducted experiments which show good agreement with the model's simulations, hence confirming the model's ability to predict aspects of tumor cell behavior in response to signaling from fibroblasts.

Secretion of Cytokines in Breast Cancer Cells: The Molecular Mechanism of Procathepsin D Proliferative Effects

Procathepsin D (pCD) is a major secreted protein in estrogen receptor-positive (ER+) breast cancer cell lines. Several independent studies have documented pronounced mitogenic effect of secreted pCD on cancer tissue-derived cell lines, including those from breast, lung, and prostate cancer. It has also been shown that the proliferative effect of pCD involves both autocrine and paracrine modes of action. Recent studies have suggested that pCD could act as a key paracrine communicator between cancer and stromal cells. We have shown earlier that the proliferative activity of pCD depends on the activation peptide sequence of pCD. The present study casts light on the mechanism by which pCD influences the proliferation of cancer cells expressing the ER. Results described in the current paper clearly show that pCD initiates secretion of cytokines interleukin-4 (IL-4), IL-8, IL-10, IL-13, macrophage inflammatory protein-1beta and (MIP-1beta) from such tumor cells. Secreted cytokines take part in the proliferation of the cancer cells, as proven by selective inhibition using antibodies. In addition, expression of cytokine receptors on tested cell lines corresponded to the effects of individual cytokines. An analogous pattern was also observed for fibroblasts, which, under physiologic conditions, are the cells in closest contact with the tumor tissue and play a role in tumor growth and invasion. Our observations were further supported by coculture experiments that are in agreement. Although very similar in response to addition of pCD, the invasive ER- cells do not secrete cytokines. Together with previous in vivo results, these data point to pCD as one of key molecules for therapeutic attack in breast cancer.

Association between breast cancer and autoimmune thyroid disorders: no increase of lymphocytic infiltrates in breast malignant tissues

An association between thyroid autoimmunity and breast cancer (BC) has been consistently reported, but the cause of this association is still unknown. The role of lymphocytic infiltration (LI) in breast tumorigenesis is controversial and several data suggest that in BC an increase of lymphoid cell infiltrates or a dysfunctional local immune response may be detected very early during tumor development. Chronic autoimmune thyroiditis is characterized by different degrees of LI in thyroid gland and BC cells share some antigenic properties similar to those detected in thyroid tissue, such as sodium iodide symporter (NIS) and peroxidase activity. The aim of this study was to evaluate the frequency and amount of LI in malignant and in normal peritumoral breast tissues, as expression of autoimmune morphological changes, in a group of BC patients with thyroid autoimmunity. We suppose that an increased LI in breast tissues of this group of patients may help explain the association between BC and thyroid autoimmunity. The study group included 26 BC patients with thyroperoxidase antibodies positivity (TPOAb+), 14 of them (53.8%) with Hashimoto's thyroiditis (HT), and 30 BC patients with no evidence of thyroid autoimmune disorders. Malignant and surrounding normal breast tissues were assessed for LI. The amount of LI was scored as very scanty or scanty (LI S) and moderate or marked (LI M), independently by two expert pathologists. LI S was detected in 19/26 (73.1%) BC tissues from patients with TPOAb positivity and LI M in 7 (26.9%). All BC patients with HT had LI S. LI S was detected in 25/30 (83%) and LI M in 5/30 (17%) of BC tissue from patients with no thyroid autoimmunity. The difference in the amount of LI of BC tissues in patient with or without autoimmune thyroid disorders was not significant. The LI was generally absent or very scanty in remote breast tissue in all cases. In conclusion, in breast malignancies the presence of humoral and/or clinical evidence of thyroid autoimmunity is not associated to autoimmune morphological changes of cancer and peritumoral normal tissue. The LI does not seem to have any role in tumorigenesis in patients with BC and thyroid autoimmunity.

Clonogenic growth of human breast cancer cells co-cultured in direct contact with serum-activated fibroblasts

Introduction

Accumulating evidence suggests that fibroblasts play a pivotal role in promoting the growth of breast cancer cells. The objective of the present study was to characterize and validate an in vitro model of the interaction between small numbers of human breast cancer cells and human fibroblasts.

Methods

We measured the clonogenic growth of small numbers of human breast cancer cells co-cultured in direct contact with serum-activated, normal human fibroblasts. Using DNA microarrays, we also characterized the gene expression profile of the serum-activated fibroblasts. In order to validate the in vivo relevance of our experiments, we then analyzed clinical samples of metastatic breast cancer for the presence of myofibroblasts expressing α-smooth muscle actin.

Results

Clonogenic growth of human breast cancer cells obtained directly from in situ and invasive tumors was dramatically and consistently enhanced when the tumor cells were co-cultured in direct contact with serum-activated fibroblasts. This effect was abolished when the cells were co-cultured in transwells separated by permeable inserts. The fibroblasts in our experimental model exhibited a gene expression signature characteristic of 'serum response' (i.e. myofibroblasts). Immunostaining of human samples of metastatic breast cancer tissue confirmed that myofibroblasts are in direct contact with breast cancer cells.

Conclusion

Serum-activated fibroblasts promote the clonogenic growth of human breast cancer cells in vitro through a mechanism that involves direct physical contact between the cells. This model shares many important molecular and phenotypic similarities with the fibroblasts that are naturally found in breast cancers.

A visual-quantitative analysis of fibroblastic stromagenesis in breast cancer progression

One fundamental difference between normal and transformed cells is the way they interact with their immediate environment. Exploring this difference is crucial for understanding the pathobiology of cancer progression. Benign epithelial tumors are constrained by a surrounding stroma consisting, among other cells, of fibroblasts embedded within fibrillar three-dimensional matrices. However, at a critical point in tumor progression, tumor cells become altered and overcome the barrier, inducing changes in the stroma, which promote, rather than impede, tumor progression. Inherited or acquired genetic aberrations affecting mammary gland epithelia are usually blamed for promoting neoplasia in individuals at "high risk" for breast cancer. However, in addition to these epithelial aberrations certain individuals possess permissive breast stroma. The occurrence of this permissive stroma results in a predisposition for cancer initiation or progression. Here we review stromagenic stages, experimental 3D systems, and discuss digital imaging analyses suitable for uncovering the mechanisms behind fibroblastic breast stromagenesis.

Altered expression of HLA class I antigens in breast cancer: association with prognosis

Loss of surface expression of class I major histocompatibility antigens is commonly observed in malignant tumors and has been considered one of the mechanisms for escape from cytotoxic T cells. However, natural killer cells kill cells lacking HLA class I antigens. In the present study, we characterized by immunohistochemistry the HLA class I expression of breast carcinomas from 187 patients with TNM stages I and II, diagnosed 1981-1984, using beta(2)-microglobulin as a marker and evaluated the effect on survival with a follow-up of up to 14 years. The largest group (48%) consisted of HLA class I-negative tumors (< or =10% of cells stained), mixed expression (>10% and <80% of cells stained) was seen in 36% and only 15% were classified as HLA class I-positive (> or=80% cells stained). No associations could be established with various clinicopathological parameters, such as tumor size, presence of lymph node metastases, histological grade, expression of hormone receptors, S phase and p53 mutations. There was no effect on recurrence-free survival in the whole group; but among node-negative patients (n = 86), those who had tumors with mixed HLA class I expression had a significantly higher probability of disease recurrence (OR = 3.42, p = 0.014) than patients with either HLA class I-positive or -negative tumors, particularly after more than 5 years. In node-positive patients who received adjuvant therapy, this phenotype was not associated with disease recurrence.

Short-term primary culture of epithelial cells derived from human breast tumours

As experimental models for breast cancer, most studies rely on established human breast cancer cell lines. However, many of these lines were established over 20 years ago, many from pleural effusions rather than the primary tumour, so the validity of using them as representative models is questionable. This paper describes our experiences, over a 3-year period, in establishing short-term epithelial-cell-enriched preparations from primary breast tumours based on differential centrifugation followed by culture in selective media. Epithelial cells were successfully cultured from 55% of samples, but culture success did not appear to be correlated with tumour histology, stage, grade or node status. Epithelial cell-enriched cultures were immunopositive for broad-spectrum cytokeratin and epithelial membrane antigen (EMA). Positivity for keratin 19 confirmed that the cultures contained tumour-derived cells, which additionally showed significantly higher activity of the reductive pathway of the steroid-converting enzyme 17beta-hydroxysteroid dehydrogenase type I. That the cultures contained tumour and not normal epithelial cells was further substantiated by the complete absence of the calmodulin-like gene NB-1 in tumour-derived cultures; this is only associated with normal breast epithelia. Eighty-five per cent of cultures established from oestrogen receptor (ER)-positive tumours expressed ER in vitro; this was functional in 66% of cultures, although ER-positive phenotype was gradually lost over time. In conclusion, epithelial cells can be isolated and maintained as short-term cultures from primary breast tumours irrespective of histopathological or clinical details, providing a model system with a greater biological and clinical relevance than breast cancer cell lines.

Squamous cell Carcinomas of the Head and Neck Cultured in Floating Collagen Gels: 1. The Maintenance of Stromal and Epithelial Elements in Vitro without Fibroblast Overgrowth

The study of the molecular biology of head and neck squamous cell carcinomas has been heavily reliant on the analysis of cell lines. This is largely because the maintenance of primary cell cultures is difficult. However, being monoclonal, cell lines are not representative of the primary tumor because of the loss of tumor cell heterogeneity. We report a technique for primary culture of squamous cell carcinomas with maintenance of epithelial and stromal cell components without overgrowth of the fibroblast cells. Phenotypic markers for fibroblasts and squamous cells were present up to 45 days after initiation of culture, and expression of epidermal growth factor receptor and involucrin in cultures paralleled that in the primary tumor. In vivo, tumor stromal elements are thought to play an important role in the support of epithelial cell growth. In the collagen gel system the preservation of the stromal cell component likely improves culture viability and growth. More importantly, this culture system allows the in vitro tumor to more accurately reflect the tumor from which it was derived, and it permits the study of primary squamous cell carcinomas under in vitro conditions.

Cytogenetic studies of breast carcinomas: different karyotypic profiles detected by direct harvesting and short-term culture

Chromosome analysis was performed on samples from 85 consecutive patients with breast cancer by one or more of three different methods: direct harvest, culture after mechanical disaggregation, and culture after collagenase digestion. Metaphases suitable for karyotyping were obtained in 70% of the cases; direct harvest yielded metaphases in 29% and cultures without and with digestion in 40% and 59%, respectively. Chromosomal abnormalities were detected in 37 cases. Cells judged to be phenotypically abnormal in culture were twice as likely to reveal chromosomal aberrations as normal-looking cells. Eight cases showed multiclonal abnormalities. Significant differences were detected in the karyotypic profile depending on the method used. With direct harvest, the yield of complex chromosomal changes was 87%, compared to 44% after culture of digested tissue (P < 0.01), and also polyploidy was more common in direct-harvested samples. Detailed karyotypic analysis was possible in 29 primary tumors. The chromosomes most frequently involved were 1, 3, 7, 11, 16, and 17. Recurrent structural abnormalities were der(1;16)(q10;p10), i(1)(q10), del(6)(q21), and del(1)(p22). Breakpoints clustered to the centromere regions of chromosomes 1, 3, 11, 15, and 16 and to the short arms of chromosomes 7, 17, and 19. Seven of twenty-nine fully analyzed cases had a family history of breast cancer, and changes of chromosomes 1, 3, and 15 seemed to be more common in these cases. There was an association between karyotype and survival: The 3 year survival was 63% in patients with complex karyotypic changes and 92% in those without complex changes.

Interactions between the immune system and breast cancer

The functional and prognostic significance of lymphocytic infiltration of breast carcinomas has remained unclear. Using primary cultures we have demonstrated that lymphocytes could stimulate the growth of breast cancer epithelium in about half of the cases tested. The growth stimulation was subsequently shown to be strongly correlated with expression of MHC class I by the tumour cells. Furthermore, preliminary data suggest that carcinomas with a mixed population of MHC class I-positive and -negative cells were associated with a higher incidence of lymph node metastases and increased relapse rate compared with tumours that were homogeneously MHC class I-positive or -negative. The interactions between breast cancer and the immune system are clearly complex and the results suggest that the nature of these interactions can be some extent be determined by the level and pattern of MHC class I expression by the tumour cells.

TP53 abnormalities and genetic instability in breast cancer

TP53 abnormalities in breast carcinomas and inherited TP53 changes in breast cancer patients and in Li-Fraumeni-like families were looked for. Tumours were screened for mutations in the TP53 gene by means of the PCR-CDGE method followed by PCR and direct sequencing. Allelic loss was determined by polymorphic markers, by comparing normal and tumour DNA. Abnormal protein expression was examined by immunohistochemical staining. TP53 abnormalities in the tumours were examined in relation to genetic instability, clinical data and family history. Genetic instability was studied by detection of oncogene amplification, allelic loss, karyotype analysis and fluorescent in situ hybridization, FISH. Our studies showed that TP53 abnormalities were significantly associated with amplification of the erbB2 oncogene and allelic loss on chromosome 17. Chromosomal abnormalities were also significantly more common in tumours with TP53 abnormalities. Looking at clinical data we found significant association between TP53 abnormalities and poor prognosis.