Epithelial to Mesenchymal Transition in Human Breast Cancer Can Provide a Nonmalignant Stroma

Abstract

A breast carcinoma biopsy showed cytochemical evidence of epithelial mesenchymal transition and an ␣-smooth muscle actin-positive stromal reaction. To study the lineage, and the nature of the cells in the stromal reaction, we derived a novel cell line, HBFL-1, from the explanted biopsy. HBFL-1 cells are immortal and exhibit a shared non-random X-chromosome inactivation pattern with the epithelial tumor of origin. Yet they closely resemble normal, finite-life-span fibroblasts by morphology, lack of tumor formation in nude mice, marker expression profile, protein pattern using two-dimensional gel electrophoresis and the ability to undergo myofibroblast conversion. HBFL-1 interacts reciprocally with tumor cells in collagen gel to induce activation of MMP2, leading to tumor-like behavior of epithelial colonies. In vivo, HBFL-1 cells resembled normal-derived myofibroblasts and conferred a significant 3.5-to 7-fold increase in MCF-7 tumor size in nude mice. However, that they were indeed not normal fibroblasts was revealed by residual keratin expression and formation of epithelial microfoci in a reconstituted basement membrane and in nude mice. We conclude that breast cancer can generate its own nonmalignant stroma and that one function for this is that of a reciprocal interac- Epithelial mesenchymal transition (EMT) was originally described as a normal developmental process. 1,2 Later, it was adopted as an explanation for mesenchymal conversion in a number of cultured epithelial cells. 3,4 In cancer, EMT generally depicts a more aggressive behavior of the tumor cells. 5,6 In breast cancer, EMT has been estimated to occur in as much as 18% of tumors in vivo. [7][8][9] Under these conditions EMT is defined as the occurrence of a variable proportion of tumor cells that express mesenchymal markers such as vimentin, tenascin and stromelysin-3. 7,10 In its most elaborate form, EMT-derived cells of mixed epithelial-mesenchymal breast tumors may be difficult to distinguish from resident normal stromal cells. 11 These tumors which are also referred to as carcinosarcomas or metaplastic carcinomas in particular offer an excellent opportunity to study the nature and the consequence of this subset of EMT. 5,6 Such studies, however, have been hampered by lack of representative cell lines most likely due to low frequency of overtly metaplastic carcinomas but also to difficulties in culturing breast cancer cells in general. In the present study we succeeded in isolating a mesenchymal-like cell line from a metaplastic human breast carcinoma. Clonality analysis revealed that the cell line and the epithelial tumor cells of origin had a common ancestor. Even though the cells were immortal and severely aneuploid, and exhibited a rudimentary epithelial phenotype in terms of keratin expression and formation of microfoci in Matrigel and in vivo, they nevertheless behaved remarkably like normal resident fibroblasts. In particular they responded to transforming growth factor-␤ (TGF-␤) by having ␣-smooth muscle actin (␣-sm actin) induced and t...

Preliminary screening and identification of stem cell-like sphere clones in a gallbladder cancer cell line GBC-SD

“…Tumor fibroblasts play an important role in tumor development. Previous studies have been based on the hypothesis that tumor fibroblasts were recruited from the surrounding microvessels to the malignant tissues (Petersen et al, 2003;Puré, 2009). In serumcontaining medium, sphere clones exhibited fibroblast morphology after adherence, and the cells could be labeled by the fibroblast marker vimentin (Fig.…”

Periostin, secreted from stromal cells, has biphasic effect on cell migration and correlates with the epithelial to mesenchymal transition of human pancreatic cancer cells

“…This process, referred to as ''epithelial to mesenchymal transition (EMT),'' intensifies the motility and invasiveness of many cell types and is often considered a prerequisite for tumor infiltration and metastasis. 3,4 Pancreatic cancer is the fourth leading cause of cancer-related deaths in the industrialized world. 21 Once pancreatic cancer is clinically evident, it rapidly develops metastatic lesions, frequently by the time of diagnosis.…”

“…This transition is considered to be an important event during malignant tumor progression and metastasis. [3][4][5] Periostin is a secretory protein that has been suggested to function as a cell adhesion molecule for preosteoblasts and to participate in osteoblast recruitment, attachment and spreading. 6,7 Recently, the expression of periostin has been implicated in the development of variety of carcinomas such as neuroblastoma, 8 epithelial ovarian cancer 9 and non-small cell lung carcinoma.…”

Pancreatic Cancer Stem Cells

“…Unfortunately, there is an increasingly accepted consensus suggesting that the inappropriate activation of the EMT processes contributes in part to the increased invasive and metastatic potential of various tumors [67][68][69][70][71][72][73][74]. There are also evidences exist associating the EMT process with the origin of CSCs and considering EMT as a precondition for cancer metastasis.…”

“…There are also evidences exist associating the EMT process with the origin of CSCs and considering EMT as a precondition for cancer metastasis. Based on this, many researchers are striving to develop EMT as a target for cancer treatment [49,51,69,70]. resveratrol on human lung cancer, Wang H et al [75] found that resveratrol (trans-3,4,5 trihydroxy stilbene, found in several plants) was effective to increase the expression of epithelial phenotype marker E-cadherin and to downregulate the mesenchymal marker Fibronectin and Vimentin, which led them to conclude that the resveratrol could be used as an inhibitor of TGF-β1-induced EMT, in that it triggered the process of MET reversal in in virto conditions with A549 lung cancer cells whose invasiveness and metastasis were largely reduced [75].…”