Modulation of markers associated with aggressive phenotype in MDA-MB-231 breast carcinoma cells by sulforaphane.

Metastasis as a complex process involves loss of adhesion, migration, invasion and proliferation of cancer cells. Sulforaphane (SFN) is one of naturally occurring cancer chemopreventive isothiocyanates found in cruciferous vegetables, consumption of which has been associated with reduced risk of cancer. In this study, we describe effect of SFN on various aspects determining invasive behavior of MDA-MB-231 human breast carcinoma cells. We studied modulation of molecules associated with epithelial to mesenchymal transition (EMT), hypoxic marker CA IX and mitochondrially located peripheral benzodiazepine receptor (PBR) using flow cytometry, gene expression of matrix metalloproteinases MMP1, 3, 7, 9, 14, transcription factors POU5F1 and Twist1 mRNA by RT PCR, and cytokine production by multiplex bead assay. SFN downregulated PBR and vimentin expression in a dose dependent manner, but significantly affected neither HIF-1alpha, nor CA IX protein expression, nor VEGF and GLUT1 mRNA levels. Among studied MMPs, MMP7 and MMP14 mRNA were downregulated while no apparent effect on MMP1, MMP3 and MMP9 was observed. Further, we found significant down regulation of Twist1 and POU5F1, transcription factors that mediate EMT and the self-renewal of undifferentiated embryonic stem cells. SFN reduced also the production of pro-inflammatory cytokines IL-1beta, IL-6, TNF-alpha, IFN-gamma, immunomodulating cytokine IL-4 and growth factors involved in angiogenesis PDGF and VEGF. Our study shows that SFN efficacy is associated with the reversal of several biological characteristics connected with EMT or implicated in the matrix degradation and extracellular proteolysis, as well as with reduced production of pro-inflammatory cytokines and pro-angiogenic growth factors in MDA-MB-231 cells.

Ectodomain shedding of the hypoxia-induced carbonic anhydrase IX is a metalloprotease-dependent process regulated by TACE/ADAM17.

Carbonic anhydrase IX (CA IX) is a transmembrane protein whose expression is strongly induced by hypoxia in a broad spectrum of human tumours. It is a highly active enzyme functionally involved in both pH control and cell adhesion. Its presence in tumours usually indicates poor prognosis. Ectodomain of CA IX is detectable in the culture medium and body fluids of cancer patients, but the mechanism of its shedding has not been thoroughly investigated. Here, we analysed several cell lines with natural and ectopic expression of CA IX to show that its ectodomain release is sensitive to metalloprotease inhibitor batimastat (BB-94) and that hypoxia maintains the normal rate of basal shedding, thus leading to concomitant increase in cell-associated and extracellular CA IX levels. Using CHO-M2 cells defective in shedding, we demonstrated that the basal CA IX ectodomain release does not require a functional TNFalpha-converting enzyme (TACE/ADAM17), whereas the activation of CA IX shedding by both phorbol-12-myristate-13-acetate and pervanadate is TACE-dependent. Our results suggest that the cleavage of CA IX ectodomain is a regulated process that responds to physiological factors and signal transduction stimuli and may therefore contribute to adaptive changes in the protein composition of tumour cells and their microenvironment.

The novel exon 11 mutation of BRCA1 gene in a high-risk family.

Germline mutations in the BRCA1 and BRCA2 genes are required for the initiation of the development of hereditary forms of breast and ovarian cancer, which represent 10-15% of all cases. The course of the disease varies from case to case that can be due even to the possibility of multiple genetic changes including inactivation of other tumor suppressor genes--TP53 and APC genes or activation of oncogenes, especially K-ras oncogene. The combination of these changes results in an early expression of the broad variety of malignancies. The analyzed proband (II-5) comes from a high-risk family, in which various types of cancer were observed. The novel BRCA1 mutation in exon 11 (2057delCAGTGAAGAG) was detected by SSCP, HDA techniques and confirmed by automatic sequencing. The same deletion was observed in DNA sample of her first daughter (III-1), but DNA of her second one was without any mutational changes (III-2). Due to the occurrence of different types of cancer in this family, the incidental mutations in the APC; resp. TP53 tumor supressor genes and K-ras oncogene were searched as well. Any mutation was found after sequencing of SSCP interesting exons of these genes. The reasons for such strong malignant manifestation in this high risk family are discussed.

Mutation screening of the BRCA1 gene in Slovak patients.

Breast cancer is the most commonly observed malignancy in women of the western world. The family history is the strongest risk factor for the disease. Two major genes, BRCA1 and BRCA2 that are involved in the familial breast and ovarian cancer have been described. Germ-line mutations of the BRCA1 gene have been linked to 85% of all hereditary breast and ovarian cancers. We performed a mutation screening ofthe entire codingregion of the BRCA1 gene in 29 Slovak families suspected of having inherited predisposition to breast cancer. For the analysis we used a combination of a single strand conformation polymorphism (SSCP), denaturing high-performance liquid chromatography (DHPLC) and sequencing. Genetic alterations were consistently indicated by SSCP and DHPLC and consequently confirmed by DNA sequencing as previously described pathogenic mutations. The patients with inherited BRCA1 mutations will undergo genetic counseling and cancer prevention health care program.

Cell surface immunophenotype and gelatinase activity of the human breast carcinoma cell line (MCF-7/6) with functionally defective E-cadherin.

Expression of differentiation and adhesion cell surface antigens (LewisX - CD15, CD44, syndecan 1 - CD138 and basigin/EMMPRIN - CD147) were determined on the cell surface of human breast carcinoma MCF7 cells in vitro with the aid of flow cytometry and compared with that of MCF-7/6 cells, with functionally defective E-cadherin system and increased biological aggressiveness. The major cell surface alterations in MCF-7/6 cells compared with the parental MCF-7 cell line were a markedly increased CD15 (LewisX) and CD44 antigen cell surface expression on MCF-7/6 cells. There were no major differences between parental MCF-7 and MCF-7/6 cells in cell surface syndecan 1, basigin/EMMPRIN, E-cadherin and high affinity non-integrin laminin receptor expression. The constitutive cell surface gelatinase A and B activities were absent on MCF-7 and faint in MCF-7/6 cells. Both phorbol ester TPA and tumor necrosis factor TNF-alpha induced a marked up-regulation of gelatinase B only in MCF-7/6 cells. No marked differences in penetration of MCF-7 vs. MCF-7/6 cells into collagen/fibroblast matrix in vitro were observed. The increased expression of CD15 (LewisX), CD44 antigen and TNF-alpha-inducible gelatinase B on MCF-7/6 cells may represent auxiliary factors contributing to the increased biological aggressiveness of MCF-7/6 cells.

Angiogenesis inhibitor TNP-470: cytotoxic effects on human neoplastic cell lines.

Angiostatic substance TNP-470 displayed moderate cytotoxicity towards human leukemia HL-60, HL-60/ADR, HL-60/VCR and myeloma ARH77 cell lines with IC50 in the range 5-10 microM of concentrations and slightly higher IC50 for myeloma cell line U266. IC50 for ovarian CH-1, A2780 and A2780/ADR cell lines was in the range 10-15 microM with the exception of platinum-resistant SKOV3 cell line (more than 40 microM ). The IC50 values for MDA-MB-231 and MCF-7 breast carcinoma cell lines were 15 and 25 microM, respectively. In human hemopoietic neoplastic cell lines examined, TNP-470 induced the appearance of subpopulation with sub-G0 DNA content, suggesting the apoptosis-inducing potential of TNP-470 in these cells. No TNP-470-induced drug uptake modulation in drug-resistant leukemia cell line HL-60/VCR was observed. TNP-470 induced accumulation of cells in G0/G1 phase of cell cycle. There was no TNP-470-induced inhibition of MMP collagenase activity or MMP (MMP2 and MMP9) production in the human fibrosarcoma cells HT 1080 in vitro.

Cell surface phenotype and increased penetration of human multidrug-resistant ovarian carcinoma cells into in vitro collagen-fibroblasts matrix.

Human multidrug resistant ovarian carcinoma cells (A2780/ADR) exhibited increased in vitro penetration into the collagen-normal human fibroblasts matrix, increased cell surface expression of alpha 6 integrin (CD49f antigen) and slightly increased expression of alpha 2 (CD49b) integrin compared with that of parental drug-sensitive A2780 cells. Both, multidrug-resistant and parental, drug-sensitive, cell lines did not express the 67 kDa non-integrin high affinity laminin receptor on their cell surfaces. As there were no marked differences between metalloproteinase activity of both A2780 cell sublines (with similar intensity of 72 kDa and 92 kDa lysis bands in zymograms), the increased penetration of the drug-resistant subline into the collagen-fibroblast gel matrix might be associated with the increased expression of adhesion proteins (including collagen-binding alpha 2 integrin), or cell surface-associated collagenase-stimulating protein(s). This multidrug resistant ovarian carcinoma cell line might serve as an in vitro model of neoplastic cells with increased biological aggressiveness, molecular mechanisms of which require further analysis.