Chemopreventive Agents

Proteins secreted (the secretome) from cancer cells are potentially useful as biomarkers of the disease. Using LC-MS/MS, the secreted proteomes from a series of isogenic breast cancer cell lines varying in aggressiveness were analyzed by mass spectrometry: non-tumorigenic MCF10A, premalignant/ tumorigenic MCF10AT, tumorigenic/locally invasive MCF10 DCIS.com and tumorigenic/ metastatic MCF 10CA cl. D. Proteomes were obtained from conditioned serum-free media, partially fractionated using a small reverse phase C2 column and digested with trypsin for analysis by LC-MS/MS, using a method previously shown to give highly enriched secreted proteomes (Mbeunkui, et. al., J. Prot. Res. 5, 899-906 2006). The search files produced from 5 analyses (3 separate preparations) were combined for database searching (Mascot) which produced a list of over 250 proteins from each cell line. The aim was to discover highly secreted proteins which changed significantly in abundance corresponding with aggressiveness. The most apparent changes were observed for alpha-1-antichymotrypsin and galectin-3-binding protein which were highly secreted proteins from MCF10 DCIS.com and MCF10CA cl. D, yet undetected in the MCF10A and MCF10AT cell lines. Other proteins showing increasing abundance in the more aggressive cell lines included alpha-1-antitrypsin, cathepsin D and lysyl oxidase. The S100 proteins, often associated with metastasis, showed variable changes in abundance. While the cytosolic proteins were low (e.g. actin and tubulin), there was significant secretion of proteins often associated with the cytoplasm. These proteins were all predicted as products of non-classical secretion (SecretomeIP, Center for Biological Sequence Analysis). The LC-MS/MS results were verified for five selected proteins by western blot analysis, and the relevance of other significant proteins is discussed. Comparisons with two other aggressive breast cancer cell lines are included and the protein with consistent association with aggressiveness in all lines, and in unrelated cancer cells, was the galectin-3-binding protein which has been associated with breast, prostate and colon cancer earlier, supporting the approach and findings. This analysis of an isogenic series of cell lines suggests the potential usefulness of the secretome for identifying prospective markers for the early detection and aggressiveness/progression of cancer.

show abstract

“…Somewhat contrasting to these reports are the clinical use of chymotryptic protease inhibitors (e.g. AACT) as cancer suppressing agents [33].…”

Section: Validation Of the Lc-ms Datamentioning

confidence: 96%

Identification of Differentially Secreted Biomarkers Using LC-MS/MS in Isogenic Cell Lines Representing a Progression of Breast Cancer

et al. 2007

View full text Add to dashboard Cite

show abstract

“…Inh I and Inh II are effective proteinase inhibitors of chymotrypsin and trypsin (3,4) and have been reported to display anticarcinogenic properties by suppressing irradiation-induced transformation of mouse embryo fibroblasts (6). Although the mechanisms underlying these effects are poorly understood, the inhibition of chymotrypsin-like enzymes is believed to play an important role in the reported anticarcinogenic effect (30). We have previously demonstrated that blocking AP-1 activity inhibits tumor transformation, suggesting that AP-1 activity is necessary for tumor promoter-induced transformation (10).…”

Section: Resultsmentioning

confidence: 99%

Proteinase inhibitors I and II from potatoes block UVB-induced AP-1 activity by regulating the AP-1 protein compositional patterns in JB6 cells

Chen

Kaji

Bode

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

P lants typically respond to environmental stress such as insect herbivory, mechanical damage, and ultraviolet (UV) irradiation by inducing defense-related proteins (1, 2). Among these proteins, proteinase inhibitors I (Inh I) and II (Inh II) isolated from potato leaves are two well-characterized chymotrypsin inhibitors. Both proteins accumulate in potato and tomato leaves and are involved in signal transduction pathways in the plant's protective response against environmental herbivores and pathogens (3-5). In addition, these inhibitors have also been reported to have an inhibitory effect on irradiation-induced cell transformation in mammalian cells (6). We reported previously that both Inh I and Inh II block UVB-or UVC-induced transcription activator protein 1 (AP-1) activity in mouse JB6 cells (7). Considering the critical role that AP-1 activation plays in malignant cellular transformation and tumorigenesis (8-15), the inhibitory effects of these compounds on AP-1 activation may explain their reported antitumor effects. The precise mechanism explaining the inhibition is, however, unclear.AP-1 is an inducible eukaryotic transcription factor composed of products of the jun and fos oncogene families that form Jun-Jun or Jun-Fos dimers (16,17). When stimulated, AP-1 binds to specific transactivation promoter regions or TREs (12-O-tetradecanoylphorbol 13-acetate response elements) on DNA to induce transcription of genes involved in cell proliferation, metastasis, and metabolism (18). Many positive and negative components are involved in the regulation of AP-1 activity. Among these regulators, mitogen-activated protein kinase (MAP kinase) signaling pathways are common mediators of AP-1 function (19). However, we have previously observed that both Inh I and Inh II fail to block extracellular signalregulated kinases (ERKs), c-Jun N-terminal kinases (JNKs), or p38 kinase, three members of the MAP kinase family (7). This observation suggested that inhibition of AP-1 activity by Inh I and Inh II is mediated by a mechanism independent of the MAP kinase pathways.Nuclear factor B (NF B) is another eukaryotic transcriptional factor that appears to be critically involved in regulating the expression of a variety of genes that participate in the inflammatory response and suppression of apoptosis, as well as cell proliferation (20,21). Furthermore, subunits of AP-1 and NF B are able to ''cross-talk,'' and thus both transcription factors may play a role in cellular transformation (22,23). Recent reports have indicated that both AP-1 and NF B are involved in tumor promoter-induced progression in the human keratinocyte transformation model (24,25).To elucidate how the proteinase inhibitors suppress AP-1 activity and whether NF B is involved in this mechanism, we investigated changes in both AP-1 and NF B activities and DNA-binding capacities in response to cellular treatment with Inh I and Inh II and exposure to UVB, respectively. We also determined changes in the AP-1 protein composition after treatment with the Inh I and Inh I...

show abstract

“…Among its more prominent properties is that this protein remains intact after oral ingestion, inhibits a wide range of proteases, and has a chymotrypsin active site. The unique properties of this agent and the extensive activity of BowmanBirk inhibitor in in vitro assays and in animal models are summarized in several reviews (29,30); most relevant to this current discussion was the demonstration of activity in the hamster oral cheek pouch model in 1986 (31), and in 1992, the demonstration of mucosal proteases in exfoliated oral keratinocytes in humans (32). These data provided the basis for development of Bowman-Birk inhibitor as a drug, which was a formidable task.…”

Section: The Summer Years: Difluoromethylornithine and Bowman-birk Inmentioning

confidence: 99%

American Society of Preventive Oncology Distinguished Career Achievement Lecture 2006—Enjoy the Journey: The Long and Winding Road of Chemoprevention Agent Development

Meyskens

2006

Cancer Epidemiology, Biomarkers &Amp; Prevention

View full text Add to dashboard Cite

Chemopreventive Agents

Cited by 289 publications

References 242 publications

Identification of Differentially Secreted Biomarkers Using LC-MS/MS in Isogenic Cell Lines Representing a Progression of Breast Cancer

Identification of Differentially Secreted Biomarkers Using LC-MS/MS in Isogenic Cell Lines Representing a Progression of Breast Cancer

Proteinase inhibitors I and II from potatoes block UVB-induced AP-1 activity by regulating the AP-1 protein compositional patterns in JB6 cells

American Society of Preventive Oncology Distinguished Career Achievement Lecture 2006—Enjoy the Journey: The Long and Winding Road of Chemoprevention Agent Development

Contact Info

Product

Resources

About