The interaction of the potato-derived chymotrypsin inhibitor with C3H/10T1/2 cells

Billings, Paul C.; Jin, Tina; Ohnishi, Noriko; Liao, David C.; Habres, Joan M.

doi:10.1093/carcin/12.4.653

Cited by 8 publications

(4 citation statements)

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“…The specificity of the effect of proteasome inhibition was tested by the use of alternative protease inhibitors. Since some of these inhibitors have low cell permeability (Suzuki et al, 1981; Billings et al, 1991; Ishisaka et al, 1998; Taylor et al, 2004), high concentrations were applied in the culture medium of RPE cells for up to 16 h. E64 (10 μM), Leupeptin (50 μM), Pepstatin A (1 μM), Soybean Trypsin inhibitor (100 μM), and Chymotrypsin inhibitor (100 μM) were used. None caused mitotic arrest or the emergence of mitotic cells with multiple MTOCs.…”

Section: Resultsmentioning

confidence: 99%

Spindle pole fragmentation due to proteasome inhibition

Ehrhardt

Sluder

2005

Journal Cellular Physiology

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During interphase, the centrosome concentrates cell stress response molecules, including chaperones and proteasomes, into a proteolytic center. However, whether the centrosome functions as proteolytic center during mitosis is not known. In this study, cultured mammalian cells were treated with the proteasome inhibitor MG 132 and spindle morphology in mitotic cells was characterized in order to address this issue. Proteasome inhibition during mitosis leads to the formation of additional asters that cause the assembly of multipolar spindles. The cause of this phenomenon was investigated by inhibiting microtubule-based transport and protein synthesis. These experimental conditions prevented the formation of supernumerary asters during mitosis. In addition, the expression of dsRed without proteasome inhibition led to the fragmentation of spindle poles. These experiments showed that the formation of extra asters depends on intact microtubule-based transport and protein synthesis. These results suggest that formation of supernumerary asters is due to excessive accumulation of proteins at the spindle poles and consequently fragmentation of the centrosome. Together, this leads to the conclusion that the centrosome functions as proteolytic center during mitosis and proteolytic activity at the spindle poles is necessary for maintaining spindle pole integrity.

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Section: Resultsmentioning

confidence: 99%

Spindle pole fragmentation due to proteasome inhibition

Ehrhardt

Sluder

2005

Journal Cellular Physiology

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Section: Introductionmentioning

confidence: 85%

“…The BBI has also been shown to suppress radiation-induced transformation of C3H/1OT/2 mouse embryo fibroblast cells at nanomolar concentrations (21) and to inhibit the transformation of BALB/3T3 cells induced by radiation or chemical carcinogens (benzo[a]pyrene and P-propiolactone) (6). We have shown that BBI as well as other anticarcinogenic protease inhibitors are internalized by C3H/10T1/2 cells (7,28,29).A major focus of our research is to elucidate the mechanism(s) by which protease inhibitors such as BBI suppress carcinogenesis. To accomplish this goal, we believe it will be necessary to identify and characterize the target enzymes that specifically interact with the BBI.…”

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confidence: 99%

A growth-regulated protease activity that is inhibited by the anticarcinogenic Bowman-Birk protease inhibitor.

Billings

Habres²

1992

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

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The Bowman-Birk protease inhibitor (BBI) has been shown to be an effective suppressor of carcinogenesis in vivo and in vitro. To elucidate the mechanism(s) by which BBI suppresses carcinogenesis, we believe it will be necessary to identify and characterize the target enzymes that specifically interact with the BBI. We have shown previously that several cellular proteins in C3H/1OT'/2 mouse embryo fibroblast cells specifically bind to a BBI affinity resin. In the current report, we demonstrate that one of these proteins has proteolytic activity as judged by its ability to degrade gelatin. The enzyme has a mass of 45 kDa and subcellular fractionation experiments demonstrate that this enzyme is located in the cytosol. Furthermore, the proteolytic activity was inhibited by diisopropylfluorophosphate but was not affected by EDTA, indicating that this enzyme is a serine protease. Higher levels of protease activity were found in logarithmic-phase C3H/1OTI/2 cells compared with nondividing (confluent) cells, suggesting that this protease activity is growth regulated. Similar levels of this activity were present in nontransformed and in radiationtransformed C3H/1OT'/2 cells. Treatment of nontransformed C3H/1OT1/2 cells with phorbol 12-myristate 13-acetate increased the specific activity of this protease 5-to 10-fold. Our results suggest that this protease is a target enzyme of the BBI in these cells.Epidemiological data suggest that nutritional factors play a major role in the etiology of cancer at many different sites (1-4). For example, high dietary levels of legumes have been associated with low cancer rates in general and are inversely correlated with the incidence of breast, colon, pancreatic, and prostate cancer (1-4). Legumes are known to contain high concentrations of protease inhibitors (5). While protease inhibitors have been shown to have strong anticarcinogenic activity in in vivo and in vitro cancer model systems (for examples, see refs. 6-21), relatively little is known about the precise mechanism(s) by which these compounds exert their suppressive effects. We have hypothesized that protease inhibitors block carcinogenesis by inhibiting cellular enzymes involved in induction and/or expression of the transformed phenotype (22-24).The anticarcinogenic activity of the soybean-derived Bowman-Birk protease inhibitor (BBI) has been extensively studied in our laboratory (6,8,13,17,(19)(20)(21). The BBI is an 8-kDa protein that effectively inhibits trypsin and chymotrypsin (25) as well as several other proteases (22,(24)(25)(26)(27). BBI has been shown to suppress dimethylbenz[a]anthraceneinduced cheek pouch carcinogenesis when topically applied (15), 3-methylcholanthrene-induced lung tumorigenesis when injected (20), and dimethylhydrazine-induced colon and liver carcinogenesis in mice when present in the diet (8,17,19). The BBI has also been shown to suppress radiation-induced transformation of C3H/1OT/2 mouse embryo fibroblast cells at nanomolar concentrations (21) and to inhibit the transformation of BAL...

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“…1) quelled the X-ray-induced transformation of mouse embryo fibroblast cells (Yavelow et al, 1985). Potato protease inhibitors (PPI) I and II showed similar in vitro effects (Billings et al, 1991). Potato carboxypeptidase inhibitor suppressed growth of several human adenocarcinoma cell lines, most probably due to its antagonistic effect on epidermal growth factor expression (Blanco-Aparicio et al, 1998).…”

Section: Cancermentioning

confidence: 99%

Protease inhibitors and their peptidomimetic derivatives as potential drugs

Fear

Komarnytsky

Raskin

2007

Pharmacology & Therapeutics

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Precise spatial and temporal regulation of proteolytic activity is essential to human physiology. Modulation of protease activity with synthetic peptidomimetic inhibitors has proven to be clinically useful for treating human immunodeficiency virus (HIV) and hypertension and shows potential for medicinal application in cancer, obesity, cardiovascular, inflammatory, neurodegenerative diseases, and various infectious and parasitic diseases. Exploration of natural inhibitors and synthesis of peptidomimetic molecules has provided many promising compounds performing successfully in animal studies. Several protease inhibitors are undergoing further evaluation in human clinical trials. New research strategies are now focusing on the need for improved comprehension of protease-regulated cascades, along with precise selection of targets and improved inhibitor specificity. It remains to be seen which second generation agents will evolve into approved drugs or complementary therapies.

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The interaction of the potato-derived chymotrypsin inhibitor with C3H/10T1/2 cells

Cited by 8 publications

References 0 publications

Spindle pole fragmentation due to proteasome inhibition

Spindle pole fragmentation due to proteasome inhibition

A growth-regulated protease activity that is inhibited by the anticarcinogenic Bowman-Birk protease inhibitor.

Protease inhibitors and their peptidomimetic derivatives as potential drugs

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