Rosmarinic acid influences collagen, MMPs, TIMPs, glycosylation and MUC1 in CRL-1739 gastric cancer cell line.

Rosmarinic acid (RA) is a natural phenylpropanoid with numerous pharmacological activities. Because of limited studies of the effects of RA action in gastric cancer cells we examined how 100 and 200 µM acid influences MMPs, TIMPs, collagen, MUC1 and specific sugar antigens in gastric adenocarcinoma CRL-1739 cells. We revealed inhibitory effect of RA on MMP-9 activity what was correlated with increased collagen type I expression, main ECM substrate degraded by MMPs. Tissue inhibitor of MMPs, TIMP-1 but not TIMP-2 was significantly decreased on the protein level and increased on mRNA level by RA action what can suggest TIMP-1 independent inhibitory action of an acid on MMP-9 activity. Glycosylation of gastric cancer proteins was also effected by RA. ELISA tests revealed inhibitory effect of an acid on Tn antigen in cell lysates and culture supernatant and on T antigen in cell lysates. RA inhibited also sialylated Tn antigen in protein of culture supernatant and sialyl T in cell lysates. Extracellular domain of MUC1 mucin, main carrier of Tn and T antigens was significantly inhibited by higher dose of RA. The data suggest potential usefulness of RA as a complementary agent supporting chemotherapy in cancer treatment.

Fruit and vegetable consumption among children in a socioeconomically disadvantaged neighbourhood.

PURPOSE: Fruit and vegetable (FV) consumption was examined among children aged seven to 10 years in a London, Ontario, neighbourhood. The goal was to determine areas requiring targeted programs to promote healthy lifestyles. METHODS: Data were gathered from 136 students in grades 2 to 4. Each student attended one of four elementary schools within a neighbourhood designated a priority by the City of London Child and Youth Network. The Day in the Life Questionnaire was used to collect the data. Instances of FV consumption were compared with Eating Well with Canada's Food Guide (CFG) guidelines. RESULTS: Ninety-eight percent of participants did not follow the CFG-recommended minimum guidelines; they had fewer than five instances of FV consumption daily. Eighty-seven percent had fewer than two instances of FV consumption daily. CONCLUSIONS: These data support national findings of low FV consumption among children.

Captopril-dependent inhibition of collagen biosynthesis in cultured fibroblasts.

The mechanism underlying the dermatological manifestations that accompany captopril therapy is not known. The facts that prolidase plays an important role in collagen biosynthesis and that captopril directly inhibits prolidase activity led us to evaluate its effect on collagen biosynthesis in cultured human skin fibroblasts. Confluent fibroblasts were treated with milimolar concentrations (0.2-1 mM) of captopril (CAP) for 48 h. It was found that CAP-dependent decrease in prolidase activity was accompanied by parallel decrease in collagen biosynthesis. Since insulin-like growth factor receptor (IGF-IR) is the most potent regulator of both collagen biosynthesis and prolidase activity, and prolidase is regulated by beta1 integrin signaling, the effect of CAP on IGF-IR and beta1 integrin receptor expressions was evaluated. It was found that exposure of the cells to 0.3 mM CAP contributed to a decrease in IGF-IR, alpha2beta1 integrin receptor and MAPK/ERK1/2 expressions. The data suggest that CAP-dependent decrease of collagen biosynthesis in cultured human skin fibroblasts results from inhibition of prolidase activity that may occur through inhibition of alpha2beta1 integrin and IGF-IR signaling.

Mechanism of betulinic acid inhibition of collagen biosynthesis in human endometrial adenocarcinoma cells.

Collagen as a ligand for integrin receptors plays important role in the integrin - dependent regulation of cellular metabolism. Since betulinic acid (BA) evokes anticancer activity, its effect on collagen biosynthesis was studied in cultured endometrial adenocarcinoma cells. Confluent cells were treated with different concentrations of BA for 24 hours. It was found that BA inhibit collagen biosynthesis ([3H] proline incorporation assay). The mechanism of this phenomenon was found at the level of insulin-like growth factor-I receptor (IGF-IR) and alpha2 integrin signalling (Western immunoblot analysis). The expressions of IGF-I receptor and alpha2 integrin subunit as well as integrin activated focal adhesion kinase (FAK) were decreased in the cells treated with BA. It was accompanied by a parallel decrease in the expression of Sos protein and phosphorylated MAP-kinases (ERK1, ERK2) and up - regulation of NF-kappaB. The data suggest that BA-dependent inhibition of collagen biosynthesis in cultured human endometrial adenocarcinoma cells undergoes through alpha2 integrin and IGF-IR signaling that activate NF-kappaB, potent inhibitor of collagen gene expression.

Hyaluronic acid counteracts interleukin-1-induced inhibition of collagen biosynthesis in cultured human chondrocytes.

Although, hyaluronic acid (HA) is used in the treatment of osteoarthritis for 30 years, the mechanism of its protective action on collagen metabolism disturbances in tissues during inflammation is not known. Therefore, the present study was undertaken to evaluate the mechanism of IL-1beta action (inductor of experimental inflammation) on deregulation of collagen biosynthesis in cultured human chondrocytes and the effect of HA on the process. It has been found that IL-1beta strongly induced inhibition of collagen biosynthesis, while HA counteracted the process. The mechanism of this phenomenon was found at both transcriptional and post-transcriptional level. IL-1 was found to down regulate the expression of mRNA for type II collagen and to inhibit prolidase activity, an enzyme that plays an important role in collagen biosynthesis at post-translational level. HA was shown to counteract the IL-1beta-dependent inhibition of both processes. During experimental inflammation of chondrocytes cultured in 0.1% FBS there was no differences in the expression of beta(1)-integrin independently of cell number and the presence of HA in growth medium. In chondrocytes cultured in 5% FBS, IL-1beta up-regulated the expression of beta(1)-integrin receptor while HA abolished the effect. The data suggest that HA-dependent up-regulation of collagen biosynthesis in IL-1beta-treated chondrocytes may involve stimulation of prolidase activity in serum "starved" cells and may also originate at the transcriptional level in the cells cultured in standard conditions.

Antimitotic activity of high affinity ligands for peripheral benzodiazepine receptor (PBR) in some normal and neoplastic cell lines.

PURPOSE: Overexpression of PBR has been found in several tumor types including ovarian, colon, breast adenocarcinomas, esophageal cancer. There is evidence suggesting that PBR ligands regulate cell proliferation. However, their action is probably cell-type specific. We decided to evaluate mitotic activity of PBR ligands in some normal and neoplastic cell lines. MATERIAL AND METHODS: The cells were maintained according to standard procedures. Ligand binding assay was performed in cell extract using PK-11195 or Ro-54864 and [N-methyl-3H] Ro-54864 or [N-methyl-3H] PK-11195. Cell proliferation was evaluated using 5-[3H]-thymidine assay. Western Immunoblot assay was conducted using polyclonal anti-PBR antibody. RESULTS: We have found that, macrophages evoked strong binding of both Ro-54864 and PK-11195. This phenomenon was accompanied by drastic decrease in the cell divisions. Similar effect was found only in the case of non-estrogen-dependent breast cancer cells MDA-MB 231. It suggest that PBR-ligand mediated inhibition of mitogenesis may represent a new anticancer strategy in non-estrogen-dependent breast cancer. In respect to macrophages inhibition of the cell division by both PBR ligands may have implication in modulation of inflammatory response. It has been postulated that PBR ligands may have anti-inflammatory activity in rheumatoid arthritis. The presence of peripheral benzodiazepine receptors in chondrocytes, T cells, macrophages and mesenchymal cells suggest that peripheral benzodiazepine receptor ligands may interfere with the cytokine network and thus modulate inflammatory response. CONCLUSIONS: The data suggest that PBR-ligand mediated inhibition of DNA synthesis in non-estrogen dependent breast cancer cells and in macrophages may represent a new therapeutic approach of breast anti-cancer and anti-inflammatory therapy.

Melanin potentiates kanamycin-induced inhibition of collagen biosynthesis in human skin fibroblasts.

Ototoxicity is one of the well known side effects of kanamycin. The mechanism underlying the organ specificity of the side effect is not understood. Since many pharmacologic agents are known to form complexes with melanin and melanin is an abundant constituent of the inner ear, we investigated whether kanamycin interacts with melanin and how this process affects biosynthesis of collagen in cultured human skin fibroblasts. We found that kanamycin forms complexes with melanin. The amount of kanamycin bound to melanin increases with increase of initial drug concentration. The Scatchard plot analysis of the drug binding to melanin has shown that at least two classes of independent binding sites are implicated in the kanamycin-melanin complex formation: strong binding sites with the association constant K1 - 3 x 10(5) M(-1), and the weak binding sites with K2 - 4 x 10(3) M(-1). The number of total binding sites (n1 + n2) was calculated as about 0.64 micromol kanamycin per 1 mg melanin. We found that kanamycin induced inhibition of collagen and DNA biosynthesis (IC50 - 5 microM). Melanin at 100 microg/ml produced about 25% inhibition of DNA synthesis, but it had no effect on collagen biosynthesis in cultured fibroblasts. However, the addition of melanin (100 microg/ml) to kanamycin-treated cells (5 microM) augmented the inhibitory action of kanamycin on collagen and DNA biosynthesis. We have suggested that IGF-I receptor expression, involved in cell growth and collagen metabolism, may be one of the targets for kanamycin-induced inhibition of these processes. As shown by Western immunoblot analysis melanin augmented kanamycin-induced decrease in the expression of IGF-I receptor as well MAP kinases expression: ERK1 and ERK2. The obtained results demonstrate that melanin potentiates the inhibitory effect of kanamycin on IGF-I receptor-dependent signaling pathway in cultured fibroblasts. The data suggest a potential mechanism for the organ specificity of kanamycin-induced hearing loss in patients which may result from melanin-induced augmentation of the inhibitory effects of kanamycin on collagen and DNA biosynthesis.

The effect of hyaluronic acid on interleukin-1-induced deregulation of collagen metabolism in cultured human skin fibroblasts.

Although hyaluronic acid (HA) has been used in the treatment of osteoarthritis for 30 years, the mechanism of its protective action on collagen metabolism disturbances in tissues during inflammation is not known. The present study was undertaken to evaluate the mechanism of Interleukin-1 (IL-1)-induced deregulation of collagen metabolism in cultured human skin fibroblast and the effect of HA on the process. In normal fibroblasts IL-1 strongly induced inhibition of collagen biosynthesis, while HA counteracted the process. The mechanism of this phenomenon was independent of prolidase activity, an enzyme that plays an important role in collagen biosynthesis at the post-translational level. Instead, IL-1 was found to inhibit the expression of insulin-like growth factor-I receptor (IGF-IR) and MAP kinases-ERK1 and ERK2, while HA was shown to counteract this process. Since insulin-like growth factor-I (IGF-I) is a most potent stimulator of collagen biosynthesis in fibroblasts the mechanism of IL-1-dependent inhibition of collagen biosynthesis may be related to inhibition of IGF-IR expression and signaling. The data suggest that hyaluronic acid protects collagen against IL-1-induced inhibition of biosynthesis of this protein in cultured human skin fibroblasts at the level of IGF-IR signaling.

Doxycycline-induced inhibition of prolidase activity in human skin fibroblasts and its involvement in impaired collagen biosynthesis.

Several lines of evidence suggest that doxycycline, a semi-synthetic derivative of tetracycline, may be a useful agent in the treatment of osteoarthritis. It inhibits collagen synthesis and collagenase activity in hypertrophic chondrocytes, slowing the process of collagen turnover. However, the mechanism of doxycycline-induced inhibition of these processes has not been established. We considered prolidase, an enzyme involved in collagen metabolism, as a possible target for the doxycycline-induced inhibition of collagen synthesis. Cultured human skin fibroblasts, specialized for collagen synthesis, were used as model cells. Prolidase [E.C. 3.4.13.9] is a manganese-dependent cytosolic exopeptidase that cleaves imidodipeptides containing C-terminal proline, thus providing large amounts of proline for collagen resynthesis. Enzyme activity is regulated through the beta1 integrin receptor. Therefore, we compared the effect of doxycycline on prolidase activity and expression, collagen biosynthesis, gelatinolytic activity and beta1 integrin expression in 24-h treated cultured human skin fibroblasts. We found that doxycycline induced coordinately inhibition of prolidase activity and collagen biosynthesis (IC50 at about 150 microg/ml) and gelatinolytic activity in cultured human skin fibroblasts. The inhibitory effect of doxycycline on the processes was not due to the cytotoxicity of this drug, as shown in the cell viability tetrazoline test. However, an inhibitory effect of the drug on DNA synthesis was observed (IC50 at about 100 microg/ml). The decrease in prolidase activity in fibroblasts treated with doxycycline was not accompanied by any differences in the amount of prolidase or beta1 integrin recovered from these cells, as shown by Western immunoblot analysis. This suggests that the doxycycline-induced down-regulation of prolidase is a post-translational event. The data presented here raise the possibility that the doxycycline-induced decrease in collagen biosynthesis is mostly due to the inhibition of prolidase activity.

The potential mechanism for glutamine-induced collagen biosynthesis in cultured human skin fibroblasts.

Although glutamine (Gln) is known as an important stimulator of collagen biosynthesis in collagen-producing cells, the mechanism and endpoints by which it regulate the process remain largely unknown. Intermediates of Gln interconversion: glutamate (Glu) and pyrroline-5-carboxylate (P5C) stimulate collagen biosynthesis in cultured cells but evoke different maxima of collagen biosynthesis stimulating activity at different times of incubation. P5C was found to be the most potent stimulator of collagen biosynthesis after 6 h of incubation (approx. three-fold increase); after 12 h, it induced increase in collagen biosynthesis to 260%, while at 24 h, the process was decreased to approximately 80% of control values. Glu induced increase in collagen biosynthesis to approximately 180%, 400% and 120% of control values, after 6, 12 and 24 h, respectively, suggesting that after 12 h of incubation, Glu was the most potent stimulator of collagen biosynthesis. Glu was also the most potent stimulator of type I procollagen expression at this time. After 6, 12 and 24 h incubation, Gln induced collagen biosynthesis to approximately 112, 115 and 230% of control values, respectively. Since prolidase is known to be involved in collagen metabolism, the enzyme activity assay was performed in fibroblasts cultured in the presence of Gln, Glu and P5C. While Gln and Glu required 24 h for maximal stimulation of prolidase activity, P5C induced it after 6-12 h. The data suggest that P5C induced collagen biosynthesis and prolidase activity in a shorter time than Gln and Glu. We considered that P5C directly stimulates the processes, while Gln acts through its intermediate-P5C. Reduction of P5C to proline is coupled to the conversion of glucose-6-phosphate (G6P) to 6-phospho-gluconate, catalyzed by G6P dehydrogenase. We have found that dehydroepiandrosterone (DHEA), a potent inhibitor of G6P dehydrogenase, inhibited a stimulatory effect of P5C on collagen synthesis, expression of type I collagen and prolidase activity. Our results postulate a potential mechanism of glutamine-induced collagen biosynthesis through its intermediate - P5C. P5C-dependent activation of nucleotide biosynthesis, prolidase activity and P5C conversion into proline may contribute to the stimulation of collagen biosynthesis.

Collagen metabolism disturbances are accompanied by an increase in prolidase activity in lung carcinoma planoepitheliale.

One of the consequences of neoplastic transformation is deregulation of tissue collagen metabolism. Although metalloproteinases initiate the breakdown of collagen in lung carcinoma, the final step of collagen degradation is mediated by prolidase (E.C.3.4.13.9). We investigated whether prolidase activity could reflect disturbances of collagen metabolism in human lung carcinoma planoepitheliale (Ca pl.). Ten human lung Ca pl. and 10 samples of normal lung parenchyma were compared with respect to prolidase activity and expression (western immunoblot), the content of collagen and collagen degradation products (free and bound hydroxyproline determination), beta1 integrin subunit expression (western immunoblot) and collagenolytic activity (zymography). An increase in collagen content (66%, P < 0.05), free proline pool (50%, P < 0.05) and collagenolytic activity was accompanied by a significant increase in the prolidase activity (106%, P < 0.05) and its expression in Ca pl. No differences were found between Ca pl. and the control lung tissue with respect to beta1 integrin expression. Prolidase activity may reflect disturbances in tissue collagen metabolism in lung Ca pl. and it may, therefore, serve as a sensitive marker of the disease.

Insulin-like growth factor I-dependent regulation of prolidase activity in cultured human skin fibroblasts.

Prolidase [E.C.3.4.13.9] is a cytosolic exopeptidase that catalyses the hydrolysis of C-terminal proline containing dipeptides or tripeptides. The enzyme plays an important role in the recycling of proline for collagen synthesis. Increase in enzyme activity is correlated with increased rates of collagen turnover but the mechanism and endpoints by which this enzyme is regulated remain largely unknown. We have found that insulin-like growth factor-I (IGF-I), potent stimulator of collagen biosynthesis, induces prolidase activity in cultured human skin fibroblasts. Supporting evidence comes from the following observations: (1) Serum of fasted rats, (IGF-I, 72 +/- 16 ng/ml) showed about 50% reduced ability to stimulate prolidase activity and collagen biosynthesis in confluent fibroblasts in comparison to the effect of control rat serum (IGF-I, 168 +/- 29). (2) An addition of IGF-I (100 ng/ml) to fasted rat serum restored its ability to stimulate prolidase activity and collagen biosynthesis to control values. (3) In confluent human skin fibroblasts, cultured for 48 h with serum free medium prolidase activity was decreased to 50% of control cells, cultured in the presence of normal rat serum. Supplementation of serum free medium with EGF, PDGF and IGF-I (factors that can replace growth promoting activity of serum) stimulated prolidase activity to control values while the medium deprived IGF-I had no such effect. (4) The relative differences in prolidase activity due to specific treatment of confluent cells with above growth factors were accompanied by parallel differences in the amount of the enzyme protein recovered from these cells as shown by western immunoblot analysis. Thus we conclude that prolidase activity is regulated by IGF-I in confluent fibroblasts.

Fibroblast chemotaxis and prolidase activity modulation by insulin-like growth factor II and mannose 6-phosphate.

Chemotactic locomotion of fibroblasts requires extensive degradation of extracellular matrix components. The degradation is provided by a variety of proteases, including lysosomal enzymes. The process is regulated by cytokines. The present study shows that mannose 6-phosphate and insulin-like growth factor II (IGF-II) enhance fibroblast chemotaxis toward platelet-derived growth factor (PDGF). It is suggested that lysosomal enzymes (bearing mannose 6-phosphate molecules) are involved in chemotactic activity of the cells. The suggestion is supported by the observation that alpha-mannosidase and cathepsin D inhibitor-pepstatin are very potent inhibitors of fibroblast chemotaxis. Simultaneously, mannose 6-phosphate stimulates extracellular collagen degradation. The final step in collagen degradation is catalyzed by the cytosolic enzyme-prolidase. It has been found that mannose 6-phosphate stimulates also fibroblast prolidase activity with concomitant increase in lysosomal enzymes activity. The present study demonstrates that the prolidase activity in fibroblasts may reflect the chemotactic activity of the cells and suggests that the mechanism of cell locomotion may involve lysosomal enzyme targeting, probably through IGF-II/mannose 6-phosphate receptor.

Prolidase and prolinase activities in moderately and poorly differentiated lung adenocarcinoma.

Prolidase (E.C.3.4.13.9) and prolinase (E.C.3.4.13.8) activities were determined in normal human lung and human lung adenocarcinomas of various degree of histologic differentiation. Since these dipeptidases were found to be enzymes catabolizing mainly collagen and simultaneously involved in the recycling of proline for collagen biosynthesis, the measurement of this protein and its degradation products in studied tissues (by hydroxyproline determination) was performed. It has been found that the activity of prolinase in G2-moderately and G3-poorly differentiated lung adenocarcinoma groups, was elevated compared to lung parenchyma and that the increase was proportional to the degree of adenocarcinoma differentiation. Prolidase activity was elevated only in G3 lung adenocarcinoma. The increase of prolidase and prolinase activities were accompanied by an increase of tissue collagen content. Collagen degradation products (CDP) represented one third of total collagen in control lung tissues while in lung adenocarcinomas the CDP represented significantly lower percentage of total tissue collagen. The results suggest that prolidase and prolinase activities may reflect: (i) degree of differentiation of lung adenocarcinoma and (ii) disturbances in tissue collagen metabolism.

Prolidase activity and beta 1 integrin expression in moderately and poorly differentiated lung adenocarcinomas.

Primary human lung adenocarcinomas were divided into two groups according to the degree of histologic differentiation: G2-moderately and G3-poorly differentiated tumors. Each group was compared with normal lung tissue in respect to prolidase activity, its ability to interact with specific antibody, free proline and beta 1 integrin subunit content as well as ability of beta 1 integrin subunit to interact with specific antibody. It was found that prolidase activity in lung adenocarcinomas G3, was significantly elevated in comparison to normal lung tissue. In lung adenocarcinoma G2 no significant changes in the enzyme activity were observed. Increase in the enzyme activity was accompanied by increase of free proline content in the tissues. The western blot analysis revealed that prolidase of lung adenocarcinomas is identical to prolidase originated in control lung tissue. It was noticed that elevated activity of prolidase in adenocarcinomas G3 was accompanied by its high expression. In respect to beta 1 integrin expression, known to play an important role in metastasis, no difference was found between adenocarcinoma groups and the control lung tissue. The presented data suggest that the level of prolidase activity in lung adenocarcinoma may serve as a more sensitive marker for the histologic degree of malignancy, than the level of beta 1 integrin expression.

Modulation of prolidase activity during in vitro aging of human skin fibroblasts the role of extracellular matrix collagen.

The mechanism related to the decrease in the number of fibroblasts in the dermis during aging and the decrease in the biosynthetic capacity of existing fibroblasts to produce collagen is not known. Since prolidase [E. C. 3. 4. 13. 9] has been found to play an important role in the recycling of proline for collagen synthesis and cell growth, we performed comparative studies on prolidase activity and extracellular collagen content in in vitro aged human skin fibroblasts. We found that during aging of human skin fibroblasts there is a correlated decrease of prolidase activity and extracellular collagen content. The correlation is bifunctional. Decrease in prolidase activity contributes to decrease of extracellular collagen content, and removal of extracellular collagen form cultured fibroblasts contributes to a decrease of fibroblast prolidase activity. Using plates coated with different ECM proteins, it was found that extracellular type I collagen in cultured fibroblasts was the most potent activator of intracellular prolidase activity. Our results demonstrate that during in vitro aging of human skin fibroblasts, the prolidase activity of fibroblasts decreases. This phenomenon may be related to the reduced number of fibroblasts and decrease of extracellular collagen content in in vitro aging of the cells.

Inhibition of prolidase activity by non-steroid antiinflammatory drugs in cultured human skin fibroblasts.

Prolidase [E.C. 3.4.13.9] is a cytosolic enzyme which specifically splits imidodipeptides with C-terminal proline or hydroxyproline. This enzyme plays an important role in the recycling of proline for collagen biosynthesis and cell growth. Prolidase activity was measured in cultured human skin fibroblasts, treated with some non-steroid antiinflammatory drugs (acetyl-salicylic acid, sodium salicylate, phenylbutazone, indometacin). It was found that 24 h treatment of confluent cells with the examined drugs induced significant, dose dependent decrease in the fibroblast's prolidase activity. Simultaneously, the antiinflammatory drugs inhibited collagen biosynthesis and decreased extracellular content of this protein in extracellular matrix produced by fibroblasts. These observations suggest that non-steroid antiinflammatory drugs affect the metabolism of collagen through inhibition of prolidase activity in the collagen synthesizing cells.