Limits...
Cytotoxicity of cyclodipeptides from Pseudomonas aeruginosa PAO1 leads to apoptosis in human cancer cell lines.

Vázquez-Rivera D, González O, Guzmán-Rodríguez J, Díaz-Pérez AL, Ochoa-Zarzosa A, López-Bucio J, Meza-Carmen V, Campos-García J - Biomed Res Int (2015)

Bottom Line: Our results demonstrated that the CDP mix promoted cell death in cultures of the HeLa cervical adenocarcinoma and Caco-2 colorectal adenocarcinoma cell lines in a dose-dependent manner, with a 50% inhibitory concentration (IC50) of 0.53 and 0.66 mg/mL, for HeLa and Caco-2 cells, respectively.IC50 values for apoptotic cells in HeLa and Caco-2 cells were 6.5 × 10(-5) and 1.8 × 10(-4) mg/mL, respectively.Our results indicate that an apoptotic pathway is involved in the inhibition of cell proliferation caused by the P. aeruginosa CDP mix.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo (UMSNH), Edificio B-3, Ciudad Universitaria, 58030 Morelia, MICH, Mexico.

ABSTRACT
Pseudomonas aeruginosa is an opportunistic pathogen of plants and animals, which produces virulence factors in order to infect or colonize its eukaryotic hosts. Cyclodipeptides (CDPs) produced by P. aeruginosa exhibit cytotoxic properties toward human tumor cells. In this study, we evaluated the effect of a CDP mix, comprised of cyclo(L-Pro-L-Tyr), cyclo(L-Pro-L-Val), and cyclo(L-Pro-L-Phe) that were isolated from P. aeruginosa, on two human cancer cell lines. Our results demonstrated that the CDP mix promoted cell death in cultures of the HeLa cervical adenocarcinoma and Caco-2 colorectal adenocarcinoma cell lines in a dose-dependent manner, with a 50% inhibitory concentration (IC50) of 0.53 and 0.66 mg/mL, for HeLa and Caco-2 cells, respectively. Flow cytometric analysis, using annexin V and propidium iodide as apoptosis and necrosis indicators, respectively, clearly showed that HeLa and Caco-2 cells exhibited apoptotic characteristics when treated with the CDP mix at a concentration <0.001 mg/mL. IC50 values for apoptotic cells in HeLa and Caco-2 cells were 6.5 × 10(-5) and 1.8 × 10(-4) mg/mL, respectively. Our results indicate that an apoptotic pathway is involved in the inhibition of cell proliferation caused by the P. aeruginosa CDP mix.

Show MeSH

Related in: MedlinePlus

Effect of cyclodipeptides from Pseudomonas aeruginosa on HeLa and Caco-2 cell viability. HeLa and Caco-2 cells were incubated in CM medium containing the CDP mix for 24 h. (a) Viability was determined by the MTT assay and quantitation of fluorescence. Bars represent the mean value ± the standard error (SE) of three independent experiments. One-way analysis of variance was carried out, with Tukey's post hoc test; n = 6. Values for SE (P < 0.05) are shown in lowercase letters. (b) Nonlinear regression analysis of dose-response for the inhibition of viability by the CDP mix; 95% confidence interval, P < 0.001. HeLa: 50% inhibitory concentration (IC50) = 0.53 mg/mL; R2 = 0.96. Caco-2: IC50 = 0.66 mg/mL, R2 = 0.93.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4363556&req=5

fig2: Effect of cyclodipeptides from Pseudomonas aeruginosa on HeLa and Caco-2 cell viability. HeLa and Caco-2 cells were incubated in CM medium containing the CDP mix for 24 h. (a) Viability was determined by the MTT assay and quantitation of fluorescence. Bars represent the mean value ± the standard error (SE) of three independent experiments. One-way analysis of variance was carried out, with Tukey's post hoc test; n = 6. Values for SE (P < 0.05) are shown in lowercase letters. (b) Nonlinear regression analysis of dose-response for the inhibition of viability by the CDP mix; 95% confidence interval, P < 0.001. HeLa: 50% inhibitory concentration (IC50) = 0.53 mg/mL; R2 = 0.96. Caco-2: IC50 = 0.66 mg/mL, R2 = 0.93.

Mentions: In order to test the effect of CDPs from P. aeruginosa on mammalian cell growth, we used the HeLa and the Caco-2 cell lines as models in this study. The HeLa cell line has been extensively employed to test anticancer drugs [24], while the Caco-2 cell line has been used to evaluate the ability of chemicals to cross the intestinal barrier and to study their transport mechanisms [25]. A mixture of CDPs, mainly comprised of cyclo(L-Pro-L-Tyr), cyclo(L-Pro-L-Val), and cyclo(L-Pro-L-Phe) in a 1 : 1 : 1 molar ratio, was isolated from the P. aeruginosa PAO1 strain, grown on Luria Bertani broth. The CDP mix was applied in a dose-dependent manner to human cells grown in CM medium. The results obtained showed that CDPs caused a decrease in the viability of HeLa and Caco-2 cells in a dose-dependent manner, cell cultures exhibiting 75% dead cells following treatment with the CDP mix at 100 mg/mL (Figure 2(a)). The 50% inhibitory concentration (IC50) for the CDP mix from the PAO1 strain was 0.53 and 0.66 mg/mL, for HeLa and Caco-2 cells, respectively (Figure 2(b)). Although CDPs incubated in serum-free (SS) medium showed slight differences in activity compared to those incubated in serum-containing (CM) medium, these differences were not significant (see Figure S1 in Supplementary Material available online at http://dx.doi.org/10.1155/2015/197608). These findings indicate that the CDP mix from P. aeruginosa inhibited the viability of HeLa and Caco-2 cells and that this effect was independent of the presence or absence of serum.


Cytotoxicity of cyclodipeptides from Pseudomonas aeruginosa PAO1 leads to apoptosis in human cancer cell lines.

Vázquez-Rivera D, González O, Guzmán-Rodríguez J, Díaz-Pérez AL, Ochoa-Zarzosa A, López-Bucio J, Meza-Carmen V, Campos-García J - Biomed Res Int (2015)

Effect of cyclodipeptides from Pseudomonas aeruginosa on HeLa and Caco-2 cell viability. HeLa and Caco-2 cells were incubated in CM medium containing the CDP mix for 24 h. (a) Viability was determined by the MTT assay and quantitation of fluorescence. Bars represent the mean value ± the standard error (SE) of three independent experiments. One-way analysis of variance was carried out, with Tukey's post hoc test; n = 6. Values for SE (P < 0.05) are shown in lowercase letters. (b) Nonlinear regression analysis of dose-response for the inhibition of viability by the CDP mix; 95% confidence interval, P < 0.001. HeLa: 50% inhibitory concentration (IC50) = 0.53 mg/mL; R2 = 0.96. Caco-2: IC50 = 0.66 mg/mL, R2 = 0.93.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4363556&req=5

fig2: Effect of cyclodipeptides from Pseudomonas aeruginosa on HeLa and Caco-2 cell viability. HeLa and Caco-2 cells were incubated in CM medium containing the CDP mix for 24 h. (a) Viability was determined by the MTT assay and quantitation of fluorescence. Bars represent the mean value ± the standard error (SE) of three independent experiments. One-way analysis of variance was carried out, with Tukey's post hoc test; n = 6. Values for SE (P < 0.05) are shown in lowercase letters. (b) Nonlinear regression analysis of dose-response for the inhibition of viability by the CDP mix; 95% confidence interval, P < 0.001. HeLa: 50% inhibitory concentration (IC50) = 0.53 mg/mL; R2 = 0.96. Caco-2: IC50 = 0.66 mg/mL, R2 = 0.93.
Mentions: In order to test the effect of CDPs from P. aeruginosa on mammalian cell growth, we used the HeLa and the Caco-2 cell lines as models in this study. The HeLa cell line has been extensively employed to test anticancer drugs [24], while the Caco-2 cell line has been used to evaluate the ability of chemicals to cross the intestinal barrier and to study their transport mechanisms [25]. A mixture of CDPs, mainly comprised of cyclo(L-Pro-L-Tyr), cyclo(L-Pro-L-Val), and cyclo(L-Pro-L-Phe) in a 1 : 1 : 1 molar ratio, was isolated from the P. aeruginosa PAO1 strain, grown on Luria Bertani broth. The CDP mix was applied in a dose-dependent manner to human cells grown in CM medium. The results obtained showed that CDPs caused a decrease in the viability of HeLa and Caco-2 cells in a dose-dependent manner, cell cultures exhibiting 75% dead cells following treatment with the CDP mix at 100 mg/mL (Figure 2(a)). The 50% inhibitory concentration (IC50) for the CDP mix from the PAO1 strain was 0.53 and 0.66 mg/mL, for HeLa and Caco-2 cells, respectively (Figure 2(b)). Although CDPs incubated in serum-free (SS) medium showed slight differences in activity compared to those incubated in serum-containing (CM) medium, these differences were not significant (see Figure S1 in Supplementary Material available online at http://dx.doi.org/10.1155/2015/197608). These findings indicate that the CDP mix from P. aeruginosa inhibited the viability of HeLa and Caco-2 cells and that this effect was independent of the presence or absence of serum.

Bottom Line: Our results demonstrated that the CDP mix promoted cell death in cultures of the HeLa cervical adenocarcinoma and Caco-2 colorectal adenocarcinoma cell lines in a dose-dependent manner, with a 50% inhibitory concentration (IC50) of 0.53 and 0.66 mg/mL, for HeLa and Caco-2 cells, respectively.IC50 values for apoptotic cells in HeLa and Caco-2 cells were 6.5 × 10(-5) and 1.8 × 10(-4) mg/mL, respectively.Our results indicate that an apoptotic pathway is involved in the inhibition of cell proliferation caused by the P. aeruginosa CDP mix.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo (UMSNH), Edificio B-3, Ciudad Universitaria, 58030 Morelia, MICH, Mexico.

ABSTRACT
Pseudomonas aeruginosa is an opportunistic pathogen of plants and animals, which produces virulence factors in order to infect or colonize its eukaryotic hosts. Cyclodipeptides (CDPs) produced by P. aeruginosa exhibit cytotoxic properties toward human tumor cells. In this study, we evaluated the effect of a CDP mix, comprised of cyclo(L-Pro-L-Tyr), cyclo(L-Pro-L-Val), and cyclo(L-Pro-L-Phe) that were isolated from P. aeruginosa, on two human cancer cell lines. Our results demonstrated that the CDP mix promoted cell death in cultures of the HeLa cervical adenocarcinoma and Caco-2 colorectal adenocarcinoma cell lines in a dose-dependent manner, with a 50% inhibitory concentration (IC50) of 0.53 and 0.66 mg/mL, for HeLa and Caco-2 cells, respectively. Flow cytometric analysis, using annexin V and propidium iodide as apoptosis and necrosis indicators, respectively, clearly showed that HeLa and Caco-2 cells exhibited apoptotic characteristics when treated with the CDP mix at a concentration <0.001 mg/mL. IC50 values for apoptotic cells in HeLa and Caco-2 cells were 6.5 × 10(-5) and 1.8 × 10(-4) mg/mL, respectively. Our results indicate that an apoptotic pathway is involved in the inhibition of cell proliferation caused by the P. aeruginosa CDP mix.

Show MeSH
Related in: MedlinePlus