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Procyanidins Negatively Affect the Activity of the Phosphatases of Regenerating Liver.

Stadlbauer S, Rios P, Ohmori K, Suzuki K, Köhn M - PLoS ONE (2015)

Bottom Line: Increasing the number of catechin units in procyanidins to more than three does not further enhance the potency.As PRL overexpression induces cell migration compared to control cells, the effect of procyanidins on this phenotype was studied.Together, our results show that procyanidins negatively affect PRL activity, suggesting that PRLs could be targets in the polypharmacology of natural polyphenols.

View Article: PubMed Central - PubMed

Affiliation: European Molecular Biology Laboratory, Genome Biology Unit, Meyerhofstrasse 1, 69117, Heidelberg, Germany.

ABSTRACT
Natural polyphenols like oligomeric catechins (procyanidins) derived from green tea and herbal medicines are interesting compounds for pharmaceutical research due to their ability to protect against carcinogenesis in animal models. It is nevertheless still unclear how intracellular pathways are modulated by polyphenols. Monomeric polyphenols were shown to affect the activity of some protein phosphatases (PPs). The three phosphatases of regenerating liver (PRLs) are close relatives and promising therapeutic targets in cancer. In the present study we show that several procyanidins inhibit the activity of all three members of the PRL family in the low micromolar range, whereas monomeric epicatechins show weak inhibitory activity. Increasing the number of catechin units in procyanidins to more than three does not further enhance the potency. Remarkably, the tested procyanidins showed selectivity in vitro when compared to other PPs, and over 10-fold selectivity toward PRL-1 over PRL-2 and PRL-3. As PRL overexpression induces cell migration compared to control cells, the effect of procyanidins on this phenotype was studied. Treatment with procyanidin C2 led to a decrease in cell migration of PRL-1- and PRL-3-overexpressing cells, suggesting the compound-dependent inhibition of PRL-promoted cell migration. Treatment with procyanidin B3 led to selective suppression of PRL-1 overexpressing cells, thereby corroborating the selectivity toward PRL-1- over PRL-3 in vitro. Together, our results show that procyanidins negatively affect PRL activity, suggesting that PRLs could be targets in the polypharmacology of natural polyphenols. Furthermore, they are interesting candidates for the development of PRL-1 inhibitors due to their low cellular toxicity and the selectivity within the PRL family.

No MeSH data available.


Related in: MedlinePlus

Effect of procyanidin C2 (9) on the phosphatase activity of VHR, PTP1B and TCPTP using DiFMUP as a substrate [44].Proteins were incubated with compound 9 for 30 min., phosphatase activity measurements were performed using 20 μM DiFMUP. Phosphatase activity in the absence of compound 9 was set as 100%. Data represent means ± standard errors of the mean (n = 3).
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pone.0134336.g003: Effect of procyanidin C2 (9) on the phosphatase activity of VHR, PTP1B and TCPTP using DiFMUP as a substrate [44].Proteins were incubated with compound 9 for 30 min., phosphatase activity measurements were performed using 20 μM DiFMUP. Phosphatase activity in the absence of compound 9 was set as 100%. Data represent means ± standard errors of the mean (n = 3).

Mentions: As an extension of our studies we included PTP1B, VHR and TCPTB as examples for phosphotyrosine specific phosphatases in our activity studies, because tea extracts were reported to inhibit PTP1B [43]. For comparison with PRL-3, these proteins were used in the same concentration (50 nM) as PRL-3 and DiFMUP was also used as a substrate in 20 μM concentration [44]. The enzymes were incubated with three different concentrations of procyanidin C2 (9) for 30 min before the measurement. The data obtained (Fig 3), show that at 12.5 μM, phosphatase activity was reduced to 75–85% compared to the control, but there was no significant difference in activity suppression between PRL-3 and the other phosphatases. However, at 25 μM and 50 μM the activity of PRL-3 was inhibited in a concentration dependent manner whereas the three tested PTPs were not, showing that the compound is selective toward PRL-3 over the other three phosphatases. These results show that procyanidin C2 does not randomly inhibit any PTP, but is active toward the PRLs.


Procyanidins Negatively Affect the Activity of the Phosphatases of Regenerating Liver.

Stadlbauer S, Rios P, Ohmori K, Suzuki K, Köhn M - PLoS ONE (2015)

Effect of procyanidin C2 (9) on the phosphatase activity of VHR, PTP1B and TCPTP using DiFMUP as a substrate [44].Proteins were incubated with compound 9 for 30 min., phosphatase activity measurements were performed using 20 μM DiFMUP. Phosphatase activity in the absence of compound 9 was set as 100%. Data represent means ± standard errors of the mean (n = 3).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4520450&req=5

pone.0134336.g003: Effect of procyanidin C2 (9) on the phosphatase activity of VHR, PTP1B and TCPTP using DiFMUP as a substrate [44].Proteins were incubated with compound 9 for 30 min., phosphatase activity measurements were performed using 20 μM DiFMUP. Phosphatase activity in the absence of compound 9 was set as 100%. Data represent means ± standard errors of the mean (n = 3).
Mentions: As an extension of our studies we included PTP1B, VHR and TCPTB as examples for phosphotyrosine specific phosphatases in our activity studies, because tea extracts were reported to inhibit PTP1B [43]. For comparison with PRL-3, these proteins were used in the same concentration (50 nM) as PRL-3 and DiFMUP was also used as a substrate in 20 μM concentration [44]. The enzymes were incubated with three different concentrations of procyanidin C2 (9) for 30 min before the measurement. The data obtained (Fig 3), show that at 12.5 μM, phosphatase activity was reduced to 75–85% compared to the control, but there was no significant difference in activity suppression between PRL-3 and the other phosphatases. However, at 25 μM and 50 μM the activity of PRL-3 was inhibited in a concentration dependent manner whereas the three tested PTPs were not, showing that the compound is selective toward PRL-3 over the other three phosphatases. These results show that procyanidin C2 does not randomly inhibit any PTP, but is active toward the PRLs.

Bottom Line: Increasing the number of catechin units in procyanidins to more than three does not further enhance the potency.As PRL overexpression induces cell migration compared to control cells, the effect of procyanidins on this phenotype was studied.Together, our results show that procyanidins negatively affect PRL activity, suggesting that PRLs could be targets in the polypharmacology of natural polyphenols.

View Article: PubMed Central - PubMed

Affiliation: European Molecular Biology Laboratory, Genome Biology Unit, Meyerhofstrasse 1, 69117, Heidelberg, Germany.

ABSTRACT
Natural polyphenols like oligomeric catechins (procyanidins) derived from green tea and herbal medicines are interesting compounds for pharmaceutical research due to their ability to protect against carcinogenesis in animal models. It is nevertheless still unclear how intracellular pathways are modulated by polyphenols. Monomeric polyphenols were shown to affect the activity of some protein phosphatases (PPs). The three phosphatases of regenerating liver (PRLs) are close relatives and promising therapeutic targets in cancer. In the present study we show that several procyanidins inhibit the activity of all three members of the PRL family in the low micromolar range, whereas monomeric epicatechins show weak inhibitory activity. Increasing the number of catechin units in procyanidins to more than three does not further enhance the potency. Remarkably, the tested procyanidins showed selectivity in vitro when compared to other PPs, and over 10-fold selectivity toward PRL-1 over PRL-2 and PRL-3. As PRL overexpression induces cell migration compared to control cells, the effect of procyanidins on this phenotype was studied. Treatment with procyanidin C2 led to a decrease in cell migration of PRL-1- and PRL-3-overexpressing cells, suggesting the compound-dependent inhibition of PRL-promoted cell migration. Treatment with procyanidin B3 led to selective suppression of PRL-1 overexpressing cells, thereby corroborating the selectivity toward PRL-1- over PRL-3 in vitro. Together, our results show that procyanidins negatively affect PRL activity, suggesting that PRLs could be targets in the polypharmacology of natural polyphenols. Furthermore, they are interesting candidates for the development of PRL-1 inhibitors due to their low cellular toxicity and the selectivity within the PRL family.

No MeSH data available.


Related in: MedlinePlus