Inhibitors of Urokinase Type Plasminogen Activator and Cytostatic Activity from Crude Plants Extracts

Abstract

In view of the clear evidence that urokinase type plasminogen activator (uPA) plays an important role in the processes of tumor cell metastasis, aortic aneurysm, and multiple sclerosis, it has become a target of choice for pharmacological intervention. The goal of this study was thus to determine the presence of inhibitors of uPA in plants known traditionally for their anti-tumor properties. Crude methanol extracts were prepared from the leaves of plants (14) collected from the subtropical dry forest (Guanica, Puerto Rico), and tested for the presence of inhibitors of uPA using the fibrin plate assay. The extracts that tested positive (6) were then partitioned with petroleum ether, chloroform, ethyl acetate and n-butanol, in a sequential manner. The resulting fractions were then tested again using the fibrin plate assay. Extracts from leaves of Croton lucidus (C. lucidus) showed the presence of a strong uPA inhibitory activity. Serial dilutions of these C. lucidus partitions were performed to determine the uPA inhibition IC50 values. The chloroform extract showed the lowest IC50 value (3.52 μg/mL) and hence contained the most potent uPA inhibitor. Further investigations revealed that the crude methanol extract and its chloroform and n-butanol partitions did not significantly inhibit closely related proteases such as the tissue type plasminogen activator (tPA) and plasmin, indicating their selectivity for uPA, and hence superior potential for medicinal use with fewer side effects. In a further evaluation of their therapeutic potential for prevention of cancer metastasis, the C. lucidus extracts displayed cytostatic activity against human pancreatic carcinoma (PaCa-2) cells, as determined through an MTS assay. The cytostatic activities recorded for each of the partitions correlated with their relative uPA inhibitory activities. There are no existing reports of uPA inhibitors being present in any of the plants reported in this study.

Potential hemostatic compounds targeting urokinase plasminogen activator explored from three Euphorbiaceae species: Euphorbia maculata, Euphorbia humifusa, and Acalypha australis, with bio‐affinity ultrafiltration UPLC‐MS

“…These findings suggest that these species can act as hemostatics by impeding the fibrinolysis process, and diverse potential uPA inhibitors may occur in these medicinal species. These outcomes are in agreement with a prior study on uPA inhibition activity of a Euphorbiaceae species, Croton lucidus , which showed a pronounced half‐maximal inhibitory effect against urokinase 33 . Furthermore, it was established that the oral administration of A. australis extracts regulates fibrinolysis and decreases platelet numbers, which account for the species' hemostatic effect 30 .…”

“…These outcomes are in agreement with a prior study on uPA inhibition activity of a Euphorbiaceae species, Croton lucidus, which showed a pronounced halfmaximal inhibitory effect against urokinase. 33 regulates fibrinolysis and decreases platelet numbers, which account for the species' hemostatic effect. 30 As a result, this work contributes to the expanding repository of knowledge about the three Euphorbiaceae species' hemostatic properties.…”

Antioxidant and Proteinase Inhibitory Activities of Selected Poppy (Papaver somniferum L.) Genotypes

“…It is very specific genotype due to high production of alkaloids in poppy‐heads, however, less‐favoured for consumption due to lower sensory parameters of seeds than special food cultivars. The IA_UR has been detected in extracts from many tropical plants and temperate medicinal plants such as Acer platanoides and Rhus typhina . Some commonly grown crops were also studied and were found to be interesting from the point of view of the IA_UR.…”

Engineered Antibody Fragment against the Urokinase Plasminogen Activator for Fast Delineation of Triple-Negative Breast Cancer by Positron Emission Tomography

“…Docetaxel was used as the drug of interest due to the possible correlation with uPA changes post drug administration. − During this initial test, we found a clear correlation between 64 Cu-NOTA-ATN-291 F­(ab′) 2 tumor uptake and uPA level measured by western blot (Figure ), although the uPA changes were not considered as statistically significant. Recent studies have continuously revealed the important roles of the uPA during the anticancer drug treatment, for example, sorafenib, gemcitabine, and anticancer plant-derived chemicals, among many others. These results further confirmed that 64 Cu-NOTA-ATN-291-F­(ab′) 2 could delineate the uPA expression level after a treatment plan was set, and this can be extremely useful to evaluate especially treatments available specifically against the uPA or uPAR system, since it can give an objective uPA information before any morphological or size changes in tissues.…”