Antiangiogenesis, loss of cell adhesion and apoptosis are involved in the antitumoral activity of Proteases from V. cundinamarcensis (C. candamarcensis) in murine melanoma B16F1

Chrysin Inhibits Melanoma Tumor Metastasis via Interfering with the FOXM1/β-Catenin Signaling

Melanoma, which features high metastasis and high lethality, is one of the toughest tumors to treat. Chrysin, which is rich in various plants, has shown a great inhibitory effect on melanoma proliferation. Here, we evaluated the metastasis suppressive effect of chrysin on melanoma in vivo and in vitro. In vitro, chrysin effectively inhibited ankios resistance from 5 μM cell migration, invasion from 10 μM, and tube formation capacity of melanoma cells from 20 μM. We discovered that chrysin interfered with the mesenchymal-epithelial transition via regulating FOXM1/β-catenin signaling, as the expression of key regulatory factors was downregulated by chrysin treatment, and overexpression of FOXM1 will attenuate the antimetastasis effect of chrysin. We also tested chrysin on lung colonization in melanoma metastasis, where we found fewer tumors were formed in the lungs of chrysin-treated mice. In addition, the expression of FOXM1 was also downregulated by chrysin in vivo. Collectively, our findings suggested the ability of chrysin treatment to lower the metastatic rate of melanoma through regulating FOXM1/β-catenin signaling, indicating the application potential of chrysin for melanoma therapy.

Cysteine Proteases from V. cundinamarcensis (C. candamarcensis) Inhibit Melanoma Metastasis and Modulate Expression of Proteins Related to Proliferation, Migration and Differentiation

Previous studies showed that P1G10, a proteolytic fraction from Vasconcellea cundinamarcensis latex, reduced the tumor mass in animals bearing melanoma, increased in vitro DNA fragmentation and decreased cell adhesion. Here, we present some molecular and cellular events related to the antimetastatic effect induced by the CMS-2 fraction derived from P1G10 in metastatic melanoma B16-F10 and melanocyte Melan-a. Using difference gel electrophoresis and mass spectrometry, we identified four proteins overexpressed in tumor cells, all of them related to proliferation, survival, migration and cell invasion, that had their expression normalized upon treatment with CMS-2: nucleophosmin 1, heat shock protein 65, calcyclin binding protein and eukaryotic translation initiation factor 4H. In addition, some antioxidant and glycolytic enzymes show increased expression after exposure to CMS-2, along with an induction of melanogenesis (differentiation marker). The down regulation of cofilin 1, a protein involved in cell motility, may explain the inhibition of cell migration and dendritic-like outgrowth in B16-F10 and Melan-a, observed after CMS-2 treatment. Taken together, it is argued that CMS-2 modulates the expression of proteins related to metastatic development, driving the cell to a more differentiated-like state. These effects support the CMS-2 antimetastatic activity and place this fraction in the category of anticancer agent.

Pinocembrin induces ER stress mediated apoptosis and suppresses autophagy in melanoma cells

Melanoma, one of the toughest tumors to treat, features high metastasis and high lethality. Pinocembrin is a natural flavanone with versatile biological and pharmacological activities. Here, we evaluated the anti-tumor effects of pinocembrin against melanoma in vitro and in vivo. In vitro, pinocembrin inhibited the proliferation of melanoma cells (B16F10 and A375) in a dose-dependent manner. It induced endoplasmic reticulum stress via IRE1α/Xbp1 pathway and triggered caspase-12/-4 mediated apoptosis in both cell lines. Furthermore, we discovered that pinocembrin suppressed autophagy through the activation of PI3K/Akt/mTOR pathway, which serves as a dual mechanism to enhance the pro-death effect of pinocembrin. In vivo, pinocembrin inhibited the growth of B16F10 by inducing apoptosis. Taken together, our results demonstrated that pinocembrin can induce ER stress mediated apoptosis and suppress autophagy in melanoma, indicating its application potential for melanoma therapy.

Trends and Prospects of Plant Proteases in Therapeutics

The main function of proteases in any living organism is the cleavage of proteins resulting in the degradation of damaged, misfolded and potentially harmful proteins and therefore providing the cell with amino acids essential for the synthesis of new proteins. Besides this main function, proteases may play an important role as signal molecules and participate in numerous protein cascades to maintain the vital processes of an organism. Plant proteases are no exception to this rule. Moreover, in contrast to humanencoded enzymes, many plant proteases possess exceptional features such as higher stability, unique substrate specificity and a wide pH range for enzymatic activity. These valuable features make plant-derived proteolytic enzymes suitable for many biomedical applications, and furthermore, the plants can serve as factories for protein production. Plant proteases are already applied in the treatment of several pathological conditions in the human organism. Some of the enzymes possess antitumour, antibacterial and antifungal activity. The collagenolytic activity of plant proteases determines important medical applications such as the healing of wounds and burn debridement. Plant proteases may affect blood coagulation processes and can be applied in the treatment of digestive disorders. The present review summarizes recent advances and possible applications for plant proteases in biomedicine, and proposes further development of plant-derived proteolytic enzymes in the biotechnology and pharmaceutical industries.

The biochemical characterization, stabilization studies and the antiproliferative effect of bromelain against B16F10 murine melanoma cells

The current study aims to extract bromelain from different parts (stem, crown, peels, pulp and leaves) of Ananas comosus var. comosus AGB 772; to determine of optimum pH and temperature; to test bromelain stability in disodium EDTA and sodium benzoate, and to investigate its pharmacological activity on B16F10 murine melanoma cells in vitro. The highest enzymatic activity was found in bromelain extracted from the pulp and peel. The optimum bromelain pH among all studied pineapple parts was 6.0. The optimum temperature was above 50 °C in all bromelain extracts. The fluorescence analysis confirmed the stability of bromelain in the presence of EDTA and sodium benzoate. Bromelain was pharmacologically active against B16F10 melanoma cells and it was possible verifying approximately 100% inhibition of tumor cell proliferation in vitro. Since bromelain activity was found in different parts of pineapple plants, pineapple residues from the food industry may be used for bromelain extraction.