CONCLUSION: Overall, this review discusses some of the previously studied and reported natural products and their mechanisms of action which may potentially be redirected into ADPKD.
PURPOSE: Our previous proteomics analysis revealed that treatment with PA resulted in the upregulation of an autophagy marker, LC3B in melanoma cells. Therefore, the present study sought to investigate the role of PA-induced autophagy in melanoma cells.
METHODS: Transmission electron microscopy was performed for examination of autophagic ultra-structures in PA-treated A375 cells. Cytoplasmic LC3B and p62/SQSMT1 punctate structures were detected using immunofluorescene staining. Expression levels of LC3B II, p62/SQSMT1, ATG 12, Beclin 1, phospho S6 (ser235/236), phospho AMPK (Thr172) and cleaved PARP were evaluated by western blotting.
RESULTS: Autophagosomes, autolysosomes and punctuates of LC3 proteins could be observed in PA-treated A375 cells. PA-induced autophagy in A375 melanoma cells was found to be mediated through the inhibition of mTOR signaling and activation of AMPK pathway. Furthermore, we showed that PA-induced apoptosis was increased in the presence of an autophagy inhibitor, signifying the cytoprotective effect of PA-induced autophagy in melanoma cells.
CONCLUSION: Taken together, results from the present study suggest that the inhibition of autophagy by targeting mTOR and AMPK could potentiate the cytotoxicity effects of PA on melanoma cells.
METHODOLOGY/PRINCIPAL FINDINGS: PA exerted selective cytotoxicity on human umbilical vein endothelial cells (HUVECs) with IC(50) value of 6.91 ± 0.85 µM when compared to human normal fibroblast and normal liver epithelial cells. Assessment of the growth kinetics by cell impedance-based Real-Time Cell Analyzer showed that PA induced both cytotoxic and cytostatic effects on HUVECs, depending on the concentration used. Results also showed that PA suppressed VEGF-induced survival and proliferation of HUVECs. Furthermore, endothelial cell migration, invasion, and morphogenesis or tube formation demonstrated significant time- and dose-dependent inhibition by PA. PA also suppressed matrix metalloproteinase-2 (MMP-2) secretion and attenuated its activation to intermediate and active MMP-2. In addition, PA suppressed F-actin stress fiber formation to prevent migration of the endothelial cells. More importantly, anti-angiogenic potential of PA was also evidenced in two in vivo models. PA inhibited neo-vessels formation in murine Matrigel plugs, and angiogenesis in zebrafish embryos.
CONCLUSIONS/SIGNIFICANCE: Taken together, our study demonstrated the distinctive anti-angiogenic properties of PA, both in vitro and in vivo. This report thus reveals another biological activity of PA in addition to its reported anti-inflammatory and anti-cancer activities, suggestive of PA's potential for development as an anti-angiogenic agent for cancer therapy.
OBJECTIVE: In order to investigate the influence between electron density in conjugated π-systems and biological activities, different withdrawing substituents, namely Nitro (NO2), Cyano (C≡N) and trifluoromethyl (CF3) were introduced in the chalcone-based molecular system.
METHODS: All the derivatives were then tested on MCF-7 cell line using the fluorescence microscopy-based cytotoxicity analyses.
RESULTS: The preliminary findings showed that both -NO2 and -CF3 substituents revealed their potential to inhibit the growth of MCF-7 with IC;50 values of 14.75 and 13.75 μg/ml, respectively. In addition, the morphological changes of MCF-7 cells were observed in response to alkoxy substituted chalcone treatment through an induction of apoptosis pathway with cell blebbing, phosphatidylserine exposure and autophagic activity with acidification of lysosomal structure. Intermolecular interaction based on in silico investigation on nitro, trifluoromethyl and cyano based chalcones exhibited several types of interactions with tumor necrosis factor receptor (PDB: 1EXT) protein and high hydrogen bond in the molecule-receptor interaction have given significant impact towards their toxicity on MCF-7 cells.
CONCLUSION: Significantly, these types of chalcones exhibited ideal and high potential to be further developed as anti-cancer agents.