ginkgolic-acid and Neoplasms

SUMOylation is a key post-translational modification that involves the covalent attachment of small ubiquitin-like modifier (SUMO) to the lysine residues of target proteins. The well-balanced SUMOylation is essential for normal cellular behaviors, while disturbance of SUMOylation is associated with various cancers and other diseases. Herein, we summarize the structures and biological functions of proteins involved in the SUMOylation process, their dysregulation in human diseases, and the discovery of small-molecular inhibitors targeting this pathway. In addition, we highlight the emerging trends in this field.

Topics: Humans; Neoplasms; Protein Processing, Post-Translational; Small Ubiquitin-Related Modifier Proteins; Sumoylation; Ubiquitin

The oxidative pentose phosphate pathway (PPP) contributes to tumour growth, but the precise contribution of 6-phosphogluconate dehydrogenase (6PGD), the third enzyme in this pathway, to tumorigenesis remains unclear. We found that suppression of 6PGD decreased lipogenesis and RNA biosynthesis and elevated ROS levels in cancer cells, attenuating cell proliferation and tumour growth. 6PGD-mediated production of ribulose-5-phosphate (Ru-5-P) inhibits AMPK activation by disrupting the active LKB1 complex, thereby activating acetyl-CoA carboxylase 1 and lipogenesis. Ru-5-P and NADPH are thought to be precursors in RNA biosynthesis and lipogenesis, respectively; thus, our findings provide an additional link between the oxidative PPP and lipogenesis through Ru-5-P-dependent inhibition of LKB1-AMPK signalling. Moreover, we identified and developed 6PGD inhibitors, physcion and its derivative S3, that effectively inhibited 6PGD, cancer cell proliferation and tumour growth in nude mice xenografts without obvious toxicity, suggesting that 6PGD could be an anticancer target.

Topics: AMP-Activated Protein Kinase Kinases; AMP-Activated Protein Kinases; Humans; Lipogenesis; Neoplasms; Oxidative Stress; Pentose Phosphate Pathway; Phosphogluconate Dehydrogenase; Protein Serine-Threonine Kinases; Ribulosephosphates; Signal Transduction

The labeling of proteins with small ubiquitin (Ub) and ubiquitin-like (Ubl) modifiers regulates a plethora of activities within the cell, such as protein recycling, cell cycle modifications, and protein translocation. These processes are often overactive in diseased cells, leading to unregulated cell growth and disease progression. Therefore, in systems where Ub/Ubl protein labeling is dysregulated, the development of drugs to selectively and potently disrupt Ub/Ubl protein labeling offers a targeted molecular approach for sensitizing these diseased cells. This Perspective outlines the progress that has been made in the context of inhibitor development for targeting Ub/Ubl pathways.

Topics: Animals; Antineoplastic Agents; Humans; Molecular Targeted Therapy; Neoplasms; Ubiquitin; Ubiquitin-Activating Enzymes

Ginkgolic acid (GA) is a botanical drug extracted from the seed coat of Ginkgo biloba L. with a wide range of bioactive properties, including anti-tumor effect. However, whether GA has antitumor effect on pancreatic cancer cells and the underlying mechanisms have yet to be investigated. In this study, we show that GA suppressed the viability of cancer cells but has little toxicity on normal cells, e.g, HUVEC cells. Furthermore, treatment of GA resulted in impaired colony formation, migration, and invasion ability and increased apoptosis of cancer cells. In addition, GA inhibited the de novo lipogenesis of cancer cells through inducing activation of AMP-activated protein kinase (AMPK) signaling and downregulated the expression of key enzymes (e.g. acetyl-CoA carboxylase [ACC], fatty acid synthase [FASN]) involved in lipogenesis. Moreover, the in vivo experiment showed that GA reduced the expression of the key enzymes involved in lipogenesis and restrained the tumor growth. Taken together, our results suggest that GA may serve as a new candidate against tumor growth of pancreatic cancer partially through targeting pathway driving lipogenesis.

Topics: Acetyl-CoA Carboxylase; AMP-Activated Protein Kinases; Animals; Apoptosis; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Fatty Acid Synthases; Ginkgo biloba; Hep G2 Cells; Human Umbilical Vein Endothelial Cells; Humans; Lipogenesis; Male; Mice; Mice, Inbred BALB C; Neoplasm Invasiveness; Neoplasms; Pancreatic Neoplasms; RNA Interference; Salicylates; Signal Transduction

Ginkgolic acids (GAs), extracted from the seed coat of Ginkgo biloba L. Our previous study has shown that GA monomer could inhibit the growth of Hep-2 significantly and induce the fragmentation of the chromosomal DNA. To further assess the antitumor potential and turn it into a candidate new antitumor drug, the antitumor mechanism of GA was investigated.. The cytotoxicity and antitumor effect of GA monomer were assayed by MTT colorimetric assay with nontumorogenic MC-3T3-E1 as well as tumorogenic Hep-2 and Tac8113 cell lines. The effect of GA monomer on the proliferation of tumor cell lines was analyzed with MTT colorimetric and CFSE labeled assay. Cell cycle distribution and measurement of the percentage of apoptotic cells were performed by flow cytometry following stained with propidium iodide, annexin V-FITC. The expression of apoptotic proteins Bcl-2, Bax and caspase-3 was analyzed with Western blot.. GA only inhibited the growth of tumorogenic cell lines in a both dose- and time-dependent manner. Tumor cells were treated with GA for 72 h, 70.53 ± 4.54% Hep-2 and 63.5 ± 7.2% Tca8113 cells were retarded at GO/G1 phase, and the percentage of apoptosis was 40.4 ± 1.58 and 38.4 ± 1.7%, respectively. GA-treated activated caspase-3 downregulated the expression of anti-apoptotic Bcl-2 protein and upregulated the expression of pro-apoptotic Bax protein, eventually leading to a decrease in the Bcl-2/Bax ratio in tumor cells.. The antitumor action of GA was due to inhibiting the proliferation in a manner of inhibiting division, retarding the progress of cell cycle and inducing apoptosis, making GA a candidate as new antitumor drug.

Topics: Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Cell Line, Tumor; Colorimetry; Flow Cytometry; G1 Phase; Humans; Neoplasms; Proto-Oncogene Proteins c-bcl-2; Resting Phase, Cell Cycle; Salicylates