Ginkgolic acids induce HepG2 cell death via a combination of apoptosis, autophagy and the mitochondrial pathway

Role of non-canonical post-translational modifications in gastrointestinal tumors

Post-translational modifications (PTMs) of proteins contribute to the occurrence and development of tumors. Previous studies have suggested that canonical PTMs such as ubiquitination, glycosylation, and phosphorylation are closely implicated in different aspects of gastrointestinal tumors. Recently, emerging evidence showed that non-canonical PTMs play an essential role in the carcinogenesis, metastasis and treatment of gastrointestinal tumors. Therefore, we summarized recent advances in sumoylation, neddylation, isoprenylation, succinylation and other non-canonical PTMs in gastrointestinal tumors, which comprehensively describe the mechanisms and functions of non-classical PTMs in gastrointestinal tumors. It is anticipated that targeting specific PTMs could benefit the treatment as well as improve the prognosis of gastrointestinal tumors.

Natural compounds modulate the autophagy with potential implication of stroke

Stroke is considered a leading cause of mortality and neurological disability, which puts a huge burden on individuals and the community. To date, effective therapy for stroke has been limited by its complex pathological mechanisms. Autophagy refers to an intracellular degrading process with the involvement of lysosomes. Autophagy plays a critical role in maintaining the homeostasis and survival of cells by eliminating damaged or non-essential cellular constituents. Increasing evidence support that autophagy protects neuronal cells from ischemic injury. However, under certain circumstances, autophagy activation induces cell death and aggravates ischemic brain injury. Diverse naturally derived compounds have been found to modulate autophagy and exert neuroprotection against stroke. In the present work, we have reviewed recent advances in naturally derived compounds that regulate autophagy and discussed their potential application in stroke treatment.

Role of exopolysaccharides (EPSs) as anti-Mir-155 in cancer cells

Micro-RNAs (MiRNAs) are a class of small non-coding RNAs that regulate cellular gene expression. MiR-155 overexpression has been implicated in many types of cancer. Besides, miR-155 appears to help tumor invasion and migration and works as a moderator of epithelial-to-mesenchymal transition (EMT). Exopolysaccharides (EPSs) are a large group of natural heterogeneous polymers of sugars with a biologically antitumor effect. Herein, we test a hypothesis that EPS might promote its anti-tumorigenic effect via regulating miR-155 expression and its target pathways. Expression of miR-155 and a panel of targeted genes were investigated by real-time PCR. In our study, we have succeeded in the extraction, purification of exopolysaccharide with great cytotoxicity to different cancer cell lines, HepG II, Caco-2, and MCF-7. We reported that EPSs have a suppression effect on the oncogenic miR-155. In conclusion, this work clarifies a new possible mechanism for the anti-tumorigenic effect of EPSs in cancer cells and provides insights into the biological pathways through which EPSs act. Moreover, it paves the way for new prospective cancer therapeutics as anti-miRNA.

Natural Salicylates and Their Roles in Human Health

Salicylic acid (SA) is a plant hormone which plays a crucial role in the plant defense against various pathogens and abiotic stresses. Increasing reports suggest that this phenolic compound and its derivatives, collectively termed salicylates, not only regulate plant defense but also have beneficial effects on human health. Both natural and synthetic salicylates are known to have multiple targets in humans, thereby exhibiting various appreciating pharmacological roles, including anti-inflammatory, anticancer, neuroprotective, antidiabetic effects, and so on. The role of some salicylates, such as acetylsalicylic acid (aspirin), 5-aminosalicylic acid (mesalazine), and amorfrutins in human diseases has been well studied in vitro. However, their clinical significance in different diseases is largely unknown. Based on recent studies, five natural salicylates, including amorfrutin, ginkgolic acid, grifolic acid, tetrahydrocannabinolic acid, and cannabidiolic acid, showed potential roles in different challenging human diseases. This review summarizes together some of the recent information on multitarget regulatory activities of these natural salicylates and their pharmacological roles in human health.

Ginkgolic Acids Impair Mitochondrial Function by Decreasing Mitochondrial Biogenesis and Promoting FUNDC1-Dependent Mitophagy

Ginkgolic acids (GAs) are found in the leaves, nuts, and testa of Ginkgo biloba and have been reported to exhibit antitumor, antibacterial, and pro-apoptotic activities. However, their role in mitochondrial function is still unclear. Our previous study showed that genes related to the mitochondria present significant changes in GA-treated mouse bone marrow stromal cells. We hypothesize that GAs may regulate mitochondrial function. Here, we found that GA treatment induced mitochondrial fragmentation, reduced mtDNA copy numbers and mitochondrial protein levels, and impaired mitochondrial adenosine 5'-triphosphate production and oxygen consumption. The GA-induced mitochondrial mass loss may be due to decreased mitochondrial biogenesis. In addition, abolishing autophagy by Atg7 knockout or the administration of an autophagy inhibitor can restore the GA-induced decrease in mitochondrial mass. Furthermore, FUNDC1 knockdown restored the GA-induced changes in mitochondrial mass reduction and mitochondrial membrane potential loss. Together, our studies demonstrated that GAs impaired mitochondrial function by decreasing mitochondrial biogenesis and promoting FUNDC1-dependent mitophagy.

Marsdenia tenacissima extract induces apoptosis and suppresses autophagy through ERK activation in lung cancer cells

BACKGROUND

Marsdenia tenacissima is an herb medicine which has been utilized to treat malignant diseases for decades. The M. tenacissima extract (MTE) shows significant anti-proliferation activity against non-small cell lung cancer (NSCLC) cells, but the underlying mechanisms remain unclear. In this study, we explored the potential anti-proliferation mechanisms of MTE in NSCLC cells in relation to apoptosis as well as autophagy, which are two critical forms to control cancer cell survival and death.

METHODS

The proliferation of H1975 and A549 cells was evaluated by MTT assay. Cell apoptosis was assessed by Annexin V and PI staining, Caspase 3 expression and activity. Autophagy flux proteins were detected by Western blot with or without autophagy inducer and inhibitor. Endogenous LC3-II puncta and LysoTracker staining were monitored by confocal microscopy. The formation of autophagic vacuoles was measured by acridine orange staining. ERK is a crucial molecule to interplay with cell autophagy and apoptosis. The role of ERK on cell apoptosis and autophagy influenced by MTE was determined in the presence of MEK/ERK inhibitor U0126.

RESULTS

The significant growth inhibition and apoptosis induction were observed in MTE treated NSCLC cells. MTE induced cell apoptosis coexisted with elevated Caspase 3 activity. MTE also impaired autophagic flux by upregulated LC3-II and p62 expression. Autophagy inducer EBSS could not abolish the impaired autophagic flux by MTE, while it was augmented in the presence of autophagy inhibitor Baf A1. The autophagosome-lysosome fusion was blocked by MTE via affecting lysosome function as evidenced by decreased expression of LAMP1 and Cathepsin B. The molecule ERK became hyperactivated after MTE treatment, but the MEK/ERK inhibitor U0126 abrogated autophagy inhibition and apoptosis induction caused by MTE, suggested that ERK signaling pathways partially contributed to cell death caused by MTE.

CONCLUSION

Our results demonstrate that MTE caused apoptosis induction as well as autophagy inhibition in NSCLC cells. The activated ERK is partially associated with NSCLC apoptotic and autophagic cell death in response to MTE treatment. The present findings reveal new mechanisms for the anti-tumor activity of MTE against NSCLC.