Dioscin Promotes Prostate Cancer Cell Apoptosis and Inhibits Cell Invasion by Increasing SHP1 Phosphorylation and Suppressing the Subsequent MAPK Signaling Pathway

Asiatic acid exhibits antimetastatic activity in human prostate cancer cells by modulating the MZF-1/Elk-1/Snail signaling axis

Prostate cancer metastasis is associated with poor prognosis and is difficult to treat clinically. Numerous studies have shown that Asiatic Acid (AA) has antibacterial, anti-inflammatory, and antioxidant effects. However, the effect of AA on prostate cancer metastasis is still unclear. This purpose of this study is to investigate the effect of AA on prostate cancer metastasis and to better understand its molecular mechanisms of action. Our results indicate that AA ≤ 30 μM did not influence cell viability and cell cycle distribution in PC3, 22Rv1 and DU145 cells. AA inhibited the migratory and invasive capabilities of three prostate cancer cells to be due to its effects on Snail, but did not have activity on Slug. We observed that AA inhibited the Myeloid zinc finger 1 (MZF-1) and ETS Like-1 (Elk-1) protein interaction and affected the complex's binding capacity to the Snail promoter region, ultimately blocking Snail transcription activity. Kinase cascade analysis revealed that phosphorylation of MEK3/6 and p38MAPK was inhibited by AA treatment. Moreover, knockdown of p38MAPK enhanced AA-suppressed protein levels of MZF-1, Elk-1, and Snail, suggesting that p38MAPK influences prostate cancer cell metastasis. These results provide promise for AA as a future candidate in the development of drug therapies to prevent or treat prostate cancer metastasis.

Synthesis and Biological Evaluation of 3-Amino-4,4-Dimethyl Lithocholic Acid Derivatives as Novel, Selective, and Cellularly Active Allosteric SHP1 Activators

Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP1), a non-receptor member of the protein tyrosine phosphatase (PTP) family, negatively regulates several signaling pathways that are responsible for pathological cell processes in cancers. In this study, we report a series of 3-amino-4,4-dimethyl lithocholic acid derivatives as SHP1 activators. The most potent compounds, 5az-ba, showed low micromolar activating effects (EC50: 1.54–2.10 μM) for SHP1, with 7.63–8.79-fold maximum activation and significant selectivity over the closest homologue Src homology 2 domain-containing protein tyrosine phosphatase 2 (SHP2) (>32-fold). 5az-ba showed potent anti-tumor effects with IC50 values of 1.65–5.51 μM against leukemia and lung cancer cells. A new allosteric mechanism of SHP1 activation, whereby small molecules bind to a central allosteric pocket and stabilize the active conformation of SHP1, was proposed. The activation mechanism was consistent with the structure–activity relationship (SAR) data. This study demonstrates that 3-amino-4,4-dimethyl lithocholic acid derivatives can be selective SHP1 activators with potent cellular efficacy.

Integrated miRNA and mRNA omics reveal dioscin suppresses migration and invasion via MEK/ERK and JNK signaling pathways in human endometrial carcinoma in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonatum sibiricum Redouté (PS, also called Huangjing in traditional Chinese medicine), is a perennial herb as homology of medicine and food. According to the traditional Chinese medicine theory "Special Records of Famous Doctors", its functions include invigorating qi and nourishing yin, tonifying spleen and kidney. Traditionally, qi and blood therapy has been believed as most applicable to the treatment of uterine disease. The current research has focused on the effect and mechanism of dioscin, the main active component of PS, on Endometrial carcinoma (EC).

AIM OF THE STUDY

To study the efficacy of dioscin on proliferation and migration of Endometrial carcinoma cell line, we conducted experiments by using xenograft model and Ishikawa cells, and explored the potential molecular mechanism.

MATERIALS AND METHODS

mRNA and miRNA omics techniques were employed to investigate the regulatory mechanism of dioscin on EC Ishikawa cells. Based on in vivo and in vitro experiments, cell clone formation, cell scratching, Transwell, H&E staining, immunohistochemistry, q-PCR, and Western blot techniques were used to determine the molecular effects and mechanisms of dioscin on cell migration.

RESULTS

Integrated miRNA and mRNA omics data showed that 513 significantly different genes marked enrichment in MAPK signaling pathway. The in vivo data showed that dioscin (24 mg/kg) significantly inhibited tumor growth. The in vitro proliferation and invasiveness of dioscin on Ishikawa cells showed that dioscin could significantly decrease the colony numbers, and suppress the Ishikawa cell wound healing, migration and invasion. Molecular data revealed that dioscin decreased the MMP2 and MMP9 expression in vitro and in vivo. The p-MEK, p-ERK, and p-JNK expression levels were also confirmed to be significantly reduced. Key regulators in the MAPK signaling pathway were further validated in xenograft tumors.

CONCLUSION

Our data indicated that dioscin inhibited Ishikawa cell migration and invasion mediated through MEK/ERK and JNK signaling. More importantly, screened hub miRNAs and genes can be regarded as potential molecular targets for future EC treatment.

Dioscin ameliorates silica-aggravated systemic lupus erythematosus via suppressing apoptosis and improving LC3-associated phagocytosis in MRL/lpr mice

Inhalation of silica not only directly leads to silicosis locally, but also results in various types of autoimmune diseases systemically, most commonly systemic lupus erythematosus (SLE). Little is known about the etiopathogenesis of silica-aggravated SLE to date, however, abnormal apoptosis and impaired apoptotic clearance have been reported to be closely related to the occurrence of SLE. LC3-associated phagocytosis (LAP) is a non-canonical form of autophagy, which plays a crucial role in mediating the clearance of apoptotic cells. Here we showed that the excessive accumulation of apoptotic debris in MRL/lpr mice exposed to silica might be due to the increased cell apoptosis and defective LAP caused by silica, thus accelerating the occurrence and progression of silica-aggravated SLE. Dioscin is an active ingredient in the family of Dioscoreaceae and is reported to possess multiple pharmacological activities, including anti-inflammatory, anti-apoptotic and autophagy-promoting properties. However, its role in SLE aggravated by silica exposure has not been investigated. In our study, we confirmed that dioscin decreased the accumulation of apoptotic debris by suppressing the excessive cell apoptosis and improving the LAP of immune cells in lung and spleen, leading to subsequent dramatically ameliorated lupus-like symptoms in silica-exposed MRL/lpr mice.

Yamogenin-Induced Cell Cycle Arrest, Oxidative Stress, and Apoptosis in Human Ovarian Cancer Cell Line

Steroidal saponins are a group of compounds with complex structures and biological activities. They have anti-inflammatory, antimicrobial, fungicidal, and antitumor properties. Yamogenin is one of the spirostane saponins and occurs in Trigonella foenum-graecum, Asparagus officinalis, and Dioscorea collettii. It is a stereoisomer of diosgenin-a well-known compound whose activity and mechanisms of action in cancer cells are determined. However, the antitumor effect of yamogenin is still little known, and the mechanism of action has not been determined. In this study, we evaluated the effect of yamogenin on human ovarian cancer SKOV-3 cells in vitro by determining the cellular factors that trigger cell death. The viability of the cells was assessed with a Real-Time xCELLigence system and the cell cycle arrest with flow cytometry. The activity of initiator and executioner caspases (-8, -9, and -3/7) was estimated with luminometry and flow cytometry, respectively. The mitochondrial membrane depolarization, the level of oxidative stress, and DNA damage in the yamogenin-treated cells were also evaluated by flow cytometry. Genes expression analysis at the mRNA level was conducted with Real-Time PCR. Bid activation and chromatin condensation were estimated with fluorescent microscopy. The obtained results indicate that yamogenin has cytotoxic activity in SKOV-3 cells with an IC₅₀ value of 23.90 ± 1.48 µg/mL and strongly inhibits the cell cycle in the sub-G1 phase. The compound also triggers cell death with a significant decrease in mitochondrial membrane potential, an increase in the level of oxidative stress (over two times higher in comparison to the control), and activation of caspase-8, -9, -3/7, as well as Bid. The results of genes expression indicate that the Tumor Necrosis Factor (TNF) Receptor Superfamily Members (TNF, TNFRSF10, TNFRSF10B, TNFRSF1B, and TNFRSF25), Fas Associated via Death Domain (FADD), and Death Effector Domain Containing 2 (DEDD2) were significantly upregulated and their relative expression was at least two times higher than in the control. Our work shows that yamogenin induces apoptosis in ovarian cancer cells, and both the extrinsic and mitochondrial-intrinsic pathways are involved in this process.

Inhibitors and Activators of the p38 Mitogen- Activated MAP Kinase (MAPK) Family as Drugs to Treat Cancer and Inflammation

The p38 MAP kinases are a sub-family of the broad group of mitogen-activated serine-threonine protein kinases. The best-characterised, most widely expressed, and most targeted by drugs is p38α MAP kinase. This review briefly summarises the place of p38α MAP kinase in cellular signalling and discusses the structures and activity profiles of representative examples of the major classes of inhibitors and activators (both synthetic compounds and natural products) of this enzyme. Primary screening was primarily direct in vitro inhibition of isolated p38α enzyme.

Dioscin: A review on pharmacological properties and therapeutic values

Dioscin has gained immense popularity as a natural, bioactive steroid saponin, which offers numerous medical benefits. The growing global incidence of disease-associated morbidity and mortality continues to compromise human health, facilitating an increasingly urgent need for nontoxic, noninvasive, and efficient treatment alternatives. Natural compounds can contribute vastly to this field. Over recent years, studies have demonstrated the remarkable protective actions of dioscin against a variety of human malignancies, metabolic disorders, organ injuries, and viral/fungal infections. The successful usage of this phytocompound has been widely seen in medical treatment procedures under traditional Chinese medicine, and it is becoming progressively prevalent worldwide. This review provides an insight into the wide spectrum of pharmacological activities of dioscin, as reported and compiled in recent literature. The various novel approaches and applications of dioscin also verify the advantages exhibited by plant extracts against commercially available drugs, highlighting the potential of phytochemical agents like dioscin to be further incorporated into clinical practice.

In Silico Screening and In Vitro Assessment of Natural Products with Anti-Virulence Activity against Helicobacter pylori

Helicobacter pylori is one of the most frequent human pathogens and a leading etiological agent of various gastric diseases. As stringent response, coordinated by a SpoT protein, seems to be crucial for the survivability of H. pylori, the main goal of this article was to use in silico computational studies to find phytochemical compounds capable of binding to the active site of SpoT from H. pylori and confirm the ability of the most active candidates to interfere with the virulence of this bacterium through in vitro experiments. From 791 natural substances submitted for the virtual screening procedure, 10 were chosen and followed for further in vitro examinations. Among these, dioscin showed the most interesting parameters (the lowest MIC, the highest anti-biofilm activity in static conditions, and a relatively low stimulation of morphological transition into coccoids). Therefore, in the last part, we extended the research with a number of further experiments and observed the ability of dioscin to significantly reduce the formation of H. pylori biofilm under Bioflux-generated flow conditions and its capacity for additive enhancement of the antibacterial activity of all three commonly used antibiotics (clarithromycin, metronidazole, and levofloxacin). Based on these results, we suggest that dioscin may be an interesting candidate for new therapies targeting H. pylori survivability and virulence.

Dioscin induces ferroptosis and synergistic cytotoxicity with chemotherapeutics in melanoma cells

In this study, we evaluated the anti-tumor effects of dioscin, a steroidal saponin, on melanoma cells. Dioscin significantly inhibited cell viability and induced cell death of melanoma cells in a time- and dose- dependent manner. Furthermore, dioscin increased the concentration of intracellular ferrous irons, MDA and ROS. This effect could be inhibited by L-g-glutamyl-p-nitroanilide (GPNA), compound 968 and ferroptosis inhibitor ferrostatin-1 (Fer-1). Furthermore, dioscin induced ferroptosis by affecting the expression of transferrin and ferroportin which are regulators of intracellular levels of iron. Finally, dioscin in combination with various chemotherapeutic agents showed synergistic effects against melanoma cells. Our data suggested that dioscin exerted anti-tumor effects in melanoma cells by inducing ferroptosis. Dioscin alone or with other agents might be applied as a promising strategy to treat melanoma.

Dioscin inhibits human endometrial carcinoma proliferation via G0/G1 cell cycle arrest and mitochondrial-dependent signaling pathway

The present study emphasized on the anti-cancerous effects of dioscin and its underlying molecular mechanism in human endometrial cancer Ishikawa cells. Dioscin significantly suppressed the proliferation of Ishikawa cells at IC₅₀ of 2.37 μM. Besides, dioscin could inhibit the proliferation of Ishikawa cells by blocking the G0/G1 cell cycle through up-regulation of p16, p21, and p27 and down-regulation of cycle-cellular protein (Cyclin A/D/E) and cyclin-dependent kinase (CDK2/4/6). Also, it promoted apoptosis through the mitochondrial pathway, including the regulation of Bcl family proteins, the increase of ROS levels, the activation of caspases (Caspase 9/3), and the decrease of mitochondrial membrane permeability. Whereas dioscin also effectively activated the marker genes and proteins (Fas, TNF-R1, and Caspase 8) related to the death receptor-mediated pathway which confirmed the involvement of both the pathways for dioscin-induced apoptosis. The current results demonstrated that dioscin possessed potential health benefits with respect to endometrial cancer prevention and treatment.