Anticancer mechanisms on pyroptosis induced by Oridonin: New potential targeted therapeutic strategies.

Pyroptosis is a type of inflammatory cell death that is triggered by the formation of pores on the cell membrane by gasdermin (GSDM) family proteins. This process activates inflammasomes and leads to the maturation and release of proinflammatory cytokines such as interleukin-1ß (IL-1ß) and interleukin-18 (IL-18). Pyroptosis, a form of programmed cell death, has been found to be associated with various biomolecules such as caspases, granzymes, non-coding RNA (lncRNA), reactive oxygen species (ROS), and NOD-like receptor protein 3 (NLRP3). These biomolecules have been shown to play a dual role in cancer by affecting cell proliferation, metastasis, and the tumor microenvironment (TME), resulting in both tumor promotion and anti-tumor effects. Recent studies have found that Oridonin (Ori) has anti-tumor effects by regulating pyroptosis through various pathways. Ori can inhibit pyroptosis by inhibiting caspase-1, which is responsible for activating pyroptosis of the canonical pathway. Additionally, Ori can inhibit pyroptosis by inhibiting NLRP3, which is responsible for activating pyroptosis of the noncanonical pathway. Interestingly, Ori can also activate pyroptosis by activating caspase-3 and caspase-8, which are responsible for activating pyroptosis of the emerging pathway; Ori has been found to be effective in inhibiting pyroptosis by blocking the action of perforin, which is responsible for facilitating the entry of granzyme into cells and activating pyroptosis. Additionally, Ori plays a crucial role in regulating pyroptosis by promoting the accumulation of ROS while inhibiting the ncRNA and NLRP3 pathways. It is worth noting that all of these pathways ultimately regulate pyroptosis by influencing the cleavage of GSDM, which is a key factor in the process. These studies concludes that Ori has extensive anti-cancer effects that are related to its potential regulatory function on pyroptosis. The paper summarizes several potential ways in which Ori participates in the regulation of pyroptosis, providing a reference for further study on the relationship between Ori, pyroptosis, and cancer.

Molecular biological mechanism of action in cancer therapies: Juglone and its derivatives, the future of development.

Juglone (5 - hydroxy - 1, 4 - naphthalene diketone) is a kind of natural naphthoquinone, present in the roots, leaves, nut-hulls, bark and wood of walnut trees. Recent studies have found that Juglone has special significance in the treatment of cancer, which plays a significant role in the resistance of cancer cell proliferation, induction of cancer cell apoptosis, induction of autophagy, anti-angiogenesis and inhibition of cancer cell migration and invasion, etc. Additionally, its derivatives also play a tumor suppressive effect. In conclusion, Juglone and its derivatives have been identified as effective anticancer drugs. This paper reviews action mechanisms of Juglone and its derivatives in cancer treatment.

Anticancer activity of oleanolic acid and its derivatives: Recent advances in evidence, target profiling and mechanisms of action.

Oleanolic acid (OA, 3 ß - hydroxyoleanolic acid-12-en-28-oic acid) is a pentacyclic triterpenoid present in many plants. As a new framework for development of semi synthetic triterpenoids, OA is of great significance in the discovery of anticancer drugs. Some of these derivatives, such as CDDO (2-cyano-3,12-dioxooleana-1, 9 (11)-dien-28-oic acid) have been verified in clinical trials, while other derivatives studied previously, such as SZC014, SZC015 and SZC017 (OA derivatives respectively), are also candidate drugs for cancer treatment. This paper reviews the preclinical studies, literature evidence, target analysis and anticancer mechanism of OA and its derivatives. The mechanism of action of its derivatives mainly includes anti-cancer cell proliferation, inducing tumor cell apoptosis, inducing autophagy, regulating cell cycle regulatory proteins, inhibiting vascular endothelial growth, anti angiogenesis, inhibiting tumor cell migration and invasion. In recent years, the molecular mechanism of OA and its derivatives has been elucidated. These effects seem to be mediated by the alterations in a variety of signaling pathways induced by OA and its derivatives. In conclusion, OA and its derivatives are considered as important candidate drugs for the treatment of cancer, indicating that OA and its derivatives have the potential to be used as anticancer drugs in practice.

Synthesis and antitumor activity of α,ß-unsaturated carbonyl moiety- containing oleanolic acid derivatives targeting PI3K/AKT/mTOR signaling pathway.

Oleanolic acid (OA) and its semi-synthetic derivatives have been reported to have a wide range of biological activities. The introduction of electrophilic Michael acceptor group can increase the reactivity of OA to cellular targets and thus improve the anti-tumor activity. In this work, a series of novel α,ß-unsaturated carbonyl derivatives of OA were designed and synthesized. Their in vitro cytotoxic activity against MCF-7, HepG2 and HeLa cells were tested. Most derivatives exhibited improved cell growth inhibitory activity, especially for 3d with an IC50 of 0.77 µM in MCF-7 cells. Moreover, 3d inhibited the migration of MCF-7 and HeLa cells at the concentration of 4 µM. Flow cytometric analysis revealed that 3d induced cell apoptosis and S phase arrest in a concentration-dependent manner. Western blotting experiment demonstrated that 3d inhibited the phosphorylation of AKT and mTOR. These results suggest that this series of OA derivatives bearing exocyclic methylene ketone pharmacophore are promising anticancer agents as potential PI3K/AKT/mTOR pathway inhibitors.

Geniposide ameliorates TNBS-induced experimental colitis in rats via reducing inflammatory cytokine release and restoring impaired intestinal barrier function.

Geniposide is an iridoid glycosides purified from the fruit of Gardenia jasminoides Ellis, which is known to have antiinflammatory, anti-oxidative and anti-tumor activities. The present study aimed to investigate the effects of geniposide on experimental rat colitis and to reveal the related mechanisms. Experimental rat colitis was induced by rectal administration of a TNBS solution. The rats were treated with geniposide (25, 50 mg·kg-1·d-1, ig) or with sulfasalazine (SASP, 100 mg·kg-1·d-1, ig) as positive control for 14 consecutive days. A Caco-2 cell monolayer exposed to lipopolysaccharides (LPS) was used as an epithelial barrier dysfunction model. Transepithelial electrical resistance (TER) was measured to evaluate intestinal barrier function. In rats with TNBS-induced colitis, administration of geniposide or SASP significantly increased the TNBS-decreased body weight and ameliorated TNBS-induced experimental colitis and related symptoms. Geniposide or SASP suppressed inflammatory cytokine (TNF-α, IL-1ß, and IL-6) release and neutrophil infiltration (myeloperoxidase activity) in the colon. In Caco-2 cells, geniposide (25-100 µg/mL) ameliorated LPS-induced endothelial barrier dysfunction via dose-dependently increasing transepithelial electrical resistance (TER). The results from both in vivo and in vitro studies revealed that geniposide down-regulated NF-κB, COX-2, iNOS and MLCK protein expression, up-regulated the expression of tight junction proteins (occludin and ZO-1), and facilitated AMPK phosphorylation. Both AMPK siRNA transfection and AMPK overexpression abrogated the geniposide-reduced MLCK protein expression, suggesting that geniposide ameliorated barrier dysfunction via AMPK-mediated inhibition of the MLCK pathway. In conclusion, geniposide ameliorated TNBS-induced experimental rat colitis by both reducing inflammation and modulating the disrupted epithelial barrier function via activating the AMPK signaling pathway.

Inhibitory effect of potassium alum on smooth muscle contraction of rabbit and its mechanism.

OBJECTIVE: To investigate the effects of potassium alum (Alunite) on smooth muscle contraction and phosphorylation of myosin light chain by myosin light chain kinase (MLCK) and to try to find out the clue of its mechanism. METHODS: An isolated rabbit duodenum smooth muscle strip was selected to study the effects of potassium alum on its contractile activity under the condition of Krebs' solution using HW-400S constant temperature smooth muscle trough. The myosin and MLCK were purified from chicken gizzard smooth muscle. Myosin light chain phosphorylation was determined by glycerol-polyacrylamide gel electrophoresis; myosin Mg2+-ATPase activity was measured by inorganic phosphate liberation method. RESULTS: Potassium alum (2.5-20 mmol/L) inhibited the contraction on duodenum in a dose-related and a time-dependent manner; potassium alum could also inhibit the extent of phosphorylation of myosin light chain in a dose-related and a time-dependent manner; and potassium alum inhibited the extent of Mg2+-ATPase activity in a dose-related manner. CONCLUSIONS: Potassium alum inhibited smooth muscle contraction in a way of inhibiting phosphorylation of myosin light chain and Mg2+-ATPase activity. This has revealed the molecular mechanism of treatment of gastrointestinal spastic disorders by potassium alum.

Research progress of ursolic acid's anti-tumor actions.

Ursolic acid (UA) is a sort of pentacyclic triterpenoid carboxylic acid purified from natural plant. UA has a series of biological effects such as sedative, anti-inflammatory, anti-bacterial, anti-diabetic, antiulcer, etc. It is discovered that UA has a broad-spectrum anti-tumor effect in recent years, which has attracted more and more scholars' attention. This review explained anti-tumor actions of UA, including (1) the protection of cells' DNA from different damages; (2) the anti-tumor cell proliferation by the inhibition of epidermal growth factor receptor/mitogen-activated protein kinase signal or of FoxM1 transcription factors, respectively; (3) antiangiogenesis, (4) the immunological surveillance to tumors; (5) the inhibition of tumor cell migration and invasion; (6) the effect of UA on caspase, cytochromes C, nuclear factor kappa B, cyclooxygenase, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) or mammalian target of rapamycin signal to induce tumor cell apoptosis respectively, and etc. Moreover, UA has selective toxicity to tumor cells, basically no effect on normal cells. With further studies, UA would be one of the potential anti-tumor agents.

Research progress of warfarin-associated vascular calcification and its possible therapy.

Vascular calcification is a common comorbidity in elderly patients with diabetes mellitus or renal insufficiency. A large number of studies have shown that vascular calcification can be induced and accelerated in patients undergoing long-term treatment with warfarin, leading to some severe complications, such as hypertension, atherosclerosis, valvular calcification, and coronary calcification, especially in the population with atrial fibrillation, hemodialysis, and chronic kidney disease. Warfarin inhibits the activation of vitamin K-dependent coagulation factors and affects the function of vitamin K-dependent proteins via interference of the vitamin K cycle by antagonizing vitamin K. One of its consequences is adverse effects on the expression and function of matrix Gla protein, one of the important vitamin K-dependent proteins. Matrix Gla protein acts as an inhibitor of vascular calcification by blocking bone morphogenetic protein signaling or promoting the phagocytosis of apoptotic bodies; moreover, it restrains the formation of calcification directly resulting in the promotion of vascular calcification. This article also discusses the various treatments for vascular calcification caused by warfarin.

Effects of berberine on rat jejunal motility.

OBJECTIVES: The aim of the study was to evaluate berberine-induced bidirectional regulation on the contractility of jejunum. METHODS: Different low and high contractile states of isolated jejunal segment from rat were established to investigate the effects of berberine. KEY FINDINGS: Stimulatory effects on jejunal segment were exerted by berberine in six low contractile states and inhibitory effects were produced on jejunal segment in six high contractile states. The effects of berberine on myosin light chain kinase (MLCK) mRNA expression, MLCK protein content, and myosin phosphorylation in jejunum were also bidirectional. Bidirectional regulation was not observed in the presence of tetrodotoxin. No regulatory effects of berberine on jejunal contractility were observed in the presence of verapamil. The stimulatory effects of berberine on jejunal contractility were blocked by atropine. The inhibitory effects of berberine on jejunal contractility were abolished by phentolamine, propranolol and L-NG-nitro-arginine, respectively. CONCLUSIONS: Berberine-induced bidirectional regulation needed the presence of the enteric nervous system, and depended on the influx of extracellular Ca(2+) , related to the cholinergic system while jejunum was in low contractile states, and related to the adrenergic system and nitric oxide relaxing mechanism while jejunum was in high contractile states. The results suggested the potential clinical implication of berberine for alternating-type irritable bowel syndrome.

Characteristics of deslanoside-induced modulation on jejunal contractility.

AIM: To characterize the dual effects of deslanoside on the contractility of jejunal smooth muscle. METHODS: Eight pairs of different low and high contractile states of isolated jejunal smooth muscle fragment (JSMF) were established. Contractile amplitude of JSMF in different low and high contractile states was selected to determine the effects of deslanoside, and Western blotting analysis was performed to measure the effects of deslanoside on myosin phosphorylation of jejunal smooth muscle. RESULTS: Stimulatory effects on the contractility of JSMF were induced (45.3% ± 4.0% vs 87.0% ± 7.8%, P < 0.01) by deslanoside in 8 low contractile states, and inhibitory effects were induced (180.6% ± 17.8% vs 109.9% ± 10.8%, P < 0.01) on the contractility of JSMF in 8 high contractile states. The effect of deslanoside on the phosphorylation of myosin light chain of JSMF in low (78.1% ± 4.1% vs 96.0% ± 8.1%, P < 0.01) and high contractile state (139.2% ± 8.5% vs 105.5 ± 7.34, P < 0.01) was also bidirectional. Bidirectional regulation (BR) was abolished in the presence of tetrodotoxin. Deslanoside did not affect jejunal contractility pretreated with the Ca(2+) channel blocker verapamil or in a Ca(2+)-free assay condition. The stimulatory effect of deslanoside on JSMF in a low contractile state (low Ca(2+) induced) was abolished by atropine. The inhibitory effect of deslanoside on jejunal contractility in a high contractile state (high Ca(2+) induced) was blocked by phentolamine, propranolol and L-NG-nitro-arginine, respectively. CONCLUSION: Deslanoside-induced BR is Ca(2+) dependent and is related to cholinergic and adrenergic systems when JSMF is in low or high contractile states.

Interaction between myosin and a trace amount of caldesmon.

Caldesmon (CaD) is known as an actin binding protein. In this study, we proposed that a trace amount of caldesmon (TACD) could highly, efficiently, interact with myosin by producing a 'domino-like cascade' and characterized that TACD (lowest caldesmon/myosin molar ratio: 1/10,000) significantly increased precipitations and intrinsic tryptophan fluorescence intensity of myosin in both phosphorylated and unphosphorylated states compared to the base controls (P < 0.01). Actin-blocked TACD-myosin interaction, suggesting that it functioned as a negative regulator. Since CaD is not an enzyme, the in vivo significance of the highly efficient TACD-myosin interaction needs further investigation.

Bi-directional regulation of emodin and quercetin on smooth muscle myosin of gizzard.

This study is to reveal the characteristics of bidirectional regulation of emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) and quercetin on gizzard smooth muscle myosin. Our results indicate that: (a) emodin demonstrates stimulatory effects, and quercetin produces inhibitory effects on myosin phosphorylation and Mg(2+)-ATPase activities of Ca(2+)/calmodulin-dependent phosphorylated myosin in a dose-dependent manner; (b) a combination of emodin and quercetin enhances phosphorylation and Mg(2+)-ATPase activities for partially phosphorylated myosin and inhibits those activities for fully phosphorylated myosin; (c) 1-(5-Chloronaphthalene-1-sulfonyl)-1H2-hexahydro-1,4-diazepine inhibits myosin phosphorylation in the presence of emodin and/or quercetin. A combination of emodin and quercetin indicates its potential for modulating gastric-intestinal smooth muscle.

The influence of trace amount of calponin on the smooth muscle myosins in different states.

Calponin (CaP), a thin filament-associated protein, plays an important role in the regulation of smooth muscle contractility. It has been known that CaP inhibits the actin-activated myosin MgATPase activity via binding to F-actin, and stimulates myosin MgATPase activity via binding to myosin. Our recent study revealed a new phenomenon that trace amount of CaP (TAC) could influence the function of different states of myosin. Our data showed that in the absence of actin, CaP, even in the concentration of 0.0001 microM, significantly increased the precipitations of 1 microM unphosphorylated myosin, Ca(2+)-CaM dependently, and independently phosphorylated myosin by MLCK, and stimulated the MgATPase activities of these myosins slightly but significantly. However, no obvious change of precipitation of myosin phosphorylated by PKA was observed, indicating the relative selective effect of TAC. In the presence of actin, myosin, and TAC, the increase of myosin precipitation was abolished, and no obvious changes of actin precipitations and actin-activated myosin MgATPase activities were observed implicating the highly efficiency of TAC on myosin being present in the absence of actin. Although we cannot give conclusive comments to our results, we propose that the high efficiency of TAC-myosin interaction is present in the regulation of the function of myosin when actin is dissociated from myosin, even if CaP/myosin ratio is very low; this high efficient interaction between TAC and myosin can be abolished by actin. However, why and how TAC can possess such a high efficiency to influence myosin and how the physiological significance of the high efficiency of TAC is in regulating the interaction between myosin and actin remain to be investigated.

Effects of caldesmon, calponin, and tropomyosin on the Mg2+-ATPase activities of smooth muscle myosin.

OBJECTIVE: To test whether in the absence of actin, actin-binding proteins such as caldesmon, calponin, and tropomyosin interact with the myosin of unphosphorylation, Ca2+-dependent phosphorylation (CDP), and Ca2+-independent phosphorylation (CIP) and stimulate myosin Mg2+-ATPase activities. METHODS: Mg2+-ATPase activities were measured to evaluate the effects of caldesmon, calponin, and tropomyosin on the myosin in unphosphorylation, CDP by myosin light chain kinase (MLCK), and CIP by MLCK. RESULTS: (1) At different incubation-time, i.e., 5, 10, 20, 40, and 60 minutes, the highest Mg2+-ATPase activity was observed when myosin was in the state of CDP, the medium was CIP of myosin, and the lowest was the unphosphorylated myosin. (2) In the absence of caldesmon, calponin, and tropomyosin, the Mg2+-ATPase activities from high to low were in the following order: CDP, CIP, and unphosphorylated myosin. However, in the presence of caldesmon, calponin, and tropomyosin, the order of relative value of Mg2+-ATPase activities from high to low was unphosphorylated, CIP, and CDP of myosin respectively compared to the corresponding controls. CONCLUSIONS: The results propose that caldesmon, calponin, and tropomyosin are capable of stimulating Mg2+-ATPase activity of smooth muscle myosin in Ca2+-independent manner, since Ca2+ is not obligating for the stimulating effects of the three proteins. The common characteristic of the three proteins is that when myosin activities are low, their activations are relatively strong and this property might be involved in smooth muscle tension keeping.

The characterization of Ca(2+)-calmodulin independent phosphorylation of myosin light chains by a fragment from myosin light chain kinase.

A constitutively active myosin light chain kinase (MLCK) fragment (MLCKF) was found to phosphorylate myosin light chains (MLC(20)) in a Ca(2+)-CaM independent way more effectively than the intact MLCK. The MLCKF was prepared by tryptic digestion of MLCK. Western blot was used to demonstrate the homogeneity of trypsin-digested MLCKF and intact MLCK. Phosphorylation of MLC(20) was detected by Gly-PAGE and Scoin Image Software, and Mg(2+)-ATPase activity of myosin was measured with spectrophotometry. Our results indicated that Ca(2+)-CaM independent phosphorylation of myosin (CIPM) by MLCKF was more efficient than CIPM by MLCK and less efficient than Ca(2+)-CaM dependent phosphorylation of myosin (CDPM) by MLCK in phosphorylating MLC(20) and stimulating myosin Mg(2+)-ATPase activity; both CIPM by MLCKF and CIPM by MLCK were less influenced by the rise of incubation-temperature, the prolonging of incubation-time, the increase of ionic strength of KCl and less sensitive to MLCK inhibitor ML-9 1-(5-chloronaphthalene-1-sulfonyl) -1H-hexahydro-1,4-diazepine than CDPM by MLCK. The differences were statistically significant ((P)<0.01, or (P)<0.05). The results may be valuable to further investigating the mechanisms of sustained tension characterized by less energy consumption.