Diosmetin inhibits cell proliferation and induces apoptosis by regulating autophagy via the mammalian target of rapamycin pathway in hepatocellular carcinoma HepG2 cells

Diosmetin: A dietary flavone as modulator of signaling pathways in cancer progression

Flavonoids, constituting the most extensive category of polyphenols, founds in a variety of plants and comprise over 9000 compounds. Diosmetin, O-methylated flavone (3',5,7-trihydroxy-4'-methoxyflavone) of flavonoid aglycone diosmin have witnessed a significant surge in recent years. Many studies showed that flavonoids induced cytotoxicity in different organ specific cancer types. Thus, current review evaluates the anticancer potential of diosmetin and shed light on its mechanism of action such as cell cycle regulation, apoptosis via both intrinsic and extrinsic pathway, autophagy and tumour progression and metastasis. It also provides comprehensive analysis of different cancer targets and their role in breast, colon, hepatic, gliomas, leukemia, lung, prostate and skin cancer. Combination studies of diosmetin to improve drug sensitivity and reduce toxicity towards normal cells has been also discussed. Besides, in vitro studies, present review also discuss the anticancer potential of diosmetin on xenograft mice model. Different natural sources of diosmetin, limitations, pharmacokinetic analysis and toxicity study also summarized in current review. The emphasis on enhancing solubility and permeability for clinical utility has been thoroughly highlighted with particular attention given to the utilization of nano formulations to overcome existing barriers. At last, in-depth analysis of current challenges and a forward-looking perspective deliberated to address the existing gaps and position it as a promising lead compound for clinical applications in cancer treatment. This discussion is boosted by diosmetin's potential anticancer properties on different cancers, makes valuable candidates in the ongoing quest for effective therapeutic interventions against cancer.

Critical roles of lncRNA-mediated autophagy in urologic malignancies

Urologic oncology is a significant public health concern on a global scale. Recent research indicates that long chain non-coding RNAs (lncRNAs) and autophagy play crucial roles in various cancers, including urologic malignancies. This article provides a summary of the latest research findings, suggesting that lncRNA-mediated autophagy could either suppress or promote tumors in prostate, kidney, and bladder cancers. The intricate network involving different lncRNAs, target genes, and mediated signaling pathways plays a crucial role in urological malignancies by modulating the autophagic process. Dysregulated expression of lncRNAs can disrupt autophagy, leading to tumorigenesis, progression, and enhanced resistance to therapy. Consequently, targeting particular lncRNAs that control autophagy could serve as a dependable diagnostic tool and a promising prognostic biomarker in urologic oncology, while also holding potential as an effective therapeutic approach.

Rosuvastatin and diosmetin inhibited the HSP70/TLR4 /NF-κB p65/NLRP3 signaling pathways and switched macrophage to M2 phenotype in a rat model of acute kidney injury induced by cisplatin

Numerous efforts to manage acute kidney injury (AKI) were unsuccessful because its pathophysiology is still poorly understood. Thus, our research hotspot was to explore the possible renoprotective effects of rosuvastatin (Ros) and diosmetin (D) on macrophage polarization and the role of HSP70/TLR4/MyD88/NF-κB p65/NLRP3/STAT3 signaling in cis-induced AKI and study the activity of D against uropathogenic bacteria. Fifty-four albino male rats were randomized into 9 groups equally: Control, Ros, D20, D40, untreated Cis, and Cis groups cotreated with Ros, D20, D40 and Ros+D40 for 10 days. Our results indicated that Ros and D, in a dose-dependent manner, markedly restored body weight, systolic blood pressure, and renal histological architecture besides significantly upregulated SOD levels, expression of anti-inflammatory CD163 macrophages, arginase1levels, IL-10 levels,STAT3 and PCNA immunoreactivity. Also, they significantly downregulated renal index, serum urea, serum creatinine, serum cystatin c, inflammatory biomarkers (C reactive protein, IL1β & TNF-α), MDA levels, HSP70/TLR4/MyD88/NF-κB p65/NLRP3 expressions, proinflammatory CD68 macrophages and caspase-3 immunoreactivity, resulting in a reversal of cis-induced renal damage. These findings were further confirmed by molecular docking that showed the binding affinity of Ros and D towards TLR4 and NLRP3. Furthermore, D had antibacterial action with a minimum inhibitory concentration ranging from 128 to 256 µg/mL and caused a delay in the growth of the tested isolates, and negatively affected the membrane integrity. In conclusion, Ros and D had antioxidant, anti-inflammatory and antiapoptotic properties and switched macrophage from proinflammatory CD68 to anti-inflammatory CD163. Additionally, the targeting of HSP70/TLR4/MyD88/NF-κB p65/NLRP3/STAT3 signals are effective therapeutic strategy in AKI.

Therapeutic potential of natural products in inflammation: underlying molecular mechanisms, clinical outcomes, technological advances, and future perspectives

Chronic inflammation is a common underlying factor in many major diseases, including heart disease, diabetes, cancer, and autoimmune disorders, and is responsible for up to 60% of all deaths worldwide. Metformin, statins, and corticosteroids, and NSAIDs (non-steroidal anti-inflammatory drugs) are often given as anti-inflammatory pharmaceuticals, however, often have even more debilitating side effects than the illness itself. The natural product-based therapy of inflammation-related diseases has no adverse effects and good beneficial results compared to substitute conventional anti-inflammatory medications. In this review article, we provide a concise overview of present pharmacological treatments, the pathophysiology of inflammation, and the signaling pathways that underlie it. In addition, we focus on the most promising natural products identified as potential anti-inflammatory therapeutic agents. Moreover, preclinical studies and clinical trials evaluating the efficacy of natural products as anti-inflammatory therapeutic agents and their pragmatic applications with promising outcomes are reviewed. In addition, the safety, side effects and technical barriers of natural products are discussed. Furthermore, we also summarized the latest technological advances in the discovery and scientific development of natural products-based medicine.

Crosstalk between xanthine oxidase (XO) inhibiting and cancer chemotherapeutic properties of comestible flavonoids- a comprehensive update

Gout is an inflammatory disease caused by metabolic disorder or genetic inheritance. People throughout the world are strongly dependent on ethnomedicine for the treatment of gout and some receive satisfactory curative treatment. The natural remedies as well as established drugs derived from natural sources or synthetically made exert their action by mechanisms that are closely associated with anticancer treatment mechanisms regarding inhibition of xanthine oxidase, feedback inhibition of de novo purine synthesis, depolymerization and disappearance of microtubule, inhibition of NF-ĸB activation, induction of TRAIL, promotion of apoptosis, and caspase activation and proteasome inhibition. Some anti-gout and anticancer novel compounds interact with same receptors for their action, e.g., colchicine and colchicine analogues. Dietary flavonoids, i.e., chrysin, kaempferol, quercetin, fisetin, pelargonidin, apigenin, luteolin, myricetin, isorhamnetin, phloretinetc etc. have comparable IC₅₀ values with established anti-gout drug and effective against both cancer and gout. Moreover, a noticeable number of newer anticancer compounds have already been isolated from plants that have been using by local traditional healers and herbal practitioners to treat gout. Therefore, the anti-gout plants might have greater potentiality to become selective candidates for screening of newer anticancer leads.

Diosmetin Protects against Cardiac Hypertrophy via p62/Keap1/Nrf2 Signaling Pathway

An important pathophysiological consequence of pressure overload-induced cardiac hypertrophy is adverse cardiac remodeling, including structural changes in cardiomyocytes and extracellular matrix. Diosmetin (DIO), a monomethoxyflavone isolated from citrus fruits, had antioxidative stress effects in multiple organs. The purpose of this study was to examine the biological effect of diosmetin on pathological cardiac hypertrophy. In mice, diosmetin treatment reduced cardiac hypertrophy and dysfunction in an aortic banding- (AB-) induced pressure overload model and reducing myocardial oxidative stress by increasing antioxidant gene expression. In vitro, diosmetin (10 or 50 μm, 12 h or 24 h) protected PE-induced cardiomyocyte hypertrophy in neonatal rat cardiomyocytes. Mechanistically, diosmetin inhibited autophagy by activating the PI3K/Akt pathway. In particular, diosmetin induced the accumulation of p62 and its interaction with Keap1, promoted the nuclear translocation of Nrf2, and increased the expression of antioxidant stress genes in the process of cardiac hypertrophy. Furthermore, knockdown of p62 in rat primary cardiomyocytes abrogate the protective effect of diosmetin on cardiomyocyte hypertrophy. Similarly, the Nrf2 inhibitor ML385 obviously abolished the above effects by diosmetin treatment. In conclusion, our results suggest that diosmetin protects cardiac hypertrophy under pressure overload through the p62/Keap1/Nrf2 signaling pathway, suggesting the potential of diosmetin as a novel therapy for pathological cardiac hypertrophy.

Diosmetin attenuate experimental ulcerative colitis in rats via suppression of NF-κB, TNF-α and IL-6 signalling pathways correlated with down-regulation of apoptotic events

Introduction

Ulcerative colitis (UC) is a chronic inflammation of colon in which the innermost tissue of colon and rectum develops deep-rooted inflammation. Diosmetin is the aglycone of the flavonoid glycoside diosmin, commonly found in citrus fruits. Therapeutically diosmetin is indicated to demonstrate anticancer, antimicrobial, antioxidant, oestrogenic and anti-inflammatory activity.

Methods

In this research, we studied the action of diosmetin on TNBS (2,4,6-trinitrobenzene sulfonic acid)-induced UC in rats. Male Wister rats were anesthetised with pentobarbital and TNBS introduced by performing an enema. Diosmetin treatment was provided through oral gavage for the next 28 days. Animals were sacrificed on the 29th day and colon tissues were collected for further examinations.

Results

Diosmetin treatment decreased colonic ulceration dramatically and decreased the percentage of inflammation in the colonic mucosa. Depletion of the TNBS assisted of superoxide dismutase and catalase was substantially restricted, while lipid peroxidation was recorded in the colonic tissue as malondialdehyde content was also decreased. After treatment with diosmetin, the occurrence of TNF-α, IL-6and NF-κB was considerably lowered and the number of apoptotic cells observed was significantly reduced.

Conclusion

Taken together, these observations demonstrated the potential of diosmetin against ulcer formation and development.

Diosmetin inhibits apoptosis and activates AMPK-induced autophagy in myocardial damage under hypoxia environment

Inhibition of hypoxia-induced cardiomyocyte apoptosis is considered as an important treatment method for ischemic heart diseases, but related drugs are still insufficient. The present study aims to explore the protective function and mechanism of the key Chinese medicine monomer diosmetin (DIOS) on the injury of cardiomyocytes induced by hypoxia. Here, AC16 and HCM-a cells were treated with 40 μM of DIOS under hypoxic environment and a hypoxic rat model was built to study the role of DIOS. The viability and autophagy of cardiomyocytes were increased, but the apoptosis of cells was suppressed by 40 μM DIOS, under hypoxic environment. Intriguingly, 10 mM 3-methyladenine, an inhibitor of autophagy, reversed the effect of DIOS on autophagy and apoptosis of the cardiomyocytes under hypoxia. Furthermore, DIOS induced AMP-activated protein kinase (AMPK) activation and Compound C (5 μM), an AMPK inhibitor, attenuated the inhibition of DIOS on the apoptosis of cardiomyocytes under hypoxia environment. In isoprenaline-induced hypoxic rats, it was verified that DIOS inhibited apoptosis, accelerated autophagy, and activated AMPKα pathway in vivo. Our findings indicated that DIOS alleviated hypoxia-induced myocardial apoptosis via inducing the activation of AMPK-induced autophagy. In summary, the study suggested that DIOS inhibited the apoptosis and induced the autophagy of hypoxia-induced cardiomyocytes through AMPK activation.

Diosmetin Induces Modulation of Igf-1 and Il-6 Levels to Alter Rictor-Akt-PKCα Cascade in Inhibition of Prostate Cancer

Growth signals, which typically originate from the surrounding microenvironment, are important for cells. However, when stimulation by growth factors becomes excessive and exceeds their threshold limit, deleterious effects may ensue. In patients with cancer, maintenance of tumors depends, at least in part, on growth factor stimulation, which can also facilitate cancer progression into advanced stages. This is particularly important when the tumor grows beyond its tissue boundaries or when it invades and colonizes other tissues. These aforementioned malignant events are known to be partly supported by elevated cytokine levels. Among the currently known growth signals, insulin-like growth factor (IGF)-1 and IL-6 have been previously studied for their roles in prostate cancer. Both IGF-1 and IL-6 have been reported to activate the RAPTOR independent companion of MTOR complex 2 (Rictor)/AKT/protein kinase C α (PKCα) signaling pathway as one of their downstream mechanisms. At present, research efforts are mainly focused on the exploration of agents that alter growth factor (such as IGF-1) and cytokine (such as IL-6) signaling for their potential application as therapeutic agents, as both of these have been reported to modulate disease outcome. In the present study, IGF-1 and IL-6 served distinct roles in the androgen responsive LNCaP cell line and in the androgen refractory PC-3 cell line in a dose- and time-dependent manner. Increased phosphorylation of Rictor at the Thr-1135 residue, AKT at the Ser-473 residue and PKCα at the Ser-657 residue were observed after treatment with IGF-1 and IL-6. Subsequently, it was found that diosmetin, a natural plant aglycone, had the potential to modulate the downstream signaling cascade of Rictor/AKT/PKCα to inhibit the progression of prostate cancer. Treatment of LNCaP and PC-3 cells with diosmetin inhibited the phosphorylation of Rictor (Thr-1135), AKT (Ser-473) and PKCα (Ser-657) in a dose-dependent manner. Furthermore, the Bax/Bcl-2 expression ratio was increased in response to diosmetin treatment, which would result in increased apoptosis. Based on these observations, diosmetin may represent a novel therapeutic target for prostate cancer.

Crucial Roles of microRNA-Mediated Autophagy in Urologic Malignancies

Urologic oncologies are major public health problems worldwide. Both microRNA and autophagy, separately or concurrently, are involved in a variety of the cellular and molecular processes of multiple cancers, including urologic malignancies. In this review, we have summarized the related studies and found that microRNA-mediated autophagy acted as carcinogenic factors or suppressors in prostate cancer, kidney cancer, and bladder cancer. MiRNAs, targeted genes, and the different signaling pathways constitute a complex network that orchestrates autophagy regulation, militating the oncogenic and tumor-suppressive effects in urologic malignancies. Aberrant expression of miRNAs may induce the dysregulation of the autophagy process, resulting in tumorigenesis, progression, and resistance to anticancer therapies. Targeting specific miRNAs for autophagy modulation may present as reliable diagnostic and prognostic biomarkers or promising therapeutic strategies for urologic oncologies.

Antioxidant Effects of Turmeric Leaf Extract against Hydrogen Peroxide-Induced Oxidative Stress In Vitro in Vero Cells and In Vivo in Zebrafish

Oxidative stress, caused by the excessive production of reactive oxygen species (ROS), results in cellular damage. Therefore, functional materials with antioxidant properties are necessary to maintain redox balance. Turmeric leaves (Curcuma longa L. leaves; TL) are known to have antioxidant properties, including 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2′-Azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), and Hydrogen peroxide (H₂O₂) radical scavenging activity in several studies. The antioxidant effects of TL come from distinct bioactive compounds, such as curcumin, total phenolic compounds, and flavonoids. Therefore, in this study, the antioxidant effects of a water extract of TL (TLE) against H₂O₂ treatment were assessed in vitro Vero cells and in vivo zebrafish models. The intracellular ROS generation and the proportion of sub-G1 phase cells were evaluated in H₂O₂- or/and TLE-treated Vero cells to measure the antioxidant activity of TLE. TLE showed outstanding intracellular ROS scavenging activity and significantly decreased the proportion of cells in the sub-G1 phase in a dose-dependent manner. Furthermore, cell death, ROS generation, and lipid peroxidation in the H₂O₂-treated zebrafish model were attenuated as a consequence of TLE treatment. Collectively, the results from this study suggested that TLE may be an alternative material to relieve ROS generation through its antioxidant properties or a suitable material for the application in a functional food industry.

Diosmetin enhances the sensitivity of radiotherapy by suppressing homologous recombination in endometrial cancer

Radiotherapy is an essential treatment for endometrial cancer (EC), especially in advanced, metastatic, and recurrent cases. Combining radiotherapy, which mainly causes DNA double-strand breaks (DSBs), with small molecules targeting aberrantly activated homologous recombination (HR) repair pathways holds great potential for treating ECs in advanced stages. Here, we demonstrate that diosmetin (DIO), a natural flavonoid, suppresses HR, therefore inhibiting cell proliferation and enhancing the sensitivity of EC to radiotherapy. Clonogenic experiments revealed that combining DIO and X-ray significantly inhibited the viability of EC cells compared to cells treated with diosmetin or X-ray alone. The survival fraction of EC cells decreased to 40% when combining 0.4 Gy X-ray and 4 μM DIO; however, each treatment alone only caused death in approximately 15% and 22% of cancer cells, respectively. Further mechanistic studies showed that diosmetin inhibited the recruitment of RPA2 and RAD51, two critical factors involved in the HR repair pathway, upon the occurrence of DSBs. Thus, we propose that a combination of diosmetin and irradiation is a promising therapeutic strategy for treating endometrial cancer.

Citrus Flavones: An Update on Sources, Biological Functions, and Health Promoting Properties

Citrus spp. are among the most widespread plants cultivated worldwide and every year millions of tons of fruit, juices, or processed compounds are produced and consumed, representing one of the main sources of nutrients in human diet. Among these, the flavonoids play a key role in providing a wide range of health beneficial effects. Apigenin, diosmetin, luteolin, acacetin, chrysoeriol, and their respective glycosides, that occur in concentrations up to 60 mg/L, are the most common flavones found in Citrus fruits and juices. The unique characteristics of their basic skeleton and the nature and position of the substituents have attracted and stimulated vigorous investigations as a consequence of an enormous biological potential, that manifests itself as (among other properties) antioxidant, anti-inflammatory, antiviral, antimicrobial, and anticancer activities. This review analyzes the biochemical, pharmacological, and biological properties of Citrus flavones, emphasizing their occurrence in Citrus spp. fruits and juices, on their bioavailability, and their ability to modulate signal cascades and key metabolic enzymes both in vitro and in vivo. Electronic databases including PubMed, Scopus, Web of Science, and SciFinder were used to investigate recent published articles on Citrus spp. in terms of components and bioactivity potentials.

Inhibition of TGF-β Signaling in Gliomas by the Flavonoid Diosmetin Isolated from Dracocephalum peregrinum L

Background: Dracocephalum peregrinum L., a traditional Kazakh medicine, has good expectorant, anti-cough, and to some degree, anti-asthmatic effects. Diosmetin (3',5,7-trihydroxy-4'-methoxyflavone), a natural flavonoid found in traditional Chinese herbs, is the main flavonoid in D. peregrinum L. and has been used in various medicinal products because of its anticancer, antimicrobial, antioxidant, estrogenic, and anti-inflammatory effects. The present study aimed to investigate the effects of diosmetin on the proliferation, invasion, and migration of glioma cells, as well as the possible underlying mechanisms. Methods: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), scratch wound, and Transwell assays were used to demonstrate the effects of diosmetin in glioma. Protein levels of Bcl-2, Bax, cleaved caspase-3, transforming growth factor-β (TGF-β), E-cadherin, and phosphorylated and unphosphorylated smad2 and smad3 were determined by Western blots. U251 glioma cell development and progression were measured in vivo in a mouse model. Results: Diosmetin inhibited U251 cell proliferation, migration, and invasion in vitro, the TGF-β signaling pathway, and Bcl-2 expression. In contrast, there was a significant increase in E-cadherin, Bax, and cleaved caspase-3 expression. Furthermore, it effectively reduced the tumorigenicity of glioma cells and promoted apoptosis in vivo. Conclusion: The results of this study suggest that diosmetin suppresses the growth of glioma cells in vitro and in vivo, possibly by activating E-cadherin expression and inhibiting the TGF-β signaling pathway.

Investigations on the structural, vibrational, computational, and molecular docking studies on potential antidiabetic chemical agent Diosmetin

In the present study, the harmonic vibrational frequencies of Diosmetin(5, 7 dihydroxy-2(3-hydroxy-4 methoxyphenyl) chromen-4-one) have been investigated by both experimental (FTIR and FT-Raman) and theoretical (HF and DFT/B3LYP) method. The calculated harmonic vibrational frequencies were compared with experimental data. A detailed interpretation of the vibrational spectra of the compound has been made on the basis of the calculated potential energy distribution (PED). The ¹ H, ¹³ C NMR chemical shifts and TD-DFT calculations of the molecule were calculated and compared with the available experimental observations. A study on the molecular electrostatic potential surface (MEP) of the compound was performed, and the electrophilic and nucleophilic reactive sites were identified. Furthermore, the inhibition effect of compound against aldose reductase enzyme has been analyzed by molecular docking method, and the results were compared with the standard drug. The docking study indicates that the investigated compound shows better inhibitory activity toward aldose reductase enzyme than the standard drug, and hence this study may be supportive in the field of drug discovery to design more potential antidiabetic agents.

Cytotoxic effect of aqueous ethanolic extract of Luffa cylindrica leaves on cancer stem cells CD44+/24- in breast cancer patients with various molecular sub-types using tissue samples in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Luffa cylindrica (L.) M.Roem is a climbing plant its parts have been used as traditional medicine for the treatment of different types of diseases including diarrhea, inflammation, cancer and viral infections. The parts used include fruit, seeds and leaves.

AIM OF THE STUDY

Our study aims to investigate the effect of the aqueous-ethanol extract of Luffa cylindrica leaves on breast cancer stem cells CD44⁺/24^- and other cell sub-populations using clinical samples with different molecular sub-types of breast cancer in vitro.

MATERIALS AND METHODS

Breast tissues were obtained from patients undergoing surgery for the removal of breast tumors after complete clinical and pathological investigations. Tissue samples were processed to cell suspensions and treated with the extract in the tissue culture laboratory. Percentages of cell sub-populations within tumors and viability were measured by flowcytometry using clusters of differentiation as cell markers.

RESULTS

Our results revealed that there were decreases in the total cell viability, CD44⁺/24^- and total CD24⁺ cell sub-populations percentages after treatment with the extract, this may be an important indication of using Luffa leaves extract in the treatment of breast cancer or in combination with the traditional treatments.

CONCLUSION

Luffa cylindrica has proven to have anticancer activity on three different subtypes of breast cancer including luminal A, luminal B and Her2/neu enriched more over it has cytotoxic effect on both bulk tumor cells as well as cancer stem cells sub population CD44⁺/24^- which possess high tumorigenic potency, these results were confirmed by measuring their viable number after treatment and sphere formation assay results.

UHPLC-ESI-ORBITRAP-MS analysis of the native Mapuche medicinal plant palo negro (Leptocarpha rivularis DC. - Asteraceae) and evaluation of its antioxidant and cholinesterase inhibitory properties

UHPLC/ESI/MS identification of organic compounds is the first step in the majority of screening techniques for the characterization of biologically active metabolites in natural sources. This paper describes a method for the fast identification and characterisation of secondary metabolites in Leptocarpha rivularis DC. (Palo negro) extracts by HPLC/UV (DAD)–Mass Spectrometry (HPLC/MS). The plant is used for the treatment of several diseases since pre-hispanic Mapuche times. Thirty-seven compounds were detected in the aqueous edible extract for the first time including 4 sesquiterpenes, 10 flavonoids, 9 oxylipins, 2 organic acids, and 11 phenolic acids. In addition, phenolic content antioxidant and cholinesterase inhibitory activities were measured for the first time using the edible infusion. The total polyphenol content of the infusion was 230.76 ± 2.5 mmol GAE/kg dry weight, while the antioxidant activity was 176.51 ± 28.84; 195.28 ± 4.83; and 223.92 ± 2.95 mmol TE/kg dry weight, for the DPPH, ABTS, and FRAP assays, respectively. The cholinesterase inhibitory activity was 7.38 ± 0.03 and 5.74 ± 0.06 mmol GALAE/kg, for the inhibition of acetylcholinesterase AChE and BChE, respectively, showing that this plant is a candidate for the isolation of compounds that can be useful for the treatment of neurodegenerative diseases. Furthermore, this plant could serve also as a raw material for the production of dietary supplements, due to its content of polyphenolic compounds.

Diosmetin suppresses human prostate cancer cell proliferation through the induction of apoptosis and cell cycle arrest

Diosmetin, a plant flavonoid, has been shown to exert promising effects on prostate cancer cells as an anti‑proliferative and anticancer agent. In this study, using western blot analysis for protein expression and flow cytometry for cell cycle analysis, we determined that the treatment of the LNCaP and PC‑3 prostate cancer cells with diosmetin resulted in a marked decrease in cyclin D1, Cdk2 and Cdk4 expression levels (these proteins remain active in the G0‑G1 phases of the cell cycle). These changes were accompanied by a decrease in c-Myc and Bcl-2 expression, and by an increase in Bax, p27Kip1 and FOXO3a protein expression, which suggests the potential modulatory effects of diosmetin on protein transcription. The treatment of prostate cancer cells with diosmetin set in motion an apoptotic machinery by inhibiting X-linked inhibitor of apoptosis (XIAP) and increasing cleaved PARP and cleaved caspase-3 expression levels. On the whole, the findings of this study provide an in-depth analysis of the molecular mechanisms responsible for the regulatory effects of diosmetin on key molecules that perturb the cell cycle to inhibit cell growth, and suggest that diosmetin may prove to be an effective anticancer agent for use in the treatment of prostate cancer in the future.

The Sineoculis Homeobox Homolog 1 (SIX1) Gene Regulates Paclitaxel Resistance by Affecting Reactive Oxygen Species and Autophagy in Human Hepatocellular Carcinoma Cell Line HepG2

Background

The objective of this study was to explore the role of SIX1 in paclitaxel (TAX) resistance of HepG2 cells via reactive oxygen species (ROS) and autophagy pathway.

Material/Methods

Hepatoma cell line HepG2 was treated with SIX1 knockdown or/and TAX. Cell growth was detected by MTT assay and colony formation assay. Cell apoptosis was evaluated with flow cytometry. ROS levels were detected using flow cytometry (stained with DCFH2-DA). Western blot was conducted to detect the expression of SIX1 and autophagy-related proteins.

Results

TAX suppressed the proliferation of HepG2 cells in a time/dose-dependent manner, and upregulated the expression of SIX1. SIX1 siRNA increased TAX sensitivity of HepG2 cells and upregulated cell ROS levels. SIX1 siRNA combined with TAX treatment activated autophagy of HepG2 cells. N-acetyl-L-cysteine (NAC) partially attenuated SIX1 siRNA-induced ROS level increases, and autophagy inhibitor 3-MA notably enhanced SIX1 siRNA-induced cell apoptosis.

Conclusions

Knockdown of SIX1 increased cell ROS levels and autophagy, promoted cell apoptosis, and enhanced TAX sensitivity of HepG2 cells.

Autophagy suppresses proliferation of HepG2 cells via inhibiting glypican-3/wnt/β-catenin signaling

Introduction

Autophagy plays an important role in the growth and survival of hepatocellular carcinoma (HCC) cells through several target proteins or signaling pathways. Glypican-3 (GPC3) is a new reliable HCC marker, which is involved in tumor growth in HCC, primarily mediated by wnt/β-catenin signaling.

Objective

The present study aimed to identify the role of autophagy in the proliferation of HepG2 cells through GPC3/wnt/β-catenin signaling.

Results and discussion

Results demonstrated that induction of autophagy by nutrition starvation and rapamycin treatment led to the downregulation of GPC3 expression in HepG2 cells, accompanied by the decreased expression of wnt downstream target genes (β-catenin, c-myc and cyclin D1). On the other hand, inhibition of autophagy by 3-methyl adenine (3-MA) could rescue rapamycin-directed downregulation of GPC3 and wnt/β-catenin target genes and augment the proliferation of HepG2 cells. Furthermore, interference of GPC3 by siRNA suppressed wnt/β-catenin signaling and attenuated 3-MA stimulation of HepG2 cell proliferation. More interestingly, the mRNA of GPC3 remained unchanged when the protein levels of GPC3 were decreased by autophagy activation, suggesting that induction of autophagy may accelerate the degradation of GPC3.

Conclusion

These results suggest that autophagy suppresses proliferation of HepG2 cells partially by inhibition of GPC3/wnt/β-catenin signaling.

Preoperative application of combination of portal venous injection of donor spleen cells and intraperitoneal injection of rapamycin prolongs the survival of cardiac allografts in mice

OBJECTIVE

To investigate the effects of preoperative portal venous injection of donor spleen cells (PVIDSC) and intraperitoneal injection of rapamycin in the acute rejection of cardiac allograft in mice and the underlying mechanisms.

METHODS

Homogenous female B6 mice and BALB/c mice were used as recipients and donors of heart transplantation. These mice were randomly divided into different groups and received PVIDSC alone, rapamycin alone, or PVIDSC and rapamycin combined therapy. In addition, the underlying mechanism was studied by measuring a number of cytokines.

RESULTS

Preoperative combination of PVIDSC and intraperitoneal injection of rapamycin significantly prolonged the survival of heterotopic cardiac allograft in mice, but had no effects on the survival time of cardiac allografts in mice pre-sensitized by skin grafting. Preoperative combination of PVIDSC and intraperitoneal injection of rapamycin increased the expression of IL-10 and Foxp3 and reduced the expression of INF-. Short-term preoperative administration of rapamycin promotes the expression of CD4⁺CD25⁺Foxp3⁺ regulator T cells. However, preoperative using alone of rapamycin, or combination of PVIDSC and rapamycin had no effects on the inhibition of proliferation of memory T cells.

CONCLUSIONS

Preoperative application of combination of PVIDSC and rapamycin significantly prolonged the survival time of cardiac allografts in mice but not in mice pre-sensitized by skin grafting. This may be explained by the fact that combination of PVIDSC and rapamycin inhibited the cellular immune response and induced the expression of IL-10 from Tr1 cells and CD4⁺CD25⁺FoxP3⁺ regulatory T cells.