Acriflavine Research Articles

3D-printed implants loaded with acriflavine for glioblastoma treatment

Drug delivery routes play an essential role in determining the efficacy and safety of medications. This study focused on the development and optimization of 3D-printed reservoir type implants as a combinational therapy drug delivery system for Glioblastoma Multiforme (GBM) post-surgery, possessing also antibacterial properties. In this study, we used a multimodal agent, Acriflavine (ACF) as an alternative drug to treat GBM. To date, ACF is used only as an antiseptic agent, although it has been shown to possess strong anticancer activities. ACF and a low molecular weight PCL were loaded into 3D-printed reservoir-type implants for sustained drug delivery. The study demonstrated that ACF implants exhibited sustained drug release kinetics, with faster release during the initial 30 days, followed by a gradual decrease over 90 days. This controlled release profile enhances the effectiveness of ACF delivery to tumour targets while minimizing side effects associated with systemic administration. In vitro experiments confirmed the inhibitory activity of ACF against GBM cells compared to non-tumour cells. The study also highlighted the bacteriostatic effects of ACF, making the implants potentially useful for post-surgery infection management, particularly against S. aureus, a common bacterial infection associated with brain surgery. The long-term drug-release capabilities of the implants make them attractive candidates for both tumour inhibition and antibacterial treatment. The study suggests that the developed ACF delivery systems have the potential for future clinical studies. Their ability to provide increased drug efficacy without systemic toxicity makes them promising candidates for cancer therapy and post-surgery infection management.

Effect of Partial Elimination of Mitochondrial DNA on Genome-Wide Identified AOX Gene Family in Chlamydomonas reinhardtii

Using Chlamydomonas as a model organism, we attempted to eliminate mitochondrial DNA (mtDNA) similar to rho0 or rho− cells (completely or partially mtDNA-eliminated cells) in yeast. We successfully generated partially mtDNA-eliminated cells named as crm- cells, causing the inactivation of mitochondrial activity. We used three different chemicals to eliminate mtDNA including acriflavine (AF), ethidium bromide (EB) and dideoxycytidine (ddC) which prevents replication, inhibits POLG (DNA polymerase gamma) and terminates the mtDNA chain, respectively. The qPCR method was used to detect the mtDNA copy number and the selected rrnL6 gene for the detection of mitochondria, as well as the selected Chlamydomonas CC-124 strain. A reduction in the mitochondrial copy number led to a higher expression of AOX1, UCP1, PGRL1 and ICL1, which indicates the disturbance of the mitochondria–chloroplast ATP and NADPH balance. We selected AOX genes to further study this family and carried out a genome-wide search to identify AOX genes in green algae (C. reinhardtii). Our results revealed that C. reinhardtii contains four AOX genes, i.e., CrAOX1, CrAOX2, CrAOX3 and CrAOX4, which are distributed on Chr 3, Chr7 and Chr9. All CrAOX genes were predicted to localize in mitochondria using bioinformatics tools. Phylogenetic analysis suggests that these CrAOXs are subdivided into four groups and genes existing in the same group could perform identical functions. Collinearity analysis describes the strong evolutionary relationships of AOXs between the unicellular green algae Chlamydomonas reinhardtii and the multicellular green algae Volvox carteri. GO (gene ontology) annotation analysis predicted that CrAOXs played an integral part in carrying out alternate oxidative and respirative activities. Three putative miRNAs, cre-miR1162-3p, cre-miR1171 and cre-miR914, targeting the CrAOX2 gene were identified. Our studies have laid a foundation for the further use of partially mtDNA-eliminated cells and elucidating the functional characteristics of the AOX gene family.

Cell-Membrane-Coated Metal-Organic Framework Nanocarrier Combining Chemodynamic Therapy for the Inhibition of Hepatocellular Carcinoma Proliferation.

Chemodynamic therapy (CDT) employs hydrogen peroxide (H2O2) within the tumor microenvironment (TME) to initiate the Fenton reaction and catalyze the generation of hydroxyl radicals (·OH) for targeted therapy. Metal ion-based nanomaterials have garnered significant attention as catalysts due to their potent anti-tumor effects. Hypoxia in the TME is often associated with cancer cell development and metastasis, with HIF-1α being a pivotal factor in hypoxia adaptation. In this study, an organic framework called MIL-101 (Fe) was designed and synthesized to facilitate H2O2-induced ·OH production while also serving as a carrier for the HIF-1α inhibitor Acriflavine (ACF). A biomimetic nanomedical drug delivery system named MIL-101/ACF@CCM was constructed by encapsulating liver cancer cell membranes onto the framework. This delivery system utilized the homologous targeting of tumor cell membranes to transport ACF, inhibiting HIF-1α expression, alleviating tumor hypoxia, and catalyzing ·OH production for effective tumor eradication. Both in vivo and in vitro experiments confirmed that combining ACF with chemotherapy achieved remarkable tumor inhibition by enhancing ROS production and suppressing HIF-1α expression.

HIF‐1α‐inhibited Nanophotosensitizers for Near‐infrared Fluorescence Imaging‐guided Enhanced Photodynamic Therapy

AbstractPhotodynamic therapy (PDT) holds great potential in cancer therapy by virtue of its high precision, non‐invasiveness and low side effect. However, the hypoxic environment of solid tumor significantly restricts the efficacy of PDT. To improve the hypoxic microenvironment, inhibiting the hypoxia‐inducible factor 1α (HIF‐1α) is a rational approach. However, the related small molecule inhibitors suffer from the issue of poor tumor targeting. Herein, we design a nanophotosensitizer AmPPa NP which can inhibit HIF‐1α and conduct PDT with improved efficacy. AmPPa NP is prepared by first encapsulating a hydrophobic NIR photosensitizer mPPa into a carboxyl‐rich amphiphilic copolymer PSMA‐PEG, and then loading a positively charged HIF‐1α inhibitor acriflavine (ACF) on the surface of nanoparticle via electrostatic interaction. Under 635 nm laser irradiation, mPPa within nanoparticles can not only generate 1O2 for PDT but also emit NIR fluorescence signal for tumor imaging. In addition, such design makes ACF can be selectively released under acidic tumor microenvironment. Compared with mPPa NP without ACF loading, AmPPa NP can effectively inhibit HIF‐1α and shows improved PDT efficacy both in vitro and in vivo. This study thus provides a nanotheranostic platform for NIR fluorescence imaging‐guided enhanced PDT.

Intermittent Hypoxia Mediates Cancer Development and Progression Through HIF-1 and miRNA Regulation

IntroductionThere is still a debate for the link between obstructive sleep apnoea (OSA) and cancer. The mechanisms underlying this causality are poorly understood. Several miRNAs are involved in cancer development and progression with expression being influenced by hypoxia.The aims of this work were (i) to compare miRNAs expression in controls versus patients affected by OSA without or with cancer (ONCO-OSA) and (ii) in colorectal cancer cells exposed to intermittent hypoxia (IH), to evaluate miRNAs impact on tumor progression in vitro. MethodsWe detected miRNAs by qRT-PCR in patients’ sera and in CaCo2 cells exposed to 2–32h of IH with or without acriflavine (ACF), a HIF-1 inhibitor. Viability and transwell invasion test were applied to investigate the proliferation and migration of CaCo2 exposed to IH and treated with miRNA inhibitors or acriflavine. HIF-1α activity was evaluated in CaCo2 cells after IH. ResultsThe levels of miR-21, miR-26a and miR-210 increased in OSA and ONCO-OSA patients compared to controls. MiR-23b increased in ONCO-OSA patients, and miR-27b and miR-145 increased in OSA but not ONCO-OSA patients. MiR-21, miR-26a, miR-23b and miR-210 increased in cells after IH. IH stimulated cell proliferation and migration. This effect was reduced after either miRNA inhibition or acriflavine treatment. MiRNA inhibition reduces HIF-1α gene expression. Conversely, acriflavine reduced the expression of these miRNAs. ConclusionsWe identified a signature of miRNAs, induced by the IH environment. They could be implicated in cancer development and progression through a regulatory loop involving HIF-1.

Tunable White Light Emission of a Metal-Organic Framework Based on a Bisquinoxaline Derivative by Introducing Red-Green Cationic Dyes.

The unique structural advantages give metal-organic frameworks (MOFs) a special use as host substrates to encapsulate organic dyes, which would result in specific host-guest composites for white-light phosphors. In this work, an anionic MOF exhibiting blue emission was constructed using bisquinoxaline derivatives as photoactive centers, which could effectively encapsulate rhodamine B (Rh B) and acriflavine (AF) to form an In-MOF ⊃ Rh B/AF composite. By simply adjusting the amount of Rh B and AF, the emitting color of the resulting composite could be easily adjusted. The formed In-MOF ⊃ Rh B/AF composite exhibits broadband white light emission with ideal Commission International ed'Eclairage (CIE) coordinates of (0.34, 0.35), a color rendering index of 80.8, and a moderately correlated color temperature value of 5193.96 K. This strategy can be easily extended to other blue-emitting MOFs and dyes, thus opening up new prospects for the development of white-light-emitting materials.

A comprehensive study on the adsorption, corrosion inhibition efficiency and stability of acriflavine on mild steel in 1 M HCl solution

A comprehensive study was conducted on the adsorption, corrosion inhibition efficiency and stability of acriflavine (ACF) on mild steel (MS) in 1 M HCl solution. Electrochemical studies were conducted to determine the corrosion protection ability of the inhibitor after short and long immersion times. The MS surface after exposing to the uninhibited and inhibited solutions were characterized by SEM, EDX, AFM and contact angle measurements. The excess surface charge of the metal and some thermodynamic parameters were derived after 1 h and 6 h exposure times and a possible adsorption and inhibition mechanism was discussed. The electrochemical stability of the inhibitor film formed on the metal surface was studied using potentiodynamic and potentiostatic techniques. It was found that ACF adsorbs on the MS surface via dominantly chemical and weakly physical interactions and forms a protective surface film. The film was adherent, uniform, protective and electrochemically stable. The inhibitor film provides maximum inhibition efficiencies of 92.8% and 97.1% at 1 mM after 1 h and 6 h immersion times. ACF mitigates the rates of both anodic metal dissolution and cathodic hydrogen evolution reactions. The excess surface charge of the steel in the inhibited solution was negative, which becomes more evident after longer exposure time.

Fe3O4@CMC-Cu magnetic nanocomposite as an efficient catalyst for reduction of toxic pollutants in water

Metallic nanoparticles embedded in the polymer matrix are considered a significant category of heterogeneous catalysts with strong catalytic performance. Functionalized polymers are inexpensive building blocks that make good catalytic platforms for stabilizing metallic nanoparticles. In this study, Fe3O4@CMC-Cu magnetic nanocomposites were successfully synthesized and characterized by XRD, FTIR, BET, XPS, VSM, HR-TEM, and EDX mapping. Morphology observation shows that spherical Fe3O4 magnetic nanoparticles and Cu NPs are distributed uniformly and encapsulated inside the polymer structure with an average diameter of ∼ 11 nm without substantial agglomeration. Additionally, the inclusion of CMC polymer and Cu NPs gradually reduces the magnetic saturation of Fe3O4. The reduction of 4-nitrophenol (4-NP) and the organic dyes Congo red (CR) and acriflavine (ACF) in aqueous medium at room temperature was used to test the nanocomposites' catalytic activity. The effects of reaction parameters, catalyst amount and Cu NPs percentages on the catalytic effectiveness were determined. The induction time of the reaction decreases with increasing the nanocomposite amount and the Cu NPs loading percentages. Excellent catalytic activity was demonstrated by the Fe3O4@CMC-Cu (10 %) nanocomposite for the elimination of all three intended organic contaminants (4-NP, CR and ACF). For the reduction of 4-NP, CR, and ACF, the calculated Kapp values were 1.55 min−1, 0.3 min−1, and 2.3 min−1, respectively. The magnetic nanocomposite was easily separated from the reaction solution and recycled for up to five successive cycles without suffering a substantial decrease in the catalytic activity. Such magnetic nanocomposites provide light on highly effective catalysts for applications in environmental protection.

HIF-1 inhibitor-based one-stone-two-birds strategy for enhanced cancer chemodynamic-immunotherapy.

Based on its ability to induce strong immunogenic cell death (ICD), chemodynamic therapy (CDT) was elaborately designed to combine with immunotherapy for a synergistic anticancer effect. However, hypoxic cancer cells can adaptively regulate hypoxia-inducible factor-1 (HIF-1) pathways, leading to a reactive oxygen species (ROS)-homeostatic and immunosuppressive tumor microenvironment. Consequently, both ROS-dependent CDT efficacy and immunotherapy are largely diminished, further lowering their synergy. Here, a liposomal nanoformulation co-delivering a Fenton catalyst copper oleate and a HIF-1 inhibitor acriflavine (ACF) was reported for breast cancer treatment. Through in vitro and in vivo experiments, copper oleate-initiated CDT was proven to be reinforced by ACF through HIF-1-glutathione pathway inhibition, thus amplifying ICD for better immunotherapeutic outcomes. Meanwhile, ACF as an immunoadjuvant significantly reduced the levels of lactate and adenosine, and downregulated the expression of programmed death ligand-1 (PD-L1), thereby promoting the antitumor immune response in a CDT-independent manner. Hence, the "one stone" ACF was fully taken advantage of to enhance CDT and immunotherapy (two birds), both of which contributed to a better therapeutic outcome.

Multifunctional semiconducting carbon nitrides enabling sequential fluorescent sensing of telomerase activity and internal self-checking

Improving the detection reliability of biosensors is essential but challenging. The dual-signal self-checking function is useful for the development of reliable biosensors; however, it inevitably increases the complexity of the sensing system. Thus, biosensors with intrinsic self-checking functions that do not require additional chemicals, specific sensor assemblies, and/or instruments are highly desirable. Herein, integrating the ability of fluorescence detection and photodegradation by carbon nitride nanosheets (CNNS), a biosensor with a self-checking function for sensitive telomerase activity detection was constructed. Acriflavine (AF) was screened from various dyes to form the most effective CNNS-AF donor-acceptor (D-A) interfaces by experiments and density functional theory (DFT) calculations, considering spectral match, electrostatic interaction, and non-covalent stacking. As a result, the proposed fluorescence biosensor not only showed highly sensitive detection of telomerase activity but also had an internal self-checking function by photodegradation of AF via continuous excitation and measurement of recovered fluorescence. This study sheds light on CNNS-based D-A interfaces with synergistic fluorescence detection and photocatalysis-induced self-checking properties for future clinical diagnosis with high sensitivity and reliability.

Therapeutic potential of topical administration of acriflavine against hypoxia-inducible factors for corneal fibrosis.

Transdifferentiation of keratocytes into fibroblasts or further into myofibroblasts, which produced denser and more disorganized extracellular matrix, is the major cause of corneal fibrosis and scarring, leading to corneal blindness. TGF-β1 is the critical cytokine for the myofibroblast's transdifferentiation and survival. Hypoxia Inducible Factor (HIF) was found to play an important role in promoting fibrosis in lung, kidney, and dermal tissues recently. Our preliminary study demonstrated that topical administration of the acriflavine (ACF), a drug inhibiting HIF dimerization, delayed corneal opacity and neovascularization after the alkali burn. To know whether ACF could prevent corneal fibrosis and improve corneal transparency, we created a mouse mechanical corneal injury model and found that topical administration of ACF significantly inhibited corneal fibrosis at day 14 post-injury. The reduction of myofibroblast marker α-SMA, and fibronectin, one of the disorganized extracellular matrix molecules, in the corneal stroma were confirmed by the examination of immunohistochemistry and real-time PCR. Furthermore, the ACF inhibited the expression of α-SMA and fibronectin in both TGF-β1 stimulated or unstimulated fibroblasts in vitro. This effect was based on the inhibition of HIF signal pathways since the levels of the HIF-1α downstream genes including Slc2a1, Bnip3 and VEGFA were downregulated. To our knowledge, this is the first time to implicate that HIFs might be a new treatment target for controlling corneal fibrosis in mechanical corneal injuries.

Acriflavine and proflavine hemisulfate as potential antivirals by targeting Mpro

The evolving SARS-CoV-2 epidemic buffets the world, and the concerted efforts are needed to explore effective drugs. Mpro is an intriguing antiviral target for interfering with viral RNA replication and transcription. In order to get potential anti-SARS-CoV-2 agents, we established an enzymatic assay using a fluorogenic substrate to screen the inhibitors of Mpro. Fortunately, Acriflavine (ACF) and Proflavine Hemisulfate (PRF) with the same acridine scaffold were picked out for their good inhibitory activity against Mpro with IC50 of 5.60 ± 0.29 μM and 2.07 ± 0.01 μM, respectively. Further evaluation of MST assay and enzymatic kinetics experiment in vitro showed that they had a certain affinity to SARS-CoV-2 Mpro and were both non-competitive inhibitors. In addition, they inhibited about 90 % HCoV-OC43 replication in BHK-21 cells at 1 μM. Both compounds showed nano-molar activities against SARS-CoV-2 virus, which were superior to GC376 for anti-HCoV-43, and equivalent to the standard molecule remdesivir. Our study demonstrated that ACF and PRF were inhibitors of Mpro, and ACF has been previously reported as a PLpro inhibitor. Taken together, ACF and PRF might be dual-targeted inhibitors to provide protection against infections of coronaviruses.

Targeting Tumor Hypoxia Inhibits Aggressive Phenotype of Dedifferentiated Thyroid Cancer.

Hypoxia is commonly observed in multiple aggressive cancers. Its role remains unclear in the biology and therapy of dedifferentiated thyroid cancer (DDTC). We aimed to elucidate hypoxia's roles in DDTC tumor biology. We discovered and confirmed hypoxia's correlation with dedifferentiation status, poor prognoses, and immune checkpoints in thyroid cancer using transcriptome data from our center and Gene Expression Omnibus (GEO) database. Then, the effect of targeting hypoxia was investigated via treating anaplastic thyroid cancer (ATC) cells with acriflavine (ACF) in vitro and in vivo, and hypoxia was analyzed for its association with response to immunotherapy in patients. Hypoxia score was positively associated with dedifferentiation status, and high hypoxia score significantly correlated with reduced overall survival, TP53 mutation, and elevated expression of immunosuppression-related markers in DDTC. ACF and siRNA targeting HIF-1α significantly suppressed growth and proliferation of thyroid cancer cells in vitro and in vivo, and reduced c-MYC and PDL1 expression in ATC. HIF-1α showed a positive correlation with PDL1 expression in DDTC. Integrated analyses of phosphoproteome and RNA sequencing data revealed that ACF's target was connected with differentiation genes and immune checkpoints via tumor-related kinases in ATC. Furthermore, hypoxia score was associated with immunotherapeutic response in some cancer types. Hypoxia score serves as a significant indicator for dedifferentiation status, prognoses, and immunotherapeutic response predicted by Tumor Immune Dysfunction and Exclusion in DDTC patients. Targeting hypoxia by ACF is useful to alleviate aggressive phenotype of ATC in a preclinical model of DDTC.

Acriflavine, an Acridine Derivative for Biomedical Application: Current State of the Art.

Acriflavine (ACF) has been known for years as an antibacterial drug. The identification of key oncogenic mechanisms has brought, in recent years, a significant increase in studies on ACF as a multipurpose drug that would improve the prognosis for cancer patients. ACF interferes with the expression of the hypoxia inducible factor, thus acting on metastatic niches of tumors and significantly enhancing the effects of other anticancer therapies. It has been recognized as the most potent HIF-1 inhibitor out of the 336 drugs approved by the FDA. This work presents up-to-date knowledge about the mechanisms of action of ACF and its related prodrug systems in the context of anticancer and SARS-CoV-2 inhibitory properties. It explains the multitask nature of this drug and suggests mechanisms of ACF’s action on the coronavirus. Other recent reports on ACF-based systems as potential antibacterial and antiviral drugs are also described.

The Activation of the Tumor Suppressor Protein p53 by Acriflavine Leads to Mitochondrial Dysfunction and Improves the Radiosensitivity of Colon Cancer Cells.

Colon cancer ranks third worldwide, and it has a growing incidence with urbanization and industrialization. Drug resistance in colon cancer is gradually affecting the treatment. This study focused on the mechanisms by which acriflavine (ACF) enhances the radiosensitivity of colon cancer cells. First, the expression and activation levels of tumor suppressor protein p53 were shown high in normal cells and tissues in its detection, which suggests that p53 is likely to be a key factor in colon cancer. Then, the expression of p53 ended up increasing in ACF group after SW620 cells were cultured with ACF. In addition, ACF group had some other changes. The expression of mitochondrial related antiapoptotic protein Bcl-2 increased, while the expression of proapoptotic protein Bax, Bad, cytopigment C, and apoptotic inducer AIF decreased. At the same time, the ability of apoptosis was enhanced, and the ability of proliferation and invasion was decreased. This suggests that ACF can promote p53 expression and affect mitochondrial function and the radiosensitivity of SW620. The luciferase reporting experiment showed that there was a binding site between ACF and p53. Besides, when IR treatment was applied to SW620 with high p53 expression, there was an increase in the expression of Bcl-2 in SW620 and decrease in Bax, Bad, and cytopigment C in AIF. Meanwhile, the cell apoptosis became stronger, and the proliferation and invasion became weaker. The experimental results were similar to those of SW620 cells cultured with ACF, suggesting that p53 is an intermediate factor in the regulation of SW620 by ACF. Finally, in this study, cells were cultured with ACF, and p53 was knocked down at the same time. The experimental results showed that after p53 was knocked down. ACF's ability to regulate SW620 is partially removed. This confirms the view that ACF regulates SW620 cells by regulating p53. In summary, this study found the mechanism by which ACF causes mitochondrial dysfunction and improves the radiosensitivity of colon cancer cells by activating the tumor suppressor protein p53, which may contribute to solving the drug resistance in colon cancer.

CYP1A1, VEGFA and Adipokine Responses of Human Adipocytes Co-exposed to PCB126 and Hypoxia.

It is increasingly recognized that hypoxia may develop in adipose tissue as its mass expands. Adipose tissue is also the main reservoir of lipophilic pollutants, including polychlorinated biphenyls (PCBs). Both hypoxia and PCBs have been shown to alter adipose tissue functions. The signaling pathways induced by hypoxia and pollutants may crosstalk, as they share a common transcription factor: aryl hydrocarbon receptor nuclear translocator (ARNT). Whether hypoxia and PCBs crosstalk and affect adipokine secretion in human adipocytes remains to be explored. Using primary human adipocytes acutely co-exposed to different levels of hypoxia (24 h) and PCB126 (48 h), we observed that hypoxia significantly inhibits the PCB126 induction of cytochrome P450 (CYP1A1) transcription in a dose-response manner, and that Acriflavine (ACF)—an HIF1α inhibitor—partially restores the PCB126 induction of CYP1A1 under hypoxia. On the other hand, exposure to PCB126 did not affect the transcription of the vascular endothelial growth factor-A (VEGFA) under hypoxia. Exposure to hypoxia increased leptin and interleukin-6 (IL-6), and decreased adiponectin levels dose-dependently, while PCB126 increased IL-6 and IL-8 secretion in a dose-dependent manner. Co-exposure to PCB126 and hypoxia did not alter the adipokine secretion pattern observed under hypoxia and PCB126 exposure alone. In conclusion, our results indicate that (1) hypoxia inhibits PCB126-induced CYP1A1 expression at least partly through ARNT-dependent means, suggesting that hypoxia could affect PCB metabolism and toxicity in adipose tissue, and (2) hypoxia and PCB126 affect leptin, adiponectin, IL-6 and IL-8 secretion differently, with no apparent crosstalk between the two factors.

Thymoquinone has a synergistic effect with PHD inhibitors to ameliorate ischemic brain damage in mice

BackgroundA blockage in a blood vessel can cause reduced blood flow to the brain, which eventually leads to the death of surrounding tissue. Several studies have attempted to develop an effective intervention to reverse this process and improve the health status of affected individuals. Due to its indirect effect on cellular functions and metabolism, the hypoxia-inducible factor (HIF-1α) protein has been proposed as a promising transcription factor in the treatment of stroke. PurposeThe current study aims to explore the relation between HIF-1 α and thymoquinone (TQ) in the attenuation of ischemic brain damage and the possible mechanism of this relation to reduce cell death. MethodsFor this purpose, dimethyloxallyl glycine (DMOG), 8 mg/kg, Acriflavine (ACF), 1.5 mg/kg, and both combined with TQ (5 mg/kg) were assessed. Male C57 mice were used to establish an ischemic stroke model by using endothelin-1 (ET-1) (400 pmole/μl) intra- cranial injection. The ultrastructure alterations of neuronal soma, axons, and mitochondria after stroke and treatment were well addressed. Besides, the expression levels of VEGF, HIF-1α, Nrf2, and HO-1 were evaluated. Meanwhile, apoptosis and autophagy-related proteins were also investigated. ResultsTreatment of ischemic stroke by TQ can activate the HIF-1α pathway and its downstream genes such as VEGF, TrkB, and PI3K, which in turn enhance angiogenesis and neurogenesis. Our study revealed that TQ has the same effect as DMOG to activate HIF-1 α and can improve motor dysfunction after ischemic stroke. Further, we demonstrated that both TQ and DMOG effectively attenuate the organelle's damage following ischemic stroke, which was confirmed by the cryogenic transmission electron microscope. The synergistic effect of TQ and DMOG may lead to a chemo-modulation action in the autophagy process after stroke onset and this result is validated by the western blot and rt-qPCR techniques. ConclusionOur finding revealed the potential role of TQ as a HIF-1 α activator to reduce cell death, modulate autophagy and decrease the infarct volume after ischemic stroke onset. The neuroprotective effect of TQ is achieved by decreasing the inflammation and increasing angiogenesis as well as neurogenesis via induction of the HIF-1α-VEGF/Nrf2-HO-1-TrkB-PI3K pathway.

Zirconium-Based Metal-Organic Frameworks as Acriflavine Cargos in the Battle against Coronaviruses─A Theoretical and Experimental Approach.

In this study, we present a complementary approach for obtaining an effective drug, based on acriflavine (ACF) and zirconium-based metal–organic frameworks (MOFs), against SARS-CoV-2. The experimental results showed that acriflavine inhibits the interaction between viral receptor-binding domain (RBD) of spike protein and angiotensin converting enzyme-2 (ACE2) host receptor driving viral cell entry. The prepared ACF@MOF composites exhibited low (MOF-808 and UiO-66) and high (UiO-67 and NU-1000) ACF loadings. The drug release profiles from prepared composites showed different release kinetics depending on the local pore environment. The long-term ACF release with the effective antiviral ACF concentration was observed for all studied ACF@MOF composites. The density functional theory (DFT) calculations allowed us to determine that π–π stacking together with electrostatic interaction plays an important role in acriflavine adsorption and release from ACF@MOF composites. The molecular docking results have shown that acriflavine interacts with several possible binding sites within the RBD and binding site at the RBD/ACE2 interface. The cytotoxicity and ecotoxicity results have confirmed that the prepared ACF@MOF composites may be considered potentially safe for living organisms. The complementary experimental and theoretical results presented in this study have confirmed that the ACF@MOF composites may be considered a potential candidate for the COVID-19 treatment, which makes them good candidates for clinical trials.

Downregulation of topoisomerase 1 and 2 with acriflavine sensitizes bladder cancer cells to cisplatin-based chemotherapy.

Resistance to cisplatin is a major obstacle to effective treatment of bladder cancer (BC). The present study aimed to determine whether a combination of acriflavine (ACF) with cisplatin could potentiate the antitumor property of cisplatin against the BC cells. Furthermore, the molecular mechanism behind the anticancer action of ACF was considered. Two human BC cells (5637 and EJ138) contain mutated form of p53 was culture in standard condition. Cotreatment protocol (simultaneous combination of IC30 value of ACF + various dose of cisplatin for 72h) and pretreatment protocol (pretreatment with IC15 value of ACF for 24h + various dose of cisplatin for 48h) was used to determine the effect of ACF on the cells' sensitivity to main drug cisplatin. To assess the mechanism of action of ACF, real-time PCR was used to evaluate mRNA levels of hypoxia-inducible factor-1α (HIF-1α), Bax, Bcl-2, topoisomerase1 (TOP1) and topoisomerase 2 (TOP2A). Combination of ACF with cisplatin either as cotreatment or opretreatment protocol could significantly reduce the IC50 values of cisplatin as compared to the IC50 of cisplatin when use as a single drug. In addition, ACF could markedly decrease mRNA expression of TOP1 and TOP2A without changing the expression of HIF-1ɑ, Bax and Bcl-2. Our findings indicate that combination of cisplatin with ACF was able to significantly enhance the sensitivity of BC cells to cisplatin. The antitumor activity of ACF is exerted through the downregulation of TOP1 and TOP2A genes expression. ACF may serve as an adjuvant to boost cisplatin-based chemotherapy.

DNA topoisomerase inhibition with the HIF inhibitor acriflavine promotes transcription of lncRNAs in endothelial cells

The transcription factor hypoxia-inducible factor 1 (HIF1) is an important driver of cancer and is therefore an attractive drug target. Acriflavine (ACF) has been suggested to inhibit HIF1, but its mechanism of action is unknown. Here we investigated the interaction of ACF with DNA and long non-coding RNAs (lncRNAs) and its function in human endothelial cells. ACF promoted apoptosis and reduced proliferation, network formation, and angiogenic capacity. It also induced changes in gene expression, as determined by RNA sequencing (RNA-seq), which could not be attributed to specific inhibition of HIF1. A similar response was observed in murine lung endothelial cells. Although ACF increased and decreased a similar number of protein-coding genes, lncRNAs were preferentially upregulated under normoxic and hypoxic conditions. An assay for transposase accessibility with subsequent DNA sequencing (ATAC-seq) demonstrated that ACF induced strong changes in chromatin accessibility at lncRNA promoters. Immunofluorescence showed displacement of DNA:RNA hybrids. Such effects might be due to ACF-mediated topoisomerase inhibition, which was indeed the case, as reflected by DNA unwinding assays. Comparison with other acridine derivatives and topoisomerase inhibitors suggested that the specific function of ACF is an effect of acridinium-class compounds. This study demonstrates that ACF inhibits topoisomerases rather than HIF specifically and that it elicits a unique expression response of lncRNAs.