Furazolidone induced oxidative DNA damage via up-regulating ROS that caused cell cycle arrest in human hepatoma G2 cells

Analysis of Giardia lamblia Nucleolus as Drug Target: A Review

Giardia lamblia (G. lamblia) is the main causative agent of diarrhea worldwide, affecting children and adults alike; in the former, it can be lethal, and in the latter a strong cause of morbidity. Despite being considered a predominant disease in low-income and developing countries, current migratory flows have caused an increase in giardiasis cases in high-income countries. Currently, there is a wide variety of chemotherapeutic treatments to combat this parasitosis, most of which have potentially serious side effects, such as genotoxic, carcinogenic, and teratogenic. The necessity to create novel treatments and discover new therapeutic targets to fight against this illness is evident. The current review centers around the controversial nucleolus of G. lamblia, providing a historical perspective that traces its apparent absence to the present evidence supporting its existence as a subnuclear compartment in this organism. Additionally, possible examples of ncRNAs and proteins ubiquitous to the nucleolus that can be used as targets of different therapeutic strategies are discussed. Finally, some examples of drugs under research that could be effective against G. lamblia are described.

Enhancing catalytic activity through the construction of praseodymium tungstate decorated on hierarchical three-dimensional porous biocarbon for determination of furazolidone in aquatic samples

Boosting catalytic performance as a vital role for an electrochemical sensor for monitoring various hazardous nitro drugs. Herein, an inexpensive, facile, and eco-friendly construction of praseodymium tungstate decorated on three dimensional porous biocarbon (PrW/3D-PBC) for electrochemical determination of carcinogenic residue furazolidone (FZ). The nanostructured PrW nanoparticles were prepared by solvent evaporation from peroxo-tungstic acid and 3D-PBC was prepared from biomass precursor under the carbonization method. Furthermore, the composite of PrW decorated on 3D-PBC was prepared by an ultrasonic-assisted wet chemical approach. Besides, the composite characterization of crystalline, functional group, degree of carbonization, chemical states, and morphology were utilized by theXRD, FTIR, RAMAN, XPS, and FESEM analysis. These 3D porous carbon decorated PrW nanoparticles facilitate the electrochemical anchoring sites, surface area, and ease of diffusion layers towards the detection of hazardous nitro pollutant FZ by using CV analysis. The low LOD and high sensitivity were achieved by FZ determination through using LSV and DPV techniques. The practical capability of the PrW/3D-PBC/GCE sensor was determined by using aquatic samples to achieve a good recovery result. These results instigate that the PrW/3D-PBC will be an efficient electrocatalytic material for FZ sensor in environmental aquatic samples.

A review on nanomaterial-based electrodes for the electrochemical detection of chloramphenicol and furazolidone antibiotics

To grow food for people, antibiotics were used, and these antibiotics can accumulate in the human body through food metabolism, which may have remarkably harmful effects on human health and safety. Therefore, low-cost sensors are needed for the detection of antibiotic residues in food samples. Recently, nanomaterial-based electrochemical sensors such as carbon nanoparticles, graphene nanoparticles, metal oxide nanoparticles, metal nanoparticles, and metal-organic nanostructures have been successfully used as sensing materials for the detection of chloramphenicol (CP) and furazolidone (FZ) antibiotics. However, additional efforts are still needed to fabricate effective multi-functional nanomaterial-based electrodes for the preparation of portable electrochemical sensor devices. The current review focuses on a quick introduction to CP and FZ antibiotics, followed by an outline of the current electrochemical analytical methods. In addition, we have discussed in-depth different nanoparticle supports for the electrochemical detection of CP and FZ in different matrices such as food, environmental, and biological samples. Finally, a summary of the current problems and future perspectives in this area are also highlighted.

Ultrasensitive electrochemical detection of furazolidone in biological samples using 1D-2D BiVO4@MoS2 hierarchical nano-heterojunction composites armed electrodes

In this work, the hydrothermally synthesized of BiVO₄@MoS₂ hierarchical nano-heterojunction composite is employed as a novel electrocatalyst for electrochemical sensing of Furazolidone (FZE) drug by modifying the glassy carbon electrodes (GCE). The Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy are used to thoroughly investigate the functional groups, vibrational modes, crystal structure, elemental composition and surface topography of the heterojunction composite. The physical characterization results revealed the successful construction of 1D-2D BiVO₄@MoS₂ hierarchical nano-heterojunction composite. When these unique architectures are reinforced on GCE surface, we achieved an enhanced electroactive surface area of 0.154 cm². The electrochemical performance of 1D-2D BiVO₄@MoS₂ is examined though cyclic voltammetry and differential pulse voltammetry (DPV) analysis. The BiVO₄@MoS₂ composites exhibited an excellent electrocatalytic activity in sensing of FZE with superior linear detection ranges of 0.01-14 and 14-614 μM. The limit of detection (LOD) of the BiVO₄@MoS₂ based sensor is determined to be 2.9 nM which is far superior than other reported FZE sensors. Consequently, it is evident from the investigation that the BiVO₄@MoS₂ based FZE sensor can be recommended for analyzing real time samples like human urine and blood serum with appreciable recovery.

Akt activation-dependent protective effect of wild ginseng adventitious root protein against UVA-induced NIH-3T3 cell damage

Prolonged skin exposure to ultraviolet radiation can lead to development of several acute and chronic diseases, with UVA exposure considered a primary cause of dermal photodamage. We prepared a wild ginseng adventitious root extract (ARE) that could alleviate UVA irradiation-induced NIH-3T3 cell viability decline. After employing a series of purification methods to isolate main active components of ARE, adventitious root protein mixture (ARP) was identified then tested for protective effects against UVA irradiation-induced NIH-3T3 cell damage. The results showed that ARP treatment significantly reduced UVA-induced cell viability decline and confirmed that the active constituent of ARP was the protein, since proteolytic hydrolysis and heat treatment each eliminated ARP protective activity. Moreover, ARP treatment markedly inhibited UVA-induced apoptosis, cell cycle arrest and DNA fragmentation, while also significantly reversing UVA effects (elevated Bax levels, reduced Bcl-2 expression) by reducing Bax levels and increasing Bcl-2 expression. Mechanistically, ARP promoted Akt phosphorylation regardless of UVA exposure, thus confirming ARP resistance to inactivation by UVA light. Notably, in the presence of Akt inhibitor SC0227, ARP could no longer counteract UVA-induced cell viability decline and DNA fragmentation. Additionally, our results demonstrated that ARP treatment protected UVA-irradiated NIH-3T3 cells by preventing UVA-induced reduction of collagen-I expression. Taken together, these results suggest that ARP treatment of NIH-3T3 cells effectively mitigated UVA-induced cell viability decline by activating intracellular Akt to reduce UVA-induced DNA damage, leading to reduced rates of apoptosis and cell cycle arrest after UVA exposure and restoring collagen expression to normal levels.

Inhibition of aldehyde dehydrogenase by furazolidone nanoemulsion to decrease cisplatin resistance in lung cancer cells

Aim: The overexpression of aldehyde dehydrogenase (ALDH) in cancer cells contributes to therapeutic resistance. Furazolidone (FUR) is a strong ALDH inhibitor. Methods: FUR nanoemulsion (NE) was formulated and tested for ALDH inhibitory activity in comparison with free FUR. The cytotoxic potential of cisplatin was evaluated in combination with free FUR and FUR NE. Results: The optimized FUR NE showed droplet size of 167.9 ± 3.1 nm and drug content of 84.2 ± 2.3%. FUR NE inhibited 99.75 ± 2.1% of ALDH activity while 25.0 ± 4.6% was inhibited by free FUR. FUR NE increased the sensitivity to cisplatin in A549 cells by more than tenfold by its ALDH inhibitory effects. Conclusion: This finding can be a promising approach to improve cancer survival in ALDH-positive drug-resistant cancers.

MOF-derived hollow NiCo2O4/C composite for simultaneous electrochemical determination of furazolidone and chloramphenicol in milk and honey

Herein, bimetallic Co/Ni-MOF derived hollow NiCo₂O₄@C composite modified glassy carbon electrode (NiCo₂O₄@C/GCE) is constructed and applied to simultaneously detect furazolidone (FZD) and chloramphenicol (CAP) for the first time. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, nitrogen adsorption-desorption and X-ray photoelectron spectroscopy confirm that NiCo₂O₄@C has hollow and mesoporous structure, abundant carbon matrixes, sufficient oxygen defects and mixed-valence metallic elements. These advantages make NiCo₂O₄@C/GCE show distinguished electrocatalytic performance toward the simultaneous determination of FZD and CAP. The NiCo₂O₄@C/GCE shows wide linear ranges of 0.5-240 µM for FZD and 0.5-320 µM for CAP, low limit of detection of 8.47 nM for FZD and 35 nM for CAP. The mechanism studies show that reductions of FZD and CAP on NiCo₂O₄@C/GCE are both four-electron and four-proton processes. Moreover, the sensor obtains desirable recoveries for the simultaneous determination of FZD (95.85%-103.9%) and CAP (95.72%-104.4%) in milk and honey by standard addition method.

Human/eukaryotic ribosomal protein L14 (RPL14/eL14) overexpression represses proliferation, migration, invasion and EMT process in nasopharyngeal carcinoma

Although human/eukaryotic ribosomal protein L14 (RPL14/eL14) is known to be associated with a variety of cancers, its role in nasopharyngeal carcinoma (NPC) remains unclear. The aim of this study was to explore the impact of RPL14(eL14) in NPC. The results of quantitative real-time polymerase chain reaction (qRT-PCR), western blot, and immunohistochemical staining revealed that the expression of RPL14(eL14) significantly reduced in NPC tissues and cells. Furthermore, the protein expression of RPL14(eL14) was linked to NPC-related clinical pathological features, including the T and N classification of Tumor Node Metastasis (TNM) staging (all p < 0.05). Cell counting kit-8 (CCK-8) assay and colony formation assay revealed that RPL14(eL14) overexpression repressed NPC cell proliferation. In cell cycle assay, RPL14(eL14) overexpression significantly blocked NPC cells in S phase. Overexpression of RPL14(eL14) repressed cell migration and invasion in NPC as shown by transwell assay and cell scratch healing assay. In addition, RPL14(eL14) was closely correlated with the expression of epithelial–mesenchymal transition (EMT) biomarkers, including E-cadherin, N-cadherin, and vimentin as detected by western blot. In conclusion, our results revealed that RPL14(eL14) may be considered as an antioncogene in NPC, which greatly suppresses cancer progression.

Development and Validation of a LC-MS/MS Method for the Determination of Nitrofuran Metabolites in Soft-Shell Turtle Powder Health Food Supplement

Soft-shell turtle (SST; freshwater terrapin or tortoise) is a popular and important health functional food (HFF) product in many Asian countries. HFFs containing SST must be safe, but several HFFs have been found to be contaminated with dangerous substances, such as nitrofuran metabolites (NFMs). This finding suggests that the consumption of HFFs results in the regular exposure of vulnerable individuals to hazardous substances. Importantly, nitrofuran antibiotics have been banned for use in food-producing animals since the 1990s by the European Union. Thus, in this study, we propose a reliable and quick method to reduce the time required for the detection of four NFMs in SST powder that conventional methods are unable to quantify. Our method involves the derivatization and hydrolysis of SST powder and was validated in accordance with the requirements of European Commission Decision 2002/657/EC. The method achieves an apparent mean recovery of 82.2–108.1%, repeatability of 1.5–3.8%, and reproducibility of 2.2–4.8% for 0.5–10.0 μg kg⁻¹ of 1-aminohydantoin, semicarbazide, 3-amino-2-oxazolidinone, and 3-amino-5-morpholinomethyl-2-oxazolidinone. In addition, linearity was achieved with correlation coefficients of 0.999, and the detection capability (CCβ) and decision limit (CCα) were found to be reliable, indicating that this is a fast and accurate method for the analysis of SST powder. The validated method was successfully applied to detect NFMs in SST powder in commercial HHFs.

A simplified modification to rapidly determine the residues of nitrofurans and their metabolites in aquatic animals by HPLC triple quadrupole mass spectrometry

A simplified method is described for reducing the analysis time of nitrofurans (NFs) and nitrofuran metabolites (NFMs) in the aquatic animals. Most existing HPLC-MS/MS methods are intended only for NFMs and are based on their fast metabolic transformations. We optimized a method for simultaneously detecting major NFs and their metabolites, including nitrovin (NV) that imply use of an optimized buffer solution. The novel method was validated by six different aquatic animal matrices (loach, catfish, shrimp, lobster, scallop, and eel) spiked with the analytes at 0.5, 1.0, and 2.0 μg kg^-1. Recovery rates and %RSDs (relative standard deviations) of 82-97% and 1-8% were observed for NFMs, respectively, with values of 70-96% and 1-8% obtained for furazolidone, furaltadone, nitrofurazone, nitrofurantoin, and NV, respectively. Linearity was observed in the 0.1-20 μg L^-1 range, with correlation coefficients greater than 0.99 recorded for all compounds. The developed method is sensitive, accurate, easier to use, and faster than previous methods when applied to real samples. To the best of our knowledge, this is the first method that can simultaneously determine NFs and their metabolites, as well as NV, using a single-step extraction process.

Gold Nanoparticle Embedded on a Reduced Graphene Oxide/polypyrrole Nanocomposite: Voltammetric Sensing of Furazolidone and Flutamide

A new electrochemical sensor has been constructed based on the in situ preparation of gold nanoparticle embedded on reduced graphene oxide and polypyrrole nanotube (AuNP@rGO/PPyNT) composite through a nanosecond laser-induced heating technique. The as-prepared composite is used for individual as well as the simultaneous electrochemical determination of chemotherapy drug (furazolidone, FU) and anticancer drug (flutamide, FLT). The composite was analyzed by X-ray Diffraction, scanning electron microscopy/energy-dispersive X-ray analysis, transmission electron microscopy, Raman spectrometry, and X-ray photoelectron spectroscopy analysis, thus confirming the successful synthesis of this composite and its physical features. The modified AuNP@rGO/PPyNT electrode was examined through cyclic voltammetry and differential pulse voltammetry (DPV) methods in pH 7.0 for the determination of FU and FLT in individual, simultaneous, and mixed systems. The fabricated sensor showed wide linear responses (0.01-1080.11 μM and 0.01-1214.11 μM) of analytes, with the lower limits of detection of 2.3 and 2.45 nM and higher sensitivity of 53.75 and 50.06 μA μM^-1 cm^-2, respectively. Furthermore, the constructed sensor demonstrates higher stability, reproducibility, and repeatability, and is effectively applied for the analysis of FU and FLT content in the human serum sample analysis with satisfactory recovery.

Toxicity assessment of the herbicide acetochlor in the human liver carcinoma (HepG2) cell line

Acetochlor is a high-volume herbicide used on a global scale and toxicity assessments are needed to define its potential for adverse effects in wildlife and humans. This study was conducted to determine the effects of acetochlor on human liver carcinoma cells (HepG2), a cell model widely used to assess the potential for chemical hepatotoxicity. Experiments were conducted at concentrations ranging 0-800 μM acetochlor over a 12 to 48h period to quantify underlying mechanisms of toxicity. Our data indicate that acetochlor suppressed HepG2 cell proliferation in both a concentration- and time-dependent manner. Acetochlor induced reactive oxygen species (ROS) generation more than 700% with exposure to 400 μM acetochlor, and acetochlor decreased the activities and levels of anti-oxidant responses (superoxide dismutase, glutathione) following exposure to 100 μM, 200 μM and 400 μM acetochlor. Acetochlor also (1) induced HepG2 cell damage through apoptotic-signaling pathways; (2) enhanced intracellular free Ca²⁺ concentration (>400%); (3) decreased mitochondrial transmembrane potential (∼77%), and reduced ATP levels (∼65%) following exposure to 400 μM acetochlor compared to untreated cells. Notably, cell cycle progression was blocked at G0/G1 phase in HepG2 cells when treated for 24 h with 400 μM acetochlor. Taken together, acetochlor induced significant cytotoxicity toward HepG2 cells, and the underlying toxicity mechanisms appear to be related to ROS generation, mitochondrial dysfunction and disruption in the cell cycle regulation. These data contribute to toxicity assessments for acetochlor, a high-use herbicide, to quantify risk to wildlife and human health.

Alternative eradication regimens for Helicobacter pylori infection in Indonesian regions with high metronidazole and levofloxacin resistance

Background

The prevalence of Helicobacter pylori resistance to metronidazole and clarithromycin is high in Indonesia. Moreover, the increasing levofloxacin resistance rates in the absence of bismuth treatment in Indonesia has led to the use of other antibiotics as alternative regimens.

Methods

We determined the minimum inhibitory concentrations (MICs) of five alternative antibiotics for H. pylori (rifaximin, rifabutin, furazolidone, garenoxacin, and sitafloxacin) using the agar dilution method and assessed mutations associated with antibiotic resistance using next-generation sequencing.

Result

Analysis of 106 strains isolated from 1039 adult dyspeptic patients revealed that none of the strains were furazolidone-resistant. All strains were also sensitive to rifabutin and sitafloxacin. In contrast, the rates of resistance to rifaximin and garenoxacin were high (38.9% and 6.7%, respectively). The strains isolated from patients on Java Island had the highest resistance rates to garenoxacin and rifaximin. In addition, the resistance was distributed evenly among the ethnic groups, ranging between 25.0% and 69.2%. Except for rifaximin, for which the resistance rate was 38.9%, the other four antibiotics could be successfully employed to eradicate levofloxacin- and metronidazole-resistant H. pylori infections in vitro. Interestingly, garenoxacin-sensitive strains were found in regions with high clarithromycin resistance rates such as Bali and Papua Islands. In contrast, rifaximin might not be considered as an alternative antibiotic in regions with high clarithromycin resistance. There was an inconsistent association between gyrA and gyrB mutations and garenoxacin resistance. We confirmed that the I837V (replacement of isoleucine at position 837 with valine), A2414T/V, Q2079K and K2068R were the predominant rpoB point mutations. There was an association between vacA genotypes of H. pylori and rifaximin resistance (P = 0.048).

Conclusion

furazolidone-, rifabutin-, and sitafloxacin-based therapies might be considered as alternative regimens to eradicate H. pylori in Indonesia, including regions with high metronidazole and clarithromycin resistance rates. Moreover, sitafloxacin but not garenoxacin should be considered for eradication of levofloxacin-resistant strains.

Outcomes of furazolidone- and amoxicillin-based quadruple therapy for Helicobacter pylori infection and predictors of failed eradication

AIM

To evaluate the outcomes of furazolidone- and amoxicillin-based quadruple therapy for treatment of Helicobacter pylori (H. pylori) infection and identify predictors of failed eradication.

METHODS

Patients with H. pylori infection treated with furazolidone, amoxicillin, bismuth, and proton pump inhibitor therapy (January 2015 to December 2015) who received the ¹³C-urea breath test > 4 wk after treatment were evaluated. Demographic and clinical data including prior H. pylori treatment attempts, medication adherence, alcohol and cigarette consumption during therapy, and treatment-related adverse events were recorded by reviewing medical records and telephone surveys. H. pylori eradication rates for overall and subgroups were evaluated. Multivariate analysis was performed to identify independent predictors of failed H. pylori eradication.

RESULTS

Of the 992 patients treated and retested for H. pylori infection, the overall eradication rate was 94.5% [95% confidence interval (CI): 94.1%-95.9%]. H. pylori eradication rate of primary therapy was 95.0% (95%CI: 93.5%-96.5%), while that of rescue therapy was 91.3% (95%CI: 86.8%-95.8%). Among the 859 patients who completed the study protocol, 144 (17%) reported treatment-related adverse events including 24 (3%) leading to premature discontinuation. On multivariate analysis, poor medication adherence [adjusted odds ratio (AOR) = 6.7, 95%CI: 2.8-15.8], two or more previous H. pylori treatments (AOR = 7.4, 95%CI: 2.2-24.9), alcohol consumption during therapy (AOR = 4.4, 95%CI: 1.5-12.3), and possibly smoking during therapy (AOR = 1.9, 95%CI: 0.9-4.3) were associated with failed H. pylori eradication.

CONCLUSION

Furazolidone- and amoxicillin-based quadruple therapy for H. pylori infection in an area with a high prevalence of clarithromycin resistance demonstrated high eradication rates as primary and rescue therapies with a favorable safety profile. Patient education targeting abstinence from alcohol during therapy and strict medication adherence may further optimize H. pylori eradication.

In vitro screening of cell bioenergetics to assess mitochondrial dysfunction in drug development

Drug-induced mitochondrial toxicity is considered as a common cellular mechanism that can induce a variety of organ toxicities. In the present manuscript, 17 in vitro mitochondrial toxic drugs, reported to induce Drug-Induced Liver Injury (DILI) and 6 non-mitochondrial toxic drugs (3 with DILI and 3 without DILI concern), were tested in HepG2 cells using a bioenergetics system. The 17 mitochondrial toxic drugs represent a wide variety of mitochondrial dysfunctions as well as DILI and include 4 pairs of drugs which are structurally related but associated with different DILI concerns in human. Cell bioenergetics were measured using the XF96e analyzer which simultaneous monitor oxygen consumption rate (OCR) and extracellular acidification rate (ECAR), indirect measurements of oxidative phosphorylation and glycolysis, respectively. OCR associated with ATP production, maximal respiration, proton leak and spare respiratory capacity, were also assessed. Duplicate experiments resulted in a sensitivity of 82% (14/17) and specificity of 83% (5/6). The addition of stressors improved specificity considerably. Cut-offs, statistics and rules are clearly discussed to facilitate the use of this assay for screening purposes. Overall, the authors consider that this assay should be part of the battery of safety screening assays at early stages of drug development.

Alterations of antioxidant indexes and inflammatory cytokine expression aggravated hepatocellular apoptosis through mitochondrial and death receptor-dependent pathways in Gallus gallus exposed to arsenic and copper

In this study, we sought to investigate the effects of sub-chronic exposure of arsenic (As) and copper (Cu) on oxidative stress, inflammatory response, and mitochondria and death receptor apoptosis pathways in chicken liver. Seventy-two 1-day-old male Hy-line chickens were treated with basal diet, 30 mg/kg arsenic trioxide (As₂O₃), or/and 300 mg/kg copper sulfate (CuSO₄) for 4, 8, and 12 weeks. Study revealed that exposure to As or/and Cu undermined the antioxidant function and increased lipid peroxidation. Worse yet, liver cell swollen, vacuolar degeneration, and inflammatory cell infiltration were accompanied by an increase of the nuclear factor-κB (NF-κB) and its downstream inflammation-related genes after exposure to As or/and Cu. Furthermore, mitochondria swollen and chromatin condensation were found in As and Cu groups, and hepatocyte nuclear membrane rupture and markedly increased (P < 0.01) apoptosis index were observed in As combined with Cu group. Meanwhile, the transcription and protein expression levels of Bcl-2-associated X protein (Bax), p53, cytochrome c (Cyt c), and caspase-3, 8, 9 were upregulated and B cell lymphoma-2 (Bcl-2) was downregulated in As, Cu, and As + Cu groups in the liver tissues (P < 0.05, P < 0.01). Our results indicated that exposure to As or/and Cu could lead to oxidative stress, inflammatory response, and tissue damage and aggravate hepatocellular apoptosis through mitochondrial and death receptor-dependent pathways in chicken liver. And As and Cu showed a possible synergistic relationship in liver damage.

Highly potent host external immunity acts as a strong selective force enhancing rapid parasite virulence evolution

Virulence is often under selection during host-parasite coevolution. In order to increase fitness, parasites are predicted to circumvent and overcome host immunity. A particular challenge for pathogens are external immune systems, chemical defence systems comprised of potent antimicrobial compounds released by prospective hosts into the environment. We carried out an evolution experiment, allowing for coevolution to occur, with the entomopathogenic fungus, Beauveria bassiana, and the red flour beetle, Tribolium castaneum, which has a well-documented external immune system with strong inhibitory effects against B. bassiana. After just seven transfers of experimental evolution we saw a significant increase in parasite induced host mortality, a proxy for virulence, in all B. bassiana lines. This apparent virulence increase was mainly the result of the B. bassiana lines evolving resistance to the beetles' external immune defences, not due to increased production of toxins or other harmful substances. Transcriptomic analyses of evolved B. bassiana implicated the up-regulation of oxidative stress resistance genes in the observed resistance to external immunity. It was concluded that external immunity acts as a powerful selective force for virulence evolution, with an increase in virulence being achieved apparently entirely by overcoming these defences, most likely due to elevated oxidative stress resistance.

Physiological oxygen tension reduces hepatocyte dedifferentiation in in vitro culture

Primary hepatocytes cultured in vitro are a powerful tool to study the functions of hepatocytes and to evaluate the metabolism and toxicity of new drugs. However, in vitro culture of hepatocytes has proven to be very difficult. Ordinary culture conditions lead to dedifferentiation of hepatocytes, resulting in rapid change in cell morphology and significant reduction in specific cell functions. In the current study, we show that hepatocyte dedifferentiation is a rapid process under 21% O₂ conditions. Hepatocytes cultured in 21% O₂ undergo epithelial-to-mesenchymal transition (EMT), obtain fibroblast-like morphology, and show decreased hepatic functions. In contrast, 5% O₂ is very effective in maintaining the epithelial morphology and many functions of the primary hepatocytes cultured in vitro for up to five days. These functions include albumin production, glycogen storage, LDL-uptake and CYP450-mediated drug metabolism. Furthermore, we find that 5% O₂ can relieve the production of reactive oxygen species (ROS) and decrease the level of DNA damage in primary cultured hepatocytes. In addition, we also show that blocking the ERK and GSK-3β pathways can inhibit the dedifferentiation of hepatocytes to a certain extent. Lowering the oxygen tension in cell culture is easily achievable, we believe it could be combined with other methods, such as the use of small molecule cocktails and 3D culture, to maintain proliferation and functions of primary hepatocytes in vitro.

GADD45a Regulates Olaquindox-Induced DNA Damage and S-Phase Arrest in Human Hepatoma G2 Cells via JNK/p38 Pathways

Olaquindox, a quinoxaline 1,4-dioxide derivative, is widely used as a feed additive in many countries. The potential genotoxicity of olaquindox, hence, is of concern. However, the proper mechanism of toxicity was unclear. The aim of the present study was to investigate the effect of growth arrest and DNA damage 45 alpha (GADD45a) on olaquindox-induced DNA damage and cell cycle arrest in HepG2 cells. The results showed that olaquindox could induce reactive oxygen species (ROS)-mediated DNA damage and S-phase arrest, where increases of GADD45a, cyclin A, Cdk 2, p21 and p53 protein expression, decrease of cyclin D1 and the activation of phosphorylation-c-Jun N-terminal kinases (p-JNK), phosphorylation-p38 (p-p38) and phosphorylation-extracellular signal-regulated kinases (p-ERK) were involved. However, GADD45a knockdown cells treated with olaquindox could significantly decrease cell viability, exacerbate DNA damage and increase S-phase arrest, associated with the marked activation of p-JNK, p-p38, but not p-ERK. Furthermore, SP600125 and SB203580 aggravated olaquindox-induced DNA damage and S-phase arrest, suppressed the expression of GADD45a. Taken together, these findings revealed that GADD45a played a protective role in olaquindox treatment and JNK/p38 pathways may partly contribute to GADD45a regulated olaquindox-induced DNA damage and S-phase arrest. Our findings increase the understanding on the molecular mechanisms of olaquindox.

Involvement of the activation of Nrf2/HO-1, p38 MAPK signaling pathways and endoplasmic reticulum stress in furazolidone induced cytotoxicity and S phase arrest in human hepatocyte L02 cells: modulation of curcumin

Furazolidone (FZD) is extensively used as the antiprotozoal and antibacterial drug in clinic. The previous study has shown that curcumin pretreatment could improve FZD induced cytotoxicity by inhibiting oxidative stress and mitochondrial apoptotic pathway. The current study aimed to investigate the potential roles of endoplasmic reticulum (ER) stress, p38 mitogen-activated protein kinases (p38 MAPK) signaling pathway in curcumin against FZD cytotoxicity by using human hepatocyte L02 cells. The results showed that curcumin could markedly attenuate FZD induced cytotoxicity. Compared with FZD alone group, curcumin pretreatment significantly reduced the expression of phospho (p)-p38, cyclin D1, p-checkpoint kinase 1 (ChK1) and breast cancer associated gene 1 (BRCA1) protein, followed to attenuate S phase arrest. Meanwhile, curcumin pretreatment prevented FZD induced ER stress, evidenced by the inhibition of glucose-regulated protein 78 and DNA damage inducible gene 153/C/EBP-homologous protein (GADD153/CHOP) protein expression. Moreover, compared with the control, FZD exposure activated the protein and mRNA expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1), which were further activated by curcumin treatment. These results reveal that curcumin could prevent FZD induced cytotoxicity and S phase arrest, which may involve the activation of Nrf2/HO-1 pathway and the inhibition of p38 MAPK pathway and ER stress.

Delamanid is not metabolized by Salmonella or human nitroreductases: A possible mechanism for the lack of mutagenicity

Nitro-containing compounds such as nitrofuran and nitroimidazole are drugs used for the treatment of infectious diseases. However, many of these nitro-containing drugs are positive in the bacterial reverse mutation assay (Ames test). The recently approved anti-multidrug-resistant tuberculosis (MDR-TB) drug, delamanid (Deltyba™; OPC-67683), a derivative of 4-nitroimidazole, was negative for mutagenicity in the Ames assay. In Salmonella typhimurium, mutagenicity of nitro compounds has been closely associated with the ability of nitroreductase to metabolize (degradation)these compounds. To explore the lack of mutagenicity for delamanid, we examined the initial metabolic rate and mutagenic-specific activity of a series of nitro compounds in S. typhimurium TA100. The order of maximum mutagenic-activity was nitrofuran > 2-nitroimidazole > 5-nitroimidazole ≥ 4-nitroimidazole, which is very similar to the order of initial metabolic rate, i.e., the Pearson's correlation coefficient (r = 0.85) showed a correlation between metabolic rate and mutagenic-activity. No metabolism of delamanid was detected even after 60 h of treatment. In addition, delamanid was not reduced by two human nitroreductases. These facts may explain the absence of genotoxicity of delamanid in both in vitro and in vivo tests.

Histomonosis in poultry: previous and current strategies for prevention and therapy

Histomonosis is a parasitic disease of poultry with worldwide prevalence. The disease can cause morbidity and mortality in chicken and turkey flocks entailing severe economic losses. In the first half of the last century, there was a high demand to control histomonosis as the turkey industry was severely affected by the disease. Consequently, numerous chemical compounds were tested for their efficacy against Histomonas meleagridis with varying outcomes, that are summarized and specified in this review. At the same time, preliminary attempts to protect birds with cultured histomonads indicated the possibility of vaccination. Several years ago antihistomonal drugs were banned in countries with tight regulations on pharmaceuticals in order to comply with the demand of consumer protection. As a consequence, outbreaks of histomonosis in poultry flocks increased and the disease became endemic again. New approaches to prevent and treat histomonosis are, therefore, needed and recently performed studies focused on various areas to combat the disease, from alternative chemotherapeutic substances to plant-derived compounds until vaccination, altogether reviewed here. Considering existing regulations and the overall outcome of experimental studies, it can be concluded that vaccination is very promising, despite the fact that various challenges need to be addressed until the first ever developed vaccine based upon live flagellates in human or bird medicine can be marketed.

Curcumin Ameliorates Furazolidone-Induced DNA Damage and Apoptosis in Human Hepatocyte L02 Cells by Inhibiting ROS Production and Mitochondrial Pathway

Furazolidone (FZD), a synthetic nitrofuran derivative, has been widely used as an antibacterial and antiprotozoal agent. Recently, the potential toxicity of FZD has raised concerns, but its mechanism is still unclear. This study aimed to investigate the protective effect of curcumin on FZD-induced cytotoxicity and the underlying mechanism in human hepatocyte L02 cells. The results showed that curcumin pre-treatment significantly ameliorated FZD-induced oxidative stress, characterized by decreased reactive oxygen species (ROS) and malondialdehyde formation, and increased superoxide dismutase, catalase activities and glutathione contents. In addition, curcumin pre-treatment significantly ameliorated the loss of mitochondrial membrane potential, the activations of caspase-9 and -3, and apoptosis caused by FZD. Alkaline comet assay showed that curcumin markedly reduced FZD-induced DNA damage in a dose-dependent manner. Curcumin pre-treatment consistently and markedly down-regulated the mRNA expression levels of p53, Bax, caspase-9 and -3 and up-regulated the mRNA expression level of Bcl-2. Taken together, these results reveal that curcumin protects against FZD-induced DNA damage and apoptosis by inhibiting oxidative stress and mitochondrial pathway. Our study indicated that curcumin may be a promising combiner with FZD to reduce FZD-related toxicity in clinical applications.

iRGD-mediated reduction-responsive DSPE–PEG/LA–PLGA–TPGS mixed micelles used in the targeted delivery and triggered release of docetaxel in cancer

Reduction-sensitive micelles with crosslinked cores were developed to load the lipophilic chemotherapeutic drug docetaxel (DTX) in order to overcome the issues of toxicity, water insolubility, and rapid metabolism of DTX.

Review: clinical management of Helicobacter pylori infection in China

Helicobacter pylori (H. pylori) infection has been associated with gastric disorders. The situation of H. pylori infection in China-where a high prevalence of H. pylori infection, a high incidence of gastric cancer, and widespread resistance to clarithromycin, metronidazole, and levofloxacin exist-is quite different from that in Western countries. In order for Chinese clinicians to better manage H. pylori infection, a Chinese Study Group on H. pylori published four consensus reports regarding the management of H. pylori infection in China between 1999 and 2012. The eradication rate with standard triple therapy was <80% in most areas of China. Bismuth is available in China, and bismuth-containing quadruple therapy has been shown to produce a high eradication rate; thus, bismuth quadruple therapy could be recommended both as an initial and as a rescue therapy in China. There is no advantage of sequential therapy over triple therapy in Chinese patients, but the efficacy of concomitant therapy must be studied further. This review introduces the epidemiology, diagnosis, indicators, and therapies for the eradication of H. pylori in China in recent years.

Levofloxacin and furazolidone induced toxic epidermal necrosis

Toxic epidermal necrolysis (TEN), also known as Lyell's syndrome, is a severe cutaneous drug reaction with a high mortality. Immune response is the possible cause in its pathogenesis. Levofloxacin is one of the most commonly used quinolones and has been reported to cause of TEN. On the other hand, furazolidone was proposed to augment the action of immediate hypersensitivity of levofloxacin by its cytotoxic effect and by the generation of free radicals. Here, we present a case of TEN where, levofloxacin and furazolidone were the probable cause of these adverse drug reactions.

Enhancing the antitumor activity of berberine hydrochloride by solid lipid nanoparticle encapsulation

Berberine hydrochloride (BH) is an isoquinolin alkaloid with promising anticancer efficacies. Nevertheless, further development and application of this compound had been hampered by its poor aqueous solubility, low gastrointestinal absorption, and rapid metabolism in the body. In this study, a solid lipid nanoparticle (SLN)-based system was developed for efficient incorporation and persistent release of BH. The drug-loading SLNs (BH-loaded SLNs) were stable, with a mean particle size of 81.42 ± 8.48 nm and zeta potential of -28.67 ± 0.71 mV. BH-loaded SLNs showed desirable drug entrapment efficiency and drug-loaded, and the release of BH from SLNs was significantly slower than free BH. Importantly, our in vitro study indicated that BH-loaded SLNs more significantly inhibited cell proliferation on MCF-7, HepG 2, and A549 cancer cells. Meanwhile, clone formation, cellular uptake, cell cycle arrest, and cell apoptosis studies also demonstrated that BH-loaded SLNs enhanced the antitumor efficacies of BH on MCF-7 cancer cells. Taken together, our results suggest that this SLN formulation may serve as a novel, simple, and efficient system for the delivery of BH.

The toxicity of nitrofuran compounds on melanoma and neuroblastoma cells is enhanced by Olaparib and ameliorated by melanin pigment

Nitrofurans are commonly used for the treatment of trypanosomal diseases including Chagas disease. More recently, following the fortuitous discovery that nifurtimox was clinically active against neuroblastoma, nitrofuran compounds are being investigated for activity against cancer. Herein, we show that nitrofuran compounds are similarly potent to human malignant melanoma and neuroblastoma cells. Furthermore, a recently discovered nitrofuran compound, NFN1, was 50- to 175-fold more potent than nifurtimox against human melanoma and neuroblastoma cell lines. As nitrofuran compounds are known to act as pro-drugs, producing DNA-damaging reactive intermediates upon activation, we investigated the DNA repair pathways involved. We show that, contrary to research in Escherichia coli, the Nucleotide Excision Repair pathway is not required to repair nitrofuran-induced DNA damage in mammalian cells. Instead, we show that inhibiting repair of single-strand DNA breaks with the poly(ADP-ribose) polymerase (PARP) inhibitor, Olaparib, enhances nitrofuran toxicity in melanoma and neuroblastoma cells. We propose that this is due to mammalian cells utilising Type 2 nitroreductases for nitrofuran activation producing Reactive Oxygen Species which cause DNA damage that is repaired by the Single Strand Break Repair and/or Base Excision Repair pathways, whereas in bacteria and trypanosomes, Type 1 nitroreductases are also utilised resulting in different DNA lesions. In addition we show that, consistent with Reactive Oxygen Species being formed upon nitrofuran activation and the ability of melanin to absorb Reactive Oxygen Species, production of melanin in melanoma cells offers some protection from NFN1- and hydrogen peroxide-induced toxicity. Our data suggest that combinations of Olaparib and nitrofuran compounds may be advantageous for the treatment of melanoma and neuroblastoma, but that the protection offered to melanoma cells by their melanin pigment must be taken into account.

A novel application of furazolidone: anti-leukemic activity in acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common malignant myeloid disorder of progenitor cells in myeloid hematopoiesis and exemplifies a genetically heterogeneous disease. The patients with AML also show a heterogeneous response to therapy. Although all-trans retinoic acid (ATRA) has been successfully introduced to treat acute promyelocytic leukemia (APL), it is rather ineffective in non-APL AML. In our present study, 1200 off-patent marketed drugs and natural compounds that have been approved by the Food and Drug Administration (FDA) were screened for anti-leukemia activity using the retrovirus transduction/transformation assay (RTTA). Furazolidone (FZD) was shown to inhibit bone marrow transformation mediated by several leukemia fusion proteins, including AML1-ETO. Furazolidone has been used in the treatment of certain bacterial and protozoan infections in human and animals for more than sixty years. We investigated the anti-leukemic activity of FZD in a series of AML cells. FZD displayed potent antiproliferative properties at submicromolar concentrations and induced apoptosis in AML cell lines. Importantly, FZD treatment of certain AML cells induced myeloid cell differentiation by morphology and flow cytometry for CD11b expression. Furthermore, FZD treatment resulted in increased stability of tumor suppressor p53 protein in AML cells. Our in vitro results suggest furazolidone as a novel therapeutic strategy in AML patients.

Pyoverdine secreted by Pseudomonas aeruginosa as a biological recognition element for the fluorescent detection of furazolidone

Methods for the rapid and sensitive detection of furazolidone, a pesticide used for the treatment of infections of animals and human beings, have been urgently recommended for its large residual, strong carcinogenicity and genotoxicity in the environment. In this study, a method for the detection of furazolidone based on the rapid fluorescence quenching of pyoverdine by furazolidone was developed. Pyoverdine secreted by a Pseudomonas aeruginosa strain PA1 was purified through affinity chromatography and its fluorescent property was characterized. The fluorescence of pyoverdine could be quenched by furazolidone with specificity, and based on this phenomenon a fluorescent method for furazolidone detection was established. Fluorescence of pyoverdine was quenched by furazolidone probably due to the electron transfer from pyoverdine to furazolidone. The optimal pH for the detection was 7.2 in 50 mM 3-(N-Morpholino) propanesulfonic acid solution, and the whole detection process could be completed within a few seconds. The linear range of the detection was 2-160 µM and the limit of detection (LOD) was 0.5 µM. This study developed a novel fluorescent method for furazolidone detection, and the rapid and specific fluorescent biosensor can be potentially applied for furazolidone detection in the aquatic samples.

Antimicrobial resistance in Shigella spp. causing traveller's diarrhoea (1995-2010): a retrospective analysis

BACKGROUND

Shigellosis is a global human health problem causing an important morbidity among travellers returning from tropical areas. This study was aimed to describe the evolution of antimicrobial resistance profile in Shigella spp. isolated between the years 1995-2010 in patients with traveller's diarrhoea (TD) returning from tropical areas.

METHODS

The levels of antimicrobial resistance were tested in a total of 191 Shigella spp. isolated during the period from 1995 to 2010.

RESULTS

A decrease of cases of diarrhoea caused by Shigella has been observed in recent years. A wide spectrum of antibiotic resistance was observed among Shigella spp. These isolates showed high levels of resistance to tetracycline (84%), co-trimoxazole (75.5%), and ampicillin (45.5%). The resistance was low to ciprofloxacin (2.1%), azithromycin (3.9%) and furazolidone (8.4%). According to the period, in the case of ampicillin, amoxicillin plus clavulanic acid, chloramphenicol, values of resistance were significantly decreasing from 1995-2000 to 2001-2010, (62.5% vs. 28.4%, 19.8% vs. 6.6%, 23.4 vs. 10.4%, respectively). Meanwhile in nalidixic acid and tetracycline the evolution of resistance has increased over time.

CONCLUSIONS

A decrease in the isolation number of Shigella spp. causing TD has been observed. Differential trends in the evolution of the levels of resistance to the tested antibacterial agents have been observed.

Oxidative DNA damage is involved in ochratoxin A-induced G2 arrest through ataxia telangiectasia-mutated (ATM) pathways in human gastric epithelium GES-1 cells in vitro

Ochratoxin A (OTA), one of the most abundant mycotoxin food contaminants, is classified as "possibly carcinogenic to humans." Our previous study showed that OTA could induce a G2 arrest in immortalized human gastric epithelium cells (GES-1). To explore the putative roles of oxidative DNA damage and the ataxia telangiectasia-mutated (ATM) pathways on the OTA-induced G2 arrest, the current study systematically evaluated the roles of reactive oxygen species (ROS) production, DNA damage, and ATM-dependent pathway activation on the OTA-induced G2 phase arrest in GES-1 cells. The results showed that OTA exposure elevated intracellular ROS production, which directly induced DNA damage and increased the levels of 8-OHdG and DNA double-strand breaks (DSBs). In addition, it was found that OTA treatment induced the phosphorylation of the ATM protein, as well as its downstream molecules Chk2 and p53, in response to DNA DSBs. Inhibition of ATM by the pharmacological inhibitor caffeine or siRNA effectively prevented the activation of ATM-dependent pathways and rescued the G2 arrest elicited by OTA. Finally, pretreatment with the antioxidant N-acetyl-L-cysteine (NAC) reduced the OTA-induced DNA DSBs, ATM phosphorylation, and G2 arrest. In conclusion, the results of this study suggested that OTA-induced oxidative DNA damage triggered the ATM-dependent pathways, which ultimately elicited a G2 arrest in GES-1 cells.

Helicobacter pylori eradication in Western Australia using novel quadruple therapy combinations

BACKGROUND

Helicobacter pylori eradication rates with standard triple therapy are declining worldwide. The optimal management of H. pylori is evolving and new treatment combinations for antibiotic resistant H. pylori strains are required, especially for patients with penicillin allergy.

AIM

To review the effectiveness of alternative antibiotic combinations and necessity of pre-antibiotic sensitivity testing.

METHODS

A total of 310 consecutive patients who had failed at least one course of standard 7-day triple therapy initially prescribed by their physicians were included in this study between year 2007 and 2011. Antibiotics were prescribed based on pre-antibiotic sensitivity tests and, if any, patient's allergy to penicillin.

RESULTS

In 98.7% of the patients' samples, H. pylori was successfully cultured. The proportion resistant to clarithromycin and metronidazole was 94.1% and 67.6% respectively, with 65% resistant to both. For the in-house primary quadruple therapy, with Proton pump inhibitor, Amoxicillin, Rifabutin and Ciprofloxacin (PARC), H. pylori was successfully eradicated in 95.2% of patients. For patients allergic to amoxicillin, an alternative quadruple therapy using Proton pump inhibitor, Bismuth subcitrate, Rifabutin and Ciprofloxacin (PBRC) gave an eradication rate of 94.2%. Patients needing alternative salvage therapy were given novel personalised combinations consisting of bismuth, rifabutin, tetracycline or furazolidone; the eradication rate was 73.8%.

CONCLUSIONS

Patients who present with antibiotic resistant H. pylori can be confidently treated with PARC, PBRC or other personalised salvage therapies. These regimens can be used when treatment options are limited by penicillin allergy. Pre-treatment H. pylori antibiotic sensitivity tests contributed to the high eradication rate in this study.

Involvement of the p38 MAPK signaling pathway in S-phase cell-cycle arrest induced by Furazolidone in human hepatoma G2 cells

Given the previously described essential role for the p38 mitogen-activation protein kinase (p38 MAPK) signaling pathway in human hepatoma G2 cells (HepG2), we undertook the present study to investigate the role of the p38 MAPK signaling pathway in cell-cycle arrest induced by Furazolidone (FZD). The aim of this study was to determine the effects of FZD on HepG2 cells by activating and inhibiting the p38 MAPK signaling pathway. The cell cycle and proliferation of HepG2 cells treated with FZD were detected by flow cytometry and MTT assay in the presence or absence of p38 MAPK inhibitors (SB203580), respectively. Cyclin D1, cyclin D3 and CDK6 were detected by quantitative real-time PCR and western blot analysis. Our data showed that p38 MAPK became phosphorylated after stimulation with FZD. Activation of p38 MAPK could arise S-phase cell-cycle arrest and suppress cell proliferation. Simultaneously, inhibition of the p38 MAPK signaling pathway significantly prevented S-phase cell-cycle arrest, increased the percentage of cell viability and decreased the expression of cyclin D1, cyclin D3 and CDK6. These results demonstrated that FZD arose S-phase cell-cycle arrest via activating the p38 MAPK signaling pathway in HepG2 cells. Cyclin D1, cyclin D3 and CDK6 are target genes functioning at the downstream of p38 MAPK in HepG2 cells induced by FZD.

Furazolidone-based therapies for Helicobacter pylori infection: a pooled-data analysis

BACKGROUND/AIM

Furazolidone-based therapies are used in developing countries to cure Helicobacter pylori infection due to its low cost. The low bacterial resistance toward furazolidone may render appealing the use of this drug even in developed countries. However, some relevant safety concerns do exist in using furazolidone.

PATIENTS AND METHODS

This was a systematic review with pooled-data analysis of data regarding both eradication rate and safety of furazolidone-based therapies for H. pylori infection. Intention-to-treat (ITT) and per-protocol (PP) eradication rates were calculated.

RESULTS

Following furazolidone-based first-line therapy, H. pylori eradication rates were 75.7% and 79.6% at ITT and PP analysis, respectively (P<0.001). The overall incidence of side effects and severe side effects were 33.2% and 3.8%, respectively. At multivariate analysis, only high-dose furazolidone was associated with increased therapeutic success (OR: 1.5, 95% CI: 1.3-2.7; P<0.001), while occurrence of side effects was relevant following treatment for a long duration (OR: 2.9, 95% CI: 2.2-4.1; P<0.001), high-dose furazolidone (OR: 2.3, 95% CI: 1.7-3.2; P<0.001) and bismuth-containing regimens (OR: 2.1, 95% CI: 1.5-2.8; P<0.001).

CONCLUSIONS

Furazolidone-based regimens usually achieve low eradication rates. Only a high-dose regimen improves the cure rate, but simultaneously increases the incidence of severe side effects. Therefore, we suggest that patients have to be clearly informed about the possible genotoxic and carcinogenetic effects for which furazolidone use is not approved in developed countries.

Identification and functional analysis of a miR-622 eukaryotic expression vector targeting the ING1 gene in human gastric cancer cell line MKN-45

AIM: To investigate the function of miR-622 in human gastric cancer cell line MKN-45 by constructing a miR-622 eukaryotic expression vector targeting the ING1 gene and to explore the potential role of miR-622 in gastric carcinogenesis.

METHODS: A recombinant plasmid carrying miR-622 (pSuper/miR-622) was transfected into MKN-45 cells using lipofectin-mediated method. Cells stably expressing miR-622 were selected using G418. MKN-45 cells untransfected and those transfected with empty pSuper plasmid were used as controls. The expression levels of miR-622 were detected by TaqMan real-time PCR in stably transfected MKN-45 cells, and Western blot was used to detect the expression of ING1 protein.

RESULTS: Compared to untransfected MKN-45 cells, the expression of ING1 protein showed an average 4.63-fold decrease (1.83 ± 0.86 vs 8.47 ± 1.43, P < 0.05). MKN-45 cells tranfected with pSuper/miR-622 showed higher cell growth activity than control cells (P < 0.05). Over-expression of miR-622 in MKN-45 cells promoted cell cycle progression (G₀/G₁ phase: 21.45 ± 0.16 vs 48.21 ± 0.34; G₂ / M phase: 53.67 ± 0.41 vs 20.27 ±0.18) compared to cells transfected with pSuper empty vector.

CONCLUSION: A MiR-622 eukaryotic expression vector that can stably express miR-622 in MKN-45 cells has been successfully constructed and can be used to study the functions of miR-622 in human gastric cancer.