Circ_MACF1 targets miR-421 to upregulate FMO2 to suppress paclitaxel resistance and malignant cellular behaviors in lung adenocarcinoma.

BACKGROUND: Chemoresistance remains an enormous challenge in the treatment of lung adenocarcinoma (LADC). Circular RNAs (circRNAs) exhibit important regulation in tumor progression and chemoresistance. This research focused on exploring the regulatory function and mechanism of circ_MACF1 (has_circ_0011780) in paclitaxel (PTX) resistance in LADC. METHODS: Circ_MACF1, miR-421 and flavin-containing monooxygenase 2 (FMO2) were determined by RT-qPCR. MTT was applied to detect IC50 of PTX. The proliferation analysis was performed using EdU and colony formation assay. Cell apoptosis and motility were examined using flow cytometry and transwell assay, respectively. Western blot was administered for protein detection. A dual-luciferase reporter assay was performed for confirming target interaction. PTX sensitivity in vivo was researched via xenograft tumor assay. RESULTS: Expression of circ_MACF1 was decreased in PTX-resistant LADC tissues and cells. Circ_MACF1 overexpression reduced chemoresistance, proliferation, motility and accelerated apoptosis in PTX-resistant LADC cells. Circ_MACF1 targeted miR-421 and miR-421 upregulation reverted circ_MACF1-evoked effects. FMO2 served as a downstream target of miR-421 and circ_MACF1 sponged miR-421 to elevate the expression of FMO2. MiR-421 enhanced PTX resistance and LADC progression via targeting FMO2. FMO2 knockdown enhanced IC50 of PTX and cell proliferation. In vivo, circ_MACF1 elevated PTX sensitivity of LADC by mediating miR-421/FMO2 axis. CONCLUSION: These findings elucidated that circ_MACF1 inhibited PTX resistance by absorbing miR-421 to upregulate FMO2 in LADC.

Unlocking the potential of iridium and ruthenium arene complexes as anti-tumor and anti-metastasis chemotherapeutic agents.

It is a major challenge to design novel multifunctional metal-based chemotherapeutic agents for anti-tumor and anti-metastasis applications. Two complexes (OA-Ir and OA-Ru) were synthesized via CuAAC (copper-catalyzed azide-alkyne cycloaddition) reaction from nontoxic Ir-N3 or Ru-N3 species and low toxic alkynyl precursor OA-Alkyne, and exhibited satisfactory anti-tumor and anti-metastasis pharmacological effects. Conjugation of Oleanolic acid (OA) and metal-arene species significantly enhanced the cytotoxicity in A2780 cells compared to the precursors through mitochondrial-induced autophagy pathway. Moreover, the two complexes could inhibit the cell metastasis and invasion through damage of actin dynamics and down-regulation of MMP2/MMP9 proteins. Combination of two precursors improved the lipophilicity and biocompatibility, simultaneously enhanced the cell uptake and the mitochondrial accumulation of metal-arene complexes, which caused mitochondrial membrane potential damage, oxidative phosphorylation, ATP depletion and autophagy. Besides, OA-Ir and OA-Ru displayed excellent activity to disintegrate the 3D multicellular tumor spheroids, showing potential for the treatment of solid tumors. This work provides a new way for developing novel metal-based complexes via CuAAC reaction for simultaneously inhibiting tumor proliferation and metastasis.

Effect of polar/non-polar facets on the transformation of nanoscale ZnO in simulated sweat and potential impacts on the antibacterial activity.

The use of nanoscale zinc oxide (n-ZnO) in the personal care products would cause interactions between n-ZnO and human sweat. Facet engineering has been applied to n-ZnO to improve its activity. Nevertheless, it is not clear whether the exposed facet would affect transformation of n-ZnO in sweat. Herein, we prepared ZnO nanoneedles with the dominant (1010) non-polar facet (i.e., ZnO-1010) and ZnO nanoflakes with the dominant (0001) polar facet (i.e., ZnO-0001), respectively. We found that n-ZnO can undergo chemical transformation in the simulated sweat within 168 h or 24 h, transforming into amorphous materials and Zn3(PO4)20.4 H2O and/or Na(ZnPO4)·H2O. Given the rate constant (e.g., 0.093 h-1 for ZnO-0001 vs. 0.033 h-1 for ZnO-1010) of ZnO depletion and components of the precipitate from the simulated sweat, nevertheless, the transformation is highly dependent on the dominant exposed facet of n-ZnO. The ZnO-0001 relative to ZnO-1010 would likely undergo chemical transformation, demonstrating that the (0001) polar facet compared to (1010) non-polar facet had a superior activity to the dihydrogen phosphate anions in the simulated sweat, which is supported by density functional theory calculations. The chemical transformation can affect the antibacterial activity of n-ZnO to E. coli, moderating the toxicity due to a great decrease in the concentration of the dissolved zinc. In total, our findings provided insights into the facet-dependent transformation for n-ZnO in the simulated sweat, improving our understanding of potential risk of n-ZnO.

A New Strategy to Fight Metallodrug Resistance: Mitochondria-Relevant Treatment through Mitophagy to Inhibit Metabolic Adaptations of Cancer Cells.

Metabolic adaptations can help cancer cells to escape from chemotherapeutics, mainly involving autophagy and ATP production. Herein, we report a new rhein-based cyclometalated IrIII complex, Ir-Rhein, that can accurately target mitochondria and effectively inhibit metabolic adaptations. The complex Ir-Rhein induces severe mitochondrial damage and initiates mitophagy to reduce the number of mitochondria and subsequently inhibit both mitochondrial and glycolytic bioenergetics, which eventually leads to ATP starvation death. Moreover, Ir-Rhein can overcome cisplatin resistance. Co-incubation experiment, 3D tumor spheroids experiment and transcriptome analysis reveal that Ir-Rhein shows promising antiproliferation performance for cisplatin-resistant cancer cells with the regulation of platinum resistance-related transporters. To our knowledge, this is a new strategy to overcome metallodrug resistance with a mitochondria-relevant treatment.

Hydrogen sulfide triggered molecular agent for imaging and cancer therapy.

We developed an activatable molecular reagent, PNF, triggered by intracellular H2S in the lysosome to release the therapeutic drug amonafide, which can escape from the lysosome into the nucleus to induce autophagy of cancer cells. PNF exhibits potent inhibitory activity against cisplatin-resistant tumor cell lines.

Chemical transformations of nanoscale zinc oxide in simulated sweat and its impact on the antibacterial efficacy.

Nanoscale zinc oxide (n-ZnO) is widely used in personal care products and textiles, thus, it would likely be released into human sweat. To better evaluate the potential human health risks of n-ZnO, it is essential to understand its chemical transformations in physiological solutions, such as human sweat, and the resulting changes in the n-ZnO bioavailability. Here, two types of n-ZnO, ZnO nanoparticles (ZnO-NPs) and nanorod-based ZnO nanospheres (ZnO-NSs) were synthesized and incubated in 3 types of simulated sweat with different pH values and phosphate concentrations. The content of Zn3(PO4)2 in the transformed n-ZnO was quantified by selective dissolution of Zn3(PO4)2 in 0.35 M ammonia solution where 100% and 5.5% of Zn3(PO4)2 and ZnO were dissolved, respectively. The kinetics analysis indicated that by 24-48 h the content of Zn3(PO4)2 reached the maximum, being 15-21% at pH 8.0 and 45-70% at pH 5.5 or 4.3. Interestingly, no correlation was observed between the rate constants of Zn3(PO4)2 formation and the specific surface areas of n-ZnO, implying that chemical transformations from n-ZnO to Zn3(PO4)2 in the simulated sweat might not be simply attributed to dissolution and precipitation. Using a variety of characterization techniques, we demonstrated the formation of a ZnO‒Zn3(PO4)2 core-shell structure with the shell consisting of amorphous Zn3(PO4)2 at pH 8.0 and additionally of crystalline Zn3(PO4)2 and Zn3(PO4)2•4H2O at pH 5.5 or 4.3. The phosphate-induced transformation of n-ZnO in the simulated sweat at pH 5.5 and 4.3 greatly reduced the antibacterial efficacy of n-ZnO through moderating the nanoparticle dissolution, indicating limited bioavailability of the NPs upon transformation. The results improve the understanding of the fate and hazards of n-ZnO.

Transformations of Ag2S nanoparticles in simulated human gastrointestinal tract: Impacts of the degree and origin of sulfidation.

Engineered silver sulfide nanoparticles (e-Ag2S-NPs) are used in industry and can be released into the environment. Besides e-Ag2S-NPs, transformed silver sulfide nanoparticles (t-Ag2S-NPs) from silver nanoparticles are more likely to be the form that is widely distributed in the environment. Both e-Ag2S-NPs and t-Ag2S-NPs may be ingested and get into human gastrointestinal tract (GIT) through trophic transfer, posing a potential threat to human health. Nevertheless, knowledge of chemical stability of t-Ag2S-NPs and e-Ag2S-NPs in the human GIT is very limited. Herein e-Ag2S-NPs and a series of t-Ag2S-NPs with different degrees of sulfidation were selected as models for exposure to the simulated human GIT including mouth, stomach and small intestine phases under fed and fasted conditions. Silver ions were detected in the simulated saliva, gastric and small intestine fluids when t-Ag2S-NPs or e-Ag2S-NPs were incubated in the simulated GIT, but the amount (e.g., < 20 µg) of silver ion in each phase accounted for < 0.2‰ (w/w) of the silver added (i.e., 100 mg). Silver species of the residual particulate from each phase of the simulated GIT with t-Ag2S-NPs or e-Ag2S-NPs were thus analyzed through a developed analytical method that could selectively, successively and efficiently dissolve and quantify AgCl, Ag(0), and Ag2S in particulates. Both e-Ag2S-NPs and fully sulfidized t-Ag2S-NPs were shown to be highly stable in the simulated human GIT. Conversely, partially sulfidized t-Ag2S-NPs primarily underwent transformations in the mouth phase relative to stomach and small intestine phases regardless of fed or fasted status, wherein AgCl and Ag2S were observed besides Ag(0). The amount of Ag2S in the mouth phase negatively (r = -0.99, p < 0.001) correlated with the sulfidation degree of initial t-Ag2S-NPs. This work improved our understanding of potential transformations of t-Ag2S-NPs in the simulated human GIT, providing valuable information for future researches on evaluating health risks of ingested Ag2S-NPs.

Environmentally relevant concentrations of microplastic exhibits negligible impacts on thiacloprid dissipation and enzyme activity in soil.

Microplastics (MPs) as a type of emerging contaminant in the environment have attracted extensive attentions in recent years, and understanding the impacts of MPs on soil biodiversity and functioning are thus increasingly urgent. Nevertheless, few studies were performed to investigate potential effects of MPs on decay of soil organic pollutants in particular pesticides and enzyme activities. Herein, three types of MPs including polystyrene fragments (PS-50) and polyvinyl chloride beads (PVC-42000 and PVC-10) were added to soil at environmentally relevant concentrations (0.2 and 1.0%) to study their impacts on dissipation of thiacloprid and activities of urease, acid phosphatase, invertase and catalase. MPs exhibited negligible impacts on thiacloprid dissipation regardless of MPs type and content, being probably attributed to the unaltered bioavailability of thiacloprid in soil even after an addition of MPs, which was documented by using the hydroxypropyl-ß- cyclodextrin (HPCD) extraction method. Batch sorption experiments also exhibited the comparable adsorption capacity of thiacloprid to soil with and without MPs, along with Kf valuses of 3.44-3.77. Besides, MPs exerted negligible effects on enzyme activities of soil. Taken together, this study showed negligible impacts of MPs at environmentally relevant concentrations on thiacloprid dissipation and enzyme activity, expanding our knowledge on impacts of MPs at the environmentally relevant concentrations on pesticide dissipation in soil.

Sulfidation of sea urchin-like zinc oxide nanospheres: Kinetics, mechanisms, and impacts on growth of Escherichia coli.

Nanoscale zinc oxide (n-ZnO) with different morphology and sizes has been used in personal care products due to their antibacterial properties, resulting in discharge of n-ZnO into the environment with potential toxic effect to ecological systems. Sulfidation is one of pathways of transformation of n-ZnO, but a very limited information on the conversion of n-ZnO under sulfidic environment with special morphology such as sea urchin-like zinc oxide nanospheres (ZnO-NSs) is available to know the potential environmental risks of n-ZnO. Herein, sea urchin-like ZnO-NSs with an average size of 78 nm were synthesized and adopted as the model n-ZnO of special morphology. The ZnO-NPs at average sizes of 71 nm (ZnO-NPs-71), 48 nm (ZnO-NPs-48), and 17 nm (ZnO-NPs-17) nm were used to examine possible differences in the sulfidation between the sea urchin-like ZnO-NSs and ZnO-NPs. A new analytical method selectively dissolving ZnO over ZnS in partially sulfidized n-ZnO was developed and applied to understand the kinetics of n-ZnO sulfidation. The sulfidation rate constant (ks) of sea urchin-like ZnO-NSs was 2.9 × 10-3 h-1, comparable to that of ZnO-NPs-71 (4.1 × 10-3 h-1), but much lower than those of ZnO-NPs-48 (20.1 × 10-3 h-1) and ZnO-NPs-17 (67.8 × 10-3 h-1). This might be attributed to the differences in the specific surface area; ks positively correlated with the specific surface area (R2 = 0.97). Natural organic matter (NOM) decreased dissolution and sulfidation of the sea urchin-like ZnO-NSs. Aggregate ZnS nanocrystals instead of the original sea urchin-like ZnO-NSs were observed. We proposed that sea urchin-like ZnO-NSs were transformed to ZnS through a dissolution-precipitation pathway, consistent with the sulfidation pathway of ZnO-NPs. Sulfidation drastically reduced toxicity of sea urchin-like ZnO-NSs to Escherichia coli due to negligible dissolution of ZnS nanocrystals. These results greatly improved our understanding of the transformation and potential risks of n-ZnO with special morphology.

Assessing the Impacts of Cu(OH)2 Nanopesticide and Ionic Copper on the Soil Enzyme Activity and Bacterial Community.

Nanopesticides are being introduced in agriculture, and the associated environmental risks and benefits must be carefully assessed before their widespread agricultural applications. We investigated the impacts of a commercial Cu(OH)2 nanopesticide formulation (NPF) at different agricultural application doses (e.g., 0.5, 5, and 50 mg of Cu kg-1) on enzyme activities and bacterial communities of loamy soil (organic matter content of 3.61%) over 21 days. Results were compared to its ionic analogue (i.e., CuSO4) and nano-Cu(OH)2, including both the commercial unformulated active ingredient of NPF (AI-NPF) and synthesized Cu(OH)2 nanorods (NR). There were negligible changes in the activity of acid phosphatase, regardless of exposure dose, whereas significant (p < 0.05) variations in activities of invertase, urease, and catalase were observed at a dose of 5 mg kg-1 or higher. Invertase activity decreased with an increasing bioavailable Cu concentration in soil under various treatments. In comparison to CuSO4, both Cu(OH)2 nanopesticide (i.e., NPF) and nano-Cu(OH)2 (i.e., AI-NPF and NR) caused a significant (p < 0.05) inhibition of urease activity, wherein a significant (p < 0.05) increase in the activity of catalase was observed, representing serious oxidative stress. Accordingly, NPF, AI-NPF, and NR differently affected soil bacterial abundance, diversity, and community compared to CuSO4, which could have resulted from the changes in the bioavailable Cu concentration as a result of the distinct nature of copper spiked (i.e., nano form versus salt). Moreover, minor differences in the soil enzyme activity and bacterial community were observed between NPF and AI-NPF, reflecting that the impact of the Cu(OH)2 nanopesticide was primarily attributed to the presence of nano-Cu(OH)2. In total, the impacts of nano-Cu(OH)2 on the soil bacterial community and enzyme activity tested in this study differed from CuSO4, shedding light on the environmental risks of the Cu(OH)2 nanopesticide in the long run.

Potential environmental risks of nanopesticides: Application of Cu(OH)2 nanopesticides to soil mitigates the degradation of neonicotinoid thiacloprid.

Cu(OH)2 nanopesticides and organic insecticides are continuously applied to soil at a temporal interval, while knowledge about the impact of Cu(OH)2 nanopesticides on organic insecticides degradation is currently scarce, resulting in poorly comprehensive evaluation of the potential environmental risks of Cu(OH)2 nanopesticides. Herein, a commercial Cu(OH)2 nanopesticide formulation (NPF), the active ingredient of NPF (AI-NPF), the prepared Cu(OH)2 nanotubes (NT) with comparable morphology and size to AI-NPF, and CuSO4 were respectively applied to soil at normal doses (0.5, 5 and 50 mg/kg), followed by an application of neonicotinoid thiacloprid after an interval of 21 d, showing that NPF at doses of 5 and 50 mg/kg significantly (p < 0.05) mitigated thiacloprid degradation compared to control and CuSO4. Furthermore, AI-NPF was the primary component that contributed to the mitigation effect of NPF, which was also validated by the NT. Large differences in the degradation efficiency of thiacloprid in sterilized and unsterilized soils with Cu(OH)2 nanopesticides suggested that biodegradation was the primary process responsible for thiacloprid degradation, especially as chemical degradation was negligible. Besides a decrease of thiacloprid bioavailability due to adsorption by Cu(OH)2 nanopesticides, we demonstrated that Cu(OH)2 nanopesticides changed soil microbial communities, reduced nitrile hydratase activity and down-regulated thiacloprid-degradative nth gene abundance, which thus mitigated thiacloprid biodegradation. Clearly, this study shed light on the potential environmental risks of Cu(OH)2 nanopesticide.

Effect of oligonucleotide probes substituted by deoxyinosines on the specificity of SNP detection on the DNA microarray.

One of the main factors that can affect the quality of microarray results is the microarray hybridization specificity. The key factor that affects hybridization specificity is the design of the probes. In this paper, we described a novel oligonucleotide probe containing deoxyinosines aimed at improving DNA hybridization specificity. We compared different probes to determine the distance between deoxyinosine base and SNPs site and the number of deoxyinosine bases. The new probe sequences contained two set of deoxyinosines (each set had two deoxyinosines), in which the interval between SNP site and each set of deoxyinosines was two bases. The new probes could obtain the highest hybridization specificity. The experimental results showed that probes containing deoxyinosines hybridized effectively to the perfectly matched target and improved the hybridization specificity of DNA microarray. By including a simple washing step after hybridization, these probes could distinguish matched targets from single-base-mismatched sequences perfectly. For the probes containing deoxyinosines, the fluorescence intensity of a match sequence was more than eight times stronger than that of a mismatch. However, the intensity ratio was only 1.3 times or less for the probes without deoxyinosines. Finally, using hybridization of the PCR product microarrays, we successfully genotyped SNP of 140 samples using these new labeled probes. Our results show that this is a useful new strategy for modifying oligonucleotide probes for use in DNA microarray analysis.

Probe optimization for sequencing by ligation.

Sequencing by ligation (SBL) is a straightforward enzymatic method for interrogating DNA sequence, in which the ligation efficiency and specificity of each probe play an essential role. Here, the number of labelled dyes in the probe, probe length and probe constituent were investigated to optimize the ligation efficiency and specificity. First, the performance of double- and single-labelled fluorescent probes in SBL was evaluated. The experimental results showed that double-labelled fluorescent probes could yield a remarkable increase in the fluorescence intensities and avoid higher background compared with single-labelled fluorescent probes. Second, probes between 7- and 9-mers in length were designed to uniform Tm difference. We hoped the uniformed probes with smaller Tm difference could improve the ligation efficiency. However, 8-mer probes with larger Tm difference showed stronger fluorescence intensities. Third, we evaluated whether probes containing deoxyinosines either in the 5' or the 3' end had influence on the ligation efficiency. Consequently, probes containing deoxyinosines at the 5' termini might decrease the ligation efficiency, and the accumulation of 3' terminal deoxyinosines in the sequencing primers was likely to reduce the fluorescence intensity and the ligation efficiency, which was inconsistent with the traditional viewpoint. The optimized probes will improve the ligation efficiency and accuracy in SBL.