Amino acid metabolism and MAP kinase signaling pathway play opposite roles in the regulation of ethanol production during fermentation of sugarcane molasses in budding yeast.

Sugarcane molasses is one of the main raw materials for bioethanol production, and Saccharomyces cerevisiae is the major biofuel-producing organism. In this study, a batch fermentation model has been used to examine ethanol titers of deletion mutants for all yeast nonessential genes in this yeast genome. A total of 42 genes are identified to be involved in ethanol production during fermentation of sugarcane molasses. Deletion mutants of seventeen genes show increased ethanol titers, while deletion mutants for twenty-five genes exhibit reduced ethanol titers. Two MAP kinases Hog1 and Kss1 controlling the high osmolarity and glycerol (HOG) signaling and the filamentous growth, respectively, are negatively involved in the regulation of ethanol production. In addition, twelve genes involved in amino acid metabolism are crucial for ethanol production during fermentation. Our findings provide novel targets and strategies for genetically engineering industrial yeast strains to improve ethanol titer during fermentation of sugarcane molasses.

Identification of the Beta Subunit Fas1p of Fatty Acid Synthetase as an Interacting Partner of Yeast Calcium/Calmodulin-Dependent Protein Kinase Cmk2p Through Mass Spectrometry Analysis.

The calcium/calmodulin-dependent protein kinase II (CaMKII) is a mediator of calcium signals and regulates fatty acid metabolism in mammalian cells. Cmk2p is a yeast homolog of CaMKII and functions as a negative regulator of calcium signaling. However, its substrates remain to be identified. Combination of immunoprecipitation (IP) and mass spectrometry has been proven to be very useful for identification of interacting partner proteins and interactome. In this study, through these approaches, we have identified 65 and 110 potential Cmk2p-interacting proteins in yeast cells in the absence or presence of calcium stress, respectively. In yeast cells expressing both CMK2-HA and FAS1-GFP fusion proteins, in the absence or presence of calcium stress, less amounts of FAS1-GFP proteins are present in cell lysates after IP with anti-HA antibody than cell lysates before IP, while FAS1-GFP proteins are detected on both types of IP beads. However, as an internal control, similar amounts of Pgk1p proteins were detected in both after-IP and before-IP cell lysates but not on the IP beads. Therefore, our biochemical analysis demonstrates that the ß subunit Fas1p of fatty acid synthetase interacts with Cmk2p in yeast cells independent of calcium stress. It is also interesting to note that, in addition to the expected 52-kDa CMK2-HA band, a faster-moving 48-kDa CMK2-HA band is present in the calcium-stressed cell lysate but not in the cell lysate without calcium stress. Our data would provide important clues for understanding the functions of CaMKII in the regulation of fatty acid metabolism as well as related diseases such as cancers, diabetes, and obesity.

SIRT7 promotes Hippo/YAP activation and cancer cell proliferation in hepatocellular carcinoma via suppressing MST1.

Abnormal activation of the oncogene YAP in the Hippo pathway is a major feature in liver cancer and inactivation of MST1/2 has been shown to be responsible for the overactivation of YAP that led to tumorigenesis. However, mechanisms underlying MST1/2 dysregulation remain poorly understood. RNA-seq analysis and genome (KEGG) pathway enrichment analysis were used to identify genes and pathways that were regulated by SIRT7. qRT-PCR, ChIP, and luciferase assay were used to investigate transcriptional regulation. Mass spectrometry, co-immunoprecipitation and immunoprecipitation were used to exam protein-protein interaction and post-transcriptional modification. A xenograft mouse model was used to confirm the effect of SIRT7 and SIRT7 inhibitors on hepatocellular carcinoma (HCC) proliferation in vivo. We found that SIRT7 suppresses MST1 by both transcriptional regulation and post-transcriptional modification, which in turn promotes YAP nuclear localization and transcriptional activation in liver cancer. Mechanistically, we revealed that SIRT7 suppresses MST1 transcription by binding to the MST1 promoter and inducing H3K18 deacetylation in its promoter region. In addition, SIRT7 directly binds to and deacetylates MST1, which primes acetylation-dependent MST1 ubiquitination and protein degradation. In clinical samples, we confirmed a negative correlation between SIRT7 and MST1 protein levels, and high SIRT7 expression correlated with elevated YAP expression and nuclear localization. In addition, SIRT7 specific inhibitor 2800Z sufficiently inhibited HCC growth by disrupting the SIRT7/MST1/YAP axis. Our data thus revealed the previously undescribed function of SIRT7 in regulating the Hippo pathway in HCC and further proved that targeting SIRT7 might provide novel therapeutic options for the treatment of liver cancer.

Transcriptional expression of PHR2 is positively controlled by the calcium signaling transcription factor Crz1 through its binding motif in the promoter.

IMPORTANCE: The fungal cell wall consists of glucans, mannoproteins, and chitin and is essential for cell viability, morphogenesis, and pathogenesis. The enzymes of the GH72 family are responsible for ß-(1,3)-glucan elongation and branching, which is crucial for the formation of the glucan-chitin polymer at the bud neck of yeast cells. In the human fungal pathogen Candida albicans, there are five GH72 enzyme-encoding genes: PHR1, PHR2, PHR3, PGA4, and PGA5. It is known that expression of PHR1 and PHR2 is controlled by the pH-responsive Rim101 pathway through the transcription factor Rim101. In this study, we have demonstrated that the transcription expression of PHR2 is also controlled by the transcription factor Crz1 through its binding motif in the promoter. Therefore, we have uncovered a dual-control mechanism by which PHR2 expression is negatively regulated via CaRim101 through the pH-responsive pathway and positively modulated by CaCrz1 through the calcium/calcineurin signaling pathway.

On prediction of chaotic dynamics in semiconductor lasers by reservoir computing.

Studying the chaotic dynamics of semiconductor lasers is of great importance for their applications in random bit generation and secure communication. While considerable effort has been expended towards investigating these chaotic behaviors through numerical simulations and experiments, the accurate prediction of chaotic dynamics from limited observational data remains a challenge. Recent advancements in machine learning, particularly in reservoir computing, have shown promise in capturing and predicting the complex dynamics of semiconductor lasers. However, existing works on laser chaos predictions often suffer from the need for manual parameter optimization. Moreover, the generalizability of the approach remains to be investigated, i.e., concerning the influences of practical laser inherent noise and measurement noise. To address these challenges, we employ an automated optimization approach, i.e., a genetic algorithm, to select optimal reservoir parameters. This allows efficient training of the reservoir network, enabling the prediction of continuous intensity time series and reconstruction of laser dynamics. Furthermore, the impact of inherent laser noise and measurement noise on the prediction of chaotic dynamics is systematically examined through numerical analysis. Simulation results demonstrate the effectiveness and generalizability of the proposed approach in achieving accurate predictions of chaotic dynamics in semiconductor lasers.

Occurrence of microplastics and disturbance of gut microbiota: a pilot study of preschool children in Xiamen, China.

BACKGROUND: Microplastics (MPs) have garnered widespread attention because of their presence in human placenta, stool, and even blood. Ingestion is considered the major route of human exposure to MPs. It has been found that the consumption of food and water is associated with more MP abundance in human stools. The usage of plastic containers, particularly feeding bottles, may be a major contributor to MP contamination. However, human exposure to MPs and potential factors that influence exposure, especially for preschoolers, remains largely unknown. When exposed to MPs, mice exhibited gut microbiota dysbiosis, including alterations in diversity indices, a decreased relative abundance of probiotics and an increased abundance of pathogenic bacteria. Such results have also been observed in human gut in vitro models, however, the actual association between MP exposure and human intestinal microbiota remains unclear. Therefore, this study aimed to evaluate MP concentrations in preschoolers' stools, explore possible dietary factors that influence preschooler exposure to MPs, and investigate their potential association with the gut microbiota. METHODS: A cross-sectional study was conducted in Xiamen, China in October 2022. We investigated the feeding behaviours and dietary habits of preschool children. A total of 69 couples of stool samples were collected and analyzed for MPs test and gut microbiota analysis. Pyrolysis-gas chromatography coupled with mass spectrometry (Py-GC/MS) was used for quantifying 11 types of MPs. The gut microbiota composition was analyzed by 16S rRNA gene sequencing. FINDINGS: The results showed that only polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyethylene (PE), and polyamide 6 (PA6) were detected in 85.5% stool samples, with concentrations of 317.4 (152.0, 491.9) µg/g dw, 299.0 (196.1, 619.9) µg/g dw, 206.2 (154.1, 240.3) µg/g dw, and 17.9 (13.4, 18.6) µg/g dw, respectively. The median estimated daily intake (EDI) for preschoolers was 425.9 (272.5, 762.3) µg/kg-bw/d. Dairy intake may influence MP concentration in preschoolers' stools, and the usage of feeding bottles may be a specific source of MP contamination. Moreover, higher PVC concentrations were observed in the stools when the children took more time to eat a meal. MP exposure was inversely associated with alpha indices and possibly affected certain probiotic taxa, such as Parabacteroides and Alistipes, in preschool children. INTERPRETATION: Our data provided baseline evidence for MP exposure doses and potential dietary factors that may influence MP exposure in preschoolers. These findings supported the perspective that MP exposure might be associated with the disturbance of gut microbiota. Further studies focusing on sensitive populations with larger sample sizes are needed. FUNDING: This study was funded by the National Natural Science Foundation of China (grant number: 82003412), the Shanghai Municipal Health Commission (grant number: 20214Y0019), and the Project of Shanghai Municipal Financial Professional foundation (Food Safety Risk Assessment) (grant number: RA-2022-06).

High-performance grating couplers on 220-nm thick silicon by inverse design for perfectly vertical coupling.

Efficient grating couplers (GCs) for perfectly vertical coupling are difficult to realize due to the second-order back reflection. In this study, apodized GCs (AGCs) are presented for achieving perfectly-vertical coupling to 220 nm thick silicon-on-insulator (SOI) waveguides in the C-band. We compare the performance of the AGCs to that of uniform GCs (UGCs) and demonstrate the superiority of the former. The AGCs were obtained through inverse design using gradient-based optimization and were found to effectively suppress back reflection and exhibit better matching to the Gaussian beam profile. The design and measurement results show that AGCs have a 3 dB lower coupling loss than UGCs. We fabricated focusing AGCs by electron beam lithography with a single, 70 nm shallow etch and a minimum feature size of 100 nm, which makes them compatible with CMOS technology. The AGCs achieved a coupling efficiency of -5.86 dB for perfectly vertical coupling. Overall, our results demonstrate the potential of AGCs for achieving high-performance coupling in the C-band on the SOI platform.

The Therapeutic Effect of Catechin on Nephrolithiasis Induced by Co-Exposure to Melamine and Cyanuric Acid in Sprague-Dawley Rats.

This study aimed to assess the therapeutic efficacy of catechin against experimentally induced kidney stones resulting from co-exposure to melamine (MEL) and cyanuric acid (CYA) in male Sprague-Dawley rats. To induce nephrolithiasis, a combination of MEL and CYA (1:1 ratio, each at a dose of 31.5 mg/kg bw/day) was administered to the rats for 28 consecutive days. After nephrolithiasis was successfully induced, the rats were randomly divided into two groups: a treatment group and a sham group. The treatment group was given a daily oral dose of 50 mg/kg of catechin for 28 days, while the sham group received no intervention. Urine and blood samples were collected throughout the treatment period, and kidney samples were taken on day 28. Our findings demonstrated that treatment with catechin significantly reduced crystal deposition and pathological damage in the rats from nephrolithiasis. Additionally, renal injury markers were significantly decreased in the treatment group compared to the sham group. These findings suggest that catechin has potential therapeutic benefits in treating nephrolithiasis induced by co-exposure to MEL and CYA.

A glycosylated Phr1 protein is induced by calcium stress and its expression is positively controlled by the calcium/calcineurin signaling transcription factor Crz1 in Candida albicans.

As one of the most important human fungal pathogens, Candida albicans senses and adapts to host niches with different pH values through the pH-responsive Rim101 pathway. Its transcription factor Rim101 activates the expression of alkaline pH-induced genes including PHR1 that encodes a glycosylphosphatidylinsitol-anchored ß(1,3)-glucanosyltransferase critical for hyphal wall formation. The calcium/calcineurin signaling pathway is mediated by the transcription factor Crz1 in yeasts and other lower eukaryotes. Here we report that deletion of PHR1 leads to calcium sensitivity of C. albicans cells. In addition, expression of Phr1 is induced by calcium stress and under the control of Crz1 in C. albicans. EMSA assay demonstrates that Crz1 binds to one CDRE element in the PHR1 promoter. Alkaline treatment induces two species of glycosylated Phr1 proteins with different degrees of glycosylation, which is independent of Crz1. In contrast, only one species of Phr1 protein with a low degree of glycosylation is induced by calcium stress in a Crz1-dependent fashion. Therefore, we have provided an evidence that regulation of cell wall remodeling is integrated through differential degrees of Phr1 glycosylation by both the pH-regulated Rim101 pathway and the calcium/calcineurin signaling pathway in C. albicans. Video Abstract.

Rogue wave generation using a chaotic semiconductor laser with energy redistribution.

We demonstrate for the first time that optical rogue waves (RWs) can be generated using a chaotic semiconductor laser with energy redistribution. Chaotic dynamics are numerically generated using the rate equation model of an optically injected laser. The chaotic emission is then sent to an energy redistribution module (ERM) that consists of a temporal phase modulation and a dispersive propagation. The process enables a temporal energy redistribution of the chaotic emission waveforms, where coherent summation of consecutive laser pulses leads to random generation of giant intensity pulses. Efficient generation of optical RWs are numerically demonstrated by varying the ERM operating parameters in the entire injection parameter space. The effects of the laser spontaneous emission noise on the generation of RWs are further investigated. The RW generation approach offers a relatively high flexibility and tolerance in the choice of ERM parameters according to the simulation results.

Design, synthesis and biological evaluation of liposome entrapped iridium(III) complexes toward SGC-7901 cells.

In this study, two new iridium(III) polypyridyl complexes [Ir(bzq)2(DIPH)](PF6) (bzq = deprotonated benzo[h]quinoline, DIPH = 4-(2,5-dibromo-4-(1H-imidazo[4,5-f][1,10]phenanthrolim-2-yl)-4-hydroxybutan-2-one) (Ir1) and [Ir(piq)2(DIPH)](PF6) (piq = deprotonated 1-phenylisoquinoline) (Ir2) were synthesized and characterized by elemental analysis, HRMS, 1H and 13C NMR. The cytotoxic activity of Ir1, Ir2, Ir1lipo and Ir2lipo against cancer cells SGC-7901, HepG2, A549, HeLa, B16 and normal NIH3T3 cells in vitro was evaluated using 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide (MTT) method. Ir1 and Ir2 showed no cytotoxic activity, but their liposome-entrapped Ir1 (Ir1lipo) and Ir2 (Ir2lipo) showed significant cellular activity, especially sensitive to SGC-7901 with IC50 values of 4.7 ± 0.2 and 12.4 ± 0.5 µM, respectively. The cellular uptake, endoplasmic reticulum (ER) localization, autophagy, tubulin polymerization, glutathione (GSH), malondialdehyde (MDA) and release of cytochrome c were investigated to explore the mechanisms of apoptosis. The calreticulin (CRT), heat shock protein 70 (HSP70), high mobility group box 1 (HMGB1) were also explored. Western blotting showed that Ir1lipo and Ir2lipo inhibited PI3K (phosphoinositide-3 kinase), AKT (protein kinase B), p-AKT and activated Bcl-2 (B-cell lymphoma-2) protein and apoptosis-regulated factor caspase 3 (cysteinyl aspartate specific proteinase-3) and cleaving PARP (poly ADP-ribose polymerase). The results demonstrated that Ir1lipo and Ir2lipo induce cell apoptosis through targeting the endoplasmic reticulum (ER), cause oxidative stress damage, inhibiting PI3K/AKT signaling pathway, immunogenic cell death (ICD) and inhibit the cell growth at G2/M phase.

Dibutyl phthalate affects insulin synthesis and secretion by regulating the mitochondrial apoptotic pathway and oxidative stress in rat insulinoma cells.

Dibutyl phthalate (DBP) is a typical phthalate (PAEs). The environmental health risks of DBP have gradually attracted attention due to the common use in the production of plastics, cosmetics and skin care products. DBP was associated with diabetes, but its mechanism is not clear. In this study, an in vitro culture system of rat insulinoma (INS-1) cells was established to explore the effect of DBP on insulin synthesis and secretion and the potential mechanisms. INS-1 cells were cultured in RPMI-1640 medium containing 10% fetal bovine serum and treated with 15, 30, 60 and 120 µmol/L of DBP and dimethyl sulfoxide (vehicle, < 0.1%) for 24 h. The contents of insulin in the intracellular fluid and the extracellular fluid of the cells were measured. The results showed that insulin synthesis and secretion in INS-1 cells were significantly decreased in 120 µmol/L DBP group. The apoptosis rate and mitochondrial membrane potential of INS-1 cells were measured by flow cytometry with annexin V-FITC conjugate and PI, and JC-1, respectively. The results showed that DBP caused an increase in the apoptosis rate and a significant decrease in the mitochondrial membrane potential in INS-1 cells in 60 µmol/L and 120 µmol/L DBP group. The results of western blot showed that the expression of Bax/Bcl-2, caspase-3, caspase-9 and Cyt-C were significantly increased. Meanwhile, the level of oxidative stress in INS-1 cells was detected by fluorescent probes DCFH-DA and western blot. With the increase of DBP exposure, the oxidative stress levels (MDA, GSH/GSSG) were increased; and the antioxidant index (SOD) levels were decreased. Our experimental results provide reliable evidence that DBP induced apoptosis and functional impairment in INS-1 cells through the mitochondrial apoptotic pathway and oxidative stress. Therefore, we hypothesized that interference with these two pathways could be considered in the development of preventive protection measures.

Hepatic ROS Mediated Macrophage Activation Is Responsible for Irinotecan Induced Liver Injury.

Irinotecan is the first line chemotherapy drug used for treatment of metastatic colorectal cancer worldwide. There is increasing evidence suggesting that liver damage, including steatosis and steatohepatitis, can be caused during the treatment involving irinotecan. However, molecular mechanisms by which irinotecan-induced liver injury remain elusive. In this study, we found that irinotecan treatment caused significant elevation of ALT, inflammation, and fat accumulation in the liver, which are associated with hepatic macrophage activation. Depletion of macrophages by clodronate liposome improved irinotecan induced liver injury and inflammatory response in mice. In vitro data indicated that irinotecan induced intracellular ROS production in primary hepatocyte and upregulating of toll-like receptor (TLRs) family expression in macrophages. Supernatant from irinotecan treated hepatocyte triggered macrophage activation and upregulation of TLRs in macrophage, and N-acetylcysteine (NAC) abolished these effects. By using co-culture system, we further revealed that irinotecan activated macrophage induced impairment of lipid metabolism and promoted apoptosis in hepatocyte and NAC prevented macrophage-induced cell death and partially revered impaired lipid metabolism in hepatocytes. By using the irinotecan liver injury model, we demonstrated that combining NAC with irinotecan prevented irinotecan-induced macrophage activation, TLR upregulation, liver injury, and partially prevented the accumulation of triglycerides in liver. Our results thus indicated that macrophages play a critical role in irinotecan-induced liver injury, and targeting ROS provides new options for development of hepatoprotective drugs in clinical practice.

The autophagy-related proteins FvAtg4 and FvAtg8 are involved in virulence and fumonisin biosynthesis in Fusarium verticillioides.

Autophagy is the main intracellular degradation system by which cytoplasmic materials are transported to and degraded in the vacuole/lysosome of eukaryotic cells, and it also controls cellular differentiation and virulence in a variety of filamentous fungi. However, the contribution of the autophagic pathway to fungal development and pathogenicity in the important maize pathogen and mycotoxigenic fungus Fusarium verticillioides is still unknown. In this study, we characterized two autophagy-related proteins, FvAtg4 and FvAtg8. The F. verticillioides deletion mutants ΔFvAtg4 and ΔFvAtg8 were impaired in autophagosome formation, aerial hyphal formation, sexual growth, lipid turnover, pigmentation and fungal virulence. Interestingly, ΔFvAtg4 and ΔFvAtg8 were defective in fumonisin B1 (FB1) synthesis, which may have resulted from decreased intracellular levels of alanine in the mutants. Our results indicate that FvAtg4 and FvAtg8 contribute to F. verticillioides pathogenicity by regulating the autophagic pathway to control lipid turnover, fumonisin biosynthesis, and pigmentation during its infectious cycle.

Mycosubtilin Produced by Bacillus subtilis ATCC6633 Inhibits Growth and Mycotoxin Biosynthesis of Fusarium graminearum and Fusarium verticillioides.

Fusarium graminearum and Fusarium verticillioides are fungal pathogens that cause diseases in cereal crops, such as Fusarium head blight (FHB), seedling blight, and stalk rot. They also produce a variety of mycotoxins that reduce crop yields and threaten human and animal health. Several strategies for controlling these diseases have been developed. However, due to a lack of resistant cultivars and the hazards of chemical fungicides, efforts are now focused on the biocontrol of plant diseases, which is a more sustainable and environmentally friendly approach. In the present study, the lipopeptide mycosubtilin purified from Bacillus subtilis ATCC6633 significantly suppressed the growth of F. graminearum PH-1 and F. verticillioides 7600 in vitro. Mycosubtilin caused the destruction and deformation of plasma membranes and cell walls in F. graminearum hyphae. Additionally, mycosubtilin inhibited conidial spore formation and germination of both fungi in a dose-dependent manner. In planta experiments demonstrated the ability of mycosubtilin to control the adverse effects caused by F. graminearum and F. verticillioides on wheat heads and maize kernels, respectively. Mycosubtilin significantly decreased the production of deoxynivalenol (DON) and B-series fumonisins (FB1, FB2 and FB3) in infected grains, with inhibition rates of 48.92, 48.48, 52.42, and 59.44%, respectively. The qRT-PCR analysis showed that mycosubtilin significantly downregulated genes involved in mycotoxin biosynthesis. In conclusion, mycosubtilin produced by B. subtilis ATCC6633 was shown to have potential as a biological agent to control plant diseases and Fusarium toxin contamination caused by F. graminearum and F. verticillioides.

Systematic evaluation of the antitumor activity of three ruthenium polypyridyl complexes.

Ruthenium-containing complexes have emerged as good alternative to the currently used platinum-containing drugs for malignant tumor therapy. In this work, cytotoxic effects of recently synthesized ruthenium polypyridyl complexes [Ru(bpy)2(CFPIP)](ClO4)2 (bpy = 2,2'-bipyridine, CFPIP = (E)-2-(4-fluorostyryl)-1H-imidazo[4,5-f][1,10]phenanthroline, Ru(II)-1), [Ru(phen)2(CFPIP)](ClO4)2 (phen = 1,10-phenanthroline, Ru(II)-2) and [Ru(dmb)2(CFPIP)](ClO4)2 (dmb = 4,4'-dimethyl-2,2'-bipyridine, Ru(II)-3) toward different tumor cells were investigated in vitro and compared with cisplatin, the most widely used chemotherapeutic drug against hepatocellular carcinoma (HepG-2). The results demonstrate that target complexes show excellent cytotoxicity against HepG-2 cells with low IC50 value of 21.4 ± 1.5, 18.0 ± 2.1 and 22.3 ± 1.7 µM, respectively. It was important noting that target Ru(II) complexes exhibited better antitumor activity than cisplatin (IC50 = 28.5 ± 2.4 µM) against HepG-2 cells, and has no obvious toxicity to normal cell LO2. DNA binding results suggest that Ru(II)-1, Ru(II)-2 and Ru(II)-3 interact with CT DNA (calf thymus DNA) through intercalative mode. Complexes exerted its antitumor activity through increasing anti-migration and inducing cell cycle arrest at the S phase. In addition, the apoptosis was tested by AO (acridine orange)/EB (ethidium bromide) staining and flow cytometry. Mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and colocalization tests were also evaluated by ImageXpress Micro XLS system. Overall, the results show that the ruthenium polypyridyl complexes induce apoptosis in HepG-2 cells through ROS-mediated mitochondria dysfunction pathway.

Iridium(III)-BBIP complexes induce apoptosis via PI3K/AKT/mTOR pathway and inhibit A549 lung tumor growth in vivo.

The new ligand BBIP (BBIP = 2-(7-bromo-2H-benzo[d]imidazole-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline) with its iridium(III) complexes: [Ir(ppy)2(BBIP)](PF6) (ppy = 2-phenylpyridine, Ir1), [Ir(bzq)2(BBIP)](PF6) (bzq = benzo[h]quinolone, Ir2) and [Ir(piq)2(BBIP)](PF6) (piq = 1-phenylisoquinoline, Ir3) were synthesized and characterized by elemental analysis, High Resolution Mass Spectrometer (HRMS), 1H NMR and 13C{1H} NMR. The cytotoxicity of the complexes against A549, HepG2, SGC-7901, BEL-7402, HeLa and normal LO2 was evaluated through 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide (MTT) method. The results show that Ir1 exhibits high cytotoxic activity against A549 cells with a low IC50 value of 4.9 ± 0.5 µM. A series of biological activities such as cell cycle arrest, endoplasmic reticulum localization assay, apoptosis, western blotting, cellular uptake determination and in vivo antitumor activity were investigated. The assays implied that the complexes inhibit cancer cell migration through blocking mitotic progress. Cell cycle distribution stated that the complexes depress cell growth at G0/G1 phase. Additionally, the complexes acted on the endoplasmic reticulum and induce apoptosis through endoplasmic reticulum stress pathway. Especially, the western blotting showed that the complexes activated Bcl-2 (B-cell lymphoma-2) family and decreased PI3K (phosphoinositide-3 kinase) and AKT (protein kinase B), up-regulated the expression of mTOR (mammalian target of rapamycin) and p-mTOR (phosphorylated mammalian target of rapamycin). Therefore, the complexes induce apoptosis through activating PI3K-AKT-mTOR pathway. Antitumor in vivo demonstrated that Ir1 can effectively prevent the tumor growth with an inhibitory rate of 48.89%.

Studies of anticancer activity in vivo and in vitro behaviors of liposomes encapsulated iridium(III) complex.

Iridium(III) complexes have gained great attention in cancer treatment in recent years. In this paper, we designed and synthesized a new iridium(III) complex [Ir(piq)2(DQTT)](PF6) Ir1 (piq = 1-phenylisoquinoline, DQTT = 12-(1,4-dihydroquinoxalin-6-yl)-4,5,9,14-tetraazabenzo[b]triphenylene). The Ir1-loaded PEGylated liposomes (Lipo-Ir1) were prepared using the ethanol injection method. The anticancer activity of the complex and Lipo-Ir1 against SGC-7901 (human gastric adenocarcinoma), A549 (human lung carcinoma), HeLa (human cervical carcinoma), HepG2 (human hepatocellular carcinoma), BEL-7402 (human hepatocellular carcinoma), and normal NIH3T3 (mouse embryonic fibroblasts) was tested by the MTT method. The complex Ir1 shows moderate or low cytotoxicity against the selected cancer cells, whereas the Lipo-Ir1 exhibits high anticancer activity toward the same cancer cells. The apoptosis induced by Lipo-Ir1 was assayed by flow cytometry and Lipo-Ir1 induced apoptosis through increasing intracellular reactive-oxygen species levels, decreasing mitochondrial membrane potential, further promoting cytochrome c release and causing the increase of level of intracellular Ca2+. Western blot was used to detect the changes in Bcl-2 family protein and PI3K/AKT pathway proteins. The cloning experiments demonstrated that the Lipo-Ir1 can effectively inhibit cell proliferation. In vivo experiments, Lipo-Ir1 inhibited tumor growth in xenograft nude mice, and the percentage of tumor growth inhibition in vivo was 75.70%. Overall, the liposomes Lipo-Ir1 exhibits higher anticancer activity than Ir1 under the same conditions. These results indicated that Lipo-Ir1 may be a valuable resource for cancer therapy.

Liposome as drug delivery system enhance anticancer activity of iridium (III) complex.

Herein an Ir(III) complex [Ir(Hppy)2(HMNPIP)](PF6) (Ir1, Hppy = 2-phenylpyridine, HMNPIP = 2-(1H-imidazo[4,5-f][1, 10]phenanthroline-3-yl)-6-methoxy-4-nitrophenol) was prepared and characterized. Due to the low anticancer activity of Ir1 when administered free drug, we prepared a liposome Ir1Lipo encapsulated form of Ir1 to improve the antitumor effect, furthermore, we explored the antitumor mechanism of both forms in vitro experiments on HepG2 cells. We investigated the inhibitory efficiency of Ir1 and Ir1Lipo on cell viability and proliferation using MTT (MTT = 3-(4,5-dimethylthiazole)-2,5-diphenltetraazolium bromide) and colony-forming assay. Intracellular accumulation of reactive oxygen species (ROS) was examined using a fluorescence microscope (High Content Screening System, ImageXpress Micro XLS System, Molecular Devices LLC, Sunnyvale, CA), programmed cell death cells stained with acridine orange/ethidium bromide (AO/EB) using flow cytometry detection and western blot have been performed. An in vivo study where HepG2 cells were transplanted into nude nice as xenografts. Tumour volume and body weight were monitored during the 10 days of administration. After encapsulation in liposomes Ir1Lipo displayed high potency against a variety of tumour cells in vitro, especially against HepG2 (IC50 = 4.6 ± 0.5 µM). Mechanism studies indicated that Ir1Lipo initiated apoptosis by generating intracellular ROS that regulate lysosomal-mitochondrial dysfunction, followed by microtubule disruption that subsequently leads to a G0/G1 phase of cell cycle arrest. Additionally, Ir1Lipo significantly curbed tumour growth in nude mice. The tumour inhibitory rate was 51.2% (5.6 mg/kg). Therefore, liposome as a drug delivery system greatly enhances anticancer activity of Ir1 by a factor of relatively minor side effects.

Exploring anticancer efficiency of mitochondria-targeted cyclometalated iridium(III) complexes.

We prepared and characterized new iridium(III) complexes: [Ir(NC)2(MPPIP)](PF6) (N-C = 2-phenylpyridine 1; benzo[h]quinolone 2; 1-phenylisoquinolone, 3, MPPIP = 2-(4-(4'-methylpiperazin-yl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline). MTT (MTT = 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide) method was used to assay anticancer activities of the complexes 1-3 toward SGC-7901, HeLa, A549, BEL-7402, mouse embryonic fibroblast NIH3T3 cell lines. Complexes 1, 2, 3 are sensitive to A549 cells and display a relatively low IC50 value of 5.4 ±â€¯0.3, 4.2 ±â€¯0.03 and 3.8 ±â€¯0.2 µM, respectively. The apoptotic efficiency was investigated and the number of apoptotic cells induced by 1, 2 and 3 is 9.92%, 11.30% and 16.00%. The complexes are able to increase intracellular ROS content and lessen the mitochondrial membrane potential. Besides, anti-tumor activity in vivo reveals that complex 3 exhibits moderate effect on inhibiting the tumor growth, and complex 3 has no influence on liver, brain, kidney, lung and heart.