Discovery of novel anaplastic lymphoma kinase (ALK) and histone deacetylase (HDAC) dual inhibitors exhibiting antiproliferative activity against non-small cell lung cancer

A series of novel benzimidazole derivatives were designed and synthesised based on the structures of reported oral available ALK inhibitor and HDAC inhibitor, pracinostat. In enzymatic assays, compound 3b, containing a 2-acyliminobenzimidazole moiety and hydroxamic acid side chain, could inhibit both ALK and HDAC6 (IC50 = 16 nM and 1.03 µM, respectively). Compound 3b also inhibited various ALK mutants known to be involved in crizotinib resistance, including mutant L1196M (IC50, 4.9 nM). Moreover, 3b inhibited the proliferation of several cancer cell lines, including ALK-addicted H2228 cells. To evaluate its potential for treating cancers in vivo, 3b was used in a human A549 xenograft model with BALB/c nude mice. At 20 mg/kg, 3b inhibited tumour growth by 85% yet had a negligible effect on mean body weight. These results suggest a attracting route for the further research and optimisation of dual ALK/HDAC inhibitors.

A novel HDAC6 inhibitor interferes microtubule dynamics and spindle assembly checkpoint and sensitizes cisplatin-induced apoptosis in castration-resistant prostate cancer

BACKGROUND

Metastatic castration-resistant prostate cancer (CRPC), the most refractory prostate cancer, inevitably progresses and becomes unresponsive to hormone therapy, revealing a pressing unmet need for this disease. Novel agents targeting HDAC6 and microtubule dynamics can be a potential anti-CRPC strategy.

METHODS

Cell proliferation was examined in CRPC PC-3 and DU-145 cells using sulforhodamine B assay and anchorage-dependent colony formation assay. Flow cytometric analysis of propidium iodide staining was used to determine cell-cycle progression. Cell-based tubulin polymerization assay and confocal immunofluorescence microscopic examination determine microtubule assembly/disassembly status. Protein expressions were determined using Western blot analysis.

RESULTS

A total of 82 novel derivatives targeting HDAC6 were designed and synthesized, and Compound 25202 stood out, showing the highest efficacy in blocking HDAC6 (IC50, 3.5 nM in enzyme assay; IC50, 1.0 μM in antiproliferative assay in CRPC cells), superior to tubastatin A (IC50, 5.4 μM in antiproliferative assay). The selectivity and superiority of 25202 were validated by examining the acetylation of both α-tubulin and histone H3, detecting cell apoptosis and HDACs enzyme activity assessment. Notably, 25202 but not tubastatin A significantly decreased HDAC6 protein expression. 25202 prolonged mitotic arrest through the detection of cyclin B1 upregulation, Cdk1 activation, mitotic phosphoprotein levels, and Bcl-2 phosphorylation. Compound 25202 did not mimic docetaxel in inducing tubulin polymerization but disrupted microtubule organization. Compound 25202 also increased the phosphorylation of CDC20, BUB1, and BUBR1, indicating the activation of the spindle assembly checkpoint (SAC). Moreover, 25202 profoundly sensitized cisplatin-induced cell death through impairment of cisplatin-evoked DNA damage response and DNA repair in both ATR-Chk1 and ATM-Chk2 pathways.

CONCLUSION

The data suggest that 25202 is a novel selective and potent HDAC6 inhibitor. Compound 25202 blocks HDAC6 activity and interferes microtubule dynamics, leading to SAC activation and mitotic arrest prolongation that eventually cause apoptosis of CRPC cells. Furthermore, 25202 sensitizes cisplatin-induced cell apoptosis through impeding DNA damage repair pathways.

Discovery of HDAC6, HDAC8, and 6/8 Inhibitors and Development of Cell-Based Drug Screening Models for the Treatment of TGF-β-Induced Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis is incurable, and its progression is difficult to control and thus can lead to pulmonary deterioration. Pan-histone deacetylase inhibitors such as SAHA have shown potential for modulating pulmonary fibrosis yet with off-target effects. Therefore, selective HDAC inhibitors would be beneficial for reducing side effects. Toward this goal, we designed and synthesized 24 novel HDAC6, HDAC8, or dual HDAC6/8 inhibitors and established a two-stage screening platform to rapidly screen for HDAC inhibitors that effectively mitigate TGF-β-induced pulmonary fibrosis. The first stage consisted of a mouse NIH-3T3 fibroblast prescreen and yielded five hits. In the second stage, human pulmonary fibroblasts (HPFs) were used, and four out of the five hits were tested for caco-2 permeability and liver microsome stability to give two potential leads: J27644 (15) and 20. This novel two-stage screen platform will accelerate the discovery and reduce the cost of developing HDAC inhibitors to mitigate TGF-β-induced pulmonary fibrosis.

Current status of soil and groundwater remediation technologies in Taiwan

The purpose of this review is the analysis of the soil and groundwater remediation technologies referred as in situ chemical oxidation and phytoremediation, and to discuss the successes that have been made. The technology of phytoremediation has yet to be commercially accepted but shows emerging capabilities. In situ chemical oxidation (ISCO) is a frequently used technology in Taiwan for the remediation of organic compounds. Several studies have been conducted in Taiwan so show their feasibility and potential. This article reviews studies concerning these two remediation technologies. Other processes such as monitored natural attenuation, flushing, thermal treatment, or soil washing are not covered within this article.

Organic matter and nitrogen removal within field-scale constructed wetlands: reduction performance and microbial identification studies

This study investigated organic matter and nitrogen reduction and transformation mechanisms within a field-scale hybrid natural purification system. The system included an oxidation pond, two serial surface-flow wetlands with a cascade in between, and a subsurface-flow wetland receiving secondary treated dormitory sewage. The average biochemical oxygen demand (BOD) and chemical oxygen demand (COD) removal was 81 and 48%, respectively. Microbial degradation was the primary process contributing to organic reduction. Total Kjeldahl nitrogen (TKN) and ammonium decreased from 7.1 to 3.9 and 5.58 to 3.25 mg/L, respectively, within the surface-flow wetlands. The results indicated that nitrification occurred within the aerobic compartments. The nitrate levels continued to decrease from 1.26 to 1.07 mg/L, indicating nitrate reduction occurred in the surface-flow wetland. Total nitrogen decreased from 8.61 to 5.12 mg/L, equivalent to a 41% reduction, within the surface-flow wetlands. Results revealed that denitrification might concurrently occur in the compartment of surface-flow wetland. Total nitrogen continued to decrease from 5.12 to 3.99 mg/L within the anoxic subsurface-flow wetlands through denitrification transformation. The significant total nitrogen reduction observed was 65%. The predominant reduction of total nitrogen might take place within the sediment of surface flow and the subsurface-flow wetland where denitrification occurred. The microbial identification results also indicated that nitrification/denitrification might occur concurrently within the sediments of surface-flow wetlands. The results of this study show that hybrid wetland systems are a viable option for organic matter and nitrogen transformation and removal in tropical regions where tertiary wastewater systems are too costly or unable to operate. Treated water from these systems can comply with local surface water criteria rendering water for reuse and groundwater recharge.

Application of surfactant enhanced permanganate oxidation and bidegradation of trichloroethylene in groundwater

The industrial solvent trichloroethylene (TCE) is among the most ubiquitous chlorinated solvents found in groundwater contamination. The main objectives of this study were to evaluate the feasibility of using non-ionic surfactant Simple Green (SG) to enhance the oxidative dechlorination of TCE by potassium permanganate (KMnO4) employing a continuous stir batch reactor system (CSBR) and column experiments. The effect of using surfactant SG to enhance the biodegradation of TCE via aerobic cometabolism was also examined. Results from CSBR experiments revealed that combination of KMnO4 with surfactant SG significantly enhanced contaminant removal, particularly when the surfactant SG concentrated at its CMC. TCE degradation rates ranged from 74.1% to 85.7% without addition of surfactant SG while TCE degradation rates increased to ranging from 83.8% to 96.3% with presence of 0.1wt% SG. Furthermore, results from column experiments showed that TCE was degraded from 38.1microM to 6.2microM in equivalent to 83.7% of TCE oxidation during first 560min reaction. This study has also demonstrated that the addition of surfactant SG is a feasible method to enhance bioremediation efficiency for TCE contaminated groundwater. The complete TCE degradation was detected after 75 days of incubation with both 0.01 and 0.1wt% of surfactant SG addition. Results revealed that surfactant enhanced chemical oxidation and bioremediation technology is one of feasible approaches to clean up TCE contaminated groundwater.

Pollutant removal within hybrid constructed wetland systems in tropical regions

Hybrid constructed wetlands have received tremendous interests for water quality enhancement due to insufficient sewage treatment and groundwater deterioration in Taiwan. The main objectives of this study were to investigate pollutant removal efficiencies and mechanisms within field-scale hybrid natural purification systems. The studied hybrid constructed wetland systems include an oxidation pond, two serial surface flow wetlands with a cascade in between, and a subsurface flow wetland receiving secondary treated dormitory sewage. The average SS, BOD and COD percent removal efficiency was 86.7, 86.5 and 57.8%, respectively. The ratio of BOD to COD decreased from 0.65 in the initial aerobic compartment to 0.21 in anoxic parts of the systems, indicating most biological degradable materials were decomposed in the aerobic oxidation pond and surface flow wetlands. Heavy metal removal percentages of copper and zinc were 72.9 and 68.3%, respectively. Sedimentation and plant uptake are the possible sinks for metals retention. Significant phosphorus removal was not achieved in this study. Total Kjeldahl nitrogen (TKN) and ammonium decreased from 4.08 to 1.43 and 3.74 to 1.21 mg/L, respectively, while nitrate nitrogen increased from 1.91 to 3.85 mg/L within the aerobic oxidation pond and surface flow wetlands. This result demonstrated nitrification occurring within aerobic compartments. The nitrate nitrogen continued to decrease from 3.85 to 1.43 mg/L within the anoxic subsurface wetlands mainly through denitrification transformation. Total nitrogen removal was from 7.61 to 3.61 mg/L, with the percentage removal of total nitrogen around 52.6%. The primary nitrogen removal and transformation mechanisms within the studied wetland systems were nitrification within aerobic followed by denitrificaiton within anaerobic systems. The emergent macrophytes enhance aeration through oxygen transferring that attributing the higher organic matter removal and nitrification rate. The hybrid wetland systems are viable options of pollutants transformation and removal in tropical countries, while tertiary wastewater systems are too costly or unable to operate. Effluent of purified systems can comply with local surface water criteria rendering for groundwater recharge.

Application of a constructed wetland for industrial wastewater treatment: a pilot-scale study

The main objective of this study was to examine the efficacy and capacity of using constructed wetlands on industrial pollutant removal. Four parallel pilot-scale modified free water surface (FWS) constructed wetland systems [dimension for each system: 4-m (L)x1-m (W)x1-m (D)] were installed inside an industrial park for conducting the proposed treatability study. The averaged influent contains approximately 170 mg l(-1) chemical oxygen demand (COD), 80 mg l(-1) biochemical oxygen demand (BOD), 90 mg l(-1) suspend solid (SS), and 32 mg l(-1) NH(3)-N. In the plant-selection study, four different wetland plant species including floating plants [Pistia stratiotes L. (P. stratiotes) and Ipomoea aquatica (I. aquatica)] and emergent plants [Phragmites communis L. (P. communis) and Typha orientalis Presl. (T. orientalis)] were evaluated. Results show that only the emergent plant (P. communis) could survive and reproduce with a continuous feed of 0.4m(3)d(-1) of the raw wastewater. Thus, P. communis was used in the subsequent treatment study. Two different control parameters including hydraulic retention time (HRT) (3, 5, and 7d) and media [vesicles ceramic bioballs and small gravels, 1cm in diameter] were examined in the treatment study. Results indicate that the system with a 5-d HRT (feed rate of 0.4m(3)d(-1)) and vesicles ceramic bioballs as the media had the acceptable and optimal pollutant removal efficiency. If operated under conditions of the above parameters, the pilot-plant wetland system can achieve removal of 61% COD, 89% BOD, 81% SS, 35% TP, and 56% NH(3)-N. The treated wastewater meets the current industrial wastewater discharge standards in Taiwan.

Evaluation of natural and enhanced PCP biodegradation at a former pesticide manufacturing plant

Pentachlorophenol (PCP) has been used in the past as a pesticide, herbicide, antifungal agent, bactericide, and wood preservative. Thus, PCP is among the most ubiquitous chlorinated compounds found in groundwater contamination. A former pesticide manufacturing plant located in southern Taiwan has been identified as a PCP spill site. In this study, groundwater samples collected from the PCP site were analyzed to assess the occurrence of natural PCP biodegradation. Microcosm experiments were conducted to (1) evaluate the feasibility of biodegrading PCP by indigenous microbial consortia under aerobic and cometabolic conditions, and (2) determine the potential of enhancing PCP biodegradation using cane molasses and biological sludge cake as the substitute primary substrates under cometabolic conditions. The inocula used in this microcosm study were aquifer sediments collected from the PCP site and activated sludges collected from the municipal and industrial wastewater treatment plants. Results from this field investigation indicate that the natural biodegradation of PCP is occurring and causing the decrease in PCP concentration. Microcosm results show that the indigenous microorganisms can biodegrade PCP under both aerobic and aerobic cometabolism conditions. A PCP-degrading bacterium was isolated from the collected aquifer sediments and identified as Pseudomonas mendocina NSYSU via some biochemical tests and further conformation of DNA sequencing. In batch cultures, P. mendocina NSYSU used PCP as its sole source of carbon and energy. The isolated bacterium, P. mendocina NSYSU, was capable of completely degrading PCP as indicated by the increase in biomass formation with the decrease in PCP concentrations occurred in the carbon-free medium simultaneously. Results indicate that the in situ or on-site aerobic bioremediation using indigenous microorganisms or inoculated bacteria would be a feasible technology to clean up the studied PCP-contaminated site. Results from this study will be useful in designing a scale-up in situ or on-site PCP bioremediation system (e.g., on-site bioreactor) for field application.

Enhanced PCE dechlorination by biobarrier systems under different redox conditions

The industrial solvent tetrachloroethylene (PCE) is among the most ubiquitous chlorinated compounds found in groundwater contamination. The objective of this study was to evaluate the (1) feasibility of enhancing PCE biodegradation using cane molasses and sludge cakes as the primary substrates under methanogenic and iron reducing conditions, and (2) potential of installation a sludge cake/cane molasses biobarrier to clean up PCE-contaminated aquifers. The biodegradability of sludge cake (from secondary wastewater treatment system) and cane molasses was tested using bioavailability experiments. Results show that biodegradable materials were released from sludge cake/cane molasses and utilized by microbial consortia. Based on the chemical oxygen demand (COD) tests, approximately 28 and 248 mg of biodegradable COD can be released from 1g of sludge cake and 1g of cane molasses under anaerobic conditions, which have the potential to convert 70 and 620 mg of PCE to ethylene (ETH), respectively. Reductive dechlorination was evaluated using microcosms containing primary substrates (sludge cake/cane molasses) and inocula (aquifer sediments). Results indicate that sludge cake and cane molasses can serve as the diffusion sources of primary substrates, and enhance the reductive dechlorination of PCE under methanogenic processes. However, results from this study were not sufficient enough to show that reductive dechlorination of PCE would occur under iron-reducing conditions. This indicates that more studies need to be performed to further evaluate the role of iron reduction on the PCE dechlorination. Results reveal that it is feasible and applicable to install a sludge cake or cane molasses biobarrier to clean up PCE contaminated aquifers. From an engineering point of view, the sludge cake/cane molasses biobarrier has the potential to become an environmentally and economically acceptable technology for PCE bioremediation.

A defective RNA associated with bamboo mosaic virus and the possible common mechanisms for RNA recombination in potexviruses

A naturally occurring 1.1 kb RNA was isolated from purified virions of bamboo mosaic potexvirus isolate S (BaMV-S). This RNA is a defective RNA (D RNA) derived from a single internal deletion of the BaMV genome. A cDNA clone representing the complete nucleotide sequence of the BaMV-S D RNA was generated and its nucleotide sequence was determined. The BaMV D cDNA is 1015 nts in length [excluding the poly(A) tail] and consists of two regions corresponding to 867 nts of the 5' terminus and 148 nts of the 3' terminus of the BaMV genomic RNA. BaMV D cDNA contains a single open reading frame (ORF) encoding a putative 29.7 kDa protein comprised of a fusion of the first 258 amino acids of BaMV ORF 1 and the last 2 amino acids of coat protein. The coding capacity of D RNA was verified by in vitro translation of native BaMV-S D RNA and of 1.1 kb RNA transcribed in vitro from the full-length D cDNA. BaMV D RNA can be reproducibly generated by serial passages of BaMV-S in Nicotiana benthamiana and is the first D RNA in the potexvirus group shown to be generated de novo. Alignments of sequences surrounding the 5' and 3' junction borders of reported potexvirus D RNAs reveal a 65.2-84.6% sequence identity, suggesting that common mechanisms for viral RNA recombination are involved in the generation of potexvirus D RNAs.