The response mechanism analysis of HMX1 knockout strain to levulinic acid in Saccharomyces cerevisiae.

Levulinic acid, a hydrolysis product of lignocellulose, can be metabolized into important compounds in the field of medicine and pesticides by engineered strains of Saccharomyces cerevisiae. Levulinic acid, as an intermediate product widely found in the conversion process of lignocellulosic biomass, has multiple applications. However, its toxicity to Saccharomyces cerevisiae reduces its conversion efficiency, so screening Saccharomyces cerevisiae genes that can tolerate levulinic acid becomes the key. By creating a whole-genome knockout library and bioinformatics analysis, this study used the phenotypic characteristics of cells as the basis for screening and found the HMX1 gene that is highly sensitive to levulinic acid in the oxidative stress pathway. After knocking out HMX1 and treating with levulinic acid, the omics data of the strain revealed that multiple affected pathways, especially the expression of 14 genes related to the cell wall and membrane system, were significantly downregulated. The levels of acetyl-CoA and riboflavin decreased by 1.02-fold and 1.44-fold, respectively, while the content of pantothenic acid increased. These findings indicate that the cell wall-membrane system, as well as the metabolism of acetyl-CoA and riboflavin, are important in improving the resistance of Saccharomyces cerevisiae to levulinic acid. They provide theoretical support for enhancing the tolerance of microorganisms to levulinic acid, which is significant for optimizing the conversion process of lignocellulosic biomass to levulinic acid.

Modified high-efficiency carbon material for deep degradation of phenol by activating persulfate.

A series of cobalt-nitrogen modified catalysts were prepared and applied to the degradation of phenol. The Mott Schottky catalyst (CoO/NGr@C) with high pyridine nitrogen content was designed to activate potassium peroxodisulfate (PDS) to generate active free radicals for phenol degradation. The structural properties of the materials are analyzed by XPS, TEM and then the charge density calculation is performed by DFT, which proves the existence of the highly active interface effect. Co-N-CMCM-41 can only degrade phenol into benzoquinone and it is difficult to achieve further degradation of benzoquinone, while the modified CoO/NGr@C can achieve deep mineralization of the intermediate benzoquinone through UV spectrum. EPR was used to prove that both hydroxyl radicals and sulfate radicals exist in the degradation process of phenol. Through the DFT simulation calculation of the material, it is proved that the existence of carbon activated by nitrogen and the electron rearrangement between cobalt and nitrogen-rich carbon lead to the catalytic activity of the material. The degradation conditions of phenol were optimized and the reaction kinetics of further phenol degradation were studied. The activation energy of phenol degradation on CoO/NGr@C is calculated to be 34.38 kJ mol-1.

Oxidative esterification of renewable furfural on cobalt dispersed on ordered porous nitrogen-doped carbon.

A series of highly dispersed cobalt-based catalysts on N-doped ordered porous carbon (Co-NOPC) were synthesized using the sacrificial-template method. MCM-41, ZSM-5 and SBA-15 were employed as hard templates with 2,2'-bipyridine as the ligand. The physical and chemical properties of the Co-NOPC catalyst were characterized by Raman, XRD, SEM, TEM, EDX, ICP, BET, XPS. Co-NOPC had been proven to be a highly efficient catalyst for oxidative esterification of furfural (FUR) to methyl 2-furoate without alkaline additives. Catalytic performance was correlated to the dispersed cobalt, porous structure and specific surface area. The relationship between oxygen activation and the strong interaction of cobalt and pyridine nitrogen were confirmed by XPS. Catalytic performance enhancement mechanisms were correlated with the redistribution of electrons at the interface between carbon material and cobalt atoms through the molecular dynamics method and a reaction mechanism was also proposed. The optimized catalysts showed outstanding catalytic activity and stability and no obvious decrease in activity was found after 6 cycles with 99.6% FUR conversion and 96% methyl 2-furoate selectivity.

Current Status in the Discovery of Covalent Janus Kinase 3 (JAK3) Inhibitors.

The search for inhibitors of the Janus kinase family (JAK1, JAK2, JAK3 and TYK2) has been ongoing for several decades and has resulted in a number of JAK inhibitors being approved for use in patients, such as tofacitinib for the treatment of autoimmune diseases such as Rheumatoid Arthritis (RA). Although initially thought to be a JAK3 selective inhibitor, tofacitinib was subsequently found to possess significant activity to inhibit JAK1 and JAK2 which has contributed to some adverse side effects. A selective JAK3 inhibitor should only have an effect within the immune system since JAK3 is solely expressed in lymphoid tissue; this makes JAK3 a target of interest in the search for treatments of autoimmune diseases. A method to obtain selectivity for JAK3 over the other JAK family members, which has attracted more scientific attention recently, is the targeting of the active site cysteine residue, unique in JAK3 within the JAK family, with compounds containing electrophilic warheads which can form a covalent bond with the nucleophilic thiol of the cysteine residue. This review encompasses the historical search for a covalent JAK3 inhibitor and the most recently published research which hasn't been reviewed to date. The most important compounds from the publications reviewed the activity and selectivity of these compounds together with some of the more important biological results are condensed in to an easily digested form that should prove useful for those interested in the field.

Selective Toxicity of a Highly Potent Camptothecin Analogue: A Pilot Study with Glioblastoma Multiforme Cells.

BACKGROUND/AIM: We developed a novel camptothecin analogue, CPT417, that yields reduced toxicity compared to other analogues used in chemotherapeutic regimens. In this pilot study, we assessed the activity of CPT417 against glioblastoma multiforme (GBM) cells and glioma stem cells. MATERIALS AND METHODS: The human U251 GBM cell line and normal human astrocytes were cultured in parallel for clonogenic survival analysis following exposure to increasing concentrations of CPT417. Cell viability of a glioma stem cell line was assessed 5 days after exposure to a range of CPT417 concentrations. RESULTS: CPT417 completely inhibited clonogenic survival of GBM cells at 10 nM, whereas this concentration only inhibited astrocytes by approximately 50%. Cell viability analysis of glioma stem cell cultures yielded a half-maximal response at 15 nM. CONCLUSION: CPT417 acts selectively against GBM cells at concentrations that are at least an order of magnitude below reported values for related alkylating agents in clinical use.

Current Status of Biological Therapies for the Treatment of Metastatic Melanoma.

Compared to early-stage melanoma when surgical excision is possible, metastatic disease continues to offer a much grimmer prognosis as traditional chemotherapy treatment regimens offer relatively little survival benefit. This has led to changes in treatment approaches over the preceding two decades as contemporary methods for the treatment of advanced or metastatic melanoma now involve a number of biological modalities, which include immunotherapeutic approaches, targeted therapies and epigenetic modification therapies. Clinically available immunotherapeutic agents include interleukin 2 (IL-2), as well as drugs targeting the important immune checkpoint molecules, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1). The targeted therapeutic agents modulate specific pro-oncogenic mutations such as v-Raf murine sarcoma viral oncogene homolog B (BRAF), receptor tyrosine kinases, MEK inhibitors and potential future therapeutic targets, such as the CDK4/CDK6, PTEN and GNAQ/GNA11 genes. Additionally, an increasing understanding of the role of epigenetic alterations in the development and progression of melanoma now offers a new potential drug target. Several of these agents have shown promising results; however, in many investigations, combinations of different therapeutic approaches, each with different mechanisms of action, have yielded improved outcomes as treatment regimens continue to be further optimized by active research and patient disease sub-group analyses. This review summarizes the novel biological agents and new treatments, directly contributing to the significant improvement of biological therapies and markedly advancing knowledge of clinical application of newly approved and developed therapies in treatment of patients with metastatic melanoma.

A Novel Microtubule-Disrupting Agent Induces Endoplasmic Reticular Stress-Mediated Cell Death in Human Hepatocellular Carcinoma Cells.

Here, we present evidence of a novel microtubule-disrupting agent, N-deacetyl-N-(chromone-2-carbonyl)-thiocolchicine (TCD), exhibiting potent antitumor activity (with IC50 values in the nanomolar range) against hepatocellular carcinoma cell lines. Cell cycle analysis revealed that TCD induced G2/M cell-cycle arrest in a dose- and time-dependent manner in both Hep-J5 and Mahlavu HCC cell lines. TCD also induced a decrease in mitochondrial membrane potential (ΔΨm) and caused DNA damage. Mechanistically, TCD activated protein kinase RNA-like endoplasmic reticular kinase and several transcription factors, including activating transcription factor (ATF) 6, ATF4, ATF3, and the CCAAT-enhancer binding protein homologous protein. These data clearly demonstrate that the antitumor activity of TCD is mechanistically linked to its capacity to trigger both intrinsic and extrinsic apoptotic cell death via endoplasmic reticular stress pathway. The potent antitumor activity of TCD was similarly demonstrated in a hepatocellular carcinoma xenograft model, where 5 and 10 mg/kg doses of TCD significantly arrested Hep-J5 and Mahlavu tumor growth. Our finding suggests that TCD is a promising therapeutic agent against hepatocellular carcinoma; further translational assessment of its clinical usage is warranted.

Recent developments in radiosensitization.

Radiation therapy is essential for local tumor control for many types of cancer histologies. Technological advancements in recent years have allowed for precise irradiation of target tissues while minimizing the dose to non-target tissues. To enhance radiation damage to cancer cells and further limit the radiation effects on normal tissue, researchers have explored compounds that specifically target cancer cells and make them more sensitive to ionizing radiation. Recent radiosensitization research has focused on promising compounds that alter hypoxia, inhibit topoisomerases, interfere with microtubules, and activate caspases, among other mechanisms. Many such compounds have shown impressive results in pre-clinical trials against a variety of cell types, but their safety, efficacy and practicability in clinical trials remains to be demonstrated. This review seeks to provide an overview of recent research in radiosensitization, detailing some of the more successful compounds, and illustrating avenues for future research.

Radiation-associated Cardiac Injury.

Chest radiotherapy continues to play an important role in the treatment of breast cancer, Hodgkin's lymphoma, and other malignancies. Subsequent cardiac injury has been described involving essentially all structures of the heart, with most radiation-induced injury being progressive in nature. Our understanding over the multifactorial etiology and development of radiation-associated cardiac injury has advanced, leading to improved techniques aimed at decreasing cardiac radiation exposure and associated risks. Monitoring after radiotherapy clearly appears to be indicated; however, optimal recommendations regarding cardiac screening remain difficult to establish.

Cardiotoxicity of molecular-targeted drug therapy.

Cardiotoxicity is a well-known side-effect described in patients receiving various antineoplastic agents. With the abundance of clinical research and a heavy focus on drug development over the past decade, there has been a major shift in the use of non-specific cytotoxic drugs to molecular-targeted drug therapy. However, as a result, it has become clear that these drugs have numerous adverse effects, both on-target and off-target. Small-molecule tyrosine kinase inhibitors and other molecular-targeted agents, including monoclonal antibodies, have been the primary agents associated with cardiotoxicity. As more molecular-targeted therapies are developed, early recognition and management of drug-related cardiotoxicity will be extremely important in order to reduce morbidity and mortality. Pre-treatment evaluation with a surface electrocardiogram, echocardiography, cardiac history, and comprehensive review of concomitant medications are the current mainstay of treatment. However, much is still unknown about the potential cardiotoxic side-effects of these drug and optimal management. In the present article, we aim to review the cardiovascular implications and related cardiotoxicities associated with molecular target-based chemotherapeutic agents, with special emphasis on hypertension, cardiac dysfunction, and QT prolongation. Their implication, mechanism, and management are discussed where possible.

Radioprotectants to reduce the risk of radiation-induced carcinogenesis.

PURPOSE: Development of radioprotective agents has focused primarily on cytoprotection from relatively high doses of therapeutic radiation and nuclear disasters. Epidemiological studies and radiobiological models report the potential for stochastic effects from relatively low-dose radiation exposure. Diagnostic studies like computed tomography (CT) expose the patient to a small but significant amount of radiation, which has been reported to increase the risk for carcinogenesis. Young patients expected to undergo multiple CT studies may benefit from a protective agent given prior to CT. This review includes published data of agents that have been shown to protect against radiation-induced carcinogenesis. A discussion follows regarding the data that describes the extent of radiation exposure during CT, as well as technical modifications, which also reduce radiation exposure. RESULTS/CONCLUSIONS: Most experiments have used in vivo animal models or in vitro cell lines. Ethical barriers prevent large-scale human studies, although, there are two prospective human studies from the Chernobyl nuclear accident. Collectively, all of these studies provide evidence of statistically significant reductions in radiation-induced carcinogenesis. Protection is achieved by several mechanisms, which include free radical scavenging, caloric restriction, non-steroidal anti-inflammatory agents, humoral factors, and an oxidative agent. Enhanced efficacy is achieved when targeting multiple mechanisms. The data presented provides the scientific foundation for future development of a radioprotectant that may reduce the risk of carcinogenesis from low-dose exposure when certain at-risk populations undergo diagnostic studies like CT.

Brentuximab vedotin: first-line agent for advanced Hodgkin lymphoma.

Hodgkin lymphoma (HL) is characterized by malignant Reed-Sternberg cells which express CD30. Current National Comprehensive Cancer Network guidelines for patients with advanced HL (stage III/IV disease) recommend adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD), or escalated bleomycin, etoposide, adriamycin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPP) as first-line regimens. ABVD appears to be as effective, with fewer side effects, as escalated BEACOPP. Escalated BEACOPP leads to a greater progression-free survival but no difference in overall survival. Recent advancements in technology have enabled an exciting shift to molecular-targeted cancer therapy. Brentuximab vedotin, a CD30-directed antibody conjugate, specifically targets malignant HL cells. It is approved by the Food and Drug Administration for the treatment of systemic anaplastic large-cell lymphoma and refractory HL that has progressed after autologous stem cell transplant, or after two prior multiagent chemotherapy regimens among patients ineligible to receive a transplant.

Current status in chemotherapy for advanced pancreatic adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal types of cancer in the United States. Surgical resection remains the only curative treatment, but fewer than 20% of patients qualify as candidates. The past two decades saw major changes in the treatment of advanced PDA, a shift of standard protocol from 5-fluorouracil to gemcitabine and gemcitabine-based combinations, the introduction of molecular target therapy and multi-agent regimens. However, even with advancements in medicine, PDA is still extremely resistant to currently available regimens, which results in poor prognosis, with only 5.2% of patients alive at three years. This provides a challenge to scientists as they seek to find the best active regimen with the least side-effects. In this article, we review the current recommended guidelines from the National Comprehensive Cancer Network. In addition, we highlight major clinical trials since 2011.

Twelve-month prostate-specific antigen values and perineural invasion as strong independent prognostic variables of long-term biochemical outcome after prostate seed brachytherapy.

PURPOSE: To determine whether post-treatment prostate-specific antigen (ptPSA) values at 12 months and other clinical parameters predict long-term PSA relapse-free survival (PRFS) following prostate seed brachytherapy. METHODS AND MATERIALS: Records of 204 hormone-naïve patients with localized adenocarcinoma of the prostate treated at St. Mary's Regional Medical Center in Reno, NV, and at Carson Tahoe Regional Medical Center in Carson City, NV, between 1998 and 2003, using I-125 or Pd-103 seed brachytherapy, were retrospectively analyzed. Treatment planning was done using a preplanned, modified peripheral loading technique. A total of 185 of 204 patients had PSA records at 12 months after implant. Variables included were age, initial pretreatment PSA, Gleason score, T stage, National Comprehensive Cancer Network (NCCN) risk group (RG), perineural invasion (PNI), external beam boost, dose, and ptPSA levels at 12 months with cutpoints at ≤1, 1.01 to 2.00, 2.01 to 3.00, and >3.00 ng/ml. RESULTS: Median follow-up was 80 months, and median age was 69 years. The numbers of patients stratified by NCCN low, intermediate, and high RG were 110:65:10, respectively. Monotherapy and boost prescription doses were 145 Gy and 110 Gy for I-125, and 125 Gy and 100 Gy for Pd-103 seeds, respectively. The median dose (D90) was 95.4% of the prescribed dose. The 5-year PRFS at the 12-months ptPSA levels of ≤1, 1.01 to 2.00, 2.01 to 3.00, and >3.00 ng/ml were 98.5%, 85.7%, 61.5%, and 22.2%, respectively. The 10-year PRFS at the 12-months ptPSA levels of ≤1 and 1.01 to 2.00 ng/ml were 90.5% and 85.7%, respectively. In multivariate analysis, both ptPSA and PNI were significant independent predictors of PRFS. Hazard ratios (HR) for ptPSA levels at ≤1, 1.01 to 2.00, 2.01 to 3.00, and >3.00 ng/ml at 12 months were 1, 4.96, 27.57, and 65.10, respectively. PNI had an HR of 6.1 (p=0.009). CONCLUSIONS: Presence of PNI and ptPSA values at 12 months are strong prognostic variables for long-term PRFS after definitive prostate brachytherapy seed implantation.

Improved chemotherapy for hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the fifth most common cancer and it is the third leading cause of cancer-related deaths worldwide. Once diagnosed with the disease, only 30-40% of patients are deemed eligible for curative intention with treatment modalities including surgical resection, liver transplantation, and chemoembolization. Eventually, most patients will receive some forms of chemotherapy in hope of prolonging life. Sorafenib is the first molecular inhibitor to be approved by the FDA for the treatment of advanced HCC. It is a tyrosine kinase inhibitor, targeting multiple molecular pathways. Prior to the arrival of sorafenib, doxorubicin was routinely used as a single drug for advanced HCC, but has shown inefficacy, with a response rate of about 15-20%. Other chemotherapy agents, such as epirubicin, cisplatin, 5-fluorouracil, etoposide and their combinations, demonstrate even lower efficacy. While being considered an advance over conventional chemotherapy, sorafenib only improves life expectancy approximately by 3 months over placebo. With that in mind, continuous efforts have been put into finding new targets and molecular pathways for possible new drug development. In this article, we summarize the current literature over the past year on chemotherapy treatment of advanced HCC.

Improved radiotherapy for primary and secondary liver cancer: stereotactic body radiation therapy.

BACKGROUND: Radiation therapy for primary and secondary liver cancer has been limited due to dose-limiting radiation-associated liver injury. Stereotactic body radiation therapy (SBRT) permits higher dose to tumors while minimizing radiation to uninvolved liver. The purpose of this study was to assess the efficacy and safety of SBRT for treating primary and secondary hepatic neoplasms. MATERIALS AND METHODS: We performed a systematic review of prospective clinical trials published in English. RESULTS: Fifteen studies involving 158 patients with primary tumors and 341 patients with metastases to the liver were included. Treatment was performed in 1-10 fractions to total doses of 18-60 Gy. One year local control and overall survival rates were 50-100% and 33-100% respectively. There were 13 cases of radiation-induced liver disease and 4 grade 5, 6 grade 4, and 69 grade 3 adverse events reported. CONCLUSION: For patients who are unable or unwilling to undergo local therapy, SBRT is safe and efficacious for treating primary and secondary liver cancer.

Novel chemoradiosensitizers for cancer therapy.

Combined modality therapy using both chemotherapy and radiation has proved superior over radiation therapy alone for a variety of cancer types. While the locoregional control and survival benefits have been established, there is still much room for improvement both in terms of cancer control and normal tissue toxicity, i.e. the therapeutic ratio. Recently, the pace of research and development of both conventional cytotoxic and molecularly targeted radiosensitizers has been staggering. The aim of this paper is to bring the reader up to date on the clinical status of four promising new radiosensitizers: novel camptothecin analogs and inhibitors of poly(ADP-ribose) polymerase, histone deacetylase, and heat-shock protein 90.

Enhancement of radiation-induced DNA damage and inhibition of its repair by a novel camptothecin analog.

A novel camptothecin derivative (TLC388) with higher efficacy and reduced toxicity has been synthesized and tested as a novel chemoradiosensitizing agent. This study investigated the mechanisms of the chemoradiosensitizing effects of TLC388 on H23 human non-small cell lung cancer (NSCLC) cells. Using the TUNEL assay, a significantly higher percentage of apoptotic cells was observed in the group treated with TLC388 plus X-ray radiation than those in groups treated with drug or radiation alone. The sensitizer enhancement ratio (SER) was 1.91. Apoptosis increased with drug concentration and radiation dose, exhibiting dose-dependent pattern. The results suggested that apoptosis could be a main mode of cell death that might underlie the increased chemoradio-sensitization of TLC388. Treatment with 30 nM of TLC388 plus 4 Gy X-ray also produced up to 42% of necrotic cells that were measured by trypan blue exclusion assay, but with TLC388 alone or 4 Gy radiation alone 9.8% or 11.1% necrotic cells were detected, respectively. An immunofluorescent staining method was employed to determine the levels of gamma-H2AX (phosphorylated H2AX, a variant of the H2A protein family, which is a component of the histone octomer in nucleosomes and is phosphorylated by kinases like ATM and ATR in the PI3K pathway, as the first step in recruiting and localizing DNA repair proteins) as a molecular biomarker of DNA double strand breaks (DSBs) in cells treated with TLC388 +/-radiation, or radiation alone. The formation of gamma-H2AX foci was observed after TLC388 or radiation exposure and when the cells were treated with 30 nM TLC388 plus radiation at a dose of 2 Gy, the percentage of cells containing gamma-H2AX foci increased significantly. Even more interesting, a markedly higher percentage (65.4%) of mitotic cells displayed gamma-H2AX foci after treatment with 30 nM TLC388 plus 0.5 Gy radiation, compared to only 5.9% or 26.1% of the M-phase cells treated with 30 nM TLC388 alone or 0.5 Gy radiation alone, respectively. It is suggested that mitotic cells become very sensitive to the production of DSBs after TLC388-radiation combined treatment and the formation of DSBs is strongly suggested to lead to the induction of apoptosis at doses lower than 4 Gy and to some necrosis at doses of 4 Gy or above. TLC388 enhances the production of DSBs and inhibits their repair, which contributes to the elucidation of the mechanisms of chemoradiosensitization of TLC388 and its development as a novel chemoradiosensitizing drug for improved radiotherapy.

Gamma-H2AX - a novel biomarker for DNA double-strand breaks.

When DNA damage, whether it is endogenous or exogenous, forms double stranded breaks (DSBs), it is always followed by the phosphorylation of the histone, H2AX. H2AX is a variant of the H2A protein family, which is a component of the histone octomer in nucleosomes. It is phosphorylated by kinases such as ataxia telangiectasia mutated (ATM) and ATM-Rad3-related (ATR) in the PI3K pathway. This newly phosphorylated protein, gamma-H2AX, is the first step in recruiting and localizing DNA repair proteins. DSBs can be induced by mechanisms such as ionizing radiation or cytotoxic agents and subsequently, gamma-H2AX foci quickly form. These foci represent the DSBs in a 1:1 manner and can be used as a biomarker for damage. An antibody can be raised against gamma-H2AX which can therefore be visualized by immunofluorescence through secondary antibodies. The detection and visualization of gamma-H2AX by flow cytometry allow the assessment of DNA damage, related DNA damage proteins and DNA repair. Gamma-H2AX also has other applications in the detection of genomic damage caused by cytotoxic chemical agents and environmental and physical damage, especially in the context of cancer treatment and therapy.