Potent Mechanism Of Action Research Articles

Cbx4 governs HIF-1α to involve in Th9 cell differentiation promoting asthma by its SUMO E3 ligase activity

The potential role of polycomb chromobox 4 (Cbx4), as a small ubiquitin-like ligase (SUMO) E3 ligase, in the development and exacerbation of asthma remains unclear. Hypoxia inducible factor-1 (HIF-1) is a key transcription factor in the cellular response to hypoxia and contributes to the pathogenesis and progression of a range of diseases, including asthma. Here, we aimed to investigate the interaction of Cbx4 with Hypoxia inducible factor-1α (HIF-1α) and the potent mechanism of action in asthma progression. In present study, in vitro and ex vivo results demonstrated that Cbx4 interacts with HIF-1α protein through its SUMO E3 ligase activity and enhances the sumoylation, which increases HIF-1 transactivation through Cbx4 and promotes the differentiation of Th9 cells, then in turn promotes the process of asthma. Treatment of inhibitors targeting SUMO E3 ligase activity of Cbx4 or HIF-1α can effectively reduce HIF-1α activation and differentiation of Th9 cells, which further attenuates the asthma in mouse model. Current results collectively demonstrated Cbx4 can govern HIF-1α to involve in Th9 cell differentiation promoting asthma by its SUMO E3 ligase activity, providing a new direction for clinical treatment of asthma.

Retreatment with Polatuzumab Vedotin in Combination with Rituximab Increases Antitumor Activity Against Polatuzumab Vedotin-Resistant DLBCL Cells

Introduction. Polatuzumab vedotin (Pola) is a monoclonal antibody against B-cell antigen CD79b conjugated to monomethyl auristatin E (MMAE), and is approved in combination with bendamustine and rituximab (Rit) in relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL) in various countries. Moreover, in the POLARIX study, Pola-R-CHP (cyclophosphamide, doxorubicin, and prednisone) achieved a significantly improved progression-free survival compared to R-CHOP (CHP plus vincristine) in previously untreated DLBCL. The treatment landscape of DLBCL have continued to change dynamically in recent years with the development of various agents. Although the detailed mechanism of resistance to Pola is not clear, understanding it is important for the development of next-line treatment to follow Pola-containing therapy, including retreatment with Pola. To address this, we established the Pola-resistant cells using Pola-sensitive human DLBCL and assessed the combination efficacy of Pola with Rit, the key component in the treatment of DLBCL to determine the efficacy of retreatment with Pola. Methods. We established Pola-resistant DLBCL cells from STR-428 and SU-DHL-4 cells through long-term exposure to Pola. The cell cytotoxicity to Pola was assessed by WST-8 assay. The in vitro combination efficacy of Pola plus Rit was assessed by measuring the sensitivity to complement-dependent cytotoxicity (CDC), rituximab's potent mechanism of action. In CDC assays, calcein-AM stained tumor cells were incubated with or without Rit in the medium containing 15% normal human serum. After incubating for 4 hours at 37℃, the fluorescence intensity was measured. Expression levels of protein were determined by flow cytometry or immunoblotting. For in vivo experiments, Pola-resistant STR-428 cells were injected subcutaneously into C.B-17/Icr-scid/scidJcl mice. Human IgG, Pola, or Rit was administered intravenously on Day 1. Results. Pola-resistant cells established from SU-DHL-4 cells (SU-DHL-4-Pola-R) showed a 2.3-fold higher IC50 value than parental cells. In SU-DHL-4-Pola-R cells, there was an increase in the expression of MDR1 (1.8-fold), a multidrug resistance pump mediating intracellular MMAE efflux. Interestingly, treatment with 1 μg/mL of Pola for 7 days further increased the IC50 value (16.8-fold) and the expression of MDR1 (3.6-fold）in SU-DHL-4-Pola-R cells.MDR1 inhibitor verapamil increased sensitivity to Pola, indicating that overexpression of MDR1 is one of the mechanisms of resistance to Pola in these cells. We then investigated the efficacy of combination therapy with Rit against Pola-resistant cells. Pretreatment with Pola or anti-CD79b antibody before the assays enhanced Rit-induced amount of membrane attack complex during complement activation and significantly increased CDC sensitivity in SU-DHL-4-Pola-R cells. Other Pola-resistant cells derived from STR-428 cells (STR-428-Pola-R) displayed an IC50 value 17.6-fold higher than the parental cells. STR-428-Pola-R cells did not exhibit Pola-resistant factors such as MDR1 upregulation or loss of CD79b expression, but showed decreased expression of Bim, an apoptosis-inducing factor. Stable knockdown of Bim reduced the sensitivity to Pola in parental STR-428 cells, indicating decreased Bim expression could be the resistant mechanism to Pola in these cells. In STR-428-Pola-R cells, 3 days pretreatment with Pola or MMAE significantly increased Rit-induced CDC sensitivity. Immunoblotting analysis revealed that pretreatment with Pola or MMAE downregulated the expression of Mcl-1, which is known to attenuate CDC sensitivity. Mcl-1 inhibitor AZD5991 significantly increased CDC sensitivity, suggesting that Pola-mediated downregulation of Mcl-1 could upregulate the sensitivity to CDC in these cells. In addition, treatment with Pola (1 mg/kg) plus Rit (10 mg/kg) significantly enhanced antitumor activity in mouse xenograft models derived from STR-428-Pola-R cells. Conclusion. Pretreatment with Pola enhanced Rit-induced CDC sensitivity in two Pola-resistant cells with distinct mechanisms of resistance: increased MDR1 or decreased Bim expression. Combination treatment of Pola with Rit enhanced antitumor activity in STR-428-Pola-R xenografted mice. These results indicate that retreatment with Pola in combination with Rit could be a therapeutic option in patients with Pola-resistant tumors.

Treatment of anticancer drugs in a real wastewater effluent using nanofiltration: A pilot scale study

Although anticancer drugs occur in the aquatic environment at trace concentration levels, these drugs might be of environmental concern due to their potent mechanism of action. Hence, new treatment technologies should be explored and, if necessary, conventional wastewater treatment plants (WWTPs) should be upgraded to avoid the release of these drugs into the aquatic environment.The effectiveness of nanofiltration to remove six anticancer drugs from wastewater effluents was assessed by installing a pilot unit with a Desal 5DK membrane at a domestic WWTP. Of the target anticancer drugs, only capecitabine, cyclophosphamide and ifosfamide were detected on the feed samples and thus, the removal efficiency was only evaluated for these drugs. Several 4-hour assays were conducted to explore the conditions that would maximize the rejection of the detected compounds and minimize fouling. Rejections higher than 96% were obtained in all the experiments for the detected compounds, independently of the operating conditions tested. Working under a controlled transmembrane pressure of 6 bar and recovery rate of 73% minimized fouling. A 24-hour assay was then conducted under these conditions and a minimal decay on permeability was observed. Samples were collected over time and rejections higher than 94% were obtained for all the detected drugs. None of the samples induced a significant immobilization effect in Daphnia Magna after 48 h of exposure.

Predicted concentrations of anticancer drugs in the aquatic environment: What should we monitor and where should we treat?

Anticancer drugs have been detected in the aquatic environment, they have a potent mechanism of action and their consumption is expected to drastically increase in the future. Consequently, it is crucial to routinely monitor the occurrence of anticancer drugs and to develop effective treatment options to avoid their release into the environment.Prior to implementing a monitoring program, it is important to define which anticancer drugs are more prone to be found in the surface waters. In this study the consumption of anticancer drugs in the Lisbon region (Portugal), Belgium and Haryana state (India) were used to estimate the concentrations that can be expected in surface waters.Moreover, one important aspect is to define the major entry route of anticancer drugs in the aquatic environment: is it hospital or household effluents? The results disclosed in this study showed that in Belgium and Lisbon, 94 % of the total amount of anticancer drugs were delivered to outpatients, indicating that household effluents are the primary input source of these drugs and thus, upgrading the treatment in the domestic wastewater facilities should be the focus.

Toxic effects of cisplatin cytostatic drug in mussel Mytilus galloprovincialis

Antineoplastic drugs used in chemotherapy were detected in aquatic environment: despite the very low concentrations (ng L−1 to ug L−1), due to their potent mechanism of action they could have adverse effects on non-target aquatic organisms particularly under chronic exposure. Cisplatin (CDDP) is one of the most effective anticancer drug currently in use but information on its ecotoxicological effects is very limited. In this study, Mytilus galloprovincialis was used to investigate the toxic effects related to CDDP exposure. Mussels were exposed to cisplatin (100 ng L−1) for 14 days: antioxidant (superoxide dismutase, catalase, total and selenium-dependent glutathione peroxidase) and phase II (glutathione-S-transferase) enzymes activities, oxidative damage (lipid peroxidation), genotoxicity (DNA damage) and neurotoxicity (acetylcholinesterase) was evaluated. Results indicate that CDDP at tested concentration induce changes in the antioxidant capacity, oxidative stress in target organs (digestive gland and gills) as well as DNA damage in mussel hemocytes and neurotoxicity representing a risk for non-target organisms.

Abstract S1-07: HER2 T cell dependent bispecific antibody (HER2-TDB) for treatment of HER2 positive breast cancer

Abstract Based on recent clinical success of tumor immunotherapies that block immune suppressive mechanisms to restore T cell function, there is a profound interest in the clinical development of T cell targeted therapies. We have produced a trastuzumab-based HER2 T cell dependent bispecific antibody (HER2-TDB) that conditionally activates T cells resulting in lysis of HER2 expressing cancer cells at low picomolar concentrations. Due to its unique mechanism of action, which is unrelated to HER2 signaling or sensitivity to chemotherapeutic agents, HER2-TDB can eliminate cells refractory to currently approved HER2 therapies. The potent anti-tumor activity of HER2-TDB was demonstrated using four model systems including MMTV-huHER2 and huCD3 transgenic mice. We demonstrate inhibitory effect of PD-L1 expression on the activity of bispecific T cell recruiting antibodies. This resistance mechanism is reversed by anti-PD-L1 treatment and combination of HER2-TDB with anti-PD-L1 immune therapy resulted in enhanced inhibition of tumor growth, increased response rates and durable responses. Significance: This report presents a new immunotherapy for HER2+ breast cancer with an alternative, extremely potent mechanism of action that is effective in cells resistant to current HER2 targeted therapies. Several significant advances are provided to bispecific T cell recruiting antibodies: we characterize a critical resistance mechanism, a potential diagnostic marker, a novel transgenic efficacy model and significantly improve the drug-like properties by using technology based on full length antibodies with natural architecture. Finally we demonstrate the benefit of combining two immune therapies: direct polyclonal recruitment of T cell activity together with inhibiting the T cell suppressive PD-1/PD-L1 signaling results in enhanced and durable long term responses. Citation Format: Teemu T Junttila, Ji Li, Jennifer Johnston, Maria Hristopoulos, Robyn Clark, Diego Ellerman, Bu-Er Wang, Yijin Li, Mary Mathieu, Guangmin Li, Judy Young, Elizabeth Luis, Gail Lewis Phillips, Eric Stefanich, Cristoph Spiess, Andrew Polson, Bryan Irving, Justin M Scheer, Melissa R Junttila, Mark S Dennis, Robert Kelley, Klara Totpal, Allen Ebens. HER2 T cell dependent bispecific antibody (HER2-TDB) for treatment of HER2 positive breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S1-07.

S4-04-05: Dimebon: A phase 3 investigational agent for Alzheimer's disease with a novel mitochondrial mechanism of action

Dimebon is an investigational oral small molecule currently in Phase 3 development for the treatment of Alzheimer's disease (AD). Dimebon is hypothesized to stabilize and enhance mitochondrial and neuronal function. Patients with mild-to-moderate AD treated with Dimebon for one year were stabilized on measures of cognition and memory, activities of daily living, behavior and global function, while placebo-treated patients declined significantly. The magnitude and durability of clinical benefits and excellent safety and tolerability profile observed for Dimebon in Alzheimer's patients suggests a mechanism of action (MOA) distinct from currently marketed AD drugs. Preclinical experiments confirm Dimebon's lack of significant activity against cholinesterases and NMDA receptors, consistent with its unique MOA. Similarly, Dimebon does not appear to interact with other targets implicated in cognition and memory, including the muscarinic receptors, nicotinic receptors and phosphodiesterases. Neurodegenerative diseases such as AD are characterized by synapse loss and neuron death. A body of literature suggests that abnormal depolarization of mitochondrial membranes plays a significant role in the loss of neuron function in several neurodegenerative diseases, including AD. Dimebon is a highly potent (pM to low nM) stabilizer of mitochondria as measured by JC-1 staining of primary neurons in culture. Dimebon is also a potent (pM to low nM) stimulator of neurite outgrowth in primary neurons derived from the cortex, hippocampus and spinal cord of rodents. Dimebon's neurotrophic effects are believed to be related to its ability to stabilize, protect and enhance mitochondrial and neuronal function. Dimebon's efficacy in animal models of memory impairment at picomolar plasma concentrations is consistent with a potent MOA. Neuroprotection measured by mitochondrial vital stains occurs within minutes to hours of Dimebon exposure, while the trophic effects on neurite outgrowth occur over longer exposures. These activities may be related to the short term and longer term effects of Dimebon seen in the completed pivotal Dimebon AD trial. Dimebon is a promising potential therapeutic agent for AD, with a unique and novel target, the mitochondria. The most potent activity of Dimebon identified to date is the stabilization and enhancement of mitochondrial and neuronal function.

S4-04-06: Presenilin complex modulation of APP and notch molecule at gammma and epsilon sites

and neuronal function. Patients with mild-to-moderate AD treated with Dimebon for one year were stabilized on measures of cognition and memory, activities of daily living, behavior and global function, while placebo-treated patients declined significantly. The magnitude and durability of clinical benefits and excellent safety and tolerability profile observed for Dimebon in Alzheimer’s patients suggests a mechanism of action (MOA) distinct from currently marketed AD drugs. Preclinical experiments confirm Dimebon’s lack of significant activity against cholinesterases and NMDA receptors, consistent with its unique MOA. Similarly, Dimebon does not appear to interact with other targets implicated in cognition and memory, including the muscarinic receptors, nicotinic receptors and phosphodiesterases. Neurodegenerative diseases such as AD are characterized by synapse loss and neuron death. A body of literature suggests that abnormal depolarization of mitochondrial membranes plays a significant role in the loss of neuron function in several neurodegenerative diseases, including AD. Results: Dimebon is a highly potent (pM to low nM) stabilizer of mitochondria as measured by JC-1 staining of primary neurons in culture. Dimebon is also a potent (pM to low nM) stimulator of neurite outgrowth in primary neurons derived from the cortex, hippocampus and spinal cord of rodents. Dimebon’s neurotrophic effects are believed to be related to its ability to stabilize, protect and enhance mitochondrial and neuronal function. Dimebon’s efficacy in animal models of memory impairment at picomolar plasma concentrations is consistent with a potent MOA. Neuroprotection measured by mitochondrial vital stains occurs within minutes to hours of Dimebon exposure, while the trophic effects on neurite outgrowth occur over longer exposures. These activities may be related to the short term and longer term effects of Dimebon seen in the completed pivotal Dimebon AD trial. Conclusions: Dimebon is a promising potential therapeutic agent for AD, with a unique and novel target, the mitochondria. The most potent activity of Dimebon identified to date is the stabilization and enhancement of mitochondrial and neuronal function.

Hydroxyurea: new insights on an old drug

Anticancer drugs have been detected in the aquatic environment, they have a potent mechanism of action and their consumption is expected to drastically increase in the future. Consequently, it is crucial to routinely monitor the occurrence of anticancer drugs and to develop effective treatment options to avoid their release into the environment.Prior to implementing a monitoring program, it is important to define which anticancer drugs are more prone to be found in the surface waters. In this study the consumption of anticancer drugs in the Lisbon region (Portugal), Belgium and Haryana state (India) were used to estimate the concentrations that can be expected in surface waters.Moreover, one important aspect is to define the major entry route of anticancer drugs in the aquatic environment: is it hospital or household effluents? The results disclosed in this study showed that in Belgium and Lisbon, 94 % of the total amount of anticancer drugs were delivered to outpatients, indicating that household effluents are the primary input source of these drugs and thus, upgrading the treatment in the domestic wastewater facilities should be the focus.