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Simple Summary: Antibody-directed enzyme prodrug therapy (ADEPT) is a promising alternative to conventional chemotherapy. The idea is to activate a prodrug into a cytotoxic agent at the tumor site with the aid of an enzyme that has been delivered to the tumor by a therapeutic antibody. Thereby offering reduced off-target toxicity and improved selectivity. Telcyta is a glutathione transferase pi-class (GST P1-1) activated prodrug. The human enzyme has modest activity with Telcyta, although being the most efficient enzyme known. The aim of this work was to molecularly redesign human GST P1-1 for enhanced activity with the prodrug Telcyta to achieve a higher therapeutic index for ADEPT. A single-point mutation improved the activity 2.9-fold over the wildtype value, albeit at the cost of thermal stability. Additional mutations restored stability to GST P1-1 with preserved elevated activity. Our findings represent a first step towards a functional ADEPT application for Telcyta. Protein engineering can be used to tailor enzymes for medical purposes, including antibody-directed enzyme prodrug therapy (ADEPT), which can act as a tumor-targeted alternative to conventional chemotherapy for cancer. In ADEPT, the antibody serves as a vector, delivering a drug-activating enzyme selectively to the tumor site. Glutathione transferases (GSTs) are a family of naturally occurring detoxication enzymes, and the finding that some of them are overexpressed in tumors has been exploited to develop GST-activated prodrugs. The prodrug Telcyta is activated by GST P1-1, which is the GST most commonly elevated in cancer cells, implying that tumors overexpressing GST P1-1 should be particularly vulnerable to Telcyta. Promising antitumor activity has been noted in clinical trials, but the wildtype enzyme has modest activity with Telcyta, and further functional improvement would enhance its usefulness for ADEPT. We utilized protein engineering to construct human GST P1-1 gene variants in the search for enzymes with enhanced activity with Telcyta. The variant Y109H displayed a 2.9-fold higher enzyme activity compared to the wild-type GST P1-1. However, increased catalytic potency was accompanied by decreased thermal stability of the Y109H enzyme, losing 99% of its activity in 8 min at 50 °C. Thermal stability was restored by four additional mutations simultaneously introduced without loss of the enhanced activity with Telcyta. The mutation Q85R was identified as an important contributor to the regained thermostability. These results represent a first step towards a functional ADEPT application for Telcyta. [ABSTRACT FROM AUTHOR]

• An advanced dementia prognostic tool (ADEPT) was used to predict 2-year survival. • Patients had higher mean ADEPT scores but lower mortality. • ADEPT cutoff score 11.2 has diagnostic reference value for survival prediction. • There was no difference in survival prediction between hospitals and nursing homes. • Filial piety and other factors generate positive treatment attitude. In this prospective study, we evaluated the usefulness of the advanced dementia prognostic tool (ADEPT) for estimating the 2-year survival of persons with advanced dementia (AD) in China. The study predicted the 2-year mortality of 115 persons with AD using the ADEPT score. In total, 115 persons with AD were included in the study. Of these persons, 48 died. The mean ADEPT score was 13.0. The AUROC for the prediction of the 2-year mortality rate using the ADEPT score was 0.62. The optimal threshold of the ADEPT score was 11.2, which had an AUROC of 0.63, specificity of 41.8, and sensitivity of 83.3. The ADEPT score based on a threshold of 11.2 may serve as a prognostic tool to determine the 2-year survival rate of persons with AD in Chongqing, China. However, further studies are needed to explore the nature of this relationship. [ABSTRACT FROM AUTHOR]

Background: Current primary care cognitive assessment tools are either crude or time-consuming instruments that can only detect cognitive impairment when it is well established. This leads to unnecessary or late referrals to memory services, by which time the disease may have already progressed into more severe stages. Due to the COVID-19 pandemic, some memory services have adapted to the new environment by shifting to remote assessments of patients to meet service user demand. However, the use of remote cognitive assessments has been inconsistent, and there has been little evaluation of the outcome of such a change in clinical practice. Emerging research has highlighted computerized cognitive tests, such as the Integrated Cognitive Assessment (ICA), as the leading candidates for adoption in clinical practice. This is true both during the pandemic and in the post-COVID-19 era as part of healthcare innovation. Objectives: The Accelerating Dementias Pathways Technologies (ADePT) Study was initiated in order to address this challenge and develop a real-world evidence basis to support the adoption of ICA as an inexpensive screening tool for the detection of cognitive impairment and improving the efficiency of the dementia care pathway. Methods: Ninety-nine patients aged 55-90 who have been referred to a memory clinic by a general practitioner (GP) were recruited. Participants completed the ICA either at home or in the clinic along with medical history and usability questionnaires. The GP referral and ICA outcome were compared with the specialist diagnosis obtained at the memory clinic. Participants were given the option to carry out a retest visit where they were again given the chance to take the ICA test either remotely or face-to-face. Results: The primary outcome of the study compared GP referral with specialist diagnosis of mild cognitive impairment (MCI) and dementia. Of those the GP referred to memory clinics, 78% were necessary referrals, with ~22% unnecessary referrals, or patients who should have been referred to other services as they had disorders other than MCI/dementia. In the same population the ICA was able to correctly identify cognitive impairment in ~90% of patients, with approximately 9% of patients being false negatives. From the subset of unnecessary GP referrals, the ICA classified ~72% of those as not having cognitive impairment, suggesting that these unnecessary referrals may not have been made if the ICA was in use. ICA demonstrated a sensitivity of 93% for dementia and 83% for MCI, with a specificity of 80% for both conditions in detecting cognitive impairment. Additionally, the test-retest prediction agreement for the ICA was 87.5%. Conclusion: The results from this study demonstrate the potential of the ICA as a screening tool, which can be used to support accurate referrals from primary care settings, along with the work conducted in memory clinics and in secondary care. The ICA's sensitivity and specificity in detecting cognitive impairment in MCI surpassed the overall standard of care reported in existing literature. [ABSTRACT FROM AUTHOR]

A thermal alkali pre‐treatment anaerobic digestion elutriated phased treatment (T‐ADEPT) was developed by combining the thermal‐alkali pre‐treatment (TAP) with the anaerobic digestion elutriated phased treatment (ADEPT) for the anaerobic co‐digestion of food waste (FW) and dewatered sewage sludge (SS). To improve the solubilization efficiency and methane yield, the optimal conditions for the TAP and ADEPT processes were identified. The soluble chemical oxygen demand (SCOD) solubilization, volatile suspended solids (VSS) reduction rate, volatile fatty acid (VFA) concentration, and methane yield all improved with our proposed process. The variations of the physical properties of the FW and SS mixtures confirm that the TAP process enhances the solubilization of organic matter. The methane yield of the T‐ADEPT process was 0.368 L CH4/g VSadded, which was approximately 1.4 and 1.2 times higher than the values for a conventional two‐stage anaerobic digestion (AD) process and an AD process with pre‐treatment, respectively. These results show that the application of TAP and ADEPT processes using granular sludge can be an effective approach for the anaerobic co‐digestion of FW and SS. The proposed technique is more tolerant of the inhibitory effects of high concentrations of toxic compounds compared with a conventional two‐stage AD system. Modifying a conventional anaerobic digester has the potential to deliver low hydraulic retention times (HRTs) and high organic loading rates (OLRs). © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Aims: To establish the survivorship, function, and metal ion levels in an unselected series of metal-on-metal hip resurfacing arthroplasties (HRAs) performed by a non-designer surgeon. Methods: We reviewed 105 consecutive HRAs in 83 patients, performed by a single surgeon, at a mean follow-up of 14.9 years (9.3 to 19.1). The cohort included 45 male and 38 female patients, with a mean age of 49.5 years (SD 12.5) Results: At the time of review 13 patients with 15 hips had died from causes unrelated to the hip operation, and 14 hips had undergone revision surgery, giving an overall survival rate of rate of 86.7% (95% confidence interval (CI) 84.2 to 89.1). The survival rate in men was 97.7% (95% CI 96.3 to 98.9) and in women was 73.4% (95% CI 70.6 to 75.1). The median head size of the failed group was 42 mm (interquartile range (IQR) 42 to 44), and in the surviving group was 50 mm (IQR 46 to 50). In all, 13 of the 14 revised hips had a femoral component measuring ≤ 46 mm. The mean blood levels of cobalt and chromium ions were 26.6 nmol/l (SD 24.5) and 30.6 nmol/l (SD 15.3), respectively. No metal ion levels exceeded the safe limit. The mean Oxford Hip Score was 41.5 (SD 8.9) and Harris Hip Score was 89.9 (14.8). In the surviving group, four patients had radiolucent lines around the stem of the femoral component, and one had lysis around the acetabular component; eight hips demonstrated heterotopic ossification. Conclusion: Our results confirm the existing understanding that HRA provides good long-term survival and function in patients with adequate-sized femoral heads. This is evidenced by a 97.7% survival rate among men (larger heads) in our series at a mean follow-up of 14.9 years. Failure is closely related to head sizes ≤ 46 cm. Cite this article: Bone Jt Open 2022;3(1):68–76.

Antibody-enzyme conjugates have shown potential as tissue-specific prodrug activators by antibody-directed enzyme prodrug therapy (ADEPT), but the approach met challenges clinically due to systemic drug release. Here, we report a novel dual-targeting ADEPT system (DuADEPT) which is based on active cancer receptor targeting of both a trastuzumab-sialidase conjugate (Tz-Sia) and a highly potent sialidase-activated monomethyl auristatin E (MMAE) prodrug scaffold. The scaffold is based on a four-way junction of the artificial nucleic acid analog acyclic (L)-threoninol nucleic acid ((L)-aTNA) which at the ends of its four arms carries one nanobody targeting HER2 and three copies of the prodrug. Dual-targeting of the constructs to two proximal epitopes of HER2 was shown by flow cytometry, and a dual-targeted enzymatic drug release assay revealed cytotoxicity upon prodrug activation specifically for HER2-positive cancer cells. The specific delivery and activation of prodrugs in this way could potentially be used to decrease systemic side effects and increase drug efficacy, and utilization of Tz-Sia provides an opportunity to combine the local chemotherapeutic effect of the DuADEPT with an anticancer immune response., (© 2024 The Authors. ChemBioChem published by Wiley-VCH GmbH.)

Cytosine deaminase (CDA) is a non-mammalian enzyme with powerful activity in mediating the prodrug 5-fluorcytosine (5-FC) into toxic drug 5-fluorouracil (5-FU), as an alternative directed approach for the traditional chemotherapies and radiotherapies of cancer. This enzyme has been frequently reported and characterized from various microorganisms. The therapeutic strategy of 5-FC-CDA involves the administration of CDA followed by the prodrug 5-FC injection to generate cytotoxic 5-FU. The antiproliferative activity of CDA-5-FC elaborates from the higher activity of uracil pathway in tumor cells than normal ones. The main challenge of the therapeutic drug 5-FU are the short half-life, lack of selectivity and emergence of the drug resistance, consistently to the other chemotherapies. So, mediating the 5-FU to the tumor cells by CDA is one of the most feasible approaches to direct the drug to the tumor cells, reducing its toxic effects and improving their pharmacokinetic properties. Nevertheless, the catalytic efficiency, stability, antigenicity and targetability of CDA-5-FC, are the major challenges that limit the clinical application of this approach. Thus, exploring the biochemical properties of CDA from various microorganisms, as well as the approaches for localizing the system of CDA-5-FC to the tumor cells via the antibody directed enzyme prodrug therapy (ADEPT) and gene directed prodrug therapy (GDEPT) were the objectives of this review. Finally, the perspectives for increasing the therapeutic efficacy, and targetability of the CDA-5-FC system were described.

The paper briefly presents the dynamic synthesis of mechanisms with superior couplings, force, and speed distribution, efficiency, loss coefficient, dynamic coefficient or motion transmission function, determination of variable angular input speed from the crank or cam based on solving the equation Lagrange, the determination of the dynamic variation of the follower (adept) based on the integration of Newton's equation, and the dynamic analysis of several models taken into account. In the end, the original relations for calculating the efficiency of a gear are presented. [ABSTRACT FROM AUTHOR]

Quantifying gait parameters and ambulatory monitoring of changes in these parameters have become increasingly important in epidemiological and clinical studies. Using high-density accelerometry measurements, we propose adaptive empirical pattern transformation (ADEPT), a fast, scalable, and accurate method for segmentation of individual walking strides. ADEPT computes the covariance between a scaled and translated pattern function and the data, an idea similar to the continuous wavelet transform. The difference is that ADEPT uses a data-based pattern function, allows multiple pattern functions, can use other distances instead of the covariance, and the pattern function is not required to satisfy the wavelet admissibility condition. Compared to many existing approaches, ADEPT is designed to work with data collected at various body locations and is invariant to the direction of accelerometer axes relative to body orientation. The method is applied to and validated on accelerometry data collected during a $450$-m outdoor walk of $32$ study participants wearing accelerometers on the wrist, hip, and both ankles. Additionally, all scripts and data needed to reproduce presented results are included in supplementary material available at Biostatistics online. [ABSTRACT FROM AUTHOR]

Cancer is the dangerous disease which caused millions of deaths in worldwide. Enzyme prodrug therapy uses enzymes artificially introduced into the body to convert pro-drugs which have poor biological activity to the active form in the desired location within the body. The use of enzyme pro-drug therapy has gained attention as it has the ability to improve the efficacy and safety of cancer treatment. Chemotherapy for cancer patients has limited success including some drawbacks like systemic toxicity, insufficient drug concentration in tumors. To overcome these drawbacks and improve the cancer treatment the enzyme pro-drug therapy is selected. Enzyme prodrug therapy uses enzymes artificially introduced into the body to convert pro-drugs which have poor biological activity to the active form in the desired location within the body. The selective activation of pro-drugs in tumor tissues by exogenous enzymes for cancer therapy was accomplished by several ways including gene-directed enzyme pro-drug therapy(GDEPT), virus-directed enzyme pro-drug therapy(VDEPT), antibody-directed enzyme pro-drug therapy(ADEPT). Most of these therapies are based on antibody dependent cellular cyto-toxicity, targeted delivery of cytotoxic drugs/tumor site specific activation of prodrugs. This review aims at providing an overview regarding four major systems of GDEPT, ADEPT, VDEPT. Later this review focuses on the bystander effect and combination therapy associated with gene therapy. [ABSTRACT FROM AUTHOR]

Background: Until recently, patients who have the same type and stage of cancer all receive the same treatment. It has been established, however, that individuals with the same disease respond differently to the same therapy. Further, each tumor undergoes genetic changes that cause cancer to grow and metastasize. The changes that occur in one person’s cancer may not occur in others with the same cancer type. These differences also lead to different responses to treatment.Precision medicine, also known as personalized medicine, is a strategy that allows the selection of a treatment based on the patient’s genetic makeup. In the case of cancer, the treatment is tailored to take into account the genetic changes that may occur in an individual’s tumor. Precision medicine, therefore, could be defined in terms of the targets involved in targeted therapy. Methods: A literature search in electronic data bases using keywords “cancer targeted therapy, personalized medicine and cancer combination therapies” was conducted to include papers from 2010 to June 2019. Results: Recent developments in strategies of targeted cancer therapy were reported. Specifically, on the two types of targeted therapy; first, immune-based therapy such as the use of immune checkpoint inhibitors (ICIs), immune cytokines, tumor-targeted superantigens (TTS) and ligand targeted therapeutics (LTTs). The second strategy deals with enzyme/small molecules-based therapies, such as the use of a proteolysis targeting chimera (PROTAC), antibody-drug conjugates (ADC) and antibody-directed enzyme prodrug therapy (ADEPT). The precise targeting of the drug to the gene or protein under attack was also investigated, in other words, how precision medicine can be used to tailor treatments. Conclusion: The conventional therapeutic paradigm for cancer and other diseases has focused on a single type of intervention for all patients. However, a large literature in oncology supports the therapeutic benefits of a precision medicine approach to therapy as well as combination therapies.

The paper briefly presents the dynamic synthesis of mechanisms with superior couplings, force, and speed distribution, efficiency, loss coefficient, dynamic coefficient or motion transmission function, determination of variable angular input speed from the crank or cam based on solving the equation Lagrange, the determination of the dynamic variation of the follower (adept) based on the integration of Newton’s equation, and the dynamic analysis of several models taken into account. In the end, the original relations for calculating the efficiency of a gear are presented.

We have previously constructed an antibody-avidin (Av) fusion protein, anti-transferrin receptor (TfR) IgG3-Av, which can deliver biotinylated molecules to cells expressing the TfR. We now describe the use of the fusion protein for antibody-directed enzyme prodrug therapy (ADEPT). The 67 amino acid carboxyl-terminal domain (P67) of human propionyl-CoA carboxylase a subunit can be metabolically biotinylated at a fixed lysine residue. We genetically fused P67 to the carboxyl terminus of the yeast enzyme FCU1, a derivative of cytosine deaminase that can convert the non-toxic prodrug 5-fluorocytosine to the cytotoxic agent 5-fluorouracil. When produced in Escherichia coli cells overexpressing a biotin protein ligase, the FCU1-P67 fusion protein was efficiently mono-biotinylated. In the presence of 5-fluorocytosine, the biotinylated fusion protein conjugated to anti-rat TfR IgG3-Av efficiently killed rat Y3-Ag1.2.3 myeloma cells in vitro, while the same protein conjugated to an irrelevant (anti-dansyl) antibody fused to Av showed no cytotoxic effect. Efficient tumor cell killing was also observed when E. coli purine nucleoside phosphorylase was similarly targeted to the tumor cells in the presence of the prodrug 2-fluoro-2'-deoxyadenosine. These results suggest that when combined with P67-based biotinylation, anti-TfR IgG3-Av could serve as a universal delivery vector for targeted chemotherapy of cancer. (c) 2004 Elsevier B.V. All rights reserved.

Modern industrial robotic systems are highly interconnected. They operate in a distributed environment and communicate with sensors, computer vision systems, mechatronic devices, and computational components. On the fundamental level, communication and coordination between all parties in such distributed system are characterized by discrete event behavior. The latter is largely attributed to the specifics of communication over the network, which, in terms, facilitates asynchronous programming and explicit event handling. In addition, on the conceptual level, events are an important building block for realizing reactivity and coordination. Event-driven architecture has manifested its effectiveness for building loosely-coupled systems based on publish-subscribe middleware, either general-purpose or robotic-oriented. Despite all the advances in middleware, industrial robots remain difficult to program in context of distributed systems, to a large extent due to the limitation of the native robot platforms. This paper proposes an architecture for flexible event-based control of industrial robots based on the Adept V+ platform. The architecture is based on the robot controller providing a TCP/IP server and a collection of robot skills, and a high-level control module deployed to a dedicated computing device. The control module possesses bidirectional communication with the robot controller and publish/subscribe messaging with external systems. It is programmed in asynchronous style using pyadept, a Python library based on Python coroutines, AsyncIO event loop and ZeroMQ middleware. The proposed solution facilitates integration of Adept robots into distributed environments and building more flexible robotic solutions with event-based logic.

Glucarpidase, also known as carboxypeptidase G2, is a Food and Drug Administration-approved enzyme used in targeted cancer strategies such as antibody-directed enzyme prodrug therapy (ADEPT). It is also used in drug detoxification when cancer patients have excessive levels of the anti-cancer agent methotrexate. The application of glucarpidase is limited by its potential immunogenicity and limited catalytic efficiency. To overcome these pitfalls, mutagenesis was applied to the glucarpidase gene of Pseudomonas sp. strain RS-16 to isolate three novels “biobetter” variants with higher specific enzyme activity. DNA sequence analysis of the genes for the variants showed that each had a single point mutation, resulting in the amino acid substitutions: I100 T, G123S and T239 A. Km, Vmax and Kcat measurements confirmed that each variant had increased catalytic efficiency relative to wild type glucarpidase.Additionally, circular dichroism studies indicated that they had a higher alpha-helical content relative to the wild type enzyme. However, three different software packages predicted that they had reduced protein stability, which is consistent with having higher activities as a tradeoff. The novel glucarpidase variants presented in this work could pave the way for more efficient drug detoxification and might allow dose escalation during chemotherapy. They also have the potential to increase the efficiency of ADEPT and to reduce the number of treatment cycles, thereby reducing the risk that patients will develop antibodies to glucarpidase.

Objectives To evaluate the relationship between radiographic progression and disease activity in subjects with PsA treated with adalimumab (ADA) or placebo (PBO) and the impact of concomitant MTX. Methods This was a post hoc analysis of the randomized, double-blind, PBO-controlled ADEPT trial. Subjects were categorized according to time-averaged (TA) disease activity (remission, low, moderate or high) based on Disease Activity Score of 28 joints with CRP [DAS28(CRP)], Disease Activity Index for Psoriatic Arthritis (DAPSA) or Psoriatic Arthritis Disease Activity Score (PASDAS), and achievement of minimal disease activity (MDA) at week 24. Radiographic progression was assessed as change in modified total Sharp score (ΔmTSS) from baseline to week 24. The analyses included interaction terms between disease activity and treatment on radiographic progression, comparison of radiographic progression in subjects categorized by disease activity and treatment, and correlation between disease activity and radiographic progression by treatment. Results The interaction terms for TA disease activity and treatment on ΔmTSS were significant (P = 0.002–0.008). Irrespective of concomitant MTX, ΔmTSS was lower with ADA vs PBO in all disease activity categories. Importantly, even in subjects having moderate or high disease activity or not achieving MDA, ΔmTSS was significantly lower on ADA than PBO (P = 0.05–0.001 for TA-DAPSA, TA-PASDAS and MDA). Correlations between TA disease activity scores and ΔmTSS were moderately positive and significant (P < 0.001) with PBO but non-significant with ADA. Conclusion Among subjects with PsA treated with ADA, there was evidence of a 'disconnect' between disease activity and radiographic progression: inhibition of radiographic progression was greater than expected based on control of clinical disease activity alone. MTX had no added effect. Trial registration ClinicalTrials.gov, http://clinicaltrials.gov, NCT00646386. [ABSTRACT FROM AUTHOR]

Introduction: Prodrugs have been used to improve the selectivity and efficacy of cancer therapy by targeting unique abnormal markers that are overexpressed by cancer cells and are absent in normal tissues. In this context, different strategies have been exploited and new ones are being developed each year. Areas covered: In this review, an integrated view of the potential use of prodrugs in targeted cancer therapy is provided. Passive and active strategies are discussed in light of the advantages of each one and some successful examples are provided, as well as the clinical status of several prodrugs. Among them, antibody-drug conjugates (ADCs) are the most commonly used. However, several drawbacks, including limited prodrug uptake, poor pharmacokinetics, immunogenicity problems, difficulties in selective targeting and gene expression, and optimized bystander effects limit their clinical applications. Expert opinion: Despite the efforts of different companies and research groups, several drawbacks, such as the lack of relevant in vivo models, complexity of the human metabolism, and economic limitations, have hampered the development of new prodrugs for targeted cancer therapy. As a result, we believe that the combination of prodrugs with cancer nanotechnology and other newly developed approaches, such as aptamer-conjugated nanomaterials, are efficient strategies. [ABSTRACT FROM AUTHOR]

Abstract Recombinant glucarpidase (formerly: Carboxypeptidase G2, CPG2) is used in Antibody Directed Enzyme Prodrug Therapy (ADEPT) for the treatment of cancer. In common with many protein therapeutics, glucarpidase has a relatively short half-life in serum and, due to the need for the repeated cycles of the ADEPT, its bioavailability may be further diminished by neutralizing antibodies produced by patients. PEGylation and fusion with human serum albumin (HSA) are two approaches that are commonly employed to increase the residency time of protein therapeutics in blood, and also to increase the half-lives of the proteins in vivo. To address this stability and the immunogenicity problems, 'biobetter' glucarpidase variants, mono-PEGylated glucarpidase, and HSA fused glucarpidase by genetic fusion with albumin, were produced. Biochemical and bioactivity analyses, including anti-proliferation, bioassays, circular dichroism, and in vitro stability using human blood serum and immunoassays, demonstrated that the functional activities of the designed glucarpidase conjugates were maintained. The immunotoxicity studies indicated that the PEGylated glucarpidase did not significantly induce T-cell proliferation, suggesting that glucarpidase epitopes were masked by the PEG moiety. However, free glucarpidase and HSA-glucarpidase significantly increased T-cell proliferation compared with the negative control. In the latter case, this might be due to the type of expression system used or due to trace impurities associated with the highly purified (99.99%) recombinant HSA-glucarpidase. Both PEGylated glucarpidase and HAS-glucarpidase exhibit more stability in human serum and were more resistant to key human proteases relative to native glucarpidase. To our knowledge, this study is the first to report stable and less immunogenic glucarpidase variants produced by PEGylation and fusion with HSA. The results suggest that they may have better efficacy in drug detoxification and ADEPT, thereby improving this cancer treatment strategy. Graphical abstract Successful production of long acting, proteases resistant and less immunogenic glucarpidases for efficient cancer treatment. Unlabelled Image [ABSTRACT FROM AUTHOR]

Many cancer diseases, e.g., prostate cancer and lung cancer, develop very slowly. Common chemotherapeutics like vincristine, vinblastine and taxol target cancer cells in their proliferating states. In slowly developing cancer diseases only a minor part of the malignant cells will be in a proliferative state, and consequently these drugs will exert a concomitant damage on rapidly proliferating benign tissue as well. A number of toxins possess an ability to kill cells in all states independently of whether they are benign or malignant. Such toxins can only be used as chemotherapeutics if they can be targeted selectively against the tumors. Examples of such toxins are mertansine, calicheamicins and thapsigargins, which all kill cells at low micromolar or nanomolar concentrations. Advanced prodrug concepts enabling targeting of these toxins to cancer tissue comprise antibody-directed enzyme prodrug therapy (ADEPT), gene-directed enzyme prodrug therapy (GDEPT), lectin-directed enzyme-activated prodrug therapy (LEAPT), and antibody-drug conjugated therapy (ADC), which will be discussed in the present review. The review also includes recent examples of protease-targeting chimera (PROTAC) for knockdown of receptors essential for development of tumors. In addition, targeting of toxins relying on tumor-overexpressed enzymes with unique substrate specificity will be mentioned.

Abstract Escherichia coli β-lactamase TEM-1 is potentially useful in the antibody-directed enzyme/prodrug therapy (ADEPT), converting nontoxic prodrugs to toxic agents. The produced toxin would kill cancer cells, when the enzyme is attached to a tumor-antigen-specific antibody. However, the off-site reaction possibly occurring in the blood or normal tissues raises safety concern. In the present study, we engineered TEM-1 variants preferentially active at pH 5.8–6.2, near the pH of the acidic microenvironment of tumor. A library of randomly mutagenized variants was screened for the ability to confer an antibiotic resistance on E. coli cells in acidic growth media and not in neutral media, to isolate a variant with a Thr-to-Ile substitution at position 160. An extensive mutagenesis study was then conducted in the proximity of this position, to show that a Leu162Glu mutation also causes the acid preference. Kinetic analyses indicated that the overall activity of the wild-type TEM-1 hardly changes over a pH range from 5.8 to 7.0, whereas TEM-1(T160I) is 1.5-times as active at pH 6.2 than pH 7.0, and TEM-1(T160I) is 3.1-fold as active at pH 5.8 than pH 7.0. A further mutagenesis study suggested that a change in the overall structure of the enzyme underlies the pH dependency of the variants. Highlights • Genetic screening is useful for obtaining β-lactamases with altered pH dependency. • A few mutations each suppress the activity of a β-lactamase at pH 7.0. • The engineered β-lactamase variants are more active under the acidic conditions. • The relevant amino acid substitutions are located far from the catalytic site. [ABSTRACT FROM AUTHOR]

Cancer is considered as one of the most serious health problems today. The discovery of nitrogen mustard as an alkylating agent in 1942, opened a new era in the cancer chemotherapy. This valuable class of alkylating agent exerts its biological activity by binding to DNA, cross linking two strands, preventing DNA replication and ultimate cell death. At the molecular level, nitrogen lone pairs of nitrogen mustard generate a strained intermediate “aziridinium ion” which is very reactive towards DNA of tumor cell as well as normal cell resulting in various adverse side effects alogwith therapeutic implications. Over the last 75 years, due to its high reactivity and peripheral cytotoxicity, numerous modifications have been made in the area of nitrogen mustard to improve its efficacy as well as enhancing drug delivery specifically to tumor cells. This review mainly discusses the medicinal chemistry aspects in the development of various classes of nitrogen mustards (mechlorethamine, chlorambucil, melphalan, cyclophosphamide and steroidal based nitrogen mustards). The literature collection includes the historical and the latest developments in these areas. This comprehensive review also attempted to showcase the recent progress in the targeted delivery of nitrogen mustards that includes DNA directed nitrogen mustards, antibody directed enzyme prodrug therapy (ADEPT), gene directed enzyme prodrug therapy (GDEPT), nitrogen mustard activated by glutathione transferase, peptide based nitrogen mustards and CNS targeted nitrogen mustards. [ABSTRACT FROM AUTHOR]

Aspirin was used as the lead compound, and its structure was modified by galactosylation. Galactose-based aspirin prodrug was synthesized by using the α-d-glactopyranosyl bromide as glycosyl donor and aspirin as acceptor. The experimental method is simple and reproducible, has high yield and great practical value. The galactosylated aspirin prodrug was found to possess reduced cytotoxicity compared to aspirin, and selectively exhibited antiproliferative activity in the presence or in the absence of β-d-galactoside galactohydrolase with the approach of antibody-directed enzyme prodrug therapy (ADEPT) or the prodrug monotherapy (PMT). [ABSTRACT FROM AUTHOR]