To what extent may aminochrome increase the vulnerability of dopaminergic neurons in the context of Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disorder that progresses over time and is characterized by preferential reduction of dopaminergic neurons in the substantia nigra. Although the precise mechanisms leading to cell death in neurodegenerative disorders, such as PD, are not fully understood, it is widely accepted that increased oxidative stress may be a prevalent factor contributing to the deterioration of the nigrostriatal dopaminergic fibers in such conditions. Aminochrome, generated from dopamine (DA) metabolism, plays an important role in multiple pathogenic mechanisms associated with PD. Its capacity to induce a gradual reduction in dopaminergic neurons is due to its endogenous neurotoxicity. The formation of aminochrome results in the production of various reactive oxygen species (ROS), including pro-inflammatory factors, superoxide, nitric oxide, and hydroxyl radicals. This, in turn, causes loss of dopaminergic neurons, reducing DA uptake, and reduced numbers and shortened dendrites. Notably, o-quinones, which are more cytotoxic, arise from the oxidation of DA and possess a higher capacity to impede cellular defense mechanisms, thereby resulting in the death of neuronal cells. Aminochrome potentially contributes to the pathophysiology of PD by forming adducts with various proteins. All of the aforementioned effects suggest that aminochrome may play a crucial role in the pathophysiology of PD. Thus, aminochrome may serve as a more relevant preclinical model for PD, facilitating a better understanding of its pathophysiological processes and identification of novel therapeutic strategies aimed at preventing or slowing disease progression.

Current Clinical Trials in Non-muscle Invasive Bladder Cancer.

PURPOSE OF REVIEW: As our molecular understanding of bladder cancer continues to advance, more and more novel agents are entering clinical trials across the spectrum of bladder cancer stages. The clinical trial activity for non-muscle invasive bladder cancer (NMIBC) has been boosted further by the evolution of specific disease states that set more uniform inclusion criteria for clinical trial design. Here, we aimed to review the current clinical trials landscape in non-muscle invasive bladder cancer with respect to these disease states. RECENT FINDINGS: Most active clinical trials focus on high-risk NMIBC in either the BCG-naïve or BCG-unresponsive setting. Strict criteria to define the disease state and a clear pathway to drug registration have encouraged trials for patients with BCG-unresponsive NMIBC. The most promising potential breakthroughs for BCG-naïve patients include alternative BCG strains, immune-priming with intradermal BCG vaccination, and systemic immune checkpoint blockade. The latter therapy is also being actively investigated in multiple trials in BCG-unresponsive NMIBC, along with novel viral agents such as INSTILADRIN (nadofaragene firadenovec) and targeted agents such as oportuzumab monatox. After many years of relative stagnation, multiple new therapies currently under investigation in well-designed clinical trials appear poised for routine clinical implementation in the near future. These therapies should dramatically improve the outcome of patients with NMIBC. We can look forward to the challenges of biomarker-driven drug selection, optimal drug sequencing, and rational combination therapies.

Reactive oxygen species-responsive nanoprodrug with quinone methides-mediated GSH depletion for improved chlorambucil breast cancers therapy.

Prodrug-based stimuli-responsive vectors have emerged as highly promising platform. Inspired by the fact that antioxidant systems including glutathione (GSH) make cancer cells adapt to oxidative stress and play a role in the inactivation of alkylating agents like chlorambucil (CHL) inside tumor cells, while arylboronic acid could transform into GSH depleting agent quinone methide (QM) upon degradation by reactive oxygen species (ROS) over-expressed in tumor cells, a ROS-responsive nanoprodrug (denoted by PPAHC) of CHL was established by integrating CHL into diols-containing hydrophilic polymer with self-immolative linker 4-(hydroxymethyl)phenylboronic acid (HPBA). The prodrug could form core-shell nanoparticle and possess high stability during storage. Drug release profile of PPAHC nanoprodrug demonstrated that nature CHL could be quickly released from PPAHC nanoprodrug in the presence of hydrogen peroxide (H2O2). Moreover, PPAHC nanoprodrug showed improved therapeutic efficiency compared to CHL via anti-proliferative study and cell apoptosis assay. Further measurement of GSH content and ROS levels in tumor cells suggested that the synergistic impact resulted from QM-mediated GSH reduction and CHL-induced further oxidative stress insults to tumor cells. In vivo tumor suppression effect and biocompatibility indicated the superiorities of PPAHC nanoprodrug. Accordingly, PPAHC provides a new approach as a ROS-responsive CHL delivery system and has a great potential for cancer therapy.

Oleanane-, ursane-, and quinone methide friedelane-type triterpenoid derivatives: Recent advances in cancer treatment.

Natural pentacyclic triterpenoids (PTs) have been often reported to exhibit a wide range of biological activities. Among them, the anticancer and anti-inflammatory activities are the most studied. Over the last two decades, the number of publications reporting the anticancer effects of PTs has risen exponentially, reflecting the increasing interest in these natural products for the development of new antineoplastic drugs. Among of the most investigated PTs regarding their anticancer properties are oleanane-, ursane and friedelane-types, including oleanolic, glycyrrhetinic, ursolic and asiatic acids, and celastrol, among others. The extensive research in this field shows that the anticancer effects of PTs are mediated by several mechanisms, as they modulate a diverse range of molecular targets and signaling pathways, involved in cancer cell proliferation and survival. Considering the anticancer potential of this class of compounds, a number of semisynthetic derivatives has been synthetized aiming to improve their therapeutic activity and pharmacokinetic properties, and decrease their toxicity. Some of these new semisynthetic derivatives have shown improved anticancer activity in various cancer cell lines and animal models compared with the parent compound. Moreover, some of these compounds have been assessed in clinical trials, proving to be safe for human use. This review updates the most recent findings on the semisynthetic derivatives of oleanane-, ursane- and quinone methide friedelane-type PTs with anticancer activity. A brief introduction concerning the PTs and their anticancer activity is given, and the main semisynthetic modifications that have been performed between 2012 and early 2017 are reviewed and discussed.

The orthotopic Fischer/AY-27 rat bladder urothelial cell carcinoma model to test the efficacy of different apaziquone formulations.

OBJECTIVES: Apaziquone used intravesically showed significant activity in phase I and II marker lesion studies in non-muscle-invasive bladder cancer. The objective of this study was to assess antitumor activity and safety of 3 different formulations of intravesical apaziquone in an orthotopic rat bladder cancer model. MATERIALS AND METHODS: Female Fischer F344 rats were instilled with 1.5 × 10(6) AY-27 urothelial cell carcinoma cells and divided in 3 treatment groups (n = 10) and 1 placebo group (n = 6). Intravesical treatment was administered for 1 hour on days 2 and 5. Rats were treated with apaziquone in the formulation used in phase I/II clinical trials (group 1); apaziquone with an altered buffering capacity being used in phase III clinical trials (group 2), and apaziquone as in group 2, but without propylene glycol in the diluent (group 3). On days 5 and 14, the bladder wall was inspected by cystoscopy and evaluated for macroscopic tumor growth. After sacrificing the rats (day 14), cystectomy was performed and the bladders were investigated. RESULTS: There were no signs of any toxicity due to the study drug. On histopathologic examination of the bladders 0, 1, and 2 tumors per group were found in group 1, 2, and 3, respectively. In the placebo-treated group, 60% of animals developed tumor, which is comparable to untreated animals. CONCLUSIONS: Apaziquone showed an excellent antitumor activity. The effectiveness of apaziquone in this orthotopic rat bladder tumor model corroborates the clinical observations and implies the validity of this model.

Quinone methides and their prodrugs: a subtle equilibrium between cancer promotion, prevention, and cure.

The importance of reactive drug metabolites in the pathogenesis of drug-induced toxicity has been investigated since the early 1950s, mainly to reveal the link between toxic metabolites and chemical carcinogenesis. This review mainly focuses on biologically active compounds, which generate reactive quinone methide (QM) intermediates either directly or after bioactivation. Several examples of anticancer drugs acting through the generation of QM electrophiles are given. The use of those drugs for chemotherapeutic purposes is also discussed. The key feature of those QM-generating drugs is their reactivity toward specific nucleophilic biological targets. Modulation of their reactivity represents a challenge for medicinal chemists because, depending on the reactivity of these QM intermediates, their interaction with critical proteins can alter the function of these key proteins and induce a wide variety of responses with functional consequences. Among the possible consequences, antiproliferative effects could be exploited for chemotherapeutic purposes. Information on how such QM-generating drugs can affect individual target proteins and their functional consequences are required to help the medicinal chemist in the design of more specific QM-generating molecules for chemotherapeutic use.

Response of multiple recurrent TaT1 bladder cancer to intravesical apaziquone (EO9): comparative analysis of tumor recurrence rates.

OBJECTIVES: Previous studies have demonstrated that intravesical administration of apaziquone (EOquin) has ablative activity against superficial bladder cancer marker lesions with 8 out of 12 complete responses recorded. We present a comparison between the rates of tumor recurrence before and after treatment with apaziquone. METHODS: The rate of tumor recurrence after treatment with apaziquone was compared with each patient's historical record of recurrences obtained from a retrospective analysis of the patients' case notes. The time to each recurrence event before apaziquone treatment and the time to the first recurrence after apaziquone treatment were recorded, and the data were analyzed using a population-averaged linear regression model using Stata Release, version 9.2, software. RESULTS: Of the eight complete responses obtained in the Phase I study, tumor recurrence occurred in 4 patients and the remaining 4 patients remained disease free after a median follow-up of 31 months. The time to the first recurrence after apaziquone treatment was significantly longer (P <0.001) compared with the historical pattern and recurrence interval before apaziquone. Before apaziquone instillation, the mean +/- SE recurrence rate and tumor rate per year was 1.5 +/- 0.2 and 4.8 +/- 1.2, respectively, and these decreased to 0.6 +/- 0.25 and 1.5 +/- 0.8, respectively, after apaziquone treatment (P <0.05). CONCLUSIONS: The results of this study indicate that early recurrences after treatment with apaziquone are infrequent and the interval to recurrence is significantly greater compared with the historical recurrence times for these patients. Larger prospective randomised trials are warranted to confirm these results.

Apaziquone for non-muscle invasive bladder cancer: a critical review.

OBJECTIVE: To describe clinical needs in non-muscle invasive bladder cancer (NMIBC) and review the potential of apaziquone in this respect. METHODS: Epidemiology and clinical practice in NMIBC, as well as new drugs and strategies are reviewed. RESULTS: Bladder cancer is a heterogeneous and frequent disease. Clinical risk factors help in determining additional therapy after initial resection. However, current treatments have clear limitations with regard to efficacy and/or toxicity. New drugs and strategies have been tested recently and are in (pre)clinical use. Intravesical apaziquone (EOquin) is a new drug. It has theoretical advantages for intravesical use, has proven safety and is presently under further clinical evaluation. CONCLUSION: Apaziquone is a promising drug for intravesical use in patients with NMIBC.

Safety and side effects of immediate instillation of apaziquone following transurethral resection in patients with nonmuscle invasive bladder cancer.

PURPOSE: We studied the safety, tolerability and pharmacokinetics of a single immediate post-transurethral resection intravesical instillation of apaziquone for patients with nonmuscle invasive bladder cancer. MATERIALS AND METHODS: Patients with cTa-T1, G1-G2 urothelial cell carcinoma of the bladder underwent transurethral resection of bladder tumor(s) followed by a single intravesical instillation of apaziquone 4 mg/40 ml for 1 hour within 6 hours of transurethral bladder tumor resection. Adverse events and safety parameters were assessed on days 8 and 15 after transurethral bladder tumor resection. Blood samples were drawn before and during the instillation for pharmacokinetic analyses. The first 10 patients with pTa-T1, G1-G2 nonmuscle invasive bladder cancer were also evaluated by cystoscopy 3 months after treatment to determine mucosal healing. RESULTS: Of 20 patients receiving apaziquone 13 (65%) reported 35 adverse events, mostly grade 1 to 2. Eight patients (40%) reported 13 adverse events related to treatment, in particular dysuria, hematuria, bladder spasm, abdominal pain, asthenia and postoperative urinary retention. Three grade 3 and 1 grade 4 event(s) occurred, but these were considered unrelated to treatment. No other significant clinical changes were observed. Apaziquone and the active metabolite EO5a were not detected with pharmacokinetic analyses at any point of time. After 3 months no evidence of impaired mucosal healing was observed. CONCLUSIONS: A single immediate post-transurethral bladder tumor resection instillation of apaziquone was well tolerated with an expected good safety profile. Apaziquone and its metabolite EO5a were not detected systemically with pharmacokinetic analyses. These results have lead to further study of a single immediate instillation of apaziquone.

Cytotoxicity and p-glycoprotein modulating effects of quinolones and indoloquinazolines from the Chinese herb Evodia rutaecarpa.

The antimycobacterial quinolones 1-methyl-2-undecyl-4-quinolone, dihydroevocarpine and evocarpine as well as the indoloquinazoline alkaloids rutaecarpine and evodiamine - all from the Chinese medicinal herb Evodia rutaecarpa - were tested in two in vitro assays, for cytotoxicity and interaction with p-glycoprotein (p-gp). Cytotoxicity was measured in a cell proliferation assay against CCRF-CEM leukemia cells and their p-gp over-expressing subline CEM/ADR5000. An assay monitoring the p-gp-dependent accumulation of the dye calcein in porcine brain capillary endothelial cells (PBCECs) was used to study interactions of the test substances with this efflux pump. Rutaecarpine and evodiamine showed quite high toxicity with IC (50) values from 2.64 to 4.53 microM and were weak modulators of p-gp activity. The degrees of resistance in CEM/ADR5000 towards the saturated quinolones 1-methyl-2-undecyl-4-quinolone and dihydroevocarpine were between 3 and 4. In the calcein assay, these two quinolones were shown to be moderate modulators of p-gp activity. Evocarpine, on the other side, is not transported by p-gp, and showed only slight toxicity at the highest test concentration of 30 microM.

Stability experiments in human urine with EO9 (apaziquone): a novel anticancer agent for the intravesical treatment of bladder cancer.

EO9 (apaziquone) is a novel, promising anticancer agent, which is currently being investigated for the intravesical treatment of bladder cancer. EO9 contains a highly reactive aziridine ring in its structure that limits its chemical stability in acidic aqueous solutions. The stability of the pharmaceutically formulated EO9 in human urine, including the effects of several parameters such as temperature, buffer strength and pH have been investigated. Urine extracts were analyzed by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry (HPLC-MS/MS) using a TurboIonspray interface and positive-ion multiple reaction monitoring. EO9 was unstable in urine at 43 degrees C during the instillation for longer than 1 h. However, the drug was stable in human urine for 3 h at 37 degrees C. EO9 is stable in urine stabilized with TRIS buffer (pH 9.0; 5 mM) for up to three freeze/thaw cycles at -20 and -70 degrees C and 3 months of storage at -70 degrees C. The results also illustrated that with the lower pH in urine, EO9 became more unstable. Furthermore, a new degradation product of EO9 was discovered and successfully identified as EO9-Cl. The outcomes of these stability experiments will be implemented to insure proper sample handling at the clinical sites, transport, storage, and sample handling during analysis in the forthcoming preclinical studies of EO9 in superficial bladder cancer, supported by bioanalysis and pharmacokinetic monitoring.

Hypoxia: targeting the tumour.

Solid tumours contain regions of very low oxygen concentrations that are said to be hypoxic. Hypoxia is a natural phenotype of solid tumours resulting from an imperfect vascular network. There are a number of consequences associated with tumour hypoxia including: resistance to ionising radiation, resistance to chemotherapy and the magnification of mutated p53. In addition tissue hypoxia has been regarded as a key factor for tumour aggressiveness and metastasis by activation of signal transduction pathways and gene regulatory mechanisms. It is clear that hypoxia in solid tumours promotes a strong oncogenic phenotype and is a phenomenon that occurs in all solid tumours. As such this provides a significant target for drug discovery particularly for tumour-targeting agents. A range of chemical classes (N-oxides, quinones, nitro-aromatics) have been explored as bioreductive agents that target tumour hypoxia. The most advanced agent, tirapazamine, is in phase III clinical trials in combination with cis-platin. The aim of this review is to give a brief overview of the current molecules and strategies being explored for targeting tumour hypoxia.