The cardioprotective actions of statins in targeting mitochondrial dysfunction associated with myocardial ischaemia-reperfusion injury.

During cardiac reperfusion after myocardial infarction, the heart is subjected to cascading cycles of ischaemia reperfusion injury (IRI). Patients presenting with this injury succumb to myocardial dysfunction resulting in myocardial cell death, which contributes to morbidity and mortality. New targeted therapies are required if the myocardium is to be protected from this injury and improve patient outcomes. Extensive research into the role of mitochondria during ischaemia and reperfusion has unveiled one of the most important sites contributing towards this injury; specifically, the opening of the mitochondrial permeability transition pore. The opening of this pore occurs during reperfusion and results in mitochondria swelling and dysfunction, promoting apoptotic cell death. Activation of mitochondrial ATP-sensitive potassium channels (mitoKATP) channels, uncoupling proteins, and inhibition of glycogen synthase kinase-3ß (GSK3ß) phosphorylation have been identified to delay mitochondrial permeability transition pore opening and reduce reactive oxygen species formation, thereby decreasing infarct size. Statins have recently been identified to provide a direct cardioprotective effect on these specific mitochondrial components, all of which reduce the severity of myocardial IRI, promoting the ability of statins to be a considerate preconditioning agent. This review will outline what has currently been shown in regard to statins cardioprotective effects on mitochondria during myocardial IRI.

Does Crizotinib Auto-Inhibit CYP3A in vivo?

Crizotinib is a tyrosine kinase inhibitor used to treat anaplastic lymphoma kinase-positive lung cancer. There is in vitro evidence that crizotinib may auto-inhibit cytochrome P450 3A (CYP3A) activity, with important implications for crizotinib pharmacokinetics. In order to test whether crizotinib treatment alters CYP3A activity in vivo, mice were treated with 5 and 25 mg/kg crizotinib (p.o.) daily for 14 days. Results showed that crizotinib treatment did not alter CYP3A activity as determined by erythromycin N-demethylation. In addition, CYP3A polypeptide expression as measured by Western blot was unchanged. Therefore, our results do not support CYP3A inhibition by crizotinib in vivo.

Effect of Cannabinoid Receptor Agonists on Isolated Rat Atria.

Cannabinoid CB2 receptor agonists are under investigation for clinical use. At the same time, synthetic cannabinoids have been implicated in a number of deaths. One cause of death is thought to be cardiac arrest subsequent to extreme tachycardia. Central mechanisms are thought to play a role in this, with CB1 but not CB2 receptors thought to mediate central effects. However, the direct effects of cannabinoids on the heart are less well understood. We therefore tested the effects of cannabinoids on isolated rat atria to test whether activation of myocardial CB1 and CB2 receptors could contribute to tachycardia. Although we found a moderate effect that can be attributed to CB1 receptors, we did not find any evidence for chronotropic effects by a CB2 receptor activation. Our results indicate that cannabinoid cardiotoxicity may partially involve CB1 receptors in the myocardium, and that CB2 receptor agonists are unlikely to have significant effects on the heart.

Induction of glucose intolerance by acute administration of rimonabant.

BACKGROUND/AIMS: Rimonabant is a cannabinoid CB1 receptor antagonist. Other CB1 antagonists have biphasic effects on blood glucose levels following acute administration. We therefore tested the effects of rimonabant on glucose tolerance following acute administration. METHODS: We tested the effects of oral and intracerebroventricular administration of rimonabant on blood glucose and gastrointestinal transit in mice following oral and intravenous glucose challenge. RESULTS: We found a dose-dependent increase in blood glucose from oral doses of rimonabant of 3 mg/kg and above. WIN55,212-2 (3 mg/kg), a cannabinoid receptor agonist, did not influence blood glucose in the presence or absence of rimonabant. Rimonabant did not induce release of glucose from isolated rat hepatocytes or modify serum insulin concentration in mice. Intracerebroventricular administration of rimonabant caused increases in blood glucose and gastrointestinal transit, suggesting a central nervous system site of action. Increases in blood glucose by rimonabant were partially blocked by the dopamine receptor antagonist haloperidol and significantly blocked by the 5-hydroxytryptophan(5-HT) depleting agent p-CPA and the 5-HT 3 receptor antagonist ondansetron. CONCLUSIONS: Rimonabant causes dose-dependent increase in glucose profile upon glucose challenge partially mediated by the central nervous system control of gastrointestinal carbohydrate absorption through pathways that are modulated by both 5-HT and dopamine.

Experimental Determination of Cancer Drug Targets with Independent Mechanisms of Resistance.

Mathematical modelling of tumour mutation dynamics has suggested that cancer drug targets that have different resistance mechanisms should be good candidates for combination treatment. This is because the development of mutations that cause resistance to all drugs at once should arise relatively infrequently. However, it is difficult to identify drug targets fulfilling this requirement for particular cancers. Here we present four experimental criteria that we argue are necessary (but not sufficient) conditions that drug combinations should meet in order to be considered for combination drug treatment aimed at delaying or overcoming cancer drug resistance. We present the results of our own experiments - guided by these criteria - using anaplastic lymphoma kinase mutated lung cancer cells. Each set of experiments demonstrate results for different drug combinations. We conclude that the combination of ALK and MEK inhibitors come closest to meeting all our criteria.

Lung Cancer Attracts Greater Stigma than Other Cancer Types in Aotearoa New Zealand.

Background: Lung cancer is the leading cause of cancer death in Aotearoa New Zealand, killing over 1,700 people each year. Despite the burden of lung cancer in Aotearoa New Zealand, the popular press has referred to it as the cancer type that no one talks about. Here, we investigate one factor that may contribute to this state of affairs: lung cancer stigma. Methods: Participants were university students and members of the general public. University students were recruited via an online experiment participation system in 2021. Members of the public were recruited via social media. All participants completed the Cancer Stigma Scale (CSS) for one of five cancer types (lung, cervical, breast, skin, or bowel). The CSS is a 25-item scale with six subscales: awkwardness, avoidance, severity, policy opposition, personal responsibility, and financial discrimination. Results: The mean age of participants was 24.3 (Standard Deviation = 10.4). Data from each subscale were submitted to an analysis of covariance (ANCOVA), with cancer type as a between-participant factor (5: lung, cervical, breast, skin, or bowel) and stigma as the dependent variable. Relative to most other cancer types, people were more likely to avoid someone with lung cancer, view interacting with someone with lung cancer as more awkward, and view people with lung cancer as being responsible for their condition. Conclusion: The Health Research Council of New Zealand recently funded the very first trial of lung cancer screening in Aotearoa New Zealand. The current study suggests that addressing stigma will be essential for the success of such programs, with stigma likely influencing those who engage in such trials.

Considerations for Whole-Slide Analysis of Murine Xenografts Experiments.

Histochemistry of tumor sections is a widely employed technique utilized to examine cell death in preclinical xenograft animal models of cancer. However, this is under the assumption that tumors are homogeneous, leading to practices such as automatic cell counting across the entire section. We have noted that in our experiments the core of the tumor is largely or partially necrotic, and lacks evidence of vascularization (in contrast to the outer areas of the tumor). We note that this can bias and confound immunohistochemical analyses that do not take care to sample areas of interest in a way to take this into account. Design-based stereology with image analysis techniques is an alternative process that could be used to measure the volume of the necrotic region compared to the volume of the whole tumor.

Synthesis and Biological Evaluation of (-) and (+)-Spiroleucettadine and Analogues.

A second-generation enantiospecific synthesis of spiroleucettadine is described. The original reported antibacterial activity was not observed when the experiment was repeated on the synthetic samples; however, significant anti-proliferative activity was uncovered for both enantiomers of spiroleucettadine. Comparison of the optical rotational data and ORD-CD spectra of both enantiomers and the reported spectrum from the natural source have not provided a definitive answer regarding the absolute stereochemistry of naturally occurring spiroleucettadine. Efforts then focussed on alteration at the C-4 and C-5 positions of the slightly more active (-)-spiroleucettadine. Ten analogues were synthesised, with three analogues found to possess similar anti-proliferative profiles to spiroleucettadine against the H522 lung cancer cell line.

Behavioural effects of co-administration of delta9-tetrahydrocannabinol with fluoxetine in rats.

Previous studies have suggested panic induced by cannabinoids may be potentiated by concurrently using selective serotonin reuptake inhibitors. We therefore tested for panic and anxiety-related behaviour in rats coadministered with the selective serotonin reuptake inhibitor fluoxetine hydrochloride and the CB1 agonist delta9-tetrahydrocannabinol. Although each drug alone elicited behaviours consistent with previous studies, we did not find that coadministration of these drugs potentiated or reduced the effects of either drug alone. Specifically, fluoxetine treatment did not cause any increase in freezing behaviour, decrease in social interaction or exploration in an adverse environment, change preference for outer or inner zones, or modulate rearing behaviour in rats receiving delta9-tetrahydrocannabinol.

A radical hypothesis on the nature of sleep.

Dexamethasone has been observed to cause night-time wakefulness without accompanying fatigue. It is proposed here that the drug interrupts a sleep signal, and that although sleep has an ultimate ecological function, this signal is a proximate mechanism but not an ultimate physiological necessity, such that sleep is not a necessity.

Is Cannabis Harmless? Focus on Brain Function.

BACKGROUND: The degree to which cannabis use causes long term harm to mental functioning is contentious. OBJECTIVE: To determine the evidence for residual and long term effects of cannabis use on mental functions. METHOD: Comprehensively review human studies addressing detrimental effects on human mental and life functioning. RESULTS: Heavy use causes immediate effects on perception, mood and sedation, but also deficits in cognitive ability. But cessation following heavy use has withdrawal effects and is associated with residual effects on cognition that may last for several weeks. Heavy use also raises the risk of impoverishment of life outcomes and a decline in socioeconomic status as well as the risk of mental health problems. Young age at the start of heavy cannabis use causes a risk of lifelong detrimental effects, and as a worst case together with genetic vulnerability exacerbate a predisposition to schizophrenia. CONCLUSION: Heavy regular use of cannabis that begins in adolescence heightens the risk of longterm impairment of life and mental functioning.

What is medicinal cannabis?

As New Zealand considers cannabis legal reform, we ask: what exactly is medicinal cannabis, and why does this matter? Cannabis is not a single entity but comes in diverse forms with various active ingredients. This contrasts with the legal and pharmaceutical definitions of medicines, with wide-ranging implications for quality control, prescriber practice and the assessment of clinical evidence. We argue that what is considered a medicine in the legal and pharmaceutical sense should not be changed in an ad hoc way to accommodate cannabis, but that cannabis products should be held to the same standards as other medicines.

Does the mouse tail vein injection method provide a good model of lung cancer?

Lung cancer drug development requires screening in animal models. We aimed to develop orthotopic models of human non-small lung cancer using A549 and H3122 cells delivered by tail vein injection. This procedure has been used previously for a mouse lung cancer (Lewis lung carcinoma) and as a model of human breast cancer metastasis to lung. We report that the procedure led to poor animal condition 7-8 weeks after injection, and produced lesions in the lungs visible at necropsy but we were unable identify individual cancer cells using immunohistochemistry. We conclude that if this method is to produce a model that can be used in drug experiments, improvements are required for cancer cell detection post mortem, such as by using of a fluorescently tagged human lung cancer cell line.

Cytotoxicity of curcumin derivatives in ALK positive non-small cell lung cancer.

Non-small cell lung cancer with ALK rearrangements can be targeted effectively with ALK inhibitors such as crizotinib. However, cancer progression typically occurs within a year as drug resistance develops. One strategy to overcome this drug resistance is to determine if novel cytotoxic agents retain the ability to kill lung cancer cells that have developed ALK inhibitor resistance. We therefore examined curcumin, a drug with anticancer properties, and 2 s-generation curcumin derivatives (1-methyl-3,5-bis[(E)-4-pyridyl) methylidene]-4-piperidone (RL66) and 1-isopropyl-3,5-bis[(pyridine-3-yl) methylene]piperidin-4-one (RL118)) in lung cancer cell lines. The cytotoxicity of curcumin, RL66, and RL118 were tested in both ALK+ lung cancer cells (H3122), crizotinib resistant ALK+ cells (CR-H3122) and ALK- lung cancer cells (A549), both alone and in combination with crizotinib. ALK+ cells were 2-3x more sensitive to RL66 and RL118 than ALK- cells, with the drugs' eliciting IC50 values in the range of 0.7-1 µM in H3122 cells. Retained cytotoxic potency of the curcumin derivatives in crizotinib resistant cells indicated that mechanisms of resistance to the two drug types are independent, with resistance to ALK inhibitors not necessarily causing cross-resistance to curcumin derivatives. This was further corroborated by drug combination analysis where the effect of the drugs in combination was consistent with Bliss additivity, consistent with independent targets for crizotinib and curcumin derivatives. Results from Western blotting showed that RL118 (2 µM) inhibited p-ALK/ALK by ~50%, which was not as potent as the 90% inhibition elicited by crizotinib (0.25 µM). Since this is the primary mechanism of crizotinib cytotoxicity this provides further evidence of independent mechanisms of toxicity.

Cannabinoid CB1 and CB2 receptor ligand specificity and the development of CB2-selective agonists.

Cannabinoids in current use such as nabilone activate both CB1 and CB2 receptors. Selective CB2 activation may provide some of the therapeutic effects of cannabinoids, such as their immuno-modulatory properties, without the psychoactive effects of CB1 activation. Therefore, cannabinoid CB2 receptors represent an attractive target for drug development. However, selective and potent CB2 agonists remain in development. CB1 and CB2 differ considerably in their amino acid sequence and tertiary structures. Therefore, clinical development of potent and selective CB2 agonists is probable. Mutational and ligand binding studies, functional mapping, and computer modelling have revealed key residues and domains in cannabinoid receptors that are involved in agonist and antagonist binding to CB1 and CB2. In addition, CB2 has undergone more rapid evolution, and results for ligand binding and efficacy cannot be automatically extrapolated from rat or mouse CB2 to human. Furthermore, loss of CB1 affinity is a crucial property for CB2-selective ligands, and although rat CB1 is 97% homologous with human CB1, critical differences do exist, with potential for further exploitation in drug design. In this paper we briefly review previous cannabinoid receptor models and mutation/binding studies. We also review binding affinity ratios with respect to CB1 and CB2. We then employ our own models to illustrate key cannabinoid receptor residues and binding subdomains that are involved in these differences in binding affinities and discuss how these might be exploited in the development of CB2 specific ligands. Published reports for species specific binding affinities for CB2 are scarce, and we argue that this needs to be corrected prior to the progression of CB2 agonists from pre-clinical to clinical research.

Cannabinoids for the treatment of neuropathic pain: clinical evidence.

Neuropathic pain is a worldwide epidemic that occurs in 3 to 8% of individuals in industrialized countries and is often refractory to existing treatments. Drugs currently available to target neuropathic pain are, at best, moderately effective and include antidepressants, gabapentin, NMDA receptor antagonists, as well as other anticonvulsants, all of which are limited by their adverse-effect profiles. Cannabinoid drugs are emerging as a promising class of drugs to treat neuropathic pain and have been tested for analgesic effects in a range of chronic pain conditions. Data show that cannabinoids are often effective in individuals with refractory pain receiving concomitant analgesic drugs. Clinical studies on cannabinoids for the treatment of neuropathic pain are reviewed, focusing on clinical trials published within the last five years. Data from large, well-controlled studies show that cannabinoids are moderately effective in reducing chronic pain and that side effects are comparable to existing treatments, suggesting that cannabinoids can play a useful role in the management of chronic pain. Like other drugs for neuropathic pain, cannabinoids have a dose titration that is limited by psychoactive side effects. The development of cannabinoid drugs to target neuropathic pain with improved therapeutic ratios will depend upon the development of cannabinoid treatments with reduced psychoactivity.

The effect of delta 9-tetrahydrocannabinol on the extinction of an adverse associative memory.

The cannabinoid Delta(9)-tetrahydrocannabinol (Delta(9)-THC) is currently being employed or tested for a number of therapeutic uses. Cannabinoid CB1 receptors are critically involved in adverse memory extinction. It is not known whether an unintended effect of Delta(9)-THC is increased extinction rates of adverse memories. We therefore tested the effect of Delta(9)-THC on adverse memory extinction using an auditory-stimulus/foot shock paradigm. We found that repeated administration of a high dose of Delta(9)-THC over 6 days retarded extinction compared with controls. This is in contrast to other reports and might be a result of endocannabinoid signalling dysfunction due to cannabinoid receptor densensitization.

It has not been proven why or that most research findings are false.

The claim has been made that it can be proven that most published findings in medical, biological, and allied sciences are false and that the reason for this can be proven and explained with a mathematical model. It has not, however, been mathematically proven that most research findings are false, and this can be proven. The model used in the proof is incoherent and has been falsified. Furthermore, advice to researchers derived from the model is misleading and distracts from more important issues in experimental standards.