Ketamine inhibits colorectal cancer cells malignant potential via blockage of NMDA receptor

Esketamine alleviates ferroptosis-mediated acute lung injury by modulating the HIF-1α/HO-1 pathway

BACKGROUND

Alveolar epithelial cell (AEC) ferroptosis contributes to the progression of acute lung injury (ALI). Esketamine (ESK) is a new clinical sedative, anesthetic, and analgesic drug that has attracted substantial attention in mental health research because of its antidepressant effects. However, the effects of ESK on ferroptosis-mediated ALI remain unclear.

OBJECTIVE

This study aimed to explore the protective effect of ESK on AEC ferroptosis in ALI and its potential molecular mechanism in vivo and in vitro.

METHODS

The antiferroptotic and anti-inflammatory effects of ESK were assessed in a mouse model of lipopolysaccharide (LPS)-induced ALI. In vitro, the epithelial cell lines MLE-12 and A549 were used to examine the underlying mechanism by which ESK regulates inflammation and ferroptosis.

RESULTS

ESK protected mice against LPS-induced ALI, significantly attenuated pathological changes in the lungs and decreased inflammation and ferroptosis. In vitro, ESK inhibited LPS-induced inflammation and ferroptosis in MLE-12 and A549 cells. Moreover, ferroptosis mediated inflammation in LPS-induced ALI in vivo and in vitro, and ESK decreased the LPS-induced inflammatory response by suppressing ferroptosis. ESK promoted the HIF-1α/HO-1 pathway in LPS-treated AECs and in the lung tissues of mice with LPS-induced ALI. Moreover, pretreatment with ESK and the HIF-1α stabilizer dimethyloxaloylglycine (DMOG) substantially attenuated lung injury and prevented changes in ferroptosis-related biochemical indicators, including glutathione (GSH) depletion, malondialdehyde (MDA) production and glutathione peroxidase 4 (GPX4) downregulation, in untreated LPS-induced mice but not in LPS-induced mice treated with the HO-1 inhibitor zinc protoporphyrin (ZNPP). Similar effects were observed in vitro in HO-1 siRNA-transfected A549 cells after LPS incubation but not in control siRNA-transfected cells.

CONCLUSION

ESK can inhibit ferroptosis-mediated lipid peroxidation by increasing the expression of HIF-1α/HO-1 pathway, highlighting the potential of ESK to treat LPS-induced ALI.

Efficacy of GluN2B-Containing NMDA receptor antagonist for antitumor and antidepressant therapy in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the predominant subtype of lung cancer. Evidence suggests that the ionotropic glutamate receptor N-methyl-D-aspartate (NMDA) receptor, a critical molecule in the central nervous system, is expressed in NSCLC. However, the specific expression patterns, subcellular localization, functional modulation, and pathological implications of NMDA receptor subtypes in NSCLC have not been fully elucidated. In this study, we employed a multi-disciplinary approach, combining biochemical and molecular biology with electrophysiological recordings and behavioral assays, to investigate these aspects. We reveal the expression of GluN2B-containing NMDA receptors in A549 and H460 NSCLC cell lines and the induction of NMDA receptor-mediated currents by glutamate in A549 cells. Furthermore, the GluN2B-specific inhibitors ifenprodil and Ro 25-6981 significantly reduced cell viability and migration, while promoting apoptosis. Importantly, intraperitoneal administration of ifenprodil in nude mice inhibited the growth of subcutaneous tumors derived from A549 and H460 cells and ameliorated depression-like behaviors. These findings underscore the potential antiproliferative effects of ifenprodil and Ro 25-6981 and suggest that GluN2B-containing NMDA receptors may represent novel therapeutic targets for NSCLC, with the added benefit of potential antidepressant action.

The role of perioperative factors in the prognosis of cancer patients: A coin has two sides

Cancer, the second leading cause of mortality globally, poses a significant health challenge. The conventional treatment for solid tumors involves surgical intervention, followed by chemo- and radio-therapies as well as target therapies, but the recurrence and metastasis of cancers remain a major issue. Anesthesia is essential for ensuring patient comfort and safety during surgical procedures. Despite its crucial role during the surgery, the precise effect of anesthesia on cancer patient outcomes is not clearly understood. This comprehensive review aims to elucidate the various anesthesia strategies used in the perioperative care of cancer patients and their potential effects on patients' prognosis, but understanding the complex relationship between anesthesia and cancer outcomes is crucial, given the complexity in cancer treaments. Examining potential implications of anesthesia strategies on cancer patient prognosis may help better understand treatment efficacy and risk factors of cancer recurrence and metastasis. Through a detailed analysis of anesthesia practices in cancer surgery, this review aims to provide insights that may lead to improving the existing anesthesia protocols and ultimately reduce risk factors for patient outcomes in the field of oncology.

Perioperative Ketamine and Cancer Recurrence: A Comprehensive Review

Cancer is a significant global health threat and a leading cause of death worldwide. Effective early-stage interventions, particularly surgery, can potentially cure many solid tumors. However, the risk of postoperative cancer recurrence remains high. Recent research highlights the influence of perioperative anesthetic and analgesic choices on the fate of residual cancer cells, potentially affecting recurrence risks. Among these agents, ketamine-a well-known anesthetic and analgesic-has garnered interest due to its antitumor properties, mainly through inhibiting the N-methyl-D-aspartate (NMDA) receptor found in various cancer tissues. Additionally, ketamine's potential immunomodulatory effects, given the expression of NMDA receptors on immune cells, suggest that it plays a significant role during the perioperative period. This review synthesizes current evidence on ketamine's impact on cancer cell biology, inflammation, immune modulation, and the role of the gut microbiota, proposing ketamine as a promising agent for enhancing oncological outcomes.

Esketamine induces apoptosis of nasopharyngeal carcinoma cells through the PERK/CHOP pathway

Nasopharyngeal carcinoma, a malignant tumor prevalent in southeast Asia and north Africa, still lacks effective treatment. Esketamine, an N-methyl-D-aspartatic acid (NMDA) receptor (NMDAR) antagonist, is widely used in clinical anesthesia. Emerging evidence suggests that esketamine plays an important role in inhibiting tumor cell activity. However, the underlying mechanisms of esketamine on nasopharyngeal carcinoma remain unknown. In this study, we found that esketamine inhibited the proliferation and migration of nasopharyngeal carcinoma cells. Mechanically, transcriptome sequencing and subsequent verification experiments revealed that esketamine promoted the apoptosis of nasopharyngeal carcinoma cells through endoplasmic reticulum stress PERK/ATF4/CHOP signaling pathway mediated by NMDAR. Additionally, when combined with esketamine, the inhibitory effect of cisplatin on the proliferation of nasopharyngeal carcinoma cells was significantly enhanced. These findings provide new insights into future anti-nasopharyngeal carcinoma clinical strategies via targeting the NMDAR/PERK/CHOP axis alone or in combination with cisplatin.

Potential 'anti-cancer' effects of esketamine on proliferation, apoptosis, migration and invasion in esophageal squamous carcinoma cells

BACKGROUND

Esketamine, an N-methyl-D-aspartate receptor antagonist, is commonly used for anesthesia and analgesia clinically. It was reported to negatively regulate cell proliferation, metastasis and apoptosis in cancer cells, including lung cancer and pancreatic cancer. However, its impact on esophageal squamous cell carcinoma (ESCC) malignance and underlying mechanism remain elusive. This study was aimed to investigate the antitumor effects of esketamine on ESCC in vitro.

METHODS

ESCC cell lines (KYSE-30 and KYSE-150) were cultured and treated with different concentrations (0.1, 0.2, 0.4, 0.8, 1, 2 mM) of esketamine. Their proliferation, apoptosis, migration and invasion were assessed with various assays. Furthermore, mass spectrometry-based proteomic analysis and GO/KEGG enrichment analysis were applied to characterize the differentially expressed proteins (DEPs) with or without esketamine treatment. Some key proteins identified from proteomic analysis were further validated with Western blotting and bioinformatics analysis.

RESULTS

Esketamine significantly inhibited the proliferation, migration, invasion and promoted apoptosis of the both types of cell lines in a dose- and time-dependent manner. A total of 321 common DEPs, including 97 upregulated and 224 downregulated proteins, were found with HPLC-MS analyses. GO/KEGG enrichment analysis suggested that esketamine affected cell population proliferation, GTPase activity and Apelin signaling pathway. The ERCC6L, AHR and KIF2C protein expression was significantly downregulated in these ESCC cells treated with esketamine compared to the controls and their changes were associated with the suppressive effects of esketamine on ESCC through bioinformatics analysis.

CONCLUSIONS

Our work demonstrated that esketamine has potential anti-ESCC properties in vitro but subjected to further in vivo and clinical study.

Compounds targeting ferroptosis in breast cancer: progress and their therapeutic potential

In recent years, there has been a significant increase in the incidence of Breast cancer (BC), making it the most common cancer among women and a major threat to women's health. Consequently, there is an urgent need to discover new and effective strategies for treating BC. Ferroptosis, a novel form of cell death characterized by the accumulation of iron-dependent lipid reactive oxygen species, has emerged as a distinct regulatory pathway separate from necrosis, apoptosis, and autophagy. It is widely recognized as a crucial factor in the development and progression of cancer, offering a promising avenue for BC treatment. While significant progress has been made in understanding the mechanisms of ferroptosis in BC, drug development is still in its early stages. Numerous compounds, including phytochemicals derived from dietary sources and medicinal plants, as well as synthetic drugs (both clinically approved medications and laboratory reagents), have shown the ability to induce ferroptosis in BC cells, effectively inhibiting tumor growth. This comprehensive review aims to examine in detail the compounds that target ferroptosis in BC and elucidate their potential mechanisms of action. Additionally, the challenges associated with the clinical application of ferroptosis-inducing drugs are discussed, offering valuable insights for the development of novel treatment strategies for BC.

HIF-1α/MMP-9 promotes spinal cord central sensitization in rats with bone cancer pain

Bone cancer pain (BCP) is one of the most prevalent and serious symptoms of patients with cancer. Currently, the medical interventions used for the treatment of BCP do not act with optimal safety and efficacy. In this study, we appraised whether the hypoxia-inducible factor 1α (HIF-1α)/metalloproteinase-9 (MMP9) axis activates the PI3K/AKT pathway, resulting in elevated spinal cord central sensitization and aggravated BCP. BCP rats were established by tibial injection of Walker 256 cells, followed by different interventions in rats using HIF-1ɑ inhibitor LW6 or antibody treatments. After treatment with LW6 or antibody against HIF-1α, central sensitization in the spinal cord tissues of rats was inhibited, and pain perception in rats was reduced. Moreover, the activation of glial cells in the spinal cord tissues was ameliorated. The expression of MMP9 was remarkably suppressed in spinal cord tissues after inhibition of HIF-1ɑ activity, and the activity of the PI3K/AKT signaling pathway was inhibited. Further activation of MMP9 expression suppressed the alleviating effect of HIF-1ɑ inhibitor LW6 or antibody on pain perception in rats inoculated with tumors. Taken together, our studies suggest a HIF-1α/MMP9-mediated activation of PI3K/AKT in the spinal cord tissues, resulting in increased pain perception in a rat model with BCP.

NMDA Receptor Glycine Binding Site Modulators for Prevention and Treatment of Ketamine Use Disorder

Ketamine offers a fast-acting approach to relieving treatment-resistant depression, but its abuse potential is an issue of concern. As ketamine is a noncompetitive N-methyl-D-aspartate receptor (NMDAR) ion channel blocker, modulation of NMDAR might be an effective strategy to counteract the abuse liability of ketamine and even to treat ketamine use disorder. This study evaluated whether NMDAR modulators that act on glycine binding sites can decrease motivation to obtain ketamine and reduce reinstatement to ketamine-seeking behavior. Two NMDAR modulators, D-serine and sarcosine were examined. Male Sprague-Dawley rats underwent training to acquire the ability to self-administer ketamine. The motivation to self-administer ketamine or sucrose pellets was examined under a progressive ratio (PR) schedule. The reinstatement of ketamine-seeking and sucrose pellet-seeking behaviors were assessed after extinction. The results showed that both D-serine and sarcosine significantly decreased the breakpoints for ketamine and prevented reinstatement of ketamine seeking. However, these modulators did not alter motivated behavior for sucrose pellets, the ability of the cue and sucrose pellets to reinstate sucrose-seeking behavior or spontaneous locomotor activity. These findings indicate that two NMDAR modulators can specifically reduce the measures of motivation and relapse for ketamine in rats, suggesting that targeting the glycine binding site of the NMDAR is a promising approach for preventing and treating ketamine use disorder.

Tumor Necrosis Factor Alpha: Implications of Anesthesia on Cancers

Cancer remains a major public health issue and a leading cause of death worldwide. Despite advancements in chemotherapy, radiation therapy, and immunotherapy, surgery is the mainstay of cancer treatment for solid tumors. However, tumor cells are known to disseminate into the vascular and lymphatic systems during surgical manipulation. Additionally, surgery-induced stress responses can produce an immunosuppressive environment that is favorable for cancer relapse. Up to 90% of cancer-related deaths are the result of metastatic disease after surgical resection. Emerging evidence shows that the interactions between tumor cells and the tumor microenvironment (TME) not only play decisive roles in tumor initiation, progression, and metastasis but also have profound effects on therapeutic efficacy. Tumor necrosis factor alpha (TNF-α), a pleiotropic cytokine contributing to both physiological and pathological processes, is one of the main mediators of inflammation-associated carcinogenesis in the TME. Because TNF-α signaling may modulate the course of cancer, it can be therapeutically targeted to ameliorate clinical outcomes. As the incidence of cancer continues to grow, approximately 80% of cancer patients require anesthesia during cancer care for diagnostic, therapeutic, or palliative procedures, and over 60% of cancer patients receive anesthesia for primary surgical resection. Numerous studies have demonstrated that perioperative management, including surgical manipulation, anesthetics/analgesics, and other supportive care, may alter the TME and cancer progression by affecting inflammatory or immune responses during cancer surgery, but the literature about the impact of anesthesia on the TNF-α production and cancer progression is limited. Therefore, this review summarizes the current knowledge of the implications of anesthesia on cancers from the insights of TNF-α release and provides future anesthetic strategies for improving oncological survival.

Emerging Roles of the Nervous System in Gastrointestinal Cancer Development

Simple Summary

Nerve–cancer cross-talk has increasingly become a focus of the oncology field, particularly in gastrointestinal (GI) cancers. The indispensable roles of the nervous system in GI tumorigenesis and malignancy have been dissected by epidemiological, experimental animal and mechanistic data. Herein, we review and integrate recent discoveries linking the nervous system to GI cancer initiation and progression, and focus on the molecular mechanisms by which nerves and neural receptor pathways drive GI malignancy.

Abstract

Our understanding of the fascinating connection between nervous system and gastrointestinal (GI) tumorigenesis has expanded greatly in recent years. Recent studies revealed that neurogenesis plays an active part in GI tumor initiation and progression. Tumor-driven neurogenesis, as well as neurite outgrowth of the pre-existing peripheral nervous system (PNS), may fuel GI tumor progression via facilitating cancer cell proliferation, chemoresistance, invasion and immune escape. Neurotransmitters and neuropeptides drive the activation of various oncogenic pathways downstream of neural receptors within cancer cells, underscoring the importance of neural signaling pathways in GI tumor malignancy. In addition, neural infiltration also plays an integral role in tumor microenvironments, and contributes to an environment in favor of tumor angiogenesis, immune evasion and invasion. Blockade of tumor innervation via denervation or pharmacological agents may serve as a promising therapeutic strategy against GI tumors. In this review, we summarize recent findings linking the nervous system to GI tumor progression, set the spotlight on the molecular mechanisms by which neural signaling fuels cancer aggressiveness, and highlight the importance of targeting neural mechanisms in GI tumor therapy.

Clinical Uses of Ketamine in Children: A Narrative Review

Ketamine is a phencyclidine derivative that acts as a noncompetitive N-methyl-D-aspartate as well as a glutamate receptor antagonist. It also has other minor mechanisms that contribute to its extensive drug profile. Ketamine is a bronchodilator and maintains normal airway reflexes and, thus, permits spontaneous respiration. This, coupled with the fact that it produces potent analgesia, makes it highly suitable for children.

Despite its many merits, the drug’s side effects, along with its cultural image of being a drug of abuse, a drug used in veterinary medicine, or a “date-rape drug” have sullied its reputation within the armamentarium of medicine. Even though it is widely used in developing countries, its use in Western nations has diminished. We have strived to explore the various clinical uses of ketamine in children through this article. In addition, the article also highlights how some of the fears associated with using the drug are unfounded and provides ways by which the drug’s side effects can be prevented and managed.

Ketamine; history and role in anesthetic pharmacology

Ketamine (Ket) was developed in 1962 as a less hallucinogenic and shorter acting agent than phencyclidine. It was given to humans for the first time in 1964. However, Ket produces several adverse reactions such as raised intracranial and blood pressures along with seizures, and patients still show low acceptance due to hallucinations. As new volatile and intravenous anesthetic agents with good emergence and favorable side effect profiles were developed, Ket use markedly decreased. In the 1990s, as the ultrashort-acting opioid remifentanil was developed, high dose opioid could be used to reduce surgical stress in highly invasive procedures. However, high dose opioids can produce hyperalgesia and acute tolerance. As Ket can exert anti-hyperalgesic actions, the clinical use of low dose Ket has been reconsidered. Other beneficial effects of Ket such as; analgesia, anti-shock in hemorrhagic and septic insults, anti-inflammatory effects, anti-tumor effects, brain and spinal cord neuroprotection, and bronchodilation, have all been reported. Moreover, this anesthetic agent at low dose has been recently recognized to possess anti-depressive actions. This diverse profile extends Ket far beyond anesthesia practice and the operating room.

NMDA receptor expression during cell transformation process at early stages of liver cancer in rodent models

Hepatocellular carcinoma (HCC) is the most common primary liver cancer, which is not sensitive to radiotherapy and chemotherapy and very often experiences postoperative relapse. In this regard, effective screening of liver cancer is considered as the most important and urgent task. The aim of our study was to determine whether N-methyl-D-aspartate receptor (NMDAR) and, in particular, its subunits, can serve as biomarkers to distinguish the precancerous liver at early stages of liver fibrosis. We assessed the development of HCC after 10, 15, and 22 wk using a HCC rat model. The expression of NMDAR subunits was monitored at different stages of HCC by means of immunohistochemistry combined with epifluorescence microscopy imaging, Western blotting, and direct bisulfite sequencing. NMDAR subunits were not found in healthy liver tissues. In contrast, NMDAR subunits, in particular NR1 and NR2B, appeared at the stage of severe liver fibrosis (precancerous liver disease) in rats and were expressed during the development of HCC in rats and mice. Using the direct bisulfite sequencing, we detected that increased expression of NMDAR directly correlated with the demethylation of CpG islands in the promoter region of genes encoding receptor subunits. The obtained results confirmed that NMDAR subunits can serve as new biomarkers of precancerous liver disease, severe fibrosis, and its progression towards HCC.NEW & NOTEWORTHY We have shown NMDAR expression in cell transformation process at early stages of cancer, specifically HCC. The aim of our study was to define the disease stages from precancerous liver disease towards liver cancer progression when NMDAR subunits were expressed/detected. A fibrosis/HCC rat model, immunohistochemistry combined with epifluorescence microscopy imaging, Western blotting was used. The dynamics of appearance of NMDAR subunits, their expression and methylation status during the development of HCC were shown and discussed.

Anesthesia Techniques and Long-Term Oncological Outcomes

Despite advances in cancer treatments, surgery remains one of the most important therapies for solid tumors. Unfortunately, surgery promotes angiogenesis, shedding of cancer cells into the circulation and suppresses anti-tumor immunity. Together this increases the risk of tumor metastasis, accelerated growth of pre-existing micro-metastasis and cancer recurrence. It was theorized that regional anesthesia could influence long-term outcomes after cancer surgery, however new clinical evidence demonstrates that the anesthesia technique has little influence in oncologic outcomes. Several randomized controlled trials are in progress and may provide a better understanding on how volatile and intravenous hypnotics impact cancer progression. The purpose of this review is to summarize the effect of the anesthesia techniques on the immune system and tumor microenvironment (TME) as well as to summarize the clinical evidence of anesthesia techniques on cancer outcomes.

Perioperative pain, analgesics and cancer-related outcomes: where do we stand?

Cancer-related pain is one of the most common and debilitating symptoms among cancer patients. Undertreated cancer-related pain interferes with daily activities and increases morbidity and mortality. While opioids continue to play an essential role in treating moderate to severe cancer-related pain, they are associated with many adverse effects including misuse. While preclinical and retrospective studies have shown a negative association between opioid use and cancer outcomes, randomized control trials demonstrate that opioid use does not influence cancer recurrence. Additionally, analgesics and adjuvants used for perioperatively or chronic pain control are unlikely to improve oncological outcomes. This article focuses on the pharmacological management of cancer-related pain and offers an overview regarding the use of these medications perioperatively and the cancer outcomes.

Ketamine Induces Ferroptosis of Liver Cancer Cells by Targeting lncRNA PVT1/miR-214-3p/GPX4

BACKGROUND

Liver cancer ranks the top four malignant cancer type worldwide, which needs effective and safe treatment. Ferroptosis is a novel form of regulated cell death driven by iron-dependent lipid peroxidation and has been regarded as a promising therapeutic target for cancers. In this work, we aimed to study the effects of anesthetic ketamine on proliferation and ferroptosis of liver cancer.

METHODS

Cell viability and proliferation were detected by cell counting kit 8 (CCK-8), colony formation, and 5-ethynyl-2'-deoxyuridine (EdU) assay. Ferroptosis was determined by levels of Fe2+, lipid reactive oxygen species (ROS), and malondialdehyde (MDA). RNA levels of lncPVT1, miR-214-3p, and glutathione peroxidase 4 (GPX4) were checked by real-time PCR assay. Clinical liver tumor samples were collected to detect the levels of long noncoding RNA lncPVT1, miR-214-3p, and GPX4, and their correlation was evaluated by Pearson comparison test. Luciferase reporter gene assay and RNA pulldown were conducted to determine the binding between lncPVT1, miR-214-3p, and GPX4 3'UTR.

RESULTS

Ketamine significantly suppressed viability and proliferation of liver cancer cells both in vitro and in vivo, as well as stimulated ferroptosis, along with decreased expression of lncPVT1 and GPX4. LncPVT1 directly interacted with miR-214-3p to impede its role as a sponge of GPX4. Depletion of lncPVT1 accelerated the ferroptosis of live cancer cells, whereas miR-214-3p inhibition and GPX4 overexpression reversed this effect. Ketamine-induced cell growth suppression and ferroptosis were also suppressed by miR-214-3p inhibition and GPX4 overexpression.

CONCLUSION

In this work, we determined that ketamine suppressed viability of liver cancer cells and induced ferroptosis and identified the possible regulatory mechanism of lncPVT1/miR-214-3p/GPX4 axis.

The downregulation of NCXs is positively correlated with the prognosis of stage II-IV colon cancer

Purpose

Colon cancer (CC) is a very common gastrointestinal tumor that is prone to invasion and metastasis in the late stage. This study aims to observe the expression of Na⁺/Ca²⁺ exchangers (NCXs) and analyze the correlation between NCXs and the prognosis of CC.

Methods

Specimens of 111 stage II–IV CC patients were collected. We used western blotting, qPCR, and immunohistochemical staining to observe the distributions and expression levels of NCX isoforms (NCX1, NCX2, and NCX3) in CC and distal normal tissues. Cox proportional hazards models were used to assess prognostic factors for patients.

Results

The expression of NCXs in most tumor specimens was lower than that in normal tissues. The NCX expression levels in tumor tissues from the primary tumor, local lymph node metastasis sites, and distant liver metastasis sites were increasingly significantly lower than those in normal tissues. The results of the Kaplan-Meier survival curves showed that the downregulation of any NCX isoform was closely related to the worse prognosis of advanced CC.

Conclusion

NCXs can be used as independent prognostic factors for CC. Our research results are expected to provide new targets for the treatment of CC.

Sevoflurane inhibits the migration, invasion and induces apoptosis by regulating the expression of WNT1 via miR-637 in colorectal cancer

Colorectal cancer (CRC) is a common malignancy. Sevoflurane has been reported to involve in the progression in several cancers. However, the molecular mechanism of sevoflurane in CRC progression remains unclear. Quantitative real-time PCR and western blot was used to detect the expression of miR-637 and WNT1. Cell migration, invasion and apoptosis were detected by transwell assay, flow cytometry or western blot, respectively. The interaction between WNT1 and miR-637 was confirmed by luciferase reporter assay, RNA immunoprecipitation assay and pull-down assay. We found sevoflurane could inhibit cell migration and invasion but induced apoptosis in CRC. Besides, the miR-637 level was decreased in CRC tissues and cells but could be rescued by sevoflurane. MiR-637 overexpression enhanced the anticancer functions of sevoflurane in CRC cells, while miR-637 inhibition showed opposite effects. WNT1 was confirmed to be a target of miR-637 and was inhibited by sevoflurane or miR-637. Importantly, knockdown of WNT1 reversed the carcinogenic effects mediated by miR-637 inhibitor in CRC cells treated with sevoflurane. Collectively, sevoflurane inhibited cell migration, invasion and induced apoptosis by regulating the miR-637/WNT1 axis in colorectal cancer, indicating a novel insight into the effective clinical implication for the anesthetic in CRC treatment.

Ketamine Inhibits Ovarian Cancer Cell Growth by Regulating the lncRNA-PVT1/EZH2/p57 Axis

Ketamine is widely used for cancer pain treatment in clinic, and has been shown to inhibit various tumor cells growth. However, the effect of ketamine on ovarian cancer cells growth and the downstream molecules has not been defined. In the present study, we found that ketamine significantly inhibited the proliferation and survival of six ovarian cancer cell lines. Moreover, ketamine induced ovarian cancer cell cycle arrest, apoptosis, and inhibited colony formation capacity. Since lncRNAs have been identified as key regulators of cancer development, we performed bioinformatics analysis of a GEO dataset and found fourteen significantly altered lncRNAs in ovarian cancer patients. We then investigated the effect of ketamine on these lncRNAs, and found that ketamine regulated the expression of lncRNA PVT1. Mechanistically, ketamine regulated P300-mediated H3K27 acetylation activation in the promoter of PVT1. Our RNA immunoprecipitation experiment indicated that PVT1 bound histone methyltransferase enhancer of zeste homolog 2 (EZH2), and regulated the expression of target gene, including p57, and consequently altered ovarian cancer cell biology. Our study revealed that ketamine could be a potential therapeutic strategy for ovarian cancer patients.

The immunomodulatory effect of ketamine in colorectal cancer surgery: a randomized-controlled trial

PURPOSE

Ketamine's inhibitory action on the N-methyl-D-aspartate receptor and anti-inflammatory effects may provide beneficial immunomodulation in cancer surgery. We investigated the effect of subanesthetic-dose ketamine as an adjunct to desflurane anesthesia on natural killer (NK) cell activity and inflammation in patients undergoing colorectal cancer surgery.

METHODS

A total of 100 patients were randomly assigned to a control or ketamine group. The ketamine group received a bolus of 0.25 mg·kg^-1 ketamine five minutes before the start of surgery, followed by an infusion 0.05 mg·kg^-1·hr^-1 until the end of surgery; the control group received a similar amount of normal saline. We measured NK cell activity and proinflammatory cytokines (interleukin-6 [IL-6] and tumour necrosis factor-α [TNF-α]) before surgery and one, 24, and 48 hr after surgery. C-reactive protein (CRP) was measured before surgery and one, three, and five days after surgery. Carcinoembryonic antigen and cancer recurrence/metastasis were assessed two years after surgery.

RESULTS

The NK cell activity was significantly decreased after surgery in both groups, but the change was not different between groups in the linear mixed model analysis (P = 0.47). Changes in IL-6, TNF-α, CRP, and carcinoembryonic antigen levels were not different between groups (P = 0.27, 0.69, 0.99, and 0.97, respectively). Cancer recurrence within 2 years after surgery was similar between groups (10% vs 8%, P = 0.62).

CONCLUSIONS

Intraoperative low-dose ketamine administration did not convey any favourable impacts on overall postoperative NK cell activity, inflammatory responses, and prognosis in colorectal cancer surgery patients.

TRIAL REGISTRATION

www.clinicaltrial.gov (NCT03273231); registered 6 September 2017.

N-Methyl-D-Aspartate (NMDA) receptor modulators: a patent review (2015-present)

INTRODUCTION

- The NMDA receptor is implicated in various diseases including neurodegenerative, neurodevelopmental and mood disorders. However, only a limited number of clinically approved NMDA receptor modulators are available. Today, apparent NMDA receptor drug development strategies entail 1) exploring the unknown chemical space to identify novel scaffolds; 2) using the clinically available NMDA receptor modulators to expand the therapeutic indication space; 3) and to trace physiological functions of the NMDA receptor.

AREAS COVERED

- The current review reflects on the functional and pharmacological facets of NMDA receptors and the current clinical status quo of NMDA receptor modulators. Patent literature covering 2015 till April 2020 is discussed with emphasis on new indications.

EXPERT OPINION

- Supporting evidence shows that subtype-selective NMDA receptor antagonists show an improved safety profile compared to broad-spectrum channel blockers. Although GluN2B-selective antagonists are by far the most extensively investigated subtype-selective modulators, they have shown only modest clinical efficacy so far. To overcome the limitations that have hampered the clinical development of previous subtype-selective NMDA receptor antagonists, future studies with improved animal models that better reflect human NMDA receptor pathophysiology are warranted. The increased availability of subtype-selective probes will allow target engagement studies and proper dose finding in future clinical trials.

Roles of N-methyl-D-aspartate receptors and D-amino acids in cancer cell viability

N-methyl-D-aspartate (NMDA) receptors, which are widely present in the central nervous system, have also been found to be up-regulated in a variety of cancer cells and tumors and they can play active roles in cancer cell growth regulation. NMDA receptor antagonists have been found to affect cancer cell viability and interfere with tumor growth. Moreover, cancer cells also have been shown to have elevated levels of some D-amino acids. Two human skin cell lines: Hs 895.T skin cancer and Hs 895.Sk skin normal cells were investigated. They were derived from the same patient to provide tumor and normal counterparts for comparative studies. The expression of specific NMDA receptors was confirmed for the first time in both skin cell lines. Dizocilpine (MK-801) and memantine, NMDA receptor channel blockers, were found to inhibit the growth of human skin cells by reducing or stopping NMDA receptor activity. Addition of D-Ser, D-Ala, or D-Asp, however, significantly reversed the antiproliferative effect on the human skin cells triggered by MK-801 or memantine. Even more interesting was the finding that the specific intracellular composition of a few relatively uncommon amino acids was selectively elevated in skin cancer cells when exposed to MK-801. It appears that a few specific and upregulated D-amino acids can reverse the drug-induced antiproliferative effect in skin cancer cells via the reactivation of NMDA receptors. This study provides a possible innovative anticancer therapy by acting on the D-amino acid pathway in cancer cells either blocking or activating their regulatory enzymes.

Effects of Anesthesia on Postoperative Recurrence and Metastasis of Malignant Tumors

It is difficult to control the recurrence and metastasis of malignant tumors; furthermore, anesthesia is considered one of the main influencing factors. There has been increasing clinical attention on the effects of anesthetic drugs and methods on postoperative tumor growth and metastasis. We reviewed the effects of anesthesia on tumor recurrence and metastasis; specifically, the effects of anesthetic agents, anesthesia methods, and related factors during the perioperative period on the tumor growth and metastasis were analyzed. This study can provide reference standards for rational anesthesia formulations and cancer-related pain analgesia protocols for surgical procedures in patients with malignant tumors. Moreover, it contributes toward an experimental basis for the improvement and development of novel anesthetic agents and methods.

Glutamate receptor, ionotropic, N-methyl D-aspartate-associated protein 1, a potential target of miR-296, facilitates proliferation and migration of rectal cancer cells

The purpose of our article was to probe the influence of GRINA on rectal cancer and how GRINA is regulated in rectal cancer. Based on the public data, we found that GRINA was highly expressed in rectal cancer tissues and related to worse prognosis in rectal cancer patients. MiR-296 was predicted as an upstream regulatory miRNA of GRINA, which was further verified by dual-luciferase reporter assay. Moreover, we revealed that up-regulation/down-regulation of GRINA facilitated/suppressed SW1463/SW837 cell proliferation, migration, and invasion. Rescue assays indicated that the facilitating impact of GRINA on SW1463 cell proliferation and motility was abolished by miR-296 over-expression whilst the suppressing influence of GRINA on SW837 cell proliferation, migration, and invasion was reversed by miR-296 depletion. These consequences indicated that GRINA, which might be regulated by miR-296, acted stimulative important impact on rectal cancer cells, insinuating that GRINA might be a novel potential target for rectal cancer therapy.

CCL2-CCR2 Axis Potentiates NMDA Receptor Signaling to Aggravate Neuropathic Pain Induced by Brachial Plexus Avulsion

Brachial plexus avulsion (BPA) represents the most devastating nerve injury in the upper extremity and is always considered as a sophisticated problem due to its resistance to most standard pain relief medications or neurosurgical interventions. There is also a lack of understanding on the underlying mechanisms. Our study aimed to investigate whether spinal CCL2-CCR2 signaling contributed to the development of neuropathic pain following BPA via modulating glutamate N-methyl-d-aspartate receptor (NMDAR). A rat model of BPA on lower trunk (C8-T1) was established, and the sham- and BPA-operated animals were intrathecally injected with saline, C-C chemokine receptor type 2 (CCR2) inhibitor INCB3344 and NMDAR antagonist DL-AP5 one week postoperatively, the behavioral performance of the treated animals and expressions of C-C motif ligand 2 (CCL2), CCR2, and N-methyl-D-aspartic acid receptor 2B (NR2B) in spinal cord sections of each group were examined. It was shown that BPA injury significantly reduced mechanic withdrawal thresholds the next day after surgery until the end of the observation. Both CCL2 and CCR2 expressions increased in BPA rats compared to those in sham rats. CCL2 was mainly localized in astrocytes, and CCR2 was preferably expressed on astrocytes and neurons. Besides, NMDAR subunit NR2B increased in BPA-operated rats, which was reversed in response to CCR2 and NR2B inhibition. However, these inhibitors didn't change the spinal NMDAR level in sham rats. CCR2 and NMDAR inhibition efficiently alleviated mechanical allodynia caused by BPA either at early or late phase of neuropathic pain. Collectively, CCL2-CCR2 axis is associated with mechanical pain after BPA by elevating NMDAR signaling.

Propofol attenuates the adhesion of tumor and endothelial cells through inhibiting glycolysis in human umbilical vein endothelial cells

Propofol is one of the most commonly used intravenous anesthetics and plays an important role in tumor suppression. In the present study, we aimed to investigate the mechanism by which propofol attenuates tumor endothelial cells (TECs) and tumor cell adhesion to inhibit tumor metastasis in vitro. Human umbilical vein endothelial cells (HUVECs) cultured in Dulbecco's modified Eagle's medium were treated with tumor conditioned medium for 24 h, followed by 4 h of treatment with or without 25 μM of propofol, 10 μM of KN93, 500 μM of MK801, or 20 μM of rapastinel. It was found that propofol inhibited TEC adhesion and the glycolysis level of TECs. Consistently, propofol inhibited the expressions of adhesion molecules (E-selectin, ICAM-1, and VCAM-1) and glycolysis proteins (GLUT1, HK2, and LDHA) in TECs. Moreover, propofol attenuated the expression of HIF-1α, the phosphorylation of AKT and Ca2+/calmodulin-dependent protein kinase II (CaMKII), and the Ca2+ concentration in TECs. MK801, an inhibitor of NMDA receptor, and KN93, an inhibitor of CaMKII, both inhibited the expressions of adhesion molecules and glycolysis proteins, in a manner similar to propofol. Additionally, rapastine, an activator of NMDA receptor, could counteract the effects of propofol. Our results indicated that propofol attenuates intracellular Ca2+ concentration, CaMKII and AKT phosphorylation, and HIF-1α expression, probably via inhibiting the NMDA receptor, thus inhibiting glycolysis and adhesion of tumor and endothelial cells.