Morphine promotes non-small cell lung cancer progression by downregulating E-cadherin via the PI3K/AKT/mTOR pathway.

Morphine has been suggested to affect cancer cell dynamics and decrease survival rates in lung cancer patients at specific doses, but the precise mechanisms poorly understood. In this study, we aimed to investigate the molecular mechanisms by which morphine modulates the malignant characteristics of non-small cell lung cancer. Cell proliferation was assessed via the Cell Counting Kit-8 assay, and cell migration and invasion were examined via wound healing and Transwell assays. We employed immunofluorescence staining to evaluate E-cadherin expression in A549 and Lewis lung cancer (LLC) cell lines and immunohistochemistry to evaluate E-cadherin expression in nude mice tumours. Additionally, the in vivo effects of morphine on lung cancer progression were explored in a xenograft tumour experiments, in which naloxone was used as a morphine antagonist. Western blot analysis was performed to detect E-cadherin, phosphorylated mTOR (p-mTOR), mTOR, phosphorylated AKT (p-AKT), AKT, phosphorylated PI3K (p-PI3K), and PI3K protein levels in A549 and LLC cells as well as in tumour samples. Morphine (10 µM) significantly increased the proliferation of A549 and LLC cells in vitro (p < 0.05). It also enhanced the migratory and invasive capacities of these cell lines (p < 0.01). Mechanistically, morphine treatment (10 µM) led to a reduction in the expression of E-cadherin, and an increase in the phosphorylation of PI3K, AKT, and mTOR in A549 and LLC cells (p < 0.01). Morphine treatment (1.5 mg/kg) also reduced E-cadherin expression in xenograft tumours and promoted tumour growth in vivo (p < 0.05). This effect was reversed by naloxone (0.1 mg/kg). The results demonstrated that morphine stimulates the malignant proliferation of A549 and LLC cell lines and promotes xenograft tumour growth. Perhaps by specifically targeting MOR, morphine triggers a signalling cascade that activates the PI3K/AKT/mTOR pathway while inhibiting the EMT marker E-cadherin, which may consequently promote the progression of lung cancer.

Postoperative infusion of dexmedetomidine via intravenous patient-controlled analgesia for prevention of postoperative delirium in elderly patients undergoing surgery.

BACKGROUND: Postoperative delirium (POD) is a common clinical complication in elderly patients after surgery and predicts poor outcomes. AIM: We researched whether postoperative infusion of dexmedetomidine (DEX) had prophylactic effect on POD in elderly patients. METHODS: A total of 236 patients over the age of 60 years undergoing thoracoabdominal tumor surgery were enrolled in Zhejiang Cancer Hospital from November 2016 to October 2020. The patients were randomly assigned into DEX group (group D) and control group (Group C). DEX was provided via PCIA pump 1-3 days after surgery, which consisted of 3 ug/kg sufentanil and 3 ug/kg DEX in group D, and 3 ug/kg sufentanil without DEX in group C. The PCIA parameters were programmed as follows: total amount 150 ml, 2 ml bolus dose with a lock-out of 10 min and background infusion rate 2 ml/h. The primary endpoint was the incidence of POD, assessed twice daily within 7 days after surgery by Richmond Agitation-Sedation Scale (RASS) and the Confusion Assessment Method-Intensive Care Unit (CAM-ICU). The secondary endpoint was postoperative hospitalization days, ICU stay time, adverse events and non-delirium complications. RESULTS: The incidence of POD in all patients was 7%. The incidence of POD in group C was significantly higher than that in group D (10.1% vs 3.4%, P = 0.042). There were no significant differences in length of hospital stay after operation, ICU stay time, the percentage of patients discharged within 7 days after surgery, non-delirium complications, and 30-day all-cause deaths between the two groups. The incidence of hypertension in group D was lower than that in group C (P = 0.003), and there were no differences in other adverse events. CONCLUSION: Patients aged over 60 years received DEX in addition to intravenous patient-controlled analgesia (PCIA) for major thoracoabdominal surgery experienced less delirium.

Pre-treatment with morphine prevents lipopolysaccharide-induced acute respiratory distress syndrome in rats via activation of opioid receptors.

PURPOSE: Acute respiratory distress syndrome (ARDS), a severe medical condition, is among the major causes of death in critically ill patients. Morphine is used as a therapeutic agent against severe pain. The mechanisms of its reactions over ARDS are not fully understood. The aim of this study was to assess the mechanism of morphine in rats with ARDS. METHODS: Rats were injected with lipopolysaccharide to induce ARDS, and some rats were pre-treated with graded doses of morphine in the lateral ventricles to assess survival and non-infected mortality. Immunohistochemical and HE staining were performed to measure MPO and CD68 activity in the lungs and lung injury. ELISA was conducted to detect the inflammatory factor levels in the plasma and BALF. Co-labeling of µ-opioid receptor (MOR) and c-Fos was observed in the brain tissues. MOR-positive cells in brain tissues were evaluated using immunohistochemistry. The effect of MOR antagonists on ARDS was examined in rats by pre-injection of naloxone or methylnaltrexone. The expression of MyD88, TLR4, and NF-κB was lastly assessed. RESULTS: Dose-independent improvement was observed in respiratory capacity and lung injury in ARDS rats after morphine pre-injection, along with reduced inflammatory factors in the plasma and BALF. MOR-positive cells were elevated after morphine, which occurred within the ventral part of the gigantocellular reticular nucleus (GiV). Naloxone and methylnaltrexone blocked the effects of morphine via central and peripheral MOR. Morphine activated TLR pathway in a MyD88-dependent manner. CONCLUSION: Morphine activates MOR within the GiV and the TLR pathway to attenuate ARDS in rats.

Comparison of Pain in Male Drug Rehabilitees with and without Human Immunodeficiency Virus in Yunnan Province, China.

BACKGROUND The purpose of this study was to compare pain symptoms in drug rehabilitees with or without human immunodeficiency virus (HIV) in Yunnan Province, China. MATERIAL AND METHODS This was a retrospective single-center cohort study. A total of 120 male substance users, including 65 with HIV, were enrolled after admission to the Fifth Drug Rehabilitation Center in Yunnan Province. Individuals who were >18 years of age and who had illicit drugs detected in their urine, despite not having used drugs for at least 2 months, were included. The patients evaluated their average pain intensity for the previous 4 weeks using a visual analog scale. PainDETECT questionnaire scores were used to classify pain into nociceptive and mixed component subgroups. Sleep quality was also evaluated using the Pittsburgh Sleep Quality Index scale. RESULTS The prevalence and intensity of the pain symptoms were higher for the drug rehabilitees with HIV than for those without HIV. Moreover, the rehabilitees with HIV were more likely to experience neuropathic and nociceptive pain, whereas those without HIV reported only nociceptive pain. The sleep quality of the rehabilitees with HIV was also lower, regardless of the pain symptoms. CONCLUSIONS Our results showed that the drug rehabilitees with HIV in Yunnan Province, China, experienced more frequent and stronger pain (both nociceptive and neuropathic) than those without HIV. They also experienced poorer sleep quality, although it was unrelated to pain. Our results provide data to support clinical diagnosis and treatment.

Comparison of Remimazolam-Flumazenil versus Propofol for Rigid Bronchoscopy: A Prospective Randomized Controlled Trial.

Background: Remimazolam is a novel ultrashort-acting intravenous benzodiazepine sedative−hypnotic that significantly reduces the times to sedation onset and recovery. This trial was conducted to confirm the recovery time from anesthesia of remimazolam-flumazenil versus propofol in patients undergoing endotracheal surgery under rigid bronchoscopy. Methods: Patients undergoing endotracheal tumor resection or stent implantation were randomly allocated into a remimazolam group (Group R) or a propofol group (Group P). The primary outcome was the recovery time from general anesthesia. The secondary outcomes were the time to loss of consciousness (LoC), hemodynamic fluctuations, and adverse events. Results: A total of 34 patients were screened, and 30 patients were enrolled in the study. The recovery time was significantly shorter for Group R (140 ± 52 s) than for Group P (374 ± 195 s) (p < 0.001). The times to LoC were 76 ± 40 s in Group R and 75 ± 25 s in Group P and were not significantly different. There were also no significant differences in hemodynamic fluctuations or adverse events between the two groups. Conclusions: The recovery time from general anesthesia in rigid bronchoscopy patients was shorter using remimazolam-flumazenil than with propofol, with no dramatic hemodynamic fluctuations and adverse events or differences between the agents. Remimazolam-flumazenil allows for faster recovery from anesthesia than propofol.

Antinociceptive effects of macrophage-derived extracellular vesicles by carrying microRNA-216a.

Cancer-induced bone pain (CIBP) represents the pain induced by bone metastases from malignancies. The role of extracellular vesicles (Evs) has been underscored in bone metastasis. However, the function of Evs, especially these derived from M2 macrophages (M2φ-Evs) in CIBP is unclear. Therefore, this investigation aimed to probe the possible antinociceptive effect of M2φ-Evs in CIBP and the underlying mechanism of action. Using the C57bl/6 mice, a CIBP animal model was established by the administration of Walker 256 mammary gland carcinoma cells, followed by M2φ-Evs administration. It was found that CIBP mice treated with M2φ-Evs had significantly reduced nociception and serum inflammatory factors. Microarray sequencing revealed that microRNA-216a (miR-216a) was the most upregulated miRNA in Evs-treated mouse spinal cord tissues. Subsequent bioinformatics, GSEA and KEGG enrichment analyses demonstrated that HMGB1 and TLR4-NF-κB pathway were the downstream effectors of miR-216a and were both downregulated in spinal cord tissues of CIBP mice treated with M2φ-Evs. Rescue experiments displayed that after we reduced miR-216a expression in M2φ-Evs, the antinociceptive effect of M2φ-Evs on CIBP mice was inhibited, and the HMGB1 expression and the TLR4-NF-κB signaling were significantly activated. Together, M2φ-Evs relieve CIBP by carrying miR-216a, which was elicited through the HMGB1/TLR4-NF-κB axis.

Transgenic increase in the ß-endorphin concentration in cerebrospinal fluid alleviates morphine-primed relapse behavior through the µ opioid receptor in rats.

BACKGROUND: Opioid-primed relapse is a global burden. Although current strategies have improved, optimal therapy is urgently needed. METHODS: A recombinant adenovirus (Ad-NEP) expressing ß-endorphin (ß-EP) was designed and injected intracerebroventricularly (icv) into the right lateral ventricle in rats. Spatial and temporal ß-EP expression in the lateral ventricle wall, subventricular zone and adjacent choroid plexus and the ß-EP concentration in the cerebrospinal fluid (CSF) were observed during a 21-day period. A morphine priming-induced conditioned place preference (CPP) rat model was established. The ß-EP-ir neuron counts, CSF ß-EP concentration, and CPP score, which were used to evaluate morphine-primed reinstatement following extinction, were recorded 7 days after the icv injection. Additionally, the rats were pretreated with the irreversible µ opioid receptor antagonist ß-funaltrexamine (ß-FNA) and the selective κ opioid receptor antagonist nor-binaltorphimine (nor-BNI) to identify the receptor-dependent mechanism. RESULTS: Both peak ß-EP expression in target neurons and the peak CSF ß-EP concentration occurred 7 to 8 days after Ad-NEP icv injection. The sustainable increase in the CSF ß-EP concentration was correlated with a decrease in the CPP score 7 days after the Ad-NEP icv injection. Furthermore, reinstatement was almost reversed by ß-FNA pretreatment 24 hours before the behavioral test, but nor-BNI had little effect. CONCLUSION: The increasing cerebrospinal fluid ß-endorphin concentrations showed that the therapeutic effect on opioid relapse occurred predominantly through a µ opioid receptor-dependent mechanism. The Ad-NEP adenovirus can be considered an alternative therapy for opioid relapse.

Inducible Lentivirus-Mediated siRNA against TLR4 Reduces Nociception in a Rat Model of Bone Cancer Pain.

Although bone cancer pain is still not fully understood by scientists and clinicians alike, studies suggest that toll like receptor 4 (TLR4) plays an important role in the initiation and/or maintenance of pathological pain state in bone cancer pain. A promising treatment for bone cancer pain is the downregulation of TLR4 by RNA interference; however, naked siRNA (small interference RNA) is not effective in long-term treatments. In order to concoct a viable prolonged treatment for bone cancer pain, an inducible lentivirus LvOn-siTLR4 (tetracycline inducible lentivirus carrying siRNA targeting TLR4) was prepared and the antinociception effects were observed in bone cancer pain rats induced by Walker 256 cells injection in left leg. Results showed that LvOn-siTLR4 intrathecal injection with doxycycline (Dox) oral administration effectively reduced the nociception induced by Walker 256 cells while inhibiting the mRNA and protein expression of TLR4. Proinflammatory cytokines as TNF-α and IL-1ß in spinal cord were also decreased. These findings suggest that TLR4 could be a target for bone cancer pain treatment and tetracycline inducible lentivirus LvOn-siTLR4 represents a new potential option for long-term treatment of bone cancer pain.

Median effective effect-site concentration of sufentanil for wake-up test in adolescents undergoing surgery: a randomized trial.

BACKGROUND: To determine the median effective concentration of sufentanil as an analgesic during wake-up tests after sevoflurane anesthesia during surgery for adolescent idiopathic scoliosis (AIS). METHODS: This is a randomised controlled trial. Sixty patients aged 13-18 years scheduled for AIS surgery were randomized into six groups of 10 patients each to receive target effect-site concentrations of sufentanil of 0.19, 0.1809, 0.1723, 0.1641, 0.1563, and 0.1489 ng/ml (target concentration ratio, 1.05). Wake-up time was recorded. Median EC50 and 95% confidence interval (CI) for sufentanil target-controlled infusion (TCI) were determined using Kärber's method. The primary outcome was median EC50 for sufentanil TCI as an analgesic during the wake-up test after sevoflurane anesthesia during surgery for AIS. RESULTS: The EC50 and 95% CI of sufentanil TCI were 0.1682 ng/ml and 0.1641 ~ 0.1724 ng/ml, respectively. CONCLUSIONS: The EC50 of sufentanil TCI was 0.1682 ng/ml (95% CI: 0.1641 ~ 0.1724 ng/ml) during sevoflurane anesthesia in adolescents undergoing surgery for idiopathic scoliosis with intraoperative wake-up tests. TRIAL REGISTRATION: Clinicaltrials.gov identifier: ChiCTR-TTRCC-12002696.

Acute PAR2 activation reduces GABAergic inhibition in the spinal dorsal horn.

We investigated the mechanism underlying inhibition of spinal dorsal horn GABAergic neurotransmission to elucidate the role of protease-activated receptor-2 (PAR2). Initially, we confirmed that PAR2 agonist SL-NH(2) applied intrathecally produced mechanical hyperalgesia. Then we performed patch-clamp experiments in substantia gelatinosa neurons of spinal cord slice, and found that spontaneous inhibitory post-synaptic currents (sIPSCs) were significantly decreased in both frequency and amplitude when neurons were incubated with PAR2 agonist SL-NH(2) for a brief time period (2 min). The GABA-mediated currents were significantly reduced, and there was no impact on glycine-mediated currents during this SL-NH(2) treatment. These results suggest that PAR2 activation enhanced the pain response, potentially via inhibition of dorsal horn GABAergic neurotransmission.

Bilateral downregulation of Nav1.8 in dorsal root ganglia of rats with bone cancer pain induced by inoculation with Walker 256 breast tumor cells.

BACKGROUND: Rapid and effective treatment of cancer-induced bone pain remains a clinical challenge and patients with bone metastasis are more likely to experience severe pain. The voltage-gated sodium channel Nav1.8 plays a critical role in many aspects of nociceptor function. Therefore, we characterized a rat model of cancer pain and investigated the potential role of Nav1.8. METHODS: Adult female Wistar rats were used for the study. Cancer pain was induced by inoculation of Walker 256 breast carcinosarcoma cells into the tibia. After surgery, mechanical and thermal hyperalgesia and ambulation scores were evaluated to identify pain-related behavior. We used real-time RT-PCR to determine Nav1.8 mRNA expression in bilateral L4/L5 dorsal root ganglia (DRG) at 16-19 days after surgery. Western blotting and immunofluorescence were used to compare the expression and distribution of Nav1.8 in L4/L5 DRG between tumor-bearing and sham rats. Antisense oligodeoxynucleotides (ODNs) against Nav1.8 were administered intrathecally at 14-16 days after surgery to knock down Nav1.8 protein expression and changes in pain-related behavior were observed. RESULTS: Tumor-bearing rats exhibited mechanical hyperalgesia and ambulatory-evoked pain from day 7 after inoculation of Walker 256 cells. In the advanced stage of cancer pain (days 16-19 after surgery), normalized Nav1.8 mRNA levels assessed by real-time RT-PCR were significantly lower in ipsilateral L4/L5 DRG of tumor-bearing rats compared with the sham group. Western-blot showed that the total expression of Nav1.8 protein significantly decreased bilaterally in DRG of tumor-bearing rats. Furthermore, as revealed by immunofluorescence, only the expression of Nav1.8 protein in small neurons down regulated significantly in bilateral DRG of cancer pain rats. After administration of antisense ODNs against Nav1.8, Nav1.8 protein expression decreased significantly and tumor-bearing rats showed alleviated mechanical hyperalgesia and ambulatory-evoked pain. CONCLUSIONS: These findings suggest that Nav1.8 plays a role in the development and maintenance of bone cancer pain.