Targeting the mu-Opioid Receptor for Cancer Treatment

Parecoxib inhibits tumorigenesis and angiogenesis in hepatocellular carcinoma through ERK-VEGF/MMPs signaling pathway

Parecoxib, a well-recognized nonsteroidal anti-inflammatory drug, has been reported to possess anticancer properties in various tumor types. In this work, we aimed to investigate the potential anticancer effects of parecoxib on hepatocellular carcinoma (HCC) cells. To assess the impact of parecoxib on HCC cell proliferation, we employed Cell Counting Kit-8, colony formation, and 5-ethynyl-2'-deoxyuridine assays. Hoechst/propidium iodide (PI) double staining and flow cytometry were performed to evaluate apoptosis and cell cycle analysis. Wound healing and transwell assays were utilized to assess cell migration and invasion. Tube formation assay was employed to analyze angiogenesis. Protein levels were determined using western blotting, and mRNA expression levels were assessed using quantitative real-time polymerase chain reaction (PCR). A xenograft mouse model was used to confirm the antitumor effects of parecoxib on HCC tumors in vivo. Our data demonstrated that parecoxib effectively inhibited the proliferation of HCC cells in a dose- and time-dependent manner. In addition, parecoxib induced cell cycle arrest in the G2 phase and promoted apoptosis. Moreover, parecoxib hindered tumor migration and invasion by impeding the epithelial-mesenchymal transition process. Further investigation showed that parecoxib could significantly suppress angiogenesis through the inhibition of extracellular signal-regulated kinase (ERK)-vascular endothelial growth factor (VEGF) axis. Notably, treatment with the ERK activator phorbol myristate acetate upregulated the expression of matrix metalloproteinase (MMP)-2, MMP-9, and VEGF and reversed the function of parecoxib in HCC cells. Besides, parecoxib displayed its antitumor efficacy in vivo. Collectively, our results suggest that parecoxib ameliorates HCC progression by regulating proliferation, cell cycle, apoptosis, migration, invasion, and angiogenesis through the ERK-VEGF/MMPs signaling pathway.

Effects of opioid drugs on immune function in cancer patients

Opioid receptor agonists are often used when cancer patients undergo surgery or analgesic treatment. As analgesics in clinical care, opioids can provide intraoperative or to chronic cancer pain relief. Immune function plays an important role in anti-cancer therapy, with cellular immunity, comprised principally of T-lymphocytes and natural killer cells, representing the primary anti-cancer immune response. However, it remains unclear whether immune function is further affected with the use of opioids in already immunocompromised cancer patients. This article provides a review of the effects of commonly used clinical opioids, including morphine, oxycodone, fentanyl and tramadol, on immune function in cancer patients. It provides a summary of current evidence regarding the immunomodulatory effects of opioids in the cancer setting and mechanisms underlying these interactions.

Effects of tramadol via a µ-opioid receptor on pancreatic ductal adenocarcinoma in vitro and in vivo

INTRODUCTION

Tramadol, a weak opioid anesthetic, is used for pain management in patients with cancer, but the effects of tramadol on cancer via µ-opioid receptor are still unknown. We assessed the effects of tramadol on pancreatic ductal adenocarcinoma using transgenic mice (LSL-KrasG12D/+; Trp53flox/flox; Pdx-1cre/+ ).

METHODS

Six-week-old transgenic mice were orally administered 10 mg/kg/day tramadol (n=12), 10 mg/kg/day tramadol and 1 mg/kg/day naltrexone (n=9), or vehicle water (n=14) until the humane endpoint. Cancer-related pain and plasma cytokine levels were assessed by the mouse grimace scale and cytokine array, respectively. Tumor status was determined histopathologically. Tramadol's effects on proliferation and invasion in pancreatic ductal adenocarcinoma cell lines were studied in vitro.

RESULTS

Tramadol with/without naltrexone improved mouse grimace scale scores while decreasing inflammatory cytokines such as tumor necrosis factor-α and interleukin-6. Proliferative Ki-67 and cyclins decreased by tramadol, while local M1-like tumor-associated macrophages increased by tramadol, which was blocked by naltrexone. Meanwhile, tramadol with/without naltrexone reduced juxta-tumoral cancer-associated fibroblasts and M2-like tumor-associated macrophages. Tumor-associated neutrophils, natural killers, and cytotoxic T cells were not altered. Tramadol decreased the proliferative and invasive potentials of pancreatic ductal adenocarcinoma cell lines via decreasing cyclins/cyclin-dependent kinases, which was partially reversed by naltrexone.

CONCLUSIONS

These findings imply that tramadol might be a useful anesthetic for pancreatic ductal adenocarcinoma: inhibiting the proliferation and invasion along with increasing antitumor M1-like tumor-associated macrophages via the µ-opioid receptor, while improving cancer-associated pain possibly through the antitumor effects with the decrease of inflammatory cytokines.

The Impact of Perioperative Events on Cancer Recurrence and Metastasis in Patients after Radical Gastrectomy: A Review

Radical gastrectomy is a mainstay therapy for patients with locally resectable gastric cancer (GC). GC patients who are candidates for radical gastrectomy will experience at least part of the following perioperative events: surgery, anesthesia, pain, intraoperative blood loss, allogeneic blood transfusion, postoperative complications, and their related anxiety, depression and stress response. Considerable clinical studies have shown that these perioperative events can promote recurrence and decrease the long-term survival of GC patients. The mechanisms include activation of neural signaling and the inflammatory response, suppression of antimetastatic immunity, increased release of cancer cells into circulation, and delayed adjuvant therapy, which are involved in every step of the invasion-metastasis cascade. Having appreciated these perioperative events and their influence on the risk of GC recurrence, we can now use this knowledge to find strategies that might substantially prevent the deleterious recurrence-promoting effects of perioperative events, potentially increasing cancer-free survival in GC patients.

Association of Mu-Opioid Receptor Expression With Long-Term Survival and Perineural Nerve Invasion in Patients Undergoing Surgery for Ovarian Cancer

Background

Opioids are widely used during primary debulking surgery (PDS) for ovarian cancers, and a high mu-opioid receptor (MOR) expression predicts worse cancer outcomes. However, the impact of MOR expression on survival outcomes in ovarian cancers is still not clear.

Methods

A retrospective cohort study was conducted in patients who underwent PDS in ovarian cancer patients. MOR expression was measured in tumor and normal tissue. Primary outcomes were overall survival (OS) and disease-free survival (DFS). Secondary outcomes included perineural invasion (PNI), intraoperative sufentanil consumption, length of stay (LOS), and verbal numerical rating scale (VNRS) on postoperative day 1 (POD1), POD3, and POD5.

Results

After propensity score matching, a total of 366 patients were finally enrolled in this study. There were no significant differences in OS rates in patients with high versus low levels of MOR (1-year OS: 82.9% versus 83.3%, 3-year: 57.8% versus 59.1%, 5-year: 22.4% versus 23.1%,respectively) in the ovarian cancers. There were no significant differences in DFS between the groups. Intraoperative sufentanil consumption was higher in the MOR high-expression group compared with the MOR low-expression group. Tumors expressing high levels of MOR showed higher rates of PNI. VNRS in the MOR high-expression group was higher on POD1.

Conclusion

MOR is not an independent predictor of worse survival in ovarian cancers but is associated with high rates of perineural invasion.