Dexmedetomidine upregulates the expression of miR-493-5p, inhibiting growth and inducing the apoptosis of lung adenocarcinoma cells by targeting RASL11B

Trial watch: dexmedetomidine in cancer therapy

Dexmedetomidine (DEX) is a highly selective α2-adrenoceptor agonist that is widely used in intensive and anesthetic care for its sedative and anxiolytic properties. DEX has the capacity to alleviate inflammatory pain while limiting immunosuppressive glucocorticoid stress during major surgery, thus harboring therapeutic benefits for oncological procedures. Recently, the molecular mechanisms of DEX-mediated anticancer effects have been partially deciphered. Together with additional preclinical data, these mechanistic insights support the hypothesis that DEX-induced therapeutic benefits are mediated via the stimulation of adaptive anti-tumor immune responses. Similarly, published clinical trials including ancillary studies described an immunostimulatory role of DEX during the perioperative period of cancer surgery. The impact of DEX on long-term patient survival remains elusive. Nevertheless, DEX-mediated immunostimulation offers an interesting therapeutic option for onco-anesthesia. Our present review comprehensively summarizes data from preclinical and clinical studies as well as from ongoing trials with a distinct focus on the role of DEX in overcoming (tumor microenvironment (TME)-imposed) cancer therapy resistance. The objective of this update is to guide clinicians in their choice toward immunostimulatory onco-anesthetic agents that have the capacity to improve disease outcome.

Dexmedetomidine provides type-specific tumour suppression without tumour-enhancing effects in syngeneic murine models

BACKGROUND

Dexmedetomidine is a widely used anaesthetic adjuvant for cancer resection surgeries. However, recent reports suggest that it may promote tumour growth or metastasis, so it is essential to clarify its tumour-related effects.

METHODS

Seven syngeneic murine tumour models were used to assess the impact of dexmedetomidine on primary tumour growth, spontaneous tumour metastasis, and surgical resection-associated metastasis. Cancer cell proliferation and apoptosis experiments, terminal deoxynucleotidyl transferase dUTP nick-end labelling assays, immune cell analysis, specific T-cell depletion experiments, and gene transcription analysis were conducted to identify the underlying mechanisms.

RESULTS

Dexmedetomidine did not affect growth of EO771 or 4T1 breast tumours, LAP0297 or LLC lung tumours, MCA205 fibrosarcoma, or their spontaneous lung metastases. It did not promote lung metastasis after breast cancer resection. Dexmedetomidine significantly suppressed MCA38 and CT26 colorectal tumour growth (P<0.01) and promoted apoptosis in MCA38 tumour tissues (P<0.05) without affecting proliferation and apoptosis of MCA38 tumour cells in vitro, suggesting indirect anti-tumour effects. Dexmedetomidine increased the proportions of intratumour CD4⁺ T (P<0.01), CD8⁺ T (P<0.001), and natural killer cells (P<0.01), and it upregulated transcription of the cytotoxicity-related genes Infg, Tnfa, and Cxcl9 (P<0.05) in MCA38 tumours. Either CD8⁺ or CD4⁺ T-cell depletion reversed the anti-tumour effects of dexmedetomidine on MCA38 tumours (P<0.05).

CONCLUSIONS

Dexmedetomidine conferred colorectal tumour-type specific suppression by modulation of tumour CD4⁺ and CD8⁺ T cells without tumour-enhancing effects.

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.

Dexmedetomidine disrupts esophagus cancer tumorigenesis by modulating circ_0003340/miR-198/HMGA2 axis

More and more studies have focused on the regulatory role of circular RNAs (circRNAs) in various cancers. However, it is not clear how dexmedetomidine (DEX) affects esophagus cancer progression by affecting the expression of circRNAs. This study aimed to investigate the role of DEX in esophagus cancer and its underlying mechanism. Cell Counting Kit-8 assay and 5-ethynyl-2'-deoxyuridine assays were conducted to evaluate cell proliferation. Flow cytometry analysis and transwell assay were performed for cell apoptosis and invasion. The protein levels of cleaved caspase-3, matrix metallopeptidase 9, and high mobility group AT-hook 2 (HMGA2) were assessed by western blot assay. The expression levels of circ_0003340 and microRNA-198 (miR-198) were determined by quantitative real-time PCR. Dual-luciferase reporter assay was performed to verify the interaction between miR-198 and circ_0003340 or HMGA2. Murine xenograft model was established to investigate the role of circ_0003340 and DEX in vivo. DEX exerted antitumor effects in esophagus cancer cells. DEX hindered proliferation and invasion while inducing apoptosis of esophagus cancer cells, which was abolished by circ_0003340 elevation, HMGA2 overexpression, or miR-198 silencing. miR-198 directly interacted with circ_0003340 and HMGA2 in esophagus cancer cells. Moreover, knockdown of circ_0003340 could improve the anticancer role of DEX in vivo. DEX constrained cell carcinogenesis by regulating circ_0003340/miR-198/HMGA2 axis in esophagus cancer, providing an effective clinical implication for preventing the development of the esophagus cancer by the DEX.