Association between intraoperative dexmedetomidine and all-cause mortality and recurrence after laparoscopic resection of colorectal cancer: Follow-up analysis of a previous randomized controlled trial

Dexmedetomidine alleviates the pro-tumor activity of perioperative stress in tumor-bearing mice: an alternative approach of psycho-physiological intervention

BACKGROUND

The immediate perioperative period (IPP) usually is highly stressful and has significant effects on the postoperative recurrence/metastasis of tumors. Effective methods for limiting the impact of the IPP on postoperative recurrence/metastasis of tumors remain scarce. We aimed to determine the effects of dexmedetomidine (DEX) treatment during the IPP on postoperative recurrence/metastasis of tumors and the stress response.

MATERIALS AND METHODS

The clinical perioperative setting was mimicked via tumor resection and perioperative restraint stress in tumor-bearing mice with or without DEX during the IPP. The stress response was assessed using stress hormone and interleukin (IL)-6 levels in peripheral blood. Tumor cell growth was measured via in vivo bioluminescent imaging, cell viability assay, wound-healing assay, and Western blotting.

RESULTS

In tumor-bearing mice, DEX during the IPP limited the growth of implanted tumor cells and stress response in a dose-dependent manner. The serum from mice without DEX promoted cultured tumor cell growth, which was alleviated by beta-adrenergic receptor blocker propranolol or IL-6 antibody. Relative to the serum from mice without DEX, the serum from mice with DEX had lower stress hormone and IL-6 levels, as well as weaker effects on tumor growth promotion. Dexmedetomidine supplementation during culture had no significant effects on tumor cells.

CONCLUSIONS

Dexmedetomidine alleviates the pro-tumor activity of perioperative stress in abdominal tumors.

Dexmedetomidine promotes colorectal cancer progression via Piwil2 signaling

PURPOSE

α2-adrenoceptor agonist dexmedetomidine (DEX) has been reported to promote tumorigenesis. Stem-cell protein Piwil2 is associated with cancer progression. Whether Piwil2 plays a role in tumor-promoting effects of DEX is unknown.

METHODS

We examined the expression of Piwil2 in human colorectal cancer (CRC) cell lines with/without DEX treatment. We also studied the roles of Piwil2 in proliferation, invasion, migration, as well as expressions of epithelial-mesenchymal transition (EMT)-related proteins in DEX-treated in vitro and in vivo CRC models. And the experiments with genetic and pharmacological treatments were conducted to investigate the underlying molecular mechanism.

RESULTS

RNA-sequencing (RNA-seq) analysis found Piwil2 is one of most upregulated genes upon DEX treatment in CRC cells. Furthermore, Piwil2 protein levels significantly increased in DEX-treated CRC cancer cells, which promoted proliferation, invasion, and migration in both CRC cell lines and human tumor xenografts model. Mechanistically, DEX increased nuclear factor E2-related factor 2 (Nrf2) expression, which enhanced Piwil2 transcription via binding to its promoter. Furthermore, in vitro experiments with Piwil2 knockdown or Siah2 inhibition indicated that DEX promoted EMT process and tumorigenesis through Siah2/PHD3/HIF1α pathway. The experiments with another α2-adrenoceptor agonist Brimonidine and antagonists yohimbine and atipamezole also suggested the role of Piwil2 signaling in tumor-promoting effects via an α2 adrenoceptor-dependent manner.

CONCLUSION

DEX promotes CRC progression may via activating α2 adrenoceptor-dependent Nrf2/Piwil2/Siah2 pathway and thus EMT process. Our work provides a novel insight into the mechanism underlying tumor-promoting effects of α2-adrenoceptor agonists.