Prevention of liver metastases through perioperative acute CpG-C immune stimulation.

Following excision of colorectal tumors, metastatic disease is prevalent, primarily occurs in the liver, and is highly predictive of poor prognosis. The perioperative period is now recognized as critical in determining the incidence of postoperative metastases and long-term cancer outcomes. Thus, various perioperative prophylactic interventions are currently studied during this time frame. However, immune stimulation during the perioperative period has rarely been attempted due to specific contraindications to surgery and various adverse effects. Here, to prevent liver metastases, we perioperatively employed a TLR-9 agonist, CpG-C, which exhibits minimal pyrogenic and other adverse effects in patients. We found that marginating-hepatic (MH) cells in BALB/c mice contained high percentage of NK cells, but exhibited negligible NK cytotoxicity, as previously reported in humans. However, a single CpG-C administration (25-100 µg/mouse) doubled MH-NK cell numbers, increased NK cell activation and maturation markers (NKp46, CD11b), decreased the inhibitory NKG2A ligand, and dramatically increased MH-NK-cell cytotoxicity against the syngeneic CT26 colon cancer line. Moreover, in operated mice, this innocuous intervention also markedly improved resistance to CT26 and MC38 hepatic metastases in BALB/c and C57BL/6 mice, respectively. Beneficial effects of CpG-C were mediated through activation of MH-NK cells, as indicated by an in vivo NK depletion study. Last, CpG-C protected against surgery-induced suppression of MH-NK cytotoxicity and improved their activation indices. Thus, we suggest that systemic perioperative CpG-C treatment should be considered and studied as a novel therapeutic approach to improve long-term cancer outcomes in colorectal cancer patients.

Perioperative biobehavioral interventions to prevent cancer recurrence through combined inhibition of ß-adrenergic and cyclooxygenase 2 signaling.

Evidence suggests that excess perioperative activation of the sympathetic nervous system and the consequent release of catecholamines (ie, epinephrine and norepinephrine) in the context of cancer surgery and inflammation may significantly facilitate prometastatic processes. This review first presents biomedical processes that make the perioperative timeframe pivotal in determining long-term cancer outcomes nonproportionally to its short duration (days to weeks). Then, it analyzes the various mechanisms via which the excess release of catecholamines can facilitate the progression of cancer metastases in this context by directly affecting the malignant tissues and by regulating, via indirect pathways, immunological and other mechanisms that affect metastatic progression in the tumor microenvironment and systemically. In addition, this review addresses the need to supplement ß-adrenoreceptor blockade with cyclooxygenase 2 inhibition, especially during surgery and shortly thereafter, because similar mechanisms are simultaneously activated by surgery-induced inflammatory responses. Importantly, this review presents translational and clinical evidence showing that perioperative ß-adrenoreceptor blockade and cyclooxygenase 2 inhibition can reduce the prometastatic process and cancer recurrence, and the clinical feasibility and safety of this approach are demonstrated as well. Lastly, alternative psychophysiological approaches to the use of ß-adrenergic blockers are presented because a substantial portion of patients have medical contraindications to this pharmacological treatment. The adaptation of existing psychophysiological interventions to the perioperative period and principles for constructing new approaches are discussed and exemplified. Overall, pharmacobehavioral interventions, separately or in combination, could transform the perioperative timeframe from being a prominent facilitator of metastatic progression to an opportunity for arresting or eliminating residual disease, potentially improving long-term survival rates in cancer patients.