Perioperative Stress, Inflammation, and Cancer Progression: Opportunities for Intervention in Breast and Colorectal Cancer Surgery Utilizing Beta-Adrenergic Blockade and COX-2 Inhibition

The multifaceted role of beta-blockers in overcoming cancer progression and drug resistance: Extending beyond cardiovascular disorders

Beta-blockers are commonly used medications that antagonize β-adrenoceptors, reducing sympathetic nervous system activity. Emerging evidence suggests that beta-blockers may also have anticancer effects and help overcome drug resistance in cancer treatment. This review summarizes the contribution of different isoforms of beta-adrenoceptors in cancer progression, the current preclinical and clinical data on associations between beta-blockers use and cancer outcomes, as well as their ability to enhance responses to chemotherapy and other standard therapies. We discuss proposed mechanisms, including effects on angiogenesis, metastasis, cancer stem cells, and apoptotic pathways. Overall, results from epidemiological studies and small clinical trials largely indicate the beneficial effects of beta-blockers on cancer progression and drug resistance. However, larger randomized controlled trials are needed to firmly establish their clinical efficacy and optimal utilization as adjuvant agents in cancer therapy.

Targeting Myeloid-Derived Suppressor Cells for Premetastatic Niche Disruption After Tumor Resection

Surgical resection is a common therapeutic option for primary solid tumors. However, high cancer recurrence and metastatic rates after resection are the main cause of cancer related mortalities. This implies the existence of a "fertile soil" following surgery that facilitates colonization by circulating cancer cells. Myeloid-derived suppressor cells (MDSCs) are essential for premetastatic niche formation, and may persist in distant organs for up to 2 weeks after surgery. These postsurgical persistent lung MDSCs exhibit stronger immunosuppression compared with presurgical MDSCs, suggesting that surgery enhances MDSC function. Surgical stress and trauma trigger the secretion of systemic inflammatory cytokines, which enhance MDSC mobilization and proliferation. Additionally, damage associated molecular patterns (DAMPs) directly activate MDSCs through pattern recognition receptor-mediated signals. Surgery also increases vascular permeability, induces an increase in lysyl oxidase and extracellular matrix remodeling in lungs, that enhances MDSC mobilization. Postsurgical therapies that inhibit the induction of premetastatic niches by MDSCs promote the long-term survival of patients. Cyclooxygenase-2 inhibitors and β-blockade, or their combination, may minimize the impact of surgical stress on MDSCs. Anti-DAMPs and associated inflammatory signaling inhibitors also are potential therapies. Existing therapies under tumor-bearing conditions, such as MDSCs depletion with low-dose chemotherapy or tyrosine kinase inhibitors, MDSCs differentiation using all-trans retinoic acid, and STAT3 inhibition merit clinical evaluation during the perioperative period. In addition, combining low-dose epigenetic drugs with chemokine receptors, reversing immunosuppression through the Enhanced Recovery After Surgery protocol, repairing vascular leakage, or inhibiting extracellular matrix remodeling also may enhance the long-term survival of curative resection patients.

Premetastatic niches, exosomes and circulating tumor cells: Early mechanisms of tumor dissemination and the relation to surgery

The physiological stress response to surgery promotes wound healing and functional recovery and includes the activation of neural, inflammatory and proangiogenic signaling pathways. Paradoxically, the same pathways also promote metastatic spread and growth of residual cancer. Human and animal studies show that cancer surgery can increase survival, migration and proliferation of residual tumor cells. To secure the survival and growth of disseminated tumor cells, the formation of premetastatic niches in target organs involves a complex interplay between microenvironment, immune system, circulating tumor cells, as well as chemical mediators and exosomes secreted by the primary tumor. This review describes the current understanding of the early mechanisms of dissemination, as well as how surgery may facilitate disease progression.