Pretreatment with interferon-alpha2a modulates perioperative immunodysfunction in patients with renal cell carcinoma

Immunotherapy during the Immediate Perioperative Period: A Promising Approach against Metastatic Disease

Tumor excision is a necessary life-saving procedure in most solid cancers. However, surgery and the days before and following it, known as the immediate perioperative period (IPP), entail numerous prometastatic processes, including the suppression of antimetastatic immunity and direct stimulation of minimal residual disease (MRD). Thus, the IPP is pivotal in determining long-term cancer outcomes, presenting a short window of opportunity to circumvent perioperative risk factors by employing several therapeutic approaches, including immunotherapy. Nevertheless, immunotherapy is rarely examined or implemented during this short timeframe, due to both established and hypothetical contraindications to surgery. Herein, we analyze how various aspects of the IPP promote immunosuppression and progression of MRD, and how potential IPP application of immunotherapy may interact with these deleterious processes. We discuss the feasibility and safety of different immunotherapies during the IPP with a focus on the latest approaches of immune checkpoint inhibition. Last, we address the few past and ongoing clinical trials that exploit the IPP timeframe for anticancer immunotherapy. Accordingly, we suggest that several specific immunotherapies can be safely and successfully applied during the IPP, alone or with supporting interventions, which may improve patients' resistance to MRD and overall survival.

Harnessing cancer immunotherapy during the unexploited immediate perioperative period

The immediate perioperative period (days before and after surgery) is hypothesized to be crucial in determining long-term cancer outcomes: during this short period, numerous factors, including excess stress and inflammatory responses, tumour-cell shedding and pro-angiogenic and/or growth factors, might facilitate the progression of pre-existing micrometastases and the initiation of new metastases, while simultaneously jeopardizing immune control over residual malignant cells. Thus, application of anticancer immunotherapy during this critical time frame could potentially improve patient outcomes. Nevertheless, this strategy has rarely been implemented to date. In this Perspective, we discuss apparent contraindications for the perioperative use of cancer immunotherapy, suggest safe immunotherapeutic and other anti-metastatic approaches during this important time frame and specify desired characteristics of such interventions. These characteristics include a rapid onset of immune activation, avoidance of tumour-promoting effects, no or minimal increase in surgical risk, resilience to stress-related factors and minimal induction of stress responses. Pharmacological control of excess perioperative stress-inflammatory responses has been shown to be clinically feasible and could potentially be combined with immune stimulation to overcome the direct pro-metastatic effects of surgery, prevent immune suppression and enhance immunostimulatory responses. Accordingly, we believe that certain types of immunotherapy, together with interventions to abrogate stress-inflammatory responses, should be evaluated in conjunction with surgery and, for maximal effectiveness, could be initiated before administration of adjuvant therapies. Such strategies might improve the overall success of cancer treatment.

Combining surgery and immunotherapy: turning an immunosuppressive effect into a therapeutic opportunity

Background

Cancer surgery is necessary and life-saving. However, the majority of patients develop postoperative recurrence and metastasis, which are the main causes of cancer-related deaths. The postoperative stress response encompasses a broad set of physiological changes that have evolved to safeguard the host following major tissue trauma. These stress responses, however, intersect with cellular mediators and signaling pathways that contribute to cancer proliferation.

Main

Previous descriptive and emerging mechanistic studies suggest that the surgery-induced prometastatic effect is linked to impairment of both innate and adaptive immunity. Existing studies that combine surgery and immunotherapies have revealed that this combination strategy is not straightforward and patients have experienced both therapeutic benefit and drawbacks. This review will specifically assess the immunological pathways that are disrupted by oncologic surgical stress and provide suggestions for rationally combining cancer surgery with immunotherapies to improve immune and treatment outcomes.

Short conclusion

Given the prevalence of surgery as frontline therapy for solid cancers, the emerging data on postoperative immunosuppression and the rapid development of immunotherapy for oncologic treatment, we believe that future targeted studies of perioperative immunotherapy are warranted.

Research in practice: the impact of interferon-α therapy on immune tolerance

Interferon-α (IFN-α) is the only drug approved for adjuvant therapy of malignant melanoma and is also used in the treatment of hematological and solid tumors. Along with its proven clinical efficacy, IFN-α produces several side effects, particularly with regard to autoimmune disorders. Curious about symptoms of autoimmunity during IFN-α therapy, we asked whether IFN-α directly impacts on immune tolerance. We found that IFN-α does alter the function of tolerogenic dendritic cells (DC) as well as of induced and naturally occurring T-regulatory cells (nTregs). IFN-α blocks the tolerogenic phenotype of DC by inducing maturation and thus preventing the induction of inducible Tregs by DC. It also has direct effects on nTregs. IFN-α reduces cAMP in Tregs via ERK/phosphodiesterase-mediated pathways. Since cAMP is essentially involved in suppression by nTregs, the IFN-α-dependent reduction of cAMP levels abolishes the suppressive capacity of nTregs. Therefore, Tregs are incapable of suppressing the activity of effector T cells and natural killer cells, resulting in tumor rejection. Thus, IFN-α overcomes immunological tolerance processes, leading to an improved immunostimulation and efficient tumor rejection, but also increases the risk of autoimmunity.

Interferon-α suppresses cAMP to disarm human regulatory T cells

IFN-α is an antineoplastic agent in the treatment of several solid and hematologic malignancies that exerts strong immune- and autoimmune-stimulating activity. However, the mechanisms of immune activation by IFN-α remain incompletely understood, particularly with regard to CD4(+)CD25(high)Foxp(+) regulatory T cells (Treg). Here, we show that IFN-α deactivates the suppressive function of human Treg by downregulating their intracellular cAMP level. IFN-α-mediated Treg inactivation increased CD4(+) effector T-cell activation and natural killer cell tumor cytotoxicity. Mechanistically, repression of cAMP in Treg was caused by IFN-α-induced MAP-ERK kinase (MEK)/extracellular signal-regulated kinase (ERK)-mediated phosphodiesterase 4 (PDE4) activation and accompanied by downregulation of IFN receptor (IFNAR)-2 and negative regulation of T-cell receptor signaling. IFN-α did not affect the anergic state, cytokine production, Foxp3 expression, or methylation state of the Treg-specific demethylated region (TSDR) within the FOXP3 locus associated with a stable imprinted phenotype of human Treg. Abrogated protection by IFN-α-treated Treg in a humanized mouse model of xenogeneic graft-versus-host disease confirmed IFN-α-dependent regulation of Treg activity in vivo. Collectively, the present study unravels Treg inactivation as a novel IFN-α activity that provides a conceivable explanation for the immune-promoting effect and induction of autoimmunity by IFN-α treatment in patients with cancer and suggests IFN-α for concomitant Treg blockade in the context of therapeutic vaccination against tumor antigens.