Therapy implications of the role of interleukin-2 in cancer

ABSTRACT

Introduction: Despite its apparent failure in cancer therapy, IL-2 still remains fundamental in the activation of antitumor immunity.

Areas covered: The aim of this review is the reinterpretation of the role of IL-2 in anticancer immunity, according to knowledge gained of the cytokine network, by highlighting its importance in inducing T helper-1 (TH1) cell proliferation, natural killer (NK) actHivation and IL-12 secretion. However, its main negative effect is the stimulation of regulatory T cells (Tregs), which in contrast suppresses anticancer immunity.

Expert commentary: Cardiovascular toxicity, which was the main clinical problem at the beginning of IL-2 therapy at high intravenous doses, has almost been completely solved by subcutaneous low-dose IL-2 injection. In order to enhance the anticancer efficacy of IL-2, several strategies have been explored, including chemotherapy and interferon, but up until now no regimen has appeared to be clearly better than IL-2 alone. However, considering the role of immune checkpoints (PD-1 and CTLA-4) in Tregs stimulation, the most effective immunotherapy in the future could be concomitant IL-2 administration, to enhance lymphocyte count, and checkpoint inhibitors, such as anti-PD1 or anti-CTLA-4 monoclonal antibodies, or IL-12, which is also able to counteract IL-2-induced Treg cell generation. Therefore, the time for IL-2 immunotherapy in cancer treatment has finally arrived.

KEYWORDS:

• Cancer immunotherapy
• cytokines
• checkpoint inhibitors
• IL-2 immunotherapy
• IL-12

Acknowledgments

The author sincerely thanks Dr. Monica Raggi (Lab. of Microbiology, San Gerardo Hospital, Monza, Italy) for her support in the translation of the present work.

Declaration of interest

The author has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Additional information

Funding

This paper was not funded.