Interleukin-2 enhances the natural killer cell response to Herceptin-coated Her2 /neu-positive breast cancer cells

Abstract

The Her2 / neu (c‐erbB‐2) oncogene encodes a 185‐kDa protein tyrosine kinase which is overexpressed in 20 % of breast adenocarcinomas and is recognized by a humanized anti‐Her2 / neu monoclonal antibody (mAb) (rhu4D5 or Herceptin). Natural killer (NK) cells are capable of mediating antibody‐dependent cell cytotoxicity (ADCC) against antibody‐coated targets via their expression of a low‐affinity receptor for IgG (FcγRIII or CD16). NK cells can be expanded in cancer patients via the administration of low‐dose interleukin‐2 (IL‐2) and become potent cytotoxic effectors following exposure to high doses of IL‐2. We tested IL‐2‐activated NK cells against Her2 / neu+ (MCF‐7Her2 / neu) and Her2 / neu– (MDA‐468) breast cancer cell lines in a 4‐h 51Cr‐release cytotoxicity assay in the presence or absence of rhu4D5 mAb (effector : target ratio = 10 : 1). Specific lysis of rhu4D5‐coated MCF‐7Her2 / neu and MDA‐468 target cells by IL‐2‐activated NK cells was 35 % and 3 %, respectively (p < 0.05). Lysis was less than 5 % when targets were treated with either the non‐humanized mu4D5 mAb or control huIgG. Lysis of rhu4D5‐coated MCF‐7Her2 / neu cells was inhibited by 80 % when NK cells were pre‐treated with an anti‐Fc receptor antibody prior to use in the cytotoxicity assay. Enhanced ADCC of MCF‐7Her2 / neu target cells was seen when the effector cells consisted of mononuclear cells obtained from a patient demonstrating significant expansion of NK cells secondary to therapy with low‐dose IL‐2. Serum from patients receiving infusions of rhu4D5 mAb could substitute for exogenous antibody in the ADCC assay. NK cells activated by rhu4D5‐coated tumor cells in the presence of IL‐2 also produced large amounts of IFN‐γ with concomitant up‐regulation of cell‐surface activation markers CD25 and CD69. These results lend support to the concurrent use of rhu4D5 mAb and IL‐2 therapy in patients with cancers that express the Her2 / neu oncogene.

Targeting the function of the HER2 oncogene in human cancer therapeutics

“…The evidence that trastuzumab works through an ADCC-mediated mechanism has led some investigators to determine whether this activity can be further enhanced by additional immunostimulatory approaches. Consistent with this hypothesis, IL-2 enhances the in vitro ADCC activity of trastuzumab (Carson et al, 2001;Kubo et al, 2003). However, a phase I trial of this combination modality found no evidence of increased clinical activity associated with IL-2-induced NK cell expansion (Repka et al, 2003).…”

“…mAb 4D5 activates ADCC in vitro (Carter et al, 1992;Clynes et al, 2000). This activity was greatly enhanced during the process to engineer the humanized version and trastuzumab is indeed highly efficient at activating ADCC in vitro (Carter et al, 1992;Cooley et al, 1999;Carson et al, 2001;Kubo et al, 2003;Repka et al, 2003). Mouse genetic models that experimentally manipulate Fc receptor function positively or negatively clearly demonstrate the role of host immunologic mechanisms in the antitumor efficacy of these agents.…”

In vitro activity of pertuzumab in combination with trastuzumab in uterine serous papillary adenocarcinoma

“…Natural killer cells are considered to be the best-suited lymphocytes for ADCC because they carry FcgRIII receptors, which are activator molecules, and not FcgRIIb receptors, which inhibit ADCC (Carson et al, 2001). Natural killer cells also carry receptors for IL-2, a cytokine that induces expansion of the NK cell population and enhances their function (Repka et al, 2003).…”

“…Natural killer cells also carry receptors for IL-2, a cytokine that induces expansion of the NK cell population and enhances their function (Repka et al, 2003). Outpatient low-dose IL-2 has, therefore, been previously used to enhance cancer patients' immune response to mAbs with little toxicity (Carson et al, 2001;Repka et al, 2003). Consistent with this, a significant increase in ADCC against USPC was detected after exposure of PBLs from healthy donors to low doses of IL-2 in vitro for a brief time (i.e., 5 h).…”

Adjuvant cellular immunotherapy in patients with resected primary non-small cell lung cancer

“…For expansion of autologous NK cells, PBMCs were cultured in an anti-HER2 monoclonal antibody [47][48][49] (Roche Pharma) coated 75 cm 2 flask with X-VIVO 15 serum-free medium supplemented with 1,000 U/mL IL-2 for 24 h. Next, the cells were centrifuged, and the supernatant was discarded. The cells were cultured again in X-VIVO 15 serum-free medium supplemented with 1,000 U/mL IL-2 for 2 weeks.…”