Anti-CD20-Interferon-β Fusion Protein Therapy of Murine B-Cell Lymphomas

Abstract

Type I interferons (IFNα/β) are cytokines with a broad spectrum of anti-tumor activities including anti-proliferative, pro-apoptotic, and immunostimulatory effects, and are potentially useful in the treatment of B cell malignancies and other cancers. To improve anti-tumor potency and diminish the systemic side effects of IFN, we recently developed anti-CD20-IFNα fusion proteins with in vitro and in vivo efficacy against both mouse and human lymphomas expressing CD20. Since IFNβ binds more tightly to the IFNα/β receptor (IFNAR) and has more potent anti-tumor activities, we have now constructed an anti-CD20 fusion protein with murine IFNβ (mIFNβ). Anti-CD20-mIFNβ was more potent than recombinant mIFNβ and anti-CD20-mIFNα in inhibiting the proliferation of a mouse B cell lymphoma expressing human CD20 (38C13-huCD20). Growth inhibition was accompanied by caspase-independent apoptosis and DNA fragmentation. The efficacy of anti-CD20-mIFNβ required the physical linkage of mIFNβ to anti-CD20 antibody (Ab). Importantly, anti-CD20-mIFNβ was active against tumor cells expressing low levels of IFNAR (38C13-huCD20 IFNARlo). In vivo, established 38C13-huCD20 tumors were largely insensitive to rituximab or a non-targeted mIFNβ fusion protein, yet treatment with anti-CD20-mIFNβ eradicated 83% of tumors. Anti-CD20-mIFNβ was also more potent in vivo against 38C13-huCD20 than anti-CD20-mIFNα, curing 75% versus 25% of tumors (p = 0.001). Importantly, while anti-CD20-mIFNα could not eradicate 38C13-huCD20 IFNARlo tumors, anti-CD20-mIFNβ treatment prolonged survival (p = 0.0003), and some animals remained tumor-free. Thus, Ab fusion proteins targeting mIFNβ to tumors show promise as therapeutic agents, especially for use against tumors resistant to the effects of mIFNα.

Anti-CD20-interleukin-21 fusokine targets malignant B cells via direct apoptosis and NK-cell–dependent cytotoxicity

“…21,34 Apart from its immunostimulatory effects, IL-21 exerts direct cytotoxicity on a variety of IL-21R-expressing NHLs, including diffuse large B-cell lymphoma (DLBCL), MCL, chronic lymphocytic leukemia, and follicular lymphoma. 32,[35][36][37][38][39][40][41][42] We found that the direct apoptotic effects of IL-21 in DLBCL and MCL were mediated via activation of an IL-21R-dependent signaling pathway that leads to phosphorylation of STATs followed by upregulation of cMyc and Bax and downregulation of BCL-2 and BCL-XL. 32,35 These studies suggest IL-21 may become a potent adjuvant to cancer immunotherapy against B-cell lymphoma.…”

“…In preclinical studies, fusion of type I interferons (IFNa/b) with CD20 mAb demonstrated potent antilymphoma effects in B-cell lymphoma tumor models. 39,40 Fusion of granulocyte-macrophage colony-stimulating factor and IL-21 (GIFT-21) activated immune response and led to antitumor responses in the B16 xenograft model. 41 A recent study of IL-2 fusion with fragment constant (Fc) region (Fc/IL-2) resulted in significant tumor control in isogenic tumor models.…”

Targeted immunotherapy using anti-CD138-interferon α fusion proteins and bortezomib results in synergistic protection against multiple myeloma

“…27,28 Previous studies in our laboratory [8][9][10][11] have shown that genetic fusion of IFNs to an antibody is an effective strategy to specifically target IFN to the tumor microenvironment, reduce systemic toxicity, and increase half-life.…”

“…Our strategy of fusing IFN to antibody has several major advantages in vivo. While the half-life of IFNa is only 1 h, 26 we have shown that fusing it to IgG extends the half-life to 8 h. 10,11 In addition, the anti-CD138 portion of the fusion protein provides a binding specificity to target MM and deliver therapeutically useful levels of IFN without systemic toxicity. Indeed, we have shown the effectiveness of this strategy in targeting not only MM, 8 but also lymphoma using anti-CD20-IFNa2.…”

“…This approach has been used effectively to target IFN to various tumors. [8][9][10][11] To target IFN to MM, we fused it to the B-B4 antibody that specifically binds CD138. 8,12 CD138, also known as syndecan-1, is highly expressed on mature plasma cells, making it a suitable target for MM.…”