Previously we reported the development of two novel technologies, chemotoxin and chemoarp. Both strategies are based on the nature of chemokines to deliver antigens to the cytosol of cells expressing respective chemokine receptors. 1) The technology designated chemotoxin, a chimeric chemokine fused with toxic moieties, specifically kills cells expressing respective chemokine receptors. For example, using TARC-chemotoxin we could eradicate established leukemia in mice. The technology was used to publish several papers from our laboratory (Baatar et al, 2007a;2009;Olkhanud et al., 2009). However, despite its attractiveness, the major deficiency of the technology is that its immunogenicity. We think that the technology can be effective for treatment of human T-cell and B-cell malignant diseases when patient's immune system is severely immunocompromised. For example, although there are no effective treatments to combat multiple myeloma (MM), we hypothesized that a CXCR5-targeting chemotoxin will provide clinical benefit as direct killers of MM cells. To date, the construction and production of CXCR5-targeting chemotoxin (BLC-PE38) has been achieved. We are now establishing its purification protocol. 2) We recently reported (Biragyn et al., J. Immunotherapy, 2013) that Chemoarp can specifically deliver siRNA/miRNA into immune cells in vivo. The technology overcomes the major stumbling block of siRNA/miRNA use, i.e. the lack of ways to deliver them into immune cells in vivo. We created chemokines modified to bind siRNA/miRNA by hypothesizing that this will enable us to specifically deliver siRNA/miRNA into immune cells. Indeed, we demonstrate that modified chemokine CCL17 (TARC-arp) efficiently silences expression of genes in immune cells by delivering inhibitory oligonucleotides via their chemokine receptors. In modeling studies using mice with established 4T1.2 breast cancer, we show that IL10 produced by FoxP3+CCR4+ Tregs plays an important role in lung metastasis. As such, TARC-arp-mediated silencing of IL-10 or FoxP3 in CCR4+ regulatory T cells (Tregs) is sufficient to block lung metastasis. Thus, we provide a simple solution that circumvents the problems of RNAi use in vivo, indicating that a disease outcome can be successfully controlled by delivering inhibitory oligonucleotides with chemokines to inactivate a selective subset of immune cells, such as CCR4+ Tregs. Overall, considering the simplicity of our chemoarp technology, chemoarp is a potent therapeutic strategy to modulate immune responses and to improve outcome of diseases by, for example, inactivating Tregs and other disease associated immune cells. Recently, the technology was used to specifically activate B cells in mice with breast cancer by delivering immunostimulatory CpG-ODN (Bodogai et al., 2012). Here, we wanted to use the technology to understand the in the role of immune cell-expressing TLRs in mice with cancers. Utilizing various chemoarps, i.e. targeting different chemokine receptors, we are attempting to activate the cells of interest to understand their role in the initiation of antitumor immune responses. On the other hand, we trying to elucidate the role of miRNA in tBreg activity by delivering their miRNA library into normal B cells. Besides a successful collaboration with Dr. Rivas-Santiago (Mexican Institute of Social Security, Mexico) on the development of chemoattractant-based vaccine for tuberculosis (Cervantes-Villagrana et al., 2013), our chemokine-based vectors and know-hows have been successfully used by two groups headed by professors Markham (JHU), Nishioka and Sone (Japan) to generate malaria vaccine and to alleviate asthma, respectively. The studies resulted in two papers (Luo et al., PlosOne, 2014;Honjo et al., Respir. Investig., 2013).
