Targeting polyIC to EGFR over-expressing cells using a dsRNA binding protein domain tethered to EGF

Abstract

Selective delivery of drugs to tumor cells can increase potency and reduce toxicity. In this study, we describe a novel recombinant chimeric protein, dsRBEC, which can bind polyIC and deliver it selectively into EGFR over-expressing tumor cells. dsRBEC, comprises the dsRNA binding domain (dsRBD) of human PKR (hPKR), which serves as the polyIC binding moiety, fused to human EGF (hEGF), the targeting moiety. dsRBEC shows high affinity towards EGFR and triggers ligand-induced endocytosis of the receptor, thus leading to the selective internalization of polyIC into EGFR over-expressing tumor cells. The targeted delivery of polyIC by dsRBEC induced cellular apoptosis and the secretion of IFN-β and other pro-inflammatory cytokines. dsRBEC-delivered polyIC is much more potent than naked polyIC and is expected to reduce the toxicity caused by systemic delivery of polyIC.

My journey from tyrosine phosphorylation inhibitors to targeted immune therapy as strategies to combat cancer

“…Internalization of dsRNA induces the tumor to self-destruct by apoptosis, while activating immune modulatory pathways, leading to cytokine and chemokine induction. In addition to type I IFNs, we have detected RANTES, IP-10, GRO-α, IL-2, TNF-α, and IFN-γ (99,106,107). These molecules generate a "bystander effect" against the tumor: They are cytotoxic against tumor cells that do not themselves overexpress the receptor, boost tumor immunogenicity by increasing the expression of MHC-1 and tumor-specific antigens, and attract immune cells such as T cells and NK cells, which mount an attack against the tumor (100, 106, 108) (Fig.…”

“…We have constructed both chemical and protein-based vectors that bind and carry polyIC to cancer cells that overexpress a membrane-bound receptor, such as the EGFR (Fig. 2) (99,100). PolyIC mimics viral dsRNA to provoke a profound antiviral attack.…”

Hsa_circ_0076305 induces migration-proliferation dichotomy in gastric cancer

“…A previous study demonstrated that EGFR interacts with E-cadherin to promote proliferation by activating the MAPK pathway ( 39 ). Furthermore, patients with tumors bearing specific mutations in EGFR or overexpressing EGFR have a good clinical response to selective EGFR inhibitors ( 22 , 40 , 41 ). However, in a previous study, when the tumor cells developed resistance to the EGFR inhibitor, some cells exhibited mesenchymal characteristics and low EGFR expression, survived and underwent EMT ( 25 ).…”

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“…Previous studies showed that PKR has a high affinity for polyIC [52][53][54] and that isolated dsRBDs can facilitate the delivery of siRNA into cells [55]. Based on these reports we recently used the isolated dsRBDs to deliver polyIC to EGFtargeted cells successfully [56].…”

“…Here, we had the additional complication that the dsRB domain binds host nucleic acids [57]. We designed a purification process incorporating an unfolding and re-folding protocol, SCP-N TTTACTCGAGCGGAGGTGCAGCTGCAGC SCP-C TTTTGCTCAGCGCCGTTACAGGTCC AGCCATG GFP-N TTTTCATATGGTGAGCAAGGGCG GFP-C TAAGGATCCGCCACCGCCGCTTTT CTTGTACAGC dsRB-N TTTCATATGATGGCTGGTGATC dsRB-C TTAGGATCCGCCACCGCCGCTCTCCGATAAGATC TGCAG 9ARG1 GATCCCGTCGTCGCCGTCGTCGCCGTCGCGGCCGCAA 9ARG2 AGCTTTGCGGCCGCGACGGCGACGACGGCGACGACGG Oncotarget 24055 www.impactjournals.com/oncotarget which successfully released the host nucleic acids [56]. We proved that the dsRB domain was functional using a gel mobility shift assay [58] (Figure 2C).…”