Selective proapoptotic activity of a secreted recombinant antibody/AIF fusion protein in carcinomas overexpressing HER2

Abstract

Apoptosis-inducing factor (AIF) represents a caspase-independent apoptotic pathway in the cell, and a mitochondrial localization sequence-truncated AIF (AIFD1-120) can be relocated from the cytoplasm to the nucleus and exhibit a constitutive proapoptotic activity. Here, we generated a chimeric immuno-AIF protein, which comprised an HER2 antibody, a Pseudomonas exotoxin translocation domain and AIFD1-120. Human Jurkat cells transfected with the immuno-AIF gene could express and secrete the chimeric protein, which selectively recognized HER2-overexpressing tumor cells and was endocytosed. Subsequent cleavage of truncated AIF from immuno-AIF and its release from the internalized vesicles resulted in apoptosis of tumor cells. Intramuscular injection of the immuno-AIF gene caused significant suppression of tumors and substantially prolonged mice survival in an HER2-overexpressing xenograft tumor model. Our study demonstrates the feasibility of the immuno-AIF gene as a novel approach to treating cancers that overexpress HER2. Gene Therapy (2006) 13, 313-320.

BNIP3 (Bcl-2 19 kDa Interacting Protein) Acts as Transcriptional Repressor of Apoptosis-Inducing Factor Expression Preventing Cell Death in Human Malignant Gliomas

“…Recent reports have observed that AIF is downregulated in many tumor types (Delettre et al, 2006), and depletion of the AIF protein in malignant skin, colon, lung, and breast cells contributes to chemoresistance, supporting AIF pro-cell-death functions in the context of cancer (Huerta et al, 2007). A HER2 antibody-AIF protein chimeric molecule significantly prolonged survival of mice with tumors that over-express HER2 (Yu et al, 2006). Indeed, nuclear BNIP3 repressed AIF expression to a greater extent than other apoptotic proteins as determined by a cDNA microarray analysis (data not shown).…”

HER2-targeting recombinant protein with truncated Pseudomonas Exotoxin: A translocation domain efficiently kills breast cancer cells

“…Our data showed that the transduced lymphocytes had potent and selective cytotoxicity to tumors both in culture and nude mouse models. 13,14,[20][21][22] In this study, we modified this cell-based therapy strategy by delivering the therapeutic molecules into muscle cells neighboring the tumor tissue. In in vivo experiments, we found that ImmunoGrB (PEA253-358aa), ImmunoGrB (PEA275-358aa) and ImmunoGrB (PEA275-280aa) could all inhibit tumor cell growth.…”

“…In previous studies, we have developed a cell-based therapy by genetically modifying lymphocytes to produce and secrete a targeted PEA toxin against HER2-positive tumor cells. 13,14,[20][21][22] In such a strategy, we combined the specificity of antibodies, the potent cytotoxicity of apoptotic executioners, and the effector cell properties of lymphocytes such as homing and tissue penetration. A signal sequence was introduced into the constructs to ensure that the immunotoxins are secreted by genetically modified cells.…”

“…13,23 The PEA translocation domain has been successfully engineered as a vehicle to deliver therapeutic molecules into cells. [15][16][17][18][19] We have previously constructed a series of genes containing different truncated PEA translocation domains (PEA 253-412aa, PEA 253-364aa and PEA253-358aa) fused with the anti-HER2 single-chain antibody (e23sFv) at the 5'-end, and genes encoding diverse apoptosis-inducing molecules such as caspase-3, 20 caspase-6, 21 truncated AIF 22 and granzyme B 13 at the 3'-end. 14 In this study, we attempted to identify the minimal sequence of the PEA translocation domain for further development in therapeutic drugs.…”

Mitochondria as therapeutic targets for cancer chemotherapy

“…Recently, a chimeric protein containing an ErbB-2-specific antibody in the C-terminus and the cytotoxic moiety of AIF in the N-terminus has been shown to direct AIF to ErbB-2-expressing cancer cells, causing their demise (Yu et al, 2006). This strategy of tumor killing could be used for anticancer therapy in vivo, as demonstrated in mice xenotransplanted with human ErbB-2-overexpressing cancer cells when the chimeric protein was produced by Jurkat T-lymphoma cells that were coinoculated (Yu et al, 2006).…”