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Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its receptors became promising molecules for selective targeting of tumor cells without affecting normal tissue. Unfortunately, cancer cells have developed a number of mechanisms that confer resistance to TRAIL\Apo2L-induced apoptosis, which substantiates the need for development of alternative therapeutic strategies. Here we present a recombinant variant of TRAIL\Apo2L peptide, named AD-O53.2, fused to the peptide-derived from Smac/Diablo protein-the natural inhibitor of the apoptotic X-linked IAP (XIAP) protein considered as a pro-apoptotic agent. The proposed mechanism of action for this construct involves specific targeting of the tumor by TRAIL\Apo2L followed by activation and internalization of pro-apoptotic peptide into the cancer cells. While in the cytoplasm , the Smac\Diablo peptide inhibits activity of X-linked IAP (XIAP) proteins and promotes caspase-mediated apoptosis. AD-O53.2 construct was expressed in E.coli and purified by Ion Exchange Chromatography (IEC). Derived protein was initially characterized by circular dichroism spectroscopy (CD), HPLC-SEC chromatography, surface plasmon resonance, protease activation and cell proliferation assays. Our Smac/Diablo-TRAIL fusion variant was tested against a panel of cancer cells (including lung, colorectal, pancreatic, liver, kidney and uterine) and showed a potent cytotoxic effect with the IC50 values in femtomolar range for the most sensitive cell lines, while it remained ineffective against non-transformed HUVEC cells as well as isolated normal human and rat hepatocytes. Importantly, the construct was well tolerated by animals and significantly reduced the rate of the tumor growth in colon and lung adenocarcinoma animal models.

Background The tumor necrosis factor related apoptosis-inducing ligand (TRAIL/Apo2L) is a member of the TNF superfamily that initiates apoptosis of tumor cells through the activation of their death receptors. The ability of TRAIL to selectively induce apoptosis of tumor cells but not normal cells makes it an attractive agent for cancer therapy. However, many cancer types have developed resistance mechanisms, such as dysfunctions of proapoptotic proteins. Hereby, we report a novel molecule - AD-O56.9, which is composed of the soluble fragment of TRAIL (acting as both carrier and also effector) fused with a cationic, alpha-helical (KLAKLAK)2 antimicrobial peptide (acting as effector). The (KLAKLAK)2 peptide fused to protein transduction domain can induce cancer cell death by triggering mitochondrial membrane permeabilization and swelling, resulting in the release of cytochrome c and induction of apoptosis. It creates also the capacity to cause aggregation of mitochondria that is also a mechanism of cytotoxic action. (KLAKLAK)2 peptide is equipped with protein transduction domain domain, to increase its internalization. To allow separation of TRAIL fragment from the effector peptide domain specifically in the tumor environment, we linked these two domains with a sequence motif recognized by MMP and uPa proteases, present in tumor cells membranes or their proximity. Methods AD-O56.9 protein was produced in E. coli and purified by IEC. The molecule was characterized biochemically and biophysically. MTT assay was used to estimate killing of carcinoma cells. Flow cytometric analysis was used to evaluate influence of the AD-O56.9 on plasma and mitochondrial membrane integrity, caspase 3 activation, PARP cleavage, as well as on the cell cycle of cancer cells. The tumoricidal activity of AD-O56.9 was evaluated in NOD/SCID mice bearing different types of tumor xenografts. Results AD-O56.9 exhibited cytotoxic effect on various cancer cell lines, both TRAIL-sensitive and TRAIL-resistant, but showed no toxic effect on normal cells. This protein was also highly cytotoxic against primary cancer cells. The component that overcomes resistance to TRAIL is RRRRRRRR(KLAKLAK)2 peptide, but only as a component of AD-O56.9 fusion protein. Analyzing cell cycle and plasma membrane integrity in relatively sensitive cell line (NCI-H460) and TRAIL-resistant cell line (A549) we showed that AD-O56.9 induced apoptosis in those cells. This protein led to activation of caspase 3, cleavage of PARP as well as caused strong depolarization of mitochondrial membrane. AD-O56.9 administration caused significant regression of TRAIL-sensitive MIA PaCa-2, OE19, Colo205 and TRAIL-resistant HepG2. Conclusions AD-O56.9 is able to induce cell death in many cancer cell lines, even TRAIL resistant and causes tumor regression in mice bearing human tumors. Obtained results make this molecule worth of further preclinical development. Citation Format: Bartlomiej Maciej Zerek, Michal Szymanik, Piotr Kamil Rozga, Anna Pieczykolan, Marlena Galazka, Katarzyna Bukato, Albert Jaworski, Katarzyna Poleszak, Sebastian Dominik Pawlak, Malgorzata Teska-Kaminska, Wojciech Strozek, Jerzy Szczepan Pieczykolan. AD-O56.9: A fusion of TRAIL/Apo2L with a membrane disrupting peptide as a novel anticancer therapeutic. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2773. doi:10.1158/1538-7445.AM2014-2773

Background Cancer growth and development is tightly related to both new vessels formation for tissue remodeling and inhibition of anti-apoptotic signals. Vascular endothelial growth factor (VEGF) is important for vascular development in physiological and pathological processes. Blockade of VEGF pathway has been shown to inhibit both pathological angiogenesis and tumor growth. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) has been under intense scientific evaluation because of its ability to induce apoptosis in cancer cells while omitting normal cells. However, in most cases it wasn't potent enough to become the effective single therapy agent. The AD-O51.4 is a novel anticancer fusion protein. It consists of a recombinant variant of TRAIL/Apo2L fragment, which is linked to the repeated antiangiogenic effector peptide sequence derived from the 6th exon of VEGF ligand. The peptide sequences are separated by a motif recognized by tumor-specific proteases (MMP's, uPa). The structure and biophysical properties of AD-O51.4 should be mostly derived from TRAIL/Apo2L - the carrier component of the fusion molecule. The AD-O51.4 should be targeted to both types: VEGF and TRAIL receptors and lead to sequestration of the VEGF receptors on malignant and endothelial cells making them susceptible to apoptosis induced through TRAIL/Apo2L dead receptors. Methods The AD-O51.4 has been produced in E. coli cells and purified using IEX chromatography. Its structure and biophysical properties were verified using circular dichroism (CD), size-exclusion chromatography (SEC), proteolytic digestion of activation sequence and finally direct N-terminus sequencing. The VEGF and TRAIL/Apo2L receptors specificity was confirmed using surface plasmon resonance (SPR). Antitumor activity was analyzed on a panel of established cancer cell lines and xenograft model of human cancer. Results The analysis of AD-O51.4 revealed secondary structure rich with beta-sheets and a trimeric form of the fusion molecule what is typical for TRAIL/Apo2L ligand. The molecule also displays strong specific binding for both classes of receptors: VEGF and TRAIL/Apo2L what confirms potential antiangiogenic and proapoptotic properties. Sequencing and specific digestion endorsed molecule identity. Finally specific cytotoxic and antitumor activities were confirmed for AD-O51.4. Conclusion We demonstrated that AD-O51.4 fusion protein has well established structure corresponding to its main component TRAIL/Apo2L. The structure of VEGF-derived peptides determines its specific interaction with therapeutic targets and as a consequence its antitumor properties. The obtained results confirm that a combination of two effectors in one protein molecule may be an effective way of anticancer compounds development. Citation Format: Sebastian D. Pawlak, Jerzy S. Pieczykolan, Bartlomiej Zerek, Katarzyna Poleszak, Malgorzata Teska-Kaminska, Marlena Galaska, Michal Szymanik, Albert Jaworski, Anna Pieczykolan, Katarzyna Bukato, Wojciech Strozek, Piotr K. Rozga. Biochemical and biophysical characterization of AD-O51.4 a novel anticancer biological therapeutic agent with dual mechanism of action. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3796. doi:10.1158/1538-7445.AM2014-3796

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) is a promising antitumor agent, but its clinical utility in human malignancies is limited by the resistance mechanism evolved in many cancers types, including overexpresion of antiapoptotic Bcl-2 like proteins and lack or disfunction of proapoptotic agents. Bid is well known proapoptotic factor able to inhibit Bcl-2 proteins after activation by caspases 8 or 10. Bid may also promote apoptosis by forming selective voltage dependent anion-channels in mitochondrial membrane through interaction with Bax protein. AD-O57.4 is a fusion protein consisting of a short peptide derived from Bid linked to an amino terminus of soluble TRAIL domain. The separating sequence contains additional motif recognized by MMPs and uPa proteases that enables cutting-off and releasing the proapoptotic peptide in tumor environment. Activity of AD-O57.4 was examined using a MTT assay on NCI panel and primal, patient derived cancer cell lines. Apoptosis was analyzed by caspase 3 activation and mitochondrial membrane potential change. The expression of Bid was determined by Western Blot analysis. Various of tested cell lines were very sensitive to AD-O57.4 protein with IC50 value between 0.06-173 ng/ml, whereas 5 cell lines showed weak sensitivity or remained resistant. Cytotoxic activity of TRAIL was significantly lower in comparison with AD-O57.4 protein. AD-O57.4 induced relatively strong mitochondrial depolarization both in moderate sensitive cell line (NCI-H460) and TRAIL-resistant cell line (A549). Analysis of caspase 3 activation and expression of Bid protein showed very fast induction of apoptosis by AD-O57.4 in comparison to TRAIL protein. Strong antitumor activity of AD-O57.4 fusion protein was analyzed on the xenograft models of series of human cancer cell lines regarding TRAIL sensitive human colorectal carcinoma Colo205, TRAIL resistant, hepatocellular carcinoma HepG2 and human uterine sarcoma (MES-SA/Dx5) - a multidrug resistant cell line where it caused almost complete tumor regression and showed much higher efficacy than TRAIL alone or standard chemotherapeutic agent. We demonstrated that AD-O57.4 protein has broad in vitro cytotoxic activity against a panel of cancer cell lines and in vivo antitumor activity on xenograft model. Sensitization by AD-O57.4 was dependent on short peptide derived from Bid protein indicating its role for mitochondrial signal amplification in the proapoptotic TRAIL activity. The use of a peptide derived from Bid protein causes a significant increase in potency of TRAIL activity and therefore TRAIL resistant cancer cells can be sensitized by the fusion peptide which can connect extrinsic and intrinsic pathways of apoptosis. Citation Format: Jerzy S. Pieczykolan, Sebastian D. Pawlak, Bartlomiej M. Zerek, Piotr K. Rozga, Anna Pieczykolan, Michal Szymanik, Albert Jaworski, Marlena Galazka, Wojciech Strozek, Katarzyna Wiciejowska, Malgorzata Teska-Kaminska, Lukasz Kutner. Fusion protein capable to initiate two apoptotic pathways in cancer cells resistant to classical PARA's. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5488. doi:10.1158/1538-7445.AM2013-5488

One of the most important mechanisms of tumorgenesis is formation of new blood vessels and tissue remodeling. Vascular endothelial growth factor (VEGF) is one of the most important and widely studied proangiogenic factors, that has an important role in many physiological and pathological processes. Blockade of VEGF pathway has been shown to inhibit both pathological angiogenesis and tumor growth. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) was considered as a promising anticancer agent due its remarkable ability to induce apoptosis in cancer cells without harming normal cells. However, in clinical practice TRAIL efficacy was too low to made it an effective single therapy agent. Here we present a novel fusion protein based on TRAIL/Apo2L, equipped with an antiangiogenic, effector peptide, fused to its N- terminus. The effector role plays a 7-amino acid-long peptide that binds to natural VEGF receptors and competes with their natural ligand. The proposed fusion protein AD-O51.4 consists of extracellular soluble portion of TRAIL linked to two tandemly arranged copies of the effector peptide separated by a sequence containing the motif recognized by tumor-specific proteases (MMP's, uPa). The TRAIL-targeted peptide is able to bind and sequester the VEGF receptors on malignant (cancer) and endothelial cells. As a consequence, the peptide blocks the binding of VEGF ligand, preventing formation of new vessels. In addition, a lot of literature data confirm expression of the VEGF receptors on the surfaces of various cancer cell lines. Due to the presence of VEGF receptors, those cell lines can be also targeted by our VEGF receptor-blocking peptide making them susceptible for TRAIL-induced apoptosis. In vitro, AD-O51.4 showed cytotoxic effect on various cancer cell lines at IC50 below 0.1 ng/mL and no toxic effects on normal cells. Cytotoxic activity of TRAIL alone was significantly lower in comparison to AD-O51.4. We demonstrated that TRAIL/Apo2L-VEGF-antagonist is a strong activator of caspase 3 and Bid processing. Additionally, its direct antiangiogenic activity was confirmed with the ring aortic assay and HUVEC spheroid assay. Strong antitumor activity of novel fusion molecule was also confirmed in xenograft model of multidrug resistant human uterine sarcoma MES-SA/Dx5 where our protein caused complete tumor remission and showed much higher efficacy than TRAIL alone. The similar effect was observed using human colorectal adenocarcinoma Colo205 and human pancreatic carcinoma MIA PaCa-2 xenografts, as well as an orthotropic model of human lung carcinoma NCI-H460-luc2. Citation Format: Jerzy S. Pieczykolan, Piotr Rozga, Anna Pieczykolan, Bartlomiej Zerek, Sebastian D. Pawlak, Michal Szymanik, Albert Jaworski, Marlena Galazka, Katarzyna Wiciejowska, Wojciech Strozek, Malgorzata Teska - Kaminska, Lukasz Kutner, Anna Grochot - Przeczek, Neli Kahmakowa - Trojanowska. Novel fusion molecule with high dual antiangiogenic and anticancer potential. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5073. doi:10.1158/1538-7445.AM2013-5073