A brief history of saporin and its contributions to neuroscience
Shramm PA, Ancheta LR, Bouajram R, Lappi DA (2021) A brief history of saporin and its contributions to neuroscience. Neuroscience 2021 Abstracts J002.11. Society for Neuroscience, Virtual.
Summary: When investigating the origins of targeted toxins (a drug, therapy, or scientific tool directed to a unique extracellular target), an appropriate place to begin is with the Nobel Prize-winning work of Paul Ehrlich and his concept of the “magic bullet.” Over 100 years later, the use of targeted toxins to perform molecular neurosurgery has become a vital practice that allows researchers to observe changes in organisms after eliminating a neuronal population. A prime example of this practice is the specific targeting of cholinergic neurons in the basal forebrain to mimic Alzheimer’s disease (AD). The research tool designed for this purpose is 192-IgG-Saporin, an antibody conjugated to the ribosome-inactivating protein (RIP) Saporin. Researchers have used this targeted toxin for over 30 years. A 2019 publication by Verkhratsky et al. reviews AD models and states this is the only lesion model that specifically targets cholinergic neurons. In 1983, during a quest to find the optimal payload for a targeted toxin, Fiorenzo Stirpe and colleagues discovered Saporin, a plant protein isolated from the common soapwort plant Saponaria officinalis. Unlike ricin and abrin, Saporin does not have a binding chain and cannot enter a cell on its own. Scientists have devised new ways to use Saporin to advance their research and drug development activities. Just a few examples include: 1. A novel suicide gene therapy approach that uses a vector encoding a double-stranded DNA aptamer to deliver the gene encoding Saporin, 2. Delivery of Saporin encapsulated in a nanotechnology system for development of cancer treatments, 3. A deeper understanding of the difference between pain and itch and the relevant pathways, and 4. Development of a stable epilepsy animal model that is used for screening specific treatments that will lead to micro-methods to eliminate the disease. This review will focus on Saporin as the payload delivered to cells. Targeted toxins (typically targeted by an antibody or peptide chemically linked or genetically fused) provide robust tools for neuroscience where ablation of specific neuronal populations is used to study behavior and function. Saporin is an ideal molecule because of its extreme resistance to high temperatures and denaturation, retention of catalytic activity after conjugation, and lack of a binding chain to allow entrance to the cytoplasm of cells on its own. As a result, it is one of the most studied RIPs used for its vigorousness, potency, safety, and ease of use in the laboratory. The information presented will shed light on the history of Saporin, current applications, and what the future holds for this protein in the neuroscience field.
Related Products: Saporin (Cat. #PR-01)
Light-controlled elimination of PD-L1+ cells
Wong JJW, Selbo PK (2021) Light-controlled elimination of PD-L1+ cells. J Photochem Photobiol B 225:112355. doi: 10.1016/j.jphotobiol.2021.112355
Objective: To investigate novel strategies that simultaneously target both tumor cells and immunosuppressive cells in the tumor microenvironment. The focus was on the evaluation in vitro of Anti-PD-L1-SAP combined with photochemical internalization (PCI) as a therapeutic strategy to target and eliminate PD-L1 expressing tumor and immunosuppressive cells.
Summary: The authors show that the intracellular light-controlled drug delivery method induces specific and strongly enhanced cytotoxic effects of Anti-PD-L1-SAP in the PD-L1+ triple-negative breast cancer MDA-MB-231 cell line, while no enhanced efficacy was obtained in the PD-L1 negative control cell line MDA-MB-453.
Usage: Anti-PD-L1-SAP and Streptavidin-ZAP (Control) were used in a cytotoxicity assay.
Related Products: Anti-PD-L1-SAP (Cat. #IT-45), Streptavidin-ZAP (Cat. #IT-27)
Efficacy and selectivity of FGF2-saporin cytosolically delivered by PCI in cells overexpressing FGFR1
Vikan AK, Kostas M, Haugsten EM, Selbo PK, Wesche J (2021) Efficacy and selectivity of FGF2-saporin cytosolically delivered by PCI in cells overexpressing FGFR1. Cells 10(6):1476. doi: 10.3390/cells10061476
Summary: Fibroblast growth factor receptors (FGFRs) have become an attractive target in cancer research and therapy due to their implication in several cancers. The authors evaluated the efficacy and selectivity of PCI of FGF2-saporin (FGF-SAP) in cells overexpressing FGFR1. The authors conclude that to prevent off-target effects of FGF-based toxins, it will be necessary to circumvent binding to HSPGs, for example by mutating the binding site of FGF2 to HSPGs.
Related Products: FGF-SAP (Cat. #IT-38)
CSF-CN contributes to cancer-induced bone pain via the MKP-1-mediated MAPK pathway
Chen P, Pan M, Lin QS, Lin XZ, Lin Z (2021) CSF-CN contributes to cancer-induced bone pain via the MKP-1-mediated MAPK pathway. Biochem Biophys Res Commun 547:36-43. doi: 10.1016/j.bbrc.2021.02.010
Summary: Cerebrospinal fluid-contacting nucleus (CSF–CN) has been reported to be involved in the development of neuropathic pain and inflammatory pain. This study aimed to see whether it also has a role in cancer-induced bone pain (CIBP). Targeted ablation of CSF-CN dramatically aggravated pain sensitivity.
Usage: Injection via icv of CTB-SAP was performed to “knockout” the CSF-CN.
Related Products: CTB-SAP (Cat. #IT-14)
Reciprocal interactions between osteoclasts and nociceptive sensory neurons in bone cancer pain
Andriessen AS, Donnelly CR, Ji RR (2021) Reciprocal interactions between osteoclasts and nociceptive sensory neurons in bone cancer pain. Pain Rep 6(1):e867. doi: 10.1097/PR9.0000000000000867
Summary: Current pharmacotherapies available for bone cancer pain are insufficient to provide safe and efficacious pain relief. The authors discuss the mechanisms used by cancer cells within the bone tumor microenvironment (TME) to drive bone cancer pain.
Usage: Microglial ablation using Mac-1-SAP (15 μg in 8.8 μl i.t.) and Saporin control (Cat. #PR-01, 8.8 μg in 8.8 μl), is sufficient to attenuate nerve injury-induced pain in male, but not female mice.
See: Sorge R et al. Different immune cells mediate mechanical pain hypersensitivity in male and female mice. Nat Neurosci 18:1081-1083, 2015.
Related Products: Mac-1-SAP mouse/human (Cat. #IT-06), Saporin (Cat. #PR-01)
Integrin α10-antibodies reduce glioblastoma tumor growth and cell migration
Masoumi KC, Huang X, Sime W, Mirkov A, Munksgaard Thorén M, Massoumi R, Lundgren-Åkerlund E (2021) Integrin α10-antibodies reduce glioblastoma tumor growth and cell migration. Cancers (Basel) 13(5):1184. doi: 10.3390/cancers13051184
Summary: The authors investigated the treatment effect of two antibodies that have been developed to target the protein integrin 10, which is present on the surface of Glioblastoma (GB) cells. Function-blocking integrin alpha10, beta1-antibodies inhibit GB tumor growth as well as the migration of GB cells. This further validates integrin alpha10, beta1 as a promising target in GB and suggests a novel therapeutic strategy for the treatment of GB and other high-grade gliomas.
Usage: Infusions of anti-integrin α10β1-SAP or Anti-ctrl-SAP were made icv (1 µg/2 L per infusion).
See: Thorén MM et al. Integrin α10, a Novel Therapeutic Target in Glioblastoma, Regulates Cell Migration, Proliferation, and Survival. Cancers (Basel) 11(4):587, 2019.
Related Products: Custom Conjugates
The HIF-1α antisense long non-coding RNA drives a positive feedback loop of HIF-1α mediated transactivation and glycolysis.
Zheng F, Chen J, Zhang X, Wang Z, Chen J, Lin X, Huang H, Fu W, Liang J, Wu W, Li B, Yao H, Hu H, Song E (2021) The HIF-1α antisense long non-coding RNA drives a positive feedback loop of HIF-1α mediated transactivation and glycolysis. Nat Commun 12(1):1341. doi: 10.1038/s41467-021-21535-3
Objective: To investigate the contributions of HIF-1 in regulating glycolysis of cancer cells under hypoxia
Summary: HIF Antisense LncRNA (HIFAL) has a critical regulatory role in HIF-1-driven transactivation and glycolysis, identifying HIFAL as a therapeutic target of cancer treatment.
Usage: Western blot (1:500)
Related Products: Trans-4-Hydroxy-L-Proline Rabbit Polyclonal, Conjugated (Cat. #AB-T044)
Identification of prostaglandin F2 receptor negative regulator (PTGFRN) as an internalizable target in cancer cells for antibody-drug conjugate development
Marquez J, Dong J, Dong C, Tian C, Serrero G (2021) Identification of prostaglandin F2 receptor negative regulator (PTGFRN) as an internalizable target in cancer cells for antibody-drug conjugate development. PLoS One 16(1):e0246197. doi: 10.1371/journal.pone.0246197
Summary: PTGFRN is a cell-surface protein that is upregulated in certain cancer types, including head and neck and, notably, pediatric medulloblastoma, an aggressive cancer with limited therapeutic options. With the selection of the mouse monoclonal antibody 33B7, the authors identified PTGFRN as a potential therapy target, and show that it is internalized by incubation with 33B7. Purified 33B7 antibody was sent to Advanced Targeting Systems where saporin was directly conjugated to the Fc region of 33B7 using their proprietary cleavable linker.
Usage: In a 96-well plate, 2000 cells/well were plated in triplicate in 100 μL of DMEM/F12 medium supplemented with 2.5% FBS, 0.4 ug/ml 33B7 antibody, and 0.9ug/ml of Fab-ZAP mouse. As an isotype control, cells were incubated with mouse Fab IgG-SAP as control (instead of 33B7) and Fab-ZAP.
Related Products: Fab-ZAP mouse (Cat. #IT-48), Fab IgG-SAP (Cat. #IT-67), Custom Conjugates
Chronic pain in dogs (Dolor crónico en el perro)
Puente BR (2021) Chronic pain in dogs (Dolor crónico en el perro). Zaragoza Spain: Gruppo Asis Biomedia, S. L..
Summary: The author presents a thorough overview of aspects of canine chronic pain. He includes SP-SAP (Substance P-Saporin) as an experimental drug, “its use as an adjuvant analgesic in dogs with bone cancer has been studied,”
Related Products: SP-SAP (Cat. #IT-07)
Pseudomonas Exotoxin A based toxins targeting epidermal growth factor receptor for the treatment of prostate cancer
Fischer A, Wolf I, Fuchs H, Masilamani AP, Wolf P (2020) Pseudomonas Exotoxin A based toxins targeting epidermal growth factor receptor for the treatment of prostate cancer. Toxins (Basel) 12(12):753. doi: 10.3390/toxins12120753
Summary: Refers to chimeric murine-human mAb cetuximab bound to Streptavidin-ZAP.
See: Yip WL et al. Targeted Delivery and Enhanced Cytotoxicity of Cetuximab-Saporin by Photochemical Internalization in EGFR-Positive Cancer Cells. Mol Pharm 4(2):241-251, 2007.
Related Products: Streptavidin-ZAP (Cat. #IT-27)
Cellular uptake of vitamin B12: Role and fate of TCblR/CD320, the transcobalamin receptor.
Gick GG, Arora K, Sequeira JM, Nakayama Y, Lai SC, Quadros EV (2020) Cellular uptake of vitamin B12: Role and fate of TCblR/CD320, the transcobalamin receptor. Exp Cell Res 396(1):112256. doi: 10.1016/j.yexcr.2020.112256
Summary: The increased and sustained expression of TCblR in proliferating cells has been used to target toxins preferentially to cancer cells and can be potentially used for targeted delivery of other anti-cancer drugs. In 2010 the authors published a paper which evaluated the potential of using immunotoxins to eliminate cancer cells expressing TCblR the authors performed a series of in vitro experiments using their monoclonal antibody plus Mab-ZAP in varying concentrations. The results indicated that this is a viable therapeutic model that causes minimal peripheral damage.
Related Products: Mab-ZAP (Cat. #IT-04)
The EphA2 and cancer connection: potential for immune-based interventions
London M, Gallo E (2020) The EphA2 and cancer connection: potential for immune-based interventions. Mol Biol Rep 47(10):8037-8048. doi: 10.1007/s11033-020-05767-y
Summary: The authors review the most current mAb-based therapies against EphA2-expressing cancers currently in pre-clinical and/or clinical stages. They reference Sakamoto et al. who performed in vitro testing of two different EphA2 mAbs mixed with Mab-ZAP to discover their therapeutic potential against melanoma.
See: Sakamoto A et al. An Agonistic Antibody to EPHA2 Exhibits Antitumor Effects on Human Melanoma Cells. Anticancer Res 38:3273-3282, 2018.
Related Products: Mab-ZAP (Cat. #IT-04)
Prolyl hydroxylase substrate adenylosuccinate lyase is an oncogenic driver in triple negative breast cancer
Zurlo G, Liu X, Takada M, Fan C, Simon JM, Ptacek TS, Rodriguez J, von Kriegsheim A, Liu J, Locasale JW, Robinson A, Zhang J, Holler JM, Kim B, Zikánová M, Bierau J, Xie L, Chen X, Li M, Perou CM, Zhang Q (2019) Prolyl hydroxylase substrate adenylosuccinate lyase is an oncogenic driver in triple negative breast cancer. Nat Commun 10(1):5177. doi: 10.1038/s41467-019-13168-4
Objective: To investigate the role of ADSL hydroxylation in controlling cMYC and triple negative breast cancer (TNBC) tumorigenesis.
Summary: ADSL regulates cMYC protein level through adenosine levels and leads to downstream metabolic changes and breast cancer cell proliferation. ADSL is essential for TNBC cell growth and invasiveness and contributes to TNBC breast tumorigenesis and metastasis in vivo.
Usage: Western blot
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Sulfisoxazole inhibits the secretion of small extracellular vesicles by targeting the endothelin receptor A.
Im E-J, Lee C-H, Moon P-G, Rangaswamy GG, Lee B, Lee JM, Lee J-C, Jee J-G, Bae J-S, Kwon T-K, Kang K-W, Jeong M-S, Lee J-E, Jung H-S, Ro H-J, Jun S, Kang W, Seo S-Y, Cho Y-E, Song B-J, Baek M-C (2019) Sulfisoxazole inhibits the secretion of small extracellular vesicles by targeting the endothelin receptor A. Nature Commun 10(1):1387. doi: 10.1038/s41467-019-09387-4
Objective: To identify a direct protein target of SFX in cancer cells.
Summary: Using data from the BindingDB, SEA identified four proteins as target candidates, which are: endothelin receptor type A, kynurenine 3-monooxygenase, carbonic anhydrase 13, and angiotensin II type 1a receptor.
Usage: Western blot (1:1000).
Related Products: Angiotensin II receptor (AT-1R) Rabbit Polyclonal, affinity-purified (Cat. #AB-N27AP)
Conservation of oncofetal antigens on human embryonic stem cells enables discovery of monoclonal antibodies against cancer
Tan HL, Yong C, Tan BZ, Fong WJ, Padmanabhan J, Chin A, Ding V, Lau A, Zheng L, Bi X, Yang Y, Choo A (2018) Conservation of oncofetal antigens on human embryonic stem cells enables discovery of monoclonal antibodies against cancer. Sci Rep 8:11608. doi: 10.1038/s41598-018-30070-z
Objective: To identify and characterize an antibody raised using human embryonic stem cells with potential as a cancer therapeutic.
Summary: Antibody A19 not only binds to undifferentiated hESCs by flow cytometry, it also reacts with ovarian and breast cancer cell lines with low or no binding to normal cells.
Usage: in vitro – Number of viable cells treated showed a decrease in cell number (Hum-ZAP mixed with A19; Streptavidin-ZAP mixed with biotinylated A19). To determine if there were off-target effects, Hum-ZAP and chA19 were incubated with a non-binding cell line OVCAR10; no apparent cytotoxicity was observed. invivo – 5 x 106 SKOV3 cells were implanted s.c. in NUDE mice and Biotinylated A19-Streptavidin-ZAP (ADC), administered ip. The controls were free Saporin and naked A19. By the end of 10 weeks, mice administered with the ADC saw a 60% reduction in tumor size compared to control groups.
Related Products: Hum-ZAP (Cat. #IT-22), Streptavidin-ZAP (Cat. #IT-27), Saporin (Cat. #PR-01)
Role of GPCR (mu-opioid)-receptor tyrosine kinase (epidermal growth factor) crosstalk in opioid-induced hyperalgesic priming (type II).
Araldi D, Ferrari LF, Levine JD (2018) Role of GPCR (mu-opioid)-receptor tyrosine kinase (epidermal growth factor) crosstalk in opioid-induced hyperalgesic priming (type II). Pain 159(5):864-875. doi: 10.1097/j.pain.0000000000001155
Objective: To determine the the mechanisms mediating the induction of opioid-induced hyperalgesia and the prolongation of prostaglandinE2-induced hyperalgesia in type II hyperalgesic priming.
Summary: Understanding the mechanisms responsible for the induction of type II hyperalgesic priming, a form of neuroplasticity in the peripheral terminal of the primary afferent nociceptor, may provide useful information for the design of drugs with improved therapeutic profiles to treat neuroplasticity induced by chronic use of opioids.
Usage: SSP-SAP was prepared in saline (5 ng/mL), and 20 mL was injected intrathecally into rats, 14 days before nociceptive tests.
Related Products: SSP-SAP (Cat. #IT-11)
Synergistic cytotoxic effect on gastric cancer cells of an immunotoxin cocktail in which antibodies recognize different epitopes on CDH17
Kusano-Arai O, Iwanari H, Kudo S, Kikuchi C, Yui A, Akiba H, Matsusaka K, Kaneda A, Fukayama M, Tsumoto K, Hamakubo T (2018) Synergistic cytotoxic effect on gastric cancer cells of an immunotoxin cocktail in which antibodies recognize different epitopes on CDH17. Monoclon Antib Immunodiagn Immunother 37:1-11. doi: 10.1089/mab.2017.0043
Objective: To determine if an immunotoxin cocktail targeted to multiple epitopes has synergistic effects on low expression level cells, which would expand the applicable range of immunotoxin therapy for cancer.
Summary: The combination of immunotoxins with different mechanisms of action in an antibody cocktail will increase cytotoxic activities and decrease side effects.
Usage: The authors applied a monoclonal antibody (mAb) cocktail for one target protein with multiple epitopes. They generated anti-CDH17 mAbs recognizing different epitopes on CDH17 (Cadherin-17). CDH17 is expressed in gastric cancer, hepatocellular carcinoma, colorectal cancer, and pancreatic cancer and has limited distribution in normal tissues. For preparation of 3 immunotoxins, Streptavidin-ZAP was mixed with biotinylated mAbs in equimolar concentrations for 30 minutes at room temperature. The study provides data to demonstrate that the cocktail of different epitope-recognizing immunotoxins has synergistic cytotoxic effects on CDH17-expressing cells.
Related Products: Streptavidin-ZAP (Cat. #IT-27)
Targeting of embryonic annexin A2 expressed on ovarian and breast cancer by the novel monoclonal antibody 2448
Cua S, Tan HL, Fong WJ, Chin A, Lau A, Ding V, Song Z, Yang Y, Choo A (2018) Targeting of embryonic annexin A2 expressed on ovarian and breast cancer by the novel monoclonal antibody 2448. Oncotarget 9:13206-13221. doi: 10.18632/oncotarget.24152
Objective: To develop mAbs to potentially target oncofetal antigens and be repurposed for antibody or antibody drug conjugate (ADC) therapy.
Summary: The novel IgG1, 2448, was shown to target a unique glycosylated surface epitope on ANXA2. As a possible therapeutic candidate for ovarian and breast cancer, 2448 demonstrated anti-tumor activity via two independent mechanisms of action.
Usage: Cells were seeded in 96-well plates at 1000 or 2000 cells/well. Primary antibody, 2448 or ch2448 (10 μg/mL) was pre-mixed with appropriate secondary saporin conjugate, Mab-ZAP or Hum-ZAP. The most significant decreases in cell viability (20% to 60%) were observed against the epithelial IGROV1 and MCF7 cell lines. ATS created a Custom ADC by direct conjugation of saporin to ch2448 (ch2448-SAP). As a control, an isotype chimeric IgG was also conjugated to saporin (IgG-SAP). Compared to using secondary saporin conjugates, ch2448-SAP induced and increase of 20–30% cytotoxicity.)
Related Products: Mab-ZAP (Cat. #IT-04), Hum-ZAP (Cat. #IT-22), Custom Conjugates
5-FU resistant EMT-like pancreatic cancer cells are hypersensitive to photochemical internalization of the novel endoglin-targeting immunotoxin CD105-saporin
Lund K, Olsen CE, Wong JJW, Olsen PA, Solberg NT, Høgset A, Krauss S, Selbo PK (2017) 5-FU resistant EMT-like pancreatic cancer cells are hypersensitive to photochemical internalization of the novel endoglin-targeting immunotoxin CD105-saporin. J Exp Clin Cancer Res 36(1):185.. doi: 10.1186/s13046-017-0662-6
Objective: Investigate resistance mechanisms and photochemical strategies to overcome 5-FU resistance in pancreatic adenocarcinoma.
Summary: Expression of CD105 was investigated using RT-qPCR, western blotting, flow cytometry, and fluorescence microscopy, and co-localization of TPCS2a and Anti-CD105-SAP was assessed using microscopy. MTS assay was used to investigate cytotoxic effects of photochemical internalization of Anti-CD105-SAP. For the first time, we demonstrate the promise of PCI-based targeting of CD105 in site-specific elimination of 5-FU resistant pancreatic cancer cells using Anti-CD105-SAP in vitro. PCI-based targeting of CD105 may represent a potent anti-cancer strategy and should be further evaluated in preclinical models.
Usage: Cells were seeded (3000/well) in 96-well plates and allowed to attach overnight. The cells were incubated with the Anti-CD105-saporin (2.4 nM) or Saporin as a control (6.48 nM; Saporin was added in a molecular ratio of 2.7:1 to the immunotoxin) giving an equal ratio of Saporin to immunotoxin), with or without the photosensitizer TPCS2a (0.35 μg/ml) for 18 h.
Related Products: Anti-CD105-SAP (Cat. #IT-80)
Enhancement of anti-Robo1 immunotoxin cytotoxicity to head and neck squamous cell carcinoma via photochemical internalization
Komatsu N, Mitsui K, Kusano-Arai O, Iwanari H, Hoshi K, Takato T, Abe T, Hamakubo T (2017) Enhancement of anti-Robo1 immunotoxin cytotoxicity to head and neck squamous cell carcinoma via photochemical internalization. Arch Can Res 5:157-163. doi: 10.21767/2254-6081.100157
Objective: To screen a monoclonal antibody to Robo1, an axon guidance receptor, for its suitability to target various cancers.
Summary: Conventional treatment exhibited an inadequate cytotoxic effect. With the addition of a photosensitizer and LED light illumination, the cytotoxic effect was remarkably improved.
Usage: Saporin-conjugated anti-Robo1 and Saporin-conjugated negative control antibody were prepared by incubating 2 mcl of 1.1 micromolar Streptavidin-ZAP (Biotin Z Internalization Kit) and 2 mcl of 1.1 micromolar biotinylated antibody for 30 min at room temperature.
Related Products: Streptavidin-ZAP (Cat. #IT-27)
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