PubMed Health⌕ Search

Biomedical subjects

Raj K Puri

Publications and source records attributed to Raj K Puri.

At least 55 records · Page 3Linked to original sources
PubMed2004

Distribution kinetics of targeted cytotoxin in glioma by bolus or convection-enhanced delivery in a murine model.

OBJECT: Interleukin-13 receptor (IL-13R)-targeted cytotoxin (IL-13-PE38) displays a potent antitumor activity against a variety of human tumors including glioblastoma multiforme (GBM) and, thus, this agent is being tested in the clinical trial for the treatment of recurrent GBM. In this study, the authors determined the safety and distribution kinetics of IL-13 cytotoxin when infused intracranially by a bolus injection and by convection-enhanced delivery (CED) in an athymic nude mouse model of GBM. METHODS: For the safety studies, athymic nude mice were given intracranial infusions of IL-13 cytotoxin into normal parenchyma by either a bolus injection or a 7-day-long CED. Toxicity was assessed by performing a histological examination of the mouse brains. For the drug distribution studies, nude mice with intracranially implanted U251 GBM tumors were given an intratumor bolus or a CED infusion of IL-13 cytotoxin. Brain tumor samples obtained between 0.25 and 72 hours after the infusion were assessed for drug distribution kinetics by performing immunohistochemical and Western blot analyses. Based on the histological changes in the tumor and brain, the maximum tolerated dose of intracranial IL-13 cytotoxin infusion in nude mice was determined to be 4 microg when delivered by a bolus injection and 10 microg when CED was used. Drug distribution reached the maximum level 1 hour after the bolus injection and the volume of distribution was determined to be 19.3 +/- 5.8 mm3. Interleukin-13 cytotoxin was barely detectable 6 hours after the injection. Interestingly, when delivered by bolus injections IL-13 cytotoxin exhibited superior distribution in larger rather than smaller tumors. Convection-enhanced delivery was superior for drug distribution in the U251 tumors because when CED was used the drug remained in the tumors 6 hours after the infusion. CONCLUSIONS: These studies provide confirmation of a previous hypothesis that CED of IL-13 cytotoxin is superior to bolus injections not only for the safety of the normal brain but also for maintaining drug levels for a prolonged period in infused brain tumors. These findings are highly relevant and important for the optimal clinical development of IL-13 cytotoxin or any other targeted antitumor agent for GBM therapy, in which multiple routes of delivery of an agent are being contemplated.

Animals↗
PubMed2004

Specifically targeted killing of interleukin-13 (IL-13) receptor-expressing breast cancer by IL-13 fusion cytotoxin in animal model of human disease.

Interleukin-13 receptor (IL-13R) alpha2 chain binds IL-13 with high affinity and can internalize after binding to ligand. We have exploited this property of IL-13Ralpha2 chain by receptor-targeted breast cancer therapy. Previous studies have demonstrated that in vivo intratumoral (i.t.) gene transfer of this chain followed by IL-13 cytotoxin [comprised of IL-13 and Pseudomonas exotoxin (IL13-PE38QQR)] therapy causes regression of established human tumors in xenografted models. Breast carcinoma cells do not express IL-13Ralpha2 chain and are resistant to the antitumor effect of IL-13 cytotoxin. To determine whether IL-13Ralpha2 chain can render sensitivity of breast cancer to IL-13 cytotoxin, we injected IL-13Ralpha2 plasmid in s.c. established tumors by i.t. route, followed by systemic or i.t. IL-13 cytotoxin administration. This combination approach showed profound antitumor activity against human breast tumors in xenografted immunodeficient mice. Interestingly, there was dominant infiltration of inflammatory cells in regressing tumors, which were identified to be macrophages producing nitric oxide (NO) and natural killer cells. The partial role of inducible nitric oxide synthase (iNOS)-positive macrophages was confirmed by in vivo macrophage depletion experiments. Serum chemistry, hematology, and organ histology from treated mice did not show any remarkable toxicity resulting from the combination therapy. Taken together, local gene transfer of IL-13Ralpha2 followed by receptor-targeted IL-13 cytotoxin therapy may be applied safely and effectively to the treatment of localized breast cancer.

Animals↗
PubMed2003

Gene expression in human embryonic stem cell lines: unique molecular signature.

Human embryonic stem (huES) cells have the ability to differentiate into a variety of cell lineages and potentially provide a source of differentiated cells for many therapeutic uses. However, little is known about the mechanism of differentiation of huES cells and factors regulating cell development. We have used high-quality microarrays containing 16 659 seventy-base pair oligonucleotides to examine gene expression in 6 of the 11 available huES cell lines. Expression was compared against pooled RNA from multiple tissues (universal RNA) and genes enriched in huES cells were identified. All 6 cell lines expressed multiple markers of the undifferentiated state and shared significant homology in gene expression (overall similarity coefficient > 0.85).A common subset of 92 genes was identified that included Nanog, GTCM-1, connexin 43 (GJA1), oct-4, and TDGF1 (cripto). Gene expression was confirmed by a variety of techniques including comparison with databases, reverse transcriptase-polymerase chain reaction, focused cDNA microarrays, and immunocytochemistry. Comparison with published "stemness" genes revealed a limited overlap, suggesting little similarity with other stem cell populations. Several novel ES cell-specific expressed sequence tags were identified and mapped to the human genome. These results represent the first detailed characterization of undifferentiated huES cells and provide a unique set of markers to profile and better understand the biology of huES cells.

Animals↗
PubMed2003

Interleukin-13 receptor alpha2 chain in human head and neck cancer serves as a unique diagnostic marker.

Previous studies have demonstrated that approximately 30% of squamous cell carcinoma of the head and neck (SCCHN) cell lines express high levels of interleukin-13 receptor(s) (IL-13R). However, the incidence, expression level, and significance of IL-13R expression in human tumor specimens is not known. In addition, it is not known whether normal head and neck tissues express IL-13R. In this study, we evaluated the expression of IL-13R subunits (IL-13Ralpha1, IL-13Ralpha2, and IL-4Ralpha) in 337 surgically excised specimens of SCCHN and normal head and neck tissues. Specimens were obtained from 139 patients with SCCHN and 16 patients with benign tonsil disorders from two centers in the United States and Japan and evaluated with immunohistochemistry and in situ hybridization. Extensive analysis demonstrated that the majority of SCCHN tumors uniformly expressed low levels of IL-13Ralpha1 chain; however, 77% of the tumors expressed moderate to high levels of IL-4Ralpha, which forms a signaling complex with IL-13Ralpha1 chain. On the other hand, 33% of SCCHN tumors expressed moderate to high levels of IL-13Ralpha2 chain. Using tissue array from 99 patients, we observed that the expression levels of IL-13Ralpha2 and IL-4Ralpha were significantly higher in SCCHN than in normal head and neck tissues (P < 0.005). Detailed analysis of clinicopathological features demonstrated a positive statistically significant correlation between IL-13Ralpha2 expression and clinically advanced primary SCCHN tumor (T(4); Tumor-Node-Metastasis classification; P < 0.05). However, there was no correlation among IL-13R expression and sex, age of patients, stage of lymph node metastasis, squamous cell carcinoma grade, or allergic history. Taken together, this study suggests that IL-13R may be involved in SCCHN tumor progression, and 33% of IL-13Ralpha2-positive SCCHN cases may be targeted by IL-13 cytotoxin and IL-13R-targeted agent.

Biomarkers, Tumor↗
PubMed2003

Antitumor therapy with bacterial DNA and toxin: complete regression of established tumor induced by liposomal CpG oligodeoxynucleotides plus interleukin-13 cytotoxin.

Despite urgent need, no single strategy has been widely effective at controlling the growth of rapidly progressive solid tumors. We demonstrate here a potent antitumor therapy using modified bacterial DNA and toxin. Treatment of human head and neck cancer established as xenografts in athymic mice with immunostimulatory CpG oligodeoxynucleotides encapsulated in sterically stabilized cationic liposome [(CpG ODN)(SSCL)] and recombinant interleukin-13 Pseudomonas exotoxin (IL13-PE) significantly reduced the tumor growth followed by complete regression in most animals. The antitumor activity of (CpG ODN)(SSCL) was dependent on natural killer cells that infiltrated within tumors. Interestingly, IL13-PE enhanced (CpG ODN)(SSCL)-induced natural killer cell activity and cytokine production in vivo and in vitro. These data strongly suggest that a combination of innate immune activation by (CpG ODN)(SSCL) and tumor-directed targeting by IL13-PE is a novel approach for human cancer immunotherapy.

Animals↗
PubMed2003

Multidrug-resistant tumor cells remain sensitive to a recombinant interleukin-4-Pseudomonas exotoxin, except when overexpressing the multidrug resistance protein MRP1.

Tumor cells may become resistant to conventional anticancer drugs through the occurrence of transmembrane transporter proteins such as P-glycoprotein (ABCB1), breast cancer resistance protein (ABCG2), or members of the multidrug resistance-associated protein family (MRP1-MRP5; ABCC1-ABCC5). In this report, we studied whether tumor cells that are cytostatic drug resistant because of overexpression of one of the above mentioned proteins are sensitive to a new anticancer agent, interleukin-4 toxin (IL-4 toxin). IL-4 toxin is a fusion protein composed of circularly permuted IL-4 and a truncated form of Pseudomonas exotoxin (PE) [IL-4(38-37)-PE38KDEL]. Ninety-six-h cytotoxicity assays and 10-day clonogenic assays showed that drug-selected multidrug resistant (MDR) tumor cells that overexpress P-glycoprotein or breast cancer resistance proteins are still sensitive to IL-4 toxin. Also, tumor cells transfected with cDNA for MRP2-5 showed no resistance, or marginal resistance, only to the toxin as compared with the parent cells. In contrast, MRP1-overexpressing cells, both drug selected and MRP1 transfected, are clearly resistant to IL-4 toxin with resistance factors of 4.3 to 8.4. MRP1-overexpressing cells were not resistant to PE itself. IL-4 toxin resistance in MRP1-overexpressing cells could be reversed by the MRP1 inhibitors probenecid or MK571 and were not affected by glutathione depletion by DL-buthionine-S,R-sulfoximine. In a transport assay using plasma membrane vesicles prepared from MRP1-overexpressing cells, IL-4 toxin and IL-4, but not PE, inhibited the translocation of the known MRP1 substrate 17beta-estradiol 17-(beta-D-glucuronide) (E(2)17betaG). These data suggest that MRP1-overexpressing cells are resistant to IL-4 toxin because of extrusion of this agent by MRP1. Still, the results of this study demonstrate that IL-4 toxin effectively kills most MDR tumor cells and, therefore, represents a promising anticancer drug.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2003

Therapeutic attenuation of pulmonary fibrosis via targeting of IL-4- and IL-13-responsive cells.

Severe forms of idiopathic interstitial pneumonia (IIP), such as usual interstitial pneumonia, can be impervious to modern steroid and immunosuppressive treatment regimens, thereby emphasizing the need for novel effective therapies. Consequently, research attention has been directed toward understanding the cytokine networks that may affect fibroblast activation and, hence, the progression of certain IIPs. This led us to investigate whether the specific targeting of resident lung cells responsive to IL-4 and IL-13 exerted a therapeutic effect in an experimental model of IIP, namely the bleomycin-induced model of pulmonary fibrosis. IL-4, IL-13, and their corresponding receptor subunits, IL-4Ralpha, IL-13Ralpha1, and IL-13Ralpha2, were maximally expressed at the mRNA and protein levels in whole lung samples on day 21 or 28 after an intratracheal bleomycin challenge. The intranasal administration of an IL-13 immunotoxin chimeric molecule (IL13-PE) from days 21-28, but not for 1-wk periods at earlier times, after bleomycin challenge had a significant therapeutic effect on histological and biochemical parameters of bleomycin-induced pulmonary fibrosis compared with the control group. The intranasal IL13-PE therapy significantly reduced the numbers of IL-4 and IL-13 receptor-positive mononuclear cells and macrophages and the levels of profibrotic cytokine and chemokine in the lungs of bleomycin-challenged mice on day 28. Thus, this study demonstrates that IL-4- and/or IL-13-binding cells are required for the maintenance of pulmonary fibrosis induced by bleomycin and highlights the importance of further investigation of antifibrotic therapeutics that target these cells during pulmonary fibrosis.

Administration, Intranasal↗
PubMed2003

MIP-T3 associates with IL-13Ralpha1 and suppresses STAT6 activation in response to IL-13 stimulation.

To unravel the mechanism of interleukin-13 (IL-13)-specific functions, we sought to identify IL-13 receptor (IL-13R) binding molecules. A novel human IL-13Ralpha1 binding protein (IL13RBP1) has been identified using yeast tri-hybrid system, which was found to encode the same protein as MIP-T3 (microtubule interacting protein that associates with tumor necrosis factor (TNF) receptor associating factor-3 (TRAF3)). It constitutively associates with IL-13Ralpha1 and suppresses IL-4/13-induced signal transducer and activator of transcription-6 (STAT6) phosphorylation. IL-13-induced STAT6 activation was also inhibited as determined by dual luciferase assay and electrophoretic mobility shift assay (EMSA). These results suggest that MIP-T3 is a novel inhibitor of IL-13 signaling and may be a useful molecule in ameliorating various conditions in which IL-13 plays a central role.

Animals↗
PubMed2003

Tumor regression mechanisms by IL-13 receptor-targeted cancer therapy involve apoptotic pathways.

IL-13 cytotoxin, composed of IL-13 and a truncated form of Pseudomonas exotoxin, targets IL-13R-overexpressing tumor cell lines in vitro and in vivo. To reveal the molecular mechanism of IL-13 cytotoxin-induced cell death in vivo, we demonstrate activation of apoptotic pathways in 2 s.c. growing human SCCHN tumor models in immunodeficient mice after i.t. administration of IL-13 cytotoxin. Treatment of HN12 tumor bearing mice with i.p. or i.t. administration of IL-13 cytotoxin mediated marked regression of established tumors with complete remission. Interestingly, after a single i.t. administration, IL-13 cytotoxin disappeared within 6 hr but accumulation of caspase-3, -8 and -9 and cleavage of procaspase-3 and PARP continued within the tumors for a prolonged period. We further demonstrate that IL-13 cytotoxin also utilizes an alternate pathway of cell death via the release of cytochrome c from mitochondria to the cytosol. Our results indicate that IL-13 cytotoxin induces 2 major pathways of apoptosis, which may play a role in tumor regression. In addition, apoptotic molecules may serve as surrogate molecular markers of tumor response to IL-13R-directed cytotoxin therapy.

ADP Ribose Transferases↗
PubMed2003

Impact of interleukin-13 responsiveness on the synthetic and proliferative properties of Th1- and Th2-type pulmonary granuloma fibroblasts.

Interleukin-13 (IL-13) has emerged as a major cytokine mediator of fibroblast activation and pulmonary fibrosis. Normal (from noninflamed lung), Th1-type (induced by the pulmonary embolization of purified peptide derivative-coated beads in mice sensitized to purified peptide derivative), and Th2-type (induced by the pulmonary embolization of Schistosoma mansoni egg antigen-coated beads in mice sensitized with S. mansoni eggs) primary fibroblast cell lines all exhibited constitutive gene expression of two receptor chains that bind and signal IL-13-mediated cellular events: IL-4Ralpha and IL-13Ralpha1. However, all three fibroblast cell lines exhibited divergent synthetic and proliferative responses to the exogenous addition of either recombinant IL-13 or a chimeric protein comprised of IL-13 and a truncated version of Pseudomonas exotoxin (IL13-PE), which targets and kills IL-13 receptor overexpressing cells. The exogenous addition of IL-13 to Th1-type and Th2-type fibroblast cultures significantly increased the cellular expression of IL-13Ralpha2, which may function as an IL-13 decoy receptor. After a 24-hour exposure to IL-13, the total collagen generation and cellular proliferation by Th2-type fibroblasts were significantly higher than that observed in similar numbers of normal and Th1-type fibroblasts. In addition IL13-PE, which binds with highest affinity to IL-13Ralpha2, exhibited down-regulatory effects on proliferation and matrix generation expression by Th1- and Th2-type, but not normal, fibroblasts. Thus, these data demonstrate that fibroblasts derived from murine pulmonary granulomas exhibit divergent expression of functional IL-13 receptor and this expression dictates the responsiveness and susceptibility to recombinant IL-13 and IL-13 immunotoxin, respectively.

Animals↗
PubMed2003

Interleukin-13 receptor-directed cytotoxin for malignant glioma therapy: from bench to bedside.

Central nervous system malignant neoplasias, in particular, glioblastoma multiforme (GBM) have defied all current therapeutic modalities. New therapies involving tumor targeting approach are being explored. This approach relies on the identification of unique or over-expressed cell surface receptors or antigens on tumor cells. In that regard, we have identified receptor for an immune regulatory cytokine, interleukin-13 (IL-13), which is over-expressed on human malignant glioma cell lines and primary tumor cell cultures. To target IL-13 receptors (IL-13R) for cancer therapy, we have developed a recombinant fusion protein composed of IL-13 and a mutated form of Pseudomonas exotoxin (IL13-PE38QQR or IL-13 cytotoxin). The IL-13 cytotoxin was found to be highly selective and potent in killing human GBM cells in vitro while normal cells including immune cells, endothelial cells and normal brain cells were generally spared the cytotoxic effect of IL-13 cytotoxin. This is because these cells either expressed none or expressed low levels of IL-13R. Consistent with in vitro cytotoxic activity, IL-13 cytotoxin mediated remarkable anti-tumor activity to human glioma in animal xenograft models. The direct injection of IL-13 cytotoxin into subcutaneous human GBM tumors grown in nude mice produced complete and durable regression of established tumors. Intravenous and intraperitoneal administration of IL-13 cytotoxin also reduced tumor burden significantly with fewer complete responders. All animals tolerated therapy well with minimal toxicity to vital organs. Pre-clinical safety and toxicity studies were performed in mice, rats and monkeys. Systemic administration of IL-13 cytotoxin appeared to be well tolerated at high doses (up to 50 microg/kg). Intrabrain parenchyma administration of IL-13 cytotoxin at doses up to 100 microg/ml was very well tolerated without any evidence of gross or microscopic necrosis, whereas at 500 microg/ml dose, localized necrosis was observed in normal rat brain. Based on these encouraging pre-clinical studies, three Phase I/II clinical trials in adults with malignant glioma have been initiated. The first clinical trial involves convection-enhanced delivery (CED) of IL-13 cytotoxin into recurrent malignant glioma. This route of IL-13 cytotoxin administration appears to be fairly well tolerated with no neurotoxicity. The second clinical trial involves infusion of IL-13 cytotoxin by CED following tumor resection. The initial stage of the second study assessed histologic effect of drug administered prior to resection. In third one, IL-13 cytotoxin is infused by CED followed by tumor resection. All three clinical trials are currently ongoing.

Animals↗
PubMed2003

Combination fusion protein therapy of refractory brain tumors: demonstration of efficacy in cell culture.

Primary brain tumors including anaplastic astrocytomas and glioblastoma multiforme are difficult to treat because of their locally invasive nature and relative resistance to chemotherapy and radiation therapy. Novel agents that can kill multi-drug resistant tumor cells and reach tumor cells at distant sites in the brain are needed. One such class of agents is fusion proteins which consist of brain-tumor-selective peptide ligands fused to peptide toxins. The ligand directs the protein to the glioma cell surface; the peptide toxin is then internalized into the cell, translocates to the cytosol and catalytically inactivates protein synthesis leading to cell death. Fusion proteins are toxic to multi-drug resistant brain tumor cells. Because of the large molecular weight of these molecules, a unique delivery system has been developed--convection-enhanced delivery (CED). The method creates a bulk flow which supplements diffusion and achieves drug concentrations in the brain parenchyma orders of magnitude greater than by systemic administration. Patients with recurrent glioma treated with individual fusion protein CED have obtained clinical remissions lasting years. However, toxicities to normal brain have been observed and relapses ultimately occurred. To address the clinical need of these patients and improve upon the therapeutic index observed to date with single fusion protein CED, we generated a novel fusion protein DAB389EGF and tested it in combination with another active fusion protein, IL13PE38QQR. We observed potent glioma cytotoxicity with each fusion protein and synergistic toxicity with the combination. Further, brain tumor cells showed heterogeneous expression of individual receptors suggesting that the combination--DAB389EGF and IL13PE38QQR may show improved efficacy and should undergo further preclinical development for therapy of patients with relapsed high-grade gliomas.

Brain Neoplasms↗
PubMed2003

Interleukin-4-Pseudomonas exotoxin chimeric fusion protein for malignant glioma therapy.

Human malignant glioma cell lines, primary cell cultures, and tumor specimens derived from surgical samples have been shown to overexpress high-affinity receptors (R) for interleukin-4 (IL-4) in vitro and in situ. The significance of IL-4R expression on malignant glioma cells is still unclear. However, IL-4 has been reported to mediate functional effects in several solid tumor cell lines. These activities include inhibition of cell proliferation, regulation of adhesion molecules, and induction of signal transduction through the JAK/STAT pathway. To target IL-4Rs on tumor cells, we have produced a chimeric recombinant fusion protein consisting of a binding ligand, circularly permuted IL-4 and a mutated form of Pseudomonas exotoxin. This molecule is termed IL4(38-37)-PE38KDEL, cpIL4-PE, or IL-4 cytotoxin. Recombinant cpIL4-PE is highly and specifically cytotoxic to glioma cell lines in vitro, while it is not cytotoxic or less cytotoxic to hematopoietic and normal brain cells. In a nude mouse model, cpIL4-PE showed significant antitumor activity and partial or complete regression of small or large established human glioblastoma tumors. Encouraging preclinical efficacy, safety, and tolerability studies lead to testing of this agent in patients with recurrent glioblastoma. Based on these pilot studies, an extended Phase I/II clinical trial is currently ongoing to determine safety, tolerability, and efficacy of cpIL4-PE when injected stereotactically directly into the recurrent glioma by convection enhanced delivery. Preliminary clinical results suggest that cpIL4-PE can cause pronounced necrosis of recurrent glioma tumors without systemic toxicity. The central nervous system toxicities observed were attributed to the volume of infusion and/or nonspecific toxicity. Ongoing clinical trials will reveal antitumor activities of IL-4 cytotoxin in recurrent malignant glioma.

Animals↗
PubMed2003

DAB389EGF fusion protein therapy of refractory glioblastoma multiforme.

Primary brain tumors including anaplastic astrocytomas and glioblastoma multiforme are difficult to treat because of their locally invasive nature and chemoradioresistance. Novel therapies are needed. One class of therapeutics is fusion proteins consisting of peptide toxins fused to brain tumor selective ligands. DAB389EGF is a fusion protein composed of the catalytic and translocation domains of diphtheria toxin fused via a His-Ala linker to human epidermal growth factor (EGF). DAB389EGF is selectively toxic to EGF receptor (EGFR) overexpressing cells. Close to half of all high-grade primary brain tumors have EGFR gene amplification and EGFR overexpression. With the use of convection-enhanced delivery (CED), DAB389EGF may be delivered locally at high concentrations to the brain tumor. CED would avoid many of the pharmacologic and toxicologic barriers which have limited effective use of this agent including rapid clearance from the circulation, high anti-diphtheria toxin antibody titers in the blood and toxicities to the liver and kidney. Both cell lines and animal models are available to assess the potential of this agent for brain tumor therapy. Since significant amounts of clinical grade DAB389EGF are available, some careful additional preclinical efficacy work should lead to testing of this agent in patients within the next few years.

Animals↗
PubMed2003

Interleukin-4 receptor-targeted cytotoxin therapy of androgen-dependent and -independent prostate carcinoma in xenograft models.

Prostate cancer is the most commonly diagnosed solid tumors in United States men. Survival with advanced prostate cancer is dismal because of a lack of effective treatments. Overexpression of interleukin 4 receptors (IL-4R) on prostate carcinoma cells makes them suitable targets for the interleukin 4 (IL-4) fused Pseudomonas exotoxin, IL-4 cytotoxin (IL4-CTx). Androgen-dependent (LNCaP) and -independent (DU145) human prostate cancer cell lines overexpress IL-4Rs and are exquisitely sensitive to IL4-CTx. Using LNCaP and DU145 cell lines, IC(50) values of 4.5 +/- 2.0 and 6.5 +/- 0.5 ng/ml, respectively, were obtained for IL4-CTx in protein synthesis inhibition assays. Primary cultures established from prostate tumor biopsies were equally sensitive to the cytotoxic effects of IL4-CTx. Reverse transcription-PCR analysis, although not quantitative, indicated the presence of mRNA for IL-4Ralpha, a primary subunit of the IL-4R receptor complex in prostate carcinoma cell lines, primary cultures, benign prostatic hyperplasia, and prostate carcinoma tissues. Immunohistochemistry studies revealed the presence of IL-4R in benign prostatic hyperplasia and prostate carcinomas. Five daily (QD) injections of IL4-CTx (100 micro g/kg) administered i.v., i.p., or intratumoral (i.t.) caused several complete responses in nude mice with s.c. DU145 and LNCaP tumors. i.t. injections of IL4-CTx elicited tumor regression in a dose-dependent manner with complete responses occurring in 100% of the animals when treated with IL4-CTx (500 micro g/kg) given five QD injections. Administration of IL4-CTx i.t. (500 micro g/kg) either 10 times QD or six injections on alternate days elicited complete responses in 40% of mice with DU145 tumors that were three times larger (67 mm(2)) on initiation of treatments. IL4-CTx appeared to be well tolerated. On the basis of these results, combining i.t. injections of IL4-CTx with systemic administration may provide an effective strategy for treating patients with advanced, refractory prostate cancer.

Animals↗
PubMed2003

Effect of interleukin (IL)-4 cytotoxin on breast tumor growth after in vivo gene transfer of IL-4 receptor alpha chain.

Although human breast cancer cells express interleukin-4 receptors (IL-4Rs), a recombinant fusion protein, IL-4 cytotoxin, did not mediate desirable antitumor activity in tumor models of breast cancer. Recent studies have identified that a primary IL-4 binding protein, IL-4Ralpha chain, is internalized after binding to IL-4 in cancer cells. The consequent expression of high-level IL-4Ralpha in tumor cells sensitizes them to the cytotoxic effect of IL-4 cytotoxin in vitro. To assess whether overexpression of IL-4Ralpha chain in vivo by plasmid-mediated gene transfer can enhance antitumor activity of IL-4 cytotoxin in mouse models of breast tumor, we injected MDA-MB-231 human breast cancer cells in both flanks of athymic nude mice. Animals then received three intratumoral (i.t.) injections of either IL-4Ralpha encoding vector (left flank) or vector only (right flank) mixed with liposome followed by IL-4 cytotoxin administration. Both i.p. and i.t. administration of IL-4 cytotoxin profoundly reduced the growth of IL-4Ralpha plasmid-injected MDA-MB-231 tumors, compared with control. Innate immune cells, including macrophages and neutrophils, were found to infiltrate at the regressing tumor site. This study provides proof of principle that i.t. IL-4Ralpha plasmid injection followed by systemic or i.t. IL-4 cytotoxin administration may be a useful strategy for the treatment of breast cancer.

Animals↗
PubMed2003

Identification and characterization of interleukin-13 receptor in human medulloblastoma and targeting these receptors with interleukin-13-pseudomonas exotoxin fusion protein.

AIM: To identify and characterize the subunit structure of interleukin-13 receptor (IL-13R) in human medulloblastoma cell lines and target them with a chimeric fusion protein consisting of interleukin-13 and Pseudomonas exotoxin (termed as IL-13 cytotoxin). METHODS: Five human medulloblastoma cell lines were examined for the expression of IL-13R subunits at the mRNA and protein levels by reverse transcriptase-polymerase chain reaction (RT-PCR) and indirect immunofluorescence studies, respectively. In addition, IL-13 cytotoxin-induced cytotoxicity was examined in these medulloblastoma cell lines by measuring protein synthesis inhibition. RESULTS: All five medulloblastoma cell lines expressed mRNA and proteins for IL-4Ra and IL-13Ra1 chains, whereas three of the cell lines also showed the presence of IL-13Ra2. mRNA or protein for IL-2gc chain was not detected in any of the cell lines. Consistent with the expression of IL-13Ra2 chain, IL-13 cytotoxin was highly and specifically cytotoxic to three of five medulloblastoma cell lines. The sensitivity of medulloblastoma cell lines to IL-13 cytotoxin could be completely eliminated by concurrent incubation with excess of IL-13, but not with IL-2 or IL-4. CONCLUSION: These studies establish IL-13R, in particular IL-13Ra2, as a medulloblastoma-associated target for IL-13 cytotoxin therapy. IL-13 cytotoxin may be useful for medulloblastoma therapy. Alternatively, IL-13Ra2 may serve as a tumor-specific antigen for active immunotherapy.

Cerebellar Neoplasms↗