Cho-Lea Tso

Interleukin-6 and renal cell cancer : production, regulation, and growth effects

SummaryInterleukin-6 (IL-6) is a recently characterized pleiotropic cytokine with antitumor activity. We investigated the production of IL-6 by renal cell cancer (RCC) and the growth effects of IL-6 on RCC. Using immunoperoxidase staining, cytoplasmic IL-6 was detected in four of four renal tumor lines and in tumor cells from freshly nephrectomized RCC. We found that IL-6 mRNA was expressed at basal culture conditions by seven of ten RCC tumor lines tested. Biologically active IL-6, as measured by the B9 assay, was produced by all ten RCC tumor lines. The addition of tumor necrosis factor α (TNFα) significantly augmented the expression of IL-6 mRNA in five RCC tumor lines (P <0.05). The combination of interferon γ IFNγ and TNFα further enhanced the augmented IL-6 mRNA accumulation seen with TNFα alone (P <0.05). TNFα also significantly stimulated the production of biologically active IL-6 (P <0.01). Furthermore, IFNγ and TNFα were found to enhance IL-6 bioactivity synergistically (P <0.05). The growth effects of IL-6 on RCC were also investigated in two experimental systems: IL-6 was found to stimulate proliferative responses in six of six RCC tumor lines as measured by thymidine-uptake assays; however, only one of six tumor lines displayed an increase in proliferative response of greater than 21% (113%). The growth effect of IL-6 was further tested in clonogenic assays. One of the tumor lines tested displayed an enhanced growth response of up to 200%. We conclude that IL-6 is produced by RCC; this production is enhanced by TNFα with synergistic effects seen with IFNγ at both mRNA and protein levels. In turn, IL-6 may have a modest stimulatory growth effect on certain RCC tumor lines.

Molecular properties of CD133+ glioblastoma stem cells derived from treatment-refractory recurrent brain tumors

Glioblastoma multiforme (GBM) remains refractory to conventional therapy. CD133+ GBM cells have been recently isolated and characterized as chemo-/radio-resistant tumor-initiating cells and are hypothesized to be responsible for post-treatment recurrence. In order to explore the molecular properties of tumorigenic CD133+ GBM cells that resist treatment, we isolated CD133+ GBM cells from tumors that are recurrent and have previously received chemo-/radio-therapy. We found that the purified CD133+ GBM cells sorted from the CD133+ GBM spheres express SOX2 and CD44 and are capable of clonal self-renewal and dividing to produce fast-growing CD133− progeny, which form the major cell population within GBM spheres. Intracranial injection of purified CD133+, not CD133− GBM daughter cells, can lead to the development of YKL-40+ infiltrating tumors that display hypervascularity and pseudopalisading necrosis-like features in mouse brain. The molecular profile of purified CD133+ GBM cells revealed characteristics of neuroectoderm-like cells, expressing both radial glial and neural crest cell developmental genes, and portraying a slow-growing, non-differentiated, polarized/migratory, astrogliogenic, and chondrogenic phenotype. These data suggest that at least a subset of treated and recurrent GBM tumors may be seeded by CD133+ GBM cells with neural and mesenchymal properties. The data also imply that CD133+ GBM cells may be clinically indolent/quiescent prior to undergoing proliferative cell division (PCD) to produce CD133− GBM effector progeny. Identifying intrinsic and extrinsic cues, which promote CD133+ GBM cell self-renewal and PCD to support ongoing tumor regeneration may highlight novel therapeutic strategies to greatly diminish the recurrence rate of GBM.

Interleukin 2 gene therapy for prostate cancer : Phase I clinical trial and basic biology

Twenty-four patients with locally advanced prostate cancer (CaP) were enrolled in a phase I clinical trial using gene-based immunotherapy. A functional DNA-lipid complex encoding the interleukin 2 (IL-2) gene (Leuvectin; Vical, San Diego, CA) was administered intraprostatically into the hypoecogenic tumor lesion, using transrectal ultrasound guidance. Two groups of patients having locally advanced tumors were enrolled to receive a treatment regimen composed of two serial intraprostatic injections of the IL-2 gene agent administered 1 week apart. The first groups of patients included radical prostatectomy candidates who subsequently underwent surgery after the completion of the treatment regimen. The second group consisted of patients who had failed a prior therapy. Prostate specimens of the treated areas were attained after treatment and compared with the transrectal biopsies performed at baseline to assess for any responses. IL-2 gene therapy was well tolerated, with no grade 3 or 4 toxic reactions occurring. The most commonly reported symptoms were mild hematuria, transient rectal bleeding, and perineal discomfort that are likely attributable to the injection itself. During the entire course of treatment, there were no significant changes in American Urologic Association (AUA) symptom scores, in hematologic disturbances, electrolyte imbalances, or hepatic functions. Evidence of systemic immune activation was observed after IL-2 gene therapy, based on an increase in the intensity of T cell infiltration seen on immunohistochemical analysis of tissue samples from the injected tumor sites, and based on increased proliferation rates of peripheral blood lymphocytes that were cocultured with patient serum collected after treatment. Furthermore, transient decreases in serum prostate-specific antigen (PSA) (responders) were seen in 16 of 24 patients (67%) on day 1. Fourteen of the patients persisted in this decrease to day 8 (58%). In eight patients the PSA level rose (nonresponders). More patients (9 to 10) in the group that failed prior therapy responded to the IL-2 gene injections (chi-square test, p = 0.04), and 6 of the 9 also had lower than baseline PSA levels at week 10 after treatment. To the best of our knowledge, this is the first clinical study of its kind aimed at exploring the role of IL-2-based gene therapy in CaP patients. This phase I trial demonstrated the safety of intraprostatic Leuvectin injection, with transient PSA-based responses seen after therapy.

A pilot trial of tumor lysate-loaded dendritic cells for the treatment of metastatic renal cell carcinoma.

Cultured tumor lysate-loaded dendritic cells (TuLy-DC) have been demonstrated in vitro to stimulate potent immune modulations and generate significant antitumor response. We report the results of a pilot trial of TuLy-DC vaccine for patients with metastatic renal cell carcinoma (mRCC). Fourteen mRCC patients underwent nephrectomy to obtain autologous TuLy prepared by subjecting tumor cells to 3 freeze/thaw cycles. Dendritic cells were generated from peripheral blood CD14+ precursors cultured in the presence of GM-CSF, IL-4, and 10% autologous serum. Patients received one vaccination of TuLy alone as an immunologic control, followed by 3 weekly vaccinations of DC-TuLy injected intradermally in the midaxillary region. Peripheral blood lymphocytes were collected before and after weekly vaccines and were assessed for changes in phenotype, cytotoxicity, and cytokine profile. The TuLy-DC vaccine was successfully prepared and administered to 12 patients, whereas 2 patients did not receive vaccine treatment due to declines in postoperative performance status. The vaccines were well tolerated, with only grade 1 toxicities noted. One patient had a partial response to treatment that did not correspond to any significant change in immunologic profile. This pilot trial demonstrated both the safety and feasibility of reliably preparing a DC-based vaccine for mRCC patients. Our data suggest that autologous TuLy-DC vaccines generate only limited clinical response. Further clinical studies are needed to identify the most potent treatment regimen that can consistently mediate an antitumor immune response in vivo.

Relationship between Survival and Edema in Malignant Gliomas: Role of Vascular Endothelial Growth Factor and Neuronal Pentraxin 2

Purpose: Vascular endothelial growth factor (VEGF) is a potent mediator of vascular permeability. VEGF inhibition reduces edema and tumor burden in some patients with malignant glioma, whereas others show no response. The role of VEGF expression in edema production and the relationship to survival is not well understood. Experimental Design: Using DNA microarray analysis, we examined VEGF and related gene expression in 71 newly diagnosed malignant gliomas and analyzed the relationship to edema and survival. Results and Conclusions: VEGF expression was predictive of survival in tumors with little or no edema [Cox proportional hazard model, 6.88; 95% confidence interval (95% CI), 2.61-18.1; P < 0.0001], but not in tumors with extensive edema. The expression of several proangiogenic genes, including adrenomedullin (correlation coefficient, 0.80), hypoxia-inducible factor-1A (0.51), and angiopoietin-2 (0.44), was correlated with VEGF expression (all with P < 0.0001), whereas that of several antiangiogenic genes was inversely correlated. The expression of six genes was increased greater than 3-fold in edematous versus nonedematous tumors in the absence of increased VEGF expression. The most increased, neuronal pentraxin 2 (NPTX2, 7-fold change), was predictive of survival in tumors with the highest levels of edema, in contrast to VEGF (hazard ratio, 2.73; 95% CI, 1.49-5.02; P = 0.049). NPTX2 was tightly correlated with expression of the water channel aquaporin-3 (0.74, P < 0.0001). These results suggest that there are both VEGF-dependent and VEGF-independent pathways of edema production in gliomas and may explain why edema is not reduced in some patients following anti-VEGF treatment.

Interferon-α Primed Tumor-Infiltrating Lymphocytes Combined with Interleukin-2 and Interferon-α as Therapy for Metastatic Renal Cell Carcinoma

AbstractMurine models demonstrate therapeutic synergy for the combination of interleukin-2, interferon-α and tumor-infiltrating lymphocytes. We treated 11 patients with metastatic renal cell carcinoma with a novel regimen consisting of in vivo primed tumor-infiltrating lymphocytes, interferon-α and interleukin-2. Patients received interferon-α before radical nephrectomy; in vivo primed tumor-infiltrating lymphocytes were isolated and expanded in vitro. Low dose continuous infusion inter-leukin-2 at a dose of 2 × 106 units per m2 per day was administered for 96 hours during each treatment week and interferon-α was administered as a subcutaneous injection at a dose of 6 × 106 units per m.2 per day on days 1 and 4 of the interleukin-2 infusion. No therapy was given during the last 3 days of a treatment week. One course of therapy consisted of 3 weeks of therapy followed by 3 weeks of rest. Patients were treated until maximal response, disease progression or dose limiting toxicity. A maximum of 6 courses of t...

Phase I trial of antigen-specific gene therapy using a recombinant vaccinia virus encoding MUC-1 and IL-2 in MUC-1-positive patients with advanced prostate cancer.

Abstract: MUC-1 is overexpressed on many tumor cells. In addition, aberrant glycosylation of MUC-1 on human tumors leads to exposure of cryptic peptide epitopes that play a role in tumor immunity. As such, it has been identified as a potential target for immunotherapy. The purpose of this phase 1 clinical trial was to determine the maximum tolerated dose, safety of a multiple-dose regimen, and the immunologic effect of vaccinia virus expressing MUC-1 and IL-2 genes (VV/MUC-1/IL-2) in patients with advanced prostate cancer. Five × 105, 5 × 106, and 5 × 107 plaque-forming units (pfu) of vaccinia viruses were used in the dose-escalating study. Viruses were given via intramuscular injection, and clinical response and immune function modulation were analyzed. No grade 3 or 4 toxicity was observed. Objective clinical response was observed after the fourth injection (0.3 ng/mL) in only one patient who received an intermediate dose of virus. Systemic immune modulation in this patient included (1) up-regulation of IL-2 (CD25) and T cell (TcR &agr;β) receptors, (2) increase in the CD4/CD8 ratio (2.5-fold) (3) augmentation of T-helper type 1 cell (TH1) (interferon-γ and tumor necrosis factor-&agr; ) but not TH2 (IL-4) cytokine mRNA expression, (4) induction of natural killer cell activity and MHC independent MUC-1 specific cytotoxic T-cell activity, and (5) normalization of mRNA expression of T-cell–associated signal transduction molecules TcR-ζ and p56lck. These results suggest that VV/MUC-1/IL-2 gene therapy with a maximum tolerated dose of 5 × 107 pfu is safe and well tolerated.

Autologous tumor-specific cytotoxicity of tumor-infiltrating lymphocytes derived from human renal cell carcinoma

Summary: Conditions for generating and expanding cytotoxic tumor-specific, tumor-infiltrating lymphocytes (TIL) were studied to improve the efficacy of adoptive cancer immunotherapy. Thus, we have examined the growth and cytolytic patterns of bulk culture TIL from human renal cell carcinoma (RCC) cultured in low (20 U/ml) or high (1,000 U/ml) dose interleukin (IL)-2, with or without irradiated autologous tumor stimulation. By 55 days in culture, TIL grown in the presence of IL-2 without tumor stimulation lost their lytic activity, whereas those exposed to tumor stimulation maintained high levels of cytotoxicity against autologous and/or nonautologous tumor targets. Only TIL grown with low dose IL-2 and autologous tumor maintained long-term (over 4 months in culture) specific cytotoxicity against the autologous tumor, even upon cryopreservation and regrowth. These TIL were 88-97% and 80% positive for CD3 and CD8, with a persistent subset exhibiting CD4+ CD8+ double positive staining. Their specific cytotoxic activity was major histocompatibility complex Class I-restricted and inhibited by pretreating the TIL with anti-CD3 monoclonal antibody. TIL exposed to the four types of culture conditions, low or high dose IL-2, with or without irradiated autologous tumors, and exhibiting different lytic specificities, all expressed mRNA for interferon-gamma and tumor necrosis factor (TNF)-alpha, but not for IL-1-beta, IL-4, IL-6, and granulocyte- macrophage colony stimulating factor. The degree of TNF-alpha mRNA expression correlated with the degree of autologous tumor-specific cytotoxicity of these TIL. This initial report demonstrates that antigen-specific cytotoxicity against the autologous tumor does, in fact, exist within the RCC tumors. Furthermore, by modifying culture conditions, cytotoxic T-lymphocytes with anti-tumor activity can be selectively grown from the heterogeneous bulk cultures of TIL.

CL1-GFP: an androgen independent metastatic tumor model for prostate cancer.

PURPOSE The mechanisms responsible for tumor progression to androgen independence in prostate cancer (CaP) remain unknown. To characterize these changes and provide a basis for rational therapeutic strategies for advanced CaP, an in vivo model from a highly aggressive androgen independent CaP cell line with distinct cellular and molecular properties was developed. MATERIALS AND METHODS An aggressive androgen-independent cell line designated CL1 was derived from a slow-growing, and androgen-dependent, parental LNCaP cell line through in-vitro androgen-deprivation and selection. CL1 was stably transfected with a green fluorescence protein gene (CL1-GFP) and orthotopically injected into SCID mice. The pathologic behavior, histology, and molecular determinants of CL1 tumor and metastases were determined and characterized by standard light and fluorescent microscopy, and quantitative RT-PCR analysis. RESULTS CL1 is an anaplastic prostate cancer cell line which demonstrates extensive local invasion and metastases to various organs that can be visualized via GFP expression. When compared with parental LNCaP cells, RT-PCR analysis of the tumor revealed an over-expression of EGFR, b-FGF, VEGF, TGF-beta, IL-8, IL-6, and bcl-2 and a down regulated expression of the p53, E-cadherin and PTEN. In contrast to LNCaP cells, CL1 tumors express lower levels of androgen receptor and barely detectable PSA mRNA. CONCLUSIONS CL1-GFP represents an aggressive androgen-independent CaP tumor model derived through androgen deprivation whose pathologic development and molecular properties in animals resembles the clinical characteristics of hormone refractory prostate cancer (HRPC). Metastatic sites of CL1-GFP can be visualized with fluorescence microscopy offering a unique therapeutic model for the evaluation of drug sensitivity and other therapeutic modalities.

Autocrine Endothelin-3/Endothelin Receptor B Signaling Maintains Cellular and Molecular Properties of Glioblastoma Stem Cells

Glioblastoma stem cells (GSC) express both radial glial cell and neural crest cell (NCC)-associated genes. We report that endothelin 3 (EDN3), an essential mitogen for NCC development and migration, is highly produced by GSCs. Serum-induced proliferative differentiation rapidly decreased EDN3 production and downregulated the expression of stemness-associated genes, and reciprocally, two glioblastoma markers, EDN1 and YKL-40 transcripts, were induced. Correspondingly, patient glioblastoma tissues express low levels of EDN3 mRNA and high levels of EDN1 and YKL-40 mRNA. Blocking EDN3/EDN receptor B (EDNRB) signaling by an EDNRB antagonist (BQ788), or EDN3 RNA interference (siRNA), leads to cell apoptosis and functional impairment of tumor sphere formation and cell spreading/migration in culture and loss of tumorigenic capacity in animals. Using exogenous EDN3 as the sole mitogen in culture does not support GSC propagation, but it can rescue GSCs from undergoing cell apoptosis. Molecular analysis by gene expression profiling revealed that most genes downregulated by EDN3/EDNRB blockade were those involved in cytoskeleton organization, pause of growth and differentiation, and DNA damage response, implicating the involvement of EDN3/EDNRB signaling in maintaining GSC migration, undifferentiation, and survival. These data suggest that autocrine EDN3/EDNRB signaling is essential for maintaining GSCs. Incorporating END3/EDNRB-targeted therapies into conventional cancer treatments may have clinical implication for the prevention of tumor recurrence. Mol Cancer Res; 9(12); 1668–85. ©2011 AACR.