Sodium iodide symporter (NIS)-mediated radiovirotherapy of hepatocellular cancer using a conditionally replicating adenovirus.

In this study, we determined the in vitro and in vivo efficacy of sodium iodide symporter (NIS) gene transfer and the therapeutic potential of oncolytic virotherapy combined with radioiodine therapy using a conditionally replicating oncolytic adenovirus. For this purpose, we used a replication-selective adenovirus in which the E1a gene is driven by the mouse alpha-fetoprotein (AFP) promoter and the human NIS gene is inserted in the E3 region (Ad5-E1/AFP-E3/NIS). Human hepatocellular carcinoma cells (HuH7) infected with Ad5-E1/AFP-E3/NIS concentrated radioiodine at a level that was sufficiently high for a therapeutic effect in vitro. In vivo experiments demonstrated that 3 days after intratumoral (i.t.) injection of Ad5-E1/AFP-E3/NIS HuH7 xenograft tumors accumulated approximately 25% ID g(-1) (percentage of the injected dose per gram tumor tissue) (123)I as shown by (123)I gamma camera imaging. A single i.t. injection of Ad5-E1/AFP-E3/NIS (virotherapy) resulted in a significant reduction of tumor growth and prolonged survival, as compared with injection of saline. Combination of oncolytic virotherapy with radioiodine treatment (radiovirotherapy) led to an additional reduction of tumor growth that resulted in markedly improved survival as compared with virotherapy alone. In conclusion, local in vivo NIS gene transfer using a replication-selective oncolytic adenovirus is able to induce a significant therapeutic effect, which can be enhanced by additional (131)I application.

An unusual case of ectopic ACTH syndrome.

Ectopic ACTH-syndrome is a rare cause of Cushing's disease. Despite extensive diagnostic procedures the source of ACTH secretion often remains occult. This case describes a 45-year old woman with an ectopic Cushing's syndrome. Extensive imaging procedures including CT scan of chest and abdomen, octreotide scan and MRI of the chest and pituitary did not reveal the source of ACTH secretion. In consideration of an occult source of ACTH secretion we started a therapeutic trial with cabergoline (0.5 mg/d), a dopamine receptor agonist, which has been shown to be effective in ectopic Cushing's syndrome. 2 months after cabergoline treatment had been initiated, ACTH and cortisol levels normalized in association with significant improvement of the clinical symptoms. During follow-up a [(68)Ga-DOTA-dPhe(1), Tyr(3)]-octreotate ([(68)Ga-DOTA]-TATE) PET-CT was performed revealing a somatostatin receptor positive lesion in the right sphenoidal sinus suggesting the source of ACTH secretion. The patient was cured by transnasal resection of the polypoid lesion, which was immunohistochemically characterized as an ACTH-positive neuroendocrine tumor. This case report demonstrates the management of ectopic ACTH-syndrome by molecularly -targeted therapy with dopamine receptor -agonists as well as improved detection of the ectopic ACTH source by novel imaging modalities, such as [(68)Ga-DOTA]-TATE PET specifically targeting somatostatin receptor subtype-2 with high affinity.

Alpha-fetoprotein promoter-targeted sodium iodide symporter gene therapy of hepatocellular carcinoma.

Due to limited treatment options the prognosis of patients with advanced hepatocellular cancer (HCC) has remained poor. To investigate an alternative therapeutic approach, we examined the feasibility of radioiodine therapy of HCC following human sodium iodide symporter (NIS) gene transfer using a mouse alpha-fetoprotein (AFP) promoter construct to target NIS expression to HCC cells. For this purpose, the murine Hepa 1-6 and the human HepG2 hepatoma cell lines were stably transfected with NIS cDNA under the control of the tumor-specific AFP promoter. The stably transfected Hepa 1-6 cell line showed a 10-fold increase in iodide accumulation, while HepG2 cells accumulated (125)I approximately 60-fold. Tumor-specific NIS expression was confirmed on mRNA level by northern blot analysis, and on protein level by immunostaining, that revealed primarily membrane-associated NIS-specific immunoreactivity. In an in vitro clonogenic assay up to 78% of NIS-transfected Hepa 1-6 and 93% of HepG2 cells were killed by (131)I exposure, while up to 96% of control cells survived. In vivo NIS-transfected HepG2 xenografts accumulated 15% of the total (123)I administered per gram tumor with a biological half-life of 8.38 h, resulting in a tumor absorbed dose of 171 mGy MBq(-1) (131)I. After administration of a therapeutic (131)I dose (55.5 MBq) tumor growth of NIS expressing HepG2 xenografts was significantly inhibited. In conclusion, tumor-specific iodide accumulation was induced in HCC cells by AFP promoter-directed NIS expression in vitro and in vivo, which was sufficiently high to allow a therapeutic effect of (131)I. This study demonstrates the potential of tumor-specific NIS gene therapy as an innovative treatment strategy for HCC.

Dexamethasone stimulation of retinoic Acid-induced sodium iodide symporter expression and cytotoxicity of 131-I in breast cancer cells.

CONTEXT: The sodium iodide symporter (NIS) mediates the active iodide uptake in the thyroid gland as well as lactating breast tissue. Recently induction of functional NIS expression was reported in the estrogen receptor-positive human breast cancer cell line MCF-7 by all-trans retinoic acid (atRA) treatment in vitro and in vivo, which might offer the potential to treat breast cancer with radioiodine. OBJECTIVE: In the current study, we examined the effect of dexamethasone (Dex) on atRA-induced NIS expression and therapeutic efficacy of 131-I in MCF-7 cells. DESIGN: For this purpose, NIS mRNA and protein expression levels in MCF-7 cells were examined by Northern and Western blot analysis after incubation with Dex (10(-9) to 10(-7) m) in the presence of atRA (10(-6) m) as well as immunostaining using a mouse monoclonal human NIS-specific antibody. In addition, NIS functional activity was measured by iodide uptake and efflux assay, and in vitro cytotoxicity of 131-I was examined by in vitro clonogenic assay. RESULTS: After incubation with Dex in the presence of atRA, NIS mRNA levels in MCF-7 cells were stimulated up to 11-fold in a concentration-dependent manner, whereas NIS protein levels increased up to 16-fold and iodide accumulation was stimulated up to 3- to 4-fold. Furthermore, iodide efflux was modestly decreased after stimulation with Dex in the presence of atRA. Furthermore, in the in vitro clonogenic assay, selective cytotoxicity of 131-I was significantly increased from approximately 17% in MCF-7 cells treated with atRA alone to 80% in MCF-7 cells treated with Dex in the presence of atRA. CONCLUSION: Treatment with Dex in the presence of atRA significantly increases functional NIS expression levels in addition to inhibiting iodide efflux, resulting in an enhanced selective killing effect of 131-I in MCF-7 breast cancer cells.

Reliability of PCR-based detection of occult tumour cells: lessons from real-time RT-PCR.

For the molecular detection of rare tumour cells in clinical samples, real-time reverse transcription-polymerase chain reaction (RT-PCR) offers two important advantages over conventional RT-PCR assays: the results are quantitative and, perhaps more importantly, it facilitates exact sensitivity controls on a per sample basis as well as exact comparison of different assay protocols. We report here on quantitative results obtained with different protocols for RNA isolation and cDNA synthesis for amplification of beta2-microglobulin transcripts using the light cycler system. Furthermore, housekeeping gene-specific PCRs were compared with PCRs specific for an artificial transcript (internal standard) detected simultaneously at a level comparable to the wild-type sequence. Artificial tyrosinase transcripts derived from a vector construct stably transfected into a human lymphoma cell line were used as a model to test the usefulness of artificial internal standards as an alternative to housekeeping genes. The highest RNA yields were obtained using a combination of phenol-chloroform extraction and the High Pure RNA Isolation Kit. Analysing beta2-microglobulin transcript-specific RT-PCRs, the highest sensitivity was obtained for cDNAs generated with Omniscript reverse transcriptase and oligo-p(dT)15 primer. Regarding patient blood samples, RT-PCRs specific for beta2-microglobulin, porphobilinogen deaminase and artificial tyrosinase transcripts provided quantitative data for all, for 18 out of 21, and for 10 out of 21 samples, respectively. Quantification of beta2-microglobulin transcripts by the light cycler system defined the protocol revealing the highest cDNA quality. Comparisons of quantitative data from RT-PCRs specific for beta2-microglobulin, porphobilinogen deaminase and artificial tyrosinase transcripts enabled us to determine a close range for crossing points within which sufficient cDNA quality can be guaranteed, even for the detection of rare transcripts. PCRs specific for the artificial internal standard are ideally suited for cDNA quality assessment on a per sample basis.

Loss of collagen type IV in rheumatoid synovia and cytokine effect on the collagen type-IV gene expression in fibroblast-like synoviocytes from rheumatoid arthritis.

Collagen type IV is a structural matrix protein which contributes to the structural organization of the synovia. In order to characterize the distribution of this protein in synovia with chronic synovitis, collagen type IV was detected by immunochemistry in normal synovia and in synovia from patients with osteoarthritis (OA) and rheumatoid arthritis (RA). A decrease of collagen type IV was observed in synovial layers of rheumatoid synovia, which statistically correlated with the grade of inflammation and with the thickness of the synovial layer. In vitro, we found no differences in the gene expression of collagen type IV in cultures of fibroblast-like synoviocytes (FLS) derived from OA and RA using a reverse-transcriptase polymerase chain reaction. Nevertheless, we observed a downregulating effect of tumor necrosis factor-alpha and interleukin (IL)-1beta on the gene expression of collagen type IV only in FLS isolated from patients with RA. The effect of IL-1beta was dose dependent. In summary, we observed an inflammation-associated decrease of collagen type IV in the synovial layer of rheumatoid synovia. Inflammatory cytokines may play a role in regulating the synthesis of collagen type IV in the rheumatoid process in vivo.

Reliability of reverse transcription-polymerase chain reaction (RT-PCR)-based assays for the detection of circulating tumour cells: a quality-assurance initiative of the EORTC Melanoma Cooperative Group.

Reverse transcription-polymerase chain reaction (RT-PCR)-based assays detecting occult neoplastic cells are increasingly being used for the study of tumour dissemination and minimal residual disease. However, different methods are employed by various research groups and the results are heterogenous. We prospectively assessed the results from nine laboratories performing tyrosinase RT-PCR assays for the detection of melanoma cells on a series of blind samples. After complete analysis, the results were compared for sensitivity and specificity. All laboratories reported correct results for cDNA standards. Five laboratories attained acceptable specificity and a sensitivity detecting 10 cells in 10 ml of whole blood. Four laboratories had unacceptable specificity and/or sensitivity. This blind study highlights the difficulty of RT-PCR data interpretation and the need for quality assurance between laboratories. Measures to increase the reliability of RT-PCR assays are proposed, which have to be prospectively evaluated in future studies.

Polymerase chain reaction detection of circulating tumour cells. EORTC Melanoma Cooperative Group, Immunotherapy Subgroup.

Reverse transcriptase polymerase chain reaction (RT-PCR)-based assays to detect occult neoplastic cells offer the highest sensitivity for the study of tumour dissemination and minimal residual disease. The detection of small numbers of tumour cells in a clinical sample may result in a redefinition of what constitutes residual disease and relapse, affecting future patient management. However, there remains disparity in the published data on the clinical value of RT-PCR for the detection of circulating tumour cells. This most likely reflects differences in the methods for sample preparation, RNA extraction, and cDNA synthesis among laboratories. Consequently the need for implementation of standard quality control measures is pressing in order to facilitate meaningful assessment of the methodology and it's clinical value. A 2-day workshop organized by the immunotherapy subgroup of the EORTC Melanoma Cooperative Group was held on this topic at the Ludwig Institute in Epalinges-sur-Lausanne, Switzerland in January 1996, with Stefan Carrel as the local host. Many pertinent issues were discussed in great detail, covering every step from sample handling to quality control. This workshop resulted in a concerted action leading to the preparation of laboratory guidelines, which are summarized in this review.

Analysis of the T cell response to tumor and viral peptide antigens by an IFNgamma-ELISPOT assay.

We have established a sensitive ELISPOT assay measuring interferon gamma (IFN gamma) release on a single-cell basis to detect influenza peptide-specific CD8+ T cells in uncultured peripheral blood mononuclear cells (PBMC). Using this method, we studied the T cell response to HLA-A1 and HLA-A2.1 binding peptide epitopes derived from the MAGE-1 and MAGE-3 proteins, from the melanoma-associated antigens tyrosinase, Melan-A/MART-1 and gp100, and from influenza proteins in stage IV melanoma patients and healthy controls. In 18 of 24 HLA-A2-positive donors (75%), but only in 9 of 25 HLA-A2-positive melanoma patients (36%) T cells reactive with the influenza matrix peptide were demonstrated (p = 0.007). T cells responding to one or several of the melanoma-associated peptides were detected in 5 of 25 HLA-A2-positive patients with metastatic melanoma. Four of these 5 patients had been treated with interleukin-2- and IFN alpha-containing therapy. Two of the 24 healthy donors had T cells reactive with the MART-1 27-35 peptide. No reactivity with the HLA-A1-binding peptides from MAGE-1 or MAGE-3 was detected in any of the HLA-A1-positive healthy controls or melanoma patients. These results show that the IFN gamma-ELISPOT assay is suitable to determine quantitatively T cells reactive with melanoma-associated and influenza peptide epitopes in uncultured PBMC. The failure to detect T cells responding to influenza in many melanoma patients with progressive disease may indicate an impairment of their T cell function.

Detection of clonally rearranged T-cell-receptor gamma chain genes from T-cell malignancies and acute inflammatory rheumatic disease using PCR amplification, PAGE, and automated analysis.

Clonal expansions of T cells carrying identical T-cell-receptor (TCR) genes are the hallmark of T-cell malignancies, but they can also result from a strong immune reaction to a dominant epitope. The basis for the molecular detection of clonal T cells is amplification of the V-(D)-N-J region of the TCR gene. We evaluated PCR amplification of the rearranged gamma TCR from genomic DNA extracted from peripheral blood and subsequent polyacrylamide gel electrophoresis (PAGE) in an automated DNA sequencer. We determined the sensitivity for the detection of clonal T cells and propose a standardized evaluation procedure for the electrophoretic profiles generated by the DNA sequencer. The sensitivity of our method was 0.6-1.25% of clonal T cells within a polyclonal background. Sixteen patients with T-cell malignancies, ten with acute inflammatory rheumatic diseases, and twelve healthy controls were examined. Among the systemic T-cell malignancies, all but one patient with T-PLL (8/ 9) revealed a clonal PCR signal. No clonal signal was detectable in any patient in clinical complete remission (5/5) or in either of the two patients with lymphomas limited to cutaneous sites. However, clonal T cells were detected in one patient with polymyalgia rheumatica and in one with reactive arthritis. A polyclonal signal was found in the remaining eight patients with acute inflammatory rheumatic diseases and in 12 healthy controls. Taking our results together, the PCR/PAGE assay is able to reliably distinguish clonal from polyclonal T-cell populations. However, although the sensitivity is limited to approximately 1%, clonal T cells can be found in the peripheral blood of some patients with autoimmune diseases and not only in T-cell malignancies.

Expression of gp100 in melanoma metastases resected before or after treatment with IFN alpha and IL-2.

The melanosomal protein gp100 was recently described as an antigen associated with tumor rejection in adoptive immunotherapy using tumor-infiltrating lymphocytes. In this study, we investigated whether the expression of gp100 in melanoma cells correlates with responsiveness to treatment with interferon-alpha and interleukin-2. Using the monoclonal antibody HMB-45 recognizing gp100, we examined metastatic tissue resected before therapy in 44 patients with melanoma including 9 patients with subsequent complete or partial remission. A very heterogeneous pattern of gp100-expression was found between patients, but the percentage of gp-100 positive cells in different metastases resected from the same patient was rather constant. This suggests that the gp100 expression determined in a single metastasis may be judged as being representative for other metastatic lesions of a patient. We found no correlation between expression of gp100 and responsiveness to subsequent immunotherapy. Our results show that the lack of gp100 before therapy is not associated with decreased responsiveness to subsequent cytokine treatment.

Regulation of interleukin-8 mRNA expression and protein secretion in a melanoma cell line by tumour necrosis factor-alpha and interferon-gamma.

Interleukin-8 (IL-8) is a cytokine that is thought to promote melanoma tumour progression. We evaluated and adapted a non-radioactive, reverse transcriptase-polymerase chain reaction method for semiquantitative analysis of IL-8 mRNA expression. Using this technique we studied the regulation of IL-8 levels in the melanoma cell line Colo 38. Seeding of melanoma cells into culture dishes resulted in a significant increase of IL-8 expression, which could be attributed to adherence. A pronounced increase of IL-8 mRNA expression and protein production was induced by tumour necrosis factor-alpha (TNF alpha). Interferon-gamma (IFN gamma) partially inhibited TNF alpha-induced IL-8 secretion, whereas no influence on IL-8 mRNA levels was detected. The inhibitory affect of IFN gamma on melanoma cells is in contrast to its stimulatory effect on melanocytes.

T-cell receptor beta variable region diversity in melanoma metastases after interleukin 2-based immunotherapy.

Limited T-cell receptor (TCR) repertoire of tumor-infiltrating lymphocytes has been found in melanoma metastases and spontaneously regressing melanoma. Immunotherapy with INF-alpha/interleukin 2 can induce tumor regression in a proportion of patients with metastatic melanoma. We analyzed the gene expression of the TCR-beta variable (Vbeta) region of tumor-infiltrating lymphocytes from 16 melanoma metastases by subgroup-specific semiquantitative RNA PCR to investigate the influence of immunotherapy on the TCR pattern. In five progressing metastases before or after immunotherapy, no overexpression of Vbeta gene families was detectable, whereas in seven of seven metastases responding to IFN-alpha/interleukin 2 one to four Vbeta gene families were overexpressed. Preferential usage of certain Vbeta gene subgroups in patients sharing the same HLA class I molecules suggests a T-cell response to dominant public epitopes. Analysis of multiple specimens from the same patients gives evidence that this strong oligoclonal T-cell selection is induced or at least augmented by immunotherapy, supporting the functional relevance of this finding.

A polymerase chain reaction-based semiquantitative assessment of malignant melanoma cells in peripheral blood.

Malignant melanoma cells can be detected with high sensitivity in peripheral blood of patients using reverse transcription-PCR. The detection of tyrosinase mRNA that is actively expressed only in melanocytes and melanoma cells indicates the presence of melanoma cells in peripheral blood. As shown previously, tyrosinase transcripts can be found in a variety of patients with metastatic malignant melanoma. For semiquantitative analysis of these cells in peripheral blood and evaluation of possible influence of immunotherapy on the amount of circulating cells, we describe an assay combining reverse transcription-PCR and Southern blotting. In this system, the amount of circulating tumor cells was determined by interpolating the amplified tyrosinase signal strength of patient samples to an equivalent tyrosinase signal of diluted SK-mel 28 cells. We found that the amount of circulating tumor cells correlates with the tumor burden. Furthermore, in patients with regression of melanoma metastases after immunotherapy, a decrease of the amount of tumor cells in the peripheral blood was observed. Quantitative estimates of residual disease may be an accurate and sensitive predictor for the clinical course.

Restriction of T cell receptor V beta repertoire in melanoma metastasis responding to immunotherapy.

Restriction of the T cell receptor repertoire suggesting ongoing specific immune mechanisms has recently been described in melanoma tissue by several groups of investigators. The functional relevance for immunotherapy of melanoma, however, has not been established. We studied the T cell receptor repertoire in two melanoma metastases of a patient with a mixed response to immunotherapy. Expression of T cell receptor V beta regions was determined by subgroup-specific semiquantitative RNA polymerase chain reaction (PCR). In the regressing skin lesion a restricted expression of the T cell receptor repertoire and overexpression of three V beta subgroup genes was found; no restriction was present in the simultaneously progressing skin lesion of the same patient, compared with peripheral blood lymphocytes. Comparison of T cell receptor V beta gene expression in two metastatic lesions of a patient with simultaneously growing skin metastases, who did not receive immunotherapy, revealed only minor differences. These observations show for the first time an association between restricted T cell receptor repertoire and responsiveness of melanoma to immunotherapy and suggest a role of T cells using the overexpressed V beta genes for the cytokine-induced tumour regression.

[Normal synoviocytes and synoviocytes from osteoarthritis and rheumatoid arthritis bind extracellular matrix proteins differently]. / Normale Synoviozyten und Synoviozyten aus Osteoarthritis und rheumatoider Arthritis binden unterschiedlich an extrazelluläre Matrixproteine.

Extracellular matrix proteins are increased in inflammatory synovitis. We showed previously that the in situ expression of the corresponding extracellular matrix receptors (beta 1-integrins) is enhanced in synoviocytes (SC) of synovitis of different etiology (16). To investigate the adhesion of SC to extracellular matrix proteins, we examined the attachment of SC from normal and inflamed synovia to fibronectin, tenascin, laminin and collagen type IV. Compared to normal SC and SC of osteoarthritis, SC of rheumatoid arthritis showed an increased binding to tenascin, laminin, fibronectin and collagen type IV, suggesting a distinctive interaction of SC and extracellular matrix proteins in rheumatoid arthritis. Furthermore, the increased binding of SC of rheumatoid arthritis to extracellular matrix proteins may play a role in tissue remodelling associated with rheumatoid arthritis.

Detection of residual tumor cells in patients with malignant melanoma responding to immunotherapy.

Recently, a highly sensitive assay combining reverse transcription and polymerase chain reaction (PCR) to assess for melanoma cells in peripheral blood has been developed. Detection of tyrosinase mRNA, a tissue-specific enzyme in melanocytes and melanoma cells, indicates the presence of melanoma cells in peripheral blood. We examined blood samples and bone marrow aspirates from 28 patients with metastatic malignant melanoma for presence of melanoma cells prior to and after therapy with interferon (IFN)-alpha and interleukin (IL)-2. Ten patients showed antitumor response to immunotherapy, including three complete (CR) and seven partial remissions (PR). Four patients (three PR, one stable disease) underwent subsequent resection of residual tumor lesions and had no clinical evidence of disease after surgery. Tyrosinase mRNA was detected in blood and bone marrow samples from all patients with malignant melanoma prior to and after immunotherapy, including those with no clinical evidence of disease (median disease-free survival 21 months, range 19-28 months). Tyrosinase transcripts were also detected in all patients with amelanotic melanoma. In contrast, no tyrosinase mRNA was detectable in any of 30 healthy persons or in six patients with other malignancies. The presence of residual melanoma cells may be an important indicator of occurrence of delayed relapse.