HLA antigen expression and malignant mesothelioma

Comprehensive genomic profiling of pediatric peritoneal mesothelioma: case report with a literature review

Malignant peritoneal mesothelioma is an extremely rare and poorly recognized neoplasm in children. A 5-year-old boy presented with a 1-year history of progressive painless abdominal distension. A CT revealed a 19 × 19 × 11 cm3 cystic mass in the right hemiabdomen, without infiltrating the surrounding structures. The tumor was completely removed by surgery. The microscopic and immunohistochemical analyses confirmed peritoneal mesothelioma. Comprehensive genomic profiling revealed no major driving mutations including BAP1, no fusions, but with amplifications of AURKA, AURKC, HLA-1B, ZNF-217, OR5F1 and MEN1 genes. Imaging follow-up 3 months after surgery revealed metastatic disease. The patient died of pneumonia at another hospital shortly after the last follow-up examination at our institution. Pediatric peritoneal mesothelioma is an extremely rare malignancy with limited targeted options and a poor prognosis. Some of the identified molecular genomic biomarkers require further exploration and validation in this cancer.

IL-27 Mediates PD-L1 Expression and Release by Human Mesothelioma Cells

Malignant mesothelioma (MM) is a rare tumor with an unfavorable prognosis. MM genesis involves asbestos-mediated local inflammation, supported by several cytokines, including IL-6. Recent data showed that targeting PD-1/PD-L1 is an effective therapy in MM. Here, we investigated the effects of IL-6 trans-signaling and the IL-6-related cytokine IL-27 on human MM cells in vitro by Western blot analysis of STAT1/3 phosphorylation. The effects on PD-L1 expression were tested by qRT-PCR and flow-cytometry and the release of soluble (s)PD-L1 by ELISA. We also measured the concentrations of sPD-L1 and, by multiplexed immunoassay, IL-6 and IL-27 in pleural fluids obtained from 77 patients in relation to survival. IL-27 predominantly mediates STAT1 phosphorylation and increases PD-L1 gene and surface protein expression and sPD-L1 release by human MM cells in vitro. IL-6 has limited activity, whereas a sIL-6R/IL-6 chimeric protein mediates trans-signaling predominantly via STAT3 phosphorylation but has no effect on PD-L1 expression and release. IL-6, IL-27, and sPD-L1 are present in pleural fluids and show a negative correlation with overall survival, but only IL-27 shows a moderate albeit significant correlation with sPD-L1 levels. Altogether these data suggest a potential role of IL-27 in PD-L1-driven immune resistance in MM.

Malignant pleural mesothelioma--an update

Exposure to asbestos is the most frequent, but not exclusive, cause of malignant mesothelioma. Clinical features include dyspnea, cough, nonspecific chest pain, weight loss and night sweats. Diagnosis may be complicated by histologic difficulties. Thoracoscopic techniques are proving beneficial, but no one method of imaging has proven superior, and disease staging is inconsistent. Conventional treatments such as chemotherapy, surgery, and radiotherapy have had variable impacts, although chemotherapy is useful in palliation and can improve both survival and quality of life. There is hope for new antimetabolite agents. The role of radical surgery is yet to be evaluated in a large trial. New radiotherapeutic techniques to improve local control are promising. Multimodality treatments appear to be the most successful for management of potentially resectable disease. It is likely that biological markers will improve accuracy in staging and prognosis. With new treatments based on better understanding of the biology of the disease, there is cautious optimism for the future for patients with malignant pleural mesothelioma.

New approaches for mesothelioma: biologics, vaccines, gene therapy, and other novel agents

Although malignant mesothelioma is not a classically immunogenic cancer, there is abundant evidence for immune recognition. The relative ease of obtaining tumor tissue makes mesothelioma ideal for studying surrogate biomarkers such as lymphocytic infiltration or expression of transduced genes. There is evidence that malignant mesothelioma patients as well as asbestos-exposed persons without mesothelioma have impaired immune responsiveness. Substantial progress has been made in animal models using several biological and immunological techniques, but clinical application has been problematic. Systems studied have included lysis by interleukin-2 (IL-2)-activated lymphokine-activated killer (LAK) cells, tumor necrosis factor-alpha (TNF-alpha), a p16-expressing adenovirus vector, suicide gene therapy using the herpes simplex virus-tyrosine kinase (HSV-tk) followed by ganciclovir, and immunomodulatory gene therapy with IL-2, IL-4, interferon-gamma (IFN-gamma), IFN-alpha, TNF-alpha, granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, and IL-1beta transfected into tumors. Vaccinia virus has been studied as a vector for cytokine gene transfer. Suicide gene therapy has been combined with a tumor vaccine. The University of Western Australia is initiating a pilot study of autologous vaccination in malignant mesothelioma. Novel agents under study include the angiogenesis inhibitors SU5416, bevacizumab, and thalidomide. ZD1839, an orally administered, highly selective inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase, is being tested in a phase II trial. Since platelet-derived growth factor (PDGF) is thought to be an autocrine growth factor for mesothelioma STI-571 (Gleevec; Novartis, Basel, Switzerland), a highly selective inhibitor of the PDGF receptor tyrosine kinase, is being tested in a phase II trial. The development of more active cytotoxic combinations in this disease should facilitate further studies of chemoimmunotherapy. It seems likely that no single treatment modality will be effective by itself.

Primary human mesothelioma cells express class II MHC, ICAM-1 and B7-2 and can present recall antigens to autologous blood lymphocytes

Mesothelioma cells (MMc) are considered to be weakly immunogenic and the experimental approaches attempting to induce an immune response against these cells have been disappointing. Our aim was to investigate whether MMc possess the surface accessory molecules involved in antigen presentation and whether these cells are capable of presenting recall antigens to autologous blood lymphocytes. Four primary MMc cultures were generated from malignant effusions and examined to assess whether the accessory molecules required for antigen presentation were present on their surfaces. Intercellular adhesion molecule-I (ICAM-I; CD54); class I and class II major histocompatibility complex-DR (MHCI and MHCII-DR); B7-1 (CD80.3); and B7-2 (CD86) expression by MMc was studied by immunocytochemical and/or FACScan analysis. MMc were pulsed with purified protein derivative (PPD), Tetanus toxoid (TT) and Candida albicans (CA) bodies, and incubated with autologous lymphocytes. Lymphocyte proliferation was estimated by radionucleotide incorporation. Phenotypic analysis showed the presence of MHCII-DR, ICAM-I and B7-2 on primary MMc cultures, whereas the phenotypic evaluation of 2 established MMc lines did not show the presence of the B7-1 and B7-2 molecules. In addition, MHCII-DR was detectable only after interferon gamma (IFN-gamma) stimulation. Primary MMc cultures acquired the capability to induce lymphocyte proliferation after pulse with the recall antigens. To achieve characterization of these lymphocytes, we generated a PPD-specific CD4+ T-cell clone. PPD-pulsed MMc were shown to specifically induce T-cell clone proliferation through a MHCII-DR-mediated process. We conclude that primary MMc possess the surface molecules required for antigen presentation and can present recall antigens to CD4+ lymphocytes.

Weekly systemic combination of cisplatin and interferon alpha 2a in diffuse malignant pleural mesothelioma

The treatment of diffuse malignant pleural mesothelioma (DMPM) remains grim. Neither surgery, radiotherapy nor chemotherapy can be considered as a standard therapy. Immunotherapy with interferon (IFN) in combination with chemotherapy may be an interesting new approach. In 13 consecutive patients with DMPM, we used a weekly combination of cisplatin (CDDP) (60 mg/m2; day 2) and IFN alpha 2a (6 MU/day; days 1-4) in a protocol of two cycles of 4 weeks on/4 weeks off followed by 3 weeks on/3 weeks off. Total treatment duration was thus 25 weeks. In responders, IFN as maintenance monotherapy was continued for a further 6 months. There were nine males and four females with an average age of 65.3 years (range 51-72 years). Eleven had epithelial, one had mixed and one had a sarcomatoid form of DMPM. Five patients were classified as stage II, six as stage III and two as stage IV, as per the International Mesothelioma Interest Group. Thirty-five cycles were administered with a median of three cycles/patient (range 0.75-4). The median total cumulative dose of CDDP was 596 mg/m2 (range 114-861) and that of IFN alpha 2a was 264 MU (range 72-336). Four patients received IFN maintenance therapy, one for 3 months and three for 6 months. One patient had a complete response, four had a partial response, six had a stable disease and the disease progressed in one. One patient was non evaluable for response. All patients were assessable for toxicity. Hematological toxicity was the most frequently observed but was manageable (grade 3 anemia in five patients, grade 3 thrombocytopenia in three patients, grade 3 neutropenia in five patients). Grade 1 renal toxicity was observed in six patients, grade 2-3 asthenia in six patients and an average 5-kg weight loss was noted in nine patients. In conclusion, systemic combination of CDDP and IFN alpha 2a in large doses is effective at the expense of non-negligible toxicity.

Modulated expression of human leucocyte antigen class I and class II determinants in hyperplastic and malignant human prostatic epithelium

OBJECTIVES

To determine whether human prostatic carcinoma cells express Class I and/or Class II major histocompatibility complex (MHC) determinants and whether they might thus be immune-competent targets for cell-mediated cytotoxicity.

MATERIALS AND METHODS

Immunohistochemistry, performed both before and after neuraminidase digestion, was employed to compare 13 benign prostatic hyperplasias with 42 primary and 44 metastatic prostatic carcinomas obtained from the United Kingdom and from the United States of America. Expression of beta 2-microglobulin was used as the marker of Class I and HLA-DR as the marker of Class II expression.

RESULTS

Before desialylation, Class I MHC determinants were expressed in all of the benign hyperplasias, in 26% of primary carcinomas and in 14% of lymph node metastases. Cells expressing Class II determinants were identified in 69% of benign hyperplasias and in 2% of primary carcinomas, but in none of the lymph node metastases. After desialylation. Class I determinants were expressed in 100% of benign hyperplasias. 59% of primary carcinomas and 34% of the lymph node metastases. Class II determinants were expressed in 100% of benign hyperplasias, but only 19% of primary carcinomas and 5% of the lymph node metastases. While more than 50% of epithelial cells in each of the benign hyperplasias expressed MHCs, < 5% of the tumour cell populations in the positive malignant tissues (primary and metastatic) expressed MHCs, even after neuraminidase digestion. No correlation was found between expression of Class I or Class II MHC and Gleason morphological grade.

CONCLUSIONS

Failure to express Class I and/or Class II MHC determinants is a common feature of the majority of human prostatic carcinoma cells. Absence of these recognition molecules may be associated with avoidance of immune-surveillance and contribute to the metastatic dissemination of this malignancy.

Generation of an antitumour immune response to a murine mesothelioma cell line by the transfection of allogeneic MHC genes

We have determined whether transfection and expression of allogeneic MHC genes in a murine mesothelioma cell line can generate an anti-tumour immune response. The MHC genes encoding H-2Kb and H-2Dd were transfected into the mesothelioma cell line AC29 (derived from CBA mice, H-2k) and transfectant clones isolated. Each of five H-2Kb and 4 H-2Dd transfectant clones were unable to form tumours in CBA mice, although they had maintained their ability to form tumours in F1 crosses of CBA x C57b1/10 or CBA x BALB/c, respectively. Thus the tumours expressing the transfected MHC genes were rejected only in an allogeneic setting. Mice without tumours after transfectant challenge were inoculated on the opposite flank with 1 x 10(6) parental AC29. There was no evidence of systemic immunity to the parental cell line since tumours formed at the same rate as in naive mice. The mixing of allogeneic MHC transfectants with parental AC29 did, however, retard the growth of parental tumour. Our study illustrates that the expression of allogeneic MHC molecules on a highly immunosuppressive and non-immunogenic murine malignant mesothelioma cell line was able to stimulate rejection of tumour cells but was incapable of generating a systemic protective response against the parental cell line.

Effect of interferon-alpha 2a on malignant mesothelioma

Malignant mesothelioma (MM) is a tumor that is resistant to conventional therapy. Interferon-alpha (IFN-alpha) has been used in the treatment of some human tumors, and we have previously demonstrated an in vitro anti-proliferative effect of IFN against MM cell lines. Therefore, the effect of recombinant human IFN-alpha (IFN-alpha 2a) (Roferon-A, Hoffmann-La Roche) on previously untreated patients with MM has been studied. Twenty-five patients (24 male and 1 female), with a mean age of 59 +/- 9.9 years, were treated for 3 months with IFN-alpha 2a. The starting dose was 3 x 10(6) IU daily increasing to a maximum of 18 x 10(6) IU daily or as tolerated. All patients had measurable tumor on thoracic CT prior to commencement. CT scans were performed at 6 and 12 weeks to determine tumor response. Twenty patients completed 3 months of treatment. Five patients were withdrawn because of disease progression. Side effects were predictable and dose related. Dose reductions were necessary in 12 patients for grade 2 toxicity. One patient had a complete response (CR), 2 patients had partial responses (PR) (response rate = 12%), 13 (52%) patients remained stable, 1 of whom exhibited a delayed PR, and 9 (36%) had progressive disease. These data suggest that IFN-alpha 2a is well tolerated in patients with MM and is active against MM in a proportion of patients.

T cell receptor haplotypes in families of patients with insulin-dependent diabetes mellitus

The frequencies of Bgl 11 and BamH1 restriction fragment length polymorphisms (RFLP) of C beta, V beta 8, V beta 11 and V beta 7.2 have been defined in a healthy Australian population. Linkage disequilibrium between alleles of the T cell receptor (TCR) V beta 8 and V beta 11 gene segments has been confirmed. We have also confirmed the lack of linkage disequilibrium between either of these loci and alleles at C beta or V beta 7.2. Using RFLPs at V beta 11 and V beta 8 loci TCR beta haplotypes have been identified in five families in which the probands have insulin-dependent diabetes mellitus (IDDM). An extremely rare haplotype, marked by the higher molecular weight BamH1 allele (H, H) at each of V beta 11 and V beta 8, was found in the DR4+ DR3- probands of two families (P = 0.004). In three families in which the probands had DR3, the more common TCR haplotype LH (V beta 11, V beta 8) was found. Taken together, these data confirm that linkage disequilibrium does exist in the TCR beta locus, at least in some regions, and suggest that detailed analysis of the relationship between TCR V beta haplotypes and HLA is warranted since these RFLPs may be markers for important allelic V gene sequence variations.

An analysis of the relationship between gamma delta T cell receptor V gene usage and non-major histocompatibility complex-restricted cytotoxicity

gamma delta T cells are capable of mediating non-major histocompatibility complex (MHC) restricted lysis of a variety of tumour cell lines. The mechanism of this lysis and its significance in tumour immunity are not clear. We have used a panel of five malignant mesothelioma (MM) cell lines, as well as standard tumour targets K562 and Daudi, to investigate some of the factors which could be involved in non-MHC restricted cytotoxicity mediated by gamma delta T cells. Individual MM cell lines, representing a panel of lines derived from a single cell type, varied in their susceptibility to lysis by gamma delta T cell clones. Individual gamma delta T cell clones also showed unique cytotoxic profiles, and differed in their cytotoxic potential. T cell receptor (TCR) V gamma gene usage correlated with the ability of clones to lyse Daudi or K562; clones lysing Daudi expressing V gamma 9 and clones lysing K562 expressing V gamma I subgroup genes. No strict correlation between V gamma and V delta gene usage and MM reactivity was, however, demonstrable. There was also no correlation between gamma delta T cell lysis of MM cell lines and the capacity of gamma delta T cells to produce interferon-gamma, tumour necrosis factor-alpha, interleukin-2 or interleukin-4, nor with their expression of CD8.

Establishment of a murine model of malignant mesothelioma

Malignant mesothelioma (MM) is an aggressive tumour of the serosal cavities which is associated with previous asbestos exposure and is generally found to be resistant to conventional forms of therapy. Adequate scientific and clinical assessment of this disease has been severely limited by the relatively low incidence of mesothelioma and the lack of representative cell lines and animal models. The purpose of this study was to develop an asbestos-induced murine model of MM both as an in vivo-passaged malignancy and as in vitro-established cell lines. Such a model system would be invaluable for use in the study of various cellular, molecular and genetic aspects of the disease, and for the pre-clinical evaluation of potential therapeutic agents. BALB/c and CBA mice were injected intraperitoneally with crocidolite asbestos. Seven to 25 months after exposure, 35% of the mice developed mesothelioma (5 BALB/c, 9 CBA), as determined by standard cytological and histological parameters. From these primary tumours, 12 continuously growing cell lines (5 BALB/c, 7 CBA) were established in culture. All have been confirmed as mesothelioma by cytological and ultrastructural (electron microscopy) analyses. These lines have been in culture for 7 to 24 months and have achieved passages above 32 (range 32 to 106). As in the human disease, the murine mesothelioma lines vary in their morphology and growth rates (doubling times ranging from 14 to 30 hr). All cell lines produced tumours when injected into syngeneic mice.

Chemosensitivity and cytokine sensitivity of malignant mesothelioma

Malignant mesothelioma arises in serosal tissues, is locally invasive, and is usually resistant to chemotherapeutic agents used clinically. To determine whether resistance to cytotoxic drugs was an inherent characteristic of mesothelioma cells, we performed in vitro chemosensitivity testing on five fully characterised human malignant mesothelioma cell lines and, for comparison, on three lines representative of clinically drug-resistant solid-tissue carcinomas using the MTT (tetrazolium bromide) assay system. Mesothelioma cell lines were intrinsically resistant to eight common antineoplastic drugs, with concentrations that produced a 50% reduction in optical density (IC50 values) for all drugs being equivalent, if not higher, for mesothelioma cell lines as compared with lung and colon carcinoma cell lines. We then investigated the direct anti-mesothelioma activity of recombinant human cytokines with their antineoplastic properties. All five mesothelioma cell lines were resistant to tumour necrosis factor, but they displayed varying degrees of sensitivity to interferons (IFNs). IFN gamma directly inhibited the growth of two of five mesothelioma lines. IFN alpha displayed little activity against four of five mesothelioma lines. The mesothelioma cells that were sensitive to IFN alpha were resistant to IFN gamma, indicating that sensitivity to IFNs is not a genetic characteristic of malignant mesothelioma cells. Significant interactions between cytokines in combination were not observed.