SV40 Tag-specific cytotoxic T lymphocytes generated from the peripheral blood of malignant pleural mesothelioma patients

Malignant pleural mesothelioma (MPM) is an aggressive cancer, with survival of less than one year following diagnosis and treatment with current protocols. Recent studies have demonstrated the presence of the simian virus 40 (SV40)-like, large tumor antigen (Tag) in nearly 60% of MPMs. SV40 Tag is a viral-encoded tumor-specific antigen, and thus a potential target for the induction of anti-tumor immunity and the development of therapeutic vaccines. We describe here evidence for the existence of SV40 Tag-specific immune responses in patients with MPM whose tumors express Tag. Humoral immunity was demonstrated by the detection of IgG titers against Tag in serum samples from 1/3 of patients examined. CTLs were generated from the peripheral blood of an HLA-A2(+) MPM patient with a synthetic peptide representing an HLA-A2 binding epitope in SV40 Tag. The CTLs demonstrated epitope fine specificity, in that other peptides from SV40 Tag and a peptide from influenza virus were not recognized in the context of HLA-A2. Moreover, the CTLs were capable of recognizing mesothelioma tumor cells that expressed SV40 Tag, in an MHC class I restricted manner.     

Carbonic anhydrase IX in malignant pleural mesotheliomas: A potential target for anti-cancer therapy

Malignant mesothelioma is a neoplasm deriving from mesothelial cells, which line the body cavities. The most common type is malignant pleural mesothelioma (MPM), which is a locally aggressive malignancy with poor prognosis. To improve both the clinical diagnostics and treatment it is necessary to identify novel molecular targets which are characteristic for MPM. Although carbonic anhydrase (CA) enzymes have been linked to pH regulation and spread of cancer cells, they have not been thoroughly studied in MPM specimens. We investigated by immunohistochemistry the expression of CA isozymes II, VII, IX, and XII in a series of 27 histological MPM tumor samples. CA IX was absent in the normal lung alveolar cells, whereas it was abundantly expressed in the normal pleural mesothelium and malignant mesothelioma cells. CA VII also showed weak or moderate reactions in several cases of mesotheliomas. Neither high expression of CA VII nor CA IX did correlate significantly with the survival of the patients. The very high expression of CA IX in MPM suggests that it could represent a novel molecular target for cancer research applications.     

Label-Free Detection of Breast Masses Using Multiphoton Microscopy

Histopathology forms the gold standard for the diagnosis of breast cancer. Multiphoton microscopy (MPM) has been proposed to be a potentially powerful adjunct to current histopathological techniques. A label-free imaging based on two- photon excited fluorescence and second-harmonic generation is developed for differentiating normal breast tissues, benign, as well as breast cancer tissues. Human breast biopsies (including human normal breast tissues, benign as well as breast cancer tissues ) that are first imaged (fresh, unfixed, and unstained) with MPM and are then processed for routine H-E histopathology. Our results suggest that the MPM images, obtained from these unprocessed biopsies, can readily distinguish between benign lesions and breast cancers. In the tissues of breast cancers, MPM showed that the tumor cells displayed marked cellular and nuclear pleomorphism. The tumor cells, characterized by irregular size and shape, enlarged nuclei, and increased nuclear-cytoplasmic ratio, infiltrated into disrupted connective tissue, leading to the loss of second-harmonic generation signals. For breast cancer, MPM diagnosis was 100% correct because the tissues of breast cancers did not have second-harmonic generation signals in MPM imaging. On the contrary, in benign breast masses, second-harmonic generation signals could be seen easily in MPM imaging. These observations indicate that MPM could be an important potential tool to provide label-free noninvasive diagnostic impressions that can guide surgeon in biopsy and patient management.     

Frequent increased gene copy number and high protein expression of tRNA (cytosine-5-)-methyltransferase (NSUN2) in human cancers

NSUN2, also known as SAKI or MISU, is a methyltransferase which catalyses (cytosine-5-)-methylation of tRNA. The human NSUN2 gene is located on chromosome 5p15.31-33. We show that NSUN2 gene copy number is increased in oral and colorectal cancers. Protein expression levels of NSUN2 were determined by immunoblot using novel polyclonal antibodies raised against a synthetic peptide corresponding to the C-terminal region of the protein. In most normal tissues, NSUN2 expression levels were extremely low. On the other hand, oral and colorectal cancers typically expressed high levels of NSUN2. The level of NSUN2 was similar in interphase and mitotic cells, and immunohistochemical analysis demonstrated strong staining for NSUN2 in oral and colon cancer tissues when compared with normal tissues, providing a distinct diagnostic significance for NSUN2 in comparison with Ki-67, a widely used marker of actively proliferating cells. In addition, elevated protein expression of NSUN2 was confirmed by immunohistochemical analysis of various cancers including esophageal, stomach, liver, pancreas, uterine cervix, prostate, kidney, bladder, thyroid, and breast cancers. NSUN2 is regulated by Aurora-B, a newly developed molecular target for cancer therapy, leading us to propose that NSUN2 might become a valuable target for cancer therapy and a cancer diagnostic marker.     

Inhibition of yes‐associated protein down‐regulates PD‐L1 (CD274) expression in human malignant pleural mesothelioma

Although tumour PD‐L1 (CD274) expression had been used as a predictive biomarker in checkpoint immunotherapy targeting the PD1/PD‐L1 axis in various cancers, the regulation of PD‐L1 (CD274) expression is unclear. Yes‐associated protein (YAP), an important oncogenic protein in Hippo signalling pathway, reportedly promotes cancer development. We investigated whether inhibition of YAP down‐regulates PD‐L1 (CD274) in human malignant pleural mesothelioma (MPM). Western blotting showed that 2 human MPM cell lines (H2052 and 211H) had increased PD‐L1 protein expression compared to H290, MS‐1 and H28 cells. In H2052 and 211H cells, PD‐L1 mRNA expression was significantly increased compared to other MPM cell lines; YAP knockdown by small interfering RNA decreased PD‐L1 protein and mRNA expression. Forced overexpression of the YAP gene increased PD‐L1 protein expression in H2452 cells. Chromatin immunoprecipitation (ChIP) assay showed the precipitation of PD‐L1 enhancer region encompassing 2 putative YAP‐TEAD‐binding sites in H2052 cells. We found that, in human MPM tissue microarray samples, YAP and PD‐L1 concurrently expressed in immunohistochemistry stain (n = 70, P < .05, chi‐square). We conclude that PD‐L1 is correlated with YAP expression, and inhibition of YAP down‐regulates PD‐L1 expression in human MPM. Further study of how YAP regulates PD‐L1 in MPM is warranted.     

Localization of tartrate-resistant acid phosphatase in human placenta

Summary Tartrate-resistant acid phosphatase is an inducible marker of cell differentiation and activation expressed by specialized cells of macrophage lineage and some activated lymphocytes. Clinically, this phosphatase is a diagnostic marker for hairy cell leukaemia and osteoclast activity. The cDNA for this enzyme has been cloned from a placental expression library, yet the cell(s) expressing the enzyme protein has not been determined with certainty. Our laboratories have developed a monoclonal antibody, 9C5, suitable for immunohistochemical localization of tartrate-resistant acid phosphatase in paraffin sections. The purpose of this study was to use antibody 9C5 to identify cells expressing tartrate-resistant acid phosphatase in sections of paraffin-embedded, normal, full-term placenta and to determine if those cells expressed other macrophage markers including CD68(PG-M1 antibody), LN5, lysozyme ₁-antitrypsin and ₁-antichymotrypsin. Histochemical localization of activity in frozen sections was compared with immunohistochemical localization in paraffin sections of the same tissue specimens. The activity and antigenicity of this enzyme were detected in decidual cells, syncytiotrophoblast, and some macrophages distributed throughout maternal and embryonic tissues, but not in neutrophils. Unlike other tissues previously examined, placenta contains significant numbers of the phosphate-positive cells that are not of macrophage origin.     

Curcumin suppresses growth of mesothelioma cells in vitro and in vivo, in part, by stimulating apoptosis

Malignant pleural mesothelioma (MPM) is an aggressive, asbestos-related malignancy of the thoracic pleura. Although, platinum-based agents are the first line of therapy, there is an urgent need for second-line therapies to treat the drug-resistant MPM. Cell cycle as well as apoptosis pathways are frequently altered in MPM and thus remain attractive targets for intervention strategies. Curcumin, the major component in the spice turmeric, alone or in combination with other chemotherapeutics has been under investigation for a number of cancers. In this study, we investigated the biological and molecular responses of MPM cells to curcumin treatments and the mechanisms involved. Flow-cytometric analyses coupled with western immunoblotting and gene-array analyses were conducted to determine mechanisms of curcumin-dependent growth suppression of human (H2373, H2452, H2461, and H226) and murine (AB12) MPM cells. Curcumin inhibited MPM cell growth in a dose- and time-dependent manner while pretreatment of MPM cells with curcumin enhanced cisplatin efficacy. Curcumin activated the stress-activated p38 kinase, caspases 9 and 3, caused elevated levels of proapoptotic proteins Bax, stimulated PARP cleavage, and apoptosis. In addition, curcumin treatments stimulated expression of novel transducers of cell growth suppression such as CARP-1, XAF1, and SULF1 proteins. Oral administration of curcumin inhibited growth of murine MPM cell-derived tumors in vivo in part by stimulating apoptosis. Thus, curcumin targets cell cycle and promotes apoptosis to suppress MPM growth in vitro and in vivo. Our studies provide a proof-of-principle rationale for further in-depth analysis of MPM growth suppression mechanisms and their future exploitation in effective management of resistant MPM.     

gp78 is specifically expressed in human prostate cancer rather than normal prostate tissue

Elevated expression of gp78 has been observed in many types of cancers including lung, stomach, colon, liver and skin cancer. But there is no report about its expression in prostate cancers. In this study, using immunohistochemical staining we found gp78 is highly expressed in prostate cancers especially early stage tumors, but not in normal prostate tissues. gp78 protein expression is heterogeneous. In some tumors it was expressed in basal cells, while others in stromal cells. For gp78 is a ubiquitin E3 ligase, we then investigated the expression pattern of its cognate E2 (ubiquitin conjugating enzyme)-Ube2g2 in prostate cancers. We found it was expressed in both cancerous and normal tissues of prostate without significant differences in expression level. And unlike gp78, it exhibited a homogeneous expression pattern in different cell types in prostate tissues. In conclusion, our results indicate that gp78 is expressed specifically in human prostate cancer rather than normal prostate tissues, it could be a putative biomarker for prostate cancer diagnosis.     

The roles of different pathways in the release of cholesterol from macrophages

Cholesterol efflux occurs by different pathways, including transport mediated by specific proteins. We determined the effect of enriching cells with free cholesterol (FC) on the release of FC to human serum. Loading Fu5AH cells with FC had no effect on fractional efflux, whereas enriching mouse peritoneal macrophages (MPMs) resulted in a doubling of fractional efflux. Efflux from cholesterol-normal MPM and Fu5AH cells to 15 human sera correlated well with HDL parameters. However, these relationships were reduced or lost with cholesterol-loaded MPMs. Using macrophages from scavenger receptor class B type I (SR-BI)-, ABCA1-, and ABCG1-knockout mice, together with inhibitors of SR-BI- and ABCA1-mediated efflux, we were able to quantitate efflux upon loading macrophages with excess cholesterol and to establish the contributions of the various efflux pathways in cholesterol-normal and -enriched cells. The removal of ABCA1 had essentially no effect on the total efflux when cell cholesterol levels were normal. However, in cholesterol-enriched cells, the removal of ABCA1 reduced efflux by 50%. Approximately 20% of the efflux stimulated by FC-loading MPM is attributable to ABCG1. The SR-BI contribution to efflux was small. Another pathway that is present in all cells is aqueous diffusion. Our studies demonstrate that this mechanism is one of the major contributors to efflux, particularly in cholesterol-normal cells.     

CD8+ tumor-infiltrating lymphocytes predict favorable prognosis in malignant pleural mesothelioma after resection

Defects in human leukocyte antigen (HLA) class I expression may allow tumor cells to escape immune recognition. T cell infiltration is associated with a good prognosis in many cancers. However, the role of HLA class I expression and tumor-infiltrating lymphocytes (TILs) in malignant pleural mesothelioma (MPM) has not been fully analyzed. In the present study, we investigated the immune profiles and conducted outcome analyses of MPM patients. HLA class I expression and TILs (CD4⁺, CD8⁺, and NK cells) were detected by immunohistochemistry in a series of 44 MPM cases. To detect HLA class I expression, specimens were stained with the anti-pan HLA class I monoclonal antibody EMR8-5. The expression of HLA class I was positive in all patients. There was no case that showed negative HLA class I expression. The density of CD4⁺ and CD8⁺ TILs were strongly correlated (R = 0.76, p < 0.001). A high density of CD8⁺ TILs was a significantly better prognostic factor for the survival of patients with extrapleural pneumonectomy (p < 0.05). Multivariate analysis revealed that a high density of CD8⁺ TILs is an independent prognostic factor for patients who underwent extrapleural pneumonectomy. The presence of intratumoral CD8⁺ T cells was correlated with an improved clinical outcome, raising the possibility that CD8⁺ T cells might play a pivotal role in the antitumor immune response against MPMs. Thus, the stimulation of CD8⁺ lymphocytes might be an efficacious immunotherapy for MPM patients.     

血栓调节蛋白在胚胎肺及肺癌中的表达

目的研究血栓调节蛋白(thrombomodulin,TM)在胚胎肺、正常肺组织及肺癌组织中的表达。方法以不同周龄的胚胎肺组织、正常成人肺组织、肺癌组织为研究对象,应用免疫组织化学SP法检测TM的存在。结果8、15、18、21、24、27、29周人胎肺组织中,TM在气管纤毛柱状上皮细胞、I型和Ⅱ型肺泡上皮细胞及软骨、结缔组织均呈阴性表达,围绕肺泡上皮细胞团周围的血管内皮细胞阳性表达。正常成人支气管纤毛柱状上皮细胞、肺泡上皮细胞不表达,但在血管内皮细胞呈阳性表达。TM在鳞状上皮不典型增生的细胞膜和细胞问桥表达,在肺鳞癌表达,阳性率为97．3％(34／35),在癌细胞膜和细胞问桥阳性表达,但腺癌、小细胞癌癌细胞不表达。结论TM在胚胎肺以及成人肺仅见于血管内皮细胞,在支气管上皮、肺泡上皮不表达。与其它的血管内皮细胞标记物不同,TM的表达在肺鳞癌与腺癌表扶明显不同．右助于鉴别肺鳞癌与肺腺癌．     

Cell protection, resistance and invasiveness of two malignant mesotheliomas as assessed by 10K-microarray

Malignant pleural mesothelioma (MPM) is an aggressive serosal tumor, strongly associated with former exposure to asbestos fibers and for which there is currently no effective treatment available. In human, MPM is characterized by a high local invasiveness, poor prognosis and therapeutic outcomes. In order to assess molecular changes that specify this phenotype, we performed a global gene expression profiling of human MPM. Using a 10,000-element microarray, we analyzed mRNA relative gene expression levels by comparing a mesothelioma cell line to either a pleural cell line or tumor specimens. To analyze these gene expression data, we used various bioinformatics softwares. Hierarchical clustering methods were used to group genes and samples with similar expression in an unsupervised mode. Genes of known function were further sorted by enzyme, function and pathway clusters using a supervised software (IncyteGenomics). Taken together, these data defined a molecular fingerprint of human MPM with more than 700 up- or down-regulated genes related to several traits of the malignant phenotype, specially associated with MPM invasiveness, protection and resistance to anticancer defenses. This portrait is meaningful in disease classification and management, and relevant in finding new specific markers of MPM. These molecular markers should improve the accuracy of mesothelioma diagnosis, prognosis and therapy.     

Proteasome Inhibitor MG132 Induces Apoptosis and Inhibits Invasion of Human Malignant Pleural Mesothelioma Cells

Malignant pleural mesothelioma (MPM) is an aggressive malignancy tightly associated with asbestos exposure. The increasing incidence of MPM and its resistance to all therapeutic modalities necessitate an urgent development of new treatments for MPM. Proteasome inhibitors (PIs) have emerged as promising agents for treating human cancers that are refractory to current chemotherapies. In this study, we characterized MG132, a commonly used PI, for its proapoptotic and anti-invasion activities in NCI-H2452 and NCI-H2052 human thoracic MPM cell lines to determine the therapeutic effect of PIs on MPM. We found that as low as 0.5 microM MG132 caused a significant apoptosis in both cell lines as evidenced by DNA damage, cleavage of poly ADP-ribose polymerase and caspases 3, 7, and 9, and mitochondrial release of Smac/DIABLO and Cytochrome c. Mitochondrial caspase activation was found to be the underlying mechanism of the MG132-induced apoptosis. Mcl-1, among the Bcl-2 and IAP (inhibitor of apoptosis protein) antiapoptotic family proteins tested, was proved to be a major inhibitor of the MG132-induced apoptosis in MPM cells. Meanwhile, subapoptotic doses of MG132 inhibited the invasion of both MPM cell lines through reducing Rac1 activity. These observations demonstrate that MG132 possesses proapoptotic and anti-invasion activities in human MPM cells, therefore encouraging further investigations on the value of PIs for treating MPM.     

Expression of the Stem Cell Factor Nestin in Malignant Pleural Mesothelioma Is Associated with Poor Prognosis

Background

The epithelioid and sarcomatoid histologic variants of malignant pleural mesothelioma (MPM) can be considered as E- and M-parts of the epithelial-mesenchymal transition (EMT) axis; the biphasic being an intermediate. EMT is associated with an increase of stem cell (SC) traits. We correlated the neural crest SC marker nestin and the EMT marker periostin with histology, type of neo-adjuvant chemotherapy (CT) and overall survival (OS) of MPM patients.

Patients and Methods

Tumor tissues of a historic cohort 1 (320 patients) and an intended induction chemotherapy followed by extrapleural pneumonectomy (EPP) cohort 2 (145 patients) were immunohistochemically H-scored (intensity of immunoreactivity multiplied by frequency of stained cells). Paired chemo-naïve biopsies and -treated surgical specimens were available for 105/145 patients. CT included platinum/gemcitabine (Pla/Gem) or platinum/pemetrexed (Pla/Pem).

Results

Expression of any cytosolic nestin progressively increased from epithelioid to biphasic to sarcomatoid MPM in cohort 1, whereas the diagnostic markers calretinin and podoplanin decreased. In cohort 2, Pla/Pem CT increased the expression level of nestin in comparison to Pla/Gem, whereas the opposite was found for periostin. In Pla/Pem treated patients, nestin was higher in biphasic MPM compared to epithelioid. In addition to non-epithelioid histology, any expression of nestin in chemo-naïve biopsies (median overall survival: 22 vs. 17 months) and chemo-treated surgical specimens (18 vs. 12 months) as well as high periostin in biopsies (23 vs. 15 months) were associated with poor prognosis. In the multivariate survival analysis, any nestin expression in chemo-naïve biopsies proved to be an independent prognosticator against histology. In both pre- and post-CT situations, the combination of nestin or periostin expression with non-epithelioid histology was particularly/ dismal (all p-values <0.05).

Conclusions

The SC marker nestin and the EMT marker periostin allow for further prognostic stratification among histologic variants of MPM. Their expression level is influenced by neo-adjuvant chemotherapy.     

Proteomic differential display analysis identified upregulated astrocytic phosphoprotein PEA‐15 in human malignant pleural mesothelioma cell lines

We performed proteomic differential display analysis of human malignant pleural mesothelioma (MPM) cell lines and a human pleural mesothelial cell line by using 2‐DE and LC‐MS/MS. The human MPM cell lines were NCI‐H28, NCI‐H2052 and NCI‐H2452, and the human pleural mesothelial cell line was MeT‐5A. Between MeT‐5A and NCI‐H2052, we found 38 protein spots whose expression levels were different, from the results of 2‐DE; 28 protein spots appeared higher, and 10 other protein spots lower in NCI‐H2052 than in MeT‐5A. These spots were analyzed by LC‐MS/MS analysis and identified by a peptide sequence tag. However, from the results of 2‐DE of the other cell lines, there was only one consistently upregulated protein, astrocytic phosphoprotein PEA‐15, in all three MPM cell lines. Western blotting using specific antibodies against PEA‐15 confirmed the elevated expression level of PEA‐15 in all three MPM cell lines compared with MeT‐5A cells and normal pleura tissues from patients. PEA‐15 was knocked down in NCI‐H2052 cells, and the proliferation of PEA‐15‐silenced NCI‐H2052 cells was suppressed 7–15% compared with negative control cells. These results suggest that PEA‐15 expression is likely to be associated with the tumorigenesis of MPM.     

Distinct Expression Levels and Patterns of Stem Cell Marker,Aldehyde Dehydrogenase Isoform 1 (ALDH1), in Human Epithelial Cancers

Aldehyde dehydrogenase isoform 1 (ALDH1) has been proved useful for the identification of cancer stem cells. However, our knowledge of the expression and activity of ALDH1 in common epithelial cancers and their corresponding normal tissues is still largely absent. Therefore, we characterized ALDH1 expression in 24 types of normal tissues and a large collection of epithelial tumor specimens (six cancer types, n = 792) by immunohistochemical staining. Using the ALDEFUOR assay, ALDH1 activity was also examined in 16 primary tumor specimens and 43 established epithelial cancer cell lines. In addition, an ovarian cancer transgenic mouse model and 7 murine ovarian cancer cell lines were analyzed. We found that the expression levels and patterns of ALDH1 in epithelial cancers are remarkably distinct, and they correlate with their corresponding normal tissues. ALDH1 protein expression levels are positively correlated with ALDH1 enzymatic activity measured by ALDEFLUOR assay. Long-term in vitro culture doesn''t significantly affect ALDH1 activity in epithelial tumor cells. Consistent with research on other cancers, we found that high ALDH1 expression is significantly associated with poor clinical outcomes in serous ovarian cancer patients (n = 439, p = 0.0036). Finally, ALDH^br tumor cells exhibit cancer stem cell properties and are resistant to chemotherapy. As a novel cancer stem cell marker, ALDH1 can be used for tumors whose corresponding normal tissues express ALDH1 in relatively restricted or limited levels such as breast, lung, ovarian or colon cancer.     

Expression of the human copper influx transporter 1 in normal and malignant human tissues.

The major copper influx transporter, copper transporter 1 (hCTR1), controls the cellular accumulation of cisplatin in mammalian cells. The goal of this study was to determine the pattern of hCTR1 expression in normal and malignant human tissues. Tissue arrays were stained with an antibody specific for hCTR1 using standard immunohistochemical techniques. Particularly strong staining was noted in the alpha cells of the pancreatic islets, enteroendocrine cells of the gastric mucosa and bronchioles, C cells of the thyroid, and a subset of cells in the anterior pituitary. Frequency and intensity of hCTR1 staining in malignant tissues reflected the levels found in their normal tissue counterparts. For example, neither normal prostate nor prostate cancers expressed hCTR1, whereas it was commonly expressed in both normal colonic epithelium and in colon carcinomas. Strong staining was observed in a limited number of cases of carcinoid tumors, Ewing's sarcoma, and undifferentiated carcinomas. Although all tissues require copper, expression of hCTR1 was highly variable among normal tissues and among the major human malignancies, with the highest levels found in enteroendocrine cells. No hCTR1 expression was found in several common types of cancer, suggesting that hCTR1 expression is not commonly enhanced by transformation.