Faculty Bibliography

PURPOSE Mesothelin is currently considered the best available serum biomarker of malignant pleural mesothelioma. To examine the diagnostic accuracy and use of serum mesothelin in early diagnosis, we performed an individual patient data (IPD) meta-analysis. METHODS The literature search identified 16 diagnostic studies of serum mesothelin, measured with the Mesomark enzyme-linked immunosorbent assay. IPD of 4,491 individuals were collected, including several control groups and 1,026 patients with malignant pleural mesothelioma. Mesothelin levels were standardized for between-study differences and age, after which the diagnostic accuracy and the factors affecting it were examined with receiver operating characteristic (ROC) regression analysis. Results At a common diagnostic threshold of 2.00 nmol/L, the sensitivities and specificities of mesothelin in the different studies ranged widely from 19% to 68% and 88% to 100%, respectively. This heterogeneity can be explained by differences in study population, because type of control group, mesothelioma stage, and histologic subtype significantly affected the diagnostic accuracy. The use of mesothelin in early diagnosis was evaluated by differentiating 217 patients with stage I or II epithelioid and biphasic mesothelioma from 1,612 symptomatic or high-risk controls. The resulting area under the ROC curve was 0.77 (95% CI, 0.73 to 0.81). At 95% specificity, mesothelin displayed a sensitivity of 32% (95% CI, 26% to 40%). CONCLUSION In patients suspected of having mesothelioma, a positive blood test for mesothelin at a high-specificity threshold is a strong incentive to urge further diagnostic steps. However, the poor sensitivity of mesothelin clearly limits its added value to early diagnosis and emphasizes the need for further biomarker research.

The DNA replication protein Ciz1 promotes initiation of mammalian DNA replication in cooperation with cyclin A-dependent kinase, most likely by delivering cyclin A to sites where cyclin E-dependent pre-replication complex assembly has taken place. Normally, Ciz1 is anchored within nuclear matrix-associated foci that co-localize with sites of DNA replication, but in the absence of anchor domain Ciz1 retains the ability to promote initiation of DNA replication in isolated nuclei so attachment to the nuclear matrix is not essential for function. Expression of DNA replication and nuclear matrix anchor domains of Ciz1 are uncoupled and uneven at the transcript level in a wide range of common solid tumours, including breast and lung. In cell-based assays, recombinant anchor domain protein interferes with attachment of endogenous Ciz1 to the nuclear matrix, revealing a dominant negative effect that also impacts on nuclear matrix-recruitment of key components of the pre-replication complex. This suggests that Ciz1 normally plays a role in localizing initiation of DNA replication to the nuclear matrix. These findings implicate spatially unconstrained DNA replication as a source of nuclear disorder in cancer cells. We identified a variant Ciz1 isoform with alterations in the nuclear matrix attachment domain and tumour-restricted expression. RNAi-mediated selective inhibition of variant Ciz1 expression is sufficient to restrain the growth of tumour cells that express it, identifying variant Ciz1 as a functionally relevant driver of cell proliferation. We also present evidence that this form of Ciz1 is expressed in 34/35 lung tumours but not adjacent tissue, giving rise to stable protein quantifiable in less than a microlitre of patient plasma by western blot. Using two independent sets, with 170 and 160 samples, variant Ciz1 correctly identified stage 1 lung cancer patients with clinically useful accuracy. For set 1, mean variant Ciz1 level (+SD) in individuals without diagnosed tumours established a thre!

The medicinal plant Withania somnifera has been used for over centuries in Indian Ayurvedic medicine to treat a wide spectrum of disorders. Withaferin A (WA), a bioactive compound that is isolated from this plant, has recently been found to have anti-inflammatory, immuno-modulatory, anti-angiogenic, and anti-cancer properties. Here we investigated malignant pleural mesothelioma (MPM) suppressive effects of WA and the molecular mechanisms involved. WA inhibited growth of the murine as well as patient-derived MPM cells in part by decreasing the chymotryptic activity of the proteasome that resulted in accumulation of ubiquitinated proteins. WA suppression of MPM growth also involved elevated apoptosis as evidenced by activation of caspase-3, elevated levels of pro-apoptotic Bax protein and cleavage of poly-(ADP-ribose)-polymerase. Our studies including gene-array based analyses further revealed that WA suppressed a number of cell growth and metastasis-promoting genes including c-myc. WA treatments also promoted cleavage of vimentin as well as stimulated expression of CARP-1/CCAR1, a novel transducer of cell growth signaling. Knock-down of CARP-1, on the other hand, interfered with vimentin cleavage and MPM growth inhibitory effects of WA. Administration of 5mg/kg WA by daily i.p injections inhibited growth of murine MPM cell-derived tumors in vivo in part by inhibiting proteasome activity and stimulating apoptosis. Together our in vitro and in vivo studies suggest that WA suppresses MPM growth by targeting multiple pathways that include blockage of proteasome activity and stimulation of apoptosis, and thus holds promise as an anti-MPM agent

Human malignant mesothelioma (MM) is an aggressive and highly lethal cancer, often associated with exposure to asbestos and erionite. Prognosis is poor, due to late-stage diagnosis and resistance to current conventional therapies. We previously showed that high-mobility group box-1 protein (HMGB1), a damage-associated molecular pattern (DAMP) protein, is involved in the early stages of mesothelial cell transformation. Here we show that HMGB1 establishes an autocrine circuit in MM cells influencing tumor cell proliferation and survival. MM cells express HMGB1 at high levels and secrete HMGB1 into the extracellular space. Accordingly, HMGB1 levels in MM patients' sera are significantly higher than in those of healthy individuals. In addition, motility, survival and anchorage-independent growth of HMGB1-secreting MM cells were inhibited in vitro by a monoclonal antibody (mAb) against HMGB1, by the recombinant HMGB1 competitive antagonist BoxA and by antibodies against the receptor for advanced glycation end products (RAGE). Inhibition of HMGB1 reduced the growth of MM xenografts in SCID mice and extended survival. Our findings indicate that MM cells become "addicted" to HMGB1 and that targeting HMGB1 can be a promising novel therapeutic approach for MM

INTRODUCTION: Osteopontin (OPN) is a ubiquitous protein associated with a wide range of normal and pathologic functions. It is a central regulator of malignant phenotype in non-small cell lung cancer (NSCLC). OPNa, the full length isoform, is disproportionately expressed in NSCLC tumors and cell lines, and increases malignant behavior when over expressed. OPNc, the shortest isoform, does not induce malignant properties when expressed in NSCLC. The only structural difference between OPNa and OPNc is the transcription of exon 4. The hypothesis of this project is that a small interfering peptide to OPN exon 4 will reduce in vitro malignant activity in NSCLC. METHODS: A 16-amino acid peptide which mimics the central sequence in OPN exon 4 and a scrambled sham were constructed and florescent labeled. Three NSCLC cell lines, H358 (low), A549 (moderate), and H460 (high endogenous OPN) were used in binding, proliferation, and invasion assays in presence of exon 4 mimic or sham. Cisplatin sensitivity was performed with peptides in A549. RESULTS: There was florescent evidence for cell surface binding of the exon 4 mimic in all of the NSCLC cell lines without binding of the sham. The exon 4 mimic significantly decreased in vitro invasion and proliferation in the A549 and H460 cell lines, with a lesser effect in H358 with low endogenous OPN. (Table) The exon 4 mimic increased cisplatin sensitivity, decreasing cell viability 2-fold compared to sham and control at cisplatin concentrations 0.1-0.8 uM/ml. CONCLUSIONS: Exon 4 of OPN has not previously been identified as a regulatory region essential for OPN's effect on malignant behavior. We have evidence for an un-described cell surface receptor to this region. A small mimicking peptide to OPN exon 4 significantly decreased in vitro malignant behavior, suggesting interference with important regulatory pathways. This novel binding site could serve as an ideal for target for antibody or small molecule therapies in NSCLC

Malignant mesothelioma (MM) is a neoplasm arising from mesothelial cells lining the pleural, peritoneal, and pericardial cavities. Over 20 million people in the US are at risk of developing MM due to asbestos exposure. MM mortality rates are estimated to increase by 5-10% per year in most industrialized countries until about 2020. The incidence of MM in men has continued to rise during the past 50 years, while the incidence in women appears largely unchanged. It is estimated that about 50-80% of pleural MM in men and 20-30% in women developed in individuals whose history indicates asbestos exposure(s) above that expected from most background settings. While rare for women, about 30% of peritoneal mesothelioma in men has been associated with exposure to asbestos. Erionite is a potent carcinogenic mineral fiber capable of causing both pleural and peritoneal MM. Since erionite is considerably less widespread than asbestos, the number of MM cases associated with erionite exposure is smaller. Asbestos induces DNA alterations mostly by inducing mesothelial cells and reactive macrophages to secrete mutagenic oxygen and nitrogen species. In addition, asbestos carcinogenesis is linked to the chronic inflammatory process caused by the deposition of a sufficient number of asbestos fibers and the consequent release of pro-inflammatory molecules, especially HMGB-1, the master switch that starts the inflammatory process, and TNF-alpha by macrophages and mesothelial cells. Genetic predisposition, radiation exposure and viral infection are co-factors that can alone or together with asbestos and erionite cause MM. J. Cell. Physiol. (c) 2011 Wiley-Liss, Inc

BACKGROUND: Low-dose computed tomography (CT) for lung cancer screening can reduce lung cancer mortality. The National Lung Screening Trial reported a 20% reduction in lung cancer mortality in high-risk smokers. However, CT scanning is extremely sensitive and detects non-calcified nodules (NCNs) in 24-50% of subjects, suggesting an unacceptably high false-positive rate. We hypothesized that by reviewing demographic, clinical and nodule characteristics, we could identify risk factors associated with the presence of nodules on screening CT, and with the probability that a NCN was malignant. METHODS: We performed a longitudinal lung cancer biomarker discovery trial (NYU LCBC) that included low-dose CT-screening of high-risk individuals over 50 years of age, with more than 20 pack-year smoking histories, living in an urban setting, and with a potential for asbestos exposure. We used case-control studies to identify risk factors associated with the presence of nodules (n = 625) versus no nodules (n = 557), and lung cancer patients (n = 30) versus benign nodules (n = 128). RESULTS: The NYU LCBC followed 1182 study subjects prospectively over a 10-year period. We found 52% to have NCNs >4 mm on their baseline screen. Most of the nodules were stable, and 9.7% of solid and 26.2% of sub-solid nodules resolved. We diagnosed 30 lung cancers, 26 stage I. Three patients had synchronous primary lung cancers or multifocal disease. Thus, there were 33 lung cancers: 10 incident, and 23 prevalent. A sub-group of the prevalent group were stable for a prolonged period prior to diagnosis. These were all stage I at diagnosis and 12/13 were adenocarcinomas. CONCLUSIONS: NCNs are common among CT-screened high-risk subjects and can often be managed conservatively. Risk factors for malignancy included increasing age, size and number of nodules, reduced FEV1 and FVC, and increased pack-years smoking. A sub-group of screen-detected cancers are slow-growing and may contribute to over-diagnosis and lead-time biases.