NGR-TNF Engineering with an N-Terminal Serine Reduces Degradation and Post-Translational Modifications and Improves Its Tumor-Targeting Activity.

The therapeutic index of cytokines in cancer therapy can be increased by targeting strategies based on protein engineering with peptides containing the CNGRC (NGR) motif, a ligand that recognizes CD13-positive tumor vessels. We show here that the targeting domain of recombinant CNGRC-cytokine fusion proteins, such as NGR-TNF (a CNGRC-tumor necrosis factor-α (TNF) conjugate used in clinical studies) and NGR-EMAP-II, undergoes various post-translational modification and degradation reactions that lead to the formation of markedly heterogeneous products. These modifications include N-terminal cysteine acetylation or the formation of various asparagine degradation products, the latter owing to intramolecular interactions of the cysteine α-amino group with asparagine and/or its succinimide derivative. Blocking the cysteine α-amino group with a serine (SCNGRC) reduced both post-translational and degradation reactions. Furthermore, the serine residue reduced the asparagine deamidation rate to isoaspartate (another degradation product) and improved the affinity of NGR for CD13. Accordingly, genetic engineering of NGR-TNF with the N-terminal serine produced a more stable and homogeneous drug (called S-NGR-TNF) with improved antitumor activity in tumor-bearing mice, either when used alone or in combination with chemotherapy. In conclusion, the targeting domain of NGR-cytokine conjugates can undergo various untoward modification and degradation reactions, which can be markedly reduced by fusing a serine to the N-terminus. The SCNGRC peptide may represent a ligand for cytokine delivery to tumors more robust than conventional CNGRC. The S-NGR-TNF conjugate (more stable, homogeneous, and active than NGR-TNF) could be rapidly developed for clinical trials.

Boosting Interleukin-12 Antitumor Activity and Synergism with Immunotherapy by Targeted Delivery with isoDGR-Tagged Nanogold.

The clinical use of interleukin-12 (IL12), a cytokine endowed with potent immunotherapeutic anticancer activity, is limited by systemic toxicity. The hypothesis is addressed that gold nanoparticles tagged with a tumor-homing peptide containing isoDGR, an αvß3-integrin binding motif, can be exploited for delivering IL12 to tumors and improving its therapeutic index. To this aim, gold nanospheres are functionalized with the head-to-tail cyclized-peptide CGisoDGRG (Iso1) and murine IL12. The resulting nanodrug (Iso1/Au/IL12) is monodispersed, stable, and bifunctional in terms of αvß3 and IL12-receptor recognition. Low-dose Iso1/Au/IL12, equivalent to 18-75 pg of IL12, induces antitumor effects in murine models of fibrosarcomas and mammary adenocarcinomas, with no evidence of toxicity. Equivalent doses of Au/IL12 (a nanodrug lacking Iso1) fail to delay tumor growth, whereas 15 000 pg of free IL12 is necessary to achieve similar effects. Iso1/Au/IL12 significantly increases tumor infiltration by innate immune cells, such as NK and iNKT cells, monocytes, and neutrophils. NK cell depletion completely inhibits its antitumor effects. Low-dose Iso1/Au/IL12 can also increase the therapeutic efficacy of adoptive T-cell therapy in mice with autochthonous prostate cancer. These findings indicate that coupling IL12 to isoDGR-tagged nanogold is a valid strategy for enhancing its therapeutic index and sustaining adoptive T-cell therapy.

Expression analysis of HMGB1 in histological samples of malignant pleural mesothelioma.

AIMS: High mobility group box 1 (HMGB1) is a chromatin structural protein, expressed ubiquitously in the nuclei of mammalian cells. When transported extracellularly, it acts as a tumour suppressor and oncogenic protein. In malignant pleural mesothelioma (MPM), high serum levels of HMGB1 have been related to a poor prognosis. Conversely, the significance of HMGB1 expression in MPM tissues is still unclear. METHODS AND RESULTS: Biopsy samples from 170 patients with MPM were assessed by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) to evaluate HMGB1 protein and gene expression. The expression level of HMGB1 protein was scored using a semiquantitative system that sums the intensity (0-3) and the percentage (from 0 to 4) of positively stained cells in nuclei, cytoplasm and in both. The final score was considered as high (>3) or low (<3) expression. Gene expression levels were calculated using the ΔΔCt method. High expression levels of HMGB1 as total (P = 0.0011) and cytoplasmic score (P = 0.0462) were related to a worse disease-specific survival (DSS) in the entire cohort and in the clinicopathological subgroups. No significant correlation was found between HMGB1 gene expression and DSS. CONCLUSIONS: These findings indicate that HMGB1 may be a useful prognostic biomarker in MPM when detected by immunohistochemistry. Conversely, as it is also expressed in normal and reactive mesothelial cells, HMGB1 cannot be considered a diagnostic biomarker in histological samples of mesothelioma.

Programmed cell death 1 ligand 1 (PD-L1) expression is associated with poor prognosis of malignant pleural mesothelioma patients with good performance status.

Malignant pleural mesothelioma (MPM) is often associated with a poor prognosis and options for the treatment of this disease are few. To date, the important role of the immune microenvironment in modifying the disease natural history is well established. The programmed cell death pathway (PD-1/PD-L1) limits the T lymphocyte activation in peripheral tissues when an inflammatory response occurs, and controls the tumour immune escape. PD-L1 is broadly expressed in several malignant tumours and associated with poor clinical outcomes. Thus, the aim of our study is to investigate the potential role of PD-L1 expression in MPM prognosis. Biopsy samples from 198 patients diagnosed with MPM were examined by immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR) to evaluate PD-L1 protein and gene expression. For PD-L1 protein expression we consider at least 5% membranous staining as positive. Gene expression levels were calculated with ΔΔCt method. Positive expression of PD-L1 by IHC was correlated with worse overall survival (OS; p=0.0225) in MPM patients. PD-L1 positive status was correlated with worse OS in the subgroup of patients with ECOG score <2 (p=0.0004, n=129) and these data were confirmed by multivariate analysis. No significant correlation was found between PD-L1 gene expression and OS. Our results show that PD-L1 evaluated by IHC assay may be a prognostic biomarker for MPM patients with good performance status.

Improving the antitumor activity of R-CHOP with NGR-hTNF in primary CNS lymphoma: final results of a phase 2 trial.

Rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) is the standard treatment of diffuse large B-cell lymphoma (DLBCL). Primary DLBCL of the central nervous system (CNS) (primary central nervous system lymphoma [PCNSL]) is an exception because of the low CNS bioavailability of related drugs. NGR-human tumor necrosis factor (NGR-hTNF) targets CD13+ vessels, enhances vascular permeability and CNS access of anticancer drugs, and provides the rationale for the treatment of PCNSL with R-CHOP. Herein, we report activity and safety of R-CHOP preceded by NGR-hTNF in patients with PCNSL relapsed/refractory to high-dose methotrexate-based chemotherapy enrolled in a phase 2 trial. Overall response rate (ORR) was the primary endpoint. A sample size of 28 patients was considered necessary to demonstrate improvement from 30% to 50% ORR. NGR-hTNF/R-CHOP would be declared active if ≥12 responses were recorded. Treatment was well tolerated; there were no cases of unexpected toxicities, dose reductions or interruptions. NGR-hTNF/R-CHOP was active, with confirmed tumor response in 21 patients (75%; 95% confidence interval, 59%-91%), which was complete in 11. Seventeen of the 21 patients with response to treatment received consolidation (ASCT, WBRT, and/or lenalidomide maintenance). At a median follow-up of 21 (range, 14-31) months, 5 patients remained relapse-free and 6 were alive. The activity of NGR-hTNF/R-CHOP is in line with the expression of CD13 in both pericytes and endothelial cells of tumor vessels. High plasma levels of chromogranin A, an NGR-hTNF inhibitor, were associated with proton pump inhibitor use and a lower remission rate, suggesting that these drugs should be avoided during TNF-based therapy. Further research on this innovative approach to CNS lymphomas is warranted. The trial was registered as EudraCT: 2014-001532-11.

Prognostic impact of a 3-MicroRNA signature in cytological samples of small cell lung cancer.

BACKGROUND: Small cell lung cancer (SCLC) is a highly aggressive neoplasm that accounts for approximately 10% to 15% of lung cancers. In most cases, the diagnosis relies on cytology and needs to be confirmed by immunohistochemistry. Although several genetic and molecular abnormalities have been recorded, molecular markers able to predict the prognosis are still lacking. MicroRNA (miRNA) signatures have been recently proposed as useful biomarkers in lung cancer because of their high stability during standard sample processing. METHODS: Cytological samples for 50 patients with SCLC were collected from primary tumors (n = 25) and metastases (n = 25) by means of fine-needle aspiration (FNA) or bronchial washing (BW); they were fixed in ethanol (FNA) or Duboscq-Brazil fluid (BW). The 3-miRNA panel expression (miR-192, miR-200c, and miR-205) was quantified with a TaqMan polymerase chain reaction miRNA assay and was compared with overall survival (OS) and clinicopathological data. RESULTS: All samples had sufficient RNA for the miRNA expression analysis to be performed, regardless of the sample source or the fixative medium. Patients with a low expression level of the 3-miRNA panel were associated with better OS in univariate (P = .032) and multivariate analyses (P = .022). Moreover, in the group of patients older than the mean age of our cohort (65.8 years), a significant OS advantage (P = .013) was seen for patients with a low expression level of the 3-miRNA panel. CONCLUSIONS: A specific 3-miRNA signature is potentially useful for predicting survival for patients with SCLC, and it may be feasible with cytological samples taken during standard diagnostic procedures. Cancer Cytopathol 2016;124:621-9. © 2016 American Cancer Society.

Human malignant mesothelioma is recapitulated in immunocompetent BALB/c mice injected with murine AB cells.

Malignant Mesothelioma is a highly aggressive cancer, which is difficult to diagnose and treat. Here we describe the molecular, cellular and morphological characterization of a syngeneic system consisting of murine AB1, AB12 and AB22 mesothelioma cells injected in immunocompetent BALB/c mice, which allows the study of the interplay of tumor cells with the immune system. Murine mesothelioma cells, like human ones, respond to exogenous High Mobility Group Box 1 protein, a Damage-Associated Molecular Pattern that acts as a chemoattractant for leukocytes and as a proinflammatory mediator. The tumors derived from AB cells are morphologically and histologically similar to human MM tumors, and respond to treatments used for MM patients. Our system largely recapitulates human mesothelioma, and we advocate its use for the study of MM development and treatment.