An actionable axis linking NFATc2 to EZH2 controls the EMT-like program of melanoma cells.

Discovery of new actionable targets and functional networks in melanoma is an urgent need as only a fraction of metastatic patients achieves durable clinical benefit by targeted therapy or immunotherapy approaches. Here we show that NFATc2 expression is associated with an EMT-like transcriptional program and with an invasive melanoma phenotype, as shown by analysis of melanoma cell lines at the mRNA and protein levels, interrogation of the TCGA melanoma dataset and characterization of melanoma lesions by immunohistochemistry. Gene silencing or pharmacological inhibition of NFATc2 downregulated EMT-related genes and AXL, and suppressed c-Myc, FOXM1, and EZH2. Targeting of c-Myc suppressed FOXM1 and EZH2, while targeting of FOXM1 suppressed EZH2. Inhibition of c-Myc, or FOXM1, or EZH2 downregulated EMT-related gene expression, upregulated MITF and suppressed migratory and invasive activity of neoplastic cells. Stable silencing of NFATc2 impaired melanoma cell proliferation in vitro and tumor growth in vivo in SCID mice. In NFATc2+ EZH2+ melanoma cell lines pharmacological co-targeting of NFATc2 and EZH2 exerted strong anti-proliferative and pro-apoptotic activity, irrespective of BRAF or NRAS mutations and of BRAF inhibitor resistance. These results provide preclinical evidence for a role of NFATc2 in shaping the EMT-like melanoma phenotype and reveal a targetable vulnerability associated with NFATc2 and EZH2 expression in melanoma cells belonging to different mutational subsets.

Early Effector T Lymphocytes Coexpress Multiple Inhibitory Receptors in Primary Non-Small Cell Lung Cancer.

Clinical efficacy of PD-1/PD-L1 targeting relies upon the reactivation of tumor-specific but functionally impaired PD-1+ T cells present before therapy. Thus, analyzing early-stage primary tumors may reveal the presence of T cells that are not yet functionally impaired. In this study, we report that activated (HLA-DR+) T cells with an effector memory (TEM) profile are enriched in such lesions. Tumor-infiltrating lymphocytes coexpressed PD-1 with the inhibitory receptors TIM-3, CTLA-4, LAG-3, and TIGIT, but also displayed a recently activated, nonexhausted phenotype. We also identified a subset of CD8+PD-1+FOXP3+ T lymphocytes at the earliest phase of functional differentiation after priming, termed "early effector cells" (EEC), which also exhibited an activated nonexhausted phenotype, but was less differentiated and associated with coexpression of multiple inhibitory receptors. In response to autologous tumor, EECs upregulated CD107a, produced IL2 and IFNγ, and were competent for differentiation. The identification of EECs marked by inhibitory receptor expression at tumor sites will enable investigations of early stages of adaptive antitumor immunity, as well as support the rationale for administering immunotherapy in early-stage non-small cell lung cancer. Cancer Res; 77(4); 851-61. ©2016 AACR.

Sema6A and Mical1 control cell growth and survival of BRAFV600E human melanoma cells.

We used whole genome microarray analysis to identify potential candidate genes with differential expression in BRAFV600E vs NRASQ61R melanoma cells. We selected, for comparison, a peculiar model based on melanoma clones, isolated from a single tumor characterized by mutually exclusive expression of BRAFV600E and NRASQ61R in different cells. This effort led us to identify two genes, SEMA6A and MICAL1, highly expressed in BRAF-mutant vs NRAS-mutant clones. Real-time PCR, Western blot and immunohistochemistry confirmed preferential expression of Sema6A and Mical1 in BRAFV600E melanoma. Sema6A is a member of the semaphorin family, and it complexes with the plexins to regulate actin cytoskeleton, motility and cell proliferation. Silencing of Sema6A in BRAF-mutant cells caused cytoskeletal remodeling, and loss of stress fibers, that in turn induced cell death. Furthermore, Sema6A depletion caused loss of anchorage-independent growth, inhibition of chemotaxis and invasion. Forced Sema6A overexpression, in NRASQ61R clones, induced anchorage-independent growth, and a significant increase of invasiveness. Mical1, that links Sema/PlexinA signaling, is also a negative regulator of apoptosis. Indeed, Mical-1 depletion in BRAF mutant cells restored MST-1-dependent NDR phosphorylation and promoted a rapid and massive NDR-dependent apoptosis. Overall, our data suggest that Sema6A and Mical1 may represent new potential therapeutic targets in BRAFV600E melanoma.

Molecular subtyping of metastatic melanoma based on cell ganglioside metabolism profiles.

BACKGROUND: In addition to alterations concerning the expression of oncogenes and onco-suppressors, melanoma is characterized by the presence of distinctive gangliosides (sialic acid carrying glycosphingolipids). Gangliosides strongly control cell surface dynamics and signaling; therefore, it could be assumed that these alterations are linked to modifications of cell behavior acquired by the tumor. On these bases, this work investigated the correlations between melanoma cell ganglioside metabolism profiles and the biological features of the tumor and the survival of patients. METHODS: Melanoma cell lines were established from surgical specimens of AJCC stage III and IV melanoma patients. Sphingolipid analysis was carried out on melanoma cell lines and melanocytes through cell metabolic labeling employing [3-3H]sphingosine and by FACS. N-glycolyl GM3 was identified employing the 14 F7 antibody. Gene expression was assayed by Real Time PCR. Cell invasiveness was assayed through a Matrigel invasion assay; cell proliferation was determined through the soft agar assay, MTT, and [3H] thymidine incorporation. Statistical analysis was performed using XLSTAT software for melanoma hierarchical clustering based on ganglioside profile, the Kaplan-Meier method, the log-rank (Mantel-Cox) test, and the Mantel-Haenszel test for survival analysis. RESULTS: Based on the ganglioside profiles, through a hierarchical clustering, we classified melanoma cells isolated from patients into three clusters: 1) cluster 1, characterized by high content of GM3, mainly in the form of N-glycolyl GM3, and GD3; 2) cluster 2, characterized by the appearance of complex gangliosides and by a low content of GM3; 3) cluster 3, which showed an intermediate phenotype between cluster 1 and cluster 3. Moreover, our data demonstrated that: a) a correlation could be traced between patients' survival and clusters based on ganglioside profiles, with cluster 1 showing the worst survival; b) the expression of several enzymes (sialidase NEU3, GM2 and GM1 synthases) involved in ganglioside metabolism was associated with patients' survival; c) melanoma clusters showed different malignant features such as growth in soft agar, invasiveness, expression of anti-apoptotic proteins. CONCLUSIONS: Ganglioside profile and metabolism is strictly interconnected with melanoma aggressiveness. Therefore, the profiling of melanoma gangliosides and enzymes involved in their metabolism could represent a useful prognostic and diagnostic tool.

NFATc2 is a potential therapeutic target in human melanoma.

The identification of intracellular signaling pathways that promote cell proliferation and resistance to cell death may lead to the development of improved treatment for advanced melanoma. Here we show that the calcineurin/nuclear factor of activated T cells c2 (NFATc2) pathway has an antiapoptotic role in melanoma cells. Expression of NFATc2 was constitutive in vitro and in vivo in human melanoma, and cyclosporin A (CsA) treatment of melanoma cells led to downmodulation of NFATc2. Inhibition of the calcineurin/NFAT pathway by CsA, or by NFATc2 silencing, led to modulation of cell cycle inhibitors and apoptosis-related proteins such as Apollon, and promoted caspase-dependent apoptosis of neoplastic cells. Calcineurin/NFATc2 targeting significantly enhanced melanoma cell death induced by antitumor agents, such as MEK- or BRAF(V600E)-specific inhibitors, and tumor necrosis factor-related apoptosis-inducing ligand, which trigger the intrinsic or extrinsic pathway of apoptosis, respectively. These findings identify NFATc2 as a potential therapeutic target in melanoma.

Vaccination with autologous tumor-loaded dendritic cells induces clinical and immunologic responses in indolent B-cell lymphoma patients with relapsed and measurable disease: a pilot study.

Eighteen relapsed patients with measurable indolent non-Hodgkin lymphoma (NHL) were vaccinated with dendritic cells (DCs) loaded with killed autologous tumor cells. Six patients had objective clinical responses including 3 continuous complete responses (CRs) and 3 partial responses (PRs), with a median follow up of 50.5 months. Eight patients had stable disease, whereas 4 had progressive disease. Clinical responses were significantly associated with a reduction in CD4(+)CD25(+)FOXP3(+) regulatory T cells, an increase in CD3(-)CD56(dim)CD16(+) natural killer (NK) cells, and maturation of lymphocytes to the effector memory stage in either postvaccination peripheral blood or tumor specimen samples. In partial responding patients, vaccination significantly boosted the IFN-gamma-producing T-cell response to autologous tumor challenge. In one HLA-A*0201(+) patient who achieved CR, IL-4 release by circulating T cells in response to tumor-specific IgH-encoded peptides was also documented. Immunohistochemical analysis of tumor biopsies using biotin-conjugated autologous serum samples revealed a tumor-restricted humoral response only in the postvaccination serum from responding patients. Collectively these results demonstrate that vaccination with tumor-loaded DCs may induce both T- and B-cell responses and produces clinical benefits in indolent NHL patients with measurable disease. This study is registered with the Istituto Superiore di Sanità: http://www.iss.it with protocol number 7578-PRE 21-801.

Regulation of breast cancer response to chemotherapy by fibulin-1.

Doxorubicin treatment was found to augment the expression of the extracellular matrix (ECM) protein fibulin-1 in cultured human breast cancer cell lines and in MDA-MB-361 tumors grown in athymic mice. Doxorubicin was also found to augment tumor expression of the fibulin-1-binding proteins fibronectin and laminin-1. Growth of breast cancer cell lines on Matrigel, an ECM extract containing fibulin-1 and laminin-1, resulted in lower levels of doxorubicin-induced apoptosis as compared with controls. Moreover, tumors formed by injection of athymic mice with MDA-MB-361 cells mixed with Matrigel were significantly more doxorubicin resistant and displayed lower levels of apoptosis compared with those that formed in the absence of Matrigel. Monoclonal antibodies against fibulin-1 reversed Matrigel-dependent doxorubicin resistance. Furthermore, small interfering RNA-mediated suppression of fibulin-1 expression in breast cancer cells resulted in a 10-fold increase in doxorubicin sensitivity as compared with control cells. Together, these findings point to a role for fibulin-1 in breast cancer chemoresistance.

Skewed T-cell differentiation in patients with indolent non-Hodgkin lymphoma reversed by ex vivo T-cell culture with gammac cytokines.

The unfavorable clinical evolution in indolent non-Hodgkin lymphomas suggests defective control of neoplastic growth by the immune system. To address this issue, we evaluated phenotype, function, and maturation profile of CD4(+) and CD8(+) T cells from peripheral-blood, lymph nodes, or bone marrow of patients with B-cell non-Hodgkin lymphoma (NHL) at diagnosis. T cells from these patients frequently showed an activated but apoptosis-prone phenotype with low frequency of tumor-reactive T cells showing a TH2/Tc2 functional profile in the response to autologous tumor. In peripheral blood or in lymph nodes and bone marrow, and, in comparison to healthy donors, patients' T cells showed a skewed differentiation toward Tnaive and Tcentral memory stages, with low expression of granzyme B and perforin. T-cell culture with autologous tumor in the presence of IL-2, IL-15, and autologous bone marrow-derived cells led to massive T-cell expansion and to differentiation of cytotoxic factor(+) CD8(+) T cells releasing IFN-gamma and killing autologous B-cell tumor in an HLA-class I-restricted fashion. These results suggest impaired T-cell differentiation to effector stage in patients with B-cell NHL, but indicate that T-cell responsiveness to gammac cytokines is retained, thus allowing to promote generation of antitumor T cells for immune intervention.

Boosting T cell-mediated immunity to tyrosinase by vaccinia virus-transduced, CD34(+)-derived dendritic cell vaccination: a phase I trial in metastatic melanoma.

PURPOSE: Six American Joint Committee on Cancer stage IV melanoma patients were enrolled into a Phase I study of vaccination with autologous CD34(+)-derived dendritic cells transduced with a modified vaccinia Ankara virus encoding human tyrosinase gene (MVA-hTyr). EXPERIMENTAL DESIGN: Patients received a first intravenous injection of 1 x 10(8) MVA-hTyr-transduced dendritic cells, followed by three s.c. injections at a 14-day interval. RESULTS: Treatment was well tolerated, except for low-grade fever (three of six patients), mild erythema at injection site (five of six), and vitiligo (two of six). A partial response, involving shrinkage of an s.c. nodule, later surgically removed, was observed in 1 patient, who then remained disease-free (>850 days). By human lymphocyte antigen tetramer analysis, significant and often long-lasting increases in frequency of T cells directed to tyrosinase(368-376) but not to gp100(209-217) were documented in periphery of 4 of 5 HLA-A*0201+ patients, a few days after vaccine administration. In addition, maturation phenotype of tyrosinase-specific T cell shifted toward the T effector memory/T terminally differentiate stages (CCR7(-)CD45RA(-/+)) in synchrony with the T-cell frequency peaks. By enzyme-linked immunospot in peripheral blood of five HLA-A*0201+ patients, we found that the vaccine could induce interferon gamma-releasing effector cells directed to HLA-A*0201/tyrosinase(368-376) and to vaccinia virus HLA-A*0201/H3L(184-192) epitopes. Moreover, an interferon gamma response after vaccination was elicited even against the HLA-DRB1-1501/tyrosinase(386-406) epitope in one out of two HLA-A* DRB1-01501+ patients. CONCLUSIONS: These results indicate that vaccination with MVA-hTyr-transduced dendritic cells is well tolerated, can possibly produce clinical responses, and activates tyrosinase- and vaccinia virus-specific T cells in vivo. These data suggest a broad utility of the MVA vector for targeting tumor-associated antigens to dendritic cells for tumor immunotherapy.

Immunological and pathobiological roles of fibulin-1 in breast cancer.

Fibulin-1 (Fbln-1) is an immunogenic breast cancer-related glycoprotein identified by serological analysis of cDNA expression library (SEREX) strategy. Here, we show that dendritic cells from two breast cancer patients elicited a CD4(+)-mediated T-cell response to Fbln-1 presentation. In both patients, an antibody response to Fbln-1 was also found. By contrast, a Fbln-1-seronegative patient and a weakly seropositive patient demonstrated no such T-cell response. Analysis of human breast cancers for Fbln-1 RNA and protein expression revealed the presence of Fbln-1C and -1D variants. Fbln-1 was detected in the cytoplasm and at the cell surface of different human breast carcinoma cell lines. Immunohistochemical analysis of 528 archival primary breast carcinomas showed the expression of Fbln-1 in 35% of the cases. When the immunohistochemical findings were compared against pathobiological information associated with each specimen, an inverse relationship between Fbln-1 and cathepsin D expression was observed (P=0.04). Furthermore, even though long-term survival was similar between Fbln-1-positive and -negative cases, the survival of Fbln-1-positive cases improved when a lymphoid infiltrate was present at the tumour site. Taken together, our findings of an Fbln-1-specific immunity and the improved survival associated with Fbln-1 expression in the presence of lymphoid infiltration point to a role of Fbln-1 in tumour immunosurveillance.