Search

Cancer-associated fibroblasts (CAFs) play a key role in cancer progression and treatment outcome. Here, we elucidate the yet unresolved intra-tumoral CAF variety in three skin cancer types at molecular and spatial single-cell resolution in a large cohort. We show that two out of three CAF subtypes contribute to tumor immune surveillance with distinct mechanisms. Matrix CAFs (mCAFs), a previously unknown subtype present in early-stage tumors, ensheath tumor nests and synthesize extracellular-matrix to prevent T cell invasion. Immuno CAFs (iCAFs), which express proinflammatory and immunomodulatory factors, are only detected in high abundance in aggressive tumors. Strikingly, iCAFs but not tumor cells are the exclusive celltype producing chemokines and, thus, play a key role in immune cell recruitment and activation. Mechanistically, we show that cancer cells transform adjacent healthy fibroblasts into cytokine-expressing iCAFs, which subsequently recruit immune cells and modulate the immune response. In conclusion, targeting CAF variants holds promise for improved efficacy of immunotherapy.Statement of significance:While it is accepted that fibroblasts affect cancer progression, the underlying molecular programs remain unclear. We unravel a multi-step cascade demonstrating that tumor cells transform healthy fibroblasts into CAFs, which critically impact immune surveillance via iCAFs being the exclusive source of chemokines and mCAFs promoting T cell exclusion.

Supplementary Table S4 from Gene Expression Changes in an Animal Melanoma Model Correlate with Aggressiveness of Human Melanoma Metastases

Supplementary Figures S1-S2 from Gene Expression Changes in an Animal Melanoma Model Correlate with Aggressiveness of Human Melanoma Metastases

Metastasis is the deadliest phase of cancer progression. Experimental models using immunodeficient mice have been used to gain insights into the mechanisms of metastasis. We report here the identification of a “metastasis aggressiveness gene expression signature” derived using human melanoma cells selected based on their metastatic potentials in a xenotransplant metastasis model. Comparison with expression data from human melanoma patients shows that this metastasis gene signature correlates with the aggressiveness of melanoma metastases in human patients. Many genes encoding secreted and membrane proteins are included in the signature, suggesting the importance of tumor-microenvironment interactions during metastasis. (Mol Cancer Res 2008;6(5):760–9)

Cutaneous B-cell lymphomas (CBL) comprise a diverse group of diseases with variable clinical course and prognosis. The cellular and molecular mechanisms underlying the pathogenesis of CBL remain ill-defined. Here we performed single-cell RNA sequencing combined with B-cell and T-cell receptor sequencing in three distinct CBL entities. In contrast to benign cutaneous pseudolymphomas and healthy skin, each CBL variant contained a single dominant B-cell clone. In marginal zone lymphoproliferative disorder (MZLPD), expanded clones generally showed terminal differentiation along a physiological trajectory towards plasma cells and displayed transcriptomic profiles indistinguishable from the benign polyclonal bystander B-cells. Follicle center lymphoma (FCL) clones also exhibited a canonical B-cell marker profile but consisted of more homogeneous populations of proliferating and nonproliferating germinal center (GC) B-cell-like phenotypes. In the most aggressive CBL, diffuse large B-cell lymphoma, leg type (DCBCL-LT), cells revealed multiple non-physiological marker profiles as well as aberrant proliferative activity beyond conventional GC-like cells. Fibroblasts in MZLPD, FCL and pseudolymphomas, but not DLBCL-LT, expressed the classical chemotactic chemokineCXCL13. These data suggest that in cutaneous B-cell disorders other than DLBCL-LT, physiological immune circuits are primarily operative, consistent with their overall indolent behavior.Key PointsThis is the first comprehensive molecular map of primary cutaneous B-cell lymphoproliferative disorders.Differences between entities were primarily geared by the expanded B-cell clone and less by other immune or stromal cells.

Immediate-type hypersensitivity reactions (IHRs) to carboplatin (CA) are most commonly reported in ovarian cancer patients. A 54-year-old woman with stage IV melanoma suffering from metastasis in the entire right lower extremity was presented to our allergy outpatient clinic for diagnostic work-up due to an anaphylactic reaction with palmoplantar erythema, conjunctivitis along with facial erythema, and an incipient decrease in blood pressure during a chemotherapy regimen with dacarbazine and carboplatin upon re-administration. A subsequently carried out allergological work-up with skin testing (ST) revealed CA to be the culprit drug, whereas cisplatin (CI) was confirmed to be a safe alternative for the patient for following treatments. Here, we report a case of an IHR to carboplatin in a melanoma patient, with CI serving as a safe alternative diagnosed by skin testing.Allergische Reaktionen vom Soforttyp auf Carboplatin werden meist bei Patientinnen mit Ovarialkarzinom beschrieben. Eine 54-jährige Patientin mit einem Melanom im Stadium IV und einer Metastasierung im Bereich der gesamten rechten unteren Extremität wurde in unserer Allergieambulanz zur diagnostischen Abklärung vorstellig. Anamnestisch hatte sie während einer Chemotherapie mit Dacarbazin und Carboplatin nach neuerlicher Verabreichung eine anaphylaktische Reaktion mit einem palmoplantaren und fazialen Erythem, einer Konjunktivitis sowie beginnendem Blutdruckabfall entwickelt. Die allergologische Abklärung mit Hauttestungen konnte Carboplatin als Auslöser identifizieren. Wir berichten hier über einen Fall einer allergischen Soforttyp-Reaktion auf Carboplatin bei einer Melanompatientin, die mittels Hauttestungen bestätigt werden konnte, während sich Cisplatin hierbei als sichere Alternative erwies.

Tumor associated inflammation predicts response to immune checkpoint blockade in human melanoma. Current theories on regulation of inflammation center on anti-tumor T cell responses. Here we show that tumor associated B cells are vital to melanoma associated inflammation. Human B cells express pro- and anti-inflammatory factors and differentiate into plasmablast-like cells when exposed to autologous melanoma secretomes in vitro. This plasmablast-like phenotype can be reconciled in human melanomas where plasmablast-like cells also express T cell-recruiting chemokines CCL3, CCL4, CCL5. Depletion of B cells in melanoma patients by anti-CD20 immunotherapy decreases tumor associated inflammation and CD8+ T cell numbers. Plasmablast-like cells also increase PD-1+ T cell activation through anti-PD-1 blockade in vitro and their frequency in pretherapy melanomas predicts response and survival to immune checkpoint blockade. Tumor associated B cells therefore orchestrate and sustain melanoma inflammation and may represent a predictor for survival and response to immune checkpoint blockade therapy., The regulation of tumor inflammation is incompletely understood and the role of B cells is unclear. Here, the authors show that a specific subtype of B cells is induced in melanoma and required to recruit T lymphocytes and elicit inflammation.

AIMS: Immune checkpoint inhibitors have become a successful treatment in metastatic melanoma. The high response rates in a subset of patients suggest that a sensitive companion diagnostic test is required. The predictive value of programmed death ligand 1 (PD-L1) staining in melanoma has been questioned due to inconsistent correlation with clinical outcome. Whether this is due to predictive irrelevance of PD-L1 expression or inaccurate assessment techniques remains unclear. The aim of this study was to develop a standardised digital protocol for the assessment of PD-L1 staining in melanoma and to compare the output data and reproducibility to conventional assessment by expert pathologists. METHODS AND RESULTS: In two cohorts with a total of 69 cutaneous melanomas, a highly significant correlation was found between pathologist-based consensus reading and automated PD-L1 analysis (r = 0.97, P < 0.0001). Digital scoring captured the full diagnostic spectrum of PD-L1 expression at single cell resolution. An average of 150 472 melanoma cells (median 38 668 cells; range = 733-1 078 965) were scored per lesion. Machine learning was used to control for heterogeneity introduced by PD-L1-positive inflammatory cells in the tumour microenvironment. The PD-L1 image analysis protocol showed excellent reproducibility (r = 1.0, P < 0.0001) when carried out on independent workstations and reduced variability in PD-L1 scoring of human observers. When melanomas were grouped by PD-L1 expression status, we found a clear correlation of PD-L1 positivity with CD8-positive T cell infiltration, but not with tumour stage, metastasis or driver mutation status. CONCLUSION: Digital evaluation of PD-L1 reduces scoring variability and may facilitate patient stratification in clinical practice.

B cells often infiltrate the microenvironment of human tumors. B cells can both positively and negatively regulate antitumor immune responses. In several human cancers, higher numbers of CD20(+) TAB are associated with a favorable prognosis, whereas in human primary melanomas, this association is contentious. In this study, we determined the association of TAB numbers in cutaneous primary melanoma tissue samples and patients' overall survival. The CD20 immunohistochemistry on archival nonmetastasized and metastasized cutaneous primary melanoma tissues from 2 independent patient cohorts was performed. One cohort was used in class comparison for metastasis, the most important prognostic factor for overall survival, and the other cohort for a subsequent survival analysis. Survival association was further validated with RNA data from a third independent cohort. Whole tissue sections were read automatically via quantitative digital imaging and analysis. Survival data were analyzed by Cox proportional hazard modeling. We discovered that cutaneous primary melanomas without metastasis contain significantly more TAB than primary melanomas that had metastasized. At time of first diagnosis, a higher number of TAB is associated with a significantly better overall survival in patients with cutaneous primary melanomas of >1 mm Breslow depth. Also, higher CD20/CD19 tumor mRNA levels are correlated with a significantly better overall survival. Thus, our data support TAB numbers as a prognostic biomarker in cutaneous primary melanoma patients with a tumor of >1 mm Breslow depth. For a survey in larger studies, whole tissue section analysis seems to be key to accurate assessment of TAB numbers.

In melanoma, therapies with inhibitors to oncogenic BRAFV600E are highly effective but responses are often short-lived due to the emergence of drug-resistant tumor subpopulations. We describe here a mechanism of acquired drug resistance through the tumor microenvironment, which is mediated by human tumor-associated B cells. Human melanoma cells constitutively produce the growth factor FGF-2, which activates tumor-infiltrating B cells to produce the growth factor IGF-1. B-cell-derived IGF-1 is critical for resistance of melanomas to BRAF and MEK inhibitors due to emergence of heterogeneous subpopulations and activation of FGFR-3. Consistently, resistance of melanomas to BRAF and/or MEK inhibitors is associated with increased CD20 and IGF-1 transcript levels in tumors and IGF-1 expression in tumor-associated B cells. Furthermore, first clinical data from a pilot trial in therapy-resistant metastatic melanoma patients show anti-tumor activity through B-cell depletion by anti-CD20 antibody. Our findings establish a mechanism of acquired therapy resistance through tumor-associated B cells with important clinical implications., Resistance to BRAFV600E inhibitors often occurs in melanoma patients. Here, the authors describe a potential mechanism of acquired drug resistance mediated by tumor-associated B cells-derived IGF-1.

Melanoma is a heterogeneous tumor with different subpopulations showing different proliferation rates. Slow-cycling cells were previously identified in melanoma, but not fully biologically characterized. Using the label-retention method, we identified a subpopulation of slow-cycling cells, defined as label-retaining cells (LRC), with strong invasive properties. We demonstrate through live imaging that LRC are leaving the primary tumor mass at a very early stage and disseminate to peripheral organs. Through global proteome analyses, we identified the secreted protein SerpinE2/protease nexin-1 as causative for the highly invasive potential of LRC in melanomas.

SummaryOncogene-induced senescence is characterized by a stable cell growth arrest, thus providing a tumor suppression mechanism. However, the underlying mechanisms for this phenomenon remain unknown. Here, we show that a decrease in deoxyribonucleotide triphosphate (dNTP) levels underlies oncogene-induced stable senescence-associated cell growth arrest. The decrease in dNTP levels is caused by oncogene-induced repression of ribonucleotide reductase subunit M2 (RRM2), a rate-limiting protein in dNTP synthesis. This precedes the senescence-associated cell-cycle exit and coincides with the DNA damage response. Consistently, RRM2 downregulation is both necessary and sufficient for senescence. Strikingly, suppression of nucleotide metabolism by RRM2 repression is also necessary for maintenance of the stable senescence-associated cell growth arrest. Furthermore, RRM2 repression correlates with senescence status in benign nevi and melanoma, and its knockdown drives senescence of melanoma cells. These data reveal the molecular basis whereby the stable growth arrest of oncogene-induced senescence is established and maintained through suppression of nucleotide metabolism.

Current therapy approaches in melanoma targeting have met with the development of resistance and tumour recurrence with a more aggressive phenotype. In a quest for alternative therapy targets, we had previously identified Signal Sequence Receptor 2 (SSR2) as a gene with high expression in a subgroup of human primary melanomas. Now we show that SSR2 exerts a prosurvival functionality in human melanoma cells and that high expression levels of SSR2 are associated with an unfavourable disease outcome in primary melanoma patients. Consistent with SSR's role in translocation of proteins from the ribosome across the endoplasmic reticulum (ER) membrane, our data supports induction of SSR2 as a part of the ER stress response. This response included SSR2 upregulation upon development of therapy resistance to BRAF inhibitors, as well as the dependency of cell survival of BRAF inhibitor-resistant melanoma cells on SSR2. Complementary gain and loss of function data showed the Unfolded Protein Response (UPR) to ER stress as an inducer of SSR2 via transcriptional regulation through X-Box Binding Protein 1s (XBP1s) and support an ER stress-UPR-Transcription Factor XBP1s-SSR2 response axis in human melanocytic cells. Together with its dispensability for survival in normal human cells, these data propose SSR2 as a potential therapeutic target in (therapy-resistant) human melanoma.

Background Activity of both c-Jun and cyclin D1 is deemed critical for melanoma cell proliferation. This functionality is corroborated by frequently elevated expression and activity of these proteins in human melanomas. Correspondingly, alleviating c-Jun and cyclin D1 function is vital to the success of antimelanoma therapeutics. Objectives To understand the role of the c-Jun N-terminal kinase (JNK) signalling pathway in melanoma cell proliferation and survival. Methods The effect of JNK inhibitors SP600125 and JNK-IN-8 on the proliferation and survival of genetically highly representative human melanoma cell lines was studied in assays of proliferation and apoptosis. Changes in c-Jun and cyclin D1 protein and mRNA levels in response to JNK and mitogen-activated protein kinase kinase (MEK) inhibition were investigated through immunoblotting and quantitative reverse-transcription polymerase chain reaction. The effects of JNK and MEK inhibitors on cell-cycle distribution were assessed by flow cytometry. Results We demonstrate the requirement of JNK signalling in melanoma cell proliferation and survival. While JNK inhibition suppressed the expression and activity of c-Jun, it failed to suppress cyclin D1 levels. Consistently with its inability to downregulate cyclin D1, JNK inhibition failed to induce G1 arrest. In contrast, the blockade of MEK-extracellular signal-regulated kinase (ERK) signalling, although unable to suppress c-Jun activity and expression, paradoxically abated cyclin D1 levels and triggered G1 arrest. This previously unreported dual disconnect between JNK-cyclin D1 and ERK-c-Jun levels was confirmed by concomitant JNK and BRAF inhibition, which suppressed both c-Jun and cyclin D1 levels and exhibited a heightened antiproliferative response. Conclusions Dual disjunction between JNK-cyclin D1 and ERK-c-Jun signalling forms the basis for further investigation of combined JNK and MAPK signalling blockade as a more effective therapeutic approach in human melanoma.

Melanoma patients develop resistance to both chemotherapy and targeted-therapy drugs. Promising preclinical and clinical results with immune checkpoint inhibitors using antibodies directed against cytotoxic T-lymphocyte-associated protein 4 and programmed cell death protein 1 have re-energized the field of immune-based therapies in melanoma. However, similar to chemotherapy or targeted therapies, immune checkpoint blockade responds in only subsets of melanoma patients. A number of factors, including gene mutations, altered cell-signaling pathways and tumor heterogeneity can contribute to therapy resistance. Recent studies have highlighted the role of inflammatory tumor microenvironment on therapy resistance of cancer cells. Cancer cells either alone or in conjunction with the tumor stroma can contribute to an inflammatory microenvironment. Multimodal approaches of targeting the tumor microenvironment, in addition to malignant cells, may be necessary for better therapy responses.

Resistance to BRAF(V600E) inhibitors is associated with reactivation of mitogen-activated protein kinase (MAPK) signaling at different levels in melanoma. To identify downstream effectors of MAPK signaling that could be used as potential additional therapeutic targets for BRAF(V600E) inhibitors, we used hTERT/CDK4R24C/p53DD-immortalized primary human melanocytes genetically modified to ectopically express BRAF ( V600E ) or NRAS ( G12D ) and observed induction of the AP-1 transcription factor family member c-Jun. Using a dominant negative approach, in vitro cell proliferation assays, western blots, and flow cytometry showed that MAPK signaling via BRAF(V600E) promotes melanoma cell proliferation at G1 through AP-1-mediated negative regulation of the INK4 family member, cyclin-dependent kinase inhibitor 2C (CDKN2C), and the CIP/KIP family member, cyclin-dependent kinase inhibitor 1A (CDKN1A). These effects were antagonized by pharmacological inhibition of CDKN2C and CDKN1A targets CDK2 and CDK4 in vitro. In contrast to BRAF ( V600E ) or NRAS ( G12D )-expressing melanocytes, melanoma cells have an inherent resistance to suppression of AP-1 activity by BRAF(V600E)- or MEK-inhibitors. Here, CDK2/4 inhibition statistically significantly augmented the effects of BRAF(V600E)- or MEK-inhibitors on melanoma cell viability in vitro and growth in athymic nude Foxn1 ( nu ) mice (P = .03 when mean tumor volume at day 13 was compared for BRAF(V600E) inhibitor vs BRAF(V600E) inhibitor plus CDK2/4 inhibition; P = .02 when mean tumor volume was compared for MEK inhibitor vs MEK inhibitor plus CDK2/4 inhibition; P values were calculated by a two-sided Welch t test; n = 4-8 mice per group).

Summary Despite recent insights into melanoma genetics, systematic surveys for driver mutations are challenged by an abundance of passenger mutations caused by carcinogenic UV light exposure. We developed a permutation-based framework to address this challenge, employing mutation data from intronic sequences to control for passenger mutational load on a per gene basis. Analysis of large-scale melanoma exome data by this approach discovered six novel melanoma genes ( PPP6C , RAC1 , SNX31 , TACC1 , STK19 , and ARID2 ), three of which— RAC1 , PPP6C , and STK19 —harbored recurrent and potentially targetable mutations. Integration with chromosomal copy number data contextualized the landscape of driver mutations, providing oncogenic insights in BRAF- and NRAS-driven melanoma as well as those without known NRAS / BRAF mutations. The landscape also clarified a mutational basis for RB and p53 pathway deregulation in this malignancy. Finally, the spectrum of driver mutations provided unequivocal genomic evidence for a direct mutagenic role of UV light in melanoma pathogenesis.

To evaluate the efficacy and safety of vindesine in patients with metastatic melanoma after complete metastasectomy. One hundred and forty-two patients with metastatic spread to regional sites, lymph nodes, and distant sites after complete metastasectomy were randomized to receive either treatment with vindesine for 2 years or observation alone. Vindesine 3 mg/m intravenously was administered biweekly for the first 26 weeks following 3-week intervals for an additional 26 weeks and thereafter every 4 weeks for 52 weeks. One hundred and thirty-nine patients were eligible for intent-to-treat analysis. Median follow-up time was 46 months. Median recurrence free survival was 7.9 months in the vindesine group and 7.6 months in the observational group (P=0.40). Three-year overall survival rate was 54.9% (37 patients) for patients receiving vindesine in comparison to 43.6% (31 patients) in the observation arm (P=0.07). No grade IV toxicity was observed. The two major side effects in the vindesine group were alopecia and peripheral neuropathy. Ten patients went off treatment because of grade III toxicity. Adjuvant treatment with vindesine did not significantly prolong disease free or overall survival in high-risk melanoma patients. Thus, this randomized trial did not confirm earlier reports of beneficial effects of adjuvant vindesine and can therefore not be recommended.

Metastasis is the deadliest phase of cancer progression. Experimental models using immunodeficient mice have been used to gain insights into the mechanisms of metastasis. We report here the identification of a “metastasis aggressiveness gene expression signature” derived using human melanoma cells selected based on their metastatic potentials in a xenotransplant metastasis model. Comparison with expression data from human melanoma patients shows that this metastasis gene signature correlates with the aggressiveness of melanoma metastases in human patients. Many genes encoding secreted and membrane proteins are included in the signature, suggesting the importance of tumor-microenvironment interactions during metastasis. (Mol Cancer Res 2008;6(5):760–9)

If untreated at early stages, melanoma becomes a highly aggressive cancer with rapid metastasis to distant sites. Although cell biologic analyses have uncovered a multitude of signaling pathways involved in melanoma genesis and progression – including the MAPK, PI3K, and FAK pathways – efficacious therapies that target these cellular components have remained elusive. Genome-wide technologies such as microarray chips and array comparative genomic hybridization have generated genetic information that can identify cellular mechanisms critical for the induction and maintainence of the malignant phenotype. Thus, such data can guide the choice of a biologically relevant drug. However, these techniques have also identified melanoma as a genetically and biologically highly heterogeneous disease that likely requires individually tailored therapies based on the patient¹s individual genetic and biologic alterations. In addition, these techniques have generated a large body of data on candidate melanoma genes that await extensive functional validation to separate so called “driver” from “passenger” events. In this review, we cover several advances in melanoma therapeutics and their current limitations as well as emerging genomic, proteomic, and epigenetic strategies for the identification of critical cellular dependencies that may be tractable to therapeutic targeting.

Chromosome region maintenance 1-mediated nucleocytoplasmic transport has been shown as a potential anticancer target in various malignancies. However, the role of the most characterized chromosome region maintenance 1 cofactor ran binding protein 3 (RanBP3) in cancer cell biology has never been investigated. Utilizing a loss-of-function experimental setting in a vast collection of genetically varied melanoma cell lines, we observed the requirement of RanBP3 in melanoma cell proliferation and survival. Mechanistically, we suggest the reinstatement of transforming growth factor-β (TGF-β)-Smad2/3-p21 Cip1 tumor-suppressor axis as part of the RanBP3 silencing-associated antiproliferative program. Employing extensive nuclear export sequence analyses and immunofluorescence-based protein localization studies, we further present evidence suggesting the requirement of RanBP3 function for the nuclear exit of the weak nuclear export sequence-harboring extracellular signal-regulated kinase protein, although it is dispensable for general CRM1-mediated nuclear export of strong nuclear export sequence-harboring cargoes. Rendering mechanistic support to RanBP3 silencing-mediated apoptosis, consequent to extracellular signal-regulated kinase nuclear entrapment, we observed increased levels of cytoplasmically restricted nonphosphorylated/active proapoptotic Bcl-2-antagonist of cell death (BAD) protein. Last, we present evidence suggesting the frequently activated mitogen-activated protein kinase signaling in melanoma as a potential founding basis for a deregulated post-translational control of RanBP3 activity. Collectively, the presented data suggest RanBP3 as a potential target for therapeutic intervention in human melanoma.

Background Despite significant advances in organ preservation, surgical techniques and perioperative care, primary graft dysfunction is a serious medical problem in transplantation medicine in general and a specific problem in patients undergoing lung transplantation. As a result, patients develop lung edema, causing reduced tissue oxygenation capacity, reduced lung compliance and increased requirements for mechanical ventilatory support. Yet, there is no effective strategy available to protect the grafted organ from stress reactions induced by ischemia/reperfusion and by the surgical procedure itself. Methods We assessed the effect of a cingulin-derived peptide, XIB13 or a random peptide in an established rat model of allogeneic lung transplantation. Donor lungs and recipients received therapeutic peptide at the time of transplantation and outcome was analyzed 100min and 28 days post grafting. Results XIB13 improved blood oxygenation and reduced vascular leak 100min post grafting. Even after 28 days, lung edema was significantly reduced by XIB13 and lungs had reduced fibrotic or necrotic zones. Moreover, the induction of an allogeneic T cell response was delayed indicating a reduced antigen exchange between the donor and the host. Conclusions In summary, we provide a new tool to strengthen endothelial barrier function thereby improving outcomes in lung transplantation.

Systematic analyses of cancer genomes promise to unveil patterns of genetic alterations linked to the genesis and spread of human cancers. High-density single-nucleotide polymorphism (SNP) arrays enable detailed and genome-wide identification of both loss-of-heterozygosity events and copy-number alterations in cancer. Here, by integrating SNP array-based genetic maps with gene expression signatures derived from NCI60 cell lines, we identified the melanocyte master regulator MITF (microphthalmia-associated transcription factor) as the target of a novel melanoma amplification. We found that MITF amplification was more prevalent in metastatic disease and correlated with decreased overall patient survival. BRAF mutation and p16 inactivation accompanied MITF amplification in melanoma cell lines. Ectopic MITF expression in conjunction with the BRAF(V600E) mutant transformed primary human melanocytes, and thus MITF can function as a melanoma oncogene. Reduction of MITF activity sensitizes melanoma cells to chemotherapeutic agents. Targeting MITF in combination with BRAF or cyclin-dependent kinase inhibitors may offer a rational therapeutic avenue into melanoma, a highly chemotherapy-resistant neoplasm. Together, these data suggest that MITF represents a distinct class of 'lineage survival' or 'lineage addiction' oncogenes required for both tissue-specific cancer development and tumour progression.

DNA vaccines can induce impressive specific cellular immune response (IR) when taking advantage of their recognition as pathogen-associated molecular patterns (PAMP) through Toll-like receptors (TLR) expressed on/in cells of the innate immune system. Among the many types of PAMP, immunostimulatory DNA, so-called CpG motifs, was shown to interact specifically with TLR9, which is expressed in plasmacytoid dendritic cells (pDC), a key regulatory cell for the activation of innate and adaptive IR. We now report that CpG motifs, when introduced into the backbone, are a useful adjuvant for plasmid-based DNA (pDNA) vaccines to induce melanoma antigen-specific protective T cell responses in the Cloudman M3/DBA/2 model. The CpG-enriched pDNA vaccine induced protection against subsequent challenge with melanoma cells at significantly higher levels than its parental unmodified vector. Preferential induction of an antigen-specific, protective T cell response could be demonstrated by (i) induction of antigen-dependent tumor cell protection, (ii) complete loss of protection by in vivo CD4+/CD8+T cell- but not NK cell-depletion, and (iii) the detection of antigen-specific T cell responses but not of relevant NK cell activity in vitro. These results demonstrate that employing PAMP in pDNA vaccines improves the induction of protective, antigen-specific, T cell-mediated IR.

In the last 2 years, it has become apparent that the p53-family members p53 and p73 play fundamentally different roles in human malignancies. In contrast to p53, many studies on cancer patients failed to detect mutational inactivation of p73 and reported overexpression of wild-type p73 instead. A possible explanation was provided by the recent discovery of N-terminal truncated isoforms of p73 (DeltaTA-p73) that act as dominant-negative inhibitors of wild-type p53 and TA-p73 and result in tumor growth in nude mice. We investigated the role of DeltaTA-p73 in the development and progression of human melanomas, which lack p53 mutations. We analyzed 8 benign melanocytic nevi, 8 primary melanomas and 19 melanoma metastases for alterations of TA-p73 and DeltaTA-p73 expression using isoform-specific real-time RT-PCR. Based on our results, p73Deltaex2 and Deltaex2/3 spliced transcripts derived from the first promoter were significantly up-regulated in melanoma metastases, whereas DeltaN-p73 generated from the second promoter was the predominant isoform in benign nevi. Moreover, increased expression of p73Deltaex2 and p73Deltaex2/3 correlated with high-levels of both TA-p73 and E2F1. Our data suggest a potential function of DeltaTA-p73 splice isoforms in melanoma progression.

Spontaneous regression of primary melanoma lesions is regarded as the result of the recognition of melanoma-associated antigen (MAA)-derived peptides by cytotoxic T-lymphocytes and destruction of melanoma cells. The transporter associated with antigen processing (TAP1/2) is likely to play a crucial role in this process since it loads antigen peptides onto MHC class I molecules. To determine the impact of TAP defects on the spontaneous regression of melanoma lesions, we have compared the expression of TAP1 and TAP2 in 39 primary melanoma lesions exhibiting clinical and histological signs of tumour regression and in 35 primary melanoma lesions without regression phenomena. TAP1 expression was significantly associated with regression of melanoma lesions, since the staining pattern with anti-TAP1 antibody was positive in 38 of the 39 lesions exhibiting regression phenomena and in only 24 of the 35 lesions without histopathological signs of tumour regression. In the latter group, six lesions were stained with a heterogeneous pattern and five with a negative pattern. Furthermore, in lesions with a heterogeneous staining pattern, a clear association was found between TAP1 expression in melanoma cells and the presence of tumour-infiltrating lymphocytes. These results suggest that TAP1 plays an important role in the MAA-specific cytotoxic T-lymphocyte response, which has been suggested to underlie the spontaneous regression of primary melanoma.

Molecular oxygen plays a central role in the pathogenesis and therapy of chronic wounds. When reactive oxygen species are overproduced, oxidative stress results, with detrimental cytotoxic effects causing delayed wound healing. Therefore, elimination of reactive oxygen species could be an important strategy to improve healing of chronic wounds. Currently first therapeutic strategies targeting reactive oxygen species by antioxidants are being introduced into the treatment of chronic wounds.

Malignant melanoma of the uvea is remarkable for purely haematogenous dissemination and its tendency to metastasise to the liver. Although the liver is involved in up to 95% of patients, 50% of these also develop extrahepatic metastases, most often in the lungs, bone, skin, and brain. The only effective treatments reported to date relied on hepatic arterial chemoembolisation or -perfusion. The objective of this study was to establish a therapy protocol addressing patients with both sole liver involvement and systemic disease. Forty-eight patients with metastatic ocular melanoma received fotemustine 100 mg m−2 either as 60-min infusion into the hepatic artery or as 15-min infusion via a peripheral vein, depending on the metastatic sites involved, i.e., restriction to the liver or hepatic together with extrahepatic disease. For the first treatment cycle this infusion was repeated after one week. For all cycles, subsequent to a three week resting period, patients received an immunotherapy consisting of subcutaneous interleukin 2 and interferon α2. Although objective responses were more frequent within the cohort receiving intraarterial fotemustine (21.7 vs 8%), this difference did not translate into a significant benefit in overall survival, i.e., 369 and 349 days, respectively. Of note, this overall survival is much longer than that repeatedly reported for stage IV uveal melanoma not treated with fotemustine, suggesting a therapeutic activity of this cytostatic drug even after systemic administration. British Journal of Cancer (2002) 87, 840–845. doi:10.1038/sj.bjc.6600521 www.bjcancer.com © 2002 Cancer Research UK

Die Kontaminationen mit Methicillin-resistentem Staphylococcus aureus stellen ein zunehmendes Problem in der Behandlung von Wunden dar. Fur die Therapie stehen insbesondere bei der ambulanten Versorgung der Patienten kaum suffiziente Optionen zur Verfugung. Wir berichten uber die erfolgreiche ambulante Therapie eines mit Methicillin-resistentem Staphylococcus aureus kontaminierten chronischen Ulkus durch Biochirurgie mit Fliegenmaden der Gattung Lucilia sericata. Die von Lucilia sericata sezernierten Proteasen des Verdauungssekretes fuhren zu einer effizienten selektiven Nekrolyse in chronischen Ulzera, sezerniertes Phenylacetat und Phenylacetataldehyd haben ebenso wie die direkte Lysierung von Mikroorganismen im Rahmen der Nahrungsaufnahme antibakterielle Eigenschaften. Diese als Biochirurgie bezeichnete Therapieoption stellt eine kostengunstige Alternative in der Behandlung chronischer Wunden dar, insbesondere dann, wenn diese mit Methicillin-resistentem Staphylococcus aureus kontaminiert sind. Aufgrund der noch geringen Akzeptanz bei Patienten und medizinischem Personal wird sie allerdings bislang nur selten eingesetzt.

International audience; Melanoma, the deadliest form of skin cancer, is highly immunogenic and frequently infiltrated with immune cells including B cells. The role of tumor-infiltrating B cells (TIBCs) in melanoma is as yet unresolved, possibly due to technical challenges in obtaining TIBCs in sufficient quantity for extensive studies and due to the limited life span of B cells in vitro. A comprehensive workflow has thus been developed for successful isolation and proteomic analysis of a low number of TIBCs from fresh, human melanoma tissue. In addition, we generated in vitro-proliferating TIBC cultures using simultaneous stimulation with Epstein-Barr virus (EBV) and the TLR9 ligand CpG-oligodesoxynucleotide (CpG ODN). The FASP method and iTRAQ labeling were utilized to obtain a comparative, semiquantitative proteome to assess EBV-induced changes in TIBCs. By using as few as 100 000 B cells ( approximately 5 mug protein)/sample for our proteomic study, a total number of 6507 proteins were identified. EBV-induced changes in TIBCs are similar to those already reported for peripheral B cells and largely involve changes in cell cycle proliferation, apoptosis, and interferon response, while most of the proteins were not significantly altered. This study provides an essential, further step toward detailed characterization of TIBCs including functional in vitro analysis.

International audience; The microphthalmia-associated transcription factor (MITF) is indispensable for the viability of melanocytic cells, is an oncogene in melanoma and has a cell type-specific expression pattern. As the modulation of MITF activity by direct chemical targeting remains a challenge, we assessed a panel of drugs for their ability to downregulate MITF expression or activity by targeting its upstream modulators. We found that the multi-kinase inhibitors midostaurin and sunitinib downregulate MITF protein levels. To identify the target molecules shared by both the drugs in melanocytic cells, a chemical proteomic approach was applied and AMP-activated kinase (AMPK) was identified as the relevant target for the observed phenotype. RNA interference and chemical inhibition of AMPK led to a decrease in MITF protein levels. Reduction of MITF protein levels was the result of proteasomal degradation, which was preceded by enhanced phosphorylation of MITF mediated by ERK. As expected, downregulation of MITF protein levels by AMPK inhibition was associated with decreased viability. Together, these results identify AMPK as an important regulator for the maintenance of MITF protein levels in melanocytic cells.

Chromosome 9p21 is frequently deleted in malignant melanoma, and one familial malignant melanoma gene has been linked to 9p21-22. Recently, the cyclin D-dependent kinase inhibitors (CDKIs) p16INK4a and p15INK4b have been localized within chromosome 9p21, and the presence of p16INK4a point mutations has been demonstrated in familial melanoma and melanoma cell lines in vitro. To analyse the role of these CDKIs in sporadic human cutaneous non-metastatic malignant melanoma, we examined 36 primary tumour specimens representing different stages of melanoma progression and their corresponding normal skin samples for the three mechanisms of CDKI inactivation described so far. Homozygous codeletion of the p16INK4a and the p15INK4b gene was detected by Southern blot analysis in two tumour samples. By direct sequencing of polymerase chain reaction (PCR)-amplified microdissected genomic DNA; no somatic or germline p16INK4a point mutations or small deletions were detected in the remaining 34 tumour samples; one individual exhibited the previously described germline codon 148 (Ala-->Thr) polymorphism. In these tumour specimens, comparative semiquantitative reverse PCR analysis of p16INK4a transcript levels revealed no evidence for repression of p16INK4a gene transcription and thus for p16INK4a promoter inactivation by DNA methylation. These results indicate homozygous p16INK4a and p15INK4b loss to occur in a subset of cutaneous melanomas and suggest, in view of the frequent loss of heterozygosity on chromosome 9p21, the presence of another tumour suppressor gene within this chromosomal region.

In cancers with a highly altered genome, distinct genetic alterations drive subsets rather than the majority of individual tumours. Here we use a sequential search across human tumour samples for transcript outlier data points with associated gene copy number variations that correlate with patient's survival to identify genes with pro-invasive functionality. Employing loss and gain of function approaches in vitro and in vivo, we show that one such gene, MTSS1, promotes the ability of melanocytic cells to metastasize and engages actin dynamics via Rho-GTPases and cofilin in this process. Indeed, high MTSS1 expression defines a subgroup of primary melanomas with unfavourable prognosis. These data underscore the biological, clinical and potential therapeutic implications of molecular subsets within genetically complex cancers.

Several melanoma cell subpopulations with tumor-initiating and/or tumor-maintaining properties exist that may contribute to chemoresistance and tumor recurrence after standard therapies. One of these subpopulations expresses a B-cell marker, CD20. In a small pilot trial, we showed that a subset of Stage IV melanoma patients may potentially benefit from an adjuvant treatment using the anti-CD20 antibody rituximab.

The performance of two proteomic sample preparation methods, "pseudoshotgun" (PSG) and filter-aided sample preparation (FASP) were compared in terms of the number of identified proteins, representation of cellular component GO (gene ontology) categories in the obtained list of proteins, and the efficiency of both methods in the proteomic analysis of a very low number of cells. Both methods were combined to obtain a proteomic profile of a short-term culture (passage 3) of melanoma cells, established in our laboratory from a human metastatic melanoma lesion. The data revealed that with FASP, usually more proteins are identified than with PSG when analyzing a higher number of cells (≥ 5000/injection), whereas PSG is favorable when analyzing only a very small amount of cells (250-500/injection). PSG and FASP, however, are complementary techniques, as combining both methods further increases the number of identified proteins. Moreover, we show that it is feasible to identify a substantial number of proteins from only 250 cells/injection that is equivalent to 60 ng of protein.

MITF (microphthalmia-associated transcription factor) is a frequently amplified lineage-specific oncogene in human melanoma, whose role in intrinsic drug resistance has not been systematically investigated. Utilizing chemical inhibitors for major signaling pathways/cellular processes, we witness MITF as an elicitor of intrinsic drug resistance. To search kinase(s) targets able to bypass MITF-conferred drug resistance, we employed a multi-kinase inhibitor-directed chemical proteomics-based differential affinity screen in human melanocytes carrying ectopic MITF overexpression. A subsequent methodical interrogation informed mitotic Ser/Thr kinase Aurora Kinase A (AURKA) as a crucial regulator of melanoma cell proliferation and migration, independent of the underlying molecular alterations, including TP53 functional status and MITF levels. Crucially, assessing the efficacy of investigational AURKA inhibitor MLN8237, we pre-emptively witness the procurement of a molecular program consistent with acquired drug resistance. This involved induction of multiple MAPK (mitogen-activated protein kinase) signaling pathway components and their downstream proliferation effectors (Cyclin D1 and c-JUN) and apoptotic regulators (MITF and Bcl-2). A concomitant AURKA/BRAF and AURKA/MEK targeting overcame MAPK signaling activation-associated resistance signature in BRAF- and NRAS-mutated melanomas, respectively, and elicited heightened anti-proliferative activity and apoptotic cell death. These findings reveal a previously unreported MAPK signaling-mediated mechanism of immediate resistance to AURKA inhibitors. These findings could bear significant implications for the application and the success of anti-AURKA approaches that have already entered phase-II clinical trials for human melanoma.

Development of multiple drug resistance mechanisms in melanomas necessitates the identification of new drug targets, which when inhibited could impact multiple cellular pathways, thus circumventing potential resistance. By performing complementary DNA microarray analysis, we identified four key components of the nucleocytoplasmic transport machinery-CRM1, RAN (RAN-GTPase), RANGAP1, and RANBP1-to be overexpressed in human melanoma metastases. Chromosome region maintenance 1 (CRM1) inhibition induced a marked depletion of prosurvival/cytoplasmic extracellular signal-regulated kinase 1/2 (Erk1/2) and p90 ribosomal S6 kinase1 and elicited persistent Erk-signaling hyperactivation. Consistently, CRM1 inhibition inflicted extensive apoptosis in melanoma cells while sparing nontransformed melanocytes and primary lung fibroblasts. Apoptosis required both the intrinsic and extrinsic apoptotic pathways and was associated with a nuclear entrapment and downregulation of the antiapoptotic CRM1 target protein, Survivin. Apoptosis was preceded by a G1 cell-cycle arrest, and even though CRM1 inhibition mediated marked p53 and p21 induction in wild-type p53 melanoma cells, the latter's silencing or inactivation failed to alleviate apoptosis. Notably, CRM1 inhibition induced cell line-specific, G1 to S progression-retarding changes in the expression of multiple cell-cycle regulatory proteins, thus potentially explaining p53 dispensability. We propose CRM1 as a potential therapeutic target in human melanoma, whose inhibition induces loss of prosurvival/cytoplasmic Erk1/2, mediates persistent Erk hyperactivation, and initiates a multitude of cell context-dependent molecular events to trigger G1 arrest followed by massive apoptosis.

Melanomas contain distinct cell subpopulations. Several of these subpopulations, including one expressing CD20, may harbor stem cell-like or tumor-initiating characteristics. We hypothesized that patients at high risk of disease recurrence could benefit from an adjuvant anti-CD20 therapy. Therefore, we initiated a small pilot trial to study the effect of the anti-CD20 antibody rituximab in a group of melanoma patients with stage IV metastatic disease who had been rendered without evident disease by way of surgery, chemotherapy and/or radiation therapy. The major objective was safety, while secondary objectives were description of recurrence-free intervals (RFI) and overall survival (OS). Nine patients received rituximab at 375 mg/m(2) qw for 4 weeks followed by a maintenance therapy every 8 weeks. Treatment was discontinued after 2 years or with disease recurrence. Treatment was well tolerated. After a median observation of 42 months, the median neither of RFI nor of OS has been reached. Despite therapy that ended after 2 years, six out of nine patients are still alive and five of them are recurrence-free. Though the patient number is too small for definitive conclusions, our data may represent a first example of the potential therapeutic value of targeting CD20(+) cell populations-at least for a subset of patients.