Human Melanoma Progression Research Articles

IL-36γ Transforms the Tumor Microenvironment and Promotes Type 1 Lymphocyte-Mediated Antitumor Immune Responses

Cytokines play a pivotal role in regulating tumor immunogenicity and antitumor immunity. IL-36γ is important for the IL-23/IL-17-dominated inflammation and anti-BCG Th1 immune responses. However, the impact of IL-36γ on tumor immunity is unknown. Here we found that IL-36γ stimulated CD8(+) Tcells, NK cells, and γδ Tcells synergistically with TCR signaling and/or IL-12. Importantly, IL-36γ exerted profound antitumor effects invivo and transformed the tumor microenvironment in favor of tumor eradication. Furthermore, IL-36γ strongly increased the efficacy of tumor vaccination. Moreover, IL-36γ expression inversely correlated with the progression of human melanoma and lung cancer. Our study establishes a role of IL-36γ in promoting antitumor immune responses and suggests its potential clinical translation into cancer immunotherapy.

The importance of microenvironment: the role of CCL8 in metastasis formation of melanoma.

We have attempted to characterize the changes occurring on the host side during the progression of human melanoma. To investigate the role of tumor microenvironment, we set up such an animal model, which was able to isolate the host related factors playing central role in metastasis formation. One of these 'factors', CCL12, was consequently selected and its behavior was examined alongside its human homologue (CCL8). In our animal model, metastasis forming primary melanoma in the host exhibited increased level of CCL12 mRNA expression. In clinical samples, when examining the tumor and the host together, the cumulative (tumor and host) CCL8 expression was lower in the group in which human primary melanoma formed lung metastasis compared to non-metastatic primary tumors. We could not detect significant difference in CCL8 receptor (CCR1) expression between the two groups. Increased migration of the examined tumor cell lines was observed when CCL8 was applied as a chemoattractant. The tumor cells and their interactions can be influenced the expression of CCL8 by dermal fibroblasts, as a significant change in the metastatic microenvironment. Furthermore, we examined changes in miRNA profile resulted by CCL8 and miR146a appears to be a promising prognostic marker for following this process.

Prognostic significance of ALCAM (CD166/MEMD) expression in cutaneous melanoma patients.

BackgroundALCAM (activated leukocyte cell adhesion molecule, CD166, MEMD) is a transmembrane protein of immunoglobulin superfamily (Ig-SF) and plays an important role in human malignant melanoma progression and formation of locoregional and distant metastases. The study using melanoma cell lines showed that overexpression of ALCAM is directly related with the increase of cytoaggregation and the ability to form cell nests. The aim of the study was to assess the expression and intracellular localization of ALCAM in primary skin melanomas and metastatic lesions from regional lymph nodes. Also, prognostic significance of ALCAM expression in primary tumor cells and metastatic lesion cells was evaluated in the context of 5-year observation.MethodsFormalin-fixed paraffin-embedded tissue specimens from 104 primary cutaneous melanomas and 16 regional lymph nodes metastases were studied for the expression of ALCAM measured by immunohistochemistry.ResultsWe demonstrate that high ALCAM expression in primary melanoma cells (IRS ≥8) is strongly correlated with unfavorable prognosis as compared with patients with lower ALCAM immunoreactivity in tumor compartment as regards cancer specific overall survival (CSOS) (P = 0.001) and disease free survival (DFS) (P < 0.001). Additionally lower ALCAM immunoreactivity in nodal metastatic foci was significantly statistically correlated with deeper melanoma invasion in the primary tumor according to Clark scale (P = 0.032). It was also found that decreased ALCAM expression (IRS <8) in nodal metastases shows a trend related with a correlation with shorter cancer specific overall survival (P = 0.083). Statistically significant correlations were also demonstrated between the presence of ulceration and decreased intensity of lymphocytic inflammatory infiltration and a high percentage of ALCAM-positive cells (P = 0.035, P = 0.01, respectively).ConclusionsHigh ALCAM expression in melanoma cells of the primary tumor can be used as a marker of negative outcome and may indicate a more invasive phenotype of cancer cells, which would require a more intensive therapeutic strategy. Low expression of ALCAM in regional lymph node metastases is a feature associated with unfavorable prognosis in patients with cutaneous melanoma. Our study is the first one to evaluate the effect of increased ALCAM expression on long-term survival in melanoma patients.

PP69 - Hydrogen sulfide as an endogenous “controller” of human melanoma progression

PP69 - Hydrogen sulfide as an endogenous “controller” of human melanoma progression

The multifaceted role of CD146/MCAM in the promotion of melanoma progression.

Human malignant melanoma is a common primary malignant cutaneous tumour derived from transformed epidermal melanocytes. Patients with melanoma have a high rate of mortality due to resistance to chemotherapeutic drugs, a major obstacle to a successful treatment. Several reports have suggested that CD146 plays an important role as a signalling molecule in human melanoma. This role includes CD146 as a participant in inflammation, differentiation, adhesion, tumourigenicity, metastasis, invasion and angiogenesis among other processes, which suggests that this molecule promotes the progression of human melanoma as a multifaceted regulator. In this article, we explore the effects and corresponding mechanisms with respect to the role of CD146/MUC18 in the promotion of human melanoma progression. Collectively, the studies indicated that targeting CD146, because it is a suitable marker of poor patient outcome, might be useful in the design of future strategies for the prevention and treatment of human melanoma.

Analysis of microRNA-203 function in CREB/MITF/RAB27a pathway: comparison between canine and human melanoma cells.

MicroRNA (miR)-203 is downregulated and acts as an anti-oncomir in melanoma cells. Here, using human and canine melanoma cells, we elucidated the effects of miR-203 on cyclic adenosine monophosphate response element binding protein (CREB)/microphthalmia-associated transcription factor (MITF)/RAB27a pathway, which is known to be important for the development and progression of human melanoma. In this study, we showed that miR-203 directly targeted CREB1 and regulated its downstream targets, MITF and RAB27a. miR-203 significantly suppressed the growth of human and canine melanoma cells and inhibited melanosome transport through the suppression of the signalling pathway. In conclusion, miR-203 was shown to be a common tumour-suppressive miRNA in human and canine melanoma and thus to play a crucial role in the biological mechanisms of melanoma development.

Abstract 4200: Interaction between mPGES-1 and iNOS promotes human melanoma progression

Abstract Melanoma cells in vivo are well known to express varying inflammatory features, which is not limited by somatic mutational subclass. Among the most prevalent of inflammatory markers are iNOS (inducible Nitric Oxide Synthase) generated NO production and COX-2/PGE2, and for which their active pathways have been shown to enhance carcinogenesis and tumor progression, stimulate angiogenesis, support tumor growth, and promote metastasis. COX-2 inhibitors are well studied agents that inhibit tumor growth and prevent tumor development including melanoma, but the focus of research has shifted to develop inhibitors for enzymes, which are downstream of COX-2, especially microsomal PGE2 synthase-1 (mPGES-1), due to the cardiovascular risk associated with the initial COX-2 inhibitory drugs. Here, we demonstrate crosstalk between iNOS/NO and mPGES-1/PGE2 signaling pathways and suggest that mPGES-1 is a novel potential therapeutic target in human melanoma employing a spectrum of well-defined human cell lines, as well as human tissues. Our melanoma stage III survival Tissue MicroArray analysis shows that the expression of mPGES-1 is elevated in 65% of human stage III melanomas and intense expression of mPGES-1 is significantly associated with the short-term survival of patients. More interestingly, about 90 % of patient samples which express mPGES-1 were also positive for iNOS. In addition, treatment of human melanoma cells with NO donors or constitutively-driven expression of iNOS resulted in increased PGE2 production, which was suppressed by mPGES-1 inhibition, indicating that the pathway is active and targetable. Moreover, iNOS was found to interact directly with mPGES-1, and iNOS or NO donors enhance mPGES-1 activity in melanoma cells and in vitro, suggesting that iNOS-mediated NO promotes PGE2 production through mPGES-1 activation. mPGES-1 inhibition by its shRNA or specific inhibitors suppressed human melanoma cell viability and migration. Collectively, these findings suggest that the interaction between iNOS and mPGES-1 is associated with human melanoma progression and could be considered as a novel target for translational application in melanoma growth regulation. Citation Format: Sun-Hee Kim, Yuuri Hashimoto, Suhendan Ekmekcioglu, Elizabeth A. Grimm. Interaction between mPGES-1 and iNOS promotes human melanoma progression. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4200. doi:10.1158/1538-7445.AM2014-4200

Epigenetics of human melanoma: promises and challenges.

Melanoma is the deadliest form of skin cancer with rising incidence and mortality rates. Although early-stage melanoma is highly curable, advanced-stage melanoma is refractory to treatment. This underscores the importance of prevention and early detection as well as the need to improve treatment and prognostication of human melanoma. Elucidating the underlying mechanisms of the initiation and progression of human melanoma can help identify potential targets of intervention for prevention, diagnosis, therapy, and prognosis of this disease. Aberrant DNA methylation and histone modifications are the best-established epigenetic mechanisms of carcinogenesis. The occurrence of epigenetic changes prior to clinical diagnosis of cancer and their reversibility through pharmacologic/genetic approaches offer a promising avenue for basic and translational research on human melanoma. Candidate gene(s) or genome-wide aberrant DNA methylation and histone modifications have been observed in human melanoma tumor tissues and cell lines, and correlated to cellular and functional characteristics and/or clinicopathological features of this malignancy. The present review summarizes the published researches on aberrant DNA methylation and histone modifications in connection with human melanoma. Representative studies are highlighted to set forth the current state of knowledge, gaps in the knowledgebase, and future directions in these epigenetic fields of research. Examples of epigenetic therapy applied for human melanoma in vitro, and the challenges of its in vivo application for clinical treatment of solid tumors are discussed.

Combination Immunotherapy of Melanoma by inhibiting HSP90 and targeting its client proteins. (TUM7P.934)

Abstract HSP90 plays a major role in human melanoma progression, by facilitating the over expression of its client proteins, many of which provide growth, survival and migratory advantages to tumor cells and support a pro-angiogenic tumor microenvironment. HSP90-mediated stabilization also limits the proteasome-dependent processing of client proteins and the subsequent presentation of derivative peptides in tumor cell-associated MHC class I complexes which is required for effective host CD8+ T cell recognition of melanoma cells. When considered in the combination of active vaccination, inhibiting HSP90 function might serve as a highly effective anti-tumor therapy. As a consequence, we analyzed the anti-tumor impact of a range of clinically-relevant HSP90 inhibitors (HSP90i; i.e. NVP-AUY922, STA9090, 17-DMAG, Novobiocin) on client protein expression in vitro (human and murine melanoma cell lines) and in vivo (s.c. B16 tumors established in syngenic C57BL/6 mice). We observed that HSP90i promote the proteasome-dependent (i.e. blocked by inhibitors PS-341 and MG-132) degradation of a range of client proteins. We have also identified H-2Kb/Db-presented peptide epitopes derived from these client proteins that may be recognized by Type-1 CD8+ T cells after specific vaccination. We are currently investigating the capacity of NVP-AUY922 and STA9090 to therapeutically sensitize established melanomas to client protein-specific CD8+ T cells in combination therapy approaches.

Signal Transduction in Human Cutaneous Melanoma and Target Drugs

Malignant melanoma is an extremely aggressive and metastatic cancer, highly resistant to conventional treatment modalities. Understanding of fundamental mechanisms responsible for its genesis and progression is critical for development of successful chemotherapeutic treatment. It is becoming clear that melanoma results from complex changes in multiple signaling pathways that control cell proliferation and ability to evade the cell death processes. Impairment or hyper-activation of some components of these pathways may lead to malignant transformation and cancer development. In the present review we consider the current data on involvement of such signaling pathways as cyclin/CDK, Ras/Raf/MEK/MAPK, JNK/c-Jun/AP-1, PI3K/Akt/PTEN/mTOR, IKK/I-κB/NF-κB, Wnt/β-catenin, Notch, Jak/STAT, MITF and some growth factors in regulation of the cell cycle progression, apoptosis and development of human cutaneous melanoma. Understanding of molecular aberrations that underlie melanoma oncogenesis is essential for improvement of diagnosis, accurate prognosis assessment, and rational design of effective therapeutics. Inhibitors of these pathways may serve as promising tools for anti-melanoma targeted therapy. Some novel anti-melanoma target drugs are characterized.

Expression of the RNase III enzyme DROSHA is reduced during progression of human cutaneous melanoma

Aberrant expression of microRNAs (miRNAs) and their biogenesis factors has been frequently observed in different types of cancer. We recently reported that expression of DICER1 is reduced in metastatic melanoma. Nevertheless, so far very little is known about the expression pattern of other miRNA biogenesis factors in this type of malignancy. Here, we investigated the expression pattern of DROSHA in a large set of melanocytic lesions (n=409) by tissue microarray and immunohistochemistry. We found that nuclear expression of DROSHA is markedly reduced in the early stages of melanoma progression (P=0.0001) and is inversely correlated with melanoma thickness (P=0.0001), AJCC stages (P=0.0001), and ulceration status (P=0.002). We also confirmed the reduced expression of nuclear DROSHA by a second specific antibody raised against a different region of the DROSHA protein. In addition, we observed that the reduced nuclear expression of DROSHA during melanoma progression is accompanied by an increased cytoplasmic expression of this protein (P=0.0001). Finally, we found that expression pattern of DROSHA varies from that of DICER1 and concomitant loss of expression of both DICER1 and DROSHA confers the worse outcome for melanoma patients. Our results demonstrate a reduced nuclear expression of DROSHA, which further highlights a perturbed miRNA biogenesis pathway in melanoma. In addition, the aberrant subcellular localization of DROSHA indicates possible deregulation in the mechanisms responsible for its proper localization in the nucleus.

Raf kinase inhibitor protein (RKIP) and phospho-RKIP expression in melanomas

Melanoma, a cancer notorious for its high potential to metastasize, arises from melanocytes, cells dedicated to melanin production and located in the basal layer of the epidermis. Raf-1 kinase inhibitor protein (RKIP) is an inhibitory molecule that down-regulates the effects of the Ras/Raf/MEK/ERK signaling pathway. The aim of this study was to examine the expression of RKIP and pRKIP in melanomas at different stages. We evaluated the RKIP and pRKIP protein by immunohistochemistry in control skin, pigmented nevi and melanomas, and through Western blotting in human normal melanocytes and in four different melanoma-derived cell lines (WM35, A375, M14, and A2058). Our results demonstrated a correlation between the expression of RKIP and pRKIP, and metastatic ability in melanoma cells. This raises the possibility to analyze both RKIP and pRKIP in all melanomas. Down-regulation of both RKIP and pRKIP expression could represent a useful marker of metastatic melanoma. On the contrary for non-metastatic melanoma, especially in Clark I and II, low RKIP and high pRKIP expression could be indicative. In conclusion, the observed negative correlation of the RKIP and pRKIP expression in metastatic melanomas indicates that expression of these proteins may become a prognostic marker for the progression of human cutaneous melanoma. We propose that the investigation of both RKIP and pRKIP may provide a useful tool indicative for metastatic or non-metastatic melanoma in different Clark's level melanomas. Further studies are required to verify the molecular background of the observed RKIP and pRKIP variations.

Abstract 2709: Functional Role of FKBP51 in malignant progression of melanoma.

Abstract FKBP51 is a high molecular weight FK506-binding protein involved in the regulation of diverse biological processes. Its aberrant expression and pathological implications has been reported in some cancer types; however, its role in malignant melanoma has remained underexplored. In this study, we investigated the functional role of FKBP51 in melanoma pathogenesis by performing in vitro and in vivo studies. FKBP51 expression was observed in majority of primary and derivative melanoma cell lines. Interestingly, a greater expression of FKBP51 was detected in metastatic derivative lines (A375SM and FEMX-I) as compared to their respective parental cells (A375P and FEMX-V). Next, we stably repressed the expression of FKBP51 in A375SM and FEMX-I cells through short-hairpin RNA (shRNA)-mediated silencing. FKBP51 repression led to a decrease in growth and clonogenicity, in part, through suppression of cell cycle progression and induction of apoptosis. A reduced motility and invasion was also observed in both the FKBP51-silenced melanoma cell lines. Immunoblot analyses demonstrated loss of mesenchymal markers and elevated expression of epithelial markers in FKBP51-silenced cells, indicating a role of FKBP51 in epithelial to mesenchymal transition of melanoma cells. When injected subcutaneously into nude mice, FKBP51-silenced A375SM cells displayed significant inhibition of tumor growth as compared to the control cells. Immunohistochemical analysis of tumor tissues demonstrated a decrease in the proliferating (Ki67 positive) cells and increased numbers of apoptotic (TUNEL positive) cells in FKBP51-silenced A375SM as compared with control tumors. Furthermore, low vessel density and infiltration of myeloid derived suppressor cells (MDSC) was observed in tumors formed by FKBP51-silenced cells as examined by isolectin lectin B4 (Griffonia simplicifolia isolectin B4) and Gr-1 staining, respectively. Notably, tail vein injection of FKBP51- silenced cells produced no metastatic lesions in lungs, while significant metastases was observed in lungs of mice injected with control cells. Estimation of interleukin-8 (IL-8/CXCL-8), a chemokine previously associated with melanoma growth, metastasis and angiogenesis, demonstrated its decreased production in FKBP51-silenced cells and derived tumors. In conclusion, our study provides experimental evidence to support the functional significance of FKBP51 in malignant progression of human melanoma. Citation Format: Gurpreet Kaur, Sanjeev K. Srivastava, Sumit Arora, Arun Bhardwaj, Steven McClellan, Jonathan G. Scammell, William E. Grizzle, Laurie B. Owen, Oystein Fodstad, Ajay P. Singh, Seema Singh. Functional Role of FKBP51 in malignant progression of melanoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2709. doi:10.1158/1538-7445.AM2013-2709

Abstract C9: Human melanoma metastasis in NSG mice correlates with clinical outcome in patients

Abstract Although metastasis is the leading cause of cancer-related deaths, little is known about the molecular mechanisms that enable tumor cells to metastasize. We have recently developed a model in which for the first time human melanomas readily engraft in nonobese diabetic/severe combined immunodeficient interleukin-2 receptor-g chain null (NSG) mice. Melanomas from 25 patients exhibit reproducible differences in the rate of spontaneous metastasis after transplantation into NSG mice. Importantly metastasis in mice is strongly correlated with metastasis, and clinical outcome, in the patients, providing an opportunity to test the mechanisms of metastatic progression of human melanoma in an animal model. In transplanted mice, efficiently metastasizing melanomas have much higher levels of circulating melanoma cells compared to inefficiently metastasizing ones, suggesting that the rate of entry into the blood is one factor that limits the rate of metastasis. In addition, we have profiled both genomic mutations and gene expression in 33 primary human melanomas with varying metastatic potential, in order to gain insight into the key regulatory pathways involved in melanoma metastasis. Using our xenograft model we are currently investigating the role of select genes in enhancing melanoma metastasis, at the level of intravasation into the blood stream, survival in circulation and proliferation in distal organs. Citation Format: Elena Piskounova, Elsa Quintana, Mark Shackleton, Timothy M. Johnson, Sean J. Morrison. Human melanoma metastasis in NSG mice correlates with clinical outcome in patients. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr C9.

Demonstration of a Melanoma-Specific CD44 Alternative Splicing Pattern That Remains Qualitatively Stable, but Shows Quantitative Changes during Tumour Progression

The role of CD44 in the progression of human melanoma has mostly been characterised by qualitative changes in expression of its individual variable exons. These exons however, may be expressed to form a number of molecules, the alternative splice variants of CD44, which may be structurally and functionally different. Using real-time PCR measurements with variable exon specific primers we have determined that all are expressed in human melanoma. To permit comparison between different tumours we identified a stable CD44 variable exon (CD44v) expression pattern, or CD44 ‘fingerprint’. This was found to remain unchanged in melanoma cell lines cultured in different matrix environments. To evaluate evolution of this fingerprint during tumour progression we established a scid mouse model, in which the pure expression pattern of metastatic primary tumours, circulating cells and metastases, non-metastatic primary tumours and lung colonies could be studied. Our analyses demonstrated, that although the melanoma CD44 fingerprint is qualitatively stable, quantitative changes are observed suggesting a possible role in tumour progression.

Clonal dominance of CD133+ subset population as risk factor in tumor progression and disease recurrence of human cutaneous melanoma

Chemotherapeutic refractoriness of advanced cutaneous melanoma may be linked with melanoma-initiating cells, also known as melanoma stem cells. This study aimed to determine relative risk of clonal dominance of the CD133+ phenotype in tissues from melanoma patients with different clinical outcomes that could be applied to early diagnosis, prognosis or disease monitoring. Significant overexpression of CD133 (p<0.02) was observed by immunohistochemical staining in tissues from patients with recurrent disease versus those without disease recurrence. Relative risk analysis between these two groups suggested that the patients with recurrence or metastatic lesion had a greater than 2-fold overexpression of CD133. In addition, immunodetectable CD133 corroborated with upregulation of CD133 RNA levels (14- to 30-fold) as assessed by quantitative real-time reverse transcription-PCR (qRT-PCR) comparison of melanoma cell lines derived from patients with poor clinical outcomes and short overall survival (<10 months), vs. those derived from patients with good clinical outcomes and longer overall survival (>24 months). Further, cells derived from patients, and MACS-sorted according to their CD133 status retained their CD133-positivity (>95%) or CD133-negativity (>95%) for more than 8 passages in culture. CD133+ cells could repopulate and form tumors (p<0.03) in athymic NCr-nu/nu mice within 8 weeks while no tumors were observed with CD133− phenotype (up to 200,000 cells). Taken together, the study demonstrates, for the first time, that there exists a clonal dominance of a CD133+ population within the hierarchy of cells in cutaneous tissues from patients that have undergone successive progressive stages of melanoma, from primary to metastatic lesions. CD133, thus, provides a predictive marker of disease as well as a potential therapeutic target of high-risk melanoma.

Development of a tridimensional microvascularized human skin substitute to study melanoma biology

Cutaneous malignant melanomas represent an important clinical problem because they are highly invasive, they can metastasize to distant sites and are typically resistant to available therapy. The precise molecular determinants responsible for melanoma progression and chemo-resistance are not yet known, in part due to lack of pertinent experimental models that mimic human melanoma progression. Accordingly, we developed a complex human microvascularized reconstructed skin substitute in which the organized three-dimensional (3D) architecture of the native skin is reproduced. Human melanoma cell lines derived from primary and metastatic sites were added to this 3D model. Our results demonstrate that histological features and behavior of melanoma cells applied in our skin substitute model are specific to their site of origin. In particular, the ability of melanoma cells to cross the dermal-epidermal junction correlates with their metastatic potential. In addition, a potent angiogenic effect was detected for an aggressive metastatic cell line that produces VEGF. The presence of a microvascular network within this model will allow studying a crucial step of the metastatic process. We conclude that such an in vitro human tumor microvascularized reconstructed skin substitute promises to be a versatile and efficient model to investigate skin cancer progression and to screen new anticancer drugs to improve currents clinical treatments.

SOX2 modulates levels of MITF in normal human melanocytes, and melanoma lines in vitro

SOX2 modulates levels of MITF in normal human melanocytes, and melanoma lines in vitro

CCL27–CCR10 and CXCL12–CXCR4 chemokine ligand-receptor mRNA expression ratio: new predictive factors of tumor progression in cutaneous malignant melanoma

CXCR4, CCR7 and CCR10 chemokine receptors are known to be involved in melanoma metastasis. Our goal was to compare the relative intratumoral mRNA expression of these receptors with that of their corresponding chemokine ligands, CXCL12, CCL19, CCL21, and CCL27 across the full spectrum of human melanoma progression: thin and thick primary melanomas, as well as "in transit", lymph node, and distant metastases. Expression was quantified by real-time RT-PCR in 103 melanoma samples: 51 primary tumors and 52 metastases. Particular emphasis was focused on chemokine ligand-receptor expression ratios. Immunohistochemistry was performed to identify the cell types expressing these molecules. CXCL12-CXCR4 and CCL27-CCR10 ratios were higher in thin than in thick primary melanomas, and all four chemokine-receptor ratios were higher in primary tumors than in melanoma metastases. CCL27-CCR10 and CXCL12-CXCR4 expression ratios in primary tumors were inversely associated with the development of distant metastases, and improved the predictive value of tumor thickness for distant metastasis, which is important since chemokine ligand-receptor ratios are not affected by the endogenous gene employed for normalizing mRNA expression. Both receptor and ligand immunolabeling were detected in neoplastic cells suggesting autocrine mechanisms. Our results support the concept that low CCL27/CCR10 and CXCL12/CXCR4 intratumoral mRNA ratios are associated with melanoma progression, and in combination with Breslow thickness, are the best predictive factors for the development of distant metastases in primary cutaneous melanoma.

Abstract 2106: Long non-coding RNA signatures for melanoma detection in humans

Abstract Melanoma, an aggressive carcinoma that originates in the basal layer of human epidermis, has the highest mortality rate of skin cancers in industrialized countries. Unfortunately, current treatments for metastatic melanoma provide mostly palliative benefits to only a small proportion of patients. Despite the obvious need for improvement in assessment and treatment of metastatic melanoma, the intricate mechanisms underlying melanoma transformation remain unresolved and poorly understood. Thus, there is considerable interest in understanding the molecular basis of initiation and progression of human melanomas. Recent evidence indicates that long non-coding RNAs (lncRNAs), a subclass of noncoding RNA (ncRNA), are associated with carcinogenesis in melanoma as well as several other human cancers. The elucidation of the molecular function of these RNA species promises to bridge gaps in our knowledge of melanoma development in humans. The expression of selected lncRNAs (CR618740 and AF091731) in a panel of melanoma cell lines (pigmented and non-pigmented), melanocytes, and keratinocytes were assayed by DNA microarray (Ncode arrays from Lifetechnologies) and further confirmed by real-time polymerase chain reaction (qRT-PCR). Next, cell lines results were tested with patient samples. Our results indicate that the differential expression of lncRNAs is an indicator of the development of melanoma, and dysregulated expression of these markers may be involved in the transition of melanocytes to melanoma. Furthermore, the presence of significant correlation between melanoma cell line characteristics (stage, cell phenotype, types of mutations and others) and lncRNA expression data may imply novel causal connection between lncRNA expression and melanoma development. Importantly, this work will investigate the new possibility that lncRNAs play an essential role in cellular regulation and represent a potential platform for melanoma progression. Thus, unraveling the differential lncRNA expression in melanoma could initiate novel understanding of melanocyte homeostasis, tissue organization, and melanoma genesis in humans. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2106. doi:1538-7445.AM2012-2106