Suzanne Egyhazi Brage

Melanoma-educated CD14+ cells acquire a myeloid-derived suppressor cell phenotype through COX-2-dependent mechanisms.

Tumors can suppress the host immune system by employing a variety of cellular immune modulators, such as regulatory T cells, tumor-associated macrophages, and myeloid-derived suppressor cells (MDSC). In the peripheral blood of patients with advanced stage melanoma, there is an accumulation of CD14(+)HLA-DR(lo/-) MDSC that suppress autologous T cells ex vivo in a STAT-3-dependent manner. However, a precise mechanistic basis underlying this effect is unclear, particularly with regard to whether the MDSC induction mechanism relies on cell-cell contact of melanoma cells with CD14(+) cells. Here, we show that early-passage human melanoma cells induce phenotypic changes in CD14(+) monocytes, leading them to resemble MDSCs characterized in patients with advanced stage melanoma. These MDSC-like cells potently suppress autologous T-cell proliferation and IFN-γ production. Notably, induction of myeloid-suppressive functions requires contact or close proximity between monocytes and tumor cells. Further, this induction is largely dependent on production of cyclooxygenase-2 (COX-2) because its inhibition in these MDSC-like cells limits their ability to suppress T-cell function. We confirmed our findings with CD14(+) cells isolated from patients with advanced stage melanoma, which inhibited autologous T cells in a manner relying up prostaglandin E2 (PGE2), STAT-3, and superoxide. Indeed, PGE2 was sufficient to confer to monocytes the ability to suppress proliferation and IFN-γ production by autologous T cells ex vivo. In summary, our results reveal how immune suppression by MDSC can be initiated in the tumor microenvironment of human melanoma.

Laminins 411 and 421 differentially promote tumor cell migration via α6β1 integrin and MCAM (CD146).

α4-laminins, such as laminins 411 and 421, are mesenchymal laminins expressed by blood and lymphatic vessels and some tumor cells. Laminin-411 promotes migration of leukocytes and endothelial cells, but the effect of this laminin and laminin-421 on tumor cells is poorly understood. In the present study, we demonstrate that laminin-411 and, to a greater extent, laminin-421 significantly promote migration of tumor cells originated from melanomas, gliomas and different carcinomas via α6β1 integrin. In solid-phase binding assays, both laminins similarly bound α6β1 integrin but only laminin-421, among several laminin isoforms, readily bound MCAM (CD146), a cell-surface adhesion molecule strongly associated with tumor progression. Accordingly, a function-blocking mAb to MCAM inhibited tumor cell migration on laminin-421 but not on laminins 411 or 521. In tumor tissues, melanoma cells co-expressed MCAM, laminin α4, β1, β2 and γ1 chains, and integrin α6 and β1 chains. The present data highlight the novel role of α4-laminins in tumor cell migration and identify laminin-421 as a primary ligand for MCAM and a putative mediator of tumor invasion and metastasis.

High expression of glycolytic and pigment proteins is associated with worse clinical outcome in stage III melanoma.

There are insufficient numbers of prognostic factors available for prediction of clinical outcome in patients with stage III malignant cutaneous melanoma, even when known adverse pathological risk factors, such as macrometastasis, number of lymph node metastases, and ulceration are taken into consideration. The aim of this study was therefore to identify additional prognostic factors to better predict patients with a high risk of relapse, thus enabling us to better determine the need for adjuvant treatment in stage III disease. An RNA oligonucleotide microarray study was performed on first regional lymph node metastases in 42 patients with stage III melanoma: 23 patients with short-term survival (⩽13 months) and 19 with long-term survival (≥60 months), to identify genes associated with clinical outcome. Candidate genes were validated by real-time PCR and immunohistochemical analysis. Several gene ontology (GO) categories were highly significantly differentially expressed including glycolysis (GO: 0006096; P<0.001) and the pigment biosynthetic process (GO: 0046148; P<0.001), in which overexpression was associated with short-disease-specific survival. Three overexpressed glycolytic genes, GAPDHS, GAPDH, and PKM2, and two pigment-related genes, TYRP1 and OCA2, were selected for validation. A significant difference in GAPDHS protein expression between short- and long-term survivors (P=0.021) and a trend for PKM2 (P=0.093) was observed in univariate analysis. Positive expression of at least two of four proteins (GAPDHS, GAPDH, PKM2, TYRP1) in immunohistochemical analysis was found to be an independent adverse prognostic factor for disease-specific survival (P=0.011). Our results indicate that this prognostic panel in combination with established risk factors may contribute to an improved prediction of patients with a high risk of relapse.

Transcriptional profiling of breast cancer metastases identifies liver metastasis-selective genes associated with adverse outcome in luminal A primary breast cancer

Purpose: The complete molecular basis of the organ-specificity of metastasis is elusive. This study aimed to provide an independent characterization of the transcriptional landscape of breast cancer metastases with the specific objective to identify liver metastasis–selective genes of prognostic importance following primary tumor diagnosis. Experimental Design: A cohort of 304 women with advanced breast cancer was studied. Associations between the site of recurrence and clinicopathologic features were investigated. Fine-needle aspirates of metastases (n = 91) were subjected to whole-genome transcriptional profiling. Liver metastasis–selective genes were identified by significance analysis of microarray (SAM) analyses and independently validated in external datasets. Finally, the prognostic relevance of the liver metastasis–selective genes in primary breast cancer was tested. Results: Liver relapse was associated with estrogen receptor (ER) expression (P = 0.002), luminal B subtype (P = 0.01), and was prognostic for an inferior postrelapse survival (P = 0.01). The major variation in the transcriptional landscape of metastases was also associated with ER expression and molecular subtype. However, liver metastases displayed unique transcriptional fingerprints, characterized by downregulation of extracellular matrix (i.e., stromal) genes. Importantly, we identified a 17-gene liver metastasis–selective signature, which was significantly and independently prognostic for shorter relapse-free (P < 0.001) and overall (P = 0.001) survival in ER-positive tumors. Remarkably, this signature remained independently prognostic for shorter relapse-free survival (P = 0.001) among luminal A tumors. Conclusions: Extracellular matrix (stromal) genes can be used to partition breast cancer by site of relapse and may be used to further refine prognostication in ER positive primary breast cancer. Clin Cancer Res; 22(1); 146–57. ©2015 AACR.

Metabolic markers and HSP60 in chemonaive serous solid ovarian cancer versus ascites.

Objective Metabolic pathway alterations in cancer are thought to be dependent upon tumor type–specific oncogenic activation and local nutrient and oxygen supply during disease progression. In serous ovarian cancer, the typical peritoneal spread of disease is caused by shedding of tumor cells into the abdominal cavity, often along with ascites formation. Not much is known about the metabolic features of these detached serous tumor cells. In this study, we investigate the messenger RNA (mRNA) expression of GAPDH (glycolytic glyceraldehyde 3-phosphate dehydrogenase) and PKM2 (pyruvate kinase isoform M2), ATP5B (mitochondrial β-F1-ATPase), and heat shock protein 60 in matched serous solid tumor and corresponding ascites. Materials/Methods Fresh samples from solid tumor and corresponding ascites were prospectively collected from 40 patients undergoing primary surgery for suspected advanced ovarian cancer. Of these, 25 met the study eligibility criteria, that is, stage IIC to IV disease of the serous (24) or endometrioid (1) subtype with solid and ascites specimens containing 50% or more tumor cells and with good quality and quantity mRNA yield. All but 2 patients (92%) had type II disease. GAPDH, PKM2, ATP5B, and HSP60 mRNA expressions were assessed by real-time polymerase chain reaction. For each marker, the mRNA expression in solid tumor was pairwise compared with the corresponding expression in ascites using the Wilcoxon matched pairs signed rank sum test. Results In contrast to our hypothesis, the mRNA expression of analyzed metabolic markers and HSP60 did not significantly differ between matched solid tumor and malignant ascites. Conclusions Our results indicate that further expression changes in genes related to glycolysis or oxidative phosphorylation are not a prerequisite for serous cancer cell survival after detachment.

ΔNp73 regulates the expression of the multidrug-resistance genes ABCB1 and ABCB5 in breast cancer and melanoma cells - a short report

PurposeMultidrug resistance (MDR) is a major cause of treatment failure. In cancer cells, MDR is often caused by an increased efflux of therapeutic drugs mediated by an up-regulation of ATP binding cassette (ABC) transporters. It has previously been shown that oncogenic ΔNp73 plays an important role in chemo-resistance. Here we aimed at unraveling the role of ΔNp73 in regulating multidrug resistance in breast cancer and melanoma cells.MethodsKEGG pathway analysis was used to identify pathways enriched in breast cancer samples with a high ΔNp73 expression. We found that the ABC transporter pathway was most enriched. The expression of selected ABC transporters was analyzed using qRT-PCR upon siRNA/shRNA-mediated knockdown or exogenous overexpression of ΔNp73 in the breast cancer-derived cell lines MCF7 and MDA-MB-231, as well as in primary melanoma samples and in the melanoma-derived cell line SK-MEL-28. The ability to efflux doxorubicin and the concomitant effects on cell proliferation were assessed using flow cytometry and WST-1 assays.ResultsWe found that high ΔNp73 levels correlate with a general up-regulation of ABC transporters in breast cancer samples. In addition, we found that exogenous expression of ΔNp73 led to an increase in the expression of ABCB1 and ABCB5 in the breast cancer-derived cell lines tested, while knocking down of ΔNp73 resulted in a reduction in ABCB1 and ABCB5 expression. In addition, we found that ΔNp73 reduction leads to an intracellular retention of doxorubicin in MDA-MB-231 and MCF7 cells and a concomitant decrease in cell proliferation. The effect of ΔNp73 on ABCB5 expression was further confirmed in metastases from melanoma patients and in the melanoma-derived cell line SK-MEL-28.ConclusionsOur data support a role for ΔNp73 in the multidrug-resistance of breast cancer and melanoma cells.

Silencing FLI or targeting CD13/ANPEP lead to dephosphorylation of EPHA2, a mediator of BRAF inhibitor resistance, and induce growth arrest or apoptosis in melanoma cells

A majority of patients with BRAF-mutated metastatic melanoma respond to therapy with BRAF inhibitors (BRAFi), but relapses are common owing to acquired resistance. To unravel BRAFi resistance mechanisms we have performed gene expression and mass spectrometry based proteome profiling of the sensitive parental A375 BRAF V600E-mutated human melanoma cell line and of daughter cell lines with induced BRAFi resistance. Increased expression of two novel resistance candidates, aminopeptidase-N (CD13/ANPEP) and ETS transcription factor FLI1 was observed in the BRAFi-resistant daughter cell lines. In addition, increased levels of the previously reported resistance mediators, receptor tyrosine kinase ephrine receptor A2 (EPHA2) and the hepatocyte growth factor receptor MET were also identified. The expression of these proteins was assessed in matched tumor samples from melanoma patients obtained before BRAFi and after disease progression. MET was overexpressed in all progression samples while the expression of the other candidates varied between the individual patients. Targeting CD13/ANPEP by a blocking antibody induced apoptosis in both parental A375- and BRAFi-resistant daughter cells as well as in melanoma cells with intrinsic BRAFi resistance and led to dephosphorylation of EPHA2 on S897, previously demonstrated to cause inhibition of the migratory capacity. AKT and RSK, both reported to induce EPHA2 S897 phosphorylation, were also dephosphorylated after inhibition of CD13/ANPEP. FLI1 silencing also caused decreases in EPHA2 S897 phosphorylation and in total MET protein expression. In addition, silencing of FLI1 sensitized the resistant cells to BRAFi. Furthermore, we show that BRAFi in combination with the multi kinase inhibitor dasatinib can abrogate BRAFi resistance and decrease both EPHA2 S897 phosphorylation and total FLI1 protein expression. This is the first report presenting CD13/ANPEP and FLI1 as important mediators of resistance to BRAF inhibition with potential as drug targets in BRAFi refractory melanoma.

Abstract B28: PTENpg1 antisense RNA mediates PTEN suppression in vemurafenib resistance and predicts clinical outcome in melanoma patients

Approximately 50% of cutaneous melanomas carry activating mutations in the serine/threonine protein kinase BRAF. Vemurafenib is a highly potent inhibitor of BRAFV600E and prolongs survival in ~80% of melanoma patients carrying the mutation. Unfortunately, almost all patients develop resistance within 6-8 months of starting treatment. The molecular mechanism explaining this scenario is largely unclear, but loss of PTEN expression, has been suggested. In this study we reveal a role for the PTEN pseudogene encoded antisense RNA (PTENpg1 asRNA) in epigenetic suppression of PTEN in melanoma cell lines resistant to vemurafenib. Resistant cell lines showed increased PTENpg1 asRNA expression while PTEN expression was suppressed. ChIP analysis showed enrichment of the histone modification enzyme EZH2 and subsequent enrichment of H3K27me3 at the PTEN promoter in the resistant cell line. Total cellular levels of EZH2, DNMT3a and H3k27me3 were, however, unaffected thus indicating specific recruitment of these factors to the PTEN promoter in the resistant cells by a mechanism that is dictated by the increased expression of PTENpg1 asRNA. In addition, we show that PTEN is reactivated by the depletion of EZH2 and DNMT3a and that this reactivation of PTEN re-sensitizes the cells to vemurafenib treatment. Finally, we show that PTENpg1 asRNA could be a promising prognostic marker of clinical outcome of melanoma patients. PTENpg1 asRNA expression levels were measured in samples from patients that had not received any oncological treatment and were classified with stage III melanomas. We found that high PTENpg1 asRNA expression correlates with short-term survival in melanoma patients. In conclusions, the PTENpg1 asRNA appears to be an important player in vemurafenib resistance and could be an attractive therapeutic target. In addition, PTENpg1 asRNA is potentially a promising prognostic marker for clinical outcome for melanoma patients. Citation Format: Linda Vidarsdottir, Alireza Azimi, Jason Serviss, Christian Ingvar, Goran Jonsson, Hakan Olsson, Marianne Frostvik Stolt, Johan Hansson, Suzanne Egyhazi Brage, Dan Grander, Per Johnsson. PTENpg1 antisense RNA mediates PTEN suppression in vemurafenib resistance and predicts clinical outcome in melanoma patients. [abstract]. In: Proceedings of the AACR Special Conference on Noncoding RNAs and Cancer: Mechanisms to Medicines ; 2015 Dec 4-7; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2016;76(6 Suppl):Abstract nr B28.