Melanoma inhibitory activity in melanoma diagnostics and therapy - a small protein is looming large

Characterization and analysis of extracellular vesicle-derived miRNAs from different adipose tissues in mice

Adipose tissue is traditionally classified into two main types based on their functions: brown adipose tissue (BAT) and white adipose tissue (WAT). Each type plays a distinct role in the body's energy metabolism. Additionally, a third type, beige adipose tissue, can develop within subcutaneous WAT (including inguinal WAT, iWAT) in response to specific stimuli and exhibits characteristics of both BAT and WAT. Extracellular vesicles (EVs) are crucial for intercellular communication, carrying a diverse array of biomolecules such as proteins, lipids, and nucleic acids. While the functional diversity and endocrine roles of adipose tissues are well-documented, a comparative analysis of the functions of EVs released by different adipose tissues from mice housed at room temperature has not been thoroughly explored. MicroRNAs (miRNAs), which are highly enriched in small extracellular vesicles (sEVs), offer a promising avenue for investigating the complex functions and unique roles of various adipose tissues. In this study, we isolated sEVs from different adipose tissues under basal conditions and performed a comprehensive analysis of their miRNA content. By comparing miRNA profiles across different adipose tissues, we aim to elucidate the potential roles of sEV-derived miRNAs in mediating intercellular communication and the distinct physiological functions of adipose tissues. Understanding the molecular features of miRNAs in adipose tissue EVs could reveal new aspects of adipose tissue biology and lay the groundwork for further research into their physiological significance.

Bioluminescent aptamer-based microassay for detection of melanoma inhibitory activity protein (MIA)

Melanoma inhibitory activity protein (MIA) does obviously offer the potential to reveal clinical manifestations of melanoma. Despite a pressing need for effective diagnosis of this highly fatal disease, there are no clinically approved MIA detection ELISA kits available. A recommended MIA threshold has not yet been defined, mostly by reason of variability in immunoglobulins' affinity and stability, the difference in sample preparation and assay conditions. Here we present a pair of high-affinity DNA aptamers developed as an alternative recognition and binding element for MIA detection. Their stability and reproducible synthesis are expected to ensure this analysis under standard conditions. The devised aptamer-based solid-phase microassay of model standard and control human sera involves luciferase NLuc as a highly sensitive reporter. Bioluminescence dependence on MIA concentration ranges in a linear manner from 2.5 to 250 ng mL-1, providing a MIA detection limit of 1.67 ± 0.57 ng mL-1.

Biosensors for melanoma skin cancer diagnostics

Skin cancer is a critical global public health concern, with melanoma being the deadliest variant, correlated to 80% of skin cancer-related deaths and a remarkable propensity to metastasize. Despite notable progress in skin cancer prevention and diagnosis, the limitations of existing methods accentuate the demand for precise diagnostic tools. Biosensors have emerged as valuable clinical tools, enabling rapid and reliable point-of-care (POC) testing of skin cancer. This review offers insights into skin cancer development, highlights essential cutaneous melanoma biomarkers, and assesses the current landscape of biosensing technologies for diagnosis. The comprehensive analysis in this review underscores the transformative potential of biosensors in revolutionizing melanoma skin cancer diagnosis, emphasizing their critical role in advancing patient outcomes and healthcare efficiency. The increasing availability of these approaches supports direct diagnosis and aims to reduce the reliance on biopsies, enhancing POC diagnosis. Recent advancements in biosensors for skin cancer diagnosis hold great promise, with their integration into healthcare expected to enhance early detection accuracy and reliability, thereby mitigating socioeconomic disparities.

Increased Peripheral Blood DNA Damage and Elevated Serum Levels of Melanoma Inhibitory Activity Protein: Clues to Excess Skin Cancer Risk in Airline Pilots?

Background and objective The risk of malignant melanoma (MM) and other forms of skin cancer appears to be higher in airline pilots (APs), potentially due to their exposure to ionizing and ultraviolet (UV) radiation. We explored the possibility of increased peripheral blood DNA damage and elevated serum levels of the melanoma inhibitory activity (MIA) protein - a serological marker for MM known to be stimulated by UV radiation - in this professional group. Methods This was a case-control study involving 40 male APs, each of whom was age- and tenure-matched (≥5 years of service) with 40 male office workers (OWs). We assessed DNA damage in the two professional groups by performing comet and micronucleus (MN) assays on peripheral blood. Serum levels of MIA protein were quantified using an immunoassay. Results The comet tail lengths and the frequency of MN were significantly higher in APs (4.57 ± 0.79 µm and 2.05 ± 0.26 per 1000 cells, respectively) than in OWs (3.81 ± 0.60 µm and 1.76 ± 0.31 per 1000 cells, respectively, both p<0.001). Furthermore, serum MIA levels were also significantly higher in APs (7.45 ± 0.95 ng/mL) than in OWs (5.78 ± 0.54 ng/mL, p<0.001). A significant positive correlation was found between comet tail lengths in APs and their serum MIA concentrations (r=0.68, p<0.01). Conclusions The increased burden of DNA damage and elevated serum MIA levels in APs may offer an explanation for their higher susceptibility to MM and other types of skin cancers.

Correlation Studies between S100 Protein Level and Soluble MIA or Tissue MelanA and gp100 (HMB45) Expression in Cutaneous Melanoma

(1) Background: Cutaneous melanoma (CM) originates from melanocytes and causes 90% of skin cancer deaths; therefore, the comparison of different soluble and tissue markers could be valuable in the detection of melanoma progression and therapy monitoring. The present study is focused on the potential correlations between soluble S100B and MIA protein levels in different melanoma stages or with tissue expression of S100, gp100 (HMB45), and MelanA biomarkers. (2) Methods: Soluble S100B and MIA levels were evaluated by means of immunoassay methods in blood samples from 176 patients with CM, while tissue expressions of S100, MelanA, and gp100 (HMB45) were detected by means of immunohistochemistry in 76 melanomas. (3) Results: Soluble S100B correlated with MIA in stages III (r = 0.677, p < 0.001) and IV (r = 0.662, p < 0.001) but not in stages I and II; however, 22.22% and 31.98% of stage I and II patients, respectively, had high values for at least one of the two soluble markers. S100 tissue expression correlated with both MelanA (r = 0.610, p < 0.001) and HMB45 (r = 0.476, p < 0.01), while HMB45 and MelanA also significantly positively correlated (r = 0.623, p < 0.001). (4) Conclusions: Blood levels of S100B and MIA corroborated with melanoma tissue markers expression could help to improve the stratification process for patients with a high risk of tumor progression.

Deviating Alternative Splicing as a Molecular Subtype of Microsatellite Stable Colorectal Cancer

PURPOSE

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. Biomarkers to aid in prognostication and treatment decisions are in high demand, and to facilitate their development, a better understanding of the underlying biology of the highly heterogeneous disease is needed.

METHODS

A genome-scale alternative splicing (AS) analysis using RNA-sequencing data from primary microsatellite stable (MSS) CRCs from 127 patients was performed. Splice variant-specific expression levels of individual cancer samples were compared with the total set of samples, and a metric for a tumor sample's global amount of deviating AS was developed. This metric varied considerably across the cohort and ranged from 6 to 282 deviating AS events per tumor sample. A threshold of 45 or more deviating events was set to distinguish cancers with high (n = 44) and low (n = 83) levels of deviating AS.

RESULTS

Patients with high amounts of AS deviations had significantly shorter time to relapse compared with patients with fewer deviations (P = .04). Furthermore, differential gene expression analysis revealed nine known cancer-critical genes that are significantly upregulated in samples with high amounts of deviating AS. Validation of the results in an independent cohort of MSS CRCs showed the same tendency toward shorter progression-free survival among the high-deviation group. In both cohorts, enrichment for growth factors was identified among upregulated genes associated with this phenotype.

CONCLUSION

There is a large variation in the amount of deviating AS among MSS CRCs, and we provide evidence that those with high amounts of deviations represent different cancer biology.

Starch-Coated Magnetic Iron Oxide Nanoparticles for Affinity Purification of Recombinant Proteins

Starch-coated magnetic iron oxide nanoparticles have been synthesized by a simple, fast, and cost-effective co-precipitation method with cornstarch as a stabilizing agent. The structural and magnetic characteristics of the synthesized material have been studied by transmission electron microscopy, Mössbauer spectroscopy, and vibrating sample magnetometry. The nature of bonds between ferrihydrite nanoparticles and a starch shell has been examined by Fourier transform infrared spectroscopy. The data on the magnetic response of the prepared composite particles have been obtained by magnetic measurements. The determined magnetic characteristics make the synthesized material a good candidate for use in magnetic separation. Starch-coated magnetic iron oxide nanoparticles have been tested as an affinity sorbent for one-step purification of several recombinant proteins (cardiac troponin I, survivin, and melanoma inhibitory activity protein) bearing the maltose-binding protein as an auxiliary fragment. It has been shown that, due to the highly specific binding of this fragment to the starch shell, the target fusion protein is selectively immobilized on magnetic nanoparticles and eluted with the maltose solution. The excellent efficiency of column-free purification, high binding capacity of the sorbent (100–500 µg of a recombinant protein per milligram of starch-coated magnetic iron oxide nanoparticles), and reusability of the obtained material have been demonstrated.

N-extended photoprotein obelin to competitively detect small protein tumor markers

Two variants of Ca²⁺-regulated photoprotein obelin, extended from the N-terminus with small tumor markers - melanoma inhibitory activity protein (MIA) and survivin, one of the protein inhibitors of apoptosis, were designed, obtained and studied. Both domains in the obtained hybrid proteins exhibit the properties of the initial molecules: the main features of Ca²⁺-triggered bioluminescence are close to those of obelin, and the tumor markers' domains are recognized and bound by the corresponding antibodies. The obtained hybrids compete with the corresponding tumor markers for binding with antibodies, immobilized on the surface and their use has been shown to be promising as bioluminescent labels in a one-stage solid-phase competitive immunoassay.

[Epithelioid angiomyolipoma of the kidney after successfully treated malignant melanoma]

Hintergrund

Die Therapie der epitheloiden Angiomyolipome (eAML) kann eine Herausforderung darstellen, da bei dieser sehr seltenen Unterform der gutartigen mesenchymalen Angiomyolipome anders als bei den klassischen Angiomyolipomen bei bis zu 30 % der Fälle Lymphknotenmetastasen, lokale Rezidive und Fernmetastasen auftreten.

Ziel der Arbeit

Wir berichten hier nach unserer Recherche erstmals in Deutschland von einem Fall von eAML nach stattgehabtem malignem Melanom.

Material und Methoden

Neben der Klinik und Histologie wird die genetische Untersuchung des Tumorgewebes dargestellt.

Ergebnisse

Es fand sich eine somatische, trunkierende Mutation des TSC2-Gens („tuberous sclerosis complex“) im Angiomyolipom.

Schlussfolgerung

Die Beziehung zu verwandten Tumorentitäten in der histologischen Diagnostik wird dargestellt und eine mögliche Rolle der genetischen Diagnostik für die Therapieplanung diskutiert.

The value of melanoma inhibitory activity and LDH with melanoma patients in a Chinese population

ABSTRACT

Malignant melanoma is a highly malignant tumor originating from the melanocytes of the neural crest, which is prone to metastasis and has a poor prognosis. Previous research demonstrated that melanoma inhibitory activity (MIA) and lactate dehydrogenase (LDH) could serve as serum markers in malignant melanoma and indicate prognosis in the Caucasian race. Researchers suspected that both MIA and LDH could prompt the prognosis of malignant melanoma in the Chinese population. This study aimed to investigate the value of MIA and LDH in the prognosis of acral malignant melanoma.From January 1, 2014, to December 31, 2017, in Jiangsu Province, 44 acral malignant melanoma patients with complete data were chosen from the clinic. The LDH levels were extracted from their clinical data, and MIA levels were measured by enzyme-linked immunosorbent assay method. 8 paired advancing samples before and after metastasis were examined. 22 health donors were matched to the patient group. Receiver operating characteristic (ROC) curves of MIA and LDH were drawn to determine acral malignant melanoma tumorigenesis and metastasis and finally got the cut-off value. Cumulative survival was illustrated with the Kaplan-Meier plot, and factors were compared using the Log-rank test.Compared with age-matched healthy donors, MIA was significantly high in patients (P < .001). Moreover, serum MIA was significantly higher in III-IV stage patients than I-II stage patients (P < .001). However, there was no such association between LDH and melanoma stage and risk. Further study indicated that the MIA cut-off > 914.7pg/mL predicted disease progression with 86.4% specificity and 95.5% sensitivity. In the Kaplan-Meier analysis, MIA levels were independent risk factors for long-term mortality of acral malignant melanoma patients.It concluded that the quantification of MIA in the serum should be performed as a general standard of care in patients at risk of developing metastatic melanoma.

Identification of oral squamous cell carcinoma markers MUC2 and SPRR1B downstream of TANGO

PURPOSE

Transport and Golgi organization protein 1 (TANGO) promotes angiogenesis and lymphangiogenesis in oral squamous cell carcinoma (OSCC). To elucidate the underlying mechanisms, this study aims to identify and characterize elements downstream of TANGO that mediate its involvement in OSCC.

METHODS

In this study, microarray analysis compared gene expression between control and TANGO-repressed HSC3 cells. Protein expression in 213 OSCC tissue samples was analyzed immunohistochemically.

RESULTS

TANGO repression decreased or increased expression of Mucin 20 (MUC20) and small proline-rich protein 1B (SPRR1B), respectively. MUC20 increased the growth and invasiveness of OSCC cells via altered matrix metalloproteinase (MMP)-2 and E-cadherin expression and c-met phosphorylation. MUC20 induced angiogenesis and lymphangiogenesis by activating vascular endothelial growth factors A and C. In well-differentiated OSCC, SPRR1B expression was high (P = 0.0091) and correlated with keratinization markers and promoted proliferation by inducing mitogen-activated protein kinase p38 phosphorylation. MUC20 expression correlated significantly with clinical stage (P = 0.0024), lymph node metastasis (P = 0.0036), and number of blood and lymph vessels (P < 0.0001). MUC20-expressing cases had a significantly worse prognosis than non-expressing cases (P < 0.0001).

CONCLUSION

MUC20 and SPRR1B located downstream of TANGO may be useful molecular markers for OSCC.

Double venipuncture is not required for adequate S-100B determination in melanoma patients

S-100B is used in melanoma follow-up. This serum biomarker is also present in adipocytes; therefore, subcutaneous adipocytes trapped in the needle before performing a venipuncture could contaminate the serum. The aim was to study the influence of adipocyte contamination on blood samples used for S-100B analysis, possibly resulting in falsely elevated S-100B values. A total of 294 serum samples were collected from 147 American Joint Committee on Cancer staging stage III melanoma patients. The mean difference between the first (dummy) and second tubes was 0.003 μg/l (p = 0.077), with a decrease in the second tube. Compared with the second tube, the S-100B level was higher in the first tube in 33.3% of the samples, equal in 36.8% of the samples and lower in 29.9% of the samples. No significant difference between the two consecutively drawn tubes was found. There seems to be no necessity of implementing a dummy tube system for accurate S-100B determination in melanoma patients.

Cutaneous melanoma dissemination is dependent on the malignant cell properties and factors of intercellular crosstalk in the cancer microenvironment (Review)

The incidence of cutaneous malignant melanoma has been steadily increasing worldwide for several decades. This phenomenon seems to follow the trend observed in many types of malignancies caused by multiple significant factors, including ageing. Despite the progress in cutaneous malignant melanoma therapeutic options, the curability of advanced disease after metastasis represents a serious challenge for further research. In this review, we summarise data on the microenvironment of cutaneous malignant melanoma with emphasis on intercellular signalling during the disease progression. Malignant melanocytes with features of neural crest stem cells interact with non‑malignant populations within this microenvironment. We focus on representative bioactive factors regulating this intercellular crosstalk. We describe the possible key factors and signalling cascades responsible for the high complexity of the melanoma microenvironment and its premetastatic niches. Furthermore, we present the concept of melanoma early becoming a systemic disease. This systemic effect is presented as a background for the new horizons in the therapy of cutaneous melanoma.

Does the Use of the "Proseek® Multiplex Oncology I Panel" on Peritoneal Fluid Allow a Better Insight in the Pathophysiology of Endometriosis, and in Particular Deep-Infiltrating Endometriosis?

Endometriosis appears to share certain cancer-related processes, such as cell attachment, invasion, proliferation and neovascularization, some of which can also be found in other healthy tissues. In order to better understand the altered milieu of the peritoneal cavity, while acknowledging the reported similarities between endometriosis and neoplastic processes, we applied a multiplex oncology panel to search for specific biomarker signatures in the peritoneal fluid of women with endometriosis, women with deep-infiltrating endometriosis (DIE), as well as controls. In total, 84 patients were included in our study, 53 women with endometriosis and 31 controls. Ninety-two proteins were measured in prospectively collected peritoneal fluid (PF) samples, using the "Proseek® Multiplex Oncology I Panel". We first compared patients with endometriosis versus controls, and in a second step, DIE versus endometriosis patients without DIE. Out of the 92 analyzed proteins, few showed significant differences between the groups. In patients with endometriosis, ICOS ligand, Endothelial growth factor, E-selectin, Receptor tyrosine-protein kinase erbB-2, Interleukin-6 receptor alpha, Vascular endothelial growth factor receptor 2, Fms-related tyrosine kinase 3 ligand, C-X-C motif chemokine 10, Epididymal secretory protein E4 and Folate receptor-alpha were decreased, while Interleukin-6 and Interleukin-8 were increased compared to controls. Looking at patients with DIE, we found Chemokine ligand 19, Stem cell factor, Vascular endothelial growth factor D, Interleukin-6 receptor alpha and Melanoma inhibitory activity to be increased compared to endometriosis patients without DIE. We have shown a distinct regulation of the immune response, angiogenesis, cell proliferation, cell adhesion and inhibition of apoptosis in PF of patients with endometriosis compared to controls. The specific protein pattern in the PF of DIE patients provides new evidence that DIE represents a unique entity of extrauterine endometriosis with enhanced angiogenetic and pro-proliferative features.

Genome-wide Analysis of Common Copy Number Variation and Epithelial Ovarian Cancer Risk

BACKGROUND

Germline DNA copy number variation (CNV) is a ubiquitous source of genetic variation and remains largely unexplored in association with epithelial ovarian cancer (EOC) risk.

METHODS

CNV was quantified in the DNA of approximately 3,500 cases and controls genotyped with the Illumina 610k and HumanOmni2.5M arrays. We performed a genome-wide association study of common (>1%) CNV regions (CNVRs) with EOC and high-grade serous (HGSOC) risk and, using The Cancer Genome Atlas (TCGA), performed in silico analyses of tumor-gene expression.

RESULTS

Three CNVRs were associated (P < 0.01) with EOC risk: two large (∼100 kb) regions within the 610k set and one small (<5 kb) region with the higher resolution 2.5M data. Large CNVRs included a duplication at LILRA6 (OR = 2.57; P = 0.001) and a deletion at CYP2A7 (OR = 1.90; P = 0.007) that were strongly associated with HGSOC risk (OR = 3.02; P = 8.98 × 10^-5). Somatic CYP2A7 alterations correlated with EGLN2 expression in tumors (P = 2.94 × 10^-47). An intronic ERBB4/HER4 deletion was associated with reduced EOC risk (OR = 0.33; P = 9.5 × 10^-2), and somatic deletions correlated with ERBB4 downregulation (P = 7.05 × 10^-5). Five CNVRs were associated with HGSOC, including two reduced-risk deletions: one at 1p36.33 (OR = 0.28; P = 0.001) that correlated with lower CDKIIA expression in TCGA tumors (P = 2.7 × 10^-7), and another at 8p21.2 (OR = 0.52; P = 0.002) that was present somatically where it correlated with lower GNRH1 expression (P = 5.9 × 10^-5).

CONCLUSIONS

Though CNV appears to not contribute largely to EOC susceptibility, a number of low-to-common frequency variants may influence the risk of EOC and tumor-gene expression.

IMPACT

Further research on CNV and EOC susceptibility is warranted, particularly with CNVs estimated from high-density arrays.

The oxidoreductase p66Shc acts as tumor suppressor in BRAFV600E-transformed cells

Metabolic reprogramming, as exemplified by the shift from oxidative phosphorylation to glycolysis, is a common feature of transformed cells. In many tumors, altered metabolism is also reflected in increased reactive oxygen species (ROS) levels, which contribute to proliferation and survival signaling. However, despite high ROS levels, cancer cells can be efficiently killed by further increasing ROS production. We have shown previously that both wild‐type and oncogenic CRAF and BRAF prevent excessive mitochondrial ROS production. Subsequently, it has been demonstrated that raising ROS levels in BRAFV600E‐transformed melanoma cells by inhibiting BRAF or MEK rendered them susceptible to cell death induction. To understand how oncogenic BRAF affects mitochondrial ROS production in melanoma, we studied the mitochondrial ROS‐producing oxidoreductase p66Shc, which is frequently overexpressed in tumors. Using NIH 3T3 BRAFV600E fibroblasts and the melanoma cell lines A375 and M238 carrying the same BRAF mutation, we show that under treatment with the ROS‐inducing agent phenethyl isothiocyanate (PEITC), oncogenic BRAF renders cells refractory to p66ShcS36 phosphorylation, which is essential for p66Shc activation and mitochondrial ROS production. Consistent with this, the activation of JNK1/2, which phosphorylate S36, was blunted, while other mitogen‐activated protein kinases were not affected. Inhibition of JNK1/2 efficiently prevented ROS production, while BRAF and MEK inhibitors increased ROS levels. Vemurafenib‐resistant M238R melanoma cells were impaired in S36 phosphorylation and ROS production following PEITC treatment. Moreover, they failed to increase ROS levels after MEK/BRAF inhibition. Finally, shRNA‐mediated knockdown of p66Shc led to increased growth of BRAFV600E‐transformed NIH 3T3 cells in soft agar assay. Taken together, these data suggest that phosphorylation‐activated p66Shc functions as a tumor suppressor in melanoma cells.

The neurotrophin Neuritin1 (cpg15) is involved in melanoma migration, attachment independent growth, and vascular mimicry

The neurotrophin Neuritin1 (NRN1; cpg15) belongs to the candidate plasticity gene (CPG) family and is expressed in postmitotic-differentiating neurons of the developmental nervous system and neuronal structures associated with plasticity in the brain of human adult.Our newest findings document that NRN1 deregulation could contribute also to disease development and have impact on malignant melanoma. Our analyses displayed the over-expression of NRN1 in melanoma in vitro and in vivo, shown by immunohistochemistry and qRT-PCR on microdissected melanoma tissue; furthermore, soluble NRN1 was detectable in tissue culture supernatant and serum of melanoma patients.To investigate the role of NRN1 in melanoma we performed knockdown, over-expression and recombinant-NRN1-treatment experiments affiliated by functional assays. Our results show that migration, attachment independent growth and vasculogenesis were affected after manipulation of NRN1 on endogenous and extrinsic level. Interestingly, high NRN1 serum levels correlate with low MIA serum levels (< 10ng/ml). Therefore, we speculate that NRN1 could be a marker for early melanoma stages, in particular.In summary, we detected an overexpression of NRN1 in melanoma patient. In functional cell culture experiments we found a correlation between NRN1 expression and the cancerous behavior of melanoma cells.

Massively parallel nanowell-based single-cell gene expression profiling

Background

Technological advances have enabled transcriptome characterization of cell types at the single-cell level providing new biological insights. New methods that enable simple yet high-throughput single-cell expression profiling are highly desirable.

Results

Here we report a novel nanowell-based single-cell RNA sequencing system, ICELL8, which enables processing of thousands of cells per sample. The system employs a 5,184-nanowell-containing microchip to capture ~1,300 single cells and process them. Each nanowell contains preprinted oligonucleotides encoding poly-d(T), a unique well barcode, and a unique molecular identifier. The ICELL8 system uses imaging software to identify nanowells containing viable single cells and only wells with single cells are processed into sequencing libraries. Here, we report the performance and utility of ICELL8 using samples of increasing complexity from cultured cells to mouse solid tissue samples. Our assessment of the system to discriminate between mixed human and mouse cells showed that ICELL8 has a low cell multiplet rate (< 3%) and low cross-cell contamination. We characterized single-cell transcriptomes of more than a thousand cultured human and mouse cells as well as 468 mouse pancreatic islets cells. We were able to identify distinct cell types in pancreatic islets, including alpha, beta, delta and gamma cells.

Conclusions

Overall, ICELL8 provides efficient and cost-effective single-cell expression profiling of thousands of cells, allowing researchers to decipher single-cell transcriptomes within complex biological samples.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-3893-1) contains supplementary material, which is available to authorized users.

Expression Profiling of Clinical Specimens Supports the Existence of Neural Progenitor-Like Stem Cells in Basal Breast Cancers

BACKGROUND

We previously characterized in salivary adenoid cystic carcinoma (ACC) a novel population of cancer stem cells (CSCs) marked by coexpression of 2 stemness genes, sex-determining region Y (SRY)-related HMG box-containing factor 10 (SOX10) and CD133. We also reported that in ACC and basal-like breast carcinoma (BBC), a triple-negative breast cancer subtype, expression of SOX10 similarly demarcates a highly conserved gene signature enriched with neural stem cell genes. On the basis of these findings, we hypothesized that BBC might be likewise driven by SOX10-positive (SOX10⁺)/CD133⁺ cells with neural stem cell properties.

MATERIALS AND METHODS

To validate our hypothesis on clinical data, we used a novel approach to meta-analysis that merges gene expression data from independent breast cancer studies and ranks genes according to statistical significance of their coexpression with the gene of interest. Genes that showed strong association with CD133/PROM1 as well as SOX10 were validated across different platforms and data sets and analyzed for enrichment with genes involved in neurogenesis.

RESULTS

We identified in clinical breast cancer data sets a highly conserved SOX10/PROM1 gene signature that contains neural stem cell markers common for Schwann cells, ACC, BBC, and melanoma. Identification of tripartite motif-containing 2 (TRIM2), TRIM29, MPZL2, potassium calcium-activated channel subfamily N member 4 (KCNN4), and V-set domain containing T cell activation inhibitor 1 (VTCN1)/B7 homolog 4 (B7H4) within this signature provides insight into molecular mechanisms of CSC maintenance.

CONCLUSION

Our results suggest that BBC is driven by SOX10⁺/CD133⁺ cells that express neural stem cell-specific markers and share molecular similarities with CSCs of neural crest origin. Our study provides clinically relevant information on possible drivers of these cells that might facilitate development of CSC-targeting therapies against this cancer distinguished with poor prognosis and resistance to conventional therapies.

Melanoma-derived IL-1 converts vascular endothelium to a proinflammatory and procoagulatory phenotype via NFκB activation

Spreading of melanoma is associated with efficient extravasation of circulating tumor cells from the vascular system into distant target organs. This process is accompanied and supported by proinflammatory and procoagulatory conditions. In this study, we analysed the ability of human melanoma cell lines to activate endothelial cells (ECs) in vitro. Some melanoma cells, that is, MV3, were shown to trigger an prompt calcium-flux-dependent, procoagulatory endothelial response that was accompanied by luminal release of ultra-large von Willebrand factor (ULVWF) fibres that were immobilized to the endothelial surface layer. In contrast to MV3-derived supernatant, prolonged treatment of ECs with WM9-derived supernatant mediated a pronounced activation of nuclear factor kappa B (NFκB). NFκB activation in ECs was dependent on both IL-1α and IL-1β secreted from melanoma cells. Melanoma-derived IL-1 mediated an upregulation of proinflammatory cytokines IL-6 and IL-8, the intercellular adhesion molecule-1 (ICAM-1), the vascular cell adhesion molecule-1 (VCAM-1) and the procoagulatory tissue factor (TF) in ECs. Our data show that melanoma cells activate ECs either directly and within seconds or by an IL-1-mediated NFκB activation. Both pathways of EC activation convert the regular repressive function of ECs on inflammation and coagulation to a proinflammatory and procoagulatory surface that supports tumor progression.

Covalent small molecule inhibitors of Ca(2+)-bound S100B

Elevated levels of the tumor marker S100B are observed in malignant melanoma, and this EF-hand-containing protein was shown to directly bind wild-type (wt) p53 in a Ca(2+)-dependent manner, dissociate the p53 tetramer, and inhibit its tumor suppression functions. Likewise, inhibiting S100B with small interfering RNA (siRNA(S100B)) is sufficient to restore wild-type p53 levels and its downstream gene products and induce the arrest of cell growth and UV-dependent apoptosis in malignant melanoma. Therefore, it is a goal to develop S100B inhibitors (SBiXs) that inhibit the S100B-p53 complex and restore active p53 in this deadly cancer. Using a structure-activity relationship by nuclear magnetic resonance approach (SAR by NMR), three persistent binding pockets are found on S100B, termed sites 1-3. While inhibitors that simultaneously bind sites 2 and 3 are in place, no molecules that simultaneously bind all three persistent sites are available. For this purpose, Cys84 was used in this study as a potential means to bridge sites 1 and 2 because it is located in a small crevice between these two deeper pockets on the protein. Using a fluorescence polarization competition assay, several Cys84-modified S100B complexes were identified and examined further. For five such SBiX-S100B complexes, crystallographic structures confirmed their covalent binding to Cys84 near site 2 and thus present straightforward chemical biology strategies for bridging sites 1 and 3. Importantly, one such compound, SC1982, showed an S100B-dependent death response in assays with WM115 malignant melanoma cells, so it will be particularly useful for the design of SBiX molecules with improved affinity and specificity.