Genetic and Genomic Pathways of Melanoma Development, Invasion and Metastasis

Periodic magnetic modulation enhanced electrochemical analysis for highly sensitive determination of genomic DNA methylation

DNA methylation aberrations have a strong correlation with cancer in early detection, diagnosis, and prognosis, which make them possible candidate biomarkers. Electrochemical biosensors offer rapid protocols for detecting DNA methylation status with minimal pretreatment of samples. However, the inevitable presence of background current in the time domain, including electrochemical noise and variations, limits the detection performance of these biosensors, especially for low concentration analytes. Here, we propose an ultrasensitive frequency-domain electrochemical analysis strategy to effectively separate the weak signals from background current. To achieve this, we employed periodic magnetic field modulation of magnetic beads (MBs) on and off the electrode surface to generate a periodic electrochemical signal for subsequent frequency-domain analysis. By capturing labeled MBs with as low as 0.5 pg of DNA, we successfully demonstrated a highly sensitive electrochemical method for determination of genome-wide DNA methylation levels. We also validated the effectiveness of this methodology using DNA samples extracted from three types of hepatocellular carcinoma (HCC) cell lines. The results revealed varying genomic methylation levels among different HCC cell lines, indicating the potential application of this approach for early-stage cancer detection in terms of DNA methylation status.

The novel prognostic marker SPOCK2 regulates tumour progression in melanoma

Secreted protein acidic and cysteine rich/osteonectin, cwcv and kazal-like domain proteoglycan 2 (SPOCK2) is a protein that regulates cell differentiation and growth. Recent studies have reported that SPOCK2 plays important roles in the progression of various human cancers; however, the role of SPOCK2 in melanoma remains unknown. Therefore, this study investigated the roles of SPOCK2 and the related mechanisms in melanoma progression. To evaluate the clinical significance of SPOCK2 expression in patients with melanoma, we analysed the association between SPOCK2 expression and its prognostic value for patients with melanoma using systematic multiomic analysis. Subsequently, to investigate the roles of Spock2 in melanoma progression in vitro and in vivo, we knocked down Spock2 in the B16F10 melanoma cell line. High SPOCK2 levels were positively associated with good prognosis and long survival rate of patients with melanoma. Spock2 knockdown promoted melanoma cell proliferation by inducing the cell cycle and inhibiting apoptosis. Moreover, Spock2 downregulation significantly increased cell migration and invasion by upregulating MMP2 and MT1-MMP. The increased cell proliferation and migration were inhibited by MAPK inhibitor, and ERK phosphorylation was considerably enhanced in Spock2 knockdown cells. Therefore, Spock2 could function as a tumour suppressor gene to regulate melanoma progression by regulating the MAPK/ERK signalling pathway. Additionally, Spock2 knockdown cell injection induced considerable tumour growth and lung metastasis in C57BL6 mice compared to that in the control group. Our findings suggest that SPOCK2 plays crucial roles in malignant progression of melanoma and functions as a novel therapeutic target of melanoma.

An ensemble-based deep learning model for detection of mutation causing cutaneous melanoma

When the mutation affects the melanocytes of the body, a condition called melanoma results which is one of the deadliest skin cancers. Early detection of cutaneous melanoma is vital for raising the chances of survival. Melanoma can be due to inherited defective genes or due to environmental factors such as excessive sun exposure. The accuracy of the state-of-the-art computer-aided diagnosis systems is unsatisfactory. Moreover, the major drawback of medical imaging is the shortage of labeled data. Generalized classifiers are required to diagnose melanoma to avoid overfitting the dataset. To address these issues, blending ensemble-based deep learning (BEDLM-CMS) model is proposed to detect mutation of cutaneous melanoma by integrating long short-term memory (LSTM), Bi-directional LSTM (BLSTM) and gated recurrent unit (GRU) architectures. The dataset used in the proposed study contains 2608 human samples and 6778 mutations in total along with 75 types of genes. The most prominent genes that function as biomarkers for early diagnosis and prognosis are utilized. Multiple extraction techniques are used in this study to extract the most-prominent features. Afterwards, we applied different DL models optimized through grid search technique to diagnose melanoma. The validity of the results is confirmed using several techniques, including tenfold cross validation (10-FCVT), independent set (IST), and self-consistency (SCT). For validation of the results multiple metrics are used which include accuracy, specificity, sensitivity, and Matthews's correlation coefficient. BEDLM gives the highest accuracy of 97% in the independent set test whereas in self-consistency test and tenfold cross validation test it gives 94% and 93% accuracy, respectively. Accuracy of in self-consistency test, independent set test, and tenfold cross validation test is LSTM (96%, 94%, 92%), GRU (93%, 94%, 91%), and BLSTM (99%, 98%, 93%), respectively. The findings demonstrate that the proposed BEDLM-CMS can be used effectively applied for early diagnosis and treatment efficacy evaluation of cutaneous melanoma.

Tumor Microenvironment as a Therapeutic Target in Melanoma Treatment

The role of the tumor microenvironment in tumor growth and therapy has recently attracted more attention in research and drug development. The ability of the microenvironment to trigger tumor maintenance, progression, and resistance is the main cause for treatment failure and tumor relapse. Accumulated evidence indicates that the maintenance and progression of tumor cells is determined by components of the microenvironment, which include stromal cells (endothelial cells, fibroblasts, mesenchymal stem cells, and immune cells), extracellular matrix (ECM), and soluble molecules (chemokines, cytokines, growth factors, and extracellular vesicles). As a solid tumor, melanoma is not only a tumor mass of monolithic tumor cells, but it also contains supporting stroma, ECM, and soluble molecules. Melanoma cells are continuously in interaction with the components of the microenvironment. In the present review, we focus on the role of the tumor microenvironment components in the modulation of tumor progression and treatment resistance as well as the impact of the tumor microenvironment as a therapeutic target in melanoma.

Dual targeting of melanoma translation by MNK/eIF4E and PI3K/mTOR inhibitors

Melanoma is relatively resistant to chemotherapy, and no targeted therapies are fully effective. The most common mutations in melanoma result in hyperactivation of the mitogen-activated protein kinase (MAPK) and PI3K/AKT/ mTOR pathways responsible for initiating and controlling oncogenic protein translation. This makes both the signaling pathways potentially important therapeutic targets in melanoma. Our studies were carried out on human melanoma cell lines WM793 and 1205 LU with similar genomic alteration (BRAFV600E and PTEN loss). We used a highly specific PI3K/mTOR inhibitor, dactolisib (NVP-BEZ235), and Mnk inhibitor - CGP57380 alone and in combination. Here, we explore the mechanism of action of these drugs alone and in combination, as well as their effect on the viability and invasiveness of melanoma cells. Although when used independently, both drugs suppressed cell proliferation and migration, their combination has additional antitumor effects. We demonstrate that simultaneous inhibition of both pathways may prevent possible drug resistance.

Nanotechnology-based photo-immunotherapy: a new hope for inhibition of melanoma growth and metastasis

Melanoma is the most aggressive form of skin cancer and there is a need for the development of effective anti-melanoma therapies as it shows high metastatic ability and low response rate. In addition, it has been identified that traditional phototherapy could trigger immunogenic cell death (ICD) to activate antitumor immune response, which could not only effectively arrest primary tumor growth, but also exhibit superior effects in terms of anti-metastasis, anti-recurrence for metastatic melanoma treatment However, the limited tumor accumulation of photosensitizers/photothermal agents and immunosuppressive tumor microenvironment severely weaken the immune effects. The application of nanotechnology facilitates a higher accumulation of photosensitizers/photothermal agents at the tumor site, which can thus improve the antitumor effects of photo-immunotherapy (PIT). In this review, we summarize the basic principles of nanotechnology-based PIT and highlight novel nanotechnologies that are expected to enhance the antitumor immune response for improved therapeutic efficacy.

Morphological aspects and therapeutic options in melanoma: a narrative review of the past decade

Melanoma is a malignant cancer of the skin, the incidence of which has been increasing year by year. This neoplasm has high aggressivity as well as the potential for invasion and metastases. Multiple factors related to the proliferation of this type of tumor have been identified, such as exposure to ultraviolet (UV) radiation and specific genetic backgrounds. From a histological and cytological point of view, the most common cells that are found in melanoma are epithelioid or spindle cells. To confirm the diagnosis and the melanocytic origin of the tumor, specific and sensitive markers are used. Also, observation of the behavior of this cancer, including its proliferative properties, has led to the development of multiple therapies, each of which is characteristic of the pathological stage at the time of diagnosis. While surgery is the most important therapeutic and curative option in cases of melanoma in situ, chemotherapy has been the main treatment for advanced stages of melanoma for many years. However, recently, targeted therapy and immunotherapy have changed the approach to treatment. At present, multiple studies are attempting to obtain further data about the tumor microenvironment and investigating how targeting particular molecules can change the prognosis of patients.

Genetics and Genomics of Melanoma: Current Progress and Future Directions

Melanoma is a form of skin cancer that develops in the skin's pigment cells, known as melanocytes, and can spread via blood and the lymphatic system to nearby tissues or distant organs in the body [...].

Correlation Between Endoglin and Malignant Phenotype in Human Melanoma Cells: Analysis of hsa-mir-214 and hsa-mir-370 in Cells and Their Extracellular Vesicles

Endoglin (CD105) is an auxiliary receptor of transforming growth factor (TGF)-β family members that is expressed in human melanomas. It is heterogeneously expressed by primary and metastatic melanoma cells, and endoglin targeting as a therapeutic strategy for melanoma tumors is currently been explored. However, its involvement in tumor development and malignancy is not fully understood. Here, we find that endoglin expression correlates with malignancy of primary melanomas and cultured melanoma cell lines. Next, we have analyzed the effect of ectopic endoglin expression on two miRNAs (hsa-mir-214 and hsa-mir-370), both involved in melanoma tumor progression and endoglin regulation. We show that compared with control cells, overexpression of endoglin in the WM-164 melanoma cell line induces; (i) a significant increase of hsa-mir-214 levels in small extracellular vesicles (EVs) as well as an increased trend in cells; and (ii) significantly lower levels of hsa-mir-370 in the EVs fractions, whereas no significant differences were found in cells. As hsa-mir-214 and hsa-mir-370 are not just involved in melanoma tumor progression, but they can also target endoglin-expressing endothelial cells in the tumor vasculature, these results suggest a complex and differential regulatory mechanism involving the intracellular and extracellular signaling of hsa-mir-214 and hsa-mir-370 in melanoma development and progression.

A novel melanoma prognostic model based on the ferroptosis-related long non-coding RNA

Ferroptosis is an iron-dependent programmed cell death related to the biological process of many kinds of tumors. Long noncoding RNAs (LncRNA) have been found to play essential roles in the tumor, and their functions in the ferroptosis of tumor cells have been partially discovered. However, there is no summary of ferroptosis-related LncRNA and its functions in melanoma. In the present study, we aim to explore the expression profile of ferroptosis-related LncRNA genes and their value in melanoma prognosis by bioinformatics analysis. The expression of ferroptosis-related gene (FRG) from melanoma clinical data was extracted based on the Cancer Genome Atlas (TCGA) database. By screening the RNA expression data of 472 cases of melanoma and 810 cases of normal skin, eighteen ferroptosis-related differential genes were found to be related to the overall survival rate. Furthermore, 384 ferroptosis-related LncRNAs were discovered through constructing the mRNA-LncRNA co-expression network, and ten of them were found with prognostic significance in melanoma by multivariate Cox analysis. Risk assessment showed that the high expression of LncRNA00520 is associated with poor prognosis, while the increased expression of the other LncRNA is beneficial to the prognosis of patients with melanoma. From univariate and multivariate Cox regression analysis, there were ten ferroptosis-related LncRNA risk models towards to be significant independent prognostic factors for patients with melanoma and valuable predictive factors for overall survival (OS)(P<0.05). The ROC curve further suggested that the risk score has relatively reliable predictive ability (AUC=0.718). The protein level of ferroptosis-related genes was verified by the HPA database and IHC test, leading to the discovery that the expressions of ALOX5, PEBP1, ACSL4, and ZEB1 proteins up-regulated in tumor tissues, and existed differences between tumor tissues and normal tissues. In conclusion, we identified ten ferroptosis-related LncRNA and constructed a prognosis model base.

Apprising Diagnostic and Prognostic Biomarkers in Cutaneous Melanoma—Persistent Updating

The incidence of melanoma, a very aggressive skin cancer, has increased over the past few decades. Although there are well-established clinical, dermoscopic and histopathological criteria, the diagnosis is often performed late, which has important implications on the patient’s clinical outcome. Unfortunately, melanoma is one of the most challenging tumors to diagnose because it is a heterogeneous neoplasm at the clinical, histopathological, and molecular level. The use of reliable biomarkers for the diagnosis and monitoring of disease progression is becoming a standard of care in modern medicine. In this review, we discuss the latest studies, which highlight findings from the genomics, epitranscriptomics, proteomics and metabolomics areas, pointing out different genes, molecules and cells as potential diagnostic and prognostic biomarkers in cutaneous melanoma.

VEGF-A promotes the motility of human melanoma cells through the VEGFR1-PI3K/Akt signaling pathway

Vascular endothelial growth factor A (VEGF-A) and its receptors (VEGFR1 and R2) play important roles in the progression of malignant melanoma through tumor angiogenesis. However, it is not clear whether the VEGF-A/VEGFR1 signaling pathway is involved in the proliferation and migration of melanoma cells. Thus, the effect of VEGF-A on cell migration was investigated in human melanoma cell lines. Of several splicing variants of VEGF-A, VEGF₁₆₅ is the most abundant and responsible for VEGF-A biological potency. VEGF₁₆₅ facilitated the migration of melanoma cells in both a chemotactic and chemokinetic manner, but cell proliferation was not affected by VEGF₁₆₅. VEGF₁₆₅ also induced the phosphorylation of Akt. In addition, VEGF₁₆₅-induced cell migration was inhibited significantly by VEGFR1/2 or a VEGFR1-neutralizing antibody. Furthermore, the downregulation of VEGFR1 via the transfection of VEGFR1-targeting antisense oligonucleotides suppressed VEGF₁₆₅-induced cell migration. Moreover, wortmannin, an inhibitor of phosphatidylinositol-3 kinase (PI3K) in the PI3K/Akt pathway, suppressed VEGF₁₆₅-induced Akt phosphorylation and VEGF₁₆₅-induced cell migration. These findings suggest that the motility of melanoma cells is regulated by signals mediated through the PI3K/Akt kinase pathway with the activation of VEGFR1 tyrosine kinase by VEGF₁₆₅. Thus, the downregulation of signaling via VEGF-A/VEGFR1 might be an effective therapeutic approach that could prevent the progression of malignant melanoma.