PTEN signaling pathways in melanoma

Precision Drug Repurposing: A Deep Learning Toolkit for Identifying 34 Hyperpigmentation-Associated Genes and Optimizing Treatment Selection

BACKGROUND

Hyperpigmentation is a skin disorder characterized by a localized darkening of the skin due to increased melanin production. When patients fail first line topical treatments, secondary treatments such as chemical peels and lasers are offered. However, these interventions are not devoid of risks and are associated with postinflammatory hyperpigmentation. In the quest for novel therapeutic potentials, this study aims to investigate computational methods in the identification of new targeted therapies in the treatment of hyperpigmentation.

METHODS

We used a comprehensive approach, which integrated text mining, interpreting gene lists through enrichment analysis and integration of diverse biological information (GeneCodis), protein-protein association networks and functional enrichment analyses (STRING), and plug-in network centrality parameters (Cytoscape) to pinpoint genes closely associated with hyperpigmentation. Subsequently, analysis of drug-gene interactions to identify potential drugs (Cortellis) was utilized to select drugs targeting these identified genes. Lastly, we used Deep Learning Based Drug Repurposing Toolkit (DeepPurpose) to conduct drug-target interaction predictions to ultimately identify candidate drugs with the most promising binding affinities.

RESULTS

Thirty-four hyperpigmentation-related genes were identified by text mining. Eight key genes were highlighted by utilizing GeneCodis, STRING, Cytoscape, gene enrichment, and protein-protein interaction analysis. Thirty-five drugs targeting hyperpigmentation-associated genes were identified by Cortellis, and 29 drugs, including 16 M2PK1 inhibitors, 11 KRAS inhibitors, and 2 BRAF inhibitors were recommended by DeepPurpose.

CONCLUSIONS

The study highlights the promise of advanced computational methodology for identifying potential treatments for hyperpigmentation.

Detection of human papillomavirus (HPV) in malignant melanoma

The most common type of melanoma is cutaneous melanoma (CM). The predominant mutational signature is that of ultraviolet radiation (UVR) exposure. The Cancer Genome Atlas (TCGA) molecular classification includes four major subtypes of CM based on common genetic alterations involving the following genes: BRAF, NRAS, and NF1, with a small fraction being "triple" wild-type. The two main signaling pathway abnormalities in CM are the mitogen-activated protein kinase (MAPK) pathway and the phosphoinositol-3-kinase (PI3K) pathway. Other less common types include mucosal melanomas (MM) and uveal melanoma (UM), which have a significantly different genomic landscape. Although few studies reported rare cases with HPV-positive (HPV+) melanoma, the clinicopathological and molecular characteristic of this entity has not been well-described. Among the 2084 melanoma cases queried at our institution, we identified seven patients diagnosed with HPV+ melanoma (prevalence 0.03 %), including five instances of CM and two of MM. The majority of cases were positive for HPV16 (n = 6). Most of the patients were elderly and with advanced disease (n = 6), although this finding may be attributed to the relative frequency of our institution testing advanced-stage tumors. Histologically, most cases showed high degree of pleomorphism and high mitotic count (5 or more mitoses/mm2) (n = 6). UVR signature was present in the CM, but not in the MM cases. Alterations in either MAPK and/or PI3K pathways were detected in the majority of cases (n = 6). The most common genetic abnormalities detected in this study occurred in the TERT promoter (TERTp) (n = 5), a finding that has been reported to be associated with aggressive disease. Our data shows that while HPV+ melanoma is rare, identifying this disease entity could help guide therapy given the demonstrated genomic alterations.

A Multimodal Drug-Diet-Immunotherapy Combination Restrains Melanoma Progression and Metastasis

The genetic landscape of cancer cells can lead to specific metabolic dependencies for tumor growth. Dietary interventions represent an attractive strategy to restrict the availability of key nutrients to tumors. In this study, we identified that growth of a subset of melanoma was severely restricted by a rationally designed combination therapy of a stearoyl-CoA desaturase (SCD) inhibitor with an isocaloric low-oleic acid diet. Despite its importance in oncogenesis, SCD underwent monoallelic codeletion along with PTEN on chromosome 10q in approximately 47.5% of melanoma, and the other SCD allele was methylated, resulting in very low-SCD expression. Although this SCD-deficient subset was refractory to SCD inhibitors, the subset of PTEN wild-type melanoma that retained SCD was sensitive. As dietary oleic acid could potentially blunt the effect of SCD inhibitors, a low oleic acid custom diet was combined with an SCD inhibitor. The combination reduced monounsaturated fatty acids and increased saturated fatty acids, inducing robust apoptosis and growth suppression and inhibiting lung metastasis with minimal toxicity in preclinical mouse models of PTEN wild-type melanoma. When combined with anti-PD1 immunotherapy, the SCD inhibitor improved T-cell functionality and further constrained melanoma growth in mice. Collectively, these results suggest that optimizing SCD inhibitors with diets low in oleic acid may offer a viable and efficacious therapeutic approach for improving melanoma treatment. Significance: Blockade of endogenous production of fatty acids essential for melanoma combined with restriction of dietary intake blocks tumor growth and enhances response to immunotherapy, providing a rational drug-diet treatment regimen for melanoma.

Spatial transcriptomics analysis identifies a tumor-promoting function of the meningeal stroma in melanoma leptomeningeal disease

Leptomeningeal disease (LMD) remains a rapidly lethal complication for late-stage melanoma patients. Here, we characterize the tumor microenvironment of LMD and patient-matched extra-cranial metastases using spatial transcriptomics in a small number of clinical specimens (nine tissues from two patients) with extensive in vitro and in vivo validation. The spatial landscape of melanoma LMD is characterized by a lack of immune infiltration and instead exhibits a higher level of stromal involvement. The tumor-stroma interactions at the leptomeninges activate tumor-promoting signaling, mediated through upregulation of SERPINA3. The meningeal stroma is required for melanoma cells to survive in the cerebrospinal fluid (CSF) and promotes MAPK inhibitor resistance. Knocking down SERPINA3 or inhibiting the downstream IGR1R/PI3K/AKT axis results in tumor cell death and re-sensitization to MAPK-targeting therapy. Our data provide a spatial atlas of melanoma LMD, identify the tumor-promoting role of meningeal stroma, and demonstrate a mechanism for overcoming microenvironment-mediated drug resistance in LMD.

PSMA2 promotes glioma proliferation and migration via EMT

BACKGROUND

Gliomas advance rapidly and are associated with a poor prognosis. Epithelial-mesenchymal transition (EMT) accelerates the progression of gliomas, exerting a pivotal role in glioma development. Proteasome subunit alpha type-2 (PSMA2) exhibits high expression levels in gliomas. however, its specific involvement in glioma progression and its correlation with EMT remain elusive. This study aims to elucidate the role of PSMA2 in glioma progression and its potential association with EMT.

METHODS

Online tools were employed to analyze the expression patterns and survival curves of PSMA2 in gliomas. The relationship between PSMA2 and various characteristics of glioma patients was investigated using data from the TCGA and CGGA databases. In vitro, cell proliferation and migration were assessed through CCK-8, colony formation, and transwell assays. Furthermore, a tumor xenograft model in nude mice was established to evaluate in vivo tumorigenesis. Protein binding to PSMA2 was scrutinized using co-immunoprecipitation MS (co-IP MS). The potential biological functions and molecular pathways associated with PSMA2 were explored through GO analysis and KEGG analysis, and the correlation between PSMA2 and EMT was validated through correlation analysis and Western blot experiments.

RESULTS

Bioinformatics analysis revealed a significant upregulation of PSMA2 across various cancers, with particularly heightened expression in gliomas. Moreover, elevated PSMA2 levels were correlated with advanced tumor stages and diminished survival rates among glioma patients. Inhibition of PSMA2 demonstrated a pronounced suppressive effect on glioma cell proliferation, both in vitro and in vivo. Knockdown of PSMA2 also impeded the migratory capacity of glioma cells. GO and KEGG enrichment analyses indicated that PSMA2-binding proteins (identified through Co-IP-MS) were associated with cell adhesion molecule binding and cadherin binding. Western blot results further confirmed the role of PSMA2 in promoting epithelial-mesenchymal transition (EMT) in glioma cells.

CONCLUSION

Our study provides evidence supporting the role of PSMA2 as a regulatory factor in EMT and suggests its potential as a prognostic biomarker for glioma progression.

Pholiotic acid promotes apoptosis in human metastatic melanoma cells

Mushrooms produce a great variety of secondary metabolites that can be successful in both prevention and treatment of various cancers. In particular, higher Basidiomycete mushrooms contain various types of biologically active low-molecular compounds in fruiting bodies with suggested anticarcinogenic effects. The polyamine analogue {(2R)-2-[(S)-3-hydroxy-3-methylglutaryloxy] putrescine dicinnamamide} indicated with the name pholiotic acid, isolated for the first time by us from the fruiting bodies of the Basidiomycete Pholiota spumosa (Fr.) Sing. (Strophariaceae), inhibited the viability of human prostate cancer cells, such as other polyamine synthetic analogues that have shown antitumor activity in several types of cancer, including melanoma. Melanoma is an aggressive skin cancer that can metastasize to other organs and presents a high resistance to conventional therapies. In light of these considerations, the present study was therefore designed to assess whether this putrescine derivative could inhibit the growth of human metastatic melanoma cell lines, M14 and A2058. The results obtained demonstrate that this natural compound, at 12.5-50 μM concentration, was able to reduce cell viability of both cancer cells inducing cell death by intrinsic apoptotic pathway that probably involves PTEN activity, inhibition of Hsp70 expression and reactive oxygen species production. On the other hand, the increased expression of enzymes involved in polyamine catabolism trigger apoptotic cell death leading to polyamine depletion and generation of reactive oxygen species as by-products. In conclusion, these findings, starting point for further investigation, implement available our data to support pholiotic acid as an attractive potential chemopreventive agent, and provide a basis for further research into the use of this polyamine derivative as potential anticancer agent for melanoma in combination with existing therapies to improve treatment efficacy and overcome the obstacle of drug resistance.

The Role of the PTEN Tumor Suppressor Gene and Its Anti-Angiogenic Activity in Melanoma and Other Cancers

Human malignant melanoma and other solid cancers are largely driven by the inactivation of tumor suppressor genes and angiogenesis. Conventional treatments for cancer (surgery, radiation therapy, and chemotherapy) are employed as first-line treatments for solid cancers but are often ineffective as monotherapies due to resistance and toxicity. Thus, targeted therapies, such as bevacizumab, which targets vascular endothelial growth factor, have been approved by the US Food and Drug Administration (FDA) as angiogenesis inhibitors. The downregulation of the tumor suppressor, phosphatase tensin homolog (PTEN), occurs in 30-40% of human malignant melanomas, thereby elucidating the importance of the upregulation of PTEN activity. Phosphatase tensin homolog (PTEN) is modulated at the transcriptional, translational, and post-translational levels and regulates key signaling pathways such as the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) and mitogen-activated protein kinase (MAPK) pathways, which also drive angiogenesis. This review discusses the inhibition of angiogenesis through the upregulation of PTEN and the inhibition of hypoxia-inducible factor 1 alpha (HIF-1-α) in human malignant melanoma, as no targeted therapies have been approved by the FDA for the inhibition of angiogenesis in human malignant melanoma. The emergence of nanocarrier formulations to enhance the pharmacokinetic profile of phytochemicals that upregulate PTEN activity and improve the upregulation of PTEN has also been discussed.

Spatial transcriptomics analysis identifies a unique tumor-promoting function of the meningeal stroma in melanoma leptomeningeal disease

Leptomeningeal disease (LMD) remains a rapidly lethal complication for late-stage melanoma patients. The inaccessible nature of the disease site and lack of understanding of the biology of this unique metastatic site are major barriers to developing efficacious therapies for patients with melanoma LMD. Here, we characterize the tumor microenvironment of the leptomeningeal tissues and patient-matched extra-cranial metastatic sites using spatial transcriptomic analyses with in vitro and in vivo validation. We show the spatial landscape of melanoma LMD to be characterized by a lack of immune infiltration and instead exhibit a higher level of stromal involvement. We show that the tumor-stroma interactions at the leptomeninges activate pathways implicated in tumor-promoting signaling, mediated through upregulation of SERPINA3 at the tumor-stroma interface. Our functional experiments establish that the meningeal stroma is required for melanoma cells to survive in the CSF environment and that these interactions lead to a lack of MAPK inhibitor sensitivity in the tumor. We show that knocking down SERPINA3 or inhibiting the downstream IGR1R/PI3K/AKT axis results in re-sensitization of the tumor to MAPK-targeting therapy and tumor cell death in the leptomeningeal environment. Our data provides a spatial atlas of melanoma LMD, identifies the tumor-promoting role of meningeal stroma, and demonstrates a mechanism for overcoming microenvironment-mediated drug resistance unique to this metastatic site.

Cutaneous Melanoma: A Review of Multifactorial Pathogenesis, Immunohistochemistry, and Emerging Biomarkers for Early Detection and Management

Cutaneous melanoma (CM) is an increasingly significant public health concern. Due to alarming mortality rates and escalating incidence, it is crucial to understand its etiology and identify emerging biomarkers for improved diagnosis and treatment strategies. This review aims to provide a comprehensive overview of the multifactorial etiology of CM, underscore the importance of early detection, discuss the molecular mechanisms behind melanoma development and progression, and shed light on the role of the potential biomarkers in diagnosis and treatment. The pathogenesis of CM involves a complex interplay of genetic predispositions and environmental exposures, ultraviolet radiation exposure being the predominant environmental risk factor. The emergence of new biomarkers, such as novel immunohistochemical markers, gene mutation analysis, microRNA, and exosome protein expressions, holds promise for improved early detection, and prognostic and personalized therapeutic strategies.

Phosphatase and Tensin Homolog (PTEN) Expression as a Surrogate Biomarker Correlated With the Depth of Invasion in Cutaneous Malignant Melanoma

Objective The aim of this study is to evaluate the expression of the phosphatase and tensin homolog (PTEN), which is a tumor suppressor gene that is implicated in the pathogenesis of cutaneous malignant melanoma, in normal skin and melanoma tissue samples. The study also aimed to correlate PTEN expression levels with various clinicopathological parameters of melanoma lesions, thus highlighting the utility of PTEN expression as a prognostic biomarker for melanoma. Study design Immunohistochemistry (IHC) staining was performed on tissue microarray samples representing normal skin and melanoma biopsies of different clinicopathological parameters. Tissue photomicrographs were evaluated with Aperio ImageScope, which has a positive-pixel-counting algorithm built in. Subsequently, a histochemical score (H-score) was derived from the percentage of positive cells (%-staining) and their staining intensity. The H-scores were averaged in groups of tissue samples representing the different melanomas' tumor (T), node (N), and distant metastasis (M), also known as TNM parameters, as set forth by the American Joint Committee on Cancer (AJCC) classification. The mean H-scores were statistically compared using a two-tailed unpaired t-test. Results The PTEN protein expression was measured by IHC and found to be correlated with tumor thickness (T), which is a reliable indicator for survival rates. Specifically, PTEN was significantly downregulated in tumors with a thickness over 2 mm (T3+T4) compared to tumors with a thickness at or below 2 mm (T1+T2). Conclusions The PTEN protein expression, as measured by immunohistochemistry, helped differentiate between tumors with a thickness over 2 mm and tumors with a thickness at or below 2 mm, suggesting PTEN as a potential surrogate marker for the melanoma's invasion depth along with possible prognostic implications. Longitudinal studies evaluating risk stratification based on the expression of PTEN are needed to establish the utility of this promising biomarker in the clinic as an adjunct for pathological examination.

Simultaneous Thoracic Spine Metastatic Melanoma and Pre-existing Prostate Adenocarcinoma: A Unique Case Presentation and Literature Review

In melanoma patients, distant metastases frequently manifest in the skin, lung, brain, liver, bone, and intestine. Notably, bone metastasis predominantly occurs within the axial skeleton, with the lumbar and thoracic spines being the most affected regions. Conversely, prostate cancer often disseminates to the bone, lung, liver, pleura, and adrenal glands. The spinal column, particularly the lumbar region, frequently harbors metastases in prostate cancer cases. Given the proximity of axial lesions to the spinal cord, patients commonly experience pain, weakness, and urinary dysfunction. This article presents a compelling case report of a patient initially diagnosed with metastatic prostate cancer, who later exhibited a metastatic lesion in the thoracic spine, subsequently identified as originating from acral melanoma on the plantar surface of the right foot. Histopathological examination confirmed the presence of acral melanoma in both the spine and the right foot. The patient received comprehensive treatment for advanced melanoma from a multidisciplinary team comprising medical and radiation oncologists. Considering the overlapping pathophysiology of prostate cancer and melanoma, simultaneous screening for both diseases in cases where one is detected could yield significant benefits, including enhanced morbidity and mortality outcomes and the facilitation of early detection for secondary malignancies.

New Treatment Horizons in Uveal and Cutaneous Melanoma

Melanoma is a complex and heterogeneous malignant tumor with distinct genetic characteristics and therapeutic challenges in both cutaneous melanoma (CM) and uveal melanoma (UM). This review explores the underlying molecular features and genetic alterations in these melanoma subtypes, highlighting the importance of employing specific model systems tailored to their unique profiles for the development of targeted therapies. Over the past decade, significant progress has been made in unraveling the molecular and genetic characteristics of CM and UM, leading to notable advancements in treatment options. Genetic mutations in the mitogen-activated protein kinase (MAPK) pathway drive CM, while UM is characterized by mutations in genes like GNAQ, GNA11, BAP1, EIF1AX, and SF3B1. Chromosomal aberrations, including monosomy 3 in UM and monosomy 10 in CM, play significant roles in tumorigenesis. Immune cell infiltration differs between CM and UM, impacting prognosis. Therapeutic advancements targeting these genetic alterations, including oncolytic viruses and immunotherapies, have shown promise in preclinical and clinical studies. Oncolytic viruses selectively infect malignant cells, inducing oncolysis and activating antitumor immune responses. Talimogene laherparepvec (T-VEC) is an FDA-approved oncolytic virus for CM treatment, and other oncolytic viruses, such as coxsackieviruses and HF-10, are being investigated. Furthermore, combining oncolytic viruses with immunotherapies, such as CAR-T cell therapy, holds great potential. Understanding the intrinsic molecular features of melanoma and their role in shaping novel therapeutic approaches provides insights into targeted interventions and paves the way for more effective treatments for CM and UM.

Recent Perspective of Lactobacillus in Reducing Oxidative Stress to Prevent Disease

During oxidative stress, an important factor in the development of many diseases, cellular oxidative and antioxidant activities are imbalanced due to various internal and external factors such as inflammation or diet. The administration of probiotic Lactobacillus strains has been shown to confer a range of antibacterial, anti-inflammatory, antioxidant, and immunomodulatory effects in the host. This review focuses on the potential role of oxidative stress in inflammatory bowel diseases (IBD), cancer, and liver-related diseases in the context of preventive and therapeutic effects associated with Lactobacillus. This article reviews studies in cell lines and animal models as well as some clinical population reports that suggest that Lactobacillus could alleviate basic symptoms and related abnormal indicators of IBD, cancers, and liver damage, and covers evidence supporting a role for the Nrf2, NF-κB, and MAPK signaling pathways in the effects of Lactobacillus in alleviating inflammation, oxidative stress, aberrant cell proliferation, and apoptosis. This review also discusses the unmet needs and future directions in probiotic Lactobacillus research including more extensive mechanistic analyses and more clinical trials for Lactobacillus-based treatments.

Role of histone methylation in skin cancers: Histone methylation-modifying enzymes as a new class of targets for skin cancer treatment

Histone methylation, one of the most prominent epigenetic modifications, plays a vital role in gene transcription, and aberrant histone methylation levels cause tumorigenesis. Histone methylation is a reversible enzyme-dependent reaction, and histone methyltransferases and demethylases are involved in this reaction. This review addresses the biological and clinical relevance of these histone methylation-modifying enzymes for skin cancer. In particular, the roles of histone lysine methyltransferases, histone arginine methyltransferase, lysine-specific demethylases, and JmjC demethylases in skin cancer are discussed in detail. In addition, we summarize the efficacy of several epigenetic inhibitors targeting histone methylation-modifying enzymes in cutaneous cancers, such as basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. In conclusion, we propose histone methylation-modifying enzymes as novel targets for next-generation pharmaceuticals in the treatment of skin cancers and further provide a rationale for the development of epigenetic drugs (epidrugs) that target specific histone methylases/demethylases in cutaneous tumors.

PSMA2 knockdown impacts expression of proteins involved in immune and cellular stress responses in human lung cells

Proteasome subunit alpha type-2 (PSMA2) is a critical component of the 20S proteasome, which is the core particle of the 26S proteasome complex and is involved in cellular protein quality control by recognizing and recycling defective proteins. PSMA2 expression dysregulation has been detected in different human diseases and viral infections. No study yet has reported PSMA2 knockdown (KD) effects on the cellular proteome.

METHODS

We used SOMAScan, an aptamer-based multiplexed technique, to measure >1300 human proteins to determine the impact of PSMA2 KD on A549 human lung epithelial cells.

RESULTS

PSMA2 KD resulted in significant dysregulation of 52 cellular proteins involved in different bio-functions, including cellular movement and development, cell death and survival, and cancer. The immune system and signal transduction were the most affected cellular functions. PSMA2 KD caused dysregulation of several signaling pathways involved in immune response, cytokine signaling, organismal growth and development, cellular stress and injury (including autophagy and unfolded protein response), and cancer responses.

CONCLUSIONS

In summary, this study helps us better understand the importance of PSMA2 in different cellular functions, signaling pathways, and human diseases.

Metabolic Health, Mitochondrial Fitness, Physical Activity, and Cancer

Cancer continues to be a significant global health issue. Traditional genetic-based approaches to understanding and treating cancer have had limited success. Researchers are increasingly exploring the impact of the environment, specifically inflammation and metabolism, on cancer development. Examining the role of mitochondria in this context is crucial for understanding the connections between metabolic health, physical activity, and cancer. This study aimed to review the literature on this topic through a comprehensive narrative review of various databases including MedLine (PubMed), Cochrane (Wiley), Embase, PsychINFO, and CinAhl. The review highlighted the importance of mitochondrial function in overall health and in regulating key events in cancer development, such as apoptosis. The concept of "mitochondrial fitness" emphasizes the crucial role of mitochondria in cell metabolism, particularly their oxidative functions, and how proper function can prevent replication errors and regulate apoptosis. Engaging in high-energy-demanding movement, such as exercise, is a powerful intervention for improving mitochondrial function and increasing resistance to environmental stressors. These findings support the significance of considering the role of the environment, specifically inflammation and metabolism, in cancer development and treatment. Further research is required to fully understand the mechanisms by which physical activity improves mitochondrial function and potentially reduces the risk of cancer.

SETD1A promotes the proliferation and glycolysis of nasopharyngeal carcinoma cells by activating the PI3K/Akt pathway

Nasopharyngeal carcinoma is one of the common malignant tumors that the pathogenesis has not yet been completely defined. SETD1A (histone lysine methyltransferase SET domain-containing 1A) is related to the occurrence of various cancers. However, the role of SETD1A in nasopharyngeal carcinoma remains unclear. The SETD1A overexpression vector, si-NC, si-SETD1A#1, and si-SETD1A#2 were transfected into nasopharyngeal carcinoma cells to overexpress or knockdown SETD1A expression. The assay of biofunction was used to explore the role of SETD1A in nasopharyngeal carcinoma cells. The assay of glucose uptake, lactate release, ATP level, western blot, cell proliferation, and cellular apoptosis analysis were performed to investigate the potential mechanism of SETD1A regulation in nasopharyngeal carcinoma. This study was the first to show that SETD1A was upregulated in nasopharyngeal carcinoma cells and the overexpression of SETD1A significantly promoted the cell proliferation and glycolysis and suppressed the cellular apoptosis. Moreover, SETD1A enhances aerobic glycolysis and cell biological function of nasopharyngeal carcinoma cells via PI3K/AKT signaling pathway. SETD1A induced PI3K/AKT activation and subsequently prevented cellular apoptosis. In conclusion, this study identified overexpressed SETD1A as a positive regulator of proliferation that induced nasopharyngeal carcinoma cells’ aerobic glycolysis via PI3K/AKT signaling activation in vitro. This study laid a strong foundation for unveiling the precise anticancer mechanism of SETD1A. The SETD1A may become a novel biomarker for further inhibitor design to obstruct the PI3K/AKT-dependent nasopharyngeal carcinoma progression.

Cutaneous Melanoma versus Vulvovaginal Melanoma-Risk Factors, Pathogenesis and Comparison of Immunotherapy Efficacy

Cutaneous melanoma is a relatively common neoplasm, with fairly well understood pathogenesis, risk factors, prognosis and therapeutic protocols. The incidence of this disease is increasing every year. The situation is different for rare malignancies such as vulvar melanomas and for the even rarer vaginal melanomas. The risk factors for vulvovaginal tumors are not fully understood. The basis of treatment in both cases is surgical resection; however, other types of treatments such as immunotherapy are available. This paper focuses on comparing the pathogenesis and risk factors associated with these neoplasms as well as the efficacy of two groups of drugs-anti-PD-L1 and anti-CTLA4 inhibitors-against both cutaneous melanoma and melanoma of the lower genital tract (vulva and vagina). In the case of cutaneous melanoma, the situation looks more optimistic than for vulvovaginal melanoma, which has a much worse prognosis and, as it turns out, shows a poorer response to immune therapy.

Ulcerated Cutaneous Melanoma: A Review of the Clinical, Histologic, and Molecular Features Associated with a Clinically Aggressive Histologic Phenotype

The presence of ulceration in melanoma is associated with poor clinical outcomes and is the third most powerful predictor of survival in the AJCC Melanoma Staging System after tumor thickness and mitotic activity. The aggressive biological behavior associated with ulceration has been hypothesized to be the result of an intrinsic biological attribute that favors dissemination and presents locally with the loss of epidermal integrity. Among the features of ulcerated melanoma, many show promise as potential prognostic tools, markers of differential immunogenicity and indicators of oncogenic drivers of invasion and metastasis. The incidence of ulcerated melanoma is greater in males, increases with age and with systemic inflammatory risk factors (diabetes, smoking, low vitamin D, elevated body mass index). Patients with ulcerated primary tumors seem to exclusively benefit from adjuvant interferon (IFN) therapy, which is likely the consequence of an altered tumor microenvironment. When ulceration is present, there is a higher density of macrophages and dendritic cells and enhanced expression of pro-inflammatory cytokines, such as IL-6. There is also an increased expression of proteins involved in tumor antigen presentation in ulcerated melanomas. Histologically, vascular density, vasculogenic mimicry and angiotropism are all significantly correlated with ulceration in melanoma. The presence of ulceration is associated with reduced protein expression of E-cadherin and PTEN and elevated levels of N-cadherin and the matrix metalloproteinases. Differential microRNA expression also holds promise as a potential prognostic biomarker of malignancy and disease spread within the setting of ulceration. However, the molecular and cellular differences associated with the ulcerated state are complex and further study will aid in determining how these differences can be harnessed to improve care for patients with melanoma.

The role of dual-specificity phosphatase 3 in melanocytic oncogenesis

Dual-specificity phosphatase 3 (DUSP3), also known as Vaccinia H1-related phosphatase, is a protein tyrosine phosphatase that typically performs its major role in the regulation of multiple cellular functions through the dephosphorylation of its diverse and constantly expanding range of substrates. Many of the substrates described so far as well as alterations in the expression or the activity of DUSP3 itself are associated with the development and progression of various types of neoplasms, indicating that DUSP3 may be an important player in oncogenesis and a promising therapeutic target. This review focuses exclusively on DUSP3's contribution to either benign or malignant melanocytic oncogenesis, as many of the established culprit pathways and mechanisms constitute DUSP3's regulatory targets, attempting to synthesize the current knowledge on the matter. The spectrum of the DUSP3 interactions analyzed in this review covers substrates implicated in cellular growth, cell cycle, proliferation, survival, apoptosis, genomic stability/repair, adhesion and migration of tumor melanocytes. Furthermore, the speculations raised, based on the evidence to date, may be considered a fundament for potential research regarding the oncogenesis, evolution, management and therapeutics of melanocytic tumors.

Both phosphorylation and phosphatase activity of PTEN are required to prevent replication fork progression during stress by inducing heterochromatin

PTEN is a tumor suppressor protein frequently altered in various cancers. PTEN-null cells have a characteristic of rapid proliferation with an unstable genome. Replication stress is one of the causes of the accumulation of genomic instability if not sensed by the cellular signaling. Though PTEN-null cells have shown to be impaired in replication progression and stalled fork recovery, the association between the catalytic function of PTEN regulated by posttranslational modulation and cellular response to replication stress has not been studied explicitly. To understand molecular mechanism, we find that PTEN-null cells display unrestrained replication fork progression with accumulation of damaged DNA after treatment with aphidicolin which can be rescued by ectopic expression of full-length PTEN, as evident from DNA fiber assay. Moreover, the C-terminal phosphorylation (Ser 380, Thr 382/383) of PTEN is essential for its chromatin association and sensing replication stress that, in response, induce cell cycle arrest. Further, we observed that PTEN induces HP1α expression and H3K9me3 foci formation in a C-terminal phosphorylation-dependent manner. However, phosphatase dead PTEN cannot sense replication stress though it can be associated with chromatin. Together, our results suggest that DNA replication perturbation by aphidicolin enables chromatin association of PTEN through C-terminal phosphorylation, induces heterochromatin formation by stabilizing and up-regulating H3K9me3 foci and augments CHK1 activation. Thereby, PTEN prevents DNA replication fork elongation and simultaneously causes G1-S phase cell cycle arrest to limit cell proliferation in stress conditions. Thus PTEN act as stress sensing protein during replication arrest to maintain genomic stability.

PTEN as a target in melanoma

PTEN is a well-known tumour suppressor protein that is frequently found to be mutated, inactivated or deleted in a wide range of different cancers. Its tumour suppressive properties result predominantly from its inhibitory effects on the PI3K-AKT signalling pathway. In melanoma, numerous different PTEN mutations have been identified in both melanoma cell lines and melanoma tissue. A number of different molecules can act on PTEN to either promote its suppression of melanoma, while other molecules may antagonise PTEN to inhibit its mechanism of action against melanoma. This review will discuss how the interactions of PTEN with other molecules may have a positive or negative impact on melanoma pathogenesis, giving rise to the potential for PTEN-targeted therapies against melanoma.

PTEN: A novel target for vitamin D in melanoma

Melanoma is the most dangerous form of skin cancer, with poor prognosis in advanced stages. Vitamin D, also produced by ultraviolet radiation, is known for its anti-proliferative properties in some cancers including melanoma. While vitamin D deficiency has been associated with advanced melanoma stage and higher levels of vitamin D have been associated with better outcomes, the role for vitamin D in melanoma remains unclear. Vitamin D synthesis is initiated upon UVB exposure of skin cells and results in formation of the active metabolite 1,25-dihydroxyvitamin D3 (1,25D). We have previously demonstrated that 1,25D plays a role in protection against ultraviolet radiation-induced DNA damage, immune suppression, and skin carcinogenesis. In this study 1,25D significantly reduced cell viability and increased caspase levels in human melanoma cell lines. This effect was not present in cells that lacked both phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a well-known tumour suppressor, and the vitamin D receptor (VDR). PTEN is frequently lost or mutated in melanoma. Incubation of selected melanoma cell lines with 1,25D resulted in significant increases in PTEN levels and downregulation of the AKT pathway and its downstream effectors. This suggests that 1,25D may act to reduce melanoma cell viability by targeting PTEN.

WDR34 affects PI3K/Akt and Wnt/β-catenin pathways to regulates malignant biological behaviors of glioma cells

PURPOSE

Glioma is the most prevalent primary intracranial tumor globally. WDR34, a member of the WDR superfamily with five WD40 repeats, is involved in the pathogenesis of several tumors. However, the role of WDR34 in glioma progression is unknown.

METHODS

The expression and prognostic significance of WDR34 in glioma patients were analyzed using GEPIA. WDR34 expression was detected by qRT-PCR. Western blot was employed to determine the expression of Ki67, proliferating cell nuclear antigen (PCNA), matrix metallopeptidase (MMP)2, MMP9, phosphatase and tensin homolog, protein kinase B (Akt), phosphorylated Akt, β-catenin, and c-Myc. CCK-8, BrdU incorporation assay, Transwell invasion assay, flow cytometry analysis, and measurement of caspase-3 and caspase-9 activities were conducted to examine the effects of WDR34 knockdown on glioma cells.

RESULTS

WDR34 was upregulated in glioma, which predicted a poor prognosis in glioma patients. WDR34 knockdown inhibited cell proliferation and reduced the expression of Ki67 and PCNA in glioma cells. WDR34 knockdown repressed the invasive ability of glioma cells by decreasing MMP-2 and MMP-9 expression. WDR34 knockdown increased the apoptotic rate and caspase-3 and caspase-9 activities in glioma cells. The PI3K/Akt and Wnt/β-catenin pathways were inhibited after WDR34 knockdown in glioma cells. Moreover, overexpression of Akt or β-catenin reversed the function of WDR34 knockdown on proliferation, invasion, and apoptosis. WDR34 knockdown reduced tumor growth in vivo.

CONCLUSIONS

WDR34 knockdown inhibited malignant biological behaviors of glioma cells by inactivating the PI3K/Akt and Wnt/β-catenin signaling cascades.

Nevi, dysplastic nevi, and melanoma: Molecular and immune mechanisms involving the progression

Melanocytic nevi, dysplastic nevi, and melanoma are all derived from the pigment-producing cells, namely melanocytes. Concerning the clinical spectrum, cutaneous melanoma is the most aggressive skin cancer with a low survival rate, while nevi are the most common benign lesions in the general population, and dysplastic nevi place in between nevi and melanoma. Ultraviolet (UV) radiation is a well-recognized extrinsic risk factor for all three. BRAF^V600E is a well-recognized driver mutation that activates the RAS-BRAF-mitogen-activated protein kinase (MAPK) signaling pathway among 40%–60% of melanoma cases. Interestingly, BRAF^V600E mutation is detected even more in acquired nevi, approximately 80%. However, in nevi, several tumor suppressors such as p53 and phosphatase and tensin homolog (PTEN) are intact, and senescence factors, including p15^INK4b, p16^INK4a, p19, and senescence-associated acidic β-galactosidase, are expressed, leading to cell senescence and cell cycle arrest. Although loss of p53 function is rarely found in melanoma, decreased or loss of PTEN with an activated PI3k/Akt signaling pathway is common in nevi, which may abolish senescence status and allow further progression into dysplastic nevi or melanoma. At present, mouse models closely resembling human nevi are used for investigating these phenomena. Melanocortin 1 receptor deficiency, an intrinsic risk factor for melanomagenesis, is related to the production of procarcinogenic pheomelanin and the inhibition of PTEN function. Immune response escape via programmed cell death-1/programmed cell death ligand-1 interaction plays further roles in monitoring the spectrum. Here, we review the current literature on the molecular and immune mechanisms involving the transition from benign nevi to malignant melanoma.

The role of PI3'-lipid signalling in melanoma initiation, progression and maintenance

Phosphatidylinositol-3'-kinases (PI3Ks) are a family of lipid kinases that phosphorylate the 3' hydroxyl (OH) of the inositol ring of phosphatidylinositides (PI). Through their downstream effectors, PI3K generated lipids (PI3K-lipids hereafter) such as PI(3,4,5)P3 and PI(3,4)P2 regulate myriad biochemical and biological processes in both normal and cancer cells including responses to growth hormones and cytokines; the cell division cycle; cell death; cellular growth; angiogenesis; membrane dynamics; and autophagy and many aspects of cellular metabolism. Engagement of receptor tyrosine kinase by their cognate ligands leads to activation of members of the Class I family of PI3'-kinases (PI3Kα, β, δ & γ) leading to accumulation of PI3K-lipids. Importantly, PI3K-lipid accumulation is antagonized by the hydrolytic action of a number of PI3K-lipid phosphatases, most notably the melanoma suppressor PTEN (lipid phosphatase and tensin homologue). Downstream of PI3K-lipid production, the protein kinases AKT1-3 are believed to be key effectors of PI3'-kinase signalling in cells. Indeed, in preclinical models, activation of the PI3K→AKT signalling axis cooperates with alterations such as expression of the BRAFV600E oncoprotein kinase to promote melanoma progression and metastasis. In this review, we describe the different classes of PI3K-lipid effectors, and how they may promote melanomagenesis, influence the tumour microenvironment, melanoma maintenance and progression to metastatic disease. We also provide an update on both FDA-approved or experimental inhibitors of the PI3K→AKT pathway that are currently being evaluated for the treatment of melanoma either in preclinical models or in clinical trials.

Interleukin-8 in Melanoma Pathogenesis, Prognosis and Therapy-An Integrated View into Other Neoplasms and Chemokine Networks

Cutaneous melanoma accounts for only about 7% of skin cancers but is causing almost 90% of deaths. Melanoma cells have a distinct repertoire of mutations from other cancers, a high plasticity and degree of mimicry toward vascular phenotype, stemness markers, versatility in evading and suppress host immune control. They exert a significant influence on immune, endothelial and various stromal cells which form tumor microenvironment. The metastatic stage, the leading cause of mortality in this neoplasm, is the outcome of a complex, still poorly understood, cross-talk between tumor and other cell phenotypes. There is accumulating evidence that Interleukin-8 (IL-8) is emblematic for advanced melanomas. This work aimed to present an updated status of IL-8 in melanoma tumor cellular complexity, through a comprehensive analysis including data from other chemokines and neoplasms. The multiple processes and mechanisms surveyed here demonstrate that IL-8 operates following orchestrated programs within signaling webs in melanoma, stromal and vascular cells. Importantly, the yet unknown molecularity regulating IL-8 impact on cells of the immune system could be exploited to overturn tumor fate. The molecular and cellular targets of IL-8 should be brought into the attention of even more intense scientific exploration and valorization in the therapeutical management of melanoma.

Enhancing Therapeutic Approaches for Melanoma Patients Targeting Epigenetic Modifiers

Melanoma is the least common but deadliest type of skin cancer. Melanomagenesis is driven by a series of mutations and epigenetic alterations in oncogenes and tumor suppressor genes that allow melanomas to grow, evolve, and metastasize. Epigenetic alterations can also lead to immune evasion and development of resistance to therapies. Although the standard of care for melanoma patients includes surgery, targeted therapies, and immune checkpoint blockade, other therapeutic approaches like radiation therapy, chemotherapy, and immune cell-based therapies are used for patients with advanced disease or unresponsive to the conventional first-line therapies. Targeted therapies such as the use of BRAF and MEK inhibitors and immune checkpoint inhibitors such as anti-PD-1 and anti-CTLA4 only improve the survival of a small subset of patients. Thus, there is an urgent need to identify alternative standalone or combinatorial therapies. Epigenetic modifiers have gained attention as therapeutic targets as they modulate multiple cellular and immune-related processes. Due to melanoma's susceptibility to extrinsic factors and reversible nature, epigenetic drugs are investigated as a therapeutic avenue and as adjuvants for targeted therapies and immune checkpoint inhibitors, as they can sensitize and/or reverse resistance to these therapies, thus enhancing their therapeutic efficacy. This review gives an overview of the role of epigenetic changes in melanoma progression and resistance. In addition, we evaluate the latest advances in preclinical and clinical research studying combinatorial therapies and discuss the use of epigenetic drugs such as HDAC and DNMT inhibitors as potential adjuvants for melanoma patients.

Genome-scale DNA methylation analysis identifies repeat element alterations that modulate the genomic stability of melanocytic nevi

Acquired melanocytic nevi grow and persist in a stable form into adulthood. Using genome-wide methylation profiling, we evaluated 32 histopathologically and dermoscopically characterized nevi, to identify key epigenetic regulatory mechanisms involved in nevogenesis. Benign (69% globular and 31% non-specific dermoscopic pattern) and dysplastic (95% reticular/nonspecific dermoscopic pattern) nevi were dissimilar with only two shared differentially methylated (DM) loci. Benign nevi demonstrated an increase in both genome-scale methylation and methylation of Alu/LINE-1 retrotransposable elements, a marker of genomic stability, as well as global methylation. In contrast, dysplastic nevi showed evidence for genomic instability via hypomethylation of Alu/LINE-1 (Alu; P=0.00019 and LINE-1; P=0.000035). Using dermoscopic classifications, reticular/non-specific patterned nevi had 59,572 CpG DM loci (Q < 0.05), whereas globular nevi had no significant DM loci. In reticular/non-specific patterned nevi, the tumor suppressor PTEN had the greatest proportion of hypermethylated CpG loci in its promoter region compared to all other assayed gene promoters. The relative activity of reticular/non-specific nevi was evidenced by 50,720 hypomethylated loci being enriched for accessible chromatin, and 8,852 hypermethylated loci strongly enriched, for example, marks of active gene promoters, which suggests that gain of DNA methylation observed in these nevus types plays a role in gene regulation.

A Comparative View on Molecular Alterations and Potential Therapeutic Strategies for Canine Oral Melanoma

Canine oral melanoma (COM) is a highly aggressive tumour associated with poor prognosis due to metastasis and resistance to conventional anti-cancer therapies. As with human mucosal melanoma, the mutational landscape is predominated by copy number aberrations and chromosomal structural variants, but differences in study cohorts and/or tumour heterogeneity can lead to discordant results regarding the nature of specific genes affected. This review discusses somatic molecular alterations in COM that result from single nucleotide variations, copy number changes, chromosomal rearrangements, and/or dysregulation of small non-coding RNAs. A cross-species comparison highlights notable recurrent aberrations, and functionally grouping dysregulated proteins reveals unifying biological pathways that may be critical for oncogenesis and metastasis. Finally, potential therapeutic strategies are considered to target these pathways in canine patients, and the benefits of collaboration between science, medical, and veterinary communities are emphasised.

Redox regulation of DUBs and its therapeutic implications in cancer

Reactive oxygen species (ROS) act as a double-edged sword in cancer, where low levels of ROS are beneficial but excessive accumulation leads to cancer progression. Elevated levels of ROS in cancer are counteracted by the antioxidant defense system. An imbalance between ROS generation and the antioxidant system alters gene expression and cellular signaling, leading to cancer progression or death. Post-translational modifications, such as ubiquitination, phosphorylation, and SUMOylation, play a critical role in the maintenance of ROS homeostasis by controlling ROS production and clearance. Recent evidence suggests that deubiquitinating enzymes (DUBs)-mediated ubiquitin removal from substrates is regulated by ROS. ROS-mediated oxidation of the catalytic cysteine (Cys) of DUBs, leading to their reversible inactivation, has emerged as a key mechanism regulating DUB-controlled cellular events. A better understanding of the mechanism by which DUBs are susceptible to ROS and exploring the ways to utilize ROS to pharmacologically modulate DUB-mediated signaling pathways might provide new insight for anticancer therapeutics. This review assesses the recent findings regarding ROS-mediated signaling in cancers, emphasizes DUB regulation by oxidation, highlights the relevant recent findings, and proposes directions of future research based on the ROS-induced modifications of DUB activity.

Mitochondrial Metabolism in Melanoma

Melanoma and its associated alterations in cellular pathways have been growing areas of interest in research, especially as specific biological pathways are being elucidated. Some of these alterations include changes in the mitochondrial metabolism in melanoma. Many mitochondrial metabolic changes lead to differences in the survivability of cancer cells and confer resistance to targeted therapies. While extensive work has gone into characterizing mechanisms of resistance, the role of mitochondrial adaptation as a mode of resistance is not completely understood. In this review, we wish to explore mitochondrial metabolism in melanoma and how it impacts modes of resistance. There are several genes that play a major role in melanoma mitochondrial metabolism which require a full understanding to optimally target melanoma. These include BRAF, CRAF, SOX2, MCL1, TRAP1, RHOA, SRF, SIRT3, PTEN, and AKT1. We will be discussing the role of these genes in melanoma in greater detail. An enhanced understanding of mitochondrial metabolism and these modes of resistance may result in novel combinatorial and sequential therapies that may lead to greater therapeutic benefit.

Genetic and Genomic Pathways of Melanoma Development, Invasion and Metastasis

Melanoma is a serious form of skin cancer that accounts for 80% of skin cancer deaths. Recent studies have suggested that melanoma invasiveness is attributed to phenotype switching, which is a reversible type of cell behaviour with similarities to epithelial to mesenchymal transition. Phenotype switching in melanoma is reported to be independent of genetic alterations, whereas changes in gene transcription, and epigenetic alterations have been associated with invasiveness in melanoma cell lines. Here, we review mutational, transcriptional, and epigenomic alterations that contribute to tumour heterogeneity in melanoma, and their potential to drive melanoma invasion and metastasis. We also discuss three models that are hypothesized to contribute towards aspects of tumour heterogeneity and tumour progression in melanoma, namely the clonal evolution model, the cancer stem cell model, and the phenotype switching model. We discuss the merits and disadvantages of each model in explaining tumour heterogeneity in melanoma, as a precursor to invasion and metastasis.

Canonical Signaling Pathways in Melanoma

Melanoma is the most lethal type of skin cancer, originating from the uncontrolled proliferation of melanocytes. The transformation of normal melanocytes into malignant tumor cells has been a focus of research seeking to better understand melanoma's pathogenesis and develop new therapeutic targets. Over the past few decades, a conglomeration of studies has pinpointed several driver mutations and their associated signaling pathways. In this review, we summarize the key signaling pathways and the driver mutations involved in melanoma tumorigenesis and also discuss the potential underlying mechanisms.

Genetic Relationship Between Endometriosis and Melanoma

Epidemiological studies have observed that risk of endometriosis is associated with history of cutaneous melanoma and vice versa. Evidence for shared biological mechanisms between the two traits is limited. The aim of this study was to investigate the genetic correlation and causal relationship between endometriosis and melanoma. Summary statistics from genome-wide association meta-analyses (GWAS) for endometriosis and melanoma were used to estimate the genetic correlation between the traits and Mendelian randomization was used to test for a causal association. When using summary statistics from separate female and male melanoma cohorts we identified a significant positive genetic correlation between melanoma in females and endometriosis (rg = 0.144, se = 0.065, p = 0.025). However, we find no evidence of a correlation between endometriosis and melanoma in males or a combined melanoma dataset. Endometriosis was not genetically correlated with skin color, red hair, childhood sunburn occasions, ease of skin tanning, or nevus count suggesting that the correlation between endometriosis and melanoma in females is unlikely to be influenced by pigmentary traits. Mendelian Randomization analyses also provided evidence for a relationship between the genetic risk of melanoma in females and endometriosis. Colocalization analysis identified 27 genomic loci jointly associated with the two diseases regions that contain different causal variants influencing each trait independently. This study provides evidence of a small genetic correlation and relationship between the genetic risk of melanoma in females and endometriosis. Genetic risk does not equate to disease occurrence and differences in the pathogenesis and age of onset of both diseases means it is unlikely that occurrence of melanoma causes endometriosis. This study instead provides evidence that having an increased genetic risk for melanoma in females is related to increased risk of endometriosis. Larger GWAS studies with increased power will be required to further investigate these associations.

Mucosal Melanoma: Pathological Evolution, Pathway Dependency and Targeted Therapy

Mucosal melanoma (MM) is a rare melanoma subtype that originates from melanocytes within sun-protected mucous membranes. Compared with cutaneous melanoma (CM), MM has worse prognosis and lacks effective treatment options. Moreover, the endogenous or exogenous risk factors that influence mucosal melanocyte transformation, as well as the identity of MM precursor lesions, are ambiguous. Consequently, there remains a lack of molecular markers that can be used for early diagnosis, and therefore better management, of MM. In this review, we first summarize the main functions of mucosal melanocytes. Then, using oral mucosal melanoma (OMM) as a model, we discuss the distinct pathologic stages from benign mucosal melanocytes to metastatic MM, mapping the possible evolutionary trajectories that correspond to MM initiation and progression. We highlight key areas of ambiguity during the genetic evolution of MM from its benign lesions, and the resolution of which could aid in the discovery of new biomarkers for MM detection and diagnosis. We outline the key pathways that are altered in MM, including the MAPK pathway, the PI3K/AKT pathway, cell cycle regulation, telomere maintenance, and the RNA maturation process, and discuss targeted therapy strategies for MM currently in use or under investigation.

PERK mediates resistance to BRAF inhibition in melanoma with impaired PTEN

Targeting mutant BRAF in patients with melanomas harboring this oncogene has been highly successful as a first-line treatment, but other mutations may affect its efficacy and alter the route of acquired resistance resulting in recurrence and poor prognosis. As an evolving strategy, melanoma treatment needs to be expanded to include targets based on newly discovered emerging molecules and pathways. We here show that PERK plays a critical role in BRAF inhibitor-acquired resistance in melanoma with impaired PTEN. Inhibition of PERK by either shRNA or a pharmacological inhibitor blocked the growth of BRAF inhibitor-resistant melanoma with impaired PTEN in vitro and in vivo, suggesting an effective approach against melanomas with mutant BRAF and PTEN deficiency. Our current findings, along with our previous discovery that the AXL/AKT axis mediates resistance to BRAF inhibition in melanoma with wild-type PTEN, provide new insights toward a strategy for combating BRAF inhibition-acquired resistance in BRAF mutant melanoma with different PTEN statuses.

DUXAP8 knockdown inhibits the development of melanoma by regulating the miR-3182/NUPR1 pathway

Double homeobox A pseudogene 8 (DUXAP8) has been reported to regulate the growth of several types of cancers, such as breast cancer and ovarian cancer. However, its role in melanoma remains unclear. In the present study, the mechanism through which DUXAP8 regulates melanoma progression was explored. The expression levels of DUXAP8 were determined in 43 samples from patients with melanoma in different stages, as well as human epidermal melanocytes cells and malignant melanoma cell lines using reverse transcription-quantitative PCR (RT-qPCR). The prognosis of patients was analyzed using the Kaplan-Meier method. The relationship between lncRNA DUXAP8 expression and microRNA (miR)-3182 or nuclear protein 1 transcriptional regulator (NUPR1) levels was analyzed using Pearson's correlation. Luciferase reporter and RNA pull-down were used to examine the interactions between these molecules. Proliferation was assessed using Cell Counting-Kit-8. Transwell assays were used to examine cell migration and invasion. lncRNA DUXAP8 was upregulated in melanoma tissue and cells compared with normal tissues and cells. The levels of DUXAP8 inversely correlated with survival time of patients with melanoma. Knockdown of lncRNA DUXAP8 inhibited proliferation, migration and invasion of melanoma cells. lncRNA DUXAP8 targeted miR-3182, while miR-3182 targeted NUPR1. The overexpression of NUPR1 reversed the effects of DUXAP8 knockdown or miR-3182 mimic on melanoma progression. In conclusion, lncRNA DUXAP8 downregulation inhibits the development of melanoma by regulating the miR-3182/NUPR1 axis.

Combinatorial Therapies to Overcome BRAF/MEK Inhibitors Resistance in Melanoma Cells: An in vitro Study

BACKGROUND

Melanoma accounts for only 1% of all skin malignant tumors; however, it is the deadliest form of skin cancer. Since 2011, FDA (Food and Drug Administration) approved several novel therapeutic strategies, such as MAPK pathway targeted therapies, to treat cutaneous melanoma patients. However, their improvements in overall survival were limited, due to the development of resistance.

METHODS

In this work, several combinations of therapies, including the metabolic modulator DCA, were tested in melanoma cell lines, considering that MAPK and PI3K/AKT/mTOR pathways are deregulated and interconnected in melanoma and that the presence of the Warburg effect in melanoma cells may influence the response to therapy. The effect of the treatments was assessed in the proliferation and survival of melanoma cell lines with different genetic profiles. Also, the possibility to overcome resistance to the treatment with vemurafenib was tested.

RESULTS

In general, higher decrease in cell viability and cell proliferation and increase in apoptosis were obtained after the combination treatments, comparing with single treatments, in all the studied cell lines. The combination of cobimetinib and everolimus appear to be the best treatment option. The BRAFV600E -vemurafenib resistant melanoma cell line showed to retain sensitivity to both everolimus and DCA.

DISCUSSION AND CONCLUSION

Our results suggest that the combination of MAPK pathway inhibitors with mTOR pathway inhibitors and DCA should be considered as therapeutic options to treat melanoma patients, as the combinations potentiated the effects of each drug alone. In a cell line resistant to vemurafenib, we verified that combined MAPK inhibitors with inhibition of mTOR pathway and/or DCA metabolism modulation might constitute possible strategies in order to overcome resistance to MAPK inhibition.

The PI3K/Akt Pathway: Emerging Roles in Skin Homeostasis and a Group of Non-Malignant Skin Disorders

The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway regulates cell proliferation, differentiation, and migration, along with angiogenesis and metabolism. Additionally, it could mediate skin development and homeostasis. There is much evidence to suggest that dysregulation of PI3K/Akt pathway is frequently associated with several human cutaneous malignancies like malignant melanoma (MM), basal cell carcinoma (BCC), and cutaneous squamous cell carcinoma (SCC), as well as their poor outcomes. Nevertheless, emerging roles of PI3K/Akt pathway cascade in a group of common non-malignant skin disorders including acne and psoriasis, among others, have been recognized. The enhanced understanding of dysfunction of PI3K/Akt pathway in patients with these non-malignant disorders has offered a solid foundation for the progress of updated therapeutic targets. This article reviews the latest advances in the roles of PI3K/Akt pathway and their targets in the skin homeostasis and progression of a wide range of non-malignant skin disorders and describes the current progress in preclinical and clinical researches on the involvement of PI3K/Akt pathway targeted therapies.

Oxidative Stress in Cancer Cell Metabolism

Reactive oxygen species (ROS) are important in regulating normal cellular processes whereas deregulated ROS leads to the development of a diseased state in humans including cancers. Several studies have been found to be marked with increased ROS production which activates pro-tumorigenic signaling, enhances cell survival and proliferation and drives DNA damage and genetic instability. However, higher ROS levels have been found to promote anti-tumorigenic signaling by initiating oxidative stress-induced tumor cell death. Tumor cells develop a mechanism where they adjust to the high ROS by expressing elevated levels of antioxidant proteins to detoxify them while maintaining pro-tumorigenic signaling and resistance to apoptosis. Therefore, ROS manipulation can be a potential target for cancer therapies as cancer cells present an altered redox balance in comparison to their normal counterparts. In this review, we aim to provide an overview of the generation and sources of ROS within tumor cells, ROS-associated signaling pathways, their regulation by antioxidant defense systems, as well as the effect of elevated ROS production in tumor progression. It will provide an insight into how pro- and anti-tumorigenic ROS signaling pathways could be manipulated during the treatment of cancer.

SPAG6-silencing enhances decitabine-induced apoptosis and demethylation of PTEN in SKM-1 cells and in a xenograft mouse model

Myelodysplastic syndromes (MDS) are a group of malignant diseases that are characterized by disordered hematopoiesis with a high risk of transforming into leukemia. In the present study, SPAG6-knockdown and decitabine (DAC) treatment resulted in a decreased DNA methyltransferases and methyl-CpG-binding domain protein expression. In addition, DAC and LBH589 were shown to promote apoptosis in SKM-1 cells, and SPAG6-knockdown to enhance the pro-apoptotic effect of DAC. DAC could reduce PTEN methylation and increase PTEN expression in SKM-1 cells. SPAG6-knockdown and LBH589 treatment could increase DAC-mediated demethylation of PTEN promoter. Finally, a mouse model was constructed, and an enhanced efficacy of DAC following SPAG6-knockdown was confirmed in vivo. In conclusion, DAC-mediated apoptosis and PTEN promoter demethylation may be synergistically enhanced by SPAG6-silencing. Therefore, in the present study it was indicated that SPAG6 may be a potential target for demethylation therapy in MDS.

BRAF Gene and Melanoma: Back to the Future

As widely acknowledged, 40-50% of all melanoma patients harbour an activating BRAF mutation (mostly BRAF V600E). The identification of the RAS-RAF-MEK-ERK (MAP kinase) signalling pathway and its targeting has represented a valuable milestone for the advanced and, more recently, for the completely resected stage III and IV melanoma therapy management. However, despite progress in BRAF-mutant melanoma treatment, the two different approaches approved so far for metastatic disease, immunotherapy and BRAF+MEK inhibitors, allow a 5-year survival of no more than 60%, and most patients relapse during treatment due to acquired mechanisms of resistance. Deep insight into BRAF gene biology is fundamental to describe the acquired resistance mechanisms (primary and secondary) and to understand the molecular pathways that are now being investigated in preclinical and clinical studies with the aim of improving outcomes in BRAF-mutant patients.

Resistance to Molecularly Targeted Therapies in Melanoma

Malignant melanoma is the most aggressive type of skin cancer with invasive growth patterns. In 2021, 106,110 patients are projected to be diagnosed with melanoma, out of which 7180 are expected to die. Traditional methods like surgery, radiation therapy, and chemotherapy are not effective in the treatment of metastatic and advanced melanoma. Recent approaches to treat melanoma have focused on biomarkers that play significant roles in cell growth, proliferation, migration, and survival. Several FDA-approved molecular targeted therapies such as tyrosine kinase inhibitors (TKIs) have been developed against genetic biomarkers whose overexpression is implicated in tumorigenesis. The use of targeted therapies as an alternative or supplement to immunotherapy has revolutionized the management of metastatic melanoma. Although this treatment strategy is more efficacious and less toxic in comparison to traditional therapies, targeted therapies are less effective after prolonged treatment due to acquired resistance caused by mutations and activation of alternative mechanisms in melanoma tumors. Recent studies focus on understanding the mechanisms of acquired resistance to these current therapies. Further research is needed for the development of better approaches to improve prognosis in melanoma patients. In this article, various melanoma biomarkers including BRAF, MEK, RAS, c-KIT, VEGFR, c-MET and PI3K are described, and their potential mechanisms for drug resistance are discussed.

Oxidative Stress in the Tumor Microenvironment and Its Relevance to Cancer Immunotherapy

Simple Summary

Cancer cells are consistently under oxidative stress, as reflected by elevated basal level of reactive oxygen species (ROS), due to increased metabolism driven by aberrant cell growth. This feature has been exploited to develop therapeutic strategies that control tumor growth by modulating the oxidative stress in tumor cells. This review provides an overview of recent advances in cancer therapies targeting tumor oxidative stress, and highlights the emerging evidence implicating the effectiveness of cancer immunotherapies in intensifying tumor oxidative stress. The promises and challenges of combining ROS-inducing agents with cancer immunotherapy are also discussed.

Abstract

It has been well-established that cancer cells are under constant oxidative stress, as reflected by elevated basal level of reactive oxygen species (ROS), due to increased metabolism driven by aberrant cell growth. Cancer cells can adapt to maintain redox homeostasis through a variety of mechanisms. The prevalent perception about ROS is that they are one of the key drivers promoting tumor initiation, progression, metastasis, and drug resistance. Based on this notion, numerous antioxidants that aim to mitigate tumor oxidative stress have been tested for cancer prevention or treatment, although the effectiveness of this strategy has yet to be established. In recent years, it has been increasingly appreciated that ROS have a complex, multifaceted role in the tumor microenvironment (TME), and that tumor redox can be targeted to amplify oxidative stress inside the tumor to cause tumor destruction. Accumulating evidence indicates that cancer immunotherapies can alter tumor redox to intensify tumor oxidative stress, resulting in ROS-dependent tumor rejection. Herein we review the recent progresses regarding the impact of ROS on cancer cells and various immune cells in the TME, and discuss the emerging ROS-modulating strategies that can be used in combination with cancer immunotherapies to achieve enhanced antitumor effects.

Novel insights into the pathogenesis and treatment of NRAS mutant melanoma

INTRODUCTION

NRAS was the first mutated oncogene identified in melanoma and is currently the second most common driver mutation in this malignancy. For patients with NRAS^mutant advanced stage melanoma refractory to immunotherapy or with contraindications to immune-based regimens, there are few therapeutic options including low-efficacy chemotherapy regimens and binimetinib monotherapy. Here, we review recent advances in preclinical studies of molecular targets for NRAS mutant melanoma as well as the failures and successes of early-phase clinical trials. While there are no targeted therapies for NRAS-driven melanoma, there is great promise in approaches combining MEK inhibition with inhibitors of the focal adhesion kinase (FAK), inhibitors of autophagy pathways, and pan-RAF inhibitors.

AREAS COVERED

This review surveys new developments in all aspects of disease pathogenesis and potential treatment - including those that have failed, stalled, or progressed through various phases of preclinical and clinical development.

EXPERT OPINION

There are no currently approved targeted therapies for BRAF wild-type melanoma patients harboring NRAS driver mutations though an array of agents are in early phase clinical trials. The diverse strategies taken exploit combined MAP kinase signaling blockade with inhibition of cell cycle mediators, inhibition of the autophagy pathway, and alteration of kinases involved in actin cytoskeleton signaling. Future advances of developmental therapeutics into late stage trials may yield new options beyond immunotherapy for patients with advanced stage disease and NRAS mutation status.

Characterization of a new human astrocytoma cell line SHG140: cell proliferation, cell phenotype, karyotype, STR markers and tumorigenicity analysis

Background: Primary tumor Cell was an important tool for tumor research. Here, a new astrocytoma cell line SHG-140 was established and its proliferation, phenotype, karyotype, STR authentication, pathological characteristics, and characteristics of the cells' intrancranial xenografts of nude mice were studied.

Methods: Primary SHG-140 culture was performed in DMEM/F12 medium with 10% FBS. Cell proliferation, karyotype analysis, cell immunofluorescence and STR authentication of SHG140 cells were performed. HE staining and immunohistochemistry, Whole oncogene high flux sequencing of the patient sample were carried out. SHG140 cells were injected into the brain of nude mice, HE staining and immunohistochemistry of intracranial xenograft tumor were detected.

Results: Cell immunofluorescence demonstrated that SHG140 cells were positive for A2B5 (Glial precursors ganglioside), GFAP (Glial fibrillary acidic protein), Nestin, S-100 (Acid calcium bingding protein), Olig2 (Oligodendrocyte transcription factor 2) and Ki67 (Nuclear-associated antigen), cells negatively stained for Vimentin. Cell proliferation curve revealed that SHG140 proliferated slightly within 48 h, which then significantly proliferated to the fourth day. Karyotype analysis demonstrated its total number of chromosomes was 55, having trisomy of chromosome 6, 7, 8, 9 and X, and tetrad of chromosome 1 and 21, chromosomal deletion and rearrangement were observed. STR markers analysis showed the cells were derived from human male. SHG140 cells had tumorigenic properties - the intracranial injection of these cells into nude mice gave rise to growing tumors. We found that the glioma tissue was diffusively positive for GFAP, Nestin, slightly positive for Olig2, S-100; the positive rate of Ki-67 was 65% and negative for Vimentin. SHG140 cells were tumorigenic, GFAP, Nestin, S-100 Olig-2, the proliferation marker Ki-67 were expressed in its intracranial xenograft, Vimentin was negative expressed. Whole oncogene high flux sequencing of the patient tissue showed TP53, PTEN, IDH1 and PTCH1 mutation were existed.

Conclusions: Our study showed that SHG140 was an astrocytoma glioma continuous cell line derived from a human adult male, having a strong tumorigenicity in nude mice, which made it wound be a useful model for the study of human glioblastoma multiforme.

Non-target genetic manipulation induces rhabdomyosarcoma in KrasPten-driven mouse model of ovarian cancer

Background

Genetically engineered mice are ideal models to advance our understanding the tumorigenesis of ovarian cancer. Our original objective was to establish an ovarian cancer model induced by Kras activation and Pten deletion. However, proficiently establishing the model remains a technical problem, which limits its application.

Methods

We established the Kras activation/Pten deletion-induced mouse model of ovarian cancer by injecting Cre recombinase-expressing adenovirus in the ovarian bursa. PCR analysis, Western blotting, and immunohistochemistry staining were performed to verify the alteration of conditional genes. We detected expression of canonical molecular markers in order to examine the origin of the tumors.

Results

Subcutaneous lumps developed accidentally in mice with ovarian cancer, as early as 2 weeks post in vivo genetic manipulation, far before the destructive growth of ovarian cancer. PCR analysis confirmed the efficient Cre-mediated recombination of Kras and Pten in tumor tissues, which are consistent with the activation of the MAPK and PI3K/Akt/mTOR pathways. Histomorphological and histological analysis showed that the lumps were actually rhabdomyosarcoma (RMS). We confirmed that the leakage of adenovirus transformed healthy adjacent tissues into RMS.

Conclusions

Avoiding accidental exposure of non-target tissues to adenovirus is crucial to successfully establish the ovarian cancer mouse model. Moreover, non-specific genetic manipulations can induce the development of RMS.

Menthol in electronic cigarettes: A contributor to respiratory disease?

Menthol is widely used in tobacco products. This study compared the effects of menthol on human bronchial epithelium using submerged cultures, a VITROCELL® cloud chamber that provides air liquid interface (ALI) exposure without solvents or heating, and a Cultex ALI system that delivers aerosol equivalent to that inhaled during vaping. In submerged culture, menthol significantly increased calcium influx and mitochondrial reactive oxygen species (ROS) via the TRPM8 receptor, responses that were inhibited by a TRPM8 antagonist. VITROCELL® cloud chamber exposure of BEAS-2B monolayers increased mitochondrial protein oxidation, expression of the antioxidant enzyme SOD2, activation of NF-κB, and secretion of inflammatory cytokines (IL-6 and IL-8). Proteomics data collected following ALI exposure of 3D EpiAirway tissue in the Cultex showed upregulation of NRF-2-mediated oxidative stress, oxidative phosphorylation, and IL-8 signaling. Across the three platforms, menthol adversely effected human bronchial epithelium in a manner that could lead to respiratory disease.