Metabolic Profiling to Assess Response to Targeted and Immune Therapy in Melanoma

There is currently no consensus to determine which advanced melanoma patients will benefit from targeted therapy, immunotherapy, or a combination of both, highlighting the critical need to identify early-response biomarkers to advanced melanoma therapy. The goal of this review is to provide scientific rationale to highlight the potential role of metabolic imaging to assess response to targeted and/or immune therapy in melanoma cancer. For that purpose, a brief overview of current melanoma treatments is provided. Then, current knowledge with respect to melanoma metabolism is described with an emphasis on major crosstalks between melanoma cell metabolism and signaling pathways involved in BRAF-targeted therapy as well as in immune checkpoint inhibition therapies. Finally, preclinical and clinical studies using metabolic imaging and/or profiling to assess response to melanoma treatment are summarized with a particular focus on PET (Positron Emission Tomography) imaging and 13C-MRS (Magnetic Resonance Spectroscopy) methods.

Redrawing Urokinase Receptor (uPAR) Signaling with Cancer Driver Genes for Exploring Possible Anti-Cancer Targets and Drugs

During tumorigenesis, urokinase (uPA) and uPA receptor (uPAR) play essential roles in mediating pathological progression in many cancers. To understand the crosstalk between the uPA/uPAR signaling and cancer, as well as to decipher their cellular pathways, we proposed to use cancer driver genes to map out the uPAR signaling. In the study, an integrated pharmaceutical bioinformatics approach that combined modulator identification, driver gene ontology networking, protein targets prediction and networking, pathway analysis and uPAR modulator screening platform construction was employed to uncover druggable targets in uPAR signaling for developing a novel anti-cancer modality. Through these works, we found that uPAR signaling interacted with 10 of 21 KEGG cancer pathways, indicating the important role of uPAR in mediating intracellular cancerous signaling. Furthermore, we verified that receptor tyrosine kinases (RTKs) and ribosomal S6 kinases (RSKs) could serve as signal hubs to relay uPAR-mediated cellular functions on cancer hallmarks such as angiogenesis, proliferation, migration and metastasis. Moreover, we established an in silico virtual screening platform and a uPAR-driver gene pair rule for identifying potential uPAR modulators to combat cancer. Altogether, our results not only elucidated the complex networking between uPAR modulation and cancer but also provided a paved way for developing new chemical entities and/or re-positioning clinically used drugs against cancer.

BRAF Mutations in Melanoma: Biological Aspects, Therapeutic Implications, and Circulating Biomarkers

Melanoma is an aggressive form of skin cancer resulting from the malignant transformation of melanocytes. Recent therapeutic approaches, including targeted therapy and immunotherapy, have improved the prognosis and outcome of melanoma patients. BRAF is one of the most frequently mutated oncogenes recognised in melanoma. The most frequent oncogenic BRAF mutations consist of a single point mutation at codon 600 (mostly V600E) that leads to constitutive activation of the BRAF/MEK/ERK (MAPK) signalling pathway. Therefore, mutated BRAF has become a useful target for molecular therapy and the use of BRAF kinase inhibitors has shown promising results. However, several resistance mechanisms invariably develop leading to therapeutic failure. The aim of this manuscript is to review the role of BRAF mutational status in the pathogenesis of melanoma and its impact on differentiation and inflammation. Moreover, this review focuses on the mechanisms responsible for resistance to targeted therapies in BRAF-mutated melanoma and provides an overview of circulating biomarkers including circulating tumour cells, circulating tumour DNA, and non-coding RNAs.

The extracellular vesicles targeting tumor microenvironment: a promising therapeutic strategy for melanoma

Extracellular vesicles (EVs) are small particles secreted by numerous cell types and circulate in almost all body fluids, acting as crucial messengers for cell-to-cell communication. EVs involves multiple physiological and pathological processes, including tumor progression, via their multiple cargoes. Therefore, EVs have become attractive candidates for the treatment of tumor, including melanoma. Notably, due to the crucial role of the tumor microenvironment (TME) in promoting tumor malignant phenotype, and the close intercellular communication in TME, EVs-based therapy by targeting TME has become a cutting-edge and prospective strategy for inhibiting melanoma progression and strengthening the anti-tumor immunity. In this review, we aimed to summarize and discuss the role of therapeutic EVs, which target the components of TME in melanoma, thereby providing insights into these promising clinical strategies for the treatment of melanoma patients.

Diversity and heterogeneity in human breast cancer adipose tissue revealed at single-nucleus resolution

Introduction

There is increasing awareness of the role of adipose tissue in breast cancer occurrence and development, but no comparison of adipose adjacent to breast cancer tissues and adipose adjacent to normal breast tissues has been reported.

Methods

Single-nucleus RNA sequencing (snRNA-seq) was used to analyze cancer-adjacent and normal adipose tissues from the same breast cancer patient to characterize heterogeneity. SnRNA-seq was performed on 54513 cells from six samples of normal breast adipose tissue (N) distant from the tumor and tumor-adjacent adipose tissue (T) from the three patients (all surgically resected).

Results and discussion

Significant diversity was detected in cell subgroups, differentiation status and, gene expression profiles. Breast cancer induces inflammatory gene profiles in most adipose cell types, such as macrophages, endothelial cells, and adipocytes. Furthermore, breast cancer decreased lipid uptake and the lipolytic phenotype and caused a switch to lipid biosynthesis and an inflammatory state in adipocytes. The in vivo trajectory of adipogenesis revealed distinct transcriptional stages. Breast cancer induced reprogramming across many cell types in breast cancer adipose tissues. Cellular remodeling was investigated by alterations in cell proportions, transcriptional profiles and cell-cell interactions. Breast cancer biology and novel biomarkers and therapy targets may be exposed.

Metabolism heterogeneity in melanoma fuels deactivation of immunotherapy: Predict before protect

Malignant melanoma is widely acknowledged as the most lethal skin malignancy. The metabolic reprogramming in melanoma leads to alterations in glycolysis and oxidative phosphorylation (OXPHOS), forming a hypoxic, glucose-deficient and acidic tumor microenvironment which inhibits the function of immune cells, resulting in a low response rate to immunotherapy. Therefore, improving the tumor microenvironment by regulating the metabolism can be used to improve the efficacy of immunotherapy. However, the tumor microenvironment (TME) and the metabolism of malignant melanoma are highly heterogeneous. Therefore, understanding and predicting how melanoma regulates metabolism is important to improve the local immune microenvironment of the tumor, and metabolism regulators are expected to increase treatment efficacy in combination with immunotherapy. This article reviews the energy metabolism in melanoma and its regulation and prediction, the integration of immunotherapy and metabolism regulators, and provides a comprehensive overview of future research focal points in this field and their potential application in clinical treatment.

The role of angiogenesis in melanoma: Clinical treatments and future expectations

The incidence of melanoma has increased rapidly over the past few decades, with mortality accounting for more than 75% of all skin cancers. The high metastatic potential of Melanoma is an essential factor in its high mortality. Vascular angiogenic system has been proved to be crucial for the metastasis of melanoma. An in-depth understanding of angiogenesis will be of great benefit to melanoma treatment and may promote the development of melanoma therapies. This review summarizes the recent advances and challenges of anti-angiogenic agents, including monoclonal antibodies, tyrosine kinase inhibitors, human recombinant Endostatin, and traditional Chinese herbal medicine. We hope to provide a better understanding of the mechanisms, clinical research progress, and future research directions of melanoma.

Metastatic phenotype and immunosuppressive tumour microenvironment in pancreatic ductal adenocarcinoma: Key role of the urokinase plasminogen activator (PLAU)

Background

Previous studies have revealed the role of dysregulated urokinase plasminogen activator (encoded by PLAU) expression and activity in several pathways associated with cancer progression. However, systematic investigation into the association of PLAU expression with factors that modulate PDAC (pancreatic ductal adenocarcinoma) progression is lacking, such as those affecting stromal (pancreatic stellate cell, PSC)-cancer cell interactions, tumour immunity, PDAC subtypes and clinical outcomes from potential PLAU inhibition.

Methods

This study used an integrated bioinformatics approach to identify prognostic markers correlated with PLAU expression using different transcriptomics, proteomics, and clinical data sets. We then determined the association of dysregulated PLAU and correlated signatures with oncogenic pathways, metastatic phenotypes, stroma, immunosuppressive tumour microenvironment (TME) and clinical outcome. Finally, using an in vivo orthotopic model of pancreatic cancer, we confirmed the predicted effect of inhibiting PLAU on tumour growth and metastasis.

Results

Our analyses revealed that PLAU upregulation is not only associated with numerous other prognostic markers but also associated with the activation of various oncogenic signalling pathways, aggressive phenotypes relevant to PDAC growth and metastasis, such as proliferation, epithelial-mesenchymal transition (EMT), stemness, hypoxia, extracellular cell matrix (ECM) degradation, upregulation of stromal signatures, and immune suppression in the tumour microenvironment (TME). Moreover, the upregulation of PLAU was directly connected with signalling pathways known to mediate PSC-cancer cell interactions. Furthermore, PLAU upregulation was associated with the aggressive basal/squamous phenotype of PDAC and significantly reduced overall survival, indicating that this subset of patients may benefit from therapeutic interventions to inhibit PLAU activity. Our studies with a clinically relevant orthotopic pancreatic model showed that even short-term PLAU inhibition is sufficient to significantly halt tumour growth and, importantly, eliminate visible metastasis.

Conclusion

Elevated PLAU correlates with increased aggressive phenotypes, stromal score, and immune suppression in PDAC. PLAU upregulation is also closely associated with the basal subtype type of PDAC; patients with this subtype are at high risk of mortality from the disease and may benefit from therapeutic targeting of PLAU.

Mapping phenotypic heterogeneity in melanoma onto the epithelial-hybrid-mesenchymal axis

Epithelial to mesenchymal transition (EMT) is a well-studied hallmark of epithelial-like cancers that is characterized by loss of epithelial markers and gain of mesenchymal markers. Melanoma, which is derived from melanocytes of the skin, also undergo phenotypic plasticity toward mesenchymal-like phenotypes under the influence of various micro-environmental cues. Our study connects EMT to the phenomenon of de-differentiation (i.e., transition from proliferative to more invasive phenotypes) observed in melanoma cells during drug treatment. By analyzing 78 publicly available transcriptomic melanoma datasets, we found that de-differentiation in melanoma is accompanied by upregulation of mesenchymal genes, but not necessarily a concomitant loss of an epithelial program, suggesting a more “one-dimensional” EMT that leads to a hybrid epithelial/mesenchymal phenotype. Samples lying in the hybrid epithelial/mesenchymal phenotype also correspond to the intermediate phenotypes in melanoma along the proliferative-invasive axis - neural crest and transitory ones. As melanoma cells progress along the invasive axis, the mesenchymal signature does not increase monotonically. Instead, we observe a peak in mesenchymal scores followed by a decline, as cells further de-differentiate. This biphasic response recapitulates the dynamics of melanocyte development, suggesting close interactions among genes controlling differentiation and mesenchymal programs in melanocytes. Similar trends were noted for metabolic changes often associated with EMT in carcinomas in which progression along mesenchymal axis correlates with the downregulation of oxidative phosphorylation, while largely maintaining glycolytic capacity. Overall, these results provide an explanation for how EMT and de-differentiation axes overlap with respect to their transcriptional and metabolic programs in melanoma.

Comprehensive analysis of the importance of PLAUR in the progression and immune microenvironment of renal clear cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is a common type of kidney cancer with a high mortality rate, and the discovery of new therapeutic markers is essential to improve patient survival. The plasminogen activator urokinase receptor (PLAUR) plays key roles in tissue remodeling and extracellular matrix degradation, which contribute to invasion and metastasis, a major feature of tumor malignancy. The role of PLAUR in ccRCC pathology has not been deeply studied. In this study, we collected the mRNA expression data of 33 tumor types, each derived from human patients obtained from TCGA database, and comprehensively analyzed the correlation between the expression of PLAUR in tumors and prognosis. Then, we studied the relationship between PLAUR expression in ccRCC and specific clinical features of ccRCC patients. In addition, we analyzed the function and mechanism of PLAUR in ccRCC. Our results showed that PLAUR was significantly overexpressed in ccRCC and that both PLAUR levels and PLAUR methylation levels significantly correlated with poor prognosis. Our results also suggest that PLAUR is involved in the progression of ccRCC. The results of functional and mechanistic analysis of PLAUR showed that PLAUR is involved in inflammatory and immune-related pathways in ccRCC; other data showed that PLAUR expression may affect the infiltration of multiple immune cell types in ccRCC and that PLAUR levels were significantly and positively correlated with the expression of immune checkpoints. In conclusion, our findings suggest that high PLAUR expression can promote the progression of ccRCC to poor prognosis, and thus PLAUR may serve as both a potential marker for predicting macrophage infiltration and immune microenvironment status and as an important immunotherapy target for ccRCC.

uPAR: An Essential Factor for Tumor Development

Tumorigenesis is closely related to the loss of control of many genes. Urokinase-type plasminogen activator receptor (uPAR), a glycolipid-anchored protein on the cell surface, is controlled by many factors in tumorigenesis and is expressed in many tumor tissues. In this review, we summarize the regulatory effects of the uPAR signaling pathway on processes and factors related to tumor progression, such as tumor cell proliferation, adhesion, metastasis, glycolysis, tumor microenvironment and angiogenesis. Overall, the evidence accumulated to date suggests that uPAR induction by tumor progression may be one of the most important factors affecting therapeutic efficacy. An improved understanding of the interactions between uPAR and its coreceptors in cancer will provide critical biomolecular information that may help to better predict the disease course and response to therapy.

Claisened Hexafluoro Inhibits Metastatic Spreading of Amoeboid Melanoma Cells

Metastatic melanoma is characterized by poor prognosis and a low free-survival rate. Thanks to their high plasticity, melanoma cells are able to migrate exploiting different cell motility strategies, such as the rounded/amoeboid-type motility and the elongated/mesenchymal-type motility. In particular, the amoeboid motility strongly contributes to the dissemination of highly invasive melanoma cells and no treatment targeting this process is currently available for clinical application. Here, we tested Claisened Hexafluoro as a novel inhibitor of the amoeboid motility. Reported data demonstrate that Claisened Hexafluoro specifically inhibits melanoma cells moving through amoeboid motility by deregulating mitochondrial activity and activating the AMPK signaling. Moreover, Claisened Hexafluoro is able to interfere with the adhesion abilities and the stemness features of melanoma cells, thus decreasing the in vivo metastatic process. This evidence may contribute to pave the way for future possible therapeutic applications of Claisened Hexafluoro to counteract metastatic melanoma dissemination.

The role of Hypoxia-Inducible Factor-1alpha and its signaling in melanoma

Adaptation to the loss of O2 is regulated via the activity of hypoxia-inducible factors such as Hypoxia-Inducible Factor-1 (HIF-1). HIF-1 acts as a main transcriptional mediator in the tissue hypoxia response that regulates over 1000 genes related to low oxygen tension. The role of HIF-1α in oncogenic processes includes angiogenesis, tumor metabolism, cell proliferation, and metastasis, which has been examined in various malignancies, such as melanoma. Melanoma is accompanied by a high death rate and a cancer type whose incidence has risen over the last decades. The linkage between O2 loss and melanogenesis had extensively studied over decades. Recent studies revealed that HIF-1α contributes to melanoma progression via different signaling pathways such as PI3K/Akt/mTOR, RAS/RAF/MEK/ERK, JAK/STAT, Wnt/β-catenin, Notch, and NF-κB. Also, various microRNAs (miRs) are known to mediate the HIF-1α role in melanoma. Therefore, HIF-1α offers a diagnostic/prognostic biomarker and a candidate for targeted therapy in melanoma.

A novel peptide promotes human trophoblast proliferation and migration through PI3K/Akt/mTOR signaling pathway

Background

Preeclampsia (PE) is a complex pregnancy-related disease that endangers the safety of maternal and fetal. The purpose of this study is to reveal the pathogenesis of preeclampsia and discover new predictors from the perspective of peptidomics. The umbilical cord blood of PE and control group was analyzed by peptidomics. A peptide named Regulation of Proliferation Process in Preeclampsia (ROPPIP) was screened out to explore its role in the proliferation, migration and apoptosis of trophoblast cells in preeclampsia.

Methods

We compared and analyzed the umbilical cord blood of patients with PE and normal pregnant women using liquid chromatography-tandem mass spectrometry (LC-MS). hTR-8/Svneo cells cultured in vitro were divided into ROPPIP group and a disordered peptide group as control. Cell Counting Kit-8 (CCK-8) assay, flow cytometry, Transwell chamber assays and western blot analysis were performed to detect cell proliferation, invasion, migration and apoptosis, in addition to the expression of Matrix metalloproteinase-2 (MMP2), nuclear associated antigen Ki67, B-cell lymphoma-2 (Bcl2), Caspase 3, and β-actin protein.

Results

We identified 133 differential peptides. Of these, 51 were up-regulated while 82 were down-regulated. the polypeptide SFGVRMATASPTDGNV with low differential expression in the serum of PE patients was selected for the study, we named the polypeptide as Regulation of Proliferation Process in PE (ROPPIP). The experiment shows that ROPPIP can up-regulate the expression levels of MMP2, Ki67, and Bcl2 in HTR-8/Svneo cells, down-regulate the expression of caspase-3, promote the proliferation and migration of HTR-8/Svneo cells and inhibit the apoptosis induced by cisplatin, the activation of the phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway may be associated with the function of ROPPIP.

Conclusions

ROPPIP promotes HTR-8/Svneo cells migration and proliferation, and inhibits apoptosis, by regulating the activation of the PI3K/AKT/mTOR signaling pathway.

CRISPR/Cas9 uPAR Gene Knockout Results in Tumor Growth Inhibition, EGFR Downregulation and Induction of Stemness Markers in Melanoma and Colon Carcinoma Cell Lines

uPAR is a globular protein, tethered to the cell membrane by a GPI-anchor involved in several cancer-related properties and its overexpression commonly correlates with poor prognosis and metastasis. We investigated the consequences of uPAR irreversible loss in human melanoma and colon cancer cell lines, knocking out its expression by CRISPR/Cas9. We analyzed through flow cytometry, western blotting and qPCR, the modulation of the most known cancer stem cells-associated genes and the EGFR while we observed the proliferation rate exploiting 2D and 3D cellular models. We also generated uPAR “rescue” expression cell lines as well as we promoted the expression of only its 3’UTR to demonstrate the involvement of uPAR mRNA in tumor progression. Knocking out PLAUR, uPAR-encoding gene, we observed an inhibited growth ratio unexpectedly coupled with a significant percentage of cells acquiring a stem-like phenotype. In vivo experiments demonstrated that uPAR loss completely abrogates tumorigenesis despite the gained stem-like profile. Nonetheless, we proved that the reintroduction of the 3’UTR of PLAUR gene was sufficient to restore the wild-type status validating the hypothesis that such a region may act as a “molecular sponge”. In particular miR146a, by binding PLAUR 3’ UTR region might be responsible for uPAR-dependent inhibition of EGFR expression.

uPAR+ extracellular vesicles: a robust biomarker of resistance to checkpoint inhibitor immunotherapy in metastatic melanoma patients

Background

Emerging evidence has highlighted the importance of extracellular vesicle (EV)-based biomarkers of resistance to immunotherapy with checkpoint inhibitors in metastatic melanoma. Considering the tumor-promoting implications of urokinase-type plasminogen activator receptor (uPAR) signaling, this study aimed to assess uPAR expression in the plasma-derived EVs of patients with metastatic melanoma to determine its potential correlation with clinical outcomes.

Methods

Blood samples from 71 patients with metastatic melanoma were collected before initiating immunotherapy. Tumor-derived and immune cell-derived EVs were isolated and analyzed to assess the relative percentage of uPAR⁺ EVs. The associations between uPAR and clinical outcomes, sex, BRAF status, baseline lactate dehydrogenase levels and number of metastatic sites were assessed.

Results

Responders had a significantly lower percentage of tumor-derived, dendritic cell (DC)-derived and CD8⁺ T cell-derived uPAR +EVs at baseline than non-responders. The Kaplan-Meier survival curves for the uPAR⁺EV quartiles indicated that higher levels of melanoma-derived uPAR⁺ EVs were strongly correlated with poorer progression-free survival (p<0.0001) and overall survival (p<0.0001). We also found a statistically significant correlation between lower levels of uPAR⁺ EVs from both CD8⁺ T cells and DCs and better survival.

Conclusions

Our results indicate that higher levels of tumor-derived, DC-derived and CD8⁺ T cell-derived uPAR⁺ EVs in non-responders may represent a new biomarker of innate resistance to immunotherapy with checkpoint inhibitors. Moreover, uPAR⁺ EVs represent a new potential target for future therapeutic approaches.

The Urokinase Receptor: A Multifunctional Receptor in Cancer Cell Biology. Therapeutic Implications

Proteolysis is a key event in several biological processes; proteolysis must be tightly controlled because its improper activation leads to dramatic consequences. Deregulation of proteolytic activity characterizes many pathological conditions, including cancer. The plasminogen activation (PA) system plays a key role in cancer; it includes the serine-protease urokinase-type plasminogen activator (uPA). uPA binds to a specific cellular receptor (uPAR), which concentrates proteolytic activity at the cell surface, thus supporting cell migration. However, a large body of evidence clearly showed uPAR involvement in the biology of cancer cell independently of the proteolytic activity of its ligand. In this review we will first describe this multifunctional molecule and then we will discuss how uPAR can sustain most of cancer hallmarks, which represent the biological capabilities acquired during the multistep cancer development. Finally, we will illustrate the main data available in the literature on uPAR as a cancer biomarker and a molecular target in anti-cancer therapy.

Anti-angiogenic effects of mangiferin and mechanism of action in metastatic melanoma

Advanced metastatic melanoma, one of the most aggressive skin malignancies, is currently without reliable therapy. The process of angiogenesis is crucial for progression and metastasis of the majority of solid tumors including melanomas. Therefore, new therapies are urgently needed. Mangiferin is a naturally occurring glucosylxanthone which exerts many pharmacological activities against cancer-inflammation. However, the effect of mangiferin on metastasis and tumor growth of metastatic melanoma remains unclear. In this study, we demonstrate that mangiferin interferes with inflammation, lipid and calcium signaling which selectively inhibits multiple NFkB target genes including interleukin-6, tumor necrosis factor, interferon gamma, vascular endothelial growth factor receptor 2, plasminogen activator urokinase, matrix metalloprotease 19, C-C Motif Chemokine Ligand 2 and placental growth factor. This abrogates angiogenic and invasive processes and capillary tube formation of metastatic melanoma cells as well as human placental blood vessel explants in-vitro and blocks angiogenesis characteristic of the chicken egg chorioallantoic membrane assay and in melanoma syngeneic studies in vivo. The results obtained in this research illustrate promising anti-angiogenic effects of the natural glucosylxanthone mangiferin for further (pre)clinical studies in melanoma cancer patients.

A potentiated cooperation of carbonic anhydrase IX and histone deacetylase inhibitors against cancer

The emergence of tumour recurrence and resistance limits the survival rate for most tumour-bearing patients. Only, combination therapies targeting pathways involved in the induction and in the maintenance of cancer growth and progression might potentially result in an enhanced therapeutic efficacy. Herein, we provided a prospective combination treatment that includes suberoylanilide hydroxamic acid (SAHA), a well-known inhibitor of histone deacetylases (HDACs), and SLC-0111, a novel inhibitor of carbonic anhydrase (CA) IX. We proved that HDAC inhibition with SAHA in combination with SLC-0111 affects cell viability and colony forming capability to greater extent than either treatment alone of breast, colorectal and melanoma cancer cells. At the molecular level, this therapeutic regimen resulted in a synergistically increase of histone H4 and p53 acetylation in all tested cell lines. Overall, our findings showed that SAHA and SLC-0111 can be regarded as very attractive combination providing a potential therapeutic strategy against different cancer models.

uPAR-expressing melanoma exosomes promote angiogenesis by VE-Cadherin, EGFR and uPAR overexpression and rise of ERK1,2 signaling in endothelial cells

Exosomes (Exos) have been reported to promote pre-metastatic niche formation, proliferation, angiogenesis and metastasis. We have investigated the role of uPAR in melanoma cell lines-derived Exos and their pro-angiogenic effects on human microvascular endothelial cells (HMVECs) and endothelial colony-forming cells (ECFCs). Melanoma Exos were isolated from conditioned media of A375 and M6 cells by differential centrifugation and filtration. Tunable Resistive Pulse Sensing (TRPS) and Nanoparticle tracking analysis were performed to analyze dimension and concentration of Exos. The CRISPR–Cas 9 technology was exploited to obtain a robust uPAR knockout. uPAR is expressed in melanoma Exos that are internalized by HMVECs and ECFCs, enhancing VE-Cadherin, EGFR and uPAR expression in endothelial cells that undergo a complete angiogenic program, including proliferation, migration and tube formation. uPAR loss reduced the pro-angiogenic effects of melanoma Exos in vitro and in vivo by inhibition of VE-Cadherin, EGFR and uPAR expression and of ERK1,2 signaling in endothelial cells. A similar effect was obtained with a peptide that inhibits uPAR–EGFR interaction and with the EGFR inhibitor Gefitinib, which also inhibited melanoma Exos-dependent EGFR phosphorylation. This study suggests that uPAR is required for the pro-angiogenic activity of melanoma Exos. We propose the identification of uPAR-expressing Exos as a potentially useful biomarker for assessing pro-angiogenic propensity and eventually monitoring the response to treatment in metastatic melanoma patients.

Tumor Suppressor Role of hsa-miR-193a-3p and -5p in Cutaneous Melanoma

BACKGROUND

Remarkable deregulation of several microRNAs (miRNAs) is demonstrated in cutaneous melanoma. hsa-miR-193a-3p is reported to be under-expressed in tissues and in plasma of melanoma patients, but the role of both miR-193a arms in melanoma is not known yet.

METHODS

After observing the reduced levels of miR-193a arms in plasma exosomes of melanoma patients, the effects of hsa-miR-193a-3p and -5p transfection in cutaneous melanoma cell lines are investigated.

RESULTS

In melanoma cell lines A375, 501Mel, and MeWo, the ectopic over-expression of miR-193a arms significantly reduced cell viability as well as the expression of genes involved in proliferation (ERBB2, KRAS, PIK3R3, and MTOR) and apoptosis (MCL1 and NUSAP1). These functional features were accompanied by a significant downregulation of Akt and Erk pathways and a strong increase in the apoptotic process. Since in silico databases revealed TROY, an orphan member of the tumor necrosis receptor family, as a potential direct target of miR-193a-5p, this possibility was investigated using the luciferase assay and excluded by our results.

CONCLUSIONS

Our results underline a relevant role of miR-193a, both -3p and -5p, as tumor suppressors clarifying the intracellular mechanisms involved and suggesting that their ectopic over-expression could represent a novel treatment for cutaneous melanoma patients.

Characterization of four subtypes in morphologically normal tissue excised proximal and distal to breast cancer

Widespread mammographic screening programs and improved self-monitoring allow for breast cancer to be detected earlier than ever before. Breast-conserving surgery is a successful treatment for select women. However, up to 40% of women develop local recurrence after surgery despite apparently tumor-free margins. This suggests that morphologically normal breast may harbor early alterations that contribute to increased risk of cancer recurrence. We conducted a comprehensive transcriptomic and proteomic analysis to characterize 57 fresh-frozen tissues from breast cancers and matched histologically normal tissues resected proximal to (<2 cm) and distant from (5-10 cm) the primary tumor, using tissues from cosmetic reduction mammoplasties as baseline. Four distinct transcriptomic subtypes are identified within matched normal tissues: metabolic; immune; matrisome/epithelial-mesenchymal transition, and non-coding enriched. Key components of the subtypes are supported by proteomic and tissue composition analyses. We find that the metabolic subtype is associated with poor prognosis (p < 0.001, HR6.1). Examination of genes representing the metabolic signature identifies several genes able to prognosticate outcome from histologically normal tissues. A subset of these have been reported for their predictive ability in cancer but, to the best of our knowledge, these have not been reported altered in matched normal tissues. This study takes an important first step toward characterizing matched normal tissues resected at pre-defined margins from the primary tumor. Unlocking the predictive potential of unexcised tissue could prove key to driving the realization of personalized medicine for breast cancer patients, allowing for more biologically-driven analyses of tissue margins than morphology alone.

Metabolic Plasticity of Melanoma Cells and Their Crosstalk With Tumor Microenvironment

Cutaneous melanoma (CM) is a highly aggressive and drug resistant solid tumor, showing an impressive metabolic plasticity modulated by oncogenic activation. In particular, melanoma cells can generate adenosine triphosphate (ATP) during cancer progression by both cytosolic and mitochondrial compartments, although CM energetic request mostly relies on glycolysis. The upregulation of glycolysis is associated with constitutive activation of BRAF/MAPK signaling sustained by BRAF^V600E kinase mutant. In this scenario, the growth and progression of CM are strongly affected by melanoma metabolic changes and interplay with tumor microenvironment (TME) that sustain tumor development and immune escape. Furthermore, CM metabolic plasticity can induce a metabolic adaptive response to BRAF/MEK inhibitors (BRAFi/MEKi), associated with the shift from glycolysis toward oxidative phosphorylation (OXPHOS). Therefore, in this review article we survey the metabolic alterations and plasticity of CM, its crosstalk with TME that regulates melanoma progression, drug resistance and immunosurveillance. Finally, we describe hallmarks of melanoma therapeutic strategies targeting the shift from glycolysis toward OXPHOS.

Chronic Resveratrol Treatment Reduces the Pro-angiogenic Effect of Human Fibroblast "Senescent-Associated Secretory Phenotype" on Endothelial Colony-Forming Cells: The Role of IL8

Senescent cells are characterized by an increased secretion of inflammatory and growth factors, known as the "senescence-associated secretory phenotype" (SASP), producing a pro-tumoral and pro-angiogenic microenvironment. This work proposes chronic resveratrol treatment (5 µM for 5 weeks, termed R5) of senescent MRC5 fibroblasts as a mean to mimic and target the angiogenic trait of stromal fibroblast SASP. Senescent fibroblast conditioned medium (CM sen) was effective in enhancing the angiogenic properties of endothelial colony-forming cells (ECFCs), that is, invasive activity and capillary morphogenesis capability in vitro, that were significantly reduced when conditioned media were collected after resveratrol pretreatment (CM senR5). The attenuation of ECFC angiogenic phenotype induced by CM senR5 was accompanied by reduced protein levels of epidermal growth factor and urokinase plasminogen activator receptors (EGFR, uPAR), and by a related decreased activation of receptor-tyrosine-kinase signaling pathways. IL8 levels were found reduced in CM senR5 compared to CM sen, with the associated reduction of IL8-CXCR2 binding in ECFCs. IL8-subtraction mitigated the pro-angiogenic features of CM sen and the associated intracellular signaling in ECFCs, indicating a prominent role of IL8 in the pro-angiogenic effects of CM sen. IL8 modulation is an important mechanism underlying the antiangiogenic activity of resveratrol on MRC5 SASP.

Acidosis and proteolysis in the tumor microenvironment

The glycolytic phenotype of the Warburg effect is associated with acidification of the tumor microenvironment. In this review, we describe how acidification of the tumor microenvironment may increase the invasive and degradative phenotype of cancer cells. As a template of an extracellular acidic microenvironment that is linked to proteolysis, we use the resorptive pit formed between osteoclasts and bone. We describe similar changes that have been observed in cancer cells in response to an acidic microenvironment and that are associated with proteolysis and invasive and metastatic phenotypes. This includes consideration of changes observed in the intracellular trafficking of vesicles, i.e., lysosomes and exosomes, and in specialized regions of the membrane, i.e., invadopodia and caveolae. Cancer-associated cells are known to affect what is generally referred to as tumor proteolysis but little direct evidence for this being regulated by acidosis; we describe potential links that should be verified.

uPAR Knockout Results in a Deep Glycolytic and OXPHOS Reprogramming in Melanoma and Colon Carcinoma Cell Lines

Urokinase Plasminogen Activator (uPA) Receptor (uPAR) is a well-known GPI-anchored three-domain membrane protein with pro-tumor roles largely shown in all the malignant tumors where it is over-expressed. Here we have exploited the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 gene knock out approach to investigate its role in the oxidative metabolism in human melanoma and colon cancer as the consequences of its irreversible loss. Knocking out PLAUR, a uPAR-encoding gene, in A375p, A375M6 and HCT116, which are two human melanoma and a colon carcinoma, respectively, we have observed an increased number of mitochondria in the two melanoma cell lines, while we evidenced an immature biogenesis of mitochondria in the colon carcinoma culture. Such biological diversity is, however, reflected in a significant enhancement of the mitochondrial spare respiratory capacity, fueled by an increased expression of GLS2, and in a decreased glycolysis paired with an increased secretion of lactate by all uPAR KO cells. We speculated that this discrepancy might be explained by an impaired ratio between LDHA and LDHB.

Metabolic flexibility in melanoma: A potential therapeutic target

Cutaneous melanoma (CM) represents one of the most metastasizing and drug resistant solid tumors. CM is characterized by a remarkable metabolic plasticity and an important connection between oncogenic activation and energetic metabolism. In fact, melanoma cells can use both cytosolic and mitochondrial compartments to produce adenosine triphosphate (ATP) during cancer progression. However, the CM energetic demand mainly depends on glycolysis, whose upregulation is strictly linked to constitutive activation of BRAF/MAPK pathway affected by BRAF^V600E kinase mutant. Furthermore, the impressive metabolic plasticity of melanoma allows the development of resistance mechanisms to BRAF/MEK inhibitors (BRAFi/MEKi) and the adaptation to microenvironmental changes. The metabolic interaction between melanoma cells and tumor microenvironment affects the immune response and CM growth. In this review article, we describe the regulation of melanoma metabolic alterations and the metabolic interactions between cancer cells and microenvironment that influence melanoma progression and immune response. Finally, we summarize the hallmarks of melanoma therapies and we report BRAF/MEK pathway targeted therapy and mechanisms of metabolic resistance.

ARHGAP4 mediates the Warburg effect in pancreatic cancer through the mTOR and HIF-1α signaling pathways

Objective

The phenomenon that cancer cells avidly exhibit glycolysis with lactate secretion and decrease in mitochondrial activity under aerobic conditions is known historically as the Warburg effect. Rho GTPase-activating protein 4 (ARHGAP4) is an important negative regulator of the Rho signaling pathway that was associated with the tumorigenesis. Our study aims to determine the function of ARHGAP4 in controlling the glycolytic process of pancreatic cancer in vitro and possible molecular mechanism involved.

Methods

ARHGAP4 and PKM2 expressions in pancreatic cancer tissues were measured by immunohistochemistry. Human pancreatic cancer cells transfected with ARHGAP4 expressing lentivirus or siRNA were treated with either mTOR inhibitor (Rapamycin) or HIF-1α inhibitor (YC-1), and the effects were analyzed on cell viability, glucose uptake, lactate release, and the levels of ARHGAP4, p-mTOR, mTOR, PKM2, and HIF-1α expression.

Results

Our findings showed that ARHGAP4 and PKM2 expressions were, respectively, down-regulated and up-regulated in pancreatic cancer tissues. Overexpression of ARHGAP4 significantly inhibited cell viability, glucose uptake, lactate release, PKM2 expression, and activation of mTOR and HIF-1α signaling pathways in pancreatic cancer cells while ARHGAP4 silencing and treatment of Rapamycin or YC-1 showed inverse effects. Additionally, ARHGAP4 downregulation induced cell morphology of pancreatic cancer was inhibited by Rapamycin or YC-1 treatment.

Conclusion

These findings suggest that mTOR and HIF-1α signaling pathways can regulate the ARHGAP4-mediated glycolytic process of pancreatic cancer.

Dual Effects of Chinese Herbal Medicines on Angiogenesis in Cancer and Ischemic Stroke Treatments: Role of HIF-1 Network

Hypoxia-inducible factor-1 (HIF-1)–induced angiogenesis has been involved in numerous pathological conditions, and it may be harmful or beneficial depending on the types of diseases. Exploration on angiogenesis has sparked hopes in providing novel therapeutic approaches on multiple diseases with high mortality rates, such as cancer and ischemic stroke. The HIF-1 pathway is considered to be a major regulator of angiogenesis. HIF-1 seems to be involved in the vascular formation process by synergistic correlations with other proangiogenic factors in cancer and cerebrovascular disease. The regulation of HIF-1–dependent angiogenesis is related to the modulation of HIF-1 bioactivity by regulating HIF-1α transcription or protein translation, HIF-1α DNA binding, HIF-1α and HIF-1α dimerization, and HIF-1 degradation. Traditional Chinese herbal medicines have a long history of clinical use in both cancer and stroke treatments in Asia. Growing evidence has demonstrated potential proangiogenic benefits of Chinese herbal medicines in ischemic stroke, whereas tumor angiogenesis could be inhibited by the active components in Chinese herbal medicines. The objective of this review is to provide comprehensive insight on the effects of Chinese herbal medicines on angiogenesis by regulating HIF-1 pathways in both cancer and ischemic stroke.

EGFR/uPAR interaction as druggable target to overcome vemurafenib acquired resistance in melanoma cells

Background

BRAF inhibitor (BRAF-I) therapy for melanoma patients harboring the V600E mutation is initially highly effective, but almost all patients relapse within a few months. Understanding the molecular mechanisms behind BRAF-I responsiveness and acquired resistance is therefore an important issue. Here we assessed the role of urokinase type plasminogen activator receptor (uPAR) as a potentially valuable biomarker in the acquisition of BRAF-I resistance in V600E mutant melanoma cells.

Methods

We examined uPAR and EGFR levels by real time PCR and western blot analysis. uPAR loss of function was realized by knocking down uPAR by RNAi or using M25, a peptide that uncouples uPAR-integrin interaction. We investigated uPAR-β1integrin-EGFR association by co-immunoprecipitation and confocal immuno-fluorescence analysis. Acquired resistance to BRAF-I was generated by chronic exposure of cells to vemurafenib.

Findings

We proved that uPAR knockdown in combination with vemurafenib inhibits melanoma cell proliferation to greater extent than either treatment alone causing a decrease in AKT and ERK1/2 phosphorylation. Conversely, we demonstrated that uPAR enforced over-expression results in reduced sensitivity to BRAF inhibition. Moreover, by targeting uPAR and EGFR interaction with an integrin antagonist peptide we restored vemurafenib responsiveness in melanoma resistant cells. Furthermore, we found significant detectable uPAR and EGFR levels in tumor biopsies of 4 relapsed patients.

Interpretation

We disclosed an unpredicted mechanism of reduced sensitiveness to BRAF inhibition, driven by elevated levels of uPAR and identified a potential therapeutic strategy to overcome acquired resistance.

Funds

Associazione Italiana Ricerca sul Cancro (AIRC); Ente Cassa di Risparmio di Firenze.

AKT2 contributes to increase ovarian cancer cell migration and invasion through the AKT2-PKM2-STAT3/NF-κB axis

Multiple studies have shown that protein kinase Bβ (AKT2) is involved in the development and progression of ovarian cancer, however, its precise role remains unclear. Here we explored the underlying molecular mechanisms how AKT2 promotes ovarian cancer progression. We examined the effects of AKT2 in vitro in two ovarian cancer cell lines (SKOV3 and HEY), and in vivo by metastasis assay in nude mice. The migration and invasion ability of SKOV3 and HEY cells was determined by transwell assay. Overexpression and knockdown (with shRNA) experiments were carried out to unravel the underlying signaling mechanisms induced by AKT2. Overexpression of AKT2 led to increased expression of pyruvate kinase (PKM2) in ovarian cancer cells and in lung metastatic foci from nude mice. Elevated AKT2/PKM2 expression induced cell migration and invasion in vitro, as well as lung metastasis in vivo; silencing AKT2 blocked these effects. Meanwhile, PKM2 overexpression was unable to increase AKT2 expression. The expressions of p-PI3K, p-AKT2, and PKM2 were increased when stimulated by epidermal growth factor (EGF); however, these expressions were blocked when inhibited the PI3K by LY294002. STAT3 expression was elevated and NF-κB p65 nuclear translocation was activated both in vitro and in vivo when either AKT2 or PKM2 was overexpressed; and these effects were inhibited when silencing AKT2 expression. Taken together, AKT2 increases the migration and invasion of ovarian cancer cells in vitro and promotes lung metastasis in nude mice in vivo through PKM2-mediated elevation of STAT3 expression and NF-κB activation. In conclusion, we highlight a novel mechanism of the AKT2-PKM2-STAT3/NF-κB axis in the regulation of ovarian cancer progression, and our work suggested that both AKT2 and PKM2 may be potential targets for the treatment of ovarian cancer.

Strategies to Improve the Efficacy of Dendritic Cell-Based Immunotherapy for Melanoma

Melanoma is a highly aggressive form of skin cancer that frequently metastasizes to vital organs, where it is often difficult to treat with traditional therapies such as surgery and radiation. In such cases of metastatic disease, immunotherapy has emerged in recent years as an exciting treatment option for melanoma patients. Despite unprecedented successes with immune therapy in the clinic, many patients still experience disease relapse, and others fail to respond at all, thus highlighting the need to better understand factors that influence the efficacy of antitumor immune responses. At the heart of antitumor immunity are dendritic cells (DCs), an innate population of cells that function as critical regulators of immune tolerance and activation. As such, DCs have the potential to serve as important targets and delivery agents of cancer immunotherapies. Even immunotherapies that do not directly target or employ DCs, such as checkpoint blockade therapy and adoptive cell transfer therapy, are likely to rely on DCs that shape the quality of therapy-associated antitumor immunity. Therefore, understanding factors that regulate the function of tumor-associated DCs is critical for optimizing both current and future immunotherapeutic strategies for treating melanoma. To this end, this review focuses on advances in our understanding of DC function in the context of melanoma, with particular emphasis on (1) the role of immunogenic cell death in eliciting tumor-associated DC activation, (2) immunosuppression of DC function by melanoma-associated factors in the tumor microenvironment, (3) metabolic constraints on the activation of tumor-associated DCs, and (4) the role of the microbiome in shaping the immunogenicity of DCs and the overall quality of anti-melanoma immune responses they mediate. Additionally, this review highlights novel DC-based immunotherapies for melanoma that are emerging from recent progress in each of these areas of investigation, and it discusses current issues and questions that will need to be addressed in future studies aimed at optimizing the function of melanoma-associated DCs and the antitumor immune responses they direct against this cancer.

Transcriptomic pathway analysis of urokinase receptor silenced breast cancer cells: a microarray study

Urokinase plasminogen activator receptor (PLAUR) has been implicated in a variety of physiological and pathological conditions. The multi-functionality of PLAUR is due to its capacity to interact with many co-receptors to regulate extracellular proteolysis and intracellular signaling. Recent reports are identifying novel functions of PLAUR which were not evident in the past; however, the molecular mechanisms of PLAUR signaling are not completely understood. Here, we have compared the transcriptomes of silencing control (sicon) and PLAUR silenced (PLAURsi) MDA-MB-231 breast cancer cells on treatment with radiation. We isolated RNA from the cells, synthesized cDNA and measured the gene expression changes by microarray. We identified 24 downregulated and 53 upregulated genes, which were significantly (P-value < 0.005) affected by PLAUR silencing. Our analysis revealed 415 canonical pathways and 743 causal disease networks affected on silencing PLAUR. Transcriptomic changes and predicted pathways supported and consolidated some of the earlier understanding in the context of PLAUR signaling; including our recent observations in DNA damage and repair process. In addition, we have identified several novel pathways where PLAUR is implicated.