Metabolomic-Based Approaches for Endometrial Cancer Diagnosis and Prognosis: A Review

Endometrial cancer, the most prevalent gynecological malignancy in developed countries, is experiencing a sustained rise in both its incidence and mortality rates, primarily attributed to extended life expectancy and lifestyle factors. Currently, the absence of precise diagnostic tools hampers the effective management of the expanding population of women at risk of developing this disease. Furthermore, patients diagnosed with endometrial cancer require precise risk stratification to align with optimal treatment planning. Metabolomics technology offers a unique insight into the molecular landscape of endometrial cancer, providing a promising approach to address these unmet needs. This comprehensive literature review initiates with an overview of metabolomic technologies and their intrinsic workflow components, aiming to establish a fundamental understanding for the readers. Subsequently, a detailed exploration of the existing body of research is undertaken with the objective of identifying metabolite biomarkers capable of enhancing current strategies for endometrial cancer diagnosis, prognosis, and recurrence monitoring. Metabolomics holds vast potential to revolutionize the management of endometrial cancer by providing accuracy and valuable insights into crucial aspects.

Biomarkers found in the tumor interstitial fluid may help explain the differential behavior among keratinocyte carcinomas

Basal Cell Carcinomas (BCC) and cutaneous Squamous Cell Carcinomas (SCC) are the most frequent types of cancer, and both originate from the keratinocyte transformation, giving rise to the group of tumors called keratinocyte carcinomas (KC). The invasive behavior is different in each group of KC and may be influenced by their tumor microenvironment. The principal aim of the study is to characterize the protein profile of the Tumor Interstitial Fluid (TIF) of KC to evaluate changes in the microenvironment that could be associated with their different invasive and metastatic capabilities. We obtained TIF from 27 skin biopsies and conducted a label-free quantitative proteomic analysis comparing 7 BCCs, 16 SCCs, and 4 Normal Skins. A total of 2945 proteins were identified, 511 of them quantified in more than half of the samples of each tumoral type. The proteomic analysis revealed differentially expressed TIF-proteins that could explain the different metastatic behavior in both KC. In detail, the SCC samples disclosed an enrichment of proteins related to cytoskeleton, such as Stratafin and Ladinin1. Previous studies found their up-regulation positively correlated with tumor progression. Furthermore, the TIF of SCC samples was enriched with the cytokines S100A8/S100A9. These cytokines influence the metastatic output in other tumors through the activation of NF-kB signaling. According to this, we observed a significant increase in nuclear NF-kB subunit p65 in SCCs but not in BCCs. In addition, the TIF of both tumors was enriched with proteins involved in the immune response, highlighting the relevance of this process in the composition of the tumor environment. Thus, the comparison of the TIF composition of both KC provides the discovery of a new set of differential biomarkers. Among them, secreted cytokines such as S100A9 may help explain the higher aggressiveness of SCCs, while Cornulin is a specific biomarker for BCCs. Finally, the proteomic landscape of TIF provides key information on tumor growth and metastasis, which can contribute to the identification of clinically applicable biomarkers that may be used in the diagnosis of KC, as well as therapeutic targets.

Oxidative stress-induced FAK activation contributes to uterine serous carcinoma aggressiveness

Uterine serous carcinoma (USC) is an aggressive form of endometrial cancer (EC), characterized by its high propensity for metastases. In fact, while endometrioid endometrial carcinoma (EEC), which accounts for 85% of EC, presents a good prognosis, USC is the most frequently fatal. Herein, we used for the first time a peptide-based tyrosine-kinase-activity profiling approach to quantify the changes in tyrosine kinase activation between USC and EEC. Among the tyrosine kinases highly activated in USC, we identified focal adhesion kinase (FAK). We conducted mechanistic studies using cellular models. In a USC cell line, targeting FAK either by inhibitors PF-573228 and defactinib (VS-6063) or by gene silencing limits 3D cell growth and reduces cell migration. Moreover, results from our studies suggest that oxidative stress is increased in USC tumors compared to EEC ones. Reactive oxygen species (ROS) induce tyrosine phosphorylation of FAK and a concomitant tyrosine phosphorylation of paxillin, a mediator of FAK signal transduction. Mechanistically, by tracking hundreds of individual cells per condition, we show that ROS increased cell distance and migration velocity, highlighting the role of ROS-FAK-PAX signaling in cell migration. Both defactinib and ROS scavenger N-acetylcysteine (NAC) revert this effect, pointing toward ROS as potential culprits for the increase in USC cell motility. A proof of concept of the role of FAK in controlling cell growth was obtained in in vivo experiments using cancer-tissue-originated spheroids (CTOS) and a patient-derived orthotopic xenograft model (orthoxenograft/PDOX). Defactinib reduces cell proliferation and protein oxidation, supporting a pro-tumoral antioxidant role of FAK, whereas antioxidant NAC reverts FAK inhibitor effects. Overall, our data points to ROS-mediated FAK activation in USC as being responsible for the poor prognosis of this tumor type and emphasize the potential of FAK inhibition for USC treatment.

Abdominal tumors in patients with neurofibromatosis type I: Genotype-phenotype relationships

BACKGROUND

Gastrointestinal stromal tumors have been detected in 25% of the necropsies performed on NF1 patients, but have been reported only in 7% of NF1 patients in the largest series. Such data imply an important gap between the true presence of tumors and those diagnosed. Few genotype-phenotype relationships have been described but to date none referring to abdominal tumors.

OBJECTIVES

Evaluate retrospectively the efficacy of a regular and proactive follow-up of NF1 patients to early diagnose abdominal tumors and report their mutations.

METHODS

Cohort study performed between 2010 and 2020, with 43 NF1 adult patients followed at our Dermatology department.

RESULTS

Eight abdominal tumors were diagnosed in six patients, meaning that 14% of the followed patients developed an abdominal tumor. Five patients (83%) were asymptomatic. Five (83.3%) had a family history of NF1 with abdominal tumors (patients 1,2 and 3,4,5 were relatives).

CONCLUSIONS

Although currently gastrointestinal routine screening investigations for asymptomatic patients are not recommended in the guidelines, the family aggregation in our series suggests it should be considered a close follow-up of the relatives of a patient with an NF1-related abdominal tumor. Also, for the first time, two mutations [c.2041C > T (p.Arg681Ter) and c.4537C > T (p.Arg1513*)] have been associated with family aggregation of abdominal tumors in NF1 patients.

Metabolomic Analysis Points to Bioactive Lipid Species and Acireductone Dioxygenase 1 (ADI1) as Potential Therapeutic Targets in Poor Prognosis Endometrial Cancer

Simple Summary

Uterine serous carcinoma is considered a rare and aggressive variant of endometrial cancer that accounts for 10% of all endometrial cancers diagnosed but is responsible for 40% of endometrial cancer-related deaths. Unfortunately, current treatments for serous endometrial carcinoma are ineffective. Therefore, there is a need to find new therapeutic targets. The aim of this study was to analyse the metabolic profile of serous cancer in order to identify new molecules and thereby define potential therapeutic targets. We observed that most of the differential metabolites are lipid species (suggesting the important role of the lipid metabolism). In addition, we found an increase in 2-Oxo-4-methylthiobutanoic acid (synthesised by the ADI1 enzyme) in serous carcinomas. Using public database analysis and immunohistochemistry, we established a correlation between elevated ADI1 levels and serous carcinoma. Furthermore, the ectopic modification of ADI1 expression in vitro revealed the ability of ADI1 to induce pathological cell migration and invasion capabilities.

Abstract

Metabolomic profiling analysis has the potential to highlight new molecules and cellular pathways that may serve as potential therapeutic targets for disease treatment. In this study, we used an LC-MS/MS platform to define, for the first time, the specific metabolomic signature of uterine serous carcinoma (SC), a relatively rare and aggressive variant of endometrial cancer (EC) responsible for 40% of all endometrial cancer-related deaths. A metabolomic analysis of 31 ECs (20 endometrial endometrioid carcinomas (EECs) and 11 SCs) was performed. Following multivariate statistical analysis, we identified 232 statistically different metabolites among the SC and EEC patient samples. Notably, most of the metabolites identified (89.2%) were lipid species and showed lower levels in SCs when compared to EECs. In addition to lipids, we also documented metabolites belonging to amino acids and purine nucleotides (such as 2-Oxo-4-methylthiobutanoic acid, synthesised by acireductone dioxygenase 1 (ADI1) enzyme), which showed higher levels in SCs. To further investigate the role of ADI1 in SC, we analysed the expression protein levels of ADI1 in 96 ECs (67 EECs and 29 SCs), proving that the levels of ADI1 were higher in SCs compared to EECs. We also found that ADI1 mRNA levels were higher in p53 abnormal ECs compared to p53 wild type tumours. Furthermore, elevated ADI1 mRNA levels showed a statistically significant negative correlation with overall survival and progression-free survival among EEC patients. Finally, we tested the ability of ADI1 to induce migration and invasion capabilities in EC cell lines. Altogether, these results suggest that ADI1 could be a potential therapeutic target in poor-prognosis SCs and other Ecs with abnormal p53 expression.

ARID1A-deficient cells require HDAC6 for progression of endometrial carcinoma

AT‐rich interactive domain‐containing protein 1A (ARID1A) loss‐of‐function mutation accompanied by a loss of ARID1A protein expression is frequently observed in endometrial carcinomas. However, the molecular mechanisms linking these genetic changes to the altered pathways regulating tumour initiation, maintenance and/or progression remain poorly understood. Thus, the main aim of this study was to analyse the role of ARID1A loss of function in endometrial tumorigenesis. Here, using different endometrial in vitro and in vivo models, such as tumoral cell lines, 3D primary cultures and metastatic or genetically modified mouse models, we show that altered expression of ARID1A is not enough to initiate endometrial tumorigenesis. However, in an established endometrial cancer context, ARID1A loss of function accelerates tumoral progression and metastasis through the disruption of the G2/M cell cycle checkpoint and ATM/ATR‐mediated DNA damage checkpoints, increases epithelial cell proliferation rates and induces epithelial mesenchymal transition through the activation of histone deacetylase 6 (HDAC6). Next, we demonstrated that the inhibition of HDAC6 function, using the HDAC6‐specific inhibitor ACY1215 or by transfection with HDAC6 short hairpin RNA (shRNA), can reverse the migratory and invasive phenotype of ARID1A‐knockdown cells. Further, we also show that inhibition of HDAC6 activity causes an apoptotic vulnerability to etoposide treatments in ARID1A‐deficient cells. In summary, the findings exposed in this work indicate that the inhibition of HDAC6 activity is a potential therapeutic strategy for patients suffering from ARID1A‐mutant endometrial cancer diagnosed in advanced stages.

BRAFV600E Mutant Allele Frequency (MAF) Influences Melanoma Clinicopathologic Characteristics

BACKGROUND

Cutaneous melanoma shows high variability regarding clinicopathological presentation, evolution and prognosis.

METHODS

Next generation sequencing was performed to analyze hotspot mutations in different areas of primary melanomas (MMp) and their paired metastases. Clinicopathological features were evaluated depending on the degree of variation of the BRAFV600E mutant allele frequency (MAF) in MMp.

RESULTS

In our cohort of 14 superficial spreading, 10 nodular melanomas and 52 metastases, 17/24 (71%) melanomas had a BRAFV600E mutation and 5/24 (21%) had a NRASQ61 mutation. We observed a high variation of BRAFV600E MAF (H-BRAFV600E) in 7/17 (41%) MMp. The H-BRAFV600E MMp were all located on the trunk, had lower Breslow and mitotic indexes and predominantly, a first nodal metastasis. Regions with spindled tumor cells (Spin) and high lymphocytic infiltrate (HInf) were more frequent in the H-BRAFV600E patients (4/7; 57%), whereas regions with epithelial tumor cells (Epit) and low lymphocytic infiltrate (LInf) were predominant (6/10; 60%) and exclusive in the low BRAFV600E MAF variation tumors (L-BRAFV600E). The H-BRAFV600E/Spin/HInf MMp patients had better prognostic features and nodal first metastasis.

CONCLUSIONS

The H-BRAFV600E MMp were located on the trunk, had better prognostic characteristics, such as lower Breslow and mitotic indexes as well as high lymphocytic infiltrate.

Detection of somatic mutations in peritoneal lavages and plasma of endometrial cancer patients: A proof-of-concept study

Endometrial cancer (EC) is the most common gynecologic malignancy in developed countries. Although most patients are diagnosed at early stages, 15-20% will relapse despite local treatment. Presently, there are no reliable markers to identify patients with worse outcomes who may benefit from adjuvant treatments, such as chemotherapy, and liquid biopsies may be of use in this setting. Peritoneal lavages are systematically performed during endometrial surgery but little data are available about their potential as liquid biopsies. We analyzed KRAS and PIK3CA mutations in paired surgical biopsies, blood and cytology-negative peritoneal lavages in a cohort of 50 EC patients. Surgical biopsies were submitted to next-generation sequencing (NGS) while circulating-free DNA (cfDNA) purified from plasma and peritoneal lavages was analyzed for KRAS and PIK3CA hotspot mutations using a sensitive quantitative polymerase chain reaction (PCR) assay. NGS of biopsies revealed KRAS, PIK3CA or concomitant KRAS + PIK3CA mutations in 33/50 (66%) EC patients. Of those, 19 cases carried hotspot mutations. Quantitative PCR revealed KRAS and/or PIK3CA mutations in the lavages of 9/19 (47.4%) hotspot EC patients. In contrast, only 2/19 (10.5%) blood samples from hotspot EC patients were positive. Mutations found in cfDNA consistently matched those in paired biopsies. One of the two patients positive in plasma and lavage died in less than 6 months. In conclusion, mutational analysis in peritoneal lavages and blood from early stage EC is feasible. Further studies are warranted to determine if it might help to identify patients with worse prognosis. Human genes discussed: KRAS, KRAS proto-oncogene, GTPase; PIK3CA, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha.

Descriptive study of naevus involution in a series of 74 patients with atypical naevus syndrome under SIAscopy digital follow-up

BACKGROUND

Characterization of nevi involution could help to understand the biological behaviour of melanocytic neoplasms.

OBJECTIVE

To describe the frequency and morphology of naevus involution in a series of patients with atypical naevus syndrome under digital follow-up with a SIAscopy program and, in a small sample of fading nevi, to analyse histopathological features and immunohistochemical biomarkers.

METHODS

Seventy-four patients registered from April 2007 to July 2014 in the SIAscopy system of the Department of Dermatology of Hospital Arnau de Vilanova of Lleida, Spain, were reviewed. Fourteen naevus cases with fading features were prospectively excised during follow-up. Eleven already excised naevus controls were randomly selected from our archive.

RESULTS

We observed that 81% of patients showed, at least, one involutive naevus and 25% of recorded nevi presented this phenomenon; the mean time of involution was 46.7 months. The predominant structural pattern was reticular (>70%), and the most frequently observed regression structures were vascular (33.8%). Histopathological significant higher intensity of inflammatory infiltrate in controls and higher presence of laminar and compact fibrosis and increase of vessels in cases were demonstrated. Regarding immunohistochemical biomarkers, only higher expression of cytoplasmic activated caspase 3 in controls was significant.

CONCLUSIONS

Naevus involution is a common phenomenon in patients with dysplastic naevus syndrome. It is usually a slow process, more frequent in naevus with reticular pattern. SIAscopy regression structures are uncommon, with the exception of vascular ones. Histologically, fading involutive pattern is characterized by scarce inflammatory infiltrate and melanophages, delicate fibrosis and increase of vessels.

EV-associated miRNAs from peritoneal lavage as potential diagnostic biomarkers in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is the third leading cause of cancer-related mortality worldwide. Current systematic methods for diagnosing have inherent limitations so development of a minimally-invasive diagnosis, based on the identification of sensitive biomarkers in liquid biopsies could therefore facilitate screening among population at risk.

METHODS

In this study, we aim to develop a novel approach to identify highly sensitive and specific biomarkers by investigating the use of extracellular vesicles (EVs) isolated from the peritoneal lavage as a source of potential miRNA diagnostic biomarkers. We isolated EVs by ultracentrifugation from 25 ascitic fluids and 25 peritoneal lavages from non-cancer and CRC patients, respectively. Analysis of the expression of EV-associated miRNAs was performed using Taqman OpenArray technology through which we could detect 371 miRNAs.

RESULTS

210 miRNAs were significantly dysregulated (adjusted p value < 0.05 and abs(logFC) ≥ 1). The top-10 miRNAs, which had the AUC value higher than 0.95, were miRNA-199b-5p, miRNA-150-5p, miRNA-29c-5p, miRNA-218-5p, miRNA-99a-3p, miRNA-383-5p, miRNA-199a-3p, miRNA-193a-5p, miRNA-10b-5p and miRNA-181c-5p.

CONCLUSIONS

This finding opens the avenue to the use of EV-associated miRNA of peritoneal lavages as an untapped source of biomarkers for CRC.

EV-Associated miRNAs from Peritoneal Lavage are a Source of Biomarkers in Endometrial Cancer

Endometrial cancer (EC) is the sixth most common cancer in women worldwide and is responsible for more than 89,000 deaths every year. Mortality is associated with presence of poor prognostic factors at diagnosis, i.e., diagnosis at an advanced stage, with a high grade and/or an aggressive histology. Development of novel approaches that would permit us to improve the clinical management of EC patients is an unmet need. In this study, we investigate a novel approach to identify highly sensitive and specific biomarkers of EC using extracellular vesicles (EVs) isolated from the peritoneal lavage of EC patients. EVs of peritoneal lavages of 25 EC patients were isolated and their miRNA content was compared with miRNAs of EVs isolated from the ascitic fluid of 25 control patients. Expression of the EV-associated miRNAs was measured using the Taqman OpenArray technology that allowed us to detect 371 miRNAs. The analysis showed that 114 miRNAs were significantly dysregulated in EC patients, among which eight miRNAs, miRNA-383-5p, miRNA-10b-5p, miRNA-34c-3p, miRNA-449b-5p, miRNA-34c-5p, miRNA-200b-3p, miRNA-2110, and miRNA-34b-3p, demonstrated a classification performance at area under the receiver operating characteristic curve (AUC) values above 0.9. This finding opens an avenue for the use of EV-associated miRNAs of peritoneal lavages as an untapped source of biomarkers for EC.

Cytoplasmic cyclin D1 regulates glioblastoma dissemination

Glioblastoma (GBM) is a highly invasive brain neoplasia with an elevated recurrence rate after surgical resection. The cyclin D1 (Ccnd1)/Cdk4-retinoblastoma 1 (RB1) axis is frequently altered in GBM, leading to overproliferation by RB1 deletion or by Ccnd1-Cdk4 overactivation. High levels of Ccnd1-Cdk4 also promote GBM cell invasion by mechanisms that are not so well understood. The purpose of this work is to elucidate the in vivo role of cytoplasmic Ccnd1-Cdk4 activity in the dissemination of GBM. We show that Ccnd1 activates the invasion of primary human GBM cells through cytoplasmic RB1-independent mechanisms. By using GBM mouse models, we observed that evaded GBM cells showed cytoplasmic Ccnd1 colocalizing with regulators of cell invasion such as RalA and paxillin. Our genetic data strongly suggest that, in GBM cells, the Ccnd1-Cdk4 complex is acting upstream of those regulators. Accordingly, expression of Ccnd1 induces focal adhesion kinase, RalA and Rac1 activities. Finally, in vivo experiments demonstrated increased GBM dissemination after expression of membrane-targeted Ccnd1. We conclude that Ccnd1-Cdk4 activity promotes GBM dissemination through cytoplasmic and RB1-independent mechanisms. Therefore, inhibition of Ccnd1-Cdk4 activity may be useful to hinder the dissemination of recurrent GBM. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Metabotyping human endometrioid endometrial adenocarcinoma reveals an implication of endocannabinoid metabolism

Metabolomics, an essential technique in precision medicine, contributes to the molecular fingerprinting of tumours, further helping to understand their pathogenesis. In this work, using a LC-ESI-QTOF-MS/MS platform, we demonstrated the existence of a specific metabolomic signature which could define endometrioid endometrial carcinoma (EEC), arising the endocannabinoid system as a potential pathway involved in EC pathogenesis. Metabolomics could also shed light in the processes involved in myometrial invasion, proposing new targets for possible therapeutic intervention. Consequently, we also described a different metabolomic profile in surface endometrioid carcinoma and myometrial invasive front. We validated pathways disclosed by metabolomics by immunohistochemistry. Specifically, endocannabinoid and purine metabolism could be involved in tumor myometrial invasion.

Tumour-microenvironmental blood flow determines a metabolomic signature identifying lysophospholipids and resolvin D as biomarkers in endometrial cancer patients

PURPOSE

We aimed to study the potential influence of tumour blood flow -obtained from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI)- in the metabolomic profiles of endometrial tumours.

METHODS

Liquid chromatography coupled to mass spectrometry established the metabolomic profile of endometrial cancer lesions exhibiting high (n=12) or low (n=14) tumour blood flow at DCE-MRI. Univariate and multivariate statistics (ortho-PLS-DA, a random forest (RF) classifier and hierarchical clustering) and receiver operating characteristic (ROC) curves were used to establish a panel for potentially discriminating tumours with high versus low blood flow.

RESULTS

Tumour blood flow is associated with specific metabolomic signatures. Ortho-PLS-DA and RF classifier resulted in well-defined clusters with an out-of-bag error lower than 8%. We found 28 statistically significant molecules (False Discovery Rate corrected p<0.05). Based on exact mass, retention time and isotopic distribution we identified 9 molecules including resolvin D and specific lysophospholipids associated with blood flow, and hence with a potentially regulatory role relevant in endometrial cancer.

CONCLUSIONS

Tumour flow parameters at DCE-MRI quantifying vascular tumour characteristics are reflected in corresponding metabolomics signatures and highlight disease mechanisms that may be targetable by novel therapies.

Characterization of cytoplasmic cyclin D1 as a marker of invasiveness in cancer

Cyclin D1 (Ccnd1) is a proto-oncogen amplified in many different cancers and nuclear accumulation of Ccnd1 is a characteristic of tumor cells. Ccnd1 activates the transcription of a large set of genes involved in cell cycle progress and proliferation. However, Ccnd1 also targets cytoplasmic proteins involved in the regulation of cell migration and invasion. In this work, we have analyzed by immunohistochemistry the localization of Ccnd1 in endometrial, breast, prostate and colon carcinomas with different types of invasion. The number of cells displaying membranous or cytoplasmic Ccnd1 was significantly higher in peripheral cells than in inner cells in both collective and pushing invasion patterns of endometrial carcinoma, and in collective invasion pattern of colon carcinoma. Also, the cytoplasmic localization of Ccnd1 was higher when tumors infiltrated as single cells, budding or small clusters of cells. To evaluate cytoplasmic function of cyclin D1, we have built a variant (Ccnd1-CAAX) that remains attached to the cell membrane therefore sequestering this cyclin in the cytoplasm. Tumor cells harboring Ccnd1-CAAX showed high levels of invasiveness and metastatic potential compared to those containing the wild type allele of Ccnd1. However, Ccnd1-CAAX expression did not alter proliferative rates of tumor cells. We hypothesize that the role of Ccnd1 in the cytoplasm is mainly associated with the invasive capability of tumor cells. Moreover, we propose that subcellular localization of Ccnd1 is an interesting guideline to measure cancer outcome.

Tumor Heterogeneity in Endometrial Carcinoma: Practical Consequences

Endometrial carcinoma (EC) shows intertumor heterogeneity, with several different histologic types differing in their morphologic and molecular features. There is also intratumoral morphologic heterogeneity, with different neoplastic cell components within the same tumor, with different morphologic and molecular features. In this article, we discuss the consequences of tumor heterogeneity in EC at the morphologic and molecular levels, by describing some illustrative examples produced by the research team. They are (1) morphologic heterogeneity in conventional EC and mixed tumors, (2) EC with microsatellite instability, (3) branched evolution as shown by exome sequencing analysis, (4) morphologic, molecular, and metabolomic differences between the tumor surface and myometrial invasion front, (5) tumor heterogeneity at the microenviromental level, (6) the sensitivity of endometrial aspirates to detect tumor heterogeneity in EC, and (7) sampling strategies to detect tumor heterogeneity in hysterectomy specimens. Tumor heterogeneity may have an important clinical impact, since it can be challenging to identify minor tumor cell populations that may have an impact on diagnosis, prognosis, and therapeutic decisions for patients with EC.

Immunohistochemical analysis of T-type calcium channels in acquired melanocytic naevi and melanoma

BACKGROUND

Cutaneous malignant melanoma arises from transformed melanocytes de novo or from congenital or acquired melanocytic naevi. We have recently reported that T-type Ca²⁺ channels (TT-Cs) are upregulated in human melanoma and play an important role in cell proliferation.

OBJECTIVES

To describe for the first time in formalin-fixed paraffin-embedded tissue the immunoexpression of TT-Cs in biopsies of normal skin, acquired melanocytic naevi and melanoma, in order to evaluate their role in melanomagenesis and/or tumour progression, their utility as prognostic markers and their possible use in targeted therapies.

METHODS

Tissue samples from normal skin, melanocytic naevi and melanoma were subjected to immunohistochemistry for two TT-Cs (Cav3.1, Cav3.2); markers of proliferation (Ki67), the cell cycle (cyclin D1), hypoxia (Glut1), vascularization (CD31) and autophagy (LC3); BRAF V600E mutation (VE1) and phosphatase and tensin homologue (PTEN). Immunostaining was evaluated by histoscore. In silico analysis was used to assess the prognostic value of TT-C overexpression.

RESULTS

TT-C immunoexpression increased gradually from normal skin to common naevi, dysplastic naevi and melanoma samples, but with differences in the distribution of both isoforms. Particularly, Cav3.2 expression was significantly higher in metastatic melanoma than in primary melanoma. Statistical correlation showed a linear interaction between PTEN loss/BRAF V600E/Cav3.1/LC3/ Ki67/cyclin D1/Cav3.2/Glut1. Disease-free survival (DFS) and overall survival correlated inversely with overexpression of Cav3.2. DFS also correlated inversely with overexpression of Cav3.1.

CONCLUSIONS

TT-C immunoexpression on melanocytic neoplasms is consistent with our previous in vitro studies and appears to be related to tumour progression. TT-C upregulation can be considered as a prognostic marker using The Cancer Genome Atlas database. The high expression of Cav3.2 in metastatic melanoma encourages the investigation of the use of TT-C blockers in targeted therapies.

Autophagy orchestrates adaptive responses to targeted therapy in endometrial cancer

Targeted therapies in endometrial cancer (EC) using kinase inhibitors rarely result in complete tumor remission and are frequently challenged by the appearance of refractory cell clones, eventually resulting in disease relapse. Dissecting adaptive mechanisms is of vital importance to circumvent clinical drug resistance and improve the efficacy of targeted agents in EC. Sorafenib is an FDA-approved multitarget tyrosine and serine/threonine kinase inhibitor currently used to treat hepatocellular carcinoma, advanced renal carcinoma and radioactive iodine-resistant thyroid carcinoma. Unfortunately, sorafenib showed very modest effects in a multi-institutional phase II trial in advanced uterine carcinoma patients. Here, by leveraging RNA-sequencing data from the Cancer Cell Line Encyclopedia and cell survival studies from compound-based high-throughput screenings we have identified the lysosomal pathway as a potential compartment involved in the resistance to sorafenib. By performing additional functional biology studies we have demonstrated that this resistance could be related to macroautophagy/autophagy. Specifically, our results indicate that sorafenib triggers a mechanistic MAPK/JNK-dependent early protective autophagic response in EC cells, providing an adaptive response to therapeutic stress. By generating in vivo subcutaneous EC cell line tumors, lung metastatic assays and primary EC orthoxenografts experiments, we demonstrate that targeting autophagy enhances sorafenib cytotoxicity and suppresses tumor growth and pulmonary metastasis progression. In conclusion, sorafenib induces the activation of a protective autophagic response in EC cells. These results provide insights into the unopposed resistance of advanced EC to sorafenib and highlight a new strategy for therapeutic intervention in recurrent EC.

Oral intake of genetically engineered high-carotenoid corn ameliorates hepatomegaly and hepatic steatosis in PTEN haploinsufficient mice

Non-alcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease. Here we show that a mouse model of haploinsufficiency in the lipid and protein phosphatase and tensin homolog protein (PTEN(+/-)) exhibits hepatomegaly, increased liver lipogenic gene expression (SREBP-1C and PPARγ) and hepatic lesions analogous to human NAFLD. The livers of PTEN(+/-) mice also contained lower levels of retinoic acid (RA) than normal, similarly to human NAFLD patients. The RA signaling pathway thus offers a novel therapeutic target for the treatment of NAFLD although the impact of nutrition in this context is unclear. We therefore fed PTEN(+/-) mice for 36weeks a diet containing genetically engineered high-carotenoid corn (HCAR) to investigate its potential beneficial effects on the hepatic symptoms of NAFLD. The HCAR diet reduced hepatomegaly and promoted the repartitioning of fatty acids in the liver, away from triacylglycerol storage. At the molecular level, the HCAR diet clearly reduced lipogenic gene expression, boosted catabolism, and increased hepatic RA levels. These results set the stage for human trials to evaluate the use of high-carotenoid foods for the reduction or prevention of steatosis in NAFLD.