Reversible and bidirectional signaling of notch ligands.

The Notch signaling pathway is a direct cell-cell communication system involved in a wide variety of biological processes, and its disruption is observed in several pathologies. The pathway is comprised of a ligand-expressing (sender) cell and a receptor-expressing (receiver) cell. The canonical ligands are members of the Delta/Serrate/Lag-1 (DSL) family of proteins. Their binding to a Notch receptor in a neighboring cell induces a conformational change in the receptor, which will undergo regulated intramembrane proteolysis (RIP), liberating the Notch intracellular domain (NICD). The NICD is translocated to the nucleus and promotes gene transcription. It has been demonstrated that the ligands can also undergo RIP and nuclear translocation, suggesting a function for the ligands in the sender cell and possible bidirectionality of the Notch pathway. Although the complete mechanism of ligand processing is not entirely understood, and its dependence on Notch receptors has not been ruled out. Also, ligands have autonomous functions beyond Notch activation. Here we review the concepts of reverse and bidirectional signalization of DSL proteins and discuss the characteristics that make them more than just ligands of the Notch pathway.

Oral lichen planus clinician reported outcome measure: Development, content validity, and further development.

OBJECTIVE: To establish and test a clinician-reported outcome measure of oral lichen planus (OLP): OLP Investigator global assessment (IGA). METHODS: OLP IGA scale was tested with retrospective data from clinical practice and a phase II clinical trial. A comparison of the OLP IGA score with patient-reported outcomes was completed. RESULTS: Clinical Practice: The mean (SD) OLP IGA score (0-4) in 107 OLP patients was 1.8 (1.0) with correlation of 0.25-0.48 (p value 0.01 - <0.0001) with symptom scores. There was a significant increase in OLP symptoms based on OLP IGA score. CLINICAL TRIAL: The mean (SD) OLP IGA score in 137 research participants was 2.5 (1.2) with correlation of 0.43-0.52 (all p values <0.0001) with symptoms scores. There was a significant increase in OLP symptoms based on OLP IGA score. Forty-seven (35%) participants in the phase 2 study had an improvement in the OLP IGA score of ≥2. There were significant improvements in all symptoms scores in relation to the change in IGA score. CONCLUSIONS: The OLP IGA is designed to assess changes in symptomatic OLP lesions and is appropriate for use across the full range of symptomatic OLP severity and represents a scale with utility in clinical practice and clinical trials.

Lysophosphatidylinositol Promotes Chemotaxis and Cytokine Synthesis in Mast Cells with Differential Participation of GPR55 and CB2 Receptors.

Mast cells (MCs) are the main participants in the control of immune reactions associated with inflammation, allergies, defense against pathogens, and tumor growth. Bioactive lipids are lipophilic compounds able to modulate MC activation. Here, we explored some of the effects of the bioactive lipid lysophosphatidylinositol (LPI) on MCs. Utilizing murine bone marrow-derived mast cells (BMMCs), we found that LPI did not cause degranulation, but slightly increased FcεRI-dependent ß-hexosaminidase release. However, LPI induced strong chemotaxis together with changes in LIM kinase (LIMK) and cofilin phosphorylation. LPI also promoted modifications to actin cytoskeleton dynamics that were detected by an increase in cell size and interruptions in the continuity of the cortical actin ring. The chemotaxis and cortical actin ring changes were dependent on GPR55 receptor activation, since the specific agonist O1602 mimicked the effects of LPI and the selective antagonist ML193 prevented them. The LPI and O1602-dependent stimulation of BMMC also led to VEGF, TNF, IL-1α, and IL-1ß mRNA accumulation, but, in contrast with chemotaxis-related processes, the effects on cytokine transcription were dependent on GPR55 and cannabinoid (CB) 2 receptors, since they were sensitive to ML193 and to the specific CB2 receptor antagonist AM630. Remarkably, GPR55-dependent BMMC chemotaxis was observed towards conditioned media from distinct mouse and human cancer cells. Our data suggest that LPI induces the chemotaxis of MCs and leads to cytokine production in MC in vitro with the differential participation of GPR55 and CB2 receptors. These effects could play a significant role in the recruitment of MCs to tumors and the production of MC-derived pro-angiogenic factors in the tumor microenvironment.

Epidemiology and Molecular Biology of HPV Variants in Cervical Cancer: The State of the Art in Mexico.

Cervical cancer (CC) continues to be a major public health problem in Mexico, ranking second among cancers in women. A persistent infection with human papillomaviruses (HPV) is the main risk factor for CC development. In addition, a significant fraction of other cancers including those of the anus, oropharynx, and penis are also related to HPV infection. In CC, HPV-16 is the most prevalent high-risk HPV type, followed by HPV-18, both being responsible for 70% of cases. HPV intratype variant lineages differ in nucleotide sequences by 1-10%, while sublineages differ by 0.5-1%. Several studies have postulated that the nucleotide changes that occur between HPV intratype variants are reflected in functional differences and in pathogenicity. Moreover, it has been demonstrated that HPV-16 and -18 intratype variants differentially affect molecular processes in infected cells, changing their biological behavior that finally impacts in the clinical outcome of patients. Mexico has participated in providing knowledge on the geographical distribution of intratype variants of the most prevalent HPVs in premalignant lesions of the cervix and cervical cancer, as well as in other HPV-related tumors. In addition, functional studies have been carried out to assess the cellular effects of intratype variations in HPV proteins. This review addresses the state of the art on the epidemiology of HPV-16 and HPV-18 intratype variants in the Mexican population, as well as their association with persistence, precancer and cervical cancer, and functional aspects related to their biological behavior.

The Polyphenols α-Mangostin and Nordihydroguaiaretic Acid Induce Oxidative Stress, Cell Cycle Arrest, and Apoptosis in a Cellular Model of Medulloblastoma.

Medulloblastoma is a common malignant brain tumor in the pediatric age. The current therapeutics present serious collateral effects. Polyphenols α-mangostin and nordihydroguaiaretic acid (NDGA) exert potent antitumoral activity in different cancer models, although their antitumoral effects have not been described in medulloblastoma cells yet. This study aimed to examine the proapoptotic effects of these polyphenols on human medulloblastoma cells. Medulloblastoma cell line Daoy was incubated with increasing concentrations of α-mangostin or NDGA for 24 h. The cell viability was analyzed using crystal violet and trypan blue dyes. Determination of the glutathione (GSH)/glutathione disulfide (GSSG) ratio and levels of carbonylated proteins was performed to evaluate the oxidative stress. Cell cycle progression and induction of cell death by fluorochrome-couple and TUNEL assays were evaluated using flow cytometry assays. Individual treatments with α-mangostin or NDGA decreased the viability of Daoy cells in a dose-dependent manner, inducing G2/M and S-G2/M cell cycle arrest, respectively. Both polyphenols induced cell death and increased oxidative stress. Very interestingly, α-mangostin showed more potent effects than NDGA. Our results indicate that α-mangostin and NDGA exert important cytostatic and cytotoxic effects in the Daoy cell line. These data highlight the potential usefulness of these compounds as an alternative strategy in medulloblastoma treatment.

Non-Coding RNAs as Key Regulators of Glutaminolysis in Cancer.

Cancer cells exhibit exacerbated metabolic activity to maintain their accelerated proliferation and microenvironmental adaptation in order to survive under nutrient-deficient conditions. Tumors display an increase in glycolysis, glutaminolysis and fatty acid biosynthesis, which provide their energy source. Glutamine is critical for fundamental cellular processes, where intermediate metabolites produced through glutaminolysis are necessary for the maintenance of mitochondrial metabolism. These include antioxidants to remove reactive oxygen species, and the generation of the nonessential amino acids, purines, pyrimidines and fatty acids required for cellular replication and the activation of cell signaling. Some cancer cells are highly dependent on glutamine consumption since its catabolism provides an anaplerotic pathway to feed the Krebs cycle. Intermediate members of the glutaminolysis pathway have been found to be deregulated in several types of cancers and have been proposed as therapeutic targets and prognostic biomarkers. This review summarizes the main players in the glutaminolysis pathway, how they have been found to be deregulated in cancer and their implications for cancer maintenance. Furthermore, non-coding RNAs are now recognized as new participants in the regulation of glutaminolysis; therefore, their involvement in glutamine metabolism in cancer is discussed in detail.

MOLECULAR MARKERS FOR THE DIAGNOSIS OF HIGH-RISK HUMAN PAPILLOMAVIRUS INFECTION AND TRIAGE OF HUMAN PAPILLOMAVIRUS-POSITIVE WOMEN.

Infection with high-risk human papillomavirus (HPV) increases the likelihood of developing cervical cancer (CC). A plethora of cellular processes is required to produce pre-malignant lesions, which in turn may become malignant if left untreated. Those changes are induced by viral oncoproteins, which represent an ideal target to identify the viral presence, or by some particularities of the host that ultimately promote the establishment of CC. This article describes the different methods used for HPV detection and quantification, as well as the current trend of secondary screening approaches to detect premalignant lesions and CC. In addition, we analyzed validated biomarkers and those under clinical investigation for the classification (triage) of women at risk of developing CC after an initial positive HPV test and that could be used as prognostic biomarkers for CC. The use of molecular biomarkers, together with the detection of HPV DNA sequences, provides a high impact diagnostic and prognostic tool in the detection of patients at increased risk of developing CC and also may guide their clinical management. In addition, some of those biomarkers could represent pharmacological targets for the future design of therapeutic approaches to CC treatment.

Correction to: Intratype variants of the E2 protein from human papillomavirus type 18 induce different gene expression profiles associated with apoptosis and cell proliferation.

The Given names of the author Alma Mariana Fuentes-González was incorrectly tagged in original publication and corrected here. The original article has been corrected.

Intratype variants of the E2 protein from human papillomavirus type 18 induce different gene expression profiles associated with apoptosis and cell proliferation.

Persistent infections with high-risk human papillomaviruses (HR-HPVs) are linked to the development of cervical cancer due to a deregulation of the productive viral cycle in the host cell, leading to cell transformation. The E2 viral protein is expressed early during an HPV infection and regulates viral replication and transcription. Other functions have been attributed to E2, such as the promotion of apoptosis that are independent of its role in the regulation of the expression of E6 and E7 viral oncogenes. Moreover, it has been shown that the HPV16 E2 protein has regulatory effects on cellular gene expression, suggesting that it participates in the modulation of different cellular processes. Intratype genomic variations within high-risk HPV types have an impact on the prognosis of HPV-related lesions. Nevertheless, the biological significance of HPV18 E2 intratype variations has not been analysed previously. The aim of this study was to determine whether HPV18 E2 intratype variations differentially modulate gene expression and whether cell-death-related genes are affected by variations in E2. We demonstrate that HPV18 E2 intratype Asian Amerindian (AsAi) and African (Af) variants differentially affect gene expression profiles. Although the E2-AsAi variant was found to modulate a larger number of cellular genes, both E2 variants affected similar cellular processes. Nevertheless, E2-AsAi and E2-Af variants showed differences in their ability to induce apoptosis, where E2-Af had a stronger effect. The differences in gene expression profiles in cells harbouring E2 intratype variants suggest a possible effect on diverse cellular signalling pathways, and this might suggest an approach for identifying biological processes regulated by HPV18 E2 intratype variants.

Deregulation of the Notch pathway as a common road in viral carcinogenesis.

The Notch pathway is a conserved signaling pathway and a form of direct cell-cell communication related to many biological processes during development and adulthood. Deregulation of the Notch pathway is involved in many diseases, including cancer. Almost 20% of all cancer cases have an infectious etiology, with viruses responsible for at least 1.5 million new cancer cases per year. Seven groups of viruses have been classified as oncogenic: hepatitis B and C viruses (HBV and HCV respectively), Epstein-Barr virus (EBV), Kaposi sarcoma-associated herpesvirus (KSHV), human T lymphotropic virus (HTLV-1), human papillomavirus (HPV), and Merkel cell polyomavirus (MCPyV). These viruses share the ability to manipulate a variety of cell pathways that are critical in proliferation and differentiation, leading to malignant transformation. Viral proteins interact directly or indirectly with different members of the Notch pathway, altering their normal function. This review focuses exclusively on the direct interactions of viral oncoproteins with Notch elements, providing a deeper understanding of the dual behavior of the Notch pathway as activator or suppressor of neoplasia in virus-related cancers.

Interaction of the Human Papillomavirus E6 Oncoprotein with Sorting Nexin 27 Modulates Endocytic Cargo Transport Pathways.

A subset of high-risk Human Papillomaviruses (HPVs) are the causative agents of a large number of human cancers, of which cervical is the most common. Two viral oncoproteins, E6 and E7, contribute directly towards the development and maintenance of malignancy. A characteristic feature of the E6 oncoproteins from cancer-causing HPV types is the presence of a PDZ binding motif (PBM) at its C-terminus, which confers interaction with cellular proteins harbouring PDZ domains. Here we show that this motif allows E6 interaction with Sorting Nexin 27 (SNX27), an essential component of endosomal recycling pathways. This interaction is highly conserved across E6 proteins from multiple high-risk HPV types and is mediated by a classical PBM-PDZ interaction but unlike many E6 targets, SNX27 is not targeted for degradation by E6. Rather, in HPV-18 positive cell lines the association of SNX27 with components of the retromer complex and the endocytic transport machinery is altered in an E6 PBM-dependent manner. Analysis of a SNX27 cargo, the glucose transporter GLUT1, reveals an E6-dependent maintenance of GLUT1 expression and alteration in its association with components of the endocytic transport machinery. Furthermore, knockdown of E6 in HPV-18 positive cervical cancer cells phenocopies the loss of SNX27, both in terms of GLUT1 expression levels and its vesicular localization, with a concomitant marked reduction in glucose uptake, whilst loss of SNX27 results in slower cell proliferation in low nutrient conditions. These results demonstrate that E6 interaction with SNX27 can alter the recycling of cargo molecules, one consequence of which is modulation of nutrient availability in HPV transformed tumour cells.

Type-specific persistence and clearance rates of HPV genotypes in the oral and oropharyngeal mucosa in an HIV/AIDS cohort.

BACKGROUND: Oral high-risk human papillomavirus (HR-HPV) infections are frequent and persistent among the HIV-positive population and are associated with an increased risk for head and neck cancer (HNC). In this study, we sought to determine the incidence, persistence and clearance of HPV infections in oral and oropharyngeal samples from HIV/AIDS subjects. METHODS: A longitudinal, observational and analytical study was performed with an ongoing cohort of HIV/AIDS subjects in Mexico City (September 2013-February 2015). The study was approved by institutional committees, and demographic and clinical data were registered. At the baseline and three-month visits, oral examinations and cytobrush samples were obtained. DNA was purified, quantified and used to detect an HPV-L1 gene fragment by nested PCR, using MY09/MY11 and GP5 + /GP6 + primers. HPV DNA products were purified, sequenced and typed according to HPV databases. Risk factors were assessed, and a multivariate modelling approach was used to determine independent effects. RESULTS: This study included 97 HIV/AIDS individuals (91% men [86.4% of which are men who have sex with men], median age: 36 years, 72.2% under HAART). From the baseline visit, HPV was observed in 55.7% (HR-HPV: 26.8%; HPV-18: 24.1%), with a higher HPV-positive samples for smokers (61.1 vs 32.6%, P = .005). The three-month overall HPV incidence was 33.9%; type-specific HPV persistence was 33.3% (HR-HPV: 13.3%); and 13 of the 33 (39.4%) baseline HPV-positive individuals cleared the infection (HR-HPV: 53.8%). CONCLUSIONS: Although HR-HPV persistence was low, and clearance of the infection was observed in most cases, a close follow-up is necessary, given the increase in HNC among HIV-subjects, particularly HPV-related cancer.

Regulation of Cellular Metabolism by High-Risk Human Papillomaviruses.

The alteration of glucose metabolism is one of the first biochemical characteristics associated with cancer cells since most of these cells increase glucose consumption and glycolytic rates even in the presence of oxygen, which has been called “aerobic glycolysis" or the Warburg effect. Human papillomavirus (HPV) is associated with approximately 5% of all human cancers worldwide, principally to cervical cancer. E6 and E7 are the main viral oncoproteins which are required to preserve the malignant phenotype. These viral proteins regulate the cell cycle through their interaction with tumor suppressor proteins p53 and pRB, respectively. Together with the viral proteins E5 and E2, E6 and E7 can favor the Warburg effect and contribute to radio- and chemoresistance through the increase in the activity of glycolytic enzymes, as well as the inhibition of the Krebs cycle and the respiratory chain. These processes lead to a fast production of ATP obtained by Warburg, which could help satisfy the high energy demands of cancer cells during proliferation. In this way HPV proteins could promote cancer hallmarks. However, it is also possible that during an early HPV infection, the Warburg effect could help in the achievement of an efficient viral replication.

HPV-18 E6 Oncoprotein and Its Spliced Isoform E6*I Regulate the Wnt/ß-Catenin Cell Signaling Pathway through the TCF-4 Transcriptional Factor.

The Wnt/ß-catenin signaling pathway regulates cell proliferation and differentiation and its aberrant activation in cervical cancer has been described. Persistent infection with high risk human papillomavirus (HR-HPV) is the most important factor for the development of this neoplasia, since E6 and E7 viral oncoproteins alter cellular processes, promoting cervical cancer development. A role of HPV-16 E6 in Wnt/ß-catenin signaling has been proposed, although the participation of HPV-18 E6 has not been previously studied. The aim of this work was to investigate the participation of HPV-18 E6 and E6*I, in the regulation of the Wnt/ß-catenin signaling pathway. Here, we show that E6 proteins up-regulate TCF-4 transcriptional activity and promote overexpression of Wnt target genes. In addition, it was demonstrated that E6 and E6*I bind to the TCF-4 (T cell factor 4) and ß-catenin, impacting TCF-4 stabilization. We found that both E6 and E6*I proteins interact with the promoter of Sp5, in vitro and in vivo. Moreover, although differences in TCF-4 transcriptional activation were found among E6 intratype variants, no changes were observed in the levels of regulated genes. Furthermore, our data support that E6 proteins cooperate with ß-catenin to promote cell proliferation.

Prevalence of sexually transmitted pathogens associated with HPV infection in cervical samples in a Mexican population.

Cervical cancer development has been mainly associated with persistent human papillomavirus (HPV) infections. However, HPV infection is unlikely to be sufficient to cause cervical cancer, and the contribution of other sexually transmitted infections (STIs) could be the determining factor for cervical lesion-progression. The aim of this study was to estimate the prevalence of STIs associated with HPV-positivity in 201 cervical samples from patients who underwent annual routine gynecological exams. The overall prevalence of STIs was 57.7%, and the most frequent infection was Ureaplasma spp (UP) (39.8%), followed by Gardnerella vaginalis (GV) (25.9%), α-HPV (18.4%), Chlamydia trachomatis (CT) (1.5%), and Mycoplasma genitalium (MG) (0.5%). The highest prevalence rate of multiple non-HPV infections was observed for the age-range 31-40; for papillomavirus infection, the age-range was 21-30. In normal cervical samples, HPV16 was the most prevalent genotype (24.3%), followed by genotypes 58 (13.5%) and 52 (10.8%). Intriguingly, HPV18 was not detected in the study population, and genotypes 52 and 58 were found exclusively in samples with abnormal cytology. Papillomavirus infection with oncogenic types was significantly associated with GV (P = 0.025) and strongly associated with multiple non-HPV pathogens (P = 0.002). The following variables correlated significantly with cytological diagnosis of low-grade squamous intraepithelial lesion (LSIL): GV (P = 0.028), multiple non-HPV infections (P = 0.001), and high-risk HPV positivity (P = 0.001). Epidemiological data from this study will contribute to the molecular detection of sexually transmitted pathogens from screening programs to identify those women who are at risk for developing cervical lesions.

Impact of human papillomavirus coinfections on the risk of high-grade squamous intraepithelial lesion and cervical cancer.

OBJECTIVE: The molecular and epidemiologic effect of human papillomavirus (HPV) coinfections in the risk of developing cervical cancer is yet unclear. The aim of this study was to determine the frequency HPV coinfections at different stages of cervical lesions in the development of cervical cancer and the impact of HPV specific type interactions on high-grade squamous intraepithelial lesions (HSIL) and invasive cervical cancer (ICC) risk. METHODS: HPV testing was performed in 931 cervical samples diagnosed as: negative for intraepithelial lesion or malignancy (NILM); low-grade squamous intraepithelial lesion (LSIL); HSIL; and ICC. For HPV detection and typing two sets of primers from the L1 region were used in the polymerase chain reaction method (PCR) (MY09/MY11/HMB01 and L1C1/L1C2.1/L1C2.2) and HPV type was determined by PCR product sequence. To look for multiple HPV infections, the E6 nested multiplex PCR method was performed in all DNA samples. Odds ratios were calculated as indexes of the strength of the association between the sample category (LSIL/NILM or ICC/HSIL) and the presence of a given viral combination. RESULTS: In HPV positive samples, coinfections are as common in ICC/HSIL as in LSIL/NILM (47.12% and 40.17%, respectively). There is an increased risk to ICC/HSIL when multiple high-risk HPV types are present. The coinfection of HPV68 with HPV16 increases the risk of ICC/HSIL (OR=14.54, P=0.012, after multivariate adjustment), related to the presence of HPV16 or HPV68 alone. CONCLUSIONS: These results sustain that specific HPV coinfections confer an increased risk to develop ICC/HSIL.

Molecular aspects of cervical cancer: a pathogenesis update.

Cervical cancer (CC) is a significant health problem, especially in low-income countries. Functional studies on the human papillomavirus have generated essential advances in the knowledge of CC. However, many unanswered questions remain. This mini-review discusses the latest results on CC pathogenesis, HPV oncogenesis, and molecular changes identified through next-generation technologies. Interestingly, the percentage of samples with HPV genome integrations correlates with the degree of the cervical lesions, suggesting a role in the development of CC. Also, new functions have been described for the viral oncoproteins E5, E6, and E7, resulting in the acquisition and maintenance of cancer hallmarks, including proliferation, immune response evasion, apoptosis, and genomic instability. Remarkably, E5 oncoprotein affects signaling pathways involved in the expression of interferon-induced genes and EGFR-induced proliferation, while E6 and E7 oncoproteins regulate the DNA damage repair and cell cycle continuity pathways. Furthermore, next-generation technologies provide vast amounts of information, increasing our knowledge of changes in the genome, transcriptome, proteome, metabolome, and epigenome in CC. These studies have identified novel molecular traits associated with disease susceptibility, degree of progression, treatment response, and survival as potential biomarkers and therapeutic targets.

Promising predictive molecular biomarkers for cervical cancer (Review).

Cervical cancer (CC) constitutes a serious public health problem. Vaccination and screening programs have notably reduced the incidence of CC worldwide by >80%; however, the mortality rate in low­income countries remains high. The staging of CC is a determining factor in therapeutic strategies: The clinical management of early stages of CC includes surgery and/or radiotherapy, whereas radiotherapy and/or concurrent chemotherapy are the recommended therapeutic strategies for locally advanced CC. The histopathological characteristics of tumors can effectively serve as prognostic markers of radiotherapy response; however, the efficacy rate of radiotherapy may significantly differ among cancer patients. Failure of radiotherapy is commonly associated with a higher risk of recurrence, persistence and metastasis; therefore, radioresistance remains the most important and unresolved clinical problem. This condition highlights the importance of precision medicine in searching for possible predictive biomarkers to timely identify patients at risk of treatment response failure and provide tailored therapeutic strategies according to genetic and epigenetic characteristics. The present review aimed to summarize the evidence that supports the role of several proteins, methylation markers and non­coding RNAs as potential predictive biomarkers for CC.

Potential Transcript-Based Biomarkers Predicting Clinical Outcomes of HPV-Positive Head and Neck Squamous Cell Carcinoma Patients.

Human papillomavirus (HPV)-positive Head and Neck Squamous Cell Carcinomas (HNSCC) comprise a particular cancer entity traditionally associated with better clinical outcomes. Around 25% of HNSCC are HPV positive, HPV16 being the most prevalent type. Nevertheless, close to 30% of the HPV-positive patients have an unfavorable prognosis, revealing that this type of tumor exhibits great heterogeneity leading to different clinical behaviors. Efforts have been made to identify RNA molecules with prognostic value associated with the clinical outcome of patients with HPV-positive HNSCC, with the aim of identifying patients at high risk of metastasis, disease recurrence, and poor survival, who would require closer clinical follow-up and timely intervention. Moreover, the molecular identification of those HPV-positive HNSCC patients with good prognosis will allow the implementation of de-escalating therapeutic strategies, aiming to reduce side effects, resulting in a better quality of life. This review compiles a series of recent studies addressing different methodological and conceptual approaches aimed at searching for potential gene expression-based biomarkers associated with the prognosis of patients with HPV-positive HNSCC.