Semaphorin signaling in cancer cells and in cells of the tumor microenvironment – two sides of a coin

Semaphorins are a large family of secreted and membrane-bound molecules that were initially implicated in the development of the nervous system and in axon guidance. More recently, they have been found to regulate cell adhesion and motility, angiogenesis, immune responses, and tumor progression. Semaphorin receptors, the neuropilins and the plexins, are expressed by a wide variety of cell types, including endothelial cells, bone-marrow-derived cells and cancer cells. Interestingly, a growing body of evidence indicates that semaphorins also have an important role in cancer. It is now known that cancer progression, invasion and metastasis involve not only genetic changes in the tumor cells but also crosstalk between tumor cells and their surrounding non-tumor cells. Through the recruitment of endothelial cells, leukocytes, pericytes and fibroblasts, and the local release of growth factors and cytokines, the tumor microenvironment can mediate tumor-cell survival, tumor proliferation and regulation of the immune response. Moreover, by conferring cancer cells with an enhanced ability to migrate and invade adjacent tissues, extracellular regulatory signals can play a major role in the metastatic process. In this Commentary, we focus on the emerging role of semaphorins in mediating the crosstalk between tumor cells and multiple stromal cell types in the surrounding microenvironment

Sema3E/Plexin-D1 Mediated Epithelial-to-Mesenchymal Transition in Ovarian Endometrioid Cancer

Cancer cells often employ developmental cues for advantageous growth and metastasis. Here, we report that an axon guidance molecule, Sema3E, is highly expressed in human high-grade ovarian endometrioid carcinoma, but not low-grade or other ovarian epithelial tumors, and facilitates tumor progression. Unlike its known angiogenic activity, Sema3E acted through Plexin-D1 receptors to augment cell migratory ability and concomitant epithelial-to-mesenchymal transition (EMT). Sema3E-induced EMT in ovarian endometrioid cancer cells was dependent on nuclear localization of Snail1 through activation of phosphatidylinositol-3-kinase and ERK/MAPK. RNAi-mediated knockdown of Sema3E, Plexin-D1 or Snail1 in Sema3E-expressing tumor cells resulted in compromised cell motility, concurrent reversion of EMT and diminished nuclear localization of Snail1. By contrast, forced retention of Snail1 within the nucleus of Sema3E-negative tumor cells induced EMT and enhanced cell motility. These results show that in addition to the angiogenic effects of Sema3E on tumor vascular endothelium, an EMT strategy could be exploited by Sema3E/Plexin-D1 signaling in tumor cells to promote cellular invasion/migration

Twist1 Directly Regulates Genes That Promote Cell Proliferation and Migration in Developing Heart Valves

Twist1, a basic helix-loop-helix transcription factor, is expressed in mesenchymal precursor populations during embryogenesis and in metastatic cancer cells. In the developing heart, Twist1 is highly expressed in endocardial cushion (ECC) valve mesenchymal cells and is down regulated during valve differentiation and remodeling. Previous studies demonstrated that Twist1 promotes cell proliferation, migration, and expression of primitive extracellular matrix (ECM) molecules in ECC mesenchymal cells. Furthermore, Twist1 expression is induced in human pediatric and adult diseased heart valves. However, the Twist1 downstream target genes that mediate increased cell proliferation and migration during early heart valve development remain largely unknown. Candidate gene and global gene profiling approaches were used to identify transcriptional targets of Twist1 during heart valve development. Candidate target genes were analyzed for evolutionarily conserved regions (ECRs) containing E-box consensus sequences that are potential Twist1 binding sites. ECRs containing conserved E-box sequences were identified for Twist1 responsive genes Tbx20, Cdh11, Sema3C, Rab39b, and Gadd45a. Twist1 binding to these sequences in vivo was determined by chromatin immunoprecipitation (ChIP) assays, and binding was detected in ECCs but not late stage remodeling valves. In addition identified Twist1 target genes are highly expressed in ECCs and have reduced expression during heart valve remodeling in vivo, which is consistent with the expression pattern of Twist1. Together these analyses identify multiple new genes involved in cell proliferation and migration that are differentially expressed in the developing heart valves, are responsive to Twist1 transcriptional function, and contain Twist1-responsive regulatory sequences

Melanoma Spheroids Grown Under Neural Crest Cell Conditions Are Highly Plastic Migratory/Invasive Tumor Cells Endowed with Immunomodulator Function

International audienceBACKGROUND: The aggressiveness of melanoma tumors is likely to rely on their well-recognized heterogeneity and plasticity. Melanoma comprises multi-subpopulations of cancer cells some of which may possess stem cell-like properties. Although useful, the sphere-formation assay to identify stem cell-like or tumor initiating cell subpopulations in melanoma has been challenged, and it is unclear if this model can predict a functional phenotype associated with aggressive tumor cells. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed the molecular and functional phenotypes of melanoma spheroids formed in neural crest cell medium. Whether from metastatic or advanced primary tumors, spheroid cells expressed melanoma-associated markers. They displayed higher capacity to differentiate along mesenchymal lineages and enhanced expression of SOX2, NANOG, KLF4, and/or OCT4 transcription factors, but not enhanced self-renewal or tumorigenicity when compared to their adherent counterparts. Gene expression profiling attributed a neural crest cell signature to these spheroids and indicated that a migratory/invasive and immune-function modulating program could be associated with these cells. In vitro assays confirmed that spheroids display enhanced migratory/invasive capacities. In immune activation assays, spheroid cells elicited a poorer allogenic response from immune cells and inhibited mitogen-dependent T cells activation and proliferation more efficiently than their adherent counterparts. Our findings reveal a novel immune-modulator function of melanoma spheroids and suggest specific roles for spheroids in invasion and in evasion of antitumor immunity. CONCLUSION/SIGNIFICANCE: The association of a more plastic, invasive and evasive, thus a more aggressive tumor phenotype with melanoma spheroids reveals a previously unrecognized aspect of tumor cells expanded as spheroid cultures. While of limited efficiency for melanoma initiating cell identification, our melanoma spheroid model predicted aggressive phenotype and suggested that aggressiveness and heterogeneity of melanoma tumors can be supported by subpopulations other than cancer stem cells. Therefore, it could be constructive to investigate melanoma aggressiveness, relevant to patients and clinical transferability

How do cardiologists select patients for dual antiplatelet therapy continuation beyond 1 year after a myocardial infarction? Insights from the EYESHOT Post-MI Study

Background: Current guidelines suggest to consider dual antiplatelet therapy (DAPT) continuation for longer than 12 months in selected patients with myocardial infarction (MI). Hypothesis: We sought to assess the criteria used by cardiologists in daily practice to select patients with a history of MI eligible for DAPT continuation beyond 1 year. Methods: We analyzed data from the EYESHOT Post-MI, a prospective, observational, nationwide study aimed to evaluate the management of patients presenting to cardiologists 1 to 3 years from the last MI event. Results: Out of the 1633 post-MI patients enrolled in the study between March and December 2017, 557 (34.1%) were on DAPT at the time of enrolment, and 450 (27.6%) were prescribed DAPT after cardiologist assessment. At multivariate analyses, a percutaneous coronary intervention (PCI) with multiple stents and the presence of peripheral artery disease (PAD) resulted as independent predictors of DAPT continuation, while atrial fibrillation was the only independent predictor of DAPT interruption for patients both at the second and the third year from MI at enrolment and the time of discharge/end of the visit. Conclusions: Risk scores recommended by current guidelines for guiding decisions on DAPT duration are underused and misused in clinical practice. A PCI with multiple stents and a history of PAD resulted as the clinical variables more frequently associated with DAPT continuation beyond 1 year from the index MI

Determinants of worse liver‐related outcome according to HDV infection among HBsAg positive persons living with HIV: Data from the ICONA cohort

Objectives: We aimed to study hepatitis D virus (HDV) prevalence and risk of progression to severe liver-related events (SLRE) in HBsAg positive people living with HIV (PLWH) in Italy; role of HDV-RNA copy levels, HCV coinfection and nadir CD4 counts were also investigated.Methods: People living with HIV (PLWH) from Italian Foundation cohort Naive antiretrovirals (ICONA) with available HBsAg and HDV Ab were enrolled. HBsAg, HDV Ab, HDV-RNA and HDV genotypes were tested. Primary end-point: time from first HDV screening to Severe Liver Related Events (SLRE: decompensated cirrhosis, liver transplantation, HCC). Fine-grey regression models were used to evaluate the association of HDV Ab, HDV-RNA, HDV/HCV coinfection, CD4 nadir and outcome. Secondary end-points: time to SLRE or death; HDV Ab and HDV-RNA prevalence.Results: A total of 152/809 (18.8%) HBsAg positive PLWH showed HDV Ab reactivity; 63/93 (67.7%) were HDV-RNA positive. Being male, persons who inject drugs (PWID), HCV Ab positive, with FIB-4 > 3.25 were independent factors of HDV Ab positivity. In a median follow-up of 5 years, 37 PLWH (4.1% at 5-year) developed SLRE and 97 (12.0%) reached the SLRE or death end-point. HDV-RNA positive (independently from HDV-RNA copy level) PLWH had a 4.6-fold (95%CI 2.0-10.5) higher risk of SLRE than HDV negatives. PLWH positive for both HCV Ab and HDV Ab showed the highest independent risk of SLRE (ASHR: 11.9, 95%CI: 4.6-30.9 vs. HCV neg/HDV neg). Nadir CD4 < 200/mL was associated with SLRE (ASHR: 3.9, 95% 1.0-14.5).Conclusions: One-fifth of the HBsAg positive PLWH harbour HDV infection, and are at high risk of progression to advanced liver disease. HCV contributes to worse outcomes. This population needs urgently effective treatments

Is HCV elimination among persons living with HIV feasible? Data from the NoCo study in the setting of the ICONA cohort

Background and aims: Whether the HCV test-and-treat strategy impacted on the rate of new HCV infections among PLWH in Italy is unknown. Methods: Prospective study of PLWH in the ICONA network. At baseline, PLWH were tested for HCV-Ab; HCV-RNA (if HCV-Ab positive) and, if positive, treated with DAA. SVR12 indicated eradication. Seroconversions and re-infections were evaluated yearly in HCV-Ab neg and HCV-RNA neg at first screening. We estimated the following: HCV seroconversions, incidence of HCV reinfections, and access to DAA and SVR12 rates tighter with factors associated with each outcome. Data were analysed by Cox regression, Poisson regression and logistic regression models. Results: Sixteen thousand seven hundred and forty-three PLWH were included; 27.3% HCV-Ab positive; of these, 39.3% HCV-RNA positive. HCV seroconversion incidence: .48/100 PYFU (95% CI: .36-.65); re-infections incidence: 1.40/100 PYFU (95% CI: .91-2.04). The risk factor for HCV re-infection was young age: aIRR 1.85, 95% CI: 1.17-2.95) per 10 years younger. 86.4% of HCV viremic in follow-up started DAA. PWID vs. heterosexuals (aHR .75, 95% CI .62-.90), HIV-RNA >50 copies/mL (aHR .70, 95% CI .56-.87), HCV genotype other than G1, G2, G3, G4 or with multiple/missing HCV genotype and post-COVID-19 calendar periods were associated with lower DAA access. 922/965 (95.5%) PLWH achieved SVR12. We estimated 72% reduction of chance to achieve SVR12 in PLWH with a CD4 count <200/mm3 (vs. CD4 ≥200/mm3 aOR .18, 95% CI: .07-.46). 95.5% of DAA-treated individuals eradicated HCV, but they represent only 53.2% of HCV viremic PLWH and 66.4% of those in follow-up. HCV-RNA positivity by year decreased from 41.7% in 2017 to 11.7% in 2022. Conclusions: The screening-and-treat campaign implemented in Italy, even if only partially effective, resulted in a dramatic drop in HCV circulation in our cohort

Cancer Biomarker Discovery: The Entropic Hallmark

Background: It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods. Methodology/Principal Findings: Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer. Conclusions/Significance: We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-throughput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases