Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
51 result(s) for "Santamaria, Gianluca"
Sort by:
MicroRNA let-7g acts as tumor suppressor and predictive biomarker for chemoresistance in human epithelial ovarian cancer
Remarkable deregulation of microRNAs has been demonstrated in epithelial ovarian cancer (EOC). In particular, some of the let-7 miRNA family members have been proposed as tumor suppressors. Here, we explored the functional roles of let-7g in EOC. The ectopic overexpression of let-7g in OVCAR3 and HEY-A8 EOC cells induced i) a down-regulation of c-Myc and cyclin-D2 thus promoting cell cycle arrest, ii) a reduction of Vimentin, Snail and Slug thus counteracting the progression of epithelial to mesenchymal transition, iii) a chemosensitization to cis -platinum treatment. Next, analysis of human EOC tissues revealed that let-7g expression was significantly reduced in tumor tissue specimens of patients with EOC compared to their non-tumor counterparts ( p  = 0.0002). Notably, low let-7g tissue levels were significantly associated with acquired chemoresistance of patients with late-stage of EOC (n = 17, p  = 0.03194). This finding was further validated in the serum samples collected from the same cohort of patients (n = 17, p  = 0.003). To conclude, we demonstrate that let-7g acts as tumor suppressor and might be used to disable EOC tumor progression and chemoresistance to cis -platinum-based chemotherapy. Furthermore, we propose that decreased expression of let-7g could serve as a tissue and serum biomarker able to predict the chemo-resistant features of EOC patients.
Multifunctional Aptamer-miRNA Conjugates for Targeted Cancer Therapy
While microRNAs (miRNAs) clearly regulate multiple pathways integral to disease development and progression, the lack of safe and reliable means for specific delivery of miRNAs to target tissues represents a major obstacle to their broad therapeutic application. Our objective was to explore the use of nucleic acid aptamers as carriers for cell-targeted delivery of a miRNA with tumor suppressor function, let-7g. Using an aptamer that binds to and antagonizes the oncogenic receptor tyrosine kinase Axl (GL21.T), here we describe the development of aptamer-miRNA conjugates as multifunctional molecules that inhibit the growth of Axl-expressing tumors. We conjugated the let-7g miRNA to GL21.T and demonstrate selective delivery to target cells, processing by the RNA interference machinery, and silencing of let-7g target genes. Importantly, the multifunctional conjugate reduced tumor growth in a xenograft model of lung adenocarcinoma. Therefore, our data establish aptamer-miRNA conjugates as a novel tool for targeted delivery of miRNAs with therapeutic potential.
SOX2 promotes a cancer stem cell-like phenotype and local spreading in oral squamous cell carcinoma
Emerging evidence shows that oral squamous cell carcinoma (OSCC) invasiveness can be attributed to a small subpopulation of cancer stem cells (CSCs) in the bulk of the tumor. However, the presence of CSCs in the OSCC close resection margins is still poorly unexplored. Here, we found that BMI1 , CD44 , SOX2 , OCT4 , UBE2C , CXCR4 CSCs marker genes are significantly upregulated, while IGF1-R , KLF4 , ALDH1A1 , CD133 , FAM3C are downregulated in the tumor core vs healthy mucosa of 24 patients with OSCC. Among these, SOX2 appears also upregulated in the tumor close margin vs healthy mucosa and this significantly correlates with tumor size and lymph node compromise. In vitro analyses in CAL27 and SCC15 tongue squamous cell carcinoma cell lines, show that SOX2 transient knockdown i) promotes the mesenchymal-to-epithelial transition, ii) smooths the invasiveness, iii) attenuates the 3D tumor sphere-forming capacity, and iv) partially increases the sensitivity to cisplatin treatment. Overall, our study highlights that the OSCC close margins can retain CSC-specific markers. Notably, SOX2 may represent a useful CSCs marker to predict a more aggressive phenotype and a suitable target to prevent local invasiveness.
Retinoic acid signaling modulation guides in vitro specification of human heart field-specific progenitor pools
Cardiogenesis relies on the precise spatiotemporal coordination of multiple progenitor populations. Understanding the specification and differentiation of these distinct progenitor pools during human embryonic development is crucial for advancing our knowledge of congenital cardiac malformations and designing new regenerative therapies. By combining genetic labelling, single-cell transcriptomics, and ex vivo human-mouse embryonic chimeras we uncovered that modulation of retinoic acid signaling instructs human pluripotent stem cells to form heart field-specific progenitors with distinct fate potentials. In addition to the classical first and second heart fields, we observed the appearance of juxta-cardiac field progenitors giving rise to both myocardial and epicardial cells. Applying these findings to stem-cell based disease modelling we identified specific transcriptional dysregulation in first and second heart field progenitors derived from stem cells of patients with hypoplastic left heart syndrome. This highlights the suitability of our in vitro differentiation platform for studying human cardiac development and disease. The heart is formed from several spatiotemporally distinct progenitor pools during development. Here they show that modulation of retinoic acid signaling can instruct human pluripotent stems cells into heart progenitors that are useful for studying human development and disease.
ALDOC- and ENO2- driven glucose metabolism sustains 3D tumor spheroids growth regardless of nutrient environmental conditions: a multi-omics analysis
Background Metastases are the major cause of cancer-related morbidity and mortality. By the time cancer cells detach from their primary site to eventually spread to distant sites, they need to acquire the ability to survive in non-adherent conditions and to proliferate within a new microenvironment in spite of stressing conditions that may severely constrain the metastatic process. In this study, we gained insight into the molecular mechanisms allowing cancer cells to survive and proliferate in an anchorage-independent manner, regardless of both tumor-intrinsic variables and nutrient culture conditions. Methods 3D spheroids derived from lung adenocarcinoma (LUAD) and breast cancer cells were cultured in either nutrient-rich or -restricted culture conditions. A multi-omics approach, including transcriptomics, proteomics, and metabolomics, was used to explore the molecular changes underlying the transition from 2 to 3D cultures. Small interfering RNA-mediated loss of function assays were used to validate the role of the identified differentially expressed genes and proteins in H460 and HCC827 LUAD as well as in MCF7 and T47D breast cancer cell lines. Results We found that the transition from 2 to 3D cultures of H460 and MCF7 cells is associated with significant changes in the expression of genes and proteins involved in metabolic reprogramming. In particular, we observed that 3D tumor spheroid growth implies the overexpression of ALDOC and ENO2 glycolytic enzymes concomitant with the enhanced consumption of glucose and fructose and the enhanced production of lactate. Transfection with siRNA against both ALDOC and ENO2 determined a significant reduction in lactate production, viability and size of 3D tumor spheroids produced by H460, HCC827, MCF7, and T47D cell lines. Conclusions Our results show that anchorage-independent survival and growth of cancer cells are supported by changes in genes and proteins that drive glucose metabolism towards an enhanced lactate production. Notably, this finding is valid for all lung and breast cancer cell lines we have analyzed in different nutrient environmental conditions. broader Validation of this mechanism in other cancer cells of different origin will be necessary to broaden the role of ALDOC and ENO2 to other tumor types. Future in vivo studies will be necessary to assess the role of ALDOC and ENO2 in cancer metastasis.
Distinctive chromosomal, mutational and transcriptional profiling in colon versus rectal cancers
Background Colorectal cancer (CRC) encompasses tumors arising in the colon (CC) and rectum (RC), often treated as a single disease despite emerging evidence of biological divergence. Understanding the molecular differences between CC and RC is critical for improving diagnosis, prognosis, and therapeutic strategies. Methods We performed an integrated genomic and transcriptomic analysis of CC and RC data from The Cancer Genome Atlas (TCGA) to investigate their degree of similarity and observed that these tumors present distinct molecular profiles, which suggest an evolution through divergent pathways. Comparative analyses included copy number alterations (CNAs), somatic mutations, driver gene prediction, differential gene expression, pathway enrichment, and survival analysis. Results Chromosomal analyses revealed that 43% of focal and 77% of large-scale CNAs were specific of CC, while 10.5% and 57% were specific of RC with 8% of mutant genes unique to CC and 0.18% to RC. CC and RC presented distinct profiles of gene mutations, with CC showing significantly higher tumor mutational burden (0.51 muts/Mb vs 0.28 muts/Mb in RC). Distinct mutational signatures were identified, with CC characterized by a higher frequency of PIK3CA , BRAF , and DNAH1 mutations, while RC showed enrichment for TP53 and NRAS mutations. Importantly, analysis of predicted non-canonical driver genes identified ACVR1B , LTBP4 , SETD1A as CC-specific drivers and C4BPA , EHD1 as RC-specific drivers, underscoring divergent oncogenic mechanisms. However, the most substantial divergence was observed in transcriptomic profiling, with 56% and 33% of DEGs (in CC and RC, respectively) that were tumor-type specific. Notably, RC tumors segregated into two distinct transcriptional subtypes (Cluster 1 and Cluster 2), with Cluster 1 showed a more heterogeneous Consensus Molecular Subtypes (CMS) distribution, while Cluster 2 enriched in CMS4 (mesenchymal) and CMS3 (metabolic) consensus molecular subtypes. Accordingly, Gene Set Enrichment Analysis revealed CC-specific upregulation of Wnt, MYC, and mTOR signaling pathways, and RC-specific enrichment of GPCR and neuronal development pathways. On the other hand, pseudogene expression was significantly higher in CC, suggesting differential mechanisms of transcriptional dysregulation. Finally, we identified an RC-specific multigene survival signature as a prognostic model involving upregulation of C2CD4B , HSPD1P1 , LINC01356 , CBX3P9 , GATA2-AS1 and downregulation of ATP5F1EP2 , HSP90AB3P and SNRPFP1 . Conclusions Collectively, our findings provide robust molecular evidence that CC and RC follow divergent oncogenic pathways, emphasizing the need for site-specific biomarker development and therapeutic targeting in colorectal cancer.
C-Kit Is Essential for Vascular Smooth Muscle Cell Phenotypic Switch In Vitro and In Vivo After Injury
Pathological vascular remodeling—central to restenosis, atherosclerosis, and vasculo-proliferative diseases—depends on the phenotypic switching of vascular smooth muscle cells (VSMCs) from a quiescent, contractile state to a synthetic, proliferative program. Although the receptor tyrosine kinase c-Kit is implicated in proliferation, migration, and tissue repair, its role in VSMC plasticity has yet to be fully understood. Using c-Kit haploinsufficient mice subjected to right carotid artery ligation (CAL) and primary aortic VSMC cultures, we show that c-Kit is required for the contractile-to-synthetic transition. In vitro, c-Kit haploinsufficiency halved c-Kit expression, reduced 5-bromo-2′-deoxyuridine (BrdU) incorporation, and blunted platelet-derived growth factor BB (PDGF-BB)-induced repression of contractile genes. c-Kit–deficient VSMCs exhibited a senescence program with increased p16INK4a/p21 expression and upregulated senescence-associated secretory phenotype (SASP) mediators. RNA-Seq of carotid arteries 7 days post-ligation revealed that wild-type arteries activated cell-cycle pathways and suppressed contractile signatures, whereas c-Kit-deficient carotid arteries failed to fully engage proliferative programs and instead maintained contractile gene expression. At 28 days post CAL in vivo, c-Kit haploinsufficiency produced markedly reduced neointima, fewer Ki67+ VSMCs, more p16INK4a+ cells, and impaired re-endothelialization. Because progenitor-to-VSMC differentiation contributes to remodeling, we tested adult cardiac stem/progenitor cells (CSCs) as a model system of adult progenitor differentiation. Wild-type CSCs efficiently generated induced VSMCs (iVSMCs) with appropriate smooth-muscle gene upregulation; c-Kit–deficient rarely did so. Restoring c-Kit with a BAC transgene rescued both the smooth-muscle differentiation and proliferative competence of c-Kit-deficient iVSMCs. Collectively, our data identified c-Kit as a gatekeeper of reparative VSMC plasticity. Adequate c-Kit enables progenitor-to-VSMC commitment and the expansion of newly formed VSMCs while permitting injury-induced proliferation and matrix synthesis; reduced c-Kit locks cells in a hypercontractile, senescence-prone state and limits neointima formation. Modulating the c-Kit axis may therefore offer a strategy to fine-tune vascular repair while mitigating pathological remodeling.
Functional abnormalities in induced Pluripotent Stem Cell-derived cardiomyocytes generated from titin-mutated patients with dilated cardiomyopathy
Dilated cardiomyopathy (DCM), a myocardial disorder that can result in progressive heart failure and arrhythmias, is defined by ventricular chamber enlargement and dilatation, and systolic dysfunction. Despite extensive research, the pathological mechanisms of DCM are unclear mainly due to numerous mutations in different gene families resulting in the same outcome-decreased ventricular function. Titin (TTN)-a giant protein, expressed in cardiac and skeletal muscles, is an important part of the sarcomere, and thus TTN mutations are the most common cause of adult DCM. To decipher the basis for the cardiac pathology in titin-mutated patients, we investigated the hypothesis that induced Pluripotent Stem Cell (iPSC)-derived cardiomyocytes (iPSC-CM) generated from patients, recapitulate the disease phenotype. The hypothesis was tested by 3 Aims: (1) Investigate key features of the excitation-contraction-coupling machinery; (2) Investigate the responsiveness to positive inotropic interventions; (3) Investigate the proteome profile of the AuP cardiomyocytes using mass-spectrometry (MS). iPSC were generated from the patients' skin fibroblasts. The major findings were: (1) Sarcomeric organization analysis in mutated iPSC-CM showed defects in assembly and maintenance of sarcomeric structure. (2) Mutated iPSC-CM exhibited diminished inotropic and lusitropic responses to β-adrenergic stimulation with isoproterenol, increased [Ca2+]out and angiotensin-II. Additionally, mutated iPSC-CM displayed prolonged recovery in response to caffeine. These findings may result from defective or lack of interactions of the sarcomeric components with titin through its kinase domain which is absent in the mutated cells. These findings show that the mutated cardiomyocytes from DCM patients recapitulate abnormalities of the inherited cardiomyopathies, expressed as blunted inotropic response.
Contribution of hypoxia-inducible factor 1alpha to pathogenesis of sarcomeric hypertrophic cardiomyopathy
Hypertrophic cardiomyopathy (HCM) caused by autosomal-dominant mutations in genes coding for structural sarcomeric proteins, is the most common inherited heart disease. HCM is associated with myocardial hypertrophy, fibrosis and ventricular dysfunction. Hypoxia-inducible transcription factor-1α (Hif-1α) is the central master regulators of cellular hypoxia response and associated with HCM. Yet its exact role remains to be elucidated. Therefore, the effect of a cardiomyocyte-specific Hif-1a knockout (cHif1aKO) was studied in an established α-MHC 719/+ HCM mouse model that exhibits the classical features of human HCM. The results show that Hif-1α protein and HIF targets were upregulated in left ventricular tissue of α-MHC 719/+ mice. Cardiomyocyte-specific abolishment of Hif-1a blunted the disease phenotype, as evidenced by decreased left ventricular wall thickness, reduced myocardial fibrosis, disordered SRX/DRX state and ROS production. cHif1aKO induced normalization of pro-hypertrophic and pro-fibrotic left ventricular remodeling signaling evidenced on whole transcriptome and proteomics analysis in α-MHC 719/+ mice. Proteomics of serum samples from patients with early onset HCM revealed significant modulation of HIF. These results demonstrate that HIF signaling is involved in mouse and human HCM pathogenesis. Cardiomyocyte-specific knockout of Hif-1a attenuates disease phenotype in the mouse model. Targeting Hif-1α might serve as a therapeutic option to mitigate HCM disease progression.
The Spread of SARS-CoV-2 Omicron Variant in CALABRIA: A Spatio-Temporal Report of Viral Genome Evolution
We investigated the evolution of SARS-CoV-2 spread in Calabria, Southern Italy, in 2022. A total of 272 RNA isolates from nasopharyngeal swabs of individuals infected with SARS-CoV-2 were sequenced by whole genome sequencing (N = 172) and/or Sanger sequencing (N = 100). Analysis of diffusion of Omicron variants in Calabria revealed the prevalence of 10 different sub-lineages (recombinant BA.1/BA.2, BA.1, BA.1.1, BA.2, BA.2.9, BA.2.10, BA.2.12.1, BA.4, BA.5, BE.1). We observed that Omicron spread in Calabria presented a similar trend as in Italy, with some notable exceptions: BA.1 disappeared in April in Calabria but not in the rest of Italy; recombinant BA.1/BA.2 showed higher frequency in Calabria (13%) than in the rest of Italy (0.02%); BA.2.9, BA.4 and BA.5 emerged in Calabria later than in other Italian regions. In addition, Calabria Omicron presented 16 non-canonical mutations in the S protein and 151 non-canonical mutations in non-structural proteins. Most non-canonical mutations in the S protein occurred mainly in BA.5 whereas non-canonical mutations in non-structural or accessory proteins (ORF1ab, ORF3a, ORF8 and N) were identified in BA.2 and BA.5 sub-lineages. In conclusion, the data reported here underscore the importance of monitoring the entire SARS-CoV-2 genome.