64 research outputs found
CD20-Mimotope Peptides: A Model to Define the Molecular Basis of Epitope Spreading
No full textAntigen-mimicking peptide (mimotope)-based vaccines are one of the most promising forms of active-immunotherapy. The main drawback of this approach is that it induces antibodies that react poorly with the nominal antigen. The aim of this study was to investigate the molecular basis underlying the weak antibody response induced against the naïve protein after peptide vaccination. For this purpose, we analyzed the fine specificity of monoclonal antibodies (mAb) elicited with a 13-mer linear peptide, complementary to theantigen-combining site of the anti-CD20 mAb, Rituximab, in BALB/c mice. Anti-peptide mAb competed with Rituximab for peptide binding. Even so, they recognized a different antigenic motif from the one recognized by Rituximab. This explains their lack of reactivity with membrane (naïve) CD20. These data indicate that even on a short peptide the immunogenic and antigenic motifs may be different. These findings highlight an additional mechanism for epitope spreading and should be taken into account when designing peptides for vaccine purposes
Beyond APECED: An update on the role of the autoimmune regulator gene (AIRE) in physiology and disease
No full textpeer reviewedThe autoimmune regulator gene (AIRE) is a transcription factor expressed both in the thymus, by medullary thymic epithelial cells, and in secondary lymphoid organs. AIRE controls the local transcription of organ- specific proteins typically expressed in peripheral tissues, thus allowing the negative selection of self- reactive T cells. The crucial role played by AIRE in central immune tolerance emerged in the studies on the pathogenesis of Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy, a rare inherited polyendocrine/autoimmune disease. Thereafter, several studies found evidences indicating that AIRE impairment might be pathogenically involved in several autoimmune diseases and in tumorigenesis. In this review, we focus on recent advances relative to AIRE's effect on T cell development in physiology and disease. In particular, we address the following issues: 1) AIRE function and mTECs biology, 2) the impact of AIRE gene mutations in autoimmune diseases, and 3) the role of AIRE gene in anti-tumor immune response. © 2018 Elsevier B.V
Androgen receptor, PARP signaling, and tumor microenvironment: the ‘perfect triad’ in prostate cancer?
No full textAberrations in the homologous recombination repair (HRR) pathway in prostate cancer (PCa) provide a unique opportunity to develop therapeutic strategies that take advantage of the reduced tumor ability to repair DNA damage. Poly-ADP-ribose polymerase (PARP) inhibitors (PARPi) have been shown to prolong the survival of PCa patients with HRR defects, particularly in those with Breast Cancer type 1 susceptibility protein/Breast Cancer type 2 susceptibility protein alterations. To expand the benefit of PARPi to patients without detectable HRR alterations, multiple preclinical and clinical studies are addressing potential synergies between PARPi and androgen receptor signaling inhibitors, and these strategies are also being evaluated in combination with other drugs such as immune checkpoint inhibitors. However, the effectiveness of these combining therapies could be hindered by multiple mechanisms of resistance, including also the role played by the immunosuppressive tumor microenvironment. In this review, we summarize the use of PARPi in PCa and the potential synergies with different molecular pathways. However, numerous unanswered questions remain, including the identification of the patient population that could benefit most from PARPi, determining whether to use PARPi as monotherapy or in combination, and finding the optimal timing of PARPi, expanding the use of genomic tests, and optimizing combination therapies
Circulating Tumor DNA: A New Research Frontier in Urological Oncology from Localized to Metastatic Disease
No full textBackground and objective: Circulating tumor DNA (ctDNA) testing provides valuable prognostic and predictive information for guiding therapeutic choices and monitoring disease progression and drug resistance for urological tumors. Our review focuses on emerging opportunities for ctDNA analysis in urological tumors and the development of potential circulating biomarkers within a multidisciplinary framework to improve personalized treatment. Methods: A nonsystematic literature review was conducted in the PubMed and MEDLINE databases. Prospective and retrospective peer-reviewed studies, review articles, and research abstracts on the use of ctDNA for urological tumors were included. Key findings and limitations: Several studies have demonstrated that ctDNA analysis is a promising tool that can help clinicians in the diagnosis and clinical management of urological tumors. In prostate and urothelial cancers, the ctDNA fraction increases proportionally from localized to metastatic disease, indicating a higher tumor burden and more aggressive behavior. Thus, ctDNA seems to be a useful tool for improving prognostic risk stratification and treatment selection. Data on the use of liquid biopsy in renal cell carcinoma are still limited, and assessment of prognostic and predictive biomarkers is a critical unmet need. Conclusions and clinical implications: ctDNA analysis promises to revolutionize the management of urological tumors in different disease settings. Integration of ctDNA testing in routine clinical practice will require a multidisciplinary approach that involve patients, clinicians, and molecular biologists. Patient summary: We reviewed how testing for tumor DNA in blood (circulating tumor DNA, ctDNA) is used in urological cancers. A great deal of evidence supports the usefulness of this noninvasive test. However, further research via a multidisciplinary approach is needed before ctDNA testing becomes part of routine patient care
Identification of alternative transcripts of NSD1 gene in Sotos Syndrome patients and healthy subjects
No full textNSD1 gene (Nuclear Receptor Binding SET Domain Protein 1) encodes a methyltransferase that plays an important role in embryonic development. NSD1 is implicated in the transcription and methylation of histone H3 at lysine 36 (H3-K36), but the molecular mechanisms involved in these processes remain largely unknown. Pathogenic variants of NSD1 gene lead to Sotos syndrome, and have also been detected in some type of cancers, such as acute myeloid leukemia. In this study we have investigated NSD1 mRNA expression in fibroblast cell lines obtained from 14 Sotos patients and from 8 healthy controls. In addition to the expected NSD1 canonical transcript (isoform 1), we identified two additional, not yet reported, short NSD1 mRNA isoforms: NSD1 Delta 5 Delta 7 (isoform 2) and NSD1 Delta 19-23 (isoform 3), both in healthy subjects and in Sotos patients. We also show that NSD1 mutations in patients can be associated with a decreased level of NSD1 mRNA, as expected. Moreover, one patient, bearing the NSD1 variant c.6010-10G > A, expressed an additional shorter transcript derived from an aberrant splicing event. These results may provide a basis to elucidate the impact of different NSD1 pathogenic variants on the het-erogeneity of phenotype associated with Sotos syndrome
Indoleamine 2,3 dioxygenase gene polymorphisms correlate with CD8+ Treg impairment in systemic sclerosis.
No full textRole of AIRE gene in melanoma
No full textPolymorphisms of AIRE, a transcription factor that up-regulates intrathymic expression of tissue-specific antigens including melanoma-associated antigens (MAAs), may variably affect the selection of MAAs-specific thymocytes, generating T-cell repertoires protecting or predisposing individuals to melanoma. We found that AIRE single nucleotide polymorphisms (SNPs) rs1055311, rs1800520 and rs1800522 were significantly more frequent in healthy subjects than in melanoma patients, independently from sex, age and stages of melanoma. The presence of these SNPs was associated with increased frequency of two T-cell clonotypes specific for MAGE-1 linking their protective effect to selection/expansion of MAA-specific T cells. Interestingly, mRNA transcribed on the rs1800520 SNP showed increased free energy than the wild type suggesting that its reduced stability may be responsible for the different activity of the polymorphic AIRE molecule. This finding may contribute at identifying subjects with increased risk of developing melanoma or patients with melanoma that may take benefit from immunotherapy.AIRE nel melanom
The role of AIRE polymorphisms in melanoma.
No full textpeer reviewedPolymorphisms of AIRE, a transcription factor that up-regulates intrathymic expression of tissue-specific antigens including melanoma-associated antigens (MAAs), may variably affect the selection of MAAs-specific thymocytes, generating T-cell repertoires protecting or predisposing individuals to melanoma. We found that AIRE single nucleotide polymorphisms (SNPs) rs1055311, rs1800520 and rs1800522 were significantly more frequent in healthy subjects than in melanoma patients, independently from sex, age and stages of melanoma. The presence of these SNPs was associated with increased frequency of two T-cell clonotypes specific for MAGE-1 linking their protective effect to selection/expansion of MAA-specific T cells. Interestingly, mRNA transcribed on the rs1800520 SNP showed increased free energy than the wild type suggesting that its reduced stability may be responsible for the different activity of the polymorphic AIRE molecule. This finding may contribute at identifying subjects with increased risk of developing melanoma or patients with melanoma that may take benefit from immunotherapy.AIRE in melanom
Cyclophosphamide inhibits the generation and function of CD8(+) regulatory T cells
No full textpeer reviewedCD8(+) regulatory T cells (Treg) and CD4(+)CD25(+) Treg infiltrate human cancers, thus favoring tumor immune escape. Therefore, in the setting of antitumor therapeutic protocols, it is important to associate antitumor treatment with agents that are able to inhibit Treg function. Cyclophosphamide (CY) has been demonstrated to be effective in counteracting CD4(+)CD25(+) Treg activity. Hence, we tested its inhibitory efficacy on human CD8(+) Treg. Because CY is a prodrug, 4-hydroperoxycyclophosphamide (4-HC), a derivative of CY that in aqueous solution is converted to 4-hydroxycyclophosphamide, an active metabolite of CY, was used. 4-HC significantly inhibited CD8(+) Treg generation and function but only at the higher tested concentration (0.5 μg/mL), that is, in the therapeutic range of the drug. The lower 4-HC concentration tested (0.1 μg/mL) was almost ineffective. 4-HC inhibitory effects were related to apoptosis/necrosis induction. When CD8(+)CD28(+) non-Treg were analyzed for comparative purposes, significantly lower cytotoxic rates among these cells were observed than among CD8(+) Treg, which were differentiated because they did not express the CD28 molecule. These data demonstrate that CD8(+) Treg are inhibited through cytotoxic phenomena by CY, thus supporting the use of this drug at adequate concentrations and schedules of administration as a Treg inhibitor in combinatorial chemo- or immunotherapeutic anticancer protocols.Cyclophosphamide impact on CD8+ Tre
Different and synergistic effect of 5-Azacytidine and Rapamycin on ex vivo expansion of natural human T Regulatory cells
No full textNatural T regulatory cells (Treg) are challenging to expand ex vivo, and this has severely hindered in vivo evaluation of their therapeutic potential. 5-Azacytidine (5-azaC) and Rapamycin (RAPA) are immunosuppressive drugs that promote selectively the expansion of CD4+CD25highFoxp3+ regulatory T cells. We investigated whether 5-azaC and RAPA could be used together to promote the ex vivo expansion of Tregs purified from adult human peripheral blood.
: We found that 5-azaC helped maintain FOXP3 expression during the expansion process probably by promoting the conversion of T conventional (Tconv) in Treg, instead Rapa induces selectively apoptosis in Tconv cells and expansion in Treg. Addition of 5-azaC to RAPA treated cultures improved gene expression of FOXP3, CD25, STAT5 and TGF-B resulted in enhanced Treg expansion and suppressive activity. Also Rapa and 5-AzaC combination sustain Bcl-2 protein expression in Treg conferring resistance to apoptosis process. 5-azaC may have utility in ex vivo expansion of human Tregs, not as a single agent, but in combination with RAPA. These data may considerably accelerate the development of immunotherapeutic approaches for the treatment of autoimmune disease or posttransplant alloreactions by the adoptive transfer of nTreg cells
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