RESUMO
Tumors are mostly characterized by genetic instability, as result of mutations in surveillance mechanisms, such as DNA damage checkpoint, DNA repair machinery and mitotic checkpoint. Defect in one or more of these mechanisms causes additive accumulation of mutations. Some of these mutations are drivers of transformation and are positively selected during the evolution of the cancer, giving a growth advantage on the cancer cells. If such mutations would result in mutated neoantigens, these could be actionable targets for cancer vaccines and/or adoptive cell therapies. However, the results of the present analysis show, for the first time, that the most prevalent mutations identified in human cancers do not express mutated neoantigens. The hypothesis is that this is the result of the selection operated by the immune system in the very early stages of tumor development. At that stage, the tumor cells characterized by mutations giving rise to highly antigenic non-self-mutated neoantigens would be efficiently targeted and eliminated. Consequently, the outgrowing tumor cells cannot be controlled by the immune system, with an ultimate growth advantage to form large tumors embedded in an immunosuppressive tumor microenvironment (TME). The outcome of such a negative selection operated by the immune system is that the development of off-the-shelf vaccines, based on shared mutated neoantigens, does not seem to be at hand. This finding represents the first demonstration of the key role of the immune system on shaping the tumor antigen presentation and the implication in the development of antitumor immunological strategies.
Assuntos
Vacinas Anticâncer , Neoplasias , Humanos , Neoplasias/genética , Neoplasias/terapia , Antígenos de Neoplasias/genética , Vacinas Anticâncer/genética , Mutação/genética , Pontos de Checagem do Ciclo Celular , Imunoterapia , Microambiente TumoralRESUMO
BACKGROUND: The development of cancer immunotherapeutic strategies relies on the identification and validation of optimal target tumor antigens, which should be tumor-specific as well as able to elicit a swift and potent anti-tumor immune response. The vast majority of such strategies are based on tumor associated antigens (TAAs) which are shared wild type cellular self-epitopes highly expressed on tumor cells. Indeed, TAAs can be used to develop off-the-shelf cancer vaccines appropriate to all patients affected by the same malignancy. However, given that they may be also presented by HLAs on the surface of non-malignant cells, they may be possibly affected by immunological tolerance or elicit autoimmune responses. MAIN BODY: In order to overcome such limitations, analogue peptides with improved antigenicity and immunogenicity able to elicit a cross-reactive T cell response are needed. To this aim, non-self-antigens derived from microorganisms (MoAs) may be of great benefit.
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Vacinas Anticâncer , Neoplasias , Humanos , Mimetismo Molecular , Neoplasias/tratamento farmacológico , Antígenos de Neoplasias , Linfócitos TRESUMO
BACKGROUND: The gut microbiota profile is unique for each individual and are composed by different bacteria species according to individual birth-to-infant transitions. In the last years, the local and systemic effects of microbiota on cancer onset, progression and response to treatments, such as immunotherapies, has been extensively described. Here we offer a new perspective, proposing a role for the microbiota based on the molecular mimicry of tumor associated antigens by microbiome-associated antigens. METHODS: In the present study we looked for homology between published TAAs and non-self microbiota-derived epitopes. Blast search for sequence homology was combined with extensive bioinformatics analyses. RESULTS: Several evidences for homology between TAAs and microbiota-derived antigens have been found. Strikingly, three cases of 100% homology between the paired sequences has been identified. The predicted average affinity to HLA molecules of microbiota-derived antigens is very high (< 100 nM). The structural conformation of the microbiota-derived epitopes is, in general, highly similar to the corresponding TAA. In some cases, it is identical and contact areas with both HLA and TCR chains are indistinguishable. Moreover, the spatial conformation of TCR-facing residues can be identical in paired TAA and microbiota-derived epitopes, with exactly the same values of planar as well as dihedral angles. CONCLUSIONS: The data reported in the present study show for the first time the high homology in the linear sequence as well as in structure and conformation between TAAs and peptides derived from microbiota species of the Firmicutes and the Bacteroidetes phyla, which together account for 90% of gut microbiota. Cross-reacting CD8+ T cell responses are very likely induced. Therefore, the anti-microbiota T cell memory may turn out to be an anti-cancer T cell memory, able to control the growth of a cancer developed during the lifetime if the expressed TAA is similar to the microbiota epitope. This may ultimately represent a relevant selective advantage for cancer patients and may lead to a novel preventive anti-cancer vaccine strategy.
Assuntos
Microbiota , Neoplasias , Antígenos de Neoplasias , Epitopos , Epitopos de Linfócito T , Humanos , Mimetismo Molecular , Receptores de Antígenos de Linfócitos T/genéticaRESUMO
BACKGROUND: People living with HIV/AIDS (PLWHA) show a reduced incidence for three cancer types, namely breast, prostate and colon cancers. In the present study, we assessed whether a molecular mimicry between HIV epitopes and tumor associated antigens and, consequently, a T cell cross-reactivity could provide an explanation for such an epidemiological evidence. METHODS: Homology between published TAAs and non-self HIV-derived epitopes have been assessed by BLAST homology. Structural analyses have been performed by bioinformatics tools. Immunological validation of CD8+ T cell cross-reactivity has been evaluated ex vivo by tetramer staining. FINDINGS: Sequence homologies between multiple TAAs and HIV epitopes have been found. High structural similarities between the paired TAAs and HIV epitopes as well as comparable patterns of contact with HLA and TCR α and ß chains have been observed. Furthermore, cross-reacting CD8+ T cells have been identified. INTERPRETATION: This is the first study showing a molecular mimicry between HIV antigens an TAAs identified in breast, prostate and colon cancers. Therefore, it is highly reasonable that memory CD8+ T cells elicited during the HIV infection may play a key role in controlling development and progression of such cancers in the PLWHA lifetime. This represents the first demonstration ever that a viral infection may induce a natural "preventive" anti-cancer memory T cells, with highly relevant implications beyond the HIV infection.
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Neoplasias do Colo , Infecções por HIV , Linfócitos T CD8-Positivos , Epitopos de Linfócito T , Antígenos HIV , Humanos , Masculino , Mimetismo Molecular , Receptores de Antígenos de Linfócitos TRESUMO
The host's immune system may be primed against antigens during the lifetime (e.g. microorganisms antigens-MoAs), and swiftly recalled upon growth of a tumor expressing antigens similar in sequence and structure. C57BL/6 mice were immunized in a preventive setting with tumor antigens (TuAs) or corresponding heteroclitic peptides specific for TC-1 and B16 cell lines. Immediately or 2-months after the end of the vaccination protocol, animals were implanted with cell lines. The specific anti-vaccine immune response as well as tumor growth were regularly evaluated for 2 months post-implantation. The preventive vaccination with TuA or their heteroclitic peptides (hPep) was able to delay (B16) or completely suppress (TC-1) tumor growth when cancer cells were implanted immediately after the end of the vaccination. More importantly, TC-1 tumor growth was significantly delayed, and suppressed in 6/8 animals, also when cells were implanted 2-months after the end of the vaccination. The vaccine-specific T cell response provided a strong immune correlate to the pattern of tumor growth. A preventive immunization with heteroclitic peptides resembling a TuA is able to strongly delay or even suppress tumor growth in a mouse model. More importantly, the same effect is observed also when tumor cells are implanted 2 months after the end of vaccination, which corresponds to 8 - 10 years in human life. The observed potent tumor control indicates that a memory T cell immunity elicited during the lifetime by a antigens similar to a TuA, i.e. viral antigens, may ultimately represent a great advantage for cancer patients and may lead to a novel preventive anti-cancer vaccine strategy.
Assuntos
Vacinas Anticâncer , Células T de Memória , Animais , Antígenos de Neoplasias , Humanos , Camundongos , Camundongos Endogâmicos C57BL , PeptídeosRESUMO
The antigenicity as well as the immunogenicity of tumor associated antigens (TAAs) may need to be potentiated in order to break the immunological tolerance. To this aim, heteroclitic peptides were designed introducing specific substitutions in the residue at position 4 (p4) binding to TCR. The effect of such modifications also on the affinity to the major histocompatibility class I (MHC-I) molecule was assessed. The Trp2 antigen, specific for the mouse melanoma B16F10 cells, as well as the HPV-E7 antigen, specific for the TC1 tumor cell lines, were used as models. Affinity of such heteroclitic peptides to HLA was predicted by bioinformatics tools and the most promising ones were validated by structural conformational and HLA binding analyses. Overall, we demonstrated that TAAs modified at the TCR-binding p4 residue are predicted to have higher affinity to MHC-I molecules. Experimental evaluation confirms the stronger binding, suggesting that this strategy may be very effective for designing new vaccines with improved antigenic efficacy.
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Antígeno HLA-A2 , Peptídeos , Animais , Antígenos de Neoplasias , Camundongos , Ligação Proteica , Receptores de Antígenos de Linfócitos TRESUMO
Background: In the present study we investigated whether peptides derived from the entire SARS-CoV-2 proteome share homology to TAAs (tumor-associated antigens) and cross-reactive CD8+ T cell can be elicited by the BNT162b2 preventive vaccine or the SARS-CoV-2 natural infection. Methods and results: Viral epitopes with high affinity (<100nM) to the HLA-A*02:01 allele were predicted. Shared and variant-specific epitopes were identified. Significant homologies in amino acidic sequence have been found between SARS-CoV-2 peptides and multiple TAAs, mainly associated with breast, liver, melanoma and colon cancers. The molecular mimicry of the viral epitopes and the TAAs was found in all viral proteins, mostly the Orf 1ab and the Spike, which is included in the BNT162b2 vaccine. Predicted structural similarities confirmed the sequence homology and comparable patterns of contact with both HLA and TCR α and ß chains were observed. CD8+ T cell clones cross-reactive with the paired peptides have been found by MHC class l-dextramer staining. Conclusions: Our results show for the first time that several SARS-COV-2 antigens are highly homologous to TAAs and cross-reactive T cells are identified in infected and BNT162b2 preventive vaccinated individuals. The implication would be that the SARS-Cov-2 pandemic could represent a natural preventive immunization for breast, liver, melanoma and colon cancers. In the coming years, real-world evidences will provide the final proof for such immunological experimental evidence. Moreover, such SARS-CoV-2 epitopes can be used to develop "multi-cancer" off-the-shelf preventive/therapeutic vaccine formulations, with higher antigenicity and immunogenicity than over-expressed tumor self-antigens, for the potential valuable benefit of thousands of cancer patients around the World.
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Linfócitos T CD8-Positivos , COVID-19 , Reações Cruzadas , Epitopos de Linfócito T , Mimetismo Molecular , SARS-CoV-2 , Humanos , SARS-CoV-2/imunologia , COVID-19/prevenção & controle , COVID-19/imunologia , Mimetismo Molecular/imunologia , Linfócitos T CD8-Positivos/imunologia , Reações Cruzadas/imunologia , Epitopos de Linfócito T/imunologia , Vacina BNT162/imunologia , Antígenos Virais/imunologia , Antígeno HLA-A2/imunologia , Neoplasias/imunologia , Neoplasias/prevenção & controle , Antígenos de Neoplasias/imunologia , Vacinas contra COVID-19/imunologiaRESUMO
BACKGROUND: We have recently shown extensive sequence and conformational homology between tumor-associated antigens (TAAs) and antigens derived from microorganisms (MoAs). The present study aimed to assess the breadth of T-cell recognition specific to MoAs and the corresponding TAAs in healthy subjects (HS) and patients with cancer (CP). METHOD: A library of > 100 peptide-MHC (pMHC) combinations was used to generate DNA-barcode labelled multimers. Homologous peptides were selected from the Cancer Antigenic Peptide Database, as well as Bacteroidetes/Firmicutes-derived peptides. They were incubated with CD8 + T cells from the peripheral blood of HLA-A*02:01 healthy individuals (n = 10) and cancer patients (n = 16). T cell recognition was identified using tetramer-staining analysis. Cytotoxicity assay was performed using as target cells TAP-deficient T2 cells loaded with MoA or the paired TuA. RESULTS: A total of 66 unique pMHC recognized by CD8+ T cells across all groups were identified. Of these, 21 epitopes from microbiota were identified as novel immunological targets. Reactivity against selected TAAs was observed for both HS and CP. pMHC tetramer staining confirmed CD8+ T cell populations cross-reacting with CTA SSX2 and paired microbiota epitopes. Moreover, PBMCs activated with the MoA where shown to release IFNγ as well as to exert cytotoxic activity against cells presenting the paired TuA. CONCLUSIONS: Several predicted microbiota-derived MoAs are recognized by T cells in HS and CP. Reactivity against TAAs was observed also in HS, primed by the homologous bacterial antigens. CD8+ T cells cross-reacting with MAGE-A1 and paired microbiota epitopes were identified in three subjects. Therefore, the microbiota can elicit an extensive repertoire of natural memory T cells to TAAs, possibly able to control tumor growth ("natural anti-cancer vaccination"). In addition, non-self MoAs can be included in preventive/therapeutic off-the-shelf cancer vaccines with more potent anti-tumor efficacy than those based on TAAs.
Assuntos
Epitopos de Linfócito T , Neoplasias , Humanos , Linfócitos T CD8-Positivos , Antígenos de Neoplasias , Peptídeos/químicaRESUMO
Cancer prevention is one of the aim with the highest priority in order to reduce the burden of cancer diagnosis and treatment on individuals as well as on healthcare systems. To this aim, vaccines represent the most efficient primary cancer prevention strategy. Indeed, anti-cancer immunological memory elicited by preventive vaccines might promptly expand and prevent tumor from progressing. Antigens derived from microorganisms (MoAs), represent the obvious target for developing highly effective preventive vaccines for virus-induced cancers. In this respect, the drastic reduction in cancer incidence following HBV and HPV preventive vaccines are the paradigmatic example of such evidence. More recently, experimental evidences suggest that MoAs may represent a "natural" anti-cancer preventive vaccination or can be exploited for developing vaccines to prevent cancers presenting highly homologous tumor-associated antigens (TAAs) (e.g. molecular mimicry). The present review describes the different preventive anti-cancer vaccines based on antigens derived from pathogens at the different stages of development.
Assuntos
Vacinas Anticâncer , Neoplasias , Humanos , Vacinas Anticâncer/uso terapêutico , Neoplasias/prevenção & controle , VacinaçãoRESUMO
Introduction: Currently, conventional treatments of hepatocellular carcinoma (HCC) are not selective enough for tumor tissue and lead to multidrug resistance and drug toxicity. Although sorafenib (SOR) is the standard first-line systemic therapy approved for the clinical treatment of HCC, its poor aqueous solubility and rapid clearance result in low absorption efficiency and severely limit its use for local treatment. Methods: Herein, we present the synthesis of biodegradable polymeric Poly (D, L-Lactide-co-glycolide) (PLGA) particles loaded with SOR (PS) by emulsion-solvent evaporation process. The particles are carefully characterized focusing on particle size, surface charge, morphology, drug loading content, encapsulation efficiency, in vitro stability, drug release behaviour and tested on HepG2 cells. Additionally, PLGA particles have been coupled on side emitting optical fibers (seOF) integrated in a microfluidic device for light-triggered local release. Results: PS have a size of 248 nm, tunable surface charge and a uniform and spherical shape without aggregation. PS shows encapsulation efficiency of 89.7% and the highest drug loading (8.9%) between the SOR-loaded PLGA formulations. Treating HepG2 cells with PS containing SOR at 7.5 µM their viability is dampened to 40%, 30% and 17% after 48, 129 and 168 hours of incubation, respectively. Conclusion: The high PS stability, their sustained release profile and the rapid cellular uptake corroborate the enhanced cytotoxicity effect on HepG2. With the prospect of developing biomedical tools to control the spatial and temporal release of drugs, we successfully demonstrated the potentiality of seOF for light-triggered local release of the carriers. Our prototypical system paves the way to new devices integrating microfluidics, optical fibers, and advanced carriers capable to deliver minimally invasive locoregional cancer treatments.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Nanopartículas , Humanos , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Sorafenibe , Ácido Láctico , Ácido Poliglicólico , Portadores de Fármacos , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Linhagem Celular Tumoral , Tamanho da PartículaRESUMO
Human endogenous retroviruses (HERVs) derive from ancestral exogenous retroviruses whose genetic material has been integrated in our germline DNA. Several lines of evidence indicate that cancer immunotherapy may benefit from HERV reactivation, which can be induced either by drugs or by cellular changes occurring in tumor cells. Indeed, several studies indicate that HERV proviral DNA can be transcribed either to double-stranded RNA (dsRNA) that is sensed as a "danger signal" by pattern recognition receptors (PRRs), leading to a viral mimicry state, or to mRNA that is translated into proteins that may contribute to the landscape of tumor-specific antigens (TSAs). Alternatively, HERV reactivation is associated with the expression of long noncoding RNAs (lncRNAs). In this review, we will highlight recent findings on HERV reactivation in cancer and its implications for cancer immunotherapy.
RESUMO
BACKGROUND: The host's immune system develops in equilibrium with both cellular self-antigens and non-self-antigens derived from microorganisms which enter the body during lifetime. In addition, during the years, a tumor may arise presenting to the immune system an additional pool of non-self-antigens, namely tumor antigens (tumor-associated antigens, TAAs; tumor-specific antigens, TSAs). METHODS: In the present study, we looked for homology between published TAAs and non-self-viral-derived epitopes. Bioinformatics analyses and ex vivo immunological validations have been performed. RESULTS: Surprisingly, several of such homologies have been found. Moreover, structural similarities between paired TAAs and viral peptides as well as comparable patterns of contact with HLA and T cell receptor (TCR) α and ß chains have been observed. Therefore, the two classes of non-self-antigens (viral antigens and tumor antigens) may converge, eliciting cross-reacting CD8+ T cell responses which possibly drive the fate of cancer development and progression. CONCLUSIONS: An established antiviral T cell memory may turn out to be an anticancer T cell memory, able to control the growth of a cancer developed during the lifetime if the expressed TAA is similar to the viral epitope. This may ultimately represent a relevant selective advantage for patients with cancer and may lead to a novel preventive anticancer vaccine strategy.
Assuntos
Antígenos de Neoplasias/imunologia , Antígenos Virais/imunologia , Epitopos , Memória Imunológica , Células T de Memória/imunologia , Sequência de Aminoácidos , Antígenos de Neoplasias/química , Antígenos Virais/química , Células Cultivadas , Reações Cruzadas , Bases de Dados de Proteínas , ELISPOT , Mapeamento de Epitopos , Interações Hospedeiro-Patógeno , Humanos , Interferon gama/metabolismo , Testes de Liberação de Interferon-gama , Células T de Memória/metabolismo , Células T de Memória/virologia , Modelos Imunológicos , Conformação Proteica , Homologia de Sequência de AminoácidosRESUMO
The response to anti-SARS-Cov-2 preventive vaccine shows high interpersonal variability at short and medium term. One of the explanations might be the individual HLA allelic variants. Indeed, B cell response is stimulated and sustained by CD4+ T helper cells activated by antigens presented by HLA-class II alleles on antigen-presenting cells (APCs). The impact of the number of antigens binding to HLA class-II alleles on the antibody response to the COVID vaccine has been assessed in a cohort of 56 healthcare workers who received the full schedule of the Pfizer-BioNTech BNT162b2 vaccine. Such vaccine is based on the entire spike protein of the SARS-CoV-2. Ab titers have been evaluated 2 weeks after the first dose as well as 2 weeks and 4 months after the boosting dose. HLA-DRB1 and DBQ1 for each of the vaccinees have been assessed, and strong binders have been predicted. The analysis showed no significant correlation between the short-medium-term Ab titers and the number of strong binders (SB) for each individual. These results indicate that levels of Ab response to the spike glycoprotein is not dependent on HLA class II allele, suggesting an equivalent efficacy at global level of the currently used vaccines. Furthermore, the pattern of persistence in Ab titer does not correlate with specific alleles or with the number of SBs.
Assuntos
Anticorpos Antivirais/sangue , Vacinas contra COVID-19/imunologia , Antígenos HLA-D/imunologia , SARS-CoV-2/imunologia , Anticorpos Antivirais/imunologia , Afinidade de Anticorpos/imunologia , Antígenos Virais/imunologia , Vacina BNT162 , COVID-19/prevenção & controle , Humanos , Glicoproteína da Espícula de Coronavírus/imunologiaRESUMO
Hepatocellular carcinoma (HCC) is the third leading cause of death from cancer globally. Indeed, only a few treatments are available, most of which are effective only for the early stages of the disease. Therefore, there is an urgent needing for potential markers for a specifically targeted therapy. Candidate proteins were selected from datasets of The Human Protein Atlas, in order to identify specific tumor-associated proteins overexpressed in HCC samples associated with poor prognosis. Potential epitopes were predicted from such proteins, and homology with peptides derived from viral proteins was assessed. A multiparametric validation was performed, including recognition by PBMCs from HCC-patients and healthy donors, showing a T-cell cross-reactivity with paired epitopes. These results provide novel HCC-specific tumor-associated antigens (TAAs) for immunotherapeutic anti-HCC strategies potentially able to expand pre-existing virus-specific CD8+ T cells with superior anticancer efficacy.
RESUMO
Tumor Associated Antigens (TAAs) may suffer from an immunological tolerance due to expression on normal cells. In order to potentiate their immunogenicity, heteroclitic peptides (htcPep) were designed according to prediction algorithms. In particular, specific modifications were introduced in peptide residues facing to TCR. Moreover, a MHC-optimized scaffold was designed for improved antigen presentation to TCR by H-2Db allele. The efficacy of such htcPep was assessed in C57BL/6 mice injected with syngeneic melanoma B16F10 or lung TC1 tumor cell lines, in combination with metronomic chemotherapy and immune checkpoint inhibitors. The immunogenicity of htcPep was significantly stronger than the corresponding wt peptide and the modification involving both MHC and TCR binding residues scored the strongest. In particular, the H-2Db-specific scaffold significantly potentiated the peptides' immunogenicity and control of tumor growth was comparable to wt peptide in a therapeutic setting. Overall, we demonstrated that modified TAAs show higher immunogenicity compared to wt peptide. In particular, the MHC-optimized scaffold can present different antigen sequences to TCR, retaining the conformational characteristics of the corresponding wt. Cross-reacting CD8+ T cells are elicited and efficiently kill tumor cells presenting the wild-type antigen. This novel approach can be of high clinical relevance in cancer vaccine development.
Assuntos
Apresentação de Antígeno/imunologia , Vacinas Anticâncer/imunologia , Antígenos de Histocompatibilidade/imunologia , Neoplasias Experimentais/imunologia , Peptídeos/imunologia , Vacinas de Subunidades Antigênicas/imunologia , Animais , Apresentação de Antígeno/efeitos dos fármacos , Antígenos de Neoplasias/imunologia , Antígenos de Neoplasias/metabolismo , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Vacinas Anticâncer/administração & dosagem , Linhagem Celular Tumoral , Terapia Combinada , Feminino , Humanos , Camundongos Endogâmicos C57BL , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/prevenção & controle , Peptídeos/metabolismo , Ligação Proteica , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Resultado do Tratamento , Carga Tumoral/efeitos dos fármacos , Carga Tumoral/imunologia , Vacinas de Subunidades Antigênicas/administração & dosagemRESUMO
Hepatocellular carcinoma (HCC) is the third leading cause of death from cancer globally. Indeed, there is a single drug approved as first-line systemic therapy in advanced unresectable HCC, providing a very limited survival benefit. In earlier stages, 5-year survival rates after surgical and loco-regional therapies are extremely variable depending on the stage of disease. Nevertheless, HCC is considered an immunogenic tumor arising in chronically inflamed livers. In such a scenario, immunotherapy strategies for HCC, in particular combinations including cancer vaccines, may represent a key therapeutic tool to improve clinical outcome in HCC patients. However, a lot of improvement is needed given the disappointing results obtained so far.
Assuntos
Carcinoma Hepatocelular/terapia , Imunoterapia/métodos , Neoplasias Hepáticas/terapia , Terapia Viral Oncolítica/métodos , Ablação por Radiofrequência , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/imunologia , Antineoplásicos Imunológicos/farmacologia , Antineoplásicos Imunológicos/uso terapêutico , Vacinas Anticâncer/uso terapêutico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/imunologia , Carcinoma Hepatocelular/mortalidade , Ensaios Clínicos como Assunto , Terapia Combinada/métodos , Metilases de Modificação do DNA/antagonistas & inibidores , Epigênese Genética/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/imunologia , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/imunologia , Neoplasias Hepáticas/mortalidade , Mutação , Vírus Oncolíticos , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/imunologia , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Sorafenibe/uso terapêutico , Taxa de Sobrevida , Resultado do Tratamento , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/imunologiaRESUMO
Disseminating Cancer Stem Cells (CSCs) initiate growth in specific niches of the host tissues, the cellular and molecular components of which sustain signaling pathways that support their survival, self-renewal dormancy and reactivation. In the metastatic niche, tumor cells may enter in a dormant state to survive and, consequently, the metastasis can remain latent for years. Despite the clinical importance of metastatic latency, little is known about what induces CSCs to enter a dormant state and what allows them to remain viable for years in this state. CSCs exhibit genetic, epigenetic and cellular adaptations that confer resistance to classical therapeutic approaches. The identification of potential CSC targets is complicated by the fact that CSCs may arise as a consequence of their relationship with the local microenvironment into the metastatic niches. Indeed, microenvironment modulates the capability of CSCs to evade the innate immune response and survive. Some new therapeutic options that include drugs targeting microenvironment components are achieving encouraging results in reducing the number of CSCs in tumors and/or overcoming their resistance in preclinical studies. This review will focus on specific CSC features with an emphasis on the role of tumor microenvironment in supporting metastatic dissemination of CSCs. In addition, it sheds light on potential microenvironment-targeted therapies aimed to counteract seeding and survival of CSCs in the metastatic niche.
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The interaction between the short 88Ser-Arg-Ser-Arg-Tyr92 sequence of the urokinase receptor (uPAR) and the formyl peptide receptor type 1 (FPR1) elicits cell migration. We generated the Ac-(D)-Tyr-(D)-Arg-Aib-(D)-Arg-NH2 (RI-3) peptide which inhibits the uPAR/FPR1 interaction, reducing migration of FPR1 expressing cells toward N-formyl-methionyl-leucyl-phenylalanine (fMLF) and Ser-Arg-Ser-Arg-Tyr (SRSRY) peptides. To understand the structural basis of the RI-3 inhibitory effects, the FPR1/fMLF, FPR1/SRSRY and FPR1/RI-3 complexes were modeled and analyzed, focusing on the binding pocket of FPR1 and the interaction between the amino acids that signal to the FPR1 C-terminal loop. We found that RI-3 shares the same binding site of fMLF and SRSRY on FPR1. However, while fMLF and SRSRY display the same agonist activation signature (i.e. the series of contacts that transmit the conformational transition throughout the complex), translating binding into signaling, RI-3 does not interact with the activation region of FPR1 and hence does not activate signaling. Indeed, fluorescein-conjugated RI-3 prevents either fMLF and SRSRY uptake on FPR1 without triggering FPR1 internalization and cell motility in the absence of any stimulus. Collectively, our data show that RI-3 is a true FPR1 antagonist and suggest a pharmacophore model useful for development of compounds that selectively inhibit the uPAR-triggered, FPR1-mediated cell migration.
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Peptídeos/metabolismo , Receptores de Formil Peptídeo/metabolismo , Receptores de Ativador de Plasminogênio Tipo Uroquinase/química , Sequência de Aminoácidos , Animais , Sítios de Ligação , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Células HEK293 , Humanos , Simulação de Dinâmica Molecular , Peptídeos/química , Peptídeos/farmacologia , Ligação Proteica , Mapas de Interação de Proteínas , Estrutura Terciária de Proteína , Ratos , Receptores de Formil Peptídeo/química , Receptores de Formil Peptídeo/genética , Relação Estrutura-AtividadeRESUMO
Drug resistance imposes severe limitations to the efficacy of targeted therapy in BRAF-mutated metastatic melanoma. Although this issue has been mitigated by the development of combination therapies with BRAF plus MEK inhibitors, drug resistance inevitably occurs with time and results in clinical recurrences and untreatable disease. Hence, there is strong need of developing new combination therapies and non-invasive diagnostics for the early identification of drug-resistant patients. We report here that the development of drug resistance to BRAFi is dominated by a dynamic deregulation of a large population of miRNAs, leading to the alteration of cell intrinsic proliferation and survival pathways, as well as of proinflammatory and proangiogenic cues, where a prominent role is played by the miR-199b-5p/VEGF axis. Significant alterations of miRNA expression levels are detectable in tumor biopsies and plasma from patients after disease recurrence. Targeting these alterations blunts the development of drug resistance.
Assuntos
Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Melanoma/tratamento farmacológico , Melanoma/genética , MicroRNAs/genética , Mutação , Inibidores de Proteínas Quinases/farmacologia , Vemurafenib/farmacologia , Proliferação de Células/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Melanoma/metabolismo , MicroRNAs/metabolismo , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas B-raf/metabolismoRESUMO
BACKGROUND: The biological behavior of epithelial ovarian cancer (EOC) is unique since EOC cells metastasize early to the peritoneum. Thereby, new anti-target agents designed to block trans-coelomic dissemination of EOC cells may be useful as anti-metastatic drugs. The Urokinase Plasminogen Activator Receptor (uPAR) is overexpressed in EOC tissues, and its truncated forms released in sera and/or ascitic fluid are associated with poor prognosis and unfavorable clinical outcome. We documented that uPAR triggers intra-abdominal dissemination of EOC cells through the interaction of its 84-95 sequence with the Formyl Peptide Receptor type 1 (FPR1), even as short linear peptide Ser-Arg-Ser-Arg-Tyr (SRSRY). While the pro-metastatic role of uPAR is well documented, little information regarding the expression and role of FPR1 in EOC is currently available. METHODS: Expression levels of uPAR and FPR1 in EOC cells and tissues were assessed by immunofluorescence, Western blot, or immunohystochemistry. Cell adhesion to extra-cellular matrix proteins and mesothelium as well as mesothelium invasion kinetics by EOC cells were monitored using the xCELLigence technology or assessed by measuring cell-associated fluorescence. Cell internalization of FPR1 was identified on multiple z-series by confocal microscopy. Data from in vitro assays were analysed by one-way ANOVA and post-hoc Dunnett t-test for multiple comparisons. Tissue microarray data were analyzed with the Pearson's Chi-square (χ2) test. RESULTS: Co-expression of uPAR and FPR1 by SKOV-3 and primary EOC cells confers a marked adhesion to vitronectin. The extent of cell adhesion decreases to basal level by pre-exposure to anti-uPAR84-95 Abs, or to the RI-3 peptide, blocking the uPAR84-95/FPR1 interaction. Furthermore, EOC cells exposed to RI-3 or desensitized with an excess of SRSRY, fail to adhere also to mesothelial cell monolayers, losing the ability to cross them. Finally, primary and metastatic EOC tissues express a high level of FPR1. CONCLUSIONS: Our findings identify for the first time FPR1 as a potential biomarker of aggressive EOC and suggests that inhibitors of the uPAR84-95/FPR1 crosstalk may be useful for the treatment of metastatic EOC.