<p>The RAS family is a group of small GTPases that can become constitutively activated by point mutations that are found in about 30% of all cancer patients. There are three well-characterized RAS family members: HRAS, NRAS, and KRAS, the latter of which is alternatively spliced at the C-terminus into KRAS4A and KRAS4B. The RAS proteins are all nearly identical at their N-termini and core effector binding domains, but have divergent C-terminal membrane-binding regions that impart different subcellular localization and subtle differences in signaling. Although the role of constitutively activated oncogenic RAS has been well established to play a role in cancer, recent work has suggested that wild-type RAS signaling may also be important in tumorigenesis. Wild-type RAS proteins have been shown to be activated in the presence of oncogenic KRAS. However, the consequences of this activation are context-dependent, as signaling through the wild-type RAS proteins has been shown to both suppress neoplastic growth and promote tumorigenesis under different circumstances.</p><p>I sought to investigate the role of the wild-type RAS proteins in two clinically –relevant models of cancer: pancreatic, the type of cancer most frequently associated with KRAS mutations, and lung cancer, the cancer in which KRAS mutations affect the highest number of patients. First, I tested whether a loss of wild type Hras altered tumorigenesis in a mouse model of pancreatic cancer driven by oncogenic Kras. Hras homozygous null mice (Hras-/- ) exhibited more precancerous lesions of the pancreas as well as more off-target skin papillomas compared to their wild type counterparts, indicating that Hras suppresses early Kras-driven pancreatic tumorigenesis. Loss of Hras also reduced the survival of mice engineered to develop aggressive pancreatic cancer by the additional disruption of one allele of the tumor suppressor p53 (Trp53R172H/+). However, this survival advantage was lost when both alleles of Trp53 were mutated, suggesting that wild-type HRas inhibits tumorigenesis in a p53-dependant manner. </p><p>Next, I investigated the role that wild-type Hras and Nras play in a chemical carcinogen-induced model of lung cancer. In mice treated with urethane, a carcinogen that induces Kras-mutation positive lung lesions, Hras-/ mice once again developed more tumors than wild-type mice. Interestingly, however, this effect was not observed in mice lacking wild-type Nras. Mice lacking both Hras and Nras alleles developed approximately the same number of tumors as Hras-/- mice, thus the additional loss of Nras does not appear to enhance the tumor-promoting effects of loss of Hras. In summary, signaling through wild-type Hras, but not Nras, suppresses tumorigenesis in a carcinogen-induced model of lung cancer.</p><p>The tumor-suppressive effects of wild-type Ras signaling were traced to the earliest stages of pancreatic tumorigenesis, suggesting that wild-type Ras signaling may suppress tumorigenesis as early as the time of initiation. These findings suggest that differences in expression of the wild-type Ras isoforms could potentially play a role in an individual’s predisposition for developing cancer upon oncogenic insult.</p> / Dissertation

Introdução: Imunidade inata é a primeira linha de defesa do hospedeiro contra microorganismos invasores, a qual é mediada por moléculas específicas que reconhecem patógenos, chamadas receptores toll-símile (TLRs). Os TLRs são também capazes de reconhecer ligantes endógenos, tais como conteúdos de células necróticas e proteínas de choque térmico (HSP), resultando na produção de citocinas e ativação do sistema imune adquirido. A função exata dos TLRs ainda é pouco entendida em transplante de órgãos. No entanto, tem sido sugerido que eles podem estar envolvidos na rejeição aguda ou crônica e atuar na resposta do enxerto a lesão por isquemia e reperfusão. Objetivo: Examinar as alterações na expressão gênica dos TLRs durante a fase inicial do transplante pulmonar em humanos e sua relação com citocinas potencialmente envolvidas na lesão por isquemia e reperfusão em transplante de órgãos. Métodos: Foram analisadas biópsias pulmonares de 14 pacientes submetidos a transplante pulmonar (LTx). Estas amostras foram coletadas no final do período de isquemia fria (TIF, n=14), no final do período de isquemia quente (TIQ, n=13),1 hora (n=12) e 2 horas (n=8) após a reperfusão do enxerto. RNA total foi isolado a partir de tecido pulmonar e os níveis de RNA mensageiro (mRNA) dos TLRs (1-10) bem como citocinas (IL-8, IL-6, IL-10, IFN-γ, IL-1β) e proteína de choque térmico 70 (HSP70) foram medidos por reação em cadeia pela polimerase em tempo real. Resultados: Foi detectada a expressão de mRNA de todos TLRs em tecido pulmonar. Nas amostras no TIF, os níveis de mRNA dos TLRs apresentaram-se com diferentes expressões gênicas. Os níveis de expressão dos TLRs, com exceção para o TLR3, estavam altamente correlacionados entre si no TIF e com os níveis de mRNA de IFN-γ, IL-10 e IL-1β e menos significativamente com os níveis de IL-6 e IL-8. Houve diminuição dos níveis de mRNA na grande maioria dos TLRs após reperfusão, o que foi diferente para a maioria das citocinas e HSP70, que apresentaram tendência a aumentar após transplante. A expressão gênica de TLR4 apresentou-se correlacionada com os níveis de IL-8 e IL-1β antes e após transplante (P<0.05). Pulmões de doadores que foram intubados por períodos acima de 72 horas (n=5) apresentaram níveis mais elevados de TLR2 e TLR10 (P<0.05). Conclusão: Pela primeira vez, foi demonstrado que a expressão dos TLRs altera-se durante o período de isquemia e reperfusão em transplante pulmonar em humanos. O tempo de intubação dos doadores pulmonares pode influenciar a expressão de receptores Toll-símile específicos. A correlação entre TLR4 e IL-8/IL-1β sugere que os TLRs pulmonares podem ter alguma função na resposta precoce do enxerto. / Introduction: Innate immunity is the first line of host defense against invading microorganisms, which is mediated by specific pathogen recognition molecules called Toll-like receptors (TLRs). TLRs can also recognize endogenous ligands, such as contents of necrotic cells and heat shock proteins (HSP), resulting in cytokine production and activation of adaptive immune system. The exact role of the Toll-like receptors and their signalling pathways is still poorly understood in organ transplantation. However, it is suggested that they may be involved in either chronic or acute organ rejection and may play a role in graft response to ischemia reperfusion injury. Objective: To examine the changes in gen expression of TLRs during the early phase of human lung transplantation and their relationship with cytokines potentially involved in ischemia reperfusion injury in organ transplantation. Methods: We analyzed lung biopsies from 14 patients submitted to lung transplantation (LTx). Biopsies were collected at the end of the cold ischemic time (CIT, n=14), end of warm ischemic time (WIT, n=13), and after 1h (n=12) and 2h (n=8) of reperfusion. Total RNA was isolated from lung tissues, and messenger RNA (mRNA) levels of TLRs (TLR 1-10) as well as cytokines (IL-8, IL-6, IL-10, IFN-γ and IL-1β) and heat shock protein 70 (HSP70) were measured by quantitative real-time polymerase chain reaction. Results: We observed mRNA expression of all TLRs in lung tissue. In the CIT samples, TLR mRNAs levels were differentially expressed in donor samples. In the CIT samples, the expression levels of TLRs, except for TLR3, were highly correlated with each other and with mRNA levels of IFN-γ, IL-10 and IL-1β, and less significantly correlated with IL-6 and IL-8. After reperfusion, expression of almost all TLR mRNAs decreased to lower levels what was different for most of the cytokines and HSP70, which trended to increase after LTx. TLR4 gen expression was closely correlated with IL-8 and IL-1β levels prior to and after LTX (P<0.01). Lungs from donors who were intubated longer than 72 h (n=5) expressed higher levels of TLR2 and TLR10 (P<0.05). Conclusion: For the first time, we showed that the expression of TLRs is altered during ischemia-reperfusion period of human lung transplantation. The donor length of intubation may influence the expression of specific TLRs. Correlation between TLR4 and IL-8/IL-1β suggests that pulmonary TLRs may play a role in early graft response.

Aim: The aim of this thesis was to measure a large spectrum of biomarkers in serum or plasma of patients with operable stage of NSCLC and to evaluate and compare the clinical utility of these biomarkers in the three most important clinical applications for NSCLC: diagnosis, prognosis and postsurgery follow up care. Patients and methods: Total of 22 biomarkers with the most promising profiles were monitored: 8 standard tumor markers (cytokeratines Cyfra 21-1, TPA, TPS, and MonoTotal, CEA, SCC, TK, Chromogranin A) and 14 potential useful biomarkers including pro-inflammatory cytokines IL-6, IL-8, MCP-1, pro-angiogenic cytokine VEGF, matrix metaloproteinases MMP-1, MMP-2, MMP-7, MMP-9 and their inhibitors TIMP-1 and TIMP-2, adhesion molecules ICAM-1, VCAM-1, growth factor IGF-1, and PAI-1 stimulating tumor growth and angiogenesis. With a view of evaluating the clinical relevance of these markers for NSCLC we measured serum or plasma levels of these 22 markers in group of 93 patients with NSCLC undergoing radical surgery and in group of 20 patients with benign lung disease. For biomarker measurement were used conventional immunoanalytic routine methods (IRMA, REA, CLIA, MEIA, TRACE, ELISA) and multiplex immunoanalytic method. Results: Cyfra 21-1, MonoTotal, TPA, TPS, CEA, SCC, Chromogranin A, TIMP-1, MMP-1,...

BACKGROUND: There is a need to identify the populations at high risk of nonadherence to outpatient lung cancer appointments in order to reduce the delay from diagnosis to treatment. The patient navigation system, which helps patients with barriers navigate the health care system, was examined to see if the correct high-risk groups were being addressed. METHODS: A case-control study with 195 subjects from the lung cancer clinics at Boston Medical Center (BMC) was conducted examining three nonadherence case groups: no-shows (n=40), cancelations (n=64) and combined (n=20). Nonadherence was defined as any patient who was a no-show for at least one appointment or who canceled more than one appointment over the three month study period. The combined group incorporated both of these factors. The patients were stratified by 10 patient characteristics, including patient navigation. Odds ratios (ORs) and 95% confidence intervals (CIs) were used for the analysis. A second analysis was done on patients in the patient navigation program (n=33) to determine if the high risk groups identified were being addressed. This was done using ORs and 95% CIs. RESULTS: This study has shown that there are certain patient groups in the lung cancer clinics at BMC that are at higher risk of being nonadherent to lung cancer outpatient appointments. Among those are Hispanic/Latino patients, Spanish and Haitian Creole speaking patients, small cell lung cancer (SCLC) patients, and those patients who have Medicaid, and with late stage lung cancer patients at significantly higher risk (no-shows: OR-5.26 (1.85, 14.95), cancelations: OR-2.49 (1.12, 5.54), combined: OR-12.49 (1.48, 105.46)). Patients in the patient navigation system were also found to be at significantly higher risk of nonadherence (no-shows: OR-3.85 (1.72, 8.65), cancelations: OR-4.13 (1.89, 9.00), combined: OR-5.15 (1.93, 13.72)) than those not in the program. Some patients were also found to be at significantly decreased odds of nonadherence, including those who were: 1000-1999 days post diagnosis (no-shows: OR-0.14 (0.03, 0.59), cancelations: OR-0.20 (0.06, 0.65), combined: OR-0.07 (0.01, 0.64)); 2000-2999 days post diagnosis (no-shows: OR-0.09 (0.01, 0.80), cancelations: OR-0.06 (0.01, 0.50)); aged 71-75 (cancelations: OR-0.25 (0.08, 0.79)). The subset analysis with the patient navigation data yielded no statistically significant results. CONCLUSIONS: The study identified high-risk populations within the total lung cancer population at BMC that should be addressed by the patient navigation program. This study demonstrated that while the program does have its flaws, it is decreasing the odds of nonadherence of many of the high-risk populations.

Lung cancer is the most common cause of cancer-related mortality worldwide with current treatments providing limited therapeutic benefit in most cases. TP53 (Trp53, p53) mutations occur in approximately 50% of lung adenocarcinoma cases and are associated with poor prognosis and so novel therapies that target these p53 mutant lung tumours are urgently needed. Despite the high frequency of p53 mutations in lung tumours, the impact these mutations have on response to therapy remains unclear in this cancer type. The aim of my project is to characterise the gain-of-function and dominant-negative effects of p53 mutations in lung tumours and to identify ways of therapeutically targeting these p53 mutant tumours based on dependencies and susceptibilities that our analysis uncovers. To characterise the gain-of-function and dominant-negative effects of p53 mutations I compared p53 mutant murine lung tumour cells that endogenously express either a contact (R270H, equivalent to R273H in humans) or conformational (R172H, equivalent to R175H in humans) p53 mutant protein and p53 null lung tumour cell lines; both in the presence and absence of wild-type p53. Interestingly, transcriptional and functional analysis uncovered metabolic gain-of-functions that are specific to the type of p53 mutation. Upregulation of mevalonate pathway expression was observed only in R270H lung tumours and consequently R172H and R270H lung tumours displayed distinct sensitivities to simvastatin, a mevalonate pathway inhibitor widely used in the clinic. Furthermore, the transcriptional signature underlying this sensitivity to simvastatin was also present in human lung tumours with contact p53 mutations, indicating that these findings may be clinically relevant. On the other hand, our analysis of the potential dominant-negative effects of the p53 mutants on wild-type p53 demonstrated that wild-type p53 was able to induce typical p53 target genes to a similar level in p53 null and mutant cells. Furthermore, wild-type p53 restoration resulted in comparable tumour suppressive responses in p53 mutant and null tumours and thus, p53-restoration therapy will likely be of benefit to patients with p53 mutations in lung cancer. Hence, I have demonstrated that lung tumours harbouring contact and conformational p53 mutations display common and distinct therapeutic susceptibilities.

Background: Studies evaluating the possible health-promoting effects of sound nutrition in heart and lung transplant recipients are currently lacking. Despite advances in drug treatment and patient monitoring, lifestyle-associated complications such as obesity, diabetes and cardiovascular disease occur frequently. Following transplantation, a low-fat eating pattern is currently viewed as best standard care. However, a Mediterranean diet based on a varied range of fresh unprocessed foods and supplemented with extra virgin olive oil has demonstrated clinical benefit in various non-transplant populations. The aim of this study was to evaluate the feasibility and acceptability of a Mediterranean vs a low-fat diet intervention in heart and lung transplant recipients, and to assess clinical and biochemical outcomes. Methods: This was a randomised controlled feasibility trial to evaluate a Mediterranean diet supplemented with extra-virgin olive oil, vs a modified low-fat diet in heart and lung transplant recipients at a single centre. In total, 41 clinically stable male and female (median age 55 years) transplant recipients were randomly assigned (1:1) in two separate 12-month waves (n=24 and n=17) to one of these diet interventions. A range of validated food frequency and adherence questionnaires captured changes in participants' reported eating habits to 6 weeks post-study. Clinical and biochemical analysis was conducted at baseline, 25 and 52 weeks. Telephone and outpatient contact provided a support mechanism to reinforce dietary behavioural change. Caloric intake and physical exercise awareness were discussed, but not promoted. Results: Thirty nine participants completed the trial (95%). Adherence to both interventions improved significantly at week 25, and was maintained at 52 and 58 weeks. Compared with baseline, waist circumference decreased in both groups at week 25 (p=0.024). A decrease in blood pressure and heart rate occurred at 52 weeks in the low-fat group only. At 52 weeks, higher adherence resulted in significant improvements in fasting glucose in the Mediterranean (< 4.8%) and low-fat (< 5%) groups. This respective pattern was also observed with total cholesterol (≤ 9% and ≤ 7%), triglycerides (≤ 9% and ≤ 20%) and IGF-1 (≤ 9% and ≤ 15%). A significant decrease in the LDL/HDL ratio (≤ 12%) occurred in the Mediterranean group only. Moreover, clinically relevant lipid and glucose regulation changes were observed in each intervention. Conclusions: The implementation of a prospective 12-month Mediterranean or low-fat diet is feasible and acceptable in a heart and lung transplant outpatient setting. Both interventions were positively associated with improvements in lipid and blood glucose regulation and circulating IGF-1. As part of a multidisciplinary framework, these findings offer an additional therapeutic strategy to optimise outpatient care.

Innate immune cells, such as macrophages, are trained by the unique microenvironment of the tissue they occupy. This tissue influence can include the extracellular matrix, the presence of inflammatory stimuli or signals and, in some tissues, the microbiota. Most studies, however, have examined such tissue specific training in health whereas little is known about the possibility of immune re-training in the lung following acute inflammation. The lung extracellular matrix is important for mechanical stability and structural support, as well as influencing inflammation via altering cell adhesion, migration, survival, proliferation and differentiation. Matrix alterations are a feature of a number of significant chronic respiratory diseases that carry high clinical unmet need. These include idiopathic pulmonary fibrosis, cystic fibrosis and chronic obstructive pulmonary disease (COPD). On the other hand, the impact on matrix after acute inflammation and whether it is returned to its pre-infection state is relatively unexplored. In murine models, macroscopic examination of the lung following acute inflammation implies a return to a reasonable homeostatic state. However, using more sensitive techniques, we now show that this is not the case. In this thesis we test the premise that a more thorough interrogation of lung extracellular matrix by mass spectrometry will reveal long term alterations that are not visible by histology. After influenza virus infection, we demonstrate that heightened extracellular matrix persists in the lung tissue, often forming structures that were not present in health. Furthermore, basement membrane components, for example collagen IV and laminin, are reduced. In vitro investigations show that individual extracellular matrix components affect lung macrophage activity. For example, hyaluronan and fibronectin alter macrophage expression of microRNA species known to influence toll-like receptor responsiveness and fibrosis. We also describe an alteration in microRNA species in response to influenza virus infection as well as a non-infectious model of pulmonary inflammation using carbon nanotubes. Collectively, this implies that altered matrix composition impacts on the inflammatory tone of the lung innate immune system. It is therefore feasible that such changes following severe lung inflammation could be overcome by targeting abnormal matrix production or degradation.

We describe an online clinical decision support (CDS) system, Lung Cancer Assistant (LCA), which we have developed to aid the clinicians in arriving at informed treatment decisions for lung cancer patients at multidisciplinary team (MDT) meetings. LCA integrates rule-based and probabilistic decision support within a single platform. To our knowledge, this is the first time this has been achieved in the context of CDS in cancer care. Rule-based decision support is achieved by an original ontological guideline rule inference framework that operates on a domain-specific module of Systematized Nomenclature of Medicine-Clinical Terms (SNOMED-CT), containing clinical concepts and guideline rule knowledge elicited from the major national and international guideline publishers. It adopts a conventional argumentation-based decision model, whereby the decision options are listed along with arguments derived by matching the patient records to the guideline rule base. As an additional feature of this framework, when a new patient is entered, LCA displays the most similar patients to the one being viewed. Probabilistic inference is provided by a Bayesian Network (BN) whose structure and parameters have been learned based on the English Lung Cancer Database (LUCADA). This allows LCA to predict the probability of patient survival and lay out how the selection of different treatment plans would affect it. Based on a retrospective patient subset from LUCADA, we present empirical results on the treatment recommendations provided by both functionalities of LCA and discuss their strengths and weaknesses. Finally, we present preliminary work, which may allow utilising the BN to calculate survival odd ratios that could be translated into quantitative degrees of support for the guideline rule-based arguments. An online version of LCA is accessible on http://lca.eng.ox.ac.uk.

Objetivos: Desenvolver e caracterizar nanocápsulas poliméricas contendo erlotinib, bem como avaliar sua atividade antitumoral in vitro em células de adenocarcinoma de pulmão humano. Metodologia: As nanocápsulas contendo erlotinib (0,5 mg.mL-1) foram obtidas pelo método de nanoprecipitação utilizando poli(ε-caprolactona) e óleo de copaíba como parede polimérica e núcleo oleoso, respectivamente. Os parâmetros físico-químicos avaliados foram: diâmetro médio e distribuição de tamanho, índice de polidispersão, potencial zeta, concentração de partículas e pH. Para determinação do teor e eficiência de encapsulação do erlotinib, utilizou-se metodologia validada por CLAE-UV. O estudo de liberação in vitro, utilizando sacos de diálise, foi realizado para obter o perfil de liberação do fármaco a partir das nanocápsulas. As nanocápsulas contendo erlotinib foram avaliadas quanto ao seu potencial de inibir o crescimento, induzir a apoptose, interferir com o ciclo celular e sobrevivência clonogênica de células de adenocarcinoma de pulmão, linhagem A549. Resultados: As nanocápsulas apresentaram diâmetro médio de 171 ± 2 (PDI < 0, 10), potencial zeta de −8,17 ± 2.26 mV, número de partículas por mL de 6,97 ± 0,22 × 1013 e pH de 6,24 ± 0,02. O teor e a eficiência de encapsulação foram próximos de 100%. Com exceção do pH, todos parâmetros mantiveram-se iguais após 30 dias de armazenamento em temperatura ambiente. Observou-se uma liberação controlada do fármaco devido à nanoencapsulação. Os ensaios de citotoxicidade demonstraram que as nanocápsulas contendo erlotinib apresentaram maior atividade antitumoral quando comparado com o fármaco livre. Também foi demonstrado indução de apoptose, pela análise de ciclo celular e marcação por Anexina-V conjugada ao 7-AAD. No ensaio clonogênico, as nanocápsulas contendo erlotinib reduziram 100% o número de colônias formadas. Conclusões: Foram obtidas nanocápsulas com propriedades nanotécnologicas adequadas e capazes de controlar a liberação do erlotinib. Os estudos in vitro na linhagem celular A549 demonstraram aumento no efeito antitumoral e foi demonstrado que o encapsulamento do fármaco é imprescindível para essa melhor atividade. / Purpose: To develop and characterise erlotinib-loaded polymeric nanocapsules and to evaluate its in vitro antitumor activity in human lung adenocarcinoma cells. Methodology: The erlotinib-loaded nanocapsules (0.5 mg.mL-1) were obtained by nanoprecipitation method using poly (ε-caprolactone) and copaiba oil as the polymeric wall and oily core, respectively. The physicochemical parameters evaluated were: mean diameter and size distribution, polydispersity index, zeta potential, particle concentration and pH. An HPLC-UV validated method was used to determine the drug content and encapsulation efficiency. The in vitro release study using dialysis bags was performed to obtain the drug release profile from nanocapsules. The erlotinib-loaded nanocapsules were evaluated regarding their potential to inhibit the growth, induce apoptosis, interfere with the cell cycle and clonogenic survival of lung adenocarcinoma cell (A549). Results: The nanocapsule formulation presented z-average diameter of 171 ± 2 (PDI <0.10), zeta potential value of -8.17 ± 2.26 mV, number of particles per mL of 6.97 ± 0.22 × 1013, and pH value of 6.24 ± 0.02. The drug content and the encapsulation efficiency were nearly 100%. Except for the pH value, all these parameters remained the same after 30 days of storage. A controlled release of the drug was observed due to nanoencapsulation. The cytotoxicity assays demonstrated that the erlotinib-loaded nanocapsules showed higher antitumor activity compared to free drug. Induction of apoptosis was demonstrated by cell cycle analysis and Annexin-V/7AAD staining. In the clonogenic assay, erlotinib-loaded nanocapsules reduced 100% the number of colonies formed. Conclusions: Nanocapsules with appropriate nanotechnological properties and capable of controlling the erlotinib release were obtained. The in vitro studies in the A549 cell line showed an increase in antitumor effect and was demonstrated that the drug encapsulation is essential for this better activity.

Introdução: Imunidade inata é a primeira linha de defesa do hospedeiro contra microorganismos invasores, a qual é mediada por moléculas específicas que reconhecem patógenos, chamadas receptores toll-símile (TLRs). Os TLRs são também capazes de reconhecer ligantes endógenos, tais como conteúdos de células necróticas e proteínas de choque térmico (HSP), resultando na produção de citocinas e ativação do sistema imune adquirido. A função exata dos TLRs ainda é pouco entendida em transplante de órgãos. No entanto, tem sido sugerido que eles podem estar envolvidos na rejeição aguda ou crônica e atuar na resposta do enxerto a lesão por isquemia e reperfusão. Objetivo: Examinar as alterações na expressão gênica dos TLRs durante a fase inicial do transplante pulmonar em humanos e sua relação com citocinas potencialmente envolvidas na lesão por isquemia e reperfusão em transplante de órgãos. Métodos: Foram analisadas biópsias pulmonares de 14 pacientes submetidos a transplante pulmonar (LTx). Estas amostras foram coletadas no final do período de isquemia fria (TIF, n=14), no final do período de isquemia quente (TIQ, n=13),1 hora (n=12) e 2 horas (n=8) após a reperfusão do enxerto. RNA total foi isolado a partir de tecido pulmonar e os níveis de RNA mensageiro (mRNA) dos TLRs (1-10) bem como citocinas (IL-8, IL-6, IL-10, IFN-γ, IL-1β) e proteína de choque térmico 70 (HSP70) foram medidos por reação em cadeia pela polimerase em tempo real. Resultados: Foi detectada a expressão de mRNA de todos TLRs em tecido pulmonar. Nas amostras no TIF, os níveis de mRNA dos TLRs apresentaram-se com diferentes expressões gênicas. Os níveis de expressão dos TLRs, com exceção para o TLR3, estavam altamente correlacionados entre si no TIF e com os níveis de mRNA de IFN-γ, IL-10 e IL-1β e menos significativamente com os níveis de IL-6 e IL-8. Houve diminuição dos níveis de mRNA na grande maioria dos TLRs após reperfusão, o que foi diferente para a maioria das citocinas e HSP70, que apresentaram tendência a aumentar após transplante. A expressão gênica de TLR4 apresentou-se correlacionada com os níveis de IL-8 e IL-1β antes e após transplante (P<0.05). Pulmões de doadores que foram intubados por períodos acima de 72 horas (n=5) apresentaram níveis mais elevados de TLR2 e TLR10 (P<0.05). Conclusão: Pela primeira vez, foi demonstrado que a expressão dos TLRs altera-se durante o período de isquemia e reperfusão em transplante pulmonar em humanos. O tempo de intubação dos doadores pulmonares pode influenciar a expressão de receptores Toll-símile específicos. A correlação entre TLR4 e IL-8/IL-1β sugere que os TLRs pulmonares podem ter alguma função na resposta precoce do enxerto. / Introduction: Innate immunity is the first line of host defense against invading microorganisms, which is mediated by specific pathogen recognition molecules called Toll-like receptors (TLRs). TLRs can also recognize endogenous ligands, such as contents of necrotic cells and heat shock proteins (HSP), resulting in cytokine production and activation of adaptive immune system. The exact role of the Toll-like receptors and their signalling pathways is still poorly understood in organ transplantation. However, it is suggested that they may be involved in either chronic or acute organ rejection and may play a role in graft response to ischemia reperfusion injury. Objective: To examine the changes in gen expression of TLRs during the early phase of human lung transplantation and their relationship with cytokines potentially involved in ischemia reperfusion injury in organ transplantation. Methods: We analyzed lung biopsies from 14 patients submitted to lung transplantation (LTx). Biopsies were collected at the end of the cold ischemic time (CIT, n=14), end of warm ischemic time (WIT, n=13), and after 1h (n=12) and 2h (n=8) of reperfusion. Total RNA was isolated from lung tissues, and messenger RNA (mRNA) levels of TLRs (TLR 1-10) as well as cytokines (IL-8, IL-6, IL-10, IFN-γ and IL-1β) and heat shock protein 70 (HSP70) were measured by quantitative real-time polymerase chain reaction. Results: We observed mRNA expression of all TLRs in lung tissue. In the CIT samples, TLR mRNAs levels were differentially expressed in donor samples. In the CIT samples, the expression levels of TLRs, except for TLR3, were highly correlated with each other and with mRNA levels of IFN-γ, IL-10 and IL-1β, and less significantly correlated with IL-6 and IL-8. After reperfusion, expression of almost all TLR mRNAs decreased to lower levels what was different for most of the cytokines and HSP70, which trended to increase after LTx. TLR4 gen expression was closely correlated with IL-8 and IL-1β levels prior to and after LTX (P<0.01). Lungs from donors who were intubated longer than 72 h (n=5) expressed higher levels of TLR2 and TLR10 (P<0.05). Conclusion: For the first time, we showed that the expression of TLRs is altered during ischemia-reperfusion period of human lung transplantation. The donor length of intubation may influence the expression of specific TLRs. Correlation between TLR4 and IL-8/IL-1β suggests that pulmonary TLRs may play a role in early graft response.