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Background: Liver fibrosis is a leading cause of morbimortality in people with HIV/hepatitis C virus (HCV). Natural killer (NK) cells are linked with amelioration of liver fibrosis; however, NK cells from individuals coinfected with HIV/HCV with cirrhosis display impaired functionality and high PD-1 expression. Here, we aimed to study PD-1, TIGIT, and Tim3 as potential exhaustion markers in NK cells from persons coinfected with HIV/HCV with mild and advanced liver fibrosis. We also evaluated the role of PD-1 expression on NK cells after HCV clearance by direct-acting antivirals (DAAs). Methods: Peripheral blood mononuclear cells were isolated from individuals coinfected with HIV/HCV (N = 54; METAVIR F0/F1, n = 27; F4, evaluated by transient elastography, n = 27). In 26 participants, samples were collected before, at the end of, and 12 months after successful DAA treatment. The frequency, immunophenotype (PD-1, TIGIT, and Tim3 expression), and degranulation capacity (CD107a assay) of NK cells were determined by flow cytometry. Results: Unlike PD-1, Tim3 and TIGIT were comparably expressed between persons with mild and advanced fibrosis. Degranulation capacity was diminished in NK/TIGIT+ cells in both fibrosis stages, while NK/PD-1+ cells showed a lower CD107a expression in cirrhotic cases. Twelve months after DAA treatment, those with advanced fibrosis showed an improved NK cell frequency and reduced NK/PD-1+ cell frequency but no changes in CD107a expression. In individuals with mild fibrosis, neither PD-1 nor NK cell frequency was modified, although the percentage of NK/CD107a+ cells was improved at 12 months posttreatment. Conclusions: Although DAA improved exhaustion and frequency of NK cells in cirrhotic cases, functionality was reverted only in mild liver fibrosis, remarking the importance of an early DAA treatment.
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BACKGROUND: A sterilizing cure of HIV-1 infection has been reported in 2 persons living with HIV-1 who underwent allogeneic hematopoietic stem cell transplantations from donors who were homozygous for the CCR5Δ32 gene polymorphism. However, this has been considered elusive during natural infection. OBJECTIVE: To evaluate persistent HIV-1 reservoir cells in an elite controller with undetectable HIV-1 viremia for more than 8 years in the absence of antiretroviral therapy. DESIGN: Detailed investigation of virologic and immunologic characteristics. SETTING: Tertiary care centers in Buenos Aires, Argentina, and Boston, Massachusetts. PATIENT: A patient with HIV-1 infection and durable drug-free suppression of HIV-1 replication. MEASUREMENTS: Analysis of genome-intact and replication-competent HIV-1 using near-full-length individual proviral sequencing and viral outgrowth assays, respectively; analysis of HIV-1 plasma RNA by ultrasensitive HIV-1 viral load testing. RESULTS: No genome-intact HIV-1 proviruses were detected in analysis of a total of 1.188 billion peripheral blood mononuclear cells and 503 million mononuclear cells from placental tissues. Seven defective proviruses, some of them derived from clonally expanded cells, were detected. A viral outgrowth assay failed to retrieve replication-competent HIV-1 from 150 million resting CD4+ T cells. No HIV-1 RNA was detected in 4.5 mL of plasma. LIMITATIONS: Absence of evidence for intact HIV-1 proviruses in large numbers of cells is not evidence of absence of intact HIV-1 proviruses. A sterilizing cure of HIV-1 can never be empirically proved. CONCLUSION: Genome-intact and replication-competent HIV-1 were not detected in an elite controller despite analysis of massive numbers of cells from blood and tissues, suggesting that this patient may have naturally achieved a sterilizing cure of HIV-1 infection. These observations raise the possibility that a sterilizing cure may be an extremely rare but possible outcome of HIV-1 infection. PRIMARY FUNDING SOURCE: National Institutes of Health and Bill & Melinda Gates Foundation.
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Infecções por HIV/genética , Infecções por HIV/imunologia , HIV-1/genética , Receptores CCR5/genética , Adulto , Argentina , Linfócitos T CD4-Positivos/imunologia , Feminino , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala , Interações Hospedeiro-Patógeno , Humanos , Massachusetts , Gravidez , Resultado da Gravidez , Provírus/genética , Provírus/imunologia , Carga Viral , Viremia/virologia , Replicação Viral/imunologiaRESUMO
Biobanks are instrumental for accelerating research. Early in SARS-CoV-2 pandemic, the Argentinean Biobank of Infectious Diseases (BBEI) initiated the COVID19 collection and started its characterization. Blood samples from subjects with confirmed SARS-CoV-2 infection either admitted to health institutions or outpatients, were enrolled. Highly exposed seronegative individuals, were also enrolled. Longitudinal samples were obtained in a subset of donors, including persons who donated plasma for therapeutic purposes (plasma donors). SARS-CoV-2-specific IgM and IgG levels, IgG titers and IgG viral neutralization capacity were determined. Out of 825 donors, 57.1% were females and median age was 41 years (IQR 32-53 years). Donors were segregated as acute or convalescent donors, and mild versus moderate/severe disease donors. Seventy-eight percent showed seroconversion to SARS-CoV-2 specific antibodies. Specific IgM and IgG showed comparable positivity rates in acute donors. IgM detectability rate declined in convalescent donors while IgG detectability remained elevated in early (74,8%) and late (83%) convalescent donors. Among donors with follow-up samples, IgG levels seemed to decline more rapidly in plasma donors. IgG levels were higher with age, disease severity, number of symptoms, and more durable in moderate/severe disease donors. Levels and titers of anti-spike/RBD IgG strongly correlated with neutralization activity against WT virus. The BBEI-COVID19 collection serves a dual role in this SARS-CoV-2 global crisis. First, it feeds researchers and developers transferring samples and data to fuel research projects. Second, it generates highly needed local data to understand and frame the regional dynamics of the infection.
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La pandemia de COVID-19 ha puesto en jaque a los sistemas de salud en el mundo; la vinculación entre la investigación biomédica y la práctica asistencial ha probado ser un requisito fundamental para dar respuesta a la misma de manera eficiente y rápida. En este sentido, los biobancos se constituyen como un componente clave ya que favorecen el almacenamiento de grandes volúmenes de muestras biológicas gestionadas en base a criterios que garanticen su óptima calidad, armonización y seguridad, respetando requisitos éticos y legales que aseguran los derechos de los ciudadanos. La cesión de estas muestras a distintos grupos de investigación promueve el desarrollo de nuevas herramientas diagnósticas y terapéuticas y vacunas. Frente a la llegada del SARS-CoV-2 a la Argentina, el Biobanco de Enfermedades Infecciosas estableció rápidamente la colección COVID-19 constituida por muestras de plasma, suero y células mononucleares de sangre periférica de personas cursando la enfermedad o recuperadas. En solo seis meses se enrolaron 825 donantes, lo que significa alrededor de 14.000 viales de material biológico almacenados y a disposición de los investigadores que lo soliciten. A tal efecto, se realizaron seis actos de cesión a diversos grupos pertenecientes a instituciones de investigación, mientras que tres se encuentran en evaluación. Las muestras cedidas han permitido, por ejemplo, el desarrollo de kits serológicos de producción nacional; lo que pone de manifiesto que el rápido establecimiento de esta colección, bajo un sistema de gestión eficiente, constituye una herramienta muy valiosa en la respuesta a esta nueva enfermedad
The COVID-19 pandemic has driven an unprecedented health crisis. Cooperation between biomedical research and healthcare practice has been shown to be a fundamental requirement to provide an efficient and timely response. In this regard, biobanks are key components since they allow the storage of large volumes of biological samples with guaranteed optimum quality, harmonization and safety, ensuring ethical and legal requirements which protect citizen rights. The transfer of these samples to different research groups fosters the development of new diagnostic and therapeutic tools as well as vaccines. Upon SARS-CoV-2 arrival to Argentina, the Biobank of Infectious Diseases rapidly established the COVID-19 collection comprised by plasma, serum and peripheral blood mononuclear cells samples obtained from people within the acute phase of the infection or who have already recovered. In only 6 months, 825 donors were enrolled, representing around 14,000 vials of biological material stored and available to researchers who might require it. In this line, 6 transfer agreements have been already performed to different groups belonging to national research institutions, while 3 are under evaluation. The transferred samples have allowed, for instance, the development of nationally produced serologic kits, which shows that the rapid establishment of this collection, under an efficient management system, represents a highly valuable tool in the response to this new disease.
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Humanos , Perfil de Saúde , Bancos de Espécimes Biológicos/organização & administração , Financiamento dos Sistemas de Saúde , COVID-19 , Acessibilidade aos Serviços de Saúde , Consentimento Livre e EsclarecidoRESUMO
BACKGROUND: Combined antiretroviral treatment (cART) for HIV infection is highly effective in controlling viral replication. However, it cannot achieve a sterilizing cure. Several strategies have been proposed to achieve a functional cure, some of them based on immune-mediated clearing of persistently infected cells. Here, we aimed at identifying factors related to CD8TC and CD4TC quality before cART initiation that associate with the persistence of CD8TC antiviral response after cART, inflammation levels, and the size of the viral reservoir. METHODS: Samples from 25 persons living with HIV were obtained before and after (15 months) cART initiation. Phenotype and functionality of bulk and HIV-specific T cells were assayed by flow cytometry ex vivo or after expansion in pre-cART or post-cART samples, respectively. Cell-Associated (CA) HIV DNA (total and integrated) and RNA (unspliced [US] and multiple spliced [MS]) were quantitated by real-time PCR on post-cART samples. Post-cART plasma levels of CXCL10 (IP-10), soluble CD14 (sCD14) and soluble CD163 (sCD163) were measured by ELISA. RESULTS: Pre-cART phenotype of CD8TCs and magnitude and phenotype of HIV-specific response correlated with the phenotype and functionality of CD8TCs post-cART. Moreover, the phenotype of the CD8TCs pre-cART correlated with markers of HIV persistence and inflammation post-cART. Finally, exhaustion and differentiation of CD4TCs pre-cART were associated with the composition of the HIV reservoir post-cART and the level of inflammation. CONCLUSIONS: Overall, this work provides data to help understand and identify parameters that could be used as markers in the development of immune-based functional HIV cure strategies.
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BACKGROUND: Hepatitis C virus (HCV) coinfection among people with human immunodeficiency virus (HIV) might perturb immune function and HIV persistence. We aimed to evaluate the impact of HCV clearance with direct-acting antivirals (DAAs) on immune activation and HIV persistence in HIV/HCV-coinfected individuals on antiretroviral therapy (ART). METHODS: In a prospective observational study, ART-treated participants with HIV/HCV coinfection received sofosbuvir/daclatasvirâ ±â ribavirin (nâ =â 19). Blood samples were collected before DAA therapy, at the end of treatment, and 12 months after DAA termination (12MPT). T- and natural killer (NK)-cell phenotype, soluble plasma factors, cell-associated (CA)-HIV deoxyribonucleic acid (DNA) forms (total, integrated, 2LTR), CA-unspliced (US) and multiple-spliced ribonucleic acid (RNA), and plasma HIV RNA were evaluated. RESULTS: Hepatitis C virus clearance was associated with (1) a downmodulation of activation and exhaustion markers in CD4+, CD8+ T, and NK cells together with (2) decreased plasma levels of Interferon gamma-induced protein 10 (IP10), interleukin-8 (IL-8), soluble (s)CD163 and soluble intercellular adhesion molecule (sICAM). Cell-associated US HIV RNA was significantly higher at 12MPT compared to baseline, with no change in HIV DNA or plasma RNA. CONCLUSIONS: Elimination of HCV in HIV/HCV-coinfected individuals alters immune function and the transcriptional activity of latently infected cells. This report provides insights into the effects of HCV coinfection in HIV persistence and regards coinfected subjects as a population in which HIV remission might prove to be more challenging.
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La disfunción inmune asociada a la infección por el virus de la inmunodeficiencia humana (VIH) es generada por una estimulación crónica del sistema inmune secundaria a la imposibilidad del organismo de erradicar el virus. La misma se encuentra exacerbada en el contexto de la coinfección por el virus de la hepatitis C (VHC). La inflamación sistémica producto de la coinfección por ambos virus genera un aumento de la morbilidad y mortalidad en los individuos afectados. Son varios los mediadores solubles de activación inmunológica, como IP-10, TNF-α, IL-6, IL-1ß (marcadores de inflamación sistémica); IL-17 (linfocitos T CD4+ Th17); IL-2, IFN-γ (linfocitos T CD4+ Th1); IL-8 (inducción de neutrofilia); CD23s, ICAMs, CD14s, CD163s (marcadores de activación de monocitos/macrófagos), niveles circulantes de lipopolisacárido (LPS) (translocación bacteriana); entre otros. Actualmente se necesitan más estudios para lograr definir cuáles serían los biomarcadores de progresión óptimos para el seguimiento de los individuos coinfectados por VIH/VHC. El objetivo de esta revisión es realizar una reseña sobre los mecanismos inmunopatológicos de la infección por VIH/VHC involucrados en la inflamación, daño hepático y su impacto en la morbimortalidad de los individuos coinfectados
The immune dysfunction associated with Human Immunodeficiency Virus (HIV) infection is generated by a chronic stimulation of the immune system, because of the inability to eradicate the virus from the host. This immune dysfunction is exacerbated in the context of coinfection with Hepatitis C Virus (HCV). Systemic inflammation caused by coinfection with both viruses generates an increase in morbidity and mortality in affected individuals. There are several soluble mediators of immunological activation, such as IP-10, TNF-α, IL-6, IL-1ß (systemic inflammation markers); IL-17 (CD4+ T cells Th17); IL-2, IFN-γ (CD4+ T cells Th1); IL-8 (neutrophilia); CD23s, ICAMs, CD14s, CD163s, lipopolysaccharide (LPS) (monocyte/macrophage activation markers and bacterial translocation); among others. Currently, more studies are needed to define optimal progression biomarkers for the follow-up of HIV/HCV coinfected individuals. In this review, we focus on the immunopathological mechanisms of HIV/HCV infection involved in inflammation, liver damage and its impact on the morbidity and mortality of affected individuals
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Humanos , Biomarcadores , Infecções por HIV/imunologia , Hepacivirus/imunologia , Coinfecção/imunologia , Hepatite/imunologia , Imunidade , Doenças do Sistema Imunitário , Inflamação/imunologiaRESUMO
BACKGROUND: The persistence of latently infected T cells remains the principal barrier to HIV cure. Understanding how the early immune responses shape persistence of HIV on antiretroviral therapy (ART) will be fundamental for potential eradication. Here, we aimed to determine the relationship between CD8 T-cell function and phenotype before therapy and HIV persistence on ART. METHODS: Blood samples from 29 individuals enrolled during primary HIV infection (at baseline and every 3 months up to 2 years post-ART initiation) were obtained. HIV-specific T-cell function and expression of the activation markers were evaluated before ART by flow cytometry. Cell-associated HIV DNA and unspliced (US)-RNA were quantified in purified CD4 T cells by real-time polymerase chain reaction. Data were analyzed using nonparametric statistics. RESULTS: Elevated immune activation, dominance of monofunctional CD8 T cells, and skewed distribution of memory profile were observed before ART. After ART initiation, HIV DNA and US-RNA levels rapidly diminished, reaching a plateau by 30 weeks after ART. The proportion of baseline HIV-specific effector memory and terminal effector CD8 T cells directly correlated with HIV DNA levels at 1 year after ART. A strong positive correlation was observed between the proportion of bulk and HIV-specific PD-1 CD8 T cells measured before ART and HIV DNA at 1 year after ART. CONCLUSIONS: A higher proportion of terminally differentiated CD8 T cells and increased PD1 expression were associated with HIV persistence on ART after treatment of primary infection. Thus, the quality of the early CD8 T-cell immune response may serve as a predictor of HIV persistence on ART.
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Linfócitos T CD8-Positivos/fisiologia , Infecções por HIV/tratamento farmacológico , Ativação Linfocitária/fisiologia , Receptor de Morte Celular Programada 1/fisiologia , Linfócitos T CD8-Positivos/virologia , Estudos de Coortes , Infecções por HIV/imunologia , Infecções por HIV/fisiopatologia , Humanos , Memória Imunológica , Ativação Linfocitária/efeitos dos fármacos , Prevenção Secundária , Resultado do Tratamento , Carga Viral/efeitos dos fármacosRESUMO
AIM: To characterize peripheral blood natural killer (NK) cells phenotypes by flow cytometry as potential biomarker of liver fibrosis in human immunodeficiency virus (HIV)/hepatitis C virus (HCV) coinfected patients. METHODS: Peripheral mononuclear cells from 24 HIV/HCV (HBV negative) coinfected and 5 HIV/HCV/HBV seronegative individuals were evaluated. HIV/HCV coinfected patients were divided in to groups: G1, patients with METAVIR F0-F2 and G2, patients with METAVIR F3-F4. NK surface cell staining was performed with: Anti-CD3(APC/Cy7), anti-CD56(PE/Cy5), anti-CD57(APC), anti-CD25(PE), anti-CD69(FITC), anti-NKp30(PE), anti-NKp46(PE/Cy7), anti-NKG2D(APC), anti-DNAM(FITC); anti-CD62L (PE/Cy7), anti-CCR7(PE), anti-TRAIL(PE), anti-FasL(PE), anti CD94(FITC). Flow cytometry data acquisition was performed on BD FACSCanto, analyzed using FlowJo software. Frequency of fluorescence was analyzed for all single markers. Clinical records were reviewed, and epidemiological and clinical data were obtained. RESULTS: Samples from 11 patients were included in G1 and from 13 in G2. All patients were on ARV, with undetectable HIV viral load. Liver fibrosis was evaluated by transient elastography in 90% of the patients and with biopsy in 10% of the patients. Mean HCV viral load was (6.18 ± 0.7 log10). Even though, no major significant differences were observed between G1 and G2 regarding NK surface markers, it was found that patients with higher liver fibrosis presented statistically lower percentage of NK cells than individual with low to mild fibrosis and healthy controls (G2: 5.4% ± 2.3%, G1: 12.6% ± 8.2%, P = 0.002 and healthy controls 12.2% ± 2.7%, P = 0.008). It was also found that individuals with higher liver fibrosis presented lower CD4 LT count than those from G1 (G2: 521 ± 312 cells/µL, G1: 770 ± 205 cells/µL; P = 0.035). CONCLUSION: Higher levels of liver fibrosis were associated with lower percentage of NK cells and LTCD4+ count; and they may serve as noninvasive biomarkers of liver damage.
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INTRODUCTION: Hepatitis C virus (HCV) represents a major health concern, as nearly 3 million people become newly infected by this pathogen annually. The majority of infected individuals fail to clear the virus, and chronicity is established. Chronic HCV patients are at high risk for liver disease, ranging from mild fibrosis to cirrhosis and severe hepatocellular carcinoma. Over the last few years, the development of multiple direct acting antivirals (DAA) have revolutionized the HCV infection treatment, demonstrating cure rates higher than 90%, and showing less side effects than previous interferon-based regimens. Areas covered: Besides liver, HCV infection affects a variety of organs, therefore inducing diverse extrahepatic manifestations. This review covers clinical, experimental, and epidemiological publications regarding systemic manifestations of HCV, as well as recent studies focused on the effect of DAA in such conditions. Expert commentary: Though further research is needed; available data suggest that HCV eradication is often associated with the improvement of extrahepatic symptoms. Therefore, the emergence of DAA would offer the opportunity to treat both HCV infection and its systemic manifestations, requiring shorter treatment duration and driving minor adverse effects.
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Antivirais/uso terapêutico , Hepacivirus/efeitos dos fármacos , Hepatite C Crônica/complicações , Hepatite C Crônica/tratamento farmacológico , Carcinoma Hepatocelular/etiologia , Carcinoma Hepatocelular/virologia , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/virologia , Doenças do Sistema Endócrino/etiologia , Doenças do Sistema Endócrino/virologia , Hepatite C Crônica/virologia , Humanos , Nefropatias/etiologia , Nefropatias/virologia , Cirrose Hepática/etiologia , Cirrose Hepática/virologia , Transtornos Linfoproliferativos/etiologia , Transtornos Linfoproliferativos/virologia , Doenças Musculoesqueléticas/etiologia , Doenças Musculoesqueléticas/virologiaRESUMO
Improved efficacy of neoadjuvant endocrine-targeting therapies in luminal breast carcinomas could be achieved with optimal use of pathway targeting agents. In a mouse model of ductal breast carcinoma we identify a tumor regressive stromal reaction that is induced by neoadjuvant endocrine therapy. This reparative reaction is characterized by tumor neovascularization accompanied by infiltration of immune cells and carcinoma-associated fibroblasts that stain for phosphorylated ribosomal protein S6 (pS6), downstream the PI3K/Akt/mTOR pathway. While tumor variants with higher PI3K/Akt/mTOR activity respond well to a combination of endocrine and PI3K/Akt/mTOR inhibitors, tumor variants with lower PI3K/Akt/mTOR activity respond more poorly to the combination therapy than to the endocrine therapy alone, associated with inhibition of stromal pS6 and the reparative reaction. In human breast cancer xenografts we confirm that such differential sensitivity to therapy is primarily determined by the level of PI3K/Akt/mTOR in tumor cells. We further show that the clinical response of breast cancer patients undergoing neoadjuvant endocrine therapy is associated with the reparative stromal reaction. We conclude that tumor level and localization of pS6 are associated with therapeutic response in breast cancer and represent biomarkers to distinguish which tumors will benefit from the incorporation of PI3K/Akt/mTOR inhibitors with neoadjuvant endocrine therapy.
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Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/enzimologia , Carcinoma Ductal de Mama/tratamento farmacológico , Carcinoma Ductal de Mama/enzimologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Idoso , Idoso de 80 Anos ou mais , Androstadienos/farmacologia , Animais , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Moduladores de Receptor Estrogênico/farmacologia , Feminino , Humanos , Neoplasias Mamárias Experimentais/tratamento farmacológico , Neoplasias Mamárias Experimentais/enzimologia , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Inibidores de Fosfoinositídeo-3 Quinase , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Transdução de Sinais , Células Estromais/enzimologia , Células Estromais/patologia , Wortmanina , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Using a model of medroxyprogesterone acetate (MPA)-induced mouse mammary tumors that transit through different stages of hormone dependence, we previously reported that the activation of the phosphatidylinositol 3-kinase (PI3K)/AKT (protein kinase B) pathway is critical for the growth of hormone-independent (HI) mammary carcinomas but not for the growth of hormone-dependent (HD) mammary carcinomas. The objective of this work was to explore whether the activation of the PI3K/AKT pathway is responsible for the changes in tumor phenotype and for the transition to autonomous growth. We found that the inhibition of the PI3K/AKT/mTOR (mammalian target of rapamycin) pathway suppresses HI tumor growth. In addition, we were able to induce mammary tumors in mice in the absence of MPA by inoculating HD tumor cells expressing a constitutively active form of AKT1, myristoylated AKT1 (myrAKT1). These tumors were highly differentiated and displayed a ductal phenotype with laminin-1 and cytokeratin 8 expression patterns typical of HI tumors. Furthermore, myrAKT1 increased the tumor growth of IBH-6 and IBH-7 human breast cancer cell lines. In the estrogen-dependent IBH-7 cell line, myrAKT1 induced estrogen-independent growth accompanied by the expression of the adhesion markers focal adhesion kinase and E-cadherin. Finally, we found that cells expressing myrAKT1 exhibited increased phosphorylation of the progesterone receptor at Ser190 and Ser294 and of the estrogen receptor α at Ser118 and Ser167, independently of exogenous MPA or estrogen supply. Our results indicate that the activation of the PI3K/AKT/mTOR pathway promotes tissue architecture remodeling and the activation of steroid receptors.
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Neoplasias Mamárias Experimentais/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Animais , Caderinas/biossíntese , Diferenciação Celular , Linhagem Celular Tumoral , Proliferação de Células , Feminino , Proteína-Tirosina Quinases de Adesão Focal/biossíntese , Humanos , Queratina-8/biossíntese , Laminina/biossíntese , Neoplasias Mamárias Experimentais/induzido quimicamente , Acetato de Medroxiprogesterona/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Inibidores de Fosfoinositídeo-3 Quinase , Fosforilação , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Transdução de Sinais , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/metabolismoRESUMO
BACKGROUND: A significant proportion of breast cancer patients face failure of endocrine therapy due to the acquisition of endocrine resistance. We have explored mechanisms involved in such disease progression by using a mouse breast cancer model that is induced by medroxyprogesterone acetate (MPA). These tumors transit through different stages of hormone sensitivity. However, when cells from tumor variants were seeded on plastic, all were stimulated by progestins and inhibited by antiprogestins such as RU486. Furthermore, cells from a RU486-resistant tumor variant recovered antiprogestin sensitivity. HYPOTHESIS: A three-dimensional (3D) culture system, by maintaining differential cellular organization that is typical of each tumor variant, may allow for the maintenance of particular hormone responses and thus be appropriate for the study of the effects of specific inhibitors of signaling pathways associated with disease progression. METHOD: We compared the behavior of tumors growing in vivo and cancer cells ex vivo (in 3D Matrigel). In this system, we evaluated the effects of kinase inhibitors and hormone antagonists on tumor growth. PRINCIPAL FINDINGS: LY294002, a PI3K/AKT pathway inhibitor, decreased both tumor growth in vivo and cell survival in Matrigel in MPA-independent tumors with higher AKT activity. Induction of cell death by anti-hormones such as ICI182780 and ZK230211 was more effective in MPA-dependent tumors with lower AKT activity. Inhibition of MEK with PD98059 did not affect tumor growth in any tested variant. Finally, while Matrigel reproduced differential responsiveness of MPA-dependent and -independent breast cancer cells, it was not sufficient to preserve antiprogestin resistance of RU486-resistant tumors. CONCLUSION: We demonstrated that the PI3K/AKT pathway is relevant for MPA-independent tumor growth. Three-dimensional cultures were useful to test the effects of kinase inhibitors on breast cancer growth and highlight the need for in vivo models to validate experimental tools used for selective therapeutic targeting.