IRF2-INPP4B-mediated autophagy suppresses apoptosis in acute myeloid leukemia cells

BACKGROUND: The present study aimed to investigate the underlying role of interferon-regulatory factor 2 (IRF2)-inositol polyphosphate-4-phosphatase, type-II (INPP4B) axis in the regulation of autophagy in acute myeloid leukemia (AML) cells. METHODS: Quantitative real time PCR (QRT-PCR) and western blot were performed to determine the expression levels of IRF2, INPP4B and autophagy-related markers in AML cell lines. Autophagy was assessed by elevated Beclin-1 expression, the conversion of light chain 3 (LC3)-I to LC3-II, downregulated p62 expression and green fluorescent protein (GFP)-LC3 puncta formation. The colony formation and apoptosis assays were performed to determine the effects of IRF2 and INPP4B on the growth of AML cells. RESULTS: IRF2 and INPP4B were highly expressed in AML cell lines, and were positively correlated with autophagy-related proteins. Overexpression of IRF2 or INPP4B stimulated autophagy of AML cells, whereas inhibition of IRF2 or INPP4B resulted in the attenuation of autophagy. More importantly, IRF2 or INPP4B overexpression reversed autophagy inhibitor, 3-methyladenine (3-MA)-induced proliferation-inhibitory and pro-apoptotic effects, while IRF2 or INPP4B silencing overturned the proliferation-promoting and anti-apoptotic effects of autophagy activator rapamycin. CONCLUSION: IRF2-INPP4B signaling axis attenuated apoptosis through induction of autophagy in AML cells.

Chronic Hepatitis C treatment for genotype 2 or 3 in Brazil: cost effectiveness analysis of peginterferon plus ribavirin as first choice treatment

Brazilian Guidelines to HCV treatment (2007) recommended that the first choice treatment for patients with chronic hepatitis C (CHC) and genotype 2 or 3 is interferon alpha (IFN) plus ribavirin (RBV) for 24 weeks. The aim of this study is compare the cost and effectiveness to Hepatitis C treatment in patients with genotype 2 or 3 of peginterferon alpha (PEG) as the first choice of treatment within PEG for those that do not respond to IFN. The target population is CHC patients with genotype 2 or 3 in Brazil. The interventions are: PEG-SEC (first IFN plus RBV for 24 weeks, after, for non-responders and relapsers subsequently PEG plus RBV for 48 weeks); PEG-FIRST24 (PEG+RBV for 24 weeks). The type of the study is cost-effectiveness analysis. The data sources are: Effectiveness data from meta-analysis conducted on the Brazilian population. Treatment cost from Brazilian micro costing study is converted into USD (2010). The perspective is the Public Health System. The outcome measurements are Sustained Viral Response (SVR) and costs. PEG-FIRST24 (SVR: 87.8%, costs: USD 8,338.27) was more effective and more costly than PEG-SEC (SVR: 79.2%, costs: USD 5,852.99). The sensitivity analyses are: When SVR rates with IFN was less than 30% PEG-FIRST is dominant. On the other hand, when SVR with IFN was more then 75% PEG-SEC is dominant (SVR=88.2% and costs USD $ 3,753.00). PEG-SEC is also dominant when SVR to PEG24 weeks was less than 54%. In the Brazilian context, PEG-FIRST is more effective and more expensive than PEG-SEC. PEG-SEC could be dominant when rates of IFN therapy are higher than 75% or rates of PEG24 therapy are lower than 54%.

O protocolo brasileiro de tratamento da Hepatite C (2007) recomendava como primeira escolha para pacientes com hepatite C crônica e portadores de genótipo 2 ou 3 o tratamento com interferona alfa (IFN) associada à ribavirina (RBV), por 24 semanas. O objetivo deste estudo é comparar o custo e a efetividade para pacientes com hepatite C crônica e portadores do genótipo 2 ou 3 o uso de peguinterferon (PEG) como primeiro escolha com o PEG como secunda escolha para aqueles que não responderam ao tratamento com IFN. A população alvo compreende pacientes com hepatite C crônica portadores de genótipo 2 ou 3 no Brasil. As intervenções são: PEG-SEC (IFN + RBV por 24 semanas, para os não respondedores e recidivantes tratamento subsequente com PEG + RBV por 48 semanas; PEG-FIRST24 (PEG + RBV por 24 semanas). O tipo de estudo envolvido é Análise de Custo Efetividade. Os dados de efetividade são provenientes de um metanálise de estudos brasileiros e os dados de custo do tratamento de um estudo de custo do contexto brasileiro. A perspectiva é o Sistema Público de Saúde. Os desfechos avaliados foram Resposta Viral Sustentada (RVS) e Custos. PEG-FIRST24 (RVS: 87,8%, costs: USD 8.338,27) foi mais efetivo e apresentou maior custo que PEG-SEC (RVS: 79,2%, custo USD 5.852,99). A análise de sensibilidade demonstrou que PEG-SEC é dominado por PEG-FIRST24 quando RVS com IFN for menor que 30%. Por outro lado, quando RVS com IFN for maior que 75% PEG-SEC é dominante (RVS=88.2% e custo USD $ 3.753,00). PEG-SEC é também dominante quando RVS para PEG24 for menor que 54%. Conclusão: No contexto brasileiro, PEG-FIRST é mais efetivo e mais custoso que PEG-SEC. PEG-SEC poderia ser dominante quando as taxas de RVS do tratamento com IFN forem superiores a 75% ou as taxas de PEG24 forem inferiores a 54%.

Interferon regulatory factor-1 exerts inhibitory effect on neointimal formation after vascular injury / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the effect of interferon regulatory factors (IRFs) on neointimal formation after vascular injury in the mouse, and its possible mechanism.</p><p><b>METHODS</b>Vascular injury was induced by polyethylene cuff placement around the left femoral artery of IRF-1-deficient mice and C57BL/6J mice. The mRNA expressions of IRF-1, IRF-2, angiotensin II type 2 (AT2) receptor, interleukin-1 beta converting enzyme (ICE), inducible nitric oxide synthase (iNOS) were detected by RT-PCR and immunohistochemical staining.</p><p><b>RESULTS</b>Neointimal formation after vascular injury was significantly greater in IRF-1-deficient mice than that in C57BL/6J mice (P<0.05). In contrast, TUNEL-positive nuclei to total nuclei in the neointima and media in vascular smooth muscle cell (VSMC) in the injured artery significantly attenuated in IRF-1-deficient mice compared to C57BL/6J mice (P<0.05). The expressions of AT2 receptor as well as pro-apoptotic genes such as ICE and iNOS in C57BL/6J mice were up-regulated in response to vascular injury, but this upregulation was attenuated in IRF-1-deficient mice.</p><p><b>CONCLUSIONS</b>Our results suggest that IRF-1 induces VSMC apoptosis and inhibits neointimal formation after vascular injury at least partly due to the upregulation of AT2 receptor, ICE and iNOS expressions. These results indicate that IRF-1 exerts an inhibitory effect on neointimal formation through the induction of apoptosis in VSMCs.</p>

IRF-1 and IRF-2 as regulators of the interferon system and cell growth.

Interferons (IFNs) are families of cytokines which have been discovered and extensively characterized in the context of host defense against viral infections. We have discovered two structurally related transcription factors, Interferon regulatory factor-1 (IRF-1) and IRF-2. These two factors, however, function not only as regulators of the IFN system, but are also key transcription factors in the regulation of cell cycle and apoptosis. These studies uncover a complex gene transcription network, by which the fate of cellular responses are determined depending on how the IRF transcription factors function in conjunction with other factors, and on the promoters of distinct genes under different conditions of the cells.