Azidothymidine is effective against human multiple myeloma: a new use for an old drug?

Azidothymidine (AZT) is an antiretroviral drug that affects cell proliferation, apoptosis, and the NF-κB pathway. As multiple myeloma (MM) presents with constitutive activation of NF-κB, we analyzed the effect of AZT on human MM cell lines. We evaluated the cytotoxic effect of AZT in human MM cell lines sensitive (8226/S) or resistant to doxorubicin (8226/DX5) and human T cell lymphoblast-like cells, uterine sarcoma cells, and HUVEC using MTT assay. Cytotoxicity was also evaluated in vivo in nude mice xenografted with 8226/S tumor. The effect of AZT on the expression of genes involved in cell proliferation, apoptosis, angiogenesis, and the NF-κB pathway was analyzed in the xenografts using real-time polymerase chain reaction. AZT was effective against both 8226/S and 8226/DX5 cells in a dose and time-dependent manner (p = 0.02) in vitro and promoted cell cycle arrest in S phase in these cells. The tumor volume was lower in mice treated with AZT compared to untreated mice (p = 0.0003). AZT down-regulated the pro-proliferative genes encoding AKT1, MYC, STAT1, MAPK8, MAPK9, CCL-3, Bcl-3, and cyclin D2; pro-angiogenenic genes encoding VEGF and IL8; and genes involved in cell adhesion (ICAM1 and FN1) and the NF-κB pathway. AZT up-regulated the expression of tumor suppressor gene FOXP1 and the pro-apoptotic genes encoding BID, Bcl-10, and caspase-8. Thus, we demonstrated the cytotoxic effect of AZT in human MM cell lines for the first time. Our data may provide the rationale for future clinical trials of AZT for treating MM.

Caracterização imunofenotípica de linfócitos B de memória na deficiência de IgA e imunodeficiência comum variável / Immunophenotypical characterization of memory B Iymphocytes in IgA deficiency and common variable immunodeficiency

Objetivo: A progressão da deficiência de IgA (DIgA) para imunodeficiência comum variável (ICV) tem sido relatada, embora não constitua regra geral. Postula-se que a associação com doenças autoimunes (DAIs) constitua fator de risco para tal progressão. Embora a fisiopatologia da ICV não esteja esclarecida, a redução de células B de memória class-switched (CD27+IgG-IgM-) tem sido relacionada a sua maior associação com autoimunidade. Por outro lado, na DIgA a persistência de células B imaturas IgM+ IgD+ foi associada à progressão para ICV. O objetivo foi comparar em pacientes com DIgA e ICV populações de células B de memória e correlacionar estas populações celulares à presença de DAIs em ambos grupos. Métodos: O estudo incluiu 56 pacientes adultos com DIgA ou ICV igualmente distribuídos em 4 grupos de acordo com a presença ou ausência de DAIs. As seguintes subpopulações de células B foram determinadas por citometria de fluxo de quatro cores: células B naive (CD19+IgM+), células B de memória c/ass-switched (CD27+IgM-IgD-) e células B de memória imaturas (CD27+IgM+ ou CD27+IgD+). Resultados: Os valores de células B naive e de células de memória c1ass-switched foram similares nos quatro grupos estudados. Os pacientes com DIgA ou ICV e DAIs associadas apresentaram valores igualmente aumentados de células B de memória imaturas CD27+IgM+ e CD27+IgD+ quando comparados a pacientes sem autoimunidade. Conclusões: Neste estudo foi demonstrado pela primeira vez persistência de células B de memória imaturas em pacientes adultos com DIgA e ICV associadas a doenças autoimunes. Especula-se se a persistência destas células possa constituir fator de risco para a progressão de DIgA para ICV.

Objective: Progression from IgA deficiency (IgAD) to common variable immunodeficiency (CVID) has been reported in some patients, but is not a general rule. It is postulated if association with autoimmune diseases (AIDs) could be risk factor for such progression. While the pathophysiology of CVID remains elusive, decreased numbers of classic (class-switched) memory B cells (CD27+IgG-IgM-) was correlated with increased rates of autoimmune features. By other hand, persistence of immature B cells (IgM+ IgD+) in IgA deficiency patients was correlated to progression from DIgA to CVID. The aim of this study was to compare memory B cell subpopulations in IgAD and CVID patients, and to assess the relationship between these populations and the presence of autoimmune diseases in both group of patients. Methods: This study included 56 adult patients with IgAD or CVID distributed in four groups according to the presence or absence of AIDs. The following B cell populations were determined by lymphocyte immunophenotyping by four-colour flow cytometry: narve B cells (CD19+IgM+), c1ass-switched memory B cells (CD27+IgM-IgD-) and immature B memory cells (CD27+IgM+ or CD27+IgD+). Results: Naive B cell and c1ass-switched memory B cells (CD27+IgG-IgM-) numbers were similar in all groups studied. IgAD and CVID patients with associated AIDs presented higher values of immature B cells (CD27 IgM+ and CD27+ IgD+) than patients without associated AIDs. Conclusions: This study reported for the first time the persistence of immature memory B cells in adult IgAD and CVID patients associated to autoimmune diseases. We speculate if persistence of immature B cells may constitute a rlsk factor for progression of IgAD to CVID.