RESUMO
Protein kinase Cß (PKCß) expressed in mammalian cells as two splice variants, PKCßI and PKCßII, functions in the B cell receptor (BCR) signaling pathway and contributes to B cell development. We investigated the relative role of PKCßII in B cells by generating transgenic mice where expression of the transgene is directed to these cells using the Eµ promoter (Eµ-PKCßIItg). Our findings demonstrate that homozygous Eµ-PKCßIItg mice displayed a shift from IgD+IgMdim toward IgDdimIgM+ B cell populations in spleen, peritoneum and peripheral blood. Closer examination of these tissues revealed respective expansion of marginal zone (MZ)-like B cells (IgD+IgM+CD43negCD21+CD24+), increased populations of B-1 cells (B220+IgDdimIgM+CD43+CD24+CD5+), and higher numbers of immature B cells (IgDdimIgMdimCD21neg) at the expense of mature B cells (IgD+IgM+CD21+). Therefore, the overexpression of PKCßII, which is a phenotypic feature of chronic lymphocytic leukaemia cells, can skew B cell development in mice, most likely as a result of a regulatory influence on BCR signaling.
Assuntos
Linfócitos B/enzimologia , Regulação Enzimológica da Expressão Gênica , Regulação Leucêmica da Expressão Gênica , Leucemia Linfocítica Crônica de Células B/enzimologia , Proteínas de Neoplasias/biossíntese , Proteína Quinase C beta/biossíntese , Animais , Antígenos CD/genética , Antígenos CD/metabolismo , Linfócitos B/patologia , Imunoglobulina D/genética , Imunoglobulina D/metabolismo , Imunoglobulina M/genética , Imunoglobulina M/metabolismo , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/patologia , Camundongos , Camundongos Transgênicos , Proteínas de Neoplasias/genética , Proteína Quinase C beta/genética , Receptores de Antígenos de Linfócitos B/genética , Receptores de Antígenos de Linfócitos B/metabolismo , Transdução de SinaisRESUMO
AIMS: To reassess the prognostic validity of immunohistochemical markers and algorithms identified in the CHOP era in immunochemotherapy-treated diffuse large B cell lymphoma patients. METHODS AND RESULTS: The prognostic significance of immunohistochemical markers (CD10, Bcl-6, Bcl-2, MUM1, Ki-67, CD5, GCET1, FoxP1, LMO2) and algorithms (Hans, Hans*, Muris, Choi, Choi*, Nyman, Visco-Young, Tally) was assessed using clinical diagnostic blocks taken from an unselected, population-based cohort of 190 patients treated with R-CHOP. Dichotomizing expression, low CD10 (<10%), low LMO2 (<70%) or high Bcl-2 (≥80%) predicted shorter overall survival (OS; P = 0.033, P = 0.010 and P = 0.008, respectively). High Bcl-2 (≥80%), low Bcl-6 (<60%), low GCET1 (<20%) or low LMO2 (<70%) predicted shorter progression-free survival (PFS; P = 0.001, P = 0.048, P = 0.045 and P = 0.002, respectively). The Hans, Hans* and Muris classifiers predicted OS (P = 0.022, P = 0.037 and P = 0.011) and PFS (P = 0.021, P = 0.020 and P = 0.004). The Choi, Choi* and Tally were associated with PFS (P = 0.049, P = 0.009 and P = 0.023). In multivariate analysis, the International Prognostic Index (IPI) was the only independent predictor of outcome (OS; HR: 2.60, P < 0.001 and PFS; HR: 2.91, P < 0.001). CONCLUSIONS: Results highlight the controversy surrounding immunohistochemistry-based algorithms in the R-CHOP era. The need for more robust markers, applicable to the clinic, for incorporation into improved prognostic systems is emphasized.