RESUMO
To design rational therapies for JAK2-driven hematological malignancies, we functionally dissected the key survival pathways downstream of hyperactive JAK2. In tumors driven by mutant JAK2, Stat1, Stat3, Stat5, and the Pi3k and Mek/Erk pathways were constitutively active, and gene expression profiling of TEL-JAK2 T-ALL cells revealed the upregulation of prosurvival Bcl-2 family genes. Combining the Bcl-2/Bcl-xL inhibitor ABT-737 with JAK2 inhibitors mediated prolonged disease regressions and cures in mice bearing primary human and mouse JAK2 mutant tumors. Moreover, combined targeting of JAK2 and Bcl-2/Bcl-xL was able to circumvent and overcome acquired resistance to single-agent JAK2 inhibitor treatment. Thus, inhibiting the oncogenic JAK2 signaling network at two nodal points, at the initiating stage (JAK2) and the effector stage (Bcl-2/Bcl-xL), is highly effective and provides a clearly superior therapeutic benefit than targeting just one node. Therefore, we have defined a potentially curative treatment for hematological malignancies expressing constitutively active JAK2.
Assuntos
Resistencia a Medicamentos Antineoplásicos , Janus Quinase 2/antagonistas & inibidores , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Proteína bcl-X/antagonistas & inibidores , Animais , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/genética , Proteína 11 Semelhante a Bcl-2 , Compostos de Bifenilo/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular , Perfilação da Expressão Gênica , Humanos , Janus Quinase 2/genética , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos SCID , Transplante de Neoplasias , Nitrilas , Nitrofenóis/farmacologia , Piperazinas/farmacologia , Proteínas Proto-Oncogênicas/genética , Pirazóis/farmacologia , Pirimidinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Sulfonamidas/farmacologia , Transplante Heterólogo , Proteína bcl-X/genéticaRESUMO
Formation of germ cell derived teratomas occurs in mice of the 129/SvJ strain, but not in C57Bl/6 inbred or CD1 outbred mice. Despite this, there have been few comparative studies aimed at determining the similarities and differences between teratoma susceptible and non-susceptible mouse strains. This study examines the entry of fetal germ cells into the male pathway and mitotic arrest in 129T2/SvJ mice. We find that although the entry of fetal germ cells into mitotic arrest is similar between 129T2/SvJ, C57Bl/6 and CD1 mice, there were significant differences in the size and germ cell content of the testis cords in these strains. In 129T2/SvJ mice germ cell mitotic arrest involves upregulation of p27(KIP1), p15(INK4B), activation of RB, the expression of male germ cell differentiation markers NANOS2, DNMT3L and MILI and repression of the pluripotency network. The germ-line markers DPPA2 and DPPA4 show reciprocal repression and upregulation, respectively, while FGFR3 is substantially enriched in the nucleus of differentiating male germ cells. Further understanding of fetal male germ cell differentiation promises to provide insight into disorders of the testis and germ cell lineage, such as testis tumour formation and infertility.