Cerebral infarction as the first symptom in acute promyelocytic leukemia: A case report and literature review.

In the clinical settings, disseminated intravascular coagulation (DIC) and complications such as hemorrhage are commonly seen in acute promyelocytic leukemia patients, whereas thrombosis is rarely reported. We reported a case here that the patient presented with cerebral infarction as the first manifestation. During the admission, the patient encountered differentiation syndrome, pulmonary embolism, pulmonary hemorrhage, and myocardial ischemia, as well as bleeding and thrombosis complications.

RAF-1/MEK/ERK pathway regulates ATRA-induced differentiation in acute promyelocytic leukemia cells through C/EBPβ, C/EBPε and PU.1.

MEK/ERK signal pathway was required for the differentiation of granulocytes, megakaryocytes and erythrocytes. Recently, MEK/ERK cascade was reported to be involved in all-trans retinoic acid (ATRA) induced differentiation in acute promyelocytic leukemia (APL) cells. However, the upstream and downstream molecules of MEK/ERK signal pathway in this cell model remains to be elucidated.

Combined staurosporine and retinoic acid induces differentiation in retinoic acid resistant acute promyelocytic leukemia cell lines.

All-trans retinoic acid (ATRA) resistance has been a critical problem in acute promyelocytic leukemia (APL) relapsed patients. In ATRA resistant APL cell lines NB4-R1 and NB4-R2, the combination of staurosporine and ATRA synergized to trigger differentiation accompanied by significantly enhanced protein level of CCAAT/enhancer binding protein ε (C/EBPε) and C/EBPβ as well as the phosphorylation of mitogen-activated protein (MEK) and extracellular signal-regulated kinase (ERK). Furthermore, attenuation of the MEK activation blocked not only the differentiation but also the increased protein level of C/EBPε and C/EBPβ.