No abstract

Key Points VCAM-1/VLA-4 triggers reciprocal NF-κB activation in leukemia and stromal cells and mediates cross-talk between leukemia and stromal cells. VCAM-1/VLA-4 and NF-κB signaling plays a pivotal role in the development of leukemia chemoresistance.

Mesenchymal stem cells (MSCs) are progenitors of connective tissues, which have emerged as important tools for tissue engineering due to their differentiation potential along various cell types. In recent years, accumulating evidence has suggested that the regulation of mitochondria dynamics and function is essential for successful differentiation of MSCs. In this paper, we review and provide an integrated view on the role of mitochondria in MSC differentiation. The mitochondria are maintained at a relatively low activity level in MSCs, and upon induction, mtDNA copy number, protein levels of respiratory enzymes, the oxygen consumption rate, mRNA levels of mitochondrial biogenesis-associated genes, and intracellular ATP content are increased. The regulated level of mitochondrial ROS is found not only to influence differentiation but also to contribute to the direction determination of differentiation. Understanding the roles of mitochondrial dynamics during MSC differentiation will facilitate the optimization of differentiation protocols by adjusting biochemical properties, such as energy production or the redox status of stem cells, and ultimately, benefit the development of new pharmacologic strategies in regenerative medicine.

Lenalidomide-rituximab therapy is effective in grade 1-2 follicular and mantle cell lymphoma, but its efficacy in diffuse large B-cell lymphoma (DLBCL), transformed large cell lymphoma (TL) and grade 3 follicular lymphoma (FLG3) is unknown. In this phase II trial, 45 patients with relapsed or refractory DLBCL (n=32), TL (n=9) or FLG3 (n=4) who had received 1-4 prior lines of treatment were given 20 mg oral lenalidomide on days 1-21 of each 28-day cycle, and intravenous rituximab (375 mg/m(2)) weekly during cycle 1. Grade 3/4 hematological toxicities included neutropenia (53%), lymphopenia (40%), thrombocytopenia (33%), leukopenia (27%) and anemia (18%), with a median follow-up time of 29.1 months (range 14.7-52.0 months). Overall response (OR) rate was 33%; median response duration was 10.2 months. Median progression-free survival (PFS) and overall survival (OS) were 3.7 and 10.7 months, respectively. Nine of the 15 responding patients (three partial response (PR), six complete response (CR)) proceeded with stem cell transplantation (SCT) and were censored at the time of transplantation. When data were analyzed without censoring, median PFS remained 3.7 months and response duration increased to 30.9 months. Rituximab plus oral lenalidomide is well tolerated and effective for patients with relapsed/refractory DLBCL and TL. SCT after lenalidomide-rituximab is associated with prolonged response duration.