buparlisib and Burkitt-Lymphoma

Novel insights into the pathophysiology of primary central nervous system lymphoma (PCNSL) have identified the B-cell receptor and Toll-like receptor pathway as well as immune evasion and suppressed tumor immune microenvironment as a key mechanism in the pathogenesis of PCNSL. Small molecules and novel agents targeting these aberrant pathways have been introduced into clinical trials targeting the recurrent or refractory PCNSL patient population. Agents like the Bruton tyrosine kinase (BTK) inhibitor ibrutinib or immunomodulatory drugs (IMiDs) like pomalidomide and lenalidomide have shown promising high response rates in the salvage setting. Here, we give an overview about the recent, exciting developments in PCNSL and summarize the results of clinical trials using novel agents in the recurrent and refractory salvage setting, which include immune checkpoint inhibitors, IMiDs, as well as BTK, phosphatidylinositol-3 kinase, and mammalian target of rapamycin inhibitors.

Topics: Adenine; Agammaglobulinaemia Tyrosine Kinase; Aminopyridines; Antineoplastic Agents, Immunological; Burkitt Lymphoma; Central Nervous System Neoplasms; Humans; Immunologic Factors; Lenalidomide; Lymphoma, Large B-Cell, Diffuse; Lymphoma, T-Cell; Morpholines; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Piperidines; Protein Kinase Inhibitors; Pyrazoles; Pyrimidines; Rituximab; Salvage Therapy; Thalidomide; Toll-Like Receptors; TOR Serine-Threonine Kinases; Tumor Escape

This study was conducted to define the synergistic effect of the PI3K inhibitor BKM120 with the pan-Aurora kinase inhibitor danusertib and the potential mechanism of resistance to the combined inhibitor treatment in Burkitt lymphoma cell lines. The combination of danusertib and BKM120 showed a synergistic effect on Namalwa cells but not on BJAB cells. The combined treatment led to ERK hyperactivation and induced IL-6 secretion in BJAB cells but not in Namalwa cells. A blockade of ERK signaling with trametinib suppressed the combination treatment-induced ERK activation, reduced IL-6 mRNA expression, and downregulated IL-6R mRNA expression, resulting in an improvement in the antitumor effect. We stepwise treated Namalwa cells with both inhibitors using on-and-off treatment cycles and found that Namalwa cells gained chemoresistance by activating the ERK/IL-6 feedback loop, suggesting that the ERK-dependent IL-6 positive feedback loop can compensate for AKT inactivation and is closely associated with adaptive resistance and relapse.

Topics: Aminopyridines; Benzamides; Burkitt Lymphoma; Cell Line, Tumor; Cell Survival; Drug Resistance, Neoplasm; Drug Synergism; Extracellular Signal-Regulated MAP Kinases; Humans; Interleukin-6; Morpholines; Protein Kinase Inhibitors; Pyrazoles; Signal Transduction