Inhibition of glutaminase-1 in DLBCL potentiates venetoclax-induced antitumor activity by promoting oxidative stress.

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma in adults, but first-line immunochemotherapy fails to produce a durable response in about one-third of the patients. Because tumor cells often reprogram their metabolism, we investigated the importance of glutaminolysis, a pathway converting glutamine to generate energy and various metabolites, for the growth of DLBCL cells. Glutaminase-1 (GLS1) expression was robustly detected in DLBCL biopsy samples and cell lines. Both pharmacological inhibition and genetic knockdown of GLS1 induced cell death in DLBCL cells regardless of their subtype classification, whereas primary B cells remained unaffected. Interestingly, GLS1 inhibition resulted not only in reduced levels of intermediates of the tricarboxylic acid cycle but also in a strong mitochondrial accumulation of reactive oxygen species. Supplementation of DLBCL cells with α-ketoglutarate or with the antioxidant α-tocopherol mitigated oxidative stress and abrogated cell death upon GLS1 inhibition, indicating an essential role of glutaminolysis in the protection from oxidative stress. Furthermore, the combination of the GLS1 inhibitor CB-839 with the therapeutic BCL2 inhibitor ABT-199 not only induced massive reactive oxygen species (ROS) production but also exhibited highly synergistic cytotoxicity, suggesting that simultaneous targeting of GLS1 and BCL2 could represent a novel therapeutic strategy for patients with DLBCL.

Is Mistletoe Treatment Beneficial in Invasive Breast Cancer? A New Approach to an Unresolved Problem.

BACKGROUND/AIM: In this retrospective study, we compared breast cancer patients treated with and without mistletoe lectin I (ML-I) in addition to standard breast cancer treatment in order to determine a possible effect of this complementary treatment. PATIENTS AND METHODS: This study included 18,528 patients with invasive breast cancer. Data on additional ML-I treatments were reported for 164 patients. We developed a "similar case" method with a distance measure retrieved from the beta variable in Cox regression to compare these patients, after stage adjustment, with their non-ML-1 treated counterparts in order to answer three hypotheses concerning overall survival, recurrence free survival and life quality. RESULTS: Raw data analysis of an additional ML-I treatment yielded a worse outcome (p=0.02) for patients with ML treatment, possibly due to a bias inherent in the ML-I-treated patients. Using the "similar case" method (a case-based reasoning approach) we could not confirm this harm for patients using ML-I. Analysis of life quality data did not demonstrate reliable differences between patients treated with ML-I treatment and those without proven ML-I treatment. CONCLUSION: Based on a "similar case" model we did not observe any differences in the overall survival (OS), recurrence-free survival (RFS), and quality of life data between breast cancer patients with standard treatment and those who in addition to standard treatment received ML-I treatment.

New targeted therapies for malignant lymphoma based on molecular heterogeneity.

INTRODUCTION: Owing to tremendous advances in the understanding of mechanisms involved in the pathogenesis of malignant tumors an emerging field of novel targeted drugs has evolved within the last decade. This is of particular interest also for malignant lymphomas, constituting a heterogeneous tumor category with substantial variation in clinical outcome, ranging from indolent forms that do not require treatment over years to aggressive cases for which an immediate treatment is mandatory. The elucidation of different molecular strategies adopted by malignant cells has led to a profound profiling of tumor-specific features and consequently resulted in the development of new targeted therapies. Areas covered: A review of currently tested tailored approaches, in particular in B-cell lymphomas (B-NHL), ranging from monoclonal antibodies to inhibition of intrinsic and extrinsic effector molecules. These approaches are currently tested in several subtypes of B-NHL both in preclinical studies and in clinical trials and are summarized within this review. Expert commentary: Considering how quickly basic scientific discoveries could meanwhile be transferred to clinical trials and approvals, future perspectives for novel tailored therapeutic strategies are promising.