Combination of rituximab and mammalian target of rapamycin inhibitor everolimus (RAD001) in diffuse large B-cell lymphoma

Potential Pathogenic Impact of Cow’s Milk Consumption and Bovine Milk-Derived Exosomal MicroRNAs in Diffuse Large B-Cell Lymphoma

Epidemiological evidence supports an association between cow’s milk consumption and the risk of diffuse large B-cell lymphoma (DLBCL), the most common non-Hodgkin lymphoma worldwide. This narrative review intends to elucidate the potential impact of milk-related agents, predominantly milk-derived exosomes (MDEs) and their microRNAs (miRs) in lymphomagenesis. Upregulation of PI3K-AKT-mTORC1 signaling is a common feature of DLBCL. Increased expression of B cell lymphoma 6 (BCL6) and suppression of B lymphocyte-induced maturation protein 1 (BLIMP1)/PR domain-containing protein 1 (PRDM1) are crucial pathological deviations in DLBCL. Translational evidence indicates that during the breastfeeding period, human MDE miRs support B cell proliferation via epigenetic upregulation of BCL6 (via miR-148a-3p-mediated suppression of DNA methyltransferase 1 (DNMT1) and miR-155-5p/miR-29b-5p-mediated suppression of activation-induced cytidine deaminase (AICDA) and suppression of BLIMP1 (via MDE let-7-5p/miR-125b-5p-targeting of PRDM1). After weaning with the physiological termination of MDE miR signaling, the infant’s BCL6 expression and B cell proliferation declines, whereas BLIMP1-mediated B cell maturation for adequate own antibody production rises. Because human and bovine MDE miRs share identical nucleotide sequences, the consumption of pasteurized cow’s milk in adults with the continued transfer of bioactive bovine MDE miRs may de-differentiate B cells back to the neonatal “proliferation-dominated” B cell phenotype maintaining an increased BLC6/BLIMP1 ratio. Persistent milk-induced epigenetic dysregulation of BCL6 and BLIMP1 expression may thus represent a novel driving mechanism in B cell lymphomagenesis. Bovine MDEs and their miR cargo have to be considered potential pathogens that should be removed from the human food chain.

Immune targeted therapy for diffuse large B cell lymphoma

Diffuse large B-cell lymphoma (DLBCL), the most common subtype of non-Hodgkin lymphoma, is highly heterogeneous and invasive. Although the majority of DLBCL patients show a good response to rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone treatment, approximately one-third of patients still have a poor prognosis. Many immune-targeted drugs, such as bispecific T-cell engagers and CAR T-cell therapy, have been proven effective for refractory and relapsed patients. This article reviews the progress of immune targeted therapy for DLBCL.

Potential of the tumor‑derived extracellular vesicles carrying the miR‑125b‑5p target TNFAIP3 in reducing the sensitivity of diffuse large B cell lymphoma to rituximab

Diffuse large B-cell lymphoma (DLBCL) is the most common and aggressive form of non-Hodgkin's lymphoma. Extracellular vesicles (EVs) derived from cancer cells are known to modify the tumor microenvironment. The aim of the present study was to investigate the role of miR-125b-3p carried by EVs in DLBCL in vitro and in vivo. TNFAIP3 expression in patient lesions was measured and the upstream miR that regulates TNFAIP3 was predicted using the starBase database. EVs were isolated from DLBCL cells and identified. DLBCL cells were transfected with pcDNA to overexpress TNFAIP3 or inhibit miR-125b-5p expression, incubated with EVs, and treated with rituximab to compare cell growth and TNFAIP3/CD20 expression. DLBCL model mice were administered EVs, conditioned medium, and rituximab to observe changes in tumor size, volume, and weight. TNFAIP3 was downregulated in patients with DLBCL and its levels further decreased in patients with drug-resistant DLBCL. Overexpression of TNFAIP3 in DLBCL cells enhanced the inhibitory effect of rituximab and increased CD20 expression. miR-125b-5p targeted TNFAIP3. Inhibition of miR-125b-5p enhanced the inhibitory effect of rituximab in DLBCL cells. The EV-carried miR-125b-5p reduced the sensitivity of DLBCL cells to rituximab, which was averted by overexpression of TNFAIP3. EVs reduced the sensitivity of DLBCL model mice to rituximab via the miR-125b-5p/TNFAIP3 axis. The study findings indicate that the tumor-derived EVs carrying miR-125b-5p can enter DLBCL cells and target TNFAIP3, thus reducing the sensitivity of DLBCL to rituximab, which may provide a novel therapeutic approach for DLBCL.

Overview of Targeted Drugs for Mature B-Cell Non-hodgkin Lymphomas

The improved knowledge of pathogenetic mechanisms underlying lymphomagenesis and the discovery of the critical role of tumor microenvironments have enabled the design of new drugs against cell targets and pathways. The Food and Drug Administration (FDA) has approved several monoclonal antibodies (mAbs) and small molecule inhibitors (SMIs) for targeted therapy in hematology. This review focuses on the efficacy results of the currently available targeted agents and recaps the main ongoing trials in the setting of mature B-Cell non-Hodgkin lymphomas. The objective is to summarize the different classes of novel agents approved for mature B-cell lymphomas, to describe in synoptic tables the results they achieved and, finally, to draw future scenarios as we glimpse through the ongoing clinical trials. Characteristics and therapeutic efficacy are summarized for the currently approved mAbs [i.e., anti-Cluster of differentiation (CD) mAbs, immune checkpoint inhibitors, chimeric antigen receptor (CAR) T-cell therapy, and bispecific antibodies] as well as for SMIs i.e., inhibitors of B-cell receptor signaling, proteasome, mTOR BCL-2 HDAC pathways. The biological disease profiling of B-cell lymphoma subtypes may foster the discovery of innovative drug strategies for improving survival outcome in lymphoid neoplasms, as well as the trade-offs between efficacy and toxicity. The hope for clinical advantages should carefully be coupled with mindful awareness of the potential pitfalls and the occurrence of uneven, sometimes severe, toxicities.

Metabolic Reprogramming of Non-Hodgkin's B-Cell Lymphomas and Potential Therapeutic Strategies

Metabolism is a wide and general term that refers to any intracellular pathways the cell utilizes in order to satisfy its energetic demand and to support cell viability and/or division. Along with phenotypic changes, all mammalian cells including immune cells modulate their metabolic program in order to reach their effector functions. Exacerbated metabolism and metabolic flexibility are also hallmarks of tumor initiation and of tumor cell progression in a complex tumor microenvironment. Metabolic reprogramming is mainly directed by the serine/threonine kinase mTOR (mammalian target of rapamycin). mTOR exists in two structurally and functionally distinct complexes, mTORC1 and mTORC2 that coordinate environmental signals and metabolic/anabolic pathways to provide macromolecules and energy needed for survival and growth. Activation of mTORC1 is required during development, differentiation and activation of immune cells. Aberrant and persistent activation of mTORC1 is often observed in malignant B cells such as Non-Hodgkin's (NH) B-cell lymphomas. Here, we review recent insights on cell metabolism and on basic mechanisms of mTORC1 regulation and metabolic functions. We highlight the distinct mechanisms driving mTORC1 activation in the three most-common types of NH B-cell lymphomas (Diffuse Large B Cell Lymphomas, Follicular Lymphomas, and Mantle Cell Lymphomas), for which the first generation of mTORC1 inhibitors (rapalogs) have been extensively evaluated in preclinical and clinical settings. Finally, we discuss the reasons for limited clinical success of this therapy and focus on potential therapeutic strategies targeting metabolic pathways, upstream and downstream of mTORC1, that can be combined to rapalogs in order to improve patient's outcome.

Everolimus

Everolimus (RAD001) is an oral protein kinase inhibitor of the mTOR (mammalian target of rapamycin) serine/threonine kinase signal transduction pathway. The mTOR pathway regulates cell growth, proliferation and survival, and is frequently deregulated in cancer.The EMA has approved Everolimus as Afinitor^® for the treatment of hormone receptor-positive, HER2/neu-negative advanced breast cancer, in combination with exemestane, in postmenopausal women without symptomatic visceral disease after recurrence or progression following a nonsteroidal aromatase inhibitor, for the treatment of unresectable or metastatic, well- or moderately differentiated neuroendocrine tumors of pancreatic origin in adults with progressive disease, and for the treatment of unresectable or metastatic, well-differentiated (Grade 1 or Grade 2) nonfunctional neuroendocrine tumors of gastrointestinal or lung origin in adults with progressive disease, and for the treatment of patients with advanced renal cell carcinoma, whose disease has progressed on or after treatment with VEGF-targeted therapy And as Votubia^® for the treatment of adult patients with renal angiomyolipoma associated with tuberous sclerosis complex (TSC), who are at risk of complications (based on factors such as tumor size or presence of aneurysm, or presence of multiple or bilateral tumors) but who do not require immediate surgery, and for the treatment of patients with subependymal giant cell astrocytoma (SEGA) associated with TSC who require therapeutic intervention but are not amenable to surgery, and as an add-on treatment in patients from 2 years of age with seizures related to TSC that have not responded to other treatments ( https://www.novartis.com/news/media-releases/novartis-drug-votubiar-receives-eu-approval-treat-refractory-partial-onset ). The FDA has approved Everolimus as Afinitor^® for the treatment of postmenopausal women with advanced hormone receptor-positive, HER2-negative breast cancer in combination with exemestane, after the failure of treatment with letrozole or anastrozole, for the treatment of adult patients with progressive neuroendocrine tumors of pancreatic origin (PNET) with unresectable, locally advanced or metastatic disease, for the treatment of adult patients with advanced RCC after failure of treatment with sunitinib or sorafenib, for the treatment of adult patients with renal angiomyolipoma and tuberous sclerosis complex (TSC), not requiring immediate surgery. for the treatment of adult and pediatric patients, 3 years of age or older, with SEGA associated with TSC who require therapeutic intervention but are not candidates for curative surgical resection. Everolimus shows promising clinical activity in additional indications. Multiple Phase II and Phase III trials of everolimus alone or in combination and will help to further elucidate the role of mTOR in oncology. For a review on everolimus as immunosuppressant, please consult other sources.

Crizotinib in Combination with Everolimus Synergistically Inhibits Proliferation of Anaplastic Lymphoma Kinase‒Positive Anaplastic Large Cell Lymphoma

PURPOSE

Anaplastic large cell lymphoma (ALCL) is a rare aggresive non-Hodgkin lymphoma, of which over 50% of cases have an aberrant nucleophosmin (NPM)‒anaplastic lymphoma kinase (ALK) fusion protein. Both mechanistic target of rapamycin (mTOR) inhibitor everolimus and ALK inhibitor crizotinib have shown promising antitumor activity in ALK-positive cancer cell lines. However, their combined effect has not yet been investigated.

MATERIALS AND METHODS

We evaluated the anti-proliferative effects of everolimus and/or crizotinib in ALK-positive ALCL cell lines, Karpas 299 and SU-DHL-1, and lung adenocarcinoma cell line, NCI-H2228.

RESULTS

We found that individually, both everolimus and crizotinib potently inhibited cell growth in a dose-dependent manner in both Karpas 299 and SU-DHL-1 cells. A combination of these agents synergistically inhibited proliferation in the two cell lines. Crizotinib down-regulated aberrant AKT and ERK phosphorylation induced by everolimus. Combination treatment also significantly increased G0/G1 cell-cycle arrest, DNA damage, and apoptosis compared with everolimus or crizotinib alone in ALK-positive ALCL cells. In the Karpas 299 xenograft model, the combination treatment exerted a stronger antitumor effect than monotherapies, without significant change in body weight. The synergistic effect of everolimus and crizotinib was also reproduced in the ALK-positive lung adenocarcinoma cell line NCI-H2228. The combination treatment abrogated phosphoinositide 3-kinase/AKT and mTOR signaling pathways with little effect on the Ras/ERK pathway in NCI-H2228 cells.

CONCLUSION

Crizotinib combinedwith everolimus synergistically inhibits proliferation of ALK-positive ALCL cells. Our results suggest that this novel combination is worthy of further clinical development in patients with ALK-positive ALCL.

Differential regulation of mTOR signaling determines sensitivity to AKT inhibition in diffuse large B cell lymphoma

Agents that target components of the PI3K/AKT/mTOR pathway are under investigation for the treatment of diffuse large B cell lymphoma (DLBCL). Given the highly heterogeneous nature of DLBCL, it is not clear whether all subtypes of DLBCL will be susceptible to PI3K pathway inhibition, or which kinase within this pathway is the most favorable target. Pharmacological profiling of a panel of DLBCL cell lines revealed a subset of DLBCL that was resistant to AKT inhibition. Strikingly, sensitivity to AKT inhibitors correlated with the ability of these inhibitors to block phosphorylation of S6K1 and ribosomal protein S6. Cell lines resistant to AKT inhibition activated S6K1 independent of AKT either through upregulation of PIM2 or through activation by B cell receptor (BCR) signaling components. Finally, combined inhibition of AKT and BTK, PIM2, or S6K1 proved to be an effective strategy to overcome resistance to AKT inhibition in DLBCL.

Regulation of Bim in Health and Disease

The BH3-only Bim protein is a major determinant for initiating the intrinsic apoptotic pathway under both physiological and pathophysiological conditions. Tight regulation of its expression and activity at the transcriptional, translational and post-translational levels together with the induction of alternatively spliced isoforms with different pro-apoptotic potential, ensure timely activation of Bim. Under physiological conditions, Bim is essential for shaping immune responses where its absence promotes autoimmunity, while too early Bim induction eliminates cytotoxic T cells prematurely, resulting in chronic inflammation and tumor progression. Enhanced Bim induction in neurons causes neurodegenerative disorders including Alzheimer's, Parkinson's and Huntington's diseases. Moreover, type I diabetes is promoted by genetically predisposed elevation of Bim in β-cells. On the contrary, cancer cells have developed mechanisms that suppress Bim expression necessary for tumor progression and metastasis. This review focuses on the intricate network regulating Bim activity and its involvement in physiological and pathophysiological processes.

Emerging drugs for diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most frequent non-Hodgkin lymphoma in western countries. Despite the addition of rituximab to chemotherapy, the prognosis is still poor and almost one-third of patients fail or relapse after first-line treatment. Gene expression profiling has identified three main signatures related to subgroups with different biological characteristics and responses to treatment. Novel agents targeting the oncogenic drivers of these subsets are currently under investigation with the aim of providing a tailored approach and avoiding unnecessary toxicity. Herein, we review the emerging therapies for DLBCL with a focus on preclinical and early clinical trials as well as future directions.

Everolimus in diffuse large B-cell lymphomas

ABSTRACT 

Satisfactory treatment of relapsed/refractory diffuse large B-cell lymphoma (DLBCL) is not currently available and novel therapies are needed. mTOR is an intracellular kinase that is part of an aberrantly activated pathway in DLBCL. Preclinical studies in DLBCL cell lines demonstrated that everolimus, an oral selective mTOR inhibitor, induces cell cycle arrest and is synergistic with rituximab. Phase I studies indicated 10 mg daily to be the best dosing of everolimus in DLBCL. A large Phase II study in relapsed/refractory DLBCL confirmed the substantial activity (overall response rate: 30%) and good tolerability of everolimus in DLBCL, with thrombocytopenia being the main toxicity. The combination of everolimus and rituximab showed encouraging results (objective response rate: 38%; complete response: 13%), without increasing toxicity. Combination studies of everolimus with novel agents or with immunochemotherapy are underway.