Transcriptomic rationale for the synergy observed with dasatinib + bortezomib + dexamethasone in multiple myeloma

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.

Modulation of natural killer cell effector functions through lenalidomide/dasatinib and their combined effects against multiple myeloma cells

The multikinase inhibitor dasatinib blocks the constitutive activation of oncogenic Src kinases in multiple myeloma (MM) cells and potentially enhances natural killer (NK) cell activity. Therefore, we tested combination effects of dasatinib and lenalidomide regarding MM cell viability and NK cell effector functions. The drug combination mostly had little influence on the viability of MM cell lines, and produced mixed results on primary MM cells. Prolonged lenalidomide treatment enhanced NK cell effector functions, and dasatinib addition at late stages of NK cell expansion increased levels of CD107a/b and interferon-γ (IFNγ), but not of tumor necrosis factor-α (TNFα). Additive effects were observed for the enhancement of cytokine production and degranulation, but only lenalidomide increased NK cell cytotoxicity against MM cells. This effect correlated with increased TNF-related apoptosis-inducing ligand (TRAIL) expression and was attenuated by dasatinib, or suppressors of TRAIL or TNFα. Our data thus indicate a functional role for the TRAIL/TRAIL-R system in lenalidomide-mediated NK-cell activity against MM cells, but also show that dasatinib is unsuitable to support or boost this effect.

Clinical utility and implementation of gene-expression profiling in myeloma: current status and challenges

SUMMARY Multiple myeloma, a neoplasm of terminally differentiated plasma cell, is the second most frequent hematological malignancy after non-Hodgkin’s lymphoma. Gene-expression profiling is a powerful and sensitive tool that can detect global transcriptional changes in cells. This technology has been applied in myeloma studies in the last decade in diverse areas such as understanding molecular pathogenesis, role of microenvironment, molecular heterogeneity, prognosis prediction and identification of novel therapeutic targets. In this review, we will briefly retrace the achievements and consider the future perspectives of gene-expression profiling in multiple myeloma research.

Disrupting the networks of cancer

Ecosystems are interactive systems involving communities of species and their abiotic environment. Tumors are ecosystems in which cancer cells act as invasive species interacting with native host cell species in an established microenvironment within the larger host biosphere. At its heart, to study ecology is to study interconnectedness. In ecologic science, an ecologic network is a representation of the biotic interactions in an ecosystem in which species (nodes) are connected by pairwise interactions (links). Ecologic networks and signaling network models have been used to describe and compare the structures of ecosystems. It has been shown that disruption of ecologic networks through the loss of species or disruption of interactions between them can lead to the destruction of the ecosystem. Often, the destruction of a single node or link is not enough to disrupt the entire ecosystem. The more complex the network and its interactions, the more difficult it is to cause the extinction of a species, especially without leveraging other aspects of the ecosystem. Similarly, successful treatment of cancer with a single agent is rarely enough to cure a patient without strategically modifying the support systems conducive to survival of cancer. Cancer cells and the ecologic systems they reside in can be viewed as a series of nested networks. The most effective new paradigms for treatment will be developed through application of scaled network disruption.