Ex vivo drug response heterogeneity reveals personalized therapeutic strategies for patients with multiple myeloma.

Multiple myeloma (MM) is a plasma cell malignancy defined by complex genetics and extensive patient heterogeneity. Despite a growing arsenal of approved therapies, MM remains incurable and in need of guidelines to identify effective personalized treatments. Here, we survey the ex vivo drug and immunotherapy sensitivities across 101 bone marrow samples from 70 patients with MM using multiplexed immunofluorescence, automated microscopy and deep-learning-based single-cell phenotyping. Combined with sample-matched genetics, proteotyping and cytokine profiling, we map the molecular regulatory network of drug sensitivity, implicating the DNA repair pathway and EYA3 expression in proteasome inhibitor sensitivity and major histocompatibility complex class II expression in the response to elotuzumab. Globally, ex vivo drug sensitivity associated with bone marrow microenvironmental signatures reflecting treatment stage, clonality and inflammation. Furthermore, ex vivo drug sensitivity significantly stratified clinical treatment responses, including to immunotherapy. Taken together, our study provides molecular and actionable insights into diverse treatment strategies for patients with MM.

A novel dual-cytokine-antibody fusion protein for the treatment of CD38-positive malignancies.

A novel dual-cytokine-antibody fusion protein, consisting of an antibody directed against CD38 [a tumor-associated antigen mainly expressed on the surface of multiple myeloma (MM) cells], simultaneously fused to both tumor necrosis factor ligand superfamily member 10 (TRAIL) and interleukin-2 (IL2), was designed, expressed and purified to homogeneity. The novel fusion protein, termed IL2-αCD38-αCD38-scTRAIL, was able to selectively recognize its cognate antigen expressed on the surface of MM and lymphoma cell lines, as evidenced by flow cytometry analysis. Moreover, the targeted version of TRAIL was able to induce cancer cell death in vitro, both with MM cell lines and with fresh isolates from the bone marrow of MM patients. The experiments provide a rationale for possible future applications of IL2-αCD38-αCD38-scTRAIL for the treatment of patients with MM or other CD38-positive malignancies.

Postnatal dynamics of Zeb2 expression in rat brain: analysis of novel 3' UTR sequence reveals a miR-9 interacting site.

ZEB2 is a transcription factor with established roles in neurogenesis but no defined function in postnatal brain despite extensive neuronal expression in telencephalic structures. Multiple, incompletely annotated transcripts derive from the Zeb2 locus; the purpose of the present study was to structurally characterize rat brain Zeb2 transcripts with respect to 3' untranslated (UTR) sequence in order to understand Zeb2 transcript regulation including possible interactions with regulatory molecules such as neuronal miRNAs. We cloned a 5054-nucleotide Zeb2 3' UTR that is included in the most abundant Zeb2 transcript in neonatal rat brain. Unique features of the distal 3' UTR region included a number of brain-specific miRNA target sites; a highly conserved miR-9 target site at 3' UTR position 4097 was selected for functional verification in transfection experiments. Parallel analysis of Zeb2 transcript, ZEB2 protein and miR-9 levels across postnatal brain cortical development revealed a significant accumulation of ZEB2 protein levels only between postnatal days P2 and P5 that was associated with an acute loss of postnatal miR-9 expression in cortex. These studies demonstrate novel features of Zeb2 gene expression in postnatal rat brain and highlight the importance of full transcript annotation for identifying the complement of potential transcript-interacting regulators.