Inhibition of NF-κB DNA Binding Suppresses Myeloma Growth via Intracellular Redox and Tumor Microenvironment Modulation.

Multiple myeloma is a plasma cell malignancy that is still largely incurable, despite considerable progress in recent years. NF-κB is a well-established therapeutic target in multiple myeloma, but none of the currently available treatment options offer direct, specific pharmacologic targeting of NF-κB transcriptional activity. Thus, we designed a novel direct NF-κB inhibitor (IT848) as a drug candidate with strong potential for clinical translation and conducted comprehensive in vitro and in vivo mechanistic studies in multiple myeloma cell lines, primary multiple myeloma cells, xenograft models, and immunocompetent mouse models of multiple myeloma. Here, we show that IT848 inhibits NF-κB activity through inhibition of DNA binding of all five NF-κB subunits. IT848 treatment of multiple myeloma cell lines and patient samples inhibited proliferation and induced caspase-dependent and independent apoptosis. In addition to direct NF-κB inhibitory effects, IT848 treatment altered the redox homeostasis of multiple myeloma cells through depletion of the reduced glutathione pool, selectively inducing oxidative stress in multiple myeloma but not in healthy cells. Multiple myeloma xenograft studies confirmed the efficacy of IT848 as single agent and in combination with bortezomib. Furthermore, IT848 significantly improved survival when combined with programmed death protein 1 inhibition, and correlative immune studies revealed that this clinical benefit was associated with suppression of regulatory T-cell infiltration of the bone marrow microenvironment. In conclusion, IT848 is a potent direct NF-κB inhibitor and inducer of oxidative stress specifically in tumor cells, displaying significant activity against multiple myeloma cells in vitro and in vivo, both as monotherapy as well as in combination with bortezomib or immune checkpoint blockade.

Size Matters: Arginine-Derived Peptides Targeting the PSMA Receptor Can Efficiently Complex but Not Transfect siRNA.

Oligoarginine sequences conjugated to a short cancer-targeting peptide (CTP) selective for the prostate-specific membrane antigen (PSMA) receptor was developed for selective small interfering RNA (siRNA) delivery to a human metastatic/castration-resistant prostate cancer (PCa) cell line, which expresses PSMA on the surface. The PSMA-Rn (n = 6 and 9) peptides were synthesized by solid-phase peptide synthesis, characterized by liquid chromatography-mass spectrometry (LC-MS) and condensed with glucose-regulated protein (GRP)-silencing siRNAs. Native gels showed formation of stable CTP:siRNA ionic complexes. Furthermore, siRNA release was effected by heparin competition, supporting the peptides' capabilities to act as condensing and releasing agents. However, dynamic light scattering (DLS) and transmission electron microscopy (TEM) studies revealed large anionic complexes that were prone to aggregation and limited cell uptake for RNAi activity. Taken together, these data support the notion that the development of efficient peptide-based siRNA delivery systems is in part contingent on the formulation of discrete nanoparticles that can effectively condense and release siRNA in cells.

A systematic review on the influence of fear of falling on quality of life in older people: is there a role for falls?

Maintaining or improving quality of life (QoL) is a key outcome of clinical interventions in older people. Fear of falling (FoF) is associated with activity restriction as well as with poorer physical and cognitive functions and may be an important contributor to a diminished QoL. The objectives of this systematic review were to determine i) the effect of FoF on QoL in older people, ii) whether the association between these two constructs depends on the use of specific conceptualizations and measurement instruments, and iii) the role of fall events as mediating factor in this relationship. Four electronic databases (PubMed, EMBASE, CINAHL, and Cochrane Library) were searched from their inceptions to February 2018. Thirty mostly cross-sectional studies in nearly 30.000 people (weighted mean age 75.6 years (SD =6.1); 73% women) were included. FoF was associated with QoL in most studies, and this association appeared to be independent of the conceptualization of FoF. Moreover, this relationship was independent of falls people experienced which seemed to have a lower impact. FoF should be considered not only as by-product of falls and targeted interventions in parts different from those to reduce falls are likely required. Studies are needed showing that reducing FoF will lead to increased QoL.

GRP78 modulates cell adhesion markers in prostate Cancer and multiple myeloma cell lines.

BACKGROUND: Glucose regulated protein 78 (GRP78) is a resident chaperone of the endoplasmic reticulum and a master regulator of the unfolded protein response under physiological and pathological cell stress conditions. GRP78 is overexpressed in many cancers, regulating a variety of signaling pathways associated with tumor initiation, proliferation, adhesion and invasion which contributes to metastatic spread. GRP78 can also regulate cell survival and apoptotic pathways to alter responsiveness to anticancer drugs. Tumors that reside in or metastasize to the bone and bone marrow (BM) space can develop pro-survival signals through their direct adhesive interactions with stromal elements of this niche thereby resisting the cytotoxic effects of drug treatment. In this study, we report a direct correlation between GRP78 and the adhesion molecule N-cadherin (N-cad), known to play a critical role in the adhesive interactions of multiple myeloma and metastatic prostate cancer with the bone microenvironment. METHODS: N-cad expression levels (transcription and protein) were evaluated upon siRNA mediated silencing of GRP78 in the MM.1S multiple myeloma and the PC3 metastatic prostate cancer cell lines. Furthermore, we evaluated the effects of GRP78 knockdown (KD) on epithelial-mesenchymal (EMT) transition markers, morphological changes and adhesion of PC3 cells. RESULTS: GRP78 KD led to concomitant downregulation of N-cad in both tumors types. In PC3 cells, GRP78 KD significantly decreased E-cadherin (E-cad) expression likely associated with the induction in TGF-ß1 expression. Furthermore, GRP78 KD also triggered drastic changes in PC3 cells morphology and decreased their adhesion to osteoblasts (OSB) dependent, in part, to the reduced N-cad expression. CONCLUSION: This work implicates GRP78 as a modulator of cell adhesion markers in MM and PCa. Our results may have clinical implications underscoring GRP78 as a potential therapeutic target to reduce the adhesive nature of metastatic tumors to the bone niche.

Enhanced Cancer Theranostics with Self-Assembled, Multilabeled siRNAs.

The integration of therapy and diagnostics, termed "theranostics", has recently gained widespread utility in the development of new and improved therapeutics that effectively diagnose and treat diseases, such as cancer. In this study, the covalent attachment of multiple fluorescent labels (i.e., fluorescein isothiocyanate (FITC)) to a wide range of siRNAs, including those adopting linear, V- and Y-shape nanostructures, was successfully accomplished by solid-phase bioconjugation for monitoring cell uptake, co-localization, and biological activity in cell culture. The FITC-labeled higher-order V- and Y-shape siRNAs maintained the requisite hybrid stabilities and A-type helical structures for invoking RNAi activity. The FITC-siRNA hybrids with sense-strand modifiers enabled efficient mRNA knockdown (∼50-90%), which also translated to increased cell death (∼20-95%) in a bone metastatic prostate cancer cell line, over a 72 h incubation period. Significantly, the Y-shaped siRNA containing three FITC probes enhanced fluorescent signaling relative to the siRNA constructs containing single and double fluorophores while retaining potent knockdown and cell death effects post-transfection. Taken together, this data highlights the theranostic utility of the multilabeled FITC-siRNA constructs for potential cancer gene therapy applications.