Nelfinavir and lenalidomide/dexamethasone in patients with lenalidomide-refractory multiple myeloma. A phase I/II Trial (SAKK 39/10).

The antiretroviral agent nelfinavir has antimyeloma activity and can overcome resistance to bortezomib. Our phase I/II trial investigated whether adding nelfinavir to lenalidomide-dexamethasone can overcome lenalidomide resistance in lenalidomide-refractory multiple myeloma (MM). Twenty-nine patients were included (high-risk cytogenetic aberrations 31%; ≥2 prior therapy lines 93%; lenalidomide-bortezomib double-refractory 34%). Twenty-four patients (83%) had prior bortezomib and 10 (34%) were lenalidomide-bortezomib double-refractory. They received four cycles of nelfinavir 2500 mg/day with standard-dose lenalidomide (25 mg days 1-21) and dexamethasone (40/20 mg days 1, 8, 15, 22). Minor response or better was achieved in 16 patients (55%; 95% CI 36-74%), including 40% of those who were lenalidomide-bortezomib double-refractory, and partial response or better in nine patients (31%; 95% CI 15-51%). Median progression-free survival was 3.4 (95% CI 2.0-4.9) months and median overall survival 21.6 (13.0-50.1) months. Lenalidomide-related pneumonitis, pneumonia, and neutropenic fever occurred, but there were no unexpected adverse events. Peripheral blood mononuclear cells showed a 45% (95% CI 40-51%) reduction in total proteasome activity from baseline and significant induction of unfolded protein response and autophagy. Thus, nelfinavir-lenalidomide-dexamethasone is an active oral combination in lenalidomide-refractory MM.

Carfilzomib resistance due to ABCB1/MDR1 overexpression is overcome by nelfinavir and lopinavir in multiple myeloma.

Proteasome inhibitor (PI) carfilzomib (CFZ) has activity superior to bortezomib (BTZ) and is increasingly incorporated in multiple myeloma (MM) frontline therapy and relapsed settings. Most MM patients ultimately experience PI-refractory disease, an unmet medical need with poorly understood biology and dismal outcome. Pharmacologic targeting of ABCB1 improved patient outcomes, including MM, but suffered from adverse drug effects and insufficient plasma concentrations. Proteomics analysis identified ABCB1 overexpression as the most significant change in CFZ-resistant MM cells. We addressed the functional role of ABCB1 overexpression in MM and observed significantly upregulated ABCB1 in peripheral blood malignant plasma cells (PCs) vs untreated patients' bone marrow PC. ABCB1 overexpression reduces the proteasome-inhibiting activity of CFZ due to drug efflux, in contrast to BTZ. Likewise, the cytotoxicity of established anti-MM drugs was significantly reduced in ABCB1-expressing MM cells. In search for potential drugs targeting ABCB1 in clinical trials, we identified the HIV protease inhibitors nelfinavir (NFV) and lopinavir (LPV) as potent functional modulators of ABCB1-mediated drug export, most likely via modulation of mitochondria permeability transition pore. NFV and LPV restored CFZ activity at therapeutically relevant drug levels and thus represent ready-to-use drugs to be tested in clinical trials to target ABCB1 and to re-sensitize PC to established myeloma drugs, in particular CFZ.

Proteasome inhibitor-adapted myeloma cells are largely independent from proteasome activity and show complex proteomic changes, in particular in redox and energy metabolism.

Adaptive resistance of myeloma to proteasome inhibition represents a clinical challenge, whose biology is poorly understood. Proteasome mutations were implicated as underlying mechanism, while an alternative hypothesis based on low activation status of the unfolded protein response was recently suggested (IRE1/XBP1-low model). We generated bortezomib- and carfilzomib-adapted, highly resistant multiple myeloma cell clones (AMO-BTZ, AMO-CFZ), which we analyzed in a combined quantitative and functional proteomic approach. We demonstrate that proteasome inhibitor-adapted myeloma cells tolerate subtotal proteasome inhibition, irrespective of a proteasome mutation, and uniformly show an 'IRE1/XBP1-low' signature. Adaptation of myeloma cells to proteasome inhibitors involved quantitative changes in >600 protein species with similar patterns in AMO-BTZ and AMO-CFZ cells: proteins involved in metabolic regulation, redox homeostasis, and protein folding and destruction were upregulated, while apoptosis and transcription/translation were downregulated. The quantitatively most upregulated protein in AMO-CFZ cells was the multidrug resistance protein (MDR1) protein ABCB1, and carfilzomib resistance could be overcome by MDR1 inhibition. We propose a model where proteasome inhibitor-adapted myeloma cells tolerate subtotal proteasome inhibition owing to metabolic adaptations that favor the generation of reducing equivalents, such as NADPH, which is supported by oxidative glycolysis. Proteasome inhibitor resistance may thus be targeted by manipulating the energy and redox metabolism.

[Potential of Cell-free Circulating DNA in Diagnosis of Cancer]. / Potenciál volné cirkulující DNA v diagnostice nádorových onemocnení.

Circulating cell-free DNA (cf-DNA) is characterized as extracellular DNA that may be present in the blood of healthy individuals in low concentrations. Cf-DNA is released by apoptosis or necrosis into the bloodstream. Increased levels are found in pathological conditions, such as inflammation, autoimmune diseases, or stress. Significant increase of cf-DNA is particularly evident in patients with malignancies, especially in the advanced stages of the disease. In this case, the tumor specific cf-DNA is released by necrosis from the cells of primary tumor and metastases. Recently, many studies concentrate on the so-called 'liquid biopsies' that allow detection of circulating tumor cells and circulating nucleic acids from peripheral blood for tumor diagnostics. Quantitative methods and detection of genetic and epigenetic alternations of cf-DNA in patients with different malignancies have potential applications in molecular diagnosis, prognosis, monitoring of disease progression and response to treatment. This review focuses on potential utility of cf-DNA as a blood biomarker in selected solid tumors and hematologic malignancies.

[Cereblon -  a new target of therapy in the treatment of multiple myeloma]. / Cereblon -  nový terapeutický ciel v liecbe mnohopocetného myelómu.

Treatment of multiple myeloma (MM), currently an incurable disease, aims to achieve complete remission. Immunomodulatory drugs (IMiDs), represented by thalidomide, are one class of very effective drugs. However, the mechanism of IMiDs action is not yet completely understood. Recent research suggests that cereblon (CRBN) plays an important role in mediating anti-tumor effects of IMiDs; therefore, our review focuses on this protein. CRBN is a substrate receptor of Cul4- E3 ubiquitin ligase complex, and thus recognizes proteins destined for degradation. Bind-ing of CRBN and IMiDs inhibits function of the entire ubiquitin proteasome complex which partly explains their anti-tumor effects. In addition, a correlation between CRBN gene expression and effectiveness of treatment in MM patients treated with IMiDs was confirmed. These findings suggest that CRBN expression could possibly serve as a bio-marker to predict response to IMiD in MM patients.

Primary cilia are required for cerebellar development and Shh-dependent expansion of progenitor pool.

Cerebellar granule cell precursors (GCPs), which give rise to the most abundant neuronal type in the mammalian brain, arise from a restricted pool of primary progenitors in the rhombic lip (RL). Sonic hedgehog (Shh) secreted by developing Purkinje cells is essential for the expansion of GCPs and for cerebellar morphogenesis. Recent studies have shown that the primary cilium concentrates components of Shh signaling and that this structure is required for Shh signaling. GCPs have a primary cilium on their surface [Del Cerro, M.P., Snider, R.S. (1972). Studies on the developing cerebellum. II. The ultrastructure of the external granular layer. J Comp Neurol 144, 131-64.]. Here, we show that 1) this cilium can be conditionally ablated by crossing Kif3a(fl/-) mice with hGFAP-Cre mice, 2) removal of Kif3a from GCPs disrupts cerebellar development, and 3) these defects are due to a drastic reduction in Shh-dependent expansion of GCPs. A similar phenotype is observed when Smoothened (Smo), an essential transducer of Shh signaling, is removed from the same population of GCPs. Interestingly, Kif3a-Smo double conditional mutants show that Kif3a is epistatic to Smo. This work shows that Kif3a is essential for Shh-dependent expansion of cerebellar progenitors. Dysfunctional cilia are associated with diverse human disorders including Bardet-Biedl and Joubert syndromes. Cerebellar abnormalities observed in these patients could be explained by defects in Shh-induced GCP expansion.

[Stem cell biology and therapeutic hopes: forbidden game?]. / Biologie des cellules souches et perspectives thérapeutiques: enjeux interdits?

Stem cell biology is one of the most exciting subjects in life science nowadays. The major point in stem cell biology is the extraordinary capacity of these cells to self-renew and to give rise to different cell types. Nevertheless, major issues remain to be cleared and very few diseases can actually be cured based on stem cell therapy. Adult stem cells remain difficult to locate, isolate and amplify in a homogeneous fashion and, thus, limit their therapeutic application in clinical trial. Embryonic stem cells could represent a new hope in stem cell therapy but in addition to the scientific difficulties, over ethical and judiciary issues should be addressed. In order to cure routinely patients, controlled conditions for stem cell isolation, amplification, differentiation, and administration must be defined and effective tissue integration have to be established. In this review we will discuss these different aspects of stem cell biology.

Evaluation of a new integrated discharge prescription form.

OBJECTIVE: To determine whether a new discharge prescription form which integrates admission medications, in-hospital changes, and discharge medications could enhance the accuracy of information in patient profiles in community pharmacies after hospital discharge. DESIGN: Nonrandomized, prospective, multi-site study. SETTINGS: Internal medicine wards of the three teaching hospitals (1200 beds) of the Centre Hospitalier de l'Université de Montréal. SUBJECTS: Patients admitted to the internal medicine wards between January 4 and 31, 1999, at St.-Luc and Notre-Dame Hospitals formed the control group and received a usual discharge form (UD). Those admitted between February 1 and 28,1999, received the new discharge prescription form (DPF) capturing the list of admission medications and revisions during hospitalization; they served as the experimental group. METHODS: Patient profiles were reviewed to calculate conformity rates of community pharmacy patient profiles after discharge and the rate of overall conformity for each group in the study. Each drug in the patient profile was assessed according to six criteria. Healthcare providers' satisfaction with the DPF was assessed via a written questionnaire. RESULTS: Eighty-nine patients and 669 discharge medications were studied. The patient profiles had a higher conformity rate in the DPF group than in the UD group (82% vs. 40%; p < 0.001); improvement could be attributed to higher conformity rates, particularly for two criteria (medications stopped in hospital and dose changes in hospital). CONCLUSIONS: Integration of admission medications, in-hospital changes, and discharge medications on a single form increases the conformity rates of community pharmacy patient profiles after hospitalization. This tool is well accepted by both pharmacists and physicians and may lead to a major decrease in drug-related problems.

Neuroprotection of the developing brain by systemic administration of vasoactive intestinal peptide derivatives.

Periventricular leukomalacia (PVL), a necrotic and often cystic lesion of the cerebral white matter occurring in very premature babies, is the leading cause of cerebral palsy in this population. Increased glutamate release and the excitotoxic cascade thus triggered may be critical factors in the development of PVL. The glutamatergic analog ibotenate injected intracerebrally into newborn mice produces white matter cysts that mimic human PVL. Concomitant injection of vasoactive intestinal peptide (VIP), a trophic factor, protects the white matter against excitotoxic lesions. The goal of the present study was to assess the protective properties of systemically injected VIP analogs against ibotenate-induced excitotoxic white matter lesions in newborn mice. VIP analogs were selected on the basis of their low susceptibility to endopeptidases and their potential ability to cross biological membranes. RO-25-1553, a long-lasting cyclic VIP analog, and stearyl-norleucine-VIP, a fatty derivative of VIP, reduced ibotenate-induced white matter cysts by up to 87% and 84%, respectively, when injected i.p. immediately after ibotenate. By comparison, i.p. coadministration of VIP and ibotenate was not protective against the excitotoxic insult. Furthermore, RO-25-1553 and stearyl-norleucine-VIP still induced significant neuroprotection of the developing white matter when injected systemically 8 and 12 h, respectively, after ibotenate, establishing these peptides as therapeutic agents in this murine model. VIP analogs may have therapeutic potential in human premature babies at high risk for PVL.

Maternal protein restriction early in rat pregnancy alters brain development in the progeny.

We assessed the effects of a dietary protein restriction (5% vs. 20% casein in diet) initiated at conception and imposed during the first 2 weeks of rat gestation on postnatal brain development. At the end of the malnutrition period, protein-restricted animals exhibited significantly smaller fetal body weight and brain cortical thickness than controls. At birth and thereafter, body weight was normalized in the progeny. Similarly, brain weight and cytoarchitecture were normal in postnatal animals. In contrast, we observed, during the first 2 postnatal weeks, several abnormalities of brain development which affected all the studied areas for most of the studied parameters: (i) delayed astrocytogenesis as shown by a reduced GFAP staining; (ii) delayed production of hyaluronan in the extracellular matrix studied with binding of biotinylated hyaluronectin; (iii) abnormal neuronal differentiation as shown by reduced expression of MAP-5 and increased expression of MAP-1; (iv) abnormal synaptogenesis as shown by the increased expression of synaptophysin in the basal ganglia; (v) decreased programmed cell death. In adult prenatally protein-restricted animals, all the above parameters were normalized excepted MAP-1 labeling which remained high. In addition, we observed slight alterations of the ventilatory response to hypoxia in adult animals. The present study demonstrates that early protein malnutrition during embryonic development induces multiple, transient alterations of brain development. However, the almost complete normalization in adults of brain architecture and differentiation as well as our physiological data strongly suggest a remarkable plasticity of the developing brain following an early aggression.