Targeting RPL39 and MLF2 reduces tumor initiation and metastasis in breast cancer by inhibiting nitric oxide synthase signaling

We previously described a gene signature for breast cancer stem cells (BCSCs) derived from patient biopsies. Selective shRNA knockdown identified ribosomal protein L39 (RPL39) and myeloid leukemia factor 2 (MLF2) as the top candidates that affect BCSC self-renewal. Knockdown of RPL39 and MLF2 by specific siRNA nanoparticles in patient-derived and human cancer xenografts reduced tumor volume and lung metastases with a concomitant decrease in BCSCs. RNA deep sequencing identified damaging mutations in both genes. These mutations were confirmed in patient lung metastases (n = 53) and were statistically associated with shorter median time to pulmonary metastasis. Both genes affect the nitric oxide synthase pathway and are altered by hypoxia. These findings support that extensive tumor heterogeneity exists within primary cancers; distinct subpopulations associated with stem-like properties have increased metastatic potential.Large-scale sequencing analyses of solid cancers have identified extensive tumor heterogeneity within individual primary cancers (1). Recent studies indicate that such tumoral heterogeneity is associated with heterogeneous protein function, which fosters tumor adaptation, treatment resistance, and failure through Darwinian selection (2–4). Cancer stem cells are a subpopulation of cells within the primary tumor responsible for tumor initiation and metastases (5–9). Three groups have recently independently provided functional evidence for the presence of cancer stem cells by lineage-tracing experiments (10–12). These observations suggest that these subpopulations of cancer stem cells (CSCs) within the bulk primary tumor are resistant to conventional therapies through different adaptive mechanisms with the potential for self-renewal and metastases (7, 13, 14). However, few studies have determined the genetic profile of the cells that escape the primary cancer and evolve in distant metastatic sites (1). Additionally, no large-scale sequencing studies of metastases have been conducted because the majority of patients are treated with systemic therapies and not surgery.Tumor clonal heterogeneity within a primary tumor may in part be explained by hypoxic regions within the bulk tumor that have been correlated with invasiveness, therapeutic resistance, and metastasis (15–18). Cancer stem cells have been found to reside near hypoxic regions in some solid cancers (19–21). We have previously published a 477-gene tumorigenic signature by isolating breast cancer stem cells (BCSCs) derived from patient biopsies (22). Here, we have identified two previously unidentified cancer genes, ribosomal protein L39 (RPL39) and myeloid leukemia factor 2 (MLF2), by selective shRNA knockdown of genes from this tumorigenic signature, that impact breast cancer stem cell self-renewal and lung metastases. Analysis of 53 patient lung metastases confirmed damaging mutations in RPL39 and MLF2 in a significant number of samples, which conferred a gain-of-function phenotype. These mutations were statistically associated with shorter median time to distant relapse. We further describe a common mechanism of action through nitric oxide synthase signaling that is regulated by hypoxia.     

Preemptive CD20+ B cell depletion attenuates cardiac allograft vasculopathy in cyclosporine-treated monkeys

Chronic rejection currently limits the long-term efficacy of clinical transplantation. Although B cells have recently been shown to play a pivotal role in the induction of alloimmunity and are being targeted in other transplant contexts, the efficacy of preemptive B cell depletion to modulate alloimmunity or attenuate cardiac allograft vasculopathy (CAV) (classic chronic rejection lesions found in transplanted hearts) in a translational model has not previously been described. We report here that the CD20-specific antibody (αCD20) rituximab depleted CD20⁺ B cells in peripheral blood, secondary lymphoid organs, and the graft in cynomolgus monkey recipients of heterotopic cardiac allografts. Furthermore, CD20⁺ B cell depletion therapy combined with the calcineurin inhibitor cyclosporine A (CsA) prolonged median primary graft survival relative to treatment with αCD20 or CsA alone. In animals treated with both αCD20 and CsA that achieved efficient B cell depletion, alloantibody production was substantially inhibited and the CAV severity score was markedly reduced. We conclude therefore that efficient preemptive depletion of CD20⁺ B cells is effective in a preclinical model to modulate pathogenic alloimmunity and to attenuate chronic rejection when used in conjunction with a conventional clinical immunosuppressant. This study suggests that use of this treatment combination may improve the efficacy of transplantation in the clinic.     

Discriminated effects of thiolated chitosan-coated pMMA paclitaxel-loaded nanoparticles on different normal and cancer cell lines

The aim of the present work was to prepare and characterize poly(methyl methacrylate) nanoparticles coated by chitosan–glutathione conjugate so as to encapsulate insoluble anticancer drugs. Nanoparticles were synthesized through radical polymerization of methyl methacrylate initiated by cerium (IV) ammonium nitrate. Paclitaxel (PTX), a model anticancer drug, was encapsulated in nanoparticles with a maximal encapsulation efficiency of 98.27%. These nanoparticles showed sustained in vitro release of the incorporated PTX (75% of the loaded dose was released in 10 days). All nanoparticles had positive charge and were spherical, with a size range of about 130–250 nm. The PTX-loaded nanoparticles showed cytotoxicity for NIH 3T3 and T47D breast carcinoma cells, along with no cytotoxicity for two colon cell lines (HT29, Caco2).From the Clinical EditorThe aim of this work was to prepare and characterize poly(methyl methacrylate) nanoparticles coated by chitosan–glutathione conjugate in an effort to encapsulate Paclitaxel as a model of insoluble anticancer drugs. These nanoparticles showed sustained in vitro drug release.     

Apoptosis and dependence receptors: a molecular basis for cellular addiction

Classical signal transduction is initiated by ligand-receptor interactions. We have described an alternative form of signal transduction that is initiated by the withdrawal of ligands from specific receptors referred to as dependence receptors. This process is widespread, featuring in developmental cell death, carcinogenesis (especially metastasis), neurodegeneration, and possibly subapoptotic events such as neurite retraction and somal atrophy. Initial mechanistic studies of dependence receptors suggest that these receptors form complexes that include specific caspases. Complex formation appears to be a function of ligand-receptor interaction, and dependence receptors appear to exist in at least two conformational states. Complex formation in the absence of ligand leads to caspase activation by a mechanism that in at least some cases is dependent on caspase cleavage of the receptor itself, releasing proapoptotic peptides. Thus these receptors may serve in caspase amplification, and in so doing create cellular states of dependence on their respective ligands.     

Bilateral basal ganglia involvement in a patient with Griscelli syndrome.

We report a 6-year-old Iranian boy with silvery-gray hair, eyelashes and the eyebrows who was admitted because of seizures and subsequent stupor. He had previous history of acute hemiparesis at 1 year of age and hepatitis-like syndrome 3 months ago. Microscopic examination of the patient's hair shaft revealed different sized clumps of melanin seen in the center of the shafts. Bone marrow aspiration revealed erythroid hyperplasia and erythrophagocytic cells. Bilateral frontal cortical and subcortical high signal lesions, dirty white matter, high signal areas in the upper pons and in both caudates and lentiform nuclei in T2 WI were the brain MRI findings of the patient. He died in the accelerated phase of Griscelli Syndrome (GS) type 2. To our knowledge we report the first case of GS from Iran.     

Expression of CD40 induces neural apoptosis

The tumor necrosis factor receptor superfamily includes 12 members, some of which (e.g., tumor necrosis factor receptor I and FAS) induce cell death triggered by ligand binding. Another member of the superfamily, the neurotrophin receptor p75^NTR, induces neural apoptosis, with apoptosis being inhibited by binding of ligand to the receptor. As such, it is a candidate for the mediation of neurotrophin dependence. Here, we show that CD40, a superfamily member that is closely related to p75^NTR, also induces neural apoptosis, but apoptosis is inhibited by binding of the G28-5 monoclonal antibody to CD40. These results provide further support for a model in which some members of the tumor necrosis factor receptor superfamily induce apoptosis triggered by ligand binding, whereas other members may, at least under certain conditions, induce apoptosis in the absence of ligand binding, with apoptosis being inhibited by binding of ligand or monoclonal antibody. J. Neurosci. Res. 50:383–390, 1997. © 1997 Wiley-Liss, Inc.     

4D statistical shape modeling of the left ventricle in cardiac MR images

Purpose

Statistical shape models have shown improved reliability and consistency in cardiac image segmentation. They incorporate a sufficient amount of a priori knowledge from the training datasets and solve some major problems such as noise and image artifacts or partial volume effect. In this paper, we construct a 4D statistical model of the left ventricle using human cardiac short-axis MR images.

Methods

Kernel PCA is utilized to explore the nonlinear variation of a population. The distribution of the landmarks is divided into the inter- and intra-subject subspaces. We compare the result of Kernel PCA with linear PCA and ICA for each of these subspaces. The initial atlas in natural coordinate system is built for the end-diastolic frame. The landmarks extracted from it are propagated to all frames of all datasets. We apply the 4D KPCA-based ASM for segmentation of all phases of a cardiac cycle and compare it with the conventional ASM.

Results

The proposed statistical model is evaluated by calculating the compactness capacity, specificity and generalization ability measures. We investigate the behavior of the nonlinear model for different values of the kernel parameter. The results show that the model built by KPCA is less compact than PCA but more compact than ICA. Although for a constant number of modes the reconstruction error is a little higher for the KPCA-based statistical model, it produces a statistical model with substantially better specificity than PCA- and ICA-based models.

Conclusion

Quantitative analysis of the results demonstrates that our method improves the segmentation accuracy.     

Cocaine-induced renal infarction: report of a case and review of the literature

Background

Cocaine abuse has been known to have detrimental effects on the cardiovascular system. Its toxicity has been associated with myocardial ischemia, cerebrovascular accidents and mesenteric ischemia. The pathophysiology of cocaine-related renal injury is multifactorial and involves renal hemodynamic changes, alterations in glomerular matrix synthesis, degradation and oxidative stress, and possibly induction of renal atherogenesis. Renal infarction as a result of cocaine exposure, however, is rarely reported in the literature.

Case presentation

A 48 year-old male presented with a four-day history of severe right flank pain following cocaine use. On presentation, he was tachycardic, febrile and had severe right costovertebral angle tenderness. He had significant proteinuria, leukocytosis and elevated serum creatinine and lactate dehydrogenase. Radiographic imaging studies as well as other screening tests for thromboembolic events, hypercoagulability states, collagen vascular diseases and lipid disorders were suggestive of Cocaine-Induced Renal Infarction (CIRI) by exclusion.

Conclusion

In a patient with a history of cocaine abuse presenting with fevers and flank pain suggestive of urinary tract infection or nephrolithiasis, cocaine-induced renal infarction must be considered in the differential diagnosis. In this article, we discuss the prior reported cases of CIRI and thoroughly review the literature available on this disorder. This is important for several reasons. First, it will allow us to discuss and elaborate on the mechanism of renal injury caused by cocaine. In addition, this review will demonstrate the importance of considering the diagnosis of CIRI in a patient with documented cocaine use and an atypical presentation of acute renal injury. Finally, we will emphasize the need for a consensus on optimal treatment of this disease, for which therapy is not yet standardized.     

Outcomes of multiple myeloma patients receiving bortezomib,lenalidomide, and carfilzomib

New classes of drugs including the proteasome inhibitors (PI) bortezomib and, more recently, carfilzomib and the immunomodulatory agent lenalidomide have shown improved outcomes for multiple myeloma (MM) patients during the past decade. However, most of the studies reporting outcomes for patients receiving these drugs have relied on older data sets derived from large institutions that included patients not receiving their treatment at those facilities and represented only those eligible for clinical trials or were from sites where treatment options were limited. We have analyzed data from 258 MM patients who have received treatment with at least one of three agents: bortezomib, carfilzomib, and lenalidomide in a single clinic specializing in MM with respect to their responses and other outcomes to treatment regimens including these agents. Response rates were similar between these three drugs when used for the first time and again during subsequent treatment regimens. As expected, the clinical benefit rates (CBRs) were better for patients receiving their first treatment when compared to their use in subsequent treatment regimens. The CBRs were similar during their 2nd, 3rd, and 4th treatments containing these agents. Many patients refractory to these agents showed responses to regimens containing these same drugs when used in different combinations. In addition, patients refractory to one PI often responded to the other PI. The results of this study demonstrate that novel agents can be used repeatedly in novel combinations with significant clinical benefit for patients with MM.