Light chain deposition disease masquerading as smoking-associated nodular glomerulosclerosis with deposits identified by electron microscopy only.

Light chain deposition disease (LCDD) is a form of monoclonal gammopathy of renal significance. The diagnosis is based on the immunofluorescence (IF) findings of linear monoclonal light chain staining of basement membranes throughout the kidney, which appear as non-organized, granular punctate to powdery electron dense deposits by electron microscopy (EM). Although "LCDD by IF only" without EM deposits has been well-described, LCDD identified by EM with negative IF is very rare and hardly mentioned in the literature. Herein we describe a case of lambda-type LCDD that appeared negative by IF and showed light microscopic findings of nodular glomerulosclerosis, which was initially attributed to the patient's history of significant tobacco use and uncontrolled hypertension. However, EM later showed powdery electron dense material in focal glomerular and tubular basement membranes and mesangium. Subsequent bone marrow analysis revealed greater than 60% lambda-restricted plasma cells. We report this case to illustrate that within the differential diagnosis of nodular sclerosis, monoclonal immunoglobulin deposition disease (MIDD) should remain in the differential even if immunofluorescence appears negative as EM can prove to be crucial in identifying cases of MIDD.

Oncogenic Integration of Nucleotide Metabolism via Fatty Acid Synthase in Non-Hodgkin Lymphoma.

Metabolic dysfunctions enabling increased nucleotide biosynthesis are necessary for supporting malignant proliferation. Our investigations indicate that upregulation of fatty acid synthase (FASN) and de novo lipogenesis, commonly observed in many cancers, are associated with nucleotide metabolic dysfunction in lymphoma. The results from our experiments showed that ribonucleotide and deoxyribonucleotide pool depletion, suppression of global RNA/DNA synthesis, and cell cycle inhibition occurred in the presence of FASN inhibition. Subsequently, we observed that FASN inhibition caused metabolic blockade in the rate-limiting step of the oxidative branch of the pentose phosphate pathway (oxPPP) catalyzed by phosphogluconate dehydrogenase (PGDH). Furthermore, we determined that FASN inhibitor treatment resulted in NADPH accumulation and inhibition of PGDH enzyme activity. NADPH is a cofactor utilized by FASN, also a known allosteric inhibitor of PGDH. Through cell-free enzyme assays consisting of FASN and PGDH, we delineated that the PGDH-catalyzed ribulose-5-phosphate synthesis is enhanced in the presence of FASN and is suppressed by increasing concentrations of NADPH. Additionally, we observed that FASN and PGDH were colocalized in the cytosol. The results from these experiments led us to conclude that NADP-NADPH turnover and the reciprocal stimulation of FASN and PGDH catalysis are involved in promoting oxPPP and nucleotide biosynthesis in lymphoma. Finally, a transcriptomic analysis of non-Hodgkin's lymphoma (n = 624) revealed the increased expression of genes associated with metabolic functions interlinked with oxPPP, while the expression of genes participating in oxPPP remained unaltered. Together we conclude that FASN-PGDH enzymatic interactions are involved in enabling oxPPP and nucleotide metabolic dysfunction in lymphoma tumors.

Combinatorial ixazomib and belinostat therapy induces NFE2L2-dependent apoptosis in Hodgkin and T-cell lymphoma.

Ixazomib activity and transcriptomic analyses previously established in T cell (TCL) and Hodgkin (HL) lymphoma models predicted synergistic activity for histone deacetylase (HDAC) inhibitory combination. In this present study, we determined the mechanistic basis for ixazomib combination with the HDAC inhibitor, belinostat, in HL and TCL cells lines (ixazomib-sensitive/resistant clones) and primary tumour cells. In ixazomib-treated TCL and HL cells, transient inhibition followed by full recovery of proteasomal activity observed was accompanied by induction of proteasomal gene expression with NFE2L2 (also termed NRF2) as a prominent upstream regulator. Downregulation of both NFE2L2 and proteasomal gene expression (validated by quantitative real time polymerase chain reaction) occurred with belinostat treatment in Jurkat and L428 cells. In addition, CRISPR/Cas9 mediated knockdown of NFE2L2 in Jurkat cells resulted in a significant decrease in cell viability with ixazomib compared with untreated control cells. Using transcriptomic and proteasomal activity evaluation of ixazomib, belinostat, or ixazomib + belinostat treated cells, we observed that NFE2L2, proteasome gene expression and functional recovery were abrogated by ixazomib + belinostat combination, resulting in synergistic drug activity in ixazomib-sensitive and -resistant cell lines and primary cells. Altogether, these results suggest that the synergistic activity of ixazomib + belinostat is mediated via inhibition NFE2L2-dependent proteasomal recovery and extended proteasomal inhibition culminating in increased cell death.

A review of thrombotic microangiopathies in multiple myeloma.

Patients with multiple myeloma (MM) are susceptible to developing thrombotic microangiopathies (TMAs), an etiologically diverse group of syndromes which include atypical hemolytic uremic syndrome (aHUS) and thrombotic thrombocytopenic purpura (TTP). The TMAs are characterized by thrombocytopenia and microangiopathic hemolytic anemia (MAHA), and are associated with a high mortality risk and irreversible end-organ damage when treatment is delayed. In MM patients, TMAs may be triggered by specific chemotherapies, bone marrow transplantation (BMT), and progression of underlying disease. Because many characteristics of TMAs overlap with sequelae of MM and its treatments, diagnosis requires a high index of suspicion. Furthermore, our understanding of optimal treatments for these entities is rapidly evolving and clinical practice guidelines do not yet exist. Historically, consideration of a diagnosis of TMA has prompted initiation of therapeutic plasma exchange. In this review, we present an overview of the MM-related TMAs, an approach to workup and diagnosis, and argue for initial empiric MM-related TMA treatment with eculizumab rather than plasma exchange.

Second line treatment options for pancreatic cancer.

INTRODUCTION: Patients with advanced pancreatic cancer (APC) refractory to first-line therapy have a dismal prognosis and limited therapeutic options, with only one option consisting of nanoliposomal irinotecan in combination with fluorouracil and folinic acid which was approved by FDA based upon results of the phase III NAPOLI-1 study. Areas covered: We performed a literature search for relevant published clinical trials, abstracts of trials in progress and ongoing or planned trials for the second line treatment of APC using Pubmed.com, ClinicalTrials.gov and American Society of Clinical Oncology (ASCO) abstract search as sources. We present an in-depth analysis of the phase I-III clinical trials determining the role and efficacy of second-line treatment in patients with APC. We also describe ongoing studies and rationale for future investigation. Expert opinion: Despite advances in first-line therapy such as gemcitabine/nab-paclitaxel and FOLFIRINOX in APC, median overall survival remains less than 12 months, highlighting the need to develop second-line therapies. In order to establish much needed effective second-line treatment options, we need cooperative efforts among institutions and community practices in enrolling these refractory patients in clinical trials. It should be emphasized that in addition to chemotherapy options, all patients should have the opportunity to consult with nutritionist, social worker and palliative care health providers to assist with goals of care, symptom management and end of life discussions.

The safety and efficacy of Onivyde (irinotecan liposome injection) for the treatment of metastatic pancreatic cancer following gemcitabine-based therapy.

INTRODUCTION: Patients with advanced and metastatic pancreatic cancer refractory to gemcitabine based therapy have a dismal prognosis and limited therapeutic options. Recently, the FDA approved nanoliposomal irinotecan combined with fluorouracil/folinic acid for such patients based upon results of the NAPOLI-1 study which showed this regimen compared to fluorouracil/folinic acid significantly prolonged progression free survival (3.1 vs. 1.5 months) and overall survival (6.2 vs. 4.1 months). AREAS COVERED: The pharmacokinetic and pharmacogenetic characteristics of this novel formulation of irinotecan, its safety profile, and use in a clinical context for patients with pancreatic cancer are reviewed. Expert commentary: Nanoliposomal irinotecan, in combination with 5-FU/folinic acid, represents an important step forward in improving second line treatment options in patients with progression of metastatic pancreatic cancer. Furthermore, the novel drug formulation offers pharmacokinetic advantages which serve as a basis for further clinical testing in a various pancreatic cancer settings and other malignancies.

Mexiletine for refractory chronic daily headache: a report of nine cases.

OBJECTIVE: To describe the use of mexiletine in the treatment of chronic daily headache in a refractory headache population. BACKGROUND: Intravenous lidocaine is a novel treatment for chronic daily headache with medication overuse and SUNCT syndrome. Mexiletine is a similar but orally active anti-arrhythmic that has been demonstrated to be an effective analgesic in various types of neuropathic pain. We looked at mexiletine as a preventative treatment for headache in refractory patients. METHODS: We reviewed the medical records of all patients with an order for mexiletine. For each patient, we determined diagnosis, presence of medication overuse on initial evaluation, pain scores, and if the patient received intravenous lidocaine before starting the medication. We then contacted patients by phone to confirm their dose, to review side effects and current pain scores, and to obtain a global impression of effectiveness. RESULTS: We identified 9 patients with a chronic daily headache, including chronic migraine or new daily persistent headache, with significant clinical improvement while using mexiletine as a headache preventative. Each patient had failed to respond to multiple preventative and acute treatments. Seven of the 9 rated mexiletine "much more effective" and 2 "more effective" than previous preventative headache medications. The daily dose ranged from 600 mg/day to 1500 mg/day. Side effects were common and occurred in 7 patients. The majority of patients with an order for mexiletine did not respond to treatment or had intolerable side effects. DISCUSSION: The preliminary study suggests mexiletine is a useful preventative treatment for some patients with chronic daily headache, including refractory patients with medication overuse or those who have failed multiple preventatives in the past.