Reductive carboxylation supports redox homeostasis during anchorage-independent growth.

Cells receive growth and survival stimuli through their attachment to an extracellular matrix (ECM). Overcoming the addiction to ECM-induced signals is required for anchorage-independent growth, a property of most malignant cells. Detachment from ECM is associated with enhanced production of reactive oxygen species (ROS) owing to altered glucose metabolism. Here we identify an unconventional pathway that supports redox homeostasis and growth during adaptation to anchorage independence. We observed that detachment from monolayer culture and growth as anchorage-independent tumour spheroids was accompanied by changes in both glucose and glutamine metabolism. Specifically, oxidation of both nutrients was suppressed in spheroids, whereas reductive formation of citrate from glutamine was enhanced. Reductive glutamine metabolism was highly dependent on cytosolic isocitrate dehydrogenase-1 (IDH1), because the activity was suppressed in cells homozygous null for IDH1 or treated with an IDH1 inhibitor. This activity occurred in absence of hypoxia, a well-known inducer of reductive metabolism. Rather, IDH1 mitigated mitochondrial ROS in spheroids, and suppressing IDH1 reduced spheroid growth through a mechanism requiring mitochondrial ROS. Isotope tracing revealed that in spheroids, isocitrate/citrate produced reductively in the cytosol could enter the mitochondria and participate in oxidative metabolism, including oxidation by IDH2. This generates NADPH in the mitochondria, enabling cells to mitigate mitochondrial ROS and maximize growth. Neither IDH1 nor IDH2 was necessary for monolayer growth, but deleting either one enhanced mitochondrial ROS and reduced spheroid size, as did deletion of the mitochondrial citrate transporter protein. Together, the data indicate that adaptation to anchorage independence requires a fundamental change in citrate metabolism, initiated by IDH1-dependent reductive carboxylation and culminating in suppression of mitochondrial ROS.

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Effectiveness of Rituximab for the Treatment of Rheumatoid Arthritis in Patients with Prior Exposure to Anti-TNF: Results from the CORRONA Registry.

To characterize the real-world effectiveness of rituximab (RTX) in patients with rheumatoid arthritis.
Clinical effectiveness at 12 months was assessed in patients who were prescribed RTX based on the Clinical Disease Activity Index (CDAI). Change in CDAI was calculated (CDAI at 12 mos minus at initiation). Achievement of remission or low disease activity (LDA; CDAI ≤ 10) among those with moderate/high disease activity at the time of RTX initiation was compared based on prior anti-tumor necrosis factor agent (anti-TNF) use (1 vs ≥ 2) using logistic regression models.
Patients (n = 265) were followed for 12 months with a mean change in CDAI of -8.1 (95% CI -9.8 – -6.4). Of the 218 patients with moderate/high disease activity at baseline, patients with 1 prior anti-TNF (baseline CDAI 25.0) demonstrated a mean change in CDAI of -10.1 (95% CI -13.2 – -7.0); patients with ≥ 2 prior anti-TNF (baseline CDAI 30.0) demonstrated a mean change of -10.5 (95% CI -12.9 – -8.0). The unadjusted OR for achieving LDA/remission in patients with moderate/high disease activity at baseline exposed to ≥ 2 versus 1 prior anti-TNF was 0.40 (95% CI 0.22-0.73), which was robust to 4 different adjusted models (OR range 0.38-0.44).
A good clinical response was observed in all patients; however, patients previously treated with 1 anti-TNF, who had lower baseline CDAI and a greater opportunity for clinical improvement compared with patients previously treated with ≥ 2 anti-TNF, were more likely to achieve LDA/remission.

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The Clinical Use of Genomic Profiling to Distinguish Intrapulmonary Metastases From Synchronous Primaries in Non-Small-Cell Lung Cancer: A Mini-Review.

The ability to reliably distinguish synchronous primary non-small-cell lung cancer (NSCLC) from intrapulmonary metastatic spread affects staging and treatment decisions in resected NSCLC. Adjuvant therapy for early-stage NSCLC is complicated and recommendations are primarily based on older data from trials that used now-outdated staging systems. Patients found to have 2 tumors with similar morphology in the same lobe are currently staged as pathologic T3 (pT3) but such cases represent a minority of patients in adjuvant lung cancer trials. Potentially more precise than tumor morphology alone, comprehensive genomic profiling technologies have the power to discriminate whether tumors in the same lobe represent 2 separate primary lesions or localized spread of a single lesion. In addition to lineage insights, tumor profiling simultaneously provides information on actionable genomic alterations. In this review we discuss the data that support the ability of molecular technologies to distinguish synchronous primary tumors from intrapulmonary metastases and discuss the use of molecular assays as an adjunct to current staging systems. Two cases are presented to highlight the potential immediate clinical implications of comprehensive genomic profiling.
Copyright © 2015 Elsevier Inc. All rights reserved.

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BRAFV600E Mutations in High Grade Colorectal Neuroendocrine Tumors May Predict Responsiveness to BRAF-MEK Combination Therapy.

Neuroendocrine tumors comprise a heterogeneous group of malignancies with a broad spectrum of clinical behavior. Poorly differentiated tumors follow an aggressive course with limited treatment options, and new approaches are needed. Oncogenic BRAF V600E (BRAFV600E) substitutions are observed primarily in melanoma, colon cancer, and non-small cell lung cancer, but have been identified in multiple tumor types. Here we describe the first reported recurrent BRAFV600E mutations in advanced high grade colorectal neuroendocrine tumors, and identify BRAF alteration frequency of 9% in 108 cases. Among these BRAF alterations 80% were BRAFV600E. Dramatic response to BRAF-MEK combination occurred in two cases of metastatic high grade rectal neuroendocrine carcinoma refractory to standard therapy. Urinary BRAFV600E circulating tumor DNA monitoring paralleled disease response. Our series represents the largest study of genomic profiling in colorectal neuroendocrine tumors and provides strong evidence that BRAFV600E is an oncogenic driver responsive to BRAF/MEK combination therapy in this molecular subset.
Copyright ©2016, American Association for Cancer Research (AACR) (Free AACR Whitepaper).

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Targeted Doxorubicin Delivery to Brain Tumors via Minicells: Proof of Principle Using Dogs with Spontaneously Occurring Tumors as a Model.

Cytotoxic chemotherapy can be very effective for the treatment of cancer but toxicity on normal tissues often limits patient tolerance and often causes long-term adverse effects. The objective of this study was to assist in the preclinical development of using modified, non-living bacterially-derived minicells to deliver the potent chemotherapeutic doxorubicin via epidermal growth factor receptor (EGFR) targeting. Specifically, this study sought to evaluate the safety and efficacy of EGFR targeted, doxorubicin loaded minicells (designated EGFRminicellsDox) to deliver doxorubicin to spontaneous brain tumors in 17 companion dogs; a comparative oncology model of human brain cancers.
EGFRminicellsDox were administered weekly via intravenous injection to 17 dogs with late-stage brain cancers. Biodistribution was assessed using single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI). Anti-tumor response was determined using MRI, and blood samples were subject to toxicology (hematology, biochemistry) and inflammatory marker analysis. Targeted, doxorubicin-loaded minicells rapidly localized to the core of brain tumors. Complete resolution or marked tumor regression (>90% reduction in tumor volume) were observed in 23.53% of the cohort, with lasting anti-tumor responses characterized by remission in three dogs for more than two years. The median overall survival was 264 days (range 49 to 973). No adverse clinical, hematological or biochemical effects were observed with repeated administration of EGFRminicellsDox (30 to 98 doses administered in 10 of the 17 dogs).
Targeted minicells loaded with doxorubicin were safely administered to dogs with late stage brain cancer and clinical activity was observed. These findings demonstrate the strong potential for clinical applications of targeted, doxorubicin-loaded minicells for the effective treatment of patients with brain cancer. On this basis, we have designed a Phase 1 clinical study of EGFR-targeted, doxorubicin-loaded minicells for effective treatment of human patients with recurrent glioblastoma.

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