Inosine pranobex enhances human NK cell cytotoxicity by inducing metabolic activation and NKG2D ligand expression.

Inosine pranobex (IP) is a synthetic immunomodulating compound, indicated for use in the treatment of human papillomavirus-associated warts and subacute sclerosing panencephalitis. Previous studies demonstrate that the immunomodulatory activity of IP is characterized by enhanced lymphocyte proliferation, cytokine production, and NK cell cytotoxicity. The activation of NKG2D signaling on NK cells, CD8+ T cells, and γδ T cells also produces these outcomes. We hypothesized that IP alters cellular immunity through the induction of NKG2D ligand expression on target cells, thereby enhancing immune cell activation through the NKG2D receptor. We tested this hypothesis and show that exposure of target cells to IP leads to increased expression of multiple NKG2D ligands. Using both targeted metabolic interventions and unbiased metabolomic studies, we found that IP causes an increase in intracellular concentration of purine nucleotides and tricarboxylic acid (TCA) cycle intermediates and NKG2D ligand induction. The degree of NKG2D ligand induction was functionally significant, leading to increased NKG2D-dependent target cell immunogenicity. These findings demonstrate that the immunomodulatory properties of IP are due to metabolic activation with NKG2D ligand induction.

Purine nucleotide metabolism regulates expression of the human immune ligand MICA.

Expression of the cell-surface glycoprotein MHC class I polypeptide-related sequence A (MICA) is induced in dangerous, abnormal, or "stressed" cells, including cancer cells, virus-infected cells, and rapidly proliferating cells. MICA is recognized by the activating immune cell receptor natural killer group 2D (NKG2D), providing a mechanism by which immune cells can identify and potentially eliminate pathological cells. Immune recognition through NKG2D is implicated in cancer, atherosclerosis, transplant rejection, and inflammatory diseases, such as rheumatoid arthritis. Despite the wide range of potential therapeutic applications of MICA manipulation, the factors that control MICA expression are unclear. Here we use metabolic interventions and metabolomic analyses to show that the transition from quiescent cellular metabolism to a "Warburg" or biosynthetic metabolic state induces MICA expression. Specifically, we show that glucose transport into the cell and active glycolytic metabolism are necessary to up-regulate MICA expression. Active purine synthesis is necessary to support this effect of glucose, and increases in purine nucleotide levels are sufficient to induce MICA expression. Metabolic induction of MICA expression directly influences NKG2D-dependent cytotoxicity by immune cells. These findings support a model of MICA regulation whereby the purine metabolic activity of individual cells is reflected by cell-surface MICA expression and is the subject of surveillance by NKG2D receptor-expressing immune cells.

PeaKDEck: a kernel density estimator-based peak calling program for DNaseI-seq data.

Hypersensitivity to DNaseI digestion is a hallmark of open chromatin, and DNaseI-seq allows the genome-wide identification of regions of open chromatin. Interpreting these data is challenging, largely because of inherent variation in signal-to-noise ratio between datasets. We have developed PeaKDEck, a peak calling program that distinguishes signal from noise by randomly sampling read densities and using kernel density estimation to generate a dataset-specific probability distribution of random background signal. PeaKDEck uses this probability distribution to select an appropriate read density threshold for peak calling in each dataset. We benchmark PeaKDEck using published ENCODE DNaseI-seq data and other peak calling programs, and demonstrate superior performance in low signal-to-noise ratio datasets.

Solid-phase plate-reader quantification of specific PCR products by measurement of band-specific ethidium bromide fluorescence.

Real-time PCR is widely employed to quantify PCR products across a range of applications. However, accurate real-time PCR is not always technically feasible, and alternative methods for PCR product quantification can be expensive and time consuming to validate. We have developed an inexpensive, rapid, and immediately accessible protocol to quantify PCR products, by measuring ethidium bromide fluorescence of PCR products excised from agarose gels. This protocol has relevance to a broad range of methods in molecular biology where quantification of PCR products is necessary.

Successful capecitabine rechallenge following 5-fluorouracil-induced Takotsubo syndrome.

Cardiac toxicity is a widely reported complication of fluoropyrimidine chemotherapies (5-fluorouracil and capecitabine); however, Takotsubo syndrome (TS) is less widely reported. There is little data available describing the viability of fluoropyrimidine rechallenge after fluoropyrimidine-induced TS. We report the case of Ms X, a 41-year-old woman with metastatic oesophageal cancer, who developed acute onset left ventricular dysfunction, with a measured left ventricular ejection fraction of 15% on cycle 1 day 3 of FOLFOX chemotherapy, after disconnection of the fluorouracil infusion pump. Her symptoms resolved over 2 days, and an echocardiogram returned to normal within 2 weeks. 5-Fluorouracil was discontinued, and replaced with capecitabine, without recurrence of symptoms. The remainder of her treatment was uneventful. This is the second case to describe successful capecitabine retreatment following 5-fluorouracil-induced TS.

Prostate cancer metastasis to calcaneus: a solitary lesion at an atypical site, dormant for more than 10 years.

In prostate cancer patients, if bone scan demonstrates a solitary lesion in atypical area, this is possibly an indication of metastatic disease. Therefore, biopsy confirmation is required to determine the nature of the abnormality and therefore dictates further staging investigations and treatment options.

Infiltrative thyrotoxicosis: an unusual case of diffuse large B cell lymphoma.

Thyrotoxicosis is most commonly caused by Graves' disease, toxic multinodular goitre, a functioning thyroid adenoma, or thyroiditis. Extrinsic infiltrative conditions affecting the thyroid gland are typically destructive, and associated with thyroid hypofunction. We describe the case of a 61-year-old woman who presented to our hospital with symptoms of thyrotoxicosis, neck swelling and thyroid function tests consistent with hyperthyroidism. An ultrasound revealed a multinodular goitre with retrosternal extension, but CT imaging suggested thyroid gland infiltration, with cervical lymphadenopathy. An excisional lymph node biopsy confirmed the diagnosis of diffuse large B cell lymphoma causing infiltrative thyrotoxicosis. Treatment with six cycles of Rituximab-CHOP lead to rapid normalization of symptoms, imaging, and thyroid function.

MICA Expression Is Regulated by Cell Adhesion and Contact in a FAK/Src-Dependent Manner.

MICA is a major ligand for the NKG2D immune receptor, which plays a key role in activating natural killer (NK) cells and cytotoxic T cells. We analyzed NKG2D ligand expression on a range of cell types and could demonstrate that MICA expression levels were closely linked to cellular growth mode. While the expression of other NKG2D ligands was largely independent of cell growth mode, MICA expression was mainly found on cells cultured as adherent cells. In addition, MICA surface expression was reduced through increase in cell-cell contact or loss of cell-matrix adherence. Furthermore, we found that the reduction in MICA expression was modulated by focal adhesion kinase (FAK)/Src signaling and associated with increased susceptibility to NK cell-mediated killing. While the mechanisms of tumor immune evasion are not fully understood, the reduction of MICA expression following loss of attachment poises a potential way by which metastasizing tumor cells avoid immune detection. The role of FAK/Src in this process indicates a potential therapeutic approach to modulate MICA expression and immune recognition of tumor cells during metastasis.