LNK suppresses interferon signaling in melanoma.

LNK (SH2B3) is a key negative regulator of JAK-STAT signaling which has been extensively studied in malignant hematopoietic diseases. We found that LNK is significantly elevated in cutaneous melanoma; this elevation is correlated with hyperactive signaling of the RAS-RAF-MEK pathway. Elevated LNK enhances cell growth and survival in adverse conditions. Forced expression of LNK inhibits signaling by interferon-STAT1 and suppresses interferon (IFN) induced cell cycle arrest and cell apoptosis. In contrast, silencing LNK expression by either shRNA or CRISPR-Cas9 potentiates the killing effect of IFN. The IFN-LNK signaling is tightly regulated by a negative feedback mechanism; melanoma cells exposed to IFN upregulate expression of LNK to prevent overactivation of this signaling pathway. Our study reveals an unappreciated function of LNK in melanoma and highlights the critical role of the IFN-STAT1-LNK signaling axis in this potentially devastating disease. LNK may be further explored as a potential therapeutic target for melanoma immunotherapy

Dynamics, Alterations, and Consequences of Minimally Invasive Intraocular Pressure Elevation in Rats

Citation: Gramlich OW, Lueckner TCS, Kriechbaum M, et al. Dynamics, alterations, and consequences of minimally invasive intraocular pressure elevation in rats. Invest Ophthalmol Vis Sci. 2014;55:600-611. DOI: 10.1167/iovs. PURPOSE. An important, yet not exclusive, aspect of primary open angle glaucoma is elevated intraocular pressure (IOP) profiles within fluctuations and pressure peaks. The study aimed at establishing minimally invasive methods for recurrent IOP elevation in rats to investigate the impact of IOP dynamics and pathomorphologic retinal alterations during and after IOP elevation. METHODS. Intraocular pressure was elevated unilaterally in Long Evans rats to a level of »35 mm Hg for 1 hour in a total of 30 manipulations within 6 weeks, by using two methods: (1) suction-cup oculopression and (2) loop-adjusted oculopression. Retinal thickness (RT) was measured via optical coherence tomography (OCT), and neuronal survival was analyzed. Additional experiments were performed for ''in situ'' OCT investigations during exposures to different IOP levels. RESULTS. A mean IOP exposure of þ737.3 6 9.6 DIOP mm Hg for loop adjustment and þ188.9 6 16 DIOP mm Hg for suction cup was achieved. Optical coherence tomography examination revealed notable changes of RT between controls, untreated, and treated eyes, and evaluation of neuronal loss showed a significant decrease of retinal ganglion cell (RGC) density in both groups. In situ OCT investigation showed paradoxical retinal distortion and deformation of the optic nerve head toward the eye background. CONCLUSIONS. After accurate IOP elevation with minimally invasive methods, it was possible to detect RGC loss and retinal thinning. While suction cup is capable of simulating accurate arbitrary IOP profiles, loop adjustment enables the detection of pressure-dependent retinal alterations. For the first time, it was feasible to investigate consequences of variable IOP elevation profiles, including pressure peaks, by using real-time live imaging in vivo. Keywords: recurrent IOP elevation, OCT imaging, retinal degeneration, ''in situ'' imaging T he pathology of glaucoma is still subject to research. In general, it is considered a multifactorial, heterogeneous group of ocular diseases and is the second most common cause of human blindness worldwide. 1 Furthermore, it is defined by a progressive and irreversible loss of retinal ganglion cells (RGCs) and their axons, 2 which leads to visual field loss in more advanced stages. 3 Glaucoma is often associated with an elevated intraocular pressure (IOP), 4 but solely 60% to 75% of the patients who suffer from primary open angle glaucoma (POAG) show an IOP elevation of more than 21 mm Hg. 5 Several studies have demonstrated that an elevated IOP does not remain at a stable level, but rather that it underlies strong dynamics including IOP fluctuations, pressure peaks, and circadian variations of approximately 10% to 20% (up to 64 mm Hg). 6-8 Moreover, there are hints of a relationship between IOP fluctuations and increased mean IOP, which further impacts the visual field. 9-12 While half of these studies indicate a direct link to disease progression, others do not. On the other hand, the remaining 25% to 35% of the glaucoma patients suffering from normal tension glaucoma manifest glaucomatous symptoms without significant elevation of the IOP. 14 By now, numerous different hypotheses concerning the pathogenesis exist, but none is sufficient to elucidate the disease pattern on its own. It is assumed that the interaction of individual pathomechanisms, such as IOP-dependent and IOP-independent dysregulations of the ocular blood flow and retinal ischemia, lead to the final loss of RGCs. These pressureinduced dysfunctions and autoregulations in retinal blood vessels often lead to RGC loss by, for example, anoxia and reperfusion injury

Development of a taste-masked orodispersible film containing dimenhydrinate

Orodispersible dosage forms are promising new approaches for drug delivery. They enable an easy application, as there is no need to drink high amounts of liquids or swallow large solid dosage forms. The aim of the study was to develop an orodispersible film (ODF) as an alternative to tablets, syrups or suppositories for the treatment of vomiting and nausea, especially for the pediatric population. Formulations were investigated by X-ray diffraction, scanning electron and polarized light microscopy. Additionally, two commercially available electronic taste sensing systems were used to investigate the applied taste-masking strategies. Results obtained from X-ray-diffraction and polarized light microscopy showed no recrystallization of dimenhydrinate in the formulation when cyclodextrin or maltodextrin were used as solubilizing and complexing agent. All ODFs showed fast disintegration depending on the characterization method. In order to get taste information, the dimenhydrinate formulations were analytically compared to pure drug and drug-free formulations by electronic tongues. Results obtained from both systems are comparable and were used together for the first time. It was possible to develop an ODF of dimenhydrinate that is fast disintegrating even in small volumes of liquid. Furthermore, in vitro taste assessment by two electronic tongues revealed taste-masking effects by the excipients

Stress signaling in breast cancer cells induces matrix components that promote chemoresistant metastasis

Abstract Metastatic progression remains a major burden for cancer patients and is associated with eventual resistance to prevailing therapies such as chemotherapy. Here, we reveal how chemotherapy induces an extracellular matrix (ECM), wound healing, and stem cell network in cancer cells via the c‐Jun N‐terminal kinase (JNK) pathway, leading to reduced therapeutic efficacy. We find that elevated JNK activity in cancer cells is linked to poor clinical outcome in breast cancer patients and is critical for tumor initiation and metastasis in xenograft mouse models of breast cancer. We show that JNK signaling enhances expression of the ECM and stem cell niche components osteopontin, also called secreted phosphoprotein 1 (SPP1), and tenascin C (TNC), that promote lung metastasis. We demonstrate that both SPP1 and TNC are direct targets of the c‐Jun transcription factor. Exposure to multiple chemotherapies further exploits this JNK‐mediated axis to confer treatment resistance. Importantly, JNK inhibition or disruption of SPP1 or TNC expression sensitizes experimental mammary tumors and metastases to chemotherapy, thus providing insights to consider for future treatment strategies against metastatic breast cancer

Preneoplastic stromal cells promote BRCA1-mediated breast tumorigenesis

Women with germline BRCA1 mutations (BRCA1+/mut) have increased risk for hereditary breast cancer. Cancer initiation in BRCA1+/mut is associated with premalignant changes in breast epithelium; however, the role of the epithelium-associated stromal niche during BRCA1-driven tumor initiation remains unclear. Here we show that the premalignant stromal niche promotes epithelial proliferation and mutant BRCA1-driven tumorigenesis in trans. Using single-cell RNA sequencing analysis of human preneoplastic BRCA1+/mut and noncarrier breast tissues, we show distinct changes in epithelial homeostasis including increased proliferation and expansion of basal-luminal intermediate progenitor cells. Additionally, BRCA1+/mut stromal cells show increased expression of pro-proliferative paracrine signals. In particular, we identify pre-cancer-associated fibroblasts (pre-CAFs) that produce protumorigenic factors including matrix metalloproteinase 3 (MMP3), which promotes BRCA1-driven tumorigenesis in vivo. Together, our findings demonstrate that precancerous stroma in BRCA1+/mut may elevate breast cancer risk through the promotion of epithelial proliferation and an accumulation of luminal progenitor cells with altered differentiation

LNK suppresses interferon signaling in melanoma.

LNK (SH2B3) is a key negative regulator of JAK-STAT signaling which has been extensively studied in malignant hematopoietic diseases. We found that LNK is significantly elevated in cutaneous melanoma; this elevation is correlated with hyperactive signaling of the RAS-RAF-MEK pathway. Elevated LNK enhances cell growth and survival in adverse conditions. Forced expression of LNK inhibits signaling by interferon-STAT1 and suppresses interferon (IFN) induced cell cycle arrest and cell apoptosis. In contrast, silencing LNK expression by either shRNA or CRISPR-Cas9 potentiates the killing effect of IFN. The IFN-LNK signaling is tightly regulated by a negative feedback mechanism; melanoma cells exposed to IFN upregulate expression of LNK to prevent overactivation of this signaling pathway. Our study reveals an unappreciated function of LNK in melanoma and highlights the critical role of the IFN-STAT1-LNK signaling axis in this potentially devastating disease. LNK may be further explored as a potential therapeutic target for melanoma immunotherapy