PICS-ure This: Prosenescence Therapy?

Senescence is increasingly recognized as a critical feature of mammalian cells to suppress tumorigenesis, acting together with cell death programs. Whether senescence, like programmed cell death, can be exploited therapeutically has been unclear. Pandolfi and coworkers now propose that PTEN-loss-induced cellular senescence (PICS) may be triggered in vivo for therapy

In vivo RNAi screening for novel therapeutic cancer targets

International Symposium on Tumor Biology in Kanazawa & Symposium on Drug Discoverry in Academics 2014 [DATE]: January 23(Thu)-24(Fri),2014, [Place]:Kanazawa Excel Hotel Tpkyu, Kanazawa, Japan, [Organizers]:Kanazawa Association of Tumor Biologists / Cancer Research Institute, Kanazawa Universit

Autophagy-mediated degradation of nuclear envelope proteins during oncogene-induced senescence

Here, we report that nuclear envelope proteins are subjected to autophagic proteolysis in human cells undergoing oncogene-induced senescence. This degradation occurs in parallel with autophagy and lysosomal activity induction that accompanies the establishment of the senescence respons

Підготовка адвокатом позовної заяви до суду

Аналізуються питання, пов’язані із підготовкою адвокатом позовної заяви до суду.Анализируется вопросы связаны с подготовкой адвокатом искового заявления в суд.The question connected with preparation of the point of claim to the court by the lawyer is analysed

Fatty acid 16:4(n-3) stimulates a GPR120-induced signaling cascade in splenic macrophages to promote chemotherapy resistance

Although chemotherapy is designed to eradicate tumor cells, it also has significant effects on normal tissues. The platinum-induced fatty acid 16:4(n-3) (hexadeca-4,7,10,13-tetraenoic acid) induces systemic resistance to a broad range of DNA-damaging chemotherapeutics. We show that 16:4(n-3) exerts its effect by activating splenic F4/80+/CD11blow macrophages, which results in production of chemoprotective lysophosphatidylcholines (LPCs). Pharmacologic studies, together with analysis of expression patterns, identified GPR120 on F4/80+/CD11blow macrophages as the relevant receptor for 16:4(n-3). Studies that used splenocytes from GPR120-deficient mice have confirmed this conclusion. Activation of the 16:4(n-3)-GPR120 axis led to enhanced cPLA2 activity in these splenic macrophages and secretion of the resistance-inducing lipid mediator, lysophosphatidylcholine(24:1). These studies identify a novel and unexpected function for GPR120 and suggest that antagonists of this receptor might be effective agents to limit development of chemotherapy resistance.—Houthuijzen, J. M., Oosterom, I., Hudson, B. D., Hirasawa, A., Daenen, L. G. M., McLean, C. M., Hansen, S. V. F., van Jaarsveld, M. T. M., Peeper, D. S., Jafari Sadatmand, S., Roodhart, J. M. L., van de Lest, C. H. A., Ulven, T., Ishihara, K., Milligan, G., Voest, E. E. Fatty acid 16:4(n-3) stimulates a GPR120-induced signaling cascade in splenic macrophages to promote chemotherapy resistance

BRAF(E600)-associated senescence-like cell cycle arrest of human naevi

Most normal mammalian cells have a finite lifespan(1), thought to constitute a protective mechanism against unlimited proliferation(2-4). This phenomenon, called senescence, is driven by telomere attrition, which triggers the induction of tumour suppressors including p16(INK4a) (ref. 5). In cultured cells, senescence can be elicited prematurely by oncogenes(6); however, whether such oncogene-induced senescence represents a physiological process has long been debated. Human naevi ( moles) are benign tumours of melanocytes that frequently harbour oncogenic mutations ( predominantly V600E, where valine is substituted for glutamic acid) in BRAF(7), a protein kinase and downstream effector of Ras. Nonetheless, naevi typically remain in a growth-arrested state for decades and only rarely progress into malignancy (melanoma)(8-10). This raises the question of whether naevi undergo BRAF(V600E)- induced senescence. Here we show that sustained BRAF(V600E) expression in human melanocytes induces cell cycle arrest, which is accompanied by the induction of both p16(INK4a) and senescence- associated acidic beta-galactosidase (SA-beta-Gal) activity, a commonly used senescence marker. Validating these results in vivo, congenital naevi are invariably positive for SA-beta-Gal, demonstrating the presence of this classical senescence-associated marker in a largely growth-arrested, neoplastic human lesion. In growth-arrested melanocytes, both in vitro and in situ, we observed a marked mosaic induction of p16(INK4a), suggesting that factors other than p16(INK4a) contribute to protection against BRAF(V600E)- driven proliferation. Naevi do not appear to suffer from telomere attrition, arguing in favour of an active oncogene-driven senescence process, rather than a loss of replicative potential. Thus, both in vitro and in vivo, BRAF(V600E)-expressing melanocytes display classical hallmarks of senescence, suggesting that oncogene-induced senescence represents a genuine protective physiological process.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62941/1/nature03890.pd

Parallel In Vivo and In Vitro Melanoma RNAi Dropout Screens Reveal Synthetic Lethality between Hypoxia and DNA Damage Response Inhibition

SummaryTo identify factors preferentially necessary for driving tumor expansion, we performed parallel in vitro and in vivo negative-selection short hairpin RNA (shRNA) screens. Melanoma cells harboring shRNAs targeting several DNA damage response (DDR) kinases had a greater selective disadvantage in vivo than in vitro, indicating an essential contribution of these factors during tumor expansion. In growing tumors, DDR kinases were activated following hypoxia. Correspondingly, depletion or pharmacologic inhibition of DDR kinases was toxic to melanoma cells, including those that were resistant to BRAF inhibitor, and this could be enhanced by angiogenesis blockade. These results reveal that hypoxia sensitizes melanomas to targeted inhibition of the DDR and illustrate the utility of in vivo shRNA dropout screens for the identification of pharmacologically tractable targets

SUMOylation of DRIL1 Directs Its Transcriptional Activity Towards Leukocyte Lineage-Specific Genes

DRIL1 is an ARID family transcription factor that can immortalize primary mouse fibroblasts, bypass RASV12-induced cellular senescence and collaborate with RASV12 or MYC in mediating oncogenic transformation. It also activates immunoglobulin heavy chain transcription and engages in heterodimer formation with E2F to stimulate E2F-dependent transcription. Little, however, is known about the regulation of DRIL1 activity. Recently, DRIL1 was found to interact with the SUMO-conjugating enzyme Ubc9, but the functional relevance of this association has not been assessed. Here, we show that DRIL1 is sumoylated both in vitro and in vivo at lysine 398. Moreover, we provide evidence that PIASy functions as a specific SUMO E3-ligase for DRIL1 and promotes its sumoylation both in vitro and in vivo. Furthermore, consistent with the subnuclear localization of PIASy in the Matrix-Associated Region (MAR), SUMO-modified DRIL1 species are found exclusively in the MAR fraction. This post-translational modification interferes neither with the subcellular localization nor the DNA-binding activity of the protein. In contrast, DRIL1 sumoylation impairs its interaction with E2F1 in vitro and modifies its transcriptional activity in vivo, driving transcription of subset of genes regulating leukocyte fate. Taken together, these results identify sumoylation as a novel post-translational modification of DRIL1 that represents an important mechanism for targeting and modulating DRIL1 transcriptional activity

Vemurafenib plus cobimetinib in unresectable stage IIIc or stage IV melanoma:Response monitoring and resistance prediction with positron emission tomography and tumor characteristics (REPOSIT): study protocol of a phase II, open-label, multicenter study

BACKGROUND: In patients with BRAFV600 mutated unresectable stage IIIc or metastatic melanoma, molecular targeted therapy with combined BRAF/MEK-inhibitor vemurafenib plus cobimetinib has shown a significantly improved progression-free survival and overall survival compared to treatment with vemurafenib alone. Nevertheless, the majority of BRAFV600 mutation-positive melanoma patients will eventually develop resistance to treatment. Molecular imaging with F-18-Fluorodeoxyglucose (F-18-FDG) PET has been used to monitor response to vemurafenib in some BRAFV600 mutated metastatic melanoma patients, showing a rapid decline of F-18-FDG uptake within 2 weeks following treatment. Furthermore, preliminary results suggest that metabolic alterations might predict the development of resistance to treatment. F-18-Fluoro-3'-deoxy-3' L-fluorothymidine (F-18-FLT), a PET-tracer visualizing proliferation, might be more suitable to predict response or resistance to therapy than F-18-FDG. METHODS: This phase II, open-label, multicenter study evaluates whether metabolic response to treatment with vemurafenib plus cobimetinib in the first 7 weeks as assessed by F-18-FDG/F-18-FLT PET can predict progression-free survival and whether early changes in F-18-FDG/F-18-FLT can be used for early detection of treatment response compared to standard response assessment with RECISTv1.1 ceCT at 7 weeks. Ninety patients with BRAFV600E/K mutated unresectable stage IIIc/IV melanoma will be included. Prior to and during treatment all patients will undergo F-18-FDG PET/CT and in 25 patients additional F-18-FLT PET/CT is performed. Histopathological tumor characterization is assessed in a subset of 40 patients to unravel mechanisms of resistance. Furthermore, in all patients, blood samples are taken for pharmacokinetic analysis of vemurafenib/cobimetinib. Outcomes are correlated with PET/CT-imaging and therapy response. DISCUSSION: The results of this study will help in linking PET measured metabolic alterations induced by targeted therapy of BRAFV600 mutated melanoma to molecular changes within the tumor. We will be able to correlate both F-18-FDG and F-18-FLT PET to outcome and decide on the best modality to predict long-term remissions to combined BRAF/MEK-inhibitors. Results coming from this study may help in identifying responders from non-responders early after the initiation of therapy and reveal early development of resistance to vemurafenib/cobimetinib. Furthermore, we believe that the results can be fundamental for further optimizing individual patient treatment