scholarly journals Hsp90 Inhibitors NVP-AUY922 and NVP-BEP800 May Exert a Significant Radiosensitization on Tumor Cells along with a Cell Type-Specific Cytotoxicity

2012 ◽  
Vol 5 (5) ◽  
pp. 356-IN16 ◽  
Author(s):  
Natalia Niewidok ◽  
Linda-Jacqueline Wack ◽  
Sarah Schiessl ◽  
Lavinia Stingl ◽  
Astrid Katzer ◽  
...  
2001 ◽  
Vol 21 (6) ◽  
pp. 2144-2153 ◽  
Author(s):  
Nabeel Bardeesy ◽  
Boris C. Bastian ◽  
Aram Hezel ◽  
Dan Pinkel ◽  
Ronald A. DePinho ◽  
...  

ABSTRACT The frequent loss of both INK4a and ARF in melanoma raises the question of which INK4a-ARF gene product functions to suppress melanoma genesis in vivo. Moreover, the high incidence of INK4a-ARF inactivation in transformed melanocytes, along with the lack of p53 mutation, implies a cell type-specific role for INK4a-ARF that may not be complemented by other lesions of the RB and p53 pathways. A mouse model of cutaneous melanoma has been generated previously through the combined effects of INK4a Δ2/3 deficiency (null for INK4a and ARF) and melanocyte-specific expression of activated RAS (tyrosinase-driven H-RASV12G, Tyr-RAS). In this study, we made use of this Tyr-RAS allele to determine whether activated RAS can cooperate withp53 loss in melanoma genesis, whether such melanomas are biologically comparable to those arising inINK4a Δ2/3−/− mice, and whether tumor-associated mutations emerge in the p16INK4a-RB pathway in such melanomas. Here, we report that p53inactivation can cooperate with activated RAS to promote the development of cutaneous melanomas that are clinically indistinguishable from those arisen on theINK4a Δ2/3 null background. Genomewide analysis of RAS-induced p53 mutant melanomas by comparative genomic hybridization and candidate gene surveys revealed alterations of key components governing RB-regulated G1/S transition, including c-Myc, cyclin D1, cdc25a, and p21CIP1. Consistent with the profile of c-Myc dysregulation, the reintroduction of p16INK4a profoundly reduced the growth of Tyr-RASINK4a Δ2/3−/− tumor cells but had no effect on tumor cells derived from Tyr-RAS p53 −/−melanomas. Together, these data validate a role for p53inactivation in melanomagenesis and suggest that both the RB and p53 pathways function to suppress melanocyte transformation in vivo in the mouse.


2017 ◽  
Vol 55 (05) ◽  
pp. e28-e56
Author(s):  
S Macheiner ◽  
R Gerner ◽  
A Pfister ◽  
A Moschen ◽  
H Tilg

2020 ◽  
Vol 528 (13) ◽  
pp. 2218-2238 ◽  
Author(s):  
Attilio Iemolo ◽  
Patricia Montilla‐Perez ◽  
I‐Chi Lai ◽  
Yinuo Meng ◽  
Syreeta Nolan ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hanyu Zhang ◽  
Ruoyi Cai ◽  
James Dai ◽  
Wei Sun

AbstractWe introduce a new computational method named EMeth to estimate cell type proportions using DNA methylation data. EMeth is a reference-based method that requires cell type-specific DNA methylation data from relevant cell types. EMeth improves on the existing reference-based methods by detecting the CpGs whose DNA methylation are inconsistent with the deconvolution model and reducing their contributions to cell type decomposition. Another novel feature of EMeth is that it allows a cell type with known proportions but unknown reference and estimates its methylation. This is motivated by the case of studying methylation in tumor cells while bulk tumor samples include tumor cells as well as other cell types such as infiltrating immune cells, and tumor cell proportion can be estimated by copy number data. We demonstrate that EMeth delivers more accurate estimates of cell type proportions than several other methods using simulated data and in silico mixtures. Applications in cancer studies show that the proportions of T regulatory cells estimated by DNA methylation have expected associations with mutation load and survival time, while the estimates from gene expression miss such associations.


2021 ◽  
Author(s):  
Moataz Dowaidar

Autophagy is a double-edged sword in cancer, and numerous aspects should be taken into account before deciding on the most effective strategy to target the process. The fact that several clinical studies are now ongoing does not mean that the patient group that may benefit from autophagy-targeting medicines has been identified. Autophagy inhibitors that are more potent and specialized, as well as autophagy indicators, are also desperately required. The fact that these inhibitors only work against tumors that rely on autophagy for survival (RAS mutants) makes it difficult to distinguish them from tumors that continue to develop even when autophagy is absent. Furthermore, mutations such as BRAF have been shown to make tumors more susceptible to autophagy suppression, suggesting that targeting such tumours may be a viable strategy for overcoming their chemotherapy resistance. In the meantime, we are unable to identify if autophagy regulation works in vivo or whether it selectively targets a disease while inflicting injury to other healthy organs and tissues. A cell-type-specific impact appears to be observed with such therapy. As a result, it is just as important to consider the differences between tumors that originate in different organs as it is to consider the signaling pathways that are similar across them. For a therapy or cure to be effective, the proposed intervention must be tailored to the specific needs of each patient.Over the last several years, a growing amount of data has implicated autophagy in a variety of disorders, including cancer. In normal cells, this catabolic process is also required for cell survival and homeostasis. Despite the fact that medications targeting intermediates in the autophagy signaling pathway are being created and evaluated at both the preclinical and clinical levels, given the complicated function of autophagy in cancer, we still have a long way to go in terms of establishing an effective therapeutic approach. This article discusses current tactics for exploiting cancer cells' autophagy dependency, as well as obstacles in the area. We believe that the unanswered concerns raised in this work will stimulate researchers to investigate previously unknown connections between autophagy and other signaling pathways, which might lead to the development of novel, highly specialized autophagy therapies.


1993 ◽  
Vol 13 (9) ◽  
pp. 5301-5314 ◽  
Author(s):  
G S Huh ◽  
R O Hynes

We have investigated the regulation of splicing of one of the alternatively spliced exons in the rat fibronectin gene, the EIIIB exon. This 273-nucleotide exon is excluded by some cells and included to various degrees by others. We find that EIIIB is intrinsically poorly spliced and that both its exon sequences and its splice sites contribute to its poor recognition. Therefore, cells which recognize the EIIIB exon must have mechanisms for improving its splicing. Furthermore, in order for EIIB to be regulated, a balance must exist between the EIIIB splice sites and those of its flanking exons. Although the intron upstream of EIIIB does not appear to play a role in the recognition of EIIIB for splicing, the intron downstream contains sequence elements which can promote EIIIB recognition in a cell-type-specific fashion. These elements are located an unusually long distance from the exon that they regulate, more than 518 nucleotides downstream from EIIIB, and may represent a novel mode of exon regulation.


2000 ◽  
Vol 191 (8) ◽  
pp. 1281-1292 ◽  
Author(s):  
Raelene J. Grumont ◽  
Steve Gerondakis

In lymphocytes, the Rel transcription factor is essential in establishing a pattern of gene expression that promotes cell proliferation, survival, and differentiation. Here we show that mitogen-induced expression of interferon (IFN) regulatory factor 4 (IRF-4), a lymphoid-specific member of the IFN family of transcription factors, is Rel dependent. Consistent with IRF-4 functioning as a repressor of IFN-induced gene expression, the absence of IRF-4 expression in c-rel−/− B cells coincided with a greater sensitivity of these cells to the antiproliferative activity of IFNs. In turn, enforced expression of an IRF-4 transgene restored IFN modulated c-rel−/− B cell proliferation to that of wild-type cells. This cross-regulation between two different signaling pathways represents a novel mechanism that Rel/nuclear factor κB can repress the transcription of IFN-regulated genes in a cell type–specific manner.


2018 ◽  
Vol 25 (3) ◽  
pp. 1143-1152 ◽  
Author(s):  
Yunmei Zhang ◽  
Jieru Xu ◽  
Dairong Li ◽  
Tao Wan ◽  
Qianfang Hu

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