scholarly journals AIRE controls the expression of IFIT3 in the thymus.

2020 ◽  
Author(s):  
Shahan Mamoor

Comparing the transcriptomes of a thymic cell line engineered to over-express the autoimmune regulator gene AIRE with that of its parental cell line using a public dataset (1) revealed that IFIT1, IFIT2 and IFIT3 were among the genes whose expression changed most significantly upon expression of AIRE, with a substantial increase in IFIT1, IFIT2, and IFIT3 expression. Analysis of a separate dataset showed that in the thymuses of mice engineered to lack a functional copy of the AIRE gene (2), IFIT3 expression was greatly reduced. After either deletion or ectopic expression of Aire, IFIT3 was identified as one of the most differentially expressed genes. IFIT3 expression was found to co-segregate with low rather than high expression of the class II antigen presentation complex MHC-II (3). We conclude that AIRE exerts control over the gene expression of IFIT3 through an as-of-yet unidentified mechanism not likely to reflect AIRE’s role as a transcriptional inducer of gene expression of peripheral tissue antigens.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5017-5017
Author(s):  
Susan K Rathe ◽  
David Largaespada

Abstract Acute myeloid leukemia (AML) has the ability to evade cell death in the presence of chemotherapeutic cocktails containing cytosine arabinoside (Ara-C). This lab previously developed two highly resistant murine AML cell lines, B117H and B140H, by introducing increasing concentrations of Ara-C to their parental cell lines, B117P and B140P, respectively. B117H and B140H can tolerate Ara-C concentrations ~1000X that of their drug sensitive parental cell lines. mRNA from all four cell lines were used in gene expression microarrays for the purpose of comparing Ara-C drug resistant murine AML cell lines with their Ara-C drug sensitive parental lines. A novel algorithm was developed to evaluate the changes in gene expression between the drug resistant and drug sensitive cells. The algorithm differed from more conventional algorithms in two key ways. First, the detection data was normalized by using ribosomal subunit 9 (Rsp9) as the normalization gene, and secondly it calculated fold change by comparing the minimum value of one population to the maximum value of the other population. The output of this algorithm was a list of genes with significant gene expression changes. These genes were next submitted to the Ingenuity Pathway Analysis (IPA) process. IPA implicated nuclear factor-κB (NFκB) in the Ara-C resistance process. Cell growth assays confirmed that the Ara-C drug resistant B117H cell line was significantly more sensitive to NFκB inhibition than its Ara-C sensitive parental cell line. This leads us to believe that the selection of Ara-C resistance may also concomitantly make some AML cells highly sensitive to killing by NFκB inhibition. This theory is being tested further through the use of drug combination assays, to determine if a synergistic or antagonistic relationship exists between Ara-C and various drugs that affect the NFκB pathway.


Cancer ◽  
2002 ◽  
Vol 95 (8) ◽  
pp. 1663-1672 ◽  
Author(s):  
Xin Zhang ◽  
Yanna Liu ◽  
Michael Z. Gilcrease ◽  
Xiao H. Yuan ◽  
Gary L. Clayman ◽  
...  

Author(s):  
Fatma Kubra Ata ◽  
Serap Yalcin

Background: Chemotherapeutics have been commonly used in cancer treatment. Objective: In this study, the effects of Cisplatin, 5-fluorouracil, Irinotecan, and Gemcitabine have been evaluated on two-dimensional (2D) (sensitive and resistance) cell lines and three dimensional (3D) spheroid structure of MDA-MB-231. The 2D cell culture lacks a natural tissue-like structural so, using 3D cell culture has an important role in the development of effective drug testing models. Furthermore, we analyzed the ATP Binding Cassette Subfamily G Member 2 (ABCG2) gene and protein expression profile in this study. We aimed to establish a 3D breast cancer model that can mimic the in vivo 3D breast cancer microenvironment. Methods: The 3D spheroid structures were multiplied (globally) using the three-dimensional hanging drop method. The cultures of the parental cell line MDA-MB-231 served as the controls. After adding the drugs in different amounts we observed a clear and well-differentiated spheroid formation for 24 h. The viability and proliferation capacity of 2D (sensitive and resistant) cell lines and 3D spheroid cell treatment were assessed by the XTT assay. Results: Cisplatin, Irinotecan, 5-Fu, and Gemcitabine-resistant MDA-MB-231 cells were observed to begin to disintegrate in a three-dimensional clustered structure at 24 hours. Additionally, RT-PCR and protein assay showed overexpression of ABCG2 when compared to the parental cell line. Moreover, MDA-MB-231 cells grown in 3D showed decreased sensitivity to chemotherapeutics treatment. Conclusion: More resistance to chemotherapeutics and altered gene expression profile was shown in 3D cell cultures when compared with the 2D cells. These results might play an important role to evaluate the efficacy of anticancer drugs, explore mechanisms of MDR in the 3D spheroid forms.


1985 ◽  
Vol 5 (10) ◽  
pp. 2527-2532
Author(s):  
C H Jenh ◽  
P K Geyer ◽  
L F Johnson

We studied the content and metabolism of thymidylate synthase mRNA in cultured mouse fibroblasts that were undergoing a serum-induced transition from the resting to growing state. The studies were performed with a 5-fluorodeoxyuridine-resistant 3T6 cell line (LU3-7) that over produces the enzyme and its mRNA about 50-fold and that regulates the expression of the thymidylate synthase gene in the same manner as the parental cell line. We have previously shown that the rate of synthesis of thymidylate synthase increases at least ninefold when the serum-stimulated cells traverse the S phase. Here we show, by Northern blot analysis, that thymidylate synthase mRNA increased 20- to 40-fold as cells progressed from resting to late S phase. About 85% of poly(A)+ thymidylate synthase mRNA was associated with polysomes at all times. The increase in thymidylate synthase poly(A)+ mRNA content was the result of an eightfold increase in the rate of production of this species, as shown by pulse-labeling studies. Pulse-chase analysis revealed that the half-life of thymidylate synthase poly(A)+ mRNA was similar in resting (9 h) and growing (7 h) cells. The rate of transcription of the thymidylate synthase gene, as determined in isolated nuclei, increased only by a factor of three to four during the S phase. Since the content of the message increased to a much greater extent than the rate of transcription of the gene, posttranscriptional controls must also play a role in regulating the content of thymidylate synthase mRNA under these conditions. Our results suggest that the cell may regulate the distribution of thymidylate synthase mRNA between a relatively stable poly(A)+ RNA species and a labile poly(A)- RNA species.


1992 ◽  
Vol 12 (3) ◽  
pp. 1179-1187 ◽  
Author(s):  
F Ståhl ◽  
Y Wettergren ◽  
G Levan

Multidrug resistance (MDR) in tumor cell lines is frequently correlated with amplification of one or more mdr genes. Usually the amplified domain also includes several neighboring genes. Using pulsed-field gel electrophoresis, we have established a restriction map covering approximately 2,200 kb in the drug-sensitive mouse tumor cell line TC13K. The mapped region is located on mouse chromosome 5 and includes the three mdr genes, the gene for the calcium-binding sorcin protein, and a gene with unknown function designated class 5. Long-range maps of the amplified DNA sequences in five of six MDR sublines that had been independently derived from TC13K generally displayed the same pattern as did the parental cell line. All six MDR sublines exhibited numerous double minutes, and one of them displayed a homogeneously staining region in a subpopulation. Large circular molecules, most likely identical to one chromatid of the double minutes, were detected in four of the sublines by linearization with gamma irradiation. The size of the circles was about 2,500 kb, which correlated to a single unit of the amplified domain. We therefore propose that in four independent instances of MDR development, a single unit of about 2,500 kb has been amplified in the form of circular DNA molecules. The restriction enzyme map of the amplified unit is unchanged compared with that of the parental cell line, whereas the joining sites of the circular DNA molecules are not identical but are in the same region.


1985 ◽  
Vol 5 (10) ◽  
pp. 2527-2532 ◽  
Author(s):  
C H Jenh ◽  
P K Geyer ◽  
L F Johnson

We studied the content and metabolism of thymidylate synthase mRNA in cultured mouse fibroblasts that were undergoing a serum-induced transition from the resting to growing state. The studies were performed with a 5-fluorodeoxyuridine-resistant 3T6 cell line (LU3-7) that over produces the enzyme and its mRNA about 50-fold and that regulates the expression of the thymidylate synthase gene in the same manner as the parental cell line. We have previously shown that the rate of synthesis of thymidylate synthase increases at least ninefold when the serum-stimulated cells traverse the S phase. Here we show, by Northern blot analysis, that thymidylate synthase mRNA increased 20- to 40-fold as cells progressed from resting to late S phase. About 85% of poly(A)+ thymidylate synthase mRNA was associated with polysomes at all times. The increase in thymidylate synthase poly(A)+ mRNA content was the result of an eightfold increase in the rate of production of this species, as shown by pulse-labeling studies. Pulse-chase analysis revealed that the half-life of thymidylate synthase poly(A)+ mRNA was similar in resting (9 h) and growing (7 h) cells. The rate of transcription of the thymidylate synthase gene, as determined in isolated nuclei, increased only by a factor of three to four during the S phase. Since the content of the message increased to a much greater extent than the rate of transcription of the gene, posttranscriptional controls must also play a role in regulating the content of thymidylate synthase mRNA under these conditions. Our results suggest that the cell may regulate the distribution of thymidylate synthase mRNA between a relatively stable poly(A)+ RNA species and a labile poly(A)- RNA species.


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