scholarly journals Desensitization of prostaglandin F2α-stimulated inositol phosphate generation in NIH-3T3 fibroblasts transformed by overexpression of normal c-Ha-ras-1, c-Ki-ras-2 and c-N-ras genes

1990 ◽  
Vol 267 (3) ◽  
pp. 809-813 ◽  
Author(s):  
F M Black ◽  
M J O Wakelam

The stimulation of inositol phosphate generation in control and ras-gene-transformed NIH-3T3 cells by prostaglandin F2 alpha (PGF2 alpha) was investigated. Compared with the control cells, a desensitization of the response was observed in cells transformed by the overexpression of N-, Ha-, or Ki-ras genes. This desensitization was without effect upon the concentration causing half-maximal effect (EC50), dissociation constant (Kd) or number of PGF2 alpha receptors. Inhibition of PG synthesis was without effect upon desensitization, demonstrating that the effect was not agonist-induced. Desensitization could be induced in NIH-3T3 cells by culturing under conditions where the cells were all in the exponential growth phase, or by a 12 h exposure to a C-kinase-activating phorbol ester. These results suggest that desensitization of certain agonist-induced inositol phospholipid responses in ras-transformed cells is a consequence of increased cell proliferation and associated amplification in C-kinase activity and is an indirect consequence of transformation by ras.

1986 ◽  
Vol 6 (5) ◽  
pp. 1843-1846 ◽  
Author(s):  
A G Papageorge ◽  
B M Willumsen ◽  
M Johnsen ◽  
H F Kung ◽  
D W Stacey ◽  
...  

Microinjection of monoclonal antibody Y13-259, which reacts with all known mammalian and yeast ras-encoded proteins, has previously been shown to prevent NIH 3T3 cells from entering the S phase (L. S. Mulcahy, M. R. Smith, and D. W. Stacey, Nature [London] 313:241-243, 1985). We have now found several transformation-competent mutant v-rasH genes whose protein products in transformed NIH 3T3 cells are not immunoprecipitated by this monoclonal antibody. These mutant proteins are, however, precipitated by a different anti-ras antibody. Each of these mutants lacks Met-72 of v-rasH. In contrast to the result for cells transformed by wild-type v-rasH, Y13-259 microinjection of NIH 3T3 cells transformed by these mutant ras genes did not prevent the cells from entering the S phase. These results imply that a transformation-competent ras gene can supply a normal essential function for NIH 3T3 cells. When the proteins encoded by the mutant ras genes were overproduced in Escherichia coli, several mutant proteins that lacked Met-72 failed to bind Y13-259 in a Western blot. However, a ras protein from a mutant lacking amino antibody, but a ras protein from a mutant lacking amino acids 72 to 84 did not. These results suggest that Y13-259 may bind to a higher ordered structure that has been restored in the mutant lacking amino acids 72 to 82.


1986 ◽  
Vol 6 (5) ◽  
pp. 1843-1846
Author(s):  
A G Papageorge ◽  
B M Willumsen ◽  
M Johnsen ◽  
H F Kung ◽  
D W Stacey ◽  
...  

Microinjection of monoclonal antibody Y13-259, which reacts with all known mammalian and yeast ras-encoded proteins, has previously been shown to prevent NIH 3T3 cells from entering the S phase (L. S. Mulcahy, M. R. Smith, and D. W. Stacey, Nature [London] 313:241-243, 1985). We have now found several transformation-competent mutant v-rasH genes whose protein products in transformed NIH 3T3 cells are not immunoprecipitated by this monoclonal antibody. These mutant proteins are, however, precipitated by a different anti-ras antibody. Each of these mutants lacks Met-72 of v-rasH. In contrast to the result for cells transformed by wild-type v-rasH, Y13-259 microinjection of NIH 3T3 cells transformed by these mutant ras genes did not prevent the cells from entering the S phase. These results imply that a transformation-competent ras gene can supply a normal essential function for NIH 3T3 cells. When the proteins encoded by the mutant ras genes were overproduced in Escherichia coli, several mutant proteins that lacked Met-72 failed to bind Y13-259 in a Western blot. However, a ras protein from a mutant lacking amino antibody, but a ras protein from a mutant lacking amino acids 72 to 84 did not. These results suggest that Y13-259 may bind to a higher ordered structure that has been restored in the mutant lacking amino acids 72 to 82.


1988 ◽  
Vol 8 (2) ◽  
pp. 786-793
Author(s):  
J Leon ◽  
H Kamino ◽  
J J Steinberg ◽  
A Pellicer

The involvement of the ras oncogenes in tumorigenesis was investigated in keratoacanthomas, which are benign and self-regressing skin tumors, both in humans and in a corresponding animal model system. Keratoacanthomas were induced on rabbit ears by repeated applications of 7,12-dimethylbenz(a)anthracene. About 60% of the tumor DNAs produced transformed foci after transfection into NIH 3T3 cells, and in all of them the transforming gene was identified as H-ras by Southern and Northern (RNA) hybridization. Immunoprecipitation experiments suggested that the transforming rabbit H-ras protein carried a mutation in codon 61. In addition, an activated H-ras gene was detected in a human keratoacanthoma by using a nude mouse tumorigenesis assay after transfection of tumor DNA into NIH 3T3 cells. This is the first report of ras activation in a benign human tumor. The transforming human H-ras gene showed a point mutation in codon 61 that would result in leucine instead of the glutamine present in the normal gene product. The finding of ras activation in tumors that are not only benign but also self-regressing indicates that activated ras genes are not sufficient to maintain a neoplastic phenotype, although they likely play a role in early stages of tumorigenesis.


1988 ◽  
Vol 8 (2) ◽  
pp. 786-793 ◽  
Author(s):  
J Leon ◽  
H Kamino ◽  
J J Steinberg ◽  
A Pellicer

The involvement of the ras oncogenes in tumorigenesis was investigated in keratoacanthomas, which are benign and self-regressing skin tumors, both in humans and in a corresponding animal model system. Keratoacanthomas were induced on rabbit ears by repeated applications of 7,12-dimethylbenz(a)anthracene. About 60% of the tumor DNAs produced transformed foci after transfection into NIH 3T3 cells, and in all of them the transforming gene was identified as H-ras by Southern and Northern (RNA) hybridization. Immunoprecipitation experiments suggested that the transforming rabbit H-ras protein carried a mutation in codon 61. In addition, an activated H-ras gene was detected in a human keratoacanthoma by using a nude mouse tumorigenesis assay after transfection of tumor DNA into NIH 3T3 cells. This is the first report of ras activation in a benign human tumor. The transforming human H-ras gene showed a point mutation in codon 61 that would result in leucine instead of the glutamine present in the normal gene product. The finding of ras activation in tumors that are not only benign but also self-regressing indicates that activated ras genes are not sufficient to maintain a neoplastic phenotype, although they likely play a role in early stages of tumorigenesis.


2019 ◽  
Vol 34 (8) ◽  
pp. 1536-1550 ◽  
Author(s):  
A Christine Kauerhof ◽  
Nour Nicolas ◽  
Sudhanshu Bhushan ◽  
Eva Wahle ◽  
Kate A Loveland ◽  
...  

Abstract STUDY QUESTION Does activin A contribute to testicular fibrosis under inflammatory conditions? SUMMARY ANSWER Our results show that activin A and key fibrotic proteins are increased in human testicular biopsies with leukocytic infiltrates and impaired spermatogenesis and in murine experimental autoimmune orchitis (EAO) and that activin A stimulates fibrotic responses in peritubular cells (PTCs) and NIH 3T3 fibroblasts. WHAT IS KNOWN ALREADY Fibrosis is a feature of EAO. Activin A, a regulator of fibrosis, was increased in testes of mice with EAO and its expression correlated with severity of the disease. STUDY DESIGN, SIZE, DURATION This is a cross-sectional and longitudinal study of adult mice immunized with testicular homogenate (TH) in adjuvant to induce EAO, collected at 30 (n = 6), 50 (n = 6) and 80 (n = 5) days after first immunization. Age-matched mice injected with adjuvant alone (n = 14) and untreated mice (n = 15) were included as controls. TH-immunized mice with elevated endogenous follistatin, injected with a non-replicative recombinant adeno-associated viral vector carrying a gene cassette of follistatin (rAAV-FST315; n = 3) or vector with an empty cassette (empty vector controls; n = 2) 30 days prior to the first immunization, as well as appropriate adjuvant (n = 2) and untreated (n = 2) controls, were also examined. Human testicular biopsies showing focal inflammatory lesions associated with impaired spermatogenesis (n = 7) were included. Biopsies showing intact spermatogenesis without inflammation, from obstructive azoospermia patients, served as controls (n = 7). Mouse primary PTC and NIH 3T3 fibroblasts were stimulated with activin A and follistatin 288 (FST288) to investigate the effect of activin A on the expression of fibrotic markers. Production of activin A by mouse primary Sertoli cells (SCs) was also investigated. PARTICIPANTS/MATERIALS, SETTING, METHODS Testicular RNA and protein extracts collected from mice at days 30, 50 and 80 after first immunization were used for analysis of fibrotic marker genes and proteins, respectively. Total collagen was assessed by hydroxyproline assay and fibronectin; collagen I, III and IV, α-smooth muscle actin (α-SMA) expression and phosphorylation of suppressor of mothers against decapentaplegic (SMAD) family member 2 were measured by western blot. Immunofluorescence was used to detect fibronectin. Fibronectin (Fn), αSMA (Acta2), collagen I (Col1a2), III (Col3a1) and IV (Col4a1) mRNA in PTC and NIH 3T3 cells treated with activin A and/or FST288 were measured by quantitative RT-PCR (qRT-PCR). Activin A in SC following tumour necrosis factor (TNF) or FST288 stimulation was measured by ELISA. Human testicular biopsies were analysed by qRT-PCR for PTPRC (CD45) and activin A (INHBA), hydroxyproline assay and immunofluorescence. MAIN RESULTS AND THE ROLE OF CHANCE Production of activin A by SC was stimulated by 25 and 50 ng/ml TNF (P < 0.01, P < 0.001, respectively) as compared to untreated cells. INHBA mRNA was increased in human testicular biopsies with leukocytic infiltrates and impaired spermatogenesis, compared with control biopsies (P < 0.05), accompanied by increased total collagen (P < 0.01) and fibronectin deposition. Total testicular collagen (P < 0.0001) and fibronectin protein expression (P < 0.05) were also increased in EAO, and fibronectin expression was correlated with the severity of the disease (r = 0.9028). In animals pre-treated with rAAV-FST315 prior to immunization with TH, protein expression of fibronectin was comparable to control. Stimulation of PTC and NIH 3T3 cells with activin A increased fibronectin mRNA (P < 0.05) and the production of collagen I (P < 0.001; P < 0.01) and fibronectin (P < 0.05). Moreover, activin A also increased collagen IV mRNA (P < 0.05) in PTC, while αSMA mRNA (P < 0.01) and protein (P < 0.0001) were significantly increased by activin A in NIH 3T3 cells. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION A limited number of human testicular specimens was available for the study. Part of the study was performed in vitro, including NIH 3T3 cells as a surrogate for testicular fibroblasts. WIDER IMPLICATIONS OF THE FINDINGS Resident fibroblasts and PTC may contribute to the progression of testicular fibrosis following inflammation, and activin A is implicated as a key mediator of this process. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the National Health and Medical Research Council of Australia, the Victorian Government’s Operational Infrastructure Support Program and the International Research Training Group between Justus Liebig University (Giessen) and Monash University (Melbourne) (GRK 1871/1–2) on `Molecular pathogenesis on male reproductive disorders’ funded by the Deutsche Forschungsgemeinschaft and Monash University. The authors declare no competing financial interests.


2006 ◽  
Vol 398 (2) ◽  
pp. 215-224 ◽  
Author(s):  
Sara Sánchez-Molina ◽  
José Luis Oliva ◽  
Susana García-Vargas ◽  
Ester Valls ◽  
José M. Rojas ◽  
...  

The CBP [CREB (cAMP-response-element-binding protein)-binding protein]/p300 acetyltransferases function as transcriptional co-activators and play critical roles in cell differentiation and proliferation. Accumulating evidence shows that alterations of the CBP/p300 protein levels are linked to human tumours. In the present study, we show that the levels of the CBP/p300 co-activators are decreased dramatically by continuous PDGF (platelet-derived growth factor) and Ras signalling pathway activation in NIH 3T3 fibroblasts. This effect occurs by reducing the expression levels of the CBP/p300 genes. In addition, CBP and p300 are degraded by the 26 S proteasome pathway leading to an overall decrease in the levels of the CBP/p300 proteins. Furthermore, we provide evidence that Mdm2 (murine double minute 2), in the presence of active H-Ras or N-Ras, induces CBP/p300 degradation in NIH 3T3 cells. These findings support a novel mechanism for modulating other signalling transduction pathways that require these common co-activators.


1993 ◽  
Vol 13 (3) ◽  
pp. 1824-1835 ◽  
Author(s):  
A Aoyama ◽  
E Fröhli ◽  
R Schäfer ◽  
R Klemenz

alpha B-crystallin, a major soluble protein of vertebrate eye lenses, is a small heat shock protein which transiently accumulates in response to heat shock and other kinds of stress in mouse NIH 3T3 fibroblasts. Ectopic expression of an alpha B-crystallin cDNA clone renders NIH 3T3 cells thermoresistant. alpha B-crystallin accumulates in response to the synthetic glucocorticoid hormone dexamethasone. Dexamethasone-treated NIH 3T3 cells become thermoresistant to the same extent as they accumulate alpha B-crystallin. A cell clone in which alpha B-crystallin is superinduced upon heat shock acquires augmented thermotolerance. Expression of the ras oncogene causes a rapid but transient accumulation of alpha B-crystallin within 1 day. Later, sustained ras oncogene expression suppresses the dexamethasone-mediated alpha B-crystallin accumulation. Thus, oncogenic transformation triggered by the ras oncogene interferes with hormone-mediated accumulation of alpha B-crystallin and concomitant acquisition of thermoresistance. Other known heat shock proteins do not accumulate in response to ectopic alpha B-crystallin expression or to dexamethasone treatment. These results indicate that alpha B-crystallin can protect NIH 3T3 fibroblasts from thermal shock.


1987 ◽  
Vol 7 (7) ◽  
pp. 2512-2520 ◽  
Author(s):  
R D Owen ◽  
M C Ostrowski

Hormone treatment of NIH 3T3 cells that contain recombinant fusions between the mouse mammary virus long terminal repeat and the v-ras gene of Harvey murine sarcoma virus results in conditional expression of the ras p21 gene product. Levels of ras mRNA and p21 are maximal after 2 to 4 h of hormone treatment. Analysis of cellular RNA by Northern blotting and nuclease S1 protection assays indicates that the expression of two cellular RNA species increases with kinetics similar to v-ras: v-sis-related RNA and retrovirus-related VL30 RNA. Run-on transcription in isolated nuclei shows that the increase in v-sis-related RNA is not dependent on transcription and therefore must arise by a post-transcriptional mechanism. The increase in VL30 expression is a transcriptional effect. Hormone treatment of normal NIH 3T3 cells has no effect on the expression of these DNA sequences. These results suggest that v-ras stimulation of autocrine factors may play a role in transformation of cells by this gene and also suggest a reverse genetic strategy to determine the nucleic acid sequences and cellular factors involved in the regulation of gene expression that is observed.


1987 ◽  
Vol 7 (7) ◽  
pp. 2512-2520
Author(s):  
R D Owen ◽  
M C Ostrowski

Hormone treatment of NIH 3T3 cells that contain recombinant fusions between the mouse mammary virus long terminal repeat and the v-ras gene of Harvey murine sarcoma virus results in conditional expression of the ras p21 gene product. Levels of ras mRNA and p21 are maximal after 2 to 4 h of hormone treatment. Analysis of cellular RNA by Northern blotting and nuclease S1 protection assays indicates that the expression of two cellular RNA species increases with kinetics similar to v-ras: v-sis-related RNA and retrovirus-related VL30 RNA. Run-on transcription in isolated nuclei shows that the increase in v-sis-related RNA is not dependent on transcription and therefore must arise by a post-transcriptional mechanism. The increase in VL30 expression is a transcriptional effect. Hormone treatment of normal NIH 3T3 cells has no effect on the expression of these DNA sequences. These results suggest that v-ras stimulation of autocrine factors may play a role in transformation of cells by this gene and also suggest a reverse genetic strategy to determine the nucleic acid sequences and cellular factors involved in the regulation of gene expression that is observed.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3370-3370
Author(s):  
Wenjing Tao ◽  
Hui Lin ◽  
Tong Sun ◽  
Ajoy K. Samanta ◽  
Ralph B. Arlinghaus

Abstract Bcr-Abl is a leukemia-inducing protein, which causes oncogenic transformation of myeloid progenitors in Philadelphia chromosome (Ph)-positive chronic myeloid leukemia (CML) and lymphoid progenitors in Ph+ acute lymphoid leukemia (ALL). Oncogenic transformation of hematopoietic cells by the Bcr-Abl oncoprotein directly involves the activation Jak2 tyrosine kinase and the Stat5 transcription factor. Both proteins are normally linked to the IL-3/GM-CSF receptors for growth and survival. Since fibroblastic cells are not targets of BCR-ABL induced oncogenesis, we determined whether forced expression of the IL-3 receptor would allow oncogenic transformation of NIH 3T3 fibroblasts known to be resistant to transformation by BCR-ABL. NIH 3T3 cells transduced with the human IL-3 receptor a and b chains were highly susceptible to oncogenic transformation by expression of BCR-ABL. Forced expression of both receptor chains but not either one alone allowed efficient foci formation of NIH 3T3 cells expressing BCR-ABL, and these cells formed colonies in soft agar whereas BCR-ABL positive NIH 3T3 cells lacking IL-3 receptor expression did not. The Bcr-Abl kinase inhibitor imatinib mesylate (1 mM) and the Jak kinase inhibitor AG490 (10 mM) strongly inhibited agar colony formation. A small molecule inhibitor of Jak2 kinase, 1,2,3,4,5,6-hexabromocyclohexane reported to be specific for Jak2 (Sandberg et al. J. Med. Chem, 2005)-significantly reduced the phosphorylation of Gab2 at the YxxM motif, which is needed for activation of the PI-3 kinase and Akt, two proteins that are part of the Bcr-Abl/Jak2 Network (Samanta et al. Cancer Res, 2006). These findings indicate that Bcr-Abl oncoprotein requires the IL-3 receptor/Jak2/Stat5 pathways for oncogenic transformation of NIH 3T3 fibroblasts, and may explain partially why Bcr-Abl oncogenesis is restricted to hematopoietic malignancies. Furthermore, this cell system in fibroblastic and other cell lineages will provide a model to probe the detailed steps that require IL-3 receptor and Jak2 for Bcr-Abl induced leukemia.


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