Pituitary tumors and immortalized cell lines generated by cre-inducible expression of SV40 T antigen

Endocrinology ◽  
2021 ◽  
Author(s):  
Alexandre Z Daly ◽  
Amanda H Mortensen ◽  
Hironori Bando ◽  
Sally A Camper

Abstract Targeted oncogenesis is the process of driving tumor formation by engineering transgenic mice that express an oncogene under the control of a cell-type specific promoter. Such tumors can be adapted to cell culture, providing immortalized cell lines. To make it feasible to follow the process of tumorigenesis and increase the opportunity for generating cell lines, we developed a mouse strain that expresses SV40 T antigens in response to cre-recombinase. Using CRISPR/Cas9 we inserted a cassette with coding sequences for SV40 T antigens and an internal ribosome entry site with green fluorescent protein cassette (IRES-GFP) into the Rosa26 locus, downstream from a stop sequence flanked by loxP sites: Rosa26LSL-SV40-GFP. These mice were mated with previously established Prop1-cre and Tshb-cre transgenic lines. Both the Rosa26LSL-SV40-GFP/+; Prop1-cre and Rosa26LSL-SV40-GFP/+; Tshb-cre mice developed fully penetrant dwarfism and large tumors by 4 weeks. Tumors from both of these mouse lines were adapted to growth in cell culture. We have established a progenitor-like cell line (PIT-P1) that expresses Sox2 and Pitx1, and a thyrotrope-like cell line (PIT-T1) that expresses Pou1f1 and Cga. These studies demonstrate the utility of the novel, Rosa26LSL-SV40-GFP mouse line for reliable targeted oncogenesis and development of unique cell lines.

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Amanda Helen Mortensen ◽  
Alexandre Daly ◽  
Lindsey Anne Dudley ◽  
Sally Ann Camper

Abstract Pituitary and hypothalamic cell lines have been developed by targeted oncogenesis. This involved using cell-specific transcriptional regulatory sequences to drive expression of large and small SV40 T-antigens in transgenic mice. Invariably, tumors develop in some of the mice, and the cells in these tumors can sometimes be adapted to grow in culture into stable, immortalized cell lines that maintain some of the features of differentiated cells. Cell lines that represent pre-gonadotropes (αT3-1), gonadotropes (LβT2), precursors to the POU1F1 lineage (GHFT1, Pit1-zero), differentiated cells of the POU1F1 lineage (Pit1-triple, TaT1, and Pit1-PRL), and GnRH neurons (GT1-1) have been made by this approach. Tumors often develop early and cause infertility or death. To increase the opportunity for generating cell lines and to make it feasible to follow the process of tumorigenesis, we developed a mouse strain that expresses SV40 T-antigens in response to cre-recombinase. Using CRISPR/Cas9 we inserted an 8 kb cassette with coding sequences for SV40 T-antigens and IRES-GFP into the Rosa26 locus, downstream from a stop sequence flanked by loxP sites: Rosa26LSL-SV40-GFP. 30% of the progeny born from hybrid zygotes injected with template DNA, CRISPR/Cas9, and sgRNA had correctly targeted the Rosa26 locus. These mice were mated with previously established Prop1-cre and Tshb-cre transgenic lines. The majority of Rosa26LSL-SV40-GFP/+; Prop1-cre and Rosa26LSL-SV40-GFP/+; Tshb-cre mice developed dwarfism and large tumors by 4 wks. The pituitaries of Rosa26LSL-SV40-GFP/+; Tshb-cre mice appear grossly normal at birth, but they are enlarged and showing evidence of increased vascularization by 2 wks. Flow-sorted GFP-positive cells from Rosa26LSL-SV40-GFP/+; Prop1-cre and Rosa26LSL-SV40-GFP/+; Tshb-cre mice express Prop1 and TSH, respectively. Tumors from Rosa26LSL-SV40-GFP/+; Tshb-cre mice were adapted to growth in cell culture. We have established a thyrotrope-like cell line that expresses Cga and Pou1f1. These studies demonstrate the utility of the novel, Rosa26LSL-SV40-GFP mouse line for reliable targeted oncogenesis and development of unique cell lines. The authors have nothing to disclose.


2001 ◽  
Vol 171 (1) ◽  
pp. 45-55 ◽  
Author(s):  
TM Thway ◽  
CM Clay ◽  
JK Maher ◽  
DK Reed ◽  
KJ McDowell ◽  
...  

Immortalized cell lines have many potential experimental applications including the analysis of molecular mechanisms underlying cell-specific gene expression. We have utilized a recombinant retrovirus encoding the simian virus-40 (SV-40) large T antigen to construct several immortalized cell lines of equine chorionic girdle cell lineage - the progenitor cells that differentiate into the equine chorionic gonadotropin (eCG) producing endometrial cups. Morphologically, the immortalized cell lines appear similar to normal chorionic girdle cells. Derivation of the immortalized cell lines from a chorionic girdle cell lineage was verified by immunological detection of cell-surface antigens specific to equine invasive trophoblasts. The cell lines differed, however, from mature chorionic girdle cells or endometrial cup cells in that they did not produce eCG and did express MHC class I molecules. Thus, these cell lines appear to have been arrested at a stage of development prior to final differentiation into endometrial cup cells. It was also determined that some of these cell lines as well as endometrial cups express the estrogen receptor-related receptor beta gene, but not the glial cell missing gene (GCMa) both of which are expressed in the murine and human placenta. Among these cell lines, three (eCG 50.5, 100.6 and 500.1) express eCG alpha mRNA. Since regulation of eCG alpha subunit gene is largely unknown, we investigated the signal transduction pathways regulating the eCG alpha subunit gene. Both activators of protein kinase A (PKA) and protein kinase C (PKC) induced the expression of eCG alpha subunit expression 3.2 (P<0.05)- and 1.9 (P<0.05)-fold respectively, in the eCG 500.1 cell line. However, activation of these pathways failed to induce eCG beta subunit expression. In conclusion, lines of equine trophoblast cells have been immortalized that display markers characteristic of those with the equine chorionic girdle and endometrial cup cell lineage. A subset of these cells expresses the eCG alpha subunit gene which is responsive to activators of the PKA and PKC signal transduction pathways.


2021 ◽  
pp. 297-303
Author(s):  
V. L. Manin ◽  
I. V. Vologina ◽  
Ye. A. Trofimova

Preparation of immortalized cell lines obtained from organs and tissues of farm animals is an essential area of biotechnology. The paper presents results of continuous (immortalized) cell line preparation from a primary trypsinized cell culture of an adult rabbit kidney. Cytomorphologic analysis and karyotyping were performed during the process of subcultivation in the cell culture at passages 1, 3, 24, 31, 38, 56, 66, 75, 86, 101. Dynamics of spontaneous continuous cell line formation during long-term serial passaging was examined using standard nutrient media and fetal serum. Contrary to the known cell lines of rabbit origin (Oryctolagus cuniculus L.), immortalization was not accompanied with enhanced cell production and cell size reduction. The prepared continuous cell line in its adhesive phase was up to 200 µm in size and its productivity was about 7,000 cells/cm2. Significant differences (compared to the known cell lines) in the karyotype were detected during passaging. The formed genotype was found to be near-tetrapioid when the CCL cultural properties were stabilized at passages 66–101. The known cell lines – rabbit kidney (RK-13) and rabbit cornea (SIRC) – can be characterized as pseudotriploid basing on their karyotype. This culture demonstrated low sensitivity to viruses – causative agents of rabbit diseases and sensitivity to heterologous porcine and bovine viruses.


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.


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