Knockdown of p53 combined with expression of the catalytic subunit of telomerase is sufficient to immortalize primary human ovarian surface epithelial cells
Authors: Gordon B Mills
Robert C Bast Jr
Daniel G Rosen
Justin A Colacino
Chenyi Zhou
Imelda Mercado-Uribe
Gong Yang
Jinsong Liu
Journal: Carcinogenesis (2007)
Discipline: CLINICAL MEDICINE
Keywords: Ovarian cancer; human ovarian surface epithelial cells; immortalization; p53; telomerase
Affiliations: Department of Pathology, The University of Texas M D Anderson Cancer Center, Houston, TX 77030, USA.

Abstract:  Ovarian cancer is developed from a single layer of thin epithelial cells covering the surface of ovary, named human ovarian surface epithelial cells. Like all primary human cells, human ovarian surface epithelial cells have a finite life span and will go into senescence and eventually die when cultured in vitro. Immortalized human ovarian surface epithelial cells will provide an important model system with which to study ovarian cancer initiation and progression. Here, we show that silencing p53 expression with retrovirus-mediated small interfering RNA can delay the senescence and extend cell passage number, but is not sufficient to immortalize normal ovarian surface epithelial cells. Introduction of the catalytic subunit of telomerase is similarly insufficient to achieve immortalization. However, concurrent disruption of p53 expression with small interfering RNA retroviral constructs and ectopic expression of the catalytic subunit of telomerase was sufficient to induce cellular immortalization in 3 of 3 human ovarian surface epithelial cell cultures tested. The immortalization is associated with increased telomerase activity and telomere length, and attenuated response of cell-cycle regulatory proteins to irradiation. The resultant immortal cells continued to express the same specific cytokeratins 8 and 18 as parental cells did, indicating that the epithelial characters are still maintained in the immortal cells. In addition, the immortalized cells are non-tumorigenic and nearly diploid, which is in constrast with one immortalized by SV40 T/t antigens and hTERT. As both p53 pathway dysfunction and activation of telomerase are commonly present in human ovarian cancer, these immortal cells provide an authetic cell model system for the study of the human ovarian cancer initiation, progression, differentiation and chemoprevention. 

Retracted: No

PubPeer comments:
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 The first two lanes of beta-actin in **Fig. 6** look similar to those in **Fig. 3 C** : ![file] , 
 Other figures from the *Oncogene* paper seem to derive from the respective figures in the *Carcinogenesis* paper: **Fig. 3 f** (Oncogene, 2007) *versus* **Fig. 4 A** (Carcinogenesis): - The **marker lane** of the TRAP assays is identical in both papers; - In addition, there is a **downward shift** for the expected position of the amplicons in Fig. 3 f, not showing the internal controls at 36 bp; - A horizontal flip of the **negative control lane** could link both images; - The **T137 lanes** expressing the corresponding tumor suppressor siRNAs look identical (fainter in Fig. 3 f). . ![file] . **Fig. 5 b** (Oncogene, 2007) *versus* **Fig. 7 A** (Carcinogenesis): - All **tumour volumes** (T29H) are identical; - Carcinogenesis: from u201c*four nude mice*u201d; - Oncogene: u201c*We repeated the assays twice and obtained the same results (Figure 5a and b).*u201d . ![file] . , 
 Please see the folllowing link from Oncogene for explantion: https: www.nature.com articles s41388-020-1294-4 ,