IKK/NF-κB signaling pathway inhibits cell-cycle progression by a novel Rb-independent suppression system for E2F transcription factors

ABSTRACT Independent of its antiapoptotic function, Bcl-2 can, through an undetermined mechanism, retard entry into the cell cycle. Cell cycle progression requires the phosphorylation by cyclin-dependent kinases (Cdks) of retinoblastoma protein (pRB) family members to free E2F transcription factors. We have explored whether retarded cycle entry is mediated by the Cdk inhibitor p27 or the pRB family. In quiescent fibroblasts, enforced Bcl-2 expression elevated levels of both p27 and the pRB relative p130. Bcl-2 still slowed G1 progression in cells deficient in pRB but not in those lacking p27 or p130. Hence, pRB is not required, but both p27 and p130 are essential mediators. The ability of p130 to form repressive complexes with E2F4 is implicated, because the retardation by Bcl-2 was accentuated by coexpressed E2F4. A plausible relevant target of p130/E2F4 is the E2F1 gene, because Bcl-2 expression delayed E2F1 accumulation during G1 progression and overexpression of E2F1 overrode the Bcl-2 inhibition. Hence, Bcl-2 appears to retard cell cycle entry by increasing p27 and p130 levels and maintaining repressive complexes of p130 with E2F4, perhaps to delay E2F1 expression.

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Post-Transcriptional Regulation of E2F Transcription Factors: Fine-Tuning DNA Repair, Cell Cycle Progression and Survival in Development & Disease

DNA Repair ◽

10.5772/22159 ◽

2011 ◽

Author(s):

Lina Dagnino ◽

Randeep Kaur ◽

David Judah

Keyword(s):

Cell Cycle ◽

Dna Repair ◽

Transcriptional Regulation ◽

Transcription Factors ◽

Cell Cycle Progression ◽

Fine Tuning ◽

Cycle Progression ◽

E2f Transcription Factors ◽

Post Transcriptional Regulation

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Spirulina Crude Protein Promotes the Migration and Proliferation in IEC-6 Cells by Activating EGFR/MAPK Signaling Pathway

Marine Drugs ◽

10.3390/md17040205 ◽

2019 ◽

Vol 17 (4) ◽

pp. 205

Author(s):

Su-Jin Jeong ◽

Jeong-Wook Choi ◽

Min-Kyeong Lee ◽

Youn-Hee Choi ◽

Taek-Jeong Nam

Keyword(s):

Cell Cycle ◽

Epithelial Cells ◽

Signaling Pathway ◽

Crude Protein ◽

Cell Cycle Progression ◽

Intestinal Epithelial Cells ◽

Mapk Signaling ◽

S Phase ◽

Intestinal Epithelial ◽

Cycle Progression

Spirulina is a type of filamentous blue-green microalgae known to be rich in nutrients and to have pharmacological effects, but the effect of spirulina on the small intestine epithelium is not well understood. Therefore, this study aims to investigate the proliferative effects of spirulina crude protein (SPCP) on a rat intestinal epithelial cells IEC-6 to elucidate the mechanisms underlying its effect. First, the results of wound-healing and cell viability assays demonstrated that SPCP promoted migration and proliferation in a dose-dependent manner. Subsequently, when the mechanisms of migration and proliferation promotion by SPCP were confirmed, we found that the epidermal growth factor receptor (EGFR) and mitogen-activated protein (MAPK) signaling pathways were activated by phosphorylation. Cell cycle progression from G0/G1 to S phase was also promoted by SPCP through upregulation of the expression levels of cyclins and cyclin-dependent kinases (Cdks), which regulate cell cycle progression to the S phase. Meanwhile, the expression of cyclin-dependent kinase inhibitors (CKIs), such as p21 and p27, decreased with SPCP. In conclusion, our results indicate that activation of EGFR and its downstream signaling pathway by SPCP treatment regulates cell cycle progression. Therefore, these results contribute to the research on the molecular mechanism for SPCP promoting the migration and proliferation of rat intestinal epithelial cells.

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The Role of EGFR/PI3K/Akt/cyclinD1 Signaling Pathway in Acquired Middle Ear Cholesteatoma

Mediators of Inflammation ◽

10.1155/2013/651207 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 16

Author(s):

Wei Liu ◽

Hongmiao Ren ◽

Jihao Ren ◽

Tuanfang Yin ◽

Bing Hu ◽

...

Keyword(s):

Cell Cycle ◽

Cell Proliferation ◽

Signaling Pathways ◽

Signaling Pathway ◽

External Auditory Canal ◽

Cell Cycle Progression ◽

Critical Role ◽

Immunohistochemical Method ◽

Cycle Progression ◽

Middle Ear Cholesteatoma

Cholesteatoma is a benign keratinizing and hyper proliferative squamous epithelial lesion of the temporal bone. Epidermal growth factor (EGF) is one of the most important cytokines which has been shown to play a critical role in cholesteatoma. In this investigation, we studied the effects of EGF on the proliferation of keratinocytes and EGF-mediated signaling pathways underlying the pathogenesis of cholesteatoma. We examined the expressions of phosphorylated EGF receptor (p-EGFR), phosphorylated Akt (p-Akt), cyclinD1, and proliferating cell nuclear antigen (PCNA) in 40 cholesteatoma samples and 20 samples of normal external auditory canal (EAC) epithelium by immunohistochemical method. Furthermore,in vitrostudies were performed to investigate EGF-induced downstream signaling pathways in primary external auditory canal keratinocytes (EACKs). The expressions of p-EGFR, p-Akt, cyclinD1, and PCNA in cholesteatoma epithelium were significantly increased when compared with those of control subjects. We also demonstrated that EGF led to the activation of the EGFR/PI3K/Akt/cyclinD1 signaling pathway, which played a critical role in EGF-induced cell proliferation and cell cycle progression of EACKs. Both EGFR inhibitor AG1478 and PI3K inhibitor wortmannin inhibited the EGF-induced EGFR/PI3K/Akt/cyclinD1 signaling pathway concomitantly with inhibition of cell proliferation and cell cycle progression of EACKs. Taken together, our data suggest that the EGFR/PI3K/Akt/cyclinD1 signaling pathway is active in cholesteatoma and may play a crucial role in cholesteatoma epithelial hyper-proliferation. This study will facilitate the development of potential therapeutic targets for intratympanic drug therapy for cholesteatoma.

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Disruption of SHH signaling cascade by SBE attenuates lung cancer progression and sensitizes DDP treatment

Scientific Reports ◽

10.1038/s41598-017-02063-x ◽

2017 ◽

Vol 7 (1) ◽

Cited By ~ 8

Author(s):

Jing Du ◽

Weiwei Chen ◽

Lijuan Yang ◽

Juanjuan Dai ◽

Jiwei Guo ◽

...

Keyword(s):

Lung Cancer ◽

Cell Cycle ◽

Cancer Cells ◽

Signaling Pathway ◽

Cell Cycle Progression ◽

Lung Cancer Cells ◽

Human Lung Cancer ◽

Cycle Progression ◽

Shh Signaling ◽

Shh Pathway

Abstract Deregulated Sonic Hedgehog (SHH) pathway facilitates the initiation, progression, and metastasis of Non-small cell lung cancer (NSCLC), confers drug resistance and renders a therapeutic interference option to lung cancer patients with poor prognosis. In this study, we screened and evaluated the specificity of a Chinese herb Scutellariabarbata D. Don extraction (SBE) in repressing SHH signaling pathway to block NSCLC progression. Our study confirmed that aberrant activation of the SHH signal pathway conferred more proliferative and invasive phenotypes to human lung cancer cells. This study revealed that SBE specifically repressed SHH signaling pathway to interfere the SHH-mediated NSCLC progression and metastasis via arresting cell cycle progression. We also found that SBE significantly sensitized lung cancer cells to chemotherapeutic agent DDP via repressing SHH components in vitro and in vivo. Mechanistic investigations indicated that SBE transcriptionally and specifically downregulated SMO and consequently attenuated the activities of GLI1 and its downstream targets in SHH signaling pathway, which interacted with cell cycle checkpoint enzymes to arrest cell cycle progression and lead to cellular growth inhibition and migration blockade. Collectively, our results suggest SBE as a novel drug candidate for NSCLC which specifically and sensitively targets SHH signaling pathway.

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S1271 Plantago Ovata Husk Regulates Cell Cycle Progression and Wnt Signaling Pathway, Crucial Elements Implicated in Colorectal Carcinogenesis

Gastroenterology ◽

10.1016/s0016-5085(09)61020-9 ◽

2009 ◽

Vol 136 (5) ◽

pp. A-226

Author(s):

Vanessa R. Sapoznik ◽

Michael N. Grzybowski ◽

Rosa M. Xicola ◽

Brian J. Doyle ◽

Jessica Grzybowski ◽

...

Keyword(s):

Cell Cycle ◽

Wnt Signaling ◽

Signaling Pathway ◽

Cell Cycle Progression ◽

Wnt Signaling Pathway ◽

Colorectal Carcinogenesis ◽

Plantago Ovata ◽

Cycle Progression

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Fstl1 Promotes Glioma Growth Through the BMP4/Smad1/5/8 Signaling Pathway

Cellular Physiology and Biochemistry ◽

10.1159/000485759 ◽

2017 ◽

Vol 44 (4) ◽

pp. 1616-1628 ◽

Cited By ~ 7

Author(s):

Xin Jin ◽

Er Nie ◽

Xu Zhou ◽

Ailiang Zeng ◽

Tianfu Yu ◽

...

Keyword(s):

Cell Cycle ◽

Cell Proliferation ◽

Signaling Pathway ◽

Colony Formation ◽

Cell Cycle Progression ◽

Malignant Gliomas ◽

Treatment Strategies ◽

Cycle Progression ◽

Glioma Growth

Background: Gliomas result in the highest morbidity and mortality rates of intracranial primary central nervous system tumors because of their aggressive growth characteristics and high postoperative recurrence. They are characterized by genetic instability, intratumoral histopathological variability and unpredictable clinical behavior in patients. Proliferation is a key aspect of the clinical progression of malignant gliomas, complicating complete surgical resection and enabling tumor regrowth and further proliferation of the surviving tumor cells. Methods: The expression of Fstl1 was detected by western blotting and qRT-PCR. We used cell proliferation and colony formation assays to measure proliferation. Then, flow cytometry was used to analyze cell cycle progression. The expression of Fstl1, p-Smad1/5/8 and p21 in GBM tissue sections was evaluated using immunohistochemical staining. Furthermore, we used coimmunoprecipitation (Co-IP) and immunoprecipitation to validate the relationship between Fstl1, BMP4 and BMPR2. Finally, we used orthotopic xenograft studies to measure the growth of tumors in vivo. Results: We found that follistatin-like 1 (Fstl1) was upregulated in high-grade glioma specimens and that its levels correlated with poor prognosis. Fstl1 upregulation increased cell proliferation, colony formation and cell cycle progression, while its knockdown inhibited these processes. Moreover, Fstl1 interacted with bone morphogenetic protein (BMP) 4, but not BMP receptor (BMPR) 2, and competitively inhibited their association. Furthermore, Fstl1 overexpression suppressed the activation of the BMP4/Smad1/5/8 signaling pathway, while BMP4 overexpression reversed this effect. Conclusion: Our study demonstrated that Fstl1 promoted glioma growth through the BMP4/Smad1/5/8 signaling pathway, and these findings suggest potential new glioblastoma treatment strategies.

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