scholarly journals The Mechanism of Raf Activation through Dimerization

2021 ◽  
Author(s):  
Mingzhen Zhang ◽  
Ryan Colin Maloney ◽  
Hyunbum Jang ◽  
Ruth Nussinov

Raf, a threonine/serine kinase in the Raf/MEK/ERK pathway, regulates cell proliferation. Raf’s full activation requires dimerization. Aberrant activation through dimerization is an important therapeutic target. Despite its clinical importance, fundamental...

2020 ◽  
Vol 19 ◽  
pp. 153303382098078
Author(s):  
Yanjuan Guo ◽  
Nannan Zhao ◽  
Jianli Zhou ◽  
Jianxin Dong ◽  
Xing Wang

Objective: The present study aimed to explore the function of sirtuin 2 (SIRT2) on cell proliferation, apoptosis, rat sarcoma virus (RAS)/ extracellular signal-regulated kinase (ERK) pathway in endometrial cancer (EC). Methods: SIRT2 expression in human EC cell lines and human endometrial (uterine) epithelial cell (HEEC) line was assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot. SIRT2 knock-down and control knock-down plasmids were transfected into HEC1A cells, respectively; SIRT2 overexpression and control overexpression plasmids were transfected into Ishikawa cells, respectively. After transfection, SIRT2, HRas proto-oncogene, GTPase (HRAS) expressions were evaluated by RT-qPCR and western blot. ERK and phosphorylated ERK (pERK) expressions were evaluated by western blot. Meanwhile, cell proliferation and cell apoptosis were measured. Results: Compared to normal HEEC cell line, SIRT2 mRNA and protein expressions were increased in most human EC cell lines (including HEC1A, RL952 and AN3CA), while were similar in Ishikawa cell line. In HEC1A cells, SIRT2 knock-down decreased cell proliferation but increased apoptosis. In Ishikawa cells, SIRT2 overexpression induced cell proliferation but inhibited apoptosis. For RAS/ERK pathway, SIRT2 knock-down reduced HRAS and inactivated pERK in HEC1A cells, whereas SIRT2 overexpression increased HRAS and activated pERK in Ishikawa cells, suggesting that SIRT2 was implicated in the regulation of RAS/ERK pathway in EC cells. Conclusion: SIRT2 contributes to the EC tumorigenesis, which appears as a potential therapeutic target.


2018 ◽  
Vol 38 (1) ◽  
Author(s):  
Jin-yan Wang ◽  
Qian Zhang ◽  
Dan-dan Wang ◽  
Wei Yan ◽  
Huan-huan Sha ◽  
...  

MiRNAs, small non-coding RNA molecules, were recognized to be associated with the incidence and development of diverse neoplasms. MiRNAs were small non-coding RNAs that could regulate post-transcriptional level by binding to 3′-UTR of target mRNAs. Amongst which, miR-29a was demonstrated that it had significant impact on oncogenicity in various neoplasms through binding to critical genes which enhanced or inhibited the progression of cancers. MiR-29a participated in kinds of physiological and pathological processes, including virus replication, cell proliferation, differentiation, apoptosis, fibrosis, angiogenesis, tumorigenicity, metastasis, drug-resistance, and so on. According to its sufficient sensitivity and specificity, many studies showed that miR-29a might serve as a potential therapeutic target and promising biomarker in various tumors. In this review, we discussed the functions of miR-29a and its potential application in the diagnosis, treatment and stages of carcinoma, which could provide additional insight to develop a novel therapeutic strategy.


QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Rowaida Mohammed Reda M. M Aboushahba ◽  
Fayda Ibrahim Abdel Motaleb ◽  
Ahmed Abdel Aziz Abou-Zeid ◽  
Enas Samir Nabil ◽  
Dalia Abdel-Wahab Mohamed ◽  
...  

ABSTRACT Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths world-wide. There is an increasing need for the identification of novel biomarkers/targets for early diagnosis and for the development of novel chemopreventive and therapeutic agents for CRC. Recently, MACF1 gene has emerged as a potential therapeutic target in cancer as it involved in processes critical for tumor cell proliferation, invasion and metastasis. It is suggested that MACF1 may function in cancers through Wnt signaling. MiR-34a is a well-known tumor suppressor miRNA.miR-34a targets MACF1 gene as a part of the wnt signaling pathway. In this study, 40 colonic tissues were collected from CRC patients (20) and control subjects (20). miR-34a-5p was assessed by real time PCR in all study groups. The results showed highly significant decrease (P < 0.01) in miR-34a relative expression in the CRC group (median RQ 0.13) when compared to the benign group (median RQ 5.3) and the healthy control group (median RQ 19.63). miR-34a mimic and inhibitor were transfected in CaCo-2 cell line and proliferation was assessed. The transfection of the cell line with miR-34a mimic decreased cell proliferation. Our study suggests that miR-34a-5p targets MACF1 gene as a part of the wnt signaling pathway leading to the involvement in the molecular mechanisms of CRC development and progression.


2003 ◽  
Vol 285 (6) ◽  
pp. G1181-G1188 ◽  
Author(s):  
Ki-Sook Park ◽  
Nam-Gu Lee ◽  
Ki-Hoo Lee ◽  
Jeong Taeg Seo ◽  
Kang-Yell Choi

Dietary zinc is an important trace element in the body and is related to both cell proliferation and growth arrest. A recent study found that extracellular zinc-sensing receptors trigger intracellular signal transduction in HT-29 human colorectal cancer cells. However, the signaling mechanism causing this growth regulation by extracellular zinc is not clearly understood. At 10- and 100-μM levels of ZnCl2 treatment, HT-29 cell growth and proliferation increased and decreased, respectively, in a minimally serum-starved medium (MSSM). A lack of significant increase in intracellular zinc levels after zinc treatment suggested that this differential growth regulation of HT-29 cells by extracellular zinc is acquired by receptor-mediated signal transduction. Moreover, this zinc-induced growth regulation was differentially affected by PD-98059, suggesting the involvement of the ERK pathway. Transient ERK activation and subsequent cyclin D1 induction were observed on adding 10 μM ZnCl2 in MSSM in the presence of cell proliferation. On the other hand, prolonged ERK activity was observed with a subsequent increase of cyclin D1 and p21Cip/WAF1 on adding 100 μM ZnCl2 in MSSM, and this was associated with nonproliferation. Moreover, this ERK activation and cyclin D1 and p21Cip/WAF1 induction were abolished by PD-98059 pretreatment. The differential regulations of cell growth, ERK activities, and cyclin D1 and p21Cip/WAF1 inductions were also observed in serum-enriched medium containing higher zinc concentrations. Therefore, differential cell cycle regulator induction occurs by a common ERK pathway in the differential growth regulation of HT-29 cells by extracellular zinc.


Biochemistry ◽  
2005 ◽  
Vol 44 (18) ◽  
pp. 6948-6957 ◽  
Author(s):  
Jiandong Zhang ◽  
Timothy D. Osslund ◽  
Matthew H. Plant ◽  
Christi L. Clogston ◽  
Rebecca E. Nybo ◽  
...  

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 33-33
Author(s):  
Lei Yuan ◽  
Lu Sun ◽  
Yu Zhao ◽  
Hongmei Jing ◽  
Xiaoyan Ke

Background:B7-H6 is a novel co-stimulatory protein that is exclusively expressed on a variety of cancer cells and associated with poor prognosis. T cell lymphoblastic lymphoma (T-LBL) is a highly aggressive hematological malignancy whose treatment requires reliable prognostic biomarkers and therapeutic targets. The rare nature and delayed progression of T-LBL has limited its clinical management. Methods:B7-H6 expression was analyzed by immunohistochemistry (IHC) in 65 T-LBL samples, and its association with clinicopathological characteristics and prognosis was analyzed. Jurkat cell with B7-H6 depletion was constructed to investigate the impact of B7-H6 on cell proliferation, migration, and invasion ability. RNA sequencing was used to explore aberrantly expressing genes. Results:In this study, we used immunohistochemistry to show the expression of B7-H6 in 61.5% (40/65) of the cohort, including 38.5% (25/65) patients with membrane/cytoplasmic expression of B7-H6. Although B7-H6 expression varied across samples and did not correlate with patient survival, it was significantly associated with B symptoms, higher ECOG score (3-4), elevated serum lactate dehydrogenase, and reduced complete remission at interim evaluation. B7-H6 underwent translocation into the nucleus of T-LBL cells and had a specific nuclear localization sequence in the C-terminus. Depleting Jurkat cells of B7-H6 impaired cell proliferation, migration, and invasion. RNAseq showed the differential expression of RAG-1 that could be involved in the tumorigenesis of T-LBL. Conclusions:B7-H6 may serve as a novel prognostic biomarker and therapeutic target of T-LBL. Disclosures Ke: Peking University Third Hospital:Current Employment.


2017 ◽  
Vol 66 (3) ◽  
pp. 676-683 ◽  
Author(s):  
Hongliang Diao ◽  
Zhou Ye ◽  
Renyi Qin

MicroRNAs have been reported to play an important role in tumor development and progression by targeting oncogenes and tumor suppressors. miR-23a has been described as significantly upregulated in multiple cancers and involved in tumorigenesis. The aim of this study was to evaluate the potential roles of miR-23a in pancreatic ductal adenocarcinoma (PDAC). We found that miR-23a level was significantly increased in tissues of PDAC compared with that in the control by real-time PCR. FOXP2 expression was downregulated and inversely correlated with miR-23a. miR-23a directly targeted the 3’-untranslated region of FOXP2 mRNA and repressed its expression. Mechanistically, enhancement of miR-23a by transfection with mimics in Aspc-1 cells significantly promoted cell proliferation and invasion, while miR-23a inhibitors transfection in SW1990 cells induced an inhibitory effect. Moreover, restoration of FOXP2 impaired the pro-proliferation and proinvasion effects of miR-23a, indicating FOXP2 is a direct mediator of miR-23a functions. In conclusion, our findings suggest a novel miR-23a/FOXP2 link contributing to PDAC development and invasion. It may be a potential diagnostic and therapeutic target for PDAC.


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