Research Progress of 70 kDa Ribosomal Protein S6 Kinase (P70S6K) Inhibitors as Effective Therapeutic Tools for Obesity, Type II Diabetes and Cancer

2020 ◽  
Vol 27 (28) ◽  
pp. 4699-4719
Author(s):  
Na Zhang ◽  
Shutao Ma

At present, diseases such as obesity, type Ⅱ diabetes and cancer have brought serious health problems, which are closely related to mTOR pathway. 70 kDa ribosomal protein S6 kinase (p70S6K), as a significant downstream effector of mTOR, mediates protein synthesis, RNA processing, glucose homeostasis, cell growth and apoptosis. Inhibiting the function of p70S6K can reduce the risk of obesity which helps to treat dyslipidemia, enhance insulin sensitivity, and extend the life span of mammals. Therefore, p70S6K has become a potential target for the treatment of these diseases. So far, except for the first p70S6K specific inhibitor PF-4708671 developed by Pfizer and LY2584702 developed by Lilai, all of them are in preclinical research. This paper briefly introduces the general situation of p70S6K and reviews their inhibitors in recent years, which are mainly classified into two categories: natural compounds and synthetic compounds. In particular, their inhibitory activities, structure-activity relationships (SARs) and mechanisms are highlighted.

2006 ◽  
Vol 291 (1) ◽  
pp. E115-E127 ◽  
Author(s):  
Ji Young Kim ◽  
Kristin Tillison ◽  
Jun-Ho Lee ◽  
David A. Rearick ◽  
Cynthia M. Smas

The minimal adipose phenotype of hormone-sensitive lipase (HSL)-null mice suggested that other hormonally responsive lipase(s) were present in adipocytes. Recent studies have characterized a new adipose tissue triglyceride lipase, ATGL/PNPLA2/destnutrin/iPLA2ζ/TTS2.2 (ATGL). We had previously cloned a novel adipose-enriched transcript by differential screening and recently determined its identity with murine ATGL. We report here on the regulation of ATGL by TNF-α and insulin in 3T3-L1 adipocytes and identify ATGL as a target for transcriptional activation by the key adipogenic transcription factor PPARγ. Insulin at 100 nM resulted in a marked decrease in ATGL transcript that was effectively blocked by inhibitors for PI 3-kinase and p70 ribosomal protein S6 kinase. TNF-α treatment decreased ATGL transcript in a time-dependent manner that paralleled TNF-α downregulation of PPARγ with a maximal decrease noted by 6 h. TNF-α effects on ATGL were attenuated by pretreatment with PD-98059, LY-294002, or rapamycin, suggesting involvement of the p44/42 MAP kinase, PI 3-kinase, and p70 ribosomal protein S6 kinase signals. To study transcriptional regulation of ATGL, we cloned 2,979 bp of the murine ATGL 5′-flanking region. Compared with promoterless pGL2-Basic, the −2979/+21 ATGL luciferase construct demonstrated 120- and 40-fold increases in activity in white and brown adipocytes, respectively. Luciferase reporter activities for a series of eight ATGL promoter deletions revealed that the −928/+21, −1738/+21, −1979/+21, and −2979/+21 constructs were transactivated by PPARγ. Our findings identify the novel lipase ATGL to be a target gene for TNF-α and insulin action in adipocytes and reveal that it is subject to transcriptional control by PPARγ-mediated signals.


2019 ◽  
Vol 8 (7) ◽  
pp. 863-869
Author(s):  
Chan Sub Park ◽  
Jihye Choi ◽  
Min-Ki Seong ◽  
Sung-Eun Hong ◽  
Jae-Sung Kim ◽  
...  

Estradiol is a key factor for tumorigenesis and prognosis of hormone receptor-positive breast cancer. Adipocytes are one source of estradiol in patients with breast cancer. Recent studies have shown that phosphorylated ribosomal protein S6 kinase-1 plays a critical role in adipogenesis. Therefore, estrogen depletion therapy might have beneficial effects in phosphorylated ribosomal protein S6 kinase-1-positive breast cancer. This study was conducted to evaluate the value of phosphorylated ribosomal protein S6 kinase-1 as a marker for gonadotropin-releasing hormone agonist treatment, a form of estrogen depletion therapy, for premenopausal patients with HR-positive, human epidermal growth factor receptor 2-negative breast cancer. We reviewed the medical records of 296 premenopausal patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative primary invasive breast cancer treated between 2008 and 2015. Phosphorylated ribosomal protein S6 kinase-1 positivity was defined by immunohistochemical staining scores of 1+, 2+ and 3+, whereas a score of 0 was considered negative. Phosphorylated ribosomal protein S6 kinase-1-positive tumors were found in 74.0% of the patients. In the phosphorylated ribosomal protein S6 kinase-1-positive group, disease-free survival of patients treated with a gonadotropin-releasing hormone agonist was significantly longer than that of patients treated without a gonadotropin-releasing hormone agonist (mean 106.7 months vs mean 91.1 months, P = 0.018). Phosphorylated ribosomal protein S6 kinase-1 is a potential biomarker for predicting the efficacy of gonadotropin-releasing hormone agonist therapy in premenopausal patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer.


2009 ◽  
Vol 27 (1) ◽  
pp. 12-21 ◽  
Author(s):  
Doyil Kim ◽  
Argun Akcakanat ◽  
Gopal Singh ◽  
Chandeshwar Sharma ◽  
Funda Meric-Bernstam

2020 ◽  
Vol 11 (5) ◽  
pp. 583-590
Author(s):  
Yan Yin ◽  
Yuxing Sun ◽  
Lianhua Zhao ◽  
Jinpeng Pan ◽  
Yangbo Feng

Ribosomal protein S6 kinase beta-1 (S6K1) is an attractive therapeutic target.


2020 ◽  
Vol 34 (9) ◽  
pp. 12367-12378 ◽  
Author(s):  
Ying Fang ◽  
Feng Liang ◽  
Renqiang Yuan ◽  
Qi Zhu ◽  
Shufang Cai ◽  
...  

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